Science.gov

Sample records for slot fish bypass

  1. 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).

  2. 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.

  3. 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.

  4. 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).

  5. 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.

  6. Hydraulic model evaluation of the Eicher passive pressure screen fish bypass system: Final report

    SciTech Connect

    Wert, M.A.

    1987-10-01

    A hydraulic model of a passive pressure screen fish bypass system was evaluated at the University of Washington Harris Hydraulics Laboratory, Seattle, during 1984 and 1985. Stainless steel wedgewire screen inclined at 10.5, 16.5 or 30 degrees to horizontal, was tested in a Plexiglas conduit. Velocity profiles were measured by pitot tube traverses. Dye tracers were also released to visually track the streamline patterns. Fish were monitored by video camera and recorder as they passed through the pressurized model. The screen angles, water velocities and screen types were varied. Scale loss was evaluated for smolted fish contacting the screen. Species tested included rainbow trout (Salmo gairdneri) and smolts of coho salmon (Oncorhynchus kisutch), chinook salmon (O. tshawystcha) and steelhead trout (S. gairdneri). Scale loss did not occur to coho, chinook or steelhead smolts which contacted the screen. No delayed mortality was observed within 72 hours after testing. All fish were successfully passed when velocities through the model were maintained at greater than 5 feet (1.5 m) per second. Small fish (fry size) passed through the model more swiftly than larger ones. Rainbow trout were used for impingement tests over a range of test section velocities from 3.0 feet (0.9 m) to 10 feet (3 m) per second. Impingement was predictably produced or avoided by manipulation of velocities, and was most prevalent at test section velocities under 4 feet (1.2 m) per second. Variations in the velocity vector perpendicular to the screen did not affect fish passage over the range tested of 0.4 to 3.0 feet (0.1 to 0.9 m) per second.

  7. 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.

  8. 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

  9. 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.

  10. Sloppy-slotted ALOHA

    NASA Technical Reports Server (NTRS)

    Crozier, Stewart N.

    1990-01-01

    Random access signaling, which allows slotted packets to spill over into adjacent slots, is investigated. It is shown that sloppy-slotted ALOHA can always provide higher throughput than conventional slotted ALOHA. The degree of improvement depends on the timing error distribution. Throughput performance is presented for Gaussian timing error distributions, modified to include timing error corrections. A general channel capacity lower bound, independent of the specific timing error distribution, is also presented.

  11. Mercury cycling in agricultural and non-agricultural wetlands in the Yolo Bypass Wildlife Area, California: bioaccumulation in small fish

    NASA Astrophysics Data System (ADS)

    Ackerman, J. T.; Eagles-Smith, C. A.; Miles, K. A.; Ricca, M. A.

    2007-12-01

    We examined the bioaccumulation of mercury in small fish within white rice, wild rice, and permanent wetland habitats at the Yolo Wildlife Area during the 2007 rice growing season. We introduced 30 mosquito fish in each of four cages placed at the inlet, center, and outlet (two cages) of each wetland in June, immediately after the white rice fields were re-flooded after being seeded. All fish were removed from their cages 60-days after their introduction, with the exception that ten fish from each of the second cages at the outlets were removed 30-days after introduction to assess temporal trends in mercury exposure. Mercury concentrations will be compared between fish that were introduced into cages and reference fish that originated from the same fish stock (Sacramento County Vector Control). We also measured fish length and mass both when they were introduced and collected to 1) control for growth effects on mercury bioaccumulation and 2) examine whether wetland habitat influenced growth rates. Fish are currently being analyzed for mercury and results will be available by the conference.

  12. Detail of gate, gate slots, and connection between the two ...

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

    Detail of gate, gate slots, and connection between the two segments of the rectangular rearing tank. Pump house (1962) at entrance is in the background. View to the southwest. - Prairie Creek Fish Hatchery, Hwy. 101, Orick, Humboldt County, CA

  13. 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).

  14. 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

  15. Multichannel time-slot permuters

    NASA Astrophysics Data System (ADS)

    Jordan, Harry F.; Lee, Kyungsook Y.; Lee, Daeshik

    1993-02-01

    We consider the general switching problem known as time-space-time domain permutations in telecommunications. We present a new set of multichannel time slot permuters for L parallel frames of M time slots (L equals 2l, M equals 2m). The multichannel time slot permuters are obtained by combining L X L spatial networks and time slot permuters for a frame of M time slots. In this paper, the Benes network, the Batcher sorter and the Lambda network for spatial networks, and their counterparts, the RJS time slot permuter, the S time slot sorter, and the Lambda time slot permuter are considered.

  16. 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.

  17. 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).

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Slotted photonic crystal sensors.

    PubMed

    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

  8. Slotted variable camber flap

    NASA Technical Reports Server (NTRS)

    Andrews, D. G. (Inventor)

    1984-01-01

    Variable camber actuator assemblies broaden the range of speeds at which lift to drag performance is maximized for slotted flap wings. Lift is improved over a broader range of cruising speeds by varying wing camber with rotational flap movements that do not introduce wing slots and induced drag. Forward flaps are secured to forward flange links which extended from, and are a part of forward flap linkage assemblies. The forward flaps rotate about flap pivots with their rotational displacement controlled by variable camber actuator assemblies located between the forward flaps and the forward flange links. Rear flaps are held relative to the forward flaps by rear flap linkage assemblies which may act independently from the forward flap linkage assemblies and the variable camber actuator assemblies. Wing camber is varied by rotating the flaps with the variable camber actuator assemblies while the flaps are in a deployed or tucked position. Rotating the flaps in a tucked position does not introduce significant wing surface discontinuities, and reduces aircraft fuel consumption on most flight profiles.

  9. 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

  10. 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.

  11. Spiral slotted phased antenna array

    NASA Technical Reports Server (NTRS)

    Ellis, H., Jr. (Inventor)

    1982-01-01

    A flush mounting, cavity-backed, dual orthogonal slot antenna for aircraft and space vehicles is described. Improved radiation pattern characteristics are obtained by making the spiral slot pattern elliptical in the aperture plane. A cavity and a flanged aperture plate are configured such that one slot pair is orthogonal with respect to another slot pair within the aperture plate. Coaxial split-tube baluns are used to drive the junctions between corresponding slot pairs. An optional cavity dielectric is provided and a drive coupling arrangement includes a four port comparator hybrid having sum and difference ports respectively, for alternate excitation to produce a single lobe or a double lobe pattern with null. Switching apparatus is provided to connect a common terminal to either of the ports.

  12. Heart bypass surgery

    MedlinePlus

    Heart bypass surgery creates a new route, called a bypass, for blood and oxygen to go around a blockage to reach your heart. ... heart is still beating. This is called off-pump coronary artery bypass, or OPCAB. To create the bypass graft: The doctor will take a ...

  13. 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.

  14. 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.

  15. The Channel Acquisition Slot Protocol

    NASA Astrophysics Data System (ADS)

    Milian, Arturo Valencia; Tamura, Shinsuke; Yanase, Tatsuro

    This paper discusses the Channel Acquisition Slot Protocol (CASP), a new protocol for the Media Access Control (MAC) of wireless networks. The CASP is intended to provide a more efficient use of communication channels; this is achieved by mechanisms for eliminating contentions among network stations and by an implicit handling of acknowledge messages. To avoid collisions of messages, the protocol divides the time into short slots, each of which is assigned to a single station, and any station must wait its own slot to start its transmission. However once a transmission is started the slot can be extended and no other station can make use of the channel. The use of an implicit acknowledge mechanism removes the necessity of an acknowledge message exchange for every transmission. In various simulated scenarios the CASP shows a 25% better throughput efficiency compared with the one of the IEEE802.11 protocol.

  16. Coronary Artery Bypass Surgery

    MedlinePlus

    ... t help, you may need coronary artery bypass surgery. The surgery creates a new path for blood to flow ... more than one bypass. The results of the surgery usually are excellent. Many people remain symptom-free ...

  17. Coronary Artery Bypass

    MedlinePlus

    ... to 3 days in the Intensive Care Unit (ICU). Life After Bypass After bypass surgery, your doctor will recommend that you join a cardiac rehabilitation program. These programs help you make lifestyle changes ...

  18. Build a circularly polarized waveguide slot antenna

    NASA Astrophysics Data System (ADS)

    Kisliuk, M.; Axelrod, A.

    1987-06-01

    The development and design of a circularly polarized waveguide slot antenna are described. Consideration is given to the resonance frequency, radiation efficiencies, excitement, and resonant conductance of the transverse and longitudinal slots. The transverse and longitudinal slots in a rectangular guide are analyzed. The voltage distribution across the slot is calculated from the solution of a standard transmission line equation; and using the Poynting theorem the fields scattered by the slot in an arbitrary frequency range are determined. The proposed antenna is examined using an equivalent circuit; a diagram of the circuit is given. The radiation, slot, and antenna efficiencies are measured.

  19. Field distortion in a longitudinal slot radiator in a slotted-waveguide array

    NASA Astrophysics Data System (ADS)

    Wang, Hanyang; Sangster, A. J.

    1992-12-01

    A comprehensive solution to the tangential field distribution within a longitudinal slot in the presence of its neighboring slots in a linear slotted-waveguide array is presented which is based on the direct method of moments. A set of basic functions is used to simulate the field in the slots as a group. It is concluded that the mutual coupling has little impact on the shape of the field even when the interfering slots are asymmetrically distributed in relation to the slot under consideration. However, it significantly affects the amplitude of the slot aperture field.

  20. 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. PMID:25827177

  1. Slot Region Radiation Environment Models

    NASA Astrophysics Data System (ADS)

    Sandberg, Ingmar; Daglis, Ioannis; Heynderickx, Daniel; Evans, Hugh; Nieminen, Petteri

    2013-04-01

    Herein we present the main characteristics and first results of the Slot Region Radiation Environment Models (SRREMs) project. The statistical models developed in SRREMs aim to address the variability of trapped electron and proton fluxes in the region between the inner and the outer electron radiation belt. The energetic charged particle fluxes in the slot region are highly dynamic and are known to vary by several orders of magnitude on both short and long timescales. During quiet times, the particle fluxes are much lower than those found at the peak of the inner and outer belts and the region is considered benign. During geospace magnetic storms, though, this region can fill with energetic particles as the peak of the outer belt is pushed Earthwards and the fluxes can increase drastically. There has been a renewed interest in the potential operation of commercial satellites in orbits that are at least partially contained within the Slot Region. Hence, there is a need to improve the current radiation belt models, most of which do not model the extreme variability of the slot region and instead provide long-term averages between the better-known low and medium Earth orbits (LEO and MEO). The statistical models developed in the SRREMs project are based on the analysis of a large volume of available data and on the construction of a virtual database of slot region particle fluxes. The analysis that we have followed retains the long-term temporal, spatial and spectral variations in electron and proton fluxes as well as the short-term enhancement events at altitudes and inclinations relevant for satellites in the slot region. A large number of datasets have been used for the construction, evaluation and inter-calibration of the SRREMs virtual dataset. Special emphasis has been given on the use and analysis of ESA Standard Radiation Environment Monitor (SREM) data from the units on-board PROBA-1, INTEGRAL, and GIOVE-B due to the sufficient spatial and long temporal

  2. Clogging the enrichment bypass

    SciTech Connect

    1995-05-01

    The issue that has come to be known as the bypass is the latest dispute in the continuing saga of uranium trade between the United States and the Commonwealth of Indepenent States. Bypass deals now being conducted by US utilities have drawn heavy criticism from the US Department of Commerce but are perfectly legal under the terms of the Suspension Agreements. Urged on by the United States Enrichment Corporation, the US DOC intends to stop, or at least severely restrict, bypass deals. Using a recent agreement with Kazakhstan as a case study, this article reviews the implications of such bypass deals.

  3. 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.

  4. Laparoscopic Revision of Jejunoileal Bypass to Gastric Bypass

    ClinicalTrials.gov

    2009-12-28

    Clinically Severe Obesity; Metabolic Complications After Jejunoileal Bypass; Nutritional Complications After Jejunoileal Bypass; Obesity Recidivism; Inadequate Initial Weight Loss; Intestinal Malabsorptive Syndrome; Protein Malnutrition

  5. Flood Bypass Capacity Optimization

    NASA Astrophysics Data System (ADS)

    Siclari, A.; Hui, R.; Lund, J. R.

    2015-12-01

    Large river flows can damage adjacent flood-prone areas, by exceeding river channel and levee capacities. Particularly large floods are difficult to contain in leveed river banks alone. Flood bypasses often can efficiently reduce flood risks, where excess river flow is diverted over a weir to bypasses, that incur much less damage and cost. Additional benefits of bypasses include ecosystem protection, agriculture, groundwater recharge and recreation. Constructing or expanding an existing bypass costs in land purchase easements, and levee setbacks. Accounting for such benefits and costs, this study develops a simple mathematical model for optimizing flood bypass capacity using benefit-cost and risk analysis. Application to the Yolo Bypass, an existing bypass along the Sacramento River in California, estimates optimal capacity that economically reduces flood damage and increases various benefits, especially for agriculture. Land availability is likely to limit bypass expansion. Compensation for landowners could relax such limitations. Other economic values could affect the optimal results, which are shown by sensitivity analysis on major parameters. By including land geography into the model, location of promising capacity expansions can be identified.

  6. 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 ...

  7. 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.

  8. Vertical slot fishways: Mathematical modeling and optimal management

    NASA Astrophysics Data System (ADS)

    Alvarez-Vázquez, L. J.; Martínez, A.; Vázquez-Méndez, M. E.; Vilar, M. A.

    2008-09-01

    Fishways are the main type of hydraulic devices currently used to facilitate migration of fish past obstructions (dams, waterfalls, rapids,...) in rivers. In this paper we present a mathematical formulation of an optimal control problem related to the optimal management of a vertical slot fishway, where the state system is given by the shallow water equations, the control is the flux of inflow water, and the cost function reflects the need of rest areas for fish and of a water velocity suitable for fish leaping and swimming capabilities. We give a first-order optimality condition for characterizing the optimal solutions of this problem. From a numerical point of view, we use a characteristic-Galerkin method for solving the shallow water equations, and we use an optimization algorithm for the computation of the optimal control. Finally, we present numerical results obtained for the realistic case of a standard nine pools fishway.

  9. 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.

  10. A slotted waveguide antenna with adjustable polarisation

    NASA Astrophysics Data System (ADS)

    Blommendaal, R.; Westerman, B. E.

    A new slotted waveguide antenna has been developed which has adjustable polarization, as well as good control of azimuth patterns, a light weight, and low windage. The design of the antenna is based on three slotted waveguides in a symmetrical configuration, which generate two orthogonal polarizations in a parallel plate region. Two arrays with matched inclined/displaced slots are used for the transverse polarization, while one array with matched edge slots is used for the longitudinal polarization. A corrugated horn is used to obtain equal vertical patterns. A prototype antenna with a 0.5 deg beamwidth and a weight of about 100 kg is presently under construction.

  11. Heart bypass surgery

    MedlinePlus Videos and Cool Tools

    ... of this great vein will be used to bypass the blocked arteries in the heart. The venous graft is sewn to the aorta and to the affected coronary artery past the blocked site. The internal mammary ...

  12. 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 ...

  13. 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.

  14. 14 CFR 93.223 - Slot withdrawal.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Allocation of Commuter and Air Carrier IFR... essential air service operations or eliminating slots. Before withdrawing any slots under this section to... service operations shall be exempt from withdrawal for use for other international or essential...

  15. 14 CFR 93.223 - Slot withdrawal.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Allocation of Commuter and Air Carrier IFR... essential air service operations or eliminating slots. Before withdrawing any slots under this section to... service operations shall be exempt from withdrawal for use for other international or essential...

  16. 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.

  17. 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.

  18. 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.

  19. Heart bypass surgery - minimally invasive

    MedlinePlus

    ... in 30-day outcomes in high-risk patients randomized to off-pump versus on-pump coronary bypass ... Thiele H, Neumann-Schniedewind P, Jacobs S, et al. Randomized comparison of minimally invasive direct coronary artery bypass ...

  20. Titanium dioxide slot waveguides for visible wavelengths.

    PubMed

    Häyrinen, Markus; Roussey, Matthieu; Säynätjoki, Antti; Kuittinen, Markku; Honkanen, Seppo

    2015-04-01

    We present the first, to our knowledge, experimental demonstration of a titanium dioxide slot waveguide operating in the visible range of light. Ring resonators based on slot waveguides were designed, fabricated, and characterized for λ≃650  nm. The fabrication method includes atomic layer deposition, electron beam lithography, and reactive ion etching. The required narrow slot widths of a few tens of nanometers were achieved by using a conformal atomic layer re-coating technique. This unique feature-size-reduction technique was applied after the final etching step. PMID:25967172

  1. Sidewall slotted waveguide array antenna with low crosspolar radiation

    NASA Astrophysics Data System (ADS)

    Sangster, A. J.

    1986-05-01

    A new sidewall waveguide slot radiator is described which produces negligible crosspolar radiation fields. This is achieved by employing a noninclined slot inserted into the sidewall of a bifurcated waveguide feed system. The edge slot is excited parasitically by an axially directed septum slot.

  2. 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.

  3. Laparoscopic bypass pyeloureterostomy.

    PubMed

    Noh, Paul H; Shah, Anish K

    2013-02-01

    Minimally invasive surgery has been increasingly applied in paediatric urology, including the treatment of ureteropelvic junction obstruction. To the best of our knowledge, we describe the first laparoscopic bypass pyeloureterostomy in a 3-month-old male infant, with giant hydronephrosis and high insertion of the ureter into the renal pelvis. PMID:22889709

  4. Heart bypass surgery - discharge

    MedlinePlus

    ... Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest . 2012;141:e637S-e68S. Read More Angina Coronary heart disease Heart bypass surgery Heart failure - overview High blood cholesterol levels Smoking - ...

  5. Cardiopulmonary bypass in pregnancy.

    PubMed

    Pomini, F; Mercogliano, D; Cavalletti, C; Caruso, A; Pomini, P

    1996-01-01

    The cardiopathic patient can sustain acute heart failure during pregnancy. In such cases, if open heart operation is necessary to save the patient's life, the fetus could be seriously compromised after exposure to cardiopulmonary bypass. From 1958 to 1992, 69 reports of cardiac operations during pregnancy with the aid of cardiopulmonary bypass have been published. Maternal mortality was 2.9%. Embryofetal mortality was 20.2%. Examining only the last 40 patients, maternal and embryofetal mortality were 0.0% and 12.5%, respectively. Embryofetal mortality was 24.0% when hypothermia was used, compared with 0.0% while operating in normothermia. Maternal mortality did not change. The use of hypothermia during cardiopulmonary bypass provoked uterine contractions in several patients. Hypothermia decreases O2 exchange through the placenta. Pump flow and mean arterial pressure during cardiopulmonary bypass seem to be the most important parameters that influence fetal oxygenation. We speculate that cardiac operation is not a contraindication to pregnancy prolongation. PMID:8561577

  6. Results of experiments with slotted wings

    NASA Technical Reports Server (NTRS)

    Lachmann, G

    1924-01-01

    This report recounts some of the successful experiments conducted in England and Germany on slotted wings and ailerons. Wind tunnel test results are given and examples of aircraft constructed with these new wing components are described.

  7. Waveguide-slot antenna with controlled polarization

    NASA Astrophysics Data System (ADS)

    Kamardinova, V. I.; Kapitanov, V. A.; Nikolaev, A. G.

    A theoretical study, based on experimental data obtained for a waveguide-slot antenna with controlled polarization, is conducted, prompted by the necessity of developing airborne side-looking radars whose antenna is extended in one dimension (along the aircraft fuselage) and has controlled polarization. Emission by an inclined slot in a waveguide of circular cross section is examined; computations and experimental verification of results are carried out for two counterinclined slots. Results of testing of a waveguide with slots at 45 deg to the waveguide generatrix at a wavelength of 3 cm yielded a gain factor of 1300 and radiation pattern width of 1 deg 10 arcmin in the horizontal plane and 5 deg in the vertical. The level of the sidelobe was 13 dB, while that of the following lobes did not exceed 20 dB.

  8. Slot design of optimized electromagnetic pump

    SciTech Connect

    Leboucher, L. . Institut de Mecanique); Villani, D. )

    1993-11-01

    Electromagnetic pumps are used for the transportation of liquid metals such as the cooling sodium of fast breeder nuclear reactors. The design of this induction machine is close to that of a tubular linear induction motor. A non uniform slot distribution is used to optimize electromagnetic pumps. This geometry is tested with a finite element code. The performances are compared with the regular slot distribution of Industrial prototypes.

  9. 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.

  10. Radial slot flows in solid rocket motors

    NASA Astrophysics Data System (ADS)

    Hilbing, J. H.; Heister, S. D.

    1993-06-01

    A series of parametric numerical solutions have been generated to characterize the two-dimensional flowfield due to the presence of a radial slot in a solid rocket propellant grain. Results have been parameterized in terms of upstream core Mach number, slot contraction ratio, and slot-to-core mass flow and momentum ratios. Numerical solutions of the axisymmetric Euler equations have been obtained on a 'generic' slot geometry using a cell-centered, finite volume scheme. Results indicate that both the stagnation pressure loss and grain suction force on the propellant segment downstream of the slot correlate well with slot-to-core momentum ratio; a parameter which has not been used in previous studies. Significant differences (in stagnation pressure losses) have been identified between the 2-D numerical results and the 1-D methods applied in current state-of-the-art ballistics codes. We anticipate that the correlations derived through this parametric study can be used in preliminary performance and grain stress analyses performed during the motor development process.

  11. Slot optical waveguide usage in forming passive optical devices.

    PubMed

    Iqbal, M; Zheng, Z; Liu, J S

    2012-01-01

    We have reviewed the work on SOI slot optical waveguides followed by our work. In a slot waveguide structure, light can be confined in a low index slot guarded by high index slabs. Slot structures are being used in forming complex structures; such as ring resonator circuits. The increased round trip in ring resonator circuits signifies the importance of dispersion calculations. We did analytical and numerical investigations of slot structures' dispersion characteristics. Our dispersion tuned slot structures can help in reducing the dispersion effects on optical signal, which will in turn improve the efficiency of light-on-chip circuits. Since the advent of slot optical waveguides, SOI based slot optical waveguides have been under consideration. It has been found that glass based slot optical waveguide structures with relatively low refractive index contrast ratio can also play an important role in forming complex nano-size optical devices. We made use of power confined inside low index slot regions for a double slot structure. Opto-mechanical sensors have been proposed based upon: (a) variation in power confined inside low index slot region due to the movement of central high index slab under the action of external force (temperature, pressure, humidity, etc). vide Chinese Patent No. ZL 200710176770.1, 2007 (b) variation in power confined inside low refractive index slot regions due to movement of both slots under the action of external force (temperature, pressure, humidity, etc). PMID:21875406

  12. Collision Arbitration Based on Different Slot Times for Slotted-Aloha RFID Systems

    NASA Astrophysics Data System (ADS)

    Lee, Young-Jun; Kwon, Dae-Ken; Kim, Hyoung-Nam

    Tag collision is a major problem in the field of multi-tag identification in RFID systems. To solve this problem, many RFID systems adopt their own collision arbitration algorithms based on framed-structure slotted Aloha (FSSA) due to the simplicity of implementation. The frame size, meaning the number of slots in a frame, is a very important factor to inventory tags' responses in the FSSA. How to assign the frame size is therefore crucial to the collision arbitration performance. Since the existing collision arbitration methods do not consider the slot times of each slot when assigning frame size, they may increase overall identification time. By involving the slot times, we improve the collision arbitration performance of the conventional methods. Simulation results show that collision arbitration based on the proposed method is superior to that based on the conventional methods, irrespective of the number of tags.

  13. The improvement of sidelobe performance of slotted waveguide arrays

    NASA Astrophysics Data System (ADS)

    Alexander, M. J.

    1982-09-01

    Consideration is given to the design of nonresonant slotted waveguide arrays in which the conventional limitations of sidelobe performance are overcome. The design is based on measurements of the radiated amplitude and phase characteristics of a single slot. Assuming a given waveguide cross section for a given frequency, the parameters affecting the slot coupling factor include the following: slot pitch, slot width, thickness of the slotted wall, and parallel plate separation. The design requires further refining with regard to reducing the level of the grating lobes.

  14. 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.

  15. Low-Voltage Bypass Device

    NASA Technical Reports Server (NTRS)

    Wilson, J. P.

    1994-01-01

    Improved bypass device provides low-resistance current shunt around low-voltage power cell when cell fails in open-circuit condition during operation. In comparison with older bypass devices for same application, this one weighs less, generates less heat, and has lower voltage drop (less resistance). Bypass device connected in parallel with power cell. Draws very little current during normal operation of cell.

  16. Solvent casting flow from slot die

    NASA Astrophysics Data System (ADS)

    Lee, Semi; Nam, Jaewook

    2015-11-01

    A continuous solvent casting method using a slot die can precisely control the film thickness by adjusting the operating conditions, such as the belt speed and pumping rate, not the liquid property. Therefore, it is a suitable method for high precision continuous film production. In this particular method, the dope, or casting solution, is pumped through the feed slot to form a short curtain between the die and the moving belt. Although this method is widely used in producing films for various applications, it is difficult to find indepth analyses of such flow. In this study, we developed a finite element computational model for the steady-state two-dimensional sovent casting flow from the slot die. The effect of die configurations, rheological properties and operating conditions on the behavior and shape of the gas/liquid interfaces and the location of the dynamic contact line, which is the place where the dope meets the moving belt, were investigated.

  17. 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.

  18. 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. PMID:25604137

  19. High slot utilization systems for electric machines

    SciTech Connect

    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.

  20. 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.

  1. Endfire tapered slot antennas on dielectric substrates

    NASA Astrophysics Data System (ADS)

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

    1985-12-01

    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.

  2. 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.

  3. 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…

  4. 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.

  5. 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.

  6. 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.

  7. 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…

  8. 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

  9. Slot antenna SIS mixers for submillimeter wavelengths

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    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

  10. 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.

  11. Breathless after bypass

    PubMed Central

    Pearse, Simon G; Missouris, Constantinos; Qureshi, Muhammad Ali

    2014-01-01

    A 65-year-old normotensive, non-athletic man presented to the cardiology clinic with exertional dyspnoea and chest discomfort. Echocardiography revealed mild left ventricular hypertrophy with good systolic function but with regional wall motion abnormalities suggesting ischaemia. Coronary angiography showed significant three-vessel disease. He underwent coronary artery bypass surgery, which was complicated by recurrent pericardial and pleural effusions, requiring a pericardial window procedure. Over the following year he became increasingly oedematous and breathless. On ECG the complexes were low voltage with impaired R wave progression and atrial fibrillation. Echocardiography revealed progression of the left ventricular hypertrophy (LVH) with a bright myocardium and restrictive filling pattern. MRI scanning confirmed the diagnosis of cardiac amyloidosis. He was referred for transplant but was considered unsuitable due to extensive mediastinal scarring. This case demonstrates the importance of a high index of suspicion for amyloidosis, especially in patients with unexplained LVH. Cardiac MRI or biopsy may expedite the diagnosis. PMID:24895396

  12. 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. PMID:26872706

  13. 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.

  14. 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.

  15. 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.

  16. Heart bypass surgery - minimally invasive

    MedlinePlus

    ... MIDCAB; Robot assisted coronary artery bypass; RACAB; Keyhole heart surgery ... To perform this surgery: The heart surgeon will make a 3- to 5-inch-long surgical cut in the left part of your chest between your ribs ...

  17. 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.

  18. How to accurately bypass damage

    PubMed Central

    Broyde, Suse; Patel, Dinshaw J.

    2016-01-01

    Ultraviolet radiation can cause cancer through DNA damage — specifically, by linking adjacent thymine bases. Crystal structures show how the enzyme DNA polymerase η accurately bypasses such lesions, offering protection. PMID:20577203

  19. 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.

  20. Hybrid layered polymer slot waveguide Young interferometer.

    PubMed

    Ahmadi, Leila; Hiltunen, Marianne; Stenberg, Petri; Hiltunen, Jussi; Aikio, Sanna; Roussey, Matthieu; Saarinen, Jyrki; Honkanen, Seppo

    2016-05-16

    We demonstrate a polymer slot waveguide Young interferometer coated with a bilayer of Al2O3/TiO2. The approach enables relaxed dimensions of the polymer waveguide which simplifies the fabrication of the structure with a resolution of 50 nm. The layers were coated by an atomic layer deposition technique. The feasibility of the device was investigated by exploiting the interferometric structure as a bulk refractive index sensor operating at 975 nm wavelength for detection of an ethanol-water solution. A refractive index change of 1 × 10-6 RIU with a sensing length of only 800 µm was detected. The approach confirms the possibility of realizing a low cost device with a small footprint and enhanced sensitivity by employing the TiO2 rails in the sides of the slot waveguide. PMID:27409852

  1. 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. PMID:25734874

  2. Magnetic resonance of slotted circular cylinder resonators

    NASA Astrophysics Data System (ADS)

    Du, Junjie; Liu, Shiyang; Lin, Zhifang; Chui, S. T.

    2008-07-01

    By a rigorous full-wave approach, a systemic study is made on the magnetic resonance of slotted circular cylinder resonators (SCCRs) made of a perfect conductor for the lossless case. This is a two-dimensional analog of the split-ring resonator and may serve as an alternative type of essential constituent of electromagnetic metamaterials. It is found that the resonance frequency can be modulated by changing the geometrical parameters and the dielectrics filling in the cavity and the slot. An approximate empirical expression is presented for magnetic resonance frequency of SCCRs from the viewpoint of an L-C circuit system. Finally, it is demonstrated that the SCCR structure can be miniaturized to less than 1/150 resonant wavelength in size with the dielectrics available currently.

  3. 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.

  4. Bandwidth characteristics of monopulse slotted waveguide antennas

    NASA Astrophysics Data System (ADS)

    Derneryd, A.; Peterson, R.

    Slotted waveguide antennas are of resonant and nonresonant type; the former generate a beam normal to the aperture, rendering them suitable for monopulse antenna applications. Attention is presently given to the improvement of resonant antenna impedance matching through a process of waveguide overloading. The combination of an overloaded waveguide and a transformer will generally have a broader impedance match than the antenna matched by itself; this phenomenon is discussed from both impedance-match and sidelobe level viewpoints.

  5. 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 M.

    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

  6. 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.

  7. 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.

  8. Bypass rewiring and robustness of complex networks.

    PubMed

    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. PMID:27627320

  9. Design of waveguide-fed series slot arrays

    NASA Astrophysics Data System (ADS)

    Orefice, M.; Elliott, R. S.

    1982-08-01

    A design procedure is presented whereby the length and tilt of every slot in a series array can be determined, in the presence of external mutual coupling, in order to provide a specified pattern and input impedance. The slots are cut in a broadwall of rectangular waveguides, centred but inclined, and resonantly spaced to form linear or planar arrays. The design procedure parallels earlier treatment of the longitudinal shunt slot case, and combines Stevenson's method with a modified form of Booker's relation to treat nonresonant series slots. Two coupled design equations result, one linking slot voltage and mode current, the other linking active slot impedance to the active impedance in an equivalent dipole array. Simultaneous solution of these design equations is illustrated for the cases of a two by four array, a three by five array, and a five by five array. Experimental results for the two by four array are presented, and validate the theory satisfactorily.

  10. 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.

  11. Design and analysis of slotted waveguide antenna arrays

    NASA Astrophysics Data System (ADS)

    Richardson, Phillip N.; Yee, Hung Yuet

    1988-06-01

    The typical design of a waveguide slot array begins with an examination of the requirements connected with the definition of the size of the array, the types of slots, and feed methods; this is followed by analysis to determine the dimensions and positions of each slot, and a prediction of array performance; the final step is fabrication and test of a breadboard model to validate the analytical design. These design and analysis aspects are considered in connection with the types of waveguide slots, slot-array architecture, equivalent circuit models, pattern calculations, and analysis techniques. Attention is also given to the use of available design data, experimental techniques, tests using subarrays, experimental measurements of radiating slots, and near-field and far-field measurements.

  12. 14 CFR 93.218 - Slots for transborder service to and from Canada.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 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...

  13. 14 CFR 93.218 - Slots for transborder service to and from Canada.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 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...

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

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 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...

  15. Theoretical design/synthesis of slotted waveguide arrays

    NASA Astrophysics Data System (ADS)

    Sangster, A. J.; McCormick, A. H. I.

    1989-02-01

    A computer-aided design/synthesis procedure for array antennas of the slotted-waveguide type is described. It differs from earlier contributions to this topic in that it uses theoretically evaluated self-admittances, rather than measured self-admittances, for the individual broadwall slots in the array. By adopting the moment method to generate the slot self-admittances, it is shown that accuracies which are comparable with those obtained from a measurement-based procedure can be achieved.

  16. Postoperative bypass bleeding: a bypass-associated dilutional (BAD) coagulopathy?

    PubMed

    Bull, Brian S; Hay, Karen L; Herrmann, Paul C

    2009-01-01

    A number of associations with post-bypass bleeding have been described in the accompanying paper. Herein we hypothesize that dilution is an underlying cause through a malign series of bypass-associated events. Heparinized blood behaves anomalously when diluted. Clotting times first shorten somewhat, then--as the dilution of whole blood approaches 50%--rapidly lengthen to unclottability. During cardiopulmonary bypass, low blood volume patients are at a significant risk of clotting factor dilution which will always be more severe than the level of whole blood dilution. If severe enough, this dilution may lower plasma clotting factors to a critical level and may result in excess protamine administration, secondary to overestimation of heparin. The presence of un-neutralized protamine combined with critically lowered clotting factors leads to marked coagulopathy. PMID:19699663

  17. 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.

  18. 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.

  19. Millimetric nonreciprocal coupled-slot finline components

    NASA Astrophysics Data System (ADS)

    Davis, L. E.; Sillars, D. B.

    1986-07-01

    Promising preliminary results are presented for isolators and a four-port circulator in novel finline structures in the frequency range 26.5-40.0 GHz. The basic configuration is a ferrite-loaded coupled-slot finline with the ferrite magnetized parallel with the direction of propagation. The nonreciprocal effects of the odd mode propagating alone and of the odd and even modes propagating are described. All structures exhibit a 20-dB isolation bandwidth greater than 3.6 GHz. It is suggested that such structures would also be suitable for higher frequencies.

  20. Heat exchanger bypass test report

    SciTech Connect

    De Vries, M.L.

    1995-01-26

    This test report documents the results that were obtained while conducting the test procedure which bypassed the heat exchangers in the HC-21C sludge stabilization process. The test was performed on November 15, 1994 using WHC-SD-CP-TC-031, ``Heat Exchanger Bypass Test Procedure.`` The primary objective of the test procedure was to determine if the heat exchangers were contributing to condensation of moisture in the off-gas line. This condensation was observed in the rotameters. Also, a secondary objective was to determine if temperatures at the rotameters would be too high and damage them or make them inaccurate without the heat exchangers in place.

  1. 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.

  2. POST CORONARY ARTERY BYPASS GRAFT STUDY (CABG)

    EPA Science Inventory

    Relative effectiveness of moderate versus more aggressive lipid lowering, and of low dose anticoagulation versus placebo, in delaying saphenous vein coronary bypass graft atherosclerosis and preventing occlusion of saphenous grafts of patients with saphenous vein coronary bypass ...

  3. 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)

  4. MedlinePlus: Coronary Artery Bypass Surgery

    MedlinePlus

    ... and Blood Institute Start Here Coronary Artery Bypass (Texas Heart Institute) Also in Spanish Coronary Artery Bypass ... and Blood Institute) Specifics Limited-Access Heart Surgery (Texas Heart Institute) Also in Spanish Types of Coronary ...

  5. 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.

  6. 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.

  7. Multiwavelength Emission From Pulsar Slot Gaps

    NASA Technical Reports Server (NTRS)

    Harding, Alice K.; Stern, Julie; Dyks, Jarek

    2008-01-01

    We present results of a 3D model of optical to gamma-ray emission from the slot gap accelerator of a rotation-powered pulsar. Primary electrons accelerating to high altitude in the pulsar magnetosphere at the outer edge of the open field volume, as well as electron-positron pairs on field line interior to the slot gap, radiate curvature, inverse Compton and synchrotron radiation. Both primaries and pairs undergo cyclotron resonant absorption of radio photons, allowing them to maintain significant pitch angles and to produce a broad spectrum of emission from infra-red to GeV energies. Synchrotron radiation from pairs with a power-law energy spectrum dominate the spectrum up to 10 MeV. Synchrotron and curvature radiation of primaries dominates from 10 MeV up to a few GeV. The high-energy pulse profiles are dominated by caustics on trailing field lines. In the case of the Crab pulsar, the radio conal emission may also form caustics in phase with the high-energy peaks. If resonant absorption of radio emission produces high-energy synchroti-on radiation, emission below 200 Mev is expected to exhibit correlations in time and phase with the radio emission.

  8. 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.

  9. 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. PMID:24815285

  10. 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.

  11. 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 93.215 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED... operator must notify the office specified in § 93.221(a)(1), in writing, of those slots used for...

  12. 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 236.809 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... § 236.809 Signal, slotted mechanical. A mechanically operated signal with an electromagnetic...

  13. Slotted orifice flowmeter. Final report, July 1993-August 1995

    SciTech Connect

    Morrison, G.L.

    1995-09-01

    The report shows that a slotted orifice has superior performance characteristics compared to a standard orifice by being significantly less dependent upon upstream flow conditioning than a standard orifice plate. The effectiveness of the slotted orifice as a flow condition is shown.

  14. 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…

  15. Slot-Filler Categories as Memory Organizers for Young Children.

    ERIC Educational Resources Information Center

    Lucariello, Joan; Nelson, Katherine

    1985-01-01

    Two experiments tested the hypothesis that scripts (event schemas) provide a basis for categorical structures in semantic memory. Significantly better memory and organization were achieved on slot-filler lists than on either taxonomic or complementary lists, suggesting that slot-filler categories are more available in preschoolers' semantic…

  16. Electrochemical machining development for turbine generator rotor slots. Final report

    SciTech Connect

    Not Available

    1984-03-01

    The Electrochemical Machining Development for Turbine Generator Rotor Slots was initiated to provide a viable alternative to conventional machining of slots in conventional rotor forging materials and in advanced metallurgical alloys. ECM was selected because it is a stress-free machining process and is insensitive to material hardness. ECM concepts were developed and reviewed with ECM consultants prior to development work.

  17. 14 CFR 93.227 - Slot use and loss.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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.

  3. Compact bypass-flow filter

    NASA Technical Reports Server (NTRS)

    Swift, W. G.; Ulanovsky, J. M.

    1979-01-01

    Annular filter consisting of stacked rings separates particulates from bypass fluid passing through it in radial direction without slowing down main flow across unimpeded flow of fluid through its center. Applications include fluidized bed reactors, equipment for catalyst operations, and water purification.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Slab waveguide theory for general multi-slot waveguide

    NASA Astrophysics Data System (ADS)

    Le, ZiChun; Yin, LiXiang; Zou, Yu; Wu, Xiang

    2016-07-01

    Optical devices based on slot waveguide are of considerable interest in numerous applications due to the distinct feature of strong electric field confinement in a low-refractive index region. A theoretical model based on multi-slab waveguide theory is used to reveal the physical mechanism of the slot waveguide. The calculation results derived from the basic Helmholtz equation for the conventional single-slot waveguide with a ~2% validation of the effective refractive index are compared to the former experiment results by the Cornell University group. Moreover, we extend the theoretical model to a general multi-slot waveguide. Its electric field distribution and key properties such as optical power confinement factor and enhancement factor in slot are deduced theoretically and fully discussed.

  9. Novel Dynamic Framed-Slotted ALOHA Using Litmus Slots in RFID Systems

    NASA Astrophysics Data System (ADS)

    Yim, Soon-Bin; Park, Jongho; Lee, Tae-Jin

    Dynamic Framed Slotted ALOHA (DFSA) is one of the most popular protocols to resolve tag collisions in RFID systems. In DFSA, it is widely known that the optimal performance is achieved when the frame size is equal to the number of tags. So, a reader dynamically adjusts the next frame size according to the current number of tags. Thus it is important to estimate the number of tags exactly. In this paper, we propose a novel tag estimation and identification method using litmus (test) slots for DFSA. We compare the performance of the proposed method with those of existing methods by analysis. We conduct simulations and show that our scheme improves the speed of tag identification.

  10. 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.

  11. 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.

  12. 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…

  13. Moment method analysis of a T-shaped slot radiator in bifurcated waveguide

    NASA Astrophysics Data System (ADS)

    Sangster, A. J.; Lyon, R. W.

    1982-12-01

    A moment analysis technique is employed to study a transverse slot straddling the bifurcation in a slotted waveguide linear antenna array. Sinusoidally-based functions are used to establish the slot coordinate system, with the Green's function serving to determine the scattering parameters of the slot. A transmission-line model of the T-slot is developed, and a transverse resonance method establishes the fields within the slot. Comparisons of the model predictions with results for measured scattering produced by a T-slot in an X band bifurcated rectangular waveguide show satisfactory agreement.

  14. Numerical calculation of boundary-induced interference in slotted or perforated wind tunnels including viscous effects in slots

    NASA Technical Reports Server (NTRS)

    Keller, J. D.

    1972-01-01

    A numerical method is presented for calculating the incompressible boundary-induced interference in wind tunnels of rectangular cross section with slotted or perforated walls. The method includes a wall representation which is capable of satisfying a generalized homogeneous boundary condition including the effects of viscosity within the slots. The effects of viscosity in the slots are found to be very significant. The method allows for a variation in the boundary conditions along the tunnel walls. The model can be any configuration and can be located anywhere in the test section. The interference can be computed at any point in the test section.

  15. The dynamic modelling of a slotted test section

    NASA Technical Reports Server (NTRS)

    Gumas, G.

    1979-01-01

    A mathematical model of the wind tunnel dynamics was developed. The modelling techniques were restricted to the use of one dimensional unsteady flow. The dynamic characteristics of slotted test section incorporated into the model are presented.

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

    PubMed

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

    2016-07-21

    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. PMID:27353219

  17. Aerodynamic sound generated by a slotted trailing edge

    NASA Astrophysics Data System (ADS)

    Howe, M. S.

    1980-11-01

    The theory of the generation of sound by turbulent flow over a trailing edge flap of an airfoil or guidevane is analyzed by using a narrow slot which separates the flap from the airfoil. The configuration is modeled by a semiinfinite rigid plate with a slot at an arbitrary, finite distance from the edge; the aerodynamic sound problem is formulated in terms of an integral equation solved in closed form when the width of the slot is small compared with the acoustic wavelength and the chord of the flap. It was found that at low subsonic mean flow Mach numbers, the slot reduces the level of the radiated noise provided the product of the characteristic wave number and the chord of the flap does not exceed 10.

  18. 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...

  19. 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...

  20. 14 CFR 93.221 - Transfer of slots.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 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...

  1. 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...

  2. 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...

  3. Sensitive detection of yeast using terahertz slot antennas.

    PubMed

    Park, S J; Son, B H; Choi, S J; Kim, H S; Ahn, Y H

    2014-12-15

    We demonstrated sensitive detection of individual yeast cells and yeast films by using slot antenna arrays operating in the terahertz frequency range. Microorganisms located at the slot area cause a shift in the resonant frequency of the THz transmission. The shift was investigated as a function of the surface number density for a set of devices fabricated on different substrates. In particular, sensors fabricated on a substrate with relatively low permittivity demonstrate higher sensitivity. The frequency shift decreases with increasing slot antenna width for a fixed coverage of yeast film, indicating a field enhancement effect. Furthermore, the vertical range of the effective sensing volume has been studied by varying the thickness of the yeast film. The resonant frequency shift saturates at 3.5 μm for a slot width of 2 μm. In addition, the results of finite-difference time-domain simulations are in good agreement with our experimental data. PMID:25606992

  4. Efficient second harmonic generation in internal asymmetric plasmonic slot waveguide.

    PubMed

    Huang, Tianye; Tagne, Patrick Moteng; Fu, Songnian

    2016-05-01

    We theoretically propose an internal asymmetric plasmonic slot waveguide (IAPSW), containing two different materials in the slot region. The IAPSW is used for second harmonic generation (SHG) at a wavelength of 1.55 μm. The required phase matching condition is satisfied between the 0th-order mode at the fundamental frequency and the 1st-order mode at the second harmonic frequency. By choosing appropriate slot geometry and materials, the mode field distribution is engineered to enhance the nonlinear coupling coefficient for SHG. With an 11 μm long IAPSW, a conversion efficiency of 24% (1.8 × 105 W-1cm-2 normalized conversion efficiency) is predicted. Furthermore, the SHG efficiency is more pronounced in IAPSW with thinner slot. PMID:27137584

  5. 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.

  6. Analysis of finite multifrequency slotted waveguide antenna arrays

    NASA Astrophysics Data System (ADS)

    Ponomarev, L. I.; Rud', S. V.; Ryzhikov, A. V.

    1988-02-01

    A model of a finite multifrequency slotted waveguide antenna array based on multimode waveguides is developed on the basis of an integral-equation method. Numerical-analysis results are presented which make it possible to assess the mutual distortions introduced in the radiation characteristics in each of the operating subbands. It is noted that these distortions can be minimized by a proper mutual arrangement of the slots as well as by an appropriate type of waveguide excitation.

  7. 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.

  8. Bypass transition to turbulence and research Desiderata

    NASA Technical Reports Server (NTRS)

    Morkovin, M. V.

    1985-01-01

    Bypass transitions are seldom mentioned in texts or meetings on instability and transition to wall turbulence. The nature of a number of bypass transitions is illustrated by example. Until this characteristics is truly understood predicting transition on the basis of theory or statistically inadequate correlations (as they all are) entails risks that should be considered in justifying any design involving transition. A historical overview of bypass transition identified on blunt bodies is given.

  9. 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.

  10. 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.

  11. 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.

  12. Heart bypass surgery - minimally invasive - discharge

    MedlinePlus

    ... Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest . ... bypass surgery - minimally invasive Heart failure - overview High blood cholesterol ...

  13. Compact slot-in-type optical correlator

    NASA Astrophysics Data System (ADS)

    Yamamoto, Shota; Kuboyama, Hirotoshi; Arai, Shinichi; Yamaguchi, Kenzo; Fukuda, Mitsuo; Kato, Makoto; Kawaguchi, Tadahiko; Inoue, Mitsuteru

    2010-05-01

    We present a new slot-in type of optical correlator that is more compact than the previous types. The correlator can fit inside the cabinet of commercial personal computers and is fully controllable with windows-based software. The correlator is a Joint Transform type (JTC) and its optical system fits inside a metal box measuring 140 mm (W) x 220 mm (L) x 40 mm (H). The optical source is a 650-nm-band laser diode of the kind used in DVD systems. A spatial light modulator and a CMOS camera are installed in the metal box with the passive optical components required for the JTC. The collimated light from the laser diode is illuminated on the spatial light modulator displaying reference and data to be examined. The light reflected from the modulator is Fourier-transformed by a lens on the plane of the CMOS camera. The computer reads the power spectrum recorded by the camera and modulates the spatial light modulator. This process is repeated. We found that these JTC processes could be performed with the prototype developed in this study.

  14. Fish Allergy

    MedlinePlus

    ... Story" 5 Things to Know About Zika & Pregnancy Fish Allergy KidsHealth > For Parents > Fish Allergy Print A ... From Home en español Alergia al pescado About Fish Allergy A fish allergy is not exactly the ...

  15. Electroencephalographic seizures during cardiopulmonary bypass

    PubMed Central

    Stockard, J.; Calanchini, P.; Bickford, R.; Billinger, T.

    1974-01-01

    Eleven cardiac operations are reported in which there was electroencephalographic and/or clinical evidence of seizure activity during cardiopulmonary bypass (CPB). In four patients seizure activity appeared after acute episodes of cerebral ischaemia resulting from either hypotension or pump-generated emboli occurring at the beginning of CPB, or from air embolism occurring at the end of CPB when the myocardium was closed and defibrillated. In the remaining seven patients the seizures appeared to result from the synergistic action of a toxic substance in the perfusate with pre-existing or CPB-induced alterations in cerebral physiology. Images PMID:4819907

  16. 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.

  17. 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)

  18. The effect of slots on the buckling and postbuckling behavior of laminated plates

    NASA Technical Reports Server (NTRS)

    Gurdal, Z.; Haftka, R. T.; Starnes, J. H., Jr.

    1985-01-01

    An experimental study was conducted to evaluate the effect of lateral slots on the buckling response, the postbuckling response, and the failure characteristics of flat rectangular graphite-epoxy plates loaded in compression. The slots did not significantly affect the prebuckling and buckling behavior of the plates. The slots caused local changes in the strain distribution and out-of-plane deformations near the slot. Failure loads and modes were strongly affected by slot location. Centrally located slots did not affect the failure loads or failure modes of the plates. Slots located close to an unloaded edge of a plate reduced the postbuckling strength of the plate and affected the failure mode. For one slightly offset slot location, interaction of out-of-plane deformations with the slot tip was observed to affect the failure mode significantly without affecting the failure load.

  19. 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

  20. 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

  1. 40 CFR 403.17 - Bypass.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 29 2014-07-01 2012-07-01 true Bypass. 403.17 Section 403.17 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS GENERAL PRETREATMENT REGULATIONS FOR EXISTING AND NEW SOURCES OF POLLUTION § 403.17 Bypass....

  2. 40 CFR 403.17 - Bypass.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 30 2013-07-01 2012-07-01 true Bypass. 403.17 Section 403.17 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS GENERAL PRETREATMENT REGULATIONS FOR EXISTING AND NEW SOURCES OF POLLUTION § 403.17 Bypass....

  3. 40 CFR 403.17 - Bypass.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 30 2012-07-01 2012-07-01 false Bypass. 403.17 Section 403.17 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS GENERAL PRETREATMENT REGULATIONS FOR EXISTING AND NEW SOURCES OF POLLUTION § 403.17 Bypass....

  4. 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....

  5. Bypassing An Open-Circuit Power Cell

    NASA Technical Reports Server (NTRS)

    Wannemacher, Harry E.

    1994-01-01

    Collection of bypass circuits enables battery consisting series string of cells to continue to function when one of its cells fails in open-circuit (high-resistance) condition. Basic idea simply to shunt current around defective cell to prevent open circuit from turning off battery altogether. Bypass circuits dissipate little power and are nearly immune to false activation.

  6. 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....

  7. 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

  8. Humanizing machines: Anthropomorphization of slot machines increases gambling.

    PubMed

    Riva, Paolo; Sacchi, Simona; Brambilla, Marco

    2015-12-01

    Do people gamble more on slot machines if they think that they are playing against humanlike minds rather than mathematical algorithms? Research has shown that people have a strong cognitive tendency to imbue humanlike mental states to nonhuman entities (i.e., anthropomorphism). The present research tested whether anthropomorphizing slot machines would increase gambling. Four studies manipulated slot machine anthropomorphization and found that exposing people to an anthropomorphized description of a slot machine increased gambling behavior and reduced gambling outcomes. Such findings emerged using tasks that focused on gambling behavior (Studies 1 to 3) as well as in experimental paradigms that included gambling outcomes (Studies 2 to 4). We found that gambling outcomes decrease because participants primed with the anthropomorphic slot machine gambled more (Study 4). Furthermore, we found that high-arousal positive emotions (e.g., feeling excited) played a role in the effect of anthropomorphism on gambling behavior (Studies 3 and 4). Our research indicates that the psychological process of gambling-machine anthropomorphism can be advantageous for the gaming industry; however, this may come at great expense for gamblers' (and their families') economic resources and psychological well-being. PMID:26322589

  9. Longitudinally slotted conical horn antenna with small flare angle

    NASA Astrophysics Data System (ADS)

    Scharten, T.; Nellen, J.; van den Bogaart, F.

    1981-06-01

    The radiation and cross polarization characteristics of a longitudinally slotted, conical horn antenna with small flare angle, excited in the modified TE(11) mode, are investigated. To this end the electromagnetic wave propagation in a longitudinally slotted circular waveguide is studied first, using a wall reactance model. Because of the need to introduce mode-dependent wall reactances in the present structure, conditions for orthogonality are given. Propagation characteristics and field line patterns are presented. It turns out that the modified TE(11) mode in this guide, used as an aperture antenna, produces a main radiation lobe which can be made nearly symmetrical around the axis over a wide frequency range by a proper choice of the slot depth. As a typical example, the maximum cross polarization level in the main lobe is lower than -30 to -45 dB, dependent on slot depth and frequency range. Experiments carried out with a slotted conical horn antenna with small flare angle confirm the theoretical results.

  10. Post-Gastric Bypass Hypoglycemia.

    PubMed

    Rariy, Chevon M; Rometo, David; Korytkowski, Mary

    2016-02-01

    Obesity is a major public health problem worldwide. Obesity-related illnesses, such as coronary heart disease, type 2 diabetes, hypertension, dyslipidemia, stroke, sleep apnea, and several forms of cancer (endometrial, breast, and colon), contribute to a significant number of deaths in the USA. Bariatric surgery, including the Roux-en-Y gastric bypass (RYGB) procedure, has demonstrated significant improvements in obesity and obesity-related co-morbidities and is becoming more popular as the number of obese individuals rises. Despite the reported benefits of bariatric surgery, there are potential complications that physicians need to be aware of as the number of patients undergoing these procedures continues to increase. One challenging and potentially life-threatening complication that to date is not well understood is post-RYGB surgery hypoglycemia (PGBH). In this review, we will present the definition, historical perspective, diagnostic approach, currently available treatment options, and anecdotal assessment and treatment algorithm for this disorder. PMID:26868861

  11. Analysis of the transverse electromagnetic mode linearly tapered slot antenna

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

    A theoretical analysis of the radiation characteristics of the transverse electromagnetic mode linearly tapered slot antenna 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. 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.

  12. 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.

  13. Slotted third-harmonic gyro-TWT amplifier experiment

    SciTech Connect

    Chong, C.K.; McDermott, D.B.; Luhmann, N.C. Jr.

    1996-06-01

    The first operation of a slotted third-harmonic gyrotron traveling-wave amplifier is reported. The low-magnetic-field moderate-voltage gyrotron amplifier`s 62-keV 2.5-A {upsilon}{sub {perpendicular}}/{upsilon}{sub {parallel}} = 1.2 axis-encircling electron beam was supplied by a gyroresonant RF accelerator. The 10-GHz 1.3-kG single-section slotted third-harmonic amplifier is stable and yielded 12.5 dB of small-signal gain with a bandwidth of 2.5%. The experiment was performed as a scaled proof-of-principle test of the 95-GHz multisection slotted amplifier under development at CPI (formerly Varian).

  14. 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.

  15. 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.

  16. A 94 GHz imaging array using slot line radiators

    NASA Astrophysics Data System (ADS)

    Korzeniowski, T. L.

    1985-09-01

    A planar endfire slotted-line antenna structure was investigated. It was found that the H-plane beamwidths are basically dependent upon the substrate properties, whereas the E-plane beamwidths are more strongly a function of the slot's shape and size. It is shown that these antennas produce symmetrical E and H-plane beamwidths while following Zucker's standard traveling-wave antenna beamwidth curves over some range of antenna normalized length. An empircally derived design formula for effective substrate thickness is shown to predict this range for linearly tapered slotted-line antennas. The experimental imaging properties of these arrays are presented and imaging theory is discussed. It is shown that a minimum spacing of elements is necessary for exact reconstruction for a sampled image in a diffraction limited system. Because these LTSA elements employ the traveling-wave mechanism of radiation, they can be spaced two times closer than a conical feed horn of comparable beamwidth.

  17. Comparison of heat transfer characteristics of a slot jet reattachment nozzle and a conventional slot jet nozzle

    SciTech Connect

    Narayanan, V.; Seyed-Yagoobi, J.; Page, R.H.

    1996-12-31

    A new type of nozzle, the Slot Jet Reattachment Nozzle (SJR), was designed and built with a zero degree exit angle. The heat transfer characteristics of the submerged SJR nozzle were compared to a conventional submerged slot jet nozzle. The comparisons were made under identical air flow power at each nozzle`s favorable height from the impinging surface. Infrared imaging techniques were used to obtain the temperature distributions on the impinging surface. The results indicate that comparable local heat transfer coefficients are obtained by the SJR nozzle while the exerted force on the impinging surface is significantly reduced. The peak local heat transfer coefficient for the SJR nozzle is approximately 8.4% higher than the peak local heat transfer coefficient for the slot jet nozzle under the same flow power. Additional experiments were conducted under matching local peak pressure for the SJR and slot jet nozzles. The results showed significant enhancements, of the order of 1.5 times, in the peak local heat transfer coefficient for the SJR nozzle over the slot jet nozzle.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Finite element calculations for eddy current interactions with collinear slots

    SciTech Connect

    Atherton, D.L.; Czura, W. . Dept. of Physics)

    1994-01-01

    The results of finite element calculations detailing the interactions of eddy currents with fine collinear slots in nonferromagnetic and ferromagnetic conductors are presented. These are applicable to both remote field eddy current inspection tools and conventional reflected impedance eddy current probes. The calculations show that, while fine slots have little interaction with collinear induced currents in nonferromagnetic conductors, there are much larger effects in ferromagnetic conductors. This is due to magnetic field interactions. The term eddy current inspection' is therefore somewhat restrictive and the much broader term electromagnetic inspection' is proposed.

  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. 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

  5. Swept-slot film-cooling effectiveness in hypersonic turbulent flow

    NASA Technical Reports Server (NTRS)

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

    1974-01-01

    Measurement results are presented for the surface equilibrium temperature downstream of swept slots, with sonic tangential air injection into a thick hypersonic turbulent boundary layer. These results are compared with unswept slot results for cooling effectiveness.

  6. 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)

  7. 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)

  8. 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.

  9. 21 CFR 870.4310 - Cardiopulmonary bypass coronary pressure gauge.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 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 2010-04-01 2010-04-01 false Cardiopulmonary bypass coronary pressure...

  10. 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...

  11. 21 CFR 870.4205 - Cardiopulmonary bypass bubble detector.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Cardiopulmonary bypass bubble detector. 870.4205... bypass bubble detector. (a) Identification. A cardiopulmonary bypass bubble detector is a device used to detect bubbles in the arterial return line of the cardiopulmonary bypass circuit. (b)...

  12. 21 CFR 870.4205 - Cardiopulmonary bypass bubble detector.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Cardiopulmonary bypass bubble detector. 870.4205... bypass bubble detector. (a) Identification. A cardiopulmonary bypass bubble detector is a device used to detect bubbles in the arterial return line of the cardiopulmonary bypass circuit. (b)...

  13. 21 CFR 870.4205 - Cardiopulmonary bypass bubble detector.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass bubble detector. 870.4205... bypass bubble detector. (a) Identification. A cardiopulmonary bypass bubble detector is a device used to detect bubbles in the arterial return line of the cardiopulmonary bypass circuit. (b)...

  14. 21 CFR 870.4205 - Cardiopulmonary bypass bubble detector.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Cardiopulmonary bypass bubble detector. 870.4205... bypass bubble detector. (a) Identification. A cardiopulmonary bypass bubble detector is a device used to detect bubbles in the arterial return line of the cardiopulmonary bypass circuit. (b)...

  15. 21 CFR 870.4205 - Cardiopulmonary bypass bubble detector.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cardiopulmonary bypass bubble detector. 870.4205... bypass bubble detector. (a) Identification. A cardiopulmonary bypass bubble detector is a device used to detect bubbles in the arterial return line of the cardiopulmonary bypass circuit. (b)...

  16. 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...

  17. 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...

  18. 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.

  19. 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.

  20. Slot film cooling: A comprehensive experimental characterization

    NASA Astrophysics Data System (ADS)

    Raffan, Fernando

    When components of a propulsion system are exposed to elevated flow temperatures there is a risk for catastrophic failure if the components are not properly protected from the thermal loads. Among several strategies, slot film cooling is one of the most commonly used, yet poorly understood active cooling techniques. Tangential injection of a relatively cool fluid layer protects the surface(s) in question, but the turbulent mixing between the hot mainstream and cooler film along with the presence of the wall presents an inherently complex problem where kinematics, thermal transport and multimodal heat transfer are coupled. Furthermore, new propulsion designs rely heavily on CFD analysis to verify their viability. These CFD models require validation of their results, and the current literature does not provide a comprehensive data set for film cooling that meets all the demands for proper validation, namely a comprehensive (kinematic, thermal and boundary condition data) data set obtained over a wide range of conditions. This body of work aims at solving the fundamental issue of validation by providing high quality comprehensive film cooling data (kinematics, thermal mixing, heat transfer). 3 distinct velocity ratios (VR=u c/uinfinity) are examined corresponding to wall-wake (VR˜0.5), min-shear (VR ˜ 1.0), and wall-jet (VR˜2.0) type flows at injection, while the temperature ratio TR= Tinfinity/Tc is approximately 1.5 for all cases. Turbulence intensities at injection are 2-4% for the mainstream (urms/uinfinity, vrms/uinfinity,), and on the order of 8-10% for the coolant (urms/uc, vrms/uc,). A special emphasis is placed on inlet characterization, since inlet data in the literature is often incomplete or is of relatively low quality for CFD development. The data reveals that min-shear injection provides the best performance, followed by the wall-jet. The wall-wake case is comparably poor in performance. The comprehensive data suggests that this relative performance

  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. Slot-Filler and Conventional Category Organisation in Young Korean Children.

    ERIC Educational Resources Information Center

    Yu, Younoak; Nelson, Katherine

    1993-01-01

    In two experiments, five year olds produced more instances in slot-filler categories than taxonomic categories, and eight year olds produced more instances in taxonomic categories than slot-filler categories; for five year olds, slot-filler categories led to superior recall and shorter response latencies than did taxonomic categories. (BB)

  3. Optimizing the power confinement in silicon slot waveguides by use of finite element method

    NASA Astrophysics Data System (ADS)

    Leung, D. M. H.; Kan, X. B.; Rahman, B. M. A.; Kejalakshmy, N.; Grattan, K. T. V.

    2011-12-01

    In this paper, the power confinement and the power density in the slot region of a vertical and horizontal slot waveguide are optimized; full-vectorial H and E-field profiles along with Poynting vector are also shown for both of these silicon waveguides. Bending loss of such slot waveguides is also presented.

  4. 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

  5. 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.

  6. Bypass diode for a solar cell

    SciTech Connect

    Rim, Seung Bum; Kim, Taeseok; Smith, David D.; Cousins, Peter J.

    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.

  7. 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.

  8. Nonplanar linearly tapered slot antenna with balanced microstrip feed

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.; Lee, Richard Q.; Perl, Thomas D.

    1992-01-01

    A nonplanar linearly tapered slot antenna (LTSA) has been fabricated and tested at frequencies from 8 to 32 giga-Hz. The LTSA is excited by a broadband balanced microstrip transformer. The measured results include the input term return loss as well as the radiation pattern of the antenna.

  9. 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…

  10. RSBP: A Reliable Slotted Broadcast Protocol in Wireless Sensor Networks

    PubMed Central

    Van Vinh, Phan; Oh, Hoon

    2012-01-01

    In wireless sensor networks for monitoring and control applications, a sink node needs to disseminate messages to all nodes to acquire monitoring data or to control the operation of sensor nodes. The basic flooding protocol suffers from low transmission reliability in broadcasting messages due to the hidden terminal problem. Besides, it can cause the broadcast storm problem by having many nodes rebroadcast the received message simultaneously. In order to resolve these problems while minimizing energy consumption in delivery of broadcast messages, we propose a reliable slotted broadcast protocol (RSBP) that allocates broadcast time slots to nodes based on their slot demands and then allows every node to transmit its broadcast message within the allocated slots. Then, every node can broadcast messages safely in a contention-free manner. Moreover, RSBP can be deployed easily since it does not have any specific requirements such as GPS, multi-channels and directional antennas that may not be always available in real scenarios. We show by experimental study that RSBP significantly outperforms other broadcast protocols in terms of safety-critical packet delivery and energy consumption. PMID:23202180

  11. 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....

  12. 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

  13. Circularly polarized printed arrays composed of strip dipoles and slots

    NASA Astrophysics Data System (ADS)

    Ito, Koichi

    1987-04-01

    This paper presents circularly polarized printed arrays composed of strip dipoles and slots (CP-PASS). A design method for CP-PASS is described on the basis of its equivalent circuit model. A linear array with a Chebyshev pattern and a middle-gain planar array are designed and measured at S band.

  14. Slot-coupled excitation of microstrip dipole antennas

    NASA Astrophysics Data System (ADS)

    Ittipiboon, A.; Roscoe, D.; Cuhaci, M.; Antar, Y. M. M.

    1992-01-01

    The slot-coupled method is proposed as an alternative to the popular electromagnetically coupled technique (EMC) for feeding microstrip dipole antennas. This letter describes the basic design procedure and some key advantages of this method over EMC. Experimental results confirm the effective and practical performance of the proposed structure.

  15. Slot-electrode optical modulator using KTiOPO(4).

    PubMed

    Godil, A A; Kikuchi, H; Fukui, T; Kubota, S

    1995-07-20

    A slot-electrode optical modulator is introduced and demonstrated with KTP at 532 nm. A switching voltage of 45 V, risetime of 3.5 ns, and power capability of more than 7 Ware measured. DC modulation without application of DC voltage is discussed. Further optimization can reduce the switching voltage to 18 V. PMID:21052271

  16. 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.

  17. 94 GHz slotted waveguide array fabricated by photolithographic techniques

    NASA Astrophysics Data System (ADS)

    Rao, B. R.

    1984-02-01

    94 GHz nonresonant shunt and series slot waveguide arrays have been fabricated by using high-resolution photolithographic and chemical etching techniques. The antenna pattern, efficiency and input reflection coefficient for the two types of arrays have been measured and are in good agreement with design predictions.

  18. 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.

  19. Contextual Control of Slot-Machine Gambling: Replication and Extension

    ERIC Educational Resources Information Center

    Hoon, Alice; Dymond, Simon; Jackson, James W.; Dixon, Mark R.

    2008-01-01

    Participants were trained and tested to select stimuli of differing physical quantities in the presence of 2 color contextual cues for more than and less than. Following more than and less than relational training, participants allocated the majority of their responses to the slot machine that shared formal properties of color with the contextual…

  20. A planar broad-band flared microstrip slot antenna

    NASA Astrophysics Data System (ADS)

    Povinelli, Mark J.

    1987-08-01

    Experimental results have been obtained on a planar multioctave bandwidth flared microstrip slot. When crossed, the element is capable of horizontal, vertical, or circular polarization. A design was fabricated and measurements were taken to define the performance. The input impedance and radiation characteristics are shown to have a broad-band response when configured as a cavity-backed element.

  1. MAFIA analysis of the effects of coupling slots in linacs

    NASA Astrophysics Data System (ADS)

    Adams, F. P.; Ungrin, J.; de Jong, M. S.

    1991-05-01

    We have used the MAFIA codes to analyze on-axis slot-coupled {π}/{2}- mode standing-wave linac structures. Quadrupolar fields in the structure are found to produce an elliptical accelerated beam. A modification to the design, yielding reduced beam ellipticity, is proposed.

  2. 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

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Fluvial erosion of physically modeled abrasion-dominated slot canyons

    NASA Astrophysics Data System (ADS)

    Carter, Carissa L.; Anderson, Robert S.

    2006-11-01

    Abrasion-dominated fluvial erosion generates slot canyons in massive bedrock with intricately undulating walls. Flows in slot canyons are unusual in that the walls comprise a significant portion of the wetted perimeter of the flow during geomorphically effective floods. In Wire Pass, Utah, the upper Paria River incises through massive, crossbedded Navajo Sandstone. Incision in Wire Pass and related slots occurs only during flash floods; paleoflood debris indicates that the width/depth ratios of these flows are at times as low as 1:1. Submeter resolution field mapping of a 20-m length of Wire Pass shows that the wall morphology is a complicated combination of in-phase (meander-like) and out-of-phase (pinch and swell) undulations. In order to investigate evolution of slot canyons and the influence of their wall shapes on flow dynamics, we recorded the evolution of four distinct canyon wall morphologies in a 2.4 m flume box at the St. Anthony Falls Laboratory. In a substrate consisting of ˜ 3:2 mixtures of F110 sand and Plaster of Paris, we molded canyons with in-phase and out-of-phase undulations, and wide (6.5 cm) and narrow (4 cm) straight initial wall profiles. Discharges ranged from 1.4 L/s to 2.9 L/s, and wall and bed morphology were measured at 5 h intervals at 0.5 cm resolution. Results show efficient back-eddy erosion in the undulating canyon walls and related erosional bedforms in all channels created by vortices in the flow. Maximum filaments of velocity are depressed and asymmetric, and the implied shear stress distribution varied in space and time on the channel beds. Flow width/depth ratios strongly influence the flow structure and distribution of shear stress in a slot and appear to be a factor in dictating whether a bedrock channel widens its walls or incises its bed.

  9. Transgenic Fish

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fish into which foreign DNA is artificially introduced and integrated into their genome are called transgenic fish. Since the development of the first transgenic fish in 1985, techniques to produce transgenic fish have improved tremendously, resulting in the production of genetically modified (GM) ...

  10. A detailed experimental study of the flow in the vicinity of the slotted wall of a wind tunnel with applications to the homogeneous slotted-wall boundary condition

    NASA Technical Reports Server (NTRS)

    Everhart, J. L.

    1986-01-01

    The results of an experimental study of the flow in the vicinity of the slotted wall of a transonic wind tunnel are presented. A general description of the test setup and the wall configurations studied are given as are examples of the pressure data measured on the airfoil and the walls of the tunnel. The flow angles measured in the vicinity of the slot are examined with implications as to their use in the theory of homogeneous slotted walls. Preliminary values of the classical, homogeneous, slotted-wall boundary-condition coefficient are given and compared with theory.