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Sample records for slot fish bypass

  1. Improved design of a high response slotted plate overboard bypass valve for supersonic inlets

    NASA Technical Reports Server (NTRS)

    Webb, J. A., Jr.; Mehmed, O.; Hiller, K. W.

    1973-01-01

    The electrohydraulically actuated slotted-plate bypass valve used to control the position of the normal shock during wind-tunnel investigations of supersonic inlets also has proven to be a valuable device for determining inlet dynamics and creating airflow disturbances. Operation of previous valves at high frequencies (to 100 Hz) for extended testing has resulted in numerous failures. An improved bypass-valve design is presented which increases the cyclic tolerance of the device considerably over past designs. The use of dynamic limit criteria to obtain an optimum actuator-piston size results in a frequency response which is flat within + or - 3 decibels to 120 Hz for a peak-to-peak variation of 20 percent of full area.

  2. Forward slanted slot throat stability bypass to increase the stable airflow range of a Mach 2.5 inlet with 60 percent internal contraction

    NASA Technical Reports Server (NTRS)

    Shaw, R. J.; Mitchell, G. A.; Sanders, B. W.

    1974-01-01

    The results of an experimental investigation to increase the stable airflow operating range of a supersonic mixed-compression inlet are presented. Two forward-slanted slot stability-bypass entrance configurations were tested. In terms of diffuser-exit corrected airflow, a large inlet stable airflow range of 18.5 percent was obtained with the superior configuration if a constant pressure was maintained in the bypass plenum. Limited unstart angle-of-attack data are presented.

  3. Passage of native riverine fishes through geometrically different sections of a vertical slot fishway on the Moselle River, Germany

    USGS Publications Warehouse

    Pitsch, Matthias; Mockenhaupt, Bernd; Castro-Santos, Theodore R.

    2014-01-01

    In order to study effects of different geometric types of pools or change of the flow direction on the passability of fish, sets of PIT antennas were installed inside a modern vertical slot fishway at the mouth of the River Moselle. Fish of 13 abundant species were caught and tagged with PIT tags in 2013 and released in the tailwater of Koblenz. 16% of the tagged fish were detected entering the fishway a short time after release. These individuals provided data on entry and passage rates for different sections of the fishway. Preliminary results show differences in passage time and passage rates between different sections of the fishway.

  4. Evaluation of Juvenile Fish Bypass and Adult Fish Facilities at Water Diversions in the Umatilla River; 1992 Annual Report.

    SciTech Connect

    Knapp, Suzanne M.

    1993-03-01

    We report on our progress from October 1991 through September 1992 in evaluating juvenile fish bypass facilities at Three Mile Falls and Westland dams on the Umatilla River. We also report on our progress from October 1991 through June 1992 in evaluating adult fish passage in the lower Umatilla River and adult fish passage facilities at Three Mile Falls Dam. The study is a cooperative effort by the Oregon Department of Fish and Wildlife (ODFW) and the Confederated Tribes of the Umatilla Indian Reservation (CTUIR). These are the study objectives addressed by ODFW and CTUIR: (1) Report A (ODFW): To evaluate the juvenile fish bypass facility in the West Extension Irrigation District Canal at Three Mile Falls Dam and document juvenile salmonid passage through the juvenile fish bypass facility and east-bank adult fish ladder. To measure velocity and develop trap designs at Westland Dam. (2) Report B (CTUIR): To examine the passage of adult salmonids at Three Mile Falls Dam. The study is part of a program to rehabilitate anadromous fish stocks in the Umatilla River Basin, including restoration of coho salmon (Oncorhynchus kisutch) and chinook salmon (Oncorhynchus tshawytscha), as well as enhancement of summer steelhead (Oncorhynchus mykiss).

  5. Evaluation of Juvenile Fish Bypass and Adult Fish Passage Facilities at Water Diversions in the Umatilla River; 1993 Annual Report.

    SciTech Connect

    Knapp, Suzanne M.

    1994-03-01

    This report presents progress from October 1992 through September 1993 in evaluating juvenile fish bypass facilities at Three Mile Falls, Maxwell, Westland, and Feed Canal dams on the Umatilla River, and in evaluating adult fish passage in the lower Umatilla River. Also reported is an effort to evaluate delayed mortality and stress responses of juvenile salmonids resulting from trapping and transport at high temperatures. These studies are part of a program to rehabilitate anadromous fish stocks in the matilla River Basin, including restoration of coho salmon and chinook salmon, as well as enhancement of summer steelhead.

  6. Evaluation of Juvenile Fish Bypass and Adult Fish Passage Facilities at Water Diversions on the Umatilla River; 1994 Annual Report.

    SciTech Connect

    Knapp, Suzanne M.

    1995-01-01

    We report on our progress from October 1993 through September 1994 in evaluating juvenile salmonid bypass facilities and juvenile salmonid passage through ladder facilities, and investigating passage conditions for juvenile fish at diversion dam facilities on the lower Umatilla River in northeastern Oregon. We also report on our progress in evaluating adult salmonid passage at and between dams on the lower Umatilla River and upriver migration using radio telemetry. Two principal studies are also included. Report A (ODFW): To evaluate the juvenile salmonid bypass facilities a Feed and Furnish canals, juvenile salmonid passage through fish ladders at Stanfield, Feed Canal, Westland, and Three Mile Falls dams, and the juvenile salmonid trap and haul procedures at Westland Canal. To investigate passage conditions at all passage facilities. Report B (CTUIR): To examine the passage of adult salmonids past diversions in the lower Umatilla River and their movement in the upper river after transport, using radio telemetry, and to assess factors for successful homing. These studies are part of a program to rehabilitate anadromous fish stocks in the Umatilla River Basin, including restoration of coho salmon (Oncorhynchus kisutch) and chinook salmon (Oncorhynchus tshawytscha), as well as enhancement of summer steelhead (Oncorhynchus mykiss).

  7. Evaluation of Juvenile Fish Bypass and Adult Fish Passage Facilities at Three-Mile Falls Dam; Umatilla River, Oregon, 1989 Annual Report.

    SciTech Connect

    Nigro, Anthony A.

    1990-09-01

    We report on our progress from October 1989 through September 1990 on evaluating juvenile fish bypass and adult fish passage facilities at Three Mile Falls Dam on the Umatilla River. The study is a cooperative effort by the Oregon Department of Fish and Wildlife (ODFW) and the Confederated Tribes of the Umatilla Indian Reservation (CTUIR). Study objectives addressed by ODFW and CTUIR are: (1) ODFW (Report A): Operate and evaluate the juvenile fish bypass system in the West Extension Irrigation District canal at Three Mile Falls Dam; and (2) CTUIR (Report 8): Examine the passage of adult salmonids at Three Mile Falls Dam. The study is part of a program to rehabilitate anadromous fish stocks in the Umatilla River Basin that includes restorations of coho salmon Oncorhynchus Wsutch and chinook salmon 0. tshawytscha and enhancement of summer steelhead 0. mytiss.

  8. Evaluation of Juvenile Fish Bypass and Adult Fish Passage Facilities at Water Diversions in the Umatilla River; 1990-1991 Progress Reports

    SciTech Connect

    Knapp, Suzanne M.

    1992-06-01

    We report on our effort from October 1990 through March 1991 to prepare for the evaluation of the juvenile fish bypass facility in the West Extension Irrigation District Canal at Three Mile Falls Dam on the Umatilla River. We also report on our preliminary activities to prepare for future evaluations at Maxwell and Westland diversion dams. A detailed sampling plan was written to guide our efforts in the evaluation process and associated preparatory activities were conducted. In the sampling plan, we developed experimental designs for evaluating the passage of juvenile salmonids through the bypass system including the evaluation at design flow of injury and mortality rates, and passage of juvenile salmonids through and over the screens. We designed and fabricated fish nets for screen leakage tests, and holding facilities for test fish. Modifications to improve evaluation activities were incorporated into the collection facility, and our sampling gear. We designed and fabricated collection systems for the juvenile fish bypass facilities at Maxwell and Westland diversion dams. Preliminary monitoring of system operation was performed at Westland Diversion Dam. We offer recommendations for improving preparations and designs of future evaluations, and also recommend that a detailed evaluation of the Maxwell and Westland juvenile facilities, including evaluation of fish condition and fish passage through or over the screens, be conducted.

  9. Movement of Fall Chinook Salmon Fry Oncorhynchus Tshawytscha : A Comparison of Approach Angles for Fish Bypass in a Modular Rotary Drum Fish Screen.

    SciTech Connect

    Neitzel, D.A.; Blanton, S.L.; Abernethy, C. Scott; Daly, D.S.

    1996-08-01

    The Pacific Northwest National Laboratory (PNNL) performed tests to determine whether a significant difference in fish passage existed between a 6-ft screening facility built perpendicularly to canal flow and an identical screening facility with the screen mounted at a 45-degree angle to the approach channel. A modular drum screen built by the Washington Department of Fish and Wildlife was installed at PNNL`s Aquatic Ecology research laboratory in Richland, Washington. Fall chinook salmon fry were introduced into the test system, and their movements were monitored. A total of 14 tests (400 fish per test) that lasted 20 hours were completed during April and May, 1996. There was no significant difference in fish passage rate through the two approach configurations. Attraction flow to the bypass across the face of the screen was more evident for the angled approach, although this did not appear to play a significant role in attracting fish to the bypass. Approach velocities at the face of the screen did not exceed the 0.4 fps criteria for either approach configuration and posed not threat to fish. No fish passed over, around, or through the drum screen during any test.

  10. Evaluation of Juvenile Salmonid Bypass Facilities and Passage at Water Diversions on the Lower Umatilla River; 1991-1995 Final Report.

    SciTech Connect

    Cameron, William A.; Knapp, Suzanne M.; Carmichael, Richard W.

    1997-07-01

    Outdated juvenile and adult fish passage facilities were recently reconstructed at the five major irrigation dams on the lower Umatilla River, Oregon to meet National marine Fisheries Service (NMFS) design standards. Changes in design at juvenile fish bypass facilities included reduced mesh size on the rotating drum screens, larger screening area, a more oblique orientation of the drum screens to canal flow, improved screen seals, replacement of bypass portals with vertical slot bypass channels, and increased bypass pipe diameters. Weir-and-pool adult fish ladders and jump pools were replaced with vertical-slot ladders. From 1991--1995, they investigated injury and travel rate of juvenile fish moving through the facilities, and efficiency of screens in preventing fish entry into the canals. Water velocities in front of canal screens, at bypass channel entrances, and at ladder diffusers were measured to assess adherence to NMFS criteria and identify hydraulic patterns. Biological evaluations were conducted by releasing and recapturing marked yearling summer steelhead (Oncorhynchus mykiss), yearling spring chinook salmon (O. tshawytscha), and subyearling fall chinook salmon (O. tshawytscha) in varying locations within the fish passage facilities.

  11. Evaluation of Wanapum Dam Bypass Configurations for Outmigrating Juvenile Salmon Using Virtual Fish: Numerical Fish Surrogate (NFS) Analysis

    DTIC Science & Technology

    2005-06-01

    modelling,” Ecological Modelling 157, 23-41. Goodwin, R., Nestler, J., Loucks , D., and Chapman, J. (2001). “Simulating mobile populations in aquatic...studying spatial behaviour of freshwater fishes in the natural environment,” Fish and Fisheries 1, 283-316. Nestler, J. M., Goodwin, R. A., and Loucks

  12. Sensitivity of the downward to sweeping velocity ratio to the bypass flow percentage along a guide wall for downstream fish passage

    USGS Publications Warehouse

    Mulligan, Kevin; Towler, Brett; Haro, Alexander J.; Ahlfeld, David P.

    2017-01-01

    Partial-depth impermeable guidance structures (or guide walls) are used as a method to assist in the downstream passage of fish at a hydroelectric facility. However, guide walls can result in a strong downward velocity causing the approaching fish to pass below the wall and into the direction of the turbine intakes. The objective of this study was to describe how the ratio of the vertical velocity to the sweeping velocity magnitude changes along the full length and depth of a guide wall under a wide range of bypass flow percentages within a power canal. This paper focused on two guide wall configurations, each set at an angle of 45 ° to the approaching flow field and at a depth of 10 and 20 ft (3.05 and 6.10 m). The hydraulic conditions upstream of each guide wall configuration were shown to be impacted by a change in the bypass flow percentage, not only near the bypass but also at upstream sections of the guide wall. Furthermore, the effect of changing the bypass flow percentage was similar for both guide wall depths. In both cases, the effect of increasing the bypass flow percentage was magnified closer to the bypass and deeper in the water column along the guide wall.

  13. Effects of an agricultural drainwater bypass on fishes inhabiting the Grassland Water District and the lower San Joaquin River, California

    USGS Publications Warehouse

    Saiki, M.K.; Martin, B.A.; Schwarzbach, S.E.; May, T.W.

    2001-01-01

    The Grassland Bypass Project, which began operation in September 1996, was conceived as a means of diverting brackish selenium-contaminated agricultural drainwater away from canals and sloughs needed for transporting irrigation water to wetlands within the Grassland Water District (the Grasslands), Merced County, California. The seleniferous drainwater is now routed into the San Luis Drain for conveyance to North Mud Slough and eventual disposal in the San Joaquin River. The purpose of this study was to determine the extent to which the Grassland Bypass Project has affected fishes in sloughs and other surface waters within and downstream from the Grasslands. During September-October 1997, 9,795 fish representing 25 species were captured at 13 sampling sites. Although several species exhibited restricted spatial distributions, association analysis and cluster analysis failed to identify more than one fish species assemblage inhabiting the various sites. However, seleniferous drainwater from the San Luis Drain has influenced selenium concentrations in whole fish within North Mud Slough and the San Joaquin River. The highest concentrations of selenium (12-23 ??g/g, dry weight basis) were measured in green sunfish Lepomis cyanellus from the San Luis Drain where seleniferous drainwater is most concentrated, whereas the second highest concentrations occurred in green sunfish (7.6-17 ??g/g) and bluegills Lepomis macrochirus (14-18 ??g/g) from North Mud Slough immediately downstream from the drain. Although there was some variation, fish in the San Joaquin River generally contained higher body burdens of selenium when captured immediately below the mouth of North Mud Slough (3.1-4.8 ??g/g for green sunfish, 3.7-5.0 ??g/g for bluegills) than when captured upstream from the mouth (0.67-3.3 ??g/g for green sunfish, 0.59-3.7 ??g/g for bluegills). Waterborne selenium was the single most important predictor of selenium concentrations in green sunfish and bluegills, as judged by

  14. Movement and Injury Rates for Three Life Stages of Spring Chinook Salmon Oncorhynchus Tshawytscha : A Comparison of Submerged Orifices and an Overflow Weir for Fish Bypass in a Modular Rotary Drum Fish Screen : Annual Report 1995.

    SciTech Connect

    Abernethy, C. Scott; Neitzel, Duane A.; Mavros, William V.

    1996-03-01

    The Pacific Northwest National Laboratory (PNNL) evaluated the effectiveness of 6-in. and 2-in. submerged orifices, and an overflow weir for fish bypass at a rotary drum fish screening facility. A modular drum screen built by the Washington Department of Fish and Wildlife (WDFW) was installed at PNNL`s Aquatic Ecology research laboratory in Richland, Washington. Fry, subyearlings, and smolts of spring chinook salmon (Oncorhynchus tshawyacha) were introduced into the test system, and their movement and injury rates were monitored. A total of 33 tests (100 fish per test) that lasted from 24 to 48 hr were completed from 1994 through 1995. Passage rate depended on both fish size and bypass configuration. For fry/fingerling spring chinook salmon, there was no difference in passage rate through the three bypass configurations (2-in. orifice, 6-in. orifice, or overflow weir). Subyearlings moved sooner when the 6-in. orifice was used, with more than 50% exiting through the fish bypass in the first 8 hr. Smolts exited quickly and preferred the 6-in. orifice, with over 90% of the smolts exiting through the bypass in less than 2 hr. Passage was slightly slower when a weir was used, with 90% of the smolts exiting in about 4 hr. When the 2-in. orifice was used in the bypass, 90% of the smolts did not exit until after 8 hr. In addition, about 7% of the smolts failed to migrate from the forebay within 24 hr, indicating that smolts were significantly delayed when the 2-in. orifice was used. Few significant injuries were detected for any of the life stages. However, light descaling occurred on about 15% of chinook salmon smolts passing through the 2-in. orifice. Although a single passage through the orifice did not appear to cause significant scale loss or other damage, passing through several screening facilities with 2-in. orifices could cause cumulative injuries.

  15. Survival of juvenile chinook salmon and coho salmon in the Roza Dam fish bypass and in downstream reaches of the Yakima River, Washington, 2016

    USGS Publications Warehouse

    Kock, Tobias J.; Perry, Russell W.; Hansen, Amy C.

    2016-12-22

    Estimates of juvenile salmon survival are important data for fishery managers in the Yakima River Basin. Radiotelemetry studies during 2012–14 showed that tagged juvenile Chinook salmon (Oncorhynchus tshawytscha) that passed through the fish bypass at Roza Dam had lower survival than fish that passed through other routes at the dam. That study also identified flow-survival relationships in the reaches between the Roza Dam tailrace and Sunnyside Dam. During 2012–14, survival also was estimated through reaches downstream of Sunnyside Dam, but generally, sample sizes were low and the estimates were imprecise. In 2016, we conducted an evaluation using acoustic cameras and acoustic telemetry to build on information collected during the previous study. The goal of the 2016 research was to identify areas where mortality occurs in the fish bypass at Roza Dam, and to estimate reach-specific survival in reaches downstream of the dam. The 2016 study included juvenile Chinook salmon and coho salmon (O. kisutch).Three acoustic cameras were used to observe fish behavior (1) near the entrances to the fish bypass, (2) at a midway point in the fish bypass (convergence vault), and (3) at the bypass outfall. In total, 504 hours of acoustic camera footage was collected at these locations. We determined that smolt-sized fish (95–170 millimeters [mm]) were present in the highest proportions at each location, but predator-sized fish (greater than 250 mm) also were present at each site. Fish presence generally peaked during nighttime hours and crepuscular periods, and was low during daytime hours. In the convergence vault, smolt-sized fish exhibited holding behavior patterns, which may explain why some fish delayed while passing through the bypass.Some of the acoustic-tagged fish were delayed in the fish bypass following release, but there was no evidence to suggest that they experienced higher mortality than fish that were released at the bypass outfall or downstream of the dam

  16. Both dietary fish-oil supplementation and aspirin fail to inhibit atherosclerosis in long-term vein bypass grafts in moderately hypercholesterolemic nonhuman primates.

    PubMed

    Boerboom, L E; Olinger, G N; Almassi, G H; Skrinska, V A

    1997-08-05

    Aortocoronary vein bypass grafts are vulnerable to late atherosclerotic occlusion. Conventional platelet inhibitor therapy provides early but not persistent protection against graft failure. Evidence suggests that consumption of marine foods may reduce cardiovascular disease, possibly because of the unique long-chain unsaturated omega-3 fatty acids present in these foods. We hypothesized that dietary fish-oil supplementation would protect against atherosclerosis in vein bypass grafts. Thirty-three moderately hypercholesterolemic cynomolgus macaques were divided into four groups: control, control+aspirin, fish oil, and fish oil+aspirin. Each control group received olive oil as placebo to equalize calorie and fat consumption with that of the fish-oil groups. Both oils were in ethyl ester form, with the fish oil providing 0.88 g/d eicosapentaenoic acid. The aspirin dose was 40 mg/d. Cephalic vein grafts were interposed bilaterally in the carotid arteries and excised for analysis at 4 years. Bleeding time was significantly prolonged in all groups receiving fish oil or aspirin (P<.05). Plasma cholesterol levels were similar among groups, averaging 6.9+/-2.4 mmol/L (267+/-94 mg/dL). The extent of atherosclerosis in vein grafts did not differ among groups as evaluated both by Sudan IV staining of intimal lipid lesions (27+/-21% of total surface area, P=.89) and analysis of cholesterol content (236+/-203 nmol/mg, 9.1+/-7.8 microg/mg, P=.85). Vein graft connective tissue composition was also unaffected by treatment. Our findings do not support the use of concentrated dietary fish-oil supplements or aspirin for the prevention of atherosclerosis in long-term vein bypass grafts. Consumption of fish flesh or less refined oil preparations could have effects different from those of the purified fish-oil ethyl esters we used.

  17. Interrupted monogroove slot

    NASA Technical Reports Server (NTRS)

    Brown, Richard F. (Inventor); Edelstein, Fred (Inventor); Kosson, Robert L. (Inventor)

    1993-01-01

    An interrupted monogroove slot in a heat pipe facilitates priming of the heat pipe under zero gravity conditions by preventing the monogroove slot from completely priming before the liquid channel is primed.

  18. Highly dispersive slot waveguides.

    PubMed

    Zhang, Lin; Yue, Yang; Xiao-Li, Yinying; Beausoleil, Raymond G; Willner, Alan E

    2009-04-27

    We propose a slot-waveguide with high dispersion, in which a slot waveguide is coupled to a strip waveguide. A negative dispersion of up to -181520 ps/nm/km is obtained due to a strong interaction of the slot and strip modes. A flat and large dispersion is achievable by cascading the dispersive slot-waveguides with varied waveguide thickness or width for dispersion compensation and signal processing applications. We show - 31300 ps/nm/km dispersion over 147-nm bandwidth with <1% variance.

  19. Investigating passage of ESA-listed juvenile fall Chinook salmon at Lower Granite Dam during winter when the fish bypass system is not operated

    USGS Publications Warehouse

    Kock, Tobias J.; Tiffan, Kenneth F.; Connor, William P.

    2007-01-01

    During the winter of 2006-07, we radio and passive integrated transponder (PIT) tagged, and released 99 juvenile fall Chinook salmon to evaluate over-wintering behavior and dam passage in the lower Snake River, Washington. All fish were released 10 km upstream of Lower Granite Dam at Granite Point in early November, 2006. Fixed radio telemetry detection sites located in the forebay and tailrace areas of Lower Granite, Little Goose, Lower Monumental, Ice Harbor, Bonneville dams, and at Lyle, Washington were used to monitor fish movements and dam passage through early-May 2007. Of the 99 fish released during our study, 80 passed Lower Granite Dam and were detected at downstream detection sites, 37 passed Little Goose Dam, 41 passed Lower Monumental Dam, 31 passed Ice Harbor Dam, 18 passed Lyle, WA, and 13 passed Bonneville Dam. Of the fish that passed Lower Granite Dam in the fall, 63 fish did so during the extended bypass period from November 1 through December 16. Of these fish, 53 were also detected by the PIT-tag interrogation system. Fifteen of the fish that passed Lower Granite Dam in the fall continued to pass lower Snake River dams and exit the system by the end of January. The remaining fish either died, their tags failed, or they resided in Little Goose Reservoir until spring when relatively few continued their seaward migration. Passage of tagged fish past lower Snake River dams generally declined during the winter as temperatures decreased, but increased again in the spring as temperatures and flows increased. Fish residence times in reservoirs and forebays was lengthy during the winter (up to 160 d), and varied by reservoir and time of year. We observed no diel trends in fish passage. Very few fish were detected at PIT-tag interrogation sites in the spring compared to detection by radio telemetry detection sites indicating that fish may have passed via spill. We believe that passage of overwintering juvenile fall Chinook salmon during winter is due more

  20. Investigating passage of ESA-listed juvenile fall Chinook salmon at Lower Granite Dam during winter when the fish bypass system is not operated. 2006 Annual Report

    USGS Publications Warehouse

    Tiffan, Kenneth F.; Kock, Tobias J.; Connor, William P.

    2007-01-01

    During the winter of 2005-06, we radio and PIT tagged and released 48 juvenile fall Chinook salmon to evaluate over-wintering behavior and dam passage in the lower Snake River, Washington. Fish were released at the upstream end of the Lower Granite Dam forebay in November and December 2005. Fixed radio telemetry detection sites located in forebay and tailrace areas of Lower Granite, Little Goose, Lower Monumental and Ice Harbor dams were used to monitor fish movements and dam passage through early-May 2006. Of the 48 fish released during our study, 39 (81 %) passed Lower Granite Dam and were detected at downstream detection sites, 29 (60%) passed Little Goose Dam, 25 (52%) passed Lower Monumental Dam, and 15 (31%) passed Ice Harbor Dam. Thirty-seven (95%), 23 (79%), 16 (64%), and 9 (60%) of the fish that passed Lower Granite, Little Goose, Lower Monumental, and Ice Harbor dams respectively, did so when the fish bypass system was not operated. Passage of tagged fish past lower Snake River dams generally declined during the winter, but increased again after bypass began in April. Fish residence times in reservoirs and forebays was lengthy during the winter (up to 118 d), and varied by reservoir and time of year. We observed no diel passage trends. Only 15 of the 48 fish were subsequently detected at a PIT-tag interrogation site the following spring. We believe that passage of overwintering juvenile fall Chinook salmon during winter is due more to chance than directed downstream movement. Since the primary route of passage during the winter is through powerhouse turbines, the potential exists for increased mortality for over-wintering juvenile fall Chinook salmon in the Snake River. Our findings also have implications for transportation studies of subyearling fall Chinook salmon in the Snake River. Specifically, the finding that some fish can pass undetected during the winter may bias smolt-to-adult return rate calculations that are typically used to measure the

  1. TAPERED DEFINING SLOT

    DOEpatents

    Pressey, F.W.

    1959-09-01

    An improvement is reported in the shape and formation of the slot or opening in the collimating slot member which forms part of an ion source of the type wherein a vapor of the material to be ionized is bombarded by electrons in a magnetic field to strike an arc-producing ionization. The defining slot is formed so as to have a substantial taper away from the cathode, causing the electron bombardment from the cathode to be dispersed over a greater area reducing its temperature and at the same time bringing the principal concentration of heat from the electron bombardment nearer the anode side of the slot, thus reducing deterioration and prolonging the life of the slot member during operation.

  2. Modulated Elliptical Slot

    NASA Technical Reports Server (NTRS)

    Abou-Khousa, M. A.

    2009-01-01

    A novel modulated slot design has been proposed and tested. The proposed slot is aimed to replace the inefficient small dipoles used in conventional MST-based imaging systems. The developed slot is very attractive as MST array element due to its small size and high efficiency/modulation depth. In fact, the developed slot has been successfully used to implement the first prototype of a microwave camera operating at 24 GHZ. It is also being used in the design of the second generation of the camera. Finally, the designed elliptical slot can be used as an electronically controlled waveguide iris for many other purposes (for instance in constructing waveguide reflective phase shifters and multiplexers/switches).

  3. Outmigration of landlocked Atlantic salmon (Salmo salar) smolts and effectiveness of an angled trash rack/fish bypass structure at a small scale hydroelectric facility. [Salmo salar

    SciTech Connect

    Nettles, D.C.; Gloss, S.P.

    1985-01-01

    Modes of downstream passage (penstock, spillway, diversion chute) by Atlantic salmon (Salmo salar) smolts were monitored using radio telemetry to assess the effectiveness of an angled trash rack/fish bypass structure at a small hydroelectric dam on the Boquet River, New York. Telemetry of 170 Atlantic salmon smolts and visual observations of stocked smolts were used to determine aspects of Atlantic salmon outmigration behavior. Smolts initiated mass migrations after river temperatures reached or exceeded 10/sup 0/C. Many radio-tagged smolts interrupted movements upon reaching ponded waters and/or the dam. River flow did not (P > .05) affect the frequency of migratory movements, passages, or rate of movement. Migrations were of approximately 30 days duration. Passages at the dam occurred primarily at night (61%) with diurnal passages (17%) and crepuscular passages (17%) of secondary importance. Timing of 5% of the passages was undetermined. All passages which occurred when angled trash racks were in place were through the bypass or over the spillway. Six (6) passages occurred when trash racks perpendicular to the penstock were in place: 3 of these were penstock passages. The angled trash rack and bypass structure served to reduce entrainment.

  4. Rotary slot dog

    DOEpatents

    Cutburth, Ronald W.; Smauley, David A.

    1987-01-01

    A clamp or dog is disclosed which preferably comprises a slotted stepped cylindrical body which is inserted into a hole in a workpiece and then fastened to a base or fixture using a screw which is inserted through the slot. The stepped configuration provides an annular clamping surface which securely clamps the workpiece against the base or fixture. The slotted cylindrical configuration permits adjustment of the workpiece and retaining clamp in any direction, i.e., over 360.degree., relative to the mounting position of the screw in the base or fixture.

  5. Slotted Aircraft Wing

    NASA Technical Reports Server (NTRS)

    Vassberg, John C. (Inventor); Gea, Lie-Mine (Inventor); McLean, James D. (Inventor); Witowski, David P. (Inventor); Krist, Steven E. (Inventor); Campbell, Richard L. (Inventor)

    2006-01-01

    An aircraft wing includes a leading airfoil element and a trailing airfoil element. At least one slot is defined by the wing during at least one transonic condition of the wing. The slot may either extend spanwise along only a portion of the wingspan, or it may extend spanwise along the entire wingspan. In either case, the slot allows a portion of the air flowing along the lower surface of the leading airfoil element to split and flow over the upper surface of the trailing airfoil element so as to achieve a performance improvement in the transonic condition.

  6. Turnstile slot antenna

    NASA Technical Reports Server (NTRS)

    Munson, R. E. (Inventor)

    1974-01-01

    A turnstile slot antenna is disclosed, the antenna being for and integral with a spacecraft having a substantially cylindrical body portion. The antenna comprises a circumferential slot about the periphery of the spacecraft body portion with an annular wave guide cavity defining a radial transmission line disposed within the spacecraft body portion behind and in communication with the circumferential slot. Feed stubs and associated transmission apparatus are provided to excite the annular cavity in quadrature phase such that an omnidirectional, circularly polarized, rotating radiation pattern is generated. The antenna of the instant invention has utility both as a transmitting and receiving device, and ensures continuous telemetry and command coverage with the spacecraft.

  7. CIRCULAR CAVITY SLOT ANTENNA

    DOEpatents

    Kerley, P.L.

    1959-01-01

    A small-size antenna having a doughnut-shaped field pattern and which can act both as an antenna and a resonant circuit is described. The antenna is of the slotted type and comprises a resonant cavity with a center hole. A circular slot is provided in one wall of the cavity concentric with the hole and a radio frequency source is connected across the slot. The pattern and loading of the antenna are adjusted by varying the position and shape of a center element slidably disposed within the hole and projecting from the slotted side of the resonant cavity. The disclosed structure may also be used to propagate the oscillator signal down a transniission line by replacing the center element with one leg of the transmission line in a spaced relation from the walls of the cavity.

  8. Slotted Aircraft Wing

    NASA Technical Reports Server (NTRS)

    McLean, James D. (Inventor); Witkowski, David P. (Inventor); Campbell, Richard L. (Inventor)

    2006-01-01

    A swept aircraft wing includes a leading airfoil element and a trailing airfoil element. At least one full-span slot is defined by the wing during at least one transonic condition of the wing. The full-span slot allows a portion of the air flowing along the lower surface of the leading airfoil element to split and flow over the upper surface of the trailing airfoil element so as to achieve a performance improvement in the transonic condition.

  9. Auctioning Airport Slots?

    NASA Technical Reports Server (NTRS)

    Gruyer, Nicolas; Lenoir, Nathalie

    2003-01-01

    The current allocation of slots on congested European airports constitutes an obstacle to the effective liberalisation of air transportation undertaken in Europe. With a view to favouring effluent slot utilisation and competition, as is the goal of the Euopean commission, we propose to use a market mechanism, based on temporary" utilisation licences. In order to allocate those licences, we propose and describe an iterated combinatorial auction mechanism where a percentage of licences would be reallocated each season. A secondary market would also be set up in order to reallocate slots during a season. Since a combinatorial auction involve a complex optimisation procedure, we describe how it can be made to work in the case of auctions.

  10. Feather seal slot for vanes

    SciTech Connect

    Del Mastro, B. P.; Eckart, F.

    1985-10-22

    The slots for accommodating feather seals in the turbine vanes of a gas turbine engine has the end thereof sealed off by use of weld wire inserted into the slot and simultaneously welded and cut to the required length.

  11. Synthesis of Sensor Fish Data for Assessment of Fish Passage Conditions at Turbines, Spillways, and Bypass Facilities – Phase 1: The Dalles Dam Spillway Case Study

    SciTech Connect

    Deng, Zhiqun; Serkowski, John A.; Fu, Tao; Carlson, Thomas J.; Richmond, Marshall C.

    2007-12-31

    This report summarizes the characterization of spillway passage conditions at The Dalles Dam in 2006 and the effort to complete a comprehensive database for data sets from The Dalles Dam spillway Sensor Fish and balloon-tagged live fish experiments. Through The Dalles Dam spillway case study, Pacific Northwest National Laboratory (PNNL) researchers evaluated the database as an efficient means for accessing and retrieving system-wide data for the U.S Army Corps of Engineers (USACE).

  12. An unusual cause of chronic abdominal pain after laparoscopic Roux en Y gastric bypass: Case report of a penetrating fish bone causing adhesions at the biliary-digestive junction resulting in partial obstruction and chronic symptoms

    PubMed Central

    Ochieng, Vincent; Hendrickx, Leo; Valk, Jody

    2016-01-01

    Background The management of chronic abdominal pain after laparoscopic Roux-en-Y gastric bypass (LRYGP) is complex and challenging. Foreign body intestinal perforation including that caused by fish bones has previously been reported in the literature and if clinically unrecognized, can cause significant morbidity and mortality. Fish bone perforation as a cause of chronic abdominal pain after LRYGP has rarely been reported. Summary The unusual case of a 54 year old female presenting with recurrent episodes of postprandial pain 2 years after LRYGP is reported. Previous radiological and endoscopic investigations did not reveal any abnormality and after the most recent clinical presentation, a laparoscopic exploration was performed. A protruding fish bone at the biliary-digestive junction was discovered intra-operatively and successfully extracted. Dense adhesions between the involved intestinal loops were lysed in an attempt to improve intestinal transit and subsequently relieve post-prandial pain. Conclusion This case highlights the possibility of a missed fish bone perforation causing chronic postprandial abdominal pain and discomfort in a patient with a Roux-en-Y gastric bypass anatomy. Foreign body perforation is a rare cause of abdominal pain after gastric bypass that should be considered when evaluating chronic abdominal pain symptoms after LRYGP. PMID:27107305

  13. Heat Pipe With Interrupted Slot

    NASA Technical Reports Server (NTRS)

    Brown, Richard F.; Kosson, Robert L.; Edelstein, Fred

    1994-01-01

    Newer version of heat pipe slot interrupted by plug or, if heat pipe is cast, by bridge of heat-pipe material cast integrally across groove. Small barrier assists in priming heat pipe. Vapor and noncondensible gas still accumulates in liquid channel at evaporator before or during startup, but barrier keeps liquid out of small part of slot at bubble. Dry part of slot allows bubble to escape into vapor channel, making room for liquid to move in during startup.

  14. Endfire tapered slot antenna characteristics

    NASA Technical Reports Server (NTRS)

    Schaubert, D. H.

    1989-01-01

    Typical configurations and operating characteristics for endfire tapered slot antennas are described. The feed transition modeling and moment method modeling techniques are utilized to predict antenna performance. The radiation pattern and cross polarization properties for the linearly tapered slot antennas are examined. Endfire tapered slot antennas are applicable for wide-band scanning arrays and focal plane arrays for imaging and multiple beam reflector systems.

  15. Slotted photonic crystal biosensors

    NASA Astrophysics Data System (ADS)

    Scullion, Mark Gerard

    Optical biosensors are increasingly being considered for lab-on-a-chip applications due to their benefits such as small size, biocompatibility, passive behaviour and lack of the need for fluorescent labels. The light guiding mechanisms used by many of them result in poor overlap of the optical field with the target molecules, reducing the maximum sensitivity achievable. This thesis presents a new platform for optical biosensors, namely slotted photonic crystals, which engender higher sensitivities due to their ability to confine, spatially and temporally, the peak of optical mode within the analyte itself. Loss measurements showed values comparable to standard photonic crystals, confirming their ability to be used in real devices. A novel resonant coupler was designed, simulated, and experimentally tested, and was found to perform better than other solutions within the literature. Combining with cavities, microfluidics and biological functionalization allowed proof-of-principle demonstrations of protein binding to be carried out. High sensitivities were observed in smaller structures than most competing devices in the literature. Initial tests with cellular material for real applications was also performed, and shown to be of promise. In addition, groundwork to make an integrated device that includes the spectrometer function was also carried out showing that slotted photonic crystals themselves can be used for on-chip wavelength specific filtering and spectroscopy, whilst gas-free microvalves for automation were also developed. This body of work presents slotted photonic crystals as a realistic platform for complete on-chip biosensing; addressing key design, performance and application issues, whilst also opening up exciting new ideas for future study.

  16. Heart bypass surgery

    MedlinePlus

    Off-pump coronary artery bypass; OPCAB; Beating heart surgery; Bypass surgery - heart; CABG; Coronary artery bypass graft; Coronary artery bypass surgery; Coronary bypass surgery; Coronary artery disease - CABG; CAD - CABG; Angina - ...

  17. Slotted Photonic Crystal Sensors

    PubMed Central

    Scullion, Mark G.; Krauss, Thomas F.; Di Falco, Andrea

    2013-01-01

    Optical biosensors are increasingly being considered for lab-on-a-chip applications due to their benefits such as small size, biocompatibility, passive behaviour and lack of the need for fluorescent labels. The light guiding mechanisms used by many of them results in poor overlap of the optical field with the target molecules, reducing the maximum sensitivity achievable. This review article presents a new platform for optical biosensors, namely slotted photonic crystals, which provide higher sensitivities due to their ability to confine, spatially and temporally, the optical mode peak within the analyte itself. Loss measurements showed values comparable to standard photonic crystals, confirming their ability to be used in real devices. A novel resonant coupler was designed, simulated, and experimentally tested, and was found to perform better than other solutions within the literature. Combining with cavities, microfluidics and biological functionalization allowed proof-of-principle demonstrations of protein binding to be carried out. Higher sensitivities were observed in smaller structures than possible with most competing devices reported in the literature. This body of work presents slotted photonic crystals as a realistic platform for complete on-chip biosensing; addressing key design, performance and application issues, whilst also opening up exciting new ideas for future study. PMID:23503295

  18. Water flows from slotted pipes

    SciTech Connect

    Olson, D.A.

    1981-04-01

    Results of experiments and analyses that determine jet flow distribution from slotted pipes of dimensions typical for OC-OTEC evaporators or condensers are described. For a pipe with a 6.3-cm inside diameter and 0.64-cm wide slot, the measured and predicted jet flow was low and nearly parallel to the pipe at the entrance, and high and perpendicular to the pipe only near the closed end. Slot lengths ranged from 1.5 m to 4.6 m, and inlet flow rates varied from 6 kg/s to 17 kg/s. Friction reduces the pressure in the entrance and intermediate portions of the pipe, while the rapidly decelerating flow produces high pressure recovery as it approaches the closed end. In the region of high flow next to the closed end, the ratio of slot area (slot length times width) to pipe cross-sectional area is less than two. To use a slotted pipe for generating falling jets in an OC-OTEC plant, the slot length should be 1 m or less (for a pipe with a 6.3-cm inside diameter and a 0.64-cm wide slot).

  19. Planar slot coupled microwave hybrid

    DOEpatents

    Petter, Jeffrey K.

    1991-01-01

    A symmetrical 180.degree. microwave hybrid is constructed by opening a slot line in a ground plane below a conducting strip disposed on a dielectric substrate, creating a slot coupled conductor. Difference signals propagating on the slot coupled conductor are isolated on the slot line leaving sum signals to propagate on the microstrip. The difference signal is coupled from the slot line onto a second microstrip line for transmission to a desired location. The microstrip branches in a symmetrical fashion to provide the input/output ports of the 180.degree. hybrid. The symmetry of the device provides for balance and isolation between sum and difference signals, and provides an advantageous balance between the power handling capabilities and the bandwidth of the device.

  20. Meteorological radar facility (MRF) slot conductance investigations

    NASA Technical Reports Server (NTRS)

    Ratkevich, A. E.

    1977-01-01

    A preliminary meteorological radar facility (MRF) array design was completed in support of the slot conductance measurement program. Three different slot measurement techniques were evaluated. The selection of the probe comparison measurement technique was selected as the principal experimental method with the impedance measurement technique chosen to measure a few higher conductance slots to be used as reference slots. The impedance of 43 slots in 0.9 x 0.4 inch standard waveguide and of 40 slots in 0.835 x 0.4 inch waveguide was measured. Also, impedance measurements were made of a few slots using image planes to simulate mutual coupling effects. The measured and theoretical conductance, susceptance, and radiation phase data are presented in graphic form as a function of slot displacement for constant slot length, and of slot length for constant slot displacement. It is concluded that the proposed MRF array design approach is a feasible one.

  1. Electrospraying from nanofluidic capillary slot

    NASA Astrophysics Data System (ADS)

    Arscott, Steve; Troadec, David

    2005-09-01

    We present here an original electrospray emitter tip based on a nanofluidic capillary slot. The nanofabrication involves focused ion beam etching to form the slot which has a cross-section of 50×300nm and a length of 4μm. The liquid is deformed into the nanofluidic capillary slot by capillary action; the electrospray is produced by the application of a low voltage. Using a water-methanol-formic acid solution, we have observed an electrospray onset voltage of 125V. At a measured electrospray current of 1nA, the unforced flow-rate is estimated to be 110pLmin-1.

  2. 14 CFR 93.223 - Slot withdrawal.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Slot withdrawal. 93.223 Section 93.223... (excluding slots used for operations described in § 93.212(a)(1)), if withdrawal would reduce the number of... Operations at High Density Traffic Airports § 93.223 Slot withdrawal. (a) Slots do not represent a property...

  3. Cowlitz Falls Fish Passage.

    SciTech Connect

    1995-09-01

    The upper Cowlitz was once home to native salmon and steelhead. But the combined impacts of overharvest, farming, logging and road building hammered fish runs. And in the 1960s, a pair of hydroelectric dams blocked the migration path of ocean-returning and ocean-going fish. The lower Cowlitz still supports hatchery runs of chinook, coho and steelhead. But some 200 river miles in the upper river basin--much of it prime spawning and rearing habitat--have been virtually cut off from the ocean for over 26 years. Now the idea is to trap-and-haul salmon and steelhead both ways and bypass previously impassable obstacles in the path of anadromous fish. The plan can be summarized, for the sake of explanation, in three steps: (1) trap and haul adult fish--collect ocean-returning adult fish at the lowermost Cowlitz dam, and truck them upstream; (2) reseed--release the ripe adults above the uppermost dam, and let them spawn naturally, at the same time, supplement these runs with hatchery born fry that are reared and imprinted in ponds and net pens in the watershed; (3) trap and haul smolts--collection the new generation of young fish as they arrive at the uppermost Cowlitz dam, truck them past the three dams, and release them to continue their downstream migration to the sea. The critical part of any fish-collection system is the method of fish attraction. Scientists have to find the best combination of attraction system and screens that will guide young fish to the right spot, away from the turbine intakes. In the spring of 1994 a test was made of a prototype system of baffles and slots on the upriver face of the Cowlitz Falls Dam. The prototype worked at 90% efficiency in early tests, and it worked without the kind of expensive screening devices that have been installed on other dams. Now that the success of the attraction system has been verified, Harza engineers and consultants will design and build the appropriate collection part of the system.

  4. Yolo Bypass Juvenile Salmon Utilization Study 2016—Summary of acoustically tagged juvenile salmon and study fish release, Sacramento River, California

    USGS Publications Warehouse

    Liedtke, Theresa L.; Hurst, William R.

    2017-09-12

    The Yolo Bypass is a flood control bypass in Sacramento Valley, California. Flood plain habitats may be used for juvenile salmon rearing, however, the potential value of such habitats can be difficult to evaluate because of the intermittent nature of inundation events. The Yolo Bypass Juvenile Salmon Utilization Study (YBUS) used acoustic telemetry to evaluate the movements and survival of juvenile salmon adjacent to and within the Yolo Bypass during the winter of 2016. This report presents numbers, size data, and release data (times, dates, and locations) for the 1,197 acoustically tagged juvenile salmon released for the YBUS from February 21 to March 18, 2016. Detailed descriptions of the surgical implantation of transmitters are also presented. These data are presented to support the collaborative, interagency analysis and reporting of the study findings.

  5. Printed-Circuit Cross-Slot Antenna

    NASA Technical Reports Server (NTRS)

    Foy, Wong; Chung, Hsien-Hsien; Peng, Sheng Y.

    1990-01-01

    Coupling between perpendicular slots suppressed. Balanced feed configuration minimizes coupling between slots of printed-circuit cross-slot antenna unit. Unit and array have conventional cavity-backed-printed-circuit, crossed-slot antenna design. Strip-line feeders behind planar conductive antenna element deliver power to horizontal slot in opposite phase. As result, little or no power propagates into vertical slot. Similar considerations apply to strip lines that feed vertical slot. Units of this type elements of phased-array antennas for radar, mobile/satellite communications, and other applications requiring flush mounting and/or rapid steering of beams with circular polarization.

  6. The Dalles Dam juvenile bypass electrical systems

    SciTech Connect

    Bannister, B.D.; Luck, B.

    1995-12-31

    The Corps of Engineers is in the process of providing a juvenile fish bypass system at The Dalles Lock and Dam project on the lower Columbia River. This system is intended to preserve and enhance the dwindling stocks of wild anadromous fish. The impact of the proposed facilities on the electrical systems and on plant operations are developed along with descriptions of the special bypass features including the incorporation of provisions for a future small hydropower generator.

  7. Coronary Artery Bypass Grafting

    MedlinePlus

    ... from the NHLBI on Twitter. What Is Coronary Artery Bypass Grafting? Coronary artery bypass grafting (CABG) is ... bypass multiple coronary arteries during one surgery. Coronary Artery Bypass Grafting Figure A shows the location of ...

  8. Ground-slot waveguide laser

    SciTech Connect

    Chenausky, P.; Drinkwater, E.H.; Laughman, L.M.

    1985-03-18

    A method of fabricating CO/sub 2/ waveguide-type lasers of the type comprising a slot formed in a broad surface of a hard ceramic material, comprising grinding the slot in a conventional surface grinding machine in two steps. The first step utilizes a coarse grinding wheel and the second a finer grinding wheel. The resultant laser cavity can produce high optical-power output when provided with RF excitation.

  9. Experiments on a Slotted Wing

    NASA Technical Reports Server (NTRS)

    Ruden, P

    1939-01-01

    The results of pressure distribution measurements that were made on a model wing section of a Fieseler F 5 R type airplane are presented. Comparison of those model tests with the corresponding flight tests indicates the limitations and also the advantages of wind tunnel investigations, the advantages being particularly that through the variety of measuring methods employed the more complicated flow conditions may also be clarified. A fact brought out in these tests is that even in the case of "well rounded" slots it is possible for a vortex to be set up at the slot entrance and this vortex is responsible for certain irregularities in the pressure distribution and in the efficiency of the slot.

  10. Slotted Antenna with Uniaxial Dielectric Covering

    DTIC Science & Technology

    2016-07-08

    1 of 12 SLOTTED ANTENNA WITH UNIAXIAL DIELECTRIC COVERING STATEMENT OF GOVERNMENT INTEREST [0001] The invention described herein may be...therefor. CROSS REFERENCE TO OTHER PATENT APPLICATIONS [0002] None. BACKGROUND OF THE INVENTION (1) Field of the Invention [0003] The present... invention is directed to a slotted antenna having enhanced broadband characteristics. (2) Description of the Prior Art [0004] Slotted cylinder antennas

  11. Dispersion compensation in slot photonic crystal waveguide

    NASA Astrophysics Data System (ADS)

    Plastun, Alexander; Konyukhov, Andrey

    2015-03-01

    Dispersion tailoring using photonic crystal cladding for slot waveguide is proposed. Numerical modeling based on the Maxwell equation for Te and TM modes of the photonic crystal is performed. Slot waveguide provide high intencity at the central area. Photonic crystal cladding of the slot waveguide allow us to compensate high values of the host glass dispersion.

  12. Drilling Precise Orifices and Slots

    NASA Technical Reports Server (NTRS)

    Richards, C. W.; Seidler, J. E.

    1983-01-01

    Reaction control thrustor injector requires precisely machined orifices and slots. Tooling setup consists of rotary table, numerical control system and torque sensitive drill press. Components used to drill oxidizer orifices. Electric discharge machine drills fuel-feed orifices. Device automates production of identical parts so several are completed in less time than previously.

  13. Slotted Antenna with Anisotropic Covering

    DTIC Science & Technology

    2015-08-06

    below identified patent application is available for licensing. Requests for information should be addressed to: TECHNOLOGY PARTNERSHIP ENTERPRISE...OTHER PATENT APPLICATIONS [0002] None. BACKGROUND OF THE INVENTION (1) Field of the Invention [0003] The present invention is directed to a slotted

  14. Gastric bypass surgery - discharge

    MedlinePlus

    Bariatric surgery - gastric bypass - discharge; Roux-en-Y gastric bypass - discharge; Gastric bypass - Roux-en-Y - discharge; Obesity ... Gloy VL, Briel M, Bhatt DL, et al. Bariatric surgery versus non-surgical treatment for obesity: a systematic ...

  15. Evaluation of the fish passage effectiveness of the Bonneville I prototype surface collector using three-dimensional ultrasonic fish tracking - Final Report

    USGS Publications Warehouse

    Faber, D.M; Weiland, M.A.; Moursund, R.A.; Carlson, T.J.; Adams, N.; Rondorf, D.

    2001-01-01

    This report describes tests conducted at Bonneville Dam on the Columbia River in the spring of 2000. The studies used three-dimensional (3D) acoustic telemetry and computational fluid dynamics (CFD) hydraulic modeling techniques to evaluate the response of outmigrating juvenile steelhead (Oncorhynchus mykiss) and yearling chinook (O. tshawytscha) to the Prototype Surface Collector (PSC) installed at Powerhouse I of Bonneville Dam in 1998 to test the concept of using a deep-slot surface bypass collector to divert downstream migrating salmon from turbines. The study was conducted by Pacific Northwest National Laboratory (PNNL), the Waterways Experiment Station of the U.S. Army Corp of Engineers (COE), Asci Corporation, and the U.S. Geological Survey (USGS), and was sponsored by COE’s Portland District. The goal of the study was to observe the three-dimensional behavior of tagged fish (fish bearing ultrasonic micro-transmitters) within 100 meters (m) of the surface flow bypass structure to test hypotheses about the response of migrants to flow stimuli generated by the presence of the surface flow bypass prototype and its operation. Research was done in parallel with radio telemetry studies conducted by USGS and hydroacoustic studies conducted by WES & Asci to evaluate the prototype surface collector.

  16. Introducing a [open quote]modular[close quote] approach to fish screen installation

    SciTech Connect

    Taft, E.P.; Winchell, F.C.; Cook, T.C.; Sullivan, C.W.

    1992-12-01

    A new fish screen design-the modular inclined screen-promises to offer a versatile and cost-effective solution for fish protection in many situation. In an effort to provide the hydroelectric industry with more cost-effective alternatives to existing fish screen designs, the Electric Power Research Institute (EPRI) recently has undertaken several research projects. One focus of EPRI's research has been on the development and testing of high-velocity fish screens. This program has led to the development of a new screening concept, which shows promise for providing effective protection for a wide range of fish species at hydro plants, steam generating facilities, and irrigation diversions. The concept, known as the Modular Inclined Screen (MIS), currently is being evaluated in laboratory studies prior to field application. The screen is of [open quotes]modular[close quotes] design so as to provide the flexibility necessary for application at a broad range of water intakes. The module is suitable for installation in penstocks, canals, and head pond intakes. The MIS module consists of an entrance with a trashrack, dewatering stoplog slots, an inclined wedgewire screen set at a shallow angle of 10 to 20 degrees to the flow, and a bypass for diverting fish to a transport pipe. The screen is mounted on a pivot shaft so that it can be cleaned via rotation and backflushing. The module is completely enclosed, and is designed to operate at water velocities ranging from 2 to 10 feet per second depending on the fish species and life stages to be protected. Laboratory studies are under way to evaluate the design configuration that yields the best hydraulic conditions for safe fish passage, and the biological effectiveness of this design in diverting selected fish species to the bypass.

  17. Slotted antenna waveguide plasma source

    NASA Technical Reports Server (NTRS)

    Foster, John (Inventor)

    2007-01-01

    A high density plasma generated by microwave injection using a windowless electrodeless rectangular slotted antenna waveguide plasma source has been demonstrated. Plasma probe measurements indicate that the source could be applicable for low power ion thruster applications, ion implantation, and related applications. This slotted antenna plasma source invention operates on the principle of electron cyclotron resonance (ECR). It employs no window and it is completely electrodeless and therefore its operation lifetime is long, being limited only by either the microwave generator itself or charged particle extraction grids if used. The high density plasma source can also be used to extract an electron beam that can be used as a plasma cathode neutralizer for ion source beam neutralization applications.

  18. Dual Mode Slotted Monopole Antenna

    DTIC Science & Technology

    2017-01-05

    perpendicularly from the ground plane and is electrically insulated therefrom. The Attorney Docket No. 300104 5 of 15 first conductor can be...38 provides a support structure for conductive foil 40 and insulates cylinder 32 from foil 40. Disk 38 could be another structure such as a...44A and 44B. First element 44A is insulated from conductive foil 40 and joined to cylinder 32 on a first side of slot 34 at one end of cylinder 32

  19. Portable Slot-Sizing Tool

    NASA Technical Reports Server (NTRS)

    Zuver, Nelson T.

    1987-01-01

    Portable milling tool consisting of air-motor-driven cutter held in adjustable moving slide made possible local removal of chromium plating in close-tolerance, onsite remachining and sizing of half-hole slots on longeron bridges. Made from commercially available parts, including air motor capable of variable speeds up to 900 rpm, ball end mill, revolving handle, two miter gears, and ball slide. Adaptation of portable sizing tool useful for field modification of such large equipment as trucks, aircraft, and ships.

  20. Optical slot antenna and its application

    NASA Astrophysics Data System (ADS)

    Park, Yeonsang; Kim, Jineun; Roh, Young-Geun; Park, Q.-Han

    2017-02-01

    We present an optical slot antenna and its application. By measuring transmission spectra and far-field radiation pattern of metallic slots with nanometer scale, we show that a metallic nanoslot has the properties of an antenna, which are resonance, polarization, and bidirectional far-field radiation pattern, and can be regarded as a magnetic dipole in optical region. Additionally, we also make the unidirectional radiation by adapting the geometry of RF Yagi-Uda antenna and applying slot antenna. By the aid of phase analysis based on 3-dimensional finite-difference time-domain simulation, we can increase the front-to-back ratio of an optical slot Yagi-Uda antenna up to about 5. As the application of a slot antenna, we integrate a metal-insulator-metal plasmonic waveguide with a slot antenna. A surface plasmon waveguide mode propagating in MIM structure is well-coupled to a slot antenna and radiates into free-space in form of dipole radiation. By adding an auxiliary structure that has the role of reflector as like a slot Yagi-Uda antenna, the direction of radiation from a slot antenna integrated with a plasmonic waveguide can be controlled efficiently. Besides the possibility of integration with a waveguide, we expect that a slot antenna can be applied to active devices such as light emitting diodes or lasers for the future.

  1. Polymer and composite polymer slot waveguides

    NASA Astrophysics Data System (ADS)

    Hiltunen, Marianne; Fegadolli, William S.; Lira, Hugo L. R.; Vahimaa, Pasi; Hiltunen, Jussi; Aikio, Sanna; Almeida, Vilson R.; Karioja, Pentti

    2014-05-01

    A fully polymer slot Young interferometer operating at 633 nm wavelength was fabricated by using nanoimprint molding method. The phase response of the interference pattern was measured with several concentrations of glucose-water solutions, utilizing both TE and TM polarization states. The sensor was experimentally found to detect a bulk refractive index change of 6.4×10-6 RIU. Temperature dependency of silicon slot waveguide has been demonstrated to be reduced with composite slot waveguide structure. The slot filled with thermally stable polymer having negative thermo-optic coefficient showed nearly an athermal operation of silicon slot waveguide. Experimental results show that the slot waveguide geometry covered with Ormocomp has thermo-optical coefficient of 6 pm/K.

  2. Polymeric slot waveguide for photonics sensing

    NASA Astrophysics Data System (ADS)

    Chovan, J.; Uherek, F.

    2016-12-01

    Polymeric slot waveguide for photonics sensing was designed, simulated and studied in this work. The polymeric slot waveguide was designed on commercial Ormocer polymer platform and operates at visible 632.8 nm wavelength. Designed polymeric slot waveguide detects the refractive index change of the ambient material by evanescent field label-free techniques. The motivation for the reported work was to design a low-cost polymeric slot waveguide for sensing arms of integrated Mach-Zehnder interferometer optical sensor with reduced temperature dependency. The minimal dimensions of advanced sensing slot waveguide structure were designed for researcher direct laser writing fabrication by nonlinear two-photon polymerization. The normalized effective refractive index changes of TE and TM fundamental modes in polymeric slot waveguide and slab waveguides were compared. The sensitivity of the normalized effective refractive index changes of TE and TM fundamental modes on refractive index changes of the ambient material was investigated by glucose-water solutions.

  3. Coupling impedance of a long slot and an array of slots in a circular vacuum chamber

    SciTech Connect

    Stupakov, G.V.

    1995-06-01

    We find the real part of the longitudinal impedance for both a small hole and a long slot in a beam vacuum chamber with a circular cross section. The slot can be arbitrarily long; the only requirement on the dimensions of the slots is that its width be much smaller than c/w. Regular array of N slots periodically distributed along the pipe is also considered.

  4. Slot injection for skin-friction drag reduction

    NASA Technical Reports Server (NTRS)

    Cary, A. M., Jr.; Bushnell, D. M.; Hefner, J. N.

    1977-01-01

    A description and analysis of slot injection in low-speed flow, slot injection in high-speed flow, a discussion of aircraft applications, and possibilities for future improvements of slot drag reduction capability are presented.

  5. Radiation pattern analysis of the tapered slot antenna, appendix 1

    NASA Technical Reports Server (NTRS)

    Janaswamy, Ramakrishna

    1986-01-01

    A theoretical model for the tapered slot antenna is presented. The model is valid for any smooth taper of the slot. The problem is solved by modeling the slot electric field and using the half plane Green's function to compute the far fields. The aperture field is obtained by affecting a stepped approximation to the continuous taper and utilizing the uniform wide slot line data. The uniform wide slot line is solved by the spectral Galerkin's technique and closed form experssions are developed for the slot wave length and the slot characteristic impedance. Numerous comparisons with measurement are made to demonstrate the versatility of the model in treating an arbitrary slot taper.

  6. Peripheral artery bypass - leg

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/007394.htm Peripheral artery bypass - leg To use the sharing features on this page, please enable JavaScript. Peripheral artery bypass is surgery to reroute the blood supply ...

  7. Electrically Small Folded Slot Antenna Utilizing Capacitive Loaded Slot Lines

    NASA Technical Reports Server (NTRS)

    Scardelletti, Maximilian C.; Ponchak, George E.; Merritt, Shane; Minor, John S.; Zorman, Christian A.

    2007-01-01

    This paper presents an electrically small, coplanar waveguide fed, folded slot antenna that uses capacitive loading. Several antennas are fabricated with and without capacitive loading to demonstrate the ability of this design approach to reduce the resonant frequency of the antenna, which is analogous to reducing the antenna size. The antennas are fabricated on Cu-clad Rogers Duriod(TM) 6006 with multilayer chip capacitors to load the antennas. Simulated and measured results show close agreement, thus, validating the approach. The electrically small antennas have a measured return loss greater than 15 dB and a gain of 5.4, 5.6, and 2.7 dBi at 4.3, 3.95, and 3.65 GHz, respectively.

  8. Patients undergoing elective coronary artery bypass grafting exhibit poor pre-operative intakes of fruit, vegetables, dietary fibre, fish and vitamin D.

    PubMed

    Ruiz-Núñez, B; van den Hurk, G H A M; de Vries, J H M; Mariani, M A; de Jongste, M J L; Dijck-Brouwer, D A J; Muskiet, F A J

    2015-05-14

    CHD may ensue from chronic systemic low-grade inflammation. Diet is a modifiable risk factor for both, and its optimisation may reduce post-operative mortality, atrial fibrillation and cognitive decline. In the present study, we investigated the usual dietary intakes of patients undergoing elective coronary artery bypass grafting (CABG), emphasising on food groups and nutrients with putative roles in the inflammatory/anti-inflammatory balance. From November 2012 to April 2013, we approached ninety-three consecutive patients (80% men) undergoing elective CABG. Of these, fifty-five were finally included (84% men, median age 69 years; range 46-84 years). The median BMI was 27 (range 18-36) kg/m(2). The dietary intake items were fruits (median 181 g/d; range 0-433 g/d), vegetables (median 115 g/d; range 0-303 g/d), dietary fibre (median 22 g/d; range 9-45 g/d), EPA+DHA (median 0.14 g/d; range 0.01-1.06 g/d), vitamin D (median 4.9 μg/d; range 1.9-11.2 μg/d), saturated fat (median 13.1% of energy (E%); range 9-23 E%) and linoleic acid (LA; median 6.3 E%; range 1.9-11.3 E%). The percentages of patients with dietary intakes below recommendations were 62% (fruits; recommendation 200 g/d), 87 % (vegetables; recommendation 150-200 g/d), 73% (dietary fibre; recommendation 30-45 g/d), 91% (EPA+DHA; recommendation 0.45 g/d), 98% (vitamin D; recommendation 10-20 μg/d) and 13% (LA; recommendation 5-10 E%). The percentages of patients with dietary intakes above recommendations were 95% (saturated fat; recommendation < 10 E%) and 7% (LA). The dietary intakes of patients proved comparable with the average nutritional intake of the age- and sex-matched healthy Dutch population. These unbalanced pre-operative diets may put them at risk of unfavourable surgical outcomes, since they promote a pro-inflammatory state. We conclude that there is an urgent need for intervention trials aiming at rapid improvement of their diets to reduce peri-operative risks.

  9. A design procedure for a slotted waveguide with probe-fed slots radiating into plasma

    SciTech Connect

    Colborn, J.A.

    1989-11-01

    A design procedure is developed for slotted-waveguide antennas with probe-fed slots. Radiation into a gyrotropic, plane-stratified medium is considered, nonzero waveguide wall thickness is assumed, and noncosinusoidal slot fields and arbitrary slot length up to about one free-space wavelength are allowed. External mutual coupling is taken into account by matching the tangential fields at the antenna surface. The particular case of longitudinal slots in the broad face of rectangular guide is analyzed. The motivation for this work is the design of such radiators for plasma heating and current-drive on thermonuclear fusion experiments, but some of the analysis is applicable to the probeless slotted waveguide used for avionics and communications. 20 refs., 5 figs.

  10. Slot synchronization in optical PPM communications

    NASA Astrophysics Data System (ADS)

    Ling, Ger; Gagliardi, Robert M.

    1986-12-01

    Maintaining slot clock synchronization in a baseband pulse position modulated (PPM) communication link is vital to its performance. This paper examines the slot clocking design associated with a direct detection, photodetecting optical PPM system. Although theoretical PPM synchronizers for optical links have been derived in the past, there is still interest in finding more practical, simpler, and easier-to-implement clocking subsystems. In this paper several types of practical slot synchronizers are considered. A basic design involving analog correlators and slot gating is presented, along with an indication of its performance. Several alternative designs are also presented, including digital synchronizers in which time samples are used for loop control. The advantage in digital systems is that more extensive processing can be handled in software, allowing the loop to perform closer to the ideal. Design procedures for digital clocking are presented, and optimal laser pulse shaping and filtering are discussed. Performance in terms of loop models and tracking error variance is included.

  11. VHF Injector Pumping Slot RF Shielding Effectiveness

    SciTech Connect

    Staples, John

    2007-08-08

    The effectiveness of the shielding of the pumping slots is calculated for two radial depths of the slots with Mafia-2 and compared to a simple recipe that calculates the RF attenuation in a slot. CBP Technical Note 378 describes the pumping configuration of the 100 MHz VHF photoinjector. The cavity is surrounded by 36 slots, 4.9 cm wide, separated by bars, also 4.9 cm wide. The radial depth of the bars controls the attenuation of the RF from the cavity proper to the annular plenum outside the bars where the getter pumps are located. This note describes calculations of the level of RF fields in the plenum for two different values of the radial depth of the bars and two different values of the spacing between the outer dimension of the bars and the outer plenum wall.

  12. Flattened dispersion in silicon slot waveguides.

    PubMed

    Zhang, Lin; Yue, Yang; Beausoleil, Raymond G; Willner, Alan E

    2010-09-13

    We propose a silicon strip/slot hybrid waveguide that produces flattened dispersion of 0 ± 16 ps/(nm∙km), over a 553-nm wavelength range, which is 20 times flatter than previous results. Different from previously reported slot waveguides, the strip/slot hybrid waveguide employs the mode transition from a strip mode to a slot mode to introduce unique waveguide dispersion. The flat dispersion profile is featured by three zero-dispersion wavelengths, which is obtained for the first time in on-chip silicon waveguides, to the best of our knowledge. The waveguide exhibits flattened dispersion from 1562-nm to 2115-nm wavelength, which is potentially useful for both telecom and mid-infrared applications.

  13. Modified Withdrawal Slot Increases Silicon Production

    NASA Technical Reports Server (NTRS)

    Piotrowsky, P. A.; Duncan, C. S.

    1988-01-01

    New shape reduces ribbon breakage and resulting idle time. Shape for slot through which single-crystal silicon ribbon pulled from melt increases productivity. Reduces tendency of emerging ribbon to grow thin and break.

  14. Bypass system modification at Bonneville Dam on the Columbia River improved the survival of juvenile salmon

    USGS Publications Warehouse

    Ferguson, J.W.; Sandford, B.P.; Reagan, R.E.; Gilbreath, L.G.; Meyer, E.B.; Ledgerwood, R.D.; Adams, N.S.

    2007-01-01

    From 1987 to 1992, we evaluated a fish bypass system at Bonneville Dam Powerhouse 2 on the Columbia River. The survival of subyearling Chinook salmon Oncorhynchus tshawytscha released into the system ranged from 0.774 to 0.911 and was significantly lower than the survival of test fish released into turbines and the area immediately below the powerhouse where bypass system flow reentered the river. Yearling and subyearling Chinook salmon and yearling coho salmon O. kisutch released into the bypass system were injured or descaled. Also, levels of blood plasma cortisol and lactate were significantly higher in yearling and subyearling Chinook salmon that passed through the bypass system than in fish released directly into a net located over the bypass exit. This original system was then extensively modified using updated design criteria, and the site where juvenile fish reentered the river was relocated 2.8 km further downstream to reduce predation on bypassed fish by northern pikeminnow Ptychocheilus oregonensis. Based on studies conducted from 1999 to 2001, the new bypass system resulted in high fish survival, virtually no injuries to fish, fish passage times that were generally similar to water travel times, and mild stress responses from which fish recovered quickly. The mean estimated survival of subyearling Chinook salmon passing through the new bypass system was 0.946 in 2001, which was an usually low-flow year. Survival, physical condition, passage timing, and blood physiological indicators of stress were all useful metrics for assessing the performance of both bypass systems and are discussed. The engineering and hydraulic criteria used to design the new bypass system that resulted in improved fish passage conditions are described.

  15. Slotted Polyimide-Aerogel-Filled-Waveguide Arrays

    NASA Technical Reports Server (NTRS)

    Rodriguez-Solis, Rafael A.; Pacheco, Hector L.; Miranda, Felix A.; Meador, Mary Ann B.

    2013-01-01

    This presentation discussed the potential advantages of developing Slotted Waveguide Arrays using polyimide aerogels. Polyimide (PI) aerogels offer great promise as an enabling technology for lightweight aerospace antenna systems. PI aerogels are highly porous solids possessing low density and low dielectric permittivity combined with good mechanical properties. For slotted waveguide array applications, there are significant advantages in mass that more than compensate for the slightly higher loss of the aerogel filled waveguide when compared to state of practice commercial waveguide.

  16. Irrational thinking among slot machine players.

    PubMed

    Walker, M B

    1992-09-01

    According to the cognitive perspective on gambling, regular gamblers persist in trying to win money at gambling because they hold a set of false beliefs about the nature of gambling, the likelihood of winning, and their own expertise. In order to investigate this claim, twenty seven university students were recruited who played one of three types of games at least twice a week: slot machines, video draw poker, and video amusement games. Subjects played their preferred machines on site (clubs, hotels and amusement arcades) first for at least thirty minutes and then the other two games for a minimum of twenty minutes each. During play, each subject spoke aloud into a microphone describing what he or she was doing or thinking about in the game. It was hypothesised that slot machine players would verbalise more irrational thinking than video poker or video amusement players and that slot machines would elicit more irrational thinking than video poker or video amusement machines. Most importantly, it was hypothesised that slot machine players would exhibit relatively greater amounts of irrational thinking when playing their preferred game. The data supported all three hypotheses. Out of all of the statements made by slot machine players when playing slot machines, 38% were categorised irrational. Furthermore, 80% of the strategic statements made by slot machine players while playing slot machines were categorised as irrational. These results are consistent with earlier work which showed high levels of irrational thinking in artificial gambling games. Together, the results provide support for a cognitive view of the origins of gambling problems.

  17. Slotted photonic crystals for biosensing applications

    NASA Astrophysics Data System (ADS)

    Scullion, M. G.; Krauss, T. F.; Di Falco, A.

    2012-06-01

    We discuss the properties and potential of slotted photonic crystals devices as small optical, label-free biosensors. This approach combines slot waveguides, which guide light in a narrow air slot, with photonic crystals in which cavities and slow light behaviour can be engineered. We use cavities based upon the heterostructure approach, demonstrating experimental quality factors of up to 50,000 in air and 4,000 in water. As the peak of the cavity mode interacts with the contents of the slot, small changes in refractive index can be inferred from the cavity resonant wavelength with high sensitivity (~500 nm/RIU). We also integrate microfluidic channels, which when combined with the small footprint of each sensor, allows potential for dense multiplexing with only micro-litres of analyte. As the dispersive properties of the fundamental mode of a standard and slotted photonic crystal differ greatly, a suitable interface for coupling into the device must be found. We here utilise a resonant defect approach, which preferentially couples into the slot mode. Functionalising the surface of the device with antibodies allows us to detect specific binding of a target protein on the sensor surface. As a proof of principle demonstration we show detection of dissolved avidin concentrations as low as 15 nM using biotin functionalised devices.

  18. Coronary–Coronary Bypass

    PubMed Central

    Erdil, Nevzat; Ates, Sanser; Demirkilic, Ufuk; Tatar, Harun; Sag, Cemal

    2002-01-01

    There is increased risk of systemic embolism during cardiopulmonary bypass in patients with a severely atherosclerotic ascending aorta. We report a coronary–coronary bypass in a 74-year-old man with a porcelain aorta. He underwent a proximal right coronary–distal right coronary artery bypass with a saphenous vein graft, combined with a pedicled arterial graft (left internal mammary artery) to the left anterior descending artery, in the presence of a beating heart without cardiopulmonary bypass. The patient survived without evidence of perioperative myocardial infarction or cerebrovascular accident. One year later, follow-up angiography showed graft patency with good distal runoff. Coronary–coronary bypass on a beating heart without cardiopulmonary bypass can be performed safely in a patient with porcelain aorta. (Tex Heart Inst J 2002;29:54–5) PMID:11995853

  19. A rapid chemiluminescent slot blot immunoassay for the detection and quantification of Clostridium botulinum neurotoxin type E, in cultures.

    PubMed

    Cadieux, Brigitte; Blanchfield, Burke; Smith, James P; Austin, John W

    2005-05-01

    A simple, rapid, cost-effective in vitro slot blot immunoassay was developed for the detection and quantification of botulinum neurotoxin type E (BoNT/E) in cultures. Culture supernatants of 36 strains of clostridia, including 12 strains of Clostridium botulinum type E, 12 strains of other C. botulinum neurotoxin serotypes, and 12 strains of other clostridial species were tested. Samples containing BoNT/E were detected using affinity-purified polyclonal rabbit antisera prepared against BoNT/E with subsequent detection of secondary antibodies using chemiluminescence. All strains of C. botulinum type E tested positive, while all non C. botulinum type E strains tested negative. The sensitivity of the slot blot immunoassay for detection of BoNT/E was approximately four mouse lethal doses (MLD). The intensity of chemiluminescence was directly correlated with the concentration of BoNT/E up to 128 MLD, allowing quantification of BoNT/E between 4 and 128 MLD. The slot blot immunoassay was compared to the mouse bioassay for detection of BoNT/E using cultures derived from fish samples inoculated with C. botulinum type E, and cultures derived from naturally contaminated environmental samples. A total of 120 primary enrichment cultures derived from fish samples, of which 103 were inoculated with C. botulinum type E, and 17 were uninoculated controls, were assayed. Of the 103 primary enrichment cultures derived from inoculated fish samples, all were positive by mouse bioassay, while 94 were also positive by slot blot immunoassay, resulting in a 7.5% false-negative rate. All 17 primary enrichment cultures derived from the uninoculated fish samples were negative by both mouse bioassay and slot blot immunoassay. A total of twenty-six primary enrichment cultures derived from environmental samples were tested by mouse bioassay and slot blot immunoassay. Of 13 primary enrichment cultures positive by mouse bioassay, 12 were also positive by slot blot immunoassay, resulting in a 3

  20. Heart bypass surgery

    MedlinePlus Videos and Cool Tools

    Heart bypass surgery begins with an incision made in the chest, with the breastbone cut exposing the heart. Next, a portion of the saphenous vein is ... used to bypass the blocked arteries in the heart. The venous graft is sewn to the aorta ...

  1. Stereoscopic display in a slot machine

    NASA Astrophysics Data System (ADS)

    Laakso, M.

    2012-03-01

    This paper reports the results of a user trial with a slot machine equipped with a stereoscopic display. The main research question was to find out what kind of added value does stereoscopic 3D (S-3D) bring to slot games? After a thorough literature survey, a novel gaming platform was designed and implemented. Existing multi-game slot machine "Nova" was converted to "3DNova" by replacing the monitor with an S-3D display and converting six original games to S-3D format. To evaluate the system, several 3DNova machines were put available for players for four months. Both qualitative and quantitative analysis was carried out from statistical values, questionnaires and observations. According to the results, people find the S-3D concept interesting but the technology is not optimal yet. Young adults and adults were fascinated by the system, older people were more cautious. Especially the need to wear stereoscopic glasses provide a challenge; ultimate system would probably use autostereoscopic technology. Also the games should be designed to utilize its full power. The main contributions of this paper are lessons learned from creating an S-3D slot machine platform and novel information about human factors related to stereoscopic slot machine gaming.

  2. Throat-bypass bleed systems for increasing the stable airflow range of a Mach 2.50 axisymmetric inlet with 40-percent internal contraction

    NASA Technical Reports Server (NTRS)

    Sanders, B. W.; Mitchell, G. A.

    1973-01-01

    The results of an experimental investigation to increase the stable airflow range of a super sonic mixed-compression inlet are presented. Various throat-bypass bleeds were located on the inlet cowl. The bleed types were distributed porous normal holes, a forward slanted slot, or distributed educated slots. Large inlet stability margins were obtained with the inlet throat bleed systems if a constant pressure was maintained in the throat-bypass bleed plenum. Stability limits were determined for steady-state and limited transient internal air flow changes. Limited unstart angle-of-attack data are presented.

  3. Productivity of Noun Slots in Verb Frames.

    PubMed

    Theakston, Anna L; Ibbotson, Paul; Freudenthal, Daniel; Lieven, Elena V M; Tomasello, Michael

    2015-08-01

    Productivity is a central concept in the study of language and language acquisition. As a test case for exploring the notion of productivity, we focus on the noun slots of verb frames, such as __want__, __see__, and __get__. We develop a novel combination of measures designed to assess both the flexibility and creativity of use in these slots. We do so using a rigorously controlled sample of child speech and child directed speech from three English-speaking children between the ages of 2-3 years and their caregivers. We find different levels of creativity and flexibility between the adult and child samples for some measures, for some slots, and for some developmental periods. We discuss these differences in the context of verb frame semantics, conventionality versus creativity and child errors, and draw some tentative conclusions regarding developmental changes in children's early grammatical representations. © 2015 Cognitive Science Society, Inc.

  4. Slotted Polyimide-Aerogel-Filled-Waveguide Arrays

    NASA Technical Reports Server (NTRS)

    Rodriguez-Solis, Rafael A.; Pacheco, Hector L.; Miranda, Felix A.; Meador, Mary Ann B.

    2013-01-01

    Polyimide aerogels were considered to serve as a filling for millimeter-wave waveguides. While these waveguides present a slightly higher loss than hollow waveguides, they have less losses than Duroid substrate integrated waveguides (less than 0.15 dB at Ka-band, in a 20 mm section), and exhibit an order of magnitude of mass reduction when compared to commercial waveguides. A Ka-band slotted aerogel-filled-waveguide array was designed, which provided the same gain (9 dBi) as its standard waveguide counterpart, and a slotted aerogel-filled-waveguide array using folded-slots was designed for comparison, obtaining a gain of 9 dB and a bandwidth of 590 MHz.

  5. [SLOT Scan imaging in teenagers with scoliosis].

    PubMed

    Situ, Weijun; Li, Yajun; Li, Zuohua; Hu, Zhongjun; He, Jian

    2009-07-01

    To explore the improvement effect of SLOT Scan technology (narrow seam exposure capture technology) and the radiography techniques on the quality of the scoliosis X-ray films in teenagers. The Sonialvision Safire II equipment of Shimadzu corporation and SLOT Scan were applied to take the radiography for 60 patients taller than 1.50 metres. All the data were collected through a continual exposure, and the images were sewn up through a seamless connection software. Cervical, thoracic, and lumbar and sacral segments could clearly present at the same time on one X-ray film by seamless splicing,and the quality of one time radiograph was as good as one film. As a new radiology technique, SLOT Scan can wipe off splitting artifact effectively and make the whole spine seamless present on one X-ray film. It helps the spinal surgeons to observe, calculate and measure accurately. It is useful to choose the operation mode and judge the curative effect.

  6. Microlayer during boiling in narrow slot channels

    NASA Astrophysics Data System (ADS)

    Diev, Mikhail D.; Leontiev, Alexander I.

    1997-01-01

    An international space station Alpha will have a two-phase thermal control system. Boiling of a liquid ammonia will be a process of heat collection in evaporative heat exchangers. Unfortunately, only little data is available for boiling heat transfer in microgravity. Geometries of boiling channels working good in normal gravity are not appropriate in microgravity, and special means should be worked out to avoid some undesired events. From this point of view, the narrow slot channels may be assumed as a promising geometry for microgravity operation. During boiling in narrow slots, the vapor bubbles are flattened between the channel walls. The vapor phase and the channel wall are separated by a thin liquid film which is known as a microlayer. The paper presents the experimental results compared to the theoretical analysis, the paper also shows the narrow slot channels as a perspective configuration for microgravity applications.

  7. Polymeric slot waveguide interferometer for sensor applications.

    PubMed

    Hiltunen, Marianne; Hiltunen, Jussi; Stenberg, Petri; Aikio, Sanna; Kurki, Lauri; Vahimaa, Pasi; Karioja, Pentti

    2014-03-24

    A refractive index sensor based on slot waveguide Young interferometer was developed in this work. The interferometer was fabricated on a polymer platform and operates at a visible wavelength of 633 nm. The phase shift of the interference pattern was measured with various concentrations of glucose-water solutions, utilizing both TE and TM polarization states. The sensor was experimentally observed to detect a refractive index difference of 6.4 × 10(-6) RIU. Furthermore, the slot Young interferometer was found to compensate for temperature variations. The results of this work demonstrate that high performance sensing capability can be obtained with a polymeric slot Young interferometer, which can be fabricated by a simple molding process.

  8. Coupling impedance of a long slot and an array of slots in a circular vacuum chamber

    SciTech Connect

    Stupakov, G.V.

    1995-04-01

    A method is presented for calculating the real part of the longitudinal impedance {ital Z} at a frequency {omega} for both a small hole and a long slot in a beam vacuum chamber with a circular cross section. The length of the slot can be arbitrarily large; the only requirement of the dimensions of the slots is that its width be much smaller than {ital c}/{omega}. Regular arrays of {ital N} slots periodically distributed along the pipe are also considered. The equation relating the real part of the impedance to the energy radiated by the slot into waveguide eigenmodes is the basis of this method. We show that in addition to broadband impedance, there are narrow peaks in Re{ital Z}. For a single slot, the peaks are located slightly above the cutoff frequencies of various waveguide modes. For a periodic array, additional peaks are generated at frequencies determined by the array period. These peaks can be partially suppressed by randomization of the positions of the slots.

  9. High slot utilization systems for electric machines

    DOEpatents

    Hsu, John S

    2009-06-23

    Two new High Slot Utilization (HSU) Systems for electric machines enable the use of form wound coils that have the highest fill factor and the best use of magnetic materials. The epoxy/resin/curing treatment ensures the mechanical strength of the assembly of teeth, core, and coils. In addition, the first HSU system allows the coil layers to be moved inside the slots for the assembly purpose. The second system uses the slided-in teeth instead of the plugged-in teeth. The power density of the electric machine that uses either system can reach its highest limit.

  10. Endfire tapered slot antennas on dielectric substrates

    NASA Technical Reports Server (NTRS)

    Yngvesson, K. S.; Schaubert, D. H.; Korzeniowski, T. L.; Kollberg, E. L.; Thungren, T.

    1985-01-01

    Endfire-tapered slot antennas are suitable for many integrated circuit applications, imaging and phased arrays. An investigation of single elements of such antennas, including slots which are exponentially tapered (Vivaldi), linearly tapered, and constant width. For antennas of all types, a good general agreement is obtained for curves of beamwidth-versus-length, normalized to wavelength, when one compares the data with that for traveling-wave antennas published by Zucker (1961). An important condition for this agreement is that the effective dielectric thickness, defined in the text, is in a certain optimum range. This condition is qualitatively explained in terms of the theory for traveling-wave antennas.

  11. Downstream influence of swept slot injection in hypersonic turbulent flow

    NASA Technical Reports Server (NTRS)

    Hefner, J. N.; Cary, A. M., Jr.; Bushnell, D. B.

    1977-01-01

    Results of an experimental and numerical investigation of tangential swept slot injection into a thick turbulent boundary layer at Mach 6 are presented. Film cooling effectiveness, skin friction, and flow structure downstream of the swept slot injection were investigated. The data were compared with that for unswept slots, and it was found that cooling effectiveness and skin friction reductions are not significantly affected by sweeping the slot.

  12. Productivity of Noun Slots in Verb Frames

    ERIC Educational Resources Information Center

    Theakston, Anna L.; Ibbotson, Paul; Freudenthal, Daniel; Lieven, Elena V. M.; Tomasello, Michael

    2015-01-01

    Productivity is a central concept in the study of language and language acquisition. As a test case for exploring the notion of productivity, we focus on the noun slots of verb frames, such as __"want"__, __"see"__, and __"get"__. We develop a novel combination of measures designed to assess both the flexibility and…

  13. A 20 GHz Active Receive Slot Array

    NASA Technical Reports Server (NTRS)

    Tulintseff, A. N.; Lee, K.; Sukamto, L.; Chew, W.

    1994-01-01

    A 20 GHz active receive slot array has been developed for operation in the downlink frequency band of NASA's Advanced Communication Technology Satellite (ACTS) for the ACTS Mobile Terminal (AMT) project. The AMT is to demonstrate voice and data communication between a mobile terminal in Los Angeles, California, and a fixed terminal in Cleveland, Ohio, via the ACTS satellite.

  14. Flow Liner Slot Edge Replication Feasibility Study

    NASA Technical Reports Server (NTRS)

    Newman, John A.; Willard, Scott A.; Smith, Stephen W.; Piascik, Robert S.

    2006-01-01

    Surface replication has been proposed as a method for crack detection in space shuttle main engine flowliner slots. The results of a feasibility study show that examination of surface replicas with a scanning electron microscope can result in the detection of cracks as small as 0.005 inch, and surface flaws as small as 0.001 inch, for the flowliner material.

  15. Productivity of Noun Slots in Verb Frames

    ERIC Educational Resources Information Center

    Theakston, Anna L.; Ibbotson, Paul; Freudenthal, Daniel; Lieven, Elena V. M.; Tomasello, Michael

    2015-01-01

    Productivity is a central concept in the study of language and language acquisition. As a test case for exploring the notion of productivity, we focus on the noun slots of verb frames, such as __"want"__, __"see"__, and __"get"__. We develop a novel combination of measures designed to assess both the flexibility and…

  16. A 20 GHz Active Receive Slot Array

    NASA Technical Reports Server (NTRS)

    Tulintseff, A. N.; Lee, K.; Sukamto, L.; Chew, W.

    1994-01-01

    A 20 GHz active receive slot array has been developed for operation in the downlink frequency band of NASA's Advanced Communication Technology Satellite (ACTS) for the ACTS Mobile Terminal (AMT) project. The AMT is to demonstrate voice and data communication between a mobile terminal in Los Angeles, California, and a fixed terminal in Cleveland, Ohio, via the ACTS satellite.

  17. Computational analysis of forebody tangential slot blowing

    NASA Technical Reports Server (NTRS)

    Gee, Ken; Agosta-Greenman, Roxana M.; Rizk, Yehia M.; Schiff, Lewis B.; Cummings, Russell M.

    1994-01-01

    An overview of the computational effort to analyze forebody tangential slot blowing is presented. Tangential slot blowing generates side force and yawing moment which may be used to control an aircraft flying at high-angle-of-attack. Two different geometries are used in the analysis: (1) The High Alpha Research Vehicle; and (2) a generic chined forebody. Computations using the isolated F/A-18 forebody are obtained at full-scale wind tunnel test conditions for direct comparison with available experimental data. The effects of over- and under-blowing on force and moment production are analyzed. Time-accurate solutions using the isolated forebody are obtained to study the force onset timelag of tangential slot blowing. Computations using the generic chined forebody are obtained at experimental wind tunnel conditions, and the results compared with available experimental data. This computational analysis compliments the experimental results and provides a detailed understanding of the effects of tangential slot blowing on the flow field about simple and complex geometries.

  18. Coupling Between Waveguide-Fed Slot Arrays

    NASA Technical Reports Server (NTRS)

    Rengarajan, Sembiam

    2011-01-01

    Coupling between two waveguide-fed planar slot arrays has been investigated using full-wave analysis. The analysis employs the method-of-moments solution to the pertinent coupled integral equations for the aperture electric field of all slots. In order to compute coupling between two arrays, the input port of the first array is excited with a TE(sub 10) mode wave while the second one is match-terminated. After solving the moment method matrix equations, the aperture fields of all slots are obtained and thereby the TE(sub 10) mode wave received at the input port of the second array is determined. Coupling between two arrays is the ratio of the wave amplitude arriving in the second array port to the incident wave amplitude at the first array port. The coupling mechanism has been studied as a function of spacing between arrays in different directions, e.g. the electric field plane, the magnetic field plane, and the diagonal plane. Computed coupling values are presented for different array geometries. This work is novel since it provides a good understanding of coupling between waveguide-fed slot arrays as a function of spacing and orientation for different aperture distributions and array architectures. This serves as a useful tool for antenna design engineers and system engineers.

  19. Gastric Bypass Surgery

    MedlinePlus

    ... much you can eat or by reducing the absorption of nutrients, or both. Gastric bypass and other ... you can eat at one sitting and reducing absorption of nutrients. The surgeon cuts across the top ...

  20. Gastric bypass surgery

    MedlinePlus

    ... your legs to help prevent blood clots from forming. You will receive shots of medicine to prevent ... diversion with duodenal switch Dumping syndrome References Buchwald H. Laparoscopic Roux-en-Y gastric bypass. In: Buchwald ...

  1. Slot antenna SIS mixers for submillimeter wavelengths

    NASA Astrophysics Data System (ADS)

    Zmuidzinas, Jonas; Leduc, Henry G.; Stern, J. A.

    We are developing improved versions of a slot antenna SIS mixer which we have previously described. The initial work demonstrated a double sideband noise temperature of 420 K for a 500 GHz quasi-optical SIS mixer employing a twin-slot antenna on a quartz dielectric substrate. A quartz hyperhemispherical lens is used to focus the incoming radiation onto the twin-slot antenna. The advantages of a twin-slot antenna include a low impedance (35 omega) and a clean, symmetric beam pattern into the dielectric with a 70 percent efficiency. In our original mixer, the radiation was coupled from the two slot antennas onto superconducting microstrip lines which fed the SIS junction. By performing an impedance transformation using tapered lines and by feeding the radiation from the two slots to the junction in parallel, the effective (real) impedance seen by the junction was reduced to just 4 omega. This very low impedance allowed a junction area of 2.3 sq micron to be used at 500 GHz, which was manufactured using optical lithography. However, no attempt was made to tune out the junction capacitance. We estimate that this capacitance reduces the impedance coupling efficiency to eta(sub Z) approx. equals 0.23, for our junction with omega R(sub N) C = 5.3 at 500 GHz. The recent development of techniques using electron-beam lithography to manufacture junctions with very small areas (approx. equals 0.1 sq microns) now allows considerably more flexibility in the design of SIS mixer circuits. We have redesigned the slot-antenna mixer to take advantage of this possibility. In particular, we have included a novel circuit which allows the junction capacitance to be tune out over a broad bandwidth. For instance, mixers designed for 800 GHz using NbN/MgO/NbN junctions with realistic parameters achieve a 3 dB impedance bandwidth of nearly 400 GHz. Furthermore, our circuit uses only short lengths of microstrip and should be less sensitive to RF losses than other designs. The improved

  2. Seizures Following Cardiopulmonary Bypass

    PubMed Central

    Brouwer, Monique E.; McMeniman, William J.

    2016-01-01

    Abstract: Seizures following cardiopulmonary bypass are an immediate and alarming indication that a neurologic event has occurred. A case report of a 67-year-old man undergoing aortic valve surgery who unexpectedly experiences seizures following cardiopulmonary bypass is outlined. Possible contributing factors including atheromatous disease in the aorta, low cerebral perfusion pressures, an open-chamber procedure, and the use of tranexamic acid are identified. PMID:27729707

  3. Aerothermal characteristics of bleed slot in hypersonic flows

    NASA Astrophysics Data System (ADS)

    Yue, LianJie; Lu, HongBo; Xu, Xiao; Chang, XinYu

    2015-10-01

    Two types of flow configurations with bleed in two-dimensional hypersonic flows are numerically examined to investigate their aerodynamic thermal loads and related flow structures at choked conditions. One is a turbulent boundary layer flow without shock impingement where the effects of the slot angle are discussed, and the other is shock wave boundary layer interactions where the effects of slot angle and slot location relative to shock impingement point are surveyed. A key separation is induced by bleed barrier shock on the upstream slot wall, resulting in a localized maximum heat flux at the reattachment point. For slanted slots, the dominating flow patterns are not much affected by the change in slot angle, but vary dramatically with slot location relative to the shock impingement point. Different flow structures are found in the case of normal slot, such as a flow pattern similar to typical Laval nozzle flow, the largest separation bubble which is almost independent of the shock position. Its larger detached distance results in 20% lower stagnation heat flux on the downstream slot corner, but with much wider area suffering from severe thermal loads. In spite of the complexity of the flow patterns, it is clearly revealed that the heat flux generally rises with the slot location moving downstream, and an increase in slot angle from 20° to 40° reduces 50% the heat flux peak at the reattachment point in the slot passage. The results further indicate that the bleed does not raise the heat flux around the slot for all cases except for the area around the downstream slot corner. Among all bleed configurations, the slot angle of 40° located slightly upstream of the incident shock is regarded as the best.

  4. Aerothermal characteristics of bleed slot in hypersonic flows

    NASA Astrophysics Data System (ADS)

    Yue, LianJie; Lu, HongBo; Xu, Xiao; Chang, XinYu

    2015-10-01

    Two types of flow configurations with bleed in two-dimensional hypersonic flows are numerically examined to investigate their aerodynamic thermal loads and related flow structures at choked conditions. One is a turbulent boundary layer flow without shock impingement where the effects of the slot angle are discussed, and the other is shock wave boundary layer interactions where the effects of slot angle and slot location relative to shock impingement point are surveyed. A key separation is induced by bleed barrier shock on the upstream slot wall, resulting in a localized maximum heat flux at the reattachment point. For slanted slots, the dominating flow patterns are not much affected by the change in slot angle, but vary dramatically with slot location relative to the shock impingement point. Different flow structures are found in the case of normal slot, such as a flow pattern similar to typical Laval nozzle flow, the largest separation bubble which is almost independent of the shock position. Its larger detached distance results in 20% lower stagnation heat flux on the downstream slot corner, but with much wider area suffering from severe thermal loads. In spite of the complexity of the flow patterns, it is clearly revealed that the heat flux generally rises with the slot location moving downstream, and an increase in slot angle from 20° to 40° reduces 50% the heat flux peak at the reattachment point in the slot passage. The results further indicate that the bleed does not raise the heat flux around the slot for all cases except for the area around the downstream slot corner. Among all bleed configurations, the slot angle of 40° located slightly upstream of the incident shock is regarded as the best.

  5. Coupling Through Tortuous Path Narrow Slot Apertures into Complex Cavitivies

    SciTech Connect

    Jedlicka, Russell P.; Castillo, Steven P.; Warne, Larry K.

    1999-07-26

    A hybrid FEM/MoM model has been implemented to compute the coupling of fields into a cavity through narrow slot apertures having depth. The model utilizes the slot model of Warne and Chen [23]-[29] which takes into account the depth of the slot, wall losses, and inhomogeneous dielectrics in the slot region. The cavity interior is modeled with the mixed-order, covariant-projection hexahedral elements of Crowley [32]. Results are given showing the accuracy and generality of the method for modeling geometrically complex slot-cavity combinations.

  6. Computational investigation of slot blowing for fuselage forebody flow control

    NASA Technical Reports Server (NTRS)

    Murman, Scott M.; Rizk, Yehia M.; Schiff, Lewis B.; Cummings, Russell M.

    1992-01-01

    This paper presents a computational investigation of a tangential slot blowing concept for generating lateral control forces on an aircraft fuselage forebody. The effects of varying both the jet width and jet exit velocity for a fixed location slot are analyzed. This work is aimed at aiding researchers in designing future experimental and computational models of tangential slot blowing. The primary influence on the resulting side force of the forebody is seen to be the jet mass flow rate. This influence is sensitive to different combinations of slot widths and jet velocities over the range of variables considered. Both an actuator plane and an overset grid technique are used to model the tangential slot. The overset method successfully resolves the details of the actual slot geometry, extending the generality of the numerical method. The actuator plane concept predicts side forces similar to those produced by resolving the actual slot geometry.

  7. Clean Air Slots Amid Atmospheric Pollution

    NASA Technical Reports Server (NTRS)

    Hobbs, Peter V.

    2002-01-01

    Layering in the Earth's atmosphere is most commonly seen where parts of the atmosphere resist the incursion of air parcels from above and below - for example, when there is an increase in temperature with height over a particular altitude range. Pollutants tend to accumulate underneath the resulting stable layers. which is why visibility often increases markedly above certain altitudes. Here we describe the occurrence of an opposite effect, in which stable layers generate a layer of remarkably clean air (we refer to these layers as clean-air 'slots') sandwiched between layers of polluted air. We have observed clean-air slots in various locations around the world, but they are particularly well defined and prevalent in southern Africa during the dry season August-September). This is because at this time in this region, stable layers are common and pollution from biomass burning is widespread.

  8. Clean Air Slots Amid Atmospheric Pollution

    NASA Technical Reports Server (NTRS)

    Hobbs, Peter V.

    2002-01-01

    Layering in the Earth's atmosphere is most commonly seen where parts of the atmosphere resist the incursion of air parcels from above and below - for example, when there is an increase in temperature with height over a particular altitude range. Pollutants tend to accumulate underneath the resulting stable layers. which is why visibility often increases markedly above certain altitudes. Here we describe the occurrence of an opposite effect, in which stable layers generate a layer of remarkably clean air (we refer to these layers as clean-air 'slots') sandwiched between layers of polluted air. We have observed clean-air slots in various locations around the world, but they are particularly well defined and prevalent in southern Africa during the dry season August-September). This is because at this time in this region, stable layers are common and pollution from biomass burning is widespread.

  9. Orthogonal feeding techniques for tapered slot antennas

    NASA Technical Reports Server (NTRS)

    Lee, Richard Q.; Simons, Rainee N.

    1998-01-01

    For array of "brick" configuration there are electrical and mechanical advantages to feed the antenna with a feed on a substrate perpendicular to the antenna substrate. Different techniques have been proposed for exciting patch antennas using such a feed structure.Rncently, an aperture-coupled dielectric resonator antenna using a perpendicular feed substrate has been demonstrated to have very good power coupling efficiency. For a two-dimensional rectangular array with tapered slot antenna elements, a power combining network on perpendicular substrate is generally required to couple power to or from the array. In this paper, we will describe two aperture-coupled techniques for coupling microwave power from a linearly tapered slot antenna (LTSA) to a microstrip feed on a perpendicular substrate. In addition, we will present measured results for return losses and radiation patterns.

  10. Motivation, masochism, and slot machine gambling.

    PubMed

    Forrest, David V

    2015-03-01

    In the interaction between the rapidly proliferating slot gambling machines and Americans' minds and brains, there are subtle lures that keep people playing, and that even the game devisers do not fully understand. As they project onto the random machines, people enter a zone that resembles a meditative trance I have called praying to the god of chance. Masochism as it applies to gambling is a dynamic concept that requires the suffering to be viewed by imagined and projected parental imagos, who reward the gambler with love if not gambling success. Other motivations are evident in slot machine players, such as grief gambling and a fantasy of controlling losses. While gambling is as universal as religious instincts, state sponsorship of machine gambling is a conflict of interest for government, which is established to promote the general welfare, not addict the citizenry to raise revenues.

  11. Slotted Antenna with Anisotropic Magnetic Loading

    DTIC Science & Technology

    2016-07-26

    10 SLOTTED ANTENNA WITH ANISOTROPIC MAGNETIC LOADING STATEMENT OF GOVERNMENT INTEREST [0001] The invention described herein may be manufactured...therefor. CROSS REFERENCE TO OTHER PATENT APPLICATIONS [0002] None. BACKGROUND OF THE INVENTION (1) Field of the Invention [0003] The present invention ...of the VSWR curve, and modest bandwidth in each passband. SUMMARY OF THE INVENTION [0006] It is a first object of the present invention to provide

  12. The Slotted Blade Axial-Flow Blower

    DTIC Science & Technology

    1955-09-01

    YORK 18, NEW YORK w is|’ .THE SLOTTED BLADE AXIAL-FLOW BLOVER AUG 0 1 13941J F Dr. H. E. Sheets, Member ASME Chief Research and Development Engineer ... blades of an axial flow blower. The subject of boundary-layer control has attracted considerable attention in respect to the isolated airfoil (1)1 but... blades . Flow through airfoils displays a region of laminar flow beginning at the leading edge. Further downstream, at approximately the location of the

  13. Digital time slot display for Omega receiver

    NASA Technical Reports Server (NTRS)

    Smith, R. E.

    1976-01-01

    Methods of decoding a digital word to display alpha-numeric characters for driving a standard seven-segment LED display have been devised for Omega station identification. The circuit could replace the system now being used in Ohio University's Omega receivers, which lights one of eight LED's to signify the Omega time slot being received. The letters A through H, representing the Omega stations, can be read directly from the seven-segment display.

  14. Congestion Pricing for Aircraft Pushback Slot Allocation

    PubMed Central

    Zhang, Yaping

    2017-01-01

    In order to optimize aircraft pushback management during rush hour, aircraft pushback slot allocation based on congestion pricing is explored while considering monetary compensation based on the quality of the surface operations. First, the concept of the “external cost of surface congestion” is proposed, and a quantitative study on the external cost is performed. Then, an aircraft pushback slot allocation model for minimizing the total surface cost is established. An improved discrete differential evolution algorithm is also designed. Finally, a simulation is performed on Xinzheng International Airport using the proposed model. By comparing the pushback slot control strategy based on congestion pricing with other strategies, the advantages of the proposed model and algorithm are highlighted. In addition to reducing delays and optimizing the delay distribution, the model and algorithm are better suited for use for actual aircraft pushback management during rush hour. Further, it is also observed they do not result in significant increases in the surface cost. These results confirm the effectiveness and suitability of the proposed model and algorithm. PMID:28114429

  15. Congestion Pricing for Aircraft Pushback Slot Allocation.

    PubMed

    Liu, Lihua; Zhang, Yaping; Liu, Lan; Xing, Zhiwei

    2017-01-01

    In order to optimize aircraft pushback management during rush hour, aircraft pushback slot allocation based on congestion pricing is explored while considering monetary compensation based on the quality of the surface operations. First, the concept of the "external cost of surface congestion" is proposed, and a quantitative study on the external cost is performed. Then, an aircraft pushback slot allocation model for minimizing the total surface cost is established. An improved discrete differential evolution algorithm is also designed. Finally, a simulation is performed on Xinzheng International Airport using the proposed model. By comparing the pushback slot control strategy based on congestion pricing with other strategies, the advantages of the proposed model and algorithm are highlighted. In addition to reducing delays and optimizing the delay distribution, the model and algorithm are better suited for use for actual aircraft pushback management during rush hour. Further, it is also observed they do not result in significant increases in the surface cost. These results confirm the effectiveness and suitability of the proposed model and algorithm.

  16. Bypass Flow Study

    SciTech Connect

    Richard Schultz

    2011-09-01

    The purpose of the fluid dynamics experiments in the MIR (Matched Index of-Refraction) flow system at Idaho National Laboratory (INL) is to develop benchmark databases for the assessment of Computational Fluid Dynamics (CFD) solutions of the momentum equations, scalar mixing, and turbulence models for the flow ratios between coolant channels and bypass gaps in the interstitial regions of typical prismatic standard fuel element (SFE) or upper reflector block geometries of typical Modular High-temperature Gas-cooled Reactors (MHTGR) in the limiting case of negligible buoyancy and constant fluid properties. The experiments use Particle Image Velocimetry (PIV) to measure the velocity fields that will populate the bypass flow study database.

  17. Efficient finite element simulation of slot spirals, slot radomes and microwave structures

    NASA Technical Reports Server (NTRS)

    Gong, J.; Volakis, J. L.

    1995-01-01

    This progress report contains the following two documents: (1) 'Efficient Finite Element Simulation of Slot Antennas using Prismatic Elements' - A hybrid finite element-boundary integral (FE-BI) simulation technique is discussed to treat narrow slot antennas etched on a planar platform. Specifically, the prismatic elements are used to reduce the redundant sampling rates and ease the mesh generation process. Numerical results for an antenna slot and frequency selective surfaces are presented to demonstrate the validity and capability of the technique; and (2) 'Application and Design Guidelines of the PML Absorber for Finite Element Simulations of Microwave Packages' - The recently introduced perfectly matched layer (PML) uniaxial absorber for frequency domain finite element simulations has several advantages. In this paper we present the application of PML for microwave circuit simulations along with design guidelines to obtain a desired level of absorption. Different feeding techniques are also investigated for improved accuracy.

  18. Gastric Bypass Diet

    MedlinePlus

    ... choose foods that will blend well, such as: Lean ground meats Beans Fish Eggs Soft fruits and ... option after your surgery, as well. Try adding lean cuts of beef, chicken, pork, fish or beans ...

  19. Higher Order Mode Coupling in Feed Waveguide of a Planar Slot Array Antenna

    NASA Technical Reports Server (NTRS)

    Rengarajan, Sembiam

    2011-01-01

    A simple technique was developed to account for the higher order mode coupling between adjacent coupling slots in the feed waveguide of a planar slot array. The method uses an equation relating the slot impedance to the slot voltage and a reaction integral involving the equivalent magnetic current of the slot aperture and the magnetic field coupled from an adjacent slot. In the proposed method, one uses the Elliott s design technique to determine tilt angles and lengths of the coupling slots. The radiating slots are modeled as shunt admittances, and the coupling slots are modeled as series impedances.

  20. Hydrothermal circulation in fault slots with topography

    NASA Astrophysics Data System (ADS)

    Titarenko, Sofya; McCaig, Andrew

    2014-05-01

    There are numerous cases where the circulation of hydrothermal fluid is likely to be confined within a permeable fault slot. Examples are (1) the Lost City Hydrothermal Field (LCHF) at 30 N in the Atlantic, which is likely to be controlled by large E-W faults related to the Atlantis transform fault and mass wasting on the southern wall of the Atlantis Massif, and (2) large normal faults bounding the Hess Deep rift in the East Pacific, which contain intense hydrothermal metamorphic assemblages in lower crustal gabbros formed at 200-350 ° C. This type of circulation could occur anywhere where steep faults cut the oceanic crust, including large near-axis normal faults, transform faults and faults at subduction bend zones, and could be the major way in which the upper mantle and lower crust are hydrated. It is therefore important to constrain the controls on temperature conditions of alteration and hence mineral assemblages. Previous 2-D modelling of the LCHF shows that seafloor topography and permeability structure combine together to localise the field near the highest point of the Atlantis Massif. Our new models are 3-D, based on a 10km cube with seafloor topography of ~ 2km affecting both the fault slot and impermeable wall rocks. We have used Comsol multiphysics in this modelling, with a constant basal heatflow corresponding to the near conductive thermal gradient measured in IODP Hole 1309D, 5km north of the LCHF, and a constant temperature seafloor boundary condition. The wall rocks of the slot have a permeability of 10-17 m2 while permeability in the slot is varied between 10-14 and 10-15 m2. Initial conditions are a conductive thermal structure corresponding to the basal heatflow at steady state. Generic models not based on any particular known topography quickly stabilise a hydrothermal system in the fault slot with a single upflow zone close to the model edge with highest topography. In models with a depth of circulation in the fault slot of about 6 km

  1. Slot-coupled CW standing wave accelerating cavity

    DOEpatents

    Wang, Shaoheng; Rimmer, Robert; Wang, Haipeng

    2017-05-16

    A slot-coupled CW standing wave multi-cell accelerating cavity. To achieve high efficiency graded beta acceleration, each cell in the multi-cell cavity may include different cell lengths. Alternatively, to achieve high efficiency with acceleration for particles with beta equal to 1, each cell in the multi-cell cavity may include the same cell design. Coupling between the cells is achieved with a plurality of axially aligned kidney-shaped slots on the wall between cells. The slot-coupling method makes the design very compact. The shape of the cell, including the slots and the cone, are optimized to maximize the power efficiency and minimize the peak power density on the surface. The slots are non-resonant, thereby enabling shorter slots and less power loss.

  2. Method for selectively controlling flow across slotted liners

    SciTech Connect

    Peavy, M.A.; Dees, J.M.

    1993-08-31

    A process is described for decreasing flow rate across the radial boundary of a selected interval in a well bore containing a slotted liner comprising: placing an explosive and an internally catalyzed resin solution inside an elongated container; locating the elongated container opposite the selected interval in the well bore where flow rate through the slotted liner is to be decreased; firing the explosive; and allowing the resin to cure on the slotted liner before initiating flow through the well. A method is described for decreasing production of unwanted fluids from a horizontal well containing a slotted liner comprising: placing an explosive and an internally catalyzed resin inside an elongated container; placing the elongated container opposite an interval in the horizontal well where unwanted fluid is entering the well bore through the slotted liner; firing the explosive; and permitting the resin to cure on the slotted liner before initiating flow in the well.

  3. 14 CFR 93.218 - Slots for transborder service to and from Canada.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... level of slots of 42 slots at LaGuardia, 36 slots at O'Hare for the Sumner season, and 32 slots at O'Hare in the Winter season. (c) Any modification to the slot base by the Government of Canada or...

  4. Longitudinal slots in dielectric-filled rectangular waveguides

    NASA Astrophysics Data System (ADS)

    Rengarajan, Sembiam R.; Steinbeck, Michael

    1993-09-01

    A rigorous analysis is conducted of a dielectric-filled rectangular waveguide, in whose broad wall a longitudinal radiating slot has been cut; the coupled integral equations for the aperture electric field of a thick wall slot are solved by the method of moments. Attention is given to numerical results for the slot characteristics over a range of dielectric permittivity values. It is noted that the shunt admittance representation is poor for higher dielectric permittivity values.

  5. Coupling characteristics between slot plasmonic mode and dielectric waveguide mode

    NASA Astrophysics Data System (ADS)

    Hu, Shuai; Liu, Fang; Wan, Ruiyuan; Huang, Yidong

    2010-12-01

    A hybrid coupler composed of a slot plasmonic waveguide and a dielectric waveguide is proposed and its coupling characteristics are analyzed. The simulation results show that the ultra-small mode of the slot plasmonic waveguide can be excited efficiently by the dielectric waveguide mode within the coupling length of just several microns, which provides an interface between the slot plasmonic devices and dielectric devices. Meanwhile, based on this hybrid the coupler, a highly integrated refractive index sensor could be realized.

  6. Superior Vena Cava Bypass

    PubMed Central

    Trainini, Jorge Carlos; Auricchio, Renato; Del Bagno, Horacio Augusto; Federico, Vicente; Acrich, Mario Willie; Osorio, Julio Nestor

    1983-01-01

    A case of superior vena cava obstruction due to carcinoma of unknown origin is reported. A superior vena cava bypass with polytetrafluoroethylene was performed by suturing the prosthesis to the left innominate vein and the right atrium, respectively. Long-term satisfactory results were achieved. Images PMID:15227139

  7. SOLPS Modeling of Slot Divertor Configuration on DIII-D

    NASA Astrophysics Data System (ADS)

    Sang, C. F.; Stangeby, P. C.; Guo, H. Y.; Lao, L. L.

    2015-11-01

    A major thrust of the DIII-D boundary/PMI initiative is to develop an advanced divertor configuration for next-step devices, such as FNSF and DEMO. We are adopting an integrated approach by optimizing both divertor structure and magnetic shape. Initial SOLPS modeling was carried out to optimize divertor structure shape to enhance divertor power dissipation, focusing on slot configurations. In particular, four different slot divertor structures, i.e., orthogonal-target slot, slanted-target slot, very narrow slot and v-shaped slot have been analyzed and comparisons made with an open divertor structure. It is found that the slot helps to trap recycling neutrals and impurities thus increasing radiative power dissipation in the divertor, reducing the electron temperature Te and the perpendicular heat flux q⊥ at the target plate. As expected, a narrower slot leads to lower Te and q⊥ than a less narrow one. The v-shaped slot appears to be especially effective at redirecting and concentrating recycling neutrals and impurities near the separatrix, thus promoting detachment at a lower upstream density than the other configurations. Work supported by US DOE under DE-FC02-04ER54698.

  8. An experimental study of slot injection into a supersonic stream

    NASA Technical Reports Server (NTRS)

    Kenworthy, M.; Schetz, J. A.

    1973-01-01

    An experimental investigation of two-dimensional tangential-slot injection into a turbulent boundary layer at a freestream Mach number of 2.4 has been conducted. Nearly adiabatic surface temperatures were maintained during all tests. Static and pitot pressure profiles at four stations downstream of the slot were obtained. Skin friction was measured at the last three stations with a self-nulling balance. Schlieren photographs of the flow field were also obtained. Most of the data were obtained with slot Mach numbers of 0.31 and 0.66 corresponding to slot pressure less than and equal to stream static pressure, respectively. For the latter matched-pressure case, tangential slot injection reduced the surface shear at the three measuring stations by about 60 to 20 percent for increasing downstream distances from the slot of 12 to 28 slot heights. However, for the other case where slot pressure was less than stream static pressure, the effect of injection was to increase the shear by about 90 percent at the last downstream station of 28 slot heights. This increase in shear is attributed to the rapid acceleration of the low speed injectant stream by the high speed main stream and the increasing pressure through the recompression zone which is absent for the matched pressure case.

  9. Slot-coupled patch antenna with coplanar waveguide feed

    NASA Technical Reports Server (NTRS)

    Lee, Richard Q.; Simons, Rainee N.

    1993-01-01

    Two slot-coupled feeding techniques for exciting a patch antenna with a coplanar waveguide (CPW) were experimentally investigated. In the first technique, a CPW with two notches on both sides of the slot lines is used to couple power to the antenna through a narrow rectangular slot. In the second technique, a grounded CPW with a series gap in the center strip conductor is used to couple power to the antenna through a 'dumbbell' slot. Results indicated that both techniques are feasible and yield high coupling efficiency.

  10. On the Mutual Coupling between Circular Resonant Slots

    NASA Technical Reports Server (NTRS)

    Abou-Khousa, M. A.; Kharkovshy, S.; Zoughi, R.

    2007-01-01

    For near- and far-field microwave imaging purposes, array of circular resonant slots can be utilized to sample the electric field at a given reference plane. In general, the sensitivity of such an array is impaired by the existing mutual coupling between the radiating elements or in this case circular slots. The mutual coupling problem imposes a design tradeoff between the resolution of the array and the overall system sensitivity and dynamic range. In this paper, the mutual coupling between circular resonant slots in conducting ground plane is investigated both numerically and experimentally. In particular, the mutual coupling in the E- and H-plane configurations of two identical slots is studied.

  11. Republic F-84 Thunderjet with Slotted Nozzle

    NASA Image and Video Library

    1958-05-21

    A Republic F-84 Thunderjet dramatically modified at the NASA Lewis Research Center to investigate the use of slotted nozzles to reduce exhaust noise. The F-84 was a single-seat fighter-bomber powered by an Allison J35 turbojet. It was the Air Force’s first post-World War II tactical aircraft and was used extensively in the Korean War. The laboratory had acquired the aircraft in 1954 and modified it in order to demonstrate the reverse thruster. The tail end of the aircraft was then removed for a series of large nozzle investigations. Lewis researchers launched an extensive program in the mid-1950s to develop methods of reducing engine noise as the airline industry was preparing to introduce the first turbojet-powered passenger aircraft. The early NACA investigations determined that the primary source of noise was the mixing of the engine’s hot exhaust with the cool surrounding air. Lewis researchers studied many different nozzles designed to facilitate this mixing. Nozzles with elongated exit sections, as seen in this photograph, produced lower noise levels. These long slot nozzles were also considered for Short Take-off and Landing aircraft because their long flat surfaces provided lift. In 1958 Lewis tested several full-scale slot nozzles on the F-84. The researchers, led by Willard Cole, sought to determine the noise-generation characteristics for nozzles having large a width-to-height ratio. The nozzle in this photograph has a 100 to 1 width-to-height ratio. Cole determined that the experimental nozzles produced the same levels of sound as the standard nozzle, but the changes in the directional noise were substantial.

  12. Circular Waveguide Slotted Antenna with Inclined Beam

    NASA Astrophysics Data System (ADS)

    Sekretarov, S. S.; Vavriv, D. M.

    2009-03-01

    The novel design of a Ku-band circular waveguide slotted antenna is proposed. In contrast to standard antennas of this type, the main beam of the developed antenna is inclined from its surface normal by the value noticeably exceeding the beam width, which is necessary e.g. to reduce the radar cross section of the antenna in the direction towards an illuminated target. The design features of such antennas are considered. The practical desing of the antenna developed is presented along with the comparison of the simulation and experimental results.

  13. Multilayer Microstrip Slot And Dipole Array Antenna

    NASA Technical Reports Server (NTRS)

    Tulintseff, Ann N.

    1994-01-01

    Multilayer antenna structure contains interleaved linear subarrays of microstrip dipole and slot radiating antenna elements to provide compact, dual-band antenna. Structure also contains associated microstrip transmission lines, plus high-power amplifiers for transmission and low-noise amplifiers for reception. Overall function is to transmit in horizontal polarization at frequency of 29.634 GHz and receive in vertical polarization at 19.914 GHz, in direction 44 degrees from broadside to antenna. Antenna structure is part of apparatus described in "Steerable K/Ka-band Antenna for Land-Mobile Satellite Applications," NPO-18772.

  14. Displacement sensor based on plasmonic slot metamaterials

    NASA Astrophysics Data System (ADS)

    Wu, Wei; Ren, Mengxin; Pi, Biao; Cai, Wei; Xu, Jingjun

    2016-02-01

    In this paper, we demonstrate a plasmonic type displacement sensor based on slot metamaterials. The sensors are formed by arranging metamaterial arrays with different dimension parameters adjacently. Hence, the measured spectra would be modified as a result of moving the sensors across the detecting area of the spectrometer. From the spectral changes, the displacement amount could be retrieved. The sensor is demonstrated to be capable of recognizing a displacement of 200 nm, which is equal to the period of the metamaterial lattice, and the sensitivity is largely dependent on the shape and size of the acquisition area of the spectrometer used for spectra analysis.

  15. Results of recent experiments with slotted wings

    NASA Technical Reports Server (NTRS)

    Lachmann, G

    1925-01-01

    This report gives the results of a recent series of experiments performed on a wing designed for a cantilever monoplane. Both wings were trapezial in their ground plan, with their tips rounded elliptically. These wing sections combine all known devices for increasing the lift, namely, the slot, the increased camber and angle of attack by means of an aileron running the whole length of the span. The last advance included in the wing section was an increase in wing area by means of an auxiliary wing adjusted by a sort of rectangular joint.

  16. A new elastic slot system and V-wire mechanics.

    PubMed

    Wichelhaus, Andrea

    2017-09-01

    To biomechanically test a new elastic slot system and V-wire mechanics. Conventional twin and self-ligating brackets and the new elastodynamic bracket were biomechanically tested. The conventional brackets had a rectangular 0.022'' slot and the new elastodynamic bracket had a V-slot, a new slot geometry. Torque measurements were performed with 0.018'' × 0.025'' and 0.019'' × 0.025'' stainless steel (ss) archwires. A nickel-titanium V wire was used for the biomechanical measurements on the elastodynamic bracket. The measurements were done with the aid of a six-component measuring sensor. The results of the biomechanical testing revealed play in the brackets with rectangular slot geometry. The V slot in the elastodynamic bracket assured that the wire fit perfectly in the slot. Dynamic moments of 5 to 10 Nmm were transmitted without any play. No permanent deformation of the slot occurred in the new elastodynamic bracket because of the elastic slot. Control of torque for three-dimensional positioning of the teeth in the dental arch with rectangular slot geometry as used in straight-wire therapy is difficult. If torque is bent into the wire, because of the play there is a high risk that either too much, too little, or no moment is transmitted to the teeth. The V-slot archwire/bracket geometry in conjunction with nickel titanium composition has no play and allows a reduction of forces and moments with direct and continuous transmission of torque in the bracket. Because of the elasticity of the bracket, there is an upper limit to the moment possible.

  17. Rectangular Microstrip Antenna with Slot Embedded Geometry

    NASA Astrophysics Data System (ADS)

    Ambresh, P. A.; Hadalgi, P. M.; Hunagund, P. V.; Sujata, A. A.

    2014-09-01

    In this paper, a novel design that improves the performance of conventional rectangular microstrip antenna is discussed. Design adopts basic techniques such as probe feeding technique with rectangular inverted patch structure as superstrate, air filled dielectric medium as substrate and slot embedded patch. Prototype of the proposed antenna has been fabricated and various antenna performance parameters such as impedance bandwidth, return loss, radiation pattern and antenna gain are considered for Electromagnetic-study. The antennas are designed for the wireless application operating in the frequency range of 3.3 GHz to 3.6 GHz, and UK based fixed satellite service application (3 GHz to 4 GHz), and are named as single inverted patch conventional rectangular microstrip antenna (SIP-CRMSA) and slots embedded inverted patch rectangular microstrip antenna (SEIP-RMSA), respectively. Measurement outcomes for SEIP-RMSA1 and SEIP-RMSA2 showed the satisfactory performance with an achievable impedance bandwidth of 260 MHz (7 %) and 250 MHz (6.72 %), with return loss (RL) of -11.06 dB and -17.98 dB, achieved gain of 8.17 dB and 5.17 dB with 10% and 8% size reduction in comparison with the conventional patch antenna.

  18. Vertical Slot Convection: A linear study

    SciTech Connect

    McAllister, A.; Steinolfson, R.; Tajima, T.

    1992-11-01

    The linear stability properties of fluid convection in a vertical slot were studied. We use a Fourier-Chebychev decomposition was used to set up the linear eigenvalue problems for the Vertical Slot Convection and Benard problems. The eigenvalues, neutral stability curves, and critical point values of the Grashof number, G, and the wavenumber were determined. Plots of the real and imaginary parts of the eigenvalues as functions of G and {alpha} are given for a wide range of the Prandtl number, Pr, and special note is made of the complex mode that becomes linearly unstable above Pr {approximately} 12.5. A discussion comparing different special cases facilitates the physical understanding of the VSC equations, especially the interaction of the shear-flow and buoyancy induced physics. Making use of the real and imaginary eigenvalues and the phase properties of the eigenmodes, the eigenmodes were characterized. One finds that the mode structure becomes progressively simpler with increasing Pr, with the greatest complexity in the mid ranges where the terms in the heat equation are of roughly the same size.

  19. Vertical Slot Convection: A linear study

    SciTech Connect

    McAllister, A. ); Steinolfson, R. ); Tajima, T. . Inst. for Fusion Studies)

    1992-11-01

    The linear stability properties of fluid convection in a vertical slot were studied. We use a Fourier-Chebychev decomposition was used to set up the linear eigenvalue problems for the Vertical Slot Convection and Benard problems. The eigenvalues, neutral stability curves, and critical point values of the Grashof number, G, and the wavenumber were determined. Plots of the real and imaginary parts of the eigenvalues as functions of G and [alpha] are given for a wide range of the Prandtl number, Pr, and special note is made of the complex mode that becomes linearly unstable above Pr [approximately] 12.5. A discussion comparing different special cases facilitates the physical understanding of the VSC equations, especially the interaction of the shear-flow and buoyancy induced physics. Making use of the real and imaginary eigenvalues and the phase properties of the eigenmodes, the eigenmodes were characterized. One finds that the mode structure becomes progressively simpler with increasing Pr, with the greatest complexity in the mid ranges where the terms in the heat equation are of roughly the same size.

  20. Comparative Analysis of Bracket Slot Dimensions Evaluating Different Manufacturing Techniques

    DTIC Science & Technology

    2015-04-24

    Dimensions Evaluating Different Manufacturing Techniques JS. A. DeMeo APPROVED: fk_ 4 ’__/ . .S, M.S., Supervising Professor ,....-------__ ’ - ~l!i...manuscript entitled : "Comparative Analysis of Bracket Slot Dimensions Evaluating Different Manufactur ing Techniques" is appropriately acknowledged and...Harm s Way TITLE Comparative Analysis of Bracket Slot Dimensions Evaluating Different Manufacturing Techniques A THESIS Presented to the

  1. 14 CFR 93.227 - Slot use and loss.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... commuter operator or other person holding a slot at a high density airport shall, within 14 days after the... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Slot use and loss. 93.227 Section 93.227... AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Allocation of Commuter and Air Carrier...

  2. 14 CFR 93.227 - Slot use and loss.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Operations at High Density Traffic Airports § 93.227 Slot use and loss. (a) Except as provided in paragraphs... commuter operator or other person holding a slot at a high density airport shall, within 14 days after the... High Density Traffic Airport on Thanksgiving Day, the Friday following Thanksgiving Day, and the...

  3. 14 CFR 93.227 - Slot use and loss.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Operations at High Density Traffic Airports § 93.227 Slot use and loss. (a) Except as provided in paragraphs... commuter operator or other person holding a slot at a high density airport shall, within 14 days after the... High Density Traffic Airport on Thanksgiving Day, the Friday following Thanksgiving Day, and the...

  4. 14 CFR 93.227 - Slot use and loss.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Operations at High Density Traffic Airports § 93.227 Slot use and loss. (a) Except as provided in paragraphs... commuter operator or other person holding a slot at a high density airport shall, within 14 days after the... High Density Traffic Airport on Thanksgiving Day, the Friday following Thanksgiving Day, and the...

  5. 14 CFR 93.227 - Slot use and loss.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Operations at High Density Traffic Airports § 93.227 Slot use and loss. (a) Except as provided in paragraphs... commuter operator or other person holding a slot at a high density airport shall, within 14 days after the... High Density Traffic Airport on Thanksgiving Day, the Friday following Thanksgiving Day, and the...

  6. FDTD Analysis of U-Slot Rectangular Patch Antenna

    NASA Technical Reports Server (NTRS)

    Luk, K. M.; Tong, K. F.; Shum, S. M.; Lee, K. F.; Lee, R. Q.

    1997-01-01

    The U-slot rectangular patch antenna (Figure I) has been found experimentally to provide impedance and gain bandwidths of about 300 without the need of stacked or coplanar parasitic elements [1,2]. In this paper, simulation results of the U-slot patch using FDTD analysis are presented. Comparison with measured results are given.

  7. 49 CFR 236.809 - Signal, slotted mechanical.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Signal, slotted mechanical. 236.809 Section 236.809 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... § 236.809 Signal, slotted mechanical. A mechanically operated signal with an electromagnetic device...

  8. Relaxed Time Slot Negotiation for Grid Resource Allocation

    NASA Astrophysics Data System (ADS)

    Son, Seokho; Sim, Kwang Mong

    Since participants in a computational grid may be independent bodies, some mechanisms are necessary for resolving the differences in their preferences for price and desirable time slots for utilizing/leasing computing resources. Whereas there are mechanisms for supporting price negotiation for grid resource allocation, there is little or no negotiation support for allocating mutually acceptable time slots for grid participants. The contribution of this work is designing a negotiation mechanism for facilitating time slot negotiations between grid participants. In particular, this work adopts a relaxed time slot negotiation protocol designed to enhance the success rate and resource utilization level by allowing some flexibility for making slight adjustments following a tentative agreement for a mutually acceptable time slot. The ideas of the relaxed time slot negotiation are implemented in an agent-based grid testbed, and empirical results of the relaxed time slot negotiation mechanism carried out, (i) a consumer and a provider agent have a mutually satisfying agreement on time slot and price, (ii) consumer agents achieved higher success rates in negotiation, and (iii) provider agents achieved higher utility and resource utilization of overall grid.

  9. 49 CFR 236.809 - Signal, slotted mechanical.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Signal, slotted mechanical. 236.809 Section 236..., INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.809 Signal, slotted mechanical. A mechanically operated signal with an electromagnetic device...

  10. 49 CFR 236.809 - Signal, slotted mechanical.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Signal, slotted mechanical. 236.809 Section 236..., INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.809 Signal, slotted mechanical. A mechanically operated signal with an electromagnetic device...

  11. 49 CFR 236.809 - Signal, slotted mechanical.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Signal, slotted mechanical. 236.809 Section 236..., INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.809 Signal, slotted mechanical. A mechanically operated signal with an electromagnetic device...

  12. 49 CFR 236.809 - Signal, slotted mechanical.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Signal, slotted mechanical. 236.809 Section 236..., INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.809 Signal, slotted mechanical. A mechanically operated signal with an electromagnetic device...

  13. High-responsivity graphene-on-silicon slot waveguide photodetectors

    NASA Astrophysics Data System (ADS)

    Wang, Jiaqi; Cheng, Zhenzhou; Chen, Zefeng; Wan, Xi; Zhu, Bingqing; Tsang, Hon Ki; Shu, Chester; Xu, Jianbin

    2016-07-01

    We demonstrated strong optical absorption in a graphene integrated silicon slot waveguide. Due to the increase in light intensity and decrease of optical mode confinement in the silicon slot, the graphene experienced an increased interaction to the in-plane light. A waveguide absorption of 0.935 dB μm-1 was measured at 1.55 μm wavelengths. Based on the graphene-on-silicon slot waveguide, a compact and high-responsivity photodetector was demonstrated. Benefited from the lack of efficient electron cooling in the suspended graphene and the intensity enhancement effect in the nano slot, a maximum responsivity of 0.273 A W-1 was achieved in the telecommunication band.We demonstrated strong optical absorption in a graphene integrated silicon slot waveguide. Due to the increase in light intensity and decrease of optical mode confinement in the silicon slot, the graphene experienced an increased interaction to the in-plane light. A waveguide absorption of 0.935 dB μm-1 was measured at 1.55 μm wavelengths. Based on the graphene-on-silicon slot waveguide, a compact and high-responsivity photodetector was demonstrated. Benefited from the lack of efficient electron cooling in the suspended graphene and the intensity enhancement effect in the nano slot, a maximum responsivity of 0.273 A W-1 was achieved in the telecommunication band. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr03122f

  14. FDTD Analysis of U-Slot Rectangular Patch Antenna

    NASA Technical Reports Server (NTRS)

    Luk, K. M.; Tong, K. F.; Shum, S. M.; Lee, K. F.; Lee, R. Q.

    1997-01-01

    The U-slot rectangular patch antenna (Figure I) has been found experimentally to provide impedance and gain bandwidths of about 300 without the need of stacked or coplanar parasitic elements [1,2]. In this paper, simulation results of the U-slot patch using FDTD analysis are presented. Comparison with measured results are given.

  15. Acoustic behavior of tuning slots of labial organ pipes.

    PubMed

    Rucz, Péter; Augusztinovicz, Fülöp; Angster, Judit; Preukschat, Tim; Miklós, András

    2014-05-01

    The effect of tuning slots on the sound characteristics of labial organ pipes is investigated in this paper by means of laboratory experiments. Besides changing the pitch of the pipe, the tuning slot also plays an important role in forming the timbre. The objectives of this contribution are to document the influence of tuning slots built with different geometries on the pipe sound and to validate the observed tendencies by means of reproducible experiments. It is found that the measured steady state sound spectra show unique characteristics, typical only for tuning slot organ pipes. By separately adjusting the geometrical parameters of the tuning slots on experimental pipes, the impact of each scaling parameter on the steady state spectrum is determined. It is shown that the scaling procedures used currently in organ building practice do not provide sufficient control over the sound characteristics, leaving the capabilities provided by the tuning slot unexploited. Subjective comparison made by organ builders of sound recordings of various setups confirms that the observed sound quality of tuning slot pipes is strongly dependent on the scaling of the slot.

  16. Manipulating Slot Machine Preference in Problem Gamblers through Contextual Control

    ERIC Educational Resources Information Center

    Nastally, Becky L.; Dixon, Mark R.; Jackson, James W.

    2010-01-01

    Pathological and nonpathological gamblers completed a task that assessed preference among 2 concurrently available slot machines. Subsequent assessments of choice were conducted after various attempts to transfer contextual functions associated with irrelevant characteristics of the slot machines. Results indicated that the nonproblem gambling…

  17. The Role of Ring Current on Slot Region Penetration

    NASA Technical Reports Server (NTRS)

    Fok, Mei-Ching; Elkington, Scot

    2006-01-01

    During magnetic quiet times, the inner belt, slot region and the outer belt are well defined regions. However, during some major storms, outer belt particles penetrate inward and significantly fill the slot region. In some extreme events, the outer belt particles travel through the slot and create a new belt in the inner region that persists from months to years. In this paper, we examine the role of the ring current on this radiation belt penetration into the slot region. The storm-time intensification of the ring current produces strong magnetic depression in the inner magnetosphere. This perturbation and its fluctuation enhance the radial transport and diffusion of the outer radiation belt particles. We perform kinetic and test-particle calculations to quantitatively assess the effects of the ring current field on filling of the slot region. Simulation results during major storms will be presented and discussed.

  18. Practical Tests with the "auto Control Slot." Part I : Lecture

    NASA Technical Reports Server (NTRS)

    Lachmann, G

    1930-01-01

    For some time the D.V.L. has been investigating the question of applicability of Handley Page slotted wings to German airplanes. Comparitive gliding tests were made with open and closed slots on an Albatros L 75 airplane equipped with the Handley Page "auto control slots." This investigation served to determine the effect of the auto control slot on the properties and performances of airplanes at large angles of attack. The most important problems were whether the angle of glide at small angles of attack can be increased by the adoption of the auto control slot and, in particular, as to whether the flight characteristics at large angles of attack are improved thereby and equilibrium in gliding flight is guaranteed even at larger than ordinary angles of attack.

  19. Wind tunnel study of slot spoilers for direct lift control

    NASA Technical Reports Server (NTRS)

    Andrisani, D., II; Gentry, G. L., Jr.; Stickle, J. W.

    1972-01-01

    An investigation was conducted in a 300-mph 7- by 10- foot tunnel to obtain data for a slot spoiler direct lift control system. Slot spoilers are believed to have advantages over flap-type direct lift control (DLC) systems because of the small amount of power required for actuation. These tests, run at a Reynolds number of 1,400,000 showed that up to 78 percent of the lift due to flap deflection could be spoiled by opening several spanwise slots within the flaps. For a given lift change the drag change was significantly less than that which would be obtained by a variable flap DLC system. A nozzle-shaped slot was the most effective of the slot shapes tested.

  20. The Role of Ring Current on Slot Region Penetration

    NASA Technical Reports Server (NTRS)

    Fok, Mei-Ching; Elkington, Scot

    2006-01-01

    During magnetic quiet times, the inner belt, slot region and the outer belt are well defined regions. However, during some major storms, outer belt particles penetrate inward and significantly fill the slot region. In some extreme events, the outer belt particles travel through the slot and create a new belt in the inner region that persists from months to years. In this paper, we examine the role of the ring current on this radiation belt penetration into the slot region. The storm-time intensification of the ring current produces strong magnetic depression in the inner magnetosphere. This perturbation and its fluctuation enhance the radial transport and diffusion of the outer radiation belt particles. We perform kinetic and test-particle calculations to quantitatively assess the effects of the ring current field on filling of the slot region. Simulation results during major storms will be presented and discussed.

  1. Practical Tests with the "auto Control Slot." Part II : Discussion

    NASA Technical Reports Server (NTRS)

    Lachmann, G

    1930-01-01

    For some time the D.V.L. has been investigating the question of applicability of Handley Page slotted wings to German airplanes. Comparitive gliding tests were made with open and closed slots on an Albatros L 75 airplane equipped with the Handley Page "auto control slots." This investigation served to determine the effect of the auto control slot on the properties and performances of airplanes at large angles of attack. The most important problems were whether the angle of glide at small angles of attack can be increased by the adoption of the auto control slot and, in particular, as to whether the flight characteristics at large angles of attack are improved thereby and equilibrium in gliding flight is guaranteed even at larger than ordinary angles of attack.

  2. Access to the bypassed stomach after gastric bypass.

    PubMed

    Fobi, M A; Chicola, K; Lee, H

    1998-06-01

    The gastric bypass (GBP) Operation is progressively being widely used to treat severe obesity. One problem with this operation is that it leaves the bypassed segment of the gastrointestinal tract not readily available for either mechanical, radiological or endoscopic evaluation. We have addressed this problem by putting a gastrostomy tube in the bypassed stomach at the time of the GBP. A radio-opaque marker placed around the gastrostomy site enables easy radiological localization of and thus easy percutaneous access to the bypassed stomach. The surgical technique is presented.

  3. Seal Bypass Systems (Invited)

    NASA Astrophysics Data System (ADS)

    Cartwright, J. A.

    2009-12-01

    Joe Cartwright 3DLab, School of Earth, Ocean and Planetary Sciences, Cardiff University, Main Building, Park Place, Cardiff CF10 3YE, Wales, UK (cartwrightja@cf.ac.uk) A conceptual model for the analysis of the sealing potential of caprock sequences is summarised here based on the recognition that many high quality seals are breached episodically or semi-permanently by a range of geological structures that act as seal by-pass systems (SBS). We formally define SBS as seismically resolvable geological features embedded within sealing sequences that promote cross-stratal fluid migration and allow fluids to bypass the pore network. We advance the concept that if such bypass systems exist within a given sealing sequence sequence, then predictions of sealing capacity based exclusively on rock physical properties such as capillary entry pressure/hydraulic conductivity will be largely negated by the capacity of the bypass system to breach the grain and pore network. This model is based largely on observations of sealing sequences using 3D seismic data, in which there is direct evidence of highly focused vertical or sub-vertical fluid flow from subsurface reservoirs up through the sealing sequence with leakage internally at higher levels or to the surface as seeps or pockmarks. We classify SBS into three main classes based on seismic interpretational criteria: (1) fault related, (2) intrusion-related, and (3) pipe-related. Examples are presented of each class of SBS in a relevant context of a particular sealing sequence, and where seismic evidence of hydrocarbon leakage allows the role of the bypass features to be evaluated. These include mud volcano conduits, sandstone intrusions, normal and thrust faults, blowout pipes and igneous intrusions. We show how each class exhibits different modes of behaviour with potential for different scaling relationships between flux and dimensions, and different short and long-term impacts on seal behaviour. We conclude with an analysis of

  4. Student-Led Objective Tutorial (SLOT) in Medical Education.

    PubMed

    Sivagnanam, Gurusamy; Saraswathi, Simansalam; Rajasekaran, Aiyalu

    2006-12-01

    Purpose - To assess an innovative tutoring program named 'Student-Led Objective Tutorial' (SLOT) among undergraduate medical students. Method - The program was conceptualized by the Pharmacology Unit of Faculty of Medicine and Health Sciences, Asian Institute of Medicine Science & Technology (AIMST), Malaysia and implemented in the middle of 2005. A cohort of 246 medical undergraduate students (spread across 5 consecutive batches) participated. Following a brief explanation on the purpose and nature of SLOT, each batch was divided into small groups and was given a reading assignment on 4 previously delivered lecture topics. Each group was asked to prepare 3-5 multiple choice questions (MCQs) of their own in PowerPoint format to be presented, in turns, to the whole class on the day of SLOT. The proceedings were facilitated by 2 lecturers. Student feedback on the efficacy and benefits were assessed through an anonymous self administered questionnaire. Results - About 76% (188) of the students favored SLOT. The acceptance rate of SLOT was higher among males. There was no significant difference between batches in their opinions on whether to pursue SLOT in future. The most prevalent positive comment was that SLOT enhanced learning skills, and the negative comment being, it consumed more time. Conclusions - SLOT is a novel tutorial method which can offset faculty shortage with advantages like enhanced interest among teachers and learners, uniform reach of content, opportunities for group learning, and involvement of visual aids as teaching-learning (T-L) method. SLOT unraveled the students' potential of peer tutoring both inside as well as outside the classroom. Consumer tutors (students) can be tapped as a resource for SLOT for all subjects and courses in healthcare teaching.

  5. Slot-line applicator for microwave hyperthermia.

    PubMed

    Togni, Paolo; Drízd'al, Tomás; Vrba, Jan; Vannucci, Luca

    2009-01-01

    Electromagnetic field interaction with biological tissues and their applications in cancer treatment research has become of growing interest. This paper describes the possibility of using a slot-line type applicator for microwave hyperthermia treatment in oncology. What we aim to show in this paper is that this type of applicator is particularly suitable for the treatment of superficial cancers with depths 2-3 cm below the body surface. To support this thesis, a 3D electromagnetic field simulator has been used to predict the specific absorbed ratio (SAR), and the consequent temperature distribution in the area under treatment. The results of the simulations are supported by experimental temperature measurements made with the help of an infrared thermo-camera on a homogeneous agar phantom. The possibility to use an array configuration of this applicator in order to treat bigger areas is also analyzed using computer simulation of SAR distribution.

  6. Bypass surgery for lower extremity limb salvage: vein bypass.

    PubMed

    El-Sayed, Hosam F

    2012-01-01

    Bypass surgery for limb salvage in cases of chronic limb ischemia is a well-established treatment modality. Use of an autogenous vein provides the best conduit for infrainguinal arterial bypass procedures, particularly for bypass to the infrapopliteal arteries. In this article, we discuss infrainguinal vein bypass surgery including indications, perioperative care, and long-term follow up. We also discuss the outcomes of the procedure with regard to patient survival and limb salvage. The autogenous vein continues to be the best available conduit with the highest patency rate and the best treatment option. Compared to all other revascularization options for infrainguinal disease, the vein bypass has the best limb salvage and long-term survival in patients appropriately selected for the procedure.

  7. Superstrate effects on slot-coupled microstrip antennas

    NASA Astrophysics Data System (ADS)

    Huang, Chang-Hsiu; Hsu, Powen

    1991-09-01

    An analysis for studying the superstrate (cover) effects on the slot-coupled microstrip antennas is presented. The approach is based on the reciprocity theorem and uses the grounded double- and single-layer dielectric slab Green's functions in a moment method solution for the unknown slot fields and patch currents. From these fields and currents, various characteristics of the antenna can be extracted, such as the radiation efficiency, directivity, input impedance, and resonant frequency. Numerical calculations showing superstrate effects on these antenna characteristics are presented. The input matches obtained from proper adjustment of the slot and patch dimensions are discussed.

  8. Mass flux similarity for slotted transonic-wind-tunnel walls

    NASA Technical Reports Server (NTRS)

    Everhart, Joel L.; Goradia, Suresh H.

    1991-01-01

    A discussion of the flow field measurements obtained in the vertical plane at several stations along the centerline of slots in two different longitudinally slotted wind tunnel walls is presented. The longitudinal and transverse components of the data are then transformed using the concept of flow similarity to demonstrate the applicability of the technique to the development of the viscous shear flow along and through a slotted wall of an airfoil tunnel. Results are presented showing the performance of the similarity transformations with variations in tunnel station, Mach number, and airfoil induced curvature of the tunnel free stream.

  9. On the Mutual Coupling Between Circular Resonant Slots

    NASA Technical Reports Server (NTRS)

    Abou-Khousa, M. A.; Kharkovsky, S.; Zoughi, R.

    2007-01-01

    For near- and far-field microwave imaging purposes, array of circular resonant slots can be utilized to sample the electric field at a given reference plane. In general, the sensitivity of such array probes is impaired by the mutual coupling present between the radiating elements. The mutual coupling problem poses a design tradeoff between the resolution of the array and its sensitivity. In this paper, we investigate the mutual coupling between circular resonant slots in conducting ground plane both numerically and experimentally. Based on the analysis of the dominant coupling mechanism, i.e., the surface currents, various remedies to reduce the slots' mutual coupling are proposed and verified.

  10. Passage of downstream migrant American eels through an airlift-assisted deep bypass

    USGS Publications Warehouse

    Haro, Alexander J.; Watten, Barnaby J.; Noreika, John

    2016-01-01

    Traditional downstream guidance and bypass facilities for anadromous fishes (i.e., surface bypasses, surface guidance structures, and behavioral barriers) have frequently been ineffective for anguillid eels. Because eels typically spend the majority of their time near the bottom in the vicinity of intake structures, deep bypass structures with entrances near the bottom hold promise for increased effectiveness, thereby aiding in the recovery of this important species. A new design of a deep bypass system that uses airlift technology (the Conte Airlift Bypass) to induce flow in a bypass pipe was tested in a simulated intake entrance environment under controlled laboratory conditions. Water velocities of 0.9–1.5 m s−1 could be generated at the bypass entrance (opening with 0.073 m2 area), with corresponding flows through the bypass pipe of 0.07–0.11 m3 s−1. Gas saturation and hydrostatic pressure within the bypass pipe did not vary appreciably from a control (no air) condition under tested airflows. Migratory silver-phase American eels (Anguilla rostrata) tested during dark conditions readily located, entered, and passed through the bypass; initial avoidance rates (eels approaching but not entering the bypass entrance) were lower at higher entrance velocities. Eels that investigated the bypass pipe entrance tended to enter headfirst, but those that then exited the pipe upstream did so more frequently at lower entrance velocities. Eels appeared to swim against the flow while being transported downstream through the pipe; median transit times through the bypass for each test velocity ranged from 5.8 to 12.2 s, with transit time decreasing with increasing entrance velocity. Eels did not show strong avoidance of the vertical section of the pipe which contained injected air. No mortality or injury of bypassed eels was observed, and individual eels repeatedly passed through the bypass at rates of up to 40 passes per hour, suggesting that individuals do not

  11. Ascent ability of brown trout, Salmo trutta, and two Iberian cyprinids − Iberian barbel, Luciobarbus bocagei, and northern straight-mouth nase, Pseudochondrostoma duriense − in a vertical slot fishway

    USGS Publications Warehouse

    Sanz-Ronda, Fco. Javier; Bravo-Cordoba, F.J.; Fuentes-Perez, J.F.; Castro-Santos, Theodore R.

    2016-01-01

    Passage performance of brown trout (Salmo trutta), Iberian barbel (Luciobarbus bocagei), and northern straight-mouth nase (Pseudochondrostoma duriense) was investigated in a vertical slot fishway in the Porma River (Duero River basin, Spain) using PIT telemetry. We analysed the effects of different fishway discharges on motivation and passage success. Both cyprinid species ascended the fishway easily, performing better than the trout despite their theoretically weaker swimming performance. Fishway discharge affected fish motivation although it did not clearly influence passage success. Observed results can guide design and operation criteria of vertical slot fishways for native Iberian fish.

  12. Heart bypass surgery incision (image)

    MedlinePlus

    ... the left part of the chest between the ribs. This incision is much less traumatic than the traditional heart bypass surgery incision which separates the breast bone. Minimally invasive heart bypass surgery allows the patient less pain and a faster recovery.

  13. Spiritual Bypass: A Preliminary Investigation

    ERIC Educational Resources Information Center

    Cashwell, Craig S.; Glosoff, Harriet L.; Hammond, Cheree

    2010-01-01

    The phenomenon of spiritual bypass has received limited attention in the transpersonal psychology and counseling literature and has not been subjected to empirical inquiry. This study examines the phenomenon of spiritual bypass by considering how spirituality, mindfulness, alexithymia (emotional restrictiveness), and narcissism work together to…

  14. Spiritual Bypass: A Preliminary Investigation

    ERIC Educational Resources Information Center

    Cashwell, Craig S.; Glosoff, Harriet L.; Hammond, Cheree

    2010-01-01

    The phenomenon of spiritual bypass has received limited attention in the transpersonal psychology and counseling literature and has not been subjected to empirical inquiry. This study examines the phenomenon of spiritual bypass by considering how spirituality, mindfulness, alexithymia (emotional restrictiveness), and narcissism work together to…

  15. Medium bypass turbofan engine

    SciTech Connect

    Williams, S.B.; Jones, J.F.; Dorer, D.K.

    1986-07-08

    A gas turbine engine of the turbofan type is described which consists of: A. a generally tubular axially extending housing assembly defining a radially outer annular bypass duct extending from the inlet end of the housing assembly to the exhaust end thereof; B. an annular burner positioned within the housing assembly radially inwardly of the bypass duct and concentric to the central axis of the housing assembly; C. a low pressure spool assembly including a first shaft journaled on the central axis of the housing assembly, a fan on the first shaft disposed proximate the inlet end of the housing assembly, and a low pressure turbine on the first shaft disposed proximate the exhaust end of the housing assembly; and D. a high pressure spool assembly including a hollow second shaft telescopically received over the first shaft, a high pressure compressor on the second shaft positioned between the fan and the burner, a high pressure turbine on the second shaft positioned between the burner and the low pressure turbine, and an annular rotary slinger on the second shaft positioned between the high pressure compressor and the high pressure turbine and arranged to sling fuel radially outwardly into the burner.

  16. Passive bypass valve assembly

    SciTech Connect

    Siedlecki, W.F. Jr.

    1992-05-19

    This patent describes a bypass valve assembly for controlling fluid flow in a gas turbine engine. It comprises an annular frame including an outer casing, an inner casing spaced from the outer casing to define a channel for channeling fluid flow and the outer casing including an annular opening therein; a plurality of circumferentially juxtaposed bypass valve doors disposed in the annular opening, each of the valve doors having an inner surface for facing the fluid flowable in the channel, an outer surface, a first end pivotally connected to the frame, and a second end, the doors being positionable in a first position generally parallel to the outer casing, and in a second position inclined relative to the outer casing, the fluid flow flowable against the door inner surface being effective for generating a fluid force on the door; and means for automatically positioning the doors in first and second positions in response to differential pressure across the door, the positioning means providing a torque on the doors for moving the door from the first to the second positions and including torque adjustment means for reducing the torque for at least a portion of travel of the doors from the second to the first positions.

  17. A Typology of UK Slot Machine Gamblers: A Longitudinal Observational and Interview Study

    ERIC Educational Resources Information Center

    Griffiths, Mark D.

    2011-01-01

    Slot machine gambling is a popular leisure activity worldwide yet there has been very little research into different types of slot machine gamblers. Earlier typologies of slot machine gamblers have only concentrated on adolescents in arcade environments. This study presents a new typology of slot machine players based on over 1000 h of participant…

  18. A Typology of UK Slot Machine Gamblers: A Longitudinal Observational and Interview Study

    ERIC Educational Resources Information Center

    Griffiths, Mark D.

    2011-01-01

    Slot machine gambling is a popular leisure activity worldwide yet there has been very little research into different types of slot machine gamblers. Earlier typologies of slot machine gamblers have only concentrated on adolescents in arcade environments. This study presents a new typology of slot machine players based on over 1000 h of participant…

  19. Effects of slotted structures on the nonlinear characteristics of natural convection in a cylinder with an internal concentric slotted annulus

    NASA Astrophysics Data System (ADS)

    Shen, Chunyun; Yang, Mo; Zhang, Yuwen; Li, Zheng

    2016-09-01

    Natural convection in a cylinder with an internally slotted annulus was solved by SIMPLE algorithm, and the effects of different slotted structures on nonlinear characteristics of natural convection were investigated. The results show that the equivalent thermal conductivity Keq increases with Rayleigh number, and reaches the maximum in the vertical orientation. Nonlinear results were obtained by simulating the fluid flow at different conditions. With increasing Rayleigh number, heat transfer is intensified and the state of heat transfer changes from the steady to unsteady. We investigated different slotted structures effects on natural convection, and analyze the corresponding nonlinear characteristics.

  20. 14 CFR 93.221 - Transfer of slots.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Operations at High Density Traffic Airports § 93.221 Transfer of slots. (a) Except as otherwise provided in... high density traffic airport. Transfers, including leases, shall comply with the following conditions...

  1. 14 CFR 93.221 - Transfer of slots.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Operations at High Density Traffic Airports § 93.221 Transfer of slots. (a) Except as otherwise provided in... high density traffic airport. Transfers, including leases, shall comply with the following conditions...

  2. 14 CFR 93.221 - Transfer of slots.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Operations at High Density Traffic Airports § 93.221 Transfer of slots. (a) Except as otherwise provided in... high density traffic airport. Transfers, including leases, shall comply with the following conditions...

  3. 14 CFR 93.221 - Transfer of slots.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Operations at High Density Traffic Airports § 93.221 Transfer of slots. (a) Except as otherwise provided in... high density traffic airport. Transfers, including leases, shall comply with the following conditions...

  4. Slot waveguides with polycrystalline silicon for electrical injection.

    PubMed

    Preston, Kyle; Lipson, Michal

    2009-02-02

    We demonstrate horizontal slot waveguides using high-index layers of polycrystalline and single crystalline silicon separated by a 10 nm layer of silicon dioxide. We measure waveguide propagation loss of 7 dB/cm and a ring resonator intrinsic quality factor of 83,000. The electric field of the optical mode is strongly enhanced in the low-index oxide layer, which can be used to induce a strong modal gain when an active material is embedded in the slot. Both high-index layers are made of electrically conductive silicon which can efficiently transport charge to the slot region. The incorporation of conductive silicon materials with high-Q slot waveguide cavities is a key step for realizing electrical tunneling devices such as electrically pumped silicon-based light sources.

  5. Modeling of Slot Waveguide Sensors Based on Polymeric Materials

    PubMed Central

    Bettotti, Paolo; Pitanti, Alessandro; Rigo, Eveline; De Leonardis, Francesco; Passaro, Vittorio M. N.; Pavesi, Lorenzo

    2011-01-01

    Slot waveguides are very promising for optical sensing applications because of their peculiar spatial mode profile. In this paper we have carried out a detailed analysis of mode confinement properties in slot waveguides realized in very low refractive index materials. We show that the sensitivity of a slot waveguide is not directly related to the refractive index contrast of high and low materials forming the waveguide. Thus, a careful design of the structures allows the realization of high sensitivity devices even in very low refractive index materials (e.g., polymers) to be achieved. Advantages of low index dielectrics in terms of cost, functionalization and ease of fabrication are discussed while keeping both CMOS compatibility and integrable design schemes. Finally, applications of low index slot waveguides as substitute of bulky fiber capillary sensors or in ring resonator architectures are addressed. Theoretical results of this work are relevant to well established polymer technologies. PMID:22164020

  6. Modeling of slot waveguide sensors based on polymeric materials.

    PubMed

    Bettotti, Paolo; Pitanti, Alessandro; Rigo, Eveline; De Leonardis, Francesco; Passaro, Vittorio M N; Pavesi, Lorenzo

    2011-01-01

    Slot waveguides are very promising for optical sensing applications because of their peculiar spatial mode profile. In this paper we have carried out a detailed analysis of mode confinement properties in slot waveguides realized in very low refractive index materials. We show that the sensitivity of a slot waveguide is not directly related to the refractive index contrast of high and low materials forming the waveguide. Thus, a careful design of the structures allows the realization of high sensitivity devices even in very low refractive index materials (e.g., polymers) to be achieved. Advantages of low index dielectrics in terms of cost, functionalization and ease of fabrication are discussed while keeping both CMOS compatibility and integrable design schemes. Finally, applications of low index slot waveguides as substitute of bulky fiber capillary sensors or in ring resonator architectures are addressed. Theoretical results of this work are relevant to well established polymer technologies.

  7. Mimicking glide symmetry dispersion with coupled slot metasurfaces

    NASA Astrophysics Data System (ADS)

    Camacho, Miguel; Mitchell-Thomas, Rhiannon C.; Hibbins, Alastair P.; Sambles, J. Roy; Quevedo-Teruel, Oscar

    2017-09-01

    In this letter, we demonstrate that the dispersion properties associated with glide symmetry can be achieved in systems that only possess reflection symmetry by balancing the influence of two sublattices. We apply this approach to a pair of coupled slots cut into an infinite perfectly conducting plane. Each slot is notched on either edge, with the complete two-slot system having only mirror symmetry. By modifying the relative size of the notches on either side of the slots, we show that a linear dispersion relation with a degeneracy with non-zero group velocity at the Brillouin zone boundary can be achieved. These properties, until now, only found in systems with glide symmetry are numerically and experimentally validated. We also show that these results can be used for the design of ultra-wideband one-dimensional leaky wave antennas in coplanar waveguide technology.

  8. Analysis of a Slot Coupled Coplanar Waveguide Fed Patch Antenna

    NASA Technical Reports Server (NTRS)

    Cheng, Jui-Ching; Dib, Nihad I.; Katehi, Linda P. B.; Simons, Rainee N.; Lee, Richard Q.

    1994-01-01

    A slot-coupled CPW fed patch antenna is analyzed using two different techniques: the Spectral Domain Method and the Finite Difference Time Domain Method. The results from both techniques are in good agreement with experimentally obtained data.

  9. The Allocation of Runway Slots by Auction. Volume III. Theory and Technical Issues for Implementation.

    DTIC Science & Technology

    1980-04-15

    air polution , noise, landside traffic c.)ngestion and so on--dictate a different approach at l_ ast for some congested airports (notably Washington...approaches to slot auctions have not allowed for the inter- dependency of slot values to the air carriers--a single slot for a landing of an aircraft is...slot exchange. 17. Key Woeds II. Distrlbution Stmtome Slot, exchange, auction, trading, air Document is available to the public carriers, allocation

  10. 14 CFR 93.221 - Transfer of slots.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Transfer of slots. 93.221 Section 93.221... obtained by a new entrant or limited incumbent carrier in a lottery held under § 93.225 after June 1, 1991... aircraft of the kind described in § 93.123 (c)(1) or (c)(2) but commuter slots may only be used with...

  11. Effects of geometry on slot-jet film cooling performance

    SciTech Connect

    Hyams, D.G.; McGovern, K.T.; Leylek, J.H.

    1995-10-01

    The physics of the film cooling process for shaped, inclined slot-jets with realistic slot-length-to-width ratios (L/s) is studied for a range of blowing ratio (M) and density ratio (DR) parameters typical of gas turbine operations. For the first time in the open literature, the effect of inlet and exit shaping of the slot-jet on both flow and thermal field characteristics is isolated, and the dominant mechanisms responsible for differences in these characteristics are documented. A previously documented computational methodology was applied for the study of four distinct configurations: (1) slot with straight edges and sharp corners (reference case); (2) slot with shaped inlet region; (3) slot with shaped exit region; and (4) slot with both shaped inlet and exit regions. Detailed field results as well as surface phenomena involving adiabatic film effectiveness ({eta}) and heat transfer coefficient (h) are presented. It is demonstrated that both {eta} and h results are vital in the proper assessment of film cooling performance. All simulations were carried out using a multi-block, unstructured/adaptive grid, fully explicit, time-marching solver with multi-grid, local time stepping, and residual smoothing type acceleration techniques. Special attention was paid to and full documentation provided for: (1) proper modeling of the physical phenomena; (2) exact geometry and high quality grid generation techniques; (3) discretization schemes; and (4) turbulence modeling issues. The key parameters M and DR were varied from 1.0 to 2.0 and 1.5 to 2.0, respectively, to show their influence. Simulations were repeated for slot length-to-width ratio (L/s) of 3.0 and 4.5 in order to explain the effects of this important parameter. Additionally, the performance of two popular turbulence models, standard k-F, and RNG k-E, were studied to establish their ability to handle highly elliptic jet/crossflow interaction type processes.

  12. Slot-Antenna Coupled Microbolometer Arrays for THz Radiation

    DTIC Science & Technology

    2000-09-29

    properties for 2.5THz-CH 3OH laser radiation were microbolometers ), and each bolometer is connected in investigated at room temperature . The detected voltage...configuration of the infrared frequency region, because of its room - single slot antenna coupled microbolometer . The temperature operation and easy...Vol. X 3 slot antenna coupled microbolometer array and a 3 pp.773-776, Jun.1979. 2. D. F. Filpovic, W. Y. Ali-Ahmad, and G. M. Rebeiz, " Millimeter - two

  13. Annular-slot arrays as far-infrared bandpass filters.

    PubMed

    Krug, P A; Dawes, D H; McPhedran, R C; Wright, W; Macfarlane, J C; Whitbourn, L B

    1989-09-01

    Arrays of both annular and square annular slots in a conducting sheet on a dielectric substrate have been fabricated photolithographically. The structures are shown to behave as bandpass filters in the far infrared, with a resonant wavelength slightly larger than the average circumference or perimeter of the slot. The measured far-infrared transmittance of the annular array is approximately 76% of that predicted by theory, while its resonant frequency agrees with theory to within 5%.

  14. FDTD analysis of dielectric-loaded longitudinally slotted rectangular waveguides.

    PubMed

    Al-Rizzo, Hussain M; Younies, Hassan Z; Clark, Ken G; Tranquilla, Jim M

    2003-01-01

    A versatile electromagnetic (EM) computational algorithm, based on the Finite-Difference Time-Domain (FDTD) technique, is developed to analyze longitudinally oriented, square-ended, single slot fixtures and slot-pair configurations cut in the broad wall of a WR-975 guide operating at a frequency of 915 MHz. The finite conductivity of the waveguide walls is accounted for by employing a time-domain Surface-Impedance Boundary Conditions (SIBC) formulation. The proposed FDTD algorithm has been validated against measurements performed on a probe-excited slot cut along the center line of the broad wall of a WR-284 guide and available experimental data for energy coupled from a longitudinal slot pair in the broad wall of a WR-340 guide. Numerical results are-presented to exploit the influence of the constitutive parameters of the processed material as well as protective insulating window slabs mounted on the exterior surface of the slots. Particular attention is given to the resonant length, scattering parameters, and the electric field distribution within lossy objects placed in the near-field region over a range of slot offsets and workloads with extensive results being reported for the first time. It is shown that the FDTD technique can accurately predict the coupling and power absorption characteristics in loads located in the near field zone of the slotted waveguide structures and, therefore, should prove to be a powerful design tool applicable to a wide class of slotted waveguide applicators that may be difficult to analyze using other available techniques.

  15. Double-slot antennas on extended hemispherical dielectric lenses

    NASA Technical Reports Server (NTRS)

    Filipovic, Daniel F.; Gearhart, Steve J.; Kormanyos, Brian K.; Rebeiz, Gabriel M.

    1992-01-01

    An investigation of the coupling efficiencies to a gaussian-beam of a double-slot antenna on a hyperhemispherical lens is presented. It is shown that both lenses couple equally well to an appropriate gaussian beam (about 80 percent). The radiation patterns of both lenses with a double-slot antenna are computed using the ray-tracing method. The experimental radiation patterns are presented and show close agreement to the theoretically computed patterns.

  16. Bypass diode integration

    NASA Technical Reports Server (NTRS)

    Shepard, N. F., Jr.

    1981-01-01

    Protective bypass diodes and mounting configurations which are applicable for use with photovoltaic modules having power dissipation requirements in the 5 to 50 watt range were investigated. Using PN silicon and Schottky diode characterization data on packaged diodes and diode chips, typical diodes were selected as representative for each range of current carrying capacity, an appropriate heat dissipating mounting concept along with its environmental enclosure was defined, and a thermal analysis relating junction temperature as a function of power dissipation was performed. In addition, the heat dissipating mounting device dimensions were varied to determine the effect on junction temperature. The results of the analysis are presented as a set of curves indicating junction temperature as a function of power dissipation for each diode package.

  17. Cardiopulmonary Bypass Without Heparin.

    PubMed

    Rehfeldt, Kent H; Barbara, David W

    2016-03-01

    Due to familiarity, short half-life, ease of monitoring, and the availability of a reversal agent, heparin remains the anticoagulant of choice for cardiac operations requiring cardiopulmonary bypass (CPB). However, occasionally patients require CPB but should not receive heparin, most often because of acute or subacute heparin-induced thrombocytopenia (HIT). In these cases, if it is not feasible to wait for the disappearance of HIT antibodies, an alternative anticoagulant must be selected. A number of non-heparin anticoagulant options have been explored. However, current recommendations suggest the use of a direct thrombin inhibitor such as bivalirudin. This review describes the use of heparin alternatives for the conduct of CPB with a focus on the direct thrombin inhibitors.

  18. Miniaturised reconfigurable window slot antenna using mechanical tuning

    NASA Astrophysics Data System (ADS)

    Beno, A.; Emmanuel, D. S.

    2015-11-01

    A novel design approach of varying the slot width on radiating patch of a microstrip antenna for achieving reconfigurable dual-band operation is proposed. The design of this miniaturised reconfigurable antenna is done without the use of active switches or MEMS. The dual band is obtained by rotating the strips on the patch creating slots and varying the slot width using mechanical tuning. The strip is rotated in angular position from 0° to 90° varying the slot width that alters the resonant frequency of the antenna making it resonate at different frequencies covering the wireless bands for global system for mobile communication, global positioning system, wireless local area network and Bluetooth. This antenna provides a dual-band operation that shifts over the bands depending upon the slot width. This antenna achieves the bandwidth requirement and gain in the bands of operation. The effect of change in slot width on the radiation pattern is also discussed. The prototype antenna is fabricated and tested to prove the proposed concept of design. The measured results are in agreement with the simulated results.

  19. Flowfield Measurements Inside a Boundary-Layer Bleed Slot

    NASA Technical Reports Server (NTRS)

    Davis, D. O.; Willis, B. P.; Hingst, W. R.

    1996-01-01

    An experimental investigation was conducted to determine the flowfield inside a bleed slot used to control an oblique shock-wave and turbulent boundary-layer interaction. The slot was oriented normal to the primary flow direction and had a width of 1.0 cm (primary flow direction) and a length of 2.54 cm and spanned 16.5 cm. The approach boundary layer upstream of the interaction was nominally 3.0 cm thick. Two operating conditions were studied: M = 1.98 with a shock generator deflection angle of 6 deg and M = 2.46 with a shock generator deflection angle of 8 deg. Measurements include surface and flowfield static pressure, pitot pressure, and total mass flow through the slot. The results show that despite an initially two-dimensional interaction for the zero-bleed-flow case, the slot does not remove mass uniformly in the spanwise direction. Inside the slot, the flow is characterized bv two separation regions, which significantly reduce the effective flow area. The upper separation region acts as an aerodynamic throat, resulting in supersonic flow through much of the slot.

  20. Emergent response allocation and outcome ratings in slot machine gambling.

    PubMed

    Dymond, Simon; McCann, Kate; Griffiths, Joanne; Cox, Amanda; Crocker, Victoria

    2012-03-01

    The present study describes a contemporary behavior-analytic model of emergent simulated slot machine gambling. Three laboratory experiments investigated the conditions under which stimuli correlated with different slot machine payout probabilities come to have new, emergent functions without those functions being trained directly. After a successful test for verbal relations (A1-B1-C1 and A2-B2-C2), gamblers and nongamblers were exposed to a task in which high- and low-payout probability functions were established for two slot machines labeled with members of the derived relations (B1 and B2). In Experiment 1, participants provided ratings and chose between concurrently presented slot machines labeled with indirectly related stimuli (C1 and C2). In Experiments 2 and 3, participants made ratings and chose under conditions of nonreinforcement and matched payout probabilities, respectively. Across all three experiments, it was predicted that participants would make more selections of, and give higher liking ratings to, the slot machine indirectly related to the trained high-payout probability machine (C2) than the slot machine indirectly related to the trained low-payout probability machine (C1). Findings supported these predictions. The implications for behavior-analytic research on gambling and the development of verbally based interventions for disordered gambling are discussed.

  1. Surface normal coupling to multiple-slot and cover-slotted silicon nanocrystalline waveguides and ring resonators

    NASA Astrophysics Data System (ADS)

    Covey, John; Chen, Ray T.

    2014-03-01

    Grating couplers are ideal for coupling into the tightly confined propagation modes of semiconductor waveguides. In addition, nonlinear optics has benefited from the sub-diffraction limit confinement of horizontal slot waveguides. By combining these two advancements, slot-based nonlinear optics with mode areas less than 0.02 μm2 can become as routine as twisting fiber connectors together. Surface normal fiber alignment to a chip is also highly desirable from time, cost, and manufacturing considerations. To meet these considerable design challenges, a custom genetic algorithm is created which, starting from purely random designs, creates a unique four stage grating coupler for two novel horizontal slot waveguide platforms. For horizontal multiple-slot waveguides filled with silicon nanocrystal, a theoretical fiber-towaveguide coupling efficiency of 68% is obtained. For thin silicon waveguides clad with optically active silicon nanocrystal, known as cover-slot waveguides, a theoretical fiber-to-waveguide coupling efficiency of 47% is obtained, and 1 dB and 3 dB theoretical bandwidths of 70 nm and 150 nm are obtained, respectively. Both waveguide platforms are fabricated from scratch, and their respective on-chip grating couplers are experimentally measured from a standard single mode fiber array that is mounted surface normally. The horizontal multiple-slot grating coupler achieved an experimental 60% coupling efficiency, and the horizontal cover-slot grating coupler achieved an experimental 38.7% coupling efficiency, with an extrapolated 1 dB bandwidth of 66 nm. This report demonstrates the promise of genetic algorithm-based design by reducing to practice the first large bandwidth vertical grating coupler to a novel silicon nanocrystal horizontal cover-slot waveguide.

  2. CFD simulations of the flow control performance applied for inlet of low drag high-bypass turbofan engine at cross flow regimes

    NASA Astrophysics Data System (ADS)

    Kursakov, I. A.; Kazhan, E. V.; Lysenkov, A. V.; Savelyev, A. A.

    2016-10-01

    Paper describes the optimization procedure for low cruise drag inlet of high-bypass ratio turbofan engine (HBRE). The critical cross-flow velocity when the flow separation on the lee side of the inlet channel occurs is determined. The effciency of different flow control devices used to improve the flow parameters at inlet section cross flow regime is analyzed. Boundary layer suction, bypass slot and vortex generators are considered. It is shown that flow control devices enlarge the stability range of inlet performance at cross flow regimes.

  3. Effect of Slot Combination and Skewed Slot on Electromagnetic Vibration of Capacitor Motor under Load

    NASA Astrophysics Data System (ADS)

    Hirotsuka, Isao; Tsuboi, Kazuo

    The capacitor motor (CRM) is widely used to drive industrial equipments and electric home appliances. Recently, the reduction in the vibration and noise of the CRM has become increasingly important from the standpoint of environmental improvement. However, the electromagnetic vibration of the CRM under load has not been analyzed sufficiently. Therefore, we have studied the electromagnetic vibration of CRM for the purpose of reducing it. In a previous paper, the relationships for a backward magnetic field, the equivalent circuit current, and the vibration of the CRM were clarified. The present paper theoretically and experimentally discusses the effect of the slot combination and skewed slot on the electromagnetic vibration of CRM under load. The primary conclusions are as follows: (1) In the case of 4-pole and 6-pole CRMs, the dominant electromagnetic vibration of CRMs was theoretically attributed to three types of electromagnetic force waves. Two types of electromagnetic force waves are generated: one wave is generated by the interaction of two forward magnetic fluxes, such as those of a three-phase squirrel-cage induction motor, and the other wave is generated under the influence of a backward magnetic flux. (2) The characteristics of dominant electromagnetic vibration depending on load and running capacitor were classified theoretically and experimentally into three types based on the characteristics of the electromagnetic force wave and equivalent circuit current. (3) The influences of magnetic saturation in dominant electromagnetic vibration were verified experimentally and their causes were clarified theoretically in relation to electromagnetic force waves.

  4. Analysis of pesticides in surface water and sediment from Yolo Bypass, California, 2004-2005

    USGS Publications Warehouse

    Smalling, Kelly L.; Orlando, James L.; Kuivila, Kathryn

    2005-01-01

    Inputs to the Yolo Bypass are potential sources of pesticides that could impact critical life stages of native fish. To assess the direct inputs during inundation, pesticide concentrations were analyzed in water, in suspended and bed-sediment samples collected from six source watersheds to the Yolo Bypass, and from three sites within the Bypass in 2004 and 2005. Water samples were collected in February 2004 from the six input sites to the Bypass during the first flood event of the year representing pesticide inputs during high-flow events. Samples were also collected along a transect across the Bypass in early March 2004 and from three sites within the Bypass in the spring of 2004 under low-flow conditions. Low-flow data were used to understand potential pesticide contamination and its effects on native fish if water from these areas were used to flood the Bypass in dry years. To assess loads of pesticides to the Bypass associated with suspended sediments, large-volume water samples were collected during high flows in 2004 and 2005 from three sites, whereas bed sediments were collected from six sites in the fall of 2004 during the dry season. Thirteen current-use pesticides were detected in surface water samples collected during the study. The highest pesticide concentrations detected at the input sites to the Bypass corresponded to the first high-flow event of the year. The highest pesticide concentrations at the two sites sampled within the Bypass during the early spring were detected in mid-April following a major flood event as the water began to subside. The pesticides detected and their concentrations in the surface waters varied by site; however, hexazinone and simazine were detected at all sites and at some of the highest concentrations. Thirteen current-use pesticides and three organochlorine insecticides were detected in bed and suspended sediments collected in 2004 and 2005. The pesticides detected and their concentrations varied by site and sediment

  5. Photovoltaic module bypass diode encapsulation

    NASA Technical Reports Server (NTRS)

    Shepard, N. J., Jr.

    1983-01-01

    The design and processing techniques necessary to incorporate bypass diodes within the module encapsulant are presented. The Semicon PN junction diode cells were selected. Diode junction to heat spreader thermal resistance measurements, performed on a variety of mounted diode chip types and sizes, have yielded values which are consistently below 1 deg C per watt, but show some instability when thermally cycled over the temperature range from -40 to 150 deg C. Three representative experimental modules, each incorporating integral bypass diode/heat spreader assemblies of various sizes, were designed. Thermal testing of these modules enabled the formulation of a recommended heat spreader plate sizing relationship. The production cost of three encapsulated bypass diode/heat spreader assemblies were compared with similarly rated externally mounted packaged diodes. It is concluded that, when proper designed and installed, these bypass diode devices will improve the overall reliability of a terrestrial array over a 20 year design lifetime.

  6. Cerebral oxygenation during cardiopulmonary bypass

    PubMed Central

    Wardle, S; Yoxall, C; Weindling, A

    1998-01-01

    Cerebral fractional oxygen extraction (FOE) was monitored in 30 children, using near infrared spectroscopy during cardiopulmonary bypass, to investigate the effect of hypothermia and circulatory arrest. One group of children (n = 15) underwent profound hypothermia with total circulatory arrest (n = 8) or continuous flow (n =7). Another group (n = 15), of whom only one had circulatory arrest, underwent mild (n = 6) or moderate (n = 9) hypothermia.
 The mean FOE (SD) before bypass was 0.35 (0.12) and this correlated negatively with the preoperative arterial oxygen content (r=−0.58). Between the stage of cooling on bypass and cold bypass there was a reduction in FOE in all groups. Between cold bypass and rewarming there was an increase in FOE only in the groups with continuous flow. In the circulatory arrest group, the FOE remained low during rewarming and was significantly lower than that of the continuous flow group. No patients died and none had neurological abnormalities postoperatively.
 Apparent changes in oxidised cytochrome oxidase concentration were also monitored using near infrared spectroscopy. There was a fall in cytochrome aa3 on starting cardiopulmonary bypass, but there were no significant differences in the changes in cytochrome aa3 between any stage in any of the patient groups.
 Using this non-invasive technique, cooling was shown to reduce cerebral FOE. During rewarming on bypass there was an increase in cerebral FOE only in patients who had had continuous flow bypass. In contrast, the cerebral FOE in those with circulatory arrest remained constant after arrest and during the duration of the study. This may have implications for the timing of hypoxic brain injury.

 PMID:9534672

  7. Modern Design of Resonant Edge-Slot Array Antennas

    NASA Technical Reports Server (NTRS)

    Gosselin, R. B.

    2006-01-01

    Resonant edge-slot (slotted-waveguide) array antennas can now be designed very accurately following a modern computational approach like that followed for some other microwave components. This modern approach makes it possible to design superior antennas at lower cost than was previously possible. Heretofore, the physical and engineering knowledge of resonant edge-slot array antennas had remained immature since they were introduced during World War II. This is because despite their mechanical simplicity, high reliability, and potential for operation with high efficiency, the electromagnetic behavior of resonant edge-slot antennas is very complex. Because engineering design formulas and curves for such antennas are not available in the open literature, designers have been forced to implement iterative processes of fabricating and testing multiple prototypes to derive design databases, each unique for a specific combination of operating frequency and set of waveguide tube dimensions. The expensive, time-consuming nature of these processes has inhibited the use of resonant edge-slot antennas. The present modern approach reduces costs by making it unnecessary to build and test multiple prototypes. As an additional benefit, this approach affords a capability to design an array of slots having different dimensions to taper the antenna illumination to reduce the amplitudes of unwanted side lobes. The heart of the modern approach is the use of the latest commercially available microwave-design software, which implements finite-element models of electromagnetic fields in and around waveguides, antenna elements, and similar components. Instead of building and testing prototypes, one builds a database and constructs design curves from the results of computational simulations for sets of design parameters. The figure shows a resonant edge-slot antenna designed following this approach. Intended for use as part of a radiometer operating at a frequency of 10.7 GHz, this antenna

  8. Polarisation independent silicon-on-insulator slot waveguides

    NASA Astrophysics Data System (ADS)

    Chen, Valerian Hongjie; Ong, Jun Rong; Png, Ching Eng

    2016-11-01

    The minimisation of birefringence, or polarisation mode dispersion, is vital for simplifying and miniaturising photonic components. In this work, we present a systematic study of the slot waveguide geometries required for having zero birefringence (ZB). We show that the rail widths required for ZB are more strongly dependent on the height of the waveguide than on the slot separation. After which, we demonstrate that the ZB geometry is significantly affected by the slanting of the waveguide walls. This paper proceeds to show that within the range studied, one can fix the height, slot, slant angle, and bend radius, and still achieve ZB by varying the widths of both of the rails. Given a fabrication tolerance of 5 nm, we show that a coherence length on the order of a hundred microns can be achieved. We finish by showing that for straight and bent ZB waveguides, having symmetric rails is preferable due to higher tolerances and lower sensitivity to bending. Since any arbitrarily shaped slot waveguide is a combination of both single mode straight and bent waveguides, we have a toolbox from which we can achieve ZB for any given slot and height.

  9. Polarisation independent silicon-on-insulator slot waveguides

    PubMed Central

    Chen, Valerian Hongjie; Ong, Jun Rong; Png, Ching Eng

    2016-01-01

    The minimisation of birefringence, or polarisation mode dispersion, is vital for simplifying and miniaturising photonic components. In this work, we present a systematic study of the slot waveguide geometries required for having zero birefringence (ZB). We show that the rail widths required for ZB are more strongly dependent on the height of the waveguide than on the slot separation. After which, we demonstrate that the ZB geometry is significantly affected by the slanting of the waveguide walls. This paper proceeds to show that within the range studied, one can fix the height, slot, slant angle, and bend radius, and still achieve ZB by varying the widths of both of the rails. Given a fabrication tolerance of 5 nm, we show that a coherence length on the order of a hundred microns can be achieved. We finish by showing that for straight and bent ZB waveguides, having symmetric rails is preferable due to higher tolerances and lower sensitivity to bending. Since any arbitrarily shaped slot waveguide is a combination of both single mode straight and bent waveguides, we have a toolbox from which we can achieve ZB for any given slot and height. PMID:27898089

  10. Progress towards dual vertical slot modulator for millimeter wave photonics

    NASA Astrophysics Data System (ADS)

    Kozacik, Stephen T.; Murakowski, Maciej; Konkol, Matthew; Addya, Suman; Eng, David L. K.; Olbricht, Benjamin C.; Zablocki, Mathew J.; Sharkawy, Ahmed; Murakowski, Janusz; Shi, Shouyuan; Prather, Dennis W.

    2013-03-01

    Dual vertical slot modulators leverage the field enhancement provided by the continuity of the normal electric flux density across a boundary between two dielectrics to increase modal confinement and overlap for the propagating optical and RF waves. This effect is achieved by aligning a conventional silicon-based optical slot waveguide with a titanium dioxide RF slot. The TiO2 has an optical refractive index lower than silicon, but a significantly higher index in the RF regime. The dual slot design confines both the optical and RF modes to the same void between the silicon ribs of the optical slot waveguide. To obtain modulation of the optical signal, the void is filled with an organic electro optic material (OEOM), which offers a high optical non-linearity. The optical and RF refractive index of the OEOM is lower than silicon and can be deposited through spin processing. This design causes an extremely large mode overlap between the optical field and the RF field within the non-linear OEOM material which can result in a device with a low Vπ and a high operational bandwidth. We present work towards achieving various prototypes of the proposed device, and we discuss the fabrication challenges inherent to its design.

  11. Ultrasensitive molecular absorption detection using metal slot antenna arrays.

    PubMed

    Ahn, Kwang Jun; Bahk, Young-Mi; Kim, Dai-Sik; Kyoung, Jisoo; Rotermund, Fabian

    2015-07-27

    We theoretically study the transmission reduction of light passing through absorptive molecules embedded in a periodic metal slot array in a near infrared wavelength regime. From the analytically solved transmitted light, we present a simple relation given by the attenuation length of light at the resonance wavelength of the slot antennas with respect to the spectral width of the resonant transmission peak. This relation clearly explains that the control of the transmission reduction even with very low absorptive materials is possible. We investigate also the transmission reduction by absorptive molecules in a real metallic slot antenna array on a dielectric substrate and compare the results with finite difference time domain calculations. In numerical calculations, we demonstrate that the same amount of transmission reduction by a bulk absorptive material can be achieved only with one-hundredth thickness of the same material when it is embedded in an optimized Fano-resonant slot antenna array. Our relation presented in this study can contribute to label-free chemical and biological sensing as an efficient design and performance criterion for periodic slot antenna arrays.

  12. Static slot testing of conventional lost circulation materials

    SciTech Connect

    Hinkebein, T.E.; Behr, V.L.; Wilde, S.L.

    1983-01-01

    A study of the utility of conventional lost circulation materials and testing methods was performed using a modified API slot tester. Five lost circulation materials were evaluated in 266 tests at both room temperature and temperature-aged conditions simulating expected geothermal environments. A large variation in the maximum pressure (or sealing pressure) the plug could withstand was attributed to nonrepeatability in plug strengths. Plugs were composed to multiple or single particle bridges, with the latter providing stronger, better sealing plugs. Seals occurred on the upstream surface of the slots in all cases. Sealing pressures generally decreased with increasing slot widths and decreasing solids concentration. When the slot width was less than the size of the largest rigid particle in the lost circulation slurry, sealing pressure was maximized. When the slot width was greater than three times the maximum rigid particle size, no significant sealing ability was observed with the conventional materials tested. Additionally, cellulosic lost circulation materials are severely degraded by temperature aging. Mud gellation provided no significant improvement in lost circulation material sealing ability.

  13. Bypass rewiring and robustness of complex networks

    NASA Astrophysics Data System (ADS)

    Park, Junsang; Hahn, Sang Geun

    2016-08-01

    A concept of bypass rewiring is introduced, and random bypass rewiring is analytically and numerically investigated with simulations. Our results show that bypass rewiring makes networks robust against removal of nodes including random failures and attacks. In particular, random bypass rewiring connects all nodes except the removed nodes on an even degree infinite network and makes the percolation threshold 0 for arbitrary occupation probabilities. In our example, the even degree network is more robust than the original network with random bypass rewiring, while the original network is more robust than the even degree networks without random bypass. We propose a greedy bypass rewiring algorithm which guarantees the maximum size of the largest component at each step, assuming which node will be removed next is unknown. The simulation result shows that the greedy bypass rewiring algorithm improves the robustness of the autonomous system of the Internet under attacks more than random bypass rewiring.

  14. Small angle slot divertor concept for long pulse advanced tokamaks

    NASA Astrophysics Data System (ADS)

    Guo, H. Y.; Sang, C. F.; Stangeby, P. C.; Lao, L. L.; Taylor, T. S.; Thomas, D. M.

    2017-04-01

    SOLPS-EIRENE edge code analysis shows that a gas-tight slot divertor geometry with a small-angle (glancing-incidence) target, named the small angle slot (SAS) divertor, can achieve cold, dissipative/detached divertor conditions at relatively low values of plasma density at the outside midplane separatrix. SAS exhibits the following key features: (1) strong enhancement of the buildup of neutral density in a localized region near the plasma strike point on the divertor target; (2) spreading of the cooling front across the divertor target with the slot gradually flaring out from the strike point, thus effectively reducing both heat flux and erosion on the entire divertor target surface. Such a divertor may potentially provide a power and particle handling solution for long pulse advanced tokamaks.

  15. Hydrodynamic characteristics of three rows of vertical slotted wall breakwaters

    NASA Astrophysics Data System (ADS)

    Alsaydalani, Majed O.; Saif, Mohammed A. N.; Helal, Medhat M.

    2017-09-01

    In this study, we examine the hydrodynamic characteristics of three rows of vertical slotted wall breakwaters in which the front and middle walls are permeable and partially immersed in a water channel of constant depth, whereas the third wall is impermeable. The wave-structure interaction and flow behavior of this type of breakwater arrangement are complicated and must be analyzed before breakwaters can be appropriately designed. To study the hydrodynamic breakwater performance, we developed a mathematical model based on the eigenfunction expansion method and a least squares technique for predicting wave interaction with three rows of vertical slotted wall breakwaters. We theoretically examined the wave transmission, reflection, energy loss, wave runup, and wave force under normal regular waves. Comparisons with experimental measurements show that the mathematical model results adequately reproduce most of the important features. The results of this investigation provide a better understanding of the hydrodynamic performance of triple-row vertical slotted wall breakwaters.

  16. Analysis of the Tem Mode Linearly Tapered Slot Antenna

    NASA Technical Reports Server (NTRS)

    Janaswamy, R.; Schaubert, D. H.; Pozar, D. M.

    1985-01-01

    The theoretical analysis of the radiation characteristics of the TEM mode Linearly Tapered Slot Antenna (LTSA) is presented. The theory presented is valid for antennas with air dielectric and forms the basis for analysis of the more popular dielectric-supported antennas. The method of analysis involves two steps. In the first step, the aperture distribution in the flared slot is determined. In the second step, the equivalent magnetic current in the slot is treated as radiating in the presence of a conducting half-plane and the far-field components are obtained. Detailed comparison with experiment is made and excellent agreement is obtained. Design curves for the variation of the 3 dB and 10 dB beamwidths as a function of the antenna length, with the flare angle as a parameter, are presented.

  17. End-loaded crossed-slot radiating elements

    NASA Technical Reports Server (NTRS)

    Manshadi, F.

    1991-01-01

    Three cavity-backed crossed-slot antenna configurations are described that offer simple design, easy frequency tuning, light weight, low loss, and low cost. These antennas are designed for mobile satellite (MSAT) vehicle phased-array applications. The slots in these antennas are end-loaded. The end loading makes the slots effectively longer, and hence reduces their resonant frequency. Therefore, relatively small radiating elements can be achieved for large-angle-scanning phased-array antennas. These antennas have good RF characteristics and provide a relatively wide bandwidth without needing external tuning circuits for impedance matching. Measurements for the return loss and the far-field pattern of these antennas are presented.

  18. A new planar feed for slot spiral antennas

    NASA Technical Reports Server (NTRS)

    Nurnberger, M. W.; Volakis, J. L.

    1995-01-01

    This report presents a new planar, wideband feed network for a slot spiral antenna, and the subsequent design and performance of a VHF antenna utilizing this feed design. Both input impedance and radiation pattern measurements are presented to demonstrate the performance and usefulness of this feed. Almost all previous designs have utilized wire spirals, requiring bulky, non-planar feeds with separate baluns, and large absorbing cavities. The presented slot spiral antenna feed integrates the balun into the structure of the slot spiral antenna, making the antenna and feed planar. This greatly simplifies the design and construction of the antenna, in addition to providing repeatable accuracy. It also allows the use of a very shallow reflecting cavity for conformal applications. Finally, this feeding approach now makes many of the known miniaturization techniques viable options.

  19. Flow characteristics in boundary layer bleed slots with plenum

    NASA Technical Reports Server (NTRS)

    Hamed, A.; Yeuan, J. J.; Jun, Y. D.

    1995-01-01

    Numerical simulations were conducted to investigate the performance characteristics of bleed through normal slots and its effect on the turbulent boundary layer development under zero and strong adverse pressure gradient caused by incident oblique shock. The solution to the compressible Navier-Stokes and k-epsilon equations was obtained in a domain that includes the regions inside the bleed slot and plenum in addition to the external flow. The computational results demonstrate the interactions between the plenum and bleed flow and the effect of incident shock on the boundary layer development downstream. The computed results agree with the experimentally measured pitot and static pressure distribution inside the slot. The bleed mass flow without incident shock was underpredicted over the range of plenum pressures. The computations predicted the measured increase in bleed mass flow with incident shock.

  20. Tunable single-mode slot waveguide quantum cascade lasers

    SciTech Connect

    Meng, Bo; Tao, Jin; Quan Zeng, Yong; Wu, Sheng; Jie Wang, Qi

    2014-05-19

    We report experimental demonstration of tunable, monolithic, single-mode quantum cascade lasers (QCLs) at ∼10 μm with a two-section etched slot structure. A single-mode tuning range of 77 cm{sup −1} (785 nm), corresponding to ∼7.8% of the relative tuning range, was realized with a ∼20 dB side mode suppression ratio within the whole tuning range. Compared with integrated distributed feedback QCLs, our devices have the advantages of easy fabrication and a broader tuning range. Further theoretical analyses and numerical simulations show that it is possible to achieve a broad continuous tuning range by optimizing the slot structures. The proposed slot-waveguide design could provide an alternative but simple approach to the existing tuning schemes for realizing broadly continuous tunable single-mode QCLs.

  1. Thermally tunable slot-coupled dielectric resonator antenna

    NASA Astrophysics Data System (ADS)

    Bi, Ke; Chen, Cong; Wang, Qingmin; Liu, Wenjun; Hao, Yanan; Gao, Xinlu; Huang, Shanguo; Lei, Ming

    2017-02-01

    A thermally tunable slot-coupled dielectric resonator antenna (DRA) has been designed and prepared by placing a thermosensitive ceramic resonator onto the slot. Typical magnetic resonance occurs in the resonator, which is closely related to its dielectric constant. Because the dielectric constant of the ceramic resonator decreases as the temperature increases, the resonance frequency of the proposed DRA increases as the temperature increases. The simulated results are in good agreement with the measured ones, which confirms the thermally tunable behavior. This approach provides a way for designing the frequency tunable antennas.

  2. Frequency Reconfigurable Hybrid Slot Antenna Using PIN Diodes

    NASA Astrophysics Data System (ADS)

    Yang, Xiaolin; Sheng, Lili; Lin, Jiancheng; Chen, Gang

    2015-11-01

    This paper introduces a frequency reconfigurable hybrid slot antenna fed by coplanar waveguide (CPW) without complex bias network and DC blocking capacitor chips. In order to add reconfigurablility to the antenna, the PIN diodes are equipped in the slots. The antenna is capable of frequency switching at six different frequency bands between 1.7 GHz to 2.5 GHz, which can be used in multiradio wireless systems, such as DCS-1800, PCS1900, UMTS, Wibro and Bluetooth bands. The simulated and measured return loss, peak gain, together with the radiation patterns are presented and compared. Especially, the radiation patterns are stable at different frequency.

  3. Clean Air Slots Amid Dense Atmospheric Pollution in Southern Africa

    NASA Technical Reports Server (NTRS)

    Hobbs, Peter V.

    2003-01-01

    During the flights of the University of Washington's Convair-580 in the Southern African Regional Science Initiative (SAFARI 2000) in southern Africa, a phenomenon was observed that has not been reported previously. This was the occurrence of thin layers of remarkably clean air, sandwiched between heavily polluted air, which persisted for many hours during the day. Photographs are shown of these clean air slots (CAS), and particle concentrations and light scattering coefficients in and around such slot are presented. An explanation is proposed for the propensity of CAS to form in southern Africa during the dry season.

  4. Synchronization in air-slot photonic crystal optomechanical oscillators

    NASA Astrophysics Data System (ADS)

    Huang, Yongjun; Wu, Jiagui; Flores, Jaime Gonzalo Flor; Yu, Mingbin; Kwong, Dim-Lee; Wen, Guangjun; Wong, Chee Wei

    2017-03-01

    In this Letter, we report observations for the optomechanical oscillator (OMO) synchronization in an air-slot photonic crystal (PhC) cavity driven by a single laser source. Two very-close mechanical modes are found in the air-slot PhC OMO cavity and can be locked to each other at drive powers above the threshold with different detunings. The improvement in phase noise (-70 dBc/Hz at 10 kHz offset) for the synchronized OMO is reported as well. The stable frequency tones obtained open a path toward reconfigurable synchronized oscillator networks.

  5. Consequences of Slot Transactions on Airport Congestion and Environmental Protection

    NASA Technical Reports Server (NTRS)

    Abeyratne, Ruwantissa I.R.

    2000-01-01

    Recent trends in the liberalization of market access by many commercial airlines have opened the skies to virtually unlimited flights between many countries. However, this liberalization is stultified by the lack of airport capacity to accommodate the many flights that are generated by demand for capacity. Accordingly, the allocation of slots for open skies airlines remain dependent on the expansion and effective management of airport capacity. This article examines the ramifications of slot allocation on traffic peaking at airports and environmental concerns, which may emerge with this activity.

  6. Slot-Antenna/Permanent-Magnet Device for Generating Plasma

    NASA Technical Reports Server (NTRS)

    Foster, John E.

    2007-01-01

    A device that includes a rectangular-waveguide/slot-antenna structure and permanent magnets has been devised as a means of generating a substantially uniform plasma over a relatively large area, using relatively low input power and a low gas flow rate. The device utilizes electron cyclotron resonance (ECR) excited by microwave power to efficiently generate plasma in a manner that is completely electrodeless in the sense that, in principle, there is no electrical contact between the plasma and the antenna. Plasmas generated by devices like this one are suitable for use as sources of ions and/or electrons for diverse material-processing applications (e.g., etching or deposition) and for ion thrusters. The absence of plasma/electrode contact essentially prevents plasma-induced erosion of the antenna, thereby also helping to minimize contamination of the plasma and of objects exposed to the plasma. Consequently, the operational lifetime of the rectangular-waveguide/ slot-antenna structure is long and the lifetime of the plasma source is limited by the lifetime of the associated charged-particle-extraction grid (if used) or the lifetime of the microwave power source. The device includes a series of matched radiating slot pairs that are distributed along the length of a plasma-source discharge chamber (see figure). This arrangement enables the production of plasma in a distributed fashion, thereby giving rise to a uniform plasma profile. A uniform plasma profile is necessary for uniformity in any electron- or ion-extraction electrostatic optics. The slotted configuration of the waveguide/ antenna structure makes the device scalable to larger areas and higher powers. All that is needed for scaling up is the attachment of additional matched radiating slots along the length of the discharge chamber. If it is desired to make the power per slot remain constant in scaling up, then the input microwave power must be increased accordingly. Unlike in prior ECR microwave plasma

  7. Active CPW-fed slot antennas for power combining applications

    NASA Technical Reports Server (NTRS)

    Kormanyos, Brian K.; Rebeiz, Gabriel M.

    1992-01-01

    We have combined integrated circuit antenna technology with microwave oscillator design to build an active slot-oscillator. The design is planar, does not require via holes and is compatible with monolithic transistor technology. The CPW-fed antenna impedance is calculated using a full-wave analysis technique. Slot-oscillators were built at 7, 13, and 22 GHz, and the predicted oscillation frequencies agree well with experiments. The design is easily scaled to millimeter-wave frequencies and can be extended to power combining arrays.

  8. Broadband spin-wave delay lines with slot antennas

    NASA Astrophysics Data System (ADS)

    Etko, Yu. L.; Ustinov, A. B.

    2011-11-01

    A planar spin-wave delay line with slot antennas based on an yttrium iron garnet (YIG) film has been experimentally studied. A specific feature of the proposed device is a relatively large (about 1.8 GHz) microwave bandwidth. Within this band, the signal delay time can be smoothly controlled from 4 to 18 ns. The central frequency can be tuned by an external magnetic field within 5-9 GHz. It is demonstrated that, using slot antennas and relatively thick ferromagnetic films, it is possible to achieve a significant increase in the microwave bandwidth of spin-wave devices.

  9. Extreme optical confinement in a slotted photonic crystal waveguide

    SciTech Connect

    Caër, Charles; Le Roux, Xavier; Cassan, Eric; Combrié, Sylvain De Rossi, Alfredo

    2014-09-22

    Using Optical Coherence Tomography, we measure the attenuation of slow light modes in slotted photonic crystal waveguides. When the group index is close to 20, the attenuation is below 300 dB cm{sup −1}. Here, the optical confinement in the empty slot is very strong, corresponding to an ultra-small effective cross section of 0.02 μm{sup 2}. This is nearly 10 times below the diffraction limit at λ = 1.5 μm, and it enables an effective interaction with a very small volume of functionalized matter.

  10. A twin slot antenna on a layered substrate coupled to a microstrip feed line

    NASA Astrophysics Data System (ADS)

    Rogers, R. L.; Neikirk, D. P.; Itoh, T.; Wentworth, S. M.

    1990-10-01

    A method is described for calculating the input impedance as seen by the detector for a twin slot antenna structure. This technique is then used to analyze several twin slot antenna configurations, leading to improved performance.

  11. Effect of Exit-Slot Position and Opening on the Available Cooling Pressure for NACA Nose-Slot Cowlings

    NASA Technical Reports Server (NTRS)

    Stickle, George W; Naiman, Irven; Crigler, John L

    1940-01-01

    Report presents the results of an investigation of full-scale nose-slot cowlings conducted in the NACA 20-foot wind tunnel to furnish information on the pressure drop available for cooling. Engine conductances from 0 to 0.12 and exit-slot conductances from 0 to 0.30 were covered. Two basic nose shapes were tested to determine the effect of the radius of curvature of the nose contour; the nose shape with the smaller radius of curvature gave the higher pressure drop across the engine. The best axial location of the slot for low-speed operation was found to be in the region of maximum negative pressure for the basic shape for the particular operating condition. The effect of the pressure operating condition on the available cooling pressure is shown.

  12. Carotid bypass for carotid occlusion.

    PubMed

    Hage, Ziad A; Behbahani, Mandana; Amin-Hanjani, Sepideh; Charbel, Fady T

    2015-07-01

    The 2-year risk of ipsilateral ischemic stroke following internal carotid artery occlusion (ICAO) in a patient undergoing maximal medical therapy is 5-8% per year. While medical therapy may reduce the risk of stroke, it does not completely eliminate it. Since the 1985 extracranial-intracranial (EC-IC) bypass study, additional trials have been conducted to further investigate the usefulness of EC-IC bypass surgery in more selected patients with cerebral ischemia and impaired hemodynamic reserve. These important studies will be briefly reviewed in this article, as well as a discussion regarding the utility of bypass surgery for ICAO in current clinical practice. In addition, a short discussion regarding the pathophysiology of carotid occlusion will be presented. We will also highlight our own institutional patient selection criteria based on the latest methods for hemodynamic assessment, as well as our intraoperative flow assisted surgical techniques (FAST), and post-operative patient follow-up.

  13. Viscous effects on the resonance of a slotted wind tunnel using finite elements

    NASA Technical Reports Server (NTRS)

    Lee, IN

    1988-01-01

    Prompted by the fact that wind tunnel flutter and oscillatory airload measurements are affected by acoustic vibration mode coupling when the model frequency lies near a wind tunnel resonance frequency, a numerical method has been developed for design sensitivity analysis. Solid curves represent the resonant frequency for the slot, without considering the slot's viscosity. While the viscosity effect decreases with increasing slot width, the viscosity effect also decreases as the slot width approaches zero.

  14. An analysis of pressure driven cross-flow through a long slot connecting two parallel channels

    SciTech Connect

    Shadday, M.A. Jr.

    1992-12-31

    Cross-flow between two parallel channels that were connected by a long narrow slot has been measured. The data was presented primarily in terms of transverse resistance coefficients. This data has been analyzed with momentum balances applied to both the axial and transverse components of the slot flow. The importance of wall friction to the slot flow and the necessity of calculating the axial component of the slot flow is demonstrated.

  15. 16. VIEW OF BULKHEAD IN FISH HOLD. NOTE SCANTLINGS WHICH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. VIEW OF BULKHEAD IN FISH HOLD. NOTE SCANTLINGS WHICH FORM A VERTICAL SLOT FOR BOARDS. THESE BOARDS ALSO ENABLED THE FISHERMAN TO SORT THE CATCH BY SPECIES INTO VARIOUS COMPARTMENTS. THE HOLES AT THE BASE OF THE BULKHEAD ALLOWED WATER FROM MELTED ICE TO DRAIN OUT OF THE COMPARTMENT. - Auxiliary Fishing Schooner "Evelina M. Goulart", Essex Shipbuilding Museum, 66 Main Street, Essex, Essex County, MA

  16. Coronary Artery Disease: Angioplasty or Bypass Surgery?

    MedlinePlus

    Coronary artery disease: Angioplasty or bypass surgery? I'm getting a cardiac catheterization. If blockages are found, ... angioplasty or bypass surgery? Answers from Rekha Mankad, M.D. During cardiac catheterization, your doctor will examine ...

  17. Secondary and College LD Bypass Strategies.

    ERIC Educational Resources Information Center

    Mosby, Robert J.

    1981-01-01

    The author describes the Developmental By-Pass (DBP) Instructional technology for teaching secondary and college learning disabled (LD) students by allowing students to bypass ordering and organizational deficits. (SB)

  18. Types of Coronary Artery Bypass Grafting

    MedlinePlus

    ... from the NHLBI on Twitter. Types of Coronary Artery Bypass Grafting There are several types of coronary ... for you based on your needs. Traditional Coronary Artery Bypass Grafting Traditional CABG is used when at ...

  19. Psychological Effects of Intestinal Bypass Surgery.

    ERIC Educational Resources Information Center

    Wampler, Richard S.; And Others

    1980-01-01

    Preoperative and postoperative intestinal bypass patients were evaluated. Results suggest that postoperative bypass patients have improved psychological health and an increased sense of freedom and well-being but may need assistance in improving self-concepts. (Author)

  20. Technology Solutions Case Study: Preventing Thermal Bypass

    SciTech Connect

    none,

    2012-10-01

    This project highlights the importance of continuous air barriers in full alignment with insulation to prevent thermal bypasses and achieve high energy performance, and recommends use of ENERGY STAR's Thermal Bypass Inspection Checklist.

  1. Slow Wave Vane Structure with Elliptical Cross-Section Slots, an Analysis

    NASA Technical Reports Server (NTRS)

    Kosmahl, Henry G.

    1994-01-01

    Mathematical analysis of the wave equation in cylinders with elliptical cross-section slots was performed. Compared to slow wave structures with rectangular slots higher impedance and lower power dissipation losses are evident. These features could lead to improved designs of traveling wave magnetrons and gigahertz backward-wave oscillators as well as linear traveling wave tubes with relatively shallow slots.

  2. Hydrodynamic Performance of a Dual-Slotted Circulation Control Wing of Low-Aspect Ratio

    DTIC Science & Technology

    2006-12-01

    experimental effort was undertaken to document the performance of a low-aspect ratio hydrofoil with trailing edge blowing across a Coanda surface in a...CCFoil, upper slot blowing, Coanda surface, tip vortex, and lighting vortex at 80% span shown...62 Figure 70. Surface cavitation on Coanda Surface, close-up of the slot flow, incpetion behind slot lip face

  3. 14. PERSPECTIVE VIEW INTO CENTER SECTION OF STARBOARD FISH HOLD. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. PERSPECTIVE VIEW INTO CENTER SECTION OF STARBOARD FISH HOLD. NOTE THAT THE CONCRETE FLOOR IS CARRIED UP THE HULL, WELL INTO THE CEILING. EACH HOLD COULD BE PARTITIONED INTO SECTIONS USING WOOD BOARDS WHICH FIT INTO SLOTS FORMED BY SCANTLINGS. NOTE ROUND OPENING AT TOP LEFT OF PHOTOGRAPH. SIMILAR OPENINGS OVER OTHER AREAS OF THE HOLD WERE USED TO DROP FISH FROM THE DECK INTO THE ICE-FILLED HOLD. FISH WOULD BE SORTED BY SPECIES AND DROPPED TO DIFFERENT PARTS OF THE HOLD. - Auxiliary Fishing Schooner "Evelina M. Goulart", Essex Shipbuilding Museum, 66 Main Street, Essex, Essex County, MA

  4. 14 CFR 93.215 - Initial allocation of slots.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Initial allocation of slots. 93.215 Section...) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Allocation of Commuter and Air... 16, 1985 is divided among different operators, by day of the week, or otherwise, as evidenced...

  5. 14 CFR 93.224 - Return of slots.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Return of slots. 93.224 Section 93.224... returned under this subpart, the holder must notify the office specified in § 93.221(a)(1) in writing of... operators by notifying the office specified in § 93.221(a)(1) in writing. ...

  6. Realistic Free-Spins Features Increase Preference for Slot Machines.

    PubMed

    Taylor, Lorance F; Macaskill, Anne C; Hunt, Maree J

    2017-06-01

    Despite increasing research into how the structural characteristics of slot machines influence gambling behaviour there have been no experimental investigations into the effect of free-spins bonus features-a structural characteristic that is commonly central to the design of slot machines. This series of three experiments investigated the free-spins feature using slot machine simulations to determine whether participants allocate more wagers to a machine with free spins, and, which components of free-spins features drive this preference. In each experiment, participants were exposed to two computer-simulated slot machines-one with a free-spins feature or similar bonus feature and one without. Participants then completed a testing phase where they could freely switch between the two machines. In Experiment 1, participants did not prefer the machine with a simple free-spins feature. In Experiment 2 the free-spins feature incorporated additional elements such as sounds, animations, and an increased win frequency; participants preferred to gamble on this machine. The Experiment 3 "bonus feature" machine resembled the free spins machine in Experiment 2 except spins were not free; participants showed a clear preference for this machine also. These findings indicate that (1) free-spins features have a major influence over machine choice and (2) the "freeness" of the free-spins bonus features is not an important driver of preference, contrary to self-report and interview research with gamblers.

  7. Reconfigurable tapered coaxial slot antenna for hepatic microwave ablation.

    PubMed

    Malhotra, Neeru; Marwaha, Anupma; Kumar, Ajay

    2016-01-01

    Microwave ablation is rapidly being rediscovered and developed for treating many cancers of liver, lung, kidney and bone, as well as arrhythmias and other medical conditions. The microwaves ablate tissue by heating it to cytotoxic temperatures. The microwave antenna design suffers the challenges of effective coupling and penetration into body tissues, uncontrolled power deposition due to applicator construction limitations affecting uniform heating of target region, and narrowband operation leading to mismatch for many patients and detrimental heating. To meet out the requirements of wideband operation and localized lesion reconfigurable linearly tapered slot interstitial wideband antenna has been proposed for working in the 1.38 GHz to 4.31 GHz frequency band. The performance of the antenna is evaluated by using FEM-based HFSS software. The slot height and taper height are reconfigured for parametric analysis achieving maximum impedance matching and spherical ablation zone without requiring any additional adjustable structures. The tapering of the slot in coaxial antenna generates current distribution at the edges of the slot for maximizing specific absorption rate.

  8. Mixing layer control for tangential slot injection in turbulent flows

    NASA Technical Reports Server (NTRS)

    Mcinville, R. M.; Goodman, W. L.; Hassan, H. A.

    1985-01-01

    Tangential injection into turbulent flows is one of the most promising methods of minimizing skin friction and providing thermal protection. The technique also has application to laser hardening. The effectiveness of the injected material can be increased if the spreading rate of the resulting mixing region can be reduced. Various techniques which have been shown to be effective in manipulating the rate of growth of mixing layers under certain conditions have been applied to a slot configuration having a thick external turbulent boundary layer. These include geometry modifications to the slot lip trailing edge and acoustic excitation of the slot exit plane over a wide range of frequencies. Neither of these approaches produced any noticeable effect on the downstream evolution of the mixing layer. This lack of effectiveness is attributed to the dominating influence of the well-developed incoming turbulent boundary layer. The placement of large-eddy breakup devices in this boundary layer upstream of the injection point did produce significantly lower velocities in the near-wall region of the flow downstream of the slot exit.

  9. Detail of one way mirror, mail slot, and electrical box ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail of one way mirror, mail slot, and electrical box at sentry post no. 3, top of east stairs near the end of second floor corridor - March Air Force Base, Strategic Air Command, Combat Operations Center, 5220 Riverside Drive, Moreno Valley, Riverside County, CA

  10. Forebody Tangential Slot Blowing on an Aircraft Geometry

    NASA Technical Reports Server (NTRS)

    Gee, Ken; Rizk, Yehia M.; Schiff, Lewis B.

    1994-01-01

    The effect of forebody tangential slot blowing on the flowfield about an F/A-18 aircraft is investigated numerically using solutions of the Navier-Stokes equations. Computed solutions are obtained for an aircraft geometry which includes the fuselage, a wing with deflected leading-edge flap, empennage, and a faired-over engine inlet. The computational slot geometry corresponds to that used in full-scale wind-tunnel tests. Solutions are computed using flight test conditions and jet mass flow ratios equivalent to wind-tunnel test conditions. The effect of slot location is analyzed by computing two nontime-accurate solutions with a 16-in. slot located 3 in. and 11 in. aft of the nose of the aircraft. These computations resolve the trends observed in the full-scale wind-tunnel test data. The flow aft of the leading-edge extension vortex burst is unsteady. A time-accurate solution is obtained to investigate the flow characteristics aft of the vortex burst, including the effect of blowing on tail buffet.

  11. Double Mine Building (N) wall showing clerestory slot windows opening ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Double Mine Building (N) wall showing clerestory slot windows opening above level of main roof. Note structure is built on poured concrete foundation partly buried in hillside; view in southeast - Fort McKinley, Double Mine Building, East side of East Side Drive, approximately 125 feet south of Weymouth Way, Great Diamond Island, Portland, Cumberland County, ME

  12. Loaded cavity-backed slot (LCBS) antennas for Reentry Vehicles

    SciTech Connect

    Sena, M.D.

    1992-09-01

    This report describes the linearly-polarized, loaded cavity-backed slot (LCBS) antenna developed for Reentry Vehicles (RVs) and the development process used by the Antenna Development Department. It includes typical antenna engineering design considerations or requirements, fabrication/assembly process, and performance characteristics. Antenna design theory is reduced to the basic concepts useful in designing LCBS antennas for reentry vehicles.

  13. Impedance Matching of Tapered Slot Antenna using a Dielectric Transformer

    NASA Technical Reports Server (NTRS)

    Simons, R. N.; Lee, R. Q.

    1998-01-01

    A new impedance matching technique for tapered slot antennas using a dielectric transformer is presented. The technique is demonstrated by measuring the input impedance, Voltage Standing Wave Ratio (VSWR) and the gain of a Vivaldi antenna (VA). Measured results at Ka-Band frequencies are presented and discussed.

  14. Bridge Inductance of Induction Motor with Closed Rotor Slots

    NASA Astrophysics Data System (ADS)

    Matsushita, Makoto; Ishibashi, Fuminori; Suzuki, Takao; Noda, Shinichi

    Closed rotor slots are widely employed in low-power squirrel-cage induction motors with die-cast aluminum cage rotors. Die-cast aluminum cages with closed rotor slots can be manufactured commercially. They help reduce flux pulsation in air gaps, attenuate acoustic noises, and achieve high efficiency. However, it is difficult to calculate bridge inductance of a closed rotor slot accurately because the main flux passes through the bridge and iron saturation can be achieved depending upon the bar current. In this study, bridge inductance was investigated by using a search coil and by FEM analysis and conventional equations. The bridge flux density and the bridge linkage flux were measured by using 4P-0.75kW motor with closed rotor slots, and the bridge inductance was calculated as a function of rotor bar current. The bridge inductance was also analyzed by FEM, and the results were analytically checked by using the calculated conventional equations. From these analyses, it is seen that the measured values of the bridge inductance are in good agreement with the values calculated by FEM and conventional methods. It is verified that the bridge inductance shows a trend similar to that of the μ-H curve of the rotor steel sheet.

  15. Slotting Fins of Heat Exchangers to Provide Thermal Breaks

    NASA Technical Reports Server (NTRS)

    Scull, Timothy D.

    2003-01-01

    Heat exchangers that include slotted fins (in contradistinction to continuous fins) have been invented. The slotting of the fins provides thermal breaks that reduce thermal conduction along flow paths (longitudinal thermal conduction), which reduces heat-transfer efficiency. By increasing the ratio between transverse thermal conduction (the desired heat-transfer conduction) and longitudinal thermal conduction, slotting of the fins can be exploited to (1) increase heat-transfer efficiency (thereby reducing operating cost) for a given heat-exchanger length or to (2) reduce the length (thereby reducing the weight and/or cost) of the heat exchanger needed to obtain a given heat transfer efficiency. By reducing the length of a heat exchanger, one can reduce the pressure drop associated with the flow through it. In a case in which slotting enables the use of fins with thermal conductivity greater than could otherwise be tolerated on the basis of longitudinal thermal conduction, one can exploit the conductivity to make the fins longer (in the transverse direction) than they otherwise could be, thereby making it possible to make a heat exchanger that contains fewer channels and therefore, that weighs less, contains fewer potential leak paths, and can be constructed from fewer parts and, hence, reduced cost.

  16. Light propagation in strip and slot waveguide arrays for sensing

    NASA Astrophysics Data System (ADS)

    Ma, Qingyan; Qi, Fan; Wang, Yufei; Liu, Zhishuang; Zheng, Wanhua

    2016-11-01

    Light propagation in strip and slot waveguide arrays for sensing are proposed and analyzed with a new theory of quantum walk. The waveguide arrays are designed on silicon-on-insulator and can be fabricated with mature and cost-efficient complementary metal-oxide semiconductor technology. A new slot waveguide array modified by conventional strip waveguide array with electric field mainly confined in the cladding region is investigated. Quantum walks have an exact mapping to classical phenomena as verified by experiments using bright laser light, so that they are introduced in our work as theoretical foundation. We take the width of waveguide of 450 nm and the coupling distance of 200 nm for strip waveguide array, and 420 nm and 180 nm for slot waveguide array, but with a 100nm slot in the center of waveguide. At last the waveguide array covered by a thin layer of graphene is investigated, which brings higher sensing property as well as a much better biocompatibility. With the monochrome light injection the intensity distribution at the end of the arrays changes with the refractive index of the sensing area (cladding region) and it can be explained by quantum walks theory. The designed waveguide arrays can possess compact footprint and high refractive index resolution, reaching 1E-11 RIU theoretically.

  17. Development of infrared detector with slot antenna-coupled microbolometer

    NASA Astrophysics Data System (ADS)

    Son, Kosol; Kislov, Nikolai; Wang, Jing

    2010-04-01

    The current state-of-the-art infrared detection technology requires either exotic materials or cryogenic conditions to perform its duty. Implementing infrared detection by coupling infrared tuned antenna with a micro-bolometer offers a promising technological platform for mass production of un-cooled infrared detectors and imaging arrays. The design, fabrication, and characterization of a planar slotted antenna have been demonstrated on a thin silicon dioxide (SiO2) membrane for infrared detection. The planar slotted antenna was chosen due to its ease of fabrication and greater fabrication tolerance, higher gain and greater bandwidth coveted for the infrared applications. The employment of the SiO2 membrane technology mitigates the losses due to surface waves generated as the radiation coupling into the substrates. In addition, by retaining the membrane thickness to be less than a wavelength, the amount of interference is greatly reduced. A strategically designed planar slotted dipole antenna is implemented along with an integrated direct current (DC) block enabled by co-fabricated on-chip capacitors between the two DC patches to separate DC and high frequency signals without the need for sub-micron DC separation line. As a result of this revision, standard UV photolithography instead of e-beam lithography can be used to fabricate the infrared detectors for mass production. This research is considered as an important step toward our main goal, which is developing ultrafast infrared detector by coupling a planar slotted antenna with a metal insulator metal (MIM) tunneling diode.

  18. Tunable Reduced Size Planar Folded Slot Antenna Utilizing Varactor Diodes

    NASA Technical Reports Server (NTRS)

    Scardelletti, Maximilian C.; Ponchak, George E.; Jordan, Jennifer L.; Jastram, Nathan; Mahaffey, Joshua V.

    2010-01-01

    A tunable folded slot antenna that utilizes varactor diodes is presented. The antenna is fabricated on Rogers 6006 Duriod with a dielectric constant and thickness of 6.15 and 635 m, respectively. A copper cladding layer of 17 m defines the antenna on the top side (no ground on backside). The antenna is fed with a CPW 50 (Omega) feed line, has a center frequency of 3 GHz, and incorporates Micrometrics microwave hyper-abrupt 500MHV varactors to tune the resonant frequency. The varactors have a capacitance range of 2.52 pF at 0 V to 0.4 pF at 20 V; they are placed across the radiating slot of the antenna. The tunable 10 dB bandwidth of the 3 GHz antenna is 150 MHz. The varactors also reduce the size of the antenna by 30% by capacitively loading the resonating slot line. At the center frequency, 3 GHz, the antenna has a measured return loss of 44 dB and a gain of 1.6 dBi. Full-wave electromagnetic simulations using HFSS are presented that validate the measured data. Index Terms capacitive loading, Duriod, folded slot antenna, varactor.

  19. Linearly tapered slot antenna circular array for mobile communications

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.; Kelly, Eron; Lee, Richard Q.; Taub, Susan R.

    1993-01-01

    The design, fabrication and testing of a conformal K-band circular array is presented. The array consists of sixteen linearly tapered slot antennas (LTSA). It is fed by a 1:16 microstrip line power splitter via electromagnetic coupling. The array has an omni-directional pattern in the azimuth plane. In the elevation plane the beam is displaced above the horizon.

  20. 14 CFR 93.225 - Lottery of available slots.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Lottery of available slots. 93.225 Section 93.225 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED... lottery is open to each U.S. air carrier or commuter operator operating at the airport and...

  1. 14 CFR 93.225 - Lottery of available slots.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 2 2014-01-01 2014-01-01 false Lottery of available slots. 93.225 Section 93.225 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED... lottery is open to each U.S. air carrier or commuter operator operating at the airport and...

  2. 12. INTERIOR VIEW OF SINGLE BAY SLOTTED TYPE FURNACE (LEFT) ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. INTERIOR VIEW OF SINGLE BAY SLOTTED TYPE FURNACE (LEFT) AND CHAMBERSBURG DROP HAMMER OPERATED BY JEFF HOHMAN (RIGHT); THE FURNACE IS USED TO PRE-HEAT THE STEEL PRIOR TO FORGING, TOOL IS POST HOLE DIGGER WITH TAMPING BAR - Warwood Tool Company, Foot of Nineteenth Street, Wheeling, Ohio County, WV

  3. Altering the "Near-Miss" Effect in Slot Machine Gamblers

    ERIC Educational Resources Information Center

    Dixon, Mark R.; Nastally, Becky L.; Jackson, James E.; Habib, Reza

    2009-01-01

    This study investigated the potential for recreational gamblers to respond as if certain types of losing slot machine outcomes were actually closer to a win than others (termed the "near-miss effect"). Exposure to conditional discrimination training and testing disrupted this effect for 10 of the 16 participants. These 10 participants demonstrated…

  4. Development of the NACA slot-lip aileron

    NASA Technical Reports Server (NTRS)

    Weick, Fred E; Shortal, Joseph A

    1935-01-01

    An investigation of the undesirable delayed action, or lag, of the spoiler-type lateral control device led to the development of the NACA slot-lip aileron. The tests were made in the 7- by 10-foot wind tunnel with a 4- by 8-foot wing hinged at the tunnel jet boundary and taken of the motion of the control device under test and of the resulting wing motion. First, the lag, as affected by the fore-and-aft location of retractable ailerons or spoilers was determined. The lag was found to increase regularly as the spoiler was moved from the rear of the wing toward the front. Then a combination of spoilers and fixed slot was developed that, with the spoiler retracting into the forward part of the slot, reduced the time lag to a negligible value. In addition, an arrangement was developed using a hinged aileron-type flap as the upper portion, or lip, of a slot through the wing. This arrangement appears to be usable as a form of lateral control device that shows promise of giving improved control and stability at the high angles of attack through stall, with negligible lag, low control forces, and relatively simple construction.

  5. 30 CFR 77.302 - Bypass stacks.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ....302 Bypass stacks. Thermal dryer systems shall include a bypass stack, relief stack or individual discharge stack provided with automatic venting which will permit gases from the dryer heating unit to bypass the heating chamber and vent to the outside atmosphere during any shutdown operation. ...

  6. 30 CFR 77.302 - Bypass stacks.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ....302 Bypass stacks. Thermal dryer systems shall include a bypass stack, relief stack or individual discharge stack provided with automatic venting which will permit gases from the dryer heating unit to bypass the heating chamber and vent to the outside atmosphere during any shutdown operation. ...

  7. One Fish Two Fish.

    ERIC Educational Resources Information Center

    Hoffman, Michele

    1998-01-01

    This activity explains fisheries resource management to seven-year olds. First-grade students learn concepts such as offspring viability, life expectancy, and distribution of species, which help to determine when, where, and how people fish and the importance of fishing responsibly. Lists materials, procedures, and extensions. (SJR)

  8. One Fish Two Fish.

    ERIC Educational Resources Information Center

    Hoffman, Michele

    1998-01-01

    This activity explains fisheries resource management to seven-year olds. First-grade students learn concepts such as offspring viability, life expectancy, and distribution of species, which help to determine when, where, and how people fish and the importance of fishing responsibly. Lists materials, procedures, and extensions. (SJR)

  9. Interventions in Infrainguinal Bypass Grafts

    SciTech Connect

    Mueller-Huelsbeck, S. Order, B.-M.; Jahnke, T.

    2006-02-15

    The interventional radiologist plays an important role in the detection and prevention of infrainguinal bypass failure. Early detection and evaluation of flow-limiting lesions effectively preserve graft (venous bypass and polyester or expanded polytetrafluoroethylene bypass) patency by identifying stenoses before occlusion occurs. Delay in treatment of the at-risk graft may result in graft failure and a reduced chance of successful revascularization. For this reason, surveillance protocols form an important part of follow-up after infrainguinal bypass surgery. As well as having an understanding of the application of imaging techniques including ultrasound, MR angiography, CT angiography and digital subtraction angiography, the interventional radiologist should have detailed knowledge of the minimally invasive therapeutic options. Percutaneous transluminal angioplasty (PTA), or alternatively cutting balloon angioplasty, is the interventional treatment of choice in prevention of graft failure and occlusion. Further alternatives include metallic stent placement, fibrinolysis, and mechanical thrombectomy. Primary assisted patency rates following PTA can be up to 65% at 5 years. When the endovascular approach is unsuccessful, these therapeutic options are complemented by surgical procedures including vein patch revision, jump grafting, or placement of a new graft.

  10. Heart bypass surgery - minimally invasive

    MedlinePlus

    ... MIDCAB; Robot-assisted coronary artery bypass; RACAB; Keyhole heart surgery; CAD - MIDCAB; Coronary artery disease - MIDCAB ... To perform this surgery: The heart surgeon will make a 3- to 5-inch (8 to 13 centimeters) surgical cut in the left part of your chest ...

  11. Radiation direction control by optical slot antenna integrated with plasmonic waveguide

    NASA Astrophysics Data System (ADS)

    Park, Yeonsang; Kim, Jineun; Roh, Young-Geun; Lee, Chang-Won

    2016-04-01

    We present an optical slot antenna integrated with a metal-dielectric-metal (MIM) plasmonic waveguide. By integrating optical slot antenna on top metal layer of MIM waveguide, we can couple the plasmon guide mode into the feed antenna directly. The resonantly excited slot antenna works as a magnetic dipole and then radiates in dipole-like far-field pattern. By adding an auxiliary groove structure along with the slot antenna, the radiation can be directed into the direction where the structure determined. The demonstrated optical slot antenna integrated with a plasmonic waveguide can be used as a "plasmonic via" in plasmonic nanocircuits.

  12. Computer simulation of a wind tunnel test section with discrete finite-length wall slots

    NASA Technical Reports Server (NTRS)

    Kemp, W. B., Jr.

    1986-01-01

    A computer simulation of a slotted wind tunnel test section which includes a discrete, finite-length wall slot representation with plenum chamber constraints and accounts for the nonlinear effects of the dynamic pressure of the slot outflow jet and of the low energy of slot inflow air was developed. The simulation features were selected to be those appropriate for the intended subsequent use of the simulation in a wall interference assessment procedure using sparsely located wall pressure measurements. It is demonstrated that accounting for slot discreteness is important in interpreting wall pressure measured between slots, and that accounting for nonlinear slot flow effects produces significant changes in tunnel-induced velocity distributions and, in particular, produces a longitudinal component of tunnel-induced velocity due to model lift. A characteristic mode of tunnel flow interaction with constraints imposed by the plenum chamber and diffuser entrance is apparent in simulation results and is derived analytically through a simplified analysis.

  13. Dual frequency, dual polarized, multi-layered microstrip slot and dipole array antenna

    NASA Technical Reports Server (NTRS)

    Tulintseff, Ann N. (Inventor)

    1995-01-01

    An antenna array system is disclosed which uses subarrays of slots and subarrays of dipoles on separate planes. The slots and dipoles respectively are interleaved, which is to say there is minimal overlap between them. Each subarray includes a microstrip transmission line and a plurality of elements extending perpendicular thereto. The dipoles form the transmission elements and the slots form the receive elements. The plane in which the slots are formed also forms a ground plane for the dipoles--hence the feed to the dipole is on the opposite side of this ground plane as the feed to the slots. HPAs are located adjacent the dipoles on one side of the substrate and LNAs are located adjacent the slots on the other side of the substrate. The dipoles and slots are tuned by setting different offsets between each element and the microstrip transmission line.

  14. The Role of Auditory Features Within Slot-Themed Social Casino Games and Online Slot Machine Games.

    PubMed

    Bramley, Stephanie; Gainsbury, Sally M

    2015-12-01

    Over the last few years playing social casino games has become a popular entertainment activity. Social casino games are offered via social media platforms and mobile apps and resemble gambling activities. However, social casino games are not classified as gambling as they can be played for free, outcomes may not be determined by chance, and players receive no monetary payouts. Social casino games appear to be somewhat similar to online gambling activities in terms of their visual and auditory features, but to date little research has investigated the cross over between these games. This study examines the auditory features of slot-themed social casino games and online slot machine games using a case study design. An example of each game type was played on three separate occasions during which, the auditory features (i.e., music, speech, sound effects, and the absence of sound) within the games were logged. The online slot-themed game was played in demo mode. This is the first study to provide a qualitative account of the role of auditory features within a slot-themed social casino game and an online slot machine game. Our results found many similarities between how sound is utilised within the two games. Therefore the sounds within these games may serve functions including: setting the scene for gaming, creating an image, demarcating space, interacting with visual features, prompting players to act, communicating achievements to players, providing reinforcement, heightening player emotions and the gaming experience. As a result this may reduce the ability of players to make a clear distinction between these two activities, which may facilitate migration between games.

  15. Theory of a Traveling Wave Feed for a Planar Slot Array Antenna

    NASA Technical Reports Server (NTRS)

    Rengarajan, Sembiam

    2012-01-01

    Planar arrays of waveguide-fed slots have been employed in many radar and remote sensing applications. Such arrays are designed in the standing wave configuration because of high efficiency. Traveling wave arrays can produce greater bandwidth at the expense of efficiency due to power loss in the load or loads. Traveling wave planar slot arrays may be designed with a long feed waveguide consisting of centered-inclined coupling slots. The feed waveguide is terminated in a matched load, and the element spacing in the feed waveguide is chosen to produce a beam squinted from the broadside. The traveling wave planar slot array consists of a long feed waveguide containing resonant-centered inclined coupling slots in the broad wall, coupling power into an array of stacked radiating waveguides orthogonal to it. The radiating waveguides consist of longitudinal offset radiating slots in a standing wave configuration. For the traveling wave feed of a planar slot array, one has to design the tilt angle and length of each coupling slot such that the amplitude and phase of excitation of each radiating waveguide are close to the desired values. The coupling slot spacing is chosen for an appropriate beam squint. Scattering matrix parameters of resonant coupling slots are used in the design process to produce appropriate excitations of radiating waveguides with constraints placed only on amplitudes. Since the radiating slots in each radiating waveguide are designed to produce a certain total admittance, the scattering (S) matrix of each coupling slot is reduced to a 2x2 matrix. Elements of each 2x2 S-matrix and the amount of coupling into the corresponding radiating waveguide are expressed in terms of the element S11. S matrices are converted into transmission (T) matrices, and the T matrices are multiplied to cascade the coupling slots and waveguide sections, starting from the load end and proceeding towards the source. While the use of non-resonant coupling slots may provide an

  16. Mini cardiopulmonary bypass: Anesthetic considerations

    PubMed Central

    Alsatli, Raed A.

    2012-01-01

    This review article is going to elaborate on the description, components, and advantages of mini-cardiopulmonary bypass (mini-CPB), with special reference to the anesthetic management and fast track anesthesia with mini-CPB. There are several clinical advantages of mini-CPB like, reduced inflammatory reaction to the pump, reduced need for allogenic blood transfusion and lower incidence of postoperative neurological complications. There are certainly important points that have to be considered by anesthesiologists to avoid sever perturbation in the cardiac output and blood pressure during mini-CPB. Fast-track anesthesia provides advantages regarding fast postoperative recovery from anesthesia, and reduction of postoperative ventilation time. Mini bypass offers a sound alternative to conventional CPB, and has definite advantages. It has its limitations, but even with that it has a definite place in the current practice of cardiac surgery. PMID:25885494

  17. The effect of embedded bonus rounds on slot machine preference.

    PubMed

    Belisle, Jordan; Owens, Kelti; Dixon, Mark R; Malkin, Albert; Jordan, Sam D

    2017-04-01

    Twenty-three university students completed a simulated slot machine task involving the concurrent presentation of two slot machines that were varied both in win density and the inclusion of a bonus round feature to evaluate the effect of embedded bonus rounds on participant response allocation. The results suggest that participants allocated a greater percentage of responses to machines with embedded bonus rounds across both dense (Bonus: M = 68.4, SD = 19.2; No Bonus: M = 51.2; 9.6) and lean (Bonus: M = 48.8, SD = 9.6; No Bonus: M = 31.6, SD = 19.2) reinforcement schedules, in which the overall reinforcement rate across all machines was held constant.

  18. X-band slotted array test panel and test fixture

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Data from the development of the X-band slotted array test band, X-band array test fixture, and the X/L-band test fixture for the Support Instrumentation Requirements program are documented. An X-band array was built and installed with an existing L-band module in such a way as to permit antenna pattern measurements in a series of nonplanar configurations that might simulate the thermal effects of nonuniform solar illumination on the array in a space environment. This was accomplished with eight X-band subpanels mounted adjacently on individually adjusted supports which were then co-mounted to a larger frame which served to mount and physically distort the existing L-band module. The L-band module is a heavy electrical breadboard array section that was fabricated to demonstrate the performance capabilities of a slotted waveguide array at L-band frequencies. Drawings, mechanical analysis, and descriptions of test configurations are presented.

  19. Slotted photonic crystal cavities with integrated microfluidics for biosensing applications.

    PubMed

    Scullion, M G; Di Falco, A; Krauss, T F

    2011-09-15

    We demonstrate the detection of dissolved avidin concentrations as low as 15 nM or 1 μg/ml using functionalized slotted photonic crystal cavities with integrated microfluidics. With a cavity sensing surface area of approximately 2.2 μm(2), we are able to detect surface mass densities of order 60 pg/mm(2) corresponding to a bound mass of approximately 100 ag. The ultra-compact size of the sensors makes them attractive for lab-on-a-chip applications where high densities of independent sensing elements are desired within a small area. The high sensitivity over an extremely small area is due to the strong modal overlap with the analyte enabled by the slotted waveguide cavity geometry that we employ. This strong overlap results in larger shifts in the cavity peak wavelength when compared to competing approaches.

  20. Radiation properties of slot and dipole elements on layered substrates

    NASA Astrophysics Data System (ADS)

    Rogers, R. L.; Neikirk, D. P.

    1989-06-01

    Calculation results are presented for the radiation properties of slot and dipole antennas on electrically thick grounded dielectric substrates, with application to the development of mm-wave and far-IR imaging arrays. Factors considered in the selection of dieletric layers include the beam patterns, surface waves losses, and the type of element used. The effects of dielectric and ground plane losses are taken into account for the case of high-gain structures. Results for the efficiencies and beam patterns of three and five layer structures show that, in combination with a twin element configuration, both slot and dipole antennas can overcome the problem of losses to surface waves in the substrate and be made to efficiently radiate to air on these layered dielectric structures.

  1. Induction forming of metal components with slotted susceptors

    DOEpatents

    Matsen, Marc R; Dykstra, William

    2013-02-19

    A laminated tooling apparatus includes a first tooling die, a first susceptor carried by the first tooling die and having at least one straight susceptor portion and at least one angled susceptor portion adjacent to the straight susceptor portion, a first plurality of susceptor slots extending through the at least one angled susceptor portion of the first tooling die, a second tooling die adjacent to the first tooling die, a second susceptor carried by the second tooling die and having at least one straight susceptor portion and at least one angled susceptor portion adjacent to the straight susceptor portion; and a second plurality of susceptor slots extending through the at least one angled susceptor portion of the second tooling die.

  2. Calculation of turbulent boundary layers with tangential slot injection

    NASA Technical Reports Server (NTRS)

    Cary, A. M., Jr.; Bushnell, D. M.; Hefner, J. N.

    1977-01-01

    Paper describes a numerical calculation scheme for tangential slot injection (wall-wake) flows; application of the scheme over a wide range of flow conditions indicates increased accuracy compared to previous work. Predictions from the numerical code were in good agreement with experiment (velocity profile, skin-friction, and effectiveness data) for low- and high-speed flows. To achieve improved accuracy, modifications in the turbulence modeling, compared to previous research, were necessary for the imbedded shear layer region in the near field and for the wall region near shear layer impingement. Anomalous behavior was noted for far field experimental velocity profiles in low-speed flow when the slot-to-free stream velocity ratio was near one

  3. Evaluation of detectable angle of mid-infrared slot antennas

    NASA Astrophysics Data System (ADS)

    Obara, R.; Horikawa, J.; Shimakage, H.; Kawakami, A.

    2017-07-01

    For evaluations of a mid-infrared (MIR) detectors with antenna, we constructed an angular dependence measurement system of the antenna properties. The fabricated MIR detector consisted of twin slot antennas and a bolometer. The area of the slot antennas was designed to be 2.6 × 0.2 μm2 as to resonate at 61 THz, and they were located parallel and separated 1.6 μm each other. The bolometer was fabricated using by a 7.0-nm thick NbN thin film, and located at the center of the twin antennas. We measured polarization angle dependence and directivity, and showed that the MIR antennas have polarization dependence and directivity like radiofrequency antennas.

  4. Loop-mirror-based slot waveguide refractive index sensor

    NASA Astrophysics Data System (ADS)

    Kou, Jun-long; Xu, Fei; Lu, Yan-qing

    2012-12-01

    Loop mirror has been widely used in fiber optical devices and systems for it provides a smart way to make use of the fiber birefringence properties and can enhance the sensitivity greatly. On the other hand, slot waveguide is very promising for optical sensing applications because of their peculiar spatial mode profile. In this paper, we propose and analyze a loop-mirror-based slot waveguide (LMSW) sensor which can be routinely fabricated in modern high-volume complementary metal-oxide-semiconductor (CMOS) process. The finite element method (FEM) simulation results show that the birefringence can be as high as 0.8 which is orders of magnitude than that in conventional birefringent fiber loop mirror. High sensitivity up to 6 × 103 nm/RIU (refractive index unit) is achieved by this scheme.

  5. Transmission and Incidence Losses for a Slotted Plate

    NASA Technical Reports Server (NTRS)

    Wilson, Jack; Chima, Rodrick V.; Skews, Beric W.

    1998-01-01

    The objective of this work is to find a model of the stagnation pressure loss resulting from flow through a slotted plate, which is effectively a cascade of flat plate airfoils, particularly at very large angles of incidence. Data from a published experiment is examined, and compared with control volume analysis, and CFD code calculations. An assumption that the loss can be separated into a transmission loss and an incidence loss seems to be justified by the data. Both the data and the CFD code results are consistent with an incidence loss model in which the flow component normal to the slot axis is lost. However, the experimental transmission loss is much larger than calculated values.

  6. Slot-line end-fire antennas for THz frequencies

    NASA Technical Reports Server (NTRS)

    Ekstroem, H.; Gearhart, S.; Acharya, P. R.; Dave, H.; Rebeiz, G.; Jacobsson, S.; Kollberg, E.; Chin, G.

    1992-01-01

    Tapered slot-line endfire antennas, of BLTSA type, have been fabricated on 1.7 micron thin SiO2/Si3N4 (epsilon (sub r) = 4.5) dielectric membranes. The antenna patterns, in the E-, H-, D- and D-cross planes, were measured at 270, 348, 370, and 802 GHz using bismuth micro bolometer detectors. The antennas have approximately 12 dB directivity, and the -10 dB beam widths are 50 and 55 degrees in the E- and H-planes at 348 GHz, respectively. The measurements at millimeter/submillimeter wavelengths compare well with scale measurements at 45 GHz as well as with theoretical predictions. The overall results are encouraging and show that slot-line antennas can be fabricated for use at THz frequencies. Furthermore, it is shown that the very thin SiO2/Si3N4 membranes are strong enough to be used in practical applications.

  7. Microwave beamed power technology improvement. [magnetrons and slotted waveguide arrays

    NASA Technical Reports Server (NTRS)

    Brown, W. C.

    1980-01-01

    The magnetron directional amplifier was tested for (1) phase shift and power output as a function of gain, anode current, and anode voltage, (2) background noise and harmonics in the output, (3) long life potential of the magnetron cathode, and (4) high operational efficiency. Examples of results were an adequate range of current and voltage over which 20 dB of amplification could be obtained, spectral noise density 155 dB below the carrier, 81.7% overall efficiency, and potential cathode life of 50 years in a design for solar power satellite use. A fabrication method was used to fabricate a 64 slot, 30 in square slotted waveguide array module from 0.020 in thick aluminum sheet. The test results on the array are discussed.

  8. Pulsar Polar Cap and Slot Gap Models: Confronting Fermi Data

    NASA Technical Reports Server (NTRS)

    Harding, Alice K.

    2012-01-01

    Rotation-powered pulsars are excellent laboratories for studying particle acceleration as well as fundamental physics of strong gravity, strong magnetic fields and relativity. I will review acceleration and gamma-ray emission from the pulsar polar cap and slot gap. Predictions of these models can be tested with the data set on pulsars collected by the Large Area Telescope on the Fermi Gamma-Ray Telescope over the last four years, using both detailed light curve fitting and population synthesis.

  9. Multiaccess of a Slotted Channel by Finitely Many Users,

    DTIC Science & Technology

    1981-08-01

    sequential decision making formulation of the multi- attention during the past decade is that of organiz- access problem. In Section 6 we define the...arrivals and transmission decicions B - Etnumber of blocked packet arrivals per slot] (local information). Moreover, considering the Pa Pr[successful packet...decision the time the packet enters a buffer until making in an environment of decentralized decisionthe end of its successful transmission makers with

  10. A new integrated slot element feed array for multibeam systems

    NASA Technical Reports Server (NTRS)

    Yngvesson, K. Sigfrid; Johansson, Joakim F.; Kollberg, Erik L.

    1986-01-01

    A feed array consisting of constant width slot antennas (CWSA), fed from a block containing fin-line transitions, has been developed. The array has a two-dimensional configuration, with five elements each on five parallel substrates. Beamwidths are compatible with use in f/D = 1.0 multibeam systems, with optimum taper. Array element spacings are close to a factor of two smaller than for other typical arrays, and spillover efficiency is about 65 percent.

  11. A multi-slot surface coil for MRI of dual-rat imaging at 4 T

    NASA Astrophysics Data System (ADS)

    Solis, S. E.; Wang, R.; Tomasi, D.; Rodriguez, A. O.

    2011-06-01

    A slotted surface coil inspired by the hole-and-slot cavity magnetron was developed for magnetic resonance imaging of obese rats at 4 T. Full-wave analysis of the magnetic field was carried out at 170 MHz for both the slotted and circular-shaped coils. The noise figure values of two coils were investigated via the numerical calculation of the quality factors. Fat simulated phantoms to mimic overweight rats were included in the analysis with weights ranging from 300 to 900 g. The noise figures were 1.2 dB for the slotted coil and 2.4 dB for the circular coil when loaded with 600 g of simulated phantom. A slotted surface coil with eight circular slots and a circular coil with similar dimensions were built and operated in the transceiver mode, and their performances were experimentally compared. The imaging tests in phantoms demonstrated that the slotted surface coil has a deeper RF-sensitivity and better field uniformity than the single-loop RF-coil. High quality images of two overweight Zucker rats were acquired simultaneously with the slotted surface coil using standard spin-echo pulse sequences. Experimental results showed that the slotted surface coil outperformed the circular coil for imaging considerably overweight rats. Thus, the slotted surface coil can be a good tool for MRI experiments in rats on a human whole-body 4 T scanner.

  12. A multi-slot surface coil for MRI of dual-rat imaging at 4T

    SciTech Connect

    Solis, S.E.; Tomasi, D.; Solis, S.E.; Wang, R.; Tomasi, D.; Rodriguez, A.O.

    2011-07-01

    A slotted surface coil inspired by the hole-and-slot cavity magnetron was developed for magnetic resonance imaging of obese rats at 4 T. Full-wave analysis of the magnetic field was carried out at 170 MHz for both the slotted and circular-shaped coils. The noise figure values of two coils were investigated via the numerical calculation of the quality factors. Fat simulated phantoms to mimic overweight rats were included in the analysis with weights ranging from 300 to 900 g. The noise figures were 1.2 dB for the slotted coil and 2.4 dB for the circular coil when loaded with 600 g of simulated phantom. A slotted surface coil with eight circular slots and a circular coil with similar dimensions were built and operated in the transceiver mode, and their performances were experimentally compared. The imaging tests in phantoms demonstrated that the slotted surface coil has a deeper RF-sensitivity and better field uniformity than the single-loop RF-coil. High quality images of two overweight Zucker rats were acquired simultaneously with the slotted surface coil using standard spin-echo pulse sequences. Experimental results showed that the slotted surface coil outperformed the circular coil for imaging considerably overweight rats. Thus, the slotted surface coil can be a good tool for MRI experiments in rats on a human whole-body 4 T scanner.

  13. Experimental GVD engineering in slow light slot photonic crystal waveguides

    PubMed Central

    Serna, Samuel; Colman, Pierre; Zhang, Weiwei; Le Roux, Xavier; Caer, Charles; Vivien, Laurent; Cassan, Eric

    2016-01-01

    The use in silicon photonics of the new optical materials developed in soft matter science (e.g. polymers, liquids) is delicate because their low refractive index weakens the confinement of light and prevents an efficient control of the dispersion properties through the geometry. We experimentally demonstrate that such materials can be incorporated in 700 μm long slot photonic crystal waveguides, and hence can benefit from both slow-light field enhancement effect and slot-induced ultra-small effective areas. Additionally, we show that their dispersion can be engineered from anomalous to normal regions, along with the presence of multiple zero group velocity dispersion (ZGVD) points exhibiting Normalized Delay Bandwidth Product as high as 0.156. The reported results provide experimental evidence for an accurate control of the dispersion properties of fillable periodical slotted structures in silicon photonics, which is of direct interest for on-chip all-optical data treatment using nonlinear optical effects in hybrid-on-silicon technologies. PMID:27243377

  14. Experimental GVD engineering in slow light slot photonic crystal waveguides.

    PubMed

    Serna, Samuel; Colman, Pierre; Zhang, Weiwei; Le Roux, Xavier; Caer, Charles; Vivien, Laurent; Cassan, Eric

    2016-05-31

    The use in silicon photonics of the new optical materials developed in soft matter science (e.g. polymers, liquids) is delicate because their low refractive index weakens the confinement of light and prevents an efficient control of the dispersion properties through the geometry. We experimentally demonstrate that such materials can be incorporated in 700 μm long slot photonic crystal waveguides, and hence can benefit from both slow-light field enhancement effect and slot-induced ultra-small effective areas. Additionally, we show that their dispersion can be engineered from anomalous to normal regions, along with the presence of multiple zero group velocity dispersion (ZGVD) points exhibiting Normalized Delay Bandwidth Product as high as 0.156. The reported results provide experimental evidence for an accurate control of the dispersion properties of fillable periodical slotted structures in silicon photonics, which is of direct interest for on-chip all-optical data treatment using nonlinear optical effects in hybrid-on-silicon technologies.

  15. Analysis of a high power microwave radial line slot antenna.

    PubMed

    Peng, Shengren; Yuan, Chengwei; Shu, Ting

    2013-07-01

    A traditional radial line slot antenna (RLSA) is a high gain planar array. To improve the power handling capacity, we design a radial line slow wave structure which replaces a traditional dielectric sheet in the radial waveguide of the traditional RLSA. This high power microwave (HPM) RLSA is fed from a double-layered radial line waveguide to realize the directional radiation of the microwave. However, the track of the widen slot array on the upper waveguide could cause large reflection, which disturbs the normal antenna operation, accordingly a reflection canceling slot is added to the lower waveguide, the key technology employed in the design of the HPM RLSA and the antenna return-loss is effectively improved. This article mainly gives the design theory of this antenna, which is confirmed by the simulations and experiments. At 9.4 GHz, the calculated aperture efficiency reaches more than 40%, the reflectance is less than 0.1, the radiation efficiency is more than 99% and its measured power-handling capacity exceeds 700 MW.

  16. Applicative Characteristics of a New Zirconia Bracket with Multiple Slots

    PubMed Central

    Maki, Koutaro; Futaki, Katsuyoshi; Tanabe, Satoru; Takahashi, Mariko; Ichikawa, Yuta; Yamaguchi, Tetsutaro

    2016-01-01

    We have developed a new orthodontic bracket with three slots with lubricative properties on the working surfaces and proposed a new orthodontic treatment system employing 0.012−0.014-inch Ni-Ti arch wires. We recruited 54 patients, of which 27 received treatment with the new zirconia bracket with multiple slots system (M group), and the others received treatment with standard edge-wise appliances (control group [C group]). We compared the (1) tooth movement rate at the early stage of leveling; (2) changes in the dental arch morphology before and after leveling; and (3) pain caused by orthodontic treatment. Student's t-test was used in all assessments. The tooth movement rate in the maxillomandibular dentition was higher in the M group. The basal arch width, anterior length, and the intercanine width in the maxillary dentition were not significantly different in the two groups; however, the intercanine width in the mandibular dentition was higher in the C group. In assessments of treatment-related pain, the visual analogue pain score was 56.0 mm and 22.6 mm in the C and M groups, respectively. A new zirconia bracket with multiple slots system provided better outcomes with respect to tooth movement rate, treatment period, and postoperative pain, thus indicating its effectiveness over conventional orthodontic systems. PMID:27212948

  17. Research on cooling effectiveness in stepped slot film cooling vane

    NASA Astrophysics Data System (ADS)

    Li, Yulong; Wu, Hong; Zhou, Feng; Rong, Chengjun

    2016-06-01

    As one of the most important developments in air cooling technology for hot parts of the aero-engine, film cooling technology has been widely used. Film cooling hole structure exists mainly in areas that have high temperature, uneven cooling effectiveness issues when in actual use. The first stage turbine vanes of the aero-engine consume the largest portion of cooling air, thereby the research on reducing the amount of cooling air has the greatest potential. A new stepped slot film cooling vane with a high cooling effectiveness and a high cooling uniformity was researched initially. Through numerical methods, the affecting factors of the cooling effectiveness of a vane with the stepped slot film cooling structure were researched. This paper focuses on the cooling effectiveness and the pressure loss in different blowing ratio conditions, then the most reasonable and scientific structure parameter can be obtained by analyzing the results. The results show that 1.0 mm is the optimum slot width and 10.0 is the most reasonable blowing ratio. Under this condition, the vane achieved the best cooling result and the highest cooling effectiveness, and also retained a low pressure loss.

  18. Fish Allergy

    MedlinePlus

    ... can react to touching fish or breathing in vapors from cooking fish. A fish allergy can cause ... hives red spots swelling a drop in blood pressure , causing lightheadedness or loss of consciousness Your child ...

  19. City Fishing.

    ERIC Educational Resources Information Center

    Lange, Robert E.

    1979-01-01

    A program of supplying opportunities for fishing at locations within and near urban areas was developed. This effort included stocking, management of bodies of water for fishing, and presentation of fishing clinics for urban fishermen. (RE)

  20. Fish Hearing.

    ERIC Educational Resources Information Center

    Blaxter, J. H. S.

    1980-01-01

    Provides related information about hearing in fish, including the sensory stimulus of sound in the underwater environment, mechanoreceptors in fish, pressure perception and the swimbladder, specializations in sound conduction peculiar to certain fish families. Includes numerous figures. (CS)

  1. Abdominal Pain following Gastric Bypass: Suspects & Solutions

    PubMed Central

    Greenstein, Alexander J.; O’Rourke, Robert W.

    2010-01-01

    Introduction Gastric bypass remains the mainstay of surgical therapy for obesity. Abdominal pain after gastric bypass is common, and accounts for up to half of all postoperative complaints and emergency room visits. This manuscript reviews the most important causes of abdominal pain specific to gastric bypass and discusses management considerations. Data Sources The current surgical literature was reviewed using PubMed, with a focus on abdominal pain after gastric bypass and the known pathologies that underlie its pathogenesis. Conclusions The differential diagnosis for abdominal pain after gastric bypass is large and includes benign and life-threatening entities. Its diverse causes require a broad evaluation that should be directed by history and clinical presentation. In the absence of a clear diagnosis, the threshold for surgical exploration in patients with abdominal pain after gastric bypass should be low. PMID:21333269

  2. Ramjet bypass duct and preburner configuration

    NASA Technical Reports Server (NTRS)

    Orlando, Robert J. (Inventor)

    1994-01-01

    A combined turbofan and ramjet aircraft engine includes a forward bypass duct which allows the engine to operate more efficiently during the turbofan mode of operation. By mounting a ramjet preburner in the forward duct and isolating this duct from the turbofan bypass air, a transition from turbofan operation to ramjet operation can take place at lower flight Mach numbers without incurring pressure losses or blockage in the turbofan bypass air.

  3. Investigation of the three-dimensional turbulent flow downstream of swept slot injection in hypersonic flow

    NASA Technical Reports Server (NTRS)

    Hefner, J. N.; Cary, A. M., Jr.; Bushnell, D. M.

    1974-01-01

    Results of an experimental and numerical investigation of tangential swept slot injection (sweep angles of 22.5 and 45 deg) into a thick turbulent boundary layer at Mach 6 are presented. Film cooling effectiveness, skin friction, and flow structure downstream of the swept slot injection are investigated. The data are compared to that for unswept slots, and it is found that cooling effectiveness and skin-friction reductions are not significantly affected by sweeping the slot. Predictions of cooling effectiveness and skin friction obtained by a numerical finite-difference technique agree reasonably well with experimental surface variables. As in previous supersonic two-dimensional slot research, reduced mixing was found downstream of the slot lip in the present three-dimensional case.

  4. Optimization of Pole and Slot Widths for Reluctance Torque Reduction in a Brushless DC Spindle Motor

    NASA Astrophysics Data System (ADS)

    Chuang, T. Y.; Lieu, D. K.; McAllister, J. S.

    A parametric study was conducted to determine the effect of motor stator slot widths and rotor permanent magnet pole separation widths on the reluctance torque. This study is based on a finite element analysis of a particular 6-pole/9-slot motor. The analysis can be expanded to other slot/pole combinations. Force and torque calculations were based on an integration of the Maxwell stresses along the center of the airgap. As a general rule, the reluctance torque may be reduced by decreasing the slot width for any given pole separation. For any given slot width, the reluctance torque can be reduced to zero by selection of the proper pole separation. The optimum slot widths are slightly different than those predicted by past analytical formulation. There will be, however, a noticeable effect on the main drive torque and the torque ripple.

  5. Spreadsheet Calculation of Jets in Crossflow: Opposed Rows of Slots Slanted at 45 Degrees

    NASA Technical Reports Server (NTRS)

    Holderman, James D.; Clisset, James R.; Moder, Jeffrey P.

    2011-01-01

    The purpose of this study was to extend a baseline empirical model to the case of jets entering the mainstream flow from opposed rows of 45 degrees slanted slots. The results in this report were obtained using a spreadsheet modified from the one posted with NASA/TM--2010-216100. The primary conclusion in this report is that the best mixing configuration for opposed rows of 45 degrees slanted slots at any down stream distance is a parallel staggered configuration where the slots are angled in the same direction on top and bottom walls and one side is shifted by half the orifice spacing. Although distributions from perpendicular slanted slots are similar to those from parallel staggered configurations at some downstream locations, results for perpendicular slots are highly dependent on downstream distance and are no better than parallel staggered slots at locations where they are similar and are worse than parallel ones at other distances.

  6. Scan-independent slot arrays with parasitic wire arrays in stratified medium

    NASA Technical Reports Server (NTRS)

    Ng, Kwong T.; Munk, Benedikt A.

    1988-01-01

    The effect of a parasitic wire array on the scan admittance of a slot array has been investigated. Structures considered can consist of an infinite slot array and an arbitrary number of parasitic infinte arrays of piecewise linear wires, all arrays being embedded in a stratified medium. These include, as particular cases, phased arrays of Clavin elements. Expressing the fields from the arrays as plane waves, a procedure similar to the periodic moment method for infinite periodic structures is set up to obtain the the scan admittance of the slot array. Scan admittances are presented for a slot array with monopole arrays in free space, and a slot array with a tilted dipole array in a stratified medium. Blind spots at which the incident energy is mainly reflected rather than transmitted were found. Results obtained indicate the possibility of using parasitic wire arrays for scan compensation of active slot arrays.

  7. Differential changes in dietary habits after gastric bypass versus gastric banding operations.

    PubMed

    Ernst, Barbara; Thurnheer, Martin; Wilms, Britta; Schultes, Bernd

    2009-03-01

    Reduction of food intake is an important mechanism by which bariatric procedures reduce body weight. However, only few studies have systematically assessed what patients actually eat after different types of bariatric operations. Dietary habits were assessed by a food frequency questionnaire in 121 bariatric patients (48 gastric bypass patients, 73 gastric banding patients) during follow-up visits in our interdisciplinary obesity center as well as in 45 severely obese (body mass index (BMI)>35 kg/m2) and 45 nonobese (BMI<27 kg/m2) control subjects. As compared with nonobese control subjects, obese control subjects consumed more meat, white bread, and diet soft drinks. Gastric bypass patients showed an enhanced consumption of foods rich in protein such as poultry, fish, and eggs as well as of cooked vegetables, while the consumption of fatty sweets like chocolate, cake, biscuits, and cookies was found to be distinctly reduced in this patient group. In contrast, gastric banding patients reported on a reduced intake of pasta, white bread, and fresh fruits and, just like gastric bypass patients, also on an enhanced intake of poultry and fish. Direct comparison of dietary habits between the two bariatric patient groups revealed that gastric bypass patients consumed more frequently fresh fruits, eggs, and diet soft drinks but strikingly less chocolate than gastric banding patients. Collectively, data clearly point to distinct changes in dietary habits after bariatric operations which markedly differ between gastric bypass and gastric banding patients. Overall, it is tempting to conclude that gastric bypass operations lead to a healthier and a more balanced diet than gastric band implantations.

  8. 21 CFR 870.4310 - Cardiopulmonary bypass coronary pressure gauge.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass coronary pressure gauge... Cardiopulmonary bypass coronary pressure gauge. (a) Identification. A cardiopulmonary bypass coronary pressure... the coronary arteries. (b) Classification. Class II (performance standards). ...

  9. Design and Performance Evaluation of Slotted Walls for Two-Dimensional Wind Tunnels

    NASA Technical Reports Server (NTRS)

    Barnwell, R. W.

    1978-01-01

    A procedure for designing slotted walls for two dimensional wind tunnels is is presented. The design objective is the minimization of blockage of streamline curvature or the reduction of both. The slotted wall boundary condition is derived both for flow from the tunnel into the plenum and vice versa, and the procedure for evaluating wall interference is described. A correlation of experimental data for the slotted wall boundary condition is given. Results are given for several designs and evaluations of slotted wind tunnel walls.

  10. Mechanism Design for Multi-slot Ads Auction in Sponsored Search Markets

    NASA Astrophysics Data System (ADS)

    Deng, Xiaotie; Sun, Yang; Yin, Ming; Zhou, Yunhong

    In this paper, we study pricing models for multi-slot advertisements, where advertisers can bid to place links to their sales webpages at one or multiple slots on a webpage, called the multi-slot AD auction problem. We develop and analyze several important mechanisms, including the VCG mechanism for multi-slot ads auction, the optimal social welfare solution, as well as two weighted GSP-like protocols (mixed and hybrid). Furthermore, we consider that forward-looking Nash equilibrium and prove its existence in the weighted GSP-like pricing protocols.

  11. G-Tunnel pressurized slot-testing preparations; Yucca Mountain Site Characterization Project

    SciTech Connect

    Zimmerman, R.M.; Sifre-Soto, C.; Mann, K.L.; Bellman, R.A. Jr.; Luker, S.; Dodds, D.J.

    1992-04-01

    Designers and analysts of radioactive waste repositories must be able to predict the mechanical behavior of the host rock. Sandia National laboratories elected to conduct a development program on pressurized slot testing and featured (1) development of an improved method to cut slots using a chain saw with diamond-tipped cutters, (2) measurements useful for determining in situ stresses normal to slots, (3) measurements applicable for determining the in situ modulus of deformation parallel to a drift surface, and (4) evaluations of the potentials of pressurized slot strength testing. This report describes the preparations leading to the measurements and evaluations.

  12. One-dimensional photonic crystal slot waveguide for silicon-organic hybrid electro-optic modulators

    NASA Astrophysics Data System (ADS)

    Yan, Hai; Xu, Xiaochuan; Chung, Chi-Jui; Subbaraman, Harish; Pan, Zeyu; Chakravarty, Swapnajit; Chen, Ray T.

    2017-02-01

    A one-dimensional (1D) photonic crystal (PC) slot waveguide was proposed and experimentally demonstrated for integrated silicon-organic hybrid modulators. The 1D PC slot waveguide consists of a conventional silicon slot waveguide with periodic rectangular teeth on its two rails. This structure takes advantage of large mode overlap in a conventional slot waveguide and the slow light enhancement from the PC structure. Its simple geometry makes it resistant to fabrication imperfections and helps reduce the propagation loss. The observed effective EO coefficient in an actual Mach-Zehnder interferometer modulator is as high as 490 pm/V owing to slow light effect.

  13. Investigation of transonic flow over segmented slotted wind tunnel wall with mass transfer

    NASA Technical Reports Server (NTRS)

    Bhat, M. K.; Vakili, A. D.; Wu, J. M.

    1990-01-01

    The flowfield on a segmented multi-slotted wind tunnel wall was studied at transonic speeds by measurements in and near the wall layer using five port cone probes. The slotted wall flowfield was observed to be three-dimensional in nature for a relatively significant distance above the slot. The boundary layer characteristics measured on the single slotted wall were found to be very sensitive to the applied suction through the slot. The perturbation in the velocity components generated due to the flow through the slot decay rapidly in the transverse direction. A vortex-like flow existed on the single slotted wall for natural ventilation but diminished with increased suction flow rate. For flow on a segmented multi-slotted wall, the normal velocity component changes were found to be maximum for measurement points located between the segmented slots atop the active chamber. The lateral influence due to applied suction and blowing, through a compartment, exceeded only slightly that in the downstream direction. Limited upstream influence was observed. Influence coefficients were determined from the data in the least-square sense for blowing and suction applied through one and two compartments. This was found to be an adequate determination of the influence coefficients for the range of mass flows considered.

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

    NASA Technical Reports Server (NTRS)

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

    1958-01-01

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

  15. History of cardiopulmonary bypass (CPB).

    PubMed

    Hessel, Eugene A

    2015-06-01

    The development of cardiopulmonary bypass (CPB), thereby permitting open-heart surgery, is one of the most important advances in medicine in the 20th century. Many currently practicing cardiac anesthesiologists, cardiac surgeons, and perfusionists are unaware of how recently it came into use (60 years) and how much the practice of CPB has changed during its short existence. In this paper, the development of CPB and the many changes and progress that has taken place over this brief period of time, making it a remarkably safe endeavor, are reviewed. The many as yet unresolved questions are also identified, which sets the stage for the other papers in this issue of this journal.

  16. Nonlinear optimal control of bypass transition in a boundary layer flow

    NASA Astrophysics Data System (ADS)

    Xiao, Dandan; Papadakis, George

    2017-05-01

    The central aim of the paper is to apply and assess a nonlinear optimal control strategy to suppress bypass transition, due to bimodal interactions [T. A. Zaki and P. A. Durbin, "Mode interaction and the bypass route to transition," J. Fluid Mech. 531, 85 (2005)] in a zero-pressure-gradient boundary layer. To this end, a Lagrange variational formulation is employed that results in a set of adjoint equations. The optimal wall actuation (blowing and suction from a control slot) is found by solving iteratively the nonlinear Navier-Stokes and the adjoint equations in a forward/backward loop using direct numerical simulation. The optimization is performed in a finite time horizon. Large values of optimization horizon result in the instability of the adjoint equations. The control slot is located exactly in the region of transition. The results show that the control is able to significantly reduce the objective function, which is defined as the spatial and temporal integral of the quadratic deviation from the Blasius profile plus a term that quantifies the control cost. The physical mechanism with which the actuation interacts with the flow field is investigated and analysed in relation to the objective function employed. Examination of the joint probability density function shows that the control velocity is correlated with the streamwise velocity in the near wall region but this correlation is reduced as time elapses. The spanwise averaged velocity is distorted by the control action, resulting in a significant reduction of the skin friction coefficient. Results are presented with and without zero-net mass flow constraint of the actuation velocity. The skin friction coefficient drops below the laminar value if there is no mass constraint; it remains however larger than laminar when this constraint is imposed. Results are also compared with uniform blowing using the same time-average velocity obtained from the nonlinear optimal algorithm.

  17. Frequency response of slot coating flow to gap disturbances

    NASA Astrophysics Data System (ADS)

    Lee, Semi; Nam, Jaewook

    2016-03-01

    Slot coating is a common method of manufacturing films such as optical films, adhesive tapes, etc. It is a pre-metered method: the final wet film thickness is set by the flow rate and the web speed, and independent of other operating parameters and coating liquid properties. Therefore, it is ideal for precise film thickness control. To produce uniform film, the coating flow needs to be steady-state, two-dimensional, and stable. In the slot coating process, however, there are always some small-scale disturbances generated by rotating process units, such as pumps, rolls, etc., and they usually have periodicity. These disturbances cause a non-uniformity of the moving web direction and could spoil the film quality. Therefore, the sensitivity analysis of coating flow under the periodic disturbances is important. Among all disturbances, a change of coating gap, i.e. the distance between the die lip and the moving substrate, is known to the most dangerous disturbance. This type of disturbance is usually called the gap oscillation, and caused by the substrate thickness variations, mechanical vibration of the coating die or roll, and roll run outs. Here, we analyze the effect of fluid properties, operating conditions and die configurations on response of slot coating flow to gap disturbances. In this study, we use Galerkin/finite element method to solve transient Navier-Stokes equation under periodic disturbance. We define the amplification factor as an indicator of film non-uniformity and analyze the effect of different parameters by comparing the factor. In particular, we use Carreau-Yasuda model to describe shear-thinning property of xanthan gum solution and compare with Newtonian fluid.

  18. Hydrodynamic performance of multiple-row slotted breakwaters

    NASA Astrophysics Data System (ADS)

    Elbisy, Moussa S.; Mlybari, Ehab M.; Helal, Medhat M.

    2016-06-01

    This study examines the hydrodynamic performance of multiple-row vertical slotted breakwaters. We developed a mathematical model based on an eigenfunction expansion method and a least squares technique for Stokes second-order waves. The numerical results obtained for limiting cases of double-row and triple-row walls are in good agreement with results of previous studies and experimental results. Comparisons with experimental measurements of the reflection, transmission, and dissipation coefficients ( C R , C T , and C E ) for double-row walls show that the proposed mathematical model adequately reproduces most of the important features. We found that for double-row walls, the C R increases with increasing wave number, kd, and with a decreasing permeable wall part, dm. The C T follows the opposite trend. The C E slowly increases with an increasing kd for lower kd values, reaches a maximum, and then decreases again. In addition, an increasing porosity of dm would significantly decrease the C R , while increasing the C T . At lower values of kd, a decreasing porosity increases the C E , but for high values of kd, a decreasing porosity reduces the C E . The numerical results indicate that, for triple-row walls, the effect of the arrangement of the chamber widths on hydrodynamic characteristics is not significant, except when kd<0.5. Double-row slotted breakwaters may exhibit a good wave-absorbing performance at kd>0.5, where by the horizontal wave force may be smaller than that of a single wall. On the other hand, the difference between double-row and triple-row vertical slotted breakwaters is marginal.

  19. Dark Flow, Depression and Multiline Slot Machine Play.

    PubMed

    Dixon, Mike J; Stange, Madison; Larche, Chanel J; Graydon, Candice; Fugelsang, Jonathan A; Harrigan, Kevin A

    2017-06-06

    Multiline slot machines allow for a unique outcome type referred to as a loss disguised as a win (LDW). An LDW occurs when a player gains credits on a spin, but fewer credits than their original wager (e.g. 15-cent gain on a 20-cent wager). These outcomes alter the gambler's play experience by providing frequent, albeit smaller, credit gains throughout a playing session that are in fact net losses. Despite this negative overall value, research has shown that players physiologically respond to LDWs as if they are wins, not losses. These outcomes also create a "smoother" experience for the player that seems to promote a highly absorbing, flow-like state that we have called "dark flow". Past research has indicated that there may be a relationship between problem gambling status and dark flow, as well as between dark flow, depression, and gambling expectancies. In this study, we sought to further understand these relationships, while examining the influence of LDWs on game preference in the context of single versus multiline slots play. We used a realistic slot machine simulator equipped with a force transducer to measure how hard players pressed the spin button following different outcomes. This measure of arousal showed that LDWs were treated similarly to small wins. Participants overwhelmingly preferred the multiline game and experienced more positive affect while playing it, compared to the single-line game. Problem gambling severity index scores were related to dark flow in both games, but this relationship was stronger for the multiline game. Additionally, depression symptomatology and dark flow were strongly correlated in the multiline game, with significant relationships between depression and gambling expectancy, and gambling expectancy and dark flow ratings also emerging.

  20. Different optical properties in different periodic slot cavity geometrical morphologies

    NASA Astrophysics Data System (ADS)

    Zhou, Jing; Shen, Meng; Du, Lan; Deng, Caisong; Ni, Haibin; Wang, Ming

    2016-09-01

    In this paper, optical properties of two-dimensional periodic annular slot cavity arrays in hexagonal close-packing on a silica substrate are theoretically characterized by finite difference time domain (FDTD) simulation method. By simulating reflectance spectra, electric field distribution, and charge distribution, we confirm that multiple cylindrical surface plasmon resonances can be excited in annular inclined slot cavities by linearly polarized light, in which the four reflectance dips are attributed to Fabry-Perot cavity resonances in the coaxial cavity. A coaxial waveguide mode TE11 will exist in these annular cavities, and the wavelengths of these reflectance dips are effectively tailored by changing the geometrical pattern of slot cavity and the dielectric materials filled in the cavities. These resonant wavelengths are localized in annular cavities with large electric field enhancement and dissipate gradually due to metal loss. The formation of an absorption peak can be explained from the aspect of phase matching conditions. We observed that the proposed structure can be tuned over the broad spectral range of 600-4000 nm by changing the outer and inner radii of the annular gaps, gap surface topography. Meanwhile, different lengths of the cavity may cause the shift of resonance dips. Also, we study the field enhancement at different vertical locations of the slit. In addition, dielectric materials filling in the annular gaps will result in a shift of the resonance wavelengths, which make the annular cavities good candidates for refractive index sensors. The refractive index sensitivity of annular cavities can also be tuned by the geometry size and the media around the cavity. Annular cavities with novel applications can be implied as surface enhanced Raman spectra substrates, refractive index sensors, nano-lasers, and optical trappers. Project supported by the National Natural Science Foundation of China (Grant No. 61178044), the Natural Science Foundation

  1. Ultra High Bypass Integrated System Test

    NASA Image and Video Library

    2015-09-14

    NASA’s Environmentally Responsible Aviation Project, in collaboration with the Federal Aviation Administration (FAA) and Pratt & Whitney, completed testing of an Ultra High Bypass Ratio Turbofan Model in the 9’ x 15’ Low Speed Wind Tunnel at NASA Glenn Research Center. The fan model is representative of the next generation of efficient and quiet Ultra High Bypass Ratio Turbofan Engine designs.

  2. 40 CFR 403.17 - Bypass.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 28 2010-07-01 2010-07-01 true Bypass. 403.17 Section 403.17 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS GENERAL PRE-TREAT-MENT REGULATIONS FOR EXIST-ING AND NEW SOURCES OF POLLUTION § 403.17 Bypass....

  3. 40 CFR 403.17 - Bypass.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) Definitions. (1) Bypass means the intentional diversion of wastestreams from any portion of an Industrial User... applicable Pretreatment Standards or Requirements. An Industrial User may allow any bypass to occur which... paragraphs (c) and (d) of this section. (c) Notice. (1) If an Industrial User knows in advance of the...

  4. 40 CFR 403.17 - Bypass.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 29 2011-07-01 2009-07-01 true Bypass. 403.17 Section 403.17 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS GENERAL PRE-TREAT-MENT REGULATIONS FOR EXIST-ING AND NEW SOURCES OF POLLUTION § 403.17 Bypass....

  5. 40 CFR 403.17 - Bypass.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... bypass, such as the use of auxiliary treatment facilities, retention of untreated wastes, or maintenance... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS GENERAL PRETREATMENT REGULATIONS FOR EXISTING AND NEW SOURCES OF POLLUTION § 403.17 Bypass. (a...

  6. 40 CFR 403.17 - Bypass.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... bypass, such as the use of auxiliary treatment facilities, retention of untreated wastes, or maintenance... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS GENERAL PRETREATMENT REGULATIONS FOR EXISTING AND NEW SOURCES OF POLLUTION § 403.17 Bypass. (a...

  7. Tricritical spiral vortex instability in cross-slot flow

    NASA Astrophysics Data System (ADS)

    Haward, Simon J.; Poole, Robert J.; Alves, Manuel A.; Oliveira, Paulo J.; Goldenfeld, Nigel; Shen, Amy Q.

    2016-03-01

    We examine fluid flow through cross-slot devices with various depth to width ratios α . At low Reynolds number, Re, flow is symmetric and a sharp boundary exists between the two incoming fluid streams. Above an α -dependent critical value, R ec(α ) , a steady symmetry-breaking bifurcation occurs and a spiral vortex structure develops. Order parameters characterizing the instability grow according to a sixth-order Landau potential, and show a progression from second- to first-order transitions as α increases beyond a tricritical value of α ≈0.55 . Flow simulations indicate the instability is driven by vortex stretching at the stagnation point.

  8. Tricritical spiral vortex instability in cross-slot flow.

    PubMed

    Haward, Simon J; Poole, Robert J; Alves, Manuel A; Oliveira, Paulo J; Goldenfeld, Nigel; Shen, Amy Q

    2016-03-01

    We examine fluid flow through cross-slot devices with various depth to width ratios α. At low Reynolds number, Re, flow is symmetric and a sharp boundary exists between the two incoming fluid streams. Above an α-dependent critical value, Re(c)(α), a steady symmetry-breaking bifurcation occurs and a spiral vortex structure develops. Order parameters characterizing the instability grow according to a sixth-order Landau potential, and show a progression from second- to first-order transitions as α increases beyond a tricritical value of α ≈ 0.55. Flow simulations indicate the instability is driven by vortex stretching at the stagnation point.

  9. Broadband vertical interconnects using slot-coupled shielded microstrip lines

    NASA Technical Reports Server (NTRS)

    Vandenberg, Norman L.; Katehi, Linda P. B.

    1992-01-01

    A full-wave space-domain integral equation analysis of aperture coupled shielded microstrip lines is presented based on the Equivalence Principle. The formulation includes the capability to model multilayered substrates through the derivation of the associated dyadic Green's functions which represent the layers through impedance boundary conditions. The method of moments is used to solve for the line currents and slot voltage with even and odd mode excitations which are then interpreted through transmission line analysis to determine the two-port scattering parameters. A parametric study together with experimental data is presented which demonstrates the behavior of the coupler and the accuracy of the technique.

  10. Quantum walk classical simulation with slot waveguide array for sensing

    NASA Astrophysics Data System (ADS)

    Ma, Qingyan; Wang, Yufei; Qi, Fan; Liu, Zhishuang; Zheng, Wanhua

    2017-10-01

    A quantum walk (QW) classical simulation with a slot waveguide array is first proposed for sensing. The waveguide array is designed on a silicon-on-insulator, with the electric field mainly confined in the cladding region to enhance the interaction between the light and medium. The intensity distribution, i.e. the possibilities of QW, at the end of the array changes with the refractive index of the sensing area (surrounding region). Simulation results show good sensing characteristics with compact footprint and refractive index resolution of 1E-11 RIU.

  11. Space Power Amplification with Active Linearly Tapered Slot Antenna Array

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.; Lee, Richard Q.

    1993-01-01

    A space power amplifier composed of active linearly tapered slot antennas (LTSA's) has been demonstrated and shown to have a gain of 30 dB at 20 GHz. In each of the antenna elements, a GaAs monolithic microwave integrated circuit (MMIC) three-stage power amplifier is integrated with two LTSA's. The LTSA and the MMIC power amplifier has a gain of 11 dB and power added efficiency of 14 percent respectively. The design is suitable for constructing a large array using monolithic integration techniques.

  12. A 20 GHz circularly polarized, fan beam slot array antenna

    NASA Astrophysics Data System (ADS)

    Weikle, D. C.

    1982-03-01

    An EHF waveguide slot array was developed for possible use as a receive-only paging antenna for ground mobile terminals. The design, fabrication, and measured performance of this antenna are presented. The antenna generates a circularly polarized fan beam that is narrow in azimuth and broad in elevation. When mechanically rotated in azimuth, it can receive a 20 GHz satellite transmission independent of mobile terminal direction. Azimuth plane sidelobe levels, which are typically <-40 dB from the main lobe, provide for discrimination against ground and airborne jammers.

  13. Spatial frequency multiplier with active linearly tapered slot antenna array

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.; Lee, Richard Q.

    1994-01-01

    A frequency multiplier with active linearly tapered slot antennas (LTSA's) has been demonstrated at the second harmonic frequency. In each antenna element, a GaAs monolithic microwave integrated circuit (MMIC) distributed amplifier is integrated with two LTSA's. The multiplier has a very wide bandwidth and large dynamic range. The fundamental-to-second harmonic conversion efficiency is 8.1 percent. The spatially combined second harmonic signal is 50 dB above the noise level. The design is suitable for constructing a large array using monolithic integration techniques.

  14. Model Experiments with Slot Antenna Arrays for Imaging

    NASA Technical Reports Server (NTRS)

    Johansson, J. F.; Yngvesson, K. S.; Kollberg, E. L.

    1985-01-01

    A prototype imaging system at 31 GHz was developed, which employs a two-dimensional (5x5) array of tapered slot antennas, and integrated detector or mixer elements, in the focal plane of a prime-focus paraboloid reflector, with an f/D=1. The system can be scaled to shorter millimeter waves and submillimeter waves. The array spacing corresponds to a beam spacing of approximately one Rayleigh distance and a two-point resolution experiment showed that two point-sources at the Rayleigh distance are well resolved.

  15. Characterization of tapered slot antenna feeds and feed arrays

    NASA Technical Reports Server (NTRS)

    Kim, Young-Sik; Yngvesson, K. Sigfrid

    1990-01-01

    A class of feed antennas and feed antenna arrays used in the focal plane of paraboloid reflectors and exhibiting higher than normal levels of cross-polarized radiation in the diagonal planes is addressed. A model which allows prediction of element gain and aperture efficiency of the feed/reflector system is presented. The predictions are in good agreement with experimental results. Tapered slot antenna (TSA) elements are used an example of an element of this type. It is shown that TSA arrays used in multibeam systems with small beam spacings are competitive in terms of aperture efficiency with other, more standard types of arrays incorporating waveguide type elements.

  16. Formation of slot-shaped borehole breakout within weakly cementedsandstones

    SciTech Connect

    Nakagawa, Seiji; Tomutsa, Liviu; Myer, Larry R.

    2005-06-10

    Breakout (wall failure) of boreholes within the earth can take several forms depending upon physical properties of the surrounding rock and the stress and flow conditions. Three distinctive modes of breakout are (I) extensile breakout observed in brittle rocks (e.g., Haimson and Herrick, 1986), (II) shear breakout in soft and clastic rocks (Zoback et al., 1985), and (III) fracture-like, slot-shaped breakout within highly porous granular rocks (Bessinger et al., 1997; Haimson and Song, 1998). During fluid production and injection within weakly cemented high-porosity rocks, the third type of failure could result in sustained and excessive sand production (disintegration of the rock's granular matrix and debris production). An objective of this research is to investigate the physical conditions that result in the formation of slot-shaped borehole breakout, via laboratory experiments. Our laboratory borehole breakout experiment was conducted using synthetic high-porosity sandstone with controlled porosity and strength. Block samples containing a single through-goring borehole were subjected to anisotropic stresses within a specially designed tri-axial loading cell. A series of studies was conducted to examine the impact of (1) stress anisotropy around the borehole, (2) rock strength, and (3) fluid flow rate within the borehole on the formation of slot-shaped borehole breakout. The geometry of the breakout was determined after the experiment using X-ray CT. As observed in other studies (Hamison and Song, 1998; Nakagawa and Myer, 2001), flow within a borehole plays a critical role in extending the slot-shaped breakout. The results of our experiments indicated that the width of the breakout was narrower for stronger rock, possibly due to higher resistance to erosion, and the orientation of the breakout plane was better defined for a borehole subjected to stronger stress anisotropy. In most cases, the breakout grew rapidly once the borehole wall started to fail. This 'run

  17. Waveguide-excited slot arrays for synthetic array radar applications

    NASA Technical Reports Server (NTRS)

    Bostrom, D. E.; Lewis, D. J.; Rupp, F. C.

    1978-01-01

    The basic design considerations for waveguide slottery arrays are reviewed, with emphasis on those design requirements that are most significant to both airborne and spaceborne synthetic array radar (SAR) systems. As an illustration of both design procedures and performance capability of slotted waveguide planar arrays, an L-band planar array was designed, fabricated, and tested. This array has an aperture approximately one meter wide by two meters high and was designed to be a typical submodule of a larger antenna. Measurements of radiation patterns, gain, and VSWR were recorded and are presented, together with the performance characteristics predicted on the basis of theoretical analysis.

  18. Flow around a slotted circular cylinder at various angles of attack

    NASA Astrophysics Data System (ADS)

    Gao, Dong-Lai; Chen, Wen-Li; Li, Hui; Hu, Hui

    2017-10-01

    We experimentally investigated the flow characteristics around a circular cylinder with a slot at different angles of attack. The experimental campaign was performed in a wind tunnel at the Reynolds number of Re = 2.67 × 104. The cylindrical test model was manufactured with a slot at the slot width S = 0.075 D ( D is the diameter of the cylinder). The angle of attack α was varied from 0° to 90°. In addition to measuring the pressure distributions around the cylinder surface, a digital particle image velocimetry (PIV) system was employed to quantify the wake flow characteristics behind the baseline cylinder (i.e., baseline case of the cylinder without slot) and slotted cylinder at various angles of attack. Measurement results suggested that at low angles of attack, the passive jet flow generated by the slot would work as an effective control scheme to modify the wake flow characteristics and contribute to reducing the drag and suppressing the fluctuating lift. The flip-flop phenomenon was also identified and discussed with the slot at 0° angle of attack. As the angle of attack α became 45°, the effects of the slot were found to be minimal. When the angle of attack α of the slot approached 90°, the self-organized boundary layer suction and blowing were realized. As a result, the flow separations on both sides of the test model were found to be notably delayed, the wake width behind the slotted cylinder was decreased and the vortex formation length was greatly shrunk, in comparison with the baseline case. Instantaneous pressure measurement results revealed that the pressure difference between the two slot ends and the periodically fluctuating pressure distributions would cause the alternative boundary layer suction and blowing at α = 90°.

  19. Evaluation of a prototype surface flow bypass for juvenile salmon and steelhead at the powerhouse of Lower Granite Dam, Snake River, Washington, 1996-2000

    USGS Publications Warehouse

    Johnson, G.E.; Anglea, S.M.; Adams, N.S.; Wik, T.O.

    2005-01-01

    A surface flow bypass takes advantage of the natural surface orientation of most juvenile salmon Oncorhynchus spp. and steelhead O. mykiss by providing a route in the upper water column that downstream migrant fishes can use to pass a hydroelectric dam safely. A prototype structure, called the surface bypass and collector (SBC), was retrofitted on the powerhouse of Lower Granite Dam and was evaluated annually with biotelemetry and hydroacoustic techniques during the 5-year life span of the structure (1996-2000) to determine the entrance configuration that maximized passage efficiency and minimized forebay residence time. The best tested entrance configuration had maximum inflow (99 m 3/s) concentrated in a single surface entrance (5 m wide, 8.5 m deep). We identified five important considerations for future surface flow bypass development in the lower Snake River and elsewhere: (1) an extensive flow net should be formed in the forebay by use of relatively high surface flow bypass discharge (>7% of total project discharge); (2) a gradual increase in water velocity with increasing proximity to the surface flow bypass (ideally, acceleration 3 m/s) to entrain the subject juvenile fishes; (4) the shape and orientation of the surface entrance(s) should be adapted to fit site-specific features; and (5) construction of a forebay wall to increase fish availability to the surface flow bypass should be considered. The efficiency of the SBC was not high enough (maximum of 62% relative to passage at turbine units 4-5) for the SBC to operate as a stand-alone bypass. Anywhere that surface-oriented anadromous fish must negotiate hydroelectric dams, surface flow bypass systems can provide cost-effective use of typically limited water supplies to increase the nonturbine passage, and presumably survival, of downstream migrants. ??Copyright by the American Fisheries Society 2005.

  20. Bypass Surgery in Limb Salvage: Polytetrafluoroethylene Prosthetic Bypass

    PubMed Central

    Naoum, Joseph J.; Arbid, Elias J.

    2012-01-01

    Polytetrafluoroethylene (PTFE) grafts have proven to be an adequate alternative conduit for peripheral bypass operations. Whether or not one uses PTFE depends on several factors: surgeon preference, individual patient circumstances, or when autologous greater saphenous vein is not available or adequate. These conventional grafts have evolved and undergone modification. The intraluminal surface has been coated with carbon or bonded with heparin. The structure of grafts has been modified with the creation of a hood or cuff, with the incorporation of a stent-graft segment for a sutureless anastomosis, or the fusion of PTFE with an outer polyester layer to minimize suture hole bleeding. This evolution intends to limit graft thrombogenicity, ameliorate the formation of intimal hyperplasia, decrease complications, and improve overall graft patency. PMID:23342188

  1. Neuropsychological changes after cardiopulmonary bypass for coronary artery bypass grafting.

    PubMed

    Wimmer-Greinecker, G; Matheis, G; Brieden, M; Dietrich, M; Oremek, G; Westphal, K; Winkelmann, B R; Moritz, A

    1998-08-01

    An alarming incidence (1% to 83%) of neuropsychological dysfunction has been reported after operations using cardiopulmonary bypass (CPB). The present clinical study re-evaluates these complications with current CPB technology in a strictly selected low-risk group of coronary artery bypass (CABG) patients. 76 CABG patients, without history of stroke or internal carotid artery stenosis, were examined before, 5 days after, and 2 months after surgery. A neuropsychological test battery was employed according to the "Statement of Consensus on Assessment of Neurobehavioral Outcomes after Cardiac Surgery". Tests include the Block Design Test (problem-solving strategies, recognition and analysis of forms), the Trail Making Test (cognitive achievement at speed), and the Digit Span Test (short-term memory and memory of figures). Both postoperative test scores were not significantly decreased as compared to preoperative values. In contrast, neuron specific enolase (NSE) and S100 b protein, biochemical markers of cerebral injury, increased markedly during and immediately after surgery (NSE preop.: 7.07 +/- 2.40 ng/ml, 1 h postop.: 13.64 +/- 4.50 ng/ml, p < 0.001; S100 b preop.: 0.04 +/- 0.07 ng/ml, after crossclamp: 0.90 +/- 0.69 ng/ml, p < 0.001). One patient displayed postoperative transitional syndrome, another patient suffered from transitory paresis and hypesthesia of the left arm, which disappeared during hospital stay. Biochemical markers demonstrate significant postoperative cerebral injury during and immediately after CPB. However, CPB for CABG does not lead to marked impairment of neuropsychological scores, and clinically relevant neurological findings were observed in one patient only.

  2. Wind tunnel tests of the GA(W)-2 airfoil with 20% aileron, 25% slotted flap, 30% Fowler flap and 10% slot-lip spoiler

    NASA Technical Reports Server (NTRS)

    Wentz, W. H., Jr.

    1977-01-01

    Two dimensional wind tunnel tests were conducted for the GA(W)-2 airfoil section with: 20% aileron, 25% slotted flap; 30% Fowler flap, and 10% slot-lip spoiler. All tests were conducted at a Reynolds number of 2,200,000 and a Mach Number of 0.13. In addition to force measurements, tuft studies were conducted for the slotted and Fowler flap configurations. Aileron and spoiler hinge moments were obtained by integration of surface pressure measurements. Tests results show that a value of 3.82 was obtained with 30% Fowler flap. Aileron control effectiveness and hinge moments were similar to other airfoils. The slot-lip spoiler provided powerful, positive roll control at all flap settings.

  3. Flow Coefficient Behavior for Boundary Layer Bleed Holes and Slots

    NASA Technical Reports Server (NTRS)

    Willis, B. P.; Davis, D. O.; Hingst, W. R.

    1995-01-01

    An experimental investigation into the flow coefficient behavior for nine boundary layer bleed orifice configurations is reported. This test was conducted for the purposes of exploring boundary layer control through mass flow removal and does not address issues of stability bleed. Parametric data consist of bleed region flow coefficient as a function of Mach number, bleed plenum pressure, and bleed orifice geometry. Seven multiple hole configurations and two single slot configurations were tested over a supersonic Mach number range of 1.3 to 2.5 (nominal). Advantages gained by using multiple holes in a bleed region instead of a single spanwise slot are discussed and the issue of modeling an entire array of bleed orifices based on the performance of a single orifice is addressed. Preconditioning the flow approaching a 90 degree inclined (normal) hole configuration resulted in a significant improvement in the performance of the configuration. The same preconditioning caused only subtle changes in performance for a 20 degree inclined (slanted) configuration.

  4. Control of Pseudo-Shock by Slot Injection

    NASA Astrophysics Data System (ADS)

    Okui, Hidetaka; Hiraki, Hisashi; Park, Myeong-Kwan; Oshima, Shuzo; Yamane, Ryuichiro

    It is well known that the boundary layer separation due to the adverse pressure gradient of the pseudo-shock affects the dynamic feature of the pseudo-shock such as the shape of the first shock, the pressure recovery and the self-induced oscillation. The suppression of the separation is effective to control the interaction between the shock wave and the boundary layer. In this research, the boundary layer control with the slot injection is studied experimentally and numerically. The experiment is carried out in a blow-down supersonic wind tunnel at free stream Mach number of 2.0. The numerical simulation is made with the two-dimensional compressible Navier-Stokes code. In solving the equations, the second-order accurate Harten-Yee's upwind TVD scheme and k-ɛ turbulence model modified for the compressible flow are used. The results show that the separation is appreciably suppressed and the shape of the first shock is changed, resulting the wall pressure fluctuation to be greatly reduced. Furthermore the total pressure loss is decreased with the low slot height.

  5. Revisiting Street Intersections Using Slot-Based Systems.

    PubMed

    Tachet, Remi; Santi, Paolo; Sobolevsky, Stanislav; Reyes-Castro, Luis Ignacio; Frazzoli, Emilio; Helbing, Dirk; Ratti, Carlo

    2016-01-01

    Since their appearance at the end of the 19th century, traffic lights have been the primary mode of granting access to road intersections. Today, this centuries-old technology is challenged by advances in intelligent transportation, which are opening the way to new solutions built upon slot-based systems similar to those commonly used in aerial traffic: what we call Slot-based Intersections (SIs). Despite simulation-based evidence of the potential benefits of SIs, a comprehensive, analytical framework to compare their relative performance with traffic lights is still lacking. Here, we develop such a framework. We approach the problem in a novel way, by generalizing classical queuing theory. Having defined safety conditions, we characterize capacity and delay of SIs. In the 2-road crossing configuration, we provide a capacity-optimal SI management system. For arbitrary intersection configurations, near-optimal solutions are developed. Results theoretically show that transitioning from a traffic light system to SI has the potential of doubling capacity and significantly reducing delays. This suggests a reduction of non-linear dynamics induced by intersection bottlenecks, with positive impact on the road network. Such findings can provide transportation engineers and planners with crucial insights as they prepare to manage the transition towards a more intelligent transportation infrastructure in cities.

  6. Design and property study of micro-slot optics

    NASA Astrophysics Data System (ADS)

    Wang, Yuting; Yi, Futing; Zhang, Tianchong; Liu, Jing; Wang, Bo; Zhou, Yue

    2017-03-01

    LIGA (Lithographie Galvanoformung Abformung) as a very useful technique for fabricating devices with micro-scale structures has been reported to make the micro-pore optics (MPO) for years. Light weight is one of the advantages of MPO, making it an alternative for X-ray focusing lenses used on space telescopes. However, researchers seldom considered using the MPO in visible light region. In this article, we designed a micro-slot optics (MSO) similar to MPO and fabricated it by X-ray LIGA technique. The MSO consists of 159 concentric hollow cylinders of nickel with the slot spacings ranging from 59 to 113 μm and the focusing property of MSO is studied by simulations and experiments. Both the simulation and experiment results indicate that MSO is a useful focusing element. The MSO has one focal point when the point source is on the principal optical axis with the size of the focal point equaling to the size of the point source.

  7. MHD-flow in the slotted channels with conducting walls

    SciTech Connect

    Evtushenko, I.; Kirillov, I.; Reed, C.

    1994-12-31

    The results of the MHD-flow experimental studies performed in the support of the {open_quotes}slotted channel{close_quotes} blanket concept are presented. The test sections were of the rectangular slotted geometry with the aspect ration b/a=10 (the longer side b is parallel to the applied magnetic field). Three test sections had different walls conductivity, two of them had equal conductivity of all four walls and the third one had a thick top wall (simulation of the blanket first wall) while the remaining three walls were made of a thin liner which was electrically insulated from its surrounding strongback ({open_quotes}Laminated{close_quotes} walls). The applied magnetic field in these experiments was from 0.6 to 2 T. The working fluids were In-Ga-Sn and NaK. Comparison of the pressure drop data for each channel with the analytical and numerical solutions showed the necessity to the further development of the theoretical methods, for different channels the difference between theoretical and test data was from 10 to 20%.

  8. Cryogenic performance of slotted brazed Rene 41 honeycomb panels

    NASA Technical Reports Server (NTRS)

    Hepler, A. K.; Swegle, A. R.

    1982-01-01

    Two brazed Rene 41 honeycomb panels that would incorporate a frame element were designed, fabricated and tested. The panels were representative of the lower surface of an advanced space transportation vehicle. The first panel was a two span panel supported by a center frame and on edges parallel to it. The second panel was a two span panel supported by a center frame and on edges parallel to it. The second panel was a three span panel supported on two frames and on edges parallel to the frames. Each panel had its outer skin slotted to reduce the thermal stresses of the panel skins. The first panel was tested under simulated boost conditions that included liquid hydrogen exposure of the frame and inner skin and radiant heat to 478K on the outer skins. The first panel was tested to investigate the effect of thermal stresses in skins and core caused by the panel being restrained by a cold integral frame and to observe the effects of frost formation and possible liquid air development in and around outer skin slots.

  9. Revisiting Street Intersections Using Slot-Based Systems

    PubMed Central

    Tachet, Remi; Santi, Paolo; Sobolevsky, Stanislav; Reyes-Castro, Luis Ignacio; Frazzoli, Emilio; Helbing, Dirk; Ratti, Carlo

    2016-01-01

    Since their appearance at the end of the 19th century, traffic lights have been the primary mode of granting access to road intersections. Today, this centuries-old technology is challenged by advances in intelligent transportation, which are opening the way to new solutions built upon slot-based systems similar to those commonly used in aerial traffic: what we call Slot-based Intersections (SIs). Despite simulation-based evidence of the potential benefits of SIs, a comprehensive, analytical framework to compare their relative performance with traffic lights is still lacking. Here, we develop such a framework. We approach the problem in a novel way, by generalizing classical queuing theory. Having defined safety conditions, we characterize capacity and delay of SIs. In the 2-road crossing configuration, we provide a capacity-optimal SI management system. For arbitrary intersection configurations, near-optimal solutions are developed. Results theoretically show that transitioning from a traffic light system to SI has the potential of doubling capacity and significantly reducing delays. This suggests a reduction of non-linear dynamics induced by intersection bottlenecks, with positive impact on the road network. Such findings can provide transportation engineers and planners with crucial insights as they prepare to manage the transition towards a more intelligent transportation infrastructure in cities. PMID:26982532

  10. Circular Microstrip Antenna with Fractal Slots for Multiband Applications

    NASA Astrophysics Data System (ADS)

    Singh, Sivia Jagtar; Singh, Gurpreet; Bharti, Gurpreet

    2017-05-01

    In this paper, a multiband, fractal, slotted, Circular Microstrip Patch Antenna for GSM, WiMAX, C and X bands (satellite communication applications) is presented. A cantor set theory is used to make fractal slots for obtaining the desired multiband. The projected antenna is simulated using Ansys HFSS v13.0 software. Simulation test of this antenna has been carried out for a frequency range of 1 GHz-10 GHz and a peak gain of 9.19 dB at a resonance frequency of 1.9 GHz is obtained. The antenna also resonates at 3.7 GHz, 6.06 GHz and 7.9 GHz with gains of 3.04 dB, 5.19 dB and 5.39 dB respectively. Parameters like voltage standing wave ratio, return loss, and gain are used to compare the results of the projected antenna with conventional CMPA's of same dimensions with full and defective grounds. The projected antenna is fabricated on a glass epoxy material and is tested using Vector Network Analyzer. The performance parameters of the antenna are found to in good agreement with each both using simulated and measured data.

  11. Ion-implantation and analysis for doped silicon slot waveguides

    NASA Astrophysics Data System (ADS)

    Deam, L.; Stavrias, N.; Lee, K. K.; McCallum, J. C.

    2012-10-01

    We have utilised ion implantation to fabricate silicon nanocrystal sensitised erbium-doped slot waveguide structures in a Si/SiO2/Si layered configuration and photoluminescence (PL) and Rutherford backscattering spectrometry (RBS) to analyse these structures. Slot waveguide structures in which light is confined to a nanometre-scale low-index region between two high-index regions potentially offer significant advantages for realisation of electrically-pumped Si devices with optical gain and possibly quantum optical devices. We are currently investigating an alternative pathway in which high quality thermal oxides are grown on silicon and ion implantation is used to introduce the Er and Si-ncs into the SiO2 layer. This approach provides considerable control over the Er and Si-nc concentrations and depth profiles which is important for exploring the available parameter space and developing optimised structures. RBS is well-suited to compositional analysis of these layered structures. To improve the depth sensitivity we have used a 1 MeV α beam and results indicate that a layered silicon-Er:SiO2/silicon structure has been fabricated as desired. In this paper structural results will be compared to Er photoluminescence profiles for samples processed under a range of conditions.

  12. 14 CFR 93.226 - Allocation of slots in low-demand periods.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Allocation of slots in low-demand periods... TRANSPORTATION (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Allocation of... available less than 5 days per week. (2) Any time period for which a slot is available for less than a...

  13. 14 CFR 93.219 - Allocation of slots for essential air service operations and applicable limitations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Allocation of slots for essential air service operations and applicable limitations. 93.219 Section 93.219 Aeronautics and Space FEDERAL... Airports § 93.219 Allocation of slots for essential air service operations and applicable limitations...

  14. Systematic two-dimensional cascade tests. Volume 3: Slotted double circular-arc hydrofoils

    NASA Technical Reports Server (NTRS)

    Columbo, R. M.; Murrin, T. A.

    1972-01-01

    Performance parameters are presented for cascades of slotted double circular-arc hydrofoils tested over a range of systematically introduced variables in a rectilinear cascade tunnel which uses water as the test medium. Cascade configurations included various combinations of an inlet flow angle of 50, 60 and 70 deg; a cascade solidity of 0.75, 1.00 and 1.50; a hydrofoil camber angle of 20, 30, 40 and 45 deg; and angles of incidence between positive and negative stall. The slot was positioned at the 45 percent chord station and the slot exit width was 0.047-in. Tests were also performed with the slot positioned at the 35 percent chord station and with slot widths of 0.63 and 0.094-in. These data were correlated to indicate the effects of slot location and slot width on minimum loss incidence and deviation angles. In addition, a comparison is presented of the performance parameters for cascades of slotted and unslotted hydrofoils.

  15. 14 CFR 93.218 - Slots for transborder service to and from Canada.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... TRANSPORTATION (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Allocation of Commuter and Air Carrier IFR Operations at High Density Traffic Airports § 93.218 Slots for transborder...'Hare in the Winter season. (c) Any modification to the slot base by the Government of Canada or the...

  16. 14 CFR 93.218 - Slots for transborder service to and from Canada.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... TRANSPORTATION (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Allocation of Commuter and Air Carrier IFR Operations at High Density Traffic Airports § 93.218 Slots for transborder...'Hare in the Winter season. (c) Any modification to the slot base by the Government of Canada or the...

  17. 14 CFR 93.218 - Slots for transborder service to and from Canada.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... TRANSPORTATION (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Allocation of Commuter and Air Carrier IFR Operations at High Density Traffic Airports § 93.218 Slots for transborder...'Hare in the Winter season. (c) Any modification to the slot base by the Government of Canada or the...

  18. 14 CFR 93.218 - Slots for transborder service to and from Canada.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... TRANSPORTATION (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Allocation of Commuter and Air Carrier IFR Operations at High Density Traffic Airports § 93.218 Slots for transborder...'Hare in the Winter season. (c) Any modification to the slot base by the Government of Canada or the...

  19. Axial laser beam cleaning of tiny particles on narrow slot sidewalls

    NASA Astrophysics Data System (ADS)

    Yue, Liyang; Wang, Zengbo; Guo, Wei; Li, Lin

    2012-09-01

    Laser cleaning is a rapidly developed technique in recent years. However, it is difficult to apply it to a slot structure, because the sidewall cannot absorb enough laser energy. Meanwhile, the focusing lens concentrates the laser beam and energy on a small spot size at the focusing position. The defocused laser beam after the focusing position would disperse and spatially enlarge. In this study, an axial laser beam (excimer laser, 248 nm) is focused at a position that is slightly in front of the slot (silicon), which makes the defocused beam propagate into the slot, and the sidewall is able to absorb the laser energy through its dispersion. The slot structure is constructed through a combination of three silicon wafers (two as sidewalls, and one as the bottom of the slot). In this manner the slot width can be controlled well during the experiment. Using this method, tiny particles (fused silica, diameter 5 µm) adhered on the slot sidewall are successfully cleaned. The cleaning threshold and efficiency for multiple slot widths (3.5-13 mm) and pulse numbers (0-40) are experimentally determined. A multi-physics model is established to understand the experimental phenomena. The electromagnetic-thermal-mechanical processes during laser cleaning are also analysed.

  20. Modification of Slot-Machine Preferences through the Use of a Conditional Discrimination Paradigm

    ERIC Educational Resources Information Center

    Zlomke, Kimberly R.; Dixon, Mark R.

    2006-01-01

    The present experiment investigated the impact of contextually trained discriminations on gambling behavior. Nine recreational slot-machine players were initially exposed to concurrently available computerized slot machines that were each programmed on random-ratio schedules of reinforcement and differed only in color. All participants distributed…

  1. Analysis of tangential slot blowing on F/A-18 isolated forebody

    NASA Technical Reports Server (NTRS)

    Gee, K.; Rizk, Y.; Schiff, L.

    1994-01-01

    Generation of significant side forces and yawing moments on an F/A-18 fuselage through tangential slot blowing is analyzed using computational fluid dynamics. The effects of freestream Mach number, jet exit conditions, jet length, and jet location are studied. The effects of over- and under-blowing on force and moment production are analyzed. Non-time-accurate solutions are obtained to determine the steady-state side forces, yawing moments, and surface pressure distributions generated by tangential slot blowing. Time-accurate solutions are obtained to study the force onset time lag of tangential slot blowing. Comparison with available experimental data from full-scale wind tunnel and sub-scale wind tunnel tests are made. This computational analysis complements the experimental results and provides a detailed understanding of the effects of tangential slot blowing on the flow field about the isolated F/A-18 forebody. Additionally, it extends the slot-blowing database to transonic maneuvering Mach numbers.

  2. Control of Separating Flow Behind a Step by Means of Slotted Ribs

    NASA Astrophysics Data System (ADS)

    D'yachenko, A. Yu.; Zhdanov, V. L.; Smul'skii, Ya. I.; Terekhov, V. I.

    2017-05-01

    One of the promising and simplest methods of passively controlling separating flow behind a backward-facing step with the aid of slotted ribs is considered. The size and number of slots were varied in wide ranges in experiments so that the relative area of the slots amounted to R = Fs/Fr = 0-1. The influence of the longitudinal vortices induced by the teeth in a rib on the distribution of pressure and heat transfer rate in the recirculation region in the case of varying the sizes of slots in a rib, the spacing between them, and the position of the rib relative to the backwardfacing step has been studied. The effectiveness of using slotted ribs for reducing the length and intensity of the region of reverse flow behind the step is shown.

  3. Residual stress measurement by successive extension of a slot: A literature review

    SciTech Connect

    Prime, M.B.

    1997-05-01

    This report reviews the technical literature on techniques that employ successive extension of a slot and the resulting deformations to measure residual stress. Such techniques are known variously in the literature as the compliance or crack compliance method, the successive cracking method, the slotting method, and a fracture mechanics based approach. The report introduces the field and describes the basic aspects of these methods. The report then reviews all literature on the theoretical developments of the method. The theory portion first considers forward method solutions including fracture mechanics, finite element, analytical, and body force methods. Then it examines inverse solutions, including incremental inverses and series expansions. Next, the report reviews all experimental applications of slotting methods. Aspects reviewed include the specimen geometry and material, the details of making the slot, the method used to measure deformation, and the theoretical solutions used to solve for stress. Finally, the report makes a brief qualitative comparison between slotting methods and other residual stress measurement methods.

  4. High field pulsed microwiggler comprising a conductive tube with periodically space slots

    DOEpatents

    Warren, Roger W.

    1992-01-01

    A microwiggler assembly produces large magnetic fields for oscillating ched particle beams, particularly electron beams for free electron laser (FEL) application. A tube of electrically conductive material is formed with radial slots axially spaced at the period of the electron beam. The slots have alternate 180.degree. relationships and are formed to a maximum depth of 0.6 to 0.7 times the tube circumference. An optimum slot depth is selected to eliminate magnetic quadrupole fields within the microwiggler as determined from a conventional pulsed wire technique. Suitable slot configurations include single slits, double slits, triple slits, and elliptical slots. An axial electron beam direction is maintained by experimentally placing end slits adjacent entrance and exit portions of the assembly, where the end slit depth is determined by use of the pulsed wire technique outside the tube.

  5. High field pulsed microwiggler comprising a conductive tube with periodically space slots

    DOEpatents

    Warren, R.W.

    1992-09-01

    A microwiggler assembly produces large magnetic fields for oscillating charged particle beams, particularly electron beams for free electron laser (FEL) application. A tube of electrically conductive material is formed with radial slots axially spaced at the period of the electron beam. The slots have alternate 180[degree] relationships and are formed to a maximum depth of 0.6 to 0.7 times the tube circumference. An optimum slot depth is selected to eliminate magnetic quadrupole fields within the microwiggler as determined from a conventional pulsed wire technique. Suitable slot configurations include single slits, double slits, triple slits, and elliptical slots. An axial electron beam direction is maintained by experimentally placing end slits adjacent entrance and exit portions of the assembly, where the end slit depth is determined by use of the pulsed wire technique outside the tube. 10 figs.

  6. The Aerodynamic Characteristics of a Slotted Clark Y Wing as Affected by the Auxiliary Airfoil Position

    NASA Technical Reports Server (NTRS)

    Wenzinger, Carl J; Shortal, Joseph A

    1932-01-01

    Aerodynamic force tests on a slotted Clark Y wing were conducted in a vertical wind tunnel to determine the best position for a given auxiliary airfoil with respect to the main wing. A systematic series of 100 changes in location of the auxiliary airfoil were made to cover all the probable useful ranges of slot gap, slot width, and slot depth. The results of the investigation may be applied to the design of automatic or controlled slots on wings with geometric characteristics similar to the wing tested. The best positions of the auxiliary airfoil were covered by the range of the tests, and the position for desired aerodynamic characteristics may easily be obtained from charts prepared especially for the purpose.

  7. Application of a Slotted Airfoil for UH-60A Helicopter Performance

    NASA Technical Reports Server (NTRS)

    Yeo, Hyeonsoo; Lim, Joon W.

    2002-01-01

    Recently developed forward slotted airfoils were applied to a UH-60A helicopter, and the performance has been estimated. Baseline SC1095 and SC1094 R8 airfoil characteristics were modified based on CFD calculations of an A3c slotted airfoil to incorporate aerodynamic characteristics of a high-lifting airfoil. The slotted airfoil increases maximum thrust of the UH-60A helicopter by up to 25%, but a significant penalty is observed at CTI9 less than 0.11. This penalty results from higher drag than the baseline airfoil at low angles of attack. A drag reduction at high Mach numbers is necessary to fully exploit the airfoil capability in the rotorcraft application. Preliminary comparison of the slotted airfoil with the wide chord blade shows that the slotted airfoil has limited advantages over the wide chord blade.

  8. Polarization rotator of arbitrary angle based on simple slot-array

    NASA Astrophysics Data System (ADS)

    Liu, Xiaoming; Cao, Xiaohang; Yu, Junsheng; Chen, Xiaodong; Yao, Yuan; Qi, Limei; Chen, Zhijiao; Zhou, Jun

    2015-12-01

    A novel polarization rotator of arbitrary angle was proposed and realized based on simple slot arrays. To achieve the rotation of an arbitrary angle α, the slots on the first layer have to be at an angle of α to the slots on the second layer. Consequently, 90° rotation can be realized using two perpendicularly oriented slot arrays, which overturns the conventional notion of that perpendicular slot arrays are not possible to pass electromagnetic wave. In addition, such structure provides the same bandwidth comparing to its counterpart utilized for frequency selective surface (FSS). Furthermore, such structure is much easier to be fabricated compared to the substrate integrated waveguide (SIW) array. Moreover, low insertion loss can be achieved based on metallic material.

  9. Analysis of Tangential Slot Blowing on F/A-18 Isolated Forebody

    NASA Technical Reports Server (NTRS)

    Gee, Ken; Rizk, Yehia M.; Schiff, Lewis B.

    1995-01-01

    The generation of significant side forces and yawing moments on an F/A-18 fuselage through tangential slot blowing is analyzed using computational fluid dynamics. The effects of freestream Mach number, jet exit conditions, jet length, and jet location are studied. The effects of over- and underblowing on force and moment production are analyzed. Non-time-accurate solutions are obtained to determine the steady-state side forces, yawing moments, and surface pressure distributions generated by tangential slot blowing. Time-accurate solutions are obtained to study the force onset time lag of tangential slot blowing. Comparison with available experimental data from full-scale wind-tunnel and subscale wind-tunnel tests are made. This computational analysis complements the experimental results and provides a detailed understanding of the effects of tangential slot blowing on the flowfield about the isolated F/A-18 forebody. Additionally, it extends the slot-blowing database to transonic maneuvering Mach numbers.

  10. Modification of Slot-Machine Preferences through the Use of a Conditional Discrimination Paradigm

    PubMed Central

    Zlomke, Kimberly R; Dixon, Mark R

    2006-01-01

    The present experiment investigated the impact of contextually trained discriminations on gambling behavior. Nine recreational slot-machine players were initially exposed to concurrently available computerized slot machines that were each programmed on random-ratio schedules of reinforcement and differed only in color. All participants distributed responding equally across the two slot machines. A conditional discrimination procedure was then used to teach the contextual cues representing the arbitrary relations of “greater than” and “less than.” Following contextual cue training, participants were reexposed to the concurrent slot-machine task. After training of the contextual cues, a higher proportion of responses were made to the slot machine that shared formal properties (i.e., color) with the contextual cue representing “greater than.” PMID:17020215

  11. Development of Motor Model of Rotor Slot Harmonics for Speed Sensorless Control of Induction Motor

    NASA Astrophysics Data System (ADS)

    Okubo, Tatsuya; Ishida, Muneaki; Doki, Shinji

    This paper proposes a novel mathematical dynamic model to represent steady-state and transient-state characteristics of rotor slot harmonics of an induction motor for sensorless control. Although it is well known that the rotor slot harmonics originate from the mechanical structure of the induction motor, a mathematical model that describes the relationship between stator/rotor currents of the induction motor and the slot harmonics has not yet been proposed. Therefore, in this paper, a three-phase model of the induction motor that depicts the rotor slot harmonics is developed by taking into consideration the magnetomotive force harmonics and the change in the magnetic air gap caused by the rotor slots. Moreover, the validity of the proposed model is verified by comparing the experimental results and the calculated values.

  12. Capacity analysis of a bypass of roundabouts

    NASA Astrophysics Data System (ADS)

    Sedlačik, Ivan; Slabý, Petr

    2017-09-01

    The capacity of the roads network mainly depends on the capacity of its nodal points - intersections. A connecting branch or a bypass is a lane or lanes inserted between two adjacent branches of a roundabout, providing redirection of vehicles, that would otherwise burden a circular lane. A bypass effect to the capacity of roundabouts, but also other types of level intersections, is undeniable. A connecting branch increases the total capacity of an intersection that takes a part of vehicles performing a manoeuver of the first right turn completely out of an intersection area. Redirecting vehicles reduces delay times at intersections and reduces queues at the entrance to an intersection. Bypasses improve the quality of transport. Limiting for the capacity of bypasses is the point of disconnection from the entrance into the roundabout and the connection point into the exit from the roundabout. Central parts of the bypasses have minimal effects on the capacity. The length of a bypass has to match with the maximum length of a queue of waiting vehicles at a given intensity level. The article deals with analysis of the bypass capacity at the roundabouts.

  13. Antarctic Fishes.

    ERIC Educational Resources Information Center

    Eastman, Joseph T.; DeVries, Arthur L.

    1986-01-01

    Explains the adaptations to Antarctic waters that Notothenioidei, a group of advanced bony fishes, have exhibited. Discusses the fishes' mechanisms of production of antifreeze properties and their capacities for neutral buoyancy in water. (ML)

  14. Fish Allergy

    MedlinePlus

    ... Basics Facts and Statistics NIAID Resources Allergens Peanut Tree Nuts Milk Egg Wheat Soy Fish Shellfish Sesame ... Basics Facts and Statistics NIAID Resources Allergens Peanut Tree Nuts Milk Egg Wheat Soy Fish Shellfish Sesame ...

  15. Antarctic Fishes.

    ERIC Educational Resources Information Center

    Eastman, Joseph T.; DeVries, Arthur L.

    1986-01-01

    Explains the adaptations to Antarctic waters that Notothenioidei, a group of advanced bony fishes, have exhibited. Discusses the fishes' mechanisms of production of antifreeze properties and their capacities for neutral buoyancy in water. (ML)

  16. Gastric bypass reversal: a 7-year experience.

    PubMed

    Pernar, Luise I M; Kim, Julie J; Shikora, Scott A

    After gastric bypass, some patients develop conditions that ultimately require reversal of the bypass. There are currently few publications on the topic to guide clinicians. To describe the indications, techniques, and outcomes for gastric bypass reversal. Two academic medical centers. We conducted a retrospective chart review of all patients who underwent gastric bypass reversal at our institutions between 2008 and 2015. Information regarding the original operation, the indications for reversal, procedures performed, and the postoperative outcomes were collected and analyzed. Nineteen patients underwent gastric bypass reversal. All but 4 reversal operations were performed laparoscopically. The indications for reversal were malnutrition or excessive weight loss (6 patients); chronic nausea, vomiting, and abdominal pain (5); neuroglycopenia (4); massive small bowel loss due to internal hernia (3); and need for surveillance gastric endoscopy (1). In the perioperative period, 4 patients had a complication that required intervention. Five patients required additional delayed procedures. One patient was lost to follow-up. The remaining patients' mean follow-up was 22±18 months. Symptoms that prompted reversal of the gastric bypass resolved in the majority of patients. However, 1 patient's hypoglycemia did not resolve and 2 continued to have diarrhea. Six patients were weaned off of total parenteral nutrition. Laparoscopic gastric bypass reversal is feasible and well tolerated. The procedure can be employed to treat a variety of conditions that may occur after gastric bypass and the majority of patients benefit, with resolution of symptoms. In a carefully selected patient population, gastric bypass reversal should be considered if conservative approaches to adverse conditions fail. Copyright © 2016 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved.

  17. Gastric bypass reduces fat intake and preference.

    PubMed

    le Roux, Carel W; Bueter, Marco; Theis, Nadine; Werling, Malin; Ashrafian, Hutan; Löwenstein, Christian; Athanasiou, Thanos; Bloom, Stephen R; Spector, Alan C; Olbers, Torsten; Lutz, Thomas A

    2011-10-01

    Roux-en-Y gastric bypass is the most effective therapy for morbid obesity. This study investigated how gastric bypass affects intake of and preference for high-fat food in an experimental (rat) study and within a trial setting (human). Proportion of dietary fat in gastric bypass patients was significantly lower 6 yr after surgery compared with patients after vertical-banded gastroplasty (P = 0.046). Gastric bypass reduced total fat and caloric intake (P < 0.001) and increased standard low-fat chow consumption compared with sham controls (P < 0.001) in rats. Compared with sham-operated rats, gastric bypass rats displayed much lower preferences for Intralipid concentrations > 0.5% in an ascending concentration series (0.005%, 0.01%, 0.05%, 0.1%, 0.5%, 1%, 5%) of two-bottle preference tests (P = 0.005). This effect was demonstrated 10 and 200 days after surgery. However, there was no difference in appetitive or consummatory behavior in the brief access test between the two groups (P = 0.71) using similar Intralipid concentrations (0.005% through 5%). Levels of glucagon-like peptide-1 (GLP-1) were increased after gastric bypass as expected. An oral gavage of 1 ml corn oil after saccharin ingestion in gastric bypass rats induced a conditioned taste aversion. These findings suggest that changes in fat preference may contribute to long-term maintained weight loss after gastric bypass. Postingestive effects of high-fat nutrients resulting in conditioned taste aversion may partially explain this observation; the role of GLP-1 in mediating postprandial responses after gastric bypass requires further investigation.

  18. Gastric bypass reduces fat intake and preference

    PubMed Central

    Bueter, Marco; Theis, Nadine; Werling, Malin; Ashrafian, Hutan; Löwenstein, Christian; Athanasiou, Thanos; Bloom, Stephen R.; Spector, Alan C.; Olbers, Torsten; Lutz, Thomas A.

    2011-01-01

    Roux-en-Y gastric bypass is the most effective therapy for morbid obesity. This study investigated how gastric bypass affects intake of and preference for high-fat food in an experimental (rat) study and within a trial setting (human). Proportion of dietary fat in gastric bypass patients was significantly lower 6 yr after surgery compared with patients after vertical-banded gastroplasty (P = 0.046). Gastric bypass reduced total fat and caloric intake (P < 0.001) and increased standard low-fat chow consumption compared with sham controls (P < 0.001) in rats. Compared with sham-operated rats, gastric bypass rats displayed much lower preferences for Intralipid concentrations > 0.5% in an ascending concentration series (0.005%, 0.01%, 0.05%, 0.1%, 0.5%, 1%, 5%) of two-bottle preference tests (P = 0.005). This effect was demonstrated 10 and 200 days after surgery. However, there was no difference in appetitive or consummatory behavior in the brief access test between the two groups (P = 0.71) using similar Intralipid concentrations (0.005% through 5%). Levels of glucagon-like peptide-1 (GLP-1) were increased after gastric bypass as expected. An oral gavage of 1 ml corn oil after saccharin ingestion in gastric bypass rats induced a conditioned taste aversion. These findings suggest that changes in fat preference may contribute to long-term maintained weight loss after gastric bypass. Postingestive effects of high-fat nutrients resulting in conditioned taste aversion may partially explain this observation; the role of GLP-1 in mediating postprandial responses after gastric bypass requires further investigation. PMID:21734019

  19. Interaction of Two Micro-slot Flames: Heat Release Rate and Flame Shape

    NASA Astrophysics Data System (ADS)

    Kuwana, K.; Kato, S.; Kosugi, A.; Hirasawa, T.; Nakamura, Y.

    2014-11-01

    This paper studies the interaction between two identical micro-slot diffusion flames. Here, we define a micro-slot flame as a slot flame of which the slot width is less than about 1 mm. Because of its smallness, a micro-slot flame has a high heating density and can be used as a small heat source. However, the heat release rate of a single micro-slot flame is limited, and therefore, multiple micro-slot flames may be used to increase total heat release rate. As a first step, this paper considers a situation in which two micro-slot flames are used with certain burner spacing. When two diffusion flames are placed closely, flame shape changes from that of an isolated flame. Studying such flame shape change and resultant change in total heat release rate is the topic of this paper. Experiment is conducted and total heat release rate is measured by integrating CH* chemiluminescence recorded using a CCD camera and an optical filter of the wavelength of 430 nm. Two different burner materials, copper and glass, are tested to study the effect of heat loss to burners. An analytical model is applied to predict flame shape. In addition to the classical Burke-Schumann assumptions, two slot flames are modeled as line sources with zero width, enabling a simple analytical solution for the critical burner spacing at which two flames touch each other. The critical burner spacing is a key parameter that characterizes the interaction between two micro-slot flames. Computational fluid dynamics (CFD) simulations are then conducted to test the validity of the present theory. CFD results are favorably compared with the theoretical prediction.

  20. Fish Dishes.

    ERIC Educational Resources Information Center

    Derby, Marie

    2003-01-01

    Describes an art project that was inspired by Greek pottery, specifically dishes shaped as fish. Explains that fourth-grade students drew a fish shape that was later used to create their clay version of the fish. Discusses how the students examined the pottery to make decisions about color and design. (CMK)

  1. Fish Dishes.

    ERIC Educational Resources Information Center

    Derby, Marie

    2003-01-01

    Describes an art project that was inspired by Greek pottery, specifically dishes shaped as fish. Explains that fourth-grade students drew a fish shape that was later used to create their clay version of the fish. Discusses how the students examined the pottery to make decisions about color and design. (CMK)

  2. Bearing-bypass material system test

    NASA Astrophysics Data System (ADS)

    Crew, John H., Jr.

    1988-01-01

    A material specimen containing a central hole is bolted between two bearing guide plates. An applied load control exerts an applied load, either tension or compression, to one end of the specimen and a bypass load control applies a bypass load to the other end of the specimen. Both load controls have their control inputs supplied by a single input signal generator. The difference between the applied load and the bypass load is transmitted through the bolt and plate to the bearing load cells.

  3. Modeling arbitrarily directed slots that are narrow both in width and depth with regard to the FDTD spatial cell

    SciTech Connect

    Riley, D.J.; Turner, C.D.

    1991-12-31

    The Hybrid Thin-Slot Algorithm (HTSA) integrates a transient integral-equation solution for an aperture in an infinite plane into a finite-difference time-domain (FDTD) code. The technique was introduced for linear apertures and was extended to include wall loss and lossy internal gaskets. A general implementation for arbitrary thin slots is briefly described here. The 3-D FDTD-code TSAR was selected for the implementation. The HTSA does not provide universal solutions to the narrow slot problem, but has merits appropriate for particular applications. The HTSA is restricted to planar slots, but can solve the important case that both the width and depth of the slot are narrow compared to the FDTD spatial cell. IN addition, the HTSA is not bound to the FDTD discrete spatial and time increments, and therefore, high-resolution solutions for the slot physics are possible. The implementation of the HTSA into TSAR is based upon a ``slot data file`` that includes the cell indices where the desired slots are exist within the FDTD mesh. For an HTSA-defined slot, the wall region local to the slot is shorted, and therefore, to change the slot`s topology simply requires altering the file to include the desired cells. 7 refs.

  4. 21 CFR 870.4380 - Cardiopulmonary bypass pump speed control.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Cardiopulmonary bypass pump speed control. 870... Cardiopulmonary bypass pump speed control. (a) Identification. A cardiopulmonary bypass pump speed control is a... control the speed of blood pumps used in cardiopulmonary bypass surgery. (b) Classification. Class...

  5. 21 CFR 870.4380 - Cardiopulmonary bypass pump speed control.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Cardiopulmonary bypass pump speed control. 870... Cardiopulmonary bypass pump speed control. (a) Identification. A cardiopulmonary bypass pump speed control is a... control the speed of blood pumps used in cardiopulmonary bypass surgery. (b) Classification. Class...

  6. 21 CFR 870.4380 - Cardiopulmonary bypass pump speed control.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cardiopulmonary bypass pump speed control. 870... Cardiopulmonary bypass pump speed control. (a) Identification. A cardiopulmonary bypass pump speed control is a... control the speed of blood pumps used in cardiopulmonary bypass surgery. (b) Classification. Class...

  7. 21 CFR 870.4380 - Cardiopulmonary bypass pump speed control.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Cardiopulmonary bypass pump speed control. 870... Cardiopulmonary bypass pump speed control. (a) Identification. A cardiopulmonary bypass pump speed control is a... control the speed of blood pumps used in cardiopulmonary bypass surgery. (b) Classification. Class...

  8. 30 CFR 56.19018 - Overtravel by-pass switches.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Overtravel by-pass switches. 56.19018 Section... Hoisting Hoists § 56.19018 Overtravel by-pass switches. When an overtravel by-pass switch is installed, the... switch is held in the closed position by the hoistman. The overtravel by-pass switch shall...

  9. 30 CFR 57.19018 - Overtravel by-pass switches.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Overtravel by-pass switches. 57.19018 Section... Hoisting Hoists § 57.19018 Overtravel by-pass switches. When an overtravel by-pass switch is installed, the... switch is held in the closed position by the hoistman. The overtravel by-pass switch shall...

  10. 21 CFR 870.4380 - Cardiopulmonary bypass pump speed control.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass pump speed control. 870... Cardiopulmonary bypass pump speed control. (a) Identification. A cardiopulmonary bypass pump speed control is a... control the speed of blood pumps used in cardiopulmonary bypass surgery. (b) Classification. Class...

  11. 30 CFR 57.19018 - Overtravel by-pass switches.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Overtravel by-pass switches. 57.19018 Section... Hoisting Hoists § 57.19018 Overtravel by-pass switches. When an overtravel by-pass switch is installed, the... switch is held in the closed position by the hoistman. The overtravel by-pass switch shall return...

  12. 30 CFR 57.19018 - Overtravel by-pass switches.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Overtravel by-pass switches. 57.19018 Section... Hoisting Hoists § 57.19018 Overtravel by-pass switches. When an overtravel by-pass switch is installed, the... switch is held in the closed position by the hoistman. The overtravel by-pass switch shall return...

  13. 30 CFR 56.19018 - Overtravel by-pass switches.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Overtravel by-pass switches. 56.19018 Section... Hoisting Hoists § 56.19018 Overtravel by-pass switches. When an overtravel by-pass switch is installed, the... switch is held in the closed position by the hoistman. The overtravel by-pass switch shall return...

  14. 30 CFR 56.19018 - Overtravel by-pass switches.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Overtravel by-pass switches. 56.19018 Section... Hoisting Hoists § 56.19018 Overtravel by-pass switches. When an overtravel by-pass switch is installed, the... switch is held in the closed position by the hoistman. The overtravel by-pass switch shall return...

  15. 30 CFR 57.19018 - Overtravel by-pass switches.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Overtravel by-pass switches. 57.19018 Section... Hoisting Hoists § 57.19018 Overtravel by-pass switches. When an overtravel by-pass switch is installed, the... switch is held in the closed position by the hoistman. The overtravel by-pass switch shall return...

  16. 30 CFR 57.19018 - Overtravel by-pass switches.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Overtravel by-pass switches. 57.19018 Section... Hoisting Hoists § 57.19018 Overtravel by-pass switches. When an overtravel by-pass switch is installed, the... switch is held in the closed position by the hoistman. The overtravel by-pass switch shall return...

  17. 30 CFR 56.19018 - Overtravel by-pass switches.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Overtravel by-pass switches. 56.19018 Section... Hoisting Hoists § 56.19018 Overtravel by-pass switches. When an overtravel by-pass switch is installed, the... switch is held in the closed position by the hoistman. The overtravel by-pass switch shall return...

  18. 30 CFR 56.19018 - Overtravel by-pass switches.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Overtravel by-pass switches. 56.19018 Section... Hoisting Hoists § 56.19018 Overtravel by-pass switches. When an overtravel by-pass switch is installed, the... switch is held in the closed position by the hoistman. The overtravel by-pass switch shall return...

  19. 21 CFR 870.4310 - Cardiopulmonary bypass coronary pressure gauge.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Cardiopulmonary bypass coronary pressure gauge... Cardiopulmonary bypass coronary pressure gauge. (a) Identification. A cardiopulmonary bypass coronary pressure gauge is a device used in cardiopulmonary bypass surgery to measure the pressure of the blood...

  20. 21 CFR 870.4310 - Cardiopulmonary bypass coronary pressure gauge.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Cardiopulmonary bypass coronary pressure gauge. (a) Identification. A cardiopulmonary bypass coronary pressure gauge is a device used in cardiopulmonary bypass surgery to measure the pressure of the blood perfusing... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Cardiopulmonary bypass coronary pressure gauge...

  1. 21 CFR 870.4310 - Cardiopulmonary bypass coronary pressure gauge.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Cardiopulmonary bypass coronary pressure gauge. (a) Identification. A cardiopulmonary bypass coronary pressure gauge is a device used in cardiopulmonary bypass surgery to measure the pressure of the blood perfusing... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cardiopulmonary bypass coronary pressure gauge...

  2. 21 CFR 870.4310 - Cardiopulmonary bypass coronary pressure gauge.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Cardiopulmonary bypass coronary pressure gauge. (a) Identification. A cardiopulmonary bypass coronary pressure gauge is a device used in cardiopulmonary bypass surgery to measure the pressure of the blood perfusing... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Cardiopulmonary bypass coronary pressure gauge...

  3. 21 CFR 870.4400 - Cardiopulmonary bypass blood reservoir.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Cardiopulmonary bypass blood reservoir. 870.4400... bypass blood reservoir. (a) Identification. A cardiopulmonary bypass blood reservoir is a device used in conjunction with short-term extracorporeal circulation devices to hold a reserve supply of blood in the bypass...

  4. 21 CFR 870.4400 - Cardiopulmonary bypass blood reservoir.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cardiopulmonary bypass blood reservoir. 870.4400... bypass blood reservoir. (a) Identification. A cardiopulmonary bypass blood reservoir is a device used in conjunction with short-term extracorporeal circulation devices to hold a reserve supply of blood in the bypass...

  5. 21 CFR 870.4400 - Cardiopulmonary bypass blood reservoir.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Cardiopulmonary bypass blood reservoir. 870.4400... bypass blood reservoir. (a) Identification. A cardiopulmonary bypass blood reservoir is a device used in conjunction with short-term extracorporeal circulation devices to hold a reserve supply of blood in the bypass...

  6. 21 CFR 870.4400 - Cardiopulmonary bypass blood reservoir.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass blood reservoir. 870.4400... bypass blood reservoir. (a) Identification. A cardiopulmonary bypass blood reservoir is a device used in conjunction with short-term extracorporeal circulation devices to hold a reserve supply of blood in the bypass...

  7. 21 CFR 870.4400 - Cardiopulmonary bypass blood reservoir.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Cardiopulmonary bypass blood reservoir. 870.4400... bypass blood reservoir. (a) Identification. A cardiopulmonary bypass blood reservoir is a device used in conjunction with short-term extracorporeal circulation devices to hold a reserve supply of blood in the bypass...

  8. Criteria for reducing predation by northern squawfish near juvenile salmonid bypass outfalls at Columbia River Dams

    USGS Publications Warehouse

    Shively, Rip S.; Poe, Thomas P.; Sheer, Mindi B.; Peters, Rock

    1996-01-01

    Predation by northern squawfish (Ptychocheilus oregonensis) has been documented to be significant on emigrating juvenile salmonids near juvenile bypass outfalls at hydroelectric dams on the Columbia River. Criteria for siting juvenile fish bypass outfalls to reduce predation were developed using locational data from radio-tagged northern squawfish in The Dalles Dam trailrace, Columbia River. Radio transmitters were surgically implanted in 164 northern squawfish in 1993 and 1994, and their movements and distribution were monitored. Position estimates of northern squawfish were compared with data from a physical hydraulic model of the dam to estimate water velocities where northern squawfish were located. Eighty-two percent of northern squawfish position estimates were in water velocities ≤110 cm/s in 1993 and ≤90 cm/s in 1994. Fish locations were usually associated with water depths ≤10 m (84% in 1993 and 82% in 1994); 90% were within 110 m of the shore or dam structure in 1993, and 86% were within 80 m in 1994. In a related study at John Day Dam, Columbia River, where the juvenile bypass outfall is located 40 m from shore, water depth is 10 m and water velocities typically exceed 75 cm/s, only 13 of 1443 (0.9%) contacts on radio-tagged northern squawfish were located within 200 m of the bypass outfall. We recommend that new or modified juvenile bypass outfalls on the Columbia River be located in water velocities of ≥100 cm/s, ≥75 m from the shore or dam structure, and in water ≥10 m deep.

  9. Low Average Sidelobe Slot Array Antennas for Radiometer Applications

    NASA Technical Reports Server (NTRS)

    Rengarajan, Sembiam; Zawardzki, Mark S.; Hodges, Richard E.

    2012-01-01

    In radiometer applications, it is required to design antennas that meet low average sidelobe levels and low average return loss over a specified frequency bandwidth. It is a challenge to meet such specifications over a frequency range when one uses resonant elements such as waveguide feed slots. In addition to their inherent narrow frequency band performance, the problem is exacerbated due to modeling errors and manufacturing tolerances. There was a need to develop a design methodology to solve the problem. An iterative design procedure was developed by starting with an array architecture, lattice spacing, aperture distribution, waveguide dimensions, etc. The array was designed using Elliott s technique with appropriate values of the total slot conductance in each radiating waveguide, and the total resistance in each feed waveguide. Subsequently, the array performance was analyzed by the full wave method of moments solution to the pertinent integral equations. Monte Carlo simulations were also carried out to account for amplitude and phase errors introduced for the aperture distribution due to modeling errors as well as manufacturing tolerances. If the design margins for the average sidelobe level and the average return loss were not adequate, array architecture, lattice spacing, aperture distribution, and waveguide dimensions were varied in subsequent iterations. Once the design margins were found to be adequate, the iteration was stopped and a good design was achieved. A symmetric array architecture was found to meet the design specification with adequate margin. The specifications were near 40 dB for angular regions beyond 30 degrees from broadside. Separable Taylor distribution with nbar=4 and 35 dB sidelobe specification was chosen for each principal plane. A non-separable distribution obtained by the genetic algorithm was found to have similar characteristics. The element spacing was obtained to provide the required beamwidth and close to a null in the E

  10. Frataxin-bypassing Isu1: characterization of the bypass activity in cells and mitochondria.

    PubMed

    Yoon, Heeyong; Knight, Simon A B; Pandey, Alok; Pain, Jayashree; Zhang, Yan; Pain, Debkumar; Dancis, Andrew

    2014-04-01

    Frataxin is a conserved mitochondrial protein, and deficiency underlies the neurodegenerative disease Friedreich's ataxia. Frataxin interacts with the core machinery for Fe-S cluster assembly in mitochondria. Recently we reported that in frataxin-deleted yeast strains, a spontaneously occurring mutation in one of two genes encoding redundant Isu scaffold proteins, bypassed the mutant phenotypes. In the present study we created strains expressing a single scaffold protein, either Isu1 or the bypass mutant M107I Isu1. Our results show that in the frataxin-deletion strain expressing the bypass mutant Isu1, cell growth, Fe-S cluster protein activities, haem proteins and iron homoeostasis were restored to normal or close to normal. The bypass effects were not mediated by changes in Isu1 expression level. The persulfide-forming activity of the cysteine desulfurase was diminished in the frataxin deletion (∆yfh1 ISU1) and was improved by expression of the bypass Isu1 (∆yfh1 M107I ISU1). The addition of purified bypass M107I Isu1 protein to a ∆yfh1 lysate conferred similar enhancement of cysteine desulfurase as did frataxin, suggesting that this effect contributed to the bypass mechanism. Fe-S cluster-forming activity in isolated mitochondria was stimulated by the bypass Isu1, albeit at a lower rate. The rescuing effects of the bypass Isu1 point to ways that the core defects in Friedreich's ataxia mitochondria can be restored.

  11. Can VHS Virus Bypass the Protective Immunity Induced by DNA Vaccination in Rainbow Trout?

    PubMed

    Sepúlveda, Dagoberto; Lorenzen, Niels

    2016-01-01

    DNA vaccines encoding viral glycoproteins have been very successful for induction of protective immunity against diseases caused by rhabdoviruses in cultured fish species. However, the vaccine concept is based on a single viral gene and since RNA viruses are known to possess high variability and adaptation capacity, this work aimed at evaluating whether viral haemorrhagic septicaemia virus (VHSV), an RNA virus and member of Rhabdoviridae family, was able to evade the protective immune response induced by the DNA vaccination of rainbow trout. The experiments comprised repeated passages of a highly pathogenic VHSV isolate in a fish cell line in the presence of neutralizing fish serum (in vitro approach), and in rainbow trout immunized with the VHS DNA vaccine (in vivo approach). For the in vitro approach, the virus collected from the last passage (passaged virus) was as sensitive as the parental virus to serum neutralization, suggesting that the passaging did not promote the selection of virus populations able to bypass the neutralization by serum antibodies. Also, in the in vivo approach, where virus was passaged several times in vaccinated fish, no increased virulence nor increased persistence in vaccinated fish was observed in comparison with the parental virus. However, some of the vaccinated fish did get infected and could transmit the infection to naïve cohabitant fish. The results demonstrated that the DNA vaccine induced a robust protection, but also that the immunity was non-sterile. It is consequently important not to consider vaccinated fish as virus free in veterinary terms.

  12. Can VHS Virus Bypass the Protective Immunity Induced by DNA Vaccination in Rainbow Trout?

    PubMed Central

    Sepúlveda, Dagoberto; Lorenzen, Niels

    2016-01-01

    DNA vaccines encoding viral glycoproteins have been very successful for induction of protective immunity against diseases caused by rhabdoviruses in cultured fish species. However, the vaccine concept is based on a single viral gene and since RNA viruses are known to possess high variability and adaptation capacity, this work aimed at evaluating whether viral haemorrhagic septicaemia virus (VHSV), an RNA virus and member of Rhabdoviridae family, was able to evade the protective immune response induced by the DNA vaccination of rainbow trout. The experiments comprised repeated passages of a highly pathogenic VHSV isolate in a fish cell line in the presence of neutralizing fish serum (in vitro approach), and in rainbow trout immunized with the VHS DNA vaccine (in vivo approach). For the in vitro approach, the virus collected from the last passage (passaged virus) was as sensitive as the parental virus to serum neutralization, suggesting that the passaging did not promote the selection of virus populations able to bypass the neutralization by serum antibodies. Also, in the in vivo approach, where virus was passaged several times in vaccinated fish, no increased virulence nor increased persistence in vaccinated fish was observed in comparison with the parental virus. However, some of the vaccinated fish did get infected and could transmit the infection to naïve cohabitant fish. The results demonstrated that the DNA vaccine induced a robust protection, but also that the immunity was non-sterile. It is consequently important not to consider vaccinated fish as virus free in veterinary terms. PMID:27054895

  13. Exhaust gas bypass valve control for thermoelectric generator

    SciTech Connect

    Reynolds, Michael G; Yang, Jihui; Meisner, Greogry P.; Stabler, Francis R.; De Bock, Hendrik Pieter Jacobus; Anderson, Todd Alan

    2012-09-04

    A method of controlling engine exhaust flow through at least one of an exhaust bypass and a thermoelectric device via a bypass valve is provided. The method includes: determining a mass flow of exhaust exiting an engine; determining a desired exhaust pressure based on the mass flow of exhaust; comparing the desired exhaust pressure to a determined exhaust pressure; and determining a bypass valve control value based on the comparing, wherein the bypass valve control value is used to control the bypass valve.

  14. Gastric infarction following gastric bypass surgery.

    PubMed

    Do, Patrick H; Kang, Young S; Cahill, Peter

    2016-04-01

    Gastric infarction is an extremely rare occurrence owing to the stomach's extensive vascular supply. We report an unusual case of gastric infarction following gastric bypass surgery. We describe the imaging findings and discuss possible causes of this condition.

  15. Heart bypass surgery - minimally invasive - discharge

    MedlinePlus

    ... thrombosis, 9th ed: American College of Chest Physicians evidence-based clinical practice guidelines. Chest . 2012;141(2 ... bypass surgery - minimally invasive Heart failure - overview High blood cholesterol ...

  16. A Novel Triangular Shaped UWB Fractal Antenna Using Circular Slot

    NASA Astrophysics Data System (ADS)

    Shahu, Babu Lal; Pal, Srikanta; Chattoraj, Neela

    2016-03-01

    The article presents the design of triangular shaped fractal based antenna with circular slot for ultra wideband (UWB) application. The antenna is fed using microstrip line and has overall dimension of 24×24×1.6 mm3. The proposed antenna is covering the wide frequency bandwidth of 2.99-11.16 GHz and is achieved using simple fractal based triangular-circular geometries and asymmetrical ground plane. The antenna is designed and parametrical studies are performed using method of moment (MOM) based Full Wave Electromagnetic (EM) software Simulator Zeland IE3D. The prototype of proposed antenna is fabricated and tested to compare the simulated and measured results of various antenna parameters. The antenna has good impedance bandwidth, nearly constant gain and stable radiation pattern. Measured return loss shows fair agreement with simulated one. Also measured group delay variation obtained is less than 1.0 ns, which proves good time domain behavior of the proposed antenna.

  17. Predictors of irrational thinking in regular slot machine gamblers.

    PubMed

    Delfabbro, P H; Winefield, A H

    2000-03-01

    Previous research has suggested that irrational thinking may play a central role in the maintenance of behavior in slot machine gambling (M. B. Walker, 1992b). The present study is an evaluation of the validity and predictors of irrational thinking in a sample of regular gamblers (N = 20) drawn from the general community. The results were generally consistent with earlier findings; 75% of gambling-related cognitions were found to be irrational. Irrationality was unrelated to the amount of money lost or won during sessions but was positively related to risk taking. The most common irrational cognitions included false beliefs concerning the extent to which outcomes could be controlled or predicted and the attribution of human qualities (personification) to gambling devices. Gender comparisons showed that women were more likely than men to personify the machines. The validity of the speaking-aloud approach and suggestions for future research are discussed.

  18. Slot antenna on a photonic crystal substrate: Green's function study

    NASA Astrophysics Data System (ADS)

    Caloz, Christophe; Curcio, Domenico; Alvarez-Melcon, Alejandro; Skrivervik, Anja K.; Gardiol, Fred E.

    1999-11-01

    A magnetic field Green's function expressed as an eigenmodes expansion and based on the plane wave method is formulated first for an infinite magnetic current line embedded in an unbounded 2D photonic crystal (PC) and then for a magnetic dipole embedded in a 2D PC truncated by two metallic plates. The underlying idea of analyzing a slot antenna printed on a 2D PC with a standard method of moment through the principle of equivalence is shown to motivate the present investigation. A complete solution for the line problem is derived, whereas the inadequacy of the method in nits present form for the dipole problem is demonstrated rigorously. Numerical results of the Green's function for the first problem are shown for different positions of the source, and a discussion about radiation patterns, asymptotic behaviors and convergence problems of the Green's function is proposed.

  19. Optimized cross-slot flow geometry for microfluidic extensional rheometry.

    PubMed

    Haward, Simon J; Oliveira, Mónica S N; Alves, Manuel A; McKinley, Gareth H

    2012-09-21

    A precision-machined cross-slot flow geometry with a shape that has been optimized by numerical simulation of the fluid kinematics is fabricated and used to measure the extensional viscosity of a dilute polymer solution. Full-field birefringence microscopy is used to monitor the evolution and growth of macromolecular anisotropy along the stagnation point streamline, and we observe the formation of a strong and uniform birefringent strand when the dimensionless flow strength exceeds a critical Weissenberg number Wi(crit) ≈ 0.5. Birefringence and bulk pressure drop measurements provide self-consistent estimates of the planar extensional viscosity of the fluid over a wide range of deformation rates (26 s(-1) ≤ ε ≤ 435 s(-1)) and are also in close agreement with numerical simulations performed by using a finitely extensible nonlinear elastic dumbbell model.

  20. Resources masquerading as slots: Flexible allocation of visual working memory.

    PubMed

    Donkin, Chris; Kary, Arthur; Tahir, Fatima; Taylor, Robert

    2016-03-01

    Whether the capacity of visual working memory is better characterized by an item-based or a resource-based account continues to be keenly debated. Here, we propose that visual working memory is a flexible resource that is sometimes deployed in a slot-like manner. We develop a computational model that can either encode all items in a memory set, or encode only a subset of those items. A fixed-capacity mnemonic resource is divided among the items in memory. When fewer items are encoded, they are each remembered with higher fidelity, but at the cost of having to rely on an explicit guessing process when probed about an item that is not in memory. We use the new model to test the prediction that participants will more often encode the entire set of items when the demands on memory are predictable. Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.

  1. A tunable microwave slot antenna based on graphene

    SciTech Connect

    Dragoman, Mircea; Aldrigo, Martino; Vasilache, D.; Dinescu, A.; Neculoiu, Dan; Bunea, Alina-Cristina; Deligeorgis, George; Konstantinidis, George; Mencarelli, Davide; Pierantoni, Luca; Modreanu, M.

    2015-04-13

    The paper presents the experimental and modeling results of a microwave slot antenna in a coplanar configuration based on graphene. The antennas are fabricated on a 4 in. high-resistivity Si wafer, with a ∼300 nm SiO{sub 2} layer grown through thermal oxidation. A CVD grown graphene layer is transferred on the SiO{sub 2}. The paper shows that the reflection parameter of the antenna can be tuned by a DC voltage. 2D radiation patterns at various frequencies in the X band (8–12 GHz) are then presented using as antenna backside a microwave absorbent and a metalized surface. Although the radiation efficiency is lower than a metallic antenna, the graphene antenna is a wideband antenna while the metal antennas with the same geometry and working at the same frequencies are narrowband.

  2. A Novel Triangular Shaped UWB Fractal Antenna Using Circular Slot

    NASA Astrophysics Data System (ADS)

    Shahu, Babu Lal; Pal, Srikanta; Chattoraj, Neela

    2016-03-01

    The article presents the design of triangular shaped fractal based antenna with circular slot for ultra wideband (UWB) application. The antenna is fed using microstrip line and has overall dimension of 24×24×1.6 mm3. The proposed antenna is covering the wide frequency bandwidth of 2.99-11.16 GHz and is achieved using simple fractal based triangular-circular geometries and asymmetrical ground plane. The antenna is designed and parametrical studies are performed using method of moment (MOM) based Full Wave Electromagnetic (EM) software Simulator Zeland IE3D. The prototype of proposed antenna is fabricated and tested to compare the simulated and measured results of various antenna parameters. The antenna has good impedance bandwidth, nearly constant gain and stable radiation pattern. Measured return loss shows fair agreement with simulated one. Also measured group delay variation obtained is less than 1.0 ns, which proves good time domain behavior of the proposed antenna.

  3. Surface conditioning of 316LVM slotted tube cardiovascular stents.

    PubMed

    Raval, Ankur; Choubey, Animesh; Engineer, Chhaya; Kothwala, Devesh

    2005-01-01

    The surface quality of coronary stents has a significant influence on its biocompatibility. Therefore, surface polishing is of paramount importance in the production and application of stents. In the present study, electropolishing is performed on 316LVM steel slotted tube coronary stents. Additionally, acid pickling, as a pretreatment of electropolishing, is also conducted. Gravimetric analysis of the stents (weight loss and strut width change) in the process of acid pickling and electropolishing are done. Qualitative roughness measurements are made to evaluate the stent surface. Electropolished stents are passivated causing chromium enrichment on the surface of the material, thereby enhancing its corrosion resistance. Passivated and electropolished samples are examined using energy dispersive spectrometry. Balloon expanded and crimped profiles of the passivated stents are qualitatively analyzed.

  4. Silicone Rubber Superstrate Loaded Patch Antenna Design Using Slotting Technique

    NASA Astrophysics Data System (ADS)

    Kaur, Bhupinder; Saini, Garima; Saini, Ashish

    2016-09-01

    For the protection of antenna from external environmental conditions, there is a need that antenna should be covered with a stable, non-reactive, highly durable and weather resistive material which is insensitive to changing external environment. Hence, in this paper silicone rubber is proposed as a superstrate layer for patch antenna for its protection. The electrical properties of silicon rubber sealant are experimentally found out and its effect of using as superstrate on coaxial fed microstrip patch antenna using transmission line model is observed. The overall performance is degraded by slightly after the use of superstrate. Further to improve the performance of superstrate loaded antenna, patch slots and ground defects have been proposed. The proposed design achieves the wideband of 790 MHz (13.59 %), gain of 7.12 dB, VSWR of 1.12 and efficiency of 83.02 %.

  5. A single and double slotting radial acoustic metamaterial plate

    NASA Astrophysics Data System (ADS)

    Gao, Nansha; Hou, Hong; Xin, Hang

    2017-04-01

    This paper presents the low-frequency acoustic properties of a new single and double slotting radial acoustic metamaterial plate which is arranged in the axial coordinate. The band structures, transmission spectra, and eigenmode displacement fields of this kind of acoustic metamaterial are different from previous studies. Numerical calculation results show that the first-order band gap (BG) of the radial flexible elastic metamaterial plate is below 200 Hz. A multiple-vibration coupling mechanism is proposed to explain the low-frequency band gaps. By changing the geometric parameters a, t, and g, the location and width of the low-frequency band gaps can be varied neatly. In summary, rational design of geometries and materials is the crucial pathway to open and lower BGs, and could restrain low-frequency vibration similarly. This can be used to protect infrasound, generate filters, and design acoustic devices.

  6. Tunable storage states' transition in slotted ferromagnetic nanorings

    NASA Astrophysics Data System (ADS)

    Zhou, Kan; Wang, Xiaokun; Li, Shichao; Liu, Bailin; Zhang, Baoshan; Tang, Dongming; Yang, Yi

    2017-03-01

    In magnetic random access memory, free layers are used to store data bits as "0" or "1." For free layers with slotted nanoring structures, the magnetization configuration of counterclockwise vortex state can be defined as "0" state, while clockwise vortex state as "1" state. It is important to have a controllable and stable state transition process to make sure that "0" state can switch to "1" state and vice versa. Up to now, it has seldom been reported that the transition process is heavily affected by the static anisotropy field Hk-stat of free layers. A sufficient Hk-stat will substantially reduce the probability of successful state transition. To increase the accuracy of writing data, the free layers must be prepared with a low anisotropy field. In this paper, we present a rotational sputtering method, which can finish the desired isotropic film preparation, and thus realize a stable state transition.

  7. Coal charge lateral contraction in the slot oven

    SciTech Connect

    Addes, V.I.

    1993-01-01

    Prediction and control of coke oven pushing performance is extremely important since it affects battery life and cost of operation. Experience at Inland Steel's coke batteries clearly indicates that, while many factors affect the ability to push coke, coal charge shrinkage is one of the main parameters determining pushing performance of the ovens. The magnitude of shrinkage required for a successful push of the coke cake depends on wall conditions and generally increases with oven deterioration due to age or poor operation. In order to fully understand the shrinkage phenomenon, a study of coal charge lateral contraction in the slot oven was initiated at Inland several years ago. In addition to the lateral contraction a number of other parameters were also monitored during trials. They included coal quality information and such operating parameters like bulk density, charge center temperature, wall pressure, etc. Moreover, coal charge vertical shrinkage measurements utilizing the procedure developed earlier were carried out, too.

  8. Applications of the Sensor Fish Technology

    SciTech Connect

    Deng, Zhiqun; Carlson, Thomas J.; Duncan, Joanne P.; Richmond, Marshall C.

    2007-08-28

    The Sensor Fish is an autonomous device developed at Pacific Northwest National Laboratory for U.S. Department of Energy (DOE) and Army Corps of Engineers (COE) to better understand the physical conditions fish experience during passage through hydro-turbines and other dam bypass alternatives. Since its initial development in 1997, the Sensor Fish has undergone several design changes to improve its function and extend the range of its use. The most recent Sensor Fish design, the six-degree-of-freedom (6DOF) device, has been deployed successfully to characterize the environment fish experience when they pass through several hydroelectric projects along main stem Columbia and Snake Rivers in the Pacific Northwest. Just as information gathered from crash test dummies can affect automobile design with the installation of protective designs to lessen or prevent human injury, having sensor fish data to quantify accelerations, rotations, and pressure changes, helps identify fish injury mechanisms such as strike, turbulent shear, pressure, and inertial effects, including non-lethal ones such as stunning or signs of vestibular disruption that expose fish to a higher risk of predation by birds and piscivorous fish downstream following passage.

  9. Bypass diode for a solar cell

    DOEpatents

    Rim, Seung Bum [Palo Alto, CA; Kim, Taeseok [San Jose, CA; Smith, David D [Campbell, CA; Cousins, Peter J [Menlo Park, CA

    2012-03-13

    Bypass diodes for solar cells are described. In one embodiment, a bypass diode for a solar cell includes a substrate of the solar cell. A first conductive region is disposed above the substrate, the first conductive region of a first conductivity type. A second conductive region is disposed on the first conductive region, the second conductive region of a second conductivity type opposite the first conductivity type.

  10. Prophylactic digitalization for coronary artery bypass surgery.

    PubMed

    Johnson, L W; Dickstein, R A; Fruehan, C T; Kane, P; Potts, J L; Smulyan, H; Webb, W R; Eich, R H

    1976-05-01

    One hundred and twenty patients undergoing aortocoronary bypass procedures were randomly placed into control and digitalized groups. All were initially in normal sinus rhythm and without evidence of congestive heart failure. Supraventricular arrhythmias occurred in 17 of 66 controls and in only three of 54 digitalized patients (P less than 0.01). There was no evidence of digitals toxicity. Based on this evidence we recommend prophylactic digitalization for patients having aortocoronary bypass operations.

  11. Monsanto may bypass NIH in microbe test.

    PubMed

    Sun, Marjorie

    1985-01-11

    The Monsanto Company is planning to ask the Environmental Protection Agency for clearance to field test a genetically engineered microbial pesticide, bypassing the traditional approval process of the National Institutes of Health. Although only federally funded institutions are required to obtain NIH approval for genetic engineering tests, Monsanto is the first company to bypass the NIH regulatory process, which has become mired in a lawsuit brought by Jeremy Rifkin.

  12. Integration of carbon nanotubes in slot waveguides (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Durán-Valdeiglesias, Elena; Zhang, Weiwei; Hoang, Thi Hong Cam; Alonso-Ramos, Carlos; Serna, Samuel; Le Roux, Xavier; Cassan, Eric; Balestrieri, Matteo; Keita, Al-Saleh; Sarti, Francesco; Biccari, Francesco; Torrini, Ughetta; Vinattieri, Anna; Yang, Hongliu; Bezugly, Viktor; Cuniberti, Gianaurelio; Filoramo, Arianna; Gurioli, Massimo; Vivien, Laurent

    2016-05-01

    Demanding applications such as video streaming, social networking, or web search relay on a large network of data centres, interconnected through optical links. The ever-growing data rates and power consumption inside these data centres are pushing copper links close to their fundamental limits. Optical interconnects are being extensively studied with the purpose of solving these limitations. Among the different possible technology platforms, silicon photonics, due to its compatibility with the CMOS platform, has become one of the preferred solutions for the development of the future generation photonic interconnects. However, the on-chip integration of all photonic and optoelectronic building blocks (sources, modulators and detectors…) is very complex and is not cost-effective due to the various materials involved (Ge for detection, doped Si for modulators and III-V for lasing). Carbon nanotubes (CNTs) are nanomaterials of great interest in photonics thanks to their fundamental optical properties, including near-IR room-temperature foto- and electro- luminescence, Stark effect, Kerr effect and absorption. In consequence, CNTs have the ability to emit, modulate and detect light in the telecommunications wavelength range. Furthermore, they are being extensively developed for new nano-electronics applications. In this work, we propose to use CNTs as active material integrated into silicon photonics for the development of all optoelectronic devices. Here, we report on the development of new integration schemes to couple the light emission from CNTs into optical resonators implemented on the silicon-on-insulator and silicon-nitride-on-insulator platforms. A theoretical and experimental analysis of the light interaction of CNTs with micro-ring resonators based on strip and slot waveguides and slot photonic crystal heterostructure cavities were carried out.

  13. MHD Energy Bypass Scramjet Engine

    NASA Technical Reports Server (NTRS)

    Mehta, Unmeel B.; Bogdanoff, David W.; Park, Chul; Arnold, Jim (Technical Monitor)

    2001-01-01

    Revolutionary rather than evolutionary changes in propulsion systems are most likely to decrease cost of space transportation and to provide a global range capability. Hypersonic air-breathing propulsion is a revolutionary propulsion system. The performance of scramjet engines can be improved by the AJAX energy management concept. A magneto-hydro-dynamics (MHD) generator controls the flow and extracts flow energy in the engine inlet and a MHD accelerator downstream of the combustor accelerates the nozzle flow. A progress report toward developing the MHD technology is presented herein. Recent theoretical efforts are reviewed and ongoing experimental efforts are discussed. The latter efforts also include an ongoing collaboration between NASA, the US Air Force Research Laboratory, US industry, and Russian scientific organizations. Two of the critical technologies, the ionization of the air and the MHD accelerator, are briefly discussed. Examples of limiting the combustor entrance Mach number to a low supersonic value with a MHD energy bypass scheme are presented, demonstrating an improvement in scramjet performance. The results for a simplified design of an aerospace plane show that the specific impulse of the MHD-bypass system is better than the non-MHD system and typical rocket over a narrow region of flight speeds and design parameters. Equilibrium ionization and non-equilibrium ionization are discussed. The thermodynamic condition of air at the entrance of the engine inlet determines the method of ionization. The required external power for non-equilibrium ionization is computed. There have been many experiments in which electrical power generation has successfully been achieved by magneto-hydrodynamic (MHD) means. However, relatively few experiments have been made to date for the reverse case of achieving gas acceleration by the MHD means. An experiment in a shock tunnel is described in which MHD acceleration is investigated experimentally. MHD has several

  14. Calculation of the coupling impedances of holes and slots on the liner using MAFIA and scaling

    SciTech Connect

    Thiagarajan, V.; Barts, T.; Kurennoy, S.; Chou, W.

    1993-11-01

    The location of a liner inside the beam tube is one of the options considered for the Super Colliders. The liner could serve as a synchrotron radiation intercept and also help enhance the vacuum. A definite distribution of holes or slots is required to be located on the liner for pumping out the desorbing gases. There will be wake fields propagating within the liner due to diffraction at discontinuities following the incident beam fields. The effect of these wake fields can be minimized by adopting the least number of pumping holes/slots required and through an optimal choice of hole/slot shape and size. The effect of the wake fields on the beam may be expressed through coupling impedances defined proportional to the corresponding forces integrated through distance per unit charge. It is necessary to compute the impedance of holes and slots and determine the scaling of the impedance with the dimensions of the hole/slot and the liner, in order to optimize the choice of pumping holes/slots. The coupling impedances of slots and holes have been calculated here using the code MAFIA and the scaling assessed. The results compare favorably with existing analytical results.

  15. Study on wake structure characteristics of a slotted micro-ramp with large-eddy simulation

    NASA Astrophysics Data System (ADS)

    Dong, Xiangrui; Chen, Yaohui; Dong, Gang; Liu, Yixin

    2017-06-01

    In this paper, a novel slotted ramp-type micro vortex generator (slotted micro-ramp) for flow separation control is simulated in the supersonic flow of Ma = 1.5, based on large eddy simulation combined with the finite volume method. The wake structure characteristics and control mechanisms of both slotted and standard micro-ramps are presented and discussed. The results show that the wake of standard micro-ramp includes a primary counter-rotating streamwise vortex pair, a train of vortex rings, and secondary vortices. The slotted micro-ramp has more complicated wake structures, which contain a confluent counter-rotating streamwise vortex pair and additional streamwise vortices, with the same rotation generated by slot and the vortex rings enveloping the vortex pair. The additional vortices generated by the slot of the micro-ramp can mix with the primary counter-rotating vortex pair, extend the life time, and strengthen the vortex intensity of primary vortex pair. Moreover, the slot can effectively alleviate, or even eliminate the backflow and decrease the profile drag induced by the standard micro-ramp, therefore improving the efficiency of separation control.

  16. Slot spiral antenna modeling using hybrid/mixed FE-BI technique

    NASA Technical Reports Server (NTRS)

    Gong, Jian; Volakis, John L.

    1995-01-01

    This report is concerned with the numerical simulation of the printed slot spiral antenna (SSA) using the finite element - boundary integral (FE-BI) analysis. It has been reported that the FE-BI technique is suited for modeling microstrip patch antennas of any shape, printed on layered planar structure or cylindrical platform and fed with a coaxial cable or a microstripline network underneath the radiating elements. However, direct application of the hybrid FE-BI technique to thin slot spirals requires excessive sampling rates to accurately simulate the geometry. To alleviate the meshing/modeling difficulties encountered with cavity-backed slot antennas, we describe a mixed finite element-boundary integral formulation. As in the past, the boundary integral is used to describe the radiation of the slot above the cavity. However the cavity is now modeled using a suitable mix of edge and node elements. The latter are used only at the aperture of the thin slot so that the nodes follow the center line of the slot. In this manner, regular size elements can be used regardless of the slot's width and any meshing restrictions are substantially relaxed. The proposed mixed element FE-BI formulation introduces three different computational regions and as expected this complicates the generation of the discrete system.

  17. 100-GHz Phase Switch/Mixer Containing a Slot-Line Transition

    NASA Technical Reports Server (NTRS)

    Gaier, Todd; Wells, Mary; Dawson, Douglas

    2009-01-01

    A circuit that can function as a phase switch, frequency mixer, or frequency multiplier operates over a broad frequency range in the vicinity of 100 GHz. Among the most notable features of this circuit is a grounded uniplanar transition (in effect, a balun) between a slot line and one of two coplanar waveguides (CPWs). The design of this circuit is well suited to integration of the circuit into a microwave monolithic integrated circuit (MMIC) package. One CPW is located at the input end and one at the output end of the top side of a substrate on which the circuit is fabricated (see Figure 1). The input CPW feeds the input signal to antiparallel flip-chip Schottky diodes connected to the edges of the slot line. Phase switching is effected by the combination of (1) the abrupt transition from the input CPW to the slot line and (2) CPW ground tuning effected by switching of the bias on the diodes. Grounding of the slot metal to the bottom metal gives rise to a frequency cutoff in the slot. This cutoff is valuable for separating different frequency components when the circuit is used as a mixer or multiplier. Proceeding along the slot line toward the output end, one encounters the aforementioned transition, which couples the slot line to the output CPW. Impedance tuning of the transition is accomplished by use of a high-impedance section immediately before the transition.

  18. A finite element model of the tuning slot of labial organ pipes.

    PubMed

    Rucz, Péter; Augusztinovicz, Fülöp; Angster, Judit; Preukschat, Tim; Miklós, András

    2015-03-01

    An acoustic model suitable for the characterization of tuning slots of labial organ pipes is presented in this paper. Since the tuning slot arrangement is similar (but not identical) to that of toneholes in woodwind instruments, the adaptability of the well-established tonehole model for the specific problem is examined. A numerical model utilizing the finite element (FE) and perfectly matched layer techniques is set up for the simulation of tuning slots with design parameters varying over a wide range. Analytical tonehole models and the proposed numerical tuning slot model are both combined with analytical one-dimensional waveguide models to predict the acoustic behavior of tuning slot pipes. Comparison to measurements carried out on experimental pipes proves that the hybrid waveguide/FE model can predict the most important properties of the tuning slot pipe with good accuracy. The finite element method (FEM) also overcomes the limitations of traditional tonehole models relying on the equivalent T-circuit approximation. By means of the FE model the eigenfrequency-structure and its impact on the character of the sound can be foretold in the design phase, by which a more efficient scaling of tuning slot pipes can be achieved.

  19. Thrust reverser for high bypass turbofan engine

    SciTech Connect

    Matta, R.K.; Bhutiani, P.K.

    1990-05-08

    This patent describes a thrust reverser for a gas turbine engine of the type which includes an outer wall spaced from the center body of a core engine to define a bypass duct therebetween. The thrust reverser comprising: circumferentially displaced blocker doors, each of the doors being movable between a normal position generally aligned with the outer wall and a thrust reversing position extending transversely of the bypass duct for blocking the exhaust of air through the bypass duct and directing the air through an opening in the outer wall for thrust reversal; each of the blocker doors being of lightweight construction and including a pit in the inner surface thereof in the normal position; means for covering the pit during normal flow of air through the bypass duct to reduce the pressure drop in the bypass duct and to reduce noise. The covering means including a pit cover hingedly mounted at one end thereof on the blocker door and means of biasing the pit cover away from the blocker door to a position providing smooth flow of air through the bypass duct during normal operation.

  20. Cardiopulmonary bypass: Evidence or experience based?

    PubMed

    Bartels, Claus; Gerdes, Anja; Babin-Ebell, Jörg; Beyersdorf, Friedhelm; Boeken, Udo; Doenst, Torsten; Feindt, Peter; Heiermann, Michael; Schlensak, Christian; Sievers, Hans-Hinrich

    2002-07-01

    Evidence-based medicine is emerging as a new paradigm for medical practice. The purpose of this study was to evaluate the amount and quality of scientific evidence supporting principles that are currently applied for cardiopulmonary bypass performance. A survey of all German departments of cardiac surgery regarding cardiopulmonary bypass performance disclosed major differences. Consequently, for 48 major principles of cardiopulmonary bypass performance, relevant Medical Subject Headings were identified, and a literature search of the Medline database was performed. Two sequentially applied sets of inclusion-exclusion criteria were selected to assess the best available evidence. Thirty-three thousand articles relating to the subject were identified. Among these, 1500 fulfilled the first set of inclusion criteria: meta-analysis of (randomized) controlled clinical trials and in vitro and animal studies. Rigorous methodological criteria were then applied to further select remaining publications. Ultimately, 225 articles referring to major cardiopulmonary bypass principles were identified as providing the best available evidence. These were graded according to their methodological rigor (susceptibility to bias). The scientific evidence on the investigated cardiopulmonary bypass principles did not prove to be of a high enough level to allow general recommendations to be made. The scientific data concerning the effectiveness and safety of key principles of cardiopulmonary bypass are insufficient in both amount and quality of scientific evidence to serve as a basis for practical, evidence-based guidelines.

  1. Wind Tunnel Results of Pneumatic Forebody Vortex Control Using Rectangular Slots a Chined Forebody

    NASA Technical Reports Server (NTRS)

    Alexander, Michael; Meyn, Larry A.

    1994-01-01

    A subsonic wind tunnel investigation of pneumatic vortex flow control on a chined forebody using slots was accomplished at a dynamic pressure of 50 psf resulting in a R(n)/ft of 1.3 x 10(exp 6). Data were acquired from angles of attack ranging from -4deg to +34deg at side slips of +0.4deg and +10.4deg. The test article used in this study was the 10% scale Fighter Lift and Control (FLAC) advanced diamond winged, vee-tailed fighter configuration. Three different slot blowing concepts were evaluated; outward, downward, and tangential with ail blowing accomplished asymmetrically. The results of three different mass flows (0.067, 0.13, and 0.26 lbm/s; C(sub mu)'s of less than or equal to 0.006, 0.011. and 0.022 respectively) were analyzed and reported. Test data are presented on the effects of mass flows, slot lengths and positions and blowing concepts on yawing moment and side force generation. Results from this study indicate that the outward and downward blowing slots developed yawing moment and side force increments in the direction opposite of the blowing side while the tangential blowing slots generated yawing moment and side force increments in the direction towards the blowing side. The outward and downward blowing slots typically produced positive pitching moment increments while the tangential blowing slots typically generated negative pitching moment increments. The slot blowing nearest the forebody apex was most effective at generating the largest increments and as the slot was moved aft or increased in length, its effectiveness at generating forces and moments diminished.

  2. Fish Rhabdoviruses

    USGS Publications Warehouse

    Kurath, G.; Winton, J.

    2008-01-01

    Many important viral pathogens of fish are members of the family Rhabdoviridae. The viruses in this large group cause significant losses in populations of wild fish as well as among fish reared in aquaculture. Fish rhabdoviruses often have a wide host and geographic range, and infect aquatic animals in both freshwater and seawater. The fish rhabdoviruses comprise a diverse collection of isolates that can be placed in one of two quite different groups: isolates that are members of the established genusNovirhabdovirus, and those that are most similar to members of the genus Vesiculovirus. Because the diseases caused by fish rhabdoviruses are important to aquaculture, diagnostic methods for their detection and identification are well established. In addition to regulations designed to reduce the spread of fish viruses, a significant body of research has addressed methods for the control or prevention of diseases caused by fish rhabdoviruses, including vaccination. The number of reported fish rhabdoviruses continues to grow as a result of the expansion of aquaculture, the increase in global trade, the development of improved diagnostic methods, and heightened surveillance activities. Fish rhabdoviruses serve as useful components of model systems to study vertebrate virus disease, epidemiology, and immunology.

  3. Prediction of Slot Shape and Slot Size for Improving the Performance of Microstrip Antennas Using Knowledge-Based Neural Networks

    PubMed Central

    De, Asok

    2014-01-01

    In the last decade, artificial neural networks have become very popular techniques for computing different performance parameters of microstrip antennas. The proposed work illustrates a knowledge-based neural networks model for predicting the appropriate shape and accurate size of the slot introduced on the radiating patch for achieving desired level of resonance, gain, directivity, antenna efficiency, and radiation efficiency for dual-frequency operation. By incorporating prior knowledge in neural model, the number of required training patterns is drastically reduced. Further, the neural model incorporated with prior knowledge can be used for predicting response in extrapolation region beyond the training patterns region. For validation, a prototype is also fabricated and its performance parameters are measured. A very good agreement is attained between measured, simulated, and predicted results. PMID:27382616

  4. Single-stage experimental evaluation of compressor blading with slots and vortex generators, part 5

    NASA Technical Reports Server (NTRS)

    Brent, J. A.

    1972-01-01

    An experimental investigation was conducted to determine the extent that slots and vortex generators can increase the efficiency and stable operating range of highly loaded compressor stages. With slots in the rotor and stator, the stage performance both with and without vortex generators was inferior to that achieved with the unslotted blading. However, with vortex generators, stator slots, and an unslotted rotor, the stable operating range increased 25% and the stage peak efficiency increased 2.1% over the values achieved with the unslotted rotor and stator without vortex generators, at design equivalent rotor speed.

  5. High-Q silicon-on-insulator slot photonic crystal cavity infiltrated by a liquid

    SciTech Connect

    Caër, Charles; Le Roux, Xavier; Cassan, Eric

    2013-12-16

    We report the experimental realization of a high-Q slot photonic crystal cavity in Silicon-On-Insulator (SOI) configuration infiltrated by a liquid. Loaded Q-factor of 23 000 is measured at telecom wavelength. The intrinsic quality factor inferred from the transmission spectrum is higher than 200 000, which represents a record value for slot photonic crystal cavities on SOI, whereas the maximum of intensity of the cavity is roughly equal to 20% of the light transmitted in the waveguide. This result makes filled slot photonic crystal cavities very promising for silicon-based light emission and ultrafast nonlinear optics.

  6. Resonant-tunnelling diode oscillator using a slot-coupled quasioptical open resonator

    NASA Technical Reports Server (NTRS)

    Stephan, K. D.; Brown, E. R.; Parker, C. D.; Goodhue, W. D.; Chen, C. L.

    1991-01-01

    A resonant-tunneling diode has oscillated at X-band frequencies in a microwave circuit consisting of a slot antenna coupled to a semiconfocal open resonator. Coupling between the open resonator and the slot oscillator improves the noise-to-carrier ratio by about 36 dB relative to that of the slot oscillator alone in the 100-200 kHz range. A circuit operating near 10 GHz has been designed as a scale model for millimeter- and submillimeter-wave applications.

  7. Kinetic theory analysis of rarefied gas flow through finite length slots

    NASA Technical Reports Server (NTRS)

    Raghuraman, P.

    1972-01-01

    An analytic study is made of the flow a rarefied monatomic gas through a two dimensional slot. The parameters of the problem are the ratios of downstream to upstream pressures, the Knudsen number at the high pressure end (based on slot half width) and the length to slot half width ratio. A moment method of solution is used by assuming a discontinuous distribution function consisting of four Maxwellians split equally in angular space. Numerical solutions are obtained for the resulting equations. The characteristics of the transition regime are portrayed. The solutions in the free molecule limit are systematically lower than the results obtained in that limit by more accurate numerical methods.

  8. Proposal of using slot-waveguide cavity to reduce noises in resonant integrated optical gyroscopes

    NASA Astrophysics Data System (ADS)

    Jiang, Yi; Kong, Mei; Xu, Yameng

    2016-10-01

    Resonant optical gyroscopes suffer serious performance degradation induced by noises. We propose using an air-gap silicon-on-silica slot waveguide ring resonator as the resonant cavity of a resonant integrated optical gyroscope. We estimate possible backscattering, Kerr effect, polarization fluctuation, and thermal drift in the air-gap slot waveguide. It is shown that the backscattering, Kerr nonlinearity, and thermal instabilities can decrease significantly compared to those in a common solid-core silicon waveguide cavity, and perturbations of the polarization fluctuation may be eliminated. In addition, a slot-waveguide cavity is more beneficial for integration than a photonic bandgap fiber cavity.

  9. Effect of slot aspect ratio on droplet formation from silicon straight-through microchannels.

    PubMed

    Kobayashi, Isao; Mukataka, Sukekuni; Nakajima, Mitsutoshi

    2004-11-01

    We recently proposed a novel technique for preparing monodisperse emulsions using an array of microfabricated through-holes with an oblong section; we called this array a straight-through microchannel (MC). This paper reports how the slot aspect ratio of the straight-through MC affects droplet formation characteristics. Straight-through MCs with different slot aspect ratios and equivalent diameters of about 20 microm were used. Experimental observation showed that slot aspect ratios exceeding a threshold of approximately 3 were needed to successfully prepare monodisperse emulsions with coefficients of variation below 2%.

  10. Plasmonic analog of electromagnetically-induced transparency of asymmetrical slots waveguide

    NASA Astrophysics Data System (ADS)

    Sun, Lin; Wang, Jicheng; Hu, Zheng-Da; Wang, Xiaosai; Chen, Jing

    2016-02-01

    In this paper, electromagnetically-induced transparency (EIT) phenomena have been investigated numerically in the plasmonic waveguides composed of unsymmetrical slot shaped metal-insulator-metal (MIM) structures. By the transmission line theory and Fabry-Perot model, the formation and evolution mechanisms of plasmon-induced transparency were exactly analyzed. The analysis showed that the peak of EIT-like transmission could be changed easily according to certain rules by adjusting the geometrical parameters of the slot structures, including the coupling distances and slot depths. We can find a new method to design nanoscale optical switch, devices in optical storage and optical computing.

  11. Pressure distributions on a rectangular aspect-ratio-6, slotted supercritical airfoil wing with externally blown flaps

    NASA Technical Reports Server (NTRS)

    Johnson, W. G., Jr.

    1976-01-01

    An investigation was made in the 5.18 m (17 ft) test section of the Langley 300 MPH 7 by 10 foot tunnel on a rectangular, aspect ratio 6 wing which had a slotted supercritical airfoil section and externally blown flaps. The 13 percent thick wing was fitted with two high lift flap systems: single slotted and double slotted. The designations single slotted and double slotted do not include the slot which exists near the trailing edge of the basic slotted supercritical airfoil. Tests were made over an angle of attack range of -6 deg to 20 deg and a thrust-coefficient range up to 1.94 for a free-stream dynamic pressure of 526.7 Pa (11.0 lb/sq ft). The results of the investigation are presented as curves and tabulations of the chordwise pressure distributions at the midsemispan station for the wing and each flap element.

  12. California's Yolo Bypass: Evidence that flood control can be compatible with fisheries, wetlands, wildlife, and agriculture

    USGS Publications Warehouse

    Sommer, T.; Harrell, B.; Nobriga, M.; Brown, R.; Moyle, P.B.; Kimmerer, W.; Schemel, Laurence E.

    2001-01-01

    Unlike conventional flood control systems that frequently isolate rivers from ecologically-essential floodplain habitat, California's Yolo Bypass has been engineered to allow Sacramento Valley floodwaters to inundate a broad floodplain. From a flood control standpoint, the 24,000 ha leveed floodplain has been exceptionally successful based on its ability to convey up to 80% of the flow of the Sacramento River basin during high water events. Agricultural lands and seasonal and permanent wetlands within the bypass provide key habitat for waterfowl migrating through the Pacific Flyway. Our field studies demonstrate that the bypass seasonally supports 42 fish species, 15 of which are native. The floodplain appears to be particularly valuable spawning and rearing habitat for the splittail (Pogonichthys macrolepidotus), a federally-listed cyprinid, and for young chinook salmon (Oncorhynchus tshawytscha), which use the Yolo Bypass as a nursery area. The system may also be an important source to the downstream food web of the San Francisco Estuary as a result of enhanced production of phytoplankton and detrital material. These results suggest that alternative flood control systems can be designed without eliminating floodplain function and processes, key goals of the 1996 Draft AFS Floodplain Management Position Statement.

  13. The Valveless Saphenous Vein Graft Technique for EC-IC High-Flow Bypass: Technical Note.

    PubMed

    Matsukawa, Hidetoshi; Tanikawa, Rokuya; Kamiyama, Hiroyasu; Tsuboi, Toshiyuki; Noda, Kosumo; Ota, Nakao; Miyata, Shiro; Tokuda, Sadahisa

    2016-03-01

    Extracranial to intracranial (EC-IC) high-flow bypass using radial artery or saphenous vein (SV) graft has remained vital for complex aneurysms. If an Allen test is positive, the radial artery cannot be harvested because of poor palmer collateral circulation. The valves are thought to be one of causes of SV graft failure. Herein we illustrate the "valveless SV graft technique" as bypass conduits. Between August 2014 and December 2014 at the Department of Neurosurgery at Teishinkai Hospital, 4 patients whose Allen test was positive underwent EC-IC bypass with the valveless SV graft for complex internal carotid artery (ICA) aneurysm. After SV harvesting, we identified the SV valve, cut it, and performed an end-to-end anastomosis using the fish mouth trimming technique. Graft patency was confirmed by computed tomography angiography. We have not encountered any problems related to graft failure, and all valveless SV grafts were patent during the follow-up period (median, 210 days; interquartile range, 93-287 days). The valveless SV graft technique is a useful technique in patients with complex ICA aneurysms who undergo EC-IC high-flow bypass with therapeutic ICA occlusion and whose Allen tests are positive. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Brain microvascular function during cardiopulmonary bypass

    SciTech Connect

    Sorensen, H.R.; Husum, B.; Waaben, J.; Andersen, K.; Andersen, L.I.; Gefke, K.; Kaarsen, A.L.; Gjedde, A.

    1987-11-01

    Emboli in the brain microvasculature may inhibit brain activity during cardiopulmonary bypass. Such hypothetical blockade, if confirmed, may be responsible for the reduction of cerebral metabolic rate for glucose observed in animals subjected to cardiopulmonary bypass. In previous studies of cerebral blood flow during bypass, brain microcirculation was not evaluated. In the present study in animals (pigs), reduction of the number of perfused capillaries was estimated by measurements of the capillary diffusion capacity for hydrophilic tracers of low permeability. Capillary diffusion capacity, cerebral blood flow, and cerebral metabolic rate for glucose were measured simultaneously by the integral method, different tracers being used with different circulation times. In eight animals subjected to normothermic cardiopulmonary bypass, and seven subjected to hypothermic bypass, cerebral blood flow, cerebral metabolic rate for glucose, and capillary diffusion capacity decreased significantly: cerebral blood flow from 63 to 43 ml/100 gm/min in normothermia and to 34 ml/100 gm/min in hypothermia and cerebral metabolic rate for glucose from 43.0 to 23.0 mumol/100 gm/min in normothermia and to 14.1 mumol/100 gm/min in hypothermia. The capillary diffusion capacity declined markedly from 0.15 to 0.03 ml/100 gm/min in normothermia but only to 0.08 ml/100 gm/min in hypothermia. We conclude that the decrease of cerebral metabolic rate for glucose during normothermic cardiopulmonary bypass is caused by interruption of blood flow through a part of the capillary bed, possibly by microemboli, and that cerebral blood flow is an inadequate indicator of capillary blood flow. Further studies must clarify why normal microvascular function appears to be preserved during hypothermic cardiopulmonary bypass.

  15. Changing trends in emergency coronary bypass surgery.

    PubMed

    Maganti, Manjula; Brister, Stephanie J; Yau, Terrence M; Collins, Susan; Badiwala, Mitesh; Rao, Vivek

    2011-10-01

    Patients undergoing emergency coronary artery bypass grafting represent a unique and high-risk population that remains challenging for cardiac surgeons. We examined the changing trends in patients undergoing emergency bypass grafting over the past 20 years. We conducted a retrospective review of our database between 1990 and 2009 and patients were divided into 2 groups based on year of operation: 1990-1999, n = 393; 2000-2009, n = 184. The primary outcomes of interest for this study are operative mortality and incidence of low cardiac output syndrome. The percentage of patients undergoing emergency coronary bypass grafting has decreased from 2.7% to 1.7% over time. The percentage of patients with dyslipidemia, hypertension, triple vessel disease, peripheral vascular disease, and left main disease increased over time (P < .05). Operative mortality remained at 8.1% in both year groups. Preoperative hypertension, congestive heart failure, left ventricular ejection fraction less than 20%, and previous cardiac surgery independently predicted operative mortality by logistic regression analysis. Low cardiac output syndrome developed in 25% of the patient population undergoing emergency bypass grafting. The independent predictors of low cardiac output syndrome were small body surface area, congestive heart failure, shock, myocardial infarction, earlier decade (1990-1999) and increased age. Despite a changing preoperative risk profile, the operative mortality of emergency coronary artery bypass grafting has remained stable over the years. However, mortality remains significantly above the observed mortality in elective bypass grafting. Continued improvements in the management of heart failure and the care of the elderly will likely result in reduced risks of emergency coronary artery bypass grafting. Copyright © 2011 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

  16. "Orpheus" cardiopulmonary bypass simulation system.

    PubMed

    Morris, Richard W; Pybus, David A

    2007-12-01

    In this paper we describe a high-fidelity perfusion simulation system intended for use in the training and continuing education of perfusionists. The system comprises a hydraulic simulator, an electronic interface unit and a controlling computer with associated real-time computer models. It is designed for use within an actual operating theatre, or within a specialized simulation facility. The hydraulic simulator can be positioned on an operating table and physically connected to the circuit of the institutional heart-lung machine. The institutional monitoring system is used to display the arterial and central venous pressures, the ECG and the nasopharyngeal temperature using appropriate connections. The simulator is able to reproduce the full spectrum of normal and abnormal events that may present during the course of cardiopulmonary bypass. The system incorporates a sophisticated blood gas model that accurately predicts the behavior of a modern, hollow-fiber oxygenator. Output from this model is displayed in the manner of an in-line blood gas electrode and is updated every 500 msecs. The perfusionist is able to administer a wide variety of drugs during a simulation session including: vasoconstrictors (metaraminol, epinephrine and phenylephrine), a vasodilator (sodium nitroprusside), chronotropes (epinephrine and atropine), an inotrope (epinephrine) and modifiers of coagulation (heparin and protamine). Each drug has a pharmacokinetic profile based on a three-compartment model plus an effect compartment. The simulation system has potential roles in the skill training of perfusionists, the development of crisis management protocols, the certification and accreditation of perfusionists and the evaluation of new perfusion equipment and/or techniques.

  17. 14 CFR 93.217 - Allocation of slots for international operations and applicable limitations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... TRAFFIC RULES Allocation of Commuter and Air Carrier IFR Operations at High Density Traffic Airports § 93... available, additional slots during the high density hours shall be allocated at Kennedy Airport for new...

  18. 14 CFR 93.217 - Allocation of slots for international operations and applicable limitations.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... TRAFFIC RULES Allocation of Commuter and Air Carrier IFR Operations at High Density Traffic Airports § 93... available, additional slots during the high density hours shall be allocated at Kennedy Airport for new...

  19. Method and tool for machining a transverse slot about a bore

    NASA Technical Reports Server (NTRS)

    David-Malig, M. A.

    1980-01-01

    A method and apparatus for cutting a transverse slot about a bore of smaller diameter than that of the slot are disclosed. The invention consists of introducing a cutting head facing transversely to the bore, through the bore opening its distance from the mill shaft being progressively extended by the addition of spacers between the head and the shaft until the desired slot depth is obtained. The spacers are held in position by a cable passing from the cutting head through the series of spacers and out along the mill shaft. The mill shaft carrying the cutting head is moved transversely into the object wherein the slot is being cut as the object is being rotated thereabout by the mill table to which it is affixed.

  20. Implementation of rectangular slit-inserted ultra-wideband tapered slot antenna.

    PubMed

    Kim, Sun-Woong; Choi, Dong-You

    2016-01-01

    In this paper, a tapered slot antenna capable of ultra-wideband communication was designed. In the proposed antenna, rectangular slits were inserted to enhance the bandwidth and reduce the area of the antenna. The rectangular slit-inserted tapered slot antenna operated at a bandwidth of 8.45 GHz, and the bandwidth improved upon the basic tapered slot antenna by 4.72 GHz. The radiation pattern of the antenna was suitable for location recognition in a certain direction owing to an appropriate 3 dB beam width. The antenna gain was analyzed within the proposed bandwidth, and the highest gain characteristic at 7.55 dBi was exhibited at a 5-GHz band. The simulation and measurement results of the proposed tapered slot antenna were similar.

  1. 14 CFR 93.217 - Allocation of slots for international operations and applicable limitations.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... TRAFFIC RULES Allocation of Commuter and Air Carrier IFR Operations at High Density Traffic Airports § 93... available, additional slots during the high density hours shall be allocated at Kennedy Airport for...

  2. 14 CFR 93.217 - Allocation of slots for international operations and applicable limitations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... TRAFFIC RULES Allocation of Commuter and Air Carrier IFR Operations at High Density Traffic Airports § 93... available, additional slots during the high density hours shall be allocated at Kennedy Airport for...

  3. Computational Investigation of Tangential Slot Blowing on a Generic Chined Forebody

    NASA Technical Reports Server (NTRS)

    Agosta-Greenman, Roxana M.; Gee, Ken; Cummings, Russell M.; Schiff, Lewis B.

    1995-01-01

    The effect of tangential slot blowing on the flowfield about a generic chined forebody at high angles of attack is investigated numerically using solutions of the thin-layer, Reynolds-averaged, Navier-Stokes equations. The effects of jet mass now ratios, angle of attack, and blowing slot location in the axial and circumferential directions are studied. The computed results compare well with available wind-tunnel experimental data. Computational results show that for a given mass now rate, the yawing moments generated by slot blowing increase as the body angle of attack increases. It is observed that greater changes in the yawing moments are produced by a slot located closest to the lip of the nose. Also, computational solutions show that inboard blowing across the top surface is more effective at generating yawing moments than blowing outboard from the bottom surface.

  4. Gain properties of an uncoated and chiral coated slotted sphere embedded in a chiral background.

    PubMed

    Awan, Z A

    2016-10-10

    The gain properties of an uncoated and a chiral coated slotted sphere embedded in a chiral background have been investigated using numerical simulations. In this paper, it is found that a chiral background medium enhances the gain of an uncoated slotted sphere in the forward direction as compared to the free space background. It is shown that the forward direction gain of a chiral coated slotted sphere embedded in a chiral background increases with the increase in the background chirality. It is further determined that the maximum gain moves away from the polar direction toward the forward direction as the chirality of the coating increases for a fixed background chirality. Also, this maximum gain gradually decreases as the chirality of the coating increases. An interesting feature of an angular window is introduced for a chiral coated slotted sphere embedded in a chiral background where the gain is nearly constant for a specific range of angles.

  5. A hybrid electro-optic polymer and TiO2 double-slot waveguide modulator

    PubMed Central

    Qiu, Feng; Spring, Andrew M.; Maeda, Daisuke; Ozawa, Masa-aki; Odoi, Keisuke; Otomo, Akira; Aoki, Isao; Yokoyama, Shiyoshi

    2015-01-01

    An electro-optic (EO) modulator using a TiO2 slot hybrid waveguide has been designed and fabricated. Optical mode calculations revealed that the mode was primarily confined within the slots when using a double-slot configuration, thus achieving a high EO activity experimentally. The TiO2 slots also acted as an important barrier to induce an enhanced DC field during the poling of the EO polymer and the driving of the EO modulator. The hybrid phase modulator exhibited a driving voltage (Vπ) of 1.6 V at 1550 nm, which can be further reduced to 0.8 V in a 1 cm-long push-pull Mach–Zehnder interferometer (MZI) structure. The modulator demonstrated a low propagation loss of 5 dB/cm and a relatively high end-fire coupling efficiency. PMID:25708425

  6. Design of slotted high quality factor photonic-crystal nanocavities embedded in electro-optic polymers

    NASA Astrophysics Data System (ADS)

    Nakadai, Masahiro; Konoike, Ryotaro; Tanaka, Yoshinori; Asano, Takashi; Noda, Susumu

    2017-09-01

    We improve design quality factors of slotted photonic crystal nanocavities embedded in electro-optic polymers (EOPs), which enables control of resonant wavelengths without the use of light-absorbing free carriers. We form nanocavities by modifying single- and double-slotted line-defect waveguides with lattice-constant modulations analytically determined based on dispersions of the waveguides. A double-slotted nanocavity achieves a fourfold increase in Q factor (36 million) compared to a single-slotted nanocavity with similar modulation of lattice constants. Both structures can realize large concentration of light in the EOP region (50%), and resonant wavelength modulations of ∼0.01% are expected with applied voltage of 2 V.

  7. An Active K-Band Receive Slot Array for Mobile Satellite Communications

    NASA Technical Reports Server (NTRS)

    Tulintseff, A. N.; Lee, K. A.; Sukamto, L. M.; Chew, W.

    1994-01-01

    An active receive slot array has been developed for operation in the downlink frequency band, 19.914-20.064 GHz, of NASA's Advanced Communication Technology Satellite (ACTS) for the ACTS Mobile Terminal (AMT) project.

  8. Low-speed aerodynamic test of an axisymmetric supersonic inlet with variable cowl slot

    NASA Technical Reports Server (NTRS)

    Powell, A. G.; Welge, H. R.; Trefny, C. J.

    1985-01-01

    The experimental low-speed aerodynamic characteristics of an axisymmetric mixed-compression supersonic inlet with variable cowl slot are described. The model consisted of the NASA P-inlet centerbody and redesigned cowl with variable cowl slot powered by the JT8D single-stage fan simulator and driven by an air turbine. The model was tested in the NASA Lewis Research Center 9- by 15-foot low-speed tunnel at Mach numbers of 0, 0.1, and 0.2 over a range of flows, cowl slot openings, centerbody positions, and angles of attack. The variable cowl slot was effective in minimizing lip separation at high velocity ratios, showed good steady-state and dynamic distortion characteristics, and had good angle-of-attack tolerance.

  9. An Active K-Band Receive Slot Array for Mobile Satellite Communications

    NASA Technical Reports Server (NTRS)

    Tulintseff, A. N.; Lee, K. A.; Sukamto, L. M.; Chew, W.

    1994-01-01

    An active receive slot array has been developed for operation in the downlink frequency band, 19.914-20.064 GHz, of NASA's Advanced Communication Technology Satellite (ACTS) for the ACTS Mobile Terminal (AMT) project.

  10. A Computer-Aided Approach for Designing Edge-Slot Waveguide Arrays

    NASA Technical Reports Server (NTRS)

    Gosselin, Renee Brian

    2003-01-01

    Traditional techniques for designing resonant edge-slot waveguide arrays have required an iterative trial-and-error process of measuring slot data from several prototypes. Since very little meaningful data has been published, this technology remains relatively immature and prohibitive for many smaller programs that could benefit from some advantages this antenna has to offer. A new Computer-Aided Design technique for designing resonant edge-slot waveguide arrays was used to successfuliy design such an X-band radiometer antenna for the NASA Light Rainfall Radiometer (LRR) instrument. Having the ability to rapidly create such an extremely accurate and efficient antenna design without the need to manufacture prototypes has also enabled inexpensive research that promises to improve the system-level performance of microwave radiometers for upcoming space-flight missions. This paper will present details of the LRR antenna design and describe some other current edge-slot array accomplishments at Goddard Space Flight Center.

  11. Design of a dual slot antenna for small animal microwave ablation studies.

    PubMed

    Moon, Tyler J; Brace, Christopher L; Moon, Tyler J; Brace, Christopher L; Brace, Christopher L; Moon, Tyler J

    2016-08-01

    This study presents the development of a dual-slot antenna for small animal tumor ablation. By using a dual-slot design at 8 GHz, it was hypothesized that smaller and more spherical ablations can be produced. After computer-aided design optimization, antennas were fabricated and ablations performed at 5-20 W for 15-120 s with the objective of creating ablations with a diameter/length aspect ratio of at least 0.9. The new dual-slot design at 8 GHz created significantly more spherical ablations than a commercial antenna at 2.45 GHz in ex vivo liver tissue (Average Aspect Ratio 0.8081 vs. 0.4532, p <;<; 0.05). In vivo studies confirmed the highly spherical results ex vivo. Initial testing shows that the dual-slot antenna and 8 GHz generator can be used to ablate tumors in mice.

  12. A simplified model for the viscous crossflow in a slotted test section

    NASA Astrophysics Data System (ADS)

    Cooke, C. H.

    1981-03-01

    A simplified physical model is constructed which simulates the viscous crossflow in a fluid layer near the slots at a fixed streamwise location in a slotted wind tunnel. For low to moderate Reynolds numbers, numerical solutions of the two-dimensional, incompressible Navier-Stokes equations in stream function and vorticity, which govern the model flow, are obtained. Fairly general slot geometry is incorporated by means of the Thompson-Thames-Mastin transformation. An approximate factorization scheme with cyclic acceleration parameters is employed to solve a finite difference analog of the stream function equation. The vorticity equation is numerically solved with a modified version of the classical alternating direction implicit (ADI) scheme. Although no quantitative assessment of solution accuracy can be made, numerical results for variations in incremental wall pressure around the slot are at least qualitatively similar to some experimental results of Berndt and Sorenson.

  13. Slotted surface coil with reduced g-factor for SENSE imaging.

    PubMed

    Ocegueda, K; Rodriguez, A O

    2006-01-01

    A new coil design inspired on the slot-and-hole magnetron tube is proposed for SENSE imaging. To investigate its g-factor behaviour: an SNR formula was derived using the quasi-static approach, and combined with the ultimate g-factor formula to compute the ultimate-factor-g-vs-depth plots. A g-factor expression was derived for the circular coil using the same approach for comparison purposes. SNR-vs-depth profiles of an 4-slot coil showed an important improvement over the circular coil. The 4-slot coil g-factor can be up to 58.32% lower than that of a single circular-shaped coil. This improvement makes the slotted surface coil a good choice for SENSE imaging.

  14. Effects of Anode Wettability and Slots on Anodic Bubble Behavior Using Transparent Aluminium Electrolytic Cells

    NASA Astrophysics Data System (ADS)

    Zhao, Zhibin; Gao, Bingliang; Feng, Yuqing; Huang, Yipeng; Wang, Zhaowen; Shi, Zhongning; Hu, Xianwei

    2017-02-01

    Transparent aluminum electrolytic cells were used to study the effects of anode wettability and slots on bubble behavior in a similar environment to that used in industrial cells. Observations were conducted using two types of transparent cells, one with side-observation and the other with a bottom-observation cell design. Anodic bubbles rising process in the side channel is strongly affected by the wettability of the anode. After rising a short distance, the bubbles detach from the anode vertical surface at good-wetting anode cases, while the bubbles still attach to the vertical surface at poor-wetting anode cases. Anode slots of width of 4 mm are able to prevent smaller bubbles from coalescing into larger bubbles and thus decrease the bubble size and gas coverage on the anode. Anode slots also make a contribution in slightly reducing bubble thickness. With the presence of slots, the bubble-induced cell voltage oscillation decreases as well.

  15. Long-Term Variations of the Electron Slot Region and Global Radiation Belt Structure

    NASA Technical Reports Server (NTRS)

    Fung, Shing F.; Shao, Xi; Tan, Lun C.

    2005-01-01

    We report the observations of changes of the nominal position of the quiet-time radiation belt slot over the solar cycles. It has been found that the slot region, believed to be a result of enhanced precipitation losses of energetic electrons due to their interactions with VLF waves in the magnetosphere, tends to shift to higher L (approximately 3) during a solar maximum compared to its canonical L value of approximately 2.5, which is more typical of a solar minimum. The solar-cycle migration of the slot can be understood in terms of the solar-cycle changes in ionospheric densities, which may cause the optimal wave-particle interaction region during higher solar activity periods to move to higher altitudes and higher latitudes, thus higher L. Our analysis also suggests that the primary wave-particle interaction processes that result in the slot formation are located off of the magnetic equator.

  16. Analysis of the characteristics of slot design affecting resistance to sliding during active archwire configurations

    PubMed Central

    2013-01-01

    Background During orthodontic treatment, a low resistance to slide (RS) is desirable when sliding mechanics are used. Many studies showed that several variables affect the RS at the bracket-wire interface; among these, the design of the bracket slot has not been deeply investigated yet. This study aimed to clarify the effect of different slot designs on the RS expressed by five types of low-friction brackets in vertical and horizontal active configurations of the wire. Methods Five low-friction brackets (Damon SL II, Ormco, Orange, CA, USA; In-Ovation, GAC International, Bohemia, NY, USA; Quick, Forestadent, Pforzheim, Germany; Time 2, AO, Sheboygan, WI, USA; Synergy, RMO, Denver, CO, USA) coupled with an 0.014-in NiTi thermal wire (Therma-Lite, AO) were tested in two three-bracket experimental models simulating vertical and horizontal bracket displacements. A custom-made machine was used to measure frictional resistance with tests repeated on ten occasions for each bracket-wire combination. Design characteristics such as the mesio-distal slot width, slot depth, and presence of chamfered edges at the extremities of the slot were evaluated on SEM images (SUPRA, Carl Zeiss, Oberkochen, Germany) and analyzed in relation to the data of RS recorded. Results Time 2 was found to show the higher frictional forces (1.50 and 1.35 N) in both experimental models (p < 0.05), while Quick and Synergy brackets showed the lower frictional values in the vertical (0.66 N) and in the horizontal (0.68 N) bracket displacements, respectively. With vertically displaced brackets, the increased mesio-distal slot width and the presence of clear angle at mesial and distal slot edges increase the values of RS. With brackets horizontally displaced, the RS expressed by the wire is influenced simultaneously by the depth of the slot, the mesio-distal slot width, and the presence of clear angle at the extremities of the slot base, the clip, or the slide. Conclusion In order to select the proper low

  17. Internal Maxillary Bypass for Complex Pediatric Aneurysms.

    PubMed

    Wang, Long; Lu, Shuaibin; Qian, Hai; Shi, Xiang'en

    2017-07-01

    Complex pediatric aneurysms (PAs) are an unusual clinicopathologic entity. Data regarding the use of a bypass procedure to treat complex PAs are limited. Internal maxillary artery-to-middle cerebral artery bypass with radial artery graft was used to isolate PAs. Bypass patency and aneurysm stability were evaluated using intraoperative Doppler ultrasound, indocyanine green videoangiography, and postoperative angiography. Modified Rankin Scale was used to assess neurologic function. Over a 5-year period, 7 pediatric patients (≤18 years old) were included in our analysis. Mean age of patients was 14.4 years (range, 12-18 years), and mean size of PAs was 23.6 mm (range, 9-37 mm). All cases manifested with complex characteristics. Proximal artery occlusion was performed in 3 cases, complete excision following aneurysmal distal internal maxillary artery bypass was performed in 2 cases, and combined proximal artery occlusion and aneurysm excision was performed in the 2 remaining cases. Mean intraoperative blood flow was 61.6 mL/minute (range, 40.0-90.8 mL/minute). Graft patency rate was 100% during postoperative recovery and at the last follow-up examination (mean, 20 months; range, 7-45 months). All patients had excellent outcomes except for 1 patient who died of multiple-organ failure. Internal maxillary artery bypass is an essential technique for treatment of selected cases of complex PAs. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Conformal Dielectric-Filled Edge-Slot Antennas for Bodies of Revolution

    DTIC Science & Technology

    1977-09-01

    surface of the body and, for certain applications, is better than cavity-backed slot, microstrip or patch antennas. A modified version of the antenna, a...involving bodies of revolution require directive beams at a prescribed angle relative to the axis of the body. This requirement can be met easily by...analytical study of the edge-slot antena ia currently underway,* but definitive results are not yet available. However, two empirical models, which explain

  19. High sensitivity liquid sensing by optimized slot photonic crystal ring resonator

    NASA Astrophysics Data System (ADS)

    Jannesari, R.; Grille, T.; Hedenig, U.; Jakoby, B.

    2017-05-01

    In this work we present a design to enhance absorption of infrared light by a fluid analyte being in contact with a slot photonic crystal ring resonator (slot-PCRR). For this purpose, we propose a new PCRR design facilitating higher interaction between guided mode and analyte. These types of PCRRs are based on two-dimensional photonic crystals, which consist of an array of holes in a silicon slab being arranged in a hexagonal lattice. The holes will be filled with liquid analyte. A slot is embedded in this hexagonal ring cavity to create a slot-PCRR. The strong confinement of light in the low index region, occupied by the analyte, is the key advantage of the slot- PCRR. We also calculate the relative intensity change in the transmission spectrum due to the absorption in the analyte. The maximum change obtained is given by a mode which has most of the electromagnetic field energy in the region the region filled with the analyte. Furthermore, this mode is well separated from neighboring bands, which has the advantage that impinging light with specified frequency is less likely to spuriously couple to other modes with the same frequency, which would decrease the amount of energy coupled to desired mode. The slot-PCRR yields a higher relative change due to absorption compared to the PCRR without a slot. In this work, the radii of six rods at the outer PhC were tuned to enhance the quality factor of slot-PCRR. Using these optimum values of radii, the Q-factor rises up to 80000.

  20. Transverse excitation of plasmonic slot nano-resonators embedded in metal-coated plasmonic microfiber tips

    NASA Astrophysics Data System (ADS)

    Ding, M.; Zervas, M. N.; Brambilla, G.

    2013-04-01

    A plasmonic slot rectangular nano-resonator embedded in a metal-coated optical microfiber tip is theoretically and experimentally demonstrated. In this device, light is transversely coupled from the optical microfiber tip into the plasmonic slot nano-resonator, showing strong localization in three dimensions and strong enhancement factor (7.24 × 103). This device can find wide range of applications such as surface enhanced Raman scattering, optical filtering, spectroscopy, and bio-sensing.

  1. Further Flight Tests on the Effectiveness of Handley Page Automatic Control Slots

    NASA Technical Reports Server (NTRS)

    Pleines, Wilhelm

    1932-01-01

    Investigation of damping in roll within range of maximum lift with the Albatross L 75, with and without Handley Page automatic control slots, revealed the following: Without control slots, any attempt to go beyond a certain angle of attack near c(sub a max) in glide and climb, is followed by sudden sideslip. The conduct of the airplane throughout the motions in roll, moreover, confirmed that all attempts to higher angles of attack are accompanied by sudden loss of damping in roll.

  2. Upright Biplanar Slot Scanning in Pediatric Orthopedics: Applications, Advantages, and Artifacts.

    PubMed

    Hull, Nathan C; Binkovitz, Larry A; Schueler, Beth A; Kolbe, Amy B; Larson, A Noelle

    2015-07-01

    Digital slot scanning is a relatively new technology that has been used for imaging of pediatric orthopedic conditions such as scoliosis and leg-length discrepancies. This article will review the clinical applications, advantages, and unique artifacts of this new technology. Upright biplanar slot scanners acquire high-resolution radiographs simultaneously in two orthogonal planes with reduced radiation dose. Other advantages include a more physiologic weightbearing imaging position, improved Cobb angle measurements, and 3D modeling.

  3. Texture Fish

    ERIC Educational Resources Information Center

    Stone, Julie

    2007-01-01

    In an effort to provide an opportunity for her first graders to explore texture through an engaging subject, the author developed a three-part lesson that features fish in a mixed-media artwork: (1) Exploring Textured Paint; (2) Creating the Fish; and (3) Role Playing. In this lesson, students effectively explore texture through painting, drawing,…

  4. Texture Fish

    ERIC Educational Resources Information Center

    Stone, Julie

    2007-01-01

    In an effort to provide an opportunity for her first graders to explore texture through an engaging subject, the author developed a three-part lesson that features fish in a mixed-media artwork: (1) Exploring Textured Paint; (2) Creating the Fish; and (3) Role Playing. In this lesson, students effectively explore texture through painting, drawing,…

  5. Wind tunnel force and pressure tests of a 21% thick general aviation airfoil with 20% aileron, 25% slotted flap and 10% slot-lip spoiler

    NASA Technical Reports Server (NTRS)

    Wentz, W. H., Jr.; Fiscko, K. A.

    1979-01-01

    Force and surface pressure distributions were measured for the 21% LS(1)-0421 modified airfoil fitted with 20% aileron, 25% slotted flap and 10% slot lip spoiler. All tests were conducted at a Reynolds number of 2.2 x 10 to the 6th power and a Mach number of 0.13. The lift, drag, pitching moments, control surface normal force and hinge moments, and surface pressure distributions are included in the results. Incremental performance of flap and aileron are discussed and compared to the GA(W)-2 airfoil. Spoiler control which shows a slight reversal tendency at high alpha, is examined.

  6. Yakima River Basin Phase II Fish Screen Evaluations, 2002

    SciTech Connect

    Carter, Jessica A.; McMichael, Geoffrey A.; Chamness, Mickie A.

    2003-03-01

    In 2002, the Pacific Northwest National Laboratory evaluated 23 Phase II fish screen sites in the Yakima River Basin as part of a multi-year project for the Bonneville Power Administration on the effectiveness of fish screening devices. Pacific Northwest National Laboratory collected data to determine whether velocities in front of the screens and in the bypasses met National Marine Fisheries Service criteria to promote safe and timely fish passage and whether bypass outfall conditions allowed fish to safely return to the river. In addition, Pacific Northwest National Laboratory conducted underwater video surveys to evaluate the environmental and operational conditions of the screen sites with respect to fish passage. Based on evaluations in 2002, PNNL concluded that: (1) In general, water velocity conditions at the screen sites met fish passage criteria set by the National Marine Fisheries Service. (2) Conditions at most facilities would be expected to provide for safe juvenile fish passage. (3) Conditions at some facilities indicate that operation and/or maintenance should be modified to increase safe juvenile fish passage. (4) Automated cleaning brushes generally functioned properly; chains and other moving parts were typically well greased and operative. (5) Removal of sediment buildup and accumulated leafy and woody debris should be improved at some sites.

  7. Evaluation of a thin-slot formalism for finite-difference time-domain electromagnetics codes

    SciTech Connect

    Turner, C.D.; Bacon, L.D.

    1987-03-01

    A thin-slot formalism for use with finite-difference time-domain (FDTD) electromagnetics codes has been evaluated in both two and three dimensions. This formalism allows narrow slots to be modeled in the wall of a scatterer without reducing the space grid size to the gap width. In two dimensions, the evaluation involves the calculation of the total fields near two infinitesimally thin coplanar strips separated by a gap. A method-of-moments (MoM) solution of the same problem is used as a benchmark for comparison. Results in two dimensions show that up to 10% error can be expected in total electric and magnetic fields both near (lambda/40) and far (1 lambda) from the slot. In three dimensions, the evaluation is similar. The finite-length slot is placed in a finite plate and an MoM surface patch solution is used for the benchmark. These results, although less extensive than those in two dimensions, show that slightly larger errors can be expected. Considering the approximations made near the slot in incorporating the formalism, the results are very promising. Possibilities also exist for applying this formalism to walls of arbitrary thickness and to other types of slots, such as overlapping joints. 11 refs., 25 figs., 6 tabs.

  8. Analysis of light propagation in slotted resonator based systems via coupled-mode theory.

    PubMed

    Hiremath, Kirankumar R; Niegemann, Jens; Busch, Kurt

    2011-04-25

    Optical devices with a slot configuration offer the distinct feature of strong electric field confinement in a low refractive index region and are, therefore, of considerable interest in many applications. In this work we investigate light propagation in a waveguide-resonator system where the resonators consist of slotted ring cavities. Owing to the presence of curved material interfaces and the vastly different length scales associated with the sub-wavelength sized slots and the waveguide-resonator coupling regions on the one hand, and the spatial extent of the ring on the other hand, this prototypical system provides significant challenges to both direct numerical solvers and semi-analytical approaches. We address these difficulties by modeling the slot resonators via a frequency-domain spatial Coupled-Mode Theory (CMT) approach, and compare its results with a Discontinuous Galerkin Time-Domain (DGTD) solver that is equipped with curvilinear finite elements. In particular, the CMT model is built on the underlying physical properties of the slotted resonators, and turns out to be quite efficient for analyzing the device characteristics. We also discuss the advantages and limitations of the CMT approach by comparing the results with the numerically exact solutions obtained by the DGTD solver. Besides providing considerable physical insight, the CMT model thus forms a convenient basis for the efficient analysis of more complex systems with slotted resonators such as entire arrays of waveguide-coupled resonators and systems with strongly nonlinear optical properties.

  9. Thin cylindrical slot in an optical microdisk cavity for sensing biomaterials

    NASA Astrophysics Data System (ADS)

    Daraei, Ahmadreza; Daraei, Mohammad Esmaeil

    2017-04-01

    In this paper, we propose and investigate a thin cylindrical slot etched into a disk shape optical microcavity (MC) aiming for sensing biomaterials in a label-free style. Supporting whispering gallery modes (WGMs), with remarkably large quality factor to modal volume ratio (Q/Vm) of the optical MC structures that penetrate in the slot region, enables us to perform sensing. Three different geometries for the side walls of host microdisk cavities, including vertical, 60° wedged, and half-circular cross section, are selected for investigations. In each individual case, the radial position, width, and height of the thin cylindrical slot are varied. The electromagnetic (EM) field intensity distributions (mode mapping profiles) of the WGMs show funneling of the intensified fields into the slot area that possessing nearly the same high Q values. Tuning the slot position, width, and depth for a suitably chosen WGM, sensing could be optimized for different biomaterials. Sensitivity value as high as 75 nm/RIU is calculated for the half-circular side wall microdisk. The proposed WGM-based slotted microdisk, as a state-of-the-art device which can operate, such as lab-on-chip structure, would function as a sensitive biosensor, even down to the single biomolecule levels.

  10. Slotted cage resonator for high-field magnetic resonance imaging of rodents

    NASA Astrophysics Data System (ADS)

    Marrufo, O.; Vasquez, F.; Solis, S. E.; Rodriguez, A. O.

    2011-04-01

    A variation of the high-frequency cavity resonator coil was experimentally developed according to the theoretical frame proposed by Mansfield in 1990. Circular slots were used instead of cavities to form the coil endplates and it was called the slotted cage resonator coil. The theoretical principles were validated via a coil equivalent circuit and also experimentally with a coil prototype. The radio frequency magnetic field, B1, produced by several coil configurations was numerically simulated using the finite-element approach to investigate their performances. A transceiver coil, 8 cm long and 7.6 cm in diameter, and composed of 4 circular slots with a 15 mm diameter on both endplates, was built to operate at 300 MHz and quadrature driven. Experimental results obtained with the slotted cage resonator coil were presented and showed very good agreement with the theoretical expectations for the resonant frequency as a function of the coil dimensions and slots. A standard birdcage coil was also built for performance comparison purposes. Phantom images were then acquired to compute the signal-to-noise ratio of both coils showing an important improvement of the slotted cage coil over the birdcage coil. The whole-body images of the mouse were also obtained showing high-quality images. Volume resonator coils can be reliably built following the physical principles of the cavity resonator design for high-field magnetic resonance imaging applications of rodents.

  11. Computational Analysis of Forebody Tangential Slot Blowing on the F/A-18

    NASA Technical Reports Server (NTRS)

    Gee, Ken; Rizk, Yehia M.; Schiff, Lewis B.; Kutler, Paul (Technical Monitor)

    1994-01-01

    An overview of the computational effort to analyze forebody tangential slot blowing for use on the F/A-18 aircraft is presented. Tangential slot blowing generates side force and yawing moment which may be used to control the aircraft flying at high angle of attack. Computations using the isolated forebody are obtained at full-scale wind tunnel test conditions for direct comparison with available experimental data. The effects of jet exit conditions, jet length, and jet location are also studied using the isolated forebody. In addition, these computations are used to predict the effect of slot blowing at transonic maneuvering flight conditions. The effects of over- and under-blowing on force and moment production are analyzed. Non-time-accurate solutions are obtained to determine the steady-state side force and yawing moments generated by tangential slot blowing. Time-accurate solutions are obtained to study the force onset time lag of tangential slot blowing. The effect of blowing on the burst point location are then analyzed by obtaining computations using the aircraft geometry, which includes the wing, empennage, and faired-over inlets. The effect of blowing on the buffet loads on the vertical tails are analyzed using time-accurate computations. Comparison with available experimental data from full-scale wind tunnel and sub-scale wind tunnel tests are made. This computational analysis compliments the experimental results and provides a detailed understanding of the effects of tangential slot blowing on the flow field about the F/A-18.

  12. Effect of U-Slot Length Variations on the Performance of Stacked Microstrip Antenna

    NASA Astrophysics Data System (ADS)

    Yadahalli, Ravi M.; Usha, K. K.; Ayachit, N. H.; Vani, R. M.; Fatima, Sara F.; Hunagund, P. V.

    2007-07-01

    Antenna miniaturization plays an important role in the design of modern personal wireless systems. Several minimization techniques have been known for a long time. The mail minimization tools are loading the antenna with lumped elements, high permittivity dielectric materials or conducting additions; using a ground plane with short circuits and optimizing the geometry. In this paper, a compact stacked microstrip antenna with loaded U-slot on the driven (lower) patch and probe feed structure is proposed. The purpose of this paper is to study the variations of a U-slot length with the parameters of stacked microstrip antenna such as input impedance, bandwidth and resonant frequency etc. The paper emphasizes the significant change observed in the performance of compact stacked microstrip antenna. Earlier work has utilized a U-slot on the planar microstrip antenna and the effect of slot width on performance of microstrip antenna is studied. The software package IE3D® version 11.5 was used to simulate the antenna structures. The simulation results show that, the size reduction is achieved by inserting U-slot in the radiating element. Further, it is observed from the simulation that maximum overall impedance bandwidth is achieved for width of U-slot LS = 22 mm, which is 277.78 MHz. This developed microstrip antenna is small enough to be easily accommodated in wireless applications.

  13. Slow light in dual-periodic photonic crystals based slotted-waveguide coupled cavity

    NASA Astrophysics Data System (ADS)

    Zhu, Na; Li, Yuanyuan; Chen, Cheng; Yan, Shu

    2016-09-01

    Considering the capacity of the nanoscale width area with the low-refractive index can confine light waves, the dual-periodic slotted photonic crystals, which is constructed by coupling low-refractive index's slotted-waveguide with high-refractive index's cavity is proposed in this paper. The best slow light properties and the optimal slotted-waveguide coupled cavity are achieved by adjusting the slotted-width and the period of cavity respectively. In this structure, the slow-light properties are simulated by Plane Wave Expansion (PWE), the result reveals that the group velocities are all three orders of magnitude smaller than the speed of light in vacuum, the slowest value is 7.96 ×10-4 c when the slotted-width is 0.54a and the period of cavity is 0.95a. Moreover, the corresponding Normalized Delay-Bandwidth Product (NDBP) values are larger than 0.24. Besides, the slotted-waveguide coupled cavity can be reconfigured, which accordingly changes the corresponding slow-light property. At last, the numerical results provide a new thought and method for decreasing group velocity and potential application for optical buffer in photonic crystals field.

  14. Low-loss hybrid plasmonic waveguide with double low-index nano-slots.

    PubMed

    Dai, Daoxin; He, Sailing

    2010-08-16

    A hybrid plasmonic waveguide with double low-index nano-slots is introduced. The fabrication is simple and compatible with the standard processes for SOI wafers. The theoretical investigation shows that the present hybrid plasmonic waveguide has a low loss and consequently a relatively long propagation distance (at the order of several tens of lambda). For TE polarization, there is a strong field enhancement in the double nano-slots. More power is confined in the low-index nano-slots for a smaller core width. For a 50 nm-wide hybrid plasmonic waveguide with double 10 nm-wide slots, the power confinement factor in the nano-slots is as high as 85% and the effective area is as small as 0.007 microm(2) at 1550 nm. Consequently, the power density in the nano-slots becomes very high, e.g., >120 microm(-2), which is very desired for many applications. For the present hybrid plasmonic waveguide, the lateral dimension could be less than 50 nm and the calculated decoupled separation for two parallel identical waveguides is only 0.62 microm, which is helpful to realize photonic integration circuits with ultra-high integration density.

  15. Three-dimensional imaging of intracochlear tissue by scanning laser optical tomography (SLOT)

    NASA Astrophysics Data System (ADS)

    Tinne, N.; Nolte, L.; Antonopoulos, G. C.; Schulze, J.; Andrade, J.; Heisterkamp, A.; Meyer, H.; Warnecke, A.; Majdani, O.; Ripken, T.

    2016-02-01

    The presented study focuses on the application of scanning laser optical tomography (SLOT) for non-destructive visualization of anatomical structures inside the human cochlea ex vivo. SLOT is a laser-based highly efficient microscopy technique, which allows for tomographic imaging of the internal structure of transparent large-scale specimens (up to 1 cm3). Thus, in the field of otology this technique is best convenient for an ex vivo study of the inner ear anatomy. For this purpose, the preparation before imaging comprises mechanically assisted decalcification, dehydration as well as optical clearing of the cochlea samples. Here, we demonstrate results of SLOT visualizing hard and soft tissue structures of the human cochlea with an optical resolution in the micrometer range using absorption and autofluorescence as contrast mechanisms. Furthermore, we compare our results with the method of X-ray micro tomography (micro-CT, μCT) as clinical gold standard which is based only on absorption. In general, SLOT can provide the advantage of covering all contrast mechanisms known from other light microscopy techniques, such as fluorescence or scattering. For this reason, a protocol for antibody staining has been developed, which additionally enables selective mapping of cellular structures within the cochlea. Thus, we present results of SLOT imaging rodent cochleae showing specific anatomical structures such as hair cells and neurofilament via fluorescence. In conclusion, the presented study has shown that SLOT is an ideally suited tool in the field of otology for in toto visualization of the inner ear microstructure.

  16. Experimental Investigation of By-pass Transition

    NASA Astrophysics Data System (ADS)

    Sengupta, Tapan; Lim, T. T.; Chattopadhyay, Manojit

    2000-11-01

    By-pass transition, a phenomenon often encountered in nature and engineering devices, is a complex flow instability caused by moving disturbances over bodies. To date this phenomenon is not fully explained. In the present research a controlled experiment is performed to show that the violent breakdown during by-pass transition is dominated by a two-dimensional mechanism and the resultant broadband energy spectrum of the corresponding turbulent flow is excited at the receptivity stage itself by the primary instability. The experiment is conducted in a water tunnel using dye visualisation technique, and the by-pass transition is created by controlled motion of captive vortices. In the presentation, apart from showing video images of the phenomenon, the similarity of the observed events with secondary instability and fully developed turbulent flows will be discussed.

  17. Queueing models for token and slotted ring networks. Thesis

    NASA Technical Reports Server (NTRS)

    Peden, Jeffery H.

    1990-01-01

    Currently the end-to-end delay characteristics of very high speed local area networks are not well understood. The transmission speed of computer networks is increasing, and local area networks especially are finding increasing use in real time systems. Ring networks operation is generally well understood for both token rings and slotted rings. There is, however, a severe lack of queueing models for high layer operation. There are several factors which contribute to the processing delay of a packet, as opposed to the transmission delay, e.g., packet priority, its length, the user load, the processor load, the use of priority preemption, the use of preemption at packet reception, the number of processors, the number of protocol processing layers, the speed of each processor, and queue length limitations. Currently existing medium access queueing models are extended by adding modeling techniques which will handle exhaustive limited service both with and without priority traffic, and modeling capabilities are extended into the upper layers of the OSI model. Some of the model are parameterized solution methods, since it is shown that certain models do not exist as parameterized solutions, but rather as solution methods.

  18. Spiral vortex formation in cross-slot flow

    NASA Astrophysics Data System (ADS)

    Haward, Simon; Burshtein, Noa; Poole, Robert; Oliveira, Paulo; Alves, Manuel; Shen, Amy

    2016-11-01

    Fluid flow through bisecting channels (cross-slots) results in the formation of a steady spiral vortex as the Reynolds number (Re) is increased above a modest critical value (Rec) . The value of Rec is strongly dependent on the channel aspect ratio, α = d / w , where d and w are the depth and width of the channel, respectively. Quasistatic experiments and numerical simulations over a range of Re show that for low α this symmetry-breaking bifurcation is supercritical, however subcritical behavior develops as α is increased. The system can be described by a Landau-type 6th-order polynomial potential and we identify a value of α 0 . 55 for which a tricritical point can be found. Dynamic experiments and simulations conducted across the transition indicate a plausible mechanism for the onset of the instability. Our analysis suggests that the transition results from the growth of center-point vorticity induced by random imbalances between two pairs of Dean vortices that form in the channel cross-section. Vorticity growth is governed by two distinct time scales. At short times, viscous diffusion dominates and vorticity grows slowly. Once the vorticity is sufficiently high, vortex stretching dominates and the vorticity grows rapidly until steady state is reached.

  19. Turbulence Studies of a Rectangular Slotted Noise-Suppressor Nozzle

    NASA Technical Reports Server (NTRS)

    Laurence, James C.

    1960-01-01

    The problem of noise suppression of turbojet engines has shown a need for turbulence data within the flow field of various types of nozzles used in ad hoc investigations of the sound power. The result of turbulence studies in a nozzle configuration of four parallel rectangular slots is presented in this report with special attention to the effect of the spacing of the nozzles on the intensity of turbulence, scale of turbulence, spectrum of turbulence, and the mean stream velocity. Taylor's hypothesis, which describes the convection of the turbulence eddies, was tested and found correct within experimental error and certain experimental and theoretical limitations. The convection of the pressure patterns was also investigated, and the value of the convection velocity was found to be about 0.43 times the central core velocity of the jets. The effect of the spacing-to-width ratio of the nozzles upon the turbulence intensity, the scale of turbulence, and the spectral distribution of the noise was found in general to produce a maximum change for spacing-to-width ratios of 1.5 to 2.0. These changes may be the cause of the reduction in sound power reported for similar full-scale nozzles and test conditions under actual (static) engine operation. A noise reduction parameter is defined from Lighthill's theory which gives qualitative agreement with experiments which show the noise reduction is greatest for spacing-to-width ratios of 1.5 to 2.0.

  20. Variable Star Signature Classification using Slotted Symbolic Markov Modeling

    NASA Astrophysics Data System (ADS)

    Johnston, Kyle B.; Peter, Adrian M.

    2016-01-01

    With the advent of digital astronomy, new benefits and new challenges have been presented to the modern day astronomer. No longer can the astronomer rely on manual processing, instead the profession as a whole has begun to adopt more advanced computational means. Our research focuses on the construction and application of a novel time-domain signature extraction methodology and the development of a supporting supervised pattern classification algorithm for the identification of variable stars. A methodology for the reduction of stellar variable observations (time-domain data) into a novel feature space representation is introduced. The methodology presented will be referred to as Slotted Symbolic Markov Modeling (SSMM) and has a number of advantages which will be demonstrated to be beneficial; specifically to the supervised classification of stellar variables. It will be shown that the methodology outperformed a baseline standard methodology on a standardized set of stellar light curve data. The performance on a set of data derived from the LINEAR dataset will also be shown.