WorldWideScience

Sample records for nozzle pattern test

  1. Nuclear thermal rocket nozzle testing and evaluation program

    Science.gov (United States)

    Davidian, Kenneth O.; Kacynski, Kenneth J.

    1993-01-01

    Performance characteristics of the Nuclear Thermal Rocket can be enhanced through the use of unconventional nozzles as part of the propulsion system. The Nuclear Thermal Rocket nozzle testing and evaluation program being conducted at the NASA Lewis is outlined and the advantages of a plug nozzle are described. A facility description, experimental designs and schematics are given. Results of pretest performance analyses show that high nozzle performance can be attained despite substantial nozzle length reduction through the use of plug nozzles as compared to a convergent-divergent nozzle. Pretest measurement uncertainty analyses indicate that specific impulse values are expected to be within + or - 1.17 pct.

  2. Ultrasonic pattern recognition study of feedwater nozzle inner radius indication

    International Nuclear Information System (INIS)

    Yoneyama, H.; Takama, S.; Kishigami, M.; Sasahara, T.; Ando, H.

    1983-01-01

    A study was made to distinguish defects on feed-water nozzle inner radius from noise echo caused by stainless steel cladding by using ultrasonic pattern recognition method with frequency analysis technique. Experiment has been successfully performed on flat clad plates and nozzle mock-up containing fatigue cracks and the following results which shows the high capability of frequency analysis technique are obtained

  3. Nozzle

    Science.gov (United States)

    Chen, Alexander G.; Cohen, Jeffrey M.

    2009-06-16

    A fuel injector has a number of groups of nozzles. The groups are generally concentric with an injector axis. Each nozzle defines a gas flowpath having an outlet for discharging a fuel/air mixture jet. There are means for introducing the fuel to the air. One or more groups of the nozzles are oriented to direct the associated jets skew to the injector axis.

  4. Biannular Airbreathing Nozzle Rig (BANR) facility checkout and plug nozzle performance test data

    Science.gov (United States)

    Cummings, Chase B.

    2010-09-01

    The motivation for development of a supersonic business jet (SSBJ) platform lies in its ability to create a paradigm shift in the speed and reach of commercial, private, and government travel. A full understanding of the performance capabilities of exhaust nozzle configurations intended for use in potential SSBJ propulsion systems is critical to the design of an aircraft of this type. Purdue University's newly operational Biannular Airbreathing Nozzle Rig (BANR) is a highly capable facility devoted to the testing of subscale nozzles of this type. The high accuracy, six-axis force measurement system and complementary mass flowrate measurement capabilities of the BANR facility make it rather ideally suited for exhaust nozzle performance appraisal. Detailed accounts pertaining to methods utilized in the proper checkout of these diagnostic capabilities are contained herein. Efforts to quantify uncertainties associated with critical BANR test measurements are recounted, as well. Results of a second hot-fire test campaign of a subscale Gulfstream Aerospace Corporation (GAC) axisymmetric, shrouded plug nozzle are presented. Determined test article performance parameters (nozzle thrust efficiencies and discharge coefficients) are compared to those of a previous test campaign and numerical simulations of the experimental set-up. Recently acquired data is compared to published findings pertaining to plug nozzle experiments of similar scale and operating range. Suggestions relating to the future advancement and improvement of the BANR facility are provided. Lessons learned with regards to test operations and calibration procedures are divulged in an attempt to aid future facility users, as well.

  5. Jet-Surface Interaction: High Aspect Ratio Nozzle Test, Nozzle Design and Preliminary Data

    Science.gov (United States)

    Brown, Clifford; Dippold, Vance

    2015-01-01

    The Jet-Surface Interaction High Aspect Ratio (JSI-HAR) nozzle test is part of an ongoing effort to measure and predict the noise created when an aircraft engine exhausts close to an airframe surface. The JSI-HAR test is focused on parameters derived from the Turbo-electric Distributed Propulsion (TeDP) concept aircraft which include a high-aspect ratio mailslot exhaust nozzle, internal septa, and an aft deck. The size and mass flow rate limits of the test rig also limited the test nozzle to a 16:1 aspect ratio, half the approximately 32:1 on the TeDP concept. Also, unlike the aircraft, the test nozzle must transition from a single round duct on the High Flow Jet Exit Rig, located in the AeroAcoustic Propulsion Laboratory at the NASA Glenn Research Center, to the rectangular shape at the nozzle exit. A parametric nozzle design method was developed to design three low noise round-to-rectangular transitions, with 8:1, 12:1, and 16: aspect ratios, that minimizes flow separations and shocks while providing a flat flow profile at the nozzle exit. These designs validated using the WIND-US CFD code. A preliminary analysis of the test data shows that the actual flow profile is close to that predicted and that the noise results appear consistent with data from previous, smaller scale, tests. The JSI-HAR test is ongoing through October 2015. The results shown in the presentation are intended to provide an overview of the test and a first look at the preliminary results.

  6. Fluid Structure Interaction in a Cold Flow Test and Transient CFD Analysis of Out-of-Round Nozzles

    Science.gov (United States)

    Ruf, Joseph; Brown, Andrew; McDaniels, David; Wang, Ten-See

    2010-01-01

    This viewgraph presentation describes two nozzle fluid flow interactions. They include: 1) Cold flow nozzle tests with fluid-structure interaction at nozzle separated flow; and 2) CFD analysis for nozzle flow and side loads of nozzle extensions with various out-of-round cases.

  7. Analysis, design and testing of high pressure waterjet nozzles

    Science.gov (United States)

    Mazzoleni, Andre P.

    1996-01-01

    The Hydroblast Research Cell at MSFC is both a research and a processing facility. The cell is used to investigate fundamental phenomena associated with waterjets as well as to clean hardware for various NASA and contractor projects. In the area of research, investigations are made regarding the use of high pressure waterjets to strip paint, grease, adhesive and thermal spray coatings from various substrates. Current industrial methods of cleaning often use ozone depleting chemicals (ODC) such as chlorinated solvents, and high pressure waterjet cleaning has proven to be a viable alternative. Standard methods of waterjet cleaning use hand held or robotically controlled nozzles. The nozzles used can be single-stream or multijet nozzles, and the multijet nozzles may be mounted in a rotating head or arranged in a fan-type shape. We consider in this paper the use of a rotating, multijet, high pressure water nozzle which is robotically controlled. This method enables rapid cleaning of a large area, but problems such as incomplete coverage (e.g. the formation of 'islands' of material not cleaned) and damage to the substrate from the waterjet have been observed. In addition, current stripping operations require the nozzle to be placed at a standoff distance of approximately 2 inches in order to achieve adequate performance. This close proximity of the nozzle to the target to be cleaned poses risks to the nozzle and the target in the event of robot error or the striking of unanticipated extrusions on the target surface as the nozzle sweeps past. Two key motivations of this research are to eliminate the formation of 'coating islands' and to increase the allowable standoff distance of the nozzle.

  8. Jet-Surface Interaction - High Aspect Ratio Nozzle Test: Test Summary

    Science.gov (United States)

    Brown, Clifford A.

    2016-01-01

    The Jet-Surface Interaction High Aspect Ratio Nozzle Test was conducted in the Aero-Acoustic Propulsion Laboratory at the NASA Glenn Research Center in the fall of 2015. There were four primary goals specified for this test: (1) extend the current noise database for rectangular nozzles to higher aspect ratios, (2) verify data previously acquired at small-scale with data from a larger model, (3) acquired jet-surface interaction noise data suitable for creating verifying empirical noise models and (4) investigate the effect of nozzle septa on the jet-mixing and jet-surface interaction noise. These slides give a summary of the test with representative results for each goal.

  9. Pressure drop performance evaluation for test assemblies with the newly developed top and bottom nozzles

    International Nuclear Information System (INIS)

    Lee, S. K.; Park, N. K.; Su, J. M.; Kim, H. K.; Lee, J. N.; Kim, K. T.

    2003-01-01

    To perform the hydraulic test for the newly developed top and bottom nozzles, two kinds of test assemblies were manufactured i. e. one is the test assembly which has the newly developed top and bottom nozzles and the other is Guardian test assembly which is commercially in mass production now. The test results show that the test assembly with one top nozzle and two bottom nozzles has a greater pressure loss coefficient than Guardian test assembly by 60.9% and 90.4% at the bottom nozzle location. This cause is due to the debris filtering plate for bottom nozzle to improve a filtering efficiency aginst foreign material. In the region of mid grid and top nozzle, there is no difference in pressure loss coefficient between the test assemblies since the componet features in these regions are very similar or same each other. The loss coefficients are 14.2% and 21.9% for model A and B respectively in the scale of test assembly, and the value would be within the 10% in the scale of real fuel assembly. As a result of hydraulic performance evaluation, model A is superior to model B

  10. Coupled CFD-Thermal Analysis of Erosion Patterns Resulting from Nozzle Wedgeouts on the SRTMV-N2

    Science.gov (United States)

    Ables, Catherine; Davis, Philip

    2014-01-01

    The objective of this analysis was to study the effects of the erosion patterns from the introduction of nozzle flaws machined into the nozzle of the SRTMV-N2 (Solid Rocket Test Motor V Nozzle 2). The SRTMV-N2 motor was a single segment static subscale solid rocket motor used to further develop the RSRMV (Redesigned Solid Rocket Motor V Segment). Two flaws or "wedgeouts" were placed in the nozzle inlet parallel to the ply angles of that section to study erosion effects. One wedgeout was placed in the nose cap region and the other placed in the inlet ring on the opposite side of the bondline, separated 180 degrees circumferentially. A coupled CFD (Computational Fluid Analysis)-thermal iterative analytical approach was utilized at the wedgeouts to analyze the erosion profile during the burn time. The iterative CFD thermal approach was applied at five second intervals throughout the motor burn. The coupled fluid thermal boundary conditions were derived from a steady state CFD solution at the beginning of the interval. The derived heat fluxes were then applied along the surface and a transient thermal solution was developed to characterize the material response over the specified interval. Eroded profiles of each of the nozzle's wedgeouts and the original contour were created at each of the specified intervals. The final iteration of the erosion profile showed that both wedgeouts were "washedout," indicating that the erosion profile of the wedgeout had rejoined the original eroded contour, leaving no trace of the wedgeouts post fire. This analytical assessment agreed with post-fire observations made of the SRTMV-N2 wedgeouts, which noted a smooth eroded contour.

  11. Development and testing of a relay nozzle concept for air-jet weaving

    Science.gov (United States)

    Münkel, A.; Gloy, Y. S.; Gries, T.

    2017-10-01

    The textile industry is an energy intensive branch of industry. Increasing energy costs are a challenge for textile manufacturers as well as for the developers of textile production machines [1]. Air jet weaving is the most productive method to produce woven fabrics. However, air-jet weaving machines have a significantly higher level of energy consumption compared to other weaving machines. Approximately 80% of compressed air is consumed by the relay nozzles. Therefore, there are different approaches to reduce the consumption of compressed air and to increase the energy efficiency of air-jet looms [2] At the Institut für Textiltechnik der RWTH Aachen University, Aachen new relay nozzle concepts have been developed. Based on Computational Fluid Dynamics (CFD) the concepts were further developed with the result of an energy-efficient relay nozzle concept. The simulations have shown the potential energy savings up to 60 % compared to conventional relay nozzles. Furthermore, practical validations of these simulation results were done. The velocity, stagnation pressure and volume flow were measured in the reed canal. The optimal position regarding the injection angle and high, as well as the distance between two relay nozzles were identified with the results of the measurements. In addition, the relay nozzles were tested in the industrial environment. These tests have shown a low error rate which is comparable conventional relay nozzle concepts. Furthermore, exergy savings up to 49% has been measured.

  12. Development and Testing of Carbon-Carbon Nozzle Extensions for Upper Stage Liquid Rocket Engines

    Science.gov (United States)

    Valentine, Peter G.; Gradl, Paul R.; Greene, Sandra E.

    2017-01-01

    Carbon-carbon (C-C) composite nozzle extensions are of interest for use on a variety of launch vehicle upper stage engines and in-space propulsion systems. The C-C nozzle extension technology and test capabilities being developed are intended to support National Aeronautics and Space Administration (NASA) and Department of Defense (DOD) requirements, as well as those of the broader Commercial Space industry. For NASA, C-C nozzle extension technology development primarily supports the NASA Space Launch System (SLS) and NASA's Commercial Space partners. Marshall Space Flight Center (MSFC) efforts are aimed at both (a) further developing the technology and databases needed to enable the use of composite nozzle extensions on cryogenic upper stage engines, and (b) developing and demonstrating low-cost capabilities for testing and qualifying composite nozzle extensions. Recent, on-going, and potential future work supporting NASA, DOD, and Commercial Space needs will be discussed. Information to be presented will include (a) recent and on-going mechanical, thermal, and hot-fire testing, as well as (b) potential future efforts to further develop and qualify domestic C-C nozzle extension solutions for the various upper stage engines under development.

  13. Within-band spray distribution of nozzles used for herbaceous plant control

    Science.gov (United States)

    James H. Miller

    1994-01-01

    Abstract. Described are the spray patterns of nozzles setup for banded herbaceous plant control treatments. Spraying Systems Company nozzles. were tested, but similar nozzles are available from other manufacturers. Desirable traits were considered to be as follows: an even distribution pattern, low volume, low height, large droplets, and a single...

  14. Fracture analyses and test of regions with nozzle and hole and curvature influence in nuclear vessel

    International Nuclear Information System (INIS)

    Wang Baisong; Xu Dinggen; Ye Weijuan; Hu Yinbiao; Liang Xingyun; Gu Shaode; Zhou Peiying

    1993-08-01

    For the calculations of stress intensity factor K 1 of surface crack in the regions with nozzle and hole and the curvature influence on nuclear vessel, a improved 3-D collapsed isoparametric singular element with quarter-points was presented. The square root singularity in the vertical planes of crack was derived. The methods of transitional element and calculating K 1 from displacements were extensively used in 3- D case. The SIF K 1 of the corner crack in inner wall of the nozzle of RPV (reactor pressure vessel) for a typical 300 MW nuclear plant was calculated, and it was verified by 3-D photo-elastic test and diffusion of light test. The engineering fracture analysis and evaluation of the outside surface crack in the circular are transitional region of the head flange of RPV are also completed

  15. Subscale Carbon-Carbon Nozzle Extension Development and Hot Fire Testing in Support of Upper Stage Liquid Rocket Engines

    Science.gov (United States)

    Gradl, Paul; Valentine, Peter; Crisanti, Matthew; Greene, Sandy Elam

    2016-01-01

    Upper stage and in-space liquid rocket engines are optimized for performance through the use of high area ratio nozzles to fully expand combustion gases to low exit pressures increasing exhaust velocities. Due to the large size of such nozzles and the related engine performance requirements, carbon-carbon (C/C) composite nozzle extensions are being considered for use in order to reduce weight impacts. NASA and industry partner Carbon-Carbon Advanced Technologies (C-CAT) are working towards advancing the technology readiness level of large-scale, domestically-fabricated, C/C nozzle extensions. These C/C extensions have the ability to reduce the overall costs of extensions relative to heritage metallic and composite extensions and to decrease weight by 50%. Material process and coating developments have advanced over the last several years, but hot fire testing to fully evaluate C/C nozzle extensions in relevant environments has been very limited. NASA and C-CAT have designed, fabricated and hot fire tested multiple subscale nozzle extension test articles of various C/C material systems, with the goal of assessing and advancing the manufacturability of these domestically producible materials as well as characterizing their performance when subjected to the typical environments found in a variety of liquid rocket and scramjet engines. Testing at the MSFC Test Stand 115 evaluated heritage and state-of-the-art C/C materials and coatings, demonstrating the capabilities of the high temperature materials and their fabrication methods. This paper discusses the design and fabrication of the 1.2k-lbf sized carbon-carbon nozzle extensions, provides an overview of the test campaign, presents results of the hot fire testing, and discusses potential follow-on development work.

  16. Wear characterization of abrasive waterjet nozzles and nozzle materials

    Science.gov (United States)

    Nanduri, Madhusarathi

    Parameters that influence nozzle wear in the abrasive water jet (AWJ) environment were identified and classified into nozzle geometric, AWJ system, and nozzle material categories. Regular and accelerated wear test procedures were developed to study nozzle wear under actual and simulated conditions, respectively. Long term tests, using garnet abrasive, were conducted to validate the accelerated test procedure. In addition to exit diameter growth, two new measures of wear, nozzle weight loss and nozzle bore profiles were shown to be invaluable in characterizing and explaining the phenomena of nozzle wear. By conducting nozzle wear tests, the effects of nozzle geometric, and AWJ system parameters on nozzle wear were systematically investigated. An empirical model was developed for nozzle weight loss rate. To understand the response of nozzle materials under varying AWJ system conditions, erosion tests were conducted on samples of typical nozzle materials. The effect of factors such as jet impingement angle, abrasive type, abrasive size, abrasive flow rate, water pressure, traverse speed, and target material was evaluated. Scanning electron microscopy was performed on eroded samples as well as worn nozzles to understand the wear mechanisms. The dominant wear mechanism observed was grain pullout. Erosion models were reviewed and along the lines of classical erosion theories a semi-empirical model, suitable for erosion of nozzle materials under AWJ impact, was developed. The erosion data correlated very well with the developed model. Finally, the cutting efficiency of AWJ nozzles was investigated in conjunction with nozzle wear. The cutting efficiency of a nozzle deteriorates as it wears. There is a direct correlation between nozzle wear and cutting efficiency. The operating conditions that produce the most efficient jets also cause the most wear in the nozzle.

  17. Hot wire anemometer measurements in the unheated air flow tests of the SRB nozzle-to-case joint

    Science.gov (United States)

    Ramachandran, N.

    1988-01-01

    Hot-Wire Anemometer measurements made in the Solid Rocket Booster (SRB) nozzle-to-case joint are discussed. The study was undertaken to glean additional information on the circumferential flow induced in the SRB nozzle joint and the effect of this flow on the insulation bonding flaws. The tests were conducted on a full-scale, 2-D representation of a 65-in long segment of the SRB nozzle joint, with unheated air as the working fluid. Both the flight Mach number and Reynolds number were matched simultaneously and different pressure gradients imposed along the joint face were investigated. Hot-wire anemometers were used to obtain velocity data for different joint gaps and debond configurations. The procedure adopted for hot-wire calibration and use is outlined and the results from the tests summarized.

  18. Design and cold flow test of a scramjet nozzle with nonuniform inflow

    Science.gov (United States)

    Mo, Jianwei; Xu, Jinglei; Quan, Zhibin; Yu, Kaikai; Lv, Zheng

    2015-03-01

    Dramatic differences in lift and pitching moment of a scramjet nozzle are inevitably produced when its inlet is nonuniform. A rotational method of characteristics computer program which takes into account the non-uniform inflow effects has been developed for designing asymmetric scramjet nozzles. Typical design cases with a given non-uniform Mach number profile and the corresponding mass-weighted average uniform Mach number profile were developed. Then, three-dimensional computational fluid dynamics analyses and cold flow experimental measurements were conducted to quantify performance improvement of the nozzle with the non-uniform design. Both the computation and experiment results indicate that the nozzle design with the non-uniform Mach number profile always exhibit better performance than the design with the uniform Mach number profile, particularly for lift and pitching moment. Compared with the nozzle design with uniform inflow, the improvement of axial thrust coefficient in the nozzle design with non-uniform inflow is approximately 1.75% at the design point, with a nozzle pressure ratio of 35. Moreover, the benefits on lift and pitching moment coefficients of the nozzle design with non-uniform inflow are approximately 6.51% and 6.35% at the design point, respectively. These results confirm that considering non-uniform distribution of the entrance flow parameters of a scramjet nozzle is necessary.

  19. Test of 6-in.-thick pressure vessels. Series 4: intermediate test vessels V-5 and V-9 with inside nozzle corner cracks

    International Nuclear Information System (INIS)

    Merkle, J.G.; Robinson, G.C.; Holz, P.P.; Smith, J.E.

    1977-01-01

    Failure testing is described for two 99-cm-diam (39-in.), 15.2-cm-thick (6-in.) steel pressure vessels, each containing one flawed nozzle. Vessel V-5 was tested at 88 0 C (190 0 F) and failed by leaking without fracturing after extensive stable crack growth. Vessel V-9 was tested at 25 0 C (75 0 F) and failed by fracturing. Material properties measured before the tests were used for pretest and posttest fracture analyses. Test results supported by analysis indicate that inside nozzle corner cracks are not subject to plane strain under pressure loading. The preparation of inside nozzle corner cracks is described in detail. Extensive experimental data are tabulated and plotted

  20. Test of 6-in. -thick pressure vessels. Series 4: intermediate test vessels V-5 and V-9 with inside nozzle corner cracks. [BWR and PWR

    Energy Technology Data Exchange (ETDEWEB)

    Merkle, J.G.; Robinson, G.C.; Holz, P.P.; Smith, J.E.

    1977-08-01

    Failure testing is described for two 99-cm-diam (39-in.), 15.2-cm-thick (6-in.) steel pressure vessels, each containing one flawed nozzle. Vessel V-5 was tested at 88/sup 0/C (190/sup 0/F) and failed by leaking without fracturing after extensive stable crack growth. Vessel V-9 was tested at 25/sup 0/C (75/sup 0/F) and failed by fracturing. Material properties measured before the tests were used for pretest and posttest fracture analyses. Test results supported by analysis indicate that inside nozzle corner cracks are not subject to plane strain under pressure loading. The preparation of inside nozzle corner cracks is described in detail. Extensive experimental data are tabulated and plotted.

  1. Fabrication and Testing of Low Cost 2D Carbon-Carbon Nozzle Extensions at NASA/MSFC

    Science.gov (United States)

    Greene, Sandra Elam; Shigley, John K.; George, Russ; Roberts, Robert

    2015-01-01

    Subscale liquid engine tests were conducted at NASA/MSFC using a 1.2 Klbf engine with liquid oxygen (LOX) and gaseous hydrogen. Testing was performed for main-stage durations ranging from 10 to 160 seconds at a chamber pressure of 550 psia and a mixture ratio of 5.7. Operating the engine in this manner demonstrated a new and affordable test capability for evaluating subscale nozzles by exposing them to long duration tests. A series of 2D C-C nozzle extensions were manufactured, oxidation protection applied and then tested on a liquid engine test facility at NASA/MSFC. The C-C nozzle extensions had oxidation protection applied using three very distinct methods with a wide range of costs and process times: SiC via Polymer Impregnation & Pyrolysis (PIP), Air Plasma Spray (APS) and Melt Infiltration. The tested extensions were about 6" long with an exit plane ID of about 6.6". The test results, material properties and performance of the 2D C-C extensions and attachment features will be discussed.

  2. Nozzle seal

    International Nuclear Information System (INIS)

    Groff, R.D.; Vatovec, R.J.

    1978-01-01

    In an illustrative embodiment of the invention, a nuclear reactor pressure vessel, having an internal hoop from which the heated coolant emerges from the reactor core and passes through to the reactor outlet nozzles, is provided with annular sealing members operatively disposed between the outlet nozzle and the hoop and partly within a retaining annulus formed in the hoop. The sealing members are biased against the pressure vessel and the hoop and one of the sealing members is provided with a piston type pressure ring sealing member which effectively closes the path between the inlet and outlet coolants in the region about the outlet nozzle establishing a leak-proof condition. Furthermore, the flexible responsiveness of the seal assures that the seal will not structurally couple the hoop to the pressure vessel

  3. Scramjet Nozzles

    Science.gov (United States)

    2010-09-01

    integration et gestion thermique ) 14. ABSTRACT The lecture is given in four parts, each being a step in the process of nozzle design, and within each part...nose acts as a compressor at flight Mach numbers below 2.5, feeding a transfer duct which moves air rearwards below the 40m cabin to ramjet combustors...the fuselage, but with fuel tanks rather than a cabin above the transfer duct. The single nozzle along the wing trailing edge, highlighted in blue, was

  4. Fuel nozzle assembly

    Science.gov (United States)

    Johnson, Thomas Edward [Greer, SC; Ziminsky, Willy Steve [Simpsonville, SC; Lacey, Benjamin Paul [Greer, SC; York, William David [Greer, SC; Stevenson, Christian Xavier [Inman, SC

    2011-08-30

    A fuel nozzle assembly is provided. The assembly includes an outer nozzle body having a first end and a second end and at least one inner nozzle tube having a first end and a second end. One of the nozzle body or nozzle tube includes a fuel plenum and a fuel passage extending therefrom, while the other of the nozzle body or nozzle tube includes a fuel injection hole slidably aligned with the fuel passage to form a fuel flow path therebetween at an interface between the body and the tube. The nozzle body and the nozzle tube are fixed against relative movement at the first ends of the nozzle body and nozzle tube, enabling the fuel flow path to close at the interface due to thermal growth after a flame enters the nozzle tube.

  5. Experimental characterization of spin motor nozzle flow.

    Energy Technology Data Exchange (ETDEWEB)

    Erven, Rocky J.; Peterson, Carl Williams; Henfling, John Francis

    2006-11-01

    The Mach number in the inviscid core of the flow exiting scarfed supersonic nozzles was measured using pitot probes. Nozzle characterization experiments were conducted in a modified section of an obsolete M = 7.3 test section/nozzle assembly on Sandia's Hypersonic Wind Tunnel. By capitalizing on existing hardware, the cost and time required for tunnel modifications were significantly reduced. Repeatability of pitot pressure measurements was excellent, and instrumentation errors were reduced by optimizing the pressure range of the transducers used for each test run. Bias errors in probe position prevented us from performing a successful in situ calibration of probe angle effects using pitot probes placed at an angle to the nozzle centerline. The abrupt throat geometry used in the Baseline and Configuration A and B nozzles modeled the throat geometry of the flight vehicle's spin motor nozzles. Survey data indicates that small (''unmeasurable'') differences in the nozzle throat geometries produced measurable flow asymmetries and differences in the flow fields generated by supposedly identical nozzles. Therefore, data from the Baseline and Configuration A and B nozzles cannot be used for computational fluid dynamics (CFD) code validation. Configuration C and D nozzles replaced the abrupt throat geometry of Baseline and Configuration A and B nozzles with a 0.500-inch streamwise radius of curvature in the throat region. This throat geometry eliminated the flow asymmetries, flow separation in the nozzle throat, and measurable differences between the flow fields from identical nozzles that were observed in Baseline/A/B nozzles. Data from Configuration C and D nozzles can be used for CFD code validation.

  6. Rocket engine high-enthalpy flow simulation using heated CO2 gas to verify the development of a rocket nozzle and combustion tests

    Science.gov (United States)

    Takeishi, K.; Ishizaka, K.; Okamoto, J.; Watanabe, Y.

    2017-03-01

    The LE-7A engine is the first-stage engine of the Japanese-made H-IIA launch vehicle. This engine has been developed by improving and reducing the price of the LE-7 engine used in the H-II launch vehicle. In the qualification combustion tests, the original designed LE-7A (LE-7A-OR) engine experienced two major problems, a large side load in the transient state of engine start and stop and melt on nozzle generative cooling tubes. The reason for the troubles of the LE-7A-OR engine was investigated by conducting experimental and numerical studies. In actual engine conditions, the main hot gas stream is a heated steam. Furthermore, the main stream temperature in the nozzle changes from approximately 3500 K at the throat to 500 K at the exit. In such a case, the specific heat ratio changes depending on the temperature. A similarity of the Mach number should be considered when conducting a model flow test with a similar flow condition of the Mach number between an actual engine combustion test and a model flow test. High-speed flow tests were conducted using CO2 gas heated up to 673 K as a working fluid and a 1:12 sub-scaled model nozzle of the LE-7A-OR engine configuration. The problems of the side force and the conducted form of the shock waves generated in the nozzle of the LE-7A-OR engine during engine start and stop were reproduced by the model tests of experimental and numerical investigations. This study presented that the model flow test using heated CO2 gas is useful and effective in verifying the numerical analysis and the design verification before actual engine combustion tests.

  7. Ice Control with Brine Spread with Nozzles on Highways

    DEFF Research Database (Denmark)

    Bolet, Lars; Fonnesbech, Jens Kristian

    2010-01-01

    During the years 1996-2006, the former county of Funen, Denmark, gradually replaced pre-wetted salt with brine spread with nozzles as anti-icing agent in all her ice control activities. The replacement related to 1000 kilometres of highways. Jeopardizing neither road safety nor traffic flow...... spreading on a highway with traffic. A total of 800 spots were measured for residual salt for every spreader. The measurements and the spread pattern for brine spreading with nozzles were so precisely, that we learned: “When there is moisture, water or ice on the road, we need to take into account...... that the salt will run from the high level of the road to the lower level”. In the test the salt moved 1 meter in 3 hours. The knowledge gained from the measurements in the county of Funen - brine spread with nozzles, spreading salt to high level of the road and using GPS controlled spreading – was implemented...

  8. Status of Nozzle Aerodynamic Technology at MSFC

    Science.gov (United States)

    Ruf, Joseph H.; McDaniels, David M.; Smith, Bud; Owens, Zachary

    2002-01-01

    This viewgraph presentation provides information on the status of nozzle aerodynamic technology at MSFC (Marshall Space Flight Center). The objectives of this presentation were to provide insight into MSFC in-house nozzle aerodynamic technology, design, analysis, and testing. Under CDDF (Center Director's Discretionary Fund), 'Altitude Compensating Nozzle Technology', are the following tasks: Development of in-house ACN (Altitude Compensating Nozzle) aerodynamic design capability; Building in-house experience for all aspects of ACN via End-to-End Nozzle Test Program; Obtaining Experimental Data for Annular Aerospike: Thrust eta, TVC (thrust vector control) capability and surface pressures. To support selection/optimization of future Launch Vehicle propulsion we needed a parametric design and performance tool for ACN. We chose to start with the ACN Aerospike Nozzles.

  9. Cold spray nozzle design

    Science.gov (United States)

    Haynes, Jeffrey D [Stuart, FL; Sanders, Stuart A [Palm Beach Gardens, FL

    2009-06-09

    A nozzle for use in a cold spray technique is described. The nozzle has a passageway for spraying a powder material, the passageway having a converging section and a diverging section, and at least the diverging section being formed from polybenzimidazole. In one embodiment of the nozzle, the converging section is also formed from polybenzimidazole.

  10. Optimized design of a hypersonic nozzle

    Science.gov (United States)

    Krishnamurthy, Ramesh

    1994-01-01

    Conventional procedures for designing nozzles involve the design of an inviscid contour (using the method of characteristics) that is corrected with a displacement thickness calculated from boundary-layer theory. However, nozzles designed using this classical procedure have been shown to exhibit poor flow quality at Mach numbers characteristic of hypersonic applications. The nozzle to be designed will be a part of the NASA HYPULSE facility which is being used for hypervelocity flight research. Thus, the flow quality of the nozzle is a critical question that needs to be addressed. Design of nozzles for hypersonic applications requires a proper assessment of the effects of the thick boundary layer on the inviscid flowfield. Since the flow field is largely supersonic, the parabolized form of the Navier-Stokes (PNS) equations can be used. The requirement of a uniform flow at the exit plane of the nozzle can be used to define an objective function as part of an optimization procedure. The design procedure used in this study involves the coupling of a nonlinear (least-squares) optimization algorithm with an efficient, explicit PNS solver. The thick boundary layers growing on the walls of the nozzle limit the extent of the usable core region (region with uniform flow) for testing models (especially rectangular). In order to maximize the region of uniform flow, it was decided to have the exit plane of this nozzle to be (nearly) rectangular. Thus, an additional constraint on the nozzle shape resulted, namely the nozzle will have a shape transitioning from a circular one at the inlet to that of a rectangle at the exit. In order to provide for a smooth shape transition, the cross sectional contour of the nozzle is defined by a superellipse. The nozzle is taken to be a meter in length. The axial variations of the major and minor radii of the superellipse are governed by cubic splines. The design parameters are the coefficients of the splines associated with the local nozzle

  11. Parametric Study of Sealant Nozzle

    Science.gov (United States)

    Yamamoto, Yoshimi

    It has become apparent in recent years the advancement of manufacturing processes in the aerospace industry. Sealant nozzles are a critical device in the use of fuel tank applications for optimal bonds and for ground service support and repair. Sealants has always been a challenging area for optimizing and understanding the flow patterns. A parametric study was conducted to better understand geometric effects of sealant flow and to determine whether the sealant rheology can be numerically modeled. The Star-CCM+ software was used to successfully develop the parametric model, material model, physics continua, and simulate the fluid flow for the sealant nozzle. The simulation results of Semco sealant nozzles showed the geometric effects of fluid flow patterns and the influences from conical area reduction, tip length, inlet diameter, and tip angle parameters. A smaller outlet diameter induced maximum outlet velocity at the exit, and contributed to a high pressure drop. The conical area reduction, tip angle and inlet diameter contributed most to viscosity variation phenomenon. Developing and simulating 2 different flow models (Segregated Flow and Viscous Flow) proved that both can be used to obtain comparable velocity and pressure drop results, however; differences are seen visually in the non-uniformity of the velocity and viscosity fields for the Viscous Flow Model (VFM). A comprehensive simulation setup for sealant nozzles was developed so other analysts can utilize the data.

  12. Palo Verde Unit 3 BMI nozzle modification

    International Nuclear Information System (INIS)

    Waskey, D.

    2015-01-01

    The 61 BMI (Bottom Mount Instrumentation) nozzles of the unit 3 of the Palo Verde plant have been examined through ASME Code Case N722. The nozzle 3 was the only one with leakage noted. The ultrasound testing results are characteristic of PWSCC (Primary Water Stress Corrosion Cracking). The initiation likely occurred at a weld defect which was exposed to the primary water environment resulting in PWSCC. All other nozzles (60) showed no unacceptable indications. Concerning nozzle 3 one crack in J-groove weld connected large defect to primary water. An environmental model has been used to simulate and optimize the repair. The AREVA crew was on site 18 days after contract award and the job was completed in 12 days, 30 hours ahead of baseline schedule. This series of slides describes the examination of the BMI nozzles, the repair steps, and alternative design concepts

  13. Padrão de distribuição da calda produzida pela ponta de pulverização do tipo jato plano (8002 em função do espaçamento entre bicos Spray distribution pattern of flat fan tip (8002 at different spacing between nozzles

    Directory of Open Access Journals (Sweden)

    A.L.S. Lacerda

    2001-12-01

    Full Text Available O presente trabalho foi desenvolvido no laboratório de Engenharia do Departamento de Engenharia Rural da Escola Superior de Agricultura "Luiz de Queiroz" (USP/ESALQ, Piracicaba-SP, com o objetivo de estudar o padrão de distribuição da ponta de pulverização do tipo jato plano (leque 8002, em função das distâncias entre os bicos. Para isso, foram colocados 10 bicos sobre uma mesa de prova, um de cada vez, a uma altura fixa de 45 cm, nos espaçamentos de 10 a 80 cm. Os volumes coletados em cada uma das canaletas serviram para calcular o coeficiente de variação e iniciar o estudo do espaçamento adequado. Após os testes realizados, pôde-se concluir que o bico tipo jato plano 8002 mostrou melhor distribuição em espaçamento de 50 cm, com menor coeficiente de variação (6,88% a uma altura fixa de 45 cm e pressão regulada a 279,3 Kpa, registrada no manômetro.This work was carried out at the Department of Agricultural Engineering, Escola Superior de Agricultura "Luiz de Queiroz" (USP/ESALQ, Piracicaba-SP, Brazil. The objective of this research was to study the spray pattern of the flat fan tip (8002 at different spacings between nozzles. Thus, ten nozzles were placed on a tilted foil, one at a time, at a fixed height of 45 cm, with spacings varying from 10 to 80 cm. Nozzle output was collected separately from each nozzle and used to calculate the variation coefficient and determine the more appropriate spacing between nozzles. It was concluded that, 50 cm-spaced flat fan tips (8002 showed the best spray pattern with a smaller variation coefficient at a fixed height of 45 cm and pressure regulated at 279.3 kPa registered in the manometer.

  14. Antenna Pattern Impact on MIMO OTA Testing

    DEFF Research Database (Denmark)

    Fan, Wei; Nielsen, Jesper Ødum; Franek, Ondrej

    2013-01-01

    This paper investigates the impact of the DUT antenna pattern on the test area performance for multi-probe based MIMO OTA setup in terms of received voltage and spatial correlation. The plane wave synthesis (PWS) technique has been proposed for vertical polarization in the literature, where...

  15. Uranium enrichment by the separation nozzle process

    International Nuclear Information System (INIS)

    Becker, E.W.; Bier, W.; Ehrfeld, W.; Schubert, K.; Schuette, R.; Seidel, D.

    1975-11-01

    The separation nozzle process for the enrichment of the light uranium isotope U-235 has been developed at the Karlsruhe Nuclear Research Center as an alternative to the gaseous diffusion and centrifuge processes. Since 1970 the STEAG company, Essen, has been involved in the commercial implementation of the nozzle process. A first separation nozzle process. A first separation nozzle demonstration plant with a separative capacity of 180 t SWU/a shall be erected in Brazil with the participation of the Brazilian company NUCLEBRAS and the German companies STEAG and INTERATOM. Methods for the mass production of separation elements were developed by industry and extensive performance tests were carried out on commercially fabricated separation elements. Two prototype separative stages were successfully tested in Karlsruhe. Besides further plant components, a prototype of a UF 6 recycle facility was developed which serves the purpose of stripping the UF 6 from the light auxiliary gas to be recycled in a separation nozzle cascade. The performance level achieved to date characterizes the separation nozzle process as reliable and feasible economically. Therefore, the erection of a separation nozzle demonstration plant can be recognized as the implementation of an enrichment process which combines a reliable and comparatively simple technology with a high potential for further improvements. (orig.) [de

  16. Padrões de distribuição volumétrica de pontas de pulverização de jato plano 11002, com e sem indução de ar, sob diferentes espaçamentos e alturas Distribution pattern of 11002 flat fan nozzles, with and without air induction, under different operational conditions

    Directory of Open Access Journals (Sweden)

    Fernando C. Bauer

    2006-08-01

    Full Text Available O presente trabalho teve como objetivo avaliar a distribuição volumétrica de pontas de pulverização hidráulica de jato de uso ampliado 11002, com e sem indução de ar, em laboratório, bem como o padrão de deposição da pulverização, por meio da estimativa do coeficiente de variação (C.V. obtido pela simulação da sobreposição de jatos adjacentes. As pontas foram posicionadas, isoladamente, no centro da mesa de teste, a 30; 40 e 50 cm de altura da mesa e a 300 e 500 kPa de pressão. Foram avaliadas 20 unidades de cada tipo de ponta, e a deposição média foi utilizada para a simulação da deposição ao longo da barra pulverizadora, com as pontas espaçadas em 30; 40; 50 e 60 cm entre si. A uniformidade da distribuição foi estimada pelo cálculo do C.V. resultante da simulação da sobreposição das pontas em barra de 8 m, sendo utilizados somente os 4 m centrais no cálculo do C.V. Os resultados mostraram haver diferenças relacionadas à deposição entre os dois tipos de ponta. A ponta com indução de ar resultou em área de deposição inferior à ponta sem indução de ar. Esse comportamento foi observado em todas as alturas da barra e nas duas pressões, podendo-se inferir que esse comportamento possa ser característico das pontas com indução de ar.The spray distribution and uniformity characteristics of 11002 flat fan nozzles type with and without air induction were evaluated in the present research. Twenty units of flat fan nozzles with and without air induction were tested in patternator table. Each one of the units was tested separately, at the 30; 40 and 50 cm above the patternator table and submitted to pressures of 300 and 500 kPa. The means of the colleted spray volume distribution of each nozzle type was evaluated and entered in a PC program. Based on the deposition patterns, distribution uniformity for nozzles spaced at 30; 40; 50 and 60 cm was simulated in PC Program. The distribution uniformity was

  17. Firefighter Nozzle Reaction

    DEFF Research Database (Denmark)

    Chin, Selena K.; Sunderland, Peter B.; Jomaas, Grunde

    2017-01-01

    to anchor forces, the hose becomes straight. The nozzle reaction is found to equal the jet momentum flow rate, and it does not change when an elbow connects the hose to the nozzle. A forward force must be exerted by a firefighter or another anchor that matches the forward force that the jet would exert...... on a perpendicular wall. Three reaction expressions are derived, allowing it to be determined in terms of hose diameter, jet diameter, flow rate, and static pressure upstream of the nozzle. The nozzle reaction predictions used by the fire service are 56% to 90% of those obtained here for typical firefighting hand......Nozzle reaction and hose tension are analyzed using conservation of fluid momentum and assuming steady, inviscid flow and a flexible hose in frictionless contact with the ground. An expression that is independent of the bend angle is derived for the hose tension. If this tension is exceeded owing...

  18. Computational Fluid Dynamics Simulation of Dual Bell Nozzle Film Cooling

    Science.gov (United States)

    Braman, Kalen; Garcia, Christian; Ruf, Joseph; Bui, Trong

    2015-01-01

    Marshall Space Flight Center (MSFC) and Armstrong Flight Research Center (AFRC) are working together to advance the technology readiness level (TRL) of the dual bell nozzle concept. Dual bell nozzles are a form of altitude compensating nozzle that consists of two connecting bell contours. At low altitude the nozzle flows fully in the first, relatively lower area ratio, nozzle. The nozzle flow separates from the wall at the inflection point which joins the two bell contours. This relatively low expansion results in higher nozzle efficiency during the low altitude portion of the launch. As ambient pressure decreases with increasing altitude, the nozzle flow will expand to fill the relatively large area ratio second nozzle. The larger area ratio of the second bell enables higher Isp during the high altitude and vacuum portions of the launch. Despite a long history of theoretical consideration and promise towards improving rocket performance, dual bell nozzles have yet to be developed for practical use and have seen only limited testing. One barrier to use of dual bell nozzles is the lack of control over the nozzle flow transition from the first bell to the second bell during operation. A method that this team is pursuing to enhance the controllability of the nozzle flow transition is manipulation of the film coolant that is injected near the inflection between the two bell contours. Computational fluid dynamics (CFD) analysis is being run to assess the degree of control over nozzle flow transition generated via manipulation of the film injection. A cold flow dual bell nozzle, without film coolant, was tested over a range of simulated altitudes in 2004 in MSFC's nozzle test facility. Both NASA centers have performed a series of simulations of that dual bell to validate their computational models. Those CFD results are compared to the experimental results within this paper. MSFC then proceeded to add film injection to the CFD grid of the dual bell nozzle. A series of

  19. Transition nozzle combustion system

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Won-Wook; McMahan, Kevin Weston; Maldonado, Jaime Javier

    2016-11-29

    The present application provides a combustion system for use with a cooling flow. The combustion system may include a head end, an aft end, a transition nozzle extending from the head end to the aft end, and an impingement sleeve surrounding the transition nozzle. The impingement sleeve may define a first cavity in communication with the head end for a first portion of the cooling flow and a second cavity in communication with the aft end for a second portion of the cooling flow. The transition nozzle may include a number of cooling holes thereon in communication with the second portion of the cooling flow.

  20. Study of nozzle deposit formation mechanism for direct injection gasoline engines; Chokufun gasoline engine yo nozzle no deposit seisei kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Kinoshita, M.; Saito, A. [Toyota Central Research and Development Labs., Inc., Aichi (Japan); Matsushita, S. [Toyota Motor Corp., Aichi (Japan); Shibata, H. [Nippon Soken, Inc., Tokyo (Japan); Niwa, Y. [Denso Corp., Aichi (Japan)

    1997-10-01

    Nozzles in fuel injectors for direct injection gasoline engines are exposed to high temperature combustion gases and soot. In such a rigorous environment, it is a fear that fuel flow rate changes in injectors by deposit formation on nozzles. Fundamental factors of nozzle deposit formation were investigated through injector bench tests and engine dynamometer tests. Deposit formation processes were observed by SEM through engine dynamometer tests. The investigation results reveal nozzle deposit formation mechanism and how to suppress the deposit. 4 refs., 8 figs., 3 tabs.

  1. Upper Stage Engine Composite Nozzle Extensions

    Science.gov (United States)

    Valentine, Peter G.; Allen, Lee R.; Gradl, Paul R.; Greene, Sandra E.; Sullivan, Brian J.; Weller, Leslie J.; Koenig, John R.; Cuneo, Jacques C.; Thompson, James; Brown, Aaron; hide

    2015-01-01

    Carbon-carbon (C-C) composite nozzle extensions are of interest for use on a variety of launch vehicle upper stage engines and in-space propulsion systems. The C-C nozzle extension technology and test capabilities being developed are intended to support National Aeronautics and Space Administration (NASA) and United States Air Force (USAF) requirements, as well as broader industry needs. Recent and on-going efforts at the Marshall Space Flight Center (MSFC) are aimed at both (a) further developing the technology and databases for nozzle extensions fabricated from specific CC materials, and (b) developing and demonstrating low-cost capabilities for testing composite nozzle extensions. At present, materials development work is concentrating on developing a database for lyocell-based C-C that can be used for upper stage engine nozzle extension design, modeling, and analysis efforts. Lyocell-based C-C behaves in a manner similar to rayon-based CC, but does not have the environmental issues associated with the use of rayon. Future work will also further investigate technology and database gaps and needs for more-established polyacrylonitrile- (PAN-) based C-C's. As a low-cost means of being able to rapidly test and screen nozzle extension materials and structures, MSFC has recently established and demonstrated a test rig at MSFC's Test Stand (TS) 115 for testing subscale nozzle extensions with 3.5-inch inside diameters at the attachment plane. Test durations of up to 120 seconds have been demonstrated using oxygen/hydrogen propellants. Other propellant combinations, including the use of hydrocarbon fuels, can be used if desired. Another test capability being developed will allow the testing of larger nozzle extensions (13.5- inch inside diameters at the attachment plane) in environments more similar to those of actual oxygen/hydrogen upper stage engines. Two C-C nozzle extensions (one lyocell-based, one PAN-based) have been fabricated for testing with the larger

  2. Technical Note: Validation of halo modeling for proton pencil beam spot scanning using a quality assurance test pattern

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Liyong, E-mail: linl@uphs.upenn.edu; Huang, Sheng; Kang, Minglei; Solberg, Timothy D.; McDonough, James E.; Ainsley, Christopher G. [Department of Radiation Oncology, University of Pennsylvania, 3400 Civic Center Boulevard, Philadelphia, Pennsylvania 19104 (United States)

    2015-09-15

    Purpose: The purpose of this paper is to demonstrate the utility of a comprehensive test pattern in validating calculation models that include the halo component (low-dose tails) of proton pencil beam scanning (PBS) spots. Such a pattern has been used previously for quality assurance purposes to assess spot shape, position, and dose. Methods: In this study, a scintillation detector was used to measure the test pattern in air at isocenter for two proton beam energies (115 and 225 MeV) of two IBA universal nozzles (UN #1 and UN #2). Planar measurements were compared with calculated dose distributions based on the weighted superposition of location-independent (UN #1) or location-dependent (UN #2) spot profiles, previously measured using a pair-magnification method and between two nozzles. Results: Including the halo component below 1% of the central dose is shown to improve the gamma-map comparison between calculation and measurement from 94.9% to 98.4% using 2 mm/2% criteria for the 115 MeV proton beam of UN #1. In contrast, including the halo component below 1% of the central dose does not improve the gamma agreement for the 115 MeV proton beam of UN #2, due to the cutoff of the halo component at off-axis locations. When location-dependent spot profiles are used for calculation instead of spot profiles at central axis, the gamma agreement is improved from 98.0% to 99.5% using 2 mm/2% criteria. The two nozzles clearly have different characteristics, as a direct comparison of measured data shows a passing rate of 89.7% for the 115 MeV proton beam. At 225 MeV, the corresponding gamma comparisons agree better between measurement and calculation, and between measurements in the two nozzles. Conclusions: In addition to confirming the primary component of individual PBS spot profiles, a comprehensive test pattern is useful for the validation of the halo component at off-axis locations, especially for low energy protons.

  3. A new multiple channel data recording system for mechanised ultrasonic testing of pipes and nozzles by A-scan processing

    International Nuclear Information System (INIS)

    Heumueller, R.; Rathgeb, W.; Szafarska, E.; Bertus, N.; Erhard, A.; Montag, H.J.; Wuestenberg, H.

    1989-01-01

    A system of equipment for ultrasonic testing in nuclear technique is introduced. This is a four channel ultrasonic equipment, which consists of a manipulator suitable for components, up to four conventional test heads, a test head connection box connected with them via 20 metres of coaxial cable, a documentation unit for signal detection and conversion, a data collection computer for parametricising the equipment, measurement display and representation and a disc memory. The advantages of this test system lie in its easy use because of the compact equipment dimensions, in the data collection of the complete A picture by the documentation unit and in the flexible evaluation of the collected data by the computer. (MM) [de

  4. Turbofan Noise Reduction Associated With Increased Bypass Nozzle Flow

    Science.gov (United States)

    Woodward, Richard P.; Hughes, Christopher E.

    2005-01-01

    An advanced 22-in. scale model turbofan, typical of a current-generation aircraft engine design by GE Aircraft Engines, was tested in NASA Glenn Research Center s 9- by 15- Foot Low-Speed Wind Tunnel to explore the far-field acoustic effects of an increased bypass nozzle area at simulated aircraft speeds of takeoff, approach, and landing. The wind-tunnel-scale model consisted of the bypass stage fan, stators, and nacelle (including the fan exit nozzle) of a typical turbofan. This fan-stage test was part of the NASA Glenn Fan Broadband Source Diagnostic Test, second entry, which acquired aeroacoustic results over a range of test conditions. A baseline nozzle was selected, and the nozzle area was chosen for maximum performance at sea-level conditions. Two additional nozzles were also tested--one with a 5.4-percent increase in nozzle area over the baseline nozzle (sized for design point conditions), corresponding to a 5-percent increase in fan weight flow, and another nozzle with a 10.9-percent increase in nozzle area over the baseline nozzle (sized for maximum weight flow at sea-level conditions), corresponding to a 7.5 percent increase in fan weight flow. Measured acoustic benefits with increased nozzle area were very encouraging, showing overall sound power level reductions of 2 dB or more (left graph) while the stage adiabatic efficiency (right graph) and thrust (final graph) actually increased by several percentage points. These noise-reduction benefits were seen to include both rotor-interaction tones and broadband noise, and were evident throughout the range of measured sideline angles.

  5. 21 CFR 892.1420 - Radionuclide test pattern phantom.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radionuclide test pattern phantom. 892.1420... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1420 Radionuclide test pattern phantom. (a) Identification. A radionuclide test pattern phantom is a device that consists of an arrangement...

  6. Aeroelastic Modeling of a Nozzle Startup Transient

    Science.gov (United States)

    Wang, Ten-See; Zhao, Xiang; Zhang, Sijun; Chen, Yen-Sen

    2014-01-01

    Lateral nozzle forces are known to cause severe structural damage to any new rocket engine in development during test. While three-dimensional, transient, turbulent, chemically reacting computational fluid dynamics methodology has been demonstrated to capture major side load physics with rigid nozzles, hot-fire tests often show nozzle structure deformation during major side load events, leading to structural damages if structural strengthening measures were not taken. The modeling picture is incomplete without the capability to address the two-way responses between the structure and fluid. The objective of this study is to develop a tightly coupled aeroelastic modeling algorithm by implementing the necessary structural dynamics component into an anchored computational fluid dynamics methodology. The computational fluid dynamics component is based on an unstructured-grid, pressure-based computational fluid dynamics formulation, while the computational structural dynamics component is developed under the framework of modal analysis. Transient aeroelastic nozzle startup analyses at sea level were performed, and the computed transient nozzle fluid-structure interaction physics presented,

  7. Field application of phased array ultrasonic testing for structural weld overlay on dissimilar welds of pressurizer nozzles

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Hoi; Kim, Yong Sik [Korea Hydro and Nuclear Power Company Ltd., Central Research Institute, Daejeon (Korea, Republic of)

    2015-08-15

    Weld overlay was first used in power plants in the US in the early 1980s as an interim method of repairing the welds of flawed piping joints. Weld overlaid piping joints in nuclear power plants must be examined periodically using ultrasonic examination technology. Portable phased array ultrasonic technology has recently become available. Currently, the application of preemptive weld overlays as a mitigation technique and/as a method to improve the examination surface condition for more complex configurations is becoming more common. These complex geometries may require several focused conventional transducers for adequate inspection of the overlay, the original weld, and the base material. Alternatively, Phased array ultrasonic probes can be used to generate several inspection angles simultaneously at various focal depths to provide better and faster coverage than that possible by conventional methods. Thus, this technology can increase the speed of examinations, save costs, and reduce radiation exposure. In this paper, we explain the general sequence of the inspection of weld overlay and the results of signal analysis for some PAUT (phased array ultrasonic testing) signals detected in on-site inspections.

  8. Advanced Solid Rocket Motor nozzle development status

    Science.gov (United States)

    Kearney, W. J.; Moss, J. D.

    1993-01-01

    This paper presents a status update of the design and development of an improved nozzle for the Advanced Solid Rocket Motor (ASRM). The ASRM nozzle incorporates advanced state-of-the-art design features and materials which contribute to enhanced safety, reliability, performance, and producibility for the space shuttle boosters. During 1992 the nozzle design progressed through a successful Preliminary Design Review (PDR). An improved ablative material development program also culminated in the selection of new standard and low density carbon cloth phenolic prepreg offering reduced variability and improved process attributes. A subscale motor test series to evaluate new materials and design features was also completed. An overview update of the matured design characteristics, supporting analysis, key development-program results and program status and plans is reported.

  9. Noise from Aft Deck Exhaust Nozzles: Differences in Experimental Embodiments

    Science.gov (United States)

    Bridges, James E.

    2014-01-01

    Two embodiments of a rectangular nozzle on an aft deck are compared. In one embodiment the lower lip of the nozzle was extended with the sidewalls becoming triangles. In a second embodiment a rectangular nozzle was fitted with a surface that fit flush to the lower lip and extended outward from the sides of the nozzle, approximating a semi-infinite plane. For the purpose of scale-model testing, making the aft deck an integral part of the nozzle is possible for relatively short deck lengths, but a separate plate model is more flexible, accounts for the expanse of deck to the sides of the nozzle, and allows the nozzle to stand off from the deck. Both embodiments were tested and acoustic far-field results were compared. In both embodiments the extended deck introduces a new noise source, but the amplitude of the new source was dependent upon the span (cross-stream dimension) of the aft deck. The noise increased with deck length (streamwise dimension), and in the case of the beveled nozzle it increased with increasing aspect ratio. In previous studies of slot jets in wings it was noted that the increased noise from the extended aft deck appears as a dipole at the aft deck trailing edge, an acoustic source type with different dependence on velocity than jet mixing noise. The extraneous noise produced by the aft deck in the present studies also shows this behavior both in directivity and in velocity scaling.

  10. Premixed direct injection nozzle

    Science.gov (United States)

    Zuo, Baifang [Simpsonville, SC; Johnson, Thomas Edward [Greer, SC; Lacy, Benjamin Paul [Greer, SC; Ziminsky, Willy Steve [Simpsonville, SC

    2011-02-15

    An injection nozzle having a main body portion with an outer peripheral wall is disclosed. The nozzle includes a plurality of fuel/air mixing tubes disposed within the main body portion and a fuel flow passage fluidly connected to the plurality of fuel/air mixing tubes. Fuel and air are partially premixed inside the plurality of the tubes. A second body portion, having an outer peripheral wall extending between a first end and an opposite second end, is connected to the main body portion. The partially premixed fuel and air mixture from the first body portion gets further mixed inside the second body portion. The second body portion converges from the first end toward said second end. The second body portion also includes cooling passages that extend along all the walls around the second body to provide thermal damage resistance for occasional flame flash back into the second body.

  11. Limit loads in nozzles

    International Nuclear Information System (INIS)

    Zouain, N.

    1983-01-01

    The static method for the evaluation of the limit loads of a perfectly elasto-plastic structure is presented. Using the static theorem of Limit Analysis and the Finite Element Method, a lower bound for the colapso load can be obtained through a linear programming problem. This formulation if then applied to symmetrically loaded shells of revolution and some numerical results of limit loads in nozzles are also presented. (Author) [pt

  12. The fabrication of nozzles for nuclear components by welding

    International Nuclear Information System (INIS)

    Moraes, M.M.; Krausser, P.; Echeverria, J.A.V.

    1986-01-01

    A nozzle with medium outside diameter of 1000 mm and medium thickness of 150 mm composed integrally by deposited metal by submerged-arc (wire S3NiMo1, 0.5mm) was fabricated in NUCLEP. The nondestructive, mechanical, metallographic and chemical testing carried out in a test sample made by the same procedure and welding parameters, showed results according to specifications established for primary components for nuclear power plants, and the tests presented mechanical properties and tenacity better than similar nozzle samples. This nozzle is cheapest concerning to importations, in respecting to its forged similar. (M.C.K.) [pt

  13. Noise of Embedded High Aspect Ratio Nozzles

    Science.gov (United States)

    Bridges, James E.

    2011-01-01

    A family of high aspect ratio nozzles were designed to provide a parametric database of canonical embedded propulsion concepts. Nozzle throat geometries with aspect ratios of 2:1, 4:1, and 8:1 were chosen, all with convergent nozzle areas. The transition from the typical round duct to the rectangular nozzle was designed very carefully to produce a flow at the nozzle exit that was uniform and free from swirl. Once the basic rectangular nozzles were designed, external features common to embedded propulsion systems were added: extended lower lip (a.k.a. bevel, aft deck), differing sidewalls, and chevrons. For the latter detailed Reynolds-averaged Navier-Stokes (RANS) computational fluid dynamics (CFD) simulations were made to predict the thrust performance and to optimize parameters such as bevel length, and chevron penetration and azimuthal curvature. Seventeen of these nozzles were fabricated at a scale providing a 2.13 inch diameter equivalent area throat." ! The seventeen nozzles were tested for far-field noise and a few data were presented here on the effect of aspect ratio, bevel length, and chevron count and penetration. The sound field of the 2:1 aspect ratio rectangular jet was very nearly axisymmetric, but the 4:1 and 8:1 were not, the noise on their minor axes being louder than the major axes. Adding bevel length increased the noise of these nozzles, especially on their minor axes, both toward the long and short sides of the beveled nozzle. Chevrons were only added to the 2:1 rectangular jet. Adding 4 chevrons per wide side produced some decrease at aft angles, but increased the high frequency noise at right angles to the jet flow. This trend increased with increasing chevron penetration. Doubling the number of chevrons while maintaining their penetration decreased these effects. Empirical models of the parametric effect of these nozzles were constructed and quantify the trends stated above." Because it is the objective of the Supersonics Project that

  14. SU-E-T-239: Monte Carlo Modelling of SMC Proton Nozzles Using TOPAS

    International Nuclear Information System (INIS)

    Chung, K; Kim, J; Shin, J; Han, Y; Ju, S; Hong, C; Kim, D; Kim, H; Shin, E; Ahn, S; Chung, S; Choi, D

    2014-01-01

    Purpose: To expedite and cross-check the commissioning of the proton therapy nozzles at Samsung Medical Center using TOPAS. Methods: We have two different types of nozzles at Samsung Medical Center (SMC), a multi-purpose nozzle and a pencil beam scanning dedicated nozzle. Both nozzles have been modelled in Monte Carlo simulation by using TOPAS based on the vendor-provided geometry. The multi-purpose nozzle is mainly composed of wobbling magnets, scatterers, ridge filters and multi-leaf collimators (MLC). Including patient specific apertures and compensators, all the parts of the nozzle have been implemented in TOPAS following the geometry information from the vendor.The dedicated scanning nozzle has a simpler structure than the multi-purpose nozzle with a vacuum pipe at the down stream of the nozzle.A simple water tank volume has been implemented to measure the dosimetric characteristics of proton beams from the nozzles. Results: We have simulated the two proton beam nozzles at SMC. Two different ridge filters have been tested for the spread-out Bragg peak (SOBP) generation of wobbling mode in the multi-purpose nozzle. The spot sizes and lateral penumbra in two nozzles have been simulated and analyzed using a double Gaussian model. Using parallel geometry, both the depth dose curve and dose profile have been measured simultaneously. Conclusion: The proton therapy nozzles at SMC have been successfully modelled in Monte Carlo simulation using TOPAS. We will perform a validation with measured base data and then use the MC simulation to interpolate/extrapolate the measured data. We believe it will expedite the commissioning process of the proton therapy nozzles at SMC

  15. Fuel nozzle tube retention

    Energy Technology Data Exchange (ETDEWEB)

    Cihlar, David William; Melton, Patrick Benedict

    2017-02-28

    A system for retaining a fuel nozzle premix tube includes a retention plate and a premix tube which extends downstream from an outlet of a premix passage defined along an aft side of a fuel plenum body. The premix tube includes an inlet end and a spring support feature which is disposed proximate to the inlet end. The premix tube extends through the retention plate. The spring retention feature is disposed between an aft side of the fuel plenum and the retention plate. The system further includes a spring which extends between the spring retention feature and the retention plate.

  16. Novel design for transparent high-pressure fuel injector nozzles

    Science.gov (United States)

    Falgout, Z.; Linne, M.

    2016-08-01

    The efficiency and emissions of internal combustion (IC) engines are closely tied to the formation of the combustible air-fuel mixture. Direct-injection engines have become more common due to their increased practical flexibility and efficiency, and sprays dominate mixture formation in these engines. Spray formation, or rather the transition from a cylindrical liquid jet to a field of isolated droplets, is not completely understood. However, it is known that nozzle orifice flow and cavitation have an important effect on the formation of fuel injector sprays, even if the exact details of this effect remain unknown. A number of studies in recent years have used injectors with optically transparent nozzles (OTN) to allow observation of the nozzle orifice flow. Our goal in this work is to design various OTN concepts that mimic the flow inside commercial injector nozzles, at realistic fuel pressures, and yet still allow access to the very near nozzle region of the spray so that interior flow structure can be correlated with primary breakup dynamics. This goal has not been achieved until now because interior structures can be very complex, and the most appropriate optical materials are brittle and easily fractured by realistic fuel pressures. An OTN design that achieves realistic injection pressures and grants visual access to the interior flow and spray formation will be explained in detail. The design uses an acrylic nozzle, which is ideal for imaging the interior flow. This nozzle is supported from the outside with sapphire clamps, which reduces tensile stresses in the nozzle and increases the nozzle's injection pressure capacity. An ensemble of nozzles were mechanically tested to prove this design concept.

  17. Effects of dimensional size and surface roughness on service performance for a micro Laval nozzle

    Science.gov (United States)

    Cai, Yukui; Liu, Zhanqiang; Shi, Zhenyu

    2017-05-01

    Nozzles with large and small dimensions are widely used in various industries. The main objective of this research is to investigate the effects of dimensional size and surface roughness on the service performance of a micro Laval nozzle. The variation of nozzle service performance from the conventional macro to micro scale is presented in this paper. This shows that the dimensional nozzle size has a serious effect on the nozzle gas flow friction. With the decrease of nozzle size, the velocity performance and thrust performance deteriorate. The micro nozzle performance has less sensitivity to the variation of surface roughness than the large scale nozzle does. Surface quality improvement and burr prevention technologies are proposed to reduce the friction effect on the micro nozzle performance. A novel process is then developed to control and depress the burr generation during micro nozzle machining. The polymethyl-methacrylate as a coating material is coated on the rough machined surface before finish machining. Finally, the micro nozzle with a throat diameter of 1 mm is machined successfully. Thrust test results show that the implement and application of this machining process benefit the service performance improvement of the micro nozzle.

  18. Effects of dimensional size and surface roughness on service performance for a micro Laval nozzle

    International Nuclear Information System (INIS)

    Cai, Yukui; Liu, Zhanqiang; Shi, Zhenyu

    2017-01-01

    Nozzles with large and small dimensions are widely used in various industries. The main objective of this research is to investigate the effects of dimensional size and surface roughness on the service performance of a micro Laval nozzle. The variation of nozzle service performance from the conventional macro to micro scale is presented in this paper. This shows that the dimensional nozzle size has a serious effect on the nozzle gas flow friction. With the decrease of nozzle size, the velocity performance and thrust performance deteriorate. The micro nozzle performance has less sensitivity to the variation of surface roughness than the large scale nozzle does. Surface quality improvement and burr prevention technologies are proposed to reduce the friction effect on the micro nozzle performance. A novel process is then developed to control and depress the burr generation during micro nozzle machining. The polymethyl-methacrylate as a coating material is coated on the rough machined surface before finish machining. Finally, the micro nozzle with a throat diameter of 1 mm is machined successfully. Thrust test results show that the implement and application of this machining process benefit the service performance improvement of the micro nozzle. (paper)

  19. Influence study of flow separation on the nozzle vibration response

    Directory of Open Access Journals (Sweden)

    Geng Li

    2016-06-01

    Full Text Available In the present paper, the vibration response difference of the upper stage nozzle with higher expansion ratio between ground and altitude simulation hot-firing test is analyzed. It indicates that the acceleration response of the nozzle under ground hot-firing test is much higher than that of the altitude condition. In order to find the essential reason, the experimental and numerical simulation studies of the flow separation are developed by using the test engine nozzle. The experimental data show that the nozzle internal flow occurred flow separation and the divergence cone internal wall pressure pulsation increased significantly downstream from the separation location. The numerical simulation and experimental results indicate that the increase of internal wall pressure and turbulence pulsating pressure are the substantial reason of vibration response increasing aggravatingly during the ground firing test.

  20. Optimal Thrust Vectoring for an Annular Aerospike Nozzle, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Recent success of an annular aerospike flight test by NASA Dryden has prompted keen interest in providing thrust vector capability to the annular aerospike nozzle...

  1. Optimal Thrust Vectoring for an Annular Aerospike Nozzle Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Recent success of an annular aerospike flight test by NASA Dryden has prompted keen interest in providing thrust vector capability to the annular aerospike nozzle...

  2. Optimal Thrust Vectoring for an Annular Aerospike Nozzle, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Recent success of an annular aerospike flight test by NASA Dryden has prompted keen interest in providing thrust vector capability to the annular aerospike nozzle...

  3. Design criteria for piping and nozzles program

    International Nuclear Information System (INIS)

    Moore, S.E.; Bryson, J.W.

    1977-01-01

    This report reviews the activities and accomplishments of the Design Criteria for Piping and Nozzles program being conducted by the Oak Ridge National Laboratory for the period July 1, 1975, to September 30, 1976. The objectives of the program are to conduct integrated experimental and analytical stress analysis studies of piping system components and isolated and closely-spaced pressure vessel nozzles in order to confirm and/or improve the adequacy of structural design criteria and analytical methods used to assure the safe design of nuclear power plants. Activities this year included the development of a finite-element program for analyzing two closely spaced nozzles in a cylindrical pressure vessel; a limited-parameter study of vessels with isolated nozzles, finite-element studies of piping elbows, a fatigue test of an out-of-round elbow, summary and evaluation of experimental studies on the elastic-response and fatigue failure of tees, parameter studies on the behavior of flanged joints, publication of fifteen topical reports and papers on various experimental and analytical studies; and the development and acceptance of a number of design rules changes to the ASME Code. 2 figures, 2 tables

  4. Electrophoresis test prevalence, requesting patterns, yield and ...

    African Journals Online (AJOL)

    Most of the appropriate SPE test requests were from clinical haematology ... 1 Division of Chemical Pathology, Department of Pathology, National Health Laboratory Service and Faculty of Medicine and Health Sciences,. Stellenbosch ... electrophoresis (IFE)) in a South African (SA) pathology laboratory setting are limited.

  5. Hydrogen/Air Fuel Nozzle Emissions Experiments

    Science.gov (United States)

    Smith, Timothy D.

    2001-01-01

    The use of hydrogen combustion for aircraft gas turbine engines provides significant opportunities to reduce harmful exhaust emissions. Hydrogen has many advantages (no CO2 production, high reaction rates, high heating value, and future availability), along with some disadvantages (high current cost of production and storage, high volume per BTU, and an unknown safety profile when in wide use). One of the primary reasons for switching to hydrogen is the elimination of CO2 emissions. Also, with hydrogen, design challenges such as fuel coking in the fuel nozzle and particulate emissions are no longer an issue. However, because it takes place at high temperatures, hydrogen-air combustion can still produce significant levels of NOx emissions. Much of the current research into conventional hydrocarbon-fueled aircraft gas turbine combustors is focused on NOx reduction methods. The Zero CO2 Emission Technology (ZCET) hydrogen combustion project will focus on meeting the Office of Aerospace Technology goal 2 within pillar one for Global Civil Aviation reducing the emissions of future aircraft by a factor of 3 within 10 years and by a factor of 5 within 25 years. Recent advances in hydrocarbon-based gas turbine combustion components have expanded the horizons for fuel nozzle development. Both new fluid designs and manufacturing technologies have led to the development of fuel nozzles that significantly reduce aircraft emissions. The goal of the ZCET program is to mesh the current technology of Lean Direct Injection and rocket injectors to provide quick mixing, low emissions, and high-performance fuel nozzle designs. An experimental program is planned to investigate the fuel nozzle concepts in a flametube test rig. Currently, a hydrogen system is being installed in cell 23 at NASA Glenn Research Center's Research Combustion Laboratory. Testing will be conducted on a variety of fuel nozzle concepts up to combustion pressures of 350 psia and inlet air temperatures of 1200 F

  6. Experimental and numerical investigation of the cap-shock structure in over expanded thrust-optimized nozzles

    Energy Technology Data Exchange (ETDEWEB)

    Reijasse, P.; Bouvier, F.; Servel, P.

    2002-07-01

    This paper deals with the aerodynamics of an over-expanded nozzle, when the internal parabolic contour of the nozzle extension is highly thrust-optimized in terms of specific impulse-to-weight ratio. This optimization leads to an internal focusing shock issuing from a little downstream from the throat, even when the nozzle is running at nearly vacuum conditions. When such a nozzle is over-expanded, the focusing shock thus interferes with the over-expansion shock, and it forms from this shock interference a particular shock system, named 'cap-shock' because of the cap-like luminous shape seen in the over-expanded plumes of some real engines. Navier-Stokes calcinations performed in Europe had permitted to numerically analyze such a flow pattern, and they have revealed notably a recirculation bubble on the centerline downstream of the Mach disk, which had never been measured yet. A test campaign characterizing the flow separation in over-expanded sub-scale nozzles has been performed in the R2Ch blowdown wind tunnel of the Onera Chalais-Meudon center. Schlieren photographs of the exhaust jet have authorized a detailed description of the cap-shock pattern. Two-components Laser Doppler Velocimetry measurements have confirmed the existence of a recirculation bubble surrounded by an annular supersonic jet and has given its size. In addition to the calculations and the Schlieren interpretative sketches, these first quantitative experimental characterization of the cap-shock structure permit to state a physical description of the cap-shock induced flow field in the thrust-optimized nozzles. (authors)

  7. Automatic test pattern generation for iterative logic arrays | Boateng ...

    African Journals Online (AJOL)

    test are first formulated. Next, the repetition property of the test patterns is exploited to develop a method for generating C-tests for ILAs under the cell fault model. Based on the results of test generation, the method identifies points of insertion of ...

  8. The linear VGA nozzle - a versatile tool for coal utilization

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, W.A. Jr. [VGA Nozzle Co., Manchester, NH (United States)

    1993-12-31

    The newly available VGA nozzles provide significant improvements in a number of services and can advance the utilization of coal fuel in power plants and industrial processes. The nozzle designs for applications such as coal-water slurry combustion, flue gas cleaning, reburning and hot gas cooling, are described. VGA nozzles are patented as {open_quotes}Variable Gas Atomization,{close_quotes}. A conical configuration was first developed and successfully tested with heavy oil and coal-water mixture fuels at the Technical University of Nova Scotia. The test results showed the VGA nozzle to provide superior combustion characteristics at flow rates in excess of 1 gpm. The carbon burnout was complete, the total particulate emission was only 25% of that of competing nozzles, and there was a complete absence of wear of the nozzle tip and body components. A review is given of the 1980`s laboratory and field development/demonstration work and droplet particle size testing, previously reported at coal-slurry combustion and gas turbine conferences. Subsequently, a two phase S.B.I.R. (Small Business Innovative Research) program sponsored by DOE was recently completed by ADA Technologies, Inc., Englewood, CO, in which a production prototype linear VGA nozzle was developed for in-duct humidification of flue gases. As reported at the 1991 SO{sub 3} Control Symposium, December 3-6, Washington, DC, the nozzle achieves a 50% reduction in the energy consumption and lower capital, operating and maintenance costs. It is currently planned to market the linear VGA humidification nozzle as a cost-effective alternative to SO{sub 3} injection, for the conditioning of flue gas to achieve improved ESP performance.

  9. Design and Checkout of a High Speed Research Nozzle Evaluation Rig

    Science.gov (United States)

    Castner, Raymond S.; Wolter, John D.

    1997-01-01

    The High Flow Jet Exit Rig (HFJER) was designed to provide simulated mixed flow turbojet engine exhaust for one- seventh scale models of advanced High Speed Research test nozzles. The new rig was designed to be used at NASA Lewis Research Center in the Nozzle Acoustic Test Rig and the 8x6 Supersonic Wind Tunnel. Capabilities were also designed to collect nozzle thrust measurement, aerodynamic measurements, and acoustic measurements when installed at the Nozzle Acoustic Test Rig. Simulated engine exhaust can be supplied from a high pressure air source at 33 pounds of air per second at 530 degrees Rankine and nozzle pressure ratios of 4.0. In addition, a combustion unit was designed from a J-58 aircraft engine burner to provide 20 pounds of air per second at 2000 degrees Rankine, also at nozzle pressure ratios of 4.0. These airflow capacities were designed to test High Speed Research nozzles with exhaust areas from eighteen square inches to twenty-two square inches. Nozzle inlet flow measurement is available through pressure and temperature sensors installed in the rig. Research instrumentation on High Speed Research nozzles is available with a maximum of 200 individual pressure and 100 individual temperature measurements. Checkout testing was performed in May 1997 with a 22 square inch ASME long radius flow nozzle. Checkout test results will be summarized and compared to the stated design goals.

  10. Design and performance of atomizing nozzles for spray calcination of high-level wastes

    International Nuclear Information System (INIS)

    Miller, F.A.; Stout, L.A.

    1981-05-01

    A key aspect of high-level liquid-waste spray calcination is waste-feed atomization by using air atomizing nozzles. Atomization substantially increases the heat transfer area of the waste solution, which enhances rapid drying. Experience from the spray-calciner operations has demonstrated that nozzle flow conditions that produce 70-μ median-volume-diameter or smaller spray droplets are required for small-scale spray calciners (drying capacity less than 80 L/h). For large-scale calciners (drying capacity greater than 300 L/h), nozzle flow conditions that produce 100-μ median-volume-diameter or smaller spray droplets are required. Mass flow ratios of 0.2 to 0.4, depending on nozzle size, are required for proper operation of internal-mix atomizing nozzles. Both internal-mix and external-mix nozzles have been tested at PNL. Due to the lower airflow requirements and fewer large droplets produced, the internal-mix nozzle has been chosen for primary development in the spray calciner program at PNL. Several nozzle air-cap materials for internal-mix nozzles have been tested for wear resistance. Results show that nozzle air caps of stainless steel and Cer-vit (a machineable glass ceramic) are suceptible to rapid wear by abrasive slurries, whereas air caps of alumina and reaction-bonded silicon nitride show only slow wear. Longer-term testing is necessary to determine more accurately the actual frequency of nozzle replacement. Atomizing nozzle air caps of alumina are subject to fracture from thermal shock, whereas air caps of silicon nitride and Cer-vit are not. Fractured nozzles are held in place by the air-cap retaining ring and continue to atomize satisfactorily. Therefore, fractures caused by thermal shocking do not necessarily result in nozzle failure

  11. Wormhole Formation in RSRM Nozzle Joint Backfill

    Science.gov (United States)

    Stevens, J.

    2000-01-01

    The RSRM nozzle uses a barrier of RTV rubber upstream of the nozzle O-ring seals. Post flight inspection of the RSRM nozzle continues to reveal occurrence of "wormholes" into the RTV backfill. The term "wormholes", sometimes called "gas paths", indicates a gas flow path not caused by pre-existing voids, but by a little-understood internal failure mode of the material during motor operation. Fundamental understanding of the mechanics of the RSRM nozzle joints during motor operation, nonlinear viscoelastic characterization of the RTV backfill material, identification of the conditions that predispose the RTV to form wormholes, and screening of candidate replacement materials is being pursued by a joint effort between Thiokol Propulsion, NASA, and the Army Propulsion & Structures Directorate at Redstone Arsenal. The performance of the RTV backfill in the joint is controlled by the joint environment. Joint movement, which applies a tension and shear load on the material, coupled with the introduction of high pressure gas in combination create an environment that exceeds the capability of the material to withstand the wormhole effect. Little data exists to evaluate why the material fails under the modeled joint conditions, so an effort to characterize and evaluate the material under these conditions was undertaken. Viscoelastic property data from characterization testing will anchor structural analysis models. Data over a range of temperatures, environmental pressures, and strain rates was used to develop a nonlinear viscoelastic model to predict material performance, develop criteria for replacement materials, and quantify material properties influencing wormhole growth. Three joint simulation analogs were developed to analyze and validate joint thermal barrier (backfill) material performance. Two exploratory tests focus on detection of wormhole failure under specific motor operating conditions. A "validation" test system provides data to "validate" computer models and

  12. Injection nozzle for a turbomachine

    Science.gov (United States)

    Uhm, Jong Ho; Johnson, Thomas Edward; Kim, Kwanwoo

    2012-09-11

    A turbomachine includes a compressor, a combustor operatively connected to the compressor, an end cover mounted to the combustor, and an injection nozzle assembly operatively connected to the combustor. The injection nozzle assembly includes a first end portion that extends to a second end portion, and a plurality of tube elements provided at the second end portion. Each of the plurality of tube elements defining a fluid passage includes a body having a first end section that extends to a second end section. The second end section projects beyond the second end portion of the injection nozzle assembly.

  13. Injection and spray characteristics of a variable orifice nozzle applied the jerk type fuel injection pump for DI diesel engine; Jerk shiki nenryo funsha pump wo mochiita kahen funko nozzle no funsha funmu tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, T.; Matsui, K.; Iwasaki, T.; Kobayashi, T. [Zexel Corp., Tokyo (Japan); Matsumoto, Y. [The University of Tokyo, Tokyo (Japan)

    1997-10-01

    A Variable Orifice Nozzle (VON) by changing a cross-sectional area of the nozzle injection hole, for improving a rate of injection and injection duration, has been developed to study its injection and spray characteristics. The nozzle geometry was optimized to analyze a nozzle internal flow by computational method. Results show that, injection and spray pattern responded to the nozzle orifice cross-sectional area which is changing larger to smaller in the part load range. This results suggest to contribute a combustion improvement which decreasing NOx and soot. 14 refs., 10 figs.

  14. Marangoni flow on an inkjet nozzle plate

    NARCIS (Netherlands)

    de Jong, J.; Reinten, Hans; Wijshoff, H.; Wijshoff, Herman; van den Berg, Marc; Delescen, Koos; van Dongen, Rini; Mugele, Friedrich Gunther; Versluis, Michel; Lohse, Detlef

    2007-01-01

    In piezo inkjet printing, nozzle failures are often caused by an ink layer on the nozzle plate. It is experimentally shown that the ink layer at the nozzle is formed through streamers of ink, emanating from a central ink band on the nozzle plate. The streamers propagate over a wetting nanofilm of

  15. Fabrication, Cleaning, and Filtering of Microscopic Droplet Beam Nozzles

    Science.gov (United States)

    Warner, J.; Hunter, M.; Weierstall, U.; Spence, J. C. H.; Doak, R. B.

    2006-10-01

    Structure determination of proteins is a subject of intense current interest. Most relevant is a protein's native conformation, which generally requires it be immersed in water (if water-soluble) or a lipid jacket (if a membrane protein). Emerging schemes of serial protein diffraction propose to embed proteins in microscopic water droplets (membrane proteins encased in a detergent micelle) and pass these in vacuum through an x-ray or electron beam. Droplet diameters of tested, with and without sonication and both before and after the nozzle tip was formed. Flame burnishing was employed to smooth and clean the nozzles. In situ formation of silicate filter frits was investigated. Still, only about 30% of the 4 μm nozzles would run without clogging. An alternative to solid convergent nozzles will be described.

  16. Axisymmetric thrust-vectoring nozzle performance prediction

    International Nuclear Information System (INIS)

    Wilson, E. A.; Adler, D.; Bar-Yoseph, P.Z

    1998-01-01

    Throat-hinged geometrically variable converging-diverging thrust-vectoring nozzles directly affect the jet flow geometry and rotation angle at the nozzle exit as a function of the nozzle geometry, the nozzle pressure ratio and flight velocity. The consideration of nozzle divergence in the effective-geometric nozzle relation is theoretically considered here for the first time. In this study, an explicit calculation procedure is presented as a function of nozzle geometry at constant nozzle pressure ratio, zero velocity and altitude, and compared with experimental results in a civil thrust-vectoring scenario. This procedure may be used in dynamic thrust-vectoring nozzle design performance predictions or analysis for civil and military nozzles as well as in the definition of initial jet flow conditions in future numerical VSTOL/TV jet performance studies

  17. High Quality Test Pattern Generation and Boolean Satisfiability

    CERN Document Server

    Eggersglüß, Stephan

    2012-01-01

    This book provides an overview of automatic test pattern generation (ATPG) and introduces novel techniques to complement classical ATPG, based on Boolean Satisfiability (SAT).  A fast and highly fault efficient SAT-based ATPG framework is presented which is also able to generate high-quality delay tests such as robust path delay tests, as well as tests with long propagation paths to detect small delay defects. The aim of the techniques and methodologies presented in this book is to improve SAT-based ATPG, in order to make it applicable in industrial practice. Readers will learn to improve the performance and robustness of the overall test generation process, so that the ATPG algorithm reliably will generate test patterns for most targeted faults in acceptable run time to meet the high fault coverage demands of industry. The techniques and improvements presented in this book provide the following advantages: Provides a comprehensive introduction to test generation and Boolean Satisfiability (SAT); Describes a...

  18. HIV Testing Patterns among Urban YMSM of Color

    Science.gov (United States)

    Leonard, Noelle R.; Rajan, Sonali; Gwadz, Marya V.; Aregbesola, Temi

    2014-01-01

    The heightened level of risk for HIV infection among Black and Latino young men who have sex with men (YMSM) is driven by multilevel influences. Using cross-sectional data, we examined HIV testing patterns among urban YMSM of color in a high-HIV seroprevalence area (ages 16 to 21 years). Self-reported frequency of testing was high, with 42% of…

  19. Reactor pressure vessel nozzle

    Science.gov (United States)

    Challberg, Roy C.; Upton, Hubert A.

    1994-01-01

    A nozzle for joining a pool of water to a nuclear reactor pressure vessel includes a tubular body having a proximal end joinable to the pressure vessel and a distal end joinable in flow communication with the pool. The body includes a flow passage therethrough having in serial flow communication a first port at the distal end, a throat spaced axially from the first port, a conical channel extending axially from the throat, and a second port at the proximal end which is joinable in flow communication with the pressure vessel. The inner diameter of the flow passage decreases from the first port to the throat and then increases along the conical channel to the second port. In this way, the conical channel acts as a diverging channel or diffuser in the forward flow direction from the first port to the second port for recovering pressure due to the flow restriction provided by the throat. In the backflow direction from the second port to the first port, the conical channel is a converging channel and with the abrupt increase in flow area from the throat to the first port collectively increase resistance to flow therethrough.

  20. Performance and wear characteristics of ceramic, cemented carbide, and metal nozzles used in coal-water-slurry boilers

    Energy Technology Data Exchange (ETDEWEB)

    Deng, J.X.; Ding, Z.L.; Zhou, H.M.; Tan, Y.Q. [Xiangtan University, Xiangtan (China). School of Mechanical Engineering

    2009-09-15

    Ceramics, cemented carbides, and metals were prepared to be used as nozzles in CWS boilers. CWS burning tests in a boiler with these nozzles were carried out. The erosion wear resistance of these nozzles was compared by determining their erosion rates and hole diameter variation. Results showed that the life of the ceramic nozzles is about 30 times high than that of the metal nozzles. The wear types at the nozzle wall surface differed in various positions. The nozzle center wall section suffers form abrasive impact under low impact angles, and the damage at the center wall mainly occurs by plowing and plastic deformation for metals, and by polishing action for carbides and ceramics. The primary wear mechanisms at the exit of ceramic nozzle exhibited thermal shock damage with chipping owing to the greater thermal stresses.

  1. Proposed Flight Research of a Dual-Bell Rocket Nozzle Using the NASA F-15 Airplane

    Science.gov (United States)

    Jones, Daniel S.; Bui, Trong T.; Ruf, Joseph H.

    2013-01-01

    For more than a half-century, several types of altitude-compensating rocket nozzles have been proposed and analyzed, but very few have been adequately tested in a relevant flight environment. One type of altitude-compensating nozzle is the dual-bell rocket nozzle, which was first introduced into literature in 1949. Despite the performance advantages that have been predicted, both analytically and through static test data, the dual-bell nozzle has still not been adequately tested in a relevant flight environment. This paper proposes a method for conducting testing and research with a dual-bell rocket nozzle in a flight environment. We propose to leverage the existing NASA F-15 airplane and Propulsion Flight Test Fixture as the flight testbed, with the dual-bell nozzle operating during captive-carried flights, and with the nozzle subjected to a local flow field similar to that of a launch vehicle. The primary objective of this effort is not only to advance the technology readiness level of the dual-bell nozzle, but also to gain a greater understanding of the nozzle mode transitional sensitivity to local flow-field effects, and to quantify the performance benefits with this technology. The predicted performance benefits are significant, and may result in reducing the cost of delivering payloads to low-Earth orbit.

  2. Testing the spatial significance of weed patterns in arable land using Mead's test

    NARCIS (Netherlands)

    Heijting, S.; Werf, van der W.; Kruijer, W.T.; Stein, A.

    2007-01-01

    There is a need in weed science for statistical tests for patchiness and spatial pattern. The objective of this study was to investigate the performance of Mead¿s test for detecting patterns in synthetic data and in real weed counts made in maize, and making a first assessment of its applicability

  3. Testing the spatial significance of weed patterns in arable land using Mead's test

    NARCIS (Netherlands)

    Heijting, S.; van der Werf, W.; Kruijer, W.T.; Stein, A.

    2007-01-01

    There is a need in weed science for statistical tests for patchiness and spatial pattern. The objective of this study was to investigate the performance of Mead's test for detecting patterns in synthetic data and in real weed counts made in maize, and making a first assessment of its applicability

  4. Experiments on black liquor splashplate nozzle performance

    Energy Technology Data Exchange (ETDEWEB)

    Nieminen, K.

    1996-12-31

    The performance of a throttled black liquor splashplate nozzle was studied in this work. A series of industrial-scale experiments were performed using mass flow rate as a variable at a fixed temperature. The experiments were carried out in a spraying chamber next to the recovery boiler with real mill liquor. The disintegration process of the liquor sheet was videotaped for analyzing. The mass flow rate distribution was measured with a collector. The liquor drops produced by the nozzle were videotaped and measured with a video image analysis technique. The industrial-scale experiments were afterwards repeated on a small scale in the laboratory environment which made it possible to study the liquid sheet disintegration process thoroughly. The small-scale experiments were carried out with a solution of water and glycerol and a splashplate nozzle of approximately one tenth the size of full-scale nozzle. The whole liquid sheet and close-up exposures of the plate area were videotaped. However, the videotaping equipment (camera and objective) were not capable of observing the very thin and transparent liquid sheet. The mass flow rate distribution was measured with steps of 2.5 deg from the plate centerline with a collector device. The drop sizes were measured from various sheet angles with Malvern Particle Sizer and a phase Doppler particle anemometer (Aerometrics). The modeling was based on dimensional analysis. The objective was to compare these two experimental settings and to find out whether small-scale experiments can be used in predicting the spraying characteristics in the full-scale. It was also of interest to test the measured black liquor drop sizes against drop size correlations obtained from the literature. (31 refs.)

  5. Analysis of film cooling in rocket nozzles

    Science.gov (United States)

    Woodbury, Keith A.

    1992-01-01

    Computational Fluid Dynamics (CFD) programs are customarily used to compute details of a flow field, such as velocity fields or species concentrations. Generally they are not used to determine the resulting conditions at a solid boundary such as wall shear stress or heat flux. However, determination of this information should be within the capability of a CFD code, as the code supposedly contains appropriate models for these wall conditions. Before such predictions from CFD analyses can be accepted, the credibility of the CFD codes upon which they are based must be established. This report details the progress made in constructing a CFD model to predict the heat transfer to the wall in a film cooled rocket nozzle. Specifically, the objective of this work is to use the NASA code FDNS to predict the heat transfer which will occur during the upcoming hot-firing of the Pratt & Whitney 40K subscale nozzle (1Q93). Toward this end, an M = 3 wall jet is considered, and the resulting heat transfer to the wall is computed. The values are compared against experimental data available in Reference 1. Also, FDNS's ability to compute heat flux in a reacting flow will be determined by comparing the code's predictions against calorimeter data from the hot firing of a 40K combustor. The process of modeling the flow of combusting gases through the Pratt & Whitney 40K subscale combustor and nozzle is outlined. What follows in this report is a brief description of the FDNS code, with special emphasis on how it handles solid wall boundary conditions. The test cases and some FDNS solution are presented next, along with comparison to experimental data. The process of modeling the flow through a chamber and a nozzle using the FDNS code will also be outlined.

  6. INVESTIGATION OF FLOW BEHAVIOR IN MINIMUM QUANTITY LUBRICATION NOZZLE FOR END MILLING PROCESSES

    Directory of Open Access Journals (Sweden)

    M.S. Najiha

    2012-12-01

    Full Text Available Minimum quantity lubrication (MQL is a sustainable manufacturing technique that has replaced conventional flooded lubrication methods and dry machining. In the MQL technique, the lubricant is sprayed onto the friction surfaces through nozzles through small pneumatically-operated pumps. This paper presents an investigation into the flow behavior of the lubricant and air mixture under certain pressures at the tip of a nozzle specially designed for MQL. The nozzle used is an MQL stainless steel nozzle, 6.35 mm in diameter. Computational fluid dynamics is used to determine the flow pattern at the tip of the nozzle where the lubricant and compressed air are mixed to form a mist. The lubricant volume flow is approximately 0.08 ml/cycle of the pump. A transient, pressure-based, three-dimensional analysis is performed with a viscous, realizable k-ε model. The results are obtained in the form of vector plots and flow fields. The flow mixing at the tip of the nozzle is wholly shown through the flow fields and vector plots. This study provides an insight into the flow distribution at the tip of the nozzle for a certain pressure to aid modifications in the design of the nozzle for future MQL studies. It attainable aids to determine the correct pressure for the air jet at the nozzle tip.

  7. Nozzle geometry for organic vapor jet printing

    Science.gov (United States)

    Forrest, Stephen R.; McGraw, Gregory

    2017-10-25

    A first device is provided. The device includes a print head. The print head further includes a first nozzle hermetically sealed to a first source of gas. The first nozzle has an aperture having a smallest dimension of 0.5 to 500 microns in a direction perpendicular to a flow direction of the first nozzle. At a distance from the aperture into the first nozzle that is 5 times the smallest dimension of the aperture of the first nozzle, the smallest dimension perpendicular to the flow direction is at least twice the smallest dimension of the aperture of the first nozzle.

  8. Pattern Of Skin Prick Allergy Test Results In Enugu | Mgbor ...

    African Journals Online (AJOL)

    In this study we report on pattern of allergy prick skin test results found among atopic patients attending the department of otorhinolargngology of the University of Nigeria Teaching Hospital Enugu and Hansa Clinics, Enugu and propose ways of minimizing the exposure of the population to allergens. Material and method

  9. A new hierachical approach to test-pattern generation

    NARCIS (Netherlands)

    Weening, E.C.; Weening, Edward C.; Kerkhoff, Hans G.

    1991-01-01

    The authors present a new and fully hierarchical approach to automatic test-pattern generation, for digital MOS VLSI circuits. The description of a VLSI circuit consists of several hierarchical levels of interconnected modules. Each module consists of one or more sub-modules are functionally

  10. Stress intensities for nozzle cracks in reactor vessels. Reporting period, January 1, 1976--October 31, 1976

    International Nuclear Information System (INIS)

    Smith, C.W.; Jolles, M.; Peters, W.H.

    1976-11-01

    A series of six frozen stress photoelastic tests was conducted to investigate the distribution of stress intensity factor (SIF) along a crack which occurred at the juncture of a pipe (nozzle) with a cylindrical pressure vessel. Typical photoelastic fringe patterns are shown for slices which were taken mutually orthogonal to the flaw border and the flaw surface. A typical plot of normalized apparent SIF versus square root of normalized distance from the crack tip is presented. The variation in SIF along the flaw border is given for all six different crack geometries and also the variation of SIF with varying a/T is presented. 40 references

  11. Conceptual Design for a Dual-Bell Rocket Nozzle System Using a NASA F-15 Airplane as the Flight Testbed

    Science.gov (United States)

    Jones, Daniel S.; Ruf, Joseph H.; Bui, Trong T.; Martinez, Martel; St. John, Clinton W.

    2014-01-01

    The dual-bell rocket nozzle was first proposed in 1949, offering a potential improvement in rocket nozzle performance over the conventional-bell nozzle. Despite the performance advantages that have been predicted, both analytically and through static test data, the dual-bell nozzle has still not been adequately tested in a relevant flight environment. In 2013 a proposal was constructed that offered a National Aeronautics and Space Administration (NASA) F-15 airplane as the flight testbed, with the plan to operate a dual-bell rocket nozzle during captive-carried flight. If implemented, this capability will permit nozzle operation into an external flow field similar to that of a launch vehicle, and facilitate an improved understanding of dual-bell nozzle plume sensitivity to external flow-field effects. More importantly, this flight testbed can be utilized to help quantify the performance benefit with the dual-bell nozzle, as well as to advance its technology readiness level. Toward this ultimate goal, this report provides plans for future flights to quantify the external flow field of the airplane near the nozzle experiment, as well as details on the conceptual design for the dual-bell nozzle cold-flow propellant feed system integration within the NASA F-15 Propulsion Flight Test Fixture. The current study shows that this concept of flight research is feasible, and could result in valuable flight data for the dual-bell nozzle.

  12. Thermal-Hydraulic Performance of Scrubbing Nozzle Used for CFVS

    International Nuclear Information System (INIS)

    Lee, Hyun Chul; Lee, Doo Yong; Jung, Woo Young; Lee, Jong Chan; Kim, Gyu Tae

    2016-01-01

    A Containment Filtered Venting System (CFVS) is the most interested device to mitigate a threat against containment integrity under the severe accident of nuclear power plant by venting with the filtration of the fission products. FNC technology and partners have been developed the self-priming scrubbing nozzle used for the CFVS which is based on the venturi effect. The thermal-hydraulic performances such as passive scrubbing water suction as well as pressure drop across the nozzle have been tested under various thermal-hydraulic conditions. The two types of test section have been built for testing the thermal-hydraulic performance of the self-priming scrubbing nozzle. Through the visualization loop, the liquid suction performance through the slit, pressure drop across the nozzle are measured. The passive water suction flow through the suction slit at the throat is important parameter to define the scrubbing performance of the self-priming scrubbing nozzle. The water suction flow is increased with the increase of the overhead water level at the same inlet gas flow. It is not so much changed with the change of inlet gas flow at the overhead water level.

  13. Prototype Morphing Fan Nozzle Demonstrated

    Science.gov (United States)

    Lee, Ho-Jun; Song, Gang-Bing

    2004-01-01

    Ongoing research in NASA Glenn Research Center's Structural Mechanics and Dynamics Branch to develop smart materials technologies for aeropropulsion structural components has resulted in the design of the prototype morphing fan nozzle shown in the photograph. This prototype exploits the potential of smart materials to significantly improve the performance of existing aircraft engines by introducing new inherent capabilities for shape control, vibration damping, noise reduction, health monitoring, and flow manipulation. The novel design employs two different smart materials, a shape-memory alloy and magnetorheological fluids, to reduce the nozzle area by up to 30 percent. The prototype of the variable-area fan nozzle implements an overlapping spring leaf assembly to simplify the initial design and to provide ease of structural control. A single bundle of shape memory alloy wire actuators is used to reduce the nozzle geometry. The nozzle is subsequently held in the reduced-area configuration by using magnetorheological fluid brakes. This prototype uses the inherent advantages of shape memory alloys in providing large induced strains and of magnetorheological fluids in generating large resistive forces. In addition, the spring leaf design also functions as a return spring, once the magnetorheological fluid brakes are released, to help force the shape memory alloy wires to return to their original position. A computerized real-time control system uses the derivative-gain and proportional-gain algorithms to operate the system. This design represents a novel approach to the active control of high-bypass-ratio turbofan engines. Researchers have estimated that such engines will reduce thrust specific fuel consumption by 9 percent over that of fixed-geometry fan nozzles. This research was conducted under a cooperative agreement (NCC3-839) at the University of Akron.

  14. Silver clusters from nozzle expansions

    International Nuclear Information System (INIS)

    Hagena, O.F.

    1990-01-01

    This note reports on the first successful experiments to generate silver clusters (N≤100) in supersonic nozzle flows. A mixture of argon/silver-vapor was used expanding from a conical nozzle (0.35 mm, 10deg full cone angle, 17 mm long conical section). Source temperature and total pressure ranged up to 2200 K/300 kPa, and silver partial pressure up to 25 kPa. The data confirm the scaling laws developed to compare clustering of metals with that of rare gases. (orig.)

  15. Drift-reducing nozzles and their biological efficacy.

    Science.gov (United States)

    Nuyttens, D; Dhoop, M; De Blauwer, V; Hermann, O; Hubrechts, W; Mestdagh, I; Dekeyser, D

    2009-01-01

    In 2007 and 2008, field trials were carried out with different standard and drift-reducing nozzles in sugar beet, maize, chicory, Belgian endive (all herbicide applications), wheat (fungicide application) and potatoes (Haulm killing herbicide application). The effect of nozzle type (standard flat fan, low-drift flat fan, air injection), nozzle size (ISO 02, 03 and 04) and application volume on the biological efficacy was investigated. All applications were done using a plot sprayer with volume rates ranging from 160 to 320 l.ha(-1) at recommended dose rates with commonly used (mix of) plant protection products. For each crop, the experiments included four replicates in a randomized block design. Depending on the type of application, the efficacy was measured in terms of weed control, disease and yield level, percentage dead leaf and stem, etc. In a previous research, drift and droplet characteristics of the different techniques were measured. In general no important effect of application technique on biological efficacy was observed for the tested herbicide and fungicide applications within the interval of volume rates and droplet size tested. Drift-reducing nozzles performed similar as conventional nozzles under good spraying conditions and using a correct spray application technique.

  16. Shelf life extension for the lot AAE nozzle severance LSCs

    Science.gov (United States)

    Cook, M.

    1990-01-01

    Shelf life extension tests for the remaining lot AAE linear shaped charges for redesigned solid rocket motor nozzle aft exit cone severance were completed in the small motor conditioning and firing bay, T-11. Five linear shaped charge test articles were thermally conditioned and detonated, demonstrating proper end-to-end charge propagation. Penetration depth requirements were exceeded. Results indicate that there was no degradation in performance due to aging or the linear shaped charge curving process. It is recommended that the shelf life of the lot AAE nozzle severance linear shaped charges be extended through January 1992.

  17. Turbomachine combustor nozzle including a monolithic nozzle component and method of forming the same

    Science.gov (United States)

    Stoia, Lucas John; Melton, Patrick Benedict; Johnson, Thomas Edward; Stevenson, Christian Xavier; Vanselow, John Drake; Westmoreland, James Harold

    2016-02-23

    A turbomachine combustor nozzle includes a monolithic nozzle component having a plate element and a plurality of nozzle elements. Each of the plurality of nozzle elements includes a first end extending from the plate element to a second end. The plate element and plurality of nozzle elements are formed as a unitary component. A plate member is joined with the nozzle component. The plate member includes an outer edge that defines first and second surfaces and a plurality of openings extending between the first and second surfaces. The plurality of openings are configured and disposed to register with and receive the second end of corresponding ones of the plurality of nozzle elements.

  18. Reactor pressure vessel with forged nozzles

    Science.gov (United States)

    Desai, Dilip R.

    1993-01-01

    Inlet nozzles for a gravity-driven cooling system (GDCS) are forged with a cylindrical reactor pressure vessel (RPV) section to which a support skirt for the RPV is attached. The forging provides enhanced RPV integrity around the nozzle and substantial reduction of in-service inspection costs by eliminating GDCS nozzle-to-RPV welds.

  19. Analysis and Results from a Flush Airdata Sensing (FADS) System in Close Proximity to Firing Rocket Nozzles

    Science.gov (United States)

    Ali, Aliyah N.; Borrer, Jerry L.

    2013-01-01

    This presentation presents information regarding the nose-cap flush airdata sensing (FADS) system on Orion's Pad Abort 1 (PA-1) vehicle. The purpose of the nose-cap FADS system was to test whether or not useful data could be obtained from a FADS system if it was placed in close proximity to firing rockets nozzles like the attitude control motor (ACM) nozzles on the PA-1 launch abort system (LAS). The nose-cap FADS systems use pressure measurements from a series of pressure ports which are arranged in a cruciform pattern and flush with the surface of the vehicle to estimate values of angle of attack, angle of side-slip, Mach number, impact pressure and free-stream static pressure.

  20. Simulation of a Downsized FDM Nozzle

    DEFF Research Database (Denmark)

    Hofstätter, Thomas; Pimentel, Rodrigo; Pedersen, David B.

    2015-01-01

    This document discusses the simulat-ion of a downsized nozzle for fused deposition modelling (FDM), namely the E3D HotEnd Extruder with manufactured diameters of 200-400 μm in the nozzle tip. The nozzle has been simulated in terms of heat transfer and fluid flow giving an insight into the physical...... behavior of the polymer inside the nozzle. The extruder contains a nozzle, a heater block, a heatbreak and a heatsink additionally cooled by a fan. The diameter is located in the sub-mm re-gion allowing to reduce the size and surface roughness of the product. The simulation results were experimentally...

  1. Airflow Patterns In Nuclear Workplace - Computer Simulation And Qualitative Tests

    International Nuclear Information System (INIS)

    Haim, M.; Szanto, M.; Weiss, Y.; Kravchick, T.; Levinson, S.; German, U.

    1999-01-01

    Concentration of airborne radioactive materials inside a room can vary widely from one location to another, sometimes by orders of magnitude even for locations that are relatively close. Inappropriately placed samplers can give misleading results and. therefore, the location of air samplers is important. Proper placement of samplers cannot be determined simply by observing the position of room air supply and exhaust vents. Airflow studies, such as the release of smoke aerosols, should be used. The significance of airflow pattern studies depends on the purpose of sampling - for estimating worker intakes, warning of high concentrations. defacing airborne radioactive areas, testing for confinement of sealed radioactive materials. etc. When sampling air in rooms with complex airflow patterns, it may be useful to use qualitative airflow studies with smoke tubes, smoke candles or isostatic bubbles. The U.S. Nuclear Regulatory Commission - Regulatory Guide 8.25 [1]. suggests that an airflow study should be conducted after any changes at work area including changes in the setup of work areas, ventilation system changes, etc. The present work presents an airflow patterns study conducted in a typical room using two methods: a computer simulation and a qualitative test using a smoke tube

  2. Nozzle geometry variations on the discharge coefficient

    Directory of Open Access Journals (Sweden)

    M.M.A. Alam

    2016-03-01

    Full Text Available Numerical works have been conducted to investigate the effect of nozzle geometries on the discharge coefficient. Several contoured converging nozzles with finite radius of curvatures, conically converging nozzles and conical divergent orifices have been employed in this investigation. Each nozzle and orifice has a nominal exit diameter of 12.7×10−3 m. A 3rd order MUSCL finite volume method of ANSYS Fluent 13.0 was used to solve the Reynolds-averaged Navier–Stokes equations in simulating turbulent flows through various nozzle inlet geometries. The numerical model was validated through comparison between the numerical results and experimental data. The results obtained show that the nozzle geometry has pronounced effect on the sonic lines and discharge coefficients. The coefficient of discharge was found differ from unity due to the non-uniformity of flow parameters at the nozzle exit and the presence of boundary layer as well.

  3. Numerical study on drop formation through a micro nozzle

    International Nuclear Information System (INIS)

    Kim, Sung Il; Son, Gi Hun

    2005-01-01

    The drop ejection process from a micro nozzle is investigated by numerically solving the conservation equations for mass and momentum. The liquid-gas interface is tracked by a level set method which is extended for two-fluid flows with irregular solid boundaries. Based on the numerical results, the liquid jet breaking and droplet formation behavior is found to depend strongly on the pulse type of forcing pressure and the contact angle at the gas-liquid-solid interline. The negative pressure forcing can be used to control the formation of satelite droplets. Also, various nozzle shapes are tested to investigate their effect on droplet formation

  4. Control of Surge in Centrifugal Compressor by Using a Nozzle Injection System: Universality in Optimal Position of Injection Nozzle

    Directory of Open Access Journals (Sweden)

    Toshiyuki Hirano

    2012-01-01

    Full Text Available The passive control method for surge and rotating stall in centrifugal compressors by using a nozzle injection system was proposed to extend the stable operating range to the low flow rate. A part of the flow at the scroll outlet of a compressor was recirculated to an injection nozzle installed on the inner wall of the suction pipe of the compressor through the bypass pipe and injected to the impeller inlet. Two types of compressors were tested at the rotational speeds of 50,000 rpm and 60,000 rpm with the parameter of the circumferential position of the injection nozzle. The present experimental results revealed that the optimum circumferential position, which most effectively reduced the flow rate for the surge inception, existed at the opposite side of the tongue of the scroll against the rotational axis and did not depend on the compressor system and the rotational speeds.

  5. Transient Side Load Analysis of Out-of-Round Film-Cooled Nozzle Extensions

    Science.gov (United States)

    Wang, Ten-See; Lin, Jeff; Ruf, Joe; Guidos, Mike

    2012-01-01

    There was interest in understanding the impact of out-of-round nozzle extension on the nozzle side load during transient startup operations. The out-of-round nozzle extension could be the result of asymmetric internal stresses, deformation induced by previous tests, and asymmetric loads induced by hardware attached to the nozzle. The objective of this study was therefore to computationally investigate the effect of out-of-round nozzle extension on the nozzle side loads during an engine startup transient. The rocket engine studied encompasses a regeneratively cooled chamber and nozzle, along with a film cooled nozzle extension. The computational methodology is based on an unstructured-grid, pressure-based computational fluid dynamics formulation, and transient inlet boundary flow properties derived from an engine system simulation. Six three-dimensional cases were performed with the out-of-roundness achieved by three different degrees of ovalization, elongated on lateral y and z axes: one slightly out-of-round, one more out-of-round, and one significantly out-of-round. The results show that the separation line jump was the primary source of the peak side loads. Comparing to the peak side load of the perfectly round nozzle, the peak side loads increased for the slightly and more ovalized nozzle extensions, and either increased or decreased for the two significantly ovalized nozzle extensions. A theory based on the counteraction of the flow destabilizing effect of an exacerbated asymmetrical flow caused by a lower degree of ovalization, and the flow stabilizing effect of a more symmetrical flow, created also by ovalization, is presented to explain the observations obtained in this effort.

  6. Feedback mechanism for smart nozzles and nebulizers

    Science.gov (United States)

    Montaser, Akbar [Potomac, MD; Jorabchi, Kaveh [Arlington, VA; Kahen, Kaveh [Kleinburg, CA

    2009-01-27

    Nozzles and nebulizers able to produce aerosol with optimum and reproducible quality based on feedback information obtained using laser imaging techniques. Two laser-based imaging techniques based on particle image velocimetry (PTV) and optical patternation map and contrast size and velocity distributions for indirect and direct pneumatic nebulizations in plasma spectrometry. Two pulses from thin laser sheet with known time difference illuminate droplets flow field. Charge coupled device (CCL)) captures scattering of laser light from droplets, providing two instantaneous particle images. Pointwise cross-correlation of corresponding images yields two-dimensional velocity map of aerosol velocity field. For droplet size distribution studies, solution is doped with fluorescent dye and both laser induced florescence (LIF) and Mie scattering images are captured simultaneously by two CCDs with the same field of view. Ratio of LIF/Mie images provides relative droplet size information, then scaled by point calibration method via phase Doppler particle analyzer.

  7. Investigation of nozzle contours in the CSIR supersonic wind tunnel

    CSIR Research Space (South Africa)

    Vallabh, Bhavya

    2017-09-01

    Full Text Available technique to design the nozzle profiles for the full supersonic Mach number range 1=M=4.5 of the facility. Automatic computation was used for the profile design and a computational method analysed the test section flow characteristics. A boundary layer...

  8. Fluid Flow Nozzle Energy Harvesters

    Science.gov (United States)

    Sherrit, Stewart; Lee, Hyeong Jae; Walkenmeyer, Phillip; Winn, Tyler; Tosi, Luis Phillipe; Colonius, Tim

    2015-01-01

    Power generation schemes that could be used downhole in an oil well to produce about 1 Watt average power with long-life (decades) are actively being developed. A variety of proposed energy harvesting schemes could be used to extract energy from this environment but each of these has their own limitations that limit their practical use. Since vibrating piezoelectric structures are solid state and can be driven below their fatigue limit, harvesters based on these structures are capable of operating for very long lifetimes (decades); thereby, possibly overcoming a principle limitation of existing technology based on rotating turbo-machinery. An initial survey identified that spline nozzle configurations can be used to excite a vibrating piezoelectric structure in such a way as to convert the abundant flow energy into useful amounts of electrical power. This paper presents current flow energy harvesting designs and experimental results of specific spline nozzle/ bimorph design configurations which have generated suitable power per nozzle at or above well production analogous flow rates. Theoretical models for non-dimensional analysis and constitutive electromechanical model are also presented in this paper to optimize the flow harvesting system.

  9. RSRM Nozzle-to-Case Joint J-leg Development

    Science.gov (United States)

    Albrechtsen, Kevin U.; Eddy, Norman F.; Ewing, Mark E.; McGuire, John R.

    2003-01-01

    Since the beginning of the Space Shuttle Reusable Solid Rocket Motor (RSRM) program, nozzle-to-case joint polysulfide adhesive gas paths have occurred on several flight motors. These gas paths have allowed hot motor gases to reach the wiper O-ring. Even though these motors continue to fly safely with this condition, a desire was to reduce such occurrences. The RSRM currently uses a J-leg joint configuration on case field joints and igniter inner and outer joints. The J-leg joint configuration has been successfully demonstrated on numerous RSRM flight and static test motors, eliminating hot gas intrusion to the critical O-ring seals on these joints. Using the proven technology demonstrated on the case field joints and igniter joints, a nozzle-to-case joint J-leg design was developed for implementation on RSRM flight motors. This configuration provides an interference fit with nozzle fixed housing phenolics at assembly, with a series of pressurization gaps incorporated outboard of the joint mating surface to aid in joint pressurization and to eliminate any circumferential flow in this region. The joint insulation is bonded to the nozzle phenolics using the same pressure sensitive adhesive used in the case field joints and igniter joints. An enhancement to the nozzle-to-case joint J-leg configuration is the implementation of a carbon rope thermal barrier. The thermal barrier is located downstream of the joint bondline and is positioned within the joint in a manner where any hot gas intrusion into the joint passes through the thermal barrier, reducing gas temperatures to a level that would not affect O-rings downstream of the thermal barrier. This paper discusses the processes used in reaching a final nozzle-to-case joint J-leg design, provides structural and thermal results in support of the design, and identifies fabrication techniques and demonstrations used in arriving at the final configuration.

  10. On computational fluid dynamics models for sinonasal drug transport: Relevance of nozzle subtraction and nasal vestibular dilation.

    Science.gov (United States)

    Basu, Saikat; Frank-Ito, Dennis O; Kimbell, Julia S

    2018-04-01

    Generating anatomically realistic 3-dimensional (3D) models of the human sinonasal cavity for numerical investigations of sprayed drug transport presents a host of methodological ambiguities. For example, subject-specific radiographic images used for 3D reconstructions typically exclude spray bottles. Subtracting a bottle contour from the 3D airspace and dilating the anterior nasal vestibule for nozzle placement augment the complexity of model building. So we explored the question: how essential are these steps to adequately simulate nasal airflow and identify the optimal delivery conditions for intranasal sprays? In particular, we focused on particle deposition patterns in the maxillary sinus, a critical target site for chronic rhinosinusitis. The models were reconstructed from postsurgery computed tomography scans for a 39-year-old Caucasian male, with chronic rhinosinusitis history. Inspiratory airflow patterns during resting breathing are reliably tracked through computational fluid dynamics-based steady-state laminar-viscous modeling, and such regimes portray relative lack of sensitivity to inlet perturbations. Consequently, we hypothesized that the posterior airflow transport and the particle deposition trends should not be radically affected by the nozzle subtraction and vestibular dilation. The study involved 1 base model and 2 derived models; the latter 2 with nozzle contours (2 different orientations) subtracted from the dilated anterior segment of the left vestibule. We analyzed spray transport in the left maxillary sinus for multiple release conditions. Similar release points, localized on an approximately 2 mm × 4.5 mm contour, facilitated improved maxillary deposition in all 3 test cases. This suggests functional redundancy of nozzle insertion in a 3D numerical model for identifying the optimal spray release locations. Copyright © 2017 John Wiley & Sons, Ltd.

  11. Inviscid Design of Hypersonic Wind Tunnel Nozzles for a Real Gas

    Science.gov (United States)

    Korte, J. J.

    2000-01-01

    A straightforward procedure has been developed to quickly determine an inviscid design of a hypersonic wind tunnel nozzle when the test crash is both calorically and thermally imperfect. This real gas procedure divides the nozzle into four distinct parts: subsonic, throat to conical, conical, and turning flow regions. The design process is greatly simplified by treating the imperfect gas effects only in the source flow region. This simplification can be justified for a large class of hypersonic wind tunnel nozzle design problems. The final nozzle design is obtained either by doing a classical boundary layer correction or by using this inviscid design as the starting point for a viscous design optimization based on computational fluid dynamics. An example of a real gas nozzle design is used to illustrate the method. The accuracy of the real gas design procedure is shown to compare favorably with an ideal gas design based on computed flow field solutions.

  12. Design and Fabrication Development of J-2X Engine Metallic Nozzle Extension

    Science.gov (United States)

    Kopicz, C.; Gradl, P.

    2015-01-01

    Maximized rocket engine performance is in part derived from expanding combustion gasses through the rocket nozzle. For upper stage engines the nozzles can be quite large. On the J-2X engine, an uncooled extension of a regeneratively cooled nozzle is used to expand the combustion gasses to a targeted exit pressure which is defined by an altitude for the desired maximum performance. Creating a J-2X nozzle extension capable of surviving the loads of test and flight environments while meeting engine system performance requirements required development of new processes and facilities. Meeting the challenges of the development resulted in concurrent J-2X nozzle extension design and fabrication. This paper describes how some of the design and fabrication challenges were resolved.

  13. Design and preliminary test results at Mach 5 of an axisymmetric slotted sound shield. [for supersonic wind tunnels (noise reduction in wind tunnel nozzles)

    Science.gov (United States)

    Beckwith, I. E.; Spokowski, A. J.; Harvey, W. D.; Stainback, P. C.

    1975-01-01

    The basic theory and sound attenuation mechanisms, the design procedures, and preliminary experimental results are presented for a small axisymmetric sound shield for supersonic wind tunnels. The shield consists of an array of small diameter rods aligned nearly parallel to the entrance flow with small gaps between the rods for boundary layer suction. Results show that at the lowest test Reynolds number (based on rod diameter) of 52,000 the noise shield reduced the test section noise by about 60 percent ( or 8 db attenuation) but no attenuation was measured for the higher range of test reynolds numbers from 73,000 to 190,000. These results are below expectations based on data reported elsewhere on a flat sound shield model. The smaller attenuation from the present tests is attributed to insufficient suction at the gaps to prevent feedback of vacuum manifold noise into the shielded test flow and to insufficient suction to prevent transition of the rod boundary layers to turbulent flow at the higher Reynolds numbers. Schlieren photographs of the flow are shown.

  14. Modified computation of the nozzle damping coefficient in solid rocket motors

    Science.gov (United States)

    Liu, Peijin; Wang, Muxin; Yang, Wenjing; Gupta, Vikrant; Guan, Yu; Li, Larry K. B.

    2018-02-01

    In solid rocket motors, the bulk advection of acoustic energy out of the nozzle constitutes a significant source of damping and can thus influence the thermoacoustic stability of the system. In this paper, we propose and test a modified version of a historically accepted method of calculating the nozzle damping coefficient. Building on previous work, we separate the nozzle from the combustor, but compute the acoustic admittance at the nozzle entry using the linearized Euler equations (LEEs) rather than with short nozzle theory. We compute the combustor's acoustic modes also with the LEEs, taking the nozzle admittance as the boundary condition at the combustor exit while accounting for the mean flow field in the combustor using an analytical solution to Taylor-Culick flow. We then compute the nozzle damping coefficient via a balance of the unsteady energy flux through the nozzle. Compared with established methods, the proposed method offers competitive accuracy at reduced computational costs, helping to improve predictions of thermoacoustic instability in solid rocket motors.

  15. Wear surface studies on coal water slurry nozzles in industrial boilers

    Energy Technology Data Exchange (ETDEWEB)

    Ding Zeliang [Hunan Engineering Technology Key Laboratory of Inorganic and Nonmetal Materials, Hunan University of Technology, Zhuzhou 412008, Hunan Province (China)]. E-mail: dingzl@263.net; Deng Jianxin [Department of Mechanical Engineering, Shandong University, Jinan 250061, Shandong Province (China)]. E-mail: jxdeng@sdu.edu.cn; Li Jianfeng [Department of Mechanical Engineering, Shandong University, Jinan 250061, Shandong Province (China)]. E-mail: ljf@sdu.edu.cn

    2007-07-01

    In this study, Al{sub 2}O{sub 3}/(W,Ti)C ceramic, WC/Co cemented carbide, and 1Cr18Ni9Ti stainless steel were produced to be used as nozzle materials in coal water slurry (CWS) industry boilers. Coal water slurry burning tests with these nozzles were carried out. The wear surface features of the nozzles made from these materials were examined. The results showed that the wear mechanisms of nozzles varied from entry to exit. The material removal of Al{sub 2}O{sub 3}/(W,Ti)C ceramic nozzle in CWS atomizing and burning is attributed to a mixed mode damage by brittle fracture, polishing, thermal cracking and chipping. The nozzle entry section appears to be entirely brittle in nature with evidence of large scale-chipping. The centre bore area showed a polishing effect with a very smooth surface. While the exit section exhibits cracking owing to the large thermal shock. Examination of the eroded bore surface of the WC/Co cemented carbide nozzles demonstrated that the wear occurred through preferential removal of the metal binder (Co) followed by pluck-out of the exposed WC grains at the entry zone, while the center and the exit zone showed polishing action. The primary wear mechanisms of 1Cr18Ni9Ti stainless steel nozzle exhibited plastic deformation at the entry zone, and plowing and micro-cutting at the other zones by the eroded particles.

  16. Pacing pattern in a 30-minute maximal cycling test.

    Science.gov (United States)

    Chaffin, Morgan E; Berg, Kris; Zuniga, Jorge; Hanumanthu, Vidya Sagar

    2008-11-01

    The purpose of this study was to investigate the pacing pattern and associated physiological effects in competitive cyclists who performed a 30-minute maximal cycling test. Measurements included oxygen uptake (V O2), heart rate (HR), blood lactate concentration (BLC), rating of perceived exertion (RPE), and work rate in watts. Twelve well-trained amateur cyclists (seven men and five women) whose mean age was 32.4 +/- 8.6 years participated in this study. They performed a 30-minute self-paced maximal cycling test using their own performance road bike attached to a CompuTrainer Pro, which allowed the assessment of work rate (W). During the test, work rate, V O2, and HR were measured every 30 seconds. Subjects' BLC and RPE were obtained every 5 minutes. Results indicate that no significant differences existed across three 10-minute periods for work rate, HR, or V O2. However, RPE at 30 minutes was significantly greater than RPE at 10 and 20 minutes (both p minutes was also greater than the RPE at 10 minutes (p 30 seconds of the test. The associated V O2 was fairly constant over time, whereas HR rose linearly and gradually. It was concluded that pacing in a 30-minute maximal exercise bout performed in the laboratory in experienced cyclists varies minimally until the last 30 seconds. Knowledge of pacing strategy and the linked physiological responses may be helpful to exercise scientists in optimizing performance in the endurance athlete.

  17. BRCA testing of breast cancer patients: medical specialists' referral patterns, knowledge and attitudes to genetic testing

    NARCIS (Netherlands)

    van Riel, E.; Wárlám-Rodenhuis, C. C.; Verhoef, S.; Rutgers, E. J. T. H.; Ausems, M. G. E. M.

    2010-01-01

    This study explores knowledge about hereditary breast cancer, attitudes about BRCA testing and referral pattern to a family cancer clinic among medical specialists. A total of 92 questionnaires were completed by surgeons (38), medical oncologists (29), radiation oncologists (13) and radiologists

  18. Crack of reactor vessel upper head penetration nozzles in Korean nuclear plants

    International Nuclear Information System (INIS)

    Doh, E.; Lee, T-S.; Kim, J-Y.; Lee, C-H.

    2014-01-01

    Since the first CRDM nozzles of reactor vessel head at Kori unit 1 in Korea were inspected in 2003, no CRDM nozzle cracks had been revealed prior to the inspection at Hanbit unit 3 in October 2012, even though many foreign plants had been reporting PWSCC cracks. In October 2012, seven axial cracks from 6 CRDM nozzles at Hanbit unit 3, and in November 2013, six axial cracks from 6 CRDM nozzles at Hanbit unit 4 were detected by TOFD Ultrasonic testing from ID of nozzles. There were confirmed to be PWSCC by Dye penetrant testing and Replica on the surface of J-groove weld of CRDM nozzles. Both plants are OPR-1000 types. All flaws started from the surface of J-groove weld at interface with OD of nozzle, but did not grow up to the top of J-groove weld, and did not make any Leak path up to head outside. The Performance Demonstration Initiative (PDI) system of CRDM nozzle inspection for Westinghouse type plants has been applied in Korea since July 2011. However, its application for OPR-1000 is still under development in Korea. The experience of PDI inspection for Westinghouse type plant contributed greatly to the detection and evaluation of PWSCC of CRDM nozzles at OPR- 1000 of Hanbit unit 3 & 4. The experimentally based procedure of flaw detection and the enhanced detection technique of examiners made it possible to detect and to determine the PWSCC indications. Embedded Flaw Repair process was approved by government authority, and the repair of the 6 CRDM nozzles in each plant was conducted by a consortium of Westinghouse and KPS. (author)

  19. Variable volume combustor with pre-nozzle fuel injection system

    Science.gov (United States)

    Keener, Christopher Paul; Johnson, Thomas Edward; McConnaughhay, Johnie Franklin; Ostebee, Heath Michael

    2016-09-06

    The present application provides a combustor for use with a gas turbine engine. The combustor may include a number of fuel nozzles, a pre-nozzle fuel injection system supporting the fuel nozzles, and a linear actuator to maneuver the fuel nozzles and the pre-nozzle fuel injection system.

  20. Turbojet-exhaust-nozzle secondary-airflow pumping as an exit control of an inlet-stability bypass system for a Mach 2.5 axisymmetric mixed-compression inlet. [Lewis 10- by 10-ft. supersonic wind tunnel test

    Science.gov (United States)

    Sanders, B. W.

    1980-01-01

    The throat of a Mach 2.5 inlet that was attached to a turbojet engine was fitted with large, porous bleed areas to provide a stability bypass system that would allow a large, stable airflow range. Exhaust-nozzle, secondary-airflow pumping was used as the exit control for the stability bypass airflow. Propulsion system response and stability bypass performance were obtained for several transient airflow disturbances, both internal and external. Internal airflow disturbances included reductions in overboard bypass airflow, power lever angle, and primary-nozzle area, as well as compressor stall. Nozzle secondary pumping as a stability bypass exit control can provide the inlet with a large stability margin with no adverse effects on propulsion system performance.

  1. Fractal analysis of agricultural nozzles spray

    Directory of Open Access Journals (Sweden)

    Francisco Agüera

    2012-02-01

    Full Text Available Fractal scaling of the exponential type is used to establish the cumulative volume (V distribution applied through agricultural spray nozzles in size x droplets, smaller than the characteristic size X. From exponent d, we deduced the fractal dimension (Df which measures the degree of irregularity of the medium. This property is known as 'self-similarity'. Assuming that the droplet set from a spray nozzle is self-similar, the objectives of this study were to develop a methodology for calculating a Df factor associated with a given nozzle and to determine regression coefficients in order to predict droplet spectra factors from a nozzle, taking into account its own Df and pressure operating. Based on the iterated function system, we developed an algorithm to relate nozzle types to a particular value of Df. Four nozzles and five operating pressure droplet size characteristics were measured using a Phase Doppler Particle Analyser (PDPA. The data input consisted of droplet size spectra factors derived from these measurements. Estimated Df values showed dependence on nozzle type and independence of operating pressure. We developed an exponential model based on the Df to enable us to predict droplet size spectra factors. Significant coefficients of determination were found for the fitted model. This model could prove useful as a means of comparing the behavior of nozzles which only differ in not measurable geometric parameters and it can predict droplet spectra factors of a nozzle operating under different pressures from data measured only in extreme work pressures.

  2. Remotely replaceable fuel and feed nozzles for the NWCF calciner vessel

    International Nuclear Information System (INIS)

    Fletcher, R.D.; Carter, J.A.; May, K.W.

    1978-01-01

    The development and testing of remotely replaceable fuel and feed nozzles for calcination of liquid radioactive wastes in the calciner vessel of the New Waste Calcining Facility (NWCF) being built at the Idaho National Engineering Laboratory are described. A complete fuel nozzle assembly was fabricated and tested at the Remote Maintenance Development Facility to evolve design refinements, identify required support equipment, and develop handling techniques. The design also provided for remote replacement of the nozzle support carriage and adjacent feed and fuel pipe loops using two pairs of master-slave manipulators

  3. Remotely replaceable fuel and feed nozzles for the new waste calcining facility calciner vessel

    International Nuclear Information System (INIS)

    Fletcher, R.D.; Carter, J.A.; May, K.W.

    1978-01-01

    The development and testing of remotely replaceable fuel and feed nozzles for calcination of liquid radioactive wastes in the calciner vessel of the New Waste Calcining Facility being built at the Idaho National Engineering Laboratory is described. A complete fuel nozzle assembly was fabricated and tested at the Remote Maintenance Development Facility to evolve design refinements, identify required support equipment, and develop handling techniques. The design also provided for remote replacement of the nozzle support carriage and adjacent feed and fuel pipe loops using two pairs of master-slave manipulators

  4. High Pressure Water Stripping Using Multi-Orifice Nozzles

    Science.gov (United States)

    Hoppe, David

    1999-01-01

    The use of multi-orifice rotary nozzles greatly increases the speed and stripping effectiveness of high pressure water blasting systems, but also greatly increases the complexity of selecting and optimizing the operating parameters. The rotational speed of the nozzle must be coupled with its transverse velocity as it passes across the surface of the substrate being stripped. The radial and angular positions of each orifice must be included in the analysis of the nozzle configuration. Orifices at the outer edge of the nozzle head move at a faster rate than the orifices located near the center. The energy transmitted to the surface from the impact force of the water stream from an outer orifice is therefore spread over a larger area than energy from an inner orifice. Utilizing a larger diameter orifice in the outer radial positions increases the total energy transmitted from the outer orifice to compensate for the wider distribution of energy. The total flow rate from the combination of all orifices must be monitored and should be kept below the pump capacity while choosing orifice to insert in each position. The energy distribution from the orifice pattern is further complicated since the rotary path of all the orifices in the nozzle head pass through the center section. All orifices contribute to the stripping in the center of the path while only the outer most orifice contributes to the stripping at the edge of the nozzle. Additional orifices contribute to the stripping from the outer edge toward the center section. With all these parameters to configure and each parameter change affecting the others, a computer model was developed to track and coordinate these parameters. The computer simulation graphically indicates the cumulative affect from each parameter selected. The result from the proper choices in parameters is a well designed, highly efficient stripping system. A poorly chosen set of parameters will cause the nozzle to strip aggressively in some areas

  5. Axisymmetric nozzles with chamfered contraction

    Czech Academy of Sciences Publication Activity Database

    Tesař, Václav

    2017-01-01

    Roč. 263, August (2017), s. 147-158 ISSN 0924-4247 Institutional support: RVO:61388998 Keywords : nozzles * chamfering * invariant Subject RIV: BK - Fluid Dynamics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 2.499, year: 2016 http://ac.els-cdn.com/S0924424716310329/1-s2.0-S0924424716310329-main.pdf?_tid=f953dc4c-873c-11e7-b8d0-00000aacb35d&acdnat=1503408341_51527a384c272a3c4e8f43e6046d789d

  6. PIV Measurements of Chevrons on F400-Series Tactical Aircraft Nozzle Model

    Science.gov (United States)

    Bridges, James; Wernet, Mark P.; Frate, Franco C.

    2011-01-01

    Reducing noise of tactical jet aircraft has taken on fresh urgency as core engine technologies allow higher specific-thrust engines and as society become more concerned for the health of its military workforce. Noise reduction on this application has lagged the commercial field as incentives for quieting military aircraft have not been as strong as in their civilian counterparts. And noise reduction strategies employed on civilian engines may not be directly applicable due to the differences in exhaust system architecture and mission. For instance, the noise reduction technology of chevrons, examined in this study, will need to be modified to take into account the special features of tactical aircraft nozzles. In practice, these nozzles have divergent slats that are tied to throttle position, and at take off the jet flow is highly overexpanded as the nozzle is optimized for cruise altitude rather than sea level. In simple oil flow visualization experiments conducted at the onset of the current test program flow barely stays attached at end of nozzle at takeoff conditions. This adds a new twist to the design of chevrons. Upon reaching the nozzle exit the flow shrinks inward radially, meaning that for a chevron to penetrate the flow it must extend much farther away from the baseline nozzle streamline. Another wrinkle is that with a variable divergence angle on the nozzle, the effective penetration will differ with throttle position and altitude. The final note of realism introduced in these experiments was to simulate the manner in which bypass flow is bled into the nozzle wall in real engines to cool the nozzle, which might cause very fat boundary layer at exit. These factors, along with several other issues specific to the application of chevrons to convergent-divergent nozzles have been explored with particle image velocimetry measurements and are presented in this paper.

  7. The separation nozzle process for uranium isotope enrichment

    International Nuclear Information System (INIS)

    Becker, E.W.

    1977-01-01

    The paper covers the most important steps in the technological development and the future prospects of the separation nozzle process. In this process uranium isotope separation is brought about by the mass dependence of the centrifugal forces in a curved flow of a UF 6 /H 2 mixture. Due to the large excess in hydrogen, the high ratio of UF 6 flow velocity to thermal velocity required for an effective isotope separation is obtained at relatively low expansion ratios and, accordingly, with relatively low gas-dynamic losses. As the optimum Reynolds number of the curved jet is comparatively low, and as a high absolute pressure is essential for economic reasons, the characteristic dimensions of the nozzle systems are made as small as possible. For commercial application in the near future, systems involving mechanical jet deflection have been developed. Promising results were, however, also obtained with separation nozzle systems generating a streamline curvature by the interaction of opposed jets. Most of the development work has been done at the Nuclear Research Centre, Karlsruhe. Since 1970 the STEAG company (FRG) has been involved in the commercial implementation of the process. Two industrial-scale separative stages were tested successfully. This work constitutes the basis of planning of a separation nozzle demonstration plant to be built in Brazil. (author)

  8. Method and apparatus for setting precise nozzle/belt and nozzle/edge dam block gaps

    Science.gov (United States)

    Carmichael, Robert J.; Dykes, Charles D.; Woodrow, Ronald

    1989-05-16

    A pair of guide pins are mounted on sideplate extensions of the caster and mating roller pairs are mounted on the nozzle assembly. The nozzle is advanced toward the caster so that the roller pairs engage the guide pins. Both guide pins are remotely adjustable in the vertical direction by hydraulic cylinders acting through eccentrics. This moves the nozzle vertically. The guide pin on the inboard side of the caster is similarly horizontally adjustable. The nozzle roller pair which engage the inboard guide pin are flanged so that the nozzle moves horizontally with the inboard guide pin.

  9. High mass throughput particle generation using multiple nozzle spraying

    Science.gov (United States)

    Pui, David Y.H.; Chen, Da-Ren

    2004-07-20

    Spraying apparatus and methods that employ multiple nozzle structures for producing multiple sprays of particles, e.g., nanoparticles, for various applications, e.g., pharmaceuticals, are provided. For example, an electrospray dispensing device may include a plurality of nozzle structures, wherein each nozzle structure is separated from adjacent nozzle structures by an internozzle distance. Sprays of particles are established from the nozzle structures by creating a nonuniform electrical field between the nozzle structures and an electrode electrically isolated therefrom.

  10. Erosion-Resistant Water-Blast Nozzle

    Science.gov (United States)

    Roberts, Marion L.; Rice, R. M.; Cosby, S. A.

    1988-01-01

    Design of nozzle reduces erosion of orifice by turbulent high-pressure water flowing through it. Improved performance and resistance to erosion achieved by giving interior nozzle surface long, gradual convergence before exit orifice abrupt divergence after orifice and by machining surface to smooth finish.

  11. Black hole acoustics in the minimal geometric deformation of a de Laval nozzle

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, Roldao da [Universidade Federal do ABC-UFABC, Centro de Matematica, Computacao e Cognicao, Santo Andre (Brazil)

    2017-05-15

    The correspondence between sound waves, in a de Laval propelling nozzle, and quasinormal modes emitted by brane-world black holes deformed by a 5D bulk Weyl fluid are here explored and scrutinized. The analysis of sound waves patterns in a de Laval nozzle in the laboratory, reciprocally, is here shown to provide relevant data about the 5D bulk Weyl fluid and its on-brane projection, comprised by the minimal geometrically deformed compact stellar distribution on the brane. Acoustic perturbations of the gas fluid flow in the de Laval nozzle are proved to coincide with the quasinormal modes of black holes solutions deformed by the 5D Weyl fluid, in the geometric deformation procedure. Hence, in a phenomenological Eoetvoes-Friedmann fluid brane-world model, the realistic shape of a de Laval nozzle is derived and its consequences studied. (orig.)

  12. Repositioning through Culture: Testing Change in Connectivity Patterns

    Directory of Open Access Journals (Sweden)

    Beatriz Plaza

    2016-12-01

    Full Text Available Symbolic knowledge-driven innovations can play an important role in the economic development of cities and regions. Cultural events and infrastructures can act as powerful connectivity engines, generating new connections, rewiring links, and repositioning institutions/cities/regions on the Internet map. Within this framework, this paper aims to contribute to the analytical understanding of culture-led repositioning. For this purpose we perform regression analysis with cultural networks (observational cross-sectional network data from digital media for a specific cultural case study: the Basque Culinary Center (BCC, a higher education faculty of haute cuisine promoted by the University of Mondragon along with a group of Michelin-starred chefs. Results show that a cultural sector, such as haute cuisine, can contribute to structural changes in connectivity patterns, putting an institution/city/region on the media map. It is the connection (in the online press of the BCC to the influential Michelin-starred chefs that can fuel the accumulation of press articles (media items on the BCC; and it is precisely this accumulation of press articles that can impact BCC revenues. Put differently, the co-branding between the influential Michelin chefs and the BCC may have put the BCC on the press map, promoting new student registrations and fostering Basque haute cuisine. The main contribution of this article is a prototype of regression analysis to test repositioning with network data.

  13. Construction and evaluation of a hollow cone type nozzle with ceramic nanocomposites

    Directory of Open Access Journals (Sweden)

    F Amirshaghaghi

    2015-09-01

    Full Text Available Introduction: In order to improve the use of pesticides and pesticide consumption and prevent environmental pollution, manufactures and scientists have considered two major trends. The first major trend is improving techniques that are practical and effective use of small quantities of chemicals to reduce the negative effect of residues of pesticides. The use of new methods usually requires investment and cost. The second major trend is changing the parts that are more important to reform the sprayer components in order to reduce pollution, mainly by including engineering controls, and design and construction of appropriate nozzles. The optimization can be done with the least expensive pesticide. Nozzle is a device for spraying the solution in the form of particles with a certain pattern. Tip of a nozzle is placed in the nozzle’s body and has many different types. The main factors in choosing tips include: material, pattern of distribution, spray angle and the amount of the solution. The spray tip may be made of aluminum, brass, nylon, stainless steel, ceramic or other materials. Nanocomposites are composites that contain at least one component with dimensions in the nanometer range between 1 to 100 nm. This material is suitable as an alternative to overcome the limitations that exist with integrated microcomposites. The aim of this study was the construction and evaluation of a sprayer nozzle with ceramic nanocomposites with good shelf life and optimum performance. Materials and methods: This research was supported by the Agricultural Engineering Research Institute and Nanotechnology Committee of the Ministry of Agriculture. The operations of this study were as follows: 1- Preparing of materials, including alumina powder and stabilized zirconia powder with yttrium. 2- Design and manufacture of molds. 3- Preparation of the samples pressing operations. 4- Zintering of samples to achieve high density. 5- Tests to determine the quality of the

  14. Icing Nozzle Element Optimization Test, January 1979

    Science.gov (United States)

    1979-08-20

    444. .9 .8~. 9. flf9, . ... 90. WW0’t 4, . ww : IN. at9 I * 99 x8 ^V’ 0. Z,. .. C44A N i~~~~~ei 0 149 8 0 ’ 4 4 - a LI V * C . 4 % 4 9 . 0 . - S 004...09- h . .4 .t .. .8 . TT T at9 a) " wS- ~ .- 9e P @ - x. at ww *C PP - 9 w w - f 0 .4 4 0 0 4 0 4 .0 84447 4 0 0 . 4- 4 he~t * *0*0 *0* 000 40 4. 4.W

  15. Calculation of Propulsive Nozzle Flowfields in Multidiffusing Chemically Reacting Environments. Ph.D. Thesis - Purdue Univ.

    Science.gov (United States)

    Kacynski, Kenneth John

    1994-01-01

    An advanced engineering model has been developed to aid in the analysis and design of hydrogen/oxygen chemical rocket engines. The complete multispecies, chemically reacting and multidiffusing Navier-Stokes equations are modelled, including the Soret thermal diffusion and the Dufour energy transfer terms. In addition to the spectrum of multispecies aspects developed, the model developed in this study is also conservative in axisymmetric flow for both inviscid and viscous flow environments and the boundary conditions employ a viscous, chemically reacting, reference plane characteristics method. Demonstration cases are presented for a 1030:1 area ratio nozzle, a 25 lbf film cooled nozzle, and a transpiration cooled plug and spool rocket engine. The results indicate that the thrust coefficient predictions of the 1030:1 and the 25 lbf film cooled nozzle are within 0.2 to 0.5 percent, respectively, of experimental measurements when all of the chemical reaction and diffusion terms are considered. Further, the model's predictions agree very well with the heat transfer measurements made in all of the nozzle test cases. The Soret thermal diffusion term is demonstrated to have a significant effect on the predicted mass fraction of hydrogen along the wall of the nozzle in both the laminar flow 1030:1 nozzle and the turbulent flow plug and spool nozzle analysis cases performed. Further, the Soret term was shown to represent an important fraction of the diffusion fluxes occurring in a transpiration cooled rocket engine.

  16. Radiometric probe design for the measurement of heat flux within a solid rocket motor nozzle

    Science.gov (United States)

    Goldey, Charles L.; Laughlin, William T.; Popper, Leslie A.

    1996-11-01

    Improvements to solid rocket motor (SRM) nozzle designs and material performance is based on the ability to instrument motors during test firings to understand the internal combustion processes and the response of nozzle components to the severe heating environment. Measuring the desired parameters is very difficult because the environment inside of an SRM is extremely severe. Instrumentation can be quickly destroyed if exposed to the internal rocket motor environment. An optical method is under development to quantify the heating of the internal nozzle surface. A radiometric probe designed for measuring the thermal response and material surface recession within a nozzle while simultaneously confining the combustion products has been devised and demonstrated. As part of the probe design, optical fibers lead to calibrated detectors that measure the interior nozzle thermal response. This two color radiometric measurement can be used for a direct determination of the total heat flux impinging on interior nozzle surfaces. This measurement has been demonstrated using a high power CO2 laser to simulate SRM nozzle heating conditions on carbon phenolic and graphite phenolic materials.

  17. Nozzle dam design improvement using composite material of the steam generator in nuclear power plants

    International Nuclear Information System (INIS)

    Kim, S. H.; Jung, S. H.; Lee, S. S.; Lee, Y. S.

    2000-01-01

    The period of normal shut down and maintenance of a nuclear power plants can be remarkably shortened by doing the refueling work with inspection of a steam generator simultaneously. The nozzle dams in a steam generator are to block the back flow of coolant from the reactor cavity to the steam generator. The installation and removal of the nozzle dams have been attempted by using a robot system in stead of human workers in order to protect from the high radiation exposure and harse working environment in a steam generator. The weight of the nozzle dam must be reduced for the convenience of the robot operation. In this paper, a lighter nozzle dams were designed to keep structural integrity. The nozzle dams have been manufactured using various material such as carbon-epoxy, glass-epoxy, honey comb and aluminum plate. The variation in mechanical properties of composites with respect to radiation emission has been investigated. In order to verify the structural integrity of the nozzle dam, the stress analyses have performed using ANSYS finite element program. The hydrostatic pressure test was performed to mock-up. The maximum stress and the maximum displacement of the composite nozzle dams are measured and compared to that obtained by finite element analyses

  18. External Cylindrical Nozzle with Controlled Vacuum

    Directory of Open Access Journals (Sweden)

    V. N. Pil'gunov

    2015-01-01

    Full Text Available There is a developed design of the external cylindrical nozzle with a vacuum camera. The paper studies the nozzle controllability of flow rate via regulated connection of the evacuated chamber to the atmosphere through an air throttle. Working capacity of the nozzle with inlet round or triangular orifice are researched. The gap is provided in the nozzle design between the external wall of the inlet orifice and the end face of the straight case in the nozzle case. The presented mathematical model of the nozzle with the evacuated chamber allows us to estimate the expected vacuum amount in the compressed section of a stream and maximum permissible absolute pressure at the inlet orifice. The paper gives experimental characteristics of the fluid flow process through the nozzle for different values of internal diameter of a straight case and an extent of its end face remoteness from an external wall of the inlet orifice. It estimates how geometry of nozzle constructive elements influences on the volume flow rate. It is established that the nozzle capacity significantly depends on the shape of inlet orifice. Triangular orifice nozzles steadily work in the mode of completely filled flow area of the straight case at much more amounts of the limit pressure of the flow. Vacuum depth in the evacuated chamber also depends on the shape of inlet orifice: the greatest vacuum is reached in a nozzle with the triangular orifice which 1.5 times exceeds the greatest vacuum with the round orifice. Possibility to control nozzle capacity through the regulated connection of the evacuated chamber to the atmosphere was experimentally estimated, thus depth of flow rate regulation of the nozzle with a triangular orifice was 45% in comparison with 10% regulation depth of the nozzle with a round orifice. Depth of regulation calculated by a mathematical model appeared to be much more. The paper presents experimental dependences of the flow coefficients of nozzle input orifice

  19. Analysis and Results from a Flush Airdata Sensing System in Close Proximity to Firing Rocket Nozzles

    Science.gov (United States)

    Ali, Aliyah N.; Borrer, Jerry L.

    2013-01-01

    This paper presents information regarding the nosecap Flush Airdata Sensing (FADS) system on Orion’s Pad Abort 1 (PA-1) vehicle. The purpose of the nosecap FADS system was to test whether or not useful data could be obtained from a FADS system if it was placed in close proximity to firing rocket nozzles like the Attitude Control Motor (ACM) nozzles on the PA-1 Launch Abort System. The nosecap FADS system used pressure measurements from a series of pressure ports which were arranged in a cruciform pattern and flush with the surface of the vehicle to estimate values of angle of attack, angle of sideslip, Mach number, impact pressure, and freestream static pressure. This paper will present the algorithms employed by the FADS system along with the development of the calibration datasets and a comparison of the final results to the Best Estimated Trajectory (BET) data for PA-1. Also presented in this paper is a Computational Fluid Dynamics (CFD) study to explore the impact of the ACM on the nosecap FADS system. The comparison of the nosecap FADS system results to the BET and the CFD study showed that more investigation is needed to quantify the impact of the firing rocket motors on the FADS system.

  20. Multiple Exhaust Nozzle Effects on J-2X Gas Generator Outlet Impedance

    Science.gov (United States)

    Kenny, R. Jeremy; Muss, Jeffrey; Hulka, James R.; Casiano, Matthew

    2010-01-01

    The current test setup of the J-2X gas generator system uses a multiple nozzle configuration to exhaust hot gases to drive the propellant supply turbines. Combustion stability assessment of this gas generator design requires knowledge of the impedance effects the multiple nozzle configuration creates on the combustion chamber acoustic modes. Parallel work between NASA and Sierra Engineering is presented, showing two methods used to calculate the effective end impedance resulting from multiple nozzle configurations. The NASA method is a simple estimate of the effective impedance using the long wavelength approximation. Sierra Engineering has developed a more robust numerical integration method implemented in ROCCID to accommodate for multiple nozzles. Analysis using both methods are compared to J-2X gas generator test data collected over the past year.

  1. Content Coverage of Single-Word Tests Used to Assess Common Phonological Error Patterns

    Science.gov (United States)

    Kirk, Cecilia; Vigeland, Laura

    2015-01-01

    Purpose: This review evaluated whether 9 single-word tests of phonological error patterns provide adequate content coverage to accurately identify error patterns that are active in a child's speech. Method: Tests in the current study were considered to display sufficient opportunities to assess common phonological error patterns if they…

  2. The Investigation of the Cavitation Phenomenon in the Laval Nozzle with Full and Partial Surface Wetting

    Directory of Open Access Journals (Sweden)

    Jablonská Jana

    2017-04-01

    Full Text Available The article deals with the cavitation phenomenon affected by full and partial wetting of the wall. For the numerical computation of flow in the Laval nozzle the Schnerr-Sauer cavitation model was tested and was used for cavitation research of flow within the nozzle considering partial surface wetting. The coefficient of wetting for various materials was determined using experimental, theoretical and numerical methods of fluid flow due to partial surface wetting.

  3. Numerical hydraulic analysis of the turbulent contraction nozzle flow for IFMIF target application

    International Nuclear Information System (INIS)

    Gordeev, S.; Heinzel, V.; Stieglitz, R.

    2010-01-01

    IFMIF (International Fusion Materials Irradiation Facility) is an accelerator based deuteron-lithium (D-Li) neutron source to simulate the neutron irradiation field in a fusion reactor. The target assembly of the IFMIF consists of a nozzle, which has to form a stable lithium jet. Therefore, a flat uniform velocity distribution at the nozzle outlets cross-section with a simultaneously low turbulence intensity is required to ensure a safe operation. The general idea in the nozzle design is to produce a constant slug shaped velocity profile at the nozzles outlet cross-section with a simultaneously low homogeneously spread turbulence intensity. Additionally, the contraction length should be kept as short as possible in order to reduce the spatial and the fabrication effort. Such flow conditions are attained by using Shimas function with an axial contraction ratio of 10 as considered as a reference for IFMIF. However, a one-step contraction causes a flow separation and hence the use of Shimas method requires a two-step nozzle with first a contraction ratio of 4 followed by another with 2.5 by which the axial dimensions of the nozzle increase in size. Within this article the turbulent flow within several one and two-step nozzle types are numerically analysed by means of the V2F model, which has been validated to depict the flow most accurately in a previous work. The study exhibits that an optimized one-step nozzle is capable to generate an optimal flow pattern the IFMIF lithium target requiring a significantly shorter dimension than the reference design.

  4. Numerical hydraulic analysis of the turbulent contraction nozzle flow for IFMIF target application

    Energy Technology Data Exchange (ETDEWEB)

    Gordeev, S., E-mail: gordeev@iket.fzk.d [Research Centre of Karlsruhe, Institute for Nuclear and Energy Technologies, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Heinzel, V.; Stieglitz, R. [Research Centre of Karlsruhe, Institute for Neutronic and Reactor Technologies, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

    2010-12-15

    IFMIF (International Fusion Materials Irradiation Facility) is an accelerator based deuteron-lithium (D-Li) neutron source to simulate the neutron irradiation field in a fusion reactor. The target assembly of the IFMIF consists of a nozzle, which has to form a stable lithium jet. Therefore, a flat uniform velocity distribution at the nozzle outlets cross-section with a simultaneously low turbulence intensity is required to ensure a safe operation. The general idea in the nozzle design is to produce a constant slug shaped velocity profile at the nozzles outlet cross-section with a simultaneously low homogeneously spread turbulence intensity. Additionally, the contraction length should be kept as short as possible in order to reduce the spatial and the fabrication effort. Such flow conditions are attained by using Shimas function with an axial contraction ratio of 10 as considered as a reference for IFMIF. However, a one-step contraction causes a flow separation and hence the use of Shimas method requires a two-step nozzle with first a contraction ratio of 4 followed by another with 2.5 by which the axial dimensions of the nozzle increase in size. Within this article the turbulent flow within several one and two-step nozzle types are numerically analysed by means of the V2F model, which has been validated to depict the flow most accurately in a previous work. The study exhibits that an optimized one-step nozzle is capable to generate an optimal flow pattern the IFMIF lithium target requiring a significantly shorter dimension than the reference design.

  5. Effect of shocks on film cooling of a full scale turbojet exhaust nozzle having an external expansion surface

    Science.gov (United States)

    Straight, D. M.

    1979-01-01

    Cooling is one of the critical technologies for efficient design of exhaust nozzles, especially for the developing technology of nonaxisymmetric (2D) nozzles for future aircraft applications. Several promising 2D nozzle designs have external expansion surfaces which need to be cooled. Engine data are scarce, however, on nozzle cooling effectiveness in the supersonic flow environment (with shocks) that exists along external expansion surfaces. This paper will present experimental film cooling data obtained during exploratory testing with an axisymmetric plug nozzle having external expansion and installed on an afterburning turbojet engine in an altitude test facility. The data obtained shows that the shocks and local hot gas stream conditions have a marked effect on film cooling effectiveness. An existing film cooling correlation is adequate at some operating conditions but inadequate at other conditions such as in separated flow regions resulting from shock-boundary-layer interactions.

  6. Reverse Circulation Drilling Method Based on a Supersonic Nozzle for Dust Control

    Directory of Open Access Journals (Sweden)

    Dongyu Wu

    2016-12-01

    Full Text Available To reduce dust generated from drilling processes, a reverse circulation drilling method based on a supersonic nozzle is proposed. The suction performance is evaluated by the entrainment ratio. A series of preliminary laboratory experiments based on orthogonal experimental design were conducted to test the suction performance and reveal the main factors. Computational fluid dynamics (CFD were conducted to thoroughly understand the interaction mechanism of the flows. The Schlieren technique was further carried out to reveal the flow characteristic of the nozzle. The results show that the supersonic nozzle can significantly improve the reverse circulation effect. A high entrainment ratio up to 0.76 was achieved, which implied strong suction performance. The CFD results agreed well with experimental data with a maximum difference of 17%. This work presents the great potential for supersonic nozzles and reverse circulation in dust control, which is significant to protect the envrionment and people’s health.

  7. Argon bubble behavior in slide-gate tundish nozzles during continuous casting of steel slabs

    Science.gov (United States)

    Bai, Hua

    2000-10-01

    Argon injection into a tundish nozzle is an efficient and widely employed method to reduce nozzle clogging in the continuous casting process. It also affects casting operation and product quality by changing the flow pattern in the nozzle and mold. The current work combines mathematical modeling and experiments to investigate the argon bubble behavior in slide-gate nozzles and to analyze phenomena related to product defects and operational problems during the continuous casting of steel slabs. Water model experiments are performed to study bubble formation behavior, including bubble size, frequency, mode and effects of variables such as liquid velocity, gas injection flow rate, gas injection hole size and gas density. An analytical model is developed to predict the average bubble size. Argon gas bubbles are predicted to be 1--5mm. This is larger than air bubbles in water, especially at low speed. A three-dimensional finite difference model is developed to study the turbulent flow of liquid steel and argon bubble in the slide-gate nozzles. Experiments are performed on a 0.4-scale "water caster" to verify the model by comparing the model prediction with the measurements using PIV (Particle Image Velocimetry) technology. A weighted average scheme for the overall outflow is developed to quantify jet characteristics such as jet angle, jet speed, back flow zone fraction, turbulence and biased mass flow. Swirl is generated at nozzle ports. The validated model is employed to perform extensive parametric studies to investigate the effects of casting operation conditions such as gas injection, slide-gate orientation, casting speed, gate opening and bubble size and nozzle port design including port angle and port shape. The interrelated effects of nozzle clogging, argon injection, tundish bath depth, slide gate opening and nozzle bore diameter on the flow rate and pressure in tundish nozzles are quantified using an inverse model, based on interpolation of the numerical

  8. Aerospike Nozzle for Rotating Detonation Engine Application

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal presents a graduate MS research thesis on improving the efficiency of rotating detonation engines by using aerospike nozzle technologies. A rotating...

  9. Integrated Composite Rocket Nozzle Extension Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ORBITEC proposes to develop and demonstrate an Integrated Composite Rocket Nozzle Extension (ICRNE) for use in rocket thrust chambers. The ICRNE will utilize an...

  10. Integrated Composite Rocket Nozzle Extension, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — ORBITEC proposes to develop and demonstrate an Integrated Composite Rocket Nozzle Extension (ICRNE) for use in rocket thrust chambers. The ICRNE will utilize an...

  11. Self-Adjusting Choke For Nozzle

    Science.gov (United States)

    Morrison, Andrew D.

    1991-01-01

    Self-adjusting choke for nozzle enables issuing stream of liquid to remain coherent, despite fluctuations in flow, along greater distance than possible with same nozzle without choke. Flexible membrane with slanted orifices deforms according to upstream pressure in flowing liquid. Advantageous for firefighting, making it possible to direct more concentrated flow of water at flame or hotspot. Also used in mining and for transferring liquids.

  12. In-nozzle flow and spray characteristics for mineral diesel, Karanja, and Jatropha biodiesels

    International Nuclear Information System (INIS)

    Agarwal, Avinash Kumar; Som, Sibendu; Shukla, Pravesh Chandra; Goyal, Harsh; Longman, Douglas

    2015-01-01

    Highlights: • In-nozzle flow characterization for biodiesel sprays. • Comparison of experimental spray parameters and nozzle hole simulations. • Effect of Karanja and Jatropha biodiesel on in-nozzle cavitation. • Cavitation formation investigation with diesel and biodiesels. • Nozzle hole outlet fuel velocity profile determination for test fuels. - Abstract: Superior spray behavior of fuels in internal combustion engines lead to improved combustion and emission characteristics therefore it is necessary to investigate fuel spray behavior of new alternative fuels. This study discusses the evolution of the in-nozzle orifice parameters of a numerical simulation and the evolution of spray parameters of fuel spray in a constant-volume spray chamber during an experiment. This study compares mineral diesel, biodiesels (Karanja-and Jatropha-based), and their blends with mineral diesel. The results show that mineral diesel provides superior atomization and evaporation behavior compared to the biodiesel test fuels. Karanja biodiesel provides superior atomization and evaporation characteristics compared to Jatropha biodiesel. The qualitative comparison of simulation and experimental results in tandem shows that nozzle-hole design is a critical parameter for obtaining optimum spray behavior in the engine combustion chamber

  13. Manufacturing Process Developments for Regeneratively-Cooled Channel Wall Rocket Nozzles

    Science.gov (United States)

    Gradl, Paul; Brandsmeier, Will

    2016-01-01

    Regeneratively cooled channel wall nozzles incorporate a series of integral coolant channels to contain the coolant to maintain adequate wall temperatures and expand hot gas providing engine thrust and specific impulse. NASA has been evaluating manufacturing techniques targeting large scale channel wall nozzles to support affordability of current and future liquid rocket engine nozzles and thrust chamber assemblies. The development of these large scale manufacturing techniques focus on the liner formation, channel slotting with advanced abrasive water-jet milling techniques and closeout of the coolant channels to replace or augment other cost reduction techniques being evaluated for nozzles. NASA is developing a series of channel closeout techniques including large scale additive manufacturing laser deposition and explosively bonded closeouts. A series of subscale nozzles were completed evaluating these processes. Fabrication of mechanical test and metallography samples, in addition to subscale hardware has focused on Inconel 625, 300 series stainless, aluminum alloys as well as other candidate materials. Evaluations of these techniques are demonstrating potential for significant cost reductions for large scale nozzles and chambers. Hot fire testing is planned using these techniques in the future.

  14. Investigation of various nozzles configurations with respect to IFMIF and liquid walls concepts

    Energy Technology Data Exchange (ETDEWEB)

    Kakarantzas, S., E-mail: skakara@mie.uth.gr [Department of Mechanical Engineering, University of Thessaly, Athens Avenue, 38334 Volos (Greece); Knaepen, B.; Caby, M. [Statistical and Plasma Physics, Free University of Brussels, Campus de la Plaine, CP 231, Boulevard du Triomphe, Brussels 1050 (Belgium); Benos, L. [Department of Mechanical Engineering, University of Thessaly, Athens Avenue, 38334 Volos (Greece); Sarris, I. [Department of Energy Technology, Technological & Educational Institute of Athens, Ag. Spyridona 17, 12210 Egaleo (Greece); Pelekasis, N. [Department of Mechanical Engineering, University of Thessaly, Athens Avenue, 38334 Volos (Greece)

    2015-10-15

    Highlights: • Free surface liquid metal flows occur in the IFMIF and liquid walls fusion concepts. • In those applications, the liquid is foreseen to be fed via a nozzle. • The flow after the nozzle should be as uniform and stable as possible. • The selection of an appropriate nozzle is crucial in this direction. • In this context, a number of single and double reducer nozzles are examined. - Abstract: The study of liquid-metal free surface flows is of great interest in the fusion research, for example in the IFMIF and liquid walls concepts. In the IFMIF project, the main goal is to test candidate metallic materials in irradiation conditions similar to those present in a fusion reactor. More specifically, an intense neutron source will be produced by bombarding a high-speed liquid lithium target jet with two deuterium beams of 40 MeV. The source will then be used to test samples of the candidate materials. In the so called “Liquid walls” project, the use of liquid film free surface flows as plasma facing components (PFCs) is studied as an alternative to metallic plasma facing materials. The free surface PFCs could result in important advantages over solid walls, such as the minimization of corrosion defects and faster maintenance. In both concepts the feeding of the liquid film will be achieved by the use of a nozzle. The main scope of this work is to focus on the optimization of the flow uniformity that comes out from the nozzle. According to the literature, the use of nozzles based on the Shima profile formulation has been favoured to improve the film stability. Based on the above, a number of flows springing from several variations of “Shima” type nozzles are numerically investigated here with main goal to define the most optimum geometry in terms of minimizing turbulent defects and flow deformations.

  15. CT Scan of NASA Booster Nozzle

    Energy Technology Data Exchange (ETDEWEB)

    Schneberk, D; Perry, R; Thompson, R

    2004-07-27

    We scanned a Booster Nozzle for NASA with our 9 meV LINAC, AmSi panel scanner. Three scans were performed using different filtering schemes and different positions of the nozzle. The results of the scan presented here are taken from the scan which provided the best contrast and lowest noise of the three. Our inspection data shows a number of indications of voids in the outer coating of rubber/carbon. The voids are mostly on the side of the nozzle, but a few small voids are present at the ends of the nozzle. We saw no large voids in the adhesive layer between the Aluminum and the inner layer of carbon. This 3D inspection data did show some variation in the size of the adhesive layer, but none of the indications were larger than 3 pixels in extent (21 mils). We have developed a variety of contour estimation and extraction techniques for inspecting small spaces between layers. These tools might work directly on un-sectioned nozzles since the circular contours will fit with our tools a little better. Consequently, it would be useful to scan a full nozzle to ensure there are no untoward degradations in data quality, and to see if our tools would work to extract the adhesive layer.

  16. Influence of Nozzle Exit Conditions on the Near-Field Development of High Subsonic and Underexpanded Axisymmetric Jets

    Directory of Open Access Journals (Sweden)

    Miles T. Trumper

    2018-03-01

    Full Text Available Detailed knowledge of jet plume development in the near-field (the first 10–15 nozzle exit diameters for a round jet is important in aero-engine propulsion system design, e.g., for jet noise and plume infrared (IR signature assessment. Nozzle exit Mach numbers are often high subsonic but improperly expanded (e.g., shock-containing plumes also occur; high Reynolds numbers (O (106 are typical. The near-field is obviously influenced by nozzle exit conditions (velocity/turbulence profiles so knowledge of exit boundary layer characteristics is desirable. Therefore, an experimental study was carried out to provide detailed data on nozzle inlet and exit conditions and near-field development for convergent round nozzles operated at Nozzle Pressure Ratios (NPRs corresponding to high subsonic and supersonic (underexpanded jet plumes. Both pneumatic probe and Laser Doppler Anemometry (LDA measurements were made. The data revealed that internal nozzle acceleration led to a dramatic reduction in wall boundary layer thickness and a more laminar-like profile shape. The addition of a parallel wall extension to the end of the nozzle allowed the boundary layer to return to a turbulent state, increasing its thickness, and removing vena contracta effects. Differences in nozzle exit boundary layers exerted a noticeable influence but only in the first few diameters of plume development. The addition of the exit extension removed the vena contracta effects of the convergence only design. At underexpanded NPRs, this change to nozzle geometry modified the shock cell pattern and shortened the potential core length of the jet.

  17. Changing patterns of serological testing for celiac disease in Latvia.

    Science.gov (United States)

    Leja, Marcis; Kojalo, Una; Frickauss, Gunars; Bandere, Biruta; Gavars, Didzis; Boka, Viesturs

    2011-06-01

    A number of recent guidelines have discouraged the use of the old anti-gliadin tests for the detection of celiac disease; tissue transglutaminase IgA (tTGA) and anti-endomysial (EMA) tests are recommended instead. Our aim was to evaluate how the current recommendations have been applied in real practice. The secondary aim was to evaluate the positivity rates provided by different test types. We analyzed the number of celiac disease tests [anti-gliadin IgA (AGA), anti-gliadin IgG (AGG), tTGA and EMA] performed by the largest laboratory in Latvia. The analysis was performed on a yearly basis for the period between 2004 and 2009. Additionally, we analyzed the percentage of the positive test results for each of the tests. The number of patients being tested for celiac disease constantly increased, with the average annual growth of 16.1%; this trend was similar both in children and in adults. The majority of patients (62.6%) were tested with anti-gliadin tests only; 27.7% were tested with either tTGA or EMA, while 9.7% were tested by a combination of the above groups. There was a substantial difference in the positivity rates of the different tests from 0.94% for EMA to 21.8% for AGG. Substantial differences were also present between various manufacturers' products. The current guidelines and the published evidence on the proper use of serological tests for celiac disease have been slow to be applied in clinical practice; more intensive education campaigns and change in reimbursement systems could improve the situation. Nevertheless, more clinicians in Latvia are checking patients for celiac disease; this suggests an overall increased awareness.

  18. Wind Tunnel Model Design for Sonic Boom Studies of Nozzle Jet Flows with Shock Interactions

    Science.gov (United States)

    Cliff, Susan E.; Denison, Marie; Moini-Yekta, Shayan; Morr, Donald E.; Durston, Donald A.

    2016-01-01

    NASA and the U.S. aerospace industry are performing studies of supersonic aircraft concepts with low sonic boom pressure signatures. The computational analyses of modern aircraft designs have matured to the point where there is confidence in the prediction of the pressure signature from the front of the vehicle, but uncertainty remains in the aft signatures due to boundary layer and nozzle exhaust jet effects. Wind tunnel testing without inlet and nozzle exhaust jet effects at lower Reynolds numbers than in-flight make it difficult to accurately assess the computational solutions of flight vehicles. A wind tunnel test in the NASA Ames 9- by 7-Foot Supersonic Wind Tunnel is planned for February 2016 to address the nozzle jet effects on sonic boom. The experiment will provide pressure signatures of test articles that replicate waveforms from aircraft wings, tails, and aft fuselage (deck) components after passing through cold nozzle jet plumes. The data will provide a variety of nozzle plume and shock interactions for comparison with computational results. A large number of high-fidelity numerical simulations of a variety of shock generators were evaluated to define a reduced collection of suitable test models. The computational results of the candidate wind tunnel test models as they evolved are summarized, and pre-test computations of the final designs are provided.

  19. Measuring Spray Droplet Size from Agricultural Nozzles Using Laser Diffraction

    Science.gov (United States)

    Fritz, Bradley K.; Hoffmann, W. Clint

    2016-01-01

    When making an application of any crop protection material such as an herbicide or pesticide, the applicator uses a variety of skills and information to make an application so that the material reaches the target site (i.e., plant). Information critical in this process is the droplet size that a particular spray nozzle, spray pressure, and spray solution combination generates, as droplet size greatly influences product efficacy and how the spray moves through the environment. Researchers and product manufacturers commonly use laser diffraction equipment to measure the spray droplet size in laboratory wind tunnels. The work presented here describes methods used in making spray droplet size measurements with laser diffraction equipment for both ground and aerial application scenarios that can be used to ensure inter- and intra-laboratory precision while minimizing sampling bias associated with laser diffraction systems. Maintaining critical measurement distances and concurrent airflow throughout the testing process is key to this precision. Real time data quality analysis is also critical to preventing excess variation in the data or extraneous inclusion of erroneous data. Some limitations of this method include atypical spray nozzles, spray solutions or application conditions that result in spray streams that do not fully atomize within the measurement distances discussed. Successful adaption of this method can provide a highly efficient method for evaluation of the performance of agrochemical spray application nozzles under a variety of operational settings. Also discussed are potential experimental design considerations that can be included to enhance functionality of the data collected. PMID:27684589

  20. Pattern Generator for Bench Test of Digital Boards

    Science.gov (United States)

    Berkun, Andrew C.; Chu, Anhua J.

    2012-01-01

    All efforts to develop electronic equipment reach a stage where they need a board test station for each board. The SMAP digital system consists of three board types that interact with each other using interfaces with critical timing. Each board needs to be tested individually before combining into the integrated digital electronics system. Each board needs critical timing signals from the others to be able to operate. A bench test system was developed to support test of each board. The test system produces all the outputs of the control and timing unit, and is delivered much earlier than the timing unit. Timing signals are treated as data. A large file is generated containing the state of every timing signal at any instant. This file is streamed out to an IO card, which is wired directly to the device-under-test (DUT) input pins. This provides a flexible test environment that can be adapted to any of the boards required to test in a standalone configuration. The problem of generating the critical timing signals is then transferred from a hardware problem to a software problem where it is more easily dealt with.

  1. Revealing the surface pattern of medieval pattern welded iron objects - etching tests conducted on reconstructed composites

    Czech Academy of Sciences Publication Activity Database

    Thiele, Á.; Hošek, Jiří; Haramza, M.; Török, B.

    2014-01-01

    Roč. 25, č. 1 (2014), s. 18-24 ISSN 1805-7241 R&D Projects: GA ČR GAP405/12/2289 Institutional support: RVO:67985912 Keywords : etching * pattern welding * phosphoric iron * archaeometallurgy Subject RIV: AC - Archeology, Anthropology, Ethnology

  2. Computational study of performance characteristics for truncated conical aerospike nozzles

    Science.gov (United States)

    Nair, Prasanth P.; Suryan, Abhilash; Kim, Heuy Dong

    2017-12-01

    Aerospike nozzles are advanced rocket nozzles that can maintain its aerodynamic efficiency over a wide range of altitudes. It belongs to class of altitude compensating nozzles. A vehicle with an aerospike nozzle uses less fuel at low altitudes due to its altitude adaptability, where most missions have the greatest need for thrust. Aerospike nozzles are better suited to Single Stage to Orbit (SSTO) missions compared to conventional nozzles. In the current study, the flow through 20% and 40% aerospike nozzle is analyzed in detail using computational fluid dynamics technique. Steady state analysis with implicit formulation is carried out. Reynolds averaged Navier-Stokes equations are solved with the Spalart-Allmaras turbulence model. The results are compared with experimental results from previous work. The transition from open wake to closed wake happens in lower Nozzle Pressure Ratio for 20% as compared to 40% aerospike nozzle.

  3. Experimental and analytical investigation of axisymmetric supersonic cruise nozzle geometry at Mach numbers from 0.60 to 1.30

    Science.gov (United States)

    Carson, G. T., Jr.; Lee, E. E., Jr.

    1981-01-01

    Quantitative pressure and force data for five axisymmetric boattail nozzle configurations were examined. These configurations simulate the variable-geometry feature of a single nozzle design operating over a range of engine operating conditions. Five nozzles were tested in the Langley 16-Foot Transonic Tunnel at Mach numbers from 0.60 to 1.30. The experimental data were also compared with theoretical predictions.

  4. Robotic cleaning of radwaste tank nozzles

    International Nuclear Information System (INIS)

    Boughman, G.; Jones, S.L.

    1992-01-01

    The Susquehanna radwaste processing system includes two reactor water cleanup phase separator tanks and one waste sludge phase separator tank. A system of educator nozzles and associated piping is used to provide mixing in the tanks. The mixture pumped through the nozzles is a dense resin-and-water slurry, and the nozzles tend to plug up during processing. The previous method for clearing the nozzles had been for a worker to enter the tanks and manually insert a hydrolaser into each nozzle, one at a time. The significant radiation exposure and concern for worker safety in the tank led the utility to investigate alternate means for completing this task. The typical tank configuration is shown in a figure. The initial approach investigated was to insert a manipulator arm in the tank. This arm would be installed by workers and then teleoperated from a remote control station. This approach was abandoned because of several considerations including educator location and orientation, excessive installation time, and cost. The next approach was to use a mobile platform that would operate on the tank floor. This approach was selected as being the most feasible solution. After a competitive selection process, REMOTEC was selected to provide the mobile platform. Their proposal was based on the commercial ANDROS Mark 5 platform

  5. Nozzle dam having a unitary plug

    Science.gov (United States)

    Veronesi, L.; Wepfer, R.M.

    1992-12-15

    Apparatus for sealing the primary-side coolant flow nozzles of a nuclear steam generator is disclosed. The steam generator has relatively small diameter manway openings for providing access to the interior of the steam generator including the inside surface of each nozzle, the manway openings having a diameter substantially less than the inside diameter of each nozzle. The apparatus includes a bracket having an outside surface for matingly sealingly engaging the inside surface of the nozzle. The bracket also has a plurality of openings longitudinally therethrough and a plurality of slots transversely therein in communication with each opening. A plurality of unitary plugs sized to pass through the manway opening are matingly sealingly disposed in each opening of the bracket for sealingly plugging each opening. Each plug includes a plurality of arms operable to engage the slots of the bracket for connecting each plug to the bracket, so that the nozzle is sealed as the plugs seal the openings and are connected to the bracket. 16 figs.

  6. A Studentized Permutation Test for the Comparison of Spatial Point Patterns

    DEFF Research Database (Denmark)

    Hahn, Ute

    A new test is proposed for the hypothesis that two (or more) observed point patterns are realizations of the same spatial point process model. To this end, the point patterns are divided into disjoint quadrats, on each of which an estimate of Ripley's K-function is calculated. The two groups...... of empirical K-functions are compared by a permutation test using a studentized test statistic. The proposed test performs convincingly in terms of empirical level and power in a simulation study, even for point patterns where the K-function estimates on neighboring subsamples are not strictly exchangeable...

  7. Design of high pressure waterjet nozzles

    Science.gov (United States)

    Mazzoleni, Andre P.

    1994-10-01

    The Hydroblast Research Cell at Marshall Space Flight Center is used to investigate the use of high pressure waterjets to strip paint, grease, adhesive and thermal spray coatings from various substrates. Current methods of cleaning often use ozone depleting chemicals (ODC) such as chlorinated solvents. High pressure waterjet cleaning has proven to be a viable alternative to the use of solvents. A popular method of waterjet cleaning involves the use of a rotating, multijet, high pressure water nozzle which is robotically controlled. This method enables rapid cleaning of a large area, but problems such as incomplete coverage and damage to the substrate from the waterjet have been observed. This report summarizes research consisting of identifying and investigating the basic properties of rotating, multijet, high pressure water nozzles, and how particular designs and modes of operation affect such things as stripping rate, standoff distance and completeness of coverage. The study involved computer simulations, an extensive literature review, and experimental studies of different nozzle designs.

  8. Li/Li2 supersonic nozzle beam

    International Nuclear Information System (INIS)

    Wu, C.Y.R.; Crooks, J.B.; Yang, S.C.; Way, K.R.; Stwalley, W.C.

    1977-01-01

    The characterization of a lithium supersonic nozzle beam was made using spectroscopic techniques. It is found that at a stagnation pressure of 5.3 kPa (40 torr) and a nozzle throat diameter of 0.4 mm the ground state vibrational population of Li 2 can be described by a Boltzmann distribution with T/sub v/ = 195 +- 30 0 K. The rotational temperature is found to be T/sub r/ = 70 +- 20 0 K by band shape analysis. Measurements by quadrupole mass spectrometer indicates that approximately 10 mole per cent Li 2 dimers are formed at an oven body temperature of 1370 0 K n the supersonic nozzle expansion. This measured mole fraction is in good agreement with the existing dimerization theory

  9. SSME Seal Test Program: Test results for sawtooth pattern damper seal

    Science.gov (United States)

    Childs, D. W.

    1986-01-01

    Direct and transverse force coefficients for 11, sawtooth-pattern, and damper-seal configurations were examined. The designation damper seal uses a deliberately roughened stator and smooth rotor to increase the net damping force developed by a seal. The designation sawtooth-pattern refers to a stator roughness pattern. The sawtooth pattern yields axial grooves in the stator which are interrupted by spacer elements which act as flow constrictions or dams. All seals use the same smooth rotor and have the same, constant, minimum clearance. The stators examined the consequences of changes in the following design parameters: (1) axial-groove depth; (2) number of teeth: (3) number of sawtooth sections; (4) number of spacer elements; (5) dam width; (6) axially aligned sawtooth sections versus axially-staggered sawtooth sections; and (7) groove geometry. It is found that none of the sawtooth-pattern seal performs as well as the best round-hole-pattern seal. Maximum damping configurations for the sawtooth and round-hole-pattern stators have comparable stiffness performance. Several of the sawtooth pattern stators outperformed the best round-hole pattern seal.

  10. Combustor nozzles in gas turbine engines

    Science.gov (United States)

    Johnson, Thomas Edward; Keener, Christopher Paul; Stewart, Jason Thurman; Ostebee, Heath Michael

    2017-09-12

    A micro-mixer nozzle for use in a combustor of a combustion turbine engine, the micro-mixer nozzle including: a fuel plenum defined by a shroud wall connecting a periphery of a forward tube sheet to a periphery of an aft tubesheet; a plurality of mixing tubes extending across the fuel plenum for mixing a supply of compressed air and fuel, each of the mixing tubes forming a passageway between an inlet formed through the forward tubesheet and an outlet formed through the aft tubesheet; and a wall mixing tube formed in the shroud wall.

  11. Lightweight Nozzle Extension for Liquid Rocket Engines Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The ARES J-2X requires a large nozzle extension. Currently, a metallic nozzle extension is being considered with carbon-carbon composite as a backup. In Phase 1,...

  12. Turbocharger with variable nozzle having vane sealing surfaces

    Science.gov (United States)

    Arnold, Philippe [Hennecourt, FR; Petitjean, Dominique [Julienrupt, FR; Ruquart, Anthony [Thaon les Vosges, FR; Dupont, Guillaume [Thaon les Vosges, FR; Jeckel, Denis [Thaon les Vosges, FR

    2011-11-15

    A variable nozzle for a turbocharger includes a plurality of vanes rotatably mounted on a nozzle ring and disposed in a nozzle flow path defined between the nozzle ring and an opposite nozzle wall. Either or both of the faces of the nozzle ring and nozzle wall include(s) at least one step that defines sealing surfaces positioned to be substantially abutted by airfoil surfaces of the vanes in the closed position of the vanes and to be spaced from the airfoil surfaces in positions other than the closed position. This substantial abutment between the airfoil surfaces and the sealing surfaces serves to substantially prevent exhaust gas from leaking past the ends of the airfoil portions. At the same time, clearances between the nozzle ring face and the end faces of the airfoil portions can be sufficiently large to prevent binding of the vanes under all operating conditions.

  13. Development of cooling techniques for induction heating stress improvement of reactor recirculation inlet nozzle

    International Nuclear Information System (INIS)

    Takahashi, Shirou; Shiina, Kouji; Nihei, Kenichi; Kanno, Satoshi; Hayashi, Shoji; Ootaka, Minoru

    2007-01-01

    Induction heating stress improvement (IHSI) has been used in nuclear power plants to reduce residual stress in welded sections of pipes by generating temperature differences between the inner and outer surfaces of the pipes. The outer metal surface is heated by induction heating, and the inner surface is cooled by flowing water. However, it is difficult to obtain a sufficient temperature gradient in the places where the flow stagnates and the heat transfer cannot be enhanced. In the present study, we developed cooling techniques for a reactor recirculation inlet nozzle with a closed end and very narrow annular channel. Computational fluid dynamics (CFD) analyses, half-scale tests, and full-scale tests were conducted to investigate the flow and cooling characteristics. One million grids of a reactor recirculation inlet nozzle model were used for the CFD analysis. Detached eddy simulation (DES) was used as the turbulence model to evaluate the unsteady phenomena of the jet flow and temperature distribution. The experimental apparatuses used for the half-scale tests were made of acryl to visualize the flow, and heat transfer coefficients were measured at the welded portions. In the full-scale tests, the temperature differences between the inner and outer surface of the recirculation inlet nozzle were measured, and reduction of the residual stress was verified. It was confirmed that the jet flow moved up and down when to jet nozzles were arranged symmetrically. The turbulence due to self-sustained jet fluctuation was effective for uniform cooling in the reactor recirculation inlet nozzle. The flow did not stagnate around the welded portion. The heat transfer coefficients at the welded portion were evaluated using an equation with Reynolds and Nusselt numbers in half-scale tests. It was also verified in full scale tests that the temperature difference between the inner and outer surfaces of the recirculation inlet nozzle was approximately 490degC, which satisfied the

  14. Effect of airstream velocity on mean drop diameters of water sprays produced by pressure and air atomizing nozzles

    Science.gov (United States)

    Ingebo, R. D.

    1977-01-01

    A scanning radiometer was used to determine the effect of airstream velocity on the mean drop diameter of water sprays produced by pressure atomizing and air atomizing fuel nozzles used in previous combustion studies. Increasing airstream velocity from 23 to 53.4 meters per second reduced the Sauter mean diameter by approximately 50 percent with both types of fuel nozzles. The use of a sonic cup attached to the tip of an air assist nozzle reduced the Sauter mean diameter by approximately 40 percent. Test conditions included airstream velocities of 23 to 53.4 meters per second at 293 K and atmospheric pressure.

  15. A Comparative Study of Nozzle/Diffuser Micropumps with Novel Valves

    Directory of Open Access Journals (Sweden)

    Jin-Cherng Shyu

    2012-02-01

    Full Text Available This study conducts an experimental study concerning the improvement of nozzle/diffuser micropump design using some novel no-moving-part valves. A total of three micropumps, including two enhancement structures having two-fin or obstacle structure and one conventional micro nozzle/diffuser design, are made and tested in this study. It is found that dramatic increase of the pressure drops across the designed micro nozzles/diffusers are seen when the obstacle or fin structure is added. The resultant maximum flow rates are 47.07 mm3/s and 53.39 mm3/s, respectively, for the conventional micro nozzle/diffuser and the added two-fin structure in micro nozzle/diffuser operated at a frequency of 400 Hz. Yet the mass flow rate for two-fin design surpasses that of conventional one when the frequency is below 425 Hz but the trend is reversed with a further increase of frequency. This is because the maximum efficiency ratio improvement for added two-fin is appreciably higher than the other design at a lower operating frequency. In the meantime, despite the efficiency ratio of the obstacle structure also reveals a similar trend as that of two-fin design, its significant pressure drop (flow resistance had offset its superiority at low operating frequency, thereby leading to a lesser flow rate throughout the test range.

  16. Improvement of combustion in a direct injection diesel engine by micro-hole nozzle; Micro hole nozzle wo mochiita chokusetsu funshashiki diesel kikan no nensho kaizen

    Energy Technology Data Exchange (ETDEWEB)

    Murata, M. [Keio University, Tokyo (Japan); Kobori, S. [Tokyo Institute of Technology, Tokyo (Japan); Iida, N. [Keio University, Tokyo (Japan). Faculty of Science and Technology

    2000-07-25

    In an attempt to promote the atomization of fuel spray and the mixing of fuel and air in diesel engines, a micro-hole nozzle which has orifices with a diameter smaller than 0.10mm was developed. In this study, the combustion tests were carried out using a single cylinder diesel engine equipped with a micro-hole nozzle and a common rail type high-pressure fuel injection system. A comparison with the results of a conventional nozzle experiment showed that the peak of initial premixed combustion increased, but the peak of diffusion combustion decreased. As a result, when nozzle orifice diameter become small from {phi} 0.15 mm to {phi} 0.10 mm, the combustion was accompanied by smokeless with the same levels of NO{sub x} emission and fuel economy. And results of a comparison the toroidal type chamber with the shallow dish type chamber revealed that the optimization of combustion chamber is necessary for the increase of the injection stage with increasing of the number of nozzle orifice. If an orifice diameter becomes {phi} 0.06 mm, the diffusion combustion can not be observed and the combustion is formed of only premixed combustion. The combustion in the case of {phi} 0.06 mm was accompanied with the drastic deterioration of fuel economy, smoke and HC with all over load. But the micro-hole nozzle has a potential for the formation of the lean and homogeneous premixed mixture until the fuel-air mixture ignites. (author)

  17. CFD Analysis On The Performance Of Wind Turbine With Nozzles

    Directory of Open Access Journals (Sweden)

    Chunkyraj Kh

    2015-08-01

    Full Text Available In this paper an effort has been made in dealing with fluid characteristic that enters a converging nozzle and analysis of the nozzle is carried out using Computational Fluid Dynamics package ANSYS WORKBENCH 14.5. The paper is the continuation of earlier work Analytical and Experimental performance evaluation of Wind turbine with Nozzles. First the CFD analysis will be carried out on nozzle in-front of wind turbine where streamline velocity at the exit volume flow rate in the nozzle and pressure distribution across the nozzle will be studied. Experiments were conducted on the Wind turbine with nozzles and the corresponding power output at different air speed and different size of nozzles were calculated. Different shapes and dimensions with special contours and profiles of nozzles were studied. It was observed that the special contour nozzles have superior outlet velocity and low pressure at nozzle exit the design has maximum Kinetic energy. These indicators conclude that the contraction designed with the new profile is a good enhancing of the nozzle performance.

  18. Design and Analysis of Elliptical Nozzle in AJM Process using ...

    African Journals Online (AJOL)

    The common nozzle shape presently used in AJM machining process is rectangle and circular shape nozzle which gives a low flow rate and further demands on decreasing the material removal rate (MRR), so this research mainly focuses on designing nozzle geometry to improve flow rate and MRR in AJM machining ...

  19. A fundamental study of a variable critical nozzle flow

    International Nuclear Information System (INIS)

    Kim, Jea Hyung; Kim, Heuy Dong; Park, Kyung Am

    2003-01-01

    The mass flow rate of gas flow through critical nozzle depends on the nozzle supply conditions and the cross-sectional area at the nozzle throat. In order that the critical nozzle can be operated at a wide range of supply conditions, the nozzle throat diameter should be controlled to change the flow passage area. This can be achieved by means of a variable critical nozzle. In the present study, both experimental and computational works are performed to develop variable critical nozzle. A cone-cylinder with a diameter of d is inserted into conventional critical nozzle. It can move both upstream and downstream, thereby changing the cross-sectional area of the nozzle throat. Computational work using the axisymmetric, compressible Navier-Stokes equations is carried out to simulate the variable critical nozzle flow. An experiment is performed to measure the mass flow rate through variable critical nozzle. The present computational results are in close agreement with measured ones. The boundary layer displacement and momentum thickness are given as a function of Reynolds number. An empirical equation is obtained to predict the discharge coefficient of variable critical nozzle

  20. Integrated Ceramic Matrix Composite and Carbon/Carbon Structures for Large Rocket Engine Nozzles and Nozzle Extensions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Low-cost access to space demands durable, cost-effective, efficient, and low-weight propulsion systems. Key components include rocket engine nozzles and nozzle...

  1. Effects of Analytical and Holistic Scoring Patterns on Scorer Reliability in Biology Essay Tests

    Science.gov (United States)

    Ebuoh, Casmir N.

    2018-01-01

    Literature revealed that the patterns/methods of scoring essay tests had been criticized for not being reliable and this unreliability is more likely to be more in internal examinations than in the external examinations. The purpose of this study is to find out the effects of analytical and holistic scoring patterns on scorer reliability in…

  2. Fabrication of Microglass Nozzle for Microdroplet Jetting

    Directory of Open Access Journals (Sweden)

    Dan Xie

    2015-02-01

    Full Text Available An ejection aperture nozzle is the essential part for all microdrop generation techniques. The diameter size, the flow channel geometry, and fluid impedance are the key factors affecting the ejection capacity. A novel low-cost fabrication method of microglass nozzle involving four steps is developed in this work. In the first heating step, the glass pipette is melted and pulled. Then, the second heating step is to determine the tip cone angle and modify the flow channel geometry. The desired included angle is usually of 30~45 degrees. Fine grind can determine the exact diameter of the hole. Postheating step is the final process and it can reduce the sharpness of the edges of the hole. Micronozzles with hole diameters varying from 30 to 100 µm are fabricated by the homemade inexpensive and easy-to-operate setup. Hydrophobic treating method of microglass nozzle to ensure stable and accurate injection is also introduced in this work. According to the jetting results of aqueous solution, UV curing adhesive, and solder, the fabricated microglass nozzle can satisfy the need of microdroplet jetting of multimaterials.

  3. Remotely installed steam generator nozzle dam system

    International Nuclear Information System (INIS)

    Mc Donald, F.X.; Weisel, E.M.; Schukei, G.E.

    1990-01-01

    This patent describes a method for remotely installing a dam unit in a nozzle or a nuclear steam generator head, the head including a manway. It comprises: mounting an articulated manipulator to an internal surface of the head, the manipulator having a free end which carries a jaw member; positioning the manipulator so that the jaw member is adjacent the manway and substantially on the manway axis; passing a first dam segment through the manway and attaching the jaw member to the first segment; positioning the manipulator so that the jaw member holds the first dam segment on one side of the manway axis; passing a second dam segment through the manway into engagement with the first dam segment to form a dam subassembly; translating the manipulator through the head until the dam subassembly is adjacent the nozzle; advancing the jaw member toward the nozzle until the cam subassembly is positioned substantially at the desired location of the dam unit with respect to the nozzle; and deploying the manipulator to install dam support structure between the dam subassembly and the steam generator, thereby forming an installed dam unit

  4. Clamp and Gas Nozzle for TIG Welding

    Science.gov (United States)

    Gue, G. B.; Goller, H. L.

    1982-01-01

    Tool that combines clamp with gas nozzle is aid to tungsten/inert-gas (TIG) welding in hard-to-reach spots. Tool holds work to be welded while directing a stream of argon gas at weld joint, providing an oxygen-free environment for tungsten-arc welding.

  5. Post-Hoc Pattern-Oriented Testing and Tuning of an Existing Large Model

    DEFF Research Database (Denmark)

    Topping, Christopher John; Dalkvist, Trine; Grimm, Volker

    2012-01-01

    Pattern-oriented modeling (POM) is a general strategy for modeling complex systems. In POM, multiple patterns observed at different scales and hierarchical levels are used to optimize model structure, to test and select sub-models of key processes, and for calibration. So far, POM has been used...... environment closely. We therefore conclude that post-hoc POM is a useful and viable way to test a highly complex simulation model, but also warn against the dangers of over-fitting to real world patterns that lack details in their explanatory driving factors. To overcome some of these obstacles we suggest...... for developing new models and for models of low to moderate complexity. It remains unclear, though, whether the basic idea of POM to utilize multiple patterns, could also be used to test and possibly develop existing and established models of high complexity. Here, we use POM to test, calibrate, and further...

  6. Experimental study of the effects of exhaust plume and nozzle length on transonic and supersonic axisymmetric base flows : An experimental study

    NARCIS (Netherlands)

    van Gent, P.L.; Payanda (Student TUDelft), Qais; Brust (Student TUDelft), Steve; van Oudheusden, B.W.; Schrijer, F.F.J.

    2017-01-01

    PIV measurements have been carried out to study the effect of exhaust plume and nozzle length on the flow topology and mean pressure distribution of axisymmetric base flows at freestream Mach numbers 0.76 and 2.20. Four different nozzle lengths with and without exhaust plume have been tested. The

  7. An Analysis of Random Student Drug Testing Policies and Patterns of Practice In Virginia Public Schools

    OpenAIRE

    Lineburg, Mark Young

    2005-01-01

    An Analysis of Random Student Drug Testing Policies and Patterns of Practice In Virginia Public Schools Mark Y. Lineburg Abstract There were two purposes to this study. First, the study was designed to determine which Virginia public school districts have articulated policies that govern random drug testing of students and if school districtsâ policies aligned with U.S. Supreme Court standards and Virginia statutes. The second purpose was to ascertain the patterns of pract...

  8. Distribuição volumétrica e espectro de gotas de pontas de pulverização de baixa deriva Volumetric distribution and droplet spectrum by low drift spray nozzles

    Directory of Open Access Journals (Sweden)

    R.G. Viana

    2010-06-01

    Full Text Available Objetivou-se neste trabalho avaliar a distribuição volumétrica e o espectro de gotas das pontas de pulverização de baixa deriva TTI110015, AI110015 e AVI11001 sob diferentes condições operacionais. A distribuição volumétrica foi determinada em bancada de ensaios padronizada analisando o coeficiente de variação (CV% de uma barra simulada em computador, utilizando pressões de 200, 300 e 400 kPa, altura de 30, 40 e 50 cm em relação à bancada e espaçamento entre pontas de 40 a 100 cm. O espectro de gotas foi produzido utilizando-se apenas água como calda em um analisador de partículas em meio aquoso, nas pressões de 200, 300 e 400 kPa. Foram avaliados o DMV, a porcentagem de gotas com diâmetro inferior a 100 µm (%100 µm e a amplitude relativa (AR. As pontas proporcionaram perfil descontínuo nas pressões de 300 e 400 kPa e uniforme a 200 kPa. Na pressão de 200 kPa, as pontas foram adequadas apenas para aplicação em faixa, e a 300 e 400 kPa, apenas para área total. Ocorreu menor CV (abaixo de 7% com a maior pressão de trabalho e menor espaçamento entre pontas. À medida que se aumentou a pressão de trabalho, reduziu-se o DMV. As pontas TTI110015 e AI110015 em todas as pressões e a ponta AVI11001 na pressão de 200 kPa produziram gotas extremamente grossas e gotas grossas nas pressões de 300 e 400 kPa apenas para a ponta AVI11001. As pontas proporcionaram baixos valores de amplitude relativa (AR e gotas de tamanho uniforme, bem como produziram baixa porcentagem de gotas menores que 100 µm, principalmente TTI110015 e AI110015, com menor risco de deriva.This study aimed to evaluate the distribution profile and droplet spectra of low drift spray nozzles TTI110015, AI110015 and AI11001 under different operational conditions. The volumetric distribution was determined on a test table (patternator, by analyzing the coefficient of variation (CV of a computer simulated spraying boom at pressures 200, 300 and 400 kPa, height

  9. Neural Network Based Recognition of Signal Patterns in Application to Automatic Testing of Rails

    Directory of Open Access Journals (Sweden)

    Tomasz Ciszewski

    2006-01-01

    Full Text Available The paper describes the application of neural network for recognition of signal patterns in measuring data gathered by the railroad ultrasound testing car. Digital conversion of the measuring signal allows to store and process large quantities of data. The elaboration of smart, effective and automatic procedures recognizing the obtained patterns on the basisof measured signal amplitude has been presented. The test shows only two classes of pattern recognition. In authors’ opinion if we deliver big enough quantity of training data, presented method is applicable to a system that recognizes many classes.

  10. Design and Analysis of Fused Deposition Modeling 3D Printer Nozzle for Color Mixing

    Directory of Open Access Journals (Sweden)

    Shanling Han

    2017-01-01

    Full Text Available Fused deposition modeling (FDM has been one of the most widely used rapid prototyping (RP technologies leading to the increase in market attention. Obviously it is desirable to print 3D objects; however, existing FDM printers are restricted to printing only monochrome objects because of the entry-level nozzle structure, and literature on the topic is also sparse. In this paper, the CAD model of the nozzle is established first by UG (Unigraphics NX software to show the structure of fused deposition modeling 3D printer nozzle for color mixing. Second, the flow channel model of the nozzle is extracted and simplified. Then, the CAD and finite element model are established by UG and ICEM CFD software, respectively, to prepare for the simulation. The flow field is simulated by Fluent software. The nozzle’s suitable temperature at different extrusion speeds is obtained, and the reason for the blockage at the intersection of the heating block is revealed. Finally, test verification of the nozzle is performed, which can produce mixed-color artifacts stably.

  11. Fuel density effect on near nozzle flow field in small laminar coflow diffusion flames

    KAUST Repository

    Xiong, Yuan

    2015-01-01

    Flow characteristics in small coflow diffusion flames were investigated with a particular focus on the near-nozzle region and on the buoyancy force exerted on fuels with densities lighter and heavier than air (methane, ethylene, propane, and n-butane). The flow-fields were visualized through the trajectories of seed particles. The particle image velocimetry technique was also adopted for quantitative velocity field measurements. The results showed that the buoyancy force exerted on the fuel as well as on burnt gas significantly distorted the near-nozzle flow-fields. In the fuels with densities heavier than air, recirculation zones were formed very close to the nozzle, emphasizing the importance of the relative density of the fuel to that of the air on the flow-field. Nozzle heating influenced the near-nozzle flow-field particularly among lighter fuels (methane and ethylene). Numerical simulations were also conducted, focusing specifically on the effect of specifying inlet boundary conditions for fuel. The results showed that a fuel inlet boundary with a fully developed velocity profile for cases with long tubes should be specified inside the fuel tube to permit satisfactory prediction of the flow-field. The calculated temperature fields also indicated the importance of the selection of the location of the inlet boundary, especially in testing various combustion models that include soot in small coflow diffusion flames. © 2014 The Combustion Institute.

  12. Inelastic finite element cyclic analysis of a nozzle-to-cylinder intersection

    International Nuclear Information System (INIS)

    Barsoum, R.S.; Loomis, R.W.

    1976-01-01

    A finite element elastic-plastic and creep analysis of a nozzle-to-cylinder intersection subject to cyclic thermal shock, internal pressure, and mechanical loads is presented. The nozzle configuration is that of the intermediate heat exchanger (IHX) for the Fast Flux Test Facility (FFTF). The analysis was performed using the general purpose program MARC. Both the elastic and inelastic results of the analysis are presented. The intention of this study to analytically investigate the applicability of simplified ratchetting and creep-fatigue rules for LMFBR components, as a part of a program covering various geometries and loadings

  13. Experimental performance of three design factors for ventral nozzles for SSTOVL aircraft

    Science.gov (United States)

    Esker, Barbara S.; Perusek, Gail P.

    1992-01-01

    An experimental study of three variations of a ventral nozzle system for supersonic short-takeoff and vertical-landing (SSTOVL) aircraft was performed at the NASA LeRC Powered Lift Facility. These test results include the effects of an annular duct flow into the ventral duct, a blocked tailpipe, and a short ventral duct length. An analytical study was also performed on the short ventral duct configuration using the PARC3D computational dynamics code. Data presented include pressure losses, thrust and flow performance, internal flow visualization, and pressure distributions at the exit plane of the ventral nozzle.

  14. Calculations of the nozzle coefficient of discharge of wet steam turbine stages

    International Nuclear Information System (INIS)

    Jinling, Z.; Yinian, C.

    1989-01-01

    A method is presented for calculating the coefficient of discharge of wet steam turbine nozzles. The theoretical formulation of the problem is rigorously in accordance with the theory of two-phase wet steam expansion flow through steam turbine nozzles. The computational values are plotted as sets of curves in accordance with orthogonality test principles. They agree satisfactorily both with historical empirical data and the most recent experimental data obtained in the wet steam two-phase flow laboratory of Xian Jiaotong University. (author)

  15. Static Thrust of an Annular Nozzle with a Concave Central Base

    Science.gov (United States)

    Corson, Blake W., Jr.; Mercer, Charles E.

    1960-01-01

    A static test of an annular nozzle with a concave central base, producing a jet in which tangents to the jet streamlines at the exit converged toward a region on the axis of symmetry downstream of the exit, has indicated good thrust performance. A value of nozzle-flow coefficient only slightly less than unity indicates the internal loss to be small. Pressures on the concave central base are relatively large and positive, and a predictable portion of the total thrust of the jet is exerted on the central base.

  16. A review of methods for evaluating the fit of item score patterns on a test

    NARCIS (Netherlands)

    Meijer, R.R.; Sijtsma, Klaas

    1999-01-01

    Methods are discussed that can be used to investigate the fit of an item score pattern to a test model. Model-based tests and personality inventories are administered to more than 100 million people a year and, as a result, individual fit is of great concern. Item Response Theory (IRT) modeling and

  17. A Psychometric Review of Norm-Referenced Tests Used to Assess Phonological Error Patterns

    Science.gov (United States)

    Kirk, Celia; Vigeland, Laura

    2014-01-01

    Purpose: The authors provide a review of the psychometric properties of 6 norm-referenced tests designed to measure children's phonological error patterns. Three aspects of the tests' psychometric adequacy were evaluated: the normative sample, reliability, and validity. Method: The specific criteria used for determining the psychometric…

  18. Study on high throughput nanomanufacturing of photopatternable nanofibers using tube nozzle electrospinning with multi-tubes and multi-nozzles

    Science.gov (United States)

    Fang, Sheng-Po; Jao, PitFee; Senior, David E.; Kim, Kyoung-Tae; Yoon, Yong-Kyu

    2017-12-01

    High throughput nanomanufacturing of photopatternable nanofibers and subsequent photopatterning is reported. For the production of high density nanofibers, the tube nozzle electrospinning (TNE) process has been used, where an array of micronozzles on the sidewall of a plastic tube are used as spinnerets. By increasing the density of nozzles, the electric fields of adjacent nozzles confine the cone of electrospinning and give a higher density of nanofibers. With TNE, higher density nozzles are easily achievable compared to metallic nozzles, e.g. an inter-nozzle distance as small as 0.5 cm and an average semi-vertical repulsion angle of 12.28° for 8-nozzles were achieved. Nanofiber diameter distribution, mass throughput rate, and growth rate of nanofiber stacks in different operating conditions and with different numbers of nozzles, such as 2, 4 and 8 nozzles, and scalability with single and double tube configurations are discussed. Nanofibers made of SU-8, photopatternable epoxy, have been collected to a thickness of over 80 μm in 240 s of electrospinning and the production rate of 0.75 g/h is achieved using the 2 tube 8 nozzle systems, followed by photolithographic micropatterning. TNE is scalable to a large number of nozzles, and offers high throughput production, plug and play capability with standard electrospinning equipment, and little waste of polymer.

  19. Carbon-Carbon Nozzle Extension Development in Support of In-Space and Upper-Stage Liquid Rocket Engines

    Science.gov (United States)

    Gradl, Paul R.; Valentine, Peter G.

    2017-01-01

    Upper stage and in-space liquid rocket engines are optimized for performance through the use of high area ratio nozzles to fully expand combustion gases to low exit pressures, increasing exhaust velocities. Due to the large size of such nozzles, and the related engine performance requirements, carbon-carbon (C-C) composite nozzle extensions are being considered to reduce weight impacts. Currently, the state-of-the-art is represented by the metallic and foreign composite nozzle extensions limited to approximately 2000 degrees F. used on the Atlas V, Delta IV, Falcon 9, and Ariane 5 launch vehicles. NASA and industry partners are working towards advancing the domestic supply chain for C-C composite nozzle extensions. These development efforts are primarily being conducted through the NASA Small Business Innovation Research (SBIR) program in addition to other low level internal research efforts. This has allowed for the initial material development and characterization, subscale hardware fabrication, and completion of hot-fire testing in relevant environments. NASA and industry partners have designed, fabricated and hot-fire tested several subscale domestically produced C-C extensions to advance the material and coatings fabrication technology for use with a variety of liquid rocket and scramjet engines. Testing at NASA's Marshall Space Flight Center (MSFC) evaluated heritage and state-of-the-art C-C materials and coatings, demonstrating the initial capabilities of the high temperature materials and their fabrication methods. This paper discusses the initial material development, design and fabrication of the subscale carbon-carbon nozzle extensions, provides an overview of the test campaign, presents results of the hot fire testing, and discusses potential follow-on development work. The follow on work includes the fabrication of ultra-high temperature materials, larger C-C nozzle extensions, material characterization, sub-element testing and hot-fire testing at

  20. PDE Nozzle Optimization Using a Genetic Algorithm

    Science.gov (United States)

    Billings, Dana; Turner, James E. (Technical Monitor)

    2000-01-01

    Genetic algorithms, which simulate evolution in natural systems, have been used to find solutions to optimization problems that seem intractable to standard approaches. In this study, the feasibility of using a GA to find an optimum, fixed profile nozzle for a pulse detonation engine (PDE) is demonstrated. The objective was to maximize impulse during the detonation wave passage and blow-down phases of operation. Impulse of each profile variant was obtained by using the CFD code Mozart/2.0 to simulate the transient flow. After 7 generations, the method has identified a nozzle profile that certainly is a candidate for optimum solution. The constraints on the generality of this possible solution remain to be clarified.

  1. Calibration of Axisymmetric and Quasi-1D Solvers for High Enthalpy Nozzles

    Science.gov (United States)

    Papadopoulos, P. E.; Gochberg, L. A.; Tokarcik-Polsky, S.; Venkatapathy, E.; Deiwert, G. S.; Edwards, Thomas A. (Technical Monitor)

    1994-01-01

    The proposed paper will present a numerical investigation of the flow characteristics and boundary layer development in the nozzles of high enthalpy shock tunnel facilities used for hypersonic propulsion testing. The computed flow will be validated against existing experimental data. Pitot pressure data obtained at the entrance of the test cabin will be used to validate the numerical simulations. It is necessary to accurately model the facility nozzles in order to characterize the test article flow conditions. Initially the axisymmetric nozzle flow will be computed using a Navier Stokes solver for a range of reservoir conditions. The calculated solutions will be compared and calibrated against available experimental data from the DLR HEG piston-driven shock tunnel and the 16-inch shock tunnel at NASA Ames Research Center. The Reynolds number is assumed to be high enough at the throat that the boundary layer flow is assumed turbulent at this point downstream. The real gas affects will be examined. In high Mach number facilities the boundary layer is thick. Attempts will be made to correlate the boundary layer displacement thickness. The displacement thickness correlation will be used to calibrate the quasi-1D codes NENZF and LSENS in order to provide fast and efficient tools of characterizing the facility nozzles. The calibrated quasi-1D codes will be implemented to study the effects of chemistry and the flow condition variations at the test section due to small variations in the driver gas conditions.

  2. General aspects of design and vessel nozzle analysis of nuclear power plants

    International Nuclear Information System (INIS)

    Back, N.

    1980-01-01

    Aspects of design and a procedure for nozzle tensile analysis under loads in project, normal and abnormal, emergency, failure and test conditions. For each condition, considerations about the tensile calculation methods, the tensile classification in corresponding categories and the comparison with admissible limits according to the norms. (M.C.K.) [pt

  3. Thiokol 260-SL Nozzle Development Program

    Science.gov (United States)

    1967-01-01

    excited by the above environments were investigated. These were: (a) lateral vibration of the nozzle exit cone as a cantilever beam , (b) radial vibration...under the debulking roller to prevent springback of the material. The cooling of the wrapped tape tended to set the material and prevent subsequent...between sheets of nylon were then placed at intervals on the surface of the shell as shown in Figure 10. The convergent ablative stack was then

  4. Nonequilibrium in a low power arcjet nozzle

    Science.gov (United States)

    Zube, Dieter M.; Myers, Roger M.

    1991-01-01

    Emission spectroscopy measurements were made of the plasma flow inside the nozzle of a 1 kW class arcjet thruster. The thruster propellant was a hydrogen-nitrogen mixture used to simulate fully decomposed hydrazine. The 0.25 mm diameter holes were drilled into the diverging section of the tungsten thruster nozzle to provide optical access to the internal flow. Atomic electron excitation, vibrational, and rotational temperatures were determined for the expanding plasma using relative line intensity techniques. The atomic excitation temperatures decreased from 18,000K at a location 3 mm downstream of the constrictor to 9,000K at a location 9 mm from the constrictor, while the molecular vibrational and rotational temperatures decreased from 6,500K to 2,500K and from 8,000K to 3,000K, respectively, between the same locations. The electron density measured using hydrogen H line Stark broadening decreased from about 10(exp 15) cm(-3) to about 2 times 10(exp 14) cm(-3) during the expansion. The results show that the plasma is highly nonequilibrium throughout the nozzle, with most relaxation times equal or exceeding the particle residence time.

  5. Coherent structures in a supersonic complex nozzle

    Science.gov (United States)

    Magstadt, Andrew; Berry, Matthew; Glauser, Mark

    2016-11-01

    The jet flow from a complex supersonic nozzle is studied through experimental measurements. The nozzle's geometry is motivated by future engine designs for high-performance civilian and military aircraft. This rectangular jet has a single plane of symmetry, an additional shear layer (referred to as a wall jet), and an aft deck representative of airframe integration. The core flow operates at a Mach number of Mj , c = 1 . 6 , and the wall jet is choked (Mj , w = 1 . 0). This high Reynolds number jet flow is comprised of intense turbulence levels, an intricate shock structure, shear and boundary layers, and powerful corner vortices. In the present study, stereo PIV measurements are simultaneously sampled with high-speed pressure measurements, which are embedded in the aft deck, and far-field acoustics in the anechoic chamber at Syracuse University. Time-resolved schlieren measurements have indicated the existence of strong flow events at high frequencies, at a Strouhal number of St = 3 . 4 . These appear to result from von Kàrmàn vortex shedding within the nozzle and pervade the entire flow and acoustic domain. Proper orthogonal decomposition is applied on the current data to identify coherent structures in the jet and study the influence of this vortex street. AFOSR Turbulence and Transition Program (Grant No. FA9550-15-1-0435) with program managers Dr. I. Leyva and Dr. R. Ponnappan.

  6. Improving accuracy of ET measurement of LISS nozzle to calandria tube clearance

    International Nuclear Information System (INIS)

    Craig, S.T.; Krause, T.W.; Schankula, J.J.

    2006-01-01

    The AECL Fuel Channel Inspection System (AFCIS) has been used in an in-reactor field trial to successfully measure the clearance between Liquid Injection Shutdown System (LISS) nozzles and calandria tubes. Each measurement over the full length of a channel added only 15 minutes to the on-channel inspection time. No changes were required to the inspection heads. The only equipment changes made were the addition of a Remote Field Eddy Current (RFEC) module to the eddy current instrument, and minor wiring changes, at the instrument, to achieve a RFEC configuration. With the experience gained from the field trial, factors potentially limiting accuracy were identified. These, and other factors, were investigated and are discussed herein. The RFEC probe is delivered inside the pressure tube. Magnetic fields from the RFEC probe extend through the conducting walls of the pressure tube and calandria tube to interact with the LISS nozzle. Data acquired during the field trial showed the LISS nozzle signal is distinct and the signal-to-noise ratio is very favourable. Nevertheless, comparison of the RFEC measurements to a visual examination, made during the same outage, had the RFEC method underestimating the clearance by 2.5 mm on average. By way of laboratory tests, the following factors were investigated as potential sources of error: resistivity and geometry of LISS nozzle reference/calibration pieces, pressure-tube wall thickness, diameter and resistivity variations, pressure-tube to calandria-tube gap, and radial offsets of the probe within the pressure-tube. The sensitivity to these various noise sources was established. A model, based on fundamental electromagnetic principles, was developed and was used to normalize the effects of LISS nozzle conductivity and geometry. This enabled compensation for various sources of error, and made it possible to produce a correction factor for the field trial data, reducing the average difference from the visual inspection of LISS

  7. Fully Coupled Aero-Thermochemical-Elastic Simulations of an Eroding Graphite Nozzle

    Science.gov (United States)

    Blades, E. L.; Reveles, N. D.; Nucci, M.; Maclean, M.

    2017-01-01

    A multiphysics simulation capability has been developed that incorporates mutual interactions between aerodynamics, structural response from aero/thermal loading, ablation/pyrolysis, heating, and surface-to-surface radiation to perform high-fidelity, fully coupled aerothermoelastic ablation simulations, which to date had been unattainable. The multiphysics framework couples CHAR (a 3-D implicit charring ablator solver), Loci/CHEM (a computational fluid dynamics solver for high-speed chemically reacting flows), and Abaqus (a nonlinear structural dynamics solver) to create a fully coupled aerothermoelastic charring ablative solver. The solvers are tightly coupled in a fully integrated fashion to resolve the effects of the ablation pyrolysis and charring process and chemistry products upon the flow field, the changes in surface geometry due to recession upon the flow field, and thermal-structural analysis of the body from the induced aerodynamic heating from the flow field. The multiphysics framework was successfully demonstrated on a solid rocket motor graphite nozzle erosion application. Comparisons were made with available experimental data that measured the throat erosion during the motor firing. The erosion data is well characterized, as the test rig was equipped with a windowed nozzle section for real-time X-ray radiography diagnostics of the instantaneous throat variations for deducing the instantaneous erosion rates. The nozzle initially undergoes a nozzle contraction due to thermal expansion before ablation effects are able to widen the throat. A series of parameters studies were conducted using the coupled simulation capability to determine the sensitivity of the nozzle erosion to different parameters. The parameter studies included the shape of the nozzle throat (flat versus rounded), the material properties, the effect of the choice of turbulence model, and the inclusion or exclusion of the mechanical thermal expansion. Overall, the predicted results match

  8. Transient Three-Dimensional Analysis of Side Load in Liquid Rocket Engine Nozzles

    Science.gov (United States)

    Wang, Ten-See

    2004-01-01

    Three-dimensional numerical investigations on the nozzle start-up side load physics were performed. The objective of this study is to identify the three-dimensional side load physics and to compute the associated aerodynamic side load using an anchored computational methodology. The computational methodology is based on an unstructured-grid, and pressure-based computational fluid dynamics formulation, and a simulated inlet condition based on a system calculation. Finite-rate chemistry was used throughout the study so that combustion effect is always included, and the effect of wall cooling on side load physics is studied. The side load physics captured include the afterburning wave, transition from free- shock to restricted-shock separation, and lip Lambda shock oscillation. With the adiabatic nozzle, free-shock separation reappears after the transition from free-shock separation to restricted-shock separation, and the subsequent flow pattern of the simultaneous free-shock and restricted-shock separations creates a very asymmetric Mach disk flow. With the cooled nozzle, the more symmetric restricted-shock separation persisted throughout the start-up transient after the transition, leading to an overall lower side load than that of the adiabatic nozzle. The tepee structures corresponding to the maximum side load were addressed.

  9. Effect of chevron nozzle penetration on aero-acoustic characteristics of jet at M = 0.8

    Science.gov (United States)

    Nikam, S. R.; Sharma, S. D.

    2017-12-01

    Aero-acoustic characteristics of a high-speed jet with chevron nozzles are experimentally investigated at a Mach number of 0.8. The main focus is to examine the effects of the extent of chevron penetration and its position in the mixing layer. Chevron nozzles with three different levels of penetration employed at three different longitudinal locations from the nozzle lip are tested, and the results are compared with those of a plain baseline nozzle. The chevrons are found to produce a lobed shear layer through the notched region, thereby increasing the surface area of the jet, particularly in the close vicinity of the nozzle, which increases the mixing and reduces the potential core length. This effect becomes more prominent with increasing penetration closer to the nozzle lip in the thinner mixing layer. Near field and far field noise measurements show distinctly different acoustic features due to chevrons. The chevrons are found to effectively shift the dominant noise source upstream closer to the nozzle. Present investigation proposes a simpler method for locating the dominant noise source from the peak of the centerline velocity decay rate. The overall noise levels registered along the jet edge immediately downstream of the chevrons are higher, but further downstream they are reduced in comparison with the plain baseline nozzle. Also, the chevrons beam the noise towards higher polar angles at higher frequencies. At shallow polar angles with respect to the jet axis in the far field, chevrons suppress the noise at low frequencies with increasing penetration, but for higher polar angles, while they continue to suppress the low frequency noise, at higher frequencies the trend is found to reverse. The noise measured in the near field close to the jet edge is composed of two components: acoustic and hydrodynamic. Of these two components, the chevrons are found to reduce the hydrodynamic component in comparison with the acoustic one.

  10. Development and validation of a correlation for exit velocity of water through OP nozzle using CFD simulation

    Science.gov (United States)

    Singh, Jeetendra Kumar; Peterson, Chris

    2012-06-01

    Calculation of water exit velocity from the nozzle is critical for predicting accurate water droplet size and droplet penetration length. Laboratory test was conducted to collect pressure drop versus water flow rate information. Stroke length and exit velocity of water were not measured directly in the lab test. Computational Fluid Dynamics (CFD) simulation in conjunction with Lab test data are used for developing a mathematical correlation for calculating clearance in nozzle and water exit velocity. Validation of developed correlation is done with test and CFD results and it matches very well.

  11. Pressurizer with a mechanically attached surge nozzle thermal sleeve

    Energy Technology Data Exchange (ETDEWEB)

    Wepfer, Robert M

    2014-03-25

    A thermal sleeve is mechanically attached to the bore of a surge nozzle of a pressurizer for the primary circuit of a pressurized water reactor steam generating system. The thermal sleeve is attached with a series of keys and slots which maintain the thermal sleeve centered in the nozzle while permitting thermal growth and restricting flow between the sleeve and the interior wall of the nozzle.

  12. Fluidized-bed calciner with combustion nozzle and shroud

    International Nuclear Information System (INIS)

    Wielang, J.A.; Palmer, W.B.; Kerr, W.B.

    1977-01-01

    A nozzle employed as a burner within a fluidized bed is coaxially enclosed within a tubular shroud that extends beyond the nozzle length into the fluidized bed. The open-ended shroud portion beyond the nozzle end provides an antechamber for mixture and combustion of atomized fuel with an oxygen-containing gas. The arrangement provides improved combustion efficiency and excludes bed particles from the high-velocity, high-temperature portions of the flame to reduce particle attrition. 4 claims, 2 figures

  13. Human vigilance investigation analysis of the pattern array test (further data analysis). Final report

    International Nuclear Information System (INIS)

    Have, A.C.

    1979-04-01

    This report analyzes a test which was designed to help solve problems of human vigilance encountered in a material safeguard system. The test was designed to determine the efficiency of an operator when processing large amounts of information from a video screen over extended periods of time. In the test eight objects, either circles, squares, or triangles, were set in a 5 x 5 matrix which appeared on a video screen. The eight objects were shown for a specified length of time, the screen blanked out for another specified period, then eight objects in the same 5 x 5 matrix were again shown. The observer was tested on his ability to discern changes in patterns and/or symbols from frame to frame. The testees were able to identify changes in pattern easier than changes in symbols

  14. Preliminary Two-Phase Terry Turbine Nozzle Models for RCIC Off-Design Operation Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Haihua [Idaho National Lab. (INL), Idaho Falls, ID (United States); O' Brien, James [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2017-06-12

    This report presents the effort to extend the single-phase analytical Terry turbine model to cover two-phase off-design conditions. The work includes: (1) adding well-established two-phase choking models – the Isentropic Homogenous Equilibrium Model (IHEM) and Moody’s model, and (2) theoretical development and implementation of a two-phase nozzle expansion model. The two choking models provide bounding cases for the two-phase choking mass flow rate. The new two-phase Terry turbine model uses the choking models to calculate the mass flow rate, the critical pressure at the nozzle throat, and steam quality. In the divergent stage, we only consider the vapor phase with a similar model for the single-phase case by assuming that the liquid phase would slip along the wall with a much slower speed and will not contribute the impulse on the rotor. We also modify the stagnation conditions according to two-phase choking conditions at the throat and the cross-section areas for steam flow at the nozzle throat and at the nozzle exit. The new two-phase Terry turbine model was benchmarked with the same steam nozzle test as for the single-phase model. Better agreement with the experimental data is observed than from the single-phase model. We also repeated the Terry turbine nozzle benchmark work against the Sandia CFD simulation results with the two-phase model for the pure steam inlet nozzle case. The RCIC start-up tests were simulated and compared with the single-phase model. Similar results are obtained. Finally, we designed a new RCIC system test case to simulate the self-regulated Terry turbine behavior observed in Fukushima accidents. In this test, a period inlet condition for the steam quality varying from 1 to 0 is applied. For the high quality inlet period, the RCIC system behaves just like the normal operation condition with a high pump injection flow rate and a nominal steam release rate through the turbine, with the net addition of water to the primary system; for

  15. Erosion resistant nozzles for laser plasma extreme ultraviolet (EUV) sources

    Science.gov (United States)

    Kubiak, Glenn D.; Bernardez, II, Luis J.

    2000-01-04

    A gas nozzle having an increased resistance to erosion from energetic plasma particles generated by laser plasma sources. By reducing the area of the plasma-facing portion of the nozzle below a critical dimension and fabricating the nozzle from a material that has a high EUV transmission as well as a low sputtering coefficient such as Be, C, or Si, it has been shown that a significant reduction in reflectance loss of nearby optical components can be achieved even after exposing the nozzle to at least 10.sup.7 Xe plasma pulses.

  16. Low Cost Carbon-Carbon Rocket Nozzle Development, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This development will provide an inexpensive vacuum nozzle manufacturing option for NOFBXTM monopropellant systems that are currently being developed under NASA SBIR...

  17. Optimization of Profile and Material of Abrasive Water Jet Nozzle

    Science.gov (United States)

    Anand Bala Selwin, K. P.; Ramachandran, S.

    2017-05-01

    The objective of this work is to study the behaviour of the abrasive water jet nozzle with different profiles and materials. Taguchi-Grey relational analysis optimization technique is used to optimize the value with different material and different profiles. Initially the 3D models of the nozzle are modelled with different profiles by changing the tapered inlet angle of the nozzle. The different profile models are analysed with different materials and the results are optimized. The optimized results would give the better result taking wear and machining behaviour of the nozzle.

  18. Heat and fluid flow properties of circular impinging jet with a low nozzle to plate spacing. Improvement by nothched nozzle; Nozzle heibankan kyori ga chiisai baai no enkei shototsu funryu no ryudo dennetsu tokusei. Kirikaki nozzle ni yoru kaizen kojo

    Energy Technology Data Exchange (ETDEWEB)

    Shakouchih, T. [Mie University, Mie (Japan). Faculty of Engineering; Matsumoto, A.; Watanabe, A.

    2000-10-25

    It is well known that as decreasing the nozzle to plate spacing considerably the heat transfer coefficient of circular impinging jet, which impinges to the plate normally, increases remarkably. At that time, the flow resistance of nozzle-plate system also increases rapidly. In this study, in order to reduce the flow resistance and to enhance the heat transfer coefficient of the circular impinging jet with a considerably low nozzle to plate spacing, a special nozzle with notches is proposed, and considerable improvement of the flow and heat transfer properties are shown. The mechanism of enhancement of the heat transfer properties is also discussed. (author)

  19. Variable volume combustor with aerodynamic fuel flanges for nozzle mounting

    Science.gov (United States)

    McConnaughhay, Johnie Franklin; Keener, Christopher Paul; Johnson, Thomas Edward; Ostebee, Heath Michael

    2016-09-20

    The present application provides a combustor for use with a gas turbine engine. The combustor may include a number of micro-mixer fuel nozzles and a fuel injection system for providing a flow of fuel to the micro-mixer fuel nozzles. The fuel injection system may include a number of support struts supporting the fuel nozzles and for providing the flow of fuel therethrough. The fuel injection system also may include a number of aerodynamic fuel flanges connecting the micro-mixer fuel nozzles and the support struts.

  20. Simulation and Optimization of Diffuser/Nozzle Micropump

    Directory of Open Access Journals (Sweden)

    Chandika S.

    2011-12-01

    Full Text Available Design and analysis of diffuser/nozzle micropump using ANSYS-FLUENT is attempted for fuel delivery in automobile. To enhance the performance of the micropump a historic dimensional design such as the diffuser length, the diffuser angle, and the throat/neck width of diffuser/nozzle elements are obtained from the simulation results. The fluid velocity of the diffuer/nozzle and the pressure loss rates are calculated. The simulation result shows that there is an optimal dimension of the diffuser/nozzle to obtain a large flow rate and to minimize the velocity and the pressure losses.

  1. Testing key predictions of the associative account of mirror neurons in humans using multivariate pattern analysis.

    Science.gov (United States)

    Oosterhof, Nikolaas N; Wiggett, Alison J; Cross, Emily S

    2014-04-01

    Cook et al. overstate the evidence supporting their associative account of mirror neurons in humans: most studies do not address a key property, action-specificity that generalizes across the visual and motor domains. Multivariate pattern analysis (MVPA) of neuroimaging data can address this concern, and we illustrate how MVPA can be used to test key predictions of their account.

  2. Effect of precipitation pattern on leaching of preservative from treated wood and implications for accelerated testing

    Science.gov (United States)

    Stan Lebow

    2014-01-01

    There is a need to develop improved accelerated test methods for evaluating the leaching of wood preservatives from treated wood exposed to precipitation. In this study the effects of rate of rainfall and length of intervals between rainfall events on leaching was evaluated by exposing specimens to varying patterns of simulated rainfall under controlled laboratory...

  3. Automatic Test Pattern Generator for Fuzzing Based on Finite State Machine

    Directory of Open Access Journals (Sweden)

    Ming-Hung Wang

    2017-01-01

    Full Text Available With the rapid development of the Internet, several emerging technologies are adopted to construct fancy, interactive, and user-friendly websites. Among these technologies, HTML5 is a popular one and is widely used in establishing modern sites. However, the security issues in the new web technologies are also raised and are worthy of investigation. For vulnerability investigation, many previous studies used fuzzing and focused on generation-based approaches to produce test cases for fuzzing; however, these methods require a significant amount of knowledge and mental efforts to develop test patterns for generating test cases. To decrease the entry barrier of conducting fuzzing, in this study, we propose a test pattern generation algorithm based on the concept of finite state machines. We apply graph analysis techniques to extract paths from finite state machines and use these paths to construct test patterns automatically. According to the proposal, fuzzing can be completed through inputting a regular expression corresponding to the test target. To evaluate the performance of our proposal, we conduct an experiment in identifying vulnerabilities of the input attributes in HTML5. According to the results, our approach is not only efficient but also effective for identifying weak validators in HTML5.

  4. Bottom nozzle of a LWR fuel assembly

    International Nuclear Information System (INIS)

    Leroux, J.C.

    1991-01-01

    The bottom nozzle consists of a transverse element in form of box having a bending resistant grid structure which has an outer peripheral frame of cross-section corresponding to that of the fuel assembly and which has walls defining large cells. The transverse element has a retainer plate with a regular array of openings. The retainer plate is fixed above and parallel to the grid structure with a spacing in order to form, between the grid structure and the retainer plate a free space for tranquil flow of cooling water and for debris collection [fr

  5. One- and Two-Phase Nozzle Flows.

    Science.gov (United States)

    1980-01-31

    PROJECT. TASK The Aerospace Corporation El Segundo, Calif. 90245 11. CONTROLLING OFFICE NAME AND ADDRESS Space Division31jnv 087 Air Force Systems Command...and identify by block .eintber) Gas-particle Two- phase Nozzle Transonic Flow Corn utational Method 20. AS Tf ACT (Continue an reverse side it...Dec. 1978. -51- 74.22 in. Fig.~~~~~~~ U 28.L USmalMOTOR Itro ofgrto n AEXI Fig. 2. BFC Gridl foor Smaio CUonfM igrtho n Somutaterged Noeglock x -344in

  6. The influence of nozzle type, operating pressure, and tank-mixture components on droplet characteristics and the EPA's drift reduction rating

    Science.gov (United States)

    The introduction of drift reduction technology (DRT) guidelines by the U. S. Environmental Protection Agency (EPA) has established testing protocols for nozzles, agrochemicals, application parameters, and combinations thereof for applying agrochemicals by certified individuals in the United States....

  7. Demonstration of full-field patterning of 32 nm test chips using EUVL

    Science.gov (United States)

    Vandentop, Gilroy; Chandhok, Manish; Putna, Ernisse S.; Younkin, Todd R.; Clarke, James S.; Carson, Steven; Myers, Alan; Leeson, Michael; Zhang, Guojing; Liang, Ted; Murachi, Tetsunori

    2009-03-01

    EUV lithography is considered one of the options for high volume manufacturing (HVM) of 16 nm MPU node devices [1]. The benefits of high k1(~0.5) imaging enable EUVL to simplify the patterning process and ease design rule restrictions. However, EUVL with its unique imaging process - reflective optics and masks, vacuum operation, and lack of pellicle, has several challenges to overcome before being qualified for production. Thus, it is important to demonstrate the capability to integrate EUVL into existing process flows and characterize issues which could hamper yield. A patterning demonstration of Intel's 32 nm test chips using the ADT at IMEC [7] is presented, This test chip was manufactured using processes initially developed with the Intel MET [2-4] as well as masks made by Intel's mask shop [5,6]. The 32 nm node test chips which had a pitch of 112.5 nm at the trench layer, were patterned on the ADT which resulted in a large k1 factor of 1 and consequently, the trench process window was iso-focal with MEEF = 1. It was found that all mask defects detected by a mask pattern inspection tool printed on the wafer and that 90% of these originated from the substrate. We concluded that improvements are needed in mask defects, photospeed of the resist, overlay, and tool throughput of the tool to get better results to enable us to ultimately examine yield.

  8. Computerized In Vitro Test for Chemical Toxicity Based on Tetrahymena Swimming Patterns

    Science.gov (United States)

    Noever, David A.; Matsos, Helen C.; Cronise, Raymond J.; Looger, Loren L.; Relwani, Rachna A.; Johnson, Jacqueline U.

    1994-01-01

    An apparatus and a method for rapidly determining chemical toxicity have been evaluated as an alternative to the rabbit eye initancy test (Draize). The toxicity monitor includes an automated scoring of how motile biological cells (Tetrahymena pyriformis) slow down or otherwise change their swimming patterns in a hostile chemical environment. The method, called the motility assay (MA), is tested for 30 s to determine the chemical toxicity in 20 aqueous samples containing trace organics and salts. With equal or better detection limits, results compare favorably to in vivo animal tests of eye irritancy.

  9. Chronic malaria revealed by a new fluorescence pattern on the antinuclear autoantibodies test.

    Directory of Open Access Journals (Sweden)

    Benjamin Hommel

    Full Text Available BACKGROUND: Several clinical forms of malaria such as chronic carriage, gestational malaria or hyper-reactive malarial splenomegaly may follow a cryptic evolution with afebrile chronic fatigue sometimes accompanied by anemia and/or splenomegaly. Conventional parasitological tests are often negative or not performed, and severe complications may occur. Extensive explorations of these conditions often include the search for antinuclear autoantibodies (ANA. METHODS: We analysed fluorescence patterns in the ANA test in patients with either chronic cryptic or acute symptomatic malaria, then conducted a one-year prospective study at a single hospital on all available sera drawn for ANA detections. We then identified autoantibodies differentially expressed in malaria patients and in controls using human protein microarray. RESULTS: We uncovered and defined a new, malaria-related, nucleo-cytoplasmic ANA pattern displaying the specific association of a nuclear speckled pattern with diffuse cytoplasmic perinuclearly-enhanced fluorescence. In the one-year prospective analysis, 79% of sera displaying this new nucleo-cytoplasmic fluorescence were from patients with malaria. This specific pattern, not seen in other parasitic diseases, allowed a timely reorientation of the diagnosis toward malaria. To assess if the autoantibody immune response was due to autoreactivity or molecular mimicry we isolated 42 autoantigens, targets of malarial autoantibodies. BLAST analysis indicated that 23 of recognized autoantigens were homologous to plasmodial proteins suggesting autoimmune responses directly driven by the plasmodial infection. CONCLUSION: In patients with malaria in whom parasitological tests have not been performed recognition of this new, malaria-related fluorescence pattern on the ANA test is highly suggestive of the diagnosis and triggers immediate, easy confirmation and adapted therapy.

  10. Thermo-Structural Response Caused by Structure Gap and Gap Design for Solid Rocket Motor Nozzles

    Directory of Open Access Journals (Sweden)

    Lin Sun

    2016-06-01

    Full Text Available The thermo-structural response of solid rocket motor nozzles is widely investigated in the design of modern rockets, and many factors related to the material properties have been considered. However, little work has been done to evaluate the effects of structure gaps on the generation of flame leaks. In this paper, a numerical simulation was performed by the finite element method to study the thermo-structural response of a typical nozzle with consideration of the structure gap. Initial boundary conditions for thermo-structural simulation were defined by a quasi-1D model, and then coupled simulations of different gap size matching modes were conducted. It was found that frictional interface treatment could efficiently reduce the stress level. Based on the defined flame leak criteria, gap size optimization was carried out, and the best gap matching mode was determined for designing the nozzle. Testing experiment indicated that the simulation results from the proposed method agreed well with the experimental results. It is believed that the simulation method is effective for investigating thermo-structural responses, as well as designing proper gaps for solid rocket motor nozzles.

  11. Designs of contraction nozzle and concave back-wall for IFMIF target

    International Nuclear Information System (INIS)

    Ida, Mizuho; Nakamura, Hideo; Nakamura, Hiroo; Takeuchi, Hiroshi

    2004-01-01

    For the liquid lithium flow target of International Fusion Materials Irradiation Facility (IFMIF), the double reducer (two-step contraction) nozzle with a high-contraction ratio of 10 which generated high-speed uniform jet flows up to 20 m/s was proposed. Multi-dimensional hydraulic analyses were carried out to verify the performance of the proposed nozzle. The analytical results showed that the double reducer nozzle would well generate high-speed uniform flow, while one-step contraction nozzle generated non-uniform flow and resulted in flow thickening at the beam footprint. For the target design, the range of the concave back-wall radius with no lithium boiling due to the centrifugal force and proper component arrangement in the irradiation test cell was determined by the thermal-hydraulic analysis of a free-surface flow. It was verified that the back-wall radius from 0.25 to 10 m was acceptable in the velocity range of 10-20 m/s

  12. Influence of Fluid–Thermal–Structural Interaction on Boundary Layer Flow in Rectangular Supersonic Nozzles

    Directory of Open Access Journals (Sweden)

    Kalyani Bhide

    2018-03-01

    Full Text Available The aim of this work is to highlight the significance of Fluid–Thermal–Structural Interaction (FTSI as a diagnosis of existing designs, and as a means of preliminary investigation to ensure the feasibility of new designs before conducting experimental and field tests. The novelty of this work lies in the multi-physics simulations, which are, for the first time, performed on rectangular nozzles. An existing experimental supersonic rectangular converging/diverging nozzle geometry is considered for multi-physics 3D simulations. A design that has been improved by eliminating the sharp throat is further investigated to evaluate its structural integrity at design Nozzle Pressure Ratio (NPR 3.67 and off-design (NPR 4.5 conditions. Static structural analysis is performed by unidirectional coupling of pressure loads from steady 3D Computational Fluid Dynamics (CFD and thermal loads from steady thermal conduction simulations, such that the simulations represent the experimental set up. Structural deformation in the existing design is far less than the boundary layer thickness, because the impact of Shock wave Boundary Layer Interaction (SBLI is not as severe. FTSI demonstrates that the discharge coefficient of the improved design is 0.99, and its structural integrity remains intact at off-design conditions. This proves the feasibility of the improved design. Although FTSI influence is shown for a nozzle, the approach can be applied to any product design cycle, or as a prelude to building prototypes.

  13. Combining spray nozzle simulators with meshes: characterization of rainfall intensity and drop properties

    Science.gov (United States)

    Carvalho, Sílvia C. P.; de Lima, João L. M. P.; de Lima, M. Isabel P.

    2013-04-01

    Rainfall simulators can be a powerful tool to increase our understanding of hydrological and geomorphological processes. Nevertheless, rainfall simulators' design and operation might be rather demanding, for achieving specific rainfall intensity distributions and drop characteristics. The pressurized simulators have some advantages over the non-pressurized simulators: drops do not rely on gravity to reach terminal velocity, but are sprayed out under pressure; pressurized simulators also yield a broad range of drop sizes in comparison with drop-formers simulators. The main purpose of this study was to explore in the laboratory the potential of combining spray nozzle simulators with meshes in order to change rainfall characteristics (rainfall intensity and diameters and fall speed of drops). Different types of spray nozzles were tested, such as single full-cone and multiple full-cone nozzles. The impact of the meshes on the simulated rain was studied by testing different materials (i.e. plastic and steel meshes), square apertures and wire thicknesses, and different vertical distances between the nozzle and the meshes underneath. The diameter and fall speed of the rain drops were measured using a Laser Precipitation Monitor (Thies Clima). The rainfall intensity range and coefficients of uniformity of the sprays and the drop size distribution, fall speed and kinetic energy were analysed. Results show that when meshes intercept drop trajectories the spatial distribution of rainfall intensity and the drop size distribution are affected. As the spray nozzles generate typically small drop sizes and narrow drop size distributions, meshes can be used to promote the formation of bigger drops and random their landing positions.

  14. Transient Three-Dimensional Side Load Analysis of Out-of-Round Film Cooled Nozzles

    Science.gov (United States)

    Wang, Ten-See; Lin, Jeff; Ruf, Joe; Guidos, Mike

    2010-01-01

    The objective of this study is to investigate the effect of nozzle out-of-roundness on the transient startup side loads at a high altitude, with an anchored computational methodology. The out-of-roundness could be the result of asymmetric loads induced by hardware attached to the nozzle, asymmetric internal stresses induced by previous tests, and deformation, such as creep, from previous tests. The rocket engine studied encompasses a regeneratively cooled thrust chamber and a film cooled nozzle extension with film coolant distributed from a turbine exhaust manifold. The computational methodology is based on an unstructured-grid, pressure-based computational fluid dynamics formulation, and a transient inlet history based on an engine system simulation. Transient startup computations were performed with the out-of-roundness achieved by four different degrees of ovalization: one perfectly round, one slightly out-of-round, one more out-of-round, and one significantly out-of-round. The results show that the separation-line-jump is the peak side load physics for the round, slightly our-of-round, and more out-of-round cases, and the peak side load increases as the degree of out-of-roundness increases. For the significantly out-of-round nozzle, however, the peak side load reduces to comparable to that of the round nozzle and the separation line jump is not the peak side load physics. The counter-intuitive result of the significantly out-of-round case is found to be related to a side force reduction mechanism that splits the effect of the separation-line-jump into two parts, not only in the circumferential direction and most importantly in time.

  15. Analysis of film cooling in rocket nozzles

    Science.gov (United States)

    Woodbury, Keith A.

    1993-01-01

    This report summarizes the findings on the NASA contract NAG8-212, Task No. 3. The overall project consists of three tasks, all of which have been successfully completed. In addition, some supporting supplemental work, not required by the contract, has been performed and is documented herein. Task 1 involved the modification of the wall functions in the code FDNS (Finite Difference Navier-Stokes) to use a Reynolds Analogy-based method. This task was completed in August, 1992. Task 2 involved the verification of the code against experimentally available data. The data chosen for comparison was from an experiment involving the injection of helium from a wall jet. Results obtained in completing this task also show the sensitivity of the FDNS code to unknown conditions at the injection slot. This task was completed in September, 1992. Task 3 required the computation of the flow of hot exhaust gases through the P&W 40K subscale nozzle. Computations were performed both with and without film coolant injection. This task was completed in July, 1993. The FDNS program tends to overpredict heat fluxes, but, with suitable modeling of backside cooling, may give reasonable wall temperature predictions. For film cooling in the P&W 40K calorimeter subscale nozzle, the average wall temperature is reduced from 1750R to about 1050R by the film cooling. The average wall heat flux is reduced by a factor of 3.

  16. Multiple hypotheses testing of fish incidence patterns in an urbanized ecosystem

    Science.gov (United States)

    Chizinski, C.J.; Higgins, C.L.; Shavlik, C.E.; Pope, K.L.

    2006-01-01

    Ecological and evolutionary theories have focused traditionally on natural processes with little attempt to incorporate anthropogenic influences despite the fact that humans are such an integral part of virtually all ecosystems. A series of alternate models that incorporated anthropogenic factors and traditional ecological mechanisms of invasion to account for fish incidence patterns in urban lakes was tested. The models were based on fish biology, human intervention, and habitat characteristics. However, the only models to account for empirical patterns were those that included fish invasiveness, which incorporated species-specific information about overall tolerance and fecundity. This suggests that species-specific characteristics are more important in general distributional patterns than human-mediated dispersal. Better information of illegal stocking activities is needed to improve human-mediated models, and more insight into basic life history of ubiquitous species is needed to truly understand underlying mechanisms of biotic homogenization. ?? Springer 2005.

  17. Finite element analysis of inclined nozzle-plate junctions

    International Nuclear Information System (INIS)

    Dixit, K.B.; Seth, V.K.; Krishnan, A.; Ramamurthy, T.S.; Dattaguru, B.; Rao, A.K.

    1979-01-01

    Estimation of stress concentration at nozzle to plate or shell junctions is a significant problem in the stress analysis of nuclear reactors. The topic is a subject matter of extensive investigations and earlier considerable success has been reported on analysis for the cases when the nozzle is perpendicular to the plate or is radial to the shell. Analytical methods for the estimation of stress concentrations for the practical situations when the intersecting nozzle is inclined to the plate or is non-radial to the shell is rather scanty. Specific complications arise in dealing with the junction region when the nozzle with circular cross-section meets the non-circular cut-out on the plate or shell. In this paper a finite element analysis is developed for inclined nozzles and results are presented for nozzle-plate junctions. A method of analysis is developed with a view to achieving simultaneously accuracy of results and simplicity in the choice of elements and their connectivity. The circular nozzle is treated by axisymmetric conical shell elements. The nozzle portion in the region around the junction and the flat plate is dealt with by triangular flat shell elements. Special transition elements are developed for joining the flat shell elements with the axisymmetric elements under non-axisymmetric loading. A substructure method of analysis is adopted which achieves considerable economy in handling the structure and also conveniently combines the different types of elements in the structure. (orig.)

  18. Combustor nozzle for a fuel-flexible combustion system

    Science.gov (United States)

    Haynes, Joel Meier [Niskayuna, NY; Mosbacher, David Matthew [Cohoes, NY; Janssen, Jonathan Sebastian [Troy, NY; Iyer, Venkatraman Ananthakrishnan [Mason, OH

    2011-03-22

    A combustor nozzle is provided. The combustor nozzle includes a first fuel system configured to introduce a syngas fuel into a combustion chamber to enable lean premixed combustion within the combustion chamber and a second fuel system configured to introduce the syngas fuel, or a hydrocarbon fuel, or diluents, or combinations thereof into the combustion chamber to enable diffusion combustion within the combustion chamber.

  19. Analytical study of nozzle performance for nuclear thermal rockets

    International Nuclear Information System (INIS)

    Davidian, K.O.; Kacynski, K.J.

    1991-01-01

    Nuclear propulsion has been identified as one of the key technologies needed for human exploration of the Moon and Mars. The Nuclear Thermal Rocket (NTR) uses a nuclear reactor to heat hydrogen to a high temperature followed by expansion through a conventional convergent-divergent nozzle. A parametric study of NTR nozzles was performed using the Rocket Engine Design Expert System (REDES) at the NASA Lewis Research Center. The REDES used the JANNAF standard rigorous methodology to determine nozzle performance over a range of chamber temperatures, chamber pressures, thrust levels, and different nozzle configurations. A design condition was set by fixing the propulsion system exit radius at five meters and throat radius was varied to achieve a target thrust level. An adiabatic wall was assumed for the nozzle, and its length was assumed to be 80 percent of a 15 degree cone. The results conclude that although the performance of the NTR, based on infinite reaction rates, looks promising at low chamber pressures, finite rate chemical reactions will cause the actual performance to be considerably lower. Parameters which have a major influence on the delivered specific impulse value include the chamber temperature and the chamber pressures in the high thrust domain. Other parameters, such as 2-D and boundary layer effects, kinetic rates, and number of nozzles, affect the deliverable performance of an NTR nozzle to a lesser degree. For a single nozzle, maximum performance of 930 seconds and 1030 seconds occur at chamber temperatures of 2700 and 3100 K, respectively

  20. Numerical analysis of choked converging nozzle flows with surface ...

    Indian Academy of Sciences (India)

    Choked converging nozzle flow and heat transfer characteristics are numerically investigated by means of a recent computational model that integrates the axisymmetric continuity, state, momentum and energy equations. To predict the combined effects of nozzle geometry, friction and heat transfer rates, analyses are ...

  1. Design and Optimization of Aerospike nozzle using CFD

    Science.gov (United States)

    Naveen Kumar, K.; Gopalsamy, M.; Antony, Daniel; Krishnaraj, R.; Viswanadh, Chaparala B. V.

    2017-10-01

    New rocket designs are being adopted to increase the performance of the current satellite launch vehicles (SLVs). But, the aerospike (or plug) nozzle concept that has been under development since the 1950s is yet to be utilized on a launch platform. Due to its ability to adjust the environment by altering the outer jet boundary, the aerospike nozzle delivers better performance compared to present day bell nozzle. An aerospike nozzle is designed for 20 bar pressure ratio. In order to improve the performance of the aerospike nozzle for various conditions, optimization of the nozzle was carried out for some important design parameters and their performances were studied for cold flow conditions. Initially a model of an aerospike nozzle is created for certain parameters, then the optimization process is carried out for the nozzle (Truncated model & Base bleed model). Optimized model is designed by the software GAMBIT and the flow behaviour is analysed by the Computational Fluid Dynamics (CFD) software called FLUENT. Comparison also takes place between the full length and the optimized models.

  2. Numerical analysis of choked converging nozzle flows with surface ...

    Indian Academy of Sciences (India)

    Variation of discharge coefficients for sonic nozzles with flow geometry and Reynolds num- ber was reported by Paik et al (2000), who determined higher discharge coefficients with the increase of mass flow rate. Lear et al (1997) modelled dissipative effects of heat trans- fer on the exit kinetic energy and on nozzle efficiency ...

  3. Multi-orifice deposition nozzle for additive manufacturing

    Science.gov (United States)

    Lind, Randall F.; Post, Brian K.; Cini, Colin L.

    2017-11-21

    An additive manufacturing extrusion head includes a nozzle for accepting and depositing a heated material onto a work surface and/or part. The nozzle includes a valve body and an internal poppet body moveable between positions to permit deposition of at least two bead sizes of heated material onto a work surface and/or part.

  4. The Effect of Nozzle Trailing Edge Thickness on Jet Noise

    Science.gov (United States)

    Henderson, Brenda; Kinzie, Kevin; Haskin, Henry

    2004-01-01

    The effect of nozzle trailing edge thickness on broadband acoustic radiation and the production of tones is investigated for coannular nozzles. Experiments were performed for a core nozzle trailing edge thickness between 0.38 mm and 3.17 mm. The on-set of discrete tones was found to be predominantly affected by the velocity ratio, the ratio of the fan velocity to the core velocity, although some dependency on trailing edge thickness was also noted. For a core nozzle trailing edge thickness greater than or equal to 0.89 mm, tones were produced for velocity ratios between 0.91 and 1.61. For a constant nozzle trailing edge thickness, the frequency varied almost linearly with the core velocity. The Strouhal number based on the core velocity changed with nozzle trailing edge thickness and varied between 0.16 and 0.2 for the core nozzles used in the experiments. Increases in broadband noise with increasing trailing edge thickness were observed for tone producing and non-tone producing conditions. A variable thickness trailing edge (crenellated) nozzle resulted in no tonal production and a reduction of the broadband trailing edge noise relative to that of the corresponding constant thickness trailing edge.

  5. Thermographic Leak Detection of the Space Shuttle Main Engine Nozzle

    Science.gov (United States)

    Walker, James L.; Russell, Samuel S.

    1999-01-01

    The Space Shuttle Main Engines Nozzles consist of over one thousand tapered Inconel coolant tubes brazed to a stainless steel structural jacket. Liquid Hydrogen flows through the tubing, from the aft to forward end of the nozzle, under high pressure to maintain a thermal balance between the rocket exhaust and the nozzle wall. Three potential problems occur within the SSME nozzle coolant tubes as a result of manufacturing anomalies and the highly volatile service environment including poor or incomplete bonding of the tubes to the structural jacket, cold wall leaks and hot wall leaks. Of these conditions the identification of cold wall leaks has been the most problematic. The methods and results presented in this summary addresses the thermographic identification of cold wall "interstitial" leaks between the structural jacket and coolant tubes of the Space Shuttle Main Engines Nozzles.

  6. Study on steam pressure characteristics in various types of nozzles

    Science.gov (United States)

    Firman; Anshar, Muhammad

    2018-03-01

    Steam Jet Refrigeration (SJR) is one of the most widely applied technologies in the industry. The SJR system was utilizes residual steam from the steam generator and then flowed through the nozzle to a tank that was containing liquid. The nozzle converts the pressure energy into kinetic energy. Thus, it can evaporate the liquid briefly and release it to the condenser. The chilled water, was produced from the condenser, can be used to cool the product through a heat transfer process. This research aims to study the characteristics of vapor pressure in different types of nozzles using a simulation. The Simulation was performed using ANSYS FLUENT software for nozzle types such as convergent, convrgent-parallel, and convergent-divergent. The results of this study was presented the visualization of pressure in nozzles and was been validated with experiment data.

  7. Use of calophyllum inophyllum biofuel blended with diesel in DI diesel engine modified with nozzle holes and its size

    Science.gov (United States)

    Vairamuthu, G.; Sundarapandian, S.; Thangagiri, B.

    2016-05-01

    Improved thermal efficiency, reduction in fuel consumption and pollutant emissions from biodiesel fueled diesel engines are important issues in engine research. To achieve these, fast and perfect air-biodiesel mixing are the most important requirements. The mixing quality of biodiesel spray with air can be improved by better design of the injection system. The diesel engine tests were conducted on a 4-stroke tangentially vertical single cylinder (TV1) kirloskar 1500 rpm water cooled direct injection diesel engine with eddy current dynamometer. In this work, by varying different nozzles having spray holes of 3 (base, Ø = 0.280 mm), 4 (modified, Ø = 0.220 mm) and 5 (modified, Ø = 0.240 mm) holes, with standard static injection timing of 23° bTDC and nozzle opening pressure (NOP) of 250 bar maintained as constant throughout the experiment under steady state at full load condition of the engine. The effect of varying different nozzle configuration (number of holes), on the combustion, performance and exhaust emissions, using a blend of calophyllum inophyllum methyl ester by volume in diesel were evaluated. The test results showed that improvement in terms of brake thermal efficiency and specific fuel consumption for 4 holes and 5 holes nozzle operated at NOP 250 bar. Substantial improvements in the reduction of emissions levels were also observed for 5 holes nozzle operated at NOP 250 bar.

  8. High-frequency jet nozzle actuators for noise reduction

    Science.gov (United States)

    Davis, Christopher L.; Calkins, Frederick T.; Butler, George W.

    2003-08-01

    Rules governing airport noise levels are becoming more restrictive and will soon affect the operation of commercial air traffic. Sound produced by jet engine exhaust, particularly during takeoff, is a major contributor to the community noise problem. The noise spectrum is broadband in character and is produced by turbulent mixing of primary, secondary, and ambient streams of the jet engine exhaust. As a potential approach to controlling the noise levels, piezoelectric bimorph actuators have been tailored to enhance the mixing of a single jet with its quiescent environment. The actuators are located at the edge of the nozzle and protrude into the exhaust stream. Several actuator configurations were considered to target two excitation frequencies, 250 Hz and 900 Hz, closely coupled to the naturally unstable frequencies of the mixing process. The piezoelectric actuators were constructed of 10 mil thick d31 poled wafer PZT-5A material bonded to either 10 or 20 mil thick spring steel substrates. Linear analytical beam models and NASTRAN finite element models were used to predict and assess the dynamic performance of the actuators. Experimental mechanical and electrical performance measurements were used to validate the models. A 3 inch diameter nozzle was fitted with actuators and tested in the Boeing Quiet Air Facility with the jet velocity varied from 50 to 1000 ft/s. Performance was evaluated using near-field and far-field acoustic data, flow visualization, and actuator health data. The overall sound pressure level produced from the 3 inch diameter jet illustrates the effect of both static and active actuators.

  9. A study on thick plate forming for hollow-partitioned steam turbine nozzle

    Science.gov (United States)

    Kwak, Bong-Seok; Kang, Byeong-Kwon; Yoon, Mahn-Jung; Jeon, Jae-Young; Kang, Beom-Soo; Ku, Tae-Wan

    2017-10-01

    In thermal and nuclear power plants, steam turbine system to generate electric power is composed of turbine rotor assemblies for high-pressure (HP) and low-pressure (LP) turbines, its main shaft, and turbine nozzle diaphragms, and so forth. Especially, the turbine nozzle diaphragm consists of many turbine nozzles with three-dimensional asymmetric shape and complicated surface curvatures at each turbine stage. In this study, main goal is tool design and fabrication, and its application to thick plate cold forming for replacing solid-type turbine nozzle manufactured by a series of metal forging process with hollow-partitioned one obtained from cold forming. The hollow-partitioned turbine nozzle (stator) has asymmetric curvature contours, so it is hard to adopt a series of draw-bead or blank holder. Thus, the thick plate as a thick blank experiences unstable and non-uniform contact on the tool surfaces in the die cavity. To easy this unstable positioning restraint in the thick plate forming, the shoulder angles of the forming punch and the lower die are selected as the geometric process parameter to control the blank position in the die cavity. The thick plate material is 409L stainless steel (SUS409L) with initial thickness of 5.00mm, and the dimensions are a length of about 980.00mm and a width of roughly 372.60mm. Uni-axial tensile tests for the initial blank material of SUS409L are performed to verify the mechanical properties including the anisotropic characteristics, and finite element simulations are carried out using ABAQUS Explicit/Implicit. As the obtained and summarized results, the suitable shoulder angle combinations of the lower die and the punch were verified as (30°, 90°) and (45°, 90°), and then the transverse blank direction (TD) of SUS409L thick plate was investigated to be well matched.

  10. A Study on the Influence of Fuel Pipe on Fuel Injection Characteristics of Each Nozzle Hole in Diesel Injector

    Directory of Open Access Journals (Sweden)

    Luo Fuqiang

    2016-01-01

    Full Text Available The inner diameter of high pressure fuel pipe has a significant effect on the fuel injection process and the performance of a diesel engine. The spray impact force of each nozzle hole of a conventional injection system of pump-line-nozzle for diesel engine (based on the spray momentum flux and the injection pressure (on a fuel injection pump test rig were measured. With varying fuel injection quantities and pump speed, the effects of the inner diameter of the high pressure fuel pipe on fuel injection process and the fuel injection characteristics of each nozzle hole were analyzed. It was noted from experimental results that the fuel injection pressure changes with variations in the inner diameter of the high pressure fuel pipe and also the injection duration gradually increases with increase in the inner diameter. At low injection pump speed, even with the same geometric fuel deliver rate, the injection duration also increases gradually. Due to throttling effect and reduction in injection pressure, the fuel injection quantities of the injection nozzle were relatively minimal when the inner diameters of the high pressure fuel pipe were respectively small and large. The optimum injection pipe inner diameter for the right quantity for fuel injection falls between the two cases (between small and large. In addition, the injection rate of each nozzle hole increases with the decrease in angle between the needle axis and each of the nozzle hole axis. The fuel injection quantity of each nozzle hole increases while their relative difference decreases with increasing pump speed.

  11. A sequential nonparametric pattern classification algorithm based on the Wald SPRT. [Sequential Probability Ratio Test

    Science.gov (United States)

    Poage, J. L.

    1975-01-01

    A sequential nonparametric pattern classification procedure is presented. The method presented is an estimated version of the Wald sequential probability ratio test (SPRT). This method utilizes density function estimates, and the density estimate used is discussed, including a proof of convergence in probability of the estimate to the true density function. The classification procedure proposed makes use of the theory of order statistics, and estimates of the probabilities of misclassification are given. The procedure was tested on discriminating between two classes of Gaussian samples and on discriminating between two kinds of electroencephalogram (EEG) responses.

  12. Pattern recognition techniques for failure trend detection in SSME ground tests

    Science.gov (United States)

    Choudry, A.

    1987-01-01

    The Space Shuttle Main Engine (SSME) is a complex power plant. To evaluate its performance 1200 hot-wire ground tests have been conducted, varying in duration from 0 to 500 secs. During the test some 500 sensors are sampled every 20 ms. The sensors are generally bounded by red lines so that an excursion beyond could lead to premature shutdown. In 27 tests it was not possible to effect an orderly premature shutdown, resulting in major incidents with serious damage to the SSME and test stand. The application of pattern recognition are investigated to detect SSME performance trends that may lead to major incidents. Based on the sensor data a set of (n) features is defined. At any time during the test, the state of the SSME is given by a point in the n-dimensional feature space. The history of a test can now be represented as a trajectory in the n-dimensional feature space. Portions of the normal trajectories and failed test trajectories would lie in different regions of the n-dimensional feature space. The latter can now be partitioned into regions of normal and failed tests. Thus, it is possible to examine the trajectory of a test in progress and predict if it is going into the normal or failure region.

  13. [Blood Test Patterns for Blood Donors after Nucleic Acid Detection in the Blood Center].

    Science.gov (United States)

    Men, Shou-Shan; Lv, Lian-Zhi; Chen, Yuan-Feng; Han, Chun-Hua; Liu, Hong-Yu; Yan, Yan

    2017-12-01

    To investigate the blood test patterns for blood donors after nucleic acid detection in blood center. The collected blood samples after voluntary blood donors first were detected by conventional ELISA, then 31981 negative samples were detected via HBV/HCV/HIV combined nucleic acid test of 6 mixed samples(22716 cases) or single samples(9265 cases) by means of Roche cobas s201 instrument. The combined detection method as follows: the blood samples were assayed by conventional nucleic acid test of 6 mixed samples, at same time, 6 mixed samples were treated with polyethylene glycol precipitation method to concentrate the virus, then the nucleic acid test of blood samples was performed; the single detection method as follows: firstly the conventional nucleic acid test of single sample was performed, then the positive reactive samples after re-examination were 6-fold diluted to simulate the nucleic acid test of 6-mixed samples. The positive rate of positive samples detected by combined nucleic acid test, positive samples detected by nucleic acid test of mixed virus concentration and positive samples detected by single nucleic acid test was statistically analyzed. In addition, for HBV + persons the serological test yet should be performed. In 22 716 samples detected by nucleic acid test of 6 mixed samples (MP-6-NAT) , 9 cases were HBV + (0.40‰, 9/22716); at same time, the detection of same samples by nucleic acid test of mixed sample virus concentration showed 29 cases of HBV + (1.28‰, 29/22716). In 9265 samples detected by single nucleic acid test(ID-NAT) 12 cases showed HBV + (1.30‰, 12/9265), meanwhile the detection of these 12 samples with HBV + by 6-fold dilution for virus concentration found only 4 samples with HBV + . In serological qualified samples, ID-NAT unqualified rate was 1.28‰, which was higher than that of MP-6-NAT(0.4‰) (χ 2 =8.11, P0.05). In 41 samples with HBsAg - HBV DNA + detected by ELISA, 36 samples were confirmed to be occult HBV

  14. Low speed wind tunnel investigation of a four-engine upper surface blown model having swept wing and rectangular and D-shaped exhaust nozzles

    Science.gov (United States)

    Sleeman, W. C., Jr.; Hohlweg, W. C.

    1975-01-01

    A low speed investigation was conducted in the Langley V/STOL tunnel to determine the power-on static-turning and powered-lift aerodynamic performance of a four engine upper surface blown transport configuration. Initial tests with a D-shaped exhaust nozzle showed relatively poor flow-turning capability, and the D-nozzles were replaced by rectangular nozzles with a width-height ratio of 6.0. The high lift system consisted of a leading edge slat and two different trailing-edge-flap configurations. A double slotted flap with the gaps sealed was investigated and a simple radius flap was also tested. A maximum lift coefficient of approximately 9.3 was obtained for the model with the rectangular exhaust nozzles with both the double slotted flap deflected 50 deg and the radius flap deflected 90 deg.

  15. Noise Prediction Module for Offset Stream Nozzles

    Science.gov (United States)

    Henderson, Brenda S.

    2011-01-01

    A Modern Design of Experiments (MDOE) analysis of data acquired for an offset stream technology was presented. The data acquisition and concept development were funded under a Supersonics NRA NNX07AC62A awarded to Dimitri Papamoschou at University of California, Irvine. The technology involved the introduction of airfoils in the fan stream of a bypass ratio (BPR) two nozzle system operated at transonic exhaust speeds. The vanes deflected the fan stream relative to the core stream and resulted in reduced sideline noise for polar angles in the peak jet noise direction. Noise prediction models were developed for a range of vane configurations. The models interface with an existing ANOPP module and can be used or future system level studies.

  16. Characterisation of inexpensive, simply shaped nozzles

    Czech Academy of Sciences Publication Activity Database

    Tesař, Václav

    2010-01-01

    Roč. 88, č. 11A (2010), s. 1433-1444 ISSN 0263-8762 R&D Projects: GA ČR GA101/07/1499; GA AV ČR IAA200760705 Institutional research plan: CEZ:AV0Z20760514 Keywords : nozzle * characteristic * separation of flow Subject RIV: BK - Fluid Dynamics Impact factor: 1.519, year: 2010 http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B8JGF-4YPPRBF-3-2X&_cdi=43669&_user=640952&_pii=S0263876210001115&_origin=search&_coverDate=11%2F30%2F2010&_sk=999119988&view=c&wchp=dGLbVlW-zSkWb&md5=dbed1a6fea7702efd86e09264ff1a0e4&ie=/sdarticle.pdf

  17. Two-phase flow patterns recognition and parameters estimation through natural circulation test loop image analysis

    International Nuclear Information System (INIS)

    Mesquita, R.N.; Libardi, R.M.P.; Masotti, P.H.F.; Sabundjian, G.; Andrade, D.A.; Umbehaun, P.E.; Torres, W.M.; Conti, T.N.; Macedo, L.A.

    2009-01-01

    Visualization of natural circulation test loop cycles is used to study two-phase flow patterns associated with phase transients and static instabilities of flow. Experimental studies on natural circulation flow were originally related to accidents and transient simulations relative to nuclear reactor systems with light water refrigeration. In this regime, fluid circulation is mainly caused by a driving force ('thermal head') which arises from density differences due to temperature gradient. Natural circulation phenomenon has been important to provide residual heat removal in cases of 'loss of pump power' or plant shutdown in nuclear power plant accidents. The new generation of compact nuclear reactors includes natural circulation of their refrigerant fluid as a security mechanism in their projects. Two-phase flow patterns have been studied for many decades, and the related instabilities have been object of special attention recently. Experimental facility is an all glass-made cylindrical tubes loop which contains about twelve demineralized water liters, a heat source by an electrical resistor immersion heater controlled by a Variac, and a helicoidal heat exchanger working as cold source. Data is obtained through thermo-pairs distributed over the loop and CCD cameras. Artificial intelligence based algorithms are used to improve (bubble) border detection and patterns recognition, in order to estimate and characterize, phase transitions patterns and correlate them with the periodic static instability (chugging) cycle observed in this circuit. Most of initial results show good agreement with previous numerical studies in this same facility. (author)

  18. Differences in walking pattern during 6-min walk test between patients with COPD and healthy subjects.

    Science.gov (United States)

    Annegarn, Janneke; Spruit, Martijn A; Savelberg, Hans H C M; Willems, Paul J B; van de Bool, Coby; Schols, Annemie M W J; Wouters, Emiel F M; Meijer, Kenneth

    2012-01-01

    To date, detailed analyses of walking patterns using accelerometers during the 6-min walk test (6MWT) have not been performed in patients with chronic obstructive pulmonary disease (COPD). Therefore, it remains unclear whether and to what extent COPD patients have an altered walking pattern during the 6MWT compared to healthy elderly subjects. 79 COPD patients and 24 healthy elderly subjects performed the 6MWT wearing an accelerometer attached to the trunk. The accelerometer features (walking intensity, cadence, and walking variability) and subject characteristics were assessed and compared between groups. Moreover, associations were sought with 6-min walk distance (6MWD) using multiple ordinary least squares (OLS) regression models. COPD patients walked with a significantly lower walking intensity, lower cadence and increased walking variability compared to healthy subjects. Walking intensity and height were the only two significant determinants of 6MWD in healthy subjects, explaining 85% of the variance in 6MWD. In COPD patients also age, cadence, walking variability measures and their interactions were included were significant determinants of 6MWD (total variance in 6MWD explained: 88%). COPD patients have an altered walking pattern during 6MWT compared to healthy subjects. These differences in walking pattern partially explain the lower 6MWD in patients with COPD.

  19. The J-2X Fuel Turbopump - Turbine Nozzle Low Cycle Fatigue Acceptance Rationale

    Science.gov (United States)

    Hawkins, Lakiesha V.; Duke, Gregory C.; Newman, Wesley R.; Reynolds, David C.

    2011-01-01

    The J-2X Fuel Turbopump (FTP) turbine, which drives the pump that feeds hydrogen to the J-2X engine for main combustion, is based on the J-2S design developed in the early 1970 s. Updated materials and manufacturing processes have been incorporated to meet current requirements. This paper addresses an analytical concern that the J-2X Fuel Turbine Nozzle Low Cycle Fatigue (LCF) analysis did not meet safety factor requirements per program structural assessment criteria. High strains in the nozzle airfoil during engine transients were predicted to be caused by thermally induced stresses between the vane hub, vane shroud, and airfoil. The heritage J-2 nozzle was of a similar design and experienced cracks in the same area where analysis predicted cracks in the J-2X design. Redesign options that did not significantly impact the overall turbine configuration were unsuccessful. An approach using component tests and displacement controlled fracture mechanics analysis to evaluate LCF crack initiation and growth rate was developed. The results of this testing and analysis were used to define the level of inspection on development engine test units. The programmatic impact of developing crack initiation/growth rate/arrest data was significant for the J-2X program. Final Design Certification Review acceptance logic will ultimately be developed utilizing this test and analytical data.

  20. Low frequency sound absorption of orifice plates, perforated plates and nozzles

    Science.gov (United States)

    Salikuddin, M.; Plumblee, H. E., Jr.

    1980-01-01

    Analyses of impulse time history data from acoustic transmission tests for conical nozzles attached to a pipe show internal reflections from the solid contraction and open area tend to cancel. To gain understanding of the opposing reflections, tests were conducted by replacing the conical nozzles with orifice plates. The primary variable was the open to solid area ratio. Internal reflection coefficient data reveal that, at an area ratio of 10-12%, the low frequency internal reflection is reduced from unity to about 0.2. Based on comparisons of far-field and internal data, acoustic energy is not conserved. Results are presented for complex reflection coefficient and far-field noise for a series of orifice and perforated plate configurations.

  1. An Automated DAKOTA and VULCAN-CFD Framework with Application to Supersonic Facility Nozzle Flowpath Optimization

    Science.gov (United States)

    Axdahl, Erik L.

    2015-01-01

    Removing human interaction from design processes by using automation may lead to gains in both productivity and design precision. This memorandum describes efforts to incorporate high fidelity numerical analysis tools into an automated framework and applying that framework to applications of practical interest. The purpose of this effort was to integrate VULCAN-CFD into an automated, DAKOTA-enabled framework with a proof-of-concept application being the optimization of supersonic test facility nozzles. It was shown that the optimization framework could be deployed on a high performance computing cluster with the flow of information handled effectively to guide the optimization process. Furthermore, the application of the framework to supersonic test facility nozzle flowpath design and optimization was demonstrated using multiple optimization algorithms.

  2. Patterns of skin prick test positivity in allergic patients: usefulness of a nationwide SPT chart review.

    Science.gov (United States)

    Larenas-Linnemann, D E; Fogelbach, G A Guidos; Alatorre, A Monteverde; Cruz, A Arias; Colín, D D Hernández; Pech, J A Luna; Hernández, A Medina; Imperial, D Alberto García; del Prado, M L Cid; Zapién, F J Linares; Huerta, R E; Martell, J A Ortega

    2011-01-01

    A previous survey on allergens used by Mexican allergists in their skin prick test (SPT) panel showed wide variation. Humidity varies in different zones of Mexico. This might lead to differences in natural exposure and allergic sensitisation throughout the country. We aim to describe the SPT sensitivity patterns in the different climatic zones in Mexico and to show the usefulness of a structured SPT chart-review including multiple clinics in obtaining these allergen sensitisation patterns. A retrospective, structured chart-review of SPT results was undertaken in allergy clinics throughout Mexico. Ratios of SPT positivity were calculated for individual allergens, per climatic zone and nation-wide. Per allergen group the most important allergens were identified. Statistically significant differences between zones and the nation-wide data were tested with Pearson's Chi-squares test. 4169 skin test charts were recollected. The most important allergens causing sensitisation were very similar in different zones, despite climate variation. The allergen with highest ratio of SPT positivity was Dermatophagoides pteronyssinus (51%), with trees (Ash-27%, Alder-22%, Oak19%), and Bermuda grass (26%) as second and third. In the hot zones (humid and dry) Aspergillus was statistically significant more frequently than in more temperate zones. Cockroaches thrive in big cities and humid zones and Mesquite and Poplar in dry zones. Weeds are less important. Mexico has its own SPT sensitisation pattern, which is different from America and Europe. A structured chart-review of SPT results is able to show this and might be a tool for allergists in other countries. Copyright © 2010 SEICAP. Published by Elsevier Espana. All rights reserved.

  3. Application of LBB to a nozzle-pipe interface

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Y.J.; Sohn, G.H.; Kim, Y.J. [and others

    1997-04-01

    Typical LBB (Leak-Before-Break) analysis is performed for the highest stress location for each different type of material in the high energy pipe line. In most cases, the highest stress occurs at the nozzle and pipe interface location at the terminal end. The standard finite element analysis approach to calculate J-Integral values at the crack tip utilizes symmetry conditions when modeling near the nozzle as well as away from the nozzle region to minimize the model size and simplify the calculation of J-integral values at the crack tip. A factor of two is typically applied to the J-integral value to account for symmetric conditions. This simplified analysis can lead to conservative results especially for small diameter pipes where the asymmetry of the nozzle-pipe interface is ignored. The stiffness of the residual piping system and non-symmetries of geometry along with different material for the nozzle, safe end and pipe are usually omitted in current LBB methodology. In this paper, the effects of non-symmetries due to geometry and material at the pipe-nozzle interface are presented. Various LBB analyses are performed for a small diameter piping system to evaluate the effect a nozzle has on the J-integral calculation, crack opening area and crack stability. In addition, material differences between the nozzle and pipe are evaluated. Comparison is made between a pipe model and a nozzle-pipe interface model, and a LBB PED (Piping Evaluation Diagram) curve is developed to summarize the results for use by piping designers.

  4. Temperature State of Noncooled Nozzle Adjutage of Liquid Rocket Engine

    Directory of Open Access Journals (Sweden)

    V. S. Zarubin

    2015-01-01

    Full Text Available The increasing specific impulse of the liquid rocket engine (LRE, which is designed to operate in space or in rarefied atmosphere, is directly related to the increasing speed of the combustion gases in the outlet section of the nozzle due to increasing nozzle expansion ratio. An intensity of the convective heat transfer of LRE combustion with the supersonic part of a nozzle shell in the first approximation is inversely proportional to the cross sectional area of gas dynamic path and reduces substantially as approaching to the outlet section of the nozzle.Therefore, in case of large nozzle expansion ratio the use of modern heat-resistant materials allows us to implement its outlet section as a thin-walled uncooled adjutage. This design solution results in reducing total weight of nozzle and decreasing overall preheat of LRE propellant used to cool the engine chamber. For a given diameter of the nozzle outlet section and pressure of combustion gases in this section, to make informed choices of permissible length for uncooled adjutage, it is necessary to have a reliable estimate of its thermal state on the steady-state LRE operation. A mathematical model of the nozzle shell heat transfer with the gas stream taking into account the heat energy transfer by convection and radiation, as well as by heat conduction along the generatrix of the shell enables this estimate.Quantitative analysis of given mathematical model showed that, because of the comparatively low pressure and temperature level of combustion gases, it is acceptable to ignore their own radiation and absorption capacity as compared with the convective heat intensity and the surface nozzle radiation. Thus, re-radiation of its internal surface portions is a factor of importance. Its taking into consideration is the main feature of the developed mathematical model.

  5. Probabilistic neural network with homogeneity testing in recognition of discrete patterns set.

    Science.gov (United States)

    Savchenko, A V

    2013-10-01

    The article is devoted to pattern recognition task with the database containing small number of samples per class. By mapping of local continuous feature vectors to a discrete range, this problem is reduced to statistical classification of a set of discrete finite patterns. It is demonstrated that the Bayesian decision under the assumption that probability distributions can be estimated using the Parzen kernel and the Gaussian window with a fixed variance for all the classes, implemented in the PNN, is not optimal in the classification of a set of patterns. We presented here the novel modification of the PNN with homogeneity testing which gives an optimal solution of the latter task under the same assumption about probability densities. By exploiting the discrete nature of patterns our modification prevents the well-known drawbacks of the memory-based approach implemented in both the PNN and the PNN with homogeneity testing, namely, low classification speed and high requirements to the memory usage. Our modification only requires the storage and processing of the histograms of input and training samples. We present the results of an experimental study in two practically important tasks: (1) the problem of Russian text authorship attribution with character n-grams features; and (2) face recognition with well-known datasets (AT&T, FERET and JAFFE) and comparison of color- and gradient-orientation histograms. Our results support the statement that the proposed network provides better accuracy (1%-7%) and is much more resistant to change of the smoothing parameter of Gaussian kernel function in comparison with the original PNN. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Recent Patterns in Shared Decision Making for Prostate-Specific Antigen Testing in the United States.

    Science.gov (United States)

    Fedewa, Stacey A; Gansler, Ted; Smith, Robert; Sauer, Ann Goding; Wender, Richard; Brawley, Otis W; Jemal, Ahmedin

    2018-03-01

    Previous studies report infrequent use of shared decision making for prostate-specific antigen (PSA) testing. It is unknown whether this pattern has changed recently considering increased emphasis on shared decision making in prostate cancer screening recommendations. Thus, the objective of this study is to examine recent changes in shared decision making. We conducted a retrospective cross-sectional study among men aged 50 years and older in the United States using 2010 and 2015 National Health Interview Survey (NHIS) data (n = 9,598). Changes in receipt of shared decision making were expressed as adjusted prevalence ratios (aPR) and 95% confidence intervals (CI). Analyses were stratified on PSA testing (recent [in the past year] or no testing). Elements of shared decision making assessed included the patient being informed about the advantages only, advantages and disadvantages, and full shared decision making (advantages, disadvantages, and uncertainties). Among men with recent PSA testing, 58.5% and 62.6% reported having received ≥1 element of shared decision making in 2010 and 2015, respectively ( P = .054, aPR = 1.04; 95% CI, 0.98-1.11). Between 2010 and 2015, being told only about the advantages of PSA testing significantly declined (aPR = 0.82; 95% CI, 0.71-0.96) and full shared decision making prevalence significantly increased (aPR = 1.51; 95% CI, 1.28-1.79) in recently tested men. Among men without prior PSA testing, 10% reported ≥1 element of shared decision making, which did not change with time. Between 2010 and 2015, there was no increase in shared decision making among men with recent PSA testing though there was a shift away from only being told about the advantages of PSA testing towards full shared decision making. Many men receiving PSA testing did not receive shared decision making. © 2018 Annals of Family Medicine, Inc.

  7. Effusive atomic oven nozzle design using an aligned microcapillary array

    International Nuclear Information System (INIS)

    Senaratne, Ruwan; Rajagopal, Shankari V.; Geiger, Zachary A.; Fujiwara, Kurt M.; Lebedev, Vyacheslav; Weld, David M.

    2015-01-01

    We present a simple and inexpensive design for a multichannel effusive oven nozzle which provides improved atomic beam collimation and thus extended oven lifetimes. Using this design, we demonstrate an atomic lithium source suitable for trapped-atom experiments. At a nozzle temperature of 525 °C, the collimated atomic beam flux directly after the nozzle is 1.2 × 10 14 atoms/s with a peak beam intensity greater than 5.0 × 10 16 atoms/s/sr. This suggests an oven lifetime of several decades of continuous operation

  8. Fuel injector nozzle for an internal combustion engine

    Science.gov (United States)

    Cavanagh, Mark S.; Urven, Jr., Roger L.; Lawrence, Keith E.

    2008-11-04

    A direct injection fuel injector includes a nozzle tip having a plurality of passages allowing fluid communication between an inner nozzle tip surface portion and an outer nozzle tip surface portion and directly into a combustion chamber of an internal combustion engine. A first group of the passages have inner surface apertures located substantially in a first common plane. A second group of the passages have inner surface apertures located substantially in at least a second common plane substantially parallel to the first common plane. The second group has more passages than the first group.

  9. Numerical study for two phase flow in the near nozzle region of turbine combustors

    International Nuclear Information System (INIS)

    Pervez, K.; Mushtaq, S.

    1999-01-01

    In the present study flow conditions in the near nozzle region of the combustion chamber have been investigated. There exists two-phase flow in this region. The overall performance and pollutant formation in the combustion chamber have been investigated. There exists two-phase flow in this region. The overall performance and pollutant formation in the combustion zone largely depends on the spray field in the near nozzle region the studies are conducted to determined the effects of multi jets on the flow pattern in the near nozzle region The phase doppler particle analyzer (PDPA) has been used to measure the velocities and sizes of the droplets. The flow field of two-phase liquid drop-air jets is formed from three injectors arranged in t line. Furthermore the two-phase flow field has been analyzed numerically also. The numerical analysis consists of two computational models, namely (i) 3 non-evaporating two-phase jets, (II) 3 evaporating two phase jets. The Eulerian-Eulerian approach in incorporated in both the numerical models. Since the flow is turbulent, a two-equation model (k-Epsilon) is implemented in the numerical analysis. Numerical solution of the conservation equation is obtained using PHOENICS computer code. Boundary conditions are provided from the experimental measurements. Numerical domain for the two models of the analysis starts at some distance (about 10 diameters of the injector orifice) where the atomization process is complete and droplet size and velocity could be measured experimentally. (author)

  10. Wind Tunnel Model Design for Sonic Boom Studies of Nozzle Jet with Shock Interactions

    Science.gov (United States)

    Cliff, Susan E.; Denison, Marie; Sozer, Emre; Moini-Yekta, Shayan

    2016-01-01

    NASA and Industry are performing vehicle studies of configurations with low sonic boom pressure signatures. The computational analyses of modern configuration designs have matured to the point where there is confidence in the prediction of the pressure signature from the front of the vehicle, but uncertainty in the aft signatures with often greater boundary layer effects and nozzle jet pressures. Wind tunnel testing at significantly lower Reynolds numbers than in flight and without inlet and nozzle jet pressures make it difficult to accurately assess the computational solutions of flight vehicles. A wind tunnel test in the NASA Ames 9- by 7-Foot Supersonic Wind Tunnel from Mach 1.6 to 2.0 will be used to assess the effects of shocks from components passing through nozzle jet plumes on the sonic boom pressure signature and provide datasets for comparison with CFD codes. A large number of high-fidelity numerical simulations of wind tunnel test models with a variety of shock generators that simulate horizontal tails and aft decks have been studied to provide suitable models for sonic boom pressure measurements using a minimally intrusive pressure rail in the wind tunnel. The computational results are presented and the evolution of candidate wind tunnel models is summarized and discussed in this paper.

  11. Prototype particulate stack sampler with single-cut nozzle and microcomputer calculating/display system

    International Nuclear Information System (INIS)

    Eler, J.C.; Littlefield, L.G.; Tillery, M.I.

    1979-01-01

    A prototype particulate stack sampler (PPSS) has been developed to improve on the existing EPA Method 5 sampling apparatus. Its primary features are (1) higher sampling rate (56 1/min); (2) display (on demand) of all required variables and calculated values by a microcomputer-based calculating and display system; (3) continuous stack gas moisture determination; (4) a virtual impactor nozzle with 3 μm mass median diameter cutpoint which collects fine and coarse particle fractions on separate glass fiber filters; (5) a variable-area inlet to maintain isokinetic sampling conditions; and (6) conversion to stainless steel components from the glass specified by EPA Method 5. The basic sampling techniques of EPA Method 5 have been retained; however, versatility in the form of optional in-stack filters and general modernization of the stack sampler have been provided in the prototype design. Laboratory testing with monodisperse dye aerosols has shown the present variable inlet, virtual impactor nozzle to have a collection efficiency which is less than 77% and significant wall losses. This is primarily due to lack of symmetry in this rectangular jet impactor and short transition lengths dictated by physical design constraints (required passage of the nozzle through a 7.6 cm (3 in) diameter stack port). Electronic components have shown acceptable service in laboratory testing although no field testing of the prototype under a broad range of temperature, humidity, and SO 2 concentration has been undertaken

  12. Trends in referral patterns, invasive management, and mortality in elderly patients referred for exercise stress testing.

    Science.gov (United States)

    Bouzas-Mosquera, Alberto; Peteiro, Jesús; Broullón, Francisco J; Calviño-Santos, Ramón; Mosquera, Víctor X; Barbeito-Caamaño, Cayetana; Larrañaga-Moreira, José María; Maneiro-Melón, Nicolás; Álvarez-García, Nemesio; Vázquez-Rodríguez, José Manuel

    2015-12-01

    Scarce data are available on the temporal patterns in clinical characteristics and outcomes of elderly patients referred for exercise stress testing. We aimed to assess the trends in baseline characteristics, tests results, referrals for invasive management, and mortality in these patients. We evaluated 11,192 patients aged ≥65years who were referred for exercise stress testing between January 1998 and December 2013. Calendar years were grouped into four quadrennia (1998-2001, 2002-2005, 2006-2009, and 2010-2013), and trends in clinical characteristics of the patients, type and results of the tests, referrals for invasive management, and mortality across the different periods were assessed. Despite a progressive decrease in the proportion of patients with non-interpretable baseline electrocardiograms or prior history of coronary artery disease, there was a gradual and marked increase in the use of cardiac imaging from 32.8% in 1998-2001 to 67.6% in 2010-2013 (pstress testing both without imaging (from 18.9 to 13.6%, pstress testing, we observed a decline over time in the probability of inducible myocardial ischemia, an increase in the use of cardiac imaging and in the rate of coronary revascularization, and an improvement in the survival rate at 1year. Copyright © 2015 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

  13. [Practice patterns in Mexican allergologists about skin tests with allergens during 2005-2006].

    Science.gov (United States)

    Larenas Linnemann, Désirée; Fogelbach, Guillermo Arturo Guidos; Cruz, Alfredo Arias

    2008-01-01

    Immunotherapy has been practiced since over a hundred years. The exact composition of the immunotherapy concentrate, with which the patient is treated, depends partly on the results of the skin prick tests applied to the allergic patient. As such, the effectiveness of the immunotherapy depends heavily on the quality of the skin prick test. The detailed recommendations for the realization of the skin prick tests have evolved and changed over the years, leading to multiple variations in its application in Mexico. We tried to get a picture of the daily practice patterns of the members of CMICA and CoMPedIA concerning the application of skin prick tests. Aquestionnaire was sent in various occasions to all members of the Colegio Mexicano de Inmunologia Clinica y Alergia (CMICA) and of the Colegio Mexicano de Pediatras, Especialistas en Inmunologia y Alergia (CoMPedIA). The results are presented descriptively and by calculation of the frequency/percentages of intervals of replies, in the case of numerical responses. A response rate of 61 (17%) was obtained of the College members, showing consistency in some replies but a wide variation in others, for example in the time certain medication has to be suspended before the execution of the skin prick test. Comparing the replies obtained with recent recommendations in international publications, some discrepancy can be detected. In some aspects of the survey there is coincidence of the skin test practices among the participants; however, in other items there is an important variation.

  14. A Study on the Influence of Fuel Pipe on Fuel Injection Characteristics of Each Nozzle Hole in Diesel Injector

    OpenAIRE

    Luo Fuqiang; Wang Chuqiao; Xue Fuying; Ye Bingjian; Wu Xiwen

    2016-01-01

    The inner diameter of high pressure fuel pipe has a significant effect on the fuel injection process and the performance of a diesel engine. The spray impact force of each nozzle hole of a conventional injection system of pump-line-nozzle for diesel engine (based on the spray momentum flux) and the injection pressure (on a fuel injection pump test rig) were measured. With varying fuel injection quantities and pump speed, the effects of the inner diameter of the high pressure fuel pipe on fuel...

  15. Cardiopulmonary exercise testing and second-line pulmonary function tests to detect obstructive pattern in symptomatic smokers with borderline spirometry.

    Science.gov (United States)

    Di Marco, Fabiano; Terraneo, Silvia; Job, Sara; Rinaldo, Rocco Francesco; Sferrazza Papa, Giuseppe Francesco; Roggi, Maria Adelaide; Santus, Pierachille; Centanni, Stefano

    2017-06-01

    The need for additional research on symptomatic smokers with normal spirometry has been recently emphasized. Albeit not meeting criteria for Chronic obstructive pulmonary disease (COPD) diagnosis, symptomatic smokers may experience activity limitation, evidence of airway disease, and exacerbations. We, therefore, evaluated whether symptomatic smokers with borderline spirometry (post-bronchodilator FEV 1 /FVC ratio between 5th to 20th percentile of predicted values) have pulmonary function abnormalities at rest and ventilatory constraints during exercise. 48 subjects (aged 60 ± 8 years, mean ± SD, 73% males, 16 healthy, and 17 symptomatic smokers) underwent cardiopulmonary exercise testing (CPET), body plethysmography, nitrogen single-breath washout test (N 2 SBW), lung diffusion for carbon monoxide (DLCO), and forced oscillation technique (FOT). Compared to healthy subjects, symptomatic smokers showed: 1) reduced breathing reserve (36 ± 17 vs. 49 ± 12%, P = 0.050); 2) exercise induced dynamic hyperinflation (-0.20 ± 0.17 vs. -0.03 ± 0.21 L, P = 0.043); 3) higher residual volume (158 ± 22 vs. 112 ± 22%, P spirometry, CPET and second-line pulmonary function tests may detect obstructive pattern. These subjects should be referred for second line testing, to obtain a diagnosis, or at least to clarify the mechanisms underlying symptoms. Whether the natural history of these patients is similar to COPD, and they deserve a similar therapeutic approach is worth investigating. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Remote-sensing satellite ground station evaluation using QPSK emulator with test pattern and PRBS generation

    Science.gov (United States)

    Srinivas, R.; Nithyanandan, L.; Umadevi, G.; Padmavathi, C. S.; Nayani, Radha

    2015-12-01

    In order to validate the performance of X-band (8000-8400 MHz) remote-sensing satellite receive chain, when the satellite is not in the vicinity of ground station, local loop end-end evaluation tests are mandatory to certify the RF downlink and base band receive chain performance. A customised test patterns compatible to IRS satellite series and PRBS sequence are generated, which are modulated using QPSK emulator to check and verify the satellite downlink chain performance. The design and implementation are done using novel digital techniques, and QPSK modulator is integrated with Test pattern and PRBS generator using state-of-art FPGAs. The QPSK emulator output is connected to high-speed fibre optic link which transfers the signal to near field bore-site antenna system. The test signal is thus up converted from 2557.5 MHz (S-band) frequency to required satellite carrier frequency of 8212.5 MHz; the emulated test signal is radiated from bore-site antenna, which simulates real-time satellite data transmission from space. Thus, the signal received by the parabolic dish antenna is down converted to 720 MHz, demodulated, bit synchronized, clock recovered, and frame synchronized. The evaluation of frame sync errors is done for good video data quality check. Also in the QPSK emulator, there is option of PRBS mode. Hence, using this option, the RF downlink and receive chain are evaluated for good Bit error rate (BER). The BER requirement is 1 error (tolerable) in 106 Million bits. The QPSK emulator has the provision to support different frequencies and data rates corresponding to all IRS satellite missions.

  17. Altitude Compensating Nozzle Transonic Performance Flight Demonstration, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Altitude compensating nozzles continue to be of interest for use on future launch vehicle boosters and upper stages because of their higher mission average Isp and...

  18. Fabrication of Composite Combustion Chamber/Nozzle for Fastrac Engine

    Science.gov (United States)

    Lawrence, T.; Beshears, R.; Burlingame, S.; Peters, W.; Prince, M.; Suits, M.; Tillery, S.; Burns, L.; Kovach, M.; Roberts, K.

    2001-01-01

    The Fastrac Engine developed by the Marshall Space Flight Center for the X-34 vehicle began as a low cost engine development program for a small booster system. One of the key components to reducing the engine cost was the development of an inexpensive combustion chamber/nozzle. Fabrication of a regeneratively cooled thrust chamber and nozzle was considered too expensive and time consuming. In looking for an alternate design concept, the Space Shuttle's Reusable Solid Rocket Motor Project provided an extensive background with ablative composite materials in a combustion environment. An integral combustion chamber/nozzle was designed and fabricated with a silica/phenolic ablative liner and a carbon/epoxy structural overwrap. This paper describes the fabrication process and developmental hurdles overcome for the Fastrac engine one-piece composite combustion chamber/nozzle.

  19. Characterization of Plasmadynamics within a Small Magnetic Nozzle

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal presents an experimental and theoretical research project intended to develop a more refined model of the underlying physics of magnetic nozzles. The...

  20. An evaluation of nozzle afterbody code - AR02P

    Science.gov (United States)

    Guyton, F. C.

    1986-07-01

    A project was undertaken to develop a computational fluid dynamics (CFD) code for use in nozzle afterbody analysis. Objectives were to create a three-dimensional code capable of calculating afterbody flows with accuracy quantitatively close to the Navier-Stokes solutions, but which would use significantly fewer computer resources. The resulting program coupled an inverse boundary-layer routine with an Euler code and incorporated a jet plume. Calculations were made for the axisymmetric AGARD 15-deg boattail afterbody with variations in nozzle pressure ratio for Mach numbers 0.6 and 0.9, and compared with experimental results. The code predicted drag changes with NPR which showed the proper variations, but the code did not provide the accuracy required for typical nozzle afterbody analysis. (NPR = Nozzle total pressure to free stream static pressure ratio.)

  1. Vibrational population distributions in nonequilibrium nozzle expansion flows

    Science.gov (United States)

    Watt, W. S.; Rich, J. W.

    1971-01-01

    Experimental measurements and theoretical calculations of the vibrational population distribution in nonequilibrium nozzle expansion flows of gas mixtures are reported. These studies were directed toward determining whether vibrational energy exchange pumping could lead to laser action on the vibrational bands of a diatomic molecule. Three different types of experiments were conducted. These showed (1) that vibrational energy was preferentially transferred from N2 to CO in supersonic nozzle flows containing these gases; (2) that under some conditions this vibrational energy exchange pumping mechanism created population inversions in the vibrational levels of CO; and (3) that at large expansion ratios the magnitude of these population inversions was sufficient to sustain lasing in the nozzle. A theoretical model was developed to calculate vibrational state population distributions in gas dynamic expansions of a mixture of diatomic gases. Although only isothermal calculations have been completed, these data indicate that population inversions are predicted for conditions similar to those obtained in the nozzle expansion flows.

  2. BOILING WATER REACTOR WITH FEED WATER INJECTION NOZZLES

    Science.gov (United States)

    Treshow, M.

    1963-04-30

    This patent covers the use of injection nozzles for pumping water into the lower ends of reactor fuel tubes in which water is converted directly to steam. Pumping water through fuel tubes of this type of boiling water reactor increases its power. The injection nozzles decrease the size of pump needed, because the pump handles only the water going through the nozzles, additional water being sucked into the tubes by the nozzles independently of the pump from the exterior body of water in which the fuel tubes are immersed. The resulting movement of exterior water along the tubes holds down steam formation, and thus maintains the moderator effectiveness, of the exterior body of water. (AEC)

  3. Fuel injection of coal slurry using vortex nozzles and valves

    Science.gov (United States)

    Holmes, Allen B.

    1989-01-01

    Injection of atomized coal slurry fuel into an engine combustion chamber is achieved at relatively low pressures by means of a vortex swirl nozzle. The outlet opening of the vortex nozzle is considerably larger than conventional nozzle outlets, thereby eliminating major sources of failure due to clogging by contaminants in the fuel. Control fluid, such as air, may be used to impart vorticity to the slurry and/or purge the nozzle of contaminants during the times between measured slurry charges. The measured slurry charges may be produced by a diaphragm pump or by vortex valves controlled by a separate control fluid. Fluidic circuitry, employing vortex valves to alternatively block and pass cool slurry fuel flow, is disclosed.

  4. Monitoring Approach to Evaluate the Performances of a New Deposition Nozzle Solution for DED Systems

    Directory of Open Access Journals (Sweden)

    Federico Mazzucato

    2017-05-01

    Full Text Available Abstract: In order to improve the process efficiency of a direct energy deposition (DED system, closed loop control systems can be considered for monitoring the deposition and melting processes and adjusting the process parameters in real-time. In this paper, the monitoring of a new deposition nozzle solution for DED systems is approached through a simulation-experimental comparison. The shape of the powder flow at the exit of the nozzle outlet and the spread of the powder particles on the deposition plane are analyzed through 2D images of the powder flow obtained by monitoring the powder depositions with a high-speed camera. These experimental results are then compared with data obtained through a Computational Fluid Dynamics model. Preliminary tests are carried out by varying powder, carrier, and shielding mass flow, demonstrating that the last parameter has a significant influence on the powder distribution and powder flow geometry.

  5. Postprandial Reactive Hypoglycaemia: Varying Presentation Patterns on Extended Glucose Tolerance Tests and Possible Therapeutic Approaches

    Directory of Open Access Journals (Sweden)

    Kevin Stuart

    2013-01-01

    Full Text Available Reactive hypoglycemia is a state characterised by sympathetic or neuroglycopenic symptoms associated with hypoglycaemia in the postprandial state resulting in considerable distress to the patient. It is our practice to carry out either extended glucose tolerance tests (eGTTs or mixed meal tests in these patients. We describe two patients who experienced hypoglycaemic symptoms early and late during eGTT. The patient who experienced symptoms early, in contrast to the patient who presented with late symptoms, did not possess any characteristics of the metabolic syndrome. Based on clinical symptoms, glucose, insulin, and free fatty acid (FFA levels, we speculate on possible mechanisms that may have accounted for each of their presentation patterns. We then discuss low glycaemic index diet which will be the mainstay of management.

  6. Complexity of cardiovascular rhythms during head-up tilt test by entropy of patterns.

    Science.gov (United States)

    Wejer, Dorota; Graff, Beata; Makowiec, Danuta; Budrejko, Szymon; Struzik, Zbigniew R

    2017-05-01

    The head-up tilt (HUT) test, which provokes transient dynamical alterations in the regulation of cardiovascular system, provides insights into complex organization of this system. Based on signals with heart period intervals (RR-intervals) and/or systolic blood pressure (SBP), differences in the cardiovascular regulation between vasovagal patients (VVS) and the healthy people group (CG) are investigated. Short-term relations among signal data represented symbolically by three-beat patterns allow to qualify and quantify the complexity of the cardiovascular regulation by Shannon entropy. Four types of patterns: permutation, ordinal, deterministic and dynamical, are used, and different resolutions of signal values in the the symbolization are applied in order to verify how entropy of patterns depends on a way in which values of signals are preprocessed. At rest, in the physiologically important signal resolution ranges, independently of the type of patterns used in estimates, the complexity of SBP signals in VVS is different from the complexity found in CG. Entropy of VVS is higher than CG what could be interpreted as substantial presence of noisy ingredients in SBP of VVS. After tilting this relation switches. Entropy of CG occurs significantly higher than VVS for SBP signals. In the case of RR-intervals and large resolutions, the complexity after the tilt becomes reduced when compared to the complexity of RR-intervals at rest for both groups. However, in the case of VVS patients this reduction is significantly stronger than in CG. Our observations about opposite switches in entropy between CG and VVS might support a hypothesis that baroreflex in VVS affects stronger the heart rate because of the inefficient regulation (possibly impaired local vascular tone alternations) of the blood pressure.

  7. Phoneme Error Pattern by Heritage Speakers of Spanish on an English Word Recognition Test.

    Science.gov (United States)

    Shi, Lu-Feng

    2017-04-01

    Heritage speakers acquire their native language from home use in their early childhood. As the native language is typically a minority language in the society, these individuals receive their formal education in the majority language and eventually develop greater competency with the majority than their native language. To date, there have not been specific research attempts to understand word recognition by heritage speakers. It is not clear if and to what degree we may infer from evidence based on bilingual listeners in general. This preliminary study investigated how heritage speakers of Spanish perform on an English word recognition test and analyzed their phoneme errors. A prospective, cross-sectional, observational design was employed. Twelve normal-hearing adult Spanish heritage speakers (four men, eight women, 20-38 yr old) participated in the study. Their language background was obtained through the Language Experience and Proficiency Questionnaire. Nine English monolingual listeners (three men, six women, 20-41 yr old) were also included for comparison purposes. Listeners were presented with 200 Northwestern University Auditory Test No. 6 words in quiet. They repeated each word orally and in writing. Their responses were scored by word, word-initial consonant, vowel, and word-final consonant. Performance was compared between groups with Student's t test or analysis of variance. Group-specific error patterns were primarily descriptive, but intergroup comparisons were made using 95% or 99% confidence intervals for proportional data. The two groups of listeners yielded comparable scores when their responses were examined by word, vowel, and final consonant. However, heritage speakers of Spanish misidentified significantly more word-initial consonants and had significantly more difficulty with initial /p, b, h/ than their monolingual peers. The two groups yielded similar patterns for vowel and word-final consonants, but heritage speakers made significantly

  8. C/C-SiC Composites for Nozzle of Solid Propellant Ramjet

    Directory of Open Access Journals (Sweden)

    WANG Lingling

    2017-01-01

    Full Text Available Carbon fiber reinforced carbon and silicon carbide matrix composites for nozzle inner of solid propellant ramjet were prepared by using the hybrid process of "chemical vapor infiltration + precursor impregnation pyrolysis (CVI+PIP". The microstructure, flexural and anti-ablation properties of the C/C-SiC composites and hydraulic test and rocket motor hot firing test for nozzle inner of solid propellant ramjet were comprehensively investigated. The results show that when the flexural strength of the composite reachs 197 MPa, the fracture damage behavior of the composites presents typical toughness mode.Also the composites has excellent anti-ablative property, i.e., linear ablation rate is only 0.0063 mm·s-1 after 200 s ablation. The C/C-SiC component have excellent integral bearing performance with the hydraulic bursting pressure of 6.5 MPa, and the high temperature combination property of the C/C-SiC composite nozzle inner is verified through motor hot firing of solid propellant ramjet.

  9. Rebuilding of Rothe's nozzle measurements with OpenFOAM software

    International Nuclear Information System (INIS)

    Arlemark, Erik; Nedea, Silvia; Markelov, Gennady

    2012-01-01

    In this paper the dsmcFoam solver is tested and validated for the the three main solver functionalities of 1) free-stream boundary conditions, 2) kinetic intermolecular collision including internal degrees of freedom and 3) gas/surface interactions. The free-stream utility was improved such that a spatially uniform field of particles gets inserted now yielding reliable results for the cells located close to these patches. Implementation of the collision models were validated for two test cases (monatomic gas mixtures and diatomic gas) by observing the equilibration of both the kinetic and internal energies. It was found that the present code had good agreement to the independent codes of HAWK and SMILE as well as to results by G. Bird. The validation of the present codes treatment for the gas/surface interactions was evaluated using the benchmark case of Rothe's nozzle measurements. Results show that the present version of dsmcFoam obtained good agreements for this case compared to the measurements of Rothe for density and temperature. It was also found that the Navier-Stokes solver of OpenFOAM produced reasonable results, even though the local Knudsen number of the flow exceeds the range of applicability for this method, Kn=0.1.

  10. Reverse flow through a large scale multichannel nozzle

    International Nuclear Information System (INIS)

    Duignan, M.R.; Nash, C.A.

    1992-01-01

    A database was developed for the flow of water through a scaled nozzle of a Savannah River Site reactor inlet plenum. The water flow in the nozzle was such that it ranged from stratified to water solid conditions. Data on the entry of air into the nozzle and plenum as a function of water flow are of interest in loss-of-coolant studies. The scaled nozzle was 44 cm long, had an entrance diameter of 95 mm, an exit opening of 58 mm x 356 mm, and an exit hydraulic diameter approximately equal to that of the inlet. Within the nozzle were three flow-straightening vanes which divided the flow path into four channels. All data were taken at steady-state and isothermal (300 K ± 1.5 K) conditions. During the reverse flow of water through the nozzle the point at which air begins to enter was predicted within 90% by a critical weir-flow calculation. The point of air entry into the plenum itself was found to be a function of flow conditions

  11. Jet Noise Scaling in Dual Stream Nozzles

    Science.gov (United States)

    Khavaran, Abbas; Bridges, James

    2010-01-01

    Power spectral laws in dual stream jets are studied by considering such flows a superposition of appropriate single-stream coaxial jets. Noise generation in each mixing region is modeled using spectral power laws developed earlier for single stream jets as a function of jet temperature and observer angle. Similarity arguments indicate that jet noise in dual stream nozzles may be considered as a composite of four single stream jets representing primary/secondary, secondary/ambient, transition, and fully mixed zones. Frequency filter are designed to highlight spectral contribution from each jet. Predictions are provided at an area ratio of 2.0--bypass ratio from 0.80 to 3.40, and are compared with measurements within a wide range of velocity and temperature ratios. These models suggest that the low frequency noise in unheated jets is dominated by the fully mixed region at all velocity ratios, while the high frequency noise is dominated by the secondary when the velocity ratio is larger than 0.80. Transition and fully mixed jets equally dominate the low frequency noise in heated jets. At velocity ratios less than 0.50, the high frequency noise from primary/bypass becomes a significant contributing factor similar to that in the secondary/ambient jet.

  12. The Graphic Pattern Generation Test in Healthy Aging and Alzheimer's Disease: Psychometric Properties and Normative Data

    Science.gov (United States)

    Sunderaraman, Preeti; Sokolov, Elisaveta; Cines, Sarah; Sullo, Elizabeth; Orly, Aidan; Lerer, Bianca; Karlawish, Jason; Huey, Edward; Cosentino, Stephanie

    2015-01-01

    Design fluency tests, commonly used in both clinical and research contexts to evaluate nonverbal concept generation, have the potential to offer useful information in the differentiation of healthy versus pathological aging. While normative data for older adults are available for multiple timed versions of this test, similar data have been unavailable for a previously published untimed task, the Graphic Pattern Generation Task (GPG). Time constraints common to almost all of the available design fluency tests may cloud interpretation of higher level executive abilities, for example in individuals with slow processing speed. The current study examined the psychometric properties of the GPG and presents normative data in a sample of 167 healthy older adults (OAs) and 110 individuals diagnosed with Alzheimer's disease (AD). Results suggest that a brief version of the GPG can be administered reliably, and that this short form has high test-retest and inter-rater reliability. Number of perseverations was higher in individuals with AD as compared to OAs. A cut-off score of 4 or more perseverations showed a moderate degree of sensitivity (76%) and specificity (37%) in distinguishing individuals with AD and OAs. Finally, perseverations were associated with nonmemory indices, underscoring the nonverbal nature of this error in OAs and individuals with AD. PMID:25679880

  13. Complex, Precision Cast Columbium Alloy Gas Turbine Engine Nozzles Coated to Resist Oxidation.

    Science.gov (United States)

    1980-04-01

    s..ed, UNCLASIFIED SECUIv CLASIFICATION OF THiS PAGCbam Do& bwa s Block No. 20 ABSTRACT R tals of Albany, Oregon was the casting subcontractor and...Specimen 25 18 Hollow Vane Segment 25 19 Solid Vane Segment 25 20 Steel Core Pull for Investment of Hollow Wax Patterns 26 21 Cast Solid Nozzles of C129Y...schematical I: in Figure 6. The environmental chamber is a clear quartz tube with stainless steel endcaps. The seals between the pullrods and endcaps and the

  14. Surface self-potential patterns related to transmissive fracture trends during a water injection test

    Science.gov (United States)

    DesRoches, A. J.; Butler, K. E.; MacQuarrie, K. TB

    2018-03-01

    Variations in self-potential (SP) signals were recorded over an electrode array during a constant head injection test in a fractured bedrock aquifer. Water was injected into a 2.2 m interval isolated between two inflatable packers at 44 m depth in a vertical well. Negative SP responses were recorded on surface corresponding to the start of the injection period with strongest magnitudes recorded in electrodes nearest the well. SP response decreased in magnitude at electrodes further from the well. Deflation of the packer system resulted in a strong reversal in the SP signal. Anomalous SP patterns observed at surface at steady state were found to be aligned with dominant fracture strike orientations found within the test interval. Numerical modelling of fluid and current flow within a simplified fracture network showed that azimuthal patterns in SP are mainly controlled by transmissive fracture orientations. The strongest SP gradients occur parallel to hydraulic gradients associated with water flowing out of the transmissive fractures into the tighter matrix and other less permeable cross-cutting fractures. Sensitivity studies indicate that increasing fracture frequency near the well increases the SP magnitude and enhances the SP anomaly parallel to the transmissive set. Decreasing the length of the transmissive fractures leads to more fluid flow into the matrix and into cross-cutting fractures proximal to the well, resulting in a more circular and higher magnitude SP anomaly. Results from the field experiment and modelling provide evidence that surface-based SP monitoring during constant head injection tests has the ability to identify groundwater flow pathways within a fractured bedrock aquifer.

  15. Wind tunnel measurement of spray drift from on-off controlled sprayer nozzles

    DEFF Research Database (Denmark)

    Lund, Ivar; Jensen, Peter Kryger; Miller, Paul

    wide surface area with a length of 200 mm. The test was conducted in the wind tunnel at Silsoe Spray Applications Unit in the UK. The measurements consisted of two test series; airborne drift was collected on polyethylene lines more than 375 mm away from the centerline of the nozzle and ground deposits...... and arranged to deliver a pulse of spray using the WeedSeeker valve. The tests were conducted to determine accumulated spray deposit at different crosswind and forward speeds. In general, the deposits, especially those measured downwind close to the target zone showed significant increase as the crosswind...

  16. Comparison of the commercial color LCD and the medical monochrome LCD using randomized object test patterns.

    Science.gov (United States)

    Wu, Jay; Wu, Tung H; Han, Rou P; Chang, Shu J; Shih, Cheng T; Sun, Jing Y; Hsu, Shih M

    2012-01-01

    Workstations and electronic display devices in a picture archiving and communication system (PACS) provide a convenient and efficient platform for medical diagnosis. The performance of display devices has to be verified to ensure that image quality is not degraded. In this study, we designed a set of randomized object test patterns (ROTPs) consisting of randomly located spheres with various image characteristics to evaluate the performance of a 2.5 mega-pixel (MP) commercial color LCD and a 3 MP diagnostic monochrome LCD in several aspects, including the contrast, resolution, point spread effect, and noise. The ROTPs were then merged into 120 abdominal CT images. Five radiologists were invited to review the CT images, and receiver operating characteristic (ROC) analysis was carried out using a five-point rating scale. In the high background patterns of ROTPs, the sensitivity performance was comparable between both monitors in terms of contrast and resolution, whereas, in the low background patterns, the performance of the commercial color LCD was significantly poorer than that of the diagnostic monochrome LCD in all aspects. The average area under the ROC curve (AUC) for reviewing abdominal CT images was 0.717±0.0200 and 0.740±0.0195 for the color monitor and the diagnostic monitor, respectively. The observation time (OT) was 145±27.6 min and 127±19.3 min, respectively. No significant differences appeared in AUC (p = 0.265) and OT (p = 0.07). The overall results indicate that ROTPs can be implemented as a quality control tool to evaluate the intrinsic characteristics of display devices. Although there is still a gap in technology between different types of LCDs, commercial color LCDs could replace diagnostic monochrome LCDs as a platform for reviewing abdominal CT images after monitor calibration.

  17. Comparison of the commercial color LCD and the medical monochrome LCD using randomized object test patterns.

    Directory of Open Access Journals (Sweden)

    Jay Wu

    Full Text Available Workstations and electronic display devices in a picture archiving and communication system (PACS provide a convenient and efficient platform for medical diagnosis. The performance of display devices has to be verified to ensure that image quality is not degraded. In this study, we designed a set of randomized object test patterns (ROTPs consisting of randomly located spheres with various image characteristics to evaluate the performance of a 2.5 mega-pixel (MP commercial color LCD and a 3 MP diagnostic monochrome LCD in several aspects, including the contrast, resolution, point spread effect, and noise. The ROTPs were then merged into 120 abdominal CT images. Five radiologists were invited to review the CT images, and receiver operating characteristic (ROC analysis was carried out using a five-point rating scale. In the high background patterns of ROTPs, the sensitivity performance was comparable between both monitors in terms of contrast and resolution, whereas, in the low background patterns, the performance of the commercial color LCD was significantly poorer than that of the diagnostic monochrome LCD in all aspects. The average area under the ROC curve (AUC for reviewing abdominal CT images was 0.717±0.0200 and 0.740±0.0195 for the color monitor and the diagnostic monitor, respectively. The observation time (OT was 145±27.6 min and 127±19.3 min, respectively. No significant differences appeared in AUC (p = 0.265 and OT (p = 0.07. The overall results indicate that ROTPs can be implemented as a quality control tool to evaluate the intrinsic characteristics of display devices. Although there is still a gap in technology between different types of LCDs, commercial color LCDs could replace diagnostic monochrome LCDs as a platform for reviewing abdominal CT images after monitor calibration.

  18. Flow regime effects on non-cavitating injection nozzles over spray behavior

    Energy Technology Data Exchange (ETDEWEB)

    Payri, R., E-mail: rpayri@mot.upv.e [CMT-Motores Termicos, Universidad Politecnica de Valencia, Camino de Vera s/n, Valencia E-46022 (Spain); Salvador, F.J.; Gimeno, J.; Novella, R. [CMT-Motores Termicos, Universidad Politecnica de Valencia, Camino de Vera s/n, Valencia E-46022 (Spain)

    2011-02-15

    This paper deals with the influence of flow regime (laminar, transition or turbulent) on the internal flow behavior, and how it affects the spray development in diesel nozzles. In particular, the research described here aims at studying and quantifying the internal flow regime effects on the spray behavior. With this purpose, internal flow results, based on mass flow rate and momentum flux measurements performed on three different tapered nozzles and which helped to determine the flow regime, has been taken into account as a point of departure for the spray behavior analysis. Thus, in this work, spray macroscopic visualization tests have been performed and analyzed which clearly revealed a change in the behavior of the angle and penetration of the spray related to the change of the flow nature. Moreover, with all the experimental data available, it has been possible to relate macroscopic parameters of the spray with those describing the internal flow (momentum and effective velocity) or the geometry of the nozzle (length or diameter) through correlations.

  19. Determination of welding parameters for execution of weld overlayer on PWR nuclear reactor nozzles

    International Nuclear Information System (INIS)

    Ribeiro, Gabriela M.; Lima, Luciana I.; Quinan, Marco A.; Schvartzman, Monica M.

    2009-01-01

    In the PWR reactors, nickel based dissimilar welds have been presented susceptibilities the stress corrosion (S C). For the mitigation the problem a deposition of weld layers on the external surface of the nozzle is an alternative, viewing to provoke the compression of the region subjected to S C. This paper presents a preliminary study on the determination of welding parameters to obtain these welding overlayers. Welding depositions were performed on a test piece welded with nickel 182 alloy, simulating the conditions of a nozzle used in a PWR nuclear power plant. The welding process was the GTAW (Gas Tungsten Arc Welding), and a nickel 52 alloy as addition material. The overlayers were performed on the base metals, carbon steel an stainless steel, changing the welding parameters and verifying the the time of each weld filet. After that, the samples were micro structurally characterized. The macro structures and the microstructures obtained through optical microscopy and Vickers microhardness are presented. The preliminary results make evident the good weld quality. However, a small weld parameters influence used in the base material microstructure (carbon steel and stainless steel). The obtained results in this study will be used as reference in the construction of a mock up which will simulate all the conditions of a pressurizer nozzle of PWR reactor

  20. Ultra-High Speed Visualization of the Flashing Instability in Micron Size Nozzles under Vacuum Conditions

    KAUST Repository

    Alghamdi, Tariq A.

    2017-11-01

    I visualized the flash-boiling atomization of liquid jets released into a low pressure environment at frame rates of up to five million frames per second. Such a high temporal resolution allowed us to observe for the first time the bubble expansion mechanism that atomizes the jet. To visualize the dynamics in detail, I focused closely to the outflow of the nozzle using a long distance microscope objective. I documented an abrupt transition from a laminar to a fully external flashing jet by systematically reducing the ambient pressure. I performed experiments with different volatile liquids and using nozzles with different inner diameters. The inner diameters of the nozzles varied from 30 to 480 . Perfluorohexane (PFnH) was our main working fluid, but also methanol, ethanol and 1-bromopropane were tested. Surprisingly, minimum intensity profiles revealed spray angles close to ~360°, meaning drops are ejected in all directions. Also, I measured speeds of bubble expansion up to 140 m/s. That is 45 times faster than the upper bound for inertial growth speed in complete vacuum from the Rayleigh-Plesset equation. I also calculated the trajectories of the ejected droplets as well as the drop speed distribution using particle tracking. I expect that our results bring new insight into the flash-boiling atomization mechanism.

  1. Ultrasonic Phased Array Assessment of the Interference Fit and Leak Path of the North Anna Unit 2 Control Rod Drive Mechanism Nozzle 63 with Destructive Validation

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, Susan L.; Cinson, Anthony D.; MacFarlan, Paul J.; Hanson, Brady D.; Mathews, Royce

    2012-08-01

    The objective of this investigation was to evaluate the efficacy of ultrasonic testing (UT) for primary water leak path assessments of reactor pressure vessel (RPV) upper head penetrations. Operating reactors have experienced leakage when stress corrosion cracking of nickel-based alloy penetrations allowed primary water into the annulus of the interference fit between the penetration and the low-alloy steel RPV head. In this investigation, UT leak path data were acquired for an Alloy 600 control rod drive mechanism nozzle penetration, referred to as Nozzle 63, which was removed from the North Anna Unit 2 reactor when the RPV head was replaced in 2002. In-service inspection prior to the head replacement indicated that Nozzle 63 had a probable leakage path through the interference fit region. Nozzle 63 was examined using a phased-array UT probe with a 5.0-MHz, eight-element annular array. Immersion data were acquired from the nozzle inner diameter surface. The UT data were interpreted by comparing to responses measured on a mockup penetration with known features. Following acquisition of the UT data, Nozzle 63 was destructively examined to determine if the features identified in the UT examination, including leakage paths and crystalline boric acid deposits, could be visually confirmed. Additional measurements of boric acid deposit thickness and low-alloy steel wastage were made to assess how these factors affect the UT response. The implications of these findings for interpreting UT leak path data are described.

  2. The touchscreen operant platform for testing working memory and pattern separation in rats and mice.

    Science.gov (United States)

    Oomen, Charlotte A; Hvoslef-Eide, Martha; Heath, Christopher J; Mar, Adam C; Horner, Alexa E; Bussey, Timothy J; Saksida, Lisa M

    2013-10-01

    The automated touchscreen operant chamber for rats and mice allows for the assessment of multiple cognitive domains within the same testing environment. This protocol presents the location discrimination (LD) task and the trial-unique delayed nonmatching-to-location (TUNL) task, which both assess memory for location. During these tasks, animals are trained to a predefined criterion during ∼20-40 daily sessions. In LD sessions, touching the same location on the screen is rewarded on consecutive trials, followed by a reversal of location-reward contingencies. TUNL, a working memory task, requires animals to 'nonmatch' to a sample location after a delay. In both the LD and TUNL tasks, spatial similarity can be varied, allowing assessment of pattern separation ability, a function that is thought to be performed by the dentate gyrus (DG). These tasks are therefore particularly useful in animal models of hippocampal, and specifically DG, function, but they additionally permit discernment of changes in pattern separation from those in working memory.

  3. High precision carbon-interspaced antiscatter grids: Performance testing and moiré pattern analysis

    Science.gov (United States)

    Lee, S. J.; Cho, H. S.; Oh, J. E.; Choi, S. I.; Cho, H. M.; Park, Y. O.; Hong, D. K.; Lee, M. S.; Yang, Y. J.; Je, U. K.; Kim, D. S.; Lee, H. K.

    2011-10-01

    Recently, we have developed high precision carbon-interspaced antiscatter grids to be suitable for digital radiography (DR) adopting a precise sawing process. For systematic evaluation of the grid performance, we prepared several sample grids having different grid frequencies (4.0-8.5 lines/mm) and grid ratios (5:1-10:1) and established a well-controlled test condition based upon the IEC standard. In this paper, we presented the performance characteristics of the carbon-interspaced grids in terms of the transmission of primary radiation ( Tp), the transmission of scattered radiation ( Ts), the transmission of total radiation ( Tt), contrast improvement factor ( Cif), and Bucky factor ( B). We also described the grid line artifact, known as a moiré pattern, which may be the most critical problem to be solved for the successful grid use in DR. We examined the factors that affect the moiré pattern by integrating the sample grids with an a-Se based flat panel detector having a 139 μm×139 μm pixel size.

  4. The Hopkins Verbal Learning Test: an in-depth analysis of recall patterns.

    Science.gov (United States)

    Grenfell-Essam, Rachel; Hogervorst, Eef; W Rahardjo, Tri Budi

    2018-04-01

    One of the earliest signs of dementia is memory issues and verbal word lists, such as the Hopkins Verbal Learning Test (HVLT), are successfully used for screening. To gain insight in how memory is affected in dementia, and to further improve the efficacy of the HVLT, in-depth analysis of the recall patterns of dementia cases and controls was conducted. Dementia cases and controls were matched for factors that can affect performance, such as age, gender and education level. Word frequency, syllable length, and orthographic neighbourhood size did not differ in the Indonesian version of the HVLT, nor did these characteristics affect recall. However dementia cases showed consistent and poor recall across the three trials; with the worst recall for the "human shelter" category and best recall for the "animals" category. Dementia cases also showed impaired accessibility of all categories with reduced subsequent recall from accessed categories and reduced primacy and recency levels. Finally, dementia cases exhibited lower levels of re-remembering and recalling new words, and higher levels of immediate forgetting and never recalling words. It was concluded that utilising the extra information provided by the in-depth analyses of the recall patterns could be beneficial to improve dementia screening.

  5. Improvements in the UT Inspection of vessel nozzles. Array application

    International Nuclear Information System (INIS)

    Tanarro, A.; Garcia, A.; Izquierdo, J.

    1998-01-01

    Automatic ultrasonic inspection of certain components in nuclear power plants, together with problems related to access of same, result in other difficulties due to the complexity of their geometry and the apparent orientation of possible defects. Array technology, recently developed on the basis of the theoretical principals of phased array technique, has meant that it is now possible to advance in the characterisation, localisation, and sizing of the defects in these components. This has been possible thanks to the discovery of synthetic materials which have allowed us to design and manufacture a new group of ultrasonic transducers. To these we may add new developments in electronics and computer sciences which have facilitated the building of high-powered control systems. This report discusses the work carried out by Tecnatom and Iberdrola in the field of automatic ultrasonic inspection of the vessel nozzles by means of array technology in the BWR at the Cofrentes Nuclear Power Station. The aims of this work were: - To facilitate the detection, characterisation, sizing and positioning of defects - To simplify and improve ultrasonic inspection in order to reduce acquisition times and the cost of same In order to achieve these results the following items were developed: - New array transducers were designed and manufactured - A new data acquisition system was developed - New programs for analysing data and for simulating ultrasonic testing was developed - The results have been validated in mock up. (Author)

  6. The Effect of Bypass Nozzle Exit Area on Fan Aerodynamic Performance and Noise in a Model Turbofan Simulator

    Science.gov (United States)

    Hughes, Christopher E.; Podboy, Gary, G.; Woodward, Richard P.; Jeracki, Robert, J.

    2013-01-01

    The design of effective new technologies to reduce aircraft propulsion noise is dependent on identifying and understanding the noise sources and noise generation mechanisms in the modern turbofan engine, as well as determining their contribution to the overall aircraft noise signature. Therefore, a comprehensive aeroacoustic wind tunnel test program was conducted called the Fan Broadband Source Diagnostic Test as part of the NASA Quiet Aircraft Technology program. The test was performed in the anechoic NASA Glenn 9- by 15-Foot Low Speed Wind Tunnel using a 1/5 scale model turbofan simulator which represented a current generation, medium pressure ratio, high bypass turbofan aircraft engine. The investigation focused on simulating in model scale only the bypass section of the turbofan engine. The test objectives were to: identify the noise sources within the model and determine their noise level; investigate several component design technologies by determining their impact on the aerodynamic and acoustic performance of the fan stage; and conduct detailed flow diagnostics within the fan flow field to characterize the physics of the noise generation mechanisms in a turbofan model. This report discusses results obtained for one aspect of the Source Diagnostic Test that investigated the effect of the bypass or fan nozzle exit area on the bypass stage aerodynamic performance, specifically the fan and outlet guide vanes or stators, as well as the farfield acoustic noise level. The aerodynamic performance, farfield acoustics, and Laser Doppler Velocimeter flow diagnostic results are presented for the fan and four different fixed-area bypass nozzle configurations. The nozzles simulated fixed engine operating lines and encompassed the fan stage operating envelope from near stall to cruise. One nozzle was selected as a baseline reference, representing the nozzle area which would achieve the design point operating conditions and fan stage performance. The total area change from

  7. A quantitative test of population genetics using spatiogenetic patterns in bacterial colonies.

    Science.gov (United States)

    Korolev, Kirill S; Xavier, João B; Nelson, David R; Foster, Kevin R

    2011-10-01

    It is widely accepted that population-genetics theory is the cornerstone of evolutionary analyses. Empirical tests of the theory, however, are challenging because of the complex relationships between space, dispersal, and evolution. Critically, we lack quantitative validation of the spatial models of population genetics. Here we combine analytics, on- and off-lattice simulations, and experiments with bacteria to perform quantitative tests of the theory. We study two bacterial species, the gut microbe Escherichia coli and the opportunistic pathogen Pseudomonas aeruginosa, and show that spatiogenetic patterns in colony biofilms of both species are accurately described by an extension of the one-dimensional stepping-stone model. We use one empirical measure, genetic diversity at the colony periphery, to parameterize our models and show that we can then accurately predict another key variable: the degree of short-range cell migration along an edge. Moreover, the model allows us to estimate other key parameters, including effective population size (density) at the expansion frontier. While our experimental system is a simplification of natural microbial community, we argue that it constitutes proof of principle that the spatial models of population genetics can quantitatively capture organismal evolution.

  8. Surveying Indian gay men for coping skills and HIV testing patterns using the internet.

    Science.gov (United States)

    Jethwani, K S; Mishra, S V; Jethwani, P S; Sawant, N S

    2014-01-01

    Surveying vulnerable and incarcerated populations is often challenging. Newer methods to reach and collect sensitive information in a safe, secure, and valid manner can go a long way in addressing this unmet need. Homosexual men in India live with inadequate social support, marginalization, and lack legal recognition. These make them less reachable by public health agencies, and make them more likely to continue with high-risk behaviors, and contract human immunodeficiency virus (HIV). To understand coping skills and HIV testing patterns of homosexual men versus heterosexual men. An internet based study using a secure web platform and an anonymised questionnaire. The brief COPE Inventory was used to assess coping styles. A total of 124 respondents were studied. Homosexual men used negative coping skills such as behavioral disengagement and tested for HIV significantly more often than heterosexual men. Heterosexual respondents used positive coping skills more often. The most commonly used coping skill by heterosexual men was instrumental coping and by homosexual men was acceptance. Overall, homosexual men used negative coping mechanisms, like behavioral disengagement more often. The Indian family structure and social support is probably responsible for heterosexual men's over-reliance on instrumental coping, while resulting in disengagement in homosexuals. The lack of legal and social recognition of homosexuality has negatively impacted lives of gay men in India. This is strongly linked to harmful psychological and public health implications for HIV prevention and mental health for homosexual men.

  9. Surveying Indian gay men for coping skills and HIV testing patterns using the internet

    Directory of Open Access Journals (Sweden)

    K S Jethwani

    2014-01-01

    Full Text Available Background: Surveying vulnerable and incarcerated populations is often challenging. Newer methods to reach and collect sensitive information in a safe, secure, and valid manner can go a long way in addressing this unmet need. Homosexual men in India live with inadequate social support, marginalization, and lack legal recognition. These make them less reachable by public health agencies, and make them more likely to continue with high-risk behaviors, and contract human immunodeficiency virus (HIV. Aims: To understand coping skills and HIV testing patterns of homosexual men versus heterosexual men. Materials and Methods: An internet based study using a secure web platform and an anonymised questionnaire. The brief COPE Inventory was used to assess coping styles. Results: A total of 124 respondents were studied. Homosexual men used negative coping skills such as behavioral disengagement and tested for HIV significantly more often than heterosexual men. Heterosexual respondents used positive coping skills more often. The most commonly used coping skill by heterosexual men was instrumental coping and by homosexual men was acceptance. Discussion: Overall, homosexual men used negative coping mechanisms, like behavioral disengagement more often. The Indian family structure and social support is probably responsible for heterosexual men′s over-reliance on instrumental coping, while resulting in disengagement in homosexuals. Conclusion: The lack of legal and social recognition of homosexuality has negatively impacted lives of gay men in India. This is strongly linked to harmful psychological and public health implications for HIV prevention and mental health for homosexual men.

  10. Muscle activation patterns related to diabetic neuropathy in elderly subjects: A Functional Reach Test study.

    Science.gov (United States)

    Maranesi, E; Di Nardo, F; Rabini, R A; Ghetti, G G; Burattini, L; Mercante, O; Fioretti, S

    2016-02-01

    This study was designed to assess, in healthy elderly, non-neuropathic and neuropathic diabetic subjects, the activation patterns of the main muscles involved in the Functional Reach Test, a well-recognized method to identify elderly subjects at risk of balance impairments. Surface electromyographic analysis of Sternocleidomastoideus, Rectus Abdominis, Erectores Spinae at L4 level, Rectus Femoris, Hamstrings, Tibialis Anterior and Soleus was performed in 10 healthy, 10 diabetic non-neuropathic and 10 diabetic neuropathic subjects. Results showed that in every group the first motor is Tibialis Anterior, that is recruited before the start of the test. An earlier activation of Tibialis Anterior (Pmovement timing and to compensate for the delay in the recruitment of the motor units. This anticipation might be involved in the altered postural control with increased balance impairment detected in diabetic neuropathic patients, and thereby it might also be proposed as an index of neuropathy, evidenced in a simple and non-invasive manner. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. System for installing a steam generator nozzle dam

    International Nuclear Information System (INIS)

    McDonald, F.X.; Weisel, E.M.; Schukei, G.E.

    1991-01-01

    This patent describes a system for installing a nozzle dam in a nuclear steam generator having a head including a head internal surface, a manway penetrating the head, and a nozzle penetrating the head. It comprises a manipulator adapted to be passed through the manway and having one end adapted to be attached remotely to the head internal surface and a free end including a clamp member; nozzle dam segments, each segment sized to pass through the manway and having means thereon for engaging at least one other segment, the segments when fully engaged to each other forming a dam subassembly sized to pass into and seat against the nozzle; and means for controlling the manipulator while the one end is attached to the head internal surface, such that the clamp member grasps and supports one of the dam segments within the head until the subassembly is formed within the head, and then translates the dam subassembly within the head until the dam subassembly seats within the nozzle

  12. Low Bone Mineral Density Risk Factors and Testing Patterns in Institutionalized Adults with Intellectual and Developmental Disabilities

    Science.gov (United States)

    Hess, Mailee; Campagna, Elizabeth J.; Jensen, Kristin M.

    2018-01-01

    Background: Adults with intellectual or developmental disability (ID/DD) have multiple risks for low bone mineral density (BMD) without formal guidelines to guide testing. We sought to identify risk factors and patterns of BMD testing among institutionalized adults with ID/DD. Methods: We evaluated risk factors for low BMD (Z-/T-score < -1) and…

  13. Antibiotic Resistant Pattern of Helicobacter Pylori Infection Based on Molecular Tests in Laos.

    Science.gov (United States)

    Vannarath, Sengdao; Vilaichone, Ratha-Korn; Rasachak, Bouachanh; Mairiang, Pisaln; Yamaoka, Yoshio; Mahachai, Varocha

    2016-01-01

    The efficacy of standard treatment of Helicobacter pylori (H. pylori) is declining because of antibiotic resistance. Clarithromycin resistance is also increasing in many Asian countries. The aim of this study was to determine the antibiotic susceptibility patterns of H. pylori infection and clinical association in Laos. A total of 329 Lao dyspeptic patients who underwent gastroscopy at Mahosot Hospital, Vientiane, Laos during December 2010-March 2012 were enrolled in this study. During gastroscopy, 4 biopsies were collected (2 each from the antrum and body) for CLO-test and histopathology. Only the positive CLO-test gastric tissues was stored at -80° in a freezer until DNA was extracted and a GenoType®HelicoDR test was conducted for detecting mutations in the rrl gene encoding 23S rRNA (clarithromycin resistance) and mutations in gyrA gene (fluoroquinolone resistance) . Of the total, 119 Lao patients (36.2%) were infected with H. pylori including 59 males (49.6%) and 60 females (50.4%) with a mean age of 46 years. Clarithromycin and fluoroquinolone resistance of H. pylori infection was demonstrated in 15 (12.6%) and 16 strains (13.4%) respectively. In clarithromycin resistance, the number of patients who had education above primary school and BMI≥ 25 kg/m2 were significantly higher than those who had education below primary school and BMILao was significantly higher than those of non- lowland (highland and midland) Lao ethnic groups (16.7% vs 0%, P-value= 0.039). H. pylori infections remain common in Laos. Clarithromycin and fluoroquinolone resistance with H. pylori infection are growing problems. Education above primary school and BMI ≥ 25 kg/m2 might be predictors for clarithromycin resistance and lowland Lao ethnicity might be predictors for fluoroquinolone resistance with H. pylori infection in Laos.

  14. Using landscape ecology to test hypotheses about large-scale abundance patterns in migratory birds

    Science.gov (United States)

    Flather, C.H.; Sauer, J.R.

    1996-01-01

    The hypothesis that Neotropical migrant birds may be undergoing widespread declines due to land use activities on the breeding grounds has been examined primarily by synthesizing results from local studies. Growing concern for the cumulative influence of land use activities on ecological systems has heightened the need for large-scale studies to complement what has been observed at local scales. We investigated possible landscape effects on Neotropical migrant bird populations for the eastern United States by linking two large-scale inventories designed to monitor breeding-bird abundances and land use patterns. The null hypothesis of no relation between landscape structure and Neotropical migrant abundance was tested by correlating measures of landscape structure with bird abundance, while controlling for the geographic distance among samples. Neotropical migrants as a group were more 'sensitive' to landscape structure than either temperate migrants or permanent residents. Neotropical migrants tended to be more abundant in landscapes with a greater proportion of forest and wetland habitats, fewer edge habitats, large forest patches, and with forest habitats well dispersed throughout the scene. Permanent residents showed few correlations with landscape structure and temperate migrants were associated with habitat diversity and edge attributes rather than with the amount, size, and dispersion of forest habitats. The association between Neotropical migrant abundance and forest fragmentation differed among physiographic strata, suggesting that land-scape context affects observed relations between bird abundance and landscape structure. Finally, associations between landscape structure and temporal trends in Neotropical migrant abundance were negatively correlated with forest habitats. These results suggest that extrapolation of patterns observed in some landscapes is not likely to hold regionally, and that conservation policies must consider the variation in landscape

  15. A finite element approach for predicting nozzle admittances

    Science.gov (United States)

    Sigman, R. K.; Zinn, B. T.

    1983-01-01

    A finite element method is used to predict the admittances of axisymmetric nozzles. It is assumed that the flow in the nozzle is isentropic and the disturbances are small so that linear analyses apply. An approximate, two dimensional compressible model is used to describe the steady flow in the nozzle. The propagation of acoustic disturbances is governed by the complete linear wave equation. The differential form of the acoustic equation is transformed to an integral equation by using Galerkin's method, and Green's theorem is applied so that the acoustic boundary conditions can be introduced through the boundary residuals. The boundary conditions are described for both straight and curved sonic lines. A two dimensional FEM with linear elements is used to solve the acoustic equation. A one dimensional FEM is also used to solve the reduced equation of Crocco, and the solution verifies the sufficiency of the boundary residual formulation. Comparison between computed admittances and experimental data is shown to be quite good.

  16. Theoretical determination of nozzle admittances using a finite element approach

    Science.gov (United States)

    Sigman, R. K.; Zinn, B. T.

    1980-01-01

    A finite element method is used to predict the admittances of axisymmetric nozzles. It is assumed that the flow in the nozzle is isentropic and irrotational, and the disturbances are small so that linear analyses apply. An approximate, two dimensional compressible model is used to describe the steady flow in the nozzle. The propagation of acoustic disturbances is governed by the complete linear wave equation. The differential form of the acoustic equation is transformed to an integral equation using Galerkin's method, and Green's theorem is applied so that the acoustic boundary conditions can be introduced through the boundary residuals. A two-dimensional FEM using linear elements is used to solve the acoustic equation. A one dimensional FEM is also used to solve the reduced equation of Crocco, and the solution verifies the sufficiency of the boundary residual formulation. Comparison between computed admittances and experimental data is shown to be quite good.

  17. Top-nozzle mounted replacement guide pin assemblies

    International Nuclear Information System (INIS)

    Gilmore, C.B.; Andrews, W.H.

    1993-01-01

    A replacement guide pin assembly is provided for aligning a nuclear fuel assembly with an upper core plate of a nuclear reactor core. The guide pin assembly includes a guide pin body having a radially expandable base insertable within a hole in the top nozzle, a ferrule insertable within the guide pin base and capable of imparting a radially and outwardly directed force on the expandable base to expand it within the hole of the top nozzle and thereby secure the guide pin body to the top nozzle in response to a predetermined displacement of the ferrule relative to the guide pin body along its longitudinal axis, and a lock screw interfitted with the ferrule and threaded into the guide pin body so as to produce the predetermined displacement of the ferrule. (author)

  18. Effect of nozzle geometry for swirl type twin-fluid water mist nozzle on the spray characteristic

    International Nuclear Information System (INIS)

    Yoon, Soon Hyun; Kim, Do Yeon; Kim, Dong Keon; Kim, Bong Hwan

    2011-01-01

    Experimental investigations on the atomization characteristics of twin-fluid water mist nozzle were conducted using particle image velocimetry (PIV) system and particle motion analysis system (PMAS). The twin-fluid water mist nozzles with swirlers designed two types of swirl angles such as 0 .deg. , 90 .deg. and three different size nozzle hole diameters such as 0.5mm, 1mm, 1.5mm were employed. The experiments were carried out by the injection pressure of water and air divided into 1bar, 2bar respectively. The droplet size of the spray was measured using PMAS. The velocity and turbulence intensity were measured using PIV. The velocity, turbulence intensity and SMD distributions of the sprays were measured along the centerline and radial direction. As the experimental results, swirl angle controlled to droplet sizes. It was found that SMD distribution decreases with the increase of swirl angle. The developed twin-fluid water mist nozzle was satisfied to the criteria of NFPA 750, Class 1. It was proven that the developed nozzle under low pressures could be applied to fire protection system

  19. Magnetogasdynamic Flow Acceleration in a Scramjet Nozzle

    National Research Council Canada - National Science Library

    Harrington, Brian

    2004-01-01

    .... The parameters of conductivity pattern and load factor are varied in both inviscid and viscous flow regimes with the intent of increasing axial force exerted on the flow through a scramjet accelerator...

  20. Consumption, Saving, Investment, and Unemployment. SVAR Tests of the Effects of Changes in the Consumption-Saving Pattern

    OpenAIRE

    Roberto Bande Ramudo; Manuel Fernández Grela; Mª Dolores Riveiro García

    2011-01-01

    In this paper we aim to provide information about the transmission mechanism at work between investment and unemployment by looking at the consumption-saving pattern as a determinant of investment behaviour. Our starting hypothesis is that permanent shifts in the consumption-saving pattern will have permanent effects on investment, with subsequent consequences for the unemployment rate. To test this hypothesis we build an SVAR model for the Spanish economy seeking information about the respon...

  1. Crossmatch testing in kidney transplantation: Patterns of practice and associations with rejection and graft survival

    International Nuclear Information System (INIS)

    Salvalaggio, Paolo R; Graff, Ralph J; Pinsky, Brett; Schnitzler, Mark A; Takemoto, Steven K; Burroughs, Thomas E; Santos, Luiz S; Lentine Krista L

    2009-01-01

    Methods of crossmatch testing prior to kidney transplantation are not standardized and there are limited large-scale data on the use and outcomes implications of crossmatch modality. Data describing the most sensitive crossmatch modality for crossmatch-negative kidney transplants were drawn from the Organ Procurement and Transplant Network Registry. Within the cohort transplanted in 1999-2005, we identified patient and transplant characteristics predictive of each testing modality by multivariate logistic regression. We assessed associations of crossmatch modality with rejection risk by logistic regression and with graft survival by Cox's hazards analysis. Among 230,995 transplants, use of flow cytometry with T-and B-lymphocytes (T and B FC) increased progressively in 1987-2005. Among the recent transplants performed in 1999-2005 (n=64,320), negative T and B FC crossmatch was associated with 15% lower relative risk of first-year acute rejection (adjusted HR 0.85, 95% CI 0.80-0.89) compared to negative T-antihuman-globulin and B-National Institutes of Health/Wash (T AHG and B) crossmatch. Five-year graft survival after transplant with negative T and B FC (82.6%) was modestly better than after negative T AHG and B (81.4%, P0.008) or T AHG crossmatch (81.1%, P 60 years. Many subgroups for whom negative T and B FC crossmatch predicted lower rejection risk (Caucasians, deceased donor recipients, re-transplants) were not more likely to be crossmatched by this method. We conclude that current practice patterns have not aligned utilization of T and B FC crossmatch with associated benefits. Prospective evaluation of the relationship of crossmatch modality with outcomes is warranted. (author)

  2. Patterns of sexual size dimorphism in horseshoe bats: Testing Rensch's rule and potential causes.

    Science.gov (United States)

    Wu, Hui; Jiang, Tinglei; Huang, Xiaobin; Feng, Jiang

    2018-02-08

    Rensch's rule, stating that sexual size dimorphism (SSD) becomes more evident and male-biased with increasing body size, has been well supported for taxa that exhibit male-biased SSD. Bats, primarily having female-biased SSD, have so far been tested for whether SSD allometry conforms to Rensch's rule in only three studies. However, these studies did not consider phylogeny, and thus the mechanisms underlying SSD variations in bats remain unclear. Thus, the present study reviewed published and original data, including body size, baculum size, and habitat types in 45 bats of the family Rhinolophidae to determine whether horseshoe bats follow Rensch's rule using a phylogenetic comparative framework. We also investigated the potential effect of postcopulatory sexual selection and habitat type on SSD. Our findings indicated that Rensch's rule did not apply to Rhinolophidae, suggesting that SSD did not significantly vary with increasing size. This pattern may be attributable interactions between weak sexual selection to male body size and strong fecundity selection for on female body size. The degree of SSD among horseshoe bats may be attributed to a phylogenetic effect rather than to the intersexual competition for food or to baculum length. Interestingly, we observed that species in open habitats exhibited greater SSD than those in dense forests, suggesting that habitat types may be associated with variations in SSD in horseshoe bats.

  3. Computational Simulation on a Coaxial Substream Powder Feeding Laval Nozzle of Cold Spraying

    Directory of Open Access Journals (Sweden)

    Guosheng HUANG

    2014-09-01

    Full Text Available In this paper, a substream coaxial powder feeding nozzle was investigated for use in cold spraying. The relationship between nozzle structure and gas flow, the acceleration behavior of copper particles were examined by computational simulation method. Also, one of the nozzle was used to spray copper coating on steel substrate. The simulation results indicate that: the velocity of gas at the center of the nozzle is lower than that of the conventional nozzle. Powders are well restrained near the central line of the nozzle, no collision occurred between the nozzle wall and the powders. This type of nozzle with expansion 3.25 can successfully deposit copper coating on steel substrate, the copper coating has low porosity about 3.1 % – 3.8 % and high bonding strength about 23.5 MPa – 26.8 MPa. DOI: http://dx.doi.org/10.5755/j01.ms.20.3.4244

  4. Gas flows in radial micro-nozzles with pseudo-shocks

    Science.gov (United States)

    Kiselev, S. P.; Kiselev, V. P.; Zaikovskii, V. N.

    2017-12-01

    In the present paper, results of an experimental and numerical study of supersonic gas flows in radial micro-nozzles are reported. A distinguishing feature of such flows is the fact that two factors, the nozzle divergence and the wall friction force, exert a substantial influence on the flow structure. Under the action of the wall friction force, in the micro-nozzle there forms a pseudo-shock that separates the supersonic from subsonic flow region. The position of the pseudo-shock can be evaluated from the condition of flow blockage in the nozzle exit section. A detailed qualitative and quantitative analysis of gas flows in radial micro-nozzles is given. It is shown that the gas flow in a micro-nozzle is defined by the complicated structure of the boundary layer in the micro-nozzle, this structure being dependent on the width-to-radius ratio of the nozzle and its inlet-to-outlet pressure ratio.

  5. DURACON - Variable Emissivity Broadband Coatings for Liquid Propellant Rocket Nozzles Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The need exists for a fast drying, robust, low gloss, black, high emissivity coating that can be applied easily on aircraft rocket nozzles and nozzle extensions....

  6. Experimental and Numerical Study of Nozzle Plume Impingement on Spacecraft Surfaces

    National Research Council Canada - National Science Library

    Ketsdever, A. D; Lilly, T. C; Gimelshein, S. F; Alexeenko, A. A

    2005-01-01

    ...) nozzle plume impinging on a simulated spacecraft surface. The nozzle flow impingement is investigated experimentally using a nano-Newton resolution force balance and numerically using the Direct Simulation Monte Carlo (DSMC...

  7. Nozzle Plume Impingement on Spacecraft Surfaces: Effects of Surface Roughness (POSTPRINT)

    National Research Council Canada - National Science Library

    Ngalande, C; Killingsworth, M; Lilly, T; Gimelshein, S; Ketsdever, A

    2005-01-01

    ...) nozzle plume impinging on simulated spacecraft surfaces. The nozzle flow impingement is investigated experimentally using a nano-Newton resolution force balance and numerically using the Direct Simulation Monte Carlo (DSMC...

  8. Visualization of Atomization Gas Flow and Melt Break-up Effects in Response to Nozzle Design

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Iver; Rieken, Joel; Meyer, John; Byrd, David; Heidloff, Andy

    2011-04-01

    Both powder particle size control and efficient use of gas flow energy are highly prized goals for gas atomization of metal and alloy powder to minimize off-size powder inventory (or 'reverb') and excessive gas consumption. Recent progress in the design of close-coupled gas atomization nozzles and the water model simulation of melt feed tubes were coupled with previous results from several types of gas flow characterization methods, e.g., aspiration measurements and gas flow visualization, to make progress toward these goals. Size distribution analysis and high speed video recordings of gas atomization reaction synthesis (GARS) experiments on special ferritic stainless steel alloy powders with an Ar+O{sub 2} gas mixture were performed to investigate the operating mechanisms and possible advantages of several melt flow tube modifications with one specific gas atomization nozzle. In this study, close-coupled gas atomization under closed wake gas flow conditions was demonstrated to produce large yields of ultrafine (dia.<20 {mu}m) powders (up to 32%) with moderate standard deviations (1.62 to 1.99). The increased yield of fine powders is consistent with the dual atomization mechanisms of closed wake gas flow patterns in the near-field of the melt orifice. Enhanced size control by stabilized pre-filming of the melt with a slotted trumpet bell pour tube was not clearly demonstrated in the current experiments, perhaps confounded by the influence of the melt oxidation reaction that occurred simultaneously with the atomization process. For this GARS variation of close-coupled gas atomization, it may be best to utilize the straight cylindrical pour tube and closed wake operation of an atomization nozzle with higher gas mass flow to promote the maximum yields of ultrafine powders that are preferred for the oxide dispersion strengthened alloys made from these powders.

  9. Defect Localization Capabilities of a Global Detection Scheme: Spatial Pattern Recognition Using Full-field Vibration Test Data in Plates

    Science.gov (United States)

    Saleeb, A. F.; Prabhu, M.; Arnold, S. M. (Technical Monitor)

    2002-01-01

    Recently, a conceptually simple approach, based on the notion of defect energy in material space has been developed and extensively studied (from the theoretical and computational standpoints). The present study focuses on its evaluation from the viewpoint of damage localization capabilities in case of two-dimensional plates; i.e., spatial pattern recognition on surfaces. To this end, two different experimental modal test results are utilized; i.e., (1) conventional modal testing using (white noise) excitation and accelerometer-type sensors and (2) pattern recognition using Electronic speckle pattern interferometry (ESPI), a full field method capable of analyzing the mechanical vibration of complex structures. Unlike the conventional modal testing technique (using contacting accelerometers), these emerging ESPI technologies operate in a non-contacting mode, can be used even under hazardous conditions with minimal or no presence of noise and can simultaneously provide measurements for both translations and rotations. Results obtained have clearly demonstrated the robustness and versatility of the global NDE scheme developed. The vectorial character of the indices used, which enabled the extraction of distinct patterns for localizing damages proved very useful. In the context of the targeted pattern recognition paradigm, two algorithms were developed for the interrogation of test measurements; i.e., intensity contour maps for the damaged index, and the associated defect energy vector field plots.

  10. Analysis and design of optimized truncated scarfed nozzles subject to external flow effects

    Science.gov (United States)

    Shyne, Rickey J.; Keith, Theo G., Jr.

    1990-01-01

    Rao's method for computing optimum thrust nozzles is modified to study the effects of external flow on the performance of a class of exhaust nozzles. Members of this class are termed scarfed nozzles. These are two-dimensional, nonsymmetric nozzles with a flat lower wall. The lower wall (the cowl) is truncated in order to save weight. Results from a parametric investigation are presented to show the effects of the external flowfield on performance.

  11. Pollution and wet cleaning of separation nozzle systems for enrichment of uranium-235

    International Nuclear Information System (INIS)

    Bacher, W.; Bier, W.; Linder, N.

    1980-06-01

    Operational defects in separation nozzle plants resulting in air leaking into the system may cause permanent pollution of the narrow slits of the separation elements by products of the hydrolysis of UF 6 . The deposits may deteriorate the separation performance of the separation elements to such an extent that their further use for uranium enrichment is no longer feasible. Tests performed on commercial-scale separation element tubes indicated that the deposits can be removed by a wet chemical process effectively enough to restore the full separative power of the elements. The aspects of the technical application of the cleanup process are discussed. (orig.) [de

  12. Theoretical determination of nozzle admittances using a finite element method

    Science.gov (United States)

    Sigman, R. K.; Zinn, B. T.

    1979-01-01

    A finite element method (FEM) is used to predict the admittances of axisymmetric nozzles. The flow in the nozzle is assumed to be isentropic and the disturbances are assumed to be small so that linear analyses apply. An approximate two dimensional compressible flow model is used to describe the steady flow in the nozzle. The propagation of acoustic disturbances is governed by the complete linear acoustic wave equation. This partial differential wave equation is transformed to an integral equation using Galerkin's method and Green's theorem is applied so that the acoustic boundary conditions can be introduced through the boundary residuals. A two dimensional finite element method using linear triangular elements is used to solve the integral acoustic equation. A one dimensional FEM is used to solve the reduced nozzle acoustic equation developed by Crocco and the solution is used to verify the sufficiency of the boundary residual formation. It is shown that agreement between predicted values of the admittance and experimental data is quite good.

  13. SHINE Tritium Nozzle Design: Activity 6, Task 1 Report

    Energy Technology Data Exchange (ETDEWEB)

    Okhuysen, Brett S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pulliam, Elias Noel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-05

    In FY14, we studied the qualitative and quantitative behavior of a SHINE/PNL tritium nozzle under varying operating conditions. The result is an understanding of the nozzle’s performance in terms of important flow features that manifest themselves under different parametric profiles. In FY15, we will consider nozzle design with a focus on nozzle geometry and integration. From FY14 work, we will understand how the SHINE/PNL nozzle behaves under different operating scenarios. The first task for FY15 is to evaluate the FY14 model as a predictor of the actual flow. Considering different geometries is more time-intensive than parameter studies, therefore we recommend considering any relevant flow features that were not included in the FY14 model. In the absence of experimental data, it is particularly important to consider any sources of heat in the domain or boundary conditions that may affect the flow and incorporate these into the simulation if they are significant. Additionally, any geometric features of the beamline segment should be added to the model such as the orifice plate. The FY14 model works with hydrogen. An improvement that can be made for FY15 is to develop CFD properties for tritium and incorporate those properties into the new models.

  14. Numerical analysis of choked converging nozzle flows with surface ...

    Indian Academy of Sciences (India)

    (5a–b). One-dimensional momentum and energy equations (6) and (7) are applied to each differential cell in the nozzle, where the nodal properties such as P,U and Cp are interrelated with the contributions of cellular variants like Ff ,I,dq and . Equation (7) represents the conserva- tion of mechanical and thermal energies ...

  15. Development of rapid mixing fuel nozzle for premixed combustion

    Energy Technology Data Exchange (ETDEWEB)

    Katsuki, Masashi; Chung, Jin Do; Kim, Jang Woo; Hwang, Seung Min [Hoseo University, Asan (Korea, Republic of); Kim, Seung Mo [Pusan National University, Busan (Korea, Republic of); Ahn, Chul Ju [Osaka University, Osaka (Japan)

    2009-03-15

    Combustion in high-preheat and low oxygen concentration atmosphere is one of the attractive measures to reduce nitric oxide emission as well as greenhouse gases from combustion devices, and it is expected to be a key technology for the industrial applications in heating devices and furnaces. Before proceeding to the practical applications, we need to elucidate combustion characteristics of non-premixed and premixed flames in high-preheat and low oxygen concentration conditions from scientific point of view. For the purpose, we have developed a special mixing nozzle to create a homogeneous mixture of fuel and air by rapid mixing, and applied this rapidmixing nozzle to a Bunsen-type burner to observe combustion characteristics of the rapid-mixture. As a result, the combustion of rapid-mixture exhibited the same flame structure and combustion characteristics as the perfectly prepared premixed flame, even though the mixing time of the rapid-mixing nozzle was extremely short as a few milliseconds. Therefore, the rapid-mixing nozzle in this paper can be used to create preheated premixed flames as far as the mixing time is shorter than the ignition delay time of the fuel

  16. Hypersonic Wind Tunnel Nozzle Survivability for T&E

    Science.gov (United States)

    2007-03-01

    used to melt the electrode while a second electron beam was used to control the rate of solidification in the mold . Gas bubbles tend to come to the...38 4.4 Ni -Coated Cu - Back-Side-Cooled Arc-Heater Nozzles .............................................45 5.0 SUMMARY/CONCLUSIONS...25 25. Principal Stress Distribution for Direction 1

  17. Nonlinear indirect combustion noise for compact supercritical nozzle flows

    Science.gov (United States)

    Huet, M.

    2016-07-01

    In this paper, indirect combustion noise generated by the acceleration of entropy perturbations through a supercritical nozzle is investigated in the nonlinear regime and in the low-frequency limit (quasi-static hypothesis). This work completes the study of Huet and Giauque (Journal of Fluid Mechanics 733 (2013) 268-301) for nonlinear noise generation in nozzle flows without shock and particularly focuses on shocked flow regimes. It is based on the analytical model of Marble and Candel for compact nozzles (Journal of Sound and Vibration 55 (1977) 225-243), initially developed for excitations in the linear regime and rederived here for nonlinear perturbations. Full nonlinear analytical solutions are provided in the absence of shock as well as second-order analytical expressions when a shock is present in the diffuser. An analytical evaluation of the shock displacement inside the nozzle caused by the forcing is proposed and maximum possible forcings to avoid unchoke and 'over-choke' are discussed. The accuracy of the second-order model and the nonlinear contributions to the generated waves are then addressed. This model is found to be very accurate for the generated entropy wave with negligible nonlinear contributions. Nonlinearities are more visible, but still limited, for the downstream acoustic wave for large inlet Mach numbers. Analytical developments are validated thanks to comparisons with numerical simulations.

  18. Construction of a pulsed nozzle fourier transform microwave ...

    Indian Academy of Sciences (India)

    Administrator

    Construction of a pulsed nozzle fourier transform microwave spectrometer to study the lithium bond. A P TIWARI 1, B J MUKKADA 1, E ARUNAN 1 and P C MATHIAS 2. 1Department of Inorganic and Physical Chemistry, Indian Institute of. Science, Bangalore 560 012, India. 2Sophisticated Instruments Facility, Indian Institute ...

  19. Ayame/PAM-D apogee kick motor nozzle failure analysis

    Science.gov (United States)

    1981-01-01

    The failure of two communication satellites during firing sequence were examined. The correlation/comparison of the circumstances of the Ayame incidents and the failure of the STAR 48 (DM-2) motor are reviewed. The massive nozzle failure of the AKM to determine the impact on spacecraft performance is examined. It is recommended that a closer watch is kept on systems techniques,

  20. The jet nozzle process for uranium 235 isotopic enrichment

    International Nuclear Information System (INIS)

    Jordan, I.; Umeda, K.; Brown, A.E.P.

    1979-01-01

    A general survey of the isotopic enrichment of Uranium - 235, principally by jet nozzle process, is made. Theoretical treatment of a single stage and cascade of separation stages of the above process with its development in Germany until 1976 is presented [pt

  1. Linking fault pattern with groundwater flow in crystalline rocks at the Grimsel Test Site (Switzerland)

    Science.gov (United States)

    Schneeberger, Raphael; Berger, Alfons; Mäder, Urs K.; Niklaus Waber, H.; Kober, Florian; Herwegh, Marco

    2017-04-01

    Water flow across crystalline bedrock is of major interest for deep-seated geothermal energy projects as well as for underground disposal of radioactive waste. In crystalline rocks enhanced fluid flow is related to zones of increased permeability, i.e. to fractures that are associated to fault zones. The flow regime around the Grimsel Test Site (GTS, Central Aar massif) was assessed by establishing a 3D fault zone pattern on a local scale in the GTS underground facility (deca-meter scale) and on a regional scale at the surface (km-scale). The study reveals the existence of a dense fault zone network consisting of several km long and few tens of cm to meter wide, sub-vertically oriented major faults that are connected by tens to hundreds of meters long minor bridging faults. This geometrical information was used as input for the generation of a 3D fault zone network model. The faults originate from ductile shear zones that were reactivated as brittle faults under retrograde conditions during exhumation. Embrittlement and associated dilatancy along the faults provide the pathways for today's groundwater flow. Detection of the actual 3D flow paths is, however, challenging since flow seem to be not planar but rather tube-like. Two strategies are applied to constrain the 3D geometry of the flow tubes: (i) Characterization of the groundwater infiltrating into the GTS (location, yield, hydraulic head, and chemical composition) and (ii) stress modelling on the base of the 3D structural model to unravel potential domains of enhanced fluid flow such as fault plane intersections and domains of dilatancy. At the Grimsel Test Site, hydraulic and structural data demonstrate that the groundwater flow is head-driven from the surface towards the GTS located some 450 m below the surface. The residence time of the groundwater in this surface-near section is >60 years as evidenced by absence of detectable tritium. However, hydraulic heads obtained from interval pressure measurements

  2. Determination of specificity and pattern of antinuclear antibodies (ana) in systemic rheumatic disease patients positive for ana testing

    International Nuclear Information System (INIS)

    Nawaz, H.; Bashir, M.M.; Iqbal, W.

    2018-01-01

    To determine probability of finding antinuclear antibodies (ANA) and anti extractable nuclear antigens (ENA) positive samples and associating ANA patterns with anti-ENA reactivities among a consecutive cohort of samples of systemic rheumatic disease patients referred for ANA testing. Study Design:Prospective cohort study. Place and Duration of Study:Immunology Department, Armed Forces Institute of Pathology, Rawalpindi, Pakistan, from January to June 2016. Methodology:All the samples referred for ANA testing with clinical suspicion of systemic rheumatic disease were included. After screening, ANA positive samples were subjected to anti-ENA antibodies testing (including anti-SSA, anti-SSB, anti-Sm, anti-RNP, anti-SCL-70 and anti-Jo-1 antibodies) and ANA pattern and titer determination. Results:Of 4,347 samples received, 397 were positive for ANA (9%). Of 397, 96 (24%) samples positive on ENA screen were tested for anti-ENA reactivity. Anti-SSA antibodies were found in 59 samples. Commonest ANA patterns were coarse and fine speckled (43 and 22 samples of 81 tested), while majority of samples carried ANA in titers of 1:40 and 1:80 (22 and 18 samples of 81 tested). No specific ANA pattern was associated with any particular anti-ENA reactivity. Conclusion:Among samples/patients referred for investigations of autoimmune disorders, probability of finding positive ANA is approximately 9%. Of these 9%, about 24% also show reactivity against ENA. Commonest ANA pattern is coarse speckled and majority of such patients carry ANA in titers ranging from 1:40 to 1:80. Commonest ENA reactivity was against SSA. (author)

  3. Patterns of HIV and sexually transmitted infection testing among men who have sex with men couples in the United States.

    Science.gov (United States)

    Mitchell, Jason W; Petroll, Andrew E

    2012-11-01

    Most men who have sex with men (MSM) within the United States acquire human immunodeficiency virus (HIV) while in a same-sex relationship. Few studies have examined HIV and sexually transmitted infection (STI) testing rates among MSM couples. Interestingly, the patterns that MSM test for HIV while in their relationships remain largely unknown. The current study helps fill this gap in knowledge by assessing HIV testing patterns and HIV and STI testing rates from a large convenience sample of Internet-using MSM couples. The current study used a cross-sectional study design to collect dyadic data from 361 MSM couples who lived throughout the United States. A novel recruitment strategy that included placing paid targeted advertisements on Facebook enrolled both men in the couple to independently complete the confidential electronic survey. Nearly half of the HIV-negative men indicated either not having been tested for HIV since their relationship started or only testing if they believed they were at risk. Few men reported testing every 3 to 4 months. HIV/STI testing rates varied among the sample of couples. Few men reported having been diagnosed with a recent STI. Testing patterns and rates were mostly similar, irrespective of whether unprotected anal intercourse was practiced within and/or outside the relationship. HIV testing and prevention services must target men who are at risk for acquiring HIV within MSM couples. To help accomplish this goal, additional research is needed to examine the specific barriers and facilitators to HIV and STI testing among MSM in couples.

  4. Nozzle Printed-PEDOT:PSS for Organic Light Emitting Diodes with Various Dilution Rates of Ethanol

    Directory of Open Access Journals (Sweden)

    Dai Geon Yoon

    2018-01-01

    Full Text Available In this study, we investigated the ink formulation of poly(3,4-ethylenedioxythiophene polystyrene sulfonate (PEDOT:PSS as the hole injection layer (HIL in an organic light emitting diode (OLED structure. Generally, in a PEDOT:PSS solution, water is incorporated in the solution for the solution process. However, the fabrication of thin film which contained the water, main solvent, could not easily form by using printing technology except spin-coating process because of the high surface tension of water. On the other hand, mixing PEDOT:PSS solution and ethanol (EtOH, a dilution solvent, could restrain the non-uniform layer that forms by the high surface tension and low volatility of water. Therefore, we printed a PEDOT:PSS solution with various concentrations of EtOH by using a nozzle printer and obtained a uniform pattern. The line width of PEDOT:PSS diluted with 90% (volume ratio ehtanol was measured as about 4 mm with good uniformity with a 0.1 mm nozzle. Also, imaging software and a scanning electron microscope (SEM were used to measure the uniformity of PEDOT:PSS coated on a substrate. Finally, we fabricated a green phosphorescent OLED device with printed-PEDOT:PSS with specific concentrations of EtOH and we achieved a current efficiency of 27 cd/A with uniform quality of luminance in the case of device containing 90% EtOH.

  5. [Effect of Music Intervention on Maternal Anxiety and Fetal Heart Rate Pattern During Non-Stress Test].

    Science.gov (United States)

    Oh, Myung Ok; Kim, Young Jeoum; Baek, Cho Hee; Kim, Ju Hee; Park, No Mi; Yu, Mi Jeong; Song, Han Sol

    2016-06-01

    The purpose of this cross-over experimental study was to examine effects of music intervention on maternal anxiety, fetal heart rate pattern and testing time during non-stress tests (NST) for antenatal fetal assessment. Sixty pregnant women within 28 to 40 gestational weeks were randomly assigned to either the experimental group (n=30) or control group (n=30). Music intervention was provided to pregnant women in the experimental group during NST. Degree of maternal anxiety and fetal heart rate pattern were our primary outcomes. State-trait anxiety inventory, blood pressure, pulse rate, and changes in peripheral skin temperature were assessed to determine the degree of maternal anxiety. Baseline fetal heart rate, frequency of acceleration in fetal heart rate, fetal movement test and testing time for reactive NST were assessed to measure the fetal heart rate pattern. The experimental group showed significantly lower scores in state anxiety than the control group. There were no significant differences in systolic blood pressure and pulse rate between the two groups. Baseline fetal heart rate was significantly lower in the experimental group than in the control group. Frequency of acceleration in fetal heart rate was significantly increased in the experimental group compared to the control group. There were no significant differences in fetal movement and testing time for reactive NST between the two groups. Present results suggest that music intervention could be an effective nursing intervention for alel viating anxiety during non-stress test.

  6. System and method having multi-tube fuel nozzle with differential flow

    Science.gov (United States)

    Hughes, Michael John; Johnson, Thomas Edward; Berry, Jonathan Dwight; York, William David

    2017-01-03

    A system includes a multi-tube fuel nozzle with a fuel nozzle body and a plurality of tubes. The fuel nozzle body includes a nozzle wall surrounding a chamber. The plurality of tubes extend through the chamber, wherein each tube of the plurality of tubes includes an air intake portion, a fuel intake portion, and an air-fuel mixture outlet portion. The multi-tube fuel nozzle also includes a differential configuration of the air intake portions among the plurality of tubes.

  7. Turbine combustor with fuel nozzles having inner and outer fuel circuits

    Science.gov (United States)

    Uhm, Jong Ho; Johnson, Thomas Edward; Kim, Kwanwoo

    2013-12-24

    A combustor cap assembly for a turbine engine includes a combustor cap and a plurality of fuel nozzles mounted on the combustor cap. One or more of the fuel nozzles would include two separate fuel circuits which are individually controllable. The combustor cap assembly would be controlled so that individual fuel circuits of the fuel nozzles are operated or deliberately shut off to provide for physical separation between the flow of fuel delivered by adjacent fuel nozzles and/or so that adjacent fuel nozzles operate at different pressure differentials. Operating a combustor cap assembly in this fashion helps to reduce or eliminate the generation of undesirable and potentially harmful noise.

  8. A380 pavement experimental program-rigid campaign : slab pattern, instrumentation, static test procedure, fatigue test introduction

    OpenAIRE

    LERAT, P; FABRE, C; BALAY, JM

    2003-01-01

    The paper describes several experimentations on rigid pavements at Toulouse Blagnac airport, tested with heavy aircraft landing gear simulator developed by Airbus S.A.S. The main contributors of this program are Airbus, the French Civil Aviation Administration (STBA) and the French Road and Bridges Laboratory (LCPC). The first part of the program (1998 2000) deals with bituminous pavement. In 2001-2002-2003 the program has focused on Rigid tests. The main aim has been therefore to improve th...

  9. The effects of a spray slurry nozzle on copper CMP for reduction in slurry consumption

    International Nuclear Information System (INIS)

    Lee, Da Sol; Jeong, Hae Do; Lee, Hyun Seop

    2015-01-01

    The environmental impact of semiconductor manufacturing has been a big social problem, like greenhouse gas emission. Chemical mechanical planarization (CMP), a wet process which consumes chemical slurries, seriously impacts environmental sustain ability and cost-effectiveness. This paper demonstrates the superiority of a full-cone spray slurry nozzle to the conventional tube-type slurry nozzle in Cu CMP. It was observed that the spray nozzle made a weak slurry wave at the retaining ring unlike a conventional nozzle, because the slurry was supplied uniformly in broader areas. Experiments were implemented with different slurry flow rates and spray nozzle heights. Spray nozzle performance is controlled by the spray angle and spray height. The process temperature was obtained with an infrared (IR) sensor and an IR thermal imaging camera to investigate the cooling effect of the spray. The results show that the spray nozzle provides a higher Material removal rate (MRR), lower non-uniformity (NU), and lower temperature than the conventional nozzle. Computational fluid dynamics techniques show that the turbulence kinetic energy and slurry velocity of the spray nozzle are much higher than those of the conventional nozzle. Finally, it can be summarized that the spray nozzle plays a significant role in slurry efficiency by theory of Minimum quantity lubrication (MQL).

  10. The proton therapy nozzles at Samsung Medical Center: A Monte Carlo simulation study using TOPAS

    Science.gov (United States)

    Chung, Kwangzoo; Kim, Jinsung; Kim, Dae-Hyun; Ahn, Sunghwan; Han, Youngyih

    2015-07-01

    To expedite the commissioning process of the proton therapy system at Samsung Medical Center (SMC), we have developed a Monte Carlo simulation model of the proton therapy nozzles by using TOol for PArticle Simulation (TOPAS). At SMC proton therapy center, we have two gantry rooms with different types of nozzles: a multi-purpose nozzle and a dedicated scanning nozzle. Each nozzle has been modeled in detail following the geometry information provided by the manufacturer, Sumitomo Heavy Industries, Ltd. For this purpose, the novel features of TOPAS, such as the time feature or the ridge filter class, have been used, and the appropriate physics models for proton nozzle simulation have been defined. Dosimetric properties, like percent depth dose curve, spreadout Bragg peak (SOBP), and beam spot size, have been simulated and verified against measured beam data. Beyond the Monte Carlo nozzle modeling, we have developed an interface between TOPAS and the treatment planning system (TPS), RayStation. An exported radiotherapy (RT) plan from the TPS is interpreted by using an interface and is then translated into the TOPAS input text. The developed Monte Carlo nozzle model can be used to estimate the non-beam performance, such as the neutron background, of the nozzles. Furthermore, the nozzle model can be used to study the mechanical optimization of the design of the nozzle.

  11. The effects of a spray slurry nozzle on copper CMP for reduction in slurry consumption

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Da Sol; Jeong, Hae Do [Pusan National University, Busan (Korea, Republic of); Lee, Hyun Seop [Tongmyong University, Busan (Korea, Republic of)

    2015-12-15

    The environmental impact of semiconductor manufacturing has been a big social problem, like greenhouse gas emission. Chemical mechanical planarization (CMP), a wet process which consumes chemical slurries, seriously impacts environmental sustain ability and cost-effectiveness. This paper demonstrates the superiority of a full-cone spray slurry nozzle to the conventional tube-type slurry nozzle in Cu CMP. It was observed that the spray nozzle made a weak slurry wave at the retaining ring unlike a conventional nozzle, because the slurry was supplied uniformly in broader areas. Experiments were implemented with different slurry flow rates and spray nozzle heights. Spray nozzle performance is controlled by the spray angle and spray height. The process temperature was obtained with an infrared (IR) sensor and an IR thermal imaging camera to investigate the cooling effect of the spray. The results show that the spray nozzle provides a higher Material removal rate (MRR), lower non-uniformity (NU), and lower temperature than the conventional nozzle. Computational fluid dynamics techniques show that the turbulence kinetic energy and slurry velocity of the spray nozzle are much higher than those of the conventional nozzle. Finally, it can be summarized that the spray nozzle plays a significant role in slurry efficiency by theory of Minimum quantity lubrication (MQL).

  12. Patterns of HIV testing practices among young gay and bisexual men living in Scotland: a qualitative study

    Directory of Open Access Journals (Sweden)

    Nicola Boydell

    2017-08-01

    Full Text Available Abstract Background Increasing overall rates, and frequency, of HIV testing in populations at risk is a key public health objective and a critical dimension of HIV prevention efforts. In the UK, men who have sex with men (MSM remain one of the communities most at risk of HIV and, within this, young gay men are a key risk group. Understanding HIV testing practices is important in the development of interventions to promote testing among young gay and bisexual men. Methods Qualitative interviews were conducted with thirty young gay and bisexual men (aged 18–29 in Scotland. Thematic analysis of men’s accounts of their approach to HIV testing identified three overarching patterns of testing: ‘habitual’, ‘reactive’ and ‘ ad hoc’. Results This qualitative study, the first to explore patterns of HIV testing practices among young gay and bisexual men in the UK, contributes novel findings around the role of social support and ‘community’ in shaping young men’s approaches to HIV testing. The findings suggest that social support can play an important role in encouraging and facilitating HIV testing among young gay men, however, social norms of non-testing also have the potential to act as a barrier to development of a regular routine. Men with habitual testing practices framed HIV testing as both a personal and ‘community’ responsibility, and more effective than testing in response to risk events or emergent symptoms. Men who reported reactive testing practices described testing for HIV primarily in response to perceived exposure to sexual risk, along with ‘transitional moments’ such as starting, ending or changes to a relationship. Among young men who reported testing on an ad hoc basis, inconvenience and disruptions to HIV testing practices, particularly where men lacked social support, acted as a barrier to developing a routine of regular testing. Conclusions Our findings suggest that interventions which seek to increase

  13. Patterns of HIV testing practices among young gay and bisexual men living in Scotland: a qualitative study.

    Science.gov (United States)

    Boydell, Nicola; Buston, Katie; McDaid, Lisa Margaret

    2017-08-17

    Increasing overall rates, and frequency, of HIV testing in populations at risk is a key public health objective and a critical dimension of HIV prevention efforts. In the UK, men who have sex with men (MSM) remain one of the communities most at risk of HIV and, within this, young gay men are a key risk group. Understanding HIV testing practices is important in the development of interventions to promote testing among young gay and bisexual men. Qualitative interviews were conducted with thirty young gay and bisexual men (aged 18-29) in Scotland. Thematic analysis of men's accounts of their approach to HIV testing identified three overarching patterns of testing: 'habitual', 'reactive' and ' ad hoc'. This qualitative study, the first to explore patterns of HIV testing practices among young gay and bisexual men in the UK, contributes novel findings around the role of social support and 'community' in shaping young men's approaches to HIV testing. The findings suggest that social support can play an important role in encouraging and facilitating HIV testing among young gay men, however, social norms of non-testing also have the potential to act as a barrier to development of a regular routine. Men with habitual testing practices framed HIV testing as both a personal and 'community' responsibility, and more effective than testing in response to risk events or emergent symptoms. Men who reported reactive testing practices described testing for HIV primarily in response to perceived exposure to sexual risk, along with 'transitional moments' such as starting, ending or changes to a relationship. Among young men who reported testing on an ad hoc basis, inconvenience and disruptions to HIV testing practices, particularly where men lacked social support, acted as a barrier to developing a routine of regular testing. Our findings suggest that interventions which seek to increase rates of HIV testing and testing frequency among young gay and bisexual men should include a

  14. SINGLE PHASE ANALYTICAL MODELS FOR TERRY TURBINE NOZZLE

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Haihua; Zhang, Hongbin; Zou, Ling; O' Brien, James

    2016-11-01

    All BWR RCIC (Reactor Core Isolation Cooling) systems and PWR AFW (Auxiliary Feed Water) systems use Terry turbine, which is composed of the wheel with turbine buckets and several groups of fixed nozzles and reversing chambers inside the turbine casing. The inlet steam is accelerated through the turbine nozzle and impacts on the wheel buckets, generating work to drive the RCIC pump. As part of the efforts to understand the unexpected “self-regulating” mode of the RCIC systems in Fukushima accidents and extend BWR RCIC and PWR AFW operational range and flexibility, mechanistic models for the Terry turbine, based on Sandia National Laboratories’ original work, has been developed and implemented in the RELAP-7 code to simulate the RCIC system. RELAP-7 is a new reactor system code currently under development with the funding support from U.S. Department of Energy. The RELAP-7 code is a fully implicit code and the preconditioned Jacobian-free Newton-Krylov (JFNK) method is used to solve the discretized nonlinear system. This paper presents a set of analytical models for simulating the flow through the Terry turbine nozzles when inlet fluid is pure steam. The implementation of the models into RELAP-7 will be briefly discussed. In the Sandia model, the turbine bucket inlet velocity is provided according to a reduced-order model, which was obtained from a large number of CFD simulations. In this work, we propose an alternative method, using an under-expanded jet model to obtain the velocity and thermodynamic conditions for the turbine bucket inlet. The models include both adiabatic expansion process inside the nozzle and free expansion process out of the nozzle to reach the ambient pressure. The combined models are able to predict the steam mass flow rate and supersonic velocity to the Terry turbine bucket entrance, which are the necessary input conditions for the Terry Turbine rotor model. The nozzle analytical models were validated with experimental data and

  15. Low-drift nozzles vs. standard nozzles for pesticide application in the biological efficacy trials of pesticides in apple pest and disease control.

    Science.gov (United States)

    Doruchowski, Grzegorz; Świechowski, Waldemar; Masny, Sylwester; Maciesiak, Alicja; Tartanus, Małgorzata; Bryk, Hanna; Hołownicki, Ryszard

    2017-01-01

    The coarse spray air-induction nozzles have documented pesticide drift reducing potential and hence pose lower risk of environmental pollution than the standard fine spray hollow cone nozzles. However, it is questioned that use of the low-drift nozzles might not provide as effective crop protection as the standard nozzles. The objective of work was to assess the pest and disease control efficacy as affected by spray volume rate and nozzle type. The experiment was carried out in apple orchard, cv Jonagold/M26. The evaluated treatments were combinations of three spray volume rates: 250, 500 and 750lha -1 , and two types of nozzles: hollow cone nozzles generating very fine spray, and flat fan air induction nozzles producing coarse droplets. The biological performance of treatments was determined based on severity of diseases: apple scab (Venturia inaequalis), powdery mildew (Podosphaera leucotricha) and bull's eye rot (Pezicula spp.), as well as population or damage caused by pests: green apple aphid (Aphis pomi), rosy apple aphid (Dysaphis plantaginea Pass.), woolly apple aphid (Eriosoma lanigerum), apple rust mite (Aculus schlechtendali) and apple blossom weevil (Anthonomus pomorum L.). In general apple scab was equally controlled by all treatments. Only in the years of high infection pressure efficacy of powdery mildew control was better for fine spray nozzles and high volume rates. Green and rosy apple aphids were better controlled with higher volume rates, though significance of the advantage over the lower rates was occasional. No effect of spray quality on efficacy of aphid and mite control was found for any spray volume rate. Better control of apple blossom weevil and woolly apple aphid was achieved with the high spray volume rate providing heavy coverage to the point of run-off. The air induction nozzles having drift reducing potential are biologically efficacious alternative to conventional hollow cone nozzles. Copyright © 2016 Elsevier B.V. All rights

  16. Relations between the discharge coefficients of the sonic venturi nozzle and a kind of gases; Onsoku nozzle no ryushutsu keisu to gas shu tono kankei

    Energy Technology Data Exchange (ETDEWEB)

    Nakao, S.; Takamoto, M. [National Research Laboratory of Metrology, Tsukuba (Japan); Hirayama, T.

    2000-02-25

    The discharge coefficients of the sonic Venturi nozzle were measured for eleven gases on the Reynolds number range from 2 x 10{sup 3} to 4 x 10{sup 4}. The results showed that the discharge coefficients strongly depend on gases. And it was also suggested that the discharge coefficients of most of the gases tested can be described by using two parameters theoretically determined on the assumption of isentropic flow of ideal gas, if they are on the conditions which are not so far from the ideal gas state. The differences between the theoretical and the experimental discharge coefficients were within 0.5 percent, except for CO{sub 2}, SF{sub 6} and C{sub 3}H{sub 8}. (author)

  17. Test results for round-hole-pattern damper seals - Optimum configurations and dimensions for maximum net damping

    Science.gov (United States)

    Childs, D. W.; Kim, C.-H.

    1985-01-01

    Test results are presented for nine annular seals which use a roughened stator and smooth rotor to yield an increase in net damping as compared to conventional smooth-rotor/smooth-stator annular seals. Round-hole roughness patterns are used to achieve the desired stator roughness. The results presented demonstrate that the maximum net damping is achieved by (a) a hole pattern which takes up about 34 percent of the surface area, and (b) hole depths which are about three times the radial clearances. When compared to a smooth seal, the optimum configuration increases net damping by 37 percent, while reducing leakage by 46 percent and direct stiffness by 23 percent. Comparisons of experiment to theory are generally satisfactory for hole-patterns near the optimum area ratio of 34 percent. However, the theory is unsatisfactory for seals which have a substantially higher percentage of the surface area taken up by holes.

  18. Testing key predictions of the associative account of mirror neurons in humans using multivariate pattern analysis

    NARCIS (Netherlands)

    Oosterhof, N.N.; Wiggett, AJ.; Cross, E.S.

    2014-01-01

    Cook et al. overstate the evidence supporting their associative account of mirror neurons in humans: most studies do not address a key property, action-specificity that generalizes across the visual and motor domains. Multivariate pattern analysis (MVPA) of neuroimaging data can address this

  19. Testing an Online Spread Pattern Determination Sensor on a Broadcast Fertilizer Spreader

    NARCIS (Netherlands)

    Grift, T.E.; Hofstee, J.W.

    2002-01-01

    An alternative method for fertilizer spread pattern determination was developed based on predicting where individual fertilizer particles land on the ground, in contrast to the traditional method of collecting the particles in bins (ASAE Standard S341.2). A small broadcast granular fertilizer

  20. Comparison of tests for spatial heterogeneity on data with global clustering patterns and outliers

    Directory of Open Access Journals (Sweden)

    Hachey Mark

    2009-10-01

    Full Text Available Abstract Background The ability to evaluate geographic heterogeneity of cancer incidence and mortality is important in cancer surveillance. Many statistical methods for evaluating global clustering and local cluster patterns are developed and have been examined by many simulation studies. However, the performance of these methods on two extreme cases (global clustering evaluation and local anomaly (outlier detection has not been thoroughly investigated. Methods We compare methods for global clustering evaluation including Tango's Index, Moran's I, and Oden's I*pop; and cluster detection methods such as local Moran's I and SaTScan elliptic version on simulated count data that mimic global clustering patterns and outliers for cancer cases in the continental United States. We examine the power and precision of the selected methods in the purely spatial analysis. We illustrate Tango's MEET and SaTScan elliptic version on a 1987-2004 HIV and a 1950-1969 lung cancer mortality data in the United States. Results For simulated data with outlier patterns, Tango's MEET, Moran's I and I*pop had powers less than 0.2, and SaTScan had powers around 0.97. For simulated data with global clustering patterns, Tango's MEET and I*pop (with 50% of total population as the maximum search window had powers close to 1. SaTScan had powers around 0.7-0.8 and Moran's I has powers around 0.2-0.3. In the real data example, Tango's MEET indicated the existence of global clustering patterns in both the HIV and lung cancer mortality data. SaTScan found a large cluster for HIV mortality rates, which is consistent with the finding from Tango's MEET. SaTScan also found clusters and outliers in the lung cancer mortality data. Conclusion SaTScan elliptic version is more efficient for outlier detection compared with the other methods evaluated in this article. Tango's MEET and Oden's I*pop perform best in global clustering scenarios among the selected methods. The use of SaTScan for

  1. A ceramic nozzle for the NASA-Langley 2.4-m /8.0-ft/ high temperature structures tunnel

    Science.gov (United States)

    Buckley, J. D.; Vasquez, P.

    1982-01-01

    Two materials, a refractory castable ceramic and a SiO2-SiO2 composite, were fabricated as nozzle inserts for the Langley Research Center's 2.4-m (8.0-ft) high temperature structures tunnel. The high pressure and intense heat of the CH4-air products of the combustion-gas stream limits the materials that can be used in this tunnel. The castable-ceramic material showed good resistance to erosion and the thermal loads imposed on it by the gas stream but failed in tension when subjected to high hoop stresses. The SiO2-SiO2-composite nozzle insert withstood the thermomechanical loads but eroded unacceptably with increasing test temperature and pressure.

  2. MISMATCH: A basis for semi-automatic functional mixed-signal test-pattern generation

    NARCIS (Netherlands)

    Kerkhoff, Hans G.; Tangelder, R.J.W.T.; Speek, Han; Engin, N.

    1996-01-01

    This paper describes a tool which assists the designer in the rapid generation of functional tests for mixed-signal circuits down to the actual test-signals for the tester. The tool is based on manipulating design data, making use of macro-based test libraries and tester resources provided by the

  3. Cooling nozzles characteristics for numerical models of continuous casting

    Directory of Open Access Journals (Sweden)

    R. Pyszko

    2013-10-01

    Full Text Available Modelling the temperature field of a continuously cast strand is an important tool for the process diagnostics. The main preconditions for numerical simulation of the temperature field of the solidifying strand are correct boundary conditions, especially the surface condition in the secondary zone of the caster. The paper deals with techniques of determining the surface condition under cooling nozzles as well as their approximation and implementation into the model algorithm. Techniques used for laboratory measurements of both cold and hot spraying characteristics of water or water-air cooling nozzles are described. The relationship between the cold and hot characteristics was found. Implementation of such a dependence into the model algorithm reduces the duration and cost of laboratory measurements.

  4. Low NOx nozzle tip for a pulverized solid fuel furnace

    Science.gov (United States)

    Donais, Richard E; Hellewell, Todd D; Lewis, Robert D; Richards, Galen H; Towle, David P

    2014-04-22

    A nozzle tip [100] for a pulverized solid fuel pipe nozzle [200] of a pulverized solid fuel-fired furnace includes: a primary air shroud [120] having an inlet [102] and an outlet [104], wherein the inlet [102] receives a fuel flow [230]; and a flow splitter [180] disposed within the primary air shroud [120], wherein the flow splitter disperses particles in the fuel flow [230] to the outlet [104] to provide a fuel flow jet which reduces NOx in the pulverized solid fuel-fired furnace. In alternative embodiments, the flow splitter [180] may be wedge shaped and extend partially or entirely across the outlet [104]. In another alternative embodiment, flow splitter [180] may be moved forward toward the inlet [102] to create a recessed design.

  5. Bundled multi-tube nozzle for a turbomachine

    Science.gov (United States)

    Lacy, Benjamin Paul; Ziminsky, Willy Steve; Johnson, Thomas Edward; Zuo, Baifang; York, William David; Uhm, Jong Ho

    2015-09-22

    A turbomachine includes a compressor, a combustor operatively connected to the compressor, an end cover mounted to the combustor, and an injection nozzle assembly operatively connected to the combustor. The injection nozzle assembly includes a cap member having a first surface that extends to a second surface. The cap member further includes a plurality of openings. A plurality of bundled mini-tube assemblies are detachably mounted in the plurality of openings in the cap member. Each of the plurality of bundled mini-tube assemblies includes a main body section having a first end section and a second end section. A fluid plenum is arranged within the main body section. A plurality of tubes extend between the first and second end sections. Each of the plurality of tubes is fluidly connected to the fluid plenum.

  6. Apparatus and method for a gas turbine nozzle

    Science.gov (United States)

    Zuo, Baifang; Ziminsky, Willy Steve; Johnson, Thomas Edward; Intile, John Charles; Lacy, Benjamin Paul

    2013-02-05

    A nozzle includes an inlet, an outlet, and an axial centerline. A shroud surrounding the axial centerline extends from the inlet to the outlet and defines a circumference. The circumference proximate the inlet is greater than the circumference at a first point downstream of the inlet, and the circumference at the first point downstream of the inlet is less than the circumference at a second point downstream of the first point. A method for supplying a fuel through a nozzle directs a first airflow along a first path and a second airflow along a second path separate from the first path. The method further includes injecting the fuel into at least one of the first path or the second path and accelerating at least one of the first airflow or the second airflow.

  7. Development of Submerged Entry Nozzles that Resist Clogging

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Jeffrey D. Smith; Kent D. Peasle

    2002-10-14

    Accretion formation and the associated clogging of SENs is a major problem for the steel industry leading to decreased strand speed, premature changing of SENs or strand termination and the associated reductions in productivity, consistency, and steel quality. A program to evaluate potentially clog resistance materials was initiated at the University of Missouri-Rolla. The main objective of the research effort was to identify combinations of steelmaking and refractory practices that would yield improved accretion resistance for tundish nozzles and submerged entry nozzles. A number of tasks were identified during the initial kick-off meeting and each was completed with two exceptions, the thermal shock validation and the industrial trials. Not completing these two tasks related to not having access to industrial scale production facilities. Though much of the results and information generated in the project is of proprietary nature.

  8. Learning and error patterns in the Chinese Verbal Learning Test in subjects with mild cognitive impairment and normal elderly.

    Science.gov (United States)

    Chen, Nai-Ching; Lin, Yu-Ing; Chang, Chiung-Chih; Lin, Ker-Neng; Chuang, Yao-Chung; Chen, Ching; Tu, Ming-Chien; Wang, Pei-Ning

    2011-06-01

    The discrimination between normal elderly (NC) and those with mild cognitive impairment (MCI) is of clinical relevance since the conversion from MCI to Alzheimer dementia (AD) is high. This study enrolled 216 amnestic MCI patients and 103 NC from our memory clinics and assessed whether the learning curve, recall and cued scores, as well as error patterns from the Chinese Version Verbal Learning Test (CVVLT) helped to distinguish between these two groups. Our results revealed that subjects with MCI had a lower rate of acquisition and deceleration of learning in the learning curve. The MCI group also showed a lower retention rate and recall scores as compared with the NC group. Further, the error patterns offered discrimination values between the two groups in total number of perseverations, intrusion in the cued recall, as well as prototypic and unrelated errors in recognition. An inverse correlation was seen between memory scores and error patterns. This study suggests that by combining the learning and error patterns from the verbal memory test, patients with MCI can be better differentiated from normal elderly.

  9. Magnetic Nozzles for Plasma Thrusters: Acceleration, Thrust, and Detachment Mechanisms

    Science.gov (United States)

    2011-10-01

    experience a large acceleration, and due to its curved shape, ions near the outer border are accelerated first, and acquire a strong radial component. This... border . Induced eld does not acceler- ate demagnetization here, but it can still occur naturally further downstream, as the nozzle opens and B decreases...parametric regimes of the plasma response. Interestingly, the colli - sionless electron skin-depth, generally related to time-dependent problems, such as

  10. Simulation of a shock tube with a small exit nozzle

    Science.gov (United States)

    Luan, Yigang; Olzmann, Matthias; Magagnato, Franco

    2018-02-01

    Shock tubes are frequently used to rapidly heat up reaction mixtures to study chemical reaction mechanisms and kinetics in the field of combustion chemistry [1]. In the present work, the flow field inside a shock tube with a small nozzle in the end plate has been investigated to support the analysis of reacting chemical mixtures with an attached mass spectrometer and to clarify whether the usual assumptions for the flow field and the related thermodynamics are fulfilled. In the present work, the details of the flow physics inside the tube and the flow out of the nozzle in the end plate have been investigated. Due to the large differences in the typical length scales and the large pressure ratios of this special device, a very strong numerical stiffness prevails during the simulation process. Second-order ROE numerical schemes have been employed to simulate the flow field inside the shock tube. The simulations were performed with the commercial code ANSYS Fluent [2]. Axial-symmetric boundary conditions are employed to reduce the consumption of CPU time. A density-based transient scheme has been used and validated in terms of accuracy and efficiency. The simulation results for pressure and density are compared with analytical solutions. Numerical results show that a density-based numerical scheme performs better when dealing with shock-tube problems [5]. The flow field near the nozzle is studied in detail, and the effects of the nozzle to pressure and temperature variations inside the tube are investigated. The results show that this special shock-tube setup can be used to study high-temperature gas-phase chemical reactions with reasonable accuracy.

  11. Effective hydraulic resistance of actuator nozzle generating a periodic jet

    Czech Academy of Sciences Publication Activity Database

    Tesař, Václav

    2012-01-01

    Roč. 179, JUN 2012 (2012), s. 211-222 ISSN 0924-4247 R&D Projects: GA ČR(CZ) GCP101/11/J019; GA TA ČR(CZ) TA02020795 Institutional research plan: CEZ:AV0Z20760514 Keywords : nozzle * periodic flow * compressibility Subject RIV: BK - Fluid Dynamics Impact factor: 1.841, year: 2012 http://www.sciencedirect.com/science/article/pii/S0924424712001781

  12. Operating a magnetic nozzle helicon thruster with strong magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Kazunori, E-mail: kazunori@ecei.tohoku.ac.jp; Komuro, Atsushi; Ando, Akira [Department of Electrical Engineering, Tohoku University, Sendai 980-8579 (Japan)

    2016-03-15

    A pulsed axial magnetic field up to ∼2.8 kG is applied to a 26-mm-inner-diameter helicon plasma thruster immersed in a vacuum chamber, and the thrust is measured using a pendulum target. The pendulum is located 30-cm-downstream of the thruster, and the thruster rf power and argon flow rate are fixed at 1 kW and 70 sccm (which gives a chamber pressure of 0.7 mTorr). The imparted thrust increases as the applied magnetic field is increased and saturates at a maximum value of ∼9.5 mN for magnetic field above ∼2 kG. At the maximum magnetic field, it is demonstrated that the normalized plasma density, and the ion flow energy in the magnetic nozzle, agree within ∼50% and of 10%, respectively, with a one-dimensional model that ignores radial losses from the nozzle. This magnetic nozzle model is combined with a simple global model of the thruster source that incorporates an artificially controlled factor α, to account for radial plasma losses to the walls, where α = 0 and 1 correspond to zero losses and no magnetic field, respectively. Comparison between the experiments and the model implies that the radial losses in the thruster source are experimentally reduced by the applied magnetic field to about 10% of that obtained from the no magnetic field model.

  13. Nozzle Flow with Vibrational Nonequilibrium. Ph.D. Thesis

    Science.gov (United States)

    Landry, John Gary

    1995-01-01

    Flow of nitrogen gas through a converging-diverging nozzle is simulated. The flow is modeled using the Navier-Stokes equations that have been modified for vibrational nonequilibrium. The energy equation is replaced by two equations. One equation accounts for energy effects due to the translational and rotational degrees of freedom, and the other accounts for the affects due to the vibrational degree of freedom. The energy equations are coupled by a relaxation time which measures the time required for the vibrational energy component to equilibrate with the translational and rotational energy components. An improved relaxation time is used in this thesis. The equations are solved numerically using the Steger-Warming flux vector splitting method and the Implicit MacCormack method. The results show that uniform flow is produced outside of the boundary layer. Nonequilibrium exists in both the converging and diverging nozzle sections. The boundary layer region is characterized by a marked increase in translational-rotational temperature. The vibrational temperature remains frozen downstream of the nozzle, except in the boundary layer.

  14. Chemical processes in the turbine and exhaust nozzle

    Energy Technology Data Exchange (ETDEWEB)

    Lukachko, S.P.; Waitz, I.A. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Aero-Environmental Lab.; Miake-Lye, R.C.; Brown, R.C.; Anderson, M.R. [Aerodyne Research, Inc., Billerica, MA (United States); Dawes, W.N. [University Engineering Dept., Cambridge (United Kingdom). Whittle Lab.

    1997-12-31

    The objective is to establish an understanding of primary pollutant, trace species, and aerosol chemical evolution as engine exhaust travels through the nonuniform, unsteady flow fields of the turbine and exhaust nozzle. An understanding of such processes is necessary to provide accurate inputs for plume-wake modeling efforts and is therefore a critical element in an assessment of the atmospheric effects of both current and future aircraft. To perform these studies, a numerical tool was developed combining the calculation of chemical kinetics and one-, two-, or three-dimensional (1-D, 2-D, 3-D) Reynolds-averaged flow equations. Using a chemistry model that includes HO{sub x}, NO{sub y}, SO{sub x}, and CO{sub x} reactions, several 1-D parametric analyses were conducted for the entire turbine and exhaust nozzle flow path of a typical advanced subsonic engine to understand the effects of various flow and chemistry uncertainties on a baseline 1-D result. These calculations were also used to determine parametric criteria for judging 1-D, 2-D, and 3-D modeling requirements as well as to provide information about chemical speciation at the nozzle exit plane. (author) 9 refs.

  15. Development of Thermal Barriers For Solid Rocket Motor Nozzle Joints

    Science.gov (United States)

    Steinetz, Bruce M.; Dunlap, Patrick H., Jr.

    2000-01-01

    Joints in the Space Shuttle solid rocket motors are sealed by O-rings to contain combustion gases inside the rocket that reach pressures of up to 900 psi and temperatures of up to 5500 F. To provide protection for the O-rings, the motors are insulated with either phenolic or rubber insulation. Gaps in the joints leading up to the O-rings are filled with polysulfide joint-fill compounds as an additional level of protection. The current RSRM nozzle-to-case joint design incorporating primary, secondary, and wiper O-rings experiences gas paths through the joint-fill compound to the innermost wiper O-ring in about one out of every seven motors. Although this does not pose a safety hazard to the motor, it is an undesirable condition that NASA and rocket manufacturer Thiokol want to eliminate. Each nozzle-to-case joint gas path results in extensive reviews and evaluation before flights can be resumed. Thiokol and NASA Marshall are currently working to improve the nozzle-to-case joint design by implementing a more reliable J-leg design that has been used successfully in the field and igniter joint. They are also planning to incorporate the NASA Glenn braided carbon fiber thermal barrier into the joint. The thermal barrier would act as an additional level of protection for the O-rings and allow the elimination of the joint-fill compound from the joint.

  16. Thrust Augmentation by Airframe-Integrated Linear-Spike Nozzle Concept for High-Speed Aircraft

    Directory of Open Access Journals (Sweden)

    Hidemi Takahashi

    2018-02-01

    Full Text Available The airframe-integrated linear-spike nozzle concept applied to an external nozzle for high-speed aircraft was evaluated with regard to the thrust augmentation capability and the trim balance. The main focus was on the vehicle aftbody. The baseline airframe geometry was first premised to be a hypersonic waverider design. The baseline aftbody case had an external nozzle comprised of a simple divergent nozzle and was hypothetically replaced with linear-spike external nozzle configurations. Performance evaluation was mainly conducted by considering the nozzle thrust generated by the pressure distribution on the external nozzle surface at the aftbody portion calculated by computer simulation at a given cruise condition with zero angle of attack. The thrust performance showed that the proposed linear-spike external nozzle concept was beneficial in thrust enhancement compared to the baseline geometry because the design of the proposed concept had a compression wall for the exhaust flow, which resulted in increasing the wall pressure. The configuration with the boattail and the angled inner nozzle exhibited further improvement in thrust performance. The trim balance evaluation showed that the aerodynamic center location appeared as acceptable. Thus, benefits were obtained by employing the airframe-integrated linear-spike external nozzle concept.

  17. Patterned Fibers Embedded Microfluidic Chips Based on PLA and PDMS for Ag Nanoparticle Safety Testing

    Directory of Open Access Journals (Sweden)

    Yaowen Liu

    2016-11-01

    Full Text Available A new method to integrate poly-dl-lactide (PLA patterned electrospun fibers with a polydimethylsiloxane (PDMS microfluidic chip was successfully developed via lithography. Hepatocyte behavior under static and dynamic conditions was investigated. Immunohistochemical analyses indicated good hepatocyte survival under the dynamic culture system with effective hepatocyte spheroid formation in the patterned microfluidic chip vs. static culture conditions and tissue culture plate (TCP. In particular, hepatocytes seeded in this microfluidic chip under a flow rate of 10 μL/min could re-establish hepatocyte polarity to support biliary excretion and were able to maintain high levels of albumin and urea secretion over 15 days. Furthermore, the optimized system could produce sensitive and consistent responses to nano-Ag-induced hepatotoxicity during culture. Thus, this microfluidic chip device provides a new means of fabricating complex liver tissue-engineered scaffolds, and may be of considerable utility in the toxicity screening of nanoparticles.

  18. The pattern and technique in the clinical evaluation of the adult hip: the common physical examination tests of hip specialists.

    Science.gov (United States)

    Martin, Hal D; Kelly, Bryan T; Leunig, Michael; Philippon, Marc J; Clohisy, John C; Martin, RobRoy L; Sekiya, Jon K; Pietrobon, Ricardo; Mohtadi, Nicholas G; Sampson, Thomas G; Safran, Marc R

    2010-02-01

    The purpose of this study was to systematically evaluate the technique and tests used in the physical examination of the adult hip performed by multiple clinicians who regularly treat patients with hip problems and identify common physical examination patterns. The subjects included 5 men and 6 women with a mean age (+/-SD) of 29.8 +/- 9.4 years. They underwent physical examination of the hip by 6 hip specialists with a strong interest in hip-related problems. All examiners were blind to patient radiographs and diagnoses. Patient examinations were video recorded and reviewed. It was determined that 18 tests were most frequently performed (>or=40%) by the examiners, 3 standing, 11 supine, 3 lateral, and 1 prone. Of the most frequently performed tests, 10 were performed more than 50% of the time. The tests performed in the supine position were as follows: flexion range of motion (ROM) (percentage of use, 98%), flexion internal rotation ROM (98%), flexion external rotation ROM (86%), passive supine rotation test (76%), flexion/adduction/internal rotation test (70%), straight leg raise against resistance test (61%), and flexion/abduction/external rotation test (52%). The tests performed in the standing position were the gait test (86%) and the single-leg stance phase test (77%). The 1 test in the prone position was the femoral anteversion test (58%). There are variations in the testing that hip specialists perform to examine and evaluate their patients, but there is enough commonality to form the basis to recommend a battery of physical examination maneuvers that should be considered for use in evaluating the hip. Patients presenting with groin, abdominal, back, and/or hip pain need to have a basic examination to ensure that the hip is not overlooked. A comprehensive physical examination of the hip will benefit the patient and the physician and serve as the foundation for future multicenter clinical studies. (c) 2010 Arthroscopy Association of North America. Published

  19. Fungicides efficiency on wheat diseases control in response to the application with different spray nozzles

    Directory of Open Access Journals (Sweden)

    Felipe Rafael Garcés Fiallos

    2011-12-01

    Full Text Available This study aimed to evaluate the efficiency of fungicides to leaf control diseases of wheat, when applied to different models of spray nozzles. The experiment was conducted in a randomized block design with four replicates of factorial (4 x 3+1. Data were subjected to analysis of variance and means compared by Tukey test at 5% probability. The fungicides used were: Opera® (pyraclostrobin+epoxiconazole 0.75 L.ha-1 , Opera® 0.75 L.ha-1 +Folicur® (tebuconazole 0.3 L.ha-1 , Priori Xtra® (azoxystrobin+cyproconazole 0.3 L.ha-1 , Priori Xtra® 0.3 L.ha-1 +Tilt® (propiconazole 0.3 L.ha-1 . These fungicides were applied with three models of spray nozzles jet planes: XR 11 001 (fine drop, AIRMIX 11,001 (average drop and AVI 11,001 (coarse drop. We evaluated the incidence and severity (damage per plant leaf of yellow spot (Drechslera tritici-repentis, spot blotch (Bipolaris sorokiniana, leaf rust (Puccinia triticina and grain yield (kg.ha-1 culture. The results show that the application of fungicides for control of leaf diseases in wheat resulted in increases in grain yield, and yield higher values were observed with the application of Opera®, using the XR 11001.

  20. Chocolate or orange juice for non-reactive non-stress test (NST) patterns: a randomized prospective controlled study.

    Science.gov (United States)

    Esin, Sertac; Baser, Eralp; Cakir, Caner; Ustun Tuncal, Gul Nihal; Kucukozkan, Tuncay

    2013-06-01

    The objective of the study was to compare bitter chocolate and orange juice with the control group for non-reactive non-stress test (NST) patterns and for maternal perception of fetal movements. Pregnant women who were followed-up on an outpatient basis and admitted for a NST and had a non-reactive result were randomized prospectively into bitter chocolate, orange juice and control groups. 180 patients were evaluable for the final analysis. Although there was a trend for orange juice group for having higher percentages of reactive NST patterns on control, there was no statistically significant difference between three groups (p = 0.159). Besides this, maternal perception of increased fetal movements was similar between groups (p = 0.755). The control group had lower post-test capillary blood glucose concentrations when compared with chocolate and orange juice groups (p = 0.01) and after post-hoc tests, this difference was found to be between orange juice and control groups. Although orange juice resulted in higher blood glucose levels, this was not synonymous with better NST results on control; in such a way that bitter chocolate, orange juice and no intervention had similar effects on non-reactive NST patterns and also on maternal perception of fetal movements.

  1. A computational investigation on the influence of the use of elliptical orifices on the inner nozzle flow and cavitation development in diesel injector nozzles

    International Nuclear Information System (INIS)

    Molina, S.; Salvador, F.J.; Carreres, M.; Jaramillo, D.

    2014-01-01

    Highlights: • The influence of elliptical orifices on the inner nozzle flow is compared. • Five nozzles with different elliptical and circular orifices are simulated. • Differences in the flow coefficients and cavitation morphology are observed. • Horizontal axis orifices are ease to cavitate, with a higher discharge coefficient. • A better mixing process quality is expected for the horizontal major axis nozzles. - Abstract: In this paper a computational study was carried out in order to investigate the influence of the use of elliptical orifices on the inner nozzle flow and cavitation development. With this aim, a large number of injection conditions have been simulated and analysed for 5 different nozzles: four nozzles with different elliptical orifices and one standard nozzle with circular orifices. The four elliptical nozzles differ from each other in the orientation of the major axis (vertical or horizontal) and in the eccentricity value, but keeping the same outlet section in all cases. The comparison has been made in terms of mass flow, momentum flux and other important non-dimensional parameters which help to describe the behaviour of the inner nozzle flow: discharge coefficient (C d ), area coefficient (C a ) and velocity coefficient (C v ). The simulations have been done with a code able to simulate the flow under either cavitating or non-cavitating conditions. This code has been previously validated using experimental measurements over the standard nozzle with circular orifices. The main results of the investigation have shown how the different geometries modify the critical cavitation conditions as well as the discharge coefficient and the effective velocity. In particular, elliptical geometries with vertically oriented major axis are less prone to cavitate and have a lower discharge coefficient, whereas elliptical geometries with horizontally oriented major axis are more prone to cavitate and show a higher discharge coefficient

  2. Hot-gas-side heat transfer characteristics of subscale, plug-nozzle rocket calorimeter chamber

    Science.gov (United States)

    Quentmeyer, Richard J.; Roncace, Elizabeth A.

    1993-01-01

    An experimental investigation was conducted to determine the hot-gas-side heat transfer characteristics for a liquid-hydrogen-cooled, subscale, plug-nozzle rocket test apparatus. This apparatus has been used since 1975 to evaluate rocket engine advanced cooling concepts and fabrication techniques, to screen candidate combustion chamber liner materials, and to provide data for model development. In order to obtain the data, a water-cooled calorimeter chamber having the same geometric configuration as the plug-nozzle test apparatus was tested. It also used the same two showerhead injector types that were used on the test apparatus: one having a Rigimesh faceplate and the other having a platelet faceplate. The tests were conducted using liquid oxygen and gaseous hydrogen as the propellants over a mixture ratio range of 5.8 to 6.3 at a nominal chamber pressure of 4.14 MPa abs (600 psia). The two injectors showed similar performance characteristics with the Rigimesh faceplate having a slightly higher average characteristic-exhaust-velocity efficiency of 96 percent versus 94.4 percent for the platelet faceplate. The throat heat flux was 54 MW/m(sup 2) (33 Btu/in.(sup 2)-sec) at the nominal operating condition, which was a chamber pressure of 4.14 MPa abs (600 psia), a hot-gas-side wall temperature of 730 K (1314 R), and a mixture ratio of 6.0. The chamber throat region correlation coefficient C(sub g) for a Nusselt number correlation of the form Nu =C(sub g)Re(sup 0.8)Pr(sup 0.3) averaged 0.023 for the Rigimesh faceplate and 0.026 for the platelet faceplate.

  3. A test device for premixed gas turbine combustion oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Richards, G.A.; Gemmen, R.S.; Yip, M.J.

    1996-03-01

    This report discusses design and operation of a single-nozzle test combustor for studying lean, premixed combustion oscillations from gas turbine fuel nozzles. It was used to study oscillations from a prototype fuel nozzle that produced oscillations during testing in a commercial engine. Similar, but not identical, oscillations were recorded in the test device. Basic requirements of the device design were that the flame geometry be maintained and acoustic losses be minimized; this was achieved by using a Helmholtz resonator as the combustor geometry. Surprisingly, the combustor oscillated strongly at several frequencies, without modification of the resonator. Brief survey of operating conditions suggests that it may be helpful to characterize oscillating behavior in terms of reference velocity and inlet air temperature with the rig backpressure playing a smaller role. The preliminary results do not guarantee that the single-nozzle test device will reproduce arbitrary oscillations that occur on a complete engine test. Nozzle/nozzle interactions may complicate the response, and oscillations controlled by acoustic velocities transverse to the nozzle axis may not be reproduced in a test device that relies on a bulk Helmholtz mode. Nevertheless, some oscillations can be reproduced, and the single-nozzle test device allows both active and passive control strategies to be tested relatively inexpensively.

  4. Lexical patterns in the reading comprehension section of the toefl test

    Directory of Open Access Journals (Sweden)

    Fabiana Macmillan

    2006-11-01

    Full Text Available The TOEFL (Test of English as a Foreign Language is currently one of the most widely accepted English language proficiency tests. Designed by the ETS (Educational Testing Service, the main purpose of the TOEFL is to determine whether the English language skills of a student applying to a North American college or university are adequate for enrollment into the selected program of study. This study will focus upon the third section of the TOEFL, Reading Comprehension, which consists of several passages followed by questions with different testing purposes. An adaptation of Hoey's (1991 analytical system for the analysis of lexical cohesion in authentic texts will be used to identify bonds connecting reading comprehension questions on the test to key excerpts in the passages they are related to. A number of sample reading comprehension questions taken from practice tests produced by the ETS will be analyzed. The analysis will focus on the relationship between the testing purpose of each question and the type(s of lexical link involved in the identification of the correct answer.

  5. Test for intercalary regeneration of the metameric pattern of the leafhopperEuscelis plebejus fall. (homoptera).

    Science.gov (United States)

    Vogel, Otto

    1983-09-01

    Immerging U-shaped germ bands of the leafhopperEuscelis plebejus were cut twice by constriction in order to combine the anterior and posterior ends of the embryo. Although these terminal parts fused in a number of cases, no intercalary regeneration was observed.In addition, the experiments revealed that constriction during anatrepsis (germ anlage extension) causes gaps of varying size in the abdominal part of the segment pattern.The data suggest that "differential adhesion" between yolk cells and the surface of the germ anlage might play a part in the immersion of the germ anlage into the yolk.

  6. Whiteboard icons to support the blood-test process in an emergency department: an observational study of temporal patterns.

    Science.gov (United States)

    Torkilsheyggi, Arnvør á; Hertzum, Morten; From, Gustav

    2013-01-01

    The competent treatment of emergency department (ED) patients requires an effective and efficient process for handling laboratory tests such as blood tests. This study investigates how ED clinicians go about the process, from ordering blood tests to acknowledging their results and, specifically, assesses the use of whiteboard icons to support this process. On the basis of observation and interviews we find that the blood-test process is intertwined with multiple other temporal patterns in ED work. The whiteboard icons, which indicate four temporally distinct steps in the blood-test process, support the nurses in maintaining the flow of patients through the ED and the physicians in assessing test results at timeouts. The main results of this study are, however, that the blood-test process is temporally and collaboratively complex, that the whiteboard icons pass by most of this complexity, that attending to the icons is yet another temporally sensitive activity to remember, and that whereas the assessment of test results is integral to patient treatment, the acknowledgement of having seen the results is a formal add-on, the responsibility for which is sometimes unclear.

  7. Shape modification for decreasing the spring stiffness of double-plate nozzle type spacer grid spring

    International Nuclear Information System (INIS)

    Lee, K. H.; Kang, H. S.; Song, K. N.; Yun, K. H.; Kim, H. K.

    2001-01-01

    Nozzle of the double-plated grid plays the role of the spirng to support a fuel rod as well as the coolant path in grid. The nozzle was known to be necessary to reduce the spring stiffness for supporting performance. In this study, the contact analysis between the fuel rod and the newly designed nozzle was performed by ABAQUS computer code to propose the preferable shape in term of spring performance. Two small cut at the upper and lower part of the nozzle appeared to have a minor effect in decreasing the nozzle stiffness. A long slot at the center of the nozzle was turned out not only to decrease the spring constant as desired but also to increase the elastic displacement

  8. Effects of temperature-gradient-induced damage of zirconia metering nozzles

    Science.gov (United States)

    Zhao, Liang; Xue, Qun-hu

    2017-09-01

    The effects of temperature-gradient-induced damage of zirconia metering nozzles were investigated through analysis of the phase composition and microstructure of nozzle samples. The analysis was carried out using X-ray diffraction and scanning electron microscopy after the samples were subjected to a heat treatment based on the temperatures of the affected, transition, and original layers of zirconia metering nozzles during the continuous casting of steel. The results showed that, after heat treatment at 1540, 1410, or 1300°C for a dwell time of 5 h, the monoclinic zirconia phase was gradually stabilized with increasing heat-treatment temperature. Moreover, a transformation to the cubic zirconia phase occurred, accompanied by grain growth, which illustrates that the temperature gradient in zirconia metering nozzles affects the mineral composition and microstructure of the nozzles and accelerates damage, thereby deteriorating the quality and service life of the nozzles.

  9. Evaluation of an Experimental Model for Flat-Fan Nozzles Drift in Wind Tunnel by Image Processing

    Directory of Open Access Journals (Sweden)

    S.H Fattahi

    2014-09-01

    Full Text Available Each year, millions of liters of toxic liquid, are used to combat with pests and plant diseases in farms. The wide spread use of chemical pesticides causes great environmental hazards. Particles drift is one of the main problems in spraying which results in the contamination of farm lands, humans and animals. Management of particle size is regarded as the main factor in drift control. In this study, the effect of some parameters on the size of deposited particles on non-target areas was studied using statistical method. The effects of nozzle type (orifice size, spraying pressure, spraying boom height and wind speed as effective factors on drift were examined. A horizontal wind tunnel with working section of 0.47 m wide, 0.75 m height and 5.5 m long was used for testing. Experiment was performed in the form of factorial split-plot based on randomized complete block design with two replications. Droplets were measured in the treatment combinations of the type of flat-fan nozzle with three orifice area (11003- 0.87 mm2, 11004-1.18 mm2 and 11006- 1.8 mm2, spraying pressure (150, 275 and 400 kpa, wind speed (1, 2 and 3 m s-1 and the boom height of (0.35, 0.55 and 0.75 m. Water-sensitive papers were used at intervals of 0.8, 1.6 and 2.4 m from the tip of nozzles for detecting droplets size. The factors of pressure, speed and height had positive effects on the droplet size at the desired distance, but the effect of nozzle size on droplet size was negative. In the regression model the coefficients of speed was higher than the others.

  10. Design and testing of the first 2D Prototype Vertically Integrated Pattern Recognition Associative Memory

    Energy Technology Data Exchange (ETDEWEB)

    Liu, T.; Deptuch, G.; Hoff, J.; Jindariani, S.; Joshi, S.; Olsen, J.; Tran, N.; Trimpl, M.

    2015-02-01

    An associative memory-based track finding approach has been proposed for a Level 1 tracking trigger to cope with increasing luminosities at the LHC. The associative memory uses a massively parallel architecture to tackle the intrinsically complex combinatorics of track finding algorithms, thus avoiding the typical power law dependence of execution time on occupancy and solving the pattern recognition in times roughly proportional to the number of hits. This is of crucial importance given the large occupancies typical of hadronic collisions. The design of an associative memory system capable of dealing with the complexity of HL-LHC collisions and with the short latency required by Level 1 triggering poses significant, as yet unsolved, technical challenges. For this reason, an aggressive R&D program has been launched at Fermilab to advance state of-the-art associative memory technology, the so called VIPRAM (Vertically Integrated Pattern Recognition Associative Memory) project. The VIPRAM leverages emerging 3D vertical integration technology to build faster and denser Associative Memory devices. The first step is to implement in conventional VLSI the associative memory building blocks that can be used in 3D stacking, in other words, the building blocks are laid out as if it is a 3D design. In this paper, we report on the first successful implementation of a 2D VIPRAM demonstrator chip (protoVIPRAM00). The results show that these building blocks are ready for 3D stacking.

  11. Head and Shoulders: Testing the Profitability of this Chart Pattern of Technical Analysis in the Brazilian Stock Market

    Directory of Open Access Journals (Sweden)

    Pedro Gabriel Boainain

    2009-06-01

    Full Text Available Starting from an adapted version of Osler and Chang (1995 methodology, this article empirically evaluates the profitability of investment strategies based on identification of the Head and Shoulders chart pattern in the Brazilian stock market. For that purpose, several investment strategies conditioned by the identification of the Head and Shoulders pattern (in its basic and inverted forms by a computer algorithm in daily price series of 30 stocks from January 1994 to January 2009 were defined. Confidence intervals consistent with the null hypothesis that no strategies with positive returns can be based only on historical data were constructed using the Bootstrap sample inference technique in order to test the predictive power of each strategy. More specifically, the mean returns obtained by each strategy when applied to the stock's price series were compared to those obtained by the same strategies when applied to 1.000 artificial price series -- for each stock -- generated in a parametric manner, by an E-GARCH, and in a nonparametric one. Overall, our results show that it is possible to create strategies conditioned by the occurrence of Head and Shoulders, with positive returns, which indicates that these patterns can capture from stock historical prices some signals about their future price trend that makes possible to create profitable strategies. Nevertheless, the same conclusions are not valid for the pattern in its inverted form and when the effects of taxes and transaction costs are considered, depending on their magnitude, neither in its basic form.

  12. Effect of geometrical parameters on submerged cavitation jet discharged from profiled central-body nozzle

    Science.gov (United States)

    Yang, Minguan; Xiao, Shengnan; Kang, Can; Wang, Yuli

    2013-05-01

    The flow characteristics of cavitation jets are essential issues among relevant studies. The physical properties of the jet are largely determined by the geometrical parameters of the nozzle. The structure and cavitation jets characteristics of the angular-nozzle and the self-resonating cavitation nozzle have been extensively studied, but little research is conducted in the central-body cavitation nozzle mainly because of its hard processing and the cavitation jet effect not satisfactory. In this paper, a novel central-body nozzle (a non-plunger central-body nozzle with square outlet) is studied to solve above problems. Submerged jets discharged from the novel central-body nozzle are simulated, employing the full cavitation model. The impact of nozzle configuration on jet properties is analyzed. The analysis results indicate that when central-body relative diameter keeps constant, there is an optimal contraction degree of nozzle's outlet, which can induce intense cavitation in the jet. The central-body relative diameter also affects jet profiles. In the case of large central-body relative diameter, most of the bubbles settle in the jet core. On the contrary, a smaller relative diameter makes bubbles concentrate in the interface between the jet and its surrounding fluid. Moreover, the shorter outlet part allows the cavitation zone further extend in both the axial and racial directions. The research results further consummate the study on the central-body nozzles and the correlation between cavitation jet and the structure, and elementarily reveal the mechanism of cavitation jet produced in a non-plunger novel central-body nozzle and the effect of the structure parameters on the cavitation jet, moreover, provide the theoretical basis for the optimal design of the nozzle.

  13. Performance test of a micro-pattern stereo detector with two gas electron multipliers

    Energy Technology Data Exchange (ETDEWEB)

    Barvich, T.; Bluem, P.; Erdmann, M. E-mail: martin.erdmann@cern.ch; Fahrer, M.; Kaercher, K.; Kuehn, F.; Moermann, D.; Mueller, Th.; Neuberger, D.; Roederer, F.; Simonis, H.J.; Skiba, A.; Thuemmel, W.H.; Weiler, Th.; Weseler, S

    2002-02-01

    We report on the performance of a large micro-pattern detector with two gas electron multiplier foils and a two-layer readout structure at ground potential. The two readout layers each have a 406 {mu}m pitch and cross at an effective angle of 6.7 deg. . This structure allows for two orthogonal coordinates to be determined. Using a muon beam at CERN together with a silicon tracking system, the position resolutions of the two coordinates are measured to be 50 {mu}m and 1 mm respectively (1 standard deviation). The muon detection efficiency for the two-dimensional space points reaches 96%. The detector was found to be well operational over a wide range in the settings of the different electrical fields.

  14. Performance test of a micro-pattern stereo detector with two gas electron multipliers

    International Nuclear Information System (INIS)

    Barvich, T.; Bluem, P.; Erdmann, M.; Fahrer, M.; Kaercher, K.; Kuehn, F.; Moermann, D.; Mueller, Th.; Neuberger, D.; Roederer, F.; Simonis, H.J.; Skiba, A.; Thuemmel, W.H.; Weiler, Th.; Weseler, S.

    2002-01-01

    We report on the performance of a large micro-pattern detector with two gas electron multiplier foils and a two-layer readout structure at ground potential. The two readout layers each have a 406 μm pitch and cross at an effective angle of 6.7 deg. . This structure allows for two orthogonal coordinates to be determined. Using a muon beam at CERN together with a silicon tracking system, the position resolutions of the two coordinates are measured to be 50 μm and 1 mm respectively (1 standard deviation). The muon detection efficiency for the two-dimensional space points reaches 96%. The detector was found to be well operational over a wide range in the settings of the different electrical fields

  15. Acceptance Test Report for the high pressure water jet system canister cleaning fixture

    Energy Technology Data Exchange (ETDEWEB)

    Burdin, J.R.

    1995-10-25

    This Acceptance Test confirmed the test results and recommendations, documented in WHC-SD-SNF-DTR-001, Rev. 0 Development Test Report for the High Pressure Water Jet System Nozzles, for decontaminating empty fuel canisters in KE-Basin. Optimum water pressure, water flow rate, nozzle size and overall configuration were tested

  16. Acceptance Test Report for the high pressure water jet system canister cleaning fixture

    International Nuclear Information System (INIS)

    Burdin, J.R.

    1995-01-01

    This Acceptance Test confirmed the test results and recommendations, documented in WHC-SD-SNF-DTR-001, Rev. 0 Development Test Report for the High Pressure Water Jet System Nozzles, for decontaminating empty fuel canisters in KE-Basin. Optimum water pressure, water flow rate, nozzle size and overall configuration were tested

  17. Experimental stress analysis of the attachment region of hemispherical shells with attached nozzles. Part 2b. Radial nozzle 7. 875 in. O. D. --7. 500 in. I. D. 10. 00 in. penetration

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, R.L.; Holland, R.W.; Stengl, G.R.

    1970-06-01

    The report presents the results of investigations conducted on a hemisphere with a radial nozzle of 7.875'' O.D. and 7.500'' I.D. and 10'' penetration into the hemisphere. Stress values were determined for the following five types of loadings: (1) internal pressure applied to the hemisphere and nozzle assembly, (2) an axial load applied collinear with nozzle, (3) a pure bending moment, or axial couple, applied to the nozzle, (4) a transverse or shear load applied normal to the nozzle, and (5) a pure torque applied in the radial plane of the nozzle.

  18. Fabrication and characterization of truly 3-D diffuser/nozzle microstructures in silicon

    DEFF Research Database (Denmark)

    Heschel, Matthias; Müllenborn, Matthias; Bouwstra, Siebe

    1997-01-01

    We present microfabrication and characterization of truly three-dimensional (3-D) diffuser/nozzle structures in silicon. Chemical vapor deposition (CVD), reactive ion etching (RIE), and laser-assisted etching are used to etch flow chambers and diffuser/nozzle elements. The flow behavior of the fa...... of the fabricated elements and the dependence of diffuser/nozzle efficiency on structure geometry has been investigated. The large freedom of 3-D micromachining combined with rapid prototyping allows one to characterize and optimize diffuser/nozzle structures...

  19. An Interactive Method of Characteristics Java Applet to Design and Analyze Supersonic Aircraft Nozzles

    Science.gov (United States)

    Benson, Thomas J.

    2014-01-01

    The Method of Characteristics (MOC) is a classic technique for designing supersonic nozzles. An interactive computer program using MOC has been developed to allow engineers to design and analyze supersonic nozzle flow fields. The program calculates the internal flow for many classic designs, such as a supersonic wind tunnel nozzle, an ideal 2D or axisymmetric nozzle, or a variety of plug nozzles. The program also calculates the plume flow produced by the nozzle and the external flow leading to the nozzle exit. The program can be used to assess the interactions between the internal, external and plume flows. By proper design and operation of the nozzle, it may be possible to lessen the strength of the sonic boom produced at the rear of supersonic aircraft. The program can also calculate non-ideal nozzles, such as simple cone flows, to determine flow divergence and nonuniformities at the exit, and its effect on the plume shape. The computer program is written in Java and is provided as free-ware from the NASA Glenn central software server.

  20. High performance Solid Rocket Motor (SRM) submerged nozzle/combustion cavity flowfield assessment

    Science.gov (United States)

    Freeman, J. A.; Chan, J. S.; Murph, J. E.; Xiques, K. E.

    1987-01-01

    Two and three dimensional internal flowfield solutions for critical points in the Space Shuttle solid rocket booster burn time were developed using the Lockheed Huntsville GIM/PAID Navier-Stokes solvers. These perfect gas, viscous solutions for the high performance motor characterize the flow in the aft segment and nozzle of the booster. Two dimensional axisymmetric solutions were developed at t = 20 and t = 85 sec motor burn times. The t = 85 sec solution indicates that the aft segment forward inhibitor stub produces vortices with are shed and convected downwards. A three dimensional 3.5 deg gimbaled nozzle flowfield solution was developed for the aft segment and nozzle at t = 9 sec motor burn time. This perfect gas, viscous analysis, provided a steady state solution for the core region and the flow through the nozzle, but indicated that unsteady flow exists in the region under the nozzle nose and near the flexible boot and nozzle/case joint. The flow in the nozzle/case joint region is characterized by low magnitude pressure waves which travel in the circumferential direction. From the two and three dimensional flowfield calculations presented it can be concluded that there is no evidence from these results that steady state gas dynamics is the primary mechanism resulting in the nozzle pocketing erosion experienced on SRM nozzles 8A or 17B. The steady state flowfield results indicate pocketing erosion is not directly initiated by a steady state gas dynamics phenomenon.

  1. Patterns of participation over four rounds of annual fecal immunochemical test-based screening for colorectal cancer: what predicts rescreening?

    Directory of Open Access Journals (Sweden)

    Joanne M. Osborne

    2017-08-01

    Full Text Available Abstract Background Participation at the recommended intervals is critical for screening to be effective in reducing colorectal cancer (CRC incidence. This study describes patterns of screening participation over four rounds of fecal immunochemical testing (FIT to identify whether demographic variables and prior screening satisfaction are significantly associated with patterns of re-participation. Methods Baseline surveys were mailed to 4000 South Australians randomly selected from the electoral-roll. Respondents (n = 1928/48.2% were offered four annual FIT rounds. Screening participation and satisfaction at each round were recorded. Results Study participation was 58.5, 66.9, 73.1 and 71.4% respectively over four rounds. Three participation patterns were described: consistent participation (43.1%, consistent non-participation (26.4% and inconsistent participation (changeable; 30.5%, including intermittent and sustained change patterns. Sustained change described those who changed participatory behavior and then maintained for at least two rounds (n = 375/19.5%. Older people, and those not working were most likely to sustain participation. Younger invitees, especially men, were more likely to change participatory behavior and sustain the change. People with higher disadvantage, less education, not working and with no prior (pre-trial screening experience were more likely to start participating and drop out. People dissatisfied with a prior screening test, including finding aspects embarrassing or unpleasant, were also more likely not to participate in annual screening or to drop out. Conclusions The findings identify those at risk of non- or inconsistent participation in rescreening. They should aid targeting of interventions for demographic groups at risk and ensuring screening experiences are not perceived as unpleasant or difficult.

  2. Expressing best practices in (risk) analysis and testing of safety-critical systems using patterns

    DEFF Research Database (Denmark)

    Herzner, Wolfgang; Sieverding, Sven; Kacimi, Omar

    2014-01-01

    The continuing pervasion of our society with safety-critical cyber-physical systems not only demands for adequate (risk) analysis, testing and verification techniques, it also generates growing experience on their use, which can be considered as important as the tools themselves for their efficient...

  3. The cross-national pattern of happiness. Test of predictions implied in three theories of happiness

    NARCIS (Netherlands)

    R. Veenhoven (Ruut); J.J. Ehrhardt (Joop)

    1995-01-01

    textabstractABSTRACT. Predictions about level and dispersion of happiness in nations are derived from three theories of happiness: comparison-theory, folklore-theory and livability-theory. The predictions are tested on two cross national data-sets: a comparative survey among university students in

  4. The Impact of Various Quizzing Patterns on the Test Performance of High School Economics Students

    Science.gov (United States)

    Robertson, William L.

    2010-01-01

    Presenting college students, in a wide variety of content areas, with frequent announced and unannounced quizzes appears to correlate positively with enhanced test performance. The purpose of this quantitative study was to examine if similar results can be achieved with high school students in a standard economics class. Based on a theoretical…

  5. A high power test method for pattern magnet power supplies with capacitor banks

    International Nuclear Information System (INIS)

    Kurimoto, Yoshinori; Morita, Yuichi; Shimogawa, Tetsushi; Miura, Kazuki; Sagawa, Ryu

    2015-01-01

    In the J-PARC Main Ring (MR), we plan to increase the beam intensity from 230 to 750 kW. To achieve this, the synchrotron repetition period must be shortened from 2.48 s to approximately 1 s using new power supplies for the main magnets. We are currently researching and developing new power supplies with large capacitor banks. Such banks are needed to reduce the power variation at the main grid in the J-PARC site for future operations with shorter repetition periods. However, it is very difficult to test the new power supplies at their rated power before installation. This is because the power handled by the power supplies used for the J-PARC MR main magnets is too high to be tested in factories or laboratories. To overcome this problem, we suggest a test method involving the use of two capacitor banks. In this method, two power supplies and a small inductive load are connected between two capacitor banks. By controlling the energy flow between the two capacitor banks in this setup, the received power and inductive load can be kept very small. This article describes the details of the control method and the results of the test experiment using a mini-model power supply. (author)

  6. A High Power Test Method for Pattern Magnet Power Supplies with Capacitor Banks

    Science.gov (United States)

    Kurimoto, Yoshinori; Morita, Yuichi; Sagawa, Ryu; Shimogawa, Tetsushi; Miura, Kazuki

    In the J-PARC Main Ring (MR), we plan to increase the beam intensity from 230 to 750 kW. To achieve this, the synchrotron repetition period must be shortened from 2.48 s to approximately 1 s using new power supplies for the main magnets. We are currently researching and developing new power supplies with large capacitor banks. Such banks are needed to reduce the power variation at the main grid in the J-PARC site for future operations with shorter repetition periods. However, it is very difficult to test the new power supplies at their rated power before installation. This is because the power handled by the power supplies used for the J-PARC MR main magnets is too high to be tested in factories or laboratories. To overcome this problem, we suggest a test method involving the use of two capacitor banks. In this method, two power supplies and a small inductive load are connected between two capacitor banks. By controlling the energy flow between the two capacitor banks in this setup, the received power and inductive load can be kept very small. This article describes the details of the control method and the results of the test experiment using a mini-model power supply.

  7. Real-world injury patterns associated with Hybrid III sternal deflections in frontal crash tests.

    Science.gov (United States)

    Brumbelow, Matthew L; Farmer, Charles M

    2013-01-01

    This study investigated the relationship between the peak sternal deflection measurements recorded by the Hybrid III 50th percentile male anthropometric test device (ATD) in frontal crash tests and injury and fatality outcomes for drivers in field crashes. ATD sternal deflection data were obtained from the Insurance Institute for Highway Safety's 64 km/h, 40 percent overlap crashworthiness evaluation tests for vehicles with seat belt crash tensioners, load limiters, and good-rated structure. The National Automotive Sampling System Crashworthiness Data System (NASS-CDS) was queried for frontal crashes of these vehicles in which the driver was restrained by a seat belt and air bag. Injury probability curves were calculated by frontal crash type using the injuries coded in NASS-CDS and peak ATD sternal deflection data. Fatality Analysis Reporting System (FARS) front-to-front crashes with exactly one driver death were also studied to determine whether the difference in measured sternal deflections for the 2 vehicles was related to the odds of fatality. For center impacts, moderate overlaps, and large overlaps in NASS-CDS, the probability of the driver sustaining an Abbreviated Injury Scale (AIS) score ≥ 3 thoracic injury, or any nonextremity AIS ≥ 3 injury, increased with increasing ATD sternal deflection measured in crash tests. For small overlaps, however, these probabilities decreased with increasing deflection. For FARS crashes, the fatally injured driver more often was in the vehicle with the lower measured deflection in crash tests (55 vs. 45%). After controlling for other factors, a 5-mm difference in measured sternal deflections between the 2 vehicles was associated with a fatality odds ratio of 0.762 for the driver in the vehicle with the greater deflection (95% confidence interval = 0.373, 1.449). Restraint systems that reduce peak Hybrid III sternal deflection in a moderate overlap crash test are beneficial in real-world crashes with similar or greater

  8. Thrust Enhancement in Hypervelocity Nozzles by Chemical Catalysis

    Science.gov (United States)

    Singh, D. J.; Carpenter, Mark H.; Drummond, J. P.

    1997-01-01

    In the hypersonic flight regime, the air-breathing supersonic combustion ramjet (scramjet) has been shown to be a viable propulsion system. The current designs of scramjet engines provide performance benefits only up to a Mach number of 14. Performance losses increase rapidly as the Mach number increases. To extend the applicability of scram'jets beyond Mach 14, research is being conducted in the area of inlet and wave drag reduction, skin-friction and heat-transfer reduction, nozzle loss minimization, low-loss mixing, and combustion enhancement. For high Mach number applications, hydrogen is the obvious fuel choice because of its high energy content per unit mass in comparison with conventional fuels. These flight conditions require engines to operate at supersonic internal velocities, high combustor temperatures, and low static pressures. The high static temperature condition enhances the production of radicals such as H and OH, and the low-pressure condition slows the reaction rates, particularly the recombination reactions. High-temperature and low-pressure constraints, in combination with a small residence time, result in a radical-rich exhaust gas mixture exiting the combustor. At high Mach number conditions (due to low residence time), H and OH do not have enough time to recombine ; thus, a significant amount of energy is lost as these high-energy free radical are exhausted. The objective of the present study is to conduct a flowfield analysis for a typical nozzle geometry for NASP-type vehicle to assess for thrust enhancement in hypervelocity nozzles by substituting small amount of phosphine for hydrogen.

  9. Fracture mechanics evaluation of LOFT lower plenum injection nozzle

    International Nuclear Information System (INIS)

    Nagata, P.K.; Reuter, W.G.

    1977-01-01

    An analysis to establish whether or not a leak-before-break concept would apply to the LOFT lower plenum injection nozzle is described. The analysis encompassed the structure from the inlet side of valve V-2170 to the lower plenum nozzle-to-reactor vessel weld on the left side of the emergency core cooling system (ECCS). The defect that was assumed to exist was of such a size that the probability of its being missed by the applicable inspection technique was near zero. The Inconel 600 nozzle forging with an initial assumed defect size of 0.64 cm (0.25 in.) deep would behave as follows: (1) the axially oriented defect would result in leak before rupture (the number of cycles to rupture was 11,000), (2) the circumferentially oriented defect would result in a rupture before leak. The number of cycles to failure would be in excess of 14,000. Based on the conservative assumption that the thermal stresses were membrane stresses as opposed to a bending stress, the following were found. For the Inconel 82 weld metal (thickness of 1.3 cm [0.53 in.]) and AISI 316 SST valve body, with an initial assumed defect of 0.25 cm (0.1 in.), the crack would grow through the thickness in a minimum of 3950 cycles and to a critical rupture crack length of 5.1 cm (2.0 in.) in an additional 80 cycles. The Inconel 82 weld metal at the shell body (thickness of 9.7 cm or 3.8 in.) with an assumed defect 1.3 cm (0.5 in.) deep would fail in 334 cycles. Calculations made assuming a linear stress gradient instead of the above-mentioned flat distribution through the wall indicated that the number of stress cycles increased to 2200

  10. A test of the influence of continental axes of orientation on patterns of human gene flow

    Science.gov (United States)

    Ramachandran, Sohini; Rosenberg, Noah A.

    2012-01-01

    The geographic distribution of genetic variation reflects trends in past population migrations, and can be used to make inferences about these migrations. It has been proposed that the east-west orientation of the Eurasian landmass facilitated the rapid spread of ancient technological innovations across Eurasia, while the north-south orientation of the Americas led to a slower diffusion of technology there. If the diffusion of technology was accompanied by gene flow, then this hypothesis predicts that genetic differentiation in the Americas along lines of longitude will be greater than that in Eurasia along lines of latitude. We use 678 microsatellite loci from 68 indigenous populations in Eurasia and the Americas to investigate the spatial axes that underlie population-genetic variation. We find that genetic differentiation increases more rapidly along lines of longitude in the Americas than along lines of latitude in Eurasia. Distance along lines of latitude explains a sizeable portion of genetic distance in Eurasia, whereas distance along lines of longitude does not explain a large proportion of Eurasian genetic variation. Genetic differentiation in the Americas occurs along both latitudinal and longitudinal axes and has a greater magnitude than corresponding differentiation in Eurasia, even when adjusting for the lower level of genetic variation in the American populations. These results support the view that continental orientation has influenced migration patterns and has played an important role in determining both the structure of human genetic variation and the distribution and spread of cultural traits. (240 words) PMID:21913175

  11. Adaptive patterns of movement during arm elevation test in patients with shoulder impingement syndrome.

    Science.gov (United States)

    Lin, Jiu-jenq; Hsieh, Shih-Chang; Cheng, Wei-Cheng; Chen, Wei Chun; Lai, Yuta

    2011-05-01

    The purpose of this study was to determine if a distinctive characteristic exists in the pattern of movement (scapular elevation and upward rotation to reduce impingement) and associated muscular activities during arm elevation in subjects with shoulder impingement (SI) that is associated with the severity of the disease. Fourteen subjects (7 amateur athletes and 7 student athletes) with SI and 7 controls performed arm elevation in the scapular plane. Scapular kinematics (upward rotation, elevation, tipping, and scapulohumeral rhythm) and muscular activity [upper trapezius (UT), lower trapezius (LT), serratus anterior (SA), and deltoid] were measured by an electromagnetic motion tracking system and surface electromyography, respectively. Subjects with SI had greater elevation of the scapula (11.9 mm, p impingement during arm elevation in subjects with SI. Assessing scapular elevation during arm elevation may be a useful functional marker for evaluating impingement status and associated muscle function. Additionally, SA and LT muscle strengthening may improve SI. Copyright © 2010 Orthopaedic Research Society.

  12. Numerical modelling of the jet nozzle enrichment process

    International Nuclear Information System (INIS)

    Vercelli, P.

    1983-01-01

    A numerical model was developed for the simulation of the isotopic enrichment produced by the jet nozzle process. The flow was considered stationary and under ideal gas conditions. The model calculates, for any position of the skimmer piece: (a) values of radial mass concentration profiles for each isotopic species and (b) values of elementary separation effect (Σ sub(A)) and uranium cut (theta). The comparison of the numerical results obtained with the experimental values given in the literature proves the validity of the present work as an initial step in the modelling of the process. (Author) [pt

  13. Weld failure analysis of 2205 duplex stainless steel nozzle

    Directory of Open Access Journals (Sweden)

    Jingqiang Yang

    2014-10-01

    Full Text Available Failure analyses of weld joint between the nozzle and the head of the reactor made of 2205 duplex stainless steel was performed by optical microscopy (OM and scanning electron microscopy (SEM. Cracks were found in HAZ of the weld. The depth of the cracks is equal to the thickness of the inner weld. Localized uneven distribution of ferrite/austenite with 80–90% ferrite in weld is found. Results show that the cracks occurred along columnar granular with cleavage fracture. Poor weld process probably results in these cracks.

  14. Weld failure analysis of 2205 duplex stainless steel nozzle

    OpenAIRE

    Jingqiang Yang; Qiongqi Wang; Zhongkun Wei; Kaishu Guan

    2014-01-01

    Failure analyses of weld joint between the nozzle and the head of the reactor made of 2205 duplex stainless steel was performed by optical microscopy (OM) and scanning electron microscopy (SEM). Cracks were found in HAZ of the weld. The depth of the cracks is equal to the thickness of the inner weld. Localized uneven distribution of ferrite/austenite with 80–90% ferrite in weld is found. Results show that the cracks occurred along columnar granular with cleavage fracture. Poor weld process pr...

  15. Evaluation of Nozzle Arrangement Focused on RPV Integrity

    International Nuclear Information System (INIS)

    Kim, Jong Wook; Lee, Gyu Mahn; Jeoung, Kyeong Hoon; Kim, Tae Wan; Park, Keun Bae; Kim, Keung Koo

    2008-10-01

    The purpose of this study is to investigate the fabrication capacity of the reactor pressure vessel. For that reason, this study focuses on survey of the domestic equipment capacity and the feasible size for reactor pressure vessel. Also, the forecasting issues of adoption of new material for reactor pressure vessel are reviewed through typically examples. Additionally, an evaluation procedure for the design of nozzle is developed to meet ASME code requirements. The developed design procedure could provide typical references for the development of advanced reactor design in the future

  16. Assembly meshing of abrasive waterjet nozzle erosion simulation

    Science.gov (United States)

    Kamarudin, N. H.; Mebrahitom, A.; Azhari, A.

    2018-01-01

    Computational Fluid Dynamics (CFD) softwares have been prevalent in Abrasive Waterjet (AWJ) Modelling for optimization and prediction. However, there are many different methods in approaching a single problem especially in predicting the erosion rate of nozzle which is critical in influencing kerf quality of AWJ cutting. In this paper, three main methods of assembly meshing for an abrasive waterjet erosion were simulated which is Quadrilateral, Cutcell and Tetrahedrons and each processing time, quality of convergence and accuracy of results are discussed. Results shows that Quadrilateral mesh prevails in the mentioned category followed by Tetrahedrons and Cutcell.

  17. Supersonic minimum length nozzle design for dense gases

    Science.gov (United States)

    Aldo, Andrew C.; Argrow, Brian M.

    1993-01-01

    Recently, dense gases have been investigated for many engineering applications such as for turbomachinery and wind tunnels. Supersonic nozzle design for these gases is complicated by their nonclassical behavior in the transonic flow regime. In this paper a method of characteristics (MOC) is developed for two-dimensional (planar) and, primarily, axisymmetric flow of a van der Waals gas. Using a straight aortic line assumption, a centered expansion is used to generate an inviscid wall contour of minimum length. The van der Waals results are compared to previous perfect gas results to show the real gas effects on the flow properties and inviscid wall contours.

  18. Patterns, Policy and Appropriateness: A 12-Year Utilization Review of Blood Glucose Test Strip Use in Insulin Users.

    Science.gov (United States)

    Falk, Jamie; Friesen, Kevin J; Okunnu, Anuoluwapo; Bugden, Shawn

    2017-08-01

    Considerable attention has been paid to the rising costs of the use of blood glucose test strips (BGTS). Insulin users have generally been treated as a single homogeneous group, resulting in policies that cap usage (8.2 strips/day) in provincial drug insurance programs. The objective of this study was to conduct a utilization review of BGTS by insulin users and to evaluate use patterns against current insulin use patterns and BGTS policy. BGTS usage was examined in a cohort of insulin users with type 1 and type 2 diabetes over a 12-year period (2001 to 2013) using the population-based administrative data in Manitoba, Canada. Total BGTS strip use increased by 121%, from $4.3 to $9.5 million. However, the number of insulin users also increased by 115%. Use has been stable at 1.5 strips per day per person since 2004 by insulin users with type 2 diabetes but has risen from 1.9 to 3.0 strips per day per person in those with type 1 diabetes. Mean daily test strip use was below the number of daily tests recommended for patients using insulin as per the current Canadian guidelines, with 11% and 15% of insulin users with type 1 and type 2 diabetes not claiming any BGTS use and a further 15% (type 1) and 28% (type 2) using fewer than 1 strip per day. BGTS use per insulin user has been stable for most of the past decade, and the vast majority of use falls well below provincial insurance caps. The amount of low-level testing (0 to <1 strip/day) suggests that greater attention should be directed to ensuring a safe level of testing by all insulin users. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  19. Pulmonary sarcoidosis: correlation of expiratory high-resolution CT findings with inspiratory patterns and pulmonary function tests

    International Nuclear Information System (INIS)

    Magkanas, E.; Voloudaki, A.; Bouros, D.; Prassopoulos, P.; Alexopoulou, C.; Tzanakis, N.; Gourtsoyiannis, N.; Linardakis, M.

    2001-01-01

    Purpose: To assess the presence and extent of air trapping (AT) on chest high-resolution CT (HRCT) in sarcoidosis and to correlate such findings with patterns, lesion extent on inspiratory CT and pulmonary function tests (PFT). Material and Methods: Thirty patients with sarcoidosis underwent inspiratory and expiratory HRCT and PFT. HRCT images were evaluated for presence, distribution and AT extent as well as the predominant HRCT pattern and the extent of lesions at inspiration. Attenuation difference in the AT regions at expiration and at inspiration were calculated. The presence and extent of AT were correlated with PFT, extent of involvement and predominant inspiratory patterns. Results: AT was present in 25/30 patients with no lung zone predilection. AT was the only CT indication of pulmonary sarcoidosis in 3/30 patients who also had normal PFT. Attenuation difference between inspiration and expiration ranged from -40 HU to 106 HU. In 2 patients, a paradoxical decrease of lung attenuation was observed at expiration. A significant correlation was found between AT extent at expiration, with residual volume-total lung capacity ratio and residual volume. Conclusion: AT is an additional HRCT finding in sarcoidosis. AT may involve any lung zone, including costophrenic angles and may be the only CT feature of pulmonary sarcoidosis. Strong correlation is only found with PFT values that are specific for incomplete lung emptying at expiration

  20. An Investigation of Transonic Resonance in a Mach 2.2 Round Convergent-Divergent Nozzle

    Science.gov (United States)

    Dippold, Vance F., III; Zaman, Khairul B. M. Q.

    2015-01-01

    Hot-wire and acoustic measurements were taken for a round convergent nozzle and a round convergent-divergent (C-D) nozzle at a jet Mach number of 0.61. The C-D nozzle had a design Mach number of 2.2. Compared to the convergent nozzle jet flow, the Mach 2.2 nozzle jet flow produced excess broadband noise (EBBN). It also produced a transonic resonance tone at 1200 Herz. Computational simulations were performed for both nozzle flows. A steady Reynolds-Averaged Navier-Stokes simulation was performed for the convergent nozzle jet flow. For the Mach 2.2 nozzle flow, a steady RANS simulation, an unsteady RANS (URANS) simulation, and an unsteady Detached Eddy Simulation (DES) were performed. The RANS simulation of the convergent nozzle showed good agreement with the hot-wire velocity and turbulence measurements, though the decay of the potential core was over-predicted. The RANS simulation of the Mach 2.2 nozzle showed poor agreement with the experimental data, and more closely resembled an ideally-expanded jet. The URANS simulation also showed qualitative agreement with the hot-wire data, but predicted a transonic resonance at 1145 Herz. The DES showed good agreement with the hot-wire velocity and turbulence data. The DES also produced a transonic tone at 1135 Herz. The DES solution showed that the destabilization of the shock-induced separation region inside the nozzle produced increased levels of turbulence intensity. This is likely the source of the EBBN.

  1. Experimental investigation on the effect of injection conditions on spray and atomization of a centrifugal nozzle

    Science.gov (United States)

    Fan, Wei; Song, Haoyi; Fan, Zhencen; Zhao, Lin

    2013-05-01

    The effects of injection parameters on atomization of aviation kerosene (RP-3) were studied using a laser diffraction particle size analyzing system. The test results indicated that Sauter mean diameter (SMD) decreased with the increase of injection temperature. There was a critical temperature for flash evaporation, at which SMD had a sharp decrease. The critical temperature fell at first and then rose with the increase of injection pressure; however, the diameter of a centrifugal nozzle had little influence on the critical temperature. Sauter mean diameter didn't follow the conventional law after flash evaporation. A simple and empirical correlation between critical temperature for flash evaporation and injection parameters was developed from the experimental data, which can be used to evaluate critical temperature for flash evaporation.

  2. Non-spherical surface wave amplitude radiation patterns identified from spectral ratios of the 2016 and 2013 DPRK nuclear tests

    Science.gov (United States)

    Ichinose, G. A.; Ford, S. R.; Myers, S.; Pasyanos, M.; Walter, W. R.

    2016-12-01

    The 6 January 2016, 12 February 2013 and 25 May 2009 declared nuclear explosions at the Punggye-ri test site in the Democratic People's Republic of Korea (DPRK) were all closely located providing an opportunity to perform differential analysis. We used spectral ratios of surface waves between 50 and 10 sec period between the co-located events to isolate relative explosion amplitude radiation patterns by the cancelation of propagation and site effects. We calculated the spectral ratios using a dense array of 72 NIED F-NET stations across Japan and all available IMS, IC and IU network stations. Analyses of Rayleigh waves indicated non-spherical radiation for the 2016 and 2013 tests relative to 2009. The 2016/2009 and 2013/2009 event pairs had ellipsoidal radiation patterns. The 2016/2009 pair had an ellipse major axis oriented 123 degrees from north and the 2013/2009 pair was oriented 33 degrees from north. This suggests that both 2016 and 2013 explosions have non-spherical radiation and also that the radiation between 2016 and 2013 were rotated by 90 degrees. This radiation pattern was strongest in the 20 and 33 sec period band but was also observed in the 10 and 50 sec band with higher scatter. We did not discern any Love wave radiation patterns but there is high scatter possibly due to a lower long-period signal to noise ratio on the horizontal relative to the vertical components. There are several possible source models that can theoretically cause non-spherical radiation, for example topography, spall damage, or tectonic release. One implication we have identified is that the radiation pattern makes it problematic for the use of surface waves in relative relocations, typically more robust for earthquakes. The amount of departure from purely spherical radiation is consistent with the 20-30% CLVD and 60-70% isotropic components estimated from regional long-period moment tensor solutions for the two explosions. This work performed under the auspices of the US

  3. The onset, development, basic patterns and empirical norms of DSQ-40 psychological test

    Directory of Open Access Journals (Sweden)

    Čabarkapa Milanko M.

    2002-01-01

    Full Text Available Psychological defence mechanisms represent relatively stable aspect of personality, while character and frequency of defence mechanisms which a person uses, points to the character structure of personality. Measuring psychological defence mechanisms is very difficult and very unreliable, so that only several instruments have been developed for the estimation of such characteristics. The most notable instrument of this kind in the world is DSQ-40 (Defense Style Questionnaire, which has lately been more often used in our country. As DSQ-40 is still not widely known in our environment, the aim of this study was to represent the onset and the development of this test, its basic characteristics and empirical norms acquired on our population. Examination included two examined groups in military population of male sex only: soldiers of adolescent age (n=400 and officers of the adult age (n=165. Statistical analysis and the comparison of the results with corresponding standards obtained in foreign researches showed that defence style and structure of psychological defence mechanisms were connected with socio-demographic and cultural characteristics of examinees. It was concluded that norms of the test DSQ-40 must be adjusted to the concrete population, which hasn't diminished its practical values and employment in diagnostic and selection purposes.

  4. Experimental study of the injection conditions influence over n-dodecane and diesel sprays with two ECN single-hole nozzles. Part I: Inert atmosphere

    International Nuclear Information System (INIS)

    Gimeno, Jaime; Bracho, Gabriela; Martí-Aldaraví, Pedro; Peraza, Jesús E.

    2016-01-01

    In this research, two Engine Combustion Network (ECN) mono-orifice nozzles, referred to as Spray C and Spray D respectively, were analyzed by performing visualization tests through Schlieren and Diffused Backlight Illumination (DBI) techniques under a wide range of ambient conditions in a non-reactive atmosphere. Spray C presents a straight nozzle designed with a sharp fillet in opposition to Spray D that has similar hydraulic properties, but with a convergent nozzle construction and a smoother corner. The experiments were carried out injecting two distinct fuels at different injection pressure ranges, from 50 MPa to 150 MPa with n-dodecane and to 200 MPa for diesel. The images were processed with Matlab home-built routines to calculate parameters as spray penetration, spreading angle, quasi-steady liquid length, as well as the spray penetration derivative respect to the square root of time, presented in this document as R-parameter. The results showed a clear influence of nozzle geometry in all measured parameters, due mainly to the nature of Spray C to cavitation, which increase the spreading angle and consequently a reduction in vapor penetration. On the other hand, fuel properties also affected spray penetration due to its dependency on viscous forces expressed in terms of the Reynolds number and its volatility in case of liquid length. This last parameter was calculated employing two processing methodologies, finding a good general agreement between them.

  5. BWR feedwater nozzle and control rod drive return line nozzle cracking: resolution of generic technical activity A-10. Technical report

    International Nuclear Information System (INIS)

    Snaider, R.

    1980-11-01

    This report summarizes work performed by the NRC staff in the resolution of Generic Technical Activity A-10, 'BWR Nozzle Cracking'. Generic Technical Activity A-10 is one of the generic technical subjects designated as 'unresolved safety issues' pursuant to Section 210 of the Energy Reorganization Act of 1974. The report describes the technical issues, the technical studies and analyses performed by the General Electric Company and the NRC staff, the staff's technical positions based on these studies, and the staff's plans for continued implementation of its technical positions. It also provides information for further work to resolve the non-destructive examination issue

  6. Comparison of acoustic data from a 102 mm conic nozzle as measured in the RAE 24-foot wind tunnel and the NASA Ames 40- by 80-foot wind tunnel

    Science.gov (United States)

    Atencio, A., Jr.; Mckie, J.

    1982-01-01

    A cooperative program between the Royal Aircraft Establishment (RAE), England, and the NASA Ames Research Center was initiated to compare acoustic measurements made in the RAE 24-foot wind tunnel and in the Ames 40- by 80-foot wind tunnel. The acoustic measurements were made in both facilities using the same 102 mm conical nozzle supplied by the RAE. The nozzle was tested by each organization using its respective jet test rig. The mounting hardware and nozzle exit conditions were matched as closely as possible. The data from each wind tunnel were independently analyzed by the respective organization. The results from these tests show good agreement. In both facilities, interference with acoustic measurement is evident at angles in the forward quadrant.

  7. Pattern of c-Fos expression induced by tail suspension test in the mouse brain

    Directory of Open Access Journals (Sweden)

    Kentaro Hiraoka

    2017-06-01

    Full Text Available The tail suspension test (TST has been widely used as a screening assay for antidepressant drugs. However, the neural substrates underlying the stress response and antidepressant-like effect during the TST remain largely unknown despite the prevalence of this test. In the present study, we used immunohistochemistry to examine alterations in c-Fos expression as a measure of neuronal activity in the mouse brain after acute administration of the antidepressant drugs nortriptyline or escitalopram (or saline as a control with or without a subsequent TST session. We found that without the TST session, nortriptyline administration enhanced the density of c-Fos-immunoreactive cells in regions of the central extended amygdala, paraventricular hypothalamic nucleus, and relevant regions of the brain stem, whereas escitalopram did not change c-Fos expression in any region. Following the TST in the absence of antidepressant drugs, we observed a significant increase in c-Fos-positive cell density in a number of brain regions within the limbic telencephalon, hypothalamus, and brain stem. We detected a statistically significant interaction using an analysis of variance between the main effects of the drug and stress response in four regions: the infralimbic cortex, lateral septal nucleus (intermediate part, ventrolateral preoptic nucleus, and solitary nucleus. Following the TST, escitalopram but not nortriptyline increased c-Fos-positive cell density in the infralimbic cortex and ventrolateral preoptic nucleus, whereas nortriptyline but not escitalopram increased c-Fos expression in the solitary nucleus. Both antidepressants significantly increased c-Fos expression in the lateral septal nucleus (intermediate part. The present results indicate that neuronal activity increases in septo-hypothalamic regions and related structures, especially the lateral septal nucleus, following administration of drugs producing an antidepressant-like effect in mice subjected to

  8. Development of base pressure similarity parameters for application to space shuttle launch vehicle power-on aerodynamic testing

    Science.gov (United States)

    Sulyma, P. R.; Penny, M. M.

    1978-01-01

    A base pressure data correlation study was conducted to define exhaust plume similarity parameters for use in Space Shuttle power-on launch vehicle aerodynamic test programs. Data correlations were performed for single bodies having, respectively, single and triple nozzle configurations and for a triple body configuration with single nozzles on each of the outside bodies. Base pressure similarity parameters were found to differ for the single nozzle and triple nozzle configurations. However, the correlation parameter for each was found to be a strong function of the nozzle exit momentum. Results of the data base evaluation are presented indicating an assessment of all data points. Analytical/experimental data comparisons were made for nozzle calibrations and correction factors derived, where indicated for use in nozzle exit plane data calculations.

  9. Acoustic Investigation of Jet Mixing Noise in Dual Stream Nozzles

    Science.gov (United States)

    Khavaran, Abbas; Dahl, Milo D.

    2012-01-01

    In an earlier study, a prediction model for jet noise in dual stream jets was proposed that is founded on velocity scaling laws in single stream jets and similarity features of the mean velocity and turbulent kinetic energy in dual stream flows. The model forms a composite spectrum from four component single-stream jets each believed to represent noise-generation from a distinct region in the actual flow. While the methodology worked effectively at conditions considered earlier, recent examination of acoustic data at some unconventional conditions indicate that further improvements are necessary in order to expand the range of applicability of the model. The present work demonstrates how these predictions compare with experimental data gathered by NASA and industry for the purpose of examining the aerodynamic and acoustic performance of such nozzles for a wide range of core and fan stream conditions. Of particular interest are jets with inverted velocity and temperature profiles and the appearance of a second spectral peak at small aft angles to the jet under such conditions. It is shown that a four-component spectrum succeeds in modeling the second peak when the aft angle refraction effects are properly incorporated into the model. A tradeoff of noise emission takes place between two turbulent regions identified as transition and fully mixed regions as the fan stream velocity exceeds that of the core stream. The effect of nozzle discharge coefficients will also be discussed.

  10. Sludge mobilization with submerged nozzles in horizontal cylindrical tanks

    International Nuclear Information System (INIS)

    Hylton, T.D.; Cummins, R.L.; Youngblood, E.L.; Perona, J.J.

    1995-10-01

    The Melton Valley Storage Tanks (MVSTs) and the evaporator service tanks at the Oak Ridge National Laboratory (ORNL) are used for the collection and storage of liquid low-level waste (LLLW). Wastes collected in these tanks are typically acidic when generated and are neutralized with sodium hydroxide to protect the tanks from corrosion; however, the high pH of the solution causes the formation of insoluble compounds that precipitate. These precipitates formed a sludge layer approximately 0.6 to 1.2 m (2 to 4 ft) deep in the bottom of the tanks. The sludge in the MVSTs and the evaporator service tanks will eventually need to be removed from the tanks and treated for final disposal or transferred to another storage facility. The primary options for removing the sludge include single-point sluicing, use of a floating pump, robotic sluicing, and submerged-nozzle sluicing. The objectives of this study were to (1) evaluate the feasibility of submerged-nozzle sluicing in horizontal cylindrical tanks and (2) obtain experimental data to validate the TEMPEST (time-dependent, energy, momentun, pressure, equation solution in three dimensions) computer code

  11. UT inspection of nozzles by 3D raytracing

    International Nuclear Information System (INIS)

    Isenberg, J.; Koshy, M.; Carcione, L.

    2004-01-01

    This paper documents how we have adapted 3D geometric modeling and ray tracing to support design and verification of wedges and preparation of coverage maps for ultrasonic inspection of BWR nozzles. This software is capable of addressing a broad range of modeling issues, including ray tracing in completely general 3D objects comprised of blocky, transversely isotropic material. However, to capitalize on the full range of capability usually requires an investment of time on the part of users. To make 3D modeling accessible to users who have time-urgent requirements or who do not need to utilize the full capabilities of the software, we have developed specialized applications in which restrictions on generality are accepted in exchange for easy access to model building, wedge design and coverage maps for detecting flaws in the bore and inner blend regions of nozzles. This is done by providing partially-completed, parametrized models which give the user latitude to generate general models within a fixed framework. We also provide a graphical user interface which anticipates certain tasks that a user will wish to undertake; other tasks may readily be added. (author)

  12. Experimental observations of a complex, supersonic nozzle concept

    Science.gov (United States)

    Magstadt, Andrew; Berry, Matthew; Glauser, Mark; Ruscher, Christopher; Gogineni, Sivaram; Kiel, Barry; Skytop Turbulence Labs, Syracuse University Team; Spectral Energies, LLC. Team; Air Force Research Laboratory Team

    2015-11-01

    A complex nozzle concept, which fuses multiple canonical flows together, has been experimentally investigated via pressure, schlieren and PIV in the anechoic chamber at Syracuse University. Motivated by future engine designs of high-performance aircraft, the rectangular, supersonic jet under investigation has a single plane of symmetry, an additional shear layer (referred to as a wall jet) and an aft deck representative of airframe integration. Operating near a Reynolds number of 3 ×106 , the nozzle architecture creates an intricate flow field comprised of high turbulence levels, shocks, shear & boundary layers, and powerful corner vortices. Current data suggest that the wall jet, which is an order of magnitude less energetic than the core, has significant control authority over the acoustic power through some non-linear process. As sound is a direct product of turbulence, experimental and analytical efforts further explore this interesting phenomenon associated with the turbulent flow. The authors acknowledge the funding source, a SBIR Phase II project with Spectral Energies, LLC. and AFRL turbine engine branch under the direction of Dr. Barry Kiel.

  13. BRCA testing, treatment patterns and survival in platinum-sensitive recurrent ovarian cancer - an observational cohort study.

    Science.gov (United States)

    Unni, Sudhir K; Schauerhamer, Marisa B; Deka, Rishi; Tyczynski, Jerzy E; Fernandes, Ancilla W; Stevens, Vanessa; Brixner, Diana I; Stenehjem, David D

    2016-03-22

    Breast cancer associated (BRCA) genes are critical for DNA repair. Mutations in BRCA1 and BRCA2 (BRCAm) result in loss of these repair mechanisms and potential carcinogenesis. Germline BRCAm are common in ovarian carcinomas, particularly in platinum-sensitive disease. The increased prevalence of BRCAm in platinum-sensitive disease is likely due to enhanced responsiveness to platinum chemotherapy from homologous recombination repair deficiency. The purpose of this study was to explore BRCA testing, treatment patterns and survival in platinum-sensitive recurrent (PSR) ovarian cancer. This was an observational cohort analysis of PSR ovarian cancer treated at the Huntsman Cancer Institute from 1995 to 2012. Germline BRCA status was ascertained through chart review and categorized as BRCAm (BRCA1/2 positive), BRCAwt (BRCA wild type or variant of uncertain significance), and untested. Treatment patterns and survival were assessed from recurrence until death or last follow-up. The Kaplan-Meier method was used to evaluate survival from recurrence by BRCA status. Logistic regression and COX proportional hazard model was used to estimate predictors of BRCA testing and survival, respectively. Of the 168 PSR patients, 15 (9 %) were BRCAm, 25 (15 %) were BRCAwt, and 128 (76 %) were untested. Median age at PSR was 56 years for BRCAm and BRCAwt (p = 0.90) and 63 years for those untested (p = 0.033 vs BRCAm). Overall survival was similar between BRCAm and BRCAwt (median 50.4 vs 67.5 months, p = 0.86) and was 24.9 months in untested patients. Significant predictors for the likelihood of BRCA testing were age (OR = 0.93, 95 % CI 0.89, 0.97, p = 0.002), family history of breast or ovarian cancer (OR = 8.33, 95 % CI: 3.08, 22.59, p < 0.001), and cancer diagnosis year (OR = 10.02, 95 % CI: 3.22, 31.21, p < 0.001). BRCA-tested patients had a lower risk of death versus untested (HR 0.35, 95 % CI 0.17, 0.68, p = 0.001). BRCAwt patients had similar outcomes to BRCAm patients, potentially

  14. Predictive Modeling of Fast-Curing Thermosets in Nozzle-Based Extrusion

    Science.gov (United States)

    Xie, Jingjin; Randolph, Robert; Simmons, Gary; Hull, Patrick V.; Mazzeo, Aaron D.

    2017-01-01

    This work presents an approach to modeling the dynamic spreading and curing behavior of thermosets in nozzle-based extrusions. Thermosets cover a wide range of materials, some of which permit low-temperature processing with subsequent high-temperature and high-strength working properties. Extruding thermosets may overcome the limited working temperatures and strengths of conventional thermoplastic materials used in additive manufacturing. This project aims to produce technology for the fabrication of thermoset-based structures leveraging advances made in nozzle-based extrusion, such as fused deposition modeling (FDM), material jetting, and direct writing. Understanding the synergistic interactions between spreading and fast curing of extruded thermosetting materials will provide essential insights for applications that require accurate dimensional controls, such as additive manufacturing [1], [2] and centrifugal coating/forming [3]. Two types of thermally curing thermosets -- one being a soft silicone (Ecoflex 0050) and the other being a toughened epoxy (G/Flex) -- served as the test materials in this work to obtain models for cure kinetics and viscosity. The developed models align with extensive measurements made with differential scanning calorimetry (DSC) and rheology. DSC monitors the change in the heat of reaction, which reflects the rate and degree of cure at different crosslinking stages. Rheology measures the change in complex viscosity, shear moduli, yield stress, and other properties dictated by chemical composition. By combining DSC and rheological measurements, it is possible to establish a set of models profiling the cure kinetics and chemorheology without prior knowledge of chemical composition, which is usually necessary for sophisticated mechanistic modeling. In this work, we conducted both isothermal and dynamic measurements with both DSC and rheology. With the developed models, numerical simulations yielded predictions of diameter and height of

  15. Estimation of Efficiency of the Cooling Channel of the Nozzle Blade of Gas-Turbine Engines

    Science.gov (United States)

    Vikulin, A. V.; Yaroslavtsev, N. L.; Zemlyanaya, V. A.

    2018-02-01

    The main direction of improvement of gas-turbine plants (GTP) and gas-turbine engines (GTE) is increasing the gas temperature at the turbine inlet. For the solution of this problem, promising systems of intensification of heat exchange in cooled turbine blades are developed. With this purpose, studies of the efficiency of the cooling channel of the nozzle blade in the basic modification and of the channel after constructive measures for improvement of the cooling system by the method of calorimetry in a liquid-metal thermostat were conducted. The combined system of heat-exchange intensification with the complicated scheme of branched channels is developed; it consists of a vortex matrix and three rows of inclined intermittent trip strips. The maximum value of hydraulic resistance ξ is observed at the first row of the trip strips, which is connected with the effect of dynamic impact of airflow on the channel walls, its turbulence, and rotation by 117° at the inlet to the channels formed by the trip strips. These factors explain the high value of hydraulic resistance equal to 3.7-3.4 for the first row of the trip strips. The obtained effect was also confirmed by the results of thermal tests, i.e., the unevenness of heat transfer on the back and on the trough of the blade is observed at the first row of the trip strips, which amounts 8-12%. This unevenness has a fading character; at the second row of the trip strips, it amounts to 3-7%, and it is almost absent at the third row. At the area of vortex matrix, the intensity of heat exchange on the blade back is higher as compared to the trough, which is explained by the different height of the matrix ribs on its opposite sides. The design changes in the nozzle blade of basic modification made it possible to increase the intensity of heat exchange by 20-50% in the area of the vortex matrix and by 15-30% on the section of inclined intermittent trip strips. As a result of research, new criteria dependences for the

  16. High-Speed Additive Manufacturing Through High-Aspect-Ratio Nozzles

    Science.gov (United States)

    Shaw, Leon; Islam, Mashfiqul; Li, Jie; Li, Ling; Ayub, S. M. Imran

    2018-01-01

    The feasibility of layer-by-layer manufacturing through high-aspect-ratio (HAR) nozzles for microextrusion of paste to deposit planes has been investigated. Various conditions for paste extrusion, including nozzle moving speed, piston speed, extrusion rate, and distance between the nozzle tip and substrate, have been evaluated. By linking various microextrusion parameters together with the aid of a critical distance concept derived from microextrusion using circular nozzles and addressing the extrusion delay in response to the change of the piston speed and air pocket problems properly, we successfully microextruded single planes, multilayer objects, and larger planes made of multiple smaller planes side by side through HAR nozzles. It is further demonstrated that the X-Y dimensions of an extruded plane in the steady-state extrusion stage are determined by the nozzle travel distance and the length of the HAR nozzle opening if microextrusion is conducted with proper conditions. However, the height of the extruded plane is not only determined by the microextrusion conditions, but also affected by the drying shrinkage of the paste after microextrusion. This demonstration of the feasibility of using a HAR nozzle machine opens the door to manufacture of multimaterial, multilayer devices with high productivity in the near future.

  17. Effect of Turbine Axial Nozzle-Wheel Clearance on Performance of Mark 25 Torpedo Power Plant

    Science.gov (United States)

    Hoyt, Jack W.; Kottas, Harry

    1948-01-01

    Investigations were made of the turbine from a Mark 25 torpedo to determine the performance of the unit with three different turbine nozzles at various axial nozzle-wheel clearances. Turbine efficiency with a reamed nondivergent nozzle that uses the axial clearance space for gas expansion was little affected by increasing the axial running clearance from 0.030 to 0.150 inch. Turbine efficiency with cast nozzles that expanded the gas inside the nozzle passage was found to be sensitive to increased axial nozzle-wheel clearance. A cast nozzle giving a turbine brake efficiency of 0.525 at an axial running clearance of 0.035 inch gave a brake efficiency of 0.475 when the clearance was increased to 0.095 inch for the same inlet-gas conditions and blade-jet speed ratio. If the basis for computing the isentropic power available to the turbine is the temperature inside the nozzle rather then the temperature in the inlet-gas pipe, an increase in turbine efficiency of about 0.01 is indicated.

  18. Hybrid two fuel system nozzle with a bypass connecting the two fuel systems

    Science.gov (United States)

    Varatharajan, Balachandar [Cincinnati, OH; Ziminsky, Willy Steve [Simpsonville, SC; Yilmaz, Ertan [Albany, NY; Lacy, Benjamin [Greer, SC; Zuo, Baifang [Simpsonville, SC; York, William David [Greer, SC

    2012-05-29

    A hybrid fuel combustion nozzle for use with natural gas, syngas, or other types of fuels. The hybrid fuel combustion nozzle may include a natural gas system with a number of swozzle vanes and a syngas system with a number of co-annular fuel tubes.

  19. Dry low NOx combustion system with pre-mixed direct-injection secondary fuel nozzle

    Science.gov (United States)

    Zuo, Baifang; Johnson, Thomas; Ziminsky, Willy; Khan, Abdul

    2013-12-17

    A combustion system includes a first combustion chamber and a second combustion chamber. The second combustion chamber is positioned downstream of the first combustion chamber. The combustion system also includes a pre-mixed, direct-injection secondary fuel nozzle. The pre-mixed, direct-injection secondary fuel nozzle extends through the first combustion chamber into the second combustion chamber.

  20. SRB development motor (DM) 9 nozzle at Marshall Space Flight Center (MSFC)

    Science.gov (United States)

    1988-01-01

    Solid rocket booster (SRB) development motor (DM) 9 nozzle documentation shows the area where sections of the outer boot ring are missing. During a motor firing, the nozzle is subjected to temperatures reaching 5800 degrees fahrenheit (F). View provided by Marshall Space Flight Center (MSFC).

  1. High-Speed Additive Manufacturing Through High-Aspect-Ratio Nozzles

    Science.gov (United States)

    Shaw, Leon; Islam, Mashfiqul; Li, Jie; Li, Ling; Ayub, S. M. Imran

    2018-03-01

    The feasibility of layer-by-layer manufacturing through high-aspect-ratio (HAR) nozzles for microextrusion of paste to deposit planes has been investigated. Various conditions for paste extrusion, including nozzle moving speed, piston speed, extrusion rate, and distance between the nozzle tip and substrate, have been evaluated. By linking various microextrusion parameters together with the aid of a critical distance concept derived from microextrusion using circular nozzles and addressing the extrusion delay in response to the change of the piston speed and air pocket problems properly, we successfully microextruded single planes, multilayer objects, and larger planes made of multiple smaller planes side by side through HAR nozzles. It is further demonstrated that the X- Y dimensions of an extruded plane in the steady-state extrusion stage are determined by the nozzle travel distance and the length of the HAR nozzle opening if microextrusion is conducted with proper conditions. However, the height of the extruded plane is not only determined by the microextrusion conditions, but also affected by the drying shrinkage of the paste after microextrusion. This demonstration of the feasibility of using a HAR nozzle machine opens the door to manufacture of multimaterial, multilayer devices with high productivity in the near future.

  2. Early visual ERPs show stable body-sensitive patterns over a 4-week test period

    Science.gov (United States)

    Groves, Katie; Kennett, Steffan; Gillmeister, Helge

    2018-01-01

    Event-related potential (ERP) studies feature among the most cited papers in the field of body representation, with recent research highlighting the potential of ERPs as neuropsychiatric biomarkers. Despite this, investigation into how reliable early visual ERPs and body-sensitive effects are over time has been overlooked. This study therefore aimed to assess the stability of early body-sensitive effects and visual P1, N1 and VPP responses. Participants were asked to identify pictures of their own bodies, other bodies and houses during an EEG test session that was completed at the same time, once a week, for four consecutive weeks. Results showed that amplitude and latency of early visual components and their associated body-sensitive effects were stable over the 4-week period. Furthermore, correlational analyses revealed that VPP component amplitude might be more reliable than VPP latency and specific electrode sites might be more robust indicators of body-sensitive cortical activity than others. These findings suggest that visual P1, N1 and VPP responses, alongside body-sensitive N1/VPP effects, are robust indications of neuronal activity. We conclude that these components are eligible to be considered as electrophysiological biomarkers relevant to body representation. PMID:29438399

  3. Analysis of Daily Laboratory Orders at a Large Urban Academic Center: A Multifaceted Approach to Changing Test Ordering Patterns.

    Science.gov (United States)

    Rudolf, Joseph W; Dighe, Anand S; Coley, Christopher M; Kamis, Irina K; Wertheim, Bradley M; Wright, Douglas E; Lewandrowski, Kent B; Baron, Jason M

    2017-08-01

    We sought to address concerns regarding recurring inpatient laboratory test order practices (daily laboratory tests) through a multifaceted approach to changing ordering patterns. We engaged in an interdepartmental collaboration to foster mindful test ordering through clinical policy creation, electronic clinical decision support, and continuous auditing and feedback. Annualized daily order volumes decreased from approximately 25,000 to 10,000 during a 33-month postintervention review. This represented a significant change from preintervention order volumes (95% confidence interval, 0.61-0.64; P < 10-16). Total inpatient test volumes were not affected. Durable changes to inpatient order practices can be achieved through a collaborative approach to utilization management that includes shared responsibility for establishing clinical guidelines and electronic decision support. Our experience suggests auditing and continued feedback are additional crucial components to changing ordering behavior. Curtailing daily orders alone may not be a sufficient strategy to reduce in-laboratory costs. © American Society for Clinical Pathology, 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

  4. Bone cement penetration pattern and primary stability testing in keeled and pegged glenoid components.

    Science.gov (United States)

    Raiss, Patric; Pape, Guido; Kleinschmidt, Kerstin; Jäger, Sebastian; Sowa, Boris; Jakubowitz, Eike; Loew, Markus; Bruckner, Thomas; Rickert, Markus

    2011-07-01

    It has been proposed that bone mineral density has an influence on cement penetration in hip and knee arthroplasty. The hypotheses of this study were that: 1) there is a negative correlation between bone mineral density (BMD) and cement penetration in cemented glenoid components; and 2) that implant design has an influence on cement penetration into the glenoid bone. BMD of 10 pairs of fresh frozen scapulas was measured. Micro-computed tomography (micro-CT) scans in 3 different sections were analyzed after implantation of keeled and pegged glenoid components using a 3(rd)-generation cementing technique with a vacuum mixing system. Cement penetration was analyzed and correlated with BMD. Pull-out strength testing was performed to analyze primary stability. The overall peak BMD was 0.6 [g/cm(2)] (range, 0.33-0.98). A strong negative correlation between BMD and mean cement penetration was found for the peg (R(2) = -.83; P penetration was 78.4 mm(2) (range, 60.6-94.2) in the keel and 113.9 mm(2) (range, 78.2-143.4) in the peg group (P < .0001). In all cases, the components were pulled out of the cement mantle, whereas the bone-cement interfaces remained intact. The mean pull-out strength was 1093N (764-1343N) for keeled and 884N (650-1264N) for pegged components (P < .05). A modern cementing technique, leading to a deep bonding between bone and cement, is crucial to prevent loosening of glenoid components. The findings of this study might help us to better understand the results of follow-up studies of cemented glenoid implants. Our results could be helpful for the choice of implants in patients with poor bone quality like osteoporosis or rheumatoid arthritis. Copyright © 2011 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

  5. Technical Analysis of Kort Nozzle Application for SPOB Ship 4990 DWT on River

    Directory of Open Access Journals (Sweden)

    Tony Bambang Musriyadi

    2017-06-01

    Full Text Available Propeller is a locomotor shaped vanes are used to drive ships, and also propellers which serves to move tehaga by changing the turning force of the propeller thrust menggerakakan into the vessel. In increasing the value of the thrust to be generated that is by applying the kort nozzle propeller. The method used in this study using CFD (Computional Fluid Dynamic, and the variation is from the conventional propeller models, with a kort nozzle propeller type kort nozzle type 19A and 37. Based on the findings that the kort nozzle propeller with the addition of the value of the thrust , propeller efficiency and torque generated. The driving force value is by using kort nozzle propeller type 37 amounted to 349.27 kN.

  6. Computational Fluid Dynamics Modeling of a Supersonic Nozzle and Integration into a Variable Cycle Engine Model

    Science.gov (United States)

    Connolly, Joseph W.; Friedlander, David; Kopasakis, George

    2015-01-01

    This paper covers the development of an integrated nonlinear dynamic simulation for a variable cycle turbofan engine and nozzle that can be integrated with an overall vehicle Aero-Propulso-Servo-Elastic (APSE) model. A previously developed variable cycle turbofan engine model is used for this study and is enhanced here to include variable guide vanes allowing for operation across the supersonic flight regime. The primary focus of this study is to improve the fidelity of the model's thrust response by replacing the simple choked flow equation convergent-divergent nozzle model with a MacCormack method based quasi-1D model. The dynamic response of the nozzle model using the MacCormack method is verified by comparing it against a model of the nozzle using the conservation element/solution element method. A methodology is also presented for the integration of the MacCormack nozzle model with the variable cycle engine.

  7. Gas Nozzle Effect on the Deposition of Polysilicon by Monosilane Siemens Reactor

    Directory of Open Access Journals (Sweden)

    Seung Oh Kang

    2012-01-01

    Full Text Available Deposition of polysilicon (poly-Si was tried to increase productivity of poly-Si by using two different types of gas nozzle in a monosilane Bell-jar Siemens (MS-Siemens reactor. In a mass production of poly-Si, deposition rate and energy consumption are very important factors because they are main performance indicators of Siemens reactor and they are directly related with the production cost of poly-Si. Type A and B nozzles were used for investigating gas nozzle effect on the deposition of poly-Si in a MS-Siemens reactor. Nozzle design was analyzed by computation cluid dynamics (CFD. Deposition rate and energy consumption of poly-Si were increased when the type B nozzle was used. The highest deposition rate was 1 mm/h, and the lowest energy consumption was 72 kWh⋅kg-1 in this study.

  8. Navigation strategies as revealed by error patterns on the Magic Carpet test in children with cerebral palsy

    Directory of Open Access Journals (Sweden)

    Vittorio eBelmonti

    2015-07-01

    Full Text Available IntroductionShort-term memory develops differently in navigation vs. manual space. The Magic Carpet (MC is a novel navigation test derived from the Walking Corsi Test and the manual Corsi Block-tapping Task (CBT. The MC requires mental rotations and executive function. In Cerebral Palsy (CP, CBT and MC scores relate differently to clinical and lesional factors. Hypotheses of this study are: that frontal lesions specifically affect navigation in CP; that brain lesions affect MC cognitive strategies.Material and methodsTwenty-two children with spastic CP, aged 5 to 14 years, 14 with a unilateral and 8 with a bilateral form, underwent the CBT and the MC. Errors were classified into 7 patterns by a recently described algorithm. Brain lesions were quantified according to a novel semi-quantitative MRI scale. Control data were partially drawn from a previous study on 91 typically developing children.ResultsChildren with CP performed worse than controls on both tests. Right hemispheric impairment correlated with spatial memory. MC span was reduced less than CBT span and was more selectively related to right middle white-matter and frontal lesions. Error patterns were differently distributed in CP than in typical development and depended on right brain impairment: children with more extensive right lesions made more positional than sequential errors.DiscussionIn CP, navigation is affected only by extensive lesions involving the right frontal lobe. In addition, these are associated with abnormal cognitive strategies. Whereas in typical development positional errors, preserving serial order, increase with age and performance, in CP they are associated with poorer performance and more extensive right-brain lesions. The explanation may lie in lesion side: right brain is crucial for mental rotations, necessary for spatial updating. Left-lateralized spatial memory strategies, relying on serial order, are not efficient if not accompanied by right-brain spatial

  9. Application of shape-based similarity query for aerodynamic optimization of wind tunnel primary nozzle

    Directory of Open Access Journals (Sweden)

    Kolář Jan

    2012-04-01

    Full Text Available The aerodynamic shape optimization of the supersonic flat nozzle is the aim of proposed paper. The nozzle discussed, is applied as a primary nozzle of the inlet part of supersonic wind tunnel. Supersonic nozzles of the measure area inlet parts need to guarantee several requirements of flow properties and quality. Mach number and minimal differences between real and required velocity and turbulence profiles at the nozzle exit are the most important parameters to meet. The aerodynamic shape optimization of the flat 2D nozzle in CFD is employed to reach as uniform exit velocity profile as possible, with the mean Mach number 1.4. Optimization process does not use any of standard routines of global or local optimum searching. Instead, newly formed routine, which exploits shape-based oriented sequence of nozzles, is used to research within whole discretized parametric space. The movement within optimization process is not driven by gradient or evolutionary too, instead, the Path of Minimal Shape Deformation is followed. Dynamic mesh approach is used to deform the shape and mesh from the actual nozzle to the subsequent one. Dynamic deformation of mesh allows to speed up whole converging process as an initialization of flow at the newly formed mesh is based on afore-computed shape. Shape-based similarity query in field of supersonic nozzles is discussed and applied. Evolutionary technique with genetic algorithm is used to search for minimal deformational path. As a result, the best variant from the set of solved shapes is analyzed at the base of momentum coefficient and desired Mach number at the nozzle exit.

  10. Compressed air noise reductions from using advanced air gun nozzles in research and development environments.

    Science.gov (United States)

    Prieve, Kurt; Rice, Amanda; Raynor, Peter C

    2017-08-01

    The aims of this study were to evaluate sound levels produced by compressed air guns in research and development (R&D) environments, replace conventional air gun models with advanced noise-reducing air nozzles, and measure changes in sound levels to assess the effectiveness of the advanced nozzles as engineering controls for noise. Ten different R&D manufacturing areas that used compressed air guns were identified and included in the study. A-weighted sound level and Z-weighted octave band measurements were taken simultaneously using a single instrument. In each area, three sets of measurements, each lasting for 20 sec, were taken 1 m away and perpendicular to the air stream of the conventional air gun while a worker simulated typical air gun work use. Two different advanced noise-reducing air nozzles were then installed. Sound level and octave band data were collected for each of these nozzles using the same methods as for the original air guns. Both of the advanced nozzles provided sound level reductions of about 7 dBA, on average. The highest noise reductions measured were 17.2 dBA for one model and 17.7 dBA for the other. In two areas, the advanced nozzles yielded no sound level reduction, or they produced small increases in sound level. The octave band data showed strong similarities in sound level among all air gun nozzles within the 10-1,000 Hz frequency range. However, the advanced air nozzles generally had lower noise contributions in the 1,000-20,000 Hz range. The observed decreases at these higher frequencies caused the overall sound level reductions that were measured. Installing new advanced noise-reducing air nozzles can provide large sound level reductions in comparison to existing conventional nozzles, which has direct benefit for hearing conservation efforts.

  11. Thermal fatigue damage evaluation of a PWR NPP steam generator injection nozzle model subjected to thermal stratification phenomenon

    International Nuclear Information System (INIS)

    Leite da Silva, Luiz; Rodrigues Mansur, Tanius; Cimini Junior, Carlos Alberto

    2011-01-01

    Thermal stratification phenomenon with the same thermodynamic steam generator (SG) injection nozzle parameters was simulated. After 41 experiments, the experimental section was dismantled; cut and specimens were made of its material. Other specimens were made of the preserved pipe material. By comparing their fatigue tests results, the pipe material damage was evaluated. The water temperature layers and also the outside pipe wall temperatures were measured at the same level. Strains outside the pipe in 7 positions were measured. The experimental section develops thermal stratified flows, stresses and strains caused enlargement of material grain size and reduction in fatigue life.

  12. A Physical Model to Study the Effects of Nozzle Design on Dispersed Two-Phase Flows in a Slab Mold Casting Ultra-Low-Carbon Steels

    Science.gov (United States)

    Salazar-Campoy, María M.; Morales, R. D.; Nájera-Bastida, A.; Calderón-Ramos, Ismael; Cedillo-Hernández, Valentín; Delgado-Pureco, J. C.

    2018-02-01

    The effects of nozzle design on dispersed, two-phase flows of the steel-argon system in a slab mold are studied using a water-air model with particle image velocimetry and ultrasound probe velocimetry techniques. Three nozzle designs were tested with the same bore size and different port geometries, including square (S), special bottom design with square ports (U), and circular (C). The meniscus velocities of the liquid increase two- or threefold in two-phase flows regarding one-phase flows using low flow rates of the gas phase. This effect is due to the dragging effects on bubbles by the liquid jets forming two-way coupled flows. Liquid velocities (primary phase) along the narrow face of the mold also are higher for two-phase flows. Flows using nozzle U are less dependent on the effects of the secondary phase (air). The smallest bubble sizes are obtained using nozzle U, which confirms that bubble breakup is dependent on the strain rates of the fluid and dissipation of kinetic energy in the nozzle bottom and port edges. Through dimensionless analysis, it was found that the bubble sizes are inversely proportional to the dissipation rate of the turbulent kinetic energy, ɛ 0.4. A simple expression involving ɛ, surface tension, and density of metal is derived to scale up bubble sizes in water to bubble sizes in steel with different degrees of deoxidation. The validity of water-air models to study steel-argon flows is discussed. Prior works related with experiments to model argon bubbling in steel slab molds under nonwetting conditions are critically reviewed.

  13. SU-F-T-149: Development of the Monte Carlo Simulation Platform Using Geant4 for Designing Heavy Ion Therapy Beam Nozzle

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Jae-ik; Yoo, SeungHoon; Cho, Sungho; Ho Kim, Eun; Song, Yongkeun; Jung, Won-Gyun [Korea Institute of Radiological and Medical Science, Seoul, Seoul (Korea, Republic of)

    2016-06-15

    Purpose: The significant issue of particle therapy such as proton and carbon ion was a accurate dose delivery from beam line to patient. For designing the complex delivery system, Monte Carlo simulation can be used for the simulation of various physical interaction in scatters and filters. In this report, we present the development of Monte Carlo simulation platform to help design the prototype of particle therapy nozzle and performed the Monte Carlo simulation using Geant4. Also we show the prototype design of particle therapy beam nozzle for Korea Heavy Ion Medical Accelerator (KHIMA) project in Korea Institute of Radiological and Medical Science(KIRAMS) at Republic of Korea. Methods: We developed a simulation platform for particle therapy beam nozzle using Geant4. In this platform, the prototype nozzle design of Scanning system for carbon was simply designed. For comparison with theoretic beam optics, the beam profile on lateral distribution at isocenter is compared with Mont Carlo simulation result. From the result of this analysis, we can expected the beam spot property of KHIMA system and implement the spot size optimization for our spot scanning system. Results: For characteristics study of scanning system, various combination of the spot size from accerlator with ridge filter and beam monitor was tested as simple design for KHIMA dose delivery system. Conclusion: In this report, we presented the part of simulation platform and the characteristics study. This study is now on-going in order to develop the simulation platform including the beam nozzle and the dose verification tool with treatment planning system. This will be presented as soon as it is become available.

  14. A Physical Model to Study the Effects of Nozzle Design on Dispersed Two-Phase Flows in a Slab Mold Casting Ultra-Low-Carbon Steels

    Science.gov (United States)

    Salazar-Campoy, María M.; Morales, R. D.; Nájera-Bastida, A.; Calderón-Ramos, Ismael; Cedillo-Hernández, Valentín; Delgado-Pureco, J. C.

    2018-04-01

    The effects of nozzle design on dispersed, two-phase flows of the steel-argon system in a slab mold are studied using a water-air model with particle image velocimetry and ultrasound probe velocimetry techniques. Three nozzle designs were tested with the same bore size and different port geometries, including square (S), special bottom design with square ports (U), and circular (C). The meniscus velocities of the liquid increase two- or threefold in two-phase flows regarding one-phase flows using low flow rates of the gas phase. This effect is due to the dragging effects on bubbles by the liquid jets forming two-way coupled flows. Liquid velocities (primary phase) along the narrow face of the mold also are higher for two-phase flows. Flows using nozzle U are less dependent on the effects of the secondary phase (air). The smallest bubble sizes are obtained using nozzle U, which confirms that bubble breakup is dependent on the strain rates of the fluid and dissipation of kinetic energy in the nozzle bottom and port edges. Through dimensionless analysis, it was found that the bubble sizes are inversely proportional to the dissipation rate of the turbulent kinetic energy, ɛ 0.4. A simple expression involving ɛ, surface tension, and density of metal is derived to scale up bubble sizes in water to bubble sizes in steel with different degrees of deoxidation. The validity of water-air models to study steel-argon flows is discussed. Prior works related with experiments to model argon bubbling in steel slab molds under nonwetting conditions are critically reviewed.

  15. SU-F-T-149: Development of the Monte Carlo Simulation Platform Using Geant4 for Designing Heavy Ion Therapy Beam Nozzle

    International Nuclear Information System (INIS)

    Shin, Jae-ik; Yoo, SeungHoon; Cho, Sungho; Ho Kim, Eun; Song, Yongkeun; Jung, Won-Gyun

    2016-01-01

    Purpose: The significant issue of particle therapy such as proton and carbon ion was a accurate dose delivery from beam line to patient. For designing the complex delivery system, Monte Carlo simulation can be used for the simulation of various physical interaction in scatters and filters. In this report, we present the development of Monte Carlo simulation platform to help design the prototype of particle therapy nozzle and performed the Monte Carlo simulation using Geant4. Also we show the prototype design of particle therapy beam nozzle for Korea Heavy Ion Medical Accelerator (KHIMA) project in Korea Institute of Radiological and Medical Science(KIRAMS) at Republic of Korea. Methods: We developed a simulation platform for particle therapy beam nozzle using Geant4. In this platform, the prototype nozzle design of Scanning system for carbon was simply designed. For comparison with theoretic beam optics, the beam profile on lateral distribution at isocenter is compared with Mont Carlo simulation result. From the result of this analysis, we can expected the beam spot property of KHIMA system and implement the spot size optimization for our spot scanning system. Results: For characteristics study of scanning system, various combination of the spot size from accerlator with ridge filter and beam monitor was tested as simple design for KHIMA dose delivery system. Conclusion: In this report, we presented the part of simulation platform and the characteristics study. This study is now on-going in order to develop the simulation platform including the beam nozzle and the dose verification tool with treatment planning system. This will be presented as soon as it is become available.

  16. 49 CFR 179.200-13 - Manway ring or flange, pressure relief device flange, bottom outlet nozzle flange, bottom washout...

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Manway ring or flange, pressure relief device flange, bottom outlet nozzle flange, bottom washout nozzle flange and other attachments and openings. 179....200-13 Manway ring or flange, pressure relief device flange, bottom outlet nozzle flange, bottom...

  17. EXAMPLE OF FLOW MODELLING CHARACTERISTICS IN DIESEL ENGINE NOZZLE

    Directory of Open Access Journals (Sweden)

    Dušan KOLARIČ

    2016-03-01

    Full Text Available Modern transport is still based on vehicles powered by internal combustion engines. Due to stricter ecological requirements, the designers of engines are continually challenged to develop more environmentally friendly engines with the same power and performance. Unfortunately, there are not any significant novelties and innovations available at present which could significantly change the current direction of the development of this type of propulsion machines. That is why the existing ones should be continually developed and improved or optimized their performance. By optimizing, we tend to minimize fuel consumption and lower exhaust emissions in order to meet the norms defined by standards (i.e. Euro standards. Those propulsion engines are actually developed to such extent that our current thinking will not be able to change their basic functionality, but possible opportunities for improvement, especially the improvement of individual components, could be introduced. The latter is possible by computational fluid dynamics (CFD which can relatively quickly and inexpensively produce calculations prior to prototyping and implementation of accurate measurements on the prototype. This is especially useful in early stages of development or at optimization of dimensional small parts of the object where the physical execution of measurements is impossible or very difficult. With advances of computational fluid dynamics, the studies on the nozzles and outlet channel injectors have been relieved. Recently, the observation and better understanding of the flow in nozzles at large pressure and high velocity is recently being possible. This is very important because the injection process, especially the dispersion of jet fuel, is crucial for the combustion process in the cylinder and consequently for the composition of exhaust gases. And finally, the chemical composition of the fuel has a strong impact on the formation of dangerous emissions, too. The

  18. Typhoid outbreak in Songkhla, Thailand 2009-2011: clinical outcomes, susceptibility patterns, and reliability of serology tests.

    Directory of Open Access Journals (Sweden)

    Wannee Limpitikul

    Full Text Available OBJECTIVE: To determine the clinical manifestations and outcomes, the reliability of Salmonella enterica serotype Typhi (S ser. Typhi IgM and IgG rapid tests, and the susceptibility patterns and the response to treatment during the 2009-2011 typhoid outbreak in Songkhla province in Thailand. METHOD: The medical records of children aged <15 years with S ser. Typhi bacteremia were analysed. The efficacy of the typhoid IgM and IgG rapid tests and susceptibility of the S ser. Typhi to the current main antibiotics used for typhoid (amoxicillin, ampicillin, cefotaxime, ceftriaxone, co-trimoxazole, and ciprofloxacin, were evaluated. RESULTS: S ser. Typhi bacteremia was found in 368 patients, and all isolated strains were susceptible to all 6 antimicrobials tested. Most of the patients were treated with ciprofloxacin for 7-14 days. The median time (IQR of fever before treatment and duration of fever after treatment were 5 (4, 7 days and 4 (3, 5 days, respectively. Complications of ascites, lower respiratory symptoms, anemia (Hct <30%, and ileal perforation were found in 7, 7, 22, and 1 patients, respectively. None of the patients had recurrent infection or died. The sensitivities of the typhoid IgM and IgG tests were 58.3% and 25.6% respectively, and specificities were 74.1% and 50.5%, respectively. CONCLUSION: Most of the patients were diagnosed at an early stage and treated with a good outcome. All S ser. Typhi strains were susceptible to standard first line antibiotic typhoid treatment. The typhoid IgM and IgG rapid tests had low sensitivity and moderate specificity.

  19. Testing promotes long-term learning via stabilizing activation patterns in a large network of brain areas.

    Science.gov (United States)

    Keresztes, Attila; Kaiser, Daniel; Kovács, Gyula; Racsmány, Mihály

    2014-11-01

    The testing effect refers to the phenomenon that repeated retrieval of memories promotes better long-term retention than repeated study. To investigate the neural correlates of the testing effect, we used event-related functional magnetic resonance imaging methods while participants performed a cued recall task. Prior to the neuroimaging experiment, participants learned Swahili-German word pairs, then half of the word pairs were repeatedly studied, whereas the other half were repeatedly tested. For half of the participants, the neuroimaging experiment was performed immediately after the learning phase; a 1-week retention interval was inserted for the other half of the participants. We found that a large network of areas identified in a separate 2-back functional localizer scan were active during the final recall of the word pair associations. Importantly, the learning strategy (retest or restudy) of the word pairs determined the manner in which the retention interval affected the activations within this network. Recall of previously restudied memories was accompanied by reduced activation within this network at long retention intervals, but no reduction was observed for previously retested memories. We suggest that retrieval promotes learning via stabilizing cue-related activation patterns in a network of areas usually associated with cognitive and attentional control functions. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  20. A visual study of forced convection boiling. Part 2: Flow patterns and burnout for a round test section

    International Nuclear Information System (INIS)

    Kirby, G.J.; Staniforth, R.; Kinneir, J.H.

    1967-03-01

    The studies of boiling water at 25 p.s.i.a. reported here show the same flow patterns as in earlier tests in that the bubbles formed on the heater regained close to the heated surface to coalesce into large bubbles which eventually spanned the flow channel. Burnout tests were made and it was found there was a change of slope of the heat flux-subcooling curve. Further tests showed that this effect was due to a change in flow regime between burnout with much vapour present and burnout with just nucleate bubbles present. In the latter regime it was found that burnout is dependent only on the conditions local to the burnout point. Photography of the burnout region was practicable only when few bubbles were present but although pictures of the bubble over the burnout point were taken, no clear evidence on the mechanism of formation of the bubble could be gleaned. Some speculation on the cause of burnout in this regime is made in the light of these experiments. (author)

  1. Genetic testing behavior and reporting patterns in electronic medical records for physicians trained in a primary care specialty or subspecialty.

    Science.gov (United States)

    Ronquillo, Jeremiah Geronimo; Li, Cheng; Lester, William T

    2012-01-01

    To characterize important patterns of genetic testing behavior and reporting in modern electronic medical records (EMRs) at the institutional level. Retrospective observational study using EMR data of all 10,715 patients who received genetic testing by physicians trained in a primary care specialty or subspecialty at an academic medical center between January 1, 2008 and December 31, 2010. Patients had a mean±SD age of 38.3±15.8 years (median 36.1, IQR 30.0-43.8). The proportion of female subjects in the study population was larger than in the general patient population (77.2% vs 55.0%, pTay-Sachs disease (6.7%), hereditary hemochromatosis (4.4%), and chronic myelogenous leukemia (4.1%). EMRs stored reports as free text with categorical descriptions of mutations and an average length of 269.4±153.2 words (median 242, IQR 146-401). In this study, genetic tests were often ordered by a diverse group of physicians for women of childbearing age being evaluated for diseases that may affect potential offspring. EMRs currently serve primarily as a storage warehouse for textual reports that could potentially be transformed into meaningful structured data for next-generation clinical decision support. Further studies are needed to address the design, development, and implementation of EMRs capable of managing the critical genetic health information challenges of the future.

  2. An experimental test of well-described vegetation patterns across slope aspects using woodland herb transplants and manipulated abiotic drivers.

    Science.gov (United States)

    Warren, Robert J

    2010-03-01

    *The ubiquitous transition of plant communities across slope aspects is a well-described, but rarely tested, ecological dynamic. Aspect position is often used as a proxy for microclimate changes in moisture, light and temperature, but these abiotic drivers are seldom decoupled and very rarely manipulated across slope aspects. *To investigate the mechanisms and demographic stages driving the observed distribution patterns of two woodland herbs in the southeastern USA, seeds and adults were transplanted across north- and south-facing slopes, and moisture and light were experimentally manipulated. *Stage- and species-specific abiotic responses resulted in similar landscape-level patterning for Hexastylis arifolia and Hepatica nobilis, but the underlying abiotic drivers were unique. Adult rather than seed survival best explained the natural distributions across slope aspects, and Hexastylis arifolia was limited by higher temperature, whereas Hepatica nobilis was limited by lower soil moisture. *The stage- and species-specific responses indicated that the use of slope aspect to explain plant distributions not only obfuscates explanatory mechanisms, but probably undermines the portability of results. As abiotic drivers, not topographical proxies, are projected to shift with global climate change, distribution research requires direct abiotic data in association with key demographic stages rather than topographical proxies.

  3. An unsupervised pattern recognition approach for AE data originating from fatigue tests on polymer-composite materials

    Science.gov (United States)

    Doan, D. D.; Ramasso, E.; Placet, V.; Zhang, S.; Boubakar, L.; Zerhouni, N.

    2015-12-01

    This work investigates acoustic emission generated during tension fatigue tests carried out on a carbon fiber reinforced polymer (CFRP) composite specimen. Since massive fatigue data processing, especially noise reduction, remains an important challenge in AE data analysis, a Mahalanobis distance-based noise modeling has been proposed in the present work to tackle this problem. A sequential feature selection based on Davies-Bouldin index has been implemented for fast dimensionality reduction. An unsupervised classifier offline-learned from quasi-static data is then used to classify the data to different AE sources with the possibility to dynamically accommodate with unseen ones. With an efficient proposed noise removal and automatic separation of AE events, this pattern discovery procedure provides an insight into fatigue damage development in composites in the presence of millions of AE events.

  4. Computer Graphic Design Using Auto-CAD and Plug Nozzle Research

    Science.gov (United States)

    Rogers, Rayna C.

    2004-01-01

    The purpose of creating computer generated images varies widely. They can be use for computational fluid dynamics (CFD), or as a blueprint for designing parts. The schematic that I will be working on the summer will be used to create nozzles that are a part of a larger system. At this phase in the project, the nozzles needed for the systems have been fabricated. One part of my mission is to create both three dimensional and two dimensional models on Auto-CAD 2002 of the nozzles. The research on plug nozzles will allow me to have a better understanding of how they assist in the thrust need for a missile to take off. NASA and the United States military are working together to develop a new design concept. On most missiles a convergent-divergent nozzle is used to create thrust. However, the two are looking into different concepts for the nozzle. The standard convergent-divergent nozzle forces a mixture of combustible fluids and air through a smaller area in comparison to where the combination was mixed. Once it passes through the smaller area known as A8 it comes out the end of the nozzle which is larger the first or area A9. This creates enough thrust for the mechanism whether it is an F-18 fighter jet or a missile. The A9 section of the convergent-divergent nozzle has a mechanism that controls how large A9 can be. This is needed because the pressure of the air coming out nozzle must be equal to that of the ambient pressure other wise there will be a loss of performance in the machine. The plug nozzle however does not need to have an A9 that can vary. When the air flow comes out it can automatically sense what the ambient pressure is and will adjust accordingly. The objective of this design is to create a plug nozzle that is not as complicated mechanically as it counterpart the convergent-divergent nozzle.

  5. Additional Stress And Fracture Mechanics Analyses Of Pressurized Water Reactor Pressure Vessel Nozzles

    International Nuclear Information System (INIS)

    Walter, Matthew; Yin, Shengjun; Stevens, Gary; Sommerville, Daniel; Palm, Nathan; Heinecke, Carol

    2012-01-01

    In past years, the authors have undertaken various studies of nozzles in both boiling water reactors (BWRs) and pressurized water reactors (PWRs) located in the reactor pressure vessel (RPV) adjacent to the core beltline region. Those studies described stress and fracture mechanics analyses performed to assess various RPV nozzle geometries, which were selected based on their proximity to the core beltline region, i.e., those nozzle configurations that are located close enough to the core region such that they may receive sufficient fluence prior to end-of-life (EOL) to require evaluation of embrittlement as part of the RPV analyses associated with pressure-temperature (P-T) limits. In this paper, additional stress and fracture analyses are summarized that were performed for additional PWR nozzles with the following objectives: To expand the population of PWR nozzle configurations evaluated, which was limited in the previous work to just two nozzles (one inlet and one outlet nozzle). To model and understand differences in stress results obtained for an internal pressure load case using a two-dimensional (2-D) axi-symmetric finite element model (FEM) vs. a three-dimensional (3-D) FEM for these PWR nozzles. In particular, the ovalization (stress concentration) effect of two intersecting cylinders, which is typical of RPV nozzle configurations, was investigated. To investigate the applicability of previously recommended linear elastic fracture mechanics (LEFM) hand solutions for calculating the Mode I stress intensity factor for a postulated nozzle corner crack for pressure loading for these PWR nozzles. These analyses were performed to further expand earlier work completed to support potential revision and refinement of Title 10 to the U.S. Code of Federal Regulations (CFR), Part 50, Appendix G, Fracture Toughness Requirements, and are intended to supplement similar evaluation of nozzles presented at the 2008, 2009, and 2011 Pressure Vessels and Piping (PVP

  6. Adiabatic Expansion of Electron Gas in a Magnetic Nozzle

    Science.gov (United States)

    Takahashi, Kazunori; Charles, Christine; Boswell, Rod; Ando, Akira

    2018-01-01

    A specially constructed experiment shows the near perfect adiabatic expansion of an ideal electron gas resulting in a polytropic index greater than 1.4, approaching the adiabatic value of 5 /3 , when removing electric fields from the system, while the polytropic index close to unity is observed when the electrons are trapped by the electric fields. The measurements were made on collisionless electrons in an argon plasma expanding in a magnetic nozzle. The collision lengths of all electron collision processes are greater than the scale length of the expansion, meaning the system cannot be in thermodynamic equilibrium, yet thermodynamic concepts can be used, with caution, in explaining the results. In particular, a Lorentz force, created by inhomogeneities in the radial plasma density, does work on the expanding magnetic field, reducing the internal energy of the electron gas that behaves as an adiabatically expanding ideal gas.

  7. Fuel injection nozzle and method of manufacturing the same

    Science.gov (United States)

    Monaghan, James Christopher; Johnson, Thomas Edward; Ostebee, Heath Michael

    2017-02-21

    A fuel injection head for use in a fuel injection nozzle comprises a monolithic body portion comprising an upstream face, an opposite downstream face, and a peripheral wall extending therebetween. A plurality of pre-mix tubes are integrally formed with and extend axially through the body portion. Each of the pre-mix tubes comprises an inlet adjacent the upstream face, an outlet adjacent the downstream face, and a channel extending between the inlet and the outlet. Each pre-mix tube also includes at least one fuel injector that at least partially extends outward from an exterior surface of the pre-mix tube, wherein the fuel injector is integrally formed with the pre-mix tube and is configured to facilitate fuel flow between the body portion and the channel.

  8. Evaluation of dual flow thrust vectored nozzles with exhaust stream impingement. MS Thesis Final Technical Report, Oct. 1990 - Jul. 1991

    Science.gov (United States)

    Carpenter, Thomas W.

    1991-01-01

    The main objective of this project was to predict the expansion wave/oblique shock wave structure in an under-expanded jet expanding from a convergent nozzle. The shock structure was predicted by combining the calculated curvature of the free pressure boundary with principles and governing equations relating to oblique shock wave and expansion wave interaction. The procedure was then continued until the shock pattern repeated itself. A mathematical model was then formulated and written in FORTRAN to calculate the oblique shock/expansion wave structure within the jet. In order to study shock waves in expanding jets, Schlieren photography, a form of flow visualization, was employed. Thirty-six Schlieren photographs of jets from both a straight and 15 degree nozzle were taken. An iterative procedure was developed to calculate the shock structure within the jet and predict the non-dimensional values of Prandtl primary wavelength (w/rn), distance to Mach Disc (Ld) and Mach Disc radius (rd). These values were then compared to measurements taken from Schlieren photographs and experimental results. The results agreed closely to measurements from Schlieren photographs and previously obtained data. This method provides excellent results for pressure ratios below that at which a Mach Disc first forms. Calculated values of non-dimensional distance to the Mach Disc (Ld) agreed closely to values measured from Schlieren photographs and published data. The calculated values of non-dimensional Mach Disc radius (rd), however, deviated from published data by as much as 25 percent at certain pressure ratios.

  9. Phased Array Noise Source Localization Measurements of an F404 Nozzle Plume at Both Full and Model Scale

    Science.gov (United States)

    Podboy, Gary G.; Bridges, James E.; Henderson, Brenda S.

    2010-01-01

    A 48-microphone planar phased array system was used to acquire jet noise source localization data on both a full-scale F404-GE-F400 engine and on a 1/4th scale model of a F400 series nozzle. The full-scale engine test data show the location of the dominant noise sources in the jet plume as a function of frequency for the engine in both baseline (no chevron) and chevron configurations. Data are presented for the engine operating both with and without afterburners. Based on lessons learned during this test, a set of recommendations are provided regarding how the phased array measurement system could be modified in order to obtain more useful acoustic source localization data on high-performance military engines in the future. The data obtained on the 1/4th scale F400 series nozzle provide useful insights regarding the full-scale engine jet noise source mechanisms, and document some of the differences associated with testing at model-scale versus fullscale.

  10. Conception and realization of optical diagnosis to characterize gas puffs in Z-Pinch experiments. Comparison between experiment and computation. Study of a new nozzle

    International Nuclear Information System (INIS)

    Barnier, J.N.

    1998-01-01

    The CEA develops research programs on plasma. A good way to generate such X-rays sources, is to realize Z-pinch experiments, so to realize the radial implosion on its axis of a conducting cylinder in a very high current. The AMBIORIX machine, allowing such experiments, calls for necessitates the use of gaseous conductors. The gas puff, coming from the nozzle, is ionised by a 2 MA current. The aim of this thesis is the characterisation of the gas source before the current impulse. For this purpose many optic diagnostics have been tested. Interferometric measures allow the gas profile density measurement. Various gas have been studied: neon, argon, helium and aluminium. For the aluminium, the resonant interferometric imagery method has been used. A new nozzle with an innovative injection technic, has been designed, characterized and tested in Z-pinch configuration. Finally measures of light diffusion (Rayleigh) have been realised to show dust in the gas. (A.L.B.)

  11. Pengaruh Variasi Lip Thickness pada Nozzle Terpancung terhadap Karakteristik Api Pembakaran Difusi Concentric Jet Flow

    Directory of Open Access Journals (Sweden)

    Elka Faizal

    2016-05-01

    Full Text Available Nozzle shape greatly influence turbulence between the fuel, air and formation of flow recirculation zone to produce a homogeneous mixing and get a near-perfect combustion. The recirculation zone is area that caused by flow rate breakdown, causing vortex and backflow around the end of nozzle. This backflow that hold up while lowering the flame so the flow rate of fuel and air mixture maintained lower or equal with flame speed. This study used variation of lip thickness of truncated nozzle 0, 4, 8, 12, and 16 mm.To obtain flame stability, fuel velocity and air velocity were variated. Thermocouples were used to measure flame temperature and its distribution. The results showed that stability of concentric jet diffusion flame flow increased with narrow lip thickness on a truncated nozzle. The wider stability area obtained in 4 mm lip thickness. In addition, temperature on diffusion flames concentric jet flow also more evenly distributed evenly with size of the nozzle lip thickness. The highest temperature and temperature distribution in the horizontal direction were occured in in the nozzle with lip thickness of 0 mm. A shadowgrapgh visualization was also used to identify phenomena of the nozzle exit flow.

  12. Evaluation of flip-flop jet nozzles for use as practical excitation devices

    Science.gov (United States)

    Raman, Ganesh; Rice, Edward J.; Cornelius, David M.

    1994-01-01

    This paper describes the flowfield characteristics of the flip-flop jet nozzle and the potential for using this nozzle as a practical excitation device. It appears from the existing body of published information that there is a lack of data on the parameters affecting the operation of such nozzles and on the mechanism of operation of these nozzles. An attempt is made in the present work to study the important parameters affecting the operation and performance of a flip-flop jet nozzle. Measurements were carried out to systematically assess the effect of varying the nozzle pressure ratio (NPR) as well as the length and volume of the feedback tube on the frequency of oscillation of this device. Flow visualization was used to obtain a better understanding of the jet flowfield and of the processes occurring within the feedback tube. The frequency of oscillation of the flip-flop jet depended significantly on the feedback tube length and volume as well as on the nozzle pressure ratio. In contrast, the coherent velocity perturbation levels did not depend on the above mentioned parameters. The data presented in this paper would be useful for modeling such flip-flop excitation devices that are potentially useful for controlling practical shear flows.

  13. Laminar and turbulent nozzle-jet flows and their acoustic near-field

    International Nuclear Information System (INIS)

    Bühler, Stefan; Obrist, Dominik; Kleiser, Leonhard

    2014-01-01

    We investigate numerically the effects of nozzle-exit flow conditions on the jet-flow development and the near-field sound at a diameter-based Reynolds number of Re D = 18 100 and Mach number Ma = 0.9. Our computational setup features the inclusion of a cylindrical nozzle which allows to establish a physical nozzle-exit flow and therefore well-defined initial jet-flow conditions. Within the nozzle, the flow is modeled by a potential flow core and a laminar, transitional, or developing turbulent boundary layer. The goal is to document and to compare the effects of the different jet inflows on the jet flow development and the sound radiation. For laminar and transitional boundary layers, transition to turbulence in the jet shear layer is governed by the development of Kelvin-Helmholtz instabilities. With the turbulent nozzle boundary layer, the jet flow development is characterized by a rapid changeover to a turbulent free shear layer within about one nozzle diameter. Sound pressure levels are strongly enhanced for laminar and transitional exit conditions compared to the turbulent case. However, a frequency and frequency-wavenumber analysis of the near-field pressure indicates that the dominant sound radiation characteristics remain largely unaffected. By applying a recently developed scaling procedure, we obtain a close match of the scaled near-field sound spectra for all nozzle-exit turbulence levels and also a reasonable agreement with experimental far-field data

  14. Experimental investigation on heat transfer from square jets issuing from perforated nozzles

    Science.gov (United States)

    Muvvala, Pullarao; Balaji, C.; Venkateshan, S. P.

    2017-07-01

    This paper reports the results of an experimental investigation of fluid flow and heat transfer carried out with square jets issuing from perforated nozzles. This is accomplished by an impinging square jet on a uniformly heated plate of finite thickness (5 mm). The medium under consideration is air. Three different nozzle configurations are used in the study namely a single nozzle and perforated nozzles with four and nine holes, which are accommodated in the same available jet area 4.6 mm × 4.6 mm. This arrangement is akin to introducing a wire mesh at the nozzle exit plane. The effects of dimensionless jet-to-plate distance (2-9) and the mass flow rate of the jet fluid on the heat transfer rate are studied. Jet centerline mean velocity and turbulence intensity measurements are made with a hot-wire anemometer. The pressure drop across the orifice nozzle plate is measured and corresponding pumping power values are calculated. A comparison of the heat transfer performance and pumping power penalty of the three nozzle configurations is done.

  15. Design of a three-dimensional scramjet nozzle considering lateral expansion and geometric constraints

    Science.gov (United States)

    Lv, Zheng; Xu, Jinglei; Mo, Jianwei

    2017-12-01

    A new method based on quasi two-dimensional supersonic flow and maximum thrust theory to design a three-dimensional nozzle while considering lateral expansion and geometric constraints is presented in this paper. To generate the configuration of the three-dimensional nozzle, the inviscid flowfield is calculated through the method of characteristics, and the reference temperature method is applied to correct the boundary layer thickness. The computational fluid dynamics approach is used to obtain the aerodynamic performance of the nozzle. Results show that the initial arc radius slightly influences the axial thrust coefficient, whereas the variations in the lateral expansion contour, the length and initial expansion angle of the lower cowl significantly affect the axial thrust coefficient. The three-dimensional nozzle designed by streamline tracing technique is also investigated for comparison to verify the superiority of the new method. The proposed nozzle shows increases in the axial thrust coefficient, lift, and pitching moment of 6.86%, 203.15%, and 642.86%, respectively, at the design point, compared with the nozzle designed by streamline tracing approach. In addition, the lateral expansion accounts for 22.46% of the entire axial thrust, while it has no contribution to the lift and pitching moment in the proposed nozzle.

  16. Battery lifetime prediction by pattern recognition. Application to lead-acid battery life-cycling test data

    Science.gov (United States)

    Perone, Sam P.; Spindler, W. C.

    1984-09-01

    A novel approach to battery lifetime prediction has been evaluated by application to life-cycling data collected for 108 ESB EV-106 6-V. golf cart batteries (tests conducted by TRW for NASA-Lewis). This approach utilized computerized pattern recognition methods to examine initial cycling measurements and classify each battery into one of two classes: "long-lived" or "short-lived". The classifier program was based on either a linear discriminant or nearest neighbor analysis of a training set consisting of: each member of the EV battery set which had failed; the relative lifetime of each member — normalized with respect to test conditions; and a set of "features" based on measurements of the initial behavior. The raw data set included capacity trends over the first 8 or 9 cycles and records of specific gravity and water-added for each cell after initial cycling. Features defined from these raw data included the individual data items as well as transformations and combinations of these data. All features were represented as standardized variables. It was shown that lifetime prediction of batteries within the two categories defined could be made with about 87% accuracy. It is concluded that for a similarly-manufactured battery set, relative lifetime prediction could be based on initial measurements of the same type examined here.

  17. Slot Nozzle Effects for Reduced Sonic Boom on a Generic Supersonic Wing Section

    Science.gov (United States)

    Caster, Raymond S.

    2010-01-01

    NASA has conducted research programs to reduce or eliminate the operational restrictions of supersonic aircraft over populated areas. Restrictions are due to the disturbance from the sonic boom, caused by the coalescence of shock waves formed off the aircraft. Results from two-dimensional computational fluid dynamic (CFD) analyses (performed on a baseline Mach 2.0 nozzle in a simulated Mach 2.2 flow) indicate that over-expanded and under-expanded operation of the nozzle has an effect on the N-wave boom signature. Analyses demonstrate the feasibility of reducing the magnitude of the sonic boom N-wave by controlling the nozzle plume interaction with the nozzle boat tail shock structure. This work was extended to study the impact of integrating a high aspect ratio exhaust nozzle or long slot nozzle on the trailing edge of a supersonic wing. The nozzle is operated in a highly under-expanded condition, creating a large exhaust plume and a shock at the trailing edge of the wing. This shock interacts with and suppresses the expansion wave caused by the wing, a major contributor to the sonic boom signature. The goal was to reduce the near field pressures caused by the expansion using a slot nozzle located at the wing trailing edge. Results from CFD analysis on a simulated wing cross-section and a slot nozzle indicate potential reductions in sonic boom signature compared to a baseline wing with no propulsion or trailing edge exhaust. Future studies could investigate if this effect could be useful on a supersonic aircraft for main propulsion, auxiliary propulsion, or flow control.

  18. Timing of tensor and levator veli palatini force application determines eustachian tube resistance patterns during the forced-response test.

    Science.gov (United States)

    Ghadiali, Samir N; Bell, E David; Swarts, J Douglas

    2010-12-01

    The forced-response test (FRT) is used to assess eustachian tube (ET) function in patients with middle ear disease (otitis media). This test often documents a dynamic pattern of luminal dilation and constriction during swallowing which can be quantified as a function relating active tubal resistance with time. The goal of this study is to use a generalized finite element model (FEM) to test the hypothesis that the relative timing of muscle force application by the tensor veli palatini muscle (mTVP) and levator veli palatini muscle (mLVP) on the ET determines the form of active resistance functions. Seven resistance waveforms were obtained during the FRT in five adult subjects. A 2D FEM of the ET was constructed from an adult histological specimen and viscoelastic tissue mechanical properties were specified based on measurements obtained in each subject. Least-squared regression routines were used to vary the timing and magnitude of mTVP and mLVP force applications to the ET in order to match the active resistance functions recorded during the FRT. Variation of muscle force timing and magnitude in the FEM simulations reproduced the seven active resistance waveforms with high fidelity. Early application of mTVP force in combination with mLVP force produced a waveform characterized by an initial dilation (low resistances) followed by lumen constriction (higher resistances), while delayed mTVP force application caused an initial lumen constriction followed by dilation. These results indicate that the active resistance waveforms observed during the FRT reflect differences in the temporal pattern of mLVP and mTVP force application to the ET and emphasize that, like the mTVP, the mLVP functionally interacts with the ET. Results also indicate that in normal adults contraction of the mLVP promotes lumen constriction and that the initial lumen constriction is highly sensitive to the relative delay timing of mTVP and mLVP force application. Copyright (c) 2010 Elsevier Ireland

  19. Base Flow and Heat Transfer Characteristics of a Four-Nozzle Clustered Rocket Engine: Effect of Nozzle Pressure Ratio

    Science.gov (United States)

    Nallasamy, R.; Kandula, M.; Duncil, L.; Schallhorn, P.

    2010-01-01

    The base pressure and heating characteristics of a four-nozzle clustered rocket configuration is studied numerically with the aid of OVERFLOW Navier-Stokes code. A pressure ratio (chamber pressure to freestream static pressure) range of 990 to 5,920 and a freestream Mach number range of 2.5 to 3.5 are studied. The qualitative trends of decreasing base pressure with increasing pressure ratio and increasing base heat flux with increasing pressure ratio are correctly predicted. However, the predictions for base pressure and base heat flux show deviations from the wind tunnel data. The differences in absolute values between the computation and the data are attributed to factors such as perfect gas (thermally and calorically perfect) assumption, turbulence model inaccuracies in the simulation, and lack of grid adaptation.

  20. Device for detecting the water leak within a feedwater nozzle in water cooled reactors

    International Nuclear Information System (INIS)

    Hattori, Tsunekazu.

    1984-01-01

    Purpose: To enable exact recognition and detection for the state of water leak. Constitution: The detection device comprises a thermocouple disposed to the outer surface of a feedwater nozzle, a distortion meter for detecting the change in the outer diameter of a nozzle and an acoustic emission generator disposed to the inside of the nozzle for generating a signal upon temperature change. These sensors previously monitor the states during normal operation, and thus detect the change in each of the states upon occurrence of water leakage to issue an alarm. (Kamimura, M.)

  1. Determination of two dimensional axisymmetric finite element model for reactor coolant piping nozzles

    International Nuclear Information System (INIS)

    Choi, S. N.; Kim, H. N.; Jang, K. S.; Kim, H. J.

    2000-01-01

    The purpose of this paper is to determine a two dimensional axisymmetric model through a comparative study between a three dimensional and an axisymmetric finite element analysis of the reactor coolant piping nozzle subject to internal pressure. The finite element analysis results show that the stress adopting the axisymmetric model with the radius of equivalent spherical vessel are well agree with that adopting the three dimensional model. The radii of equivalent spherical vessel are 3.5 times and 7.3 times of the radius of the reactor coolant piping for the safety injection nozzle and for the residual heat removal nozzle, respectively

  2. Welding residual stress distributions for dissimilar metal nozzle butt welds in pressurized water reactors

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ji Soo; Kim, Ju Hee; Bae, Hong Yeol; OH, Chang Young; Kim, Yun Jae [Korea Univ., Seoul (Korea, Republic of); Lee, Kyungsoo [Korea Electric Power Research Institute, Daejeon (Korea, Republic of); Song, Tae Kwang [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2012-02-15

    In pressurized water nuclear reactors, dissimilar metal welds are susceptible to primary water stress corrosion cracking. To access this problem, accurate estimation of welding residual stresses is important. This paper provides general welding residual stress profiles in dissimilar metal nozzle butt welds using finite element analysis. By introducing a simplified shape for dissimilar metal nozzle butt welds, changes in the welding residual stress distribution can be seen using a geometry variable. Based on the results, a welding residual stress profile for dissimilar metal nozzle butt welds is proposed that modifies the existing welding residual stress profile for austenitic pipe butt welds.

  3. Understanding of cluster size deviation by measuring the dimensions of cluster jet from conical nozzles

    Directory of Open Access Journals (Sweden)

    Guanglong Chen

    2013-03-01

    Full Text Available This work aims to understand the cluster size deviation from the prediction by an existing scaling law for conical nozzles. The dimensions of cluster jet at different heights above a nozzle along the direction of gas flow are measured. This study indicates that the dimension of cluster jet is underestimated in the existing scaling law and this under-estimation leads to the over-estimation of the equivalent diameter of conical nozzle. Thus the underestimation of the dimension of cluster jet may be one of possible factors responsible for the cluster size deviation (the degree of the deviation depends on details of cluster jet.

  4. Development of Weld Overlay Technology for Dissimilar Welds in Pressurizer Nozzles

    Energy Technology Data Exchange (ETDEWEB)

    Park, K. S.; Byeon, J. G.; Lee, J. B. [Doosan Heavy Industries and Construction Co., Daejeon (Korea, Republic of)

    2009-10-15

    As a result of Primary Water Stress Corrosion Cracking (PWSCC) in alloy 600, leaks in dissimilar metal welds of pressurizer nozzles were discovered recently in several US plants. The involved companies developed advanced repair techniques to prevent or repair PWSCC applying weld overlay procedures to dissimilar metal welds such as those between pipes and nozzles. Within 2 or 3 years, more than half of the nuclear power plants in Korea will have been in operation for more than 20 years. From this background, a weld overlay procedure has been developed in Korea for the dissimilar metal welds of pressurizer nozzles.

  5. Thermal-hydraulics of PGV-4 water volume during damage of the feedwater collector nozzles

    Energy Technology Data Exchange (ETDEWEB)

    Logvinov, S.A.; Titov, V.F. [OKB Gidropress (Russian Federation); Notaros, U.; Lenkei, I. [NPP Paks (Hungary)

    1995-12-31

    A number of VVER-440 plants has experienced the distributing nozzles of feedwater collector being damaged due to corrosion-erosion wearing. Such phenomenon could result in feedwater redistribution within the SG inventory with undesirable consequences. The collector with damaged nozzles has to be replaced but a certain time is needed for the preparatory works. The main objective of the investigation conducted is to assess if the safe operation of SG is possible before collector replacement. It was shown that the nozzle damage as observed did not result in the dangerous disturbances of thermobydraulics as compared with the conditions existing at the initial period of operation. (orig.).

  6. How Are Fishing Patterns and Fishing Communities Responding to Climate Change? A Test Case from the Northwest Atlantic

    Science.gov (United States)

    Young, T.; Fuller, E.; Coleman, K.; Provost, M.; Pinsky, M. L.; St Martin, K.

    2016-02-01

    We know climate is changing and fish are moving in response to those changes. But we understand less about how harvesters are responding to these changes in fish distribution and the ramifications of those changes for fishing communities. Ecological and evolutionary theory suggests that organisms must move, adapt, or die in response to environmental changes, and a related frame may be relevant for human harvesters in the face of climate change. Furthermore, research suggests that there may be a portfolio effect: a wider diversity of catch may buffer harvesters from some effects of climate change. To get at these questions, we explored changes in fishing patterns among commercial fishing communities in the northeast US from 1997-2014 using NOAA-collected logbook data. We found that communities using more mobile gear (large trawl vessels) demonstrated a greater range of latitudinal shift than communities using any other gear. Latitudinal shift was also inversely related to species diversity of catch and port latitude in those communities: southern communities that caught few species shifted dramatically northward, and northern communities that caught many species did not demonstrate marked latitudinal shifts. Those communities that demonstrated larger latitudinal shifts also demonstrated smaller changes in catch composition than their more stationary counterparts. We also found that vessels are indeed leaving many, but not all, fisheries in this region. These results suggest that harvesters are moving, adapting, and leaving fisheries, and that there does appear to be a portfolio effect, with catch diversity mediating some of these responses. While these changes in fishing patterns cannot all be directly attributed to climate change per se, marine fishes in this region are shifting north rapidly, as is expected under climate change. This study provides a valuable test case for exploring the potential ramifications of climate change on coastal socio-ecological systems.

  7. Heart Rate and Oxygen Saturation Change Patterns During 6-min Walk Test in Subjects With Chronic Thromboembolic Pulmonary Hypertension.

    Science.gov (United States)

    Inagaki, Takeshi; Terada, Jiro; Yahaba, Misuzu; Kawata, Naoko; Jujo, Takayuki; Nagashima, Kengo; Sakao, Seiichiro; Tanabe, Nobuhiro; Tatsumi, Koichiro

    2017-12-26

    The 6-min walk test (6MWT) is commonly performed to assess functional status in patients with chronic thromboembolic pulmonary hypertension. However, changes in heart rate and oxygen saturation ( S pO 2 ) patterns during 6MWT in patients with chronic thromboembolic pulmonary hypertension remain unclear. Thirty-one subjects with chronic thromboembolic pulmonary hypertension were retrospectively evaluated to examine the relationships between the change in heart rate (Δheart rate), heart rate acceleration time, slope of heart rate acceleration, heart rate recovery during the first minute after 6MWT (HRR1), change in S pO 2 (Δ S pO 2 ), S pO 2 reduction time, and S pO 2 recovery time during 6MWT, and the severity of pulmonary hemodynamics assessed by right heart catheterization and echocardiography. Subjects with severe chronic thromboembolic pulmonary hypertension had significantly longer heart rate acceleration time (144.9 ± 63.9 s vs 96.0 ± 42.5 s, P = .033), lower Δheart rate (47.4 ± 16.9 vs 61.8 ± 13.6 beats, P = .02), and lower HRR1 (13.3 ± 9.0 beats vs 27.1 ± 9.2 beats, P pulmonary hypertension. Subjects with severe chronic thromboembolic pulmonary hypertension also had significantly longer S pO 2 reduction time (178.3 ± 70.3 s vs 134.3 ± 58.4 s, P = .03) and S pO 2 recovery time (107.6 ± 35.3 s vs 69.8 ± 32.7 s, P = .004) than did subjects with mild chronic thromboembolic pulmonary hypertension. Multivariate linear regression analysis showed only mean pulmonary arterial pressure independently was associated with heart rate acceleration time and slope of heart rate acceleration. Heart rate and S pO 2 change patterns during 6MWT is predominantly associated with pulmonary hemodynamics in subjects with chronic thromboembolic pulmonary hypertension. Evaluating heart rate and S pO 2 change patterns during 6MWT may serve a safe and convenient way to follow the change in pulmonary hemodynamics. Copyright © 2017 by Daedalus Enterprises.

  8. Diagnosis system for nozzles in high voltage equipment; Sistema de diagnostico para boquillas en equipos de alta tension

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez Nino, Jose; Escorsa Morales, Oscar [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico); Lopez Azamar, Ernesto [Comision Federal de Electricidad (Mexico)

    2000-07-01

    The nozzles used in high voltage electrical equipment, such as power transformers and circuit breakers, constitute the elements that present greater fault risk. On the other hand, the faults in the nozzles cause, in most of the cases catastrophic damages, that expose to risk the maintenance personnel of the plant and the peripheral equipment. With the purpose of contributing with on-line monitoring techniques that indicate the nozzles condition and allow to anticipate their possible fault, the Instituto de Investigaciones Electricas (IIE) performed for the laboratory of tests of equipment and materials (LAPEM) of Comision Federal de Electricidad (CFE), a project for the development of a system for the measurement of capacitive currents in these equipments. This system allows to determine the variation in capacitance and dielectric losses, and to determine the presence of internal partial discharges in nozzles of 115, 230 and 400 kV. With this information it is possible to determine the condition of the internal isolation of the nozzles and retire them from service before deterioration takes place that puts in danger the integrity of the equipment. The management of electrical equipment of the Instituto de Investigaciones Electricas developed for LAPEM a system that measures capacitive currents of power transformer nozzles. This system was designed with the purpose of installing it in a transformer of a 400 kV machine, in the fossil power station of Tula, Hidalgo, of the Comision Federal de Electricidad. [Spanish] Las boquillas empleadas en los equipos electricos de alta tension, como transformadores de potencia e interruptores, constituyen los elementos que presentan mayor riesgo de falla. Por otro lado, las fallas en las boquillas provocan en la mayoria de los casos danos catastroficos que ponen en riesgo al personal de mantenimiento de la planta y al equipo periferico. Con la finalidad de aportar tecnicas de monitoreo en linea que indiquen el estado de las

  9. Aerothermo-Structural Analysis of Low Cost Composite Nozzle/Inlet Components

    Science.gov (United States)

    Shivakumar, Kuwigai; Challa, Preeli; Sree, Dave; Reddy, D.

    1999-01-01

    This research is a cooperative effort among the Turbomachinery and Propulsion Division of NASA Glenn, CCMR of NC A&T State University, and the Tuskegee University. The NC A&T is the lead center and Tuskegee University is the participating institution. Objectives of the research were to develop an integrated aerodynamic, thermal and structural analysis code for design of aircraft engine components, such as, nozzles and inlets made of textile composites; conduct design studies on typical inlets for hypersonic transportation vehicles and setup standards test examples and finally manufacture a scaled down composite inlet. These objectives are accomplished through the following seven tasks: (1) identify the relevant public domain codes for all three types of analysis; (2) evaluate the codes for the accuracy of results and computational efficiency; (3) develop aero-thermal and thermal structural mapping algorithms; (4) integrate all the codes into one single code; (5) write a graphical user interface to improve the user friendliness of the code; (6) conduct test studies for rocket based combined-cycle engine inlet; and finally (7) fabricate a demonstration inlet model using textile preform composites. Tasks one, two and six are being pursued. Selected and evaluated NPARC for flow field analysis, CSTEM for in-depth thermal analysis of inlets and nozzles and FRAC3D for stress analysis. These codes have been independently verified for accuracy and performance. In addition, graphical user interface based on micromechanics analysis for laminated as well as textile composites was developed. Demonstration of this code will be made at the conference. A rocket based combined cycle engine was selected for test studies. Flow field analysis of various inlet geometries were studied. Integration of codes is being continued. The codes developed are being applied to a candidate example of trailblazer engine proposed for space transportation. A successful development of the code will

  10. Use of the FDA nozzle model to illustrate validation techniques in computational fluid dynamics (CFD) simulations.

    Science.gov (United States)

    Hariharan, Prasanna; D'Souza, Gavin A; Horner, Marc; Morrison, Tina M; Malinauskas, Richard A; Myers, Matthew R

    2017-01-01

    A "credible" computational fluid dynamics (CFD) model has the potential to provide a meaningful evaluation of safety in medical devices. One major challenge in establishing "model credibility" is to determine the required degree of similarity between the model and experimental results for the model to be considered sufficiently validated. This study proposes a "threshold-based" validation approach that provides a well-defined acceptance criteria, which is a function of how close the simulation and experimental results are to the safety threshold, for establishing the model validity. The validation criteria developed following the threshold approach is not only a function of Comparison Error, E (which is the difference between experiments and simulations) but also takes in to account the risk to patient safety because of E. The method is applicable for scenarios in which a safety threshold can be clearly defined (e.g., the viscous shear-stress threshold for hemolysis in blood contacting devices). The applicability of the new validation approach was tested on the FDA nozzle geometry. The context of use (COU) was to evaluate if the instantaneous viscous shear stress in the nozzle geometry at Reynolds numbers (Re) of 3500 and 6500 was below the commonly accepted threshold for hemolysis. The CFD results ("S") of velocity and viscous shear stress were compared with inter-laboratory experimental measurements ("D"). The uncertainties in the CFD and experimental results due to input parameter uncertainties were quantified following the ASME V&V 20 standard. The CFD models for both Re = 3500 and 6500 could not be sufficiently validated by performing a direct comparison between CFD and experimental results using the Student's t-test. However, following the threshold-based approach, a Student's t-test comparing |S-D| and |Threshold-S| showed that relative to the threshold, the CFD and experimental datasets for Re = 3500 were statistically similar and the model could be

  11. Design and Analysis of Metal-to-Composite Nozzle Extension Joints, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — As the operational demands of liquid rocket engines increases, so too does the need for improved design and manufacturing methods for metal-to-composite nozzle...

  12. Wedge Shock and Nozzle Exhaust Plume Interaction in a Supersonic Jet Flow

    Science.gov (United States)

    Castner, Raymond; Zaman, Khairul; Fagan, Amy; Heath, Christopher

    2014-01-01

    Fundamental research for sonic boom reduction is needed to quantify the interaction of shock waves generated from the aircraft wing or tail surfaces with the nozzle exhaust plume. Aft body shock waves that interact with the exhaust plume contribute to the near-field pressure signature of a vehicle. The plume and shock interaction was studied using computational fluid dynamics and compared with experimental data from a coaxial convergent-divergent nozzle flow in an open jet facility. A simple diamond-shaped wedge was used to generate the shock in the outer flow to study its impact on the inner jet flow. Results show that the compression from the wedge deflects the nozzle plume and shocks form on the opposite plume boundary. The sonic boom pressure signature of the nozzle exhaust plume was modified by the presence of the wedge. Both the experimental results and computational predictions show changes in plume deflection.

  13. The Effect of Variable Gravity on the Cooling Performance of a 16-Nozzle Spray Array

    National Research Council Canada - National Science Library

    Elston, Levi J; Yerkes, Kirk L; Thomas, Scott K; McQuillen, John

    2008-01-01

    The objective of this thesis was to investigate the cooling performance of a 16-nozzle spray array, using FC-72 as the working fluid, in variable gravity conditions with additional emphasis on fluid...

  14. Method and equipment of separation of gaseous and vaporous materials, particularly isotopes, with separation nozzles

    International Nuclear Information System (INIS)

    Becker, E.W.; Eisenbeiss, G.; Ehrfeld, W.

    1975-01-01

    The invention improves on the already known separation nozzle method by the two following steps: 1) The partial flows produced within the cascade with various shares of additional gas are introduced into the separating nozzle systems in such a manner that with regard to the additional gas, a molar fraction gradient is created which is in the opposite direction to the gradient created by the separation process. 2) The partial flows produced within the cascade with various compositions of the mixture of substances to be separated are introduced into the separating nozzle systems in such a manner that regarding the substances to be separated, a molar fraction gradient is created which is in the same direction as the molar fraction gradient formed by the separation process. Both measures can be separately applied or in combination with one another; flowsheets of the invented cascade circuits and separating nozzle systems are given. (GG/LH) [de

  15. Post-cast EDM method for reducing the thickness of a turbine nozzle wall

    Science.gov (United States)

    Jones, Raymond Joseph; Bojappa, Parvangada Ganapathy; Kirkpatrick, Francis Lawrence; Schotsch, Margaret Jones; Rajan, Rajiv; Wei, Bin

    2002-01-01

    A post-cast EDM process is used to remove material from the interior surface of a nozzle vane cavity of a turbine. A thin electrode is passed through the cavity between opposite ends of the nozzle vane and displaced along the interior nozzle wall to remove the material along a predetermined path, thus reducing the thickness of the wall between the cavity and the external surface of the nozzle. In another form, an EDM process employing a profile as an electrode is disposed in the cavity and advanced against the wall to remove material from the wall until the final wall thickness is achieved, with the interior wall surface being complementary to the profile surface.

  16. Facility Effects on a Helicon Plasma Source with a Magnetic Nozzle

    Data.gov (United States)

    National Aeronautics and Space Administration — Proposed here is an analysis of facility effects on a small helicon plasma source with a magnetic nozzle. Backpressure effects will first be recorded and analyzed....

  17. Research on precise control of 3D print nozzle temperature in PEEK material

    Science.gov (United States)

    Liu, Zhichao; Wang, Gong; Huo, Yu; Zhao, Wei

    2017-10-01

    3D printing technology has shown more and more applicability in medication, designing and other fields for its low cost and high timeliness. PEEK (poly-ether-ether-ketone), as a typical high-performance special engineering plastic, become one of the most excellent materials to be used in 3D printing technology because of its excellent mechanical property, good lubricity, chemical resistance, and other properties. But the nozzle of 3D printer for PEEK has also a series of very high requirements. In this paper, we mainly use the nozzle temperature control as the research object, combining with the advantages and disadvantages of PID control and fuzzy control. Finally realize a kind of fuzzy PID controller to solve the problem of the inertia of the temperature system and the seriousness of the temperature control hysteresis in the temperature control of the nozzle, and to meet the requirements of the accuracy of the nozzle temperature control and rapid reaction.

  18. Development of fabrication process of upper nozzle BIBLIS type of PWR fuel element

    International Nuclear Information System (INIS)

    Miranda, O.; Lorenzo, D.F.R.

    1982-01-01

    Process and parameters of milling and welding of a upper nozzle BIBLIS type prototype are presented. Milling process, cutting tools studies, production devices and inspection were developed and researched. (author) [pt

  19. Alternative Fabrication Designs for Carbon-Carbon (C-C) Nozzle Extensions, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — In order for carbon-carbon nozzle extensions and exit cones to serve as practical, low cost components for future Earth-to-Orbit propulsion systems, it is necessary...

  20. [Irregular breathing during the cardiopulmonary exercise test - from mildly irregular breathing pattern to periodic breathing of oscillatory ventilation type].

    Science.gov (United States)

    Várnay, František; Mífková, Leona; Homolka, Pavel; Dobšák, Petr

    The fluctuating course of tidal volume (VT), breathing frequency (DF) and minute ventilation (VE) during the cardio-pulmonary exercise test using a ramp incremental protocol occurs not only in patients, but relatively frequently also in healthy individuals. It can account for a number of irregularities in the course of the curves VO2, VCO2 and in particular of those of ventilatory equivalents for O2 and CO2 (EQO2, EQCO2) as well as curves of partial pressure of end-tidal oxygen and partial pressure of end-tidal carbon dioxide (PETO2, PETCO2), which are also used, inter alia, to establish ventilatory thresholds. The presence of exercise oscillatory ventilation (EOV) reflects the severity of heart failure and it is an independent predictor of the increased morbidity, cardiac and total mortality and sudden death caused by heart failure. However there is not a generally accepted universal definition of EOV available at present, as different criteria are used. We have not found a comparison which would indicate whether and how the "strength" of the prognostic criteria for EOV - established according to different methods - differs. Therefore it is very important to specify what method, or what criteria were used in the establishment of EOV.Key words: breathing pattern - EOV - exercise oscillatory ventilation - periodic breathing.