Science.gov

Sample records for corrugated pipe culverts

  1. 15. Culvert and corrugated pipe with place of a thousand ...

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

    15. Culvert and corrugated pipe with place of a thousand drips in background looking S. - Great Smoky Mountains National Park Roads & Bridges, Roaring Fork Motor Nature Trail, Between Cherokee Orchard Road & U.S. Route 321, Gatlinburg, Sevier County, TN

  2. Corrugated pipe adhesive applicator apparatus

    DOEpatents

    Shirey, R.A.

    1983-06-14

    Apparatus for coating selected portions of the troughs of a corrugated pipe with an adhesive includes a support disposed within the pipe with a reservoir containing the adhesive disposed on the support. A pump, including a spout, is utilized for supplying the adhesive from the reservoir to a trough of the pipe. A rotatable applicator is supported on the support and contacts the trough of the pipe. The applicator itself is sized so as to fit within the trough, and contacts the adhesive in the trough and spreads the adhesive in the trough upon rotation. A trough shield, supported by the support and disposed in the path of rotation of the applicator, is utilized to prevent the applicator from contacting selected portions of the trough. A locator head is also disposed on the support and provides a way for aligning the spout, the applicator, and the trough shield with the trough. 4 figs.

  3. Corrugated pipe adhesive applicator apparatus

    DOEpatents

    Shirey, Ray A.

    1983-06-14

    Apparatus for coating selected portions of the troughs of a corrugated pipe within an adhesive includes a support disposed within the pipe with a reservoir containing the adhesive disposed on the support. A pump, including a spout, is utilized for supplying the adhesive from the reservoir to a trough of the pipe. A rotatable applicator is supported on the support and contacts the trough of the pipe. The applicator itself is sized so as to fit within the trough, and contacts the adhesive in the trough and spreads the adhesive in the trough upon rotation. A trough shield, supported by the support and disposed in the path of rotation of the applicator, is utilized to prevent the applicator from contacting selected portions of the trough. A locator head is also disposed on the support and provides a way for aligning the spout, the applicator, and the trough shield with the trough.

  4. Corrugated Pipe as a Beam Dechirper

    SciTech Connect

    Bane, K.L.F.; Stupakov, G.; /SLAC

    2012-04-20

    We have studied the use of a metallic pipe with small corrugations for the purpose of passively dechirping, through its wakefield, a short, intense electron bunch. The corrugated pipe is attractive for this purpose because its wake: (i) has near maximal possible amplitude for a given aperture and (ii) has a relatively large oscillation wave length, even when the aperture is small. We showed how the corrugated structure can satisfy dechirping requirements encountered in the NGLS project at LBNL. We found that a linear chirp of -40 MeV/mm can be induced by an NGLS-like beam, by having it pass through a corrugated, metallic pipe of radius 3 mm, length 8.2 m, and corrugation parameters full depth 450 {mu}m and period 1000 {mu}m. This structure is about 15 times as effective in the role of dechirper as an S-band accelerator structure used passively.

  5. Analysis of brook trout spatial behavior during passage attempts in corrugated culverts using near-infrared illumination video imagery

    USGS Publications Warehouse

    Bergeron, Normand E.; Constantin, Pierre-Marc; Goerig, Elsa; Castro-Santos, Theodore R.

    2016-01-01

    We used video recording and near-infrared illumination to document the spatial behavior of brook trout of various sizes attempting to pass corrugated culverts under different hydraulic conditions. Semi-automated image analysis was used to digitize fish position at high temporal resolution inside the culvert, which allowed calculation of various spatial behavior metrics, including instantaneous ground and swimming speed, path complexity, distance from side walls, velocity preference ratio (mean velocity at fish lateral position/mean crosssectional velocity) as well as number and duration of stops in forward progression. The presentation summarizes the main results and discusses how they could be used to improve fish passage performance in culverts.

  6. Velocity Field Characteristics at the Inlet to a Pipe Culvert

    NASA Astrophysics Data System (ADS)

    Kolerski, Tomasz; Wielgat, Paweł

    2014-12-01

    A poorly designed culvert inlet structure causes scouring, which can lead to the collapse of the culvert and significant damage to the neighboring land. A set of laboratory tests was evaluated to examine velocity distribution at the culvert inlet. A three-dimensional acoustic Doppler velocimeter was used to measure instantaneous flow velocity upstream of the culvert. The analysis of mean velocities, turbulence strength, and Reynolds stresses was performed to understand the flow structure near the culvert entrance.

  7. 78 FR 5715 - Construction and Maintenance-Culvert Pipe Selection

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-28

    ... autonomy to determine culvert and storm sewer material types to be included in the construction of a... congressional mandate to amend 23 CFR 635.411 to allow States to choose culvert and storm sewer material type.... Regulatory History The ``General Material Requirements,'' found in 23 CFR part 635 subpart D,...

  8. Flow Pressure Loss through Straight Annular Corrugated Pipes

    NASA Technical Reports Server (NTRS)

    Sargent, Joseph R.; Kirk, Daniel R.; Marsell, Brandon; Roth, Jacob; Schallhorn, Paul A.; Pitchford, Brian; Weber, Chris; Bulk, Timothy

    2016-01-01

    Pressure loss through annular corrugated pipes, using fully developed gaseous nitrogen representing purge pipes in spacecraft fairings, was studied to gain insight into a friction factor coefficient for these pipes. Twelve pipes were tested: four Annuflex, four Masterflex and two Titeflex with ¼”, 3/8”, ½” and ¾” inner diameters. Experimental set-up was validated using smooth-pipe and showed good agreement to the Moody diagram. Nitrogen flow rates between 0-200 standard cubic feet per hour were used, producing approximate Reynolds numbers from 300-23,000. Corrugation depth varied from 0.248 = E/D = 0.349 and relative corrugation pitch of 0.192 = P/D = 0.483. Differential pressure per unit length was measured and calculated using 8-9 equidistant pressure taps. A detailed experimental uncertainty analysis, including correlated bias error terms, is presented. Results show larger differential pressure losses than smooth-pipes with similar inner diameters resulting in larger friction factor coefficients.

  9. Wall shape optimization for a thermosyphon loop featuring corrugated pipes

    NASA Astrophysics Data System (ADS)

    Rosen Esquivel, Patricio I.; ten Thije Boonkkamp, Jan H. M.; Dam, Jacques A. M.; Mattheij, Robert M. M.

    2012-06-01

    In the present paper we address the problem of optimal wall-shape design of a single phase laminar thermosyphon loop. The model takes the buoyancy forces into account via the Boussinesq approximation. We focus our study on showing the effects of wall shape on the flow and on the temperature inside the thermosyphon. To this extend we determine the dependency of the flow rate and the increase in temperature, on the geometrical characteristics of the loop. The geometry considered is a set of axially symmetric corrugated pipes described by a set of parameters; namely the pipe inner radius, the period of the corrugation, the amplitude of the corrugation, and the ratio of expansion and contraction regions of a period of the pipe. The governing equations are solved using the Finite Element Method, in combination with an adaptive mesh refinement technique in order to capture the effects of wall shape. We characterize the effects of the amplitude and of the ratio of expansion and contraction. In particular we show that for a given fixed amplitude it is possible to find an optimal ratio of expansion and contraction that minimizes the temperature inside the thermosyphon. The results show that by adequately choosing the design parameters, the performance of the thermosyphon loop can be improved.

  10. Terahertz Radiation from a Pipe with Small Corrugations

    SciTech Connect

    Bane, K.L.F.; Stupakov, G.; /SLAC

    2012-01-26

    We have studied through analytical and numerical methods the use of a relativistic electron bunch to drive a metallic beam pipe with small corrugations for the purpose of generating terahertz radiation. For the case of a pipe with dimensions that do not change along its length, we have shown that - with reasonable parameters - one can generate a narrow-band radiation pulse with frequency {approx}1 THz, and total energy of a few milli-Joules. The pulse length tends to be on the order of tens of picoseconds. We have also shown that, if the pipe radius is tapered along its length, the generated pulse will end up with a frequency chirp; if the pulse is then made to pass through a compressor, its final length can be reduced to a few picoseconds and its peak power increased to 1 GW. We have also shown that wall losses tend to be significant and need to be included in the structure design.

  11. Pressure drop of slush nitrogen flow in converging-diverging pipes and corrugated pipes

    NASA Astrophysics Data System (ADS)

    Ohira, Katsuhide; Okuyama, Jun; Nakagomi, Kei; Takahashi, Koichi

    2012-12-01

    Cryogenic slush fluids such as slush hydrogen and slush nitrogen are solid-liquid, two-phase fluids. As a functional thermal fluid, there are high expectations for use of slush fluids in various applications such as fuels for spacecraft engines, clean-energy fuels to improve the efficiency of transportation and storage, and as refrigerants for high-temperature superconducting equipment. Experimental flow tests were performed using slush nitrogen to elucidate pressure-drop characteristics of converging-diverging (C-D) pipes and corrugated pipes. In experimental results regarding pressure drop in two different types of C-D Pipes, i.e., a long-throated pipe and a short-throated pipe, each having an inner diameter of 15 mm, pressure drop for slush nitrogen in the long-throated pipe at a flow velocity of over 1.3 m/s increased by a maximum of 50-60% as compared to that for liquid nitrogen, while the increase was about 4 times as compared to slush nitrogen in the short-throated pipe. At a flow velocity of over 1.5 m/s in the short-throated pipe, pressure drop reduction became apparent, and it was confirmed that the decrease in pressure drop compared to liquid nitrogen was a maximum of 40-50%. In the case of two different types of corrugated pipes with an inner diameter of either 12 mm or 15 mm, a pressure-drop reduction was confirmed at a flow velocity of over 2 m/s, and reached a maximum value of 37% at 30 wt.% compared to liquid nitrogen. The greater the solid fractions, the smaller the pipe friction factor became, and the pipe friction factor at the same solid fraction showed a constant value regardless of the Reynolds number. From the observation of the solid particles' behavior using a high-speed video camera and the PIV method, the pressure-drop reduction mechanisms for both C-D and corrugated pipes were demonstrated.

  12. Surface Impedance Formalism for a Metallic Beam Pipe with Small Corrugations

    SciTech Connect

    Stupakov, G.; Bane, K.L.F.; /SLAC

    2012-08-30

    A metallic pipe with wall corrugations is of special interest in light of recent proposals to use such a pipe for the generation of terahertz radiation and for energy dechirping of electron bunches in free electron lasers. In this paper we calculate the surface impedance of a corrugated metal wall and show that it can be reduced to that of a thin layer with dielectric constant {epsilon} and magnetic permeability {mu}. We develop a technique for the calculation of these constants, given the geometrical parameters of the corrugations. We then calculate, for the specific case of a round metallic pipe with small corrugations, the frequency and strength of the resonant mode excited by a relativistic beam. Our analytical results are compared with numerical simulations, and are shown to agree well.

  13. Simulation and analysis on ultrasonic testing for the cement grouting defects of the corrugated pipe

    SciTech Connect

    Qingbang, Han; Ling, Chen; Changping, Zhu

    2014-02-18

    The defects exist in the cement grouting process of prestressed corrugated pipe may directly impair the bridge safety. In this paper, sound fields propagation in concrete structures with corrugated pipes and the influence of various different defects are simulated and analyzed using finite element method. The simulation results demonstrate a much complex propagation characteristic due to multiple reflection, refraction and scattering, where the scattering signals caused by metal are very strong, while the signals scattered by an air bubble are weaker. The influence of defect both in time and frequency domain are found through deconvolution treatment. In the time domain, the deconvolution signals correspond to larger defect display a larger head wave amplitude and shorter arrive time than those of smaller defects; in the frequency domain, larger defect also shows a stronger amplitude, lower center frequency and lower cutoff frequency.

  14. Wakefield computations for a corrugated pipe as a beam dechirper for FEL applications

    SciTech Connect

    Ng, C. K.; Bane, K. L.F.

    2015-06-09

    A beam “dechirper” based on a corrugated, metallic vacuum chamber has been proposed recently to cancel residual energy chirp in a beam before it enters the undulator in a linac-based X-ray FEL. Rather than the round geometry that was originally proposed, we consider a pipe composed of two parallel plates with corrugations. The advantage is that the strength of the wake effect can be tuned by adjusting the separation of the plates. The separation of the plates is on the order of millimeters, and the corrugations are fractions of a millimeter in size. The dechirper needs to be meters long in order to provide sufficient longitudinal wakefield to cancel the beam chirp. Considerable computation resources are required to determine accurately the wakefield for such a long structure with small corrugation gaps. Combining the moving window technique and parallel computing using multiple processors, the time domain module in the parallel finite-element electromagnetic suite ACE3P allows efficient determination of the wakefield through convergence studies. In this paper, we will calculate the longitudinal, dipole and quadrupole wakefields for the dechirper and compare the results with those of analytical and field matching approaches.

  15. Response of reinforced concrete and corrugated steel pipes to surface load

    NASA Astrophysics Data System (ADS)

    Lay, Geoff R.

    Full-scale simulated live load tests were conducted in a controlled laboratory setting using a single-axle frame on 600-mm-inner-diameter reinforced concrete pipe (RCP) and corrugated steel pipe (CSP) when buried in dense, well-graded sand and gravel. Measurements of the RCP at nominal and working forces and beyond are reported for 0.3, 0.6 and 0.9 m of soil cover above the pipe crown. The RCP experienced no cracking when buried at 0.3 m under nominal and working CL-625 and CL-800 single-axle design loads. At these loads, the vertical contraction of the pipe diameter was less than 0.08 and 0.10 mm and the largest tensile strains in the pipe were 75 and 100 muepsilon (50-60% of the cracking strain), respectively. A 0.15 (+/-0.05)-mm-wide axial crack developed at the inner crown in the presence of a 6 kNm/m circumferential bending moment (70% of the theoretical ultimate moment capacity) at the fully factored CL-625 load. This crack did not propagate or widen from 3 series of cyclic load-unload tests. At 1300 kN of applied load the change in pipe diameter was less than 3.5 mm. Increasing soil cover from 0.3 to 0.6 to 0.9 m reduced the circumferential crown bending moment from 6.0 to 3.9 to 2.1 kNm/m, respectively, at 400 kN of axle load. A 1.6- and a 2.8-mm-thick CSP were also subjected to axle loading. No yielding or limit states occurred in the 1.6-mm-thick CSP when buried 0.9-m-deep. However, at 0.6 m of cover a 300 kN axle load caused local yielding at the pipe crown. Increasing soil cover from 0.6 to 0.9 m decreased the vertical diameter change from -3.0 to -1.2 mm and the crown bending moment from 0.7 to 0.2 kNm/m (75% and 20% of the yield moment), respectively, at a 250 kN axle load. Deflections of the thicker CSP were less than the thinner pipe below the CL-625 single-axle load, however further increases in applied load produced a greater response in the thicker pipe, likely due to a haunch support issue. Shallow axle loading produced a greater 3-dimensional

  16. 1. View east at west facade of culvert outlet headwall, ...

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

    1. View east at west facade of culvert outlet headwall, above which part of the canal bank has been removed. Foreground to background: streambed and coffer dam (mound in center) that was used in dewatering the culvert; intake pipes (extreme left and right) for dewatering pumps; deteriorated culvert outlet headwall with upper portion of wall fallen away; horizontal masonry cutoff wall extending above the culvert outlet partially up the canal bank (cutoff wall was exposed by removal of part of canal bank); towpath at top of canal bank. - Delaware & Raritan Canal, Six Mile Run Culvert, .2 mile South of Blackwells Mills Road, East Millstone, Somerset County, NJ

  17. Brook trout passage performance through culverts

    USGS Publications Warehouse

    Goerig, Elsa; Castro-Santos, Theodore R.; Bergeron, Normand

    2016-01-01

    Culverts can restrict access to habitat for stream-dwelling fishes. We used passive integrated transponder telemetry to quantify passage performance of >1000 wild brook trout (Salvelinus fontinalis) attempting to pass 13 culverts in Quebec under a range of hydraulic and environmental conditions. Several variables influenced passage success, including complex interactions between physiology and behavior, hydraulics, and structural characteristics. The probability of successful passage was greater through corrugated metal culverts than through smooth ones, particularly among smaller fish. Trout were also more likely to pass at warmer temperatures, but this effect diminished above 15 °C. Passage was impeded at higher flows, through culverts with steep slopes, and those with deep downstream pools. This study provides insight on factors influencing brook trout capacity to pass culverts as well as a model to estimate passage success under various conditions, with an improved resolution and accuracy over existing approaches. It also presents methods that could be used to investigate passage success of other species, with implications for connectivity of the riverscape.

  18. 7. VIEW OF A DOUBLE CULVERT IN RAILROAD GRADE, LOOKING ...

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

    7. VIEW OF A DOUBLE CULVERT IN RAILROAD GRADE, LOOKING WEST. THIS CULVERT HAS BEEN IN PLACE SINCE 1933, WHEN IT WAS MARKED ON MONTANA DEPARTMENT OF HIGHWAYS AS-BUILT PLANS. IT LOOKS LIKE THE PIPE ON THE RIGHT (NORTH) IS NOT ORIGINAL. - Great Northern Railroad Bed, From Big Sandy to Verona, Fort Benton, Chouteau County, MT

  19. Special type culvert headwall, Culvert No. 124 Outlet, oblique view, ...

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

    Special type culvert headwall, Culvert No. 124 Outlet, oblique view, view to southwest - Route No. 1-Overton-Lake Mead Road, Culverts and Headwalls, 6 miles south of Overton, Overton, Clark County, NV

  20. Straight type culvert headwall, Culvert No. 105 Inlet, oblique view, ...

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

    Straight type culvert headwall, Culvert No. 105 Inlet, oblique view, view to northeast - Route No. 1-Overton-Lake Mead Road, Culverts and Headwalls, 6 miles south of Overton, Overton, Clark County, NV

  1. Special type culvert headwall, Culvert No. 109 Outlet, oblique view, ...

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

    Special type culvert headwall, Culvert No. 109 Outlet, oblique view, view to southeast - Route No. 1-Overton-Lake Mead Road, Culverts and Headwalls, 6 miles south of Overton, Overton, Clark County, NV

  2. 24. WEST CONFEDERATE AVENUE, DOUBLE CULVERT APPEARS TO BE "BOX", ...

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

    24. WEST CONFEDERATE AVENUE, DOUBLE CULVERT APPEARS TO BE "BOX", BUT IS PIPE WITH SQUARE HEAD WALL OPENING. NOTE ARCHED TOP STYLE USED BY CCC. VIEW SE. - Gettysburg National Military Park Tour Roads, Gettysburg, Adams County, PA

  3. North portal of Culvert No. 1308, High Germany Road Culvert, ...

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

    North portal of Culvert No. 1308, High Germany Road Culvert, seen from Bill's Place in Little Orleans, MD, looking southeast. - Western Maryland Railway, Cumberland Extension, Pearre to North Branch, from WM milepost 125 to 160, Pearre, Washington County, MD

  4. Culvert No. 1308, High Germany Road Culvert in Little Orleans, ...

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

    Culvert No. 1308, High Germany Road Culvert in Little Orleans, Maryland. Bill's Place in foreground, looking east. - Western Maryland Railway, Cumberland Extension, Pearre to North Branch, from WM milepost 125 to 160, Pearre, Washington County, MD

  5. 64. Paynes Creek Culvert. This concrete box culvert is a ...

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

    64. Paynes Creek Culvert. This concrete box culvert is a typical example of a concrete box culvert finished with rusticated stone. Its arches reflect the rigid frame structures. Looking west. - Blue Ridge Parkway, Between Shenandoah National Park & Great Smoky Mountains, Asheville, Buncombe County, NC

  6. Singing Corrugated Pipes.

    ERIC Educational Resources Information Center

    Cadwell, Louis H.

    1994-01-01

    This article describes different techniques used to measure air flow velocity. The two methods used were Crawford's Wastebasket and a video camera. The results were analyzed and compared to the air flow velocity predicted by Bernoulli's principle. (ZWH)

  7. Application of a multistate model to estimate culvert effects on movement of small fishes

    USGS Publications Warehouse

    Norman, J.R.; Hagler, M.M.; Freeman, Mary C.; Freeman, B.J.

    2009-01-01

    While it is widely acknowledged that culverted road-stream crossings may impede fish passage, effects of culverts on movement of nongame and small-bodied fishes have not been extensively studied and studies generally have not accounted for spatial variation in capture probabilities. We estimated probabilities for upstream and downstream movement of small (30-120 mm standard length) benthic and water column fishes across stream reaches with and without culverts at four road-stream crossings over a 4-6-week period. Movement and reach-specific capture probabilities were estimated using multistate capture-recapture models. Although none of the culverts were complete barriers to passage, only a bottomless-box culvert appeared to permit unrestricted upstream and downstream movements by benthic fishes based on model estimates of movement probabilities. At two box culverts that were perched above the water surface at base flow, observed movements were limited to water column fishes and to intervals when runoff from storm events raised water levels above the perched level. Only a single fish was observed to move through a partially embedded pipe culvert. Estimates for probabilities of movement over distances equal to at least the length of one culvert were low (e.g., generally ???0.03, estimated for 1-2-week intervals) and had wide 95% confidence intervals as a consequence of few observed movements to nonadjacent reaches. Estimates of capture probabilities varied among reaches by a factor of 2 to over 10, illustrating the importance of accounting for spatially variable capture rates when estimating movement probabilities with capture-recapture data. Longer-term studies are needed to evaluate temporal variability in stream fish passage at culverts (e.g., in relation to streamflow variability) and to thereby better quantify the degree of population fragmentation caused by road-stream crossings with culverts. ?? American Fisheries Society 2009.

  8. Acoustical studies on corrugated tubes

    NASA Astrophysics Data System (ADS)

    Balaguru, Rajavel

    Corrugated tubes and pipes offer greater global flexibility combined with local rigidity. They are used in numerous engineering applications such as vacuum cleaner hosing, air conditioning systems of aircraft and automobiles, HVAC control systems of heating ducts in buildings, compact heat exchangers, medical equipment and offshore gas and oil transportation flexible riser pipelines. Recently there has been a renewed research interest in analyzing the flow through a corrugated tube to understand the underlying mechanism of so called whistling, although the whistling in such a tube was identified in early twentieth century. The phenomenon of whistling in a corrugated tube is interesting because an airflow through a smooth walled tube of similar dimensions will not generate any whistling tones. Study of whistling in corrugated tubes is important because, it not only causes an undesirable noise problem but also results in flow-acoustic coupling. Such a coupling can cause significant structural vibrations due to flow-acoustic-structure interaction. This interaction would cause flow-induced vibrations that could result in severe damage to mechanical systems having corrugated tubes. In this research work, sound generation (whistling) in corrugated tubes due to airflow is analyzed using experimental as well as Computational Fluid Dynamics-Large Eddy Simulation (CFD-LES) techniques. Sound generation mechanisms resulting in whistling have been investigated. The whistling in terms of frequencies and sound pressure levels for different flow velocities are studied. The analytical and experimental studies are carried out to understand the influence of various parameters of corrugated tubes such as cavity length, cavity width, cavity depth, pitch, Reynolds numbers and number of corrugations. The results indicate that there is a good agreement between theoretically calculated, computationally predicted and experimentally measured whistling frequencies and sound pressure levels

  9. ECOLOGICAL CRITERIA FOR PRIORITIZATION OF CULVERT REPLACEMENT

    EPA Science Inventory

    Culvert passage issues are gaining national and international focus, because they are implicated in the decline of particular species and in the more general loss of biodiversity in freshwater ecosystems. In the Pacific Northwest, inadequate fish passage at culverts is recognized...

  10. User's guide to the culvert analysis program

    USGS Publications Warehouse

    Fulford, Janice M.

    1995-01-01

    This user's guide contains information on using the culvert analysis program (CAP). The procedure used is based on that presented in Techniques of Water- Resources Investigations of the United States Geological Survey, book 3, chapter A3, "Measurement of Peak Discharge at Culverts by Indirect Methods." The program uses input files that have formats compatible with those used by the Water-Surface Profile (WSPRO) program. The program can be used to compute rating surfaces or curves that describe the behavior of flow through a culvert or to compute discharges from measurements of upstream and downstream water-surface elevations.

  11. Birefringent corrugated waveguide

    DOEpatents

    Moeller, Charles P.

    1990-01-01

    A corrugated waveguide having a circular bore and noncircularly symmetric corrugations, and preferably elliptical corrugations, provides birefringence for rotation of polarization in the HE.sub.11 mode. The corrugated waveguide may be fabricated by cutting circular grooves on a lathe in a cylindrical tube or rod of aluminum of a diameter suitable for the bore of the waveguide, and then cutting an approximation to ellipses for the corrugations using a cutting radius R.sub.0 from the bore axis that is greater than the bore radius, and then making two circular cuts using a radius R.sub.1 less than R.sub.0 at centers +b and -b from the axis of the waveguide bore. Alternatively, stock for the mandrel may be formed with an elliptical transverse cross section, and then only the circular grooves need be cut on a lathe, leaving elliptical corrugations between the grooves. In either case, the mandrel is first electroplated and then dissolved leaving a corrugated waveguide with noncircularly symmetric corrugations. A transition waveguide is used that gradually varies from circular to elliptical corrugations to couple a circularly corrugated waveguide to an elliptically corrugated waveguide.

  12. Profiles in garbage: Corrugated boxes

    SciTech Connect

    Miller, C.

    1997-12-01

    Corrugated boxes (also known as old corrugated containers, or OCC) are used to ship products to factories, warehouses, retail stores, offices, and homes. The primary market for OCC is the paperboard industry, which uses OCC for corrugated medium, linerboard, recycled paperboard, and other paper products. In addition, 2.6 million tons of OCC were exported in 1996. OCC provided 37% of the scrap paper that was exported in 1996. Some corrugated boxes can be reused before recycling. Corrugated boxes are easily and highly recyclable. Large producers such as grocery store warehouses and factories have recycled their corrugated boxes for some time. If shredded properly, uncoated corrugated boxes are easily compostable.

  13. 21. Old Crosscut Canal, Indian School Road Culvert, Plan and ...

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

    21. Old Crosscut Canal, Indian School Road Culvert, Plan and Elevation, July 1974. See AZ-21-10 for photograph of the completed culvert. Source: city of Phoenix Engineering Department. - Old Crosscut Canal, North Side of Salt River, Phoenix, Maricopa County, AZ

  14. Fish Movement Ecology in High Gradient Headwater Streams: Its Relevance to Fish Passage Restoration through Stream Culvert Barriers

    USGS Publications Warehouse

    Hoffman, Robert L.; Dunham, Jason B.

    2007-01-01

    Executive Summary Restoration of fish passage through culvert barriers has emerged as a major issue in the Pacific Northwest and nationwide. The problem has many dimensions, including the huge number of potential barriers, uncertainty about which structures are actually barriers, the benefits and risks involved with restoration, and the financial costs and timelines. This report attempts to address what we call 'thinking outside of the pipe' in terms of fish passage information needs. This means understanding the value of each potential passage restoration project in the context of other possible projects, and to view individual restoration projects within a larger landscape of habitats and population processes. In this report we provide a brief review of some essential characteristics of animal movement and examples from a focal group of fishes in Washington State: salmon, trout, and char. While several other fishes and many other species use streams where culvert passage barriers may occur, it is the salmonids that are by far the most widespread and in most cases extending furthest into the headwaters of stream networks in Washington. We begin this report by outlining some basic characteristics of animal movement and then apply that foundation to the case of salmonid fishes. Next we consider the consequences of disrupting fish movement with human-constructed barriers, such as culverts. Finally, this body of evidence is summarized and we propose a short list of what we view as high priority information needs to support more effective restoration of fish passage through culverts.

  15. Corrugated waveguide monopulse feed

    NASA Astrophysics Data System (ADS)

    Elliott, R. D.; Clarricoats, P. J. B.

    1980-04-01

    The excitation coefficients of modes in a circular corrugated waveguide that arise when dominant modes are incident from a cluster of four square waveguides are calculated. Monopulse-like radiation patterns arise when modes in the input guides are appropriately phased. Factors influencing the crosspolar performance of the feed are discussed, and the dependence of the excitation coefficients on waveguide and junction parameters is predicted.

  16. Corrugation of roads

    NASA Astrophysics Data System (ADS)

    Both, Joseph A.; Hong, Daniel C.; Kurtze, Douglas A.

    2001-12-01

    We present a one dimensional model for the development of corrugations in roads subjected to compressive forces from a flux of cars. The cars are modeled as damped harmonic oscillators translating with constant horizontal velocity across the surface, and the road surface is subject to diffusive relaxation. We derive dimensionless coupled equations of motion for the positions of the cars and the road surface H( x, t), which contain two phenomenological variables: an effective diffusion constant Δ( H) that characterizes the relaxation of the road surface, and a function a( H) that characterizes the plasticity or erodibility of the road bed. Linear stability analysis shows that corrugations grow if the speed of the cars exceeds a critical value, which decreases if the flux of cars is increased. Modifying the model to enforce the simple fact that the normal force exerted by the road can never be negative seems to lead to restabilized, quasi-steady road shapes, in which the corrugation amplitude and phase velocity remain fixed.

  17. An Improved Method of Manufacturing Corrugated Boxes: Lateral Corrugator

    SciTech Connect

    Frank C. Murray Ph.D.; , Roman Popil Ph.D.; Michael Shaepe

    2008-12-18

    Paper physicists have known that a corrugated box constructed from outer liner sheets having a predominant fiber orientation aligned with the corrugating flute direction would have higher stiffness and crush resistance (per unit of fiber weight) than the conventional box construction. Such increased performance per unit of fiber weight could result in fiber reduction and energy savings for boxes having equivalent performance specifications. The goal of this project was to develop and demonstrate a commercially viable lateral corrugating process. This included designing and building a pilot lateral corrugator, testing and evaluating pilot machine made boxes, and developing a strategy for commercialization.

  18. Linear Corrugating - Final Technical Report

    SciTech Connect

    Lloyd Chapman

    2000-05-23

    Linear Corrugating is a process for the manufacture of corrugated containers in which the flutes of the corrugated medium are oriented in the Machine Direction (MD) of the several layers of paper used. Conversely, in the conventional corrugating process the flutes are oriented at right angles to the MD in the Cross Machine Direction (CD). Paper is stronger in MD than in CD. Therefore, boxes made using the Linear Corrugating process are significantly stronger-in the prime strength criteria, Box Compression Test (BCT) than boxes made conventionally. This means that using Linear Corrugating boxes can be manufactured to BCT equaling conventional boxes but containing 30% less fiber. The corrugated container industry is a large part of the U.S. economy, producing over 40 million tons annually. For such a large industry, the potential savings of Linear Corrugating are enormous. The grant for this project covered three phases in the development of the Linear Corrugating process: (1) Production and evaluation of corrugated boxes on commercial equipment to verify that boxes so manufactured would have enhanced BCT as proposed in the application; (2) Production and evaluation of corrugated boxes made on laboratory equipment using combined board from (1) above but having dual manufactures joints (glue joints). This box manufacturing method (Dual Joint) is proposed to overcome box perimeter limitations of the Linear Corrugating process; (3) Design, Construction, Operation and Evaluation of an engineering prototype machine to form flutes in corrugating medium in the MD of the paper. This operation is the central requirement of the Linear Corrugating process. Items I and II were successfully completed, showing predicted BCT increases from the Linear Corrugated boxes and significant strength improvement in the Dual Joint boxes. The Former was constructed and operated successfully using kraft linerboard as the forming medium. It was found that tensile strength and stretch

  19. 9. VIEW OF THE PRESSURE CULVERT STILLING BASIN, LOOKING NORTH. ...

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

    9. VIEW OF THE PRESSURE CULVERT STILLING BASIN, LOOKING NORTH. NOTE THE LEVEE TO THE RIGHT. - Wyoming Valley Flood Control System, Woodward Pumping Station, East of Toby Creek crossing by Erie-Lackawanna Railroad, Edwardsville, Luzerne County, PA

  20. 11. VIEW OF FLOOD GATE FOR THE PRESSURE CULVERT AND ...

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

    11. VIEW OF FLOOD GATE FOR THE PRESSURE CULVERT AND THE SOUTH AND EAST ELEVATIONS, LOOKING NORTHWEST. - Wyoming Valley Flood Control System, Woodward Pumping Station, East of Toby Creek crossing by Erie-Lackawanna Railroad, Edwardsville, Luzerne County, PA

  1. Contextual view showing drainage culvert in foreground boarding east side ...

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

    Contextual view showing drainage culvert in foreground boarding east side of knoll with eucalyptus windbreak. Camera facing 278" southwest. - Goerlitz House, 9893 Highland Avenue, Rancho Cucamonga, San Bernardino County, CA

  2. 9. STONE SLAB CULVERT UNDER CARRIAGE ROAD AT HORSESHOE CURVE ...

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

    9. STONE SLAB CULVERT UNDER CARRIAGE ROAD AT HORSESHOE CURVE NEAR GIANT SLIDE TRAIL MARKER ON AROUND-THE-MOUNTAIN LOOP. - Rockefeller Carriage Roads, Mount Desert Island, Bar Harbor, Hancock County, ME

  3. 22. photographer unknown 8 May 1935 EXCAVATION FOR MAIN CULVERT ...

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

    22. photographer unknown 8 May 1935 EXCAVATION FOR MAIN CULVERT AND LATERALS IN LOCK FLOOR. - Bonneville Project, Navigation Lock No. 1, Oregon shore of Columbia River near first Powerhouse, Bonneville, Multnomah County, OR

  4. Juniata Street Culvert. Havre de Grace, Hareford Co., MD. Sec. ...

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

    Juniata Street Culvert. Havre de Grace, Hareford Co., MD. Sec. 1201, MP 60.77. - Northeast Railroad Corridor, Amtrak route between District of Columbia/Maryland state line & Maryland/Delaware state line, Baltimore, Independent City, MD

  5. SEVERN RUN CULVERT. MAYFIELD, ANNE ARUNDEL CO., MD Sec. 1201, ...

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

    SEVERN RUN CULVERT. MAYFIELD, ANNE ARUNDEL CO., MD Sec. 1201, MP 112.17. - Northeast Railroad Corridor, Amtrak route between District of Columbia/Maryland state line & Maryland/Delaware state line, Baltimore, Independent City, MD

  6. South portal of Culvert No. 1508 in Old Town, Maryland, ...

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

    South portal of Culvert No. 1508 in Old Town, Maryland, looking north. - Western Maryland Railway, Cumberland Extension, Pearre to North Branch, from WM milepost 125 to 160, Pearre, Washington County, MD

  7. Feature 6, removed culvert north end to south very little ...

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

    Feature 6, removed culvert north end to south very little showing due to vegetation - Victory Highway, One Mile Segment West of West Wendover and South of Interstate 80, West Wendover, Elko County, NV

  8. 8. VIEW OF DOWNSTREAM OUTLET CULVERT AND WING RETAINING WALLS, ...

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

    8. VIEW OF DOWNSTREAM OUTLET CULVERT AND WING RETAINING WALLS, LOOKING NORTHWEST - High Mountain Dams in Upalco Unit, Twin Pots Dam, Ashley National Forest, 10.1 miles North of Mountain Home, Mountain Home, Duchesne County, UT

  9. Effect of corrugated characteristics on the liquid nitrogen temperature field of HTS cable

    NASA Astrophysics Data System (ADS)

    Li, Z. M.; Li, Y. X.; Zhao, Y. Q.; Gao, C.; Qiu, M.; Chen, G. F.; Gong, M. Q.; Wu, J. F.

    2014-01-01

    In the high temperature superconducting (HTS) cable system, liquid nitrogen is usually chosen to be the coolant because of its low saturation temperature and large latent heat of vaporization. Thus, it is very important for superconducting cables that the liquid nitrogen temperature field keeps stable. However, the cryostat is usually made of flexible corrugated pipes and multi-layer insulation materials. The characteristics (e.g. wave pitch and wave depth) of corrugated pipes may have an effect on the heat exchange between cable and liquid nitrogen, even the whole temperature field of liquid nitrogen. In this paper, a two-dimensional model for 30 m long HTS cable has been modified to analyze the effect of corrugated characteristics on the temperature field of liquid nitrogen. The liquid nitrogen temperature difference between the outlet and the inlet of passage gradually increases as the wave pitch of the corrugated tube decreases and the wave depth increases.

  10. Stacked Corrugated Horn Rings

    NASA Technical Reports Server (NTRS)

    Sosnowski, John B.

    2010-01-01

    This Brief describes a method of machining and assembly when the depth of corrugations far exceeds the width and conventional machining is not practical. The horn is divided into easily machined, individual rings with shoulders to control the depth. In this specific instance, each of the corrugations is identical in profile, and only differs in diameter and outer profile. The horn is segmented into rings that are cut with an interference fit (zero clearance with all machining errors biased toward contact). The interference faces can be cut with a reverse taper to increase the holding strength of the joint. The taper is a compromise between the interference fit and the clearance of the two faces during assembly. Each internal ring is dipped in liquid nitrogen, then nested in the previous, larger ring. The ring is rotated in the nest until the temperature of the two parts equalizes and the pieces lock together. The resulting assay is stable, strong, and has an internal finish that cannot be achieved through other methods.

  11. Dealing with uncertainty when assessing fish passage through culvert road crossings

    USGS Publications Warehouse

    Anderson, Gregory B.; Freeman, Mary C.; Freeman, Byron J.; Straight, Carrie A.; Hagler, Megan M.; Peterson, James T.

    2012-01-01

    Assessing the passage of aquatic organisms through culvert road crossings has become increasingly common in efforts to restore stream habitat. Several federal and state agencies and local stakeholders have adopted assessment approaches based on literature-derived criteria for culvert impassability. However, criteria differ and are typically specific to larger-bodied fishes. In an analysis to prioritize culverts for remediation to benefit imperiled, small-bodied fishes in the Upper Coosa River system in the southeastern United States, we assessed the sensitivity of prioritization to the use of differing but plausible criteria for culvert impassability. Using measurements at 256 road crossings, we assessed culvert impassability using four alternative criteria sets represented in Bayesian belief networks. Two criteria sets scored culverts as either passable or impassable based on alternative thresholds of culvert characteristics (outlet elevation, baseflow water velocity). Two additional criteria sets incorporated uncertainty concerning ability of small-bodied fishes to pass through culverts and estimated a probability of culvert impassability. To prioritize culverts for remediation, we combined estimated culvert impassability with culvert position in the stream network relative to other barriers to compute prospective gain in connected stream habitat for the target fish species. Although four culverts ranked highly for remediation regardless of which criteria were used to assess impassability, other culverts differed widely in priority depending on criteria. Our results emphasize the value of explicitly incorporating uncertainty into criteria underlying remediation decisions. Comparing outcomes among alternative, plausible criteria may also help to identify research most needed to narrow management uncertainty.

  12. Dealing With Uncertainty When Assessing Fish Passage Through Culvert Road Crossings

    NASA Astrophysics Data System (ADS)

    Anderson, Gregory B.; Freeman, Mary C.; Freeman, Byron J.; Straight, Carrie A.; Hagler, Megan M.; Peterson, James T.

    2012-09-01

    Assessing the passage of aquatic organisms through culvert road crossings has become increasingly common in efforts to restore stream habitat. Several federal and state agencies and local stakeholders have adopted assessment approaches based on literature-derived criteria for culvert impassability. However, criteria differ and are typically specific to larger-bodied fishes. In an analysis to prioritize culverts for remediation to benefit imperiled, small-bodied fishes in the Upper Coosa River system in the southeastern United States, we assessed the sensitivity of prioritization to the use of differing but plausible criteria for culvert impassability. Using measurements at 256 road crossings, we assessed culvert impassability using four alternative criteria sets represented in Bayesian belief networks. Two criteria sets scored culverts as either passable or impassable based on alternative thresholds of culvert characteristics (outlet elevation, baseflow water velocity). Two additional criteria sets incorporated uncertainty concerning ability of small-bodied fishes to pass through culverts and estimated a probability of culvert impassability. To prioritize culverts for remediation, we combined estimated culvert impassability with culvert position in the stream network relative to other barriers to compute prospective gain in connected stream habitat for the target fish species. Although four culverts ranked highly for remediation regardless of which criteria were used to assess impassability, other culverts differed widely in priority depending on criteria. Our results emphasize the value of explicitly incorporating uncertainty into criteria underlying remediation decisions. Comparing outcomes among alternative, plausible criteria may also help to identify research most needed to narrow management uncertainty.

  13. Improved design and construction of large-span culverts

    NASA Astrophysics Data System (ADS)

    Webb, Mark Cottington

    A comprehensive review was made of the design and construction of flexible metal and rigid reinforced concrete large-span culverts, past documented field experience of monitored culvert performance, and culvert failures. Full-scale field testing of a flexible metal and a reinforced concrete large-span culvert was conducted and the results compared with finite element computer analyses. Based on this work recommendations for improved design and construction of large-span culverts were developed. The review of metal culvert design and construction practice revealed numerous differences among current methods as well as deficiencies. Proposed design limit states were identified and discussed for improved practice. An improved earth load thrust prediction model was developed based on past analytical work considering the flexural rigidity of the structure relative to the surrounding soil, in addition to other factors. The design curves for arching factors were extended to cover a wider range of structural backfill width conditions and shallower burial. Also, a proposed construction procedure was outlined to control construction moments based on deflection limits as a function of the expected level of construction control. None of the existing methods explicitly deals with large-span reinforced concrete culvert design and construction practice. Therefore, a proposed design approach for these culverts was outlined. Construction practice was based on recommendations from the manufacturers. The review of failure cases showed that most failures of large-span metal culverts occurred as a result of poor backfill procedures and/or poor backfill material selection. Other causes were excessive construction loads and invert uplift. Excessive deformation was the most common limit state reached before or at failure. Furthermore, significant variations in structural response may occur over time after construction. Therefore, better construction provisions and control are needed

  14. Remaining Sites Verification Package for the 100-F-50 Stormwater Runoff Culvert, Waste Site Reclassification Form 2007-001

    SciTech Connect

    J. M. Capron

    2008-04-15

    The 100-F-50 waste site, part of the 100-FR-2 Operable Unit, is a steel stormwater runoff culvert that runs between two railroad grades in the south-central portion of the 100-F Area. The culvert exiting the west side of the railroad grade is mostly encased in concrete and surrounded by a concrete stormwater collection depression partially filled with soil and vegetation. The drain pipe exiting the east side of the railroad grade embankment is partially filled with soil and rocks. The 100-F-50 stormwater diversion culvert confirmatory sampling results support a reclassification of this site to no action. The current site conditions achieve the remedial action objectives and corresponding remedial action goals established in the Remaining Sites ROD. The results of confirmatory sampling show that residual contaminant concentrations do not preclude any future uses and allow for unrestricted use of shallow zone soils. The results also demonstrate that residual contaminant concentrations are protective of groundwater and the Columbia River.

  15. Feasibility of culvert IED detection using thermal neutron activation

    NASA Astrophysics Data System (ADS)

    Faust, Anthony A.; McFee, John E.; Clifford, Edward T. H.; Andrews, Hugh Robert; Mosquera, Cristian; Roberts, William C.

    2012-06-01

    Bulk explosives hidden in culverts pose a serious threat to the Canadian and allied armies. Culverts provide an opportunity to conceal insurgent activity, avoid the need for detectable surface disturbances, and limit the applicability of conventional sub-surface sensing techniques. Further, in spite of the large masses of explosives that can be employed, the large sensor{target separation makes detection of the bulk explosive content challeng- ing. Defence R&D Canada { Sueld and Bubble Technology Industries have been developing thermal neutron activation (TNA) sensors for detection of buried bulk explosives for over 15 years. The next generation TNA sensor, known as TNA2, incorporates a number of improvements that allow for increased sensor-to-target dis- tances, making it potentially feasible to detect large improvised explosive devices (IEDs) in culverts using TNA. Experiments to determine the ability of TNA2 to detect improvised explosive devices in culverts are described, and the resulting signal levels observed for relevant quantities of explosives are presented. Observations conrm that bulk explosives detection using TNA against a culvert-IED is possible, with large charges posing a detection challenge at least as dicult as that of a deeply buried anti-tank landmine. Because of the prototype nature of the TNA sensor used, it is not yet possible to make denitive statements about the absolute sensitivity or detection time. Further investigation is warranted.

  16. Shape optimization of corrugated airfoils

    NASA Astrophysics Data System (ADS)

    Jain, Sambhav; Bhatt, Varun Dhananjay; Mittal, Sanjay

    2015-12-01

    The effect of corrugations on the aerodynamic performance of a Mueller C4 airfoil, placed at a 5° angle of attack and Re=10{,}000, is investigated. A stabilized finite element method is employed to solve the incompressible flow equations in two dimensions. A novel parameterization scheme is proposed that enables representation of corrugations on the surface of the airfoil, and their spontaneous appearance in the shape optimization loop, if indeed they improve aerodynamic performance. Computations are carried out for different location and number of corrugations, while holding their height fixed. The first corrugation causes an increase in lift and drag. Each of the later corrugations leads to a reduction in drag. Shape optimization of the Mueller C4 airfoil is carried out using various objective functions and optimization strategies, based on controlling airfoil thickness and camber. One of the optimal shapes leads to 50 % increase in lift coefficient and 23 % increase in aerodynamic efficiency compared to the Mueller C4 airfoil.

  17. 7. VIEW OF WEAPONS DELIVERY ROAD CULVERT OF LOWER DIAGONAL ...

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

    7. VIEW OF WEAPONS DELIVERY ROAD CULVERT OF LOWER DIAGONAL NO. 1 DRAIN, LOOKING 522 EAST OF NORTH. - Truckee-Carson Irrigation District, Lower Diagonal No. 1 Drain, Bounded by West Gate Road & Weapons Delivery Road, Naval Air Station Fallon, Fallon, Churchill County, NV

  18. 5. VIEW OF WEST GATE ROAD CULVERT OF LOWER DIAGONAL ...

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

    5. VIEW OF WEST GATE ROAD CULVERT OF LOWER DIAGONAL NO. 1 DRAIN, LOOKING 323' EAST OF NORTH. - Truckee-Carson Irrigation District, Lower Diagonal No. 1 Drain, Bounded by West Gate Road & Weapons Delivery Road, Naval Air Station Fallon, Fallon, Churchill County, NV

  19. 6. VIEW OF WEST GATE ROAD CULVERT OF LOWER DIAGONAL ...

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

    6. VIEW OF WEST GATE ROAD CULVERT OF LOWER DIAGONAL NO. 1 DRAIN, LOOKING 2502 EAST OF NORTH. - Truckee-Carson Irrigation District, Lower Diagonal No. 1 Drain, Bounded by West Gate Road & Weapons Delivery Road, Naval Air Station Fallon, Fallon, Churchill County, NV

  20. DETAIL OF WING WALL ON OUTLET SIDE OF CULVERT. NOTE ...

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

    DETAIL OF WING WALL ON OUTLET SIDE OF CULVERT. NOTE THE INCLUSIONS IN THE CONCRETE. OBLIQUE VIEW TO THE SOUTH-SOUTHWEST. 21 - Burlington Northern Santa Fe Railroad, Cajon Subdivision, Structure 58.1X, Between Cajon Summit and Keenbrook, Devore, San Bernardino County, CA

  1. 35. Photo of concrete arch culvert constructed by Puget Sound ...

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

    35. Photo of concrete arch culvert constructed by Puget Sound Construction Company, 1911, for the Northern Pacific Railroad, over flume. Photo by Brian C. Morris, Puget Power, 1989. - Puget Sound Power & Light Company, White River Hydroelectric Project, 600 North River Avenue, Dieringer, Pierce County, WA

  2. Flood magnitude and frequency of Main Ditch at the culvert on New Jersey Route 44 and at the Conrail culvert downstream, West Deptford Township, Gloucester County, New Jersey

    USGS Publications Warehouse

    Barringer, Thomas

    1996-01-01

    The magnitude and frequency of floods at Main Ditch at the culvert on New Jersey Route 44 at milepost 8.3 and at the Conrail culvert 0.21 miles downstream, in West Deptford Township, New Jersey, were determined by using the New Jersey Department of Environmental Protection Special Report 38 method. Flood-magnitude and -frequency estimates, as well as drainage-basin characteristics, are included in this report. The 100-year-flood estimates are 285 cubic feet per second at the culvert on New Jersey Route 44 and 345 cubic feet per second at the Conrail culvert.

  3. A Simple Experiment to Explore Standing Waves in a Flexible Corrugated Sound Tube

    ERIC Educational Resources Information Center

    Amorim, Maria Eva; Sousa, Teresa Delmira; Carvalho, P. Simeao; Sousa, Adriano Sampaioe

    2011-01-01

    Sound tubes, pipes, and singing rods are used as musical instruments and as toys to perform amusing experiments. In particular, corrugated tubes present unique characteristics with respect to the sounds they can produce; that is why they have been studied so intensively, both at theoretical and experimental levels. Experimental studies usually…

  4. Culvert Analysis Program Graphical User Interface 1.0--A preprocessing and postprocessing tool for estimating flow through culvert

    USGS Publications Warehouse

    Bradley, D. Nathan

    2013-01-01

    The peak discharge of a flood can be estimated from the elevation of high-water marks near the inlet and outlet of a culvert after the flood has occurred. This type of discharge estimate is called an “indirect measurement” because it relies on evidence left behind by the flood, such as high-water marks on trees or buildings. When combined with the cross-sectional geometry of the channel upstream from the culvert and the culvert size, shape, roughness, and orientation, the high-water marks define a water-surface profile that can be used to estimate the peak discharge by using the methods described by Bodhaine (1968). This type of measurement is in contrast to a “direct” measurement of discharge made during the flood where cross-sectional area is measured and a current meter or acoustic equipment is used to measure the water velocity. When a direct discharge measurement cannot be made at a streamgage during high flows because of logistics or safety reasons, an indirect measurement of a peak discharge is useful for defining the high-flow section of the stage-discharge relation (rating curve) at the streamgage, resulting in more accurate computation of high flows. The Culvert Analysis Program (CAP) (Fulford, 1998) is a command-line program written in Fortran for computing peak discharges and culvert rating surfaces or curves. CAP reads input data from a formatted text file and prints results to another formatted text file. Preparing and correctly formatting the input file may be time-consuming and prone to errors. This document describes the CAP graphical user interface (GUI)—a modern, cross-platform, menu-driven application that prepares the CAP input file, executes the program, and helps the user interpret the output

  5. Turtles and culverts, and alternative energy development: an unreported but potentially significant mortality threat to the desert tortoise (Gopherus agassizii)

    USGS Publications Warehouse

    Lovich, J.E.; Ennen, J.R.; Madrak, S.; Grover, B.

    2011-01-01

    Culverts are often used to increase the permeability of roaded landscapes for wildlife, including turtles. Although the benefits of culverts as safe passages for turtles are well documented, under some conditions culverts can entrap them and cause mortality. Here we report a culvert-related mortality in the federally threatened desert tortoise (Gopherus agassizii) at a wind energy facility in California and offer simple recommendations to mitigate the negative effects of culverts for wildlife in general.

  6. Strain variation in corrugated graphene

    NASA Astrophysics Data System (ADS)

    Wang, Xuanye; Tantiwanichapan, Khwanchai; Christopher, Jason; Paiella, Roberto; Swan, Anna

    2015-03-01

    Raman spectroscopy is a powerful non-destructive technique for analyzing strain in graphene. Recently there has been interest in making corrugated graphene devices with varying spatial wavelengths Λ for plasmonic and THz applications. Transferring graphene onto corrugated substrates introduces strain, which if there was perfect clamping (high fraction) would cause a periodic strain variation. However, the strain variation for pattern size smaller than the diffraction limit λ makes it hard to precisely model the strain distribution. Here we present a detailed study on how strain varies in corrugated graphene with sub-diffraction limit periodicity Λ < λ. Mechanically exfoliated graphene was deposited onto sinusoidal shape silicon dioxide gratings with Λ=400 nm period using the pick and place transfer technique. We observed that the graphene is not rigidly clamped, but partially slides to relieve the strain. We model the linewidth variation to extract the local strain variation as well as the sliding in the presence of charge puddling in graphene. The method gives us a better understanding on graphene slippage and strain distribution in graphene on a corrugated substrate with sub-diffraction limit spatial period.

  7. Culvert analysis program for indirect measurement of discharge

    USGS Publications Warehouse

    Fulford, Janice M.; ,

    1993-01-01

    A program based on the U.S. Geological Survey (USGS) methods for indirectly computing peak discharges through culverts allows users to employ input data formats used by the water surface profile program (WSPRO). The program can be used to compute discharge rating surfaces or curves that describe the behavior of flow through a particular culvert or to compute discharges from measurements of upstream of the gradually varied flow equations and has been adapted slightly to provide solutions that minimize the need for the user to determine between different flow regimes. The program source is written in Fortran 77 and has been run on mini-computers and personal computers. The program does not use or require graphics capability, a color monitor, or a mouse.

  8. 24. CULVERT WITH CONCRETE HEADWALL AND SIDEWALLS CARRYING THE LATERAL ...

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

    24. CULVERT WITH CONCRETE HEADWALL AND SIDEWALLS CARRYING THE LATERAL UNDER 8TH AVENUE. - Highline Canal, Sand Creek Lateral, Beginning at intersection of Peoria Street & Highline Canal in Arapahoe County (City of Aurora), Sand Creek lateral Extends 15 miles Northerly through Araphoe County, City & County of Denver, & Adams County to its end point, approximately 1/4 mile Southest of intersectioin of D Street & Ninth Avenue in Adams County (Rocky Mountain Arsenal, Commerce City Vicinity), Commerce City, Adams County, CO

  9. Corrugated Membrane Fuel Cell Structures

    SciTech Connect

    Grot, Stephen

    2013-09-30

    One of the most challenging aspects of traditional PEM fuel cell stacks is the difficulty achieving the platinum catalyst utilization target of 0.2 gPt/kWe set forth by the DOE. Good catalyst utilization can be achieved with state-of-the-art catalyst coated membranes (CCM) when low catalyst loadings (<0.3 mg/cm2) are used at a low current. However, when low platinum loadings are used, the peak power density is lower than conventional loadings, requiring a larger total active area and a larger bipolar plate. This results in a lower overall stack power density not meeting the DOE target. By corrugating the fuel cell membrane electrode structure, Ion Power?s goal is to realize both the Pt utilization targets as well as the power density targets of the DOE. This will be achieved by demonstrating a fuel cell single cell (50 cm2) with a twofold increase in the membrane active area over the geometric area of the cell by corrugating the MEA structure. The corrugating structure must be able to demonstrate the target properties of < 10 mOhm-cm2 electrical resistance at > 20 psi compressive strength over the active area, in combination with offering at least 80% of power density that can be achieved by using the same MEA in a flat plate structure. Corrugated membrane fuel cell structures also have the potential to meet DOE power density targets by essentially packaging more membrane area into the same fuel cell volume as compared to conventional stack constructions.

  10. A Simple Experiment to Explore Standing Waves in a Flexible Corrugated Sound Tube

    NASA Astrophysics Data System (ADS)

    Amorim, Maria Eva; Sousa, Teresa Delmira; Carvalho, P. Simeão; Sousa, Adriano Sampaioe

    2011-09-01

    Sound tubes, pipes, and singing rods are used as musical instruments and as toys to perform amusing experiments. In particular, corrugated tubes present unique characteristics with respect to the sounds they can produce; that is why they have been studied so intensively, both at theoretical and experimental levels.1-4 Experimental studies usually involve expensive and sophisticated equipment that is out of reach of school laboratory facilities.3-6 In this paper we show how to investigate quantitatively the sounds produced by a flexible sound tube corrugated on the inside by using educational equipment readily available in school laboratories, such as the oscilloscope, the microphone, the anemometer, and the air pump. We show that it is possible for students to study the discontinuous spectrum of sounds produced by a flexible corrugated tube and go even further, computing the speed of sound in air with a simple experimental procedure.

  11. 6. VIEW OF A RUSTED, HEAVYGAUGE METAL CULVERT (TY31776) PLACED ...

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

    6. VIEW OF A RUSTED, HEAVY-GAUGE METAL CULVERT (TY-3177-6) PLACED AT A SMALL DRAW WHERE KINGS CANYON ROAD WILL BE INSLOPED AND THE CULVERT WILL BE REMOVED. LOCATED AT MILEPOST 0.05 (ACCORDING TO THE ARCHAEOLOGICAL SITE RECORD FOR TY-3177). FACING SOUTH 76ø WEST (256ø). - Kings Canyon Road, Carson City, Carson City, NV

  12. C&O Canal Fifteen Mile Creek Culvert in foreground, south portal ...

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

    C&O Canal Fifteen Mile Creek Culvert in foreground, south portal of Western Maryland's Fifteen Mile Creek Culvert in rear, looking west. - Western Maryland Railway, Cumberland Extension, Pearre to North Branch, from WM milepost 125 to 160, Pearre, Washington County, MD

  13. A parametric study of cut-off corrugated surface properties

    NASA Technical Reports Server (NTRS)

    Mentzer, C. A.; Peters, L., Jr.

    1973-01-01

    Corrugated horns involve a junction between the corrugated surface and a conducting groundplane. Proper horn design requires an understanding of the electromagnetic properties of the corrugated surface and this junction. Therefore, an integral equation solution has been used to study the influence of corrugation density and shape on the power loss. Surface current, and the scattering from a groundplane-corrugated surface junction. Both square and vee shape corrugations have been considered over the range of corrugation depths where the surface acts as a cut-off corrugated surface.

  14. Biaxially corrugated flexible sheet material

    DOEpatents

    Schmertz, John C.

    1991-04-16

    A flexible biaxially corrugated sheet material is formed from a plurality of identical trapezium segments which are arranged in a plurality of long strips a single segment wide. Adjacent strips are mirror images of each other and connected along adjoining sides with the angles of the four corners of adjacent segments being alternately less than 360.degree. and greater than 360.degree. along the length of a strip such that the sheet material has an undulating configuration, and is inherently curved and cannot lie in a flat plane.

  15. Movement and survival of an amphibian in relation to sediment and culvert design

    USGS Publications Warehouse

    Honeycutt, R.K; Lowe, W.H.; Hossack, Blake R.

    2016-01-01

    Habitat disturbance from stream culverts can affect aquatic organisms by increasing sedimentation or forming barriers to movement. Land managers are replacing many culverts to reduce these negative effects, primarily for stream fishes. However, these management actions are likely to have broad implications for many organisms, including amphibians in small streams. To assess the effects of culverts on movement and survival of the Idaho giant salamander (Dicamptodon aterrimus), we used capture-mark-recapture surveys and measured sediment in streams with 2 culvert types (i.e., unimproved culverts, improved culverts) and in streams without culverts (i.e., reference streams). We predicted culverts would increase stream sediment levels, limit movement, and reduce survival of Idaho giant salamanders. We also determined the effect of sediment levels on survival of salamanders because although sediment is often associated with distribution and abundance of stream amphibians, links with vital rates remain unclear. To estimate survival, we used a spatial Cormack–Jolly–Seber (CJS) model that explicitly incorporated information on movement, eliminating bias in apparent survival estimated from traditional (i.e., non-spatial) CJS models caused by permanent emigration beyond the study area. To demonstrate the importance of using spatial data in studies of wildlife populations, we compared estimates from the spatial CJS to estimates of apparent survival from a traditional CJS model. Although high levels of sediment reduced survival of salamanders, culvert type was unrelated to sediment levels or true survival of salamanders. Across all streams, we documented only 15 movement events between study reaches. All movement events were downstream, and they occurred disproportionately in 1 stream, which precluded measuring the effect of culvert design on movement. Although movement was low overall, the variance among streams was high enough to bias estimates of apparent survival

  16. MONITORING CULVERT PASSAGE OF JUVENILE SALMONIDS WITH PIT TAGS AND STATIONARY AND PORTABLE PIT-TAG READERS

    EPA Science Inventory

    Federal land management agencies in the PNW face increasing pressure to replace culverts that do not pass all life history stages of anadromous salmon and trout. Prioritization of culverts for replacement is often based on the physical parameters of culverts, and not on how fish...

  17. Mechanical Analysis of Trapezoidal Corrugated Composite Skins

    NASA Astrophysics Data System (ADS)

    Ghabezi, P.; Golzar, M.

    2013-08-01

    Using of the corrugated skins and morphing technology is a good idea to provide the desired performance and improve aerodynamic efficiency. Corrugated structures and skins are flexible in the direction of corrugation and stiff in the transverse direction. In this paper a simple analytical model for the effective stiffness of the trapezoidal corrugated composites is developed in symmetrical and unsymmetrical lay-up. The elongation and effective stiffness in longitudinal and transverse directions of trapezoidal corrugated skins and flat composites are extracted using strain energy and Castiglione's theorem. Various dimensions of trapezoidal element for unidirectional and plain woven fabrics of E-glass/Epoxy are investigated. Trapezoidal corrugated composites were modelled by commercial FEM software ABAQUS and compared to analytical model. Analytical model is validated by experimental results from bending and tensile tests. Finally, load-displacement curves in the tensile and bending tests are studied and their different stages of behavior are identified. Results of FEM, experimental and analytical simulation show that how the corrugated composite skins can afford obviously larger deformation than the flat one and they are good solution to use in the morphing applications.

  18. Assessing Juvenile Salmonid Passage Through Culverts: Field Research in Support of Protocol Development

    SciTech Connect

    Williams, Greg D.; Evans, Nathan R.; Pearson, Walter H.; Southard, John A.

    2001-10-30

    The primary goal of our research this spring/ summer was to refine techniques and examine scenarios under which a standardized protocol could be applied to assess juvenile coho salmon (O. kisutch) passage through road culverts. Field evaluations focused on capture-mark- recapture methods that allowed analysis of fish movement patterns, estimates of culvert passability, and potential identification of cues inducing these movements. At this stage, 0+ age coho salmon fry 30 mm to 65 mm long (fork length) were the species and age class of interest. Ultimately, the protocol will provide rapid, statistically rigorous methods for trained personnel to perform standardized biological assessments of culvert passability to a number of juvenile salmon species. Questions to be addressed by the research include the following: ? Do hydraulic structures such as culverts restrict habitat for juvenile salmonids? ? How do existing culverts and retrofits perform relative to juvenile salmonid passage? ? Do some culvert characteristics and hydraulic conditions provide better passage than others? ? Does the culvert represent a barrier to certain size classes of fish? Recommendations addressed issues of study site selection, initial capture, marking, recapture/observations, and estimating movement.

  19. Corrugated cover plate for flat plate collector

    DOEpatents

    Hollands, K. G. Terry; Sibbitt, Bruce

    1978-01-01

    A flat plate radiant energy collector is providing having a transparent cover. The cover has a V-corrugated shape which reduces the amount of energy reflected by the cover away from the flat plate absorber of the collector.

  20. Method and apparatus for corrugating strips

    DOEpatents

    Day, Jack R.; Curtis, Charles H.

    1983-01-01

    The invention relates to a method and a machine for transversely corrugating a continuous strip of metallic foil. The product foil comprises a succession of alternately disposed corrugations, each defining in cross section, a major segment of a circle. The foil to be corrugated is positioned to extend within a vertical passage in the machine. The walls of the passage are heated to promote the desired deformation of the foil. Foil-deforming rollers are alternately passed obliquely across the passage to respectively engage transverse sections of the foil. The rollers and their respective section of deformed foil comprise a stacked assembly which is moved incrementally through the heated passageway. As the assembly emerges from the passageway, the rollers spill from the corrugated foil and are recovered for re-use.

  1. Method and apparatus for corrugating strips

    DOEpatents

    Day, J.R.; Curtis, C.H.

    1981-10-27

    The invention relates to a method and a machine for transversely corrugating a continuous strip of metallic foil. The product foil comprises a succession of alternately disposed corrugations, each defining in a cross section, a major segment of a circle. The foil to be corrugated is positioned to extend within a vertical passage in the machine. The walls of the passage are heated to promote the desired deformation of the foil. Foil-deforming rollers are alternately passed obliquely across the passage to respectively engage transverse sections of the foil. The rollers and their respective section of deformed foil comprise a stacked assembly which is moved incrementally through the heated passageway. As the assembly emerges from the passageway, the rollers spill from the corrugated foil and are recovered for re-use.

  2. Evolutionary design of corrugated horn antennas

    NASA Technical Reports Server (NTRS)

    Hoorfar, F.; Manshadi, V.; Jamnejad, A.

    2002-01-01

    An evolutionary progranirnitzg (EP) algorithm is used to optimize pattern of a corrugated circularhorn subject to various constraints on return loss and antenna beamwidth and pattern circularity and low crosspolarization. The EP algorithm uses a Gaussian mutation operator. Examples on design synthesis of a 45 section corrugated horn, with a total of 90 optimization parameters, are presented. The results show excellent and efficient optimization of the desired horn parameters.

  3. Unit 3, STA. 158+40 RB, Hinckson Run culvert context ...

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

    Unit 3, STA. 158+40 RB, Hinckson Run culvert context - Johnstown Local Flood Protection Project, Beginning on Conemaugh River approx 3.8 miles downstream from confluence of Little Conemaugh & Stony Creek Rivers at Johnstown, Johnstown, Cambria County, PA

  4. Credit PSR. View looks northwest (318°) at concrete culvert wings ...

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

    Credit PSR. View looks northwest (318°) at concrete culvert wings from which effluents from Imhoff Tank in background emerged into open sewage canal - Edwards Air Force Base, North Base, Imhoff Tank, Southwest of E Street, Boron, Kern County, CA

  5. Where have all the caddis gone? The role of culverts, and spiders

    NASA Astrophysics Data System (ADS)

    Harding, J. S.; Neumegen, R. E.; van den Braak, I. L.

    2005-05-01

    Restoration of a 1.5 km urban stream over the past five years has led to surprisingly slow improvement in benthic communities. Analysis of benthic invertebrates at six sites longitudinally showed a marked decline in caddisfly diversity and abundance upstream. This decline could not be adequately explained by changes in water quality, or in-stream physical conditions. Extensive adult trapping on multiple sites on three urban streams has shown that main roads with culverts act as barriers to the upstream flight of adult caddisflies. When adult caddis encounter a road culvert, some are distracted by the surrounding urban conditions (e.g. street lights), and only 30-50% enter the culvert. Of these, about 10-30% do not reach the upstream exit falling prey to spiders or distracted by confounding flight cues. Experimental removal of spiders and webs from three culverts showed an increase in the proportion of caddis exiting upstream. Other confounding effects on caddisflies within the culvert might include light, humidity and temperature gradients. Our results indicate that barriers to adult dispersal and colonisation, such as road culverts and confusing urban habitats, may markedly limit the recovery of urban stream communities.

  6. Flood magnitude and frequency of Little Mantual Creek at the culvert at milepost 7.8 on New Jersey Route 44, and at the Conrail culvert 0.20 miles downstream, West Deptford Township, Gloucester County, New Jersey

    USGS Publications Warehouse

    Barringer, Thomas

    1996-01-01

    The magnitude and frequency of floods at Little Mantua Creek at the culvert on New Jersey Route 44 at milepost 7.8 and at the Conrail culvert 0.20 miles downstream, in West Deptford Township, New Jersey, were determined by using the New Jersey Department of Environmental Protection Special Report 38 method. Flood-magnitude and -frequency estimates, as well as drainage-basin characteristics, are included in this report. The 100-year-flood estimates are 249 cubic feet per second at the culvert on New Jersey Route 44, and 243 cubic feet per second at the Conrail culvert.

  7. Estimates for Pu-239 loadings in burial ground culverts based on fast/slow neutron measurements

    SciTech Connect

    Winn, W.G.; Hochel, R.C.; Hofstetter, K.J.; Sigg, R.A.

    1989-08-15

    This report provides guideline estimates for Pu-239 mass loadings in selected burial ground culverts. The relatively high recorded Pu-239 contents of these culverts have been appraised as suspect relative to criticality concerns, because they were assayed only with the solid waste monitor (SWM) per gamma-ray counting. After 1985, subsequent waste was also assayed with the neutron coincidence counter (NCC), and a comparison of the assay methods showed that the NCC generally yielded higher assays than the SWM. These higher NCC readings signaled a need to conduct non-destructive/non-intrusive nuclear interrogations of these culverts, and a technical team conducted scoping measurements to illustrate potential assay methods based on neutron and/or gamma counting. A fast/slow neutron method has been developed to estimate the Pu-239 in the culverts. In addition, loading records include the SWM assays of all Pu-239 cuts of some of the culvert drums and these data are useful in estimating the corresponding NCC drum assays from NCC vs SWM data. Together, these methods yield predictions based on direct measurements and statistical inference.

  8. Guided Waves Attenuation in Water Immersed Corrugated Plates

    NASA Astrophysics Data System (ADS)

    Meier, Dominique; Franklin, Hervé; Izbicki, Jean Louis; Predoi, Mihai; Rousseau, Martine

    Influences of surface corrugations on the propagation of guided waves along an immersed elastic plate are investigated. The Finite Elements Method is used to compute the reflected and transmitted pressure fields for oblique incident plane harmonic waves in a selected frequency range. The effects of corrugations can also be accounted by means of a rheological model. The corrugated surface is then modeled by using modified boundary conditions at the liquid - corrugated plate interface. In this condition a parameter is introduced that can be evaluated by a fit procedure between the analytical solutions of modal resonance peaks and the FEM results for the corrugated plate.

  9. Surface-Water Exchange through Culverts beneath State Road 9336 within Everglades National Park, 2004-05

    USGS Publications Warehouse

    Schaffranek, Raymond W.; Stewart, Marc A.; Nowacki, Daniel J.

    2008-01-01

    The U.S. Geological Survey collected hydrologic data between June 2004 and December 2005 to investigate the temporal and spatial nature of flow exchanges through culverts beneath State Road 9336 within Everglades National Park. Continuous data collected during the study measured flow velocity, water level, salinity, conductivity, and water-temperature in or near seven culverts between Pa-hay-okee Overlook access road and Nine Mile Pond. The two culverts east of Pa-hay-okee Overlook access road flowed into Taylor Slough Basin from 87 to 96 percent of the study period, whereas flows through five culverts between Pa-hay-okee Overlook access road and Nine Mile Pond flowed into Shark River Slough Basin from 70 to 99 percent of the study period. Synoptic flow discharges measured at all culverts during three intensive field efforts revealed a net discharge into Taylor Slough Basin from Shark River Slough Basin through culverts between Royal Palm Road and Pa-hay-okee Overlook access road, and into Shark River Slough Basin from Taylor Slough Basin through culverts between Pa-hay-okee Overlook access road and Nine Mile Pond. Data collected during the study and presented in this report provided additional knowledge of the magnitude, direction, and nature of flow exchanges through the road culverts.

  10. Dynamic test of a corrugated steel keyworker blast shelter MISTY PICTURE. Final report

    SciTech Connect

    Holmes, R.L.; Slawson, T.R.; Harris, A.L.

    1987-11-01

    The 18-man blast shelter was tested dynamically on May 14, 1987 in the MISTY PICTURE event at White Sands Missile Range, NM. The main section of the shelter was fabricated from a 9-foot-diameter, 27.5-foot-long section of 10-gage, galvanized, corrugated steel culvert. The shelter included a vertical entryway and air intake and exhaust stacks. The shelter design was found to be conservative during a previous 50-psi validation test, and some constructibility problems were encountered with the entryway-to-shelter connections. This test was conducted to validate the modifications made to the shelter design. The modifications were made to reduce construction costs and improve constructibility. Primary modifications included: replacing the stiffened endwalls with lighter-weight unstiffened plates, connecting the entryway to an endwall rather than to the main section of the shelter, and the inclusion of an emergency exit. The structure was located at the anticipated 200-psi peak overpressure level. Post-test inspection revealed that the main section of the shelter suffered very little damage during the test. Due to the failure of the emergency exit cover plate, it was necessary to determine if enough pressure entered the shelter to affect its structural response. This test also investigated the shock environment inside the shelter.

  11. Corrugation of Relativistic Magnetized Shock Waves

    NASA Astrophysics Data System (ADS)

    Lemoine, Martin; Ramos, Oscar; Gremillet, Laurent

    2016-08-01

    As a shock front interacts with turbulence it develops corrugation, which induces outgoing wave modes in the downstream plasma. For a fast shock wave, the incoming wave modes can either be fast magnetosonic waves originating downstream, outrunning the shock, or eigenmodes of the upstream plasma drifting through the shock. Using linear perturbation theory in relativistic MHD, this paper provides a general analysis of the corrugation of relativistic magnetized fast shock waves resulting from their interaction with small amplitude disturbances. Transfer functions characterizing the linear response for each of the outgoing modes are calculated as a function of the magnetization of the upstream medium and as a function of the nature of the incoming wave. Interestingly, if the latter is an eigenmode of the upstream plasma, we find that there exists a resonance at which the (linear) response of the shock becomes large or even diverges. This result may have profound consequences on the phenomenology of astrophysical relativistic magnetized shock waves.

  12. Plasmonic corrugated cylinder-cone terahertz probe.

    PubMed

    Yao, Haizi; Zhong, Shuncong

    2014-08-01

    The spoof surface plasmon polariton (SPP) effect on the electromagnetic field distribution near the tip of a periodically corrugated metal cylinder-cone probe working at the terahertz regime was studied. We found that radially polarized terahertz radiation could be coupled effectively through a spoof SPP into a surface wave and propagated along the corrugated surface, resulting in more than 20× electric field enhancement near the tip of probe. Multiple resonances caused by the antenna effect were discussed in detail by finite element computation and theoretical analysis of dispersion relation for spoof SPP modes. Moreover, the key figures of merit such as the resonance frequency of the SPP can be flexibly tuned by modifying the geometry of the probe structure, making it attractive for application in an apertureless background-free terahertz near-field microscope. PMID:25121543

  13. CONTEXT VIEW, SHOWING STRUCTURE NO. 57.3X (CULVERT) AT RIGHT AND ...

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

    CONTEXT VIEW, SHOWING STRUCTURE NO. 57.3X (CULVERT) AT RIGHT AND STRUCTURE NO. 57.24X (BRIDGE) IN DISTANCE AT LEFT. MAIN TRACK 1 RUNS ALONG THE TOP OF THE FEATURES. VIEW TO THE SOUTHEAST. 12 - Burlington Northern Santa Fe Railroad, Cajon Subdivision, Structure No. 57.3X, Between Cajon Summit and Keenbrook, Devore, San Bernardino County, CA

  14. Imaging Buried Culverts Using Ground Penetrating Radar: Comparing 100 MHZ Through 1 GHZ Antennae

    NASA Astrophysics Data System (ADS)

    Abdul Aziz, A.; Stewart, R. R.; Green, S. L.

    2013-12-01

    *Aziz, A A aabdulaziz@uh.edu Allied Geophysical Lab, Department of Earth and Atmospheric Sciences, University of Houston, TX, USA Stewart, R R rrstewart@uh.edu Allied Geophysical Lab, Department of Earth and Atmospheric Sciences, University of Houston, TX, USA *Green, S L slgreen@yahoo.com Allied Geophysical Lab, Department of Earth and Atmospheric Sciences, University of Houston, TX, USA A 3D ground penetrating radar (GPR) survey, using three different frequency antennae, was undertaken to image buried steel culverts at the University of Houston's La Marque Geophysical Observatory 30 miles south of Houston, Texas. The four culverts, under study, support a road crossing one of the area's bayous. A 32 m by 4.5 m survey grid was designed on the road above the culverts and data were collected with 100 MHz, 250 MHz, and 1 GHz antennae. We used an orthogonal acquisition geometry for the three surveys. Inline sampling was from 1.0 cm to 10 cm (from 1 GHz to 100 MHz antenna) with inline and crossline spacings ranging from 0.2 m to 0.5 m. We used an initial velocity of 0.1 m/ns (from previous CMP work at the site) for the display purposes. The main objective of the study was to analyze the effect of different frequency antennae on the resultant GPR images. We are also interested in the accuracy and resolution of the various images, in addition to developing an optimal processing flow.The data were initially processed with standard steps that included gain enhancement, dewow and temporal-filtering, background suppression, and 2D migration. Various radar velocities were used in the 2D migration and ultimately 0.12 m/ns was used. The data are complicated by multipathing from the surface and between culverts (from modeling). Some of this is ameliorated via deconvolution. The top of each of the four culverts was evident in the GPR images acquired with the 250 MHz and 100 MHz antennas. For 1 GHz, the top of the culvert was not clear due to the signal's attenuation. The 250 MHz

  15. An Analysis of Stream Culvert Fish Passage on the Navy Railroad Line between Bremerton and Shelton, Washington

    SciTech Connect

    May, Christopher W.; Miller, Martin C.; Southard, John A.

    2004-10-25

    The Navy railroad service line runs between Shelton, Bremerton, and Silverdale, and is used by the Navy to transfer freight to its facilities. It is also used by commercial clients to ship service items and bulk cargo for municipalities along portions of the route. Culverts of various size and construction convey streams and stormwater runoff under the railroad line. These allow transfer of water and, in some cases allow for passage of juvenile and adult salmon into waters upstream of the culverts. As part of this project, 21 culverts along a 34-mile reach (Shelton to Bremerton) of this railroad were surveyed to evaluate their function and ability to allow salmon to utilize the streams. The culverts and attached watersheds were evaluated using criteria developed by the Washington Department of Fish and Wildlife to assign a Priority Index (PI) to barriers present on each fish-bearing stream. The PI is a relative numeric rating indicator, assigned using consistent criteria related to the degree of potential habitat gained by removing barriers and improving the function of the watershed. Of the 21 culverts evaluated, five were found to be complete fish-passage barriers and six were found to be partial barriers, primarily to juvenile salmon. Three of these culverts had PI ratings above 10 and five others had ratings between 7 and 10. Corrective action can be taken based on any PI rating, but the WDFW normally assigns lower priority to projects with PI scores lower than 15. Several of the stream and culverts had previously been evaluated for structural integrity and function and have been scheduled for repair. A narrative indicating the condition of the culvert has been prepared as well as a table indicating the PI scores and a summary of recommendations for action for each culvert.

  16. 2. Elkmont, deck view of corrugated arched bridge. Great ...

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

    2. Elkmont, deck view of corrugated arched bridge. - Great Smoky Mountains National Park Roads & Bridges, Elkmont Vehicle Bridge, Spanning Little River at Elkmont Campground, Gatlinburg, Sevier County, TN

  17. 3. Elkmont, underside detail of corrugated arched bridge. Great ...

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

    3. Elkmont, underside detail of corrugated arched bridge. - Great Smoky Mountains National Park Roads & Bridges, Elkmont Vehicle Bridge, Spanning Little River at Elkmont Campground, Gatlinburg, Sevier County, TN

  18. Performance of zigzag corrugated furrows in Bolivia

    NASA Astrophysics Data System (ADS)

    Roldán Cañas, J.; Chipana, R.; Moreno-Pérez, M. F.; Chipana, G.

    2012-04-01

    In Bolivia, irrigation area is estimated in more than 250000 ha, being surface irrigation the most common method. In highland areas (Altiplano) and in interandean valleys, traditional and ancestral irrigation systems such as flood irrigation, contour furrows, zigzag corrugated furrows, suka kollus and irrigation by kanis, are the most important. In the case of very steep terrains and shallow soils, the zigzag corrugated irrigation method is very frequent. This irrigation method has been used for a long time but their low application efficiency and the shortage of water justify this work devoted to their characterization and to study their performance. The experimental study was conducted southeast of the city of La Paz in the community of Cebollino located at 2600 meters above sea level. Furrow characteristics vary in function of crop type and soil slope, so that the larger the slope the greater the separation between furrows. In our case, the crop chosen was the lettuce and the experimental plot had an area of 800 m2 with a slope ranging between 14 and 18%. Blocks of corrugated furrows were identified and experimental measures were made during each irrigation, once per week, in the central blocks to avoid border effects. To determine advance curves 15 stations were used spaced 18 m. At each station, advance and recession time and infiltration depth were measured. Inlet and outlet flow were controlled each 5 min. To calculate the reference evapotranspiration, the Hargraves-Samani equation was used. Due to the very high terrain slopes, the advance curve takes a linear form rather than the typical exponential form. This hinders the proper calculation of the parameters of the Kostiakov-Lewis equation used to determine the infiltrated depth values. The inlet flow range, along irrigation events, between 0.01 and 0.085 L/s due to the uncontrolled use of water in fields located upstream. The large variability of inflow flow difficult irrigation management especially in

  19. Pipe support

    DOEpatents

    Pollono, Louis P.

    1979-01-01

    A pipe support for high temperature, thin-walled piping runs such as those used in nuclear systems. A section of the pipe to be supported is encircled by a tubular inner member comprised of two walls with an annular space therebetween. Compacted load-bearing thermal insulation is encapsulated within the annular space, and the inner member is clamped to the pipe by a constant clamping force split-ring clamp. The clamp may be connected to pipe hangers which provide desired support for the pipe.

  20. Multimode corrugated waveguide feed for monopulse radar

    NASA Astrophysics Data System (ADS)

    Clarricoats, P. J. B.; Elliot, R. D.

    1981-04-01

    The paper describes the behavior of a multimode corrugated feed for use in monopulse radar. Four square input waveguides are used to excite sum- and difference-channel modes. With appropriate choice of parameters it is possible to generate radiation patterns with low crosspolarization thus allowing the polarization characteristics of a target to be obtained. The results of an analysis of the relevant waveguide discontinuity problem are presented and a means to compensate phase differences between modes is also described. Some preliminary experimental results are found to be in accord with theory.

  1. [The corrugator supercilii muscle. A review].

    PubMed

    Bartolin, C; Lalo, J

    2008-12-01

    Corrugator supercilii is a facial, forehead and supra-orbital muscle. The frown glabellar wrinkles are mainly formed by repeated contractions of this muscle. These wrinkles will produce the picture of premature ageing even in a young person. Many treatments reduce or abolish the action of this muscle, enhancing the appearance of the glabellar area. We propose to review the recent material related to the anatomical characteristics of this muscle in order to build the necessary knowledge to optimize the result of these different treatments.

  2. Disappointment and regret enhance corrugator reactivity in a gambling task

    PubMed Central

    Wu, Yin; Clark, Luke

    2015-01-01

    This study investigated how the corrugator and zygomaticus respond to decision outcomes (i.e., gains and losses). We used a gambling task in which participants were presented with obtained followed by non-obtained outcomes. Activity at the corrugator site was sensitive to decision outcomes, such that higher obtained losses (disappointment) and higher non-obtained gains (regret) both heightened corrugator reactivity. Activity at the zygomaticus site was not responsive to obtained or non-obtained outcomes, but did show sensitivity to emotional images in the same participants, in the form of a positive linear relationship with self-reported emotional valence. Corrugator activity was negatively related to emotional valence. The findings indicate the sensitivity of corrugator to objective decision outcomes and also counterfactual comparisons, highlighting the utility of facial electromyography in research on decision making and gambling behavior. PMID:25345723

  3. Scalar Casimir-Polder forces for uniaxial corrugations

    SciTech Connect

    Doebrich, Babette; DeKieviet, Maarten; Gies, Holger

    2008-12-15

    We investigate the Dirichlet-scalar equivalent of Casimir-Polder forces between an atom and a surface with arbitrary uniaxial corrugations. The complexity of the problem can be reduced to a one-dimensional Green's function equation along the corrugation which can be solved numerically. Our technique is fully nonperturbative in the height profile of the corrugation. We present explicit results for experimentally relevant sinusoidal and sawtooth corrugations. Parameterizing the deviations from the planar limit in terms of an anomalous dimension which measures the power-law deviation from the planar case, we observe up to order-one anomalous dimensions at small and intermediate scales and a universal regime at larger distances. This large-distance universality can be understood from the fact that the relevant fluctuations average over corrugation structures smaller than the atom-wall distance.

  4. Pipe Dreams.

    ERIC Educational Resources Information Center

    Milshtein, Amy

    2002-01-01

    Discusses the importance of attention to plumbing in college facilities, offering examples from various campuses. Addresses preventive maintenance, technology, and piping materials, including the debate between cast iron and PVC for drain pipes. (EV)

  5. Corrugated Quantum Well Infrared Photodetectors and Arrays

    NASA Technical Reports Server (NTRS)

    Choi, K. K.; Chen, C. J.; Rohkinson, L. P.; Das, N. C.; Jhabvala, M.

    1999-01-01

    Quantum well infrared photodetectors (QWIPs) have many advantages in infrared detection, mainly due to the mature Ill-V material technology. The employment of the corrugation structure further advances the technology by providing a simple, yet efficient light-coupling scheme. A C-QWIP enjoys the same flexibility as a detector with intrinsic normal incident absorption. In this paper, we will discuss the utilities of C-QWIPs in different applications, including two-color detection and polarization-sensitive detection. Besides practical applications, C-QWIPs are also useful in detector characterization. They can be used for measuring the absorption coefficient of light propagating parallel to the layers under bias and providing information on the energy resolved photoconductive gain. These two quantities have never been measured before. Based on the corrugation design, we have made several modifications that further improve the detector sensitivity without increasing its complexity. Other than the C-QWIP structure, we also continue searching for other sensitive detector architectures. In a quantum grid infrared photodetector, 3-dimensional electron confinement can be achieved, with which the detector is able to absorb light in all directions. At the same time, the photoconductive gain can also be improved. We further improve the design using a blazed structure. All the experimental results are supported by a rigorous electromagnetic modal transmission-line theory developed especially for these types of structures. Preliminary thermal imaging using C-QWIP FPAs validates the advantages of the present approach.

  6. Corrugation Profile for the Quasioptical Polarization Separator

    NASA Astrophysics Data System (ADS)

    Koposova, E. V.; Lubyako, L. V.

    2014-07-01

    We consider and classify the regime of separation of two orthogonally polarized E and H waves by using a reflecting metal diffraction grating, which sends all the energy of an incident wave with one polarization to the specular order of diffraction, and that of an incident wave with the other polarization, to the (-1)st order of diffraction (in this case, the autocollimation regime is used). The conditions of existence of such a regime are studied in the simplest cases (generalization of the approach presented in [1, 2] to the case of a sinusoidal surface), along with the possibility to construct more complex (nonsinusoidal) corrugation profiles, for which the specified regime has certain advantages, e.g., a wider bandwidth. Examples of such profiles are presented. The studies are performed on the basis of numerical solution of the problem of diffraction of a plane electromagnetic wave by a perfectly conducting corrugated surface within the framework of the integral-equation method employing the authors' computer visualization code.

  7. Biased Brownian motion in extremely corrugated tubes

    NASA Astrophysics Data System (ADS)

    Martens, S.; Schmid, G.; Schimansky-Geier, L.; Hänggi, P.

    2011-12-01

    Biased Brownian motion of point-size particles in a three-dimensional tube with varying cross-section is investigated. In the fashion of our recent work, Martens et al. [Phys. Rev. E 83, 051135 (2011)] we employ an asymptotic analysis to the stationary probability density in a geometric parameter of the tube geometry. We demonstrate that the leading order term is equivalent to the Fick-Jacobs approximation. Expression for the higher order corrections to the probability density is derived. Using this expansion orders, we obtain that in the diffusion dominated regime the average particle current equals the zeroth order Fick-Jacobs result corrected by a factor including the corrugation of the tube geometry. In particular, we demonstrate that this estimate is more accurate for extremely corrugated geometries compared with the common applied method using a spatially-dependent diffusion coefficient D(x, f) which substitutes the constant diffusion coefficient in the common Fick-Jacobs equation. The analytic findings are corroborated with the finite element calculation of a sinusoidal-shaped tube.

  8. Open top culverts as an alternative drainage system to minimize ecological effects in earth roads.

    NASA Astrophysics Data System (ADS)

    García, Jose L.; Elorrieta, Jose; Robredo, Jose C.; García, Ricardo; García, Fernando; Gimenez, Martin C.

    2013-04-01

    During the last fifteen years a research team from School of Forestry at the Technical University of Madrid (Spain) has developed several competitive research projects regarding forest roads and open top culverts. A first approach was established with a prototype of 7 meters length in a hydraulic channel at the laboratory determining main parameters of different open top culverts in relation to different sizes of gravels and the self washing properties relationship with different slopes up to 8 %. The curves obtained may help to properly install these drainage systems avoiding maintenance costs. In addition more targeted pilot studies were developed in different forest earth roads in center and north Spain. The construction of the stations under study was financed by the U.P.M and the R&D National Plan. The main outcomes relates the low variation of humidity in a 20 m. wide range at both sides of the open top culverts and several considerations relating the angle of installation, the spacing of such drainage systems and the benefits against rilling along the roads. Also the erosion produced downhill was established and some construction methods to avoid adverse ecological effects. The diffusion of results includes congresses and a small booklet with a great acceptance in forestry services. Also a patent (ES 2 262 437) of an advanced model has been registered.

  9. Supplement Analysis for the Watershed Management Program EIS (DOE/EIS-0265/SA-91) - Hood River Fish Habitat (Evans Creek Culvert Replacement)

    SciTech Connect

    Yarde, Richard

    2002-10-01

    BPA and the Confederated Tribes of the Warm Springs Reservation of Oregon (CTWSRO) propose to remove a culvert acting as a fish passage barrier, and replace it with a bridge. The culvert is located on a private residential / farm access road on Evans Creek, a tributary to the East Fork Hood River. The culvert will be replaced with a clear-span bridge in order to eliminate the passage barrier and open several miles of stream as fish habitat.

  10. The effects of road crossings on prairie stream habitat and function

    USGS Publications Warehouse

    Bouska, Wesley W.; Keane, Timothy; Paukert, Craig P.

    2010-01-01

    Improperly designed stream crossing structures may alter the form and function of stream ecosystems and habitat and prohibit the movement of aquatic organisms. Stream sections adjoining five concrete box culverts, five low-water crossings (concrete slabs vented by one or multiple culverts), and two large, single corrugated culvert vehicle crossings in eastern Kansas streams were compared to reference reaches using a geomorphologic survey and stream classification. Stream reaches were also compared upstream and downstream of crossings, and crossing measurements were used to determine which crossing design best mimicked the natural dimensions of the adjoining stream. Four of five low-water crossings, three of five box culverts, and one of two large, single corrugated pipe culverts changed classification from upstream to downstream of the crossings. Mean riffle spacing upstream at low-water crossings (8.6 bankfull widths) was double that of downstream reaches (mean 4.4 bankfull widths) but was similar upstream and downstream of box and corrugated pipe culverts. There also appeared to be greater deposition of fine sediments directly upstream of these designs. Box and corrugated culverts were more similar to natural streams than low-water crossings at transporting water, sediments, and debris during bankfull flows.

  11. Composite corrugated structures for morphing wing skin applications

    NASA Astrophysics Data System (ADS)

    Thill, C.; Etches, J. A.; Bond, I. P.; Potter, K. D.; Weaver, P. M.

    2010-12-01

    Composite corrugated structures are known for their anisotropic properties. They exhibit relatively high stiffness parallel (longitudinal) to the corrugation direction and are relatively compliant in the direction perpendicular (transverse) to the corrugation. Thus, they offer a potential solution for morphing skin panels (MSPs) in the trailing edge region of a wing as a morphing control surface. In this paper, an overview of the work carried out by the present authors over the last few years on corrugated structures for morphing skin applications is first given. The second part of the paper presents recent work on the application of corrugated sandwich structures. Panels made from multiple unit cells of corrugated sandwich structures are used as MSPs in the trailing edge region of a scaled morphing aerofoil section. The aerofoil section features an internal actuation mechanism that allows chordwise length and camber change of the trailing edge region (aft 35% chord). Wind tunnel testing was carried out to demonstrate the MSP concept but also to explore its limitations. Suggestions for improvements arising from this study were deduced, one of which includes an investigation of a segmented skin. The overall results of this study show that the MSP concept exploiting corrugated sandwich structures offers a potential solution for local morphing wing skins for low speed and small air vehicles.

  12. Iron line variability of discoseismic corrugation modes

    NASA Astrophysics Data System (ADS)

    Tsang, David; Butsky, Iryna

    2013-10-01

    Using a fast semi-analytic raytracing code, we study the variability of relativistically broadened Fe-Kα lines due to discoseismic oscillations concentrated in the innermost regions of accretion discs around black holes. The corrugation mode, or c-mode, is of particular interest as its natural frequency corresponds well to the ˜0.1-15 Hz range observed for low-frequency quasi-periodic oscillations (LFQPOs) for lower spins. Comparison of the oscillation phase dependent variability and quasi-periodic oscillation-phase stacked Fe-Kα line observations will allow such discoseismic models to be confirmed or ruled out as a source of particular LFQPOs. The spectral range and frequency of the variability of the Fe-Kα line due to c-modes can also potentially be used to constrain the black hole spin if observed with sufficient temporal and spectral resolution.

  13. Fatigue testing of corrugated and Teflon hoses

    NASA Technical Reports Server (NTRS)

    Benner, Steve M.; Swanson, Theodore D.; Costello, Frederick A.

    1990-01-01

    Single and two-phase heat transport systems for the thermal control of large space facilities require fluid lines that traverse joints and either rotate or move in some other manner. Flexible hoses are being considered as one means of traversing these joints. To test the resilience of flexible hoses to bending stress, a test assembly was constructed to determine the number of flexing cycles the hoses could withstand before losing their ability to maintain a constant pressure. Corrugated metal hoses and Teflon hoses were tested at different pressures with nitrogen gas. The metal hoses had lives ranging from 30,000 to 100,000 flexing cycles. But, even after 400,000 cycles, the Teflon hoses remained essentially intact, though some leakage in the convoluted Teflon is noted.

  14. Effective Thermal Conductivity of Corrugated Insulating Materials

    NASA Astrophysics Data System (ADS)

    Yamada, Etsuro; Kato, Masayasu; Tomikawa, Takayuki; Takahashi, Kaneko

    The effective thermal conductivity of corrugated insulating materials which are made by polypropylene or polycarbonate have been measured by employing steady state comparison method for several specimen having various thickness and specific weight. The thermal conductivity of them evaluated are also by using the thermal resistance models, and are compared with above measured values and raw materials' conductivity. The main results obtained in this paper are as follows: (1) In regard to the specimen in this paper, the effective thermal conductivity increases with increasing temperature, but the increasing rate of them is small. (2) There are considerable differences between the measured values and the predicted ones that are estimated by using the thermal resistance model in which heat flow by conduction only. This differences increase with increasing specimens' thickness. This difference become extinct by considering the coexistence heat flow of conduction and radiation in the air phase of specimen. (3) The thermal resistance of specimen increases linearly with increasing specimens' thickness.

  15. Laser-Driven Corrugation Instability of Liquid Metal Surfaces

    NASA Astrophysics Data System (ADS)

    Keilmann, Fritz

    1983-12-01

    During intense CO2-laser irradiation deep corrugations build up on liquid metals such as Hg, In, Sn, Al, and Pb. Spacing, orientation, growth, and decay of the corrugations are studied, by visible light diffraction; support is found for a model of stimulated scattering where the incident light parametrically decays into both the surface corrugation and a surface plasmon. Thermal evaporation supplies the nonlinearity. The instability provides polarization-dependent absorption and can be expected in laser-metalworking and laser-plasma situations.

  16. Propagation and radiation characteristics of a multimode corrugated waveguide feedhorn

    NASA Technical Reports Server (NTRS)

    Hoppe, D.

    1985-01-01

    A prototype of the multimode corrugated feedhorn which will be used in the 400 kW CW Ka-band radar system is described. A rough design is done using coupled mode theory and standard corrugated waveguide modes. A more exact analysis using mode matching techniques is then used which takes into account the effect of a finite number of corrugations per wavelength and determines the modes which are reflected from the device. A prototype feedhorn has been constructed and measured. These experimental results are then compared to the theoretical predictions which agree satisfactorily closely.

  17. Propagation and radiation characteristics of a multimode corrugated waveguide feedhorn

    NASA Astrophysics Data System (ADS)

    Hoppe, D.

    1985-08-01

    A prototype of the multimode corrugated feedhorn which will be used in the 400 kW CW Ka-band radar system is described. A rough design is done using coupled mode theory and standard corrugated waveguide modes. A more exact analysis using mode matching techniques is then used which takes into account the effect of a finite number of corrugations per wavelength and determines the modes which are reflected from the device. A prototype feedhorn has been constructed and measured. These experimental results are then compared to the theoretical predictions which agree satisfactorily closely.

  18. Diverse corrugation pattern in radially shrinking carbon nanotubes

    SciTech Connect

    Shima, Hiroyuki; Sato, Motohiro; Iiboshi, Kohtaroh; Ghosh, Susanta; Arroyo, Marino

    2010-08-15

    Stable cross sections of multiwalled carbon nanotubes subjected to electron-beam irradiation are investigated in the realm of the continuum mechanics approximation. The self-healing nature of sp{sup 2} graphitic sheets implies that selective irradiation of the outermost walls causes their radial shrinkage with the remaining inner walls undamaged. The shrinking walls exert high pressure on the interior part of nanotubes, yielding a wide variety of radial-corrugation patterns (i.e., circumferentially wrinkling structures) in the cross section. All corrugation patterns can be classified into two deformation phases for which the corrugation amplitudes of the innermost wall differ significantly.

  19. A comparative study of corrugated horn design by evolutionary techniques

    NASA Technical Reports Server (NTRS)

    Hoorfar, A.

    2003-01-01

    Here an evolutionary programming algorithm is used to optimize the pattern of a corrugated circular horn subject to various constraints on return loss, antenna beamwidth, pattern circularity, and low cross polarization.

  20. 7. DETAIL VIEW UNDER BRIDGE OF CORRUGATED STEEL, BEAMS, RODS, ...

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

    7. DETAIL VIEW UNDER BRIDGE OF CORRUGATED STEEL, BEAMS, RODS, AND ABUTMENT - Price River Bridge, Spanning Price River, 760 North Street in Carbonville, 1 mile northwest of Price, Carbonville, Carbon County, UT

  1. Hydrodynamics of Gas-Liquid Counterflow Through Corrugated Parallel Plates

    SciTech Connect

    de Almeida, V.F.

    1999-11-05

    Structured packings utilized in today's distillation packed towers consist of stacked units of many vertically oriented parallel corrugated plates. The V-shaped corrugations are oriented at a fixed angle with respect to the vertical direction, and the corrugation angle in adjacent plates are oriented in reverse direction. Points of contact, at the crests of the corrugations, between adjacent plates, form an unconsolidated porous medium with known topology. Modern structured packings have been gaining acceptance in several separation processes, particularly distillation where gas/vapor and liquid flow countercurrently through the packing. In addition, structured packings have been credited with relatively low pressure drop, high efficiency, low holdup, and higher capacity; the packing also can be made corrosion resistive.

  2. 1. Elkmont vehicle bridge at Elkmont Campground, galvanized corrugated arch. ...

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

    1. Elkmont vehicle bridge at Elkmont Campground, galvanized corrugated arch. - Great Smoky Mountains National Park Roads & Bridges, Elkmont Vehicle Bridge, Spanning Little River at Elkmont Campground, Gatlinburg, Sevier County, TN

  3. Heat Pipes

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Phoenix Refrigeration Systems, Inc.'s heat pipe addition to the Phoenix 2000, a supermarket rooftop refrigeration/air conditioning system, resulted from the company's participation in a field test of heat pipes. Originally developed by NASA to control temperatures in space electronic systems, the heat pipe is a simple, effective, heat transfer system. It has been used successfully in candy storage facilities where it has provided significant energy savings. Additional data is expected to fully quantify the impact of the heat pipes on supermarket air conditioning systems.

  4. Bandwidth Study of the Microwave Reflectors with Rectangular Corrugations

    NASA Astrophysics Data System (ADS)

    Zhang, Liang; He, Wenlong; Donaldson, Craig R.; Cross, Adrian W.

    2016-09-01

    The mode-selective microwave reflector with periodic rectangular corrugations in the inner surface of a circular metallic waveguide is studied in this paper. The relations between the bandwidth and reflection coefficient for different numbers of corrugation sections were studied through a global optimization method. Two types of reflectors were investigated. One does not consider the phase response and the other does. Both types of broadband reflectors operating at W-band were machined and measured to verify the numerical simulations.

  5. Pipe connector

    DOEpatents

    Sullivan, Thomas E.; Pardini, John A.

    1978-01-01

    A safety test facility for testing sodium-cooled nuclear reactor components includes a reactor vessel and a heat exchanger submerged in sodium in the tank. The reactor vessel and heat exchanger are connected by an expansion/deflection pipe coupling comprising a pair of coaxially and slidably engaged tubular elements having radially enlarged opposed end portions of which at least a part is of spherical contour adapted to engage conical sockets in the ends of pipes leading out of the reactor vessel and in to the heat exchanger. A spring surrounding the pipe coupling urges the end portions apart and into engagement with the spherical sockets. Since the pipe coupling is submerged in liquid a limited amount of leakage of sodium from the pipe can be tolerated.

  6. Do Steel Bridges Prevent Rail Corrugations?

    NASA Astrophysics Data System (ADS)

    Meinke, Peter; Stephanides, Johannes

    2010-03-01

    Rail corrugations (germ. "Schlupfwellen") are wear pattern, which emerge during the transits of railway vehicles at narrow railway curves (R ≤ 250 m) and they are a menace to railway operators, especially if their railroad network exists in mountains. Therefore ÖBB started recently a research program "OBO" (Optimierter Bogenoberbau) for better understanding and avoidance of "Schlupfwellen", which is mainly experimentally oriented. As a representative test track was the extended famous narrow curve at the valley of Brixen close to Kitzbühl chosen, and two Measurement sites where there established, one embedded in the ballasted track bed and another one on a steel bridge, situated in this curve. Measuring the passing trains, a rearly astonishing fact was discovered: Whereas in the ballasted track all well known typical features occur (vibration, bending and torsion of the rail,…), which produce the wear created Schlupfwellen and the dedicated grumbling noise, the wheelsets run properly on the steel bridge track and pass "friendly" the associated curve segment! Dicussing the ascertained fact, it was realized that on many European steel bridges such phenomena happens! The paper ends assuming that a broad-band vibration of the rail heads upon the steel bridge reduces the friction coefficient in the wheel/rail contact area ("Flange oilers"). This can be the reason for the smooth travel at the bridge. This may also be the basis for a technical application to overcome the generation of Schlupfwellen?

  7. Silo with a Corrugated Sheet Wall

    NASA Astrophysics Data System (ADS)

    Németh, Csaba; Brodniansky, Ján

    2013-09-01

    Silos and tanks are currently being used to create reserves of stored materials. Their importance is based on balancing the production and consumption of bulk materials to establish an adequate reserve throughout the year. The case study introduced within the framework of this paper focuses on thin-walled silos made of corrugated sheets and on an approach for designing these types of structures. The storage of bulk materials causes compression or tensile stresses in the walls of a silo structure. The effect of a frictional force in the silo walls creates an additional bending moment in a wave, which ultimately affects the resulting bending moments. Several mathematical and physical models were used in order to examine various types of loading and their effects on a structure. Subsequently, the accuracy of the computational models was verified by experimental measurements on a grain silo in Bojničky, Slovakia. A comparison of the experimental and mathematical models shows a reasonable match and confirms the load specifications, while indicating that the mathematical model was correct.

  8. Directional and enhanced spontaneous emission with a corrugated metal probe

    NASA Astrophysics Data System (ADS)

    Shen, Hongming; Lu, Guowei; He, Yingbo; Cheng, Yuqing; Liu, Haitao; Gong, Qihuang

    2014-06-01

    A three-dimensional corrugated metal tapered probe with surface corrugated gratings at the tip apex is proposed and investigated theoretically, which leads to an obvious emission beaming effect of spontaneous emission from a single emitter near the probe. In contrast with conventional apertureless metal probes, where only the enhancement of an optical near-field is concerned, the corrugated probe is able to manipulate local excitation intensity and far-field emission direction simultaneously. The angular emission from a single dipole source, being placed close to the corrugated probe, falls into a cone with a maximum directivity angle of +/-11.6°, which improves the collection efficiency 25-fold. Such a probe simultaneously increases the localized field intensity to about twice as strong as the conventional bare tip. In addition, the radiation pattern is sensitive to the working wavelength and the dipole to tip-apex separation. These findings make a promising route to the development of plasmonic spontaneous emission manipulation based on corrugated tapered antenna--for instance, tip-enhanced spectroscopy, single-molecule sensing, and single-photon source .

  9. Detection of rail corrugation based on fiber laser accelerometers

    NASA Astrophysics Data System (ADS)

    Huang, Wenzhu; Zhang, Wentao; Du, Yanliang; Sun, Baochen; Ma, Huaixiang; Li, Fang

    2013-09-01

    Efficient inspection methods are necessary for detection of rail corrugation to improve the safety and ride quality of railway operations. This paper presents a novel fiber optic technology for detection of rail corrugation based on fiber laser accelerometers (FLAs), tailored to the measurement of surface damage on rail structures. The principle of detection of rail corrugation using double integration of axle-box acceleration is presented. Then we present the theoretical model and test results of FLAs which are installed on the bogie to detect the vertical axle-box acceleration of the train. Characteristics of high sensitivity and large dynamic range are achieved when using fiber optic interferometric demodulation. A flexible inertial algorithm based on double integration and the wavelet denoising method is proposed to accurately estimate the rail corrugation. A field test is carried out on the Datong-Qinhuangdao Railway in north China. The test results are compared with the results of a rail inspection car, which shows that the fiber laser sensing system has a good performance in monitoring rail corrugation.

  10. 49 CFR 1242.15 - Roadway, tunnels and subways, bridges and culverts, ties, rails, other track material, ballast...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 9 2010-10-01 2010-10-01 false Roadway, tunnels and subways, bridges and culverts, ties, rails, other track material, ballast, track laying and surfacing, and road property damaged... RAILROADS 1 Operating Expenses-Way and Structures § 1242.15 Roadway, tunnels and subways, bridges...

  11. Corrugated horn of HE/11/ and HE/21/ mode

    NASA Astrophysics Data System (ADS)

    Yang, S.-H.; Ke, S.-R.; Peng, G.-Z.

    A corrugated, monopulse feed conical horn is described which uses HE(11) as the sum mode and HE(21) as the difference mode. It is shown that when the horn aperture radius-to-free space wavelength ratio is large, the balanced hybrid condition can be met for both modes in order to yield rotational symmetry beams and low sidelobe levels. A discussion is given of the mode selection method which uses special points on trace charts, and that which uses a ringloaded, corrugated taper section as the transformation section from the smooth-wall waveguide to the corrugated horn. The input voltage standing wave ratio measured in the sum channel is less than 1.05 in 20% bandwidth.

  12. Corrugated capillary as THz Cherenkov Smith-Purcell radiator

    NASA Astrophysics Data System (ADS)

    Lekomtsev, K. V.; Aryshev, A. S.; Tishchenko, A. A.; Ponomarenko, A. A.; Sukharev, V. M.; Terunuma, N.; Urakawa, J.; Strikhanov, M. N.

    2016-07-01

    In this article we discussed Particle In Cell electromagnetic simulations and mechanical design of dielectric capillaries that produce THz Cherenkov Smith-Purcell radiation (ChSPR), arising when a femtosecond electron multi-bunch beam propagates through corrugated and non-corrugated dielectric capillaries with metallic radiation reflectors. We investigated the influence of the four-bunch beam on the SPR field spectrum and on the ChSPR power spectrum, and the influence of the non-central beam propagation on the ChSPR power spectrum. We also discussed the design and assembly of the capillaries, constructed as sets of cylindrical rings.

  13. Heat Pipes

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Bobs Candies, Inc. produces some 24 million pounds of candy a year, much of it 'Christmas candy.' To meet Christmas demand, it must produce year-round. Thousands of cases of candy must be stored a good part of the year in two huge warehouses. The candy is very sensitive to temperature. The warehouses must be maintained at temperatures of 78-80 degrees Fahrenheit with relative humidities of 38- 42 percent. Such precise climate control of enormous buildings can be very expensive. In 1985, energy costs for the single warehouse ran to more than $57,000 for the year. NASA and the Florida Solar Energy Center (FSEC) were adapting heat pipe technology to control humidity in building environments. The heat pipes handle the jobs of precooling and reheating without using energy. The company contacted a FSEC systems engineer and from that contact eventually emerged a cooperative test project to install a heat pipe system at Bobs' warehouses, operate it for a period of time to determine accurately the cost benefits, and gather data applicable to development of future heat pipe systems. Installation was completed in mid-1987 and data collection is still in progress. In 1989, total energy cost for two warehouses, with the heat pipes complementing the air conditioning system was $28,706, and that figures out to a cost reduction.

  14. Piping Connector

    NASA Technical Reports Server (NTRS)

    1993-01-01

    A complex of high pressure piping at Stennis Space Center carries rocket propellants and other fluids/gases through the Center's Component Test Facility. Conventional clamped connectors tend to leak when propellant lines are chilled to extremely low temperatures. Reflange, Inc. customized an existing piping connector to include a secondary seal more tolerant of severe thermal gradients for Stennis. The T-Con connector solved the problem, and the company is now marketing a commercial version that permits testing, monitoring or collecting any emissions that may escape the primary seal during severe thermal transition.

  15. Pipe gripper

    DOEpatents

    Moyers, S.M.

    1975-12-16

    A device for gripping the exterior surface of a pipe or rod is described which has a plurality of wedges, each having a concave face which engages the outer surface of the pipe and each having a smooth face opposing the concave face. The wedges are seated on and their grooved concave faces are maintained in circular alignment by tapered axial segments of an opening extending through a wedge-seating member. The wedges are allowed to slide across the tapered axial segments so that such a sliding movement acts to vary the diameter of the circular alignment.

  16. Heat Pipes

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Heat Pipes were originally developed by NASA and the Los Alamos Scientific Laboratory during the 1960s to dissipate excessive heat build- up in critical areas of spacecraft and maintain even temperatures of satellites. Heat pipes are tubular devices where a working fluid alternately evaporates and condenses, transferring heat from one region of the tube to another. KONA Corporation refined and applied the same technology to solve complex heating requirements of hot runner systems in injection molds. KONA Hot Runner Systems are used throughout the plastics industry for products ranging in size from tiny medical devices to large single cavity automobile bumpers and instrument panels.

  17. A corrugated termination shock in pulsar wind nebulae?

    NASA Astrophysics Data System (ADS)

    Lemoine, Martin

    2016-08-01

    > Successful phenomenological models of pulsar wind nebulae assume efficient dissipation of the Poynting flux of the magnetized electron-positron wind as well as efficient acceleration of the pairs in the vicinity of the termination shock, but how this is realized is not yet well understood. This paper suggests that the corrugation of the termination shock, at the onset of nonlinearity, may lead towards the desired phenomenology. Nonlinear corrugation of the termination shock would convert a fraction of order unity of the incoming ordered magnetic field into downstream turbulence, slowing down the flow to sub-relativistic velocities. The dissipation of turbulence would further preheat the pair population on short length scales, close to equipartition with the magnetic field, thereby reducing the initial high magnetization to values of order unity. Furthermore, it is speculated that the turbulence generated by the corrugation pattern may sustain a relativistic Fermi process, accelerating particles close to the radiation reaction limit, as observed in the Crab nebula. The required corrugation could be induced by the fast magnetosonic modes of downstream nebular turbulence; but it could also be produced by upstream turbulence, either carried by the wind or seeded in the precursor by the accelerated particles themselves.

  18. Bending of five-layer beams with crosswise corrugated main core

    SciTech Connect

    Magnucka-Blandzi, Ewa; Walczak, Zbigniew

    2015-03-10

    The subject of the study is one orthotropic thin-walled sandwich beam with trapezoidal core and two-layer facings. The outer layers of facings are flat, but inner layers are trapezoidal corrugated. The main core of the beam is also trapezoidal corrugated – in perpendicular direction to the corrugation of inner layers of facings. The beam is with lengthwise corrugated layers and crosswise corrugated main core. The mathematical and physical model of this beam is formulated, and also the field of displacements. The system of equilibrium equations is analytically derived using the energy method. The obtained solutions will be verified numerically (FEM)

  19. Stormwater chemical contamination caused by cured-in-place pipe (CIPP) infrastructure rehabilitation activities.

    PubMed

    Tabor, Matthew L; Newman, Derrick; Whelton, Andrew J

    2014-09-16

    Cured-in-place pipe (CIPP) is becoming a popular U.S. stormwater culvert rehabilitation method. Several State transportation agencies have reported that CIPP activities can release styrene into stormwater, but no other contaminants have been monitored. CIPP's stormwater contamination potential and that of its condensate waste was characterized. Condensate completely dissolved Daphnia magna within 24 h. Condensate pH was 6.2 and its chemical oxygen demand (COD) level was 36,000 ppm. D. magna mortality (100%) occurred in 48 h, even when condensate was diluted by a factor of 10,000 and styrene was present at a magnitude less than its LC50. Condensate and stormwater contained numerous carcinogenic solvents used in resin synthesis, endocrine disrupting contaminants such as plasticizers, and initiator degradation products. For 35 days, COD levels at the culvert outlets and downstream ranged from 100 to 375 ppm and styrene was 0.01 to 7.4 ppm. Although contaminant levels generally reduced with time, styrene levels were greatest 50 ft downstream, not at the culvert outlet. Cured CIPP extraction tests confirmed that numerous contaminants other than styrene were released into the environment and their persistence and toxicity should be investigated. More effective contaminant containment and cleaner installation processes must be developed to protect the environment.

  20. Condensation of refrigerants flowing inside smooth and corrugated tubes

    SciTech Connect

    Hinton, D.L.; Conklin, J.C.; Vineyard, E.A.

    1995-07-01

    Because heat exchanger thermal performance has a direct fluence on the overall cycle performance of vapor-compression refrigeration machinery,enhanced heat transfer surfaces are of interest to improve the efficiency of heat pumps and air conditioners. We investigated R-22 and a nonazeotropic refrigerant mixture (NARM) of 75% R-143a and 25% R-124 (by mass) to study their thermal performance in a condenser made of conventional smooth tubes and another condenser made of corrugated, or spirally indented, tubes. We investigated the condensing heat transfer and pressure drop characteristics in an experimental test loop model of a domestic beat pump system employing a variable speed compressor. The refrigerant circulates inside the central tube and the water circulates in the annulus. At refrigerant mass fluxes of approximately 275--300 kg/m{sup 2}s, the measured irreversible pressure drop of the corrugated surface was 23% higher than that of the smooth surface for the R-22. At refrigerant mass fluxes of 350-370 kg/m{sup 2}s, the irreversible pressure drop of the corrugated surface was 36% higher than that of the smooth surface for the NARM. The average heat transfer coefficient for the corrugated surface for R-22 was roughly 40% higher than that for the smooth tube surface at refrigerant mass fluxes of 275--295 kg/m{sup 2}s. The average heat transfer coefficient for the corrugated surface for the NARM was typically 70% higher than that for the smooth tube surface at refrigerant mass fluxes of 340--385 kg/m{sup 2}s.

  1. Test of superplastically formed corrugated aluminum compression specimens with beaded webs

    NASA Technical Reports Server (NTRS)

    Davis, Randall C.; Royster, Dick M.; Bales, Thomas T.; James, William F.; Shinn, Joseph M., Jr.

    1991-01-01

    Corrugated wall sections provide a highly efficient structure for carrying compressive loads in aircraft and spacecraft fuselages. The superplastic forming (SPF) process offers a means to produce complex shells and panels with corrugated wall shapes. A study was made to investigate the feasibility of superplastically forming 7475-T6 aluminum sheet into a corrugated wall configuration and to demonstrate the structural integrity of the construction by testing. The corrugated configuration selected has beaded web segments separating curved-cap segments. Eight test specimens were fabricated. Two specimens were simply a single sheet of aluminum superplastically formed to a beaded-web, curved-cap corrugation configuration. Six specimens were single-sheet corrugations modified by adhesive bonding additional sheet material to selectively reinforce the curved-cap portion of the corrugation. The specimens were tested to failure by crippling in end compression at room temperature.

  2. Aerodynamic effects of corrugation and deformation in flapping wings of hovering hoverflies.

    PubMed

    Du, Gang; Sun, Mao

    2012-05-01

    We investigated the aerodynamic effects of wing deformation and corrugation of a three-dimensional model hoverfly wing at a hovering condition by solving the Navier-Stokes equations on a dynamically deforming grid. Various corrugated wing models were tested. Insight into whether or not there existed significant aerodynamic coupling between wing deformation (camber and twist) and wing corrugation was obtained by comparing aerodynamic forces of four cases: a smooth-plate wing in flapping motion without deformation (i.e. a rigid flat-plate wing in flapping motion); a smooth-plate wing in flapping motion with deformation; a corrugated wing in flapping motion without deformation (i.e. a rigid corrugated wing in flapping motion); a corrugated wing in flapping motion with deformation. There was little aerodynamic coupling between wing deformation and corrugation: the aerodynamic effect of wing deformation and corrugation acting together was approximately a superposition of those of deformation and corrugation acting separately. When acting alone, the effect of wing deformation was to increase the lift by 9.7% and decrease the torque (or aerodynamic power) by 5.2%, and that of wing corrugation was to decrease the lift by 6.5% and increase the torque by 2.2%. But when acting together, the wing deformation and corrugation only increased the lift by ~3% and decreased the torque by ~3%. That is, the combined aerodynamic effect of deformation and corrugation is rather small. Thus, wing corrugation is mainly for structural, not aerodynamic, purpose, and in computing or measuring the aerodynamic forces, using a rigid flat-plate wing to model the corrugated deforming wing at hovering condition can be a good approximation. PMID:22266123

  3. Aerodynamic effects of corrugation and deformation in flapping wings of hovering hoverflies.

    PubMed

    Du, Gang; Sun, Mao

    2012-05-01

    We investigated the aerodynamic effects of wing deformation and corrugation of a three-dimensional model hoverfly wing at a hovering condition by solving the Navier-Stokes equations on a dynamically deforming grid. Various corrugated wing models were tested. Insight into whether or not there existed significant aerodynamic coupling between wing deformation (camber and twist) and wing corrugation was obtained by comparing aerodynamic forces of four cases: a smooth-plate wing in flapping motion without deformation (i.e. a rigid flat-plate wing in flapping motion); a smooth-plate wing in flapping motion with deformation; a corrugated wing in flapping motion without deformation (i.e. a rigid corrugated wing in flapping motion); a corrugated wing in flapping motion with deformation. There was little aerodynamic coupling between wing deformation and corrugation: the aerodynamic effect of wing deformation and corrugation acting together was approximately a superposition of those of deformation and corrugation acting separately. When acting alone, the effect of wing deformation was to increase the lift by 9.7% and decrease the torque (or aerodynamic power) by 5.2%, and that of wing corrugation was to decrease the lift by 6.5% and increase the torque by 2.2%. But when acting together, the wing deformation and corrugation only increased the lift by ~3% and decreased the torque by ~3%. That is, the combined aerodynamic effect of deformation and corrugation is rather small. Thus, wing corrugation is mainly for structural, not aerodynamic, purpose, and in computing or measuring the aerodynamic forces, using a rigid flat-plate wing to model the corrugated deforming wing at hovering condition can be a good approximation.

  4. Buried pipe design

    SciTech Connect

    Mosler, A.P.

    1990-01-01

    This book covers basic information on proper, cost-effective design of buried-pipe systems for underground fluid transportation. Examines various pipe products available. Discusses soil engineering and piping mechanics. Specific topics include pipe-wall stresses and strains; design bases; rigid- and flexible-pipe analysis; soil pressure; and longitudinal, wheel, expansive-soil, and frost loading.

  5. Direct Acceleration of Electrons in a Corrugated Plasma Channel

    SciTech Connect

    Palastro, J. P.; Antonsen, T. M.; Morshed, S.; York, A. G.; Layer, B.; Aubuchon, M.; Milchberg, H. M.; Froula, D. H.

    2009-01-22

    Direct laser acceleration of electrons provides a low power tabletop alternative to laser wakefield accelerators. Until recently, however, direct acceleration has been limited by diffraction, phase matching, and material damage thresholds. The development of the corrugated plasma channel [B. Layer et al., Phys. Rev. Lett. 99, 035001 (2007)] has removed all of these limitations and promises to allow direct acceleration of electrons over many centimeters at high gradients using femtosecond lasers [A. G. York et al., Phys Rev. Lett 100, 195001 (2008), J. P. Palastro et al., Phys. Rev. E 77, 036405 (2008)]. We present a simple analytic model of laser propagation in a corrugated plasma channel and examine the laser-electron beam interaction. Simulations show accelerating gradients of several hundred MeV/cm for laser powers much lower than required by standard laser wakefield schemes. In addition, the laser provides a transverse force that confines the high energy electrons on axis, while expelling low energy electrons.

  6. Progress Toward Corrugated Feed Horn Arrays in Silicon

    SciTech Connect

    Britton, J.; Yoon, K. W.; Beall, J. A.; Becker, D.; Cho, H. M.; Hilton, G. C.; Niemack, M. D.; Irwin, K. D.

    2009-12-16

    We are developing monolithic arrays of corrugated feed horns fabricated in silicon for dual-polarization single-mode operation at 90, 145 and 220 GHz. The arrays consist of hundreds of platelet feed horns assembled from gold-coated stacks of micro-machined silicon wafers. As a first step, Au-coated Si waveguides with a circular, corrugated cross section were fabricated; their attenuation was measured to be less than 0.15 dB/cm from 80 to 110 GHz at room temperature. To ease the manufacture of horn arrays, electrolytic deposition of Au on degenerate Si without a metal seed layer was demonstrated. An apparatus for measuring the radiation pattern, optical efficiency, and spectral band-pass of prototype horns is described. Feed horn arrays made of silicon may find use in measurements of the polarization anisotropy of the cosmic microwave background radiation.

  7. Optimization of the leading edge segment of a corrugated wing

    NASA Astrophysics Data System (ADS)

    Khurana, Manas; Chahl, Javaan

    2014-03-01

    Insect wings consist of flat plates of membranes stiffened by spars. The effect of this structure is that the wings appear as corrugated surfaces when considered on chordwise sections. We know that aerodynamically efficient insects such as a dragonfly engage in fixed wing flight modes for extended periods. The analysis in the literature has shown that the aerodynamic efficiency (cl/cd) of a corrugated aerofoil is sensitive to Reynolds number (Re) and angle-of-attack (AoA), yet the conclusions established are on the basis of flow analysis on a single baseline shape only. The sample size of the aerofoils must be extended further so that the influence and merits of corrugated shape features can be established. In this work, a design-of-experiments (DoE) approach is applied to induce systematic shape perturbations on a select, off-the-shelf baseline shape one feature at a time over a set number of increments. At each shape increment, the aerodynamic forces are established using a high fidelity CFD solver. The design space is modeled at a Re of 20,000 and 34,000 and at flow angle of 4.0° to represent a Micro Air Vehicle (MAV) in glide. The results confirmed the importance of the leading and trailing edge deflections on cl/cd. At Re = 20, 000, cl/cd of a corrugated aerofoil with deflection at the leading edge region only is 16% higher than the baseline shape, and 39% higher than the flat plate. At Re = 34, 000, cl/cd performance is sensitive to the trailing edge deflection. At the optimum deflection setting, cl/cd is 18% higher than the baseline shape and 23% higher than the flat plate. The results confirm that the leading and trailing edge deflections are critical to cl/cd for a MAV in glide.

  8. Dispersion of helically corrugated waveguides: Analytical, numerical, and experimental study

    NASA Astrophysics Data System (ADS)

    Burt, G.; Samsonov, S. V.; Ronald, K.; Denisov, G. G.; Young, A. R.; Bratman, V. L.; Phelps, A. D.; Cross, A. W.; Konoplev, I. V.; He, W.; Thomson, J.; Whyte, C. G.

    2004-10-01

    Helically corrugated waveguides have recently been studied for use in various applications such as interaction regions in gyrotron traveling-wave tubes and gyrotron backward-wave oscillators and as a dispersive medium for passive microwave pulse compression. The paper presents a summary of various methods that can be used for analysis of the wave dispersion of such waveguides. The results obtained from an analytical approach, simulations with the three-dimensional numerical code MAGIC, and cold microwave measurements are analyzed and compared.

  9. Corrugated outer sheath gas-insulated transmission line

    DOEpatents

    Kemeny, George A.; Cookson, Alan H.

    1981-01-01

    A gas-insulated transmission line includes two transmission line sections each of which are formed of a corrugated outer housing enclosing an inner high-voltage conductor disposed therein, with insulating support means supporting the inner conductor within the outer housing and an insulating gas providing electrical insulation therebetween. The outer housings in each section have smooth end sections at the longitudinal ends thereof which are joined together by joining means which provide for a sealing fixed joint.

  10. Evaporation characteristics of R22 flowing inside a corrugated tube

    SciTech Connect

    Hinton, D.L.; Conklin, J.C.; Vineyard, E.A.

    1992-07-01

    Because heat exchanger thermal performance has a direct influence on the overall cycle performance of vapor-compression refrigeration machinery, enhanced heat transfer surfaces are of interest to improve the efficiency of heat pumps and air conditioners. As part of a larger program investigating nonazeotropic refrigerant mixtures for replacement of chlorofluorocarbon compounds, we investigated the performance of R22 (chlorodifluoromethane) in conventional smooth tubes and enhanced heat transfer tube geometries as a base case. This paper presents the results of this initial investigation for a smooth tube and a tube with a commonly available enhanced heat transfer surface, called corrugated or spirally indented. We investigated the evaporating heat transfer and pressure drop characteristics in an experimental apparatus consisting of a variable-speed compressor and two sets of counterflow concentric-tube heat exchangers having both smooth and corrugated enhanced tubeside surfaces. The refrigerant circulates inside the central tube and water circulates in the annulus. The measured pressure drop and the heat transfer coefficient for the evaporation of the R22 are presented as a function of heat flux, quality, and mass flux for both heat transfer surfaces. Both the heat transfer coefficient and the pressure drop of the corrugated surface are higher than those of the smooth surface at any given refrigerant condition. The heat transfer enhancement is most notable at low mass qualities.

  11. PROCESSING OF NANOSTRUCTURED COPPER BY REPETITIVE CORRUGATION AND STRAIGHTENING (RCS)

    SciTech Connect

    Zhu, Y.T.; Jiang, H.

    2000-10-01

    A new process, Repetitive Corrugation and Straightening (RCS), has been developed to create bulk, nanostructured copper. In this investigation, a high purity (99.99%). copper bar measuring 6 x 6 x 50 mm with an average grain size of 765 {micro}m was used as the starting material. It was repetitively corrugated and straightened for 14 times with 90{degree} rotations along its longitudinal axis between consecutive corrugation-straightening cycles. The copper was cooled to below room temperature before each RCS cycle. The grain size obtained after the RCS process was in the range of twenty to a few hundred nanometers, and microhardness was increased by 100%. Both equilibrium and non-equilibrium grain boundaries are observed. This work demonstrates the capability of the RCS process in refining grain size of metal materials. The RCS process can be easily adapted to large-scale industrial production and has the potential to pave the way to large-scale structural applications of nanostructured materials.

  12. Experimental Investigation of the Strength of Multiweb Beams with Corrugated Webs

    NASA Technical Reports Server (NTRS)

    Fraser, Allister F

    1956-01-01

    The results of an experimental investigation of the strength of multiweb beams with corrugated webs are reported. Included in the investigation were two types of connection between the web and the skin. A comparison between the structural efficiency of corrugated-web and channel-web multiweb beams is presented, and it is shown that, for a considerable range of the structural index, corrugated-web beams can be built which are structurally more efficient than channel-web beams.

  13. Numerical exploration of the origin of aerodynamic enhancements in [low-Reynolds number] corrugated airfoils

    NASA Astrophysics Data System (ADS)

    Barnes, Caleb J.; Visbal, Miguel R.

    2013-11-01

    This paper explores the flow structure of a corrugated airfoil using a high-fidelity implicit large eddy simulation approach. The first three-dimensional simulations for a corrugated wing section are presented considering a range of Reynolds numbers of Rec = 5 × 103 to 5.8 × 104 bridging the gap left by previous numerical and experimental studies. Several important effects are shown to result from the corrugations in the leading-edge region. First, interaction between the detached shear layer and the first corrugation peak promotes recirculation upstream and enhances transition to turbulence due to flow instabilities. Thus, early transitional flow develops on the corrugated wing which helps to delay stall even at Reynolds numbers as low as Rec = 1 × 104. Transition is shown to occur as early as Rec = 7.5 × 103 and quickly advances toward the leading-edge as Reynolds number is increased. Modification of the first corrugation peak height produces significantly reduced separation and improved aerodynamic forces demonstrating the sensitivity of flow behavior to leading-edge geometry. Second, the unusual orientation of the corrugated surface and strong suction resulting from rapidly turning fluid over the separated region upstream of the first corrugation produces a new effect which serves to reduce drag. This effect was amplified through the enhanced interaction produced by a modified geometry. Corrugations were found to be most advantageous in the leading-edge region and could be optimized to properly take advantage of the flow field under different operating conditions.

  14. Outcoupling efficiency of OLEDs with 2D periodical corrugation at the cathode

    NASA Astrophysics Data System (ADS)

    Belousov, Sergei; Bogdanova, Maria; Teslyuk, Anton

    2016-03-01

    We study theoretically the optical performance of organic light-emitting diodes (OLEDs) with 2D periodical corrugation at the cathode. We show how emergence of radiative surface plasmon resonances at the 2D corrugated cathode leads to the enhancement of the outcoupling efficiency of the OLED, which is primarily due to the outcoupling of emission generated by vertically oriented emitting excitons in the emission layer. We analyze the outcoupling efficiency of the OLED as a function of geometrical parameters of the corrugation and establish design rules for optimal outcoupling enhancement with the 2D corrugation at the cathode.

  15. Ultrasonic pipe assessment

    DOEpatents

    Thomas, Graham H.; Morrow, Valerie L.; Levie, Harold; Kane, Ronald J.; Brown, Albert E.

    2003-12-23

    An ultrasonic pipe or other structure assessment system includes an ultrasonic transducer positioned proximate the pipe or other structure. A fluid connection between the ultrasonic transducer and the pipe or other structure is produced. The ultrasonic transducer is moved relative to the pipe or other structure.

  16. Surface-plasmon cross coupling in molecular fluorescence near a corrugated thin metal film

    NASA Technical Reports Server (NTRS)

    Gruhlke, R. W.; Holland, W. R.; Hall, D. G.

    1968-01-01

    Surface plasmons on opposite sides of a thin metal film can cross couple in the presence of a surface corrugation, or grating. The observation of this cross-coupling phenomenon as a radiative-decay mechanism for molecules near a corrugated thin metal film is reported.

  17. Three-dimensional train track model for study of rail corrugation

    NASA Astrophysics Data System (ADS)

    Jin, X. S.; Wen, Z. F.; Wang, K. Y.; Zhou, Z. R.; Liu, Q. Y.; Li, C. H.

    2006-06-01

    Rail corrugation is a main factor causing the vibration and noise from the structures of railway vehicles and tracks. A calculation model is put forward to analyse the effect of rail corrugation with different depths and wavelengths on the dynamical behaviour of a passenger car and a curved track in detail. Also the evolution of initial corrugation with different wavelengths is investigated. In the numerical analysis, Kalker's non-Hertzian rolling contact theory is modified and used to calculate the frictional work density on the contact area of the wheel and rail in rolling contact. The material loss per unit area is assumed to be proportional to the frictional work density to determine the wear depth of the contact surfaces of the curved rails. The combined influences of the corrugation development and the vertical and lateral coupled dynamics of the passenger car and the curved track are taken into account. The numerical results indicate that: (1) the corrugation with high passing frequencies has a great influence on the dynamical performance of the wheelset and track, but little on the car-body and the bogie frame; (2) the deeper the corrugation depth is, the greater the influence and the rail material wear are; but the longer the corrugation wavelength is, the smaller the influence and the wear are; and (3) the initial corrugation with a fixed wavelength on the rail running surface decreases with increasing number of the passenger car passages.

  18. Hydrogen sulfide removal from sediment and water in box culverts/storm drains by iron-based granules.

    PubMed

    Sun, J L; Shang, C; Kikkert, G A

    2013-01-01

    A renewable granular iron-based technology for hydrogen sulfide removal from sediment and water in box culverts and storm drains is discussed. Iron granules, including granular ferric hydroxide (GFH), granular ferric oxide (GFO) and rusted waste iron crusts (RWIC) embedded in the sediment phase removed aqueous hydrogen sulfide formed from sedimentary biological sulfate reduction. The exhausted iron granules were exposed to dissolved oxygen and this regeneration process recovered the sulfide removal capacities of the granules. The recovery is likely attributable to the oxidation of the ferrous iron precipitates film and the formation of new reactive ferric iron surface sites on the iron granules and sand particles. GFH and RWIC showed larger sulfide removal capacities in the sediment phase than GFO, likely due to the less ordered crystal structures on their surfaces. This study demonstrates that the iron granules are able to remove hydrogen sulfide from sediment and water in box culverts and storm drains and they have the potential to be regenerated and reused by contacting with dissolved oxygen.

  19. Hydrogen sulfide removal from sediment and water in box culverts/storm drains by iron-based granules.

    PubMed

    Sun, J L; Shang, C; Kikkert, G A

    2013-01-01

    A renewable granular iron-based technology for hydrogen sulfide removal from sediment and water in box culverts and storm drains is discussed. Iron granules, including granular ferric hydroxide (GFH), granular ferric oxide (GFO) and rusted waste iron crusts (RWIC) embedded in the sediment phase removed aqueous hydrogen sulfide formed from sedimentary biological sulfate reduction. The exhausted iron granules were exposed to dissolved oxygen and this regeneration process recovered the sulfide removal capacities of the granules. The recovery is likely attributable to the oxidation of the ferrous iron precipitates film and the formation of new reactive ferric iron surface sites on the iron granules and sand particles. GFH and RWIC showed larger sulfide removal capacities in the sediment phase than GFO, likely due to the less ordered crystal structures on their surfaces. This study demonstrates that the iron granules are able to remove hydrogen sulfide from sediment and water in box culverts and storm drains and they have the potential to be regenerated and reused by contacting with dissolved oxygen. PMID:24355850

  20. The biofouling potential of flow on corrugated surfaces

    NASA Astrophysics Data System (ADS)

    Miño, Gastón L.; Rusconi, Roberto; Kantsler, Vasily; Stocker, Roman

    2015-11-01

    Both natural and man-made surfaces are rarely smooth, and are instead often characterized by geometric heterogeneity or roughness over a broad range of scales. Because of the predicted importance of the local interaction between microorganisms and surfaces, roughness at the microbial scale can be an important element in determining the outcome of microbe-surface interactions, which represent the first step in biofilm formation and biofouling. In microbial habitats this interaction often occurs in flowing fluids, which can be important because regions with high hydrodynamic shear can induce a strong reorientation of bacteria towards surfaces, promoting attachment. Here we study the combination of flow and surface topography using video microscopy of Escherichia coli in corrugated microfluidic channels. We report that flow preferentially promotes attachment to specific regions of a corrugated surface, as result of the hydrodynamics of bacteria swimming in flow. We compute from the data a ``Local Biofouling Potential'' (LBP) and compare this successfully with predictions of a mathematical model, yielding one step towards the ability to mechanistically predict and thus ultimately either prevent or induce biofouling.

  1. Imaging Local Electronic Corrugations and Doped Regions in Graphene

    SciTech Connect

    B Schultz; C Patridge; V Lee; C Jaye; P Lysaght; C Smith; J Barnett; D Fischer; D Prendergast; S Banerjee

    2011-12-31

    Electronic structure heterogeneities are ubiquitous in two-dimensional graphene and profoundly impact the transport properties of this material. Here we show the mapping of discrete electronic domains within a single graphene sheet using scanning transmission X-ray microscopy in conjunction with ab initio density functional theory calculations. Scanning transmission X-ray microscopy imaging provides a wealth of detail regarding the extent to which the unoccupied levels of graphene are modified by corrugation, doping and adventitious impurities, as a result of synthesis and processing. Local electronic corrugations, visualized as distortions of the {pi}*cloud, have been imaged alongside inhomogeneously doped regions characterized by distinctive spectral signatures of altered unoccupied density of states. The combination of density functional theory calculations, scanning transmission X-ray microscopy imaging, and in situ near-edge X-ray absorption fine structure spectroscopy experiments also provide resolution of a longstanding debate in the literature regarding the spectral assignments of pre-edge and interlayer states.

  2. Corrugated Waveguide Mode Content Analysis Using Irradiance Moments

    PubMed Central

    Jawla, Sudheer K.; Shapiro, Michael A.; Idei, Hiroshi; Temkin, Richard J.

    2015-01-01

    We present a novel, relatively simple method for determining the mode content of the linearly polarized modes of a corrugated waveguide using the moments of the intensity pattern of the field radiated from the end of the waveguide. This irradiance moment method is based on calculating the low-order irradiance moments, using measured intensity profiles only, of the radiated field from the waveguide aperture. Unlike the phase retrieval method, this method does not use or determine the phase distribution at the waveguide aperture. The new method was benchmarked numerically by comparison with sample mode mixtures. The results predict less than ±0.7% error bar in the retrieval of the mode content. The method was also tested using high-resolution experimental data from beams radiated from 63.5 mm and 19 mm corrugated waveguides at 170 and 250 GHz, respectively. The results showed a very good agreement of the mode content retrieved using the irradiance moment method versus the phase retrieval technique. The irradiance moment method is most suitable for cases where the modal power is primarily in the fundamental HE11 mode, with <8% of the power in high-order modes. PMID:25821260

  3. Insulated pipe clamp design

    SciTech Connect

    Anderson, M.J.; Hyde, L.L.; Wagner, S.E.; Severud, L.K.

    1980-01-01

    Thin wall large diameter piping for breeder reactor plants can be subjected to significant thermal shocks during reactor scrams and other upset events. On the Fast Flux Test Facility, the addition of thick clamps directly on the piping was undesired because the differential metal temperatures between the pipe wall and the clamp could have significantly reduced the pipe thermal fatigue life cycle capabilities. Accordingly, an insulated pipe clamp design concept was developed. The design considerations and methods along with the development tests are presented. Special considerations to guard against adverse cracking of the insulation material, to maintain the clamp-pipe stiffness desired during a seismic event, to minimize clamp restraint on the pipe during normal pipe heatup, and to resist clamp rotation or spinning on the pipe are emphasized.

  4. Flexible ocean upwelling pipe

    DOEpatents

    Person, Abraham

    1980-01-01

    In an ocean thermal energy conversion facility, a cold water riser pipe is releasably supported at its upper end by the hull of the floating facility. The pipe is substantially vertical and has its lower end far below the hull above the ocean floor. The pipe is defined essentially entirely of a material which has a modulus of elasticity substantially less than that of steel, e.g., high density polyethylene, so that the pipe is flexible and compliant to rather than resistant to applied bending moments. The position of the lower end of the pipe relative to the hull is stabilized by a weight suspended below the lower end of the pipe on a flexible line. The pipe, apart from the weight, is positively buoyant. If support of the upper end of the pipe is released, the pipe sinks to the ocean floor, but is not damaged as the length of the line between the pipe and the weight is sufficient to allow the buoyant pipe to come to a stop within the line length after the weight contacts the ocean floor, and thereafter to float submerged above the ocean floor while moored to the ocean floor by the weight. The upper end of the pipe, while supported by the hull, communicates to a sump in the hull in which the water level is maintained below the ambient water level. The sump volume is sufficient to keep the pipe full during heaving of the hull, thereby preventing collapse of the pipe.

  5. Reusable pipe flange covers

    DOEpatents

    Holden, James Elliott; Perez, Julieta

    2001-01-01

    A molded, flexible pipe flange cover for temporarily covering a pipe flange and a pipe opening includes a substantially round center portion having a peripheral skirt portion depending from the center portion, the center portion adapted to engage a front side of the pipe flange and to seal the pipe opening. The peripheral skirt portion is formed to include a plurality of circumferentially spaced tabs, wherein free ends of the flexible tabs are formed with respective through passages adapted to receive a drawstring for pulling the tabs together on a back side of the pipe flange.

  6. Flood magnitude and frequency of Jacks Run at the culvert on U.S. Route 206, Southampton Township, Burlington County, New Jersey

    USGS Publications Warehouse

    Barringer, Thomas

    1996-01-01

    Flood magnitude and frequency of Jacks Run at the culvert on U.S. Route 206, Southampton Township, New Jersey, were determined by using the rational method. Flood magnitude and frequency estimates, as well as basin characteristics, are included in this report. The 100-year-flood estimate is 29 cubic feet per second.

  7. Modeling of a corrugated dielectric elastomer actuator for artificial muscle applications

    NASA Astrophysics Data System (ADS)

    Kadooka, Kevin; Taya, Minoru; Naito, Keishi; Saito, Makoto

    2015-04-01

    Dielectric elastomer actuators have many advantages, including light weight, simplicity, high energy density, and silent operation. These features make them suitable to replace conventional actuators and transducers, especially in artificial muscle applications where large contractile strains are necessary for lifelike motions. This paper will introduce the concept of a corrugated dielectric elastomer actuator (DEA), which consists of dielectric elastomer (DE) laminated to a thin elastic layer to induce bending motion at each of the corrugations, resulting in large axial deformation. The location of the DE and elastic layers can be configured to provide tensile or compressive axial strain. Such corrugated DE actuators are also highly scalable: linking multiple actuators in series results in greater deformation, whereas multiple actuators in parallel results in larger force output. Analytical closed-form solutions based on linear elasticity were derived for the displacement and force output of curved unimorph and corrugated DEA, both consisting of an arbitrary number of lamina. A total strain energy analysis and Castigiliano's theorem were used to predict the nonlinear force-displacement behavior of the corrugated actuator. Curved unimorph and corrugated DEA were fabricated using VHB F9469PC as the DE material. Displacement of the actuators observed during testing agreed well with the modeling results. Large contractile strain (25.5%) was achieved by the corrugated DEA. Future work includes investigating higher performance DE materials such as plasticized PVDF terpolymers, processed by thin film deposition methods.

  8. Study on rail corrugation of a metro tangential track with Cologne-egg type fasteners

    NASA Astrophysics Data System (ADS)

    Cui, X. L.; Chen, G. X.; Yang, H. G.; Zhang, Q.; Ouyang, H.; Zhu, M. H.

    2016-03-01

    In Chinese metro lines, rail corrugation on both tangential and tight curved tracks with Cologne-egg type fasteners is very severe. Based on the viewpoint of friction-induced vibration causing rail corrugation, the rail corrugation on a tangential track with Cologne-egg type fasteners is studied in this paper. A vibration model of an elastic multiple-wheelset-track system with Cologne-egg type fasteners is established. Both the complex eigenvalue analysis and the transient dynamic analysis are performed to study the stability and the dynamic performance of the wheelset-track system. The simulation results show that a low rail support stiffness value is responsible for rail corrugation on the tangential track. When the Cologne-egg fasteners characterised by a lower stiffness value are replaced with the DTVI2 fasteners characterised by a higher stiffness value, rail corrugation disappears. However, rail corrugation on tight curved tracks cannot be suppressed using the same replacement. The above conclusions are consistent with the corrugation occurrences in actual metro tracks.

  9. Numerical investigation of the aerodynamic and structural characteristics of a corrugated wing

    NASA Astrophysics Data System (ADS)

    Hord, Kyle

    Previous experimental studies on static, bio-inspired corrugated wings have shown that they produce favorable aerodynamic properties such as delayed stall compared to streamlined wings and flat plates at high Reynolds numbers (Re ≥ 4x104). The majority of studies have been carried out with scaled models of dragonfly forewings from the Aeshna Cyanea in either wind tunnels or water channels. In this thesis, the aerodynamics of a corrugated airfoil was studied using computational fluid dynamics methods at a low Reynolds number of 1000. Structural analysis was also performed using the commercial software SolidWorks 2009. The flow field is described by solving the incompressible Navier-Stokes equations on an overlapping grid using the pressure-Poisson method. The equations are discretized in space with second-order accurate central differences. Time integration is achieved through the second-order Crank-Nicolson implicit method. The complex vortex structures that form in the corrugated airfoil valleys and around the corrugated airfoil are studied in detail. Comparisons are made with experimental measurements from corrugated wings and also with simulations of a flat plate. Contrary to the studies at high Reynolds numbers, our study shows that at low Reynolds numbers the wing corrugation does not provide any aerodynamic benefit compared to a smoothed flat plate. Instead, the corrugated profile generates more pressure drag which is only partially offset by the reduction of friction drag, leading to more total drag than the flat plate. Structural analysis shows that the wing corrugation can increase the resistance to bending moments on the wing structure. A smoothed structure has to be three times thicker to provide the same stiffness. It was concluded the corrugated wing has the structural benefit to provide the same resistance to bending moments with a much reduced weight.

  10. Geometrical properties of turbulent premixed flames and other corrugated interfaces

    NASA Astrophysics Data System (ADS)

    Thiesset, F.; Maurice, G.; Halter, F.; Mazellier, N.; Chauveau, C.; Gökalp, I.

    2016-01-01

    This study focuses on the geometrical properties of turbulent flame fronts and other interfaces. Toward that end, we use an original tool based on proper orthogonal decomposition (POD), which is applied to the interface spatial coordinates. The focus is mainly on the degree of roughness of the flame front, which is quantified through the scale dependence of its coverage arclength. POD is first validated by comparing with the caliper technique. Fractal characteristics are extracted in an unambiguous fashion using a parametric expression which appears to be impressively well suited for representing Richardson plots. Then it is shown that, for the range of Reynolds numbers investigated here, the scale-by-scale contribution to the arclength does not comply with scale similarity, irrespectively of the type of similarity which is invoked. The finite ratios between large and small scales, referred to as finite Reynolds number effects, are likely to explain this observation. In this context, the Reynolds number that ought to be achieved for a proper inertial range to be discernible, and for scale similarity to be likely to apply, is calculated. Fractal characteristics of flame folding are compared to available predictions. It is confirmed that the inner cutoff satisfactorily correlates with the Kolmogorov scale while the outer cutoff appears to be proportional to the integral length scale. However, the scaling for the fractal dimension is much less obvious. It is argued that much higher Reynolds numbers have to be reached for drawing firm statements about the evolution (or constancy) of the fractal dimension with respect to flame and flow parameters. Finally, a heuristic phenomenology of corrugated interfaces is highlighted. The degree of generality of the latter phenomenology is confirmed by comparing the folding of different interfaces including a turbulent-nonturbulent interface, a liquid jet destabilized by a surrounding air jet, a cavitating flow, and an isoscalar

  11. Geometrical properties of turbulent premixed flames and other corrugated interfaces.

    PubMed

    Thiesset, F; Maurice, G; Halter, F; Mazellier, N; Chauveau, C; Gökalp, I

    2016-01-01

    This study focuses on the geometrical properties of turbulent flame fronts and other interfaces. Toward that end, we use an original tool based on proper orthogonal decomposition (POD), which is applied to the interface spatial coordinates. The focus is mainly on the degree of roughness of the flame front, which is quantified through the scale dependence of its coverage arclength. POD is first validated by comparing with the caliper technique. Fractal characteristics are extracted in an unambiguous fashion using a parametric expression which appears to be impressively well suited for representing Richardson plots. Then it is shown that, for the range of Reynolds numbers investigated here, the scale-by-scale contribution to the arclength does not comply with scale similarity, irrespectively of the type of similarity which is invoked. The finite ratios between large and small scales, referred to as finite Reynolds number effects, are likely to explain this observation. In this context, the Reynolds number that ought to be achieved for a proper inertial range to be discernible, and for scale similarity to be likely to apply, is calculated. Fractal characteristics of flame folding are compared to available predictions. It is confirmed that the inner cutoff satisfactorily correlates with the Kolmogorov scale while the outer cutoff appears to be proportional to the integral length scale. However, the scaling for the fractal dimension is much less obvious. It is argued that much higher Reynolds numbers have to be reached for drawing firm statements about the evolution (or constancy) of the fractal dimension with respect to flame and flow parameters. Finally, a heuristic phenomenology of corrugated interfaces is highlighted. The degree of generality of the latter phenomenology is confirmed by comparing the folding of different interfaces including a turbulent-nonturbulent interface, a liquid jet destabilized by a surrounding air jet, a cavitating flow, and an isoscalar

  12. Bending of five-layer beams with lengthwise corrugated main core

    SciTech Connect

    Magnucka-Blandzi, Ewa; Walczak, Zbigniew

    2015-03-10

    The paper is devoted to one orthotropic thin-walled sandwich beam with trapezoidal core and two-layer facings. The inner layers of the facings are also corrugated. The orientation of the corrugations of the inner layers of the facings is perpendicular to trapezoidal corrugation of the beam core. The mathematical and physical model of this beam is formulated, and also the field of displacements. Basing on the principle of the total potential energy the system of equilibrium equations is derived. The analytical solutions will be verified numerically with the use of the finite element method (MES)

  13. Gyrokinetic simulations of off-axis minimum-q profile corrugations

    SciTech Connect

    Waltz, R.E.; Austin, M.E.; Burrell, K.H.; Candy, J.

    2006-05-15

    Quasiequilibrium radial 'profile corrugations' in the electron temperature gradient are found at lowest-order singular surfaces in global gyrokinetic code simulations of both monotonic-q and off-axis minimum-q discharges. The profile corrugations in the temperature and density gradients are time-averaged components of zonal flows. The m/n=2/1 electron temperature gradient corrugation is measurably large and appears to trigger an internal transport barrier as the off-axis minimum-q=2 surfaces enter the plasma.

  14. Experimental and analytical determination of vibration characteristics of corrugated, flexibly supported, heat-shield panels

    NASA Technical Reports Server (NTRS)

    Carden, H. D.

    1974-01-01

    Experimental and analytical natural frequencies, nodal patterns, and typical modal displacements for a corrugated, flexibly supported, heat-shield panel are discussed. Good correlation was found between the experimental data and NASTRAN analytical results for the corrugated panel over a relatively wide frequency spectrum covered in the investigation. Of the two experimental techniques used for mode shape and displacement measurements (a noncontacting displacement sensor system and a holographic technique using a helium-neon, continuous-wave laser), the holographic technique was found, in the present investigation, to be faster and better suited for determining a large number of complex nodal patterns of the corrugated panel.

  15. Pipe-to-pipe impact program

    SciTech Connect

    Alzheimer, J.M.; Bampton, M.C.C.; Friley, J.R.; Simonen, F.A.

    1984-06-01

    This report documents the tests and analyses performed as part of the Pipe-to-Pipe Impact (PTPI) Program at the Pacific Northwest Laboratory. This work was performed to assist the NRC in making licensing decisions regarding pipe-to-pipe impact events following postulated breaks in high energy fluid system piping. The report scope encompasses work conducted from the program's start through the completion of the initial hot oil tests. The test equipment, procedures, and results are described, as are analytic studies of failure potential and data correlation. Because the PTPI Program is only partially completed, the total significance of the current test results cannot yet be accurately assessed. Therefore, although trends in the data are discussed, final conclusions and recommendations will be possible only after the completion of the program, which is scheduled to end in FY 1984.

  16. Heat pipes. [technology utilization

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The development and use of heat pipes are described, including space requirements and contributions. Controllable heat pipes, and designs for automatically maintaining a selected constant temperature, are discussed which would add to the versatility and usefulness of heat pipes in industrial processing, manufacture of integrated circuits, and in temperature stabilization of electronics.

  17. Assessment of scour-critical data collected at selected bridges and culverts in South Carolina, 1990-92

    USGS Publications Warehouse

    Hurley, N.M., Jr.

    1996-01-01

    Data at bridges and culverts were collected at 3,506 stream crossings in South Carolina during 1990-92. The data include general information unique to the structure; structural data; and hydraulic, geomorphic, and vegetation information. The data are stored in the U.S. Geological Survey South Carolina District Bridge-Scour Data Base. Observed- and potential-scour indexes were computed from the applicable data variables. Sites with observed-scour indexes exceeding ten and (or) potential-scour indexes exceeding 20 are considered to have significant scour-related problems. Of the 3,506 sites inspected, 257 sites had an observed-scour index exceeding ten, 214 sites had a potential-scour index exceeding 20, and 85 sites had observed- and potential-scour indexes exceeding both threshold values.

  18. Overall Thermal Performance of Flexible Piping Under Simulated Bending Conditions

    NASA Technical Reports Server (NTRS)

    Fesmire, James E.; Augustynowicz, S. D.; Demko, J. A.; Thompson, Karen (Technical Monitor)

    2001-01-01

    Flexible, vacuum-insulated transfer lines for low-temperature applications have higher thermal losses than comparable rigid lines. Typical flexible piping construction uses corrugated tubes, inner and outer, with a multilayer insulation (MLI) system in the annular space. Experiments on vacuum insulation systems in a flexible geometry were conducted at the Cryogenics Test Laboratory of NASA Kennedy Space Center. The effects of bending were simulated by causing the inner tube to be eccentric with the outer tube. The effects of spacers were simulated in a controlled way by inserting spacer tubes for the length of the cylindrical test articles. Two material systems, standard MLI and a layered composite insulation (LCI), were tested under the full range of vacuum levels using a liquid nitrogen boiloff calorimeter to determine the apparent thermal conductivity (k-value). The results indicate that the flexible piping under simulated bending conditions significantly degrades the thermal performance of the insulation system. These data are compared to standard MLI for both straight and flexible piping configurations. The definition of an overall k-value for actual field installations (k(sub oafi)) is described for use in design and analysis of cryogenic piping systems.

  19. BNL piping research

    SciTech Connect

    Bezler, P.; Subudhi, M.; Wang, Y.K.; Shteyngart, S.

    1985-01-01

    Brookhaven National Laboratory (BNL) has assisted in the development of methods to evaluate the analysis methods used by industry to qualify nuclear power piping. Through FY 1985 these efforts were conducted under the Mechanical Piping Benchmarks project while current and future efforts will be performed under the Combination Procedures for piping project. Under these projects BNL has developed analytical benchmark problems for piping systems evaluated using uniform or independent support motion response spectrum methods, investigated the adequacy and limitations of linear piping analysis methods by comparison to test results and evaluated and developed criteria for new and alternate methods of analysis. A summary description of the status of these efforts is provided.

  20. Pipe Line Control

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The array of tanks, pipes and valves in the photo below is a petroleum tank farm in Georgia, part of a petrochemical pipe line system that moves refined petroleum products from Texas and Louisiana to the mid-Eastern seaboard. The same pipes handle a number of different products, such as gasoline, kerosene, jet fuel or fuel oil. The fluids are temporarily stored in tanks, pumped into the pipes in turn and routed to other way stations along the pipe line. The complex job of controlling, measuring and monitoring fuel flow is accomplished automatically by a computerized control and communications system which incorporates multiple space technologies.

  1. Corrugated velocity patterns in the spiral galaxies: NGC 278, NGC 1058, NGC 2500 & UGC 3574 .

    NASA Astrophysics Data System (ADS)

    Sánchez Gil, M. C.; Alfaro, E. J.; Pérez, E.

    In this work we address the study of the detection in Halpha of a radial corrugation in the vertical velocity field in a sample of four nearly face-on, spiral galaxies. The geometry of the problem is a main criterion in the selection of the sample as well as of the azimuthal angle of the slits. These spatial corrugations must be equally associated with wavy vertical motions in the galactic plane with a strong large-scale consistency. Evidence of these kinematic waves were first detected in the analysis of the rotation curves of spiral galaxies (eg Vaucoleurs & de Vaucaleurs 1963, Pismis 1965), but it was not until 2001 that Alfaro et al. analyzed in more detail the velocity corrugations in NGC 5427 and a possible physical mechanism for their origin. The aim of this study is to analyze the corrugated velocity pattern in terms of the star formation processes. We describe the geometry of the problem and establish its fundamental relationships.

  2. Trapping surface plasmon polaritons on ultrathin corrugated metallic strips in microwave frequencies.

    PubMed

    Yang, Yan; Shen, Xiaopeng; Zhao, Pei; Zhang, Hao Chi; Cui, Tie Jun

    2015-03-23

    It has been demonstrated that an ultrathin uniformly corrugated metallic strip is a good plasmonic waveguide in microwave and terahertz frequencies to propagate spoof surface plasmon polaritons (SPPs) with well confinement and small loss (Shen et al., PNAS 110, 40-45, 2013). Here, we propose a simple method to trap SPP waves on the ultrathin corrugated metallic strips in broad band in the microwave frequencies. By properly designing non-uniform corrugations with gradient-depth grooves, we show that the SPP waves are slowed down gradually and then reflected at pre-designed positions along the ultrathin metallic strip when the frequency varies. We design and fabricate the ultrathin gradient-corrugation metallic strip on a thin dielectric film. Both numerical simulation and measurement results validate the efficient trapping of SPP waves in broadband from 9 to 14 GHz. This proposal is a promising candidate for slow-wave devices in both microwave and terahertz regimes. PMID:25837047

  3. Development of a model for flaming combustion of double-wall corrugated cardboard

    NASA Astrophysics Data System (ADS)

    McKinnon, Mark B.

    Corrugated cardboard is used extensively in a storage capacity in warehouses and frequently acts as the primary fuel for accidental fires that begin in storage facilities. A one-dimensional numerical pyrolysis model for double-wall corrugated cardboard was developed using the Thermakin modeling environment to describe the burning rate of corrugated cardboard. The model parameters corresponding to the thermal properties of the corrugated cardboard layers were determined through analysis of data collected in cone calorimeter tests conducted with incident heat fluxes in the range 20--80 kW/m 2. An apparent pyrolysis reaction mechanism and thermodynamic properties for the material were obtained using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The fully-parameterized bench-scale model predicted burning rate profiles that were in agreement with the experimental data for the entire range of incident heat fluxes, with more consistent predictions at higher heat fluxes.

  4. Leaky-Wave Radiations by Modulating Surface Impedance on Subwavelength Corrugated Metal Structures.

    PubMed

    Cai, Ben Geng; Li, Yun Bo; Ma, Hui Feng; Jiang, Wei Xiang; Cheng, Qiang; Cui, Tie Jun

    2016-01-01

    One-dimensional (1D) subwavelength corrugated metal structures has been described to support spoof surface plasmon polaritons (SPPs). Here we demonstrate that a periodically modulated 1D subwavelength corrugated metal structure can convert spoof SPPs to propagating waves. The structure is fed at the center through a slit with a connected waveguide on the input side. The subwavelength corrugated metal structure on the output surface is regarded as metasurface and modulated periodically to realize the leaky-wave radiation at the broadside. The surface impedance of the corrugated metal structure is modulated by using cosine function and triangle-wave function, respectively, to reach the radiation effect. Full wave simulations and measuremental results are presented to validate the proposed design. PMID:27035269

  5. Leaky-Wave Radiations by Modulating Surface Impedance on Subwavelength Corrugated Metal Structures

    PubMed Central

    Cai, Ben Geng; Li, Yun Bo; Ma, Hui Feng; Jiang, Wei Xiang; Cheng, Qiang; Cui, Tie Jun

    2016-01-01

    One-dimensional (1D) subwavelength corrugated metal structures has been described to support spoof surface plasmon polaritons (SPPs). Here we demonstrate that a periodically modulated 1D subwavelength corrugated metal structure can convert spoof SPPs to propagating waves. The structure is fed at the center through a slit with a connected waveguide on the input side. The subwavelength corrugated metal structure on the output surface is regarded as metasurface and modulated periodically to realize the leaky-wave radiation at the broadside. The surface impedance of the corrugated metal structure is modulated by using cosine function and triangle-wave function, respectively, to reach the radiation effect. Full wave simulations and measuremental results are presented to validate the proposed design. PMID:27035269

  6. 5. Detail, 5panel door and corrugated metal siding, Oil House, ...

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

    5. Detail, 5-panel door and corrugated metal siding, Oil House, Southern Pacific Railroad Carlin Shops, southwest facade, view to northeast (210mm lens). - Southern Pacific Railroad, Carlin Shops, Oil House, Foot of Sixth Street, Carlin, Elko County, NV

  7. Bending Tests of Circular Cylinders of Corrugated Aluminum-alloy Sheet

    NASA Technical Reports Server (NTRS)

    Buckwalter, John C; Reed, Warren D; Niles, Alfred S

    1937-01-01

    Bending tests were made of two circular cylinders of corrugated aluminum-alloy sheet. In each test failure occurred by bending of the corrugations in a plane normal to the skin. It was found, after analysis of the effect of short end bays, that the computed stress on the extreme fiber of a corrugated cylinder is in excess of that for a flat panel of the same basic pattern and panel length tested as a pin-ended column. It is concluded that this increased strength was due to the effects of curvature of the pitch line. It is also concluded from the tests that light bulkheads closely spaced strengthen corrugated cylinders very materially.

  8. 14. DETAIL OF SOUTHWEST FRONT OF WAREHOUSE, SHOWING CORRUGATED PLASTER/ASBESTOS ...

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

    14. DETAIL OF SOUTHWEST FRONT OF WAREHOUSE, SHOWING CORRUGATED PLASTER/ASBESTOS WALLS, WINDOWS AND ROOF. VIEW TO NORTHEAST. - Commercial & Industrial Buildings, International Harvester Company Showroom, Office & Warehouse, 10 South Main Street, Dubuque, Dubuque County, IA

  9. Impedance modelling of pipes

    NASA Astrophysics Data System (ADS)

    Creasy, M. Austin

    2016-03-01

    Impedance models of pipes can be used to estimate resonant frequencies of standing waves and model acoustic pressure of closed and open ended pipes. Modelling a pipe with impedance methods allows additional variations to the pipe to be included in the overall model as a system. Therefore an actuator can be attached and used to drive the system and the impedance model is able to include the dynamics of the actuator. Exciting the pipe system with a chirp signal allows resonant frequencies to be measured in both the time and frequency domain. The measurements in the time domain are beneficial for introducing undergraduates to resonances without needing an understanding of fast Fourier transforms. This paper also discusses resonant frequencies in open ended pipes and how numerous texts incorrectly approximate the resonant frequencies for this specific pipe system.

  10. Critical instability and friction scaling of fluid flows through pipes with rough inner surfaces.

    PubMed

    Tao, Jianjun

    2009-12-31

    It has been shown experimentally over nearly 80 years that surface fine roughness of circular pipes has a crucial effect on the natural transition to turbulence. In this Letter, a theoretical explanation is suggested for the roughness-induced instability. Once the nonlinear effect of roughness is introduced (through a pipe with fine corrugation surface), the mean velocity profile becomes unstable to three-dimensional, asymmetric, and helical traveling waves at moderate Reynolds numbers. The threshold of the aspect ratio or shape factor of the roughness element required to cause instability scales as Re-2. Inspired by the current model, a scaling form is proposed and the scaled friction factor measurements in rough pipes collapse onto a universal curve.

  11. Numerical and Experimental Investigations on Mechanical Behavior of Composite Corrugated Core

    NASA Astrophysics Data System (ADS)

    Dayyani, Iman; Ziaei-Rad, Saeed; Salehi, Hamid

    2012-06-01

    Tensile and flexural characteristics of corrugated laminate panels were studied using numerical and analytical methods and compared with experimental data. Prepreg laminates of glass fiber plain woven cloth were hand-laid by use of a heat gun to ease the creation of the panel. The corrugated panels were then manufactured by using a trapezoidal machined aluminium mould. First, a series of simple tension tests were performed on standard samples to evaluate the material characteristics. Next, the corrugated panels were subjected to tensile and three-point bending tests. The force-displacement graphs were recorded. Numerical and analytical solutions were proposed to simulate the mechanical behavior of the panels. In order to model the energy dissipation due to delamination phenomenon observed in tensile tests in all members of corrugated core, plastic behavior was assigned to the whole geometry, not only to the corner regions. Contrary to the literature, it is shown that the three-stage mechanical behavior of composite corrugated core is not confined to aramid reinforced corrugated laminates and can be observed in other types such as fiber glass. The results reveal that the mechanical behavior of the core in tension is sensitive to the variation of core height. In addition, for the first time, the behavior of composite corrugated core was studied and verified in bending. Finally, the analytical and numerical results were validated by comparing them with experimental data. A good degree of correlation was observed which showed the suitability of the finite element model for predicting the mechanical behavior of corrugated laminate panels.

  12. Numerical analysis of bio-inspired corrugated airfoil at low Reynolds number

    NASA Astrophysics Data System (ADS)

    Mondal, Partha Protim; Rahman, Md. Masudur; Hasan, A. B. M. Toufique

    2016-07-01

    A numerical study was conducted to investigate the aerodynamic performance of a bio-inspired corrugated airfoil at the chord Reynolds number of Rec=80,000 to explore the potential advantages of such airfoils at low Reynolds numbers. This study represents the transient nature of corrugated airfoils at low Reynolds number where flow is assumed to be laminar, unsteady, incompressible and two dimensional. The simulations include a sharp interface Cartesian grid based meshing employed with laminar viscous model. The flow field surrounding the corrugated airfoil has been analyzed using structured grid Finite Volume Method (FVM) based on Navier-Stokes equation. All parameters used in flow simulation are expressed in non-dimensional quantities for better understanding of flow behavior, regardless of dimensions or the fluid that is used. The simulated results revealed that the corrugated airfoil provides high lift with moderate drag and prevents large scale flow separation at higher angles of attack. This happens due to the negative shear drag produced by the recirculation zones which occurs in the valleys of the corrugated airfoils. The existence of small circulation bubbles sitting in the valleys prevents large scale flow separation thus increasing the aerodynamic performance of the corrugated airfoil.

  13. Geometrical properties of turbulent premixed flames and other corrugated interfaces.

    PubMed

    Thiesset, F; Maurice, G; Halter, F; Mazellier, N; Chauveau, C; Gökalp, I

    2016-01-01

    This study focuses on the geometrical properties of turbulent flame fronts and other interfaces. Toward that end, we use an original tool based on proper orthogonal decomposition (POD), which is applied to the interface spatial coordinates. The focus is mainly on the degree of roughness of the flame front, which is quantified through the scale dependence of its coverage arclength. POD is first validated by comparing with the caliper technique. Fractal characteristics are extracted in an unambiguous fashion using a parametric expression which appears to be impressively well suited for representing Richardson plots. Then it is shown that, for the range of Reynolds numbers investigated here, the scale-by-scale contribution to the arclength does not comply with scale similarity, irrespectively of the type of similarity which is invoked. The finite ratios between large and small scales, referred to as finite Reynolds number effects, are likely to explain this observation. In this context, the Reynolds number that ought to be achieved for a proper inertial range to be discernible, and for scale similarity to be likely to apply, is calculated. Fractal characteristics of flame folding are compared to available predictions. It is confirmed that the inner cutoff satisfactorily correlates with the Kolmogorov scale while the outer cutoff appears to be proportional to the integral length scale. However, the scaling for the fractal dimension is much less obvious. It is argued that much higher Reynolds numbers have to be reached for drawing firm statements about the evolution (or constancy) of the fractal dimension with respect to flame and flow parameters. Finally, a heuristic phenomenology of corrugated interfaces is highlighted. The degree of generality of the latter phenomenology is confirmed by comparing the folding of different interfaces including a turbulent-nonturbulent interface, a liquid jet destabilized by a surrounding air jet, a cavitating flow, and an isoscalar

  14. 65. FIRE SUPPRESSION PIPES BEHIND FLAME BUCKET. PIPES TO UMBILICAL ...

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

    65. FIRE SUPPRESSION PIPES BEHIND FLAME BUCKET. PIPES TO UMBILICAL MAST IN LOWER LEFT CORNER; PIPES TO LAUNCHER IN UPPER LEFT CORNER; PIPES TO FLAME BUCKET IN LOWER RIGHT CORNER OF PHOTOGRAPH. POTABLE WATER PIPING IN UPPER RIGHT CORNER OF PHOTO. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  15. Spreading of droplet with insoluble surfactant on corrugated topography

    NASA Astrophysics Data System (ADS)

    Li, Chunxi; Pei, Jianjun; Ye, Xuemin

    2014-09-01

    The flow of microscale fluid on a topography surface is a key to further development of MEMS, nanoscience and technology. In the present paper, a theoretical model of the droplet spreading with insoluble surfactant over corrugated topography is established with the lubrication theory, and the evolution equations of film thickness and surfactant concentration in base state and disturbance state are formulated. The droplet dynamics, the nonlinear stability based on nonmodal stability theory, and the effects of topography structure and Marangoni stress are numerically simulated with PDECOL scheme. Results show that the impact of topographical surface is strengthened apparently while the Marangoni stress driven by surfactant concentration is weakened in the mid-late stages of the spreading. The droplet radius on the topography advances faster and the lowest height of liquid/gas interface near the droplet edge reduces remarkably in the intermediate stage compared with those on the flat wall. The quantity of the wavelet similar to the topography increases gradually, with the characteristics of wavelet crest height with time exhibiting a single-hump feature. The spreading stability is enhanced under the disturbance wavenumber of 4, however, is to deteriorate and even to transform into instability when wavenumber increases further. In addition, the reductive Marangoni number, enhancive capillary number, modest Peclet number, the low height of the topography as well as small wavenumber of topography can make contributions to the evident stability of droplet spreading.

  16. The corrugation instability of a piston-driven shock wave

    NASA Astrophysics Data System (ADS)

    Bates, Jason

    2014-10-01

    We investigate the dynamics of a shock wave that is driven into an inviscid fluid by the steady motion of a two-dimensional planar piston with small corrugations on its surface. This problem was first considered by Freeman [Proc. Royal Soc. A. 228, 341 (1955)], who showed that piston-driven shocks are unconditionally stable when the medium through which they propagate is an ideal gas. Here, we generalize his work to account for a fluid with an arbitrary equation of state. We find that shocks are stable when - 1 < h

  17. Dispersionless Manipulation of Reflected Acoustic Wavefront by Subwavelength Corrugated Surface

    PubMed Central

    Zhu, Yi-Fan; Zou, Xin-Ye; Li, Rui-Qi; Jiang, Xue; Tu, Juan; Liang, Bin; Cheng, Jian-Chun

    2015-01-01

    Free controls of optic/acoustic waves for bending, focusing or steering the energy of wavefronts are highly desirable in many practical scenarios. However, the dispersive nature of the existing metamaterials/metasurfaces for wavefront manipulation necessarily results in limited bandwidth. Here, we propose the concept of dispersionless wavefront manipulation and report a theoretical, numerical and experimental work on the design of a reflective surface capable of controlling the acoustic wavefront arbitrarily without bandwidth limitation. Analytical analysis predicts the possibility to completely eliminate the frequency dependence with a specific gradient surface which can be implemented by designing a subwavelength corrugated surface. Experimental and numerical results, well consistent with the theoretical predictions, have validated the proposed scheme by demonstrating a distinct phenomenon of extraordinary acoustic reflection within an ultra-broad band. For acquiring a deeper insight into the underlying physics, a simple physical model is developed which helps to interpret this extraordinary phenomenon and predict the upper cutoff frequency precisely. Generations of planar focusing and non-diffractive beam have also been exemplified. With the dispersionless wave-steering capability and deep discrete resolution, our designed structure may open new avenue to fully steer classical waves and offer design possibilities for broadband optical/acoustical devices. PMID:26077772

  18. Superradiance of short electron pulses in regular and corrugated waveguides

    SciTech Connect

    Ginzburg, N.S.; Konoplev, I.V.; Sergeev, A.S.

    1995-12-31

    The report is devoted to theoretical and experimental study of superradiance of short electron pulses moving through waveguide systems. It is suggested that electrons oscillate or in undulator field (undulator SR) or in homogeneous magnetic field (cyclotron SR). We studied specific regimes of SR which may occur due to peculiarities of waveguide dispersion. Among them there are regimes of radiation near cut-off frequency as well as regimes of group synchronism. At the last operating regimes an electron bunch longitudinal velocity coincide with group velocity of e.m. wave. It is found the increasing of the SR instability grows rate and energy extraction efficiency in such regimes. It is also possible to observe the same enhancement using external feedback in periodically corrugated waveguide when Bragg resonance condition with forward propagated e.m. wave is fulfill. For experimental observation of cyclotron SR we intend to use compact subnanosecond accelerator RADAN 303B on the base of the high voltage generator with special subnansecond transformer. Accelerator generates short 0.3ns electron pulses with current about 1kA and particles energy 200keV. Design of magnetic confound system provide possibility to install an active locker to impose to electrons cyclotron rotation with pitch-factor about 1-1.5. According to numerical simulation at the mm and submm wavebands it is possible to achieve radiation pick power about 5-10MW with pulse duration less than 1ns.

  19. Corrugator activity confirms immediate negative affect in surprise.

    PubMed

    Topolinski, Sascha; Strack, Fritz

    2015-01-01

    The emotion of surprise entails a complex of immediate responses, such as cognitive interruption, attention allocation to, and more systematic processing of the surprising stimulus. All these processes serve the ultimate function to increase processing depth and thus cognitively master the surprising stimulus. The present account introduces phasic negative affect as the underlying mechanism responsible for this switch in operating mode. Surprising stimuli are schema-discrepant and thus entail cognitive disfluency, which elicits immediate negative affect. This affect in turn works like a phasic cognitive tuning switching the current processing mode from more automatic and heuristic to more systematic and reflective processing. Directly testing the initial elicitation of negative affect by surprising events, the present experiment presented high and low surprising neutral trivia statements to N = 28 participants while assessing their spontaneous facial expressions via facial electromyography. High compared to low surprising trivia elicited higher corrugator activity, indicative of negative affect and mental effort, while leaving zygomaticus (positive affect) and frontalis (cultural surprise expression) activity unaffected. Future research shall investigate the mediating role of negative affect in eliciting surprise-related outcomes.

  20. Corrugator activity confirms immediate negative affect in surprise

    PubMed Central

    Topolinski, Sascha; Strack, Fritz

    2015-01-01

    The emotion of surprise entails a complex of immediate responses, such as cognitive interruption, attention allocation to, and more systematic processing of the surprising stimulus. All these processes serve the ultimate function to increase processing depth and thus cognitively master the surprising stimulus. The present account introduces phasic negative affect as the underlying mechanism responsible for this switch in operating mode. Surprising stimuli are schema-discrepant and thus entail cognitive disfluency, which elicits immediate negative affect. This affect in turn works like a phasic cognitive tuning switching the current processing mode from more automatic and heuristic to more systematic and reflective processing. Directly testing the initial elicitation of negative affect by surprising events, the present experiment presented high and low surprising neutral trivia statements to N = 28 participants while assessing their spontaneous facial expressions via facial electromyography. High compared to low surprising trivia elicited higher corrugator activity, indicative of negative affect and mental effort, while leaving zygomaticus (positive affect) and frontalis (cultural surprise expression) activity unaffected. Future research shall investigate the mediating role of negative affect in eliciting surprise-related outcomes. PMID:25762956

  1. Dispersionless Manipulation of Reflected Acoustic Wavefront by Subwavelength Corrugated Surface.

    PubMed

    Zhu, Yi-Fan; Zou, Xin-Ye; Li, Rui-Qi; Jiang, Xue; Tu, Juan; Liang, Bin; Cheng, Jian-Chun

    2015-01-01

    Free controls of optic/acoustic waves for bending, focusing or steering the energy of wavefronts are highly desirable in many practical scenarios. However, the dispersive nature of the existing metamaterials/metasurfaces for wavefront manipulation necessarily results in limited bandwidth. Here, we propose the concept of dispersionless wavefront manipulation and report a theoretical, numerical and experimental work on the design of a reflective surface capable of controlling the acoustic wavefront arbitrarily without bandwidth limitation. Analytical analysis predicts the possibility to completely eliminate the frequency dependence with a specific gradient surface which can be implemented by designing a subwavelength corrugated surface. Experimental and numerical results, well consistent with the theoretical predictions, have validated the proposed scheme by demonstrating a distinct phenomenon of extraordinary acoustic reflection within an ultra-broad band. For acquiring a deeper insight into the underlying physics, a simple physical model is developed which helps to interpret this extraordinary phenomenon and predict the upper cutoff frequency precisely. Generations of planar focusing and non-diffractive beam have also been exemplified. With the dispersionless wave-steering capability and deep discrete resolution, our designed structure may open new avenue to fully steer classical waves and offer design possibilities for broadband optical/acoustical devices. PMID:26077772

  2. Dispersionless Manipulation of Reflected Acoustic Wavefront by Subwavelength Corrugated Surface

    NASA Astrophysics Data System (ADS)

    Zhu, Yi-Fan; Zou, Xin-Ye; Li, Rui-Qi; Jiang, Xue; Tu, Juan; Liang, Bin; Cheng, Jian-Chun

    2015-06-01

    Free controls of optic/acoustic waves for bending, focusing or steering the energy of wavefronts are highly desirable in many practical scenarios. However, the dispersive nature of the existing metamaterials/metasurfaces for wavefront manipulation necessarily results in limited bandwidth. Here, we propose the concept of dispersionless wavefront manipulation and report a theoretical, numerical and experimental work on the design of a reflective surface capable of controlling the acoustic wavefront arbitrarily without bandwidth limitation. Analytical analysis predicts the possibility to completely eliminate the frequency dependence with a specific gradient surface which can be implemented by designing a subwavelength corrugated surface. Experimental and numerical results, well consistent with the theoretical predictions, have validated the proposed scheme by demonstrating a distinct phenomenon of extraordinary acoustic reflection within an ultra-broad band. For acquiring a deeper insight into the underlying physics, a simple physical model is developed which helps to interpret this extraordinary phenomenon and predict the upper cutoff frequency precisely. Generations of planar focusing and non-diffractive beam have also been exemplified. With the dispersionless wave-steering capability and deep discrete resolution, our designed structure may open new avenue to fully steer classical waves and offer design possibilities for broadband optical/acoustical devices.

  3. Deployable Heat Pipe Radiator

    NASA Technical Reports Server (NTRS)

    Edelstein, F.

    1975-01-01

    A 1.2- by 1.8-m variable conductance heat pipe radiator was designed, built, and tested. The radiator has deployment capability and can passively control Freon-21 fluid loop temperatures under varying loads and environments. It consists of six grooved variable conductance heat pipes attached to a 0.032-in. aluminum panel. Heat is supplied to the radiator via a fluid header or a single-fluid flexible heat pipe header. The heat pipe header is an artery design that has a flexible section capable of bending up to 90 degrees. Radiator loads as high as 850 watts were successfully tested. Over a load variation of 200 watts, the outlet temperature of the Freon-21 fluid varied by 7 F. An alternate control system was also investigated which used a variable conductance heat pipe header attached to the heat pipe radiator panel.

  4. Dehumidifying Heat Pipe

    NASA Technical Reports Server (NTRS)

    Khattar, Mukesh K.

    1993-01-01

    U-shaped heat pipe partly dehumidifies air leaving air conditioner. Fits readily in air-handling unit of conditioner. Evaporator and condenser sections of heat pipe consist of finned tubes in comb pattern. Each tube sealed at one end and joined to manifold at other. Sections connected by single pipe carrying vapor to condenser manifold and liquid to evaporator manifold. Simple on/off or proportional valve used to control flow of working fluid. Valve actuated by temperature/humidity sensor.

  5. Abrasion resistant heat pipe

    DOEpatents

    Ernst, Donald M.

    1984-10-23

    A specially constructed heat pipe for use in fluidized bed combustors. Two distinct coatings are spray coated onto a heat pipe casing constructed of low thermal expansion metal, each coating serving a different purpose. The first coating forms aluminum oxide to prevent hydrogen permeation into the heat pipe casing, and the second coating contains stabilized zirconium oxide to provide abrasion resistance while not substantially affecting the heat transfer characteristics of the system.

  6. Abrasion resistant heat pipe

    DOEpatents

    Ernst, D.M.

    1984-10-23

    A specially constructed heat pipe is described for use in fluidized bed combustors. Two distinct coatings are spray coated onto a heat pipe casing constructed of low thermal expansion metal, each coating serving a different purpose. The first coating forms aluminum oxide to prevent hydrogen permeation into the heat pipe casing, and the second coating contains stabilized zirconium oxide to provide abrasion resistance while not substantially affecting the heat transfer characteristics of the system.

  7. External artery heat pipe

    NASA Technical Reports Server (NTRS)

    Gernert, Nelson J. (Inventor); Ernst, Donald M. (Inventor); Shaubach, Robert M. (Inventor)

    1989-01-01

    An improved heat pipe with an external artery. The longitudinal slot in the heat pipe wall which interconnects the heat pipe vapor space with the external artery is completely filled with sintered wick material and the wall of the external artery is also covered with sintered wick material. This added wick structure assures that the external artery will continue to feed liquid to the heat pipe evaporator even if a vapor bubble forms within and would otherwise block the liquid transport function of the external artery.

  8. Introduction to Heat Pipes

    NASA Technical Reports Server (NTRS)

    Ku, Jentung

    2015-01-01

    This is the presentation file for the short course Introduction to Heat Pipes, to be conducted at the 2015 Thermal Fluids and Analysis Workshop, August 3-7, 2015, Silver Spring, Maryland. NCTS 21070-15. Course Description: This course will present operating principles of the heat pipe with emphases on the underlying physical processes and requirements of pressure and energy balance. Performance characterizations and design considerations of the heat pipe will be highlighted. Guidelines for thermal engineers in the selection of heat pipes as part of the spacecraft thermal control system, testing methodology, and analytical modeling will also be discussed.

  9. Heat pipe investigations

    NASA Technical Reports Server (NTRS)

    Marshburn, J. P.

    1972-01-01

    The OAO-C spacecraft has three circular heat pipes, each of a different internal design, located in the space between the spacecraft structural tube and the experiment tube, which are designed to isothermalize the structure. Two of the pipes are used to transport high heat loads, and the third is for low heat loads. The test problems deal with the charging of the pipes, modifications, the mobile tilt table, the position indicator, and the heat input mechanisms. The final results showed that the techniques used were adequate for thermal-vacuum testing of heat pipes.

  10. Internal pipe attachment mechanism

    DOEpatents

    Bast, R.M.; Chesnut, D.A.; Henning, C.D.; Lennon, J.P.; Pastrnak, J.W.; Smith, J.A.

    1994-12-13

    An attachment mechanism is described for repairing or extending fluid carrying pipes, casings, conduits, etc. utilizing one-way motion of spring tempered fingers to provide a mechanical connection between the attachment mechanism and the pipe. The spring tempered fingers flex to permit insertion into a pipe to a desired insertion depth. The mechanical connection is accomplished by reversing the insertion motion and the mechanical leverage in the fingers forces them outwardly against the inner wall of the pipe. A seal is generated by crushing a sealing assembly by the action of setting the mechanical connection. 6 figures.

  11. Internal pipe attachment mechanism

    DOEpatents

    Bast, Richard M.; Chesnut, Dwayne A.; Henning, Carl D.; Lennon, Joseph P.; Pastrnak, John W.; Smith, Joseph A.

    1994-01-01

    An attachment mechanism for repairing or extending fluid carrying pipes, casings, conduits, etc. utilizing one-way motion of spring tempered fingers to provide a mechanical connection between the attachment mechanism and the pipe. The spring tempered fingers flex to permit insertion into a pipe to a desired insertion depth. The mechanical connection is accomplished by reversing the insertion motion and the mechanical leverage in the fingers forces them outwardly against the inner wall of the pipe. A seal is generated by crushing a sealing assembly by the action of setting the mechanical connection.

  12. Heat Pipe Materials Compatibility

    NASA Technical Reports Server (NTRS)

    Eninger, J. E.; Fleischman, G. L.; Luedke, E. E.

    1976-01-01

    An experimental program to evaluate noncondensable gas generation in ammonia heat pipes was completed. A total of 37 heat pipes made of aluminum, stainless steel and combinations of these materials were processed by various techniques, operated at different temperatures and tested at low temperature to quantitatively determine gas generation rates. In order of increasing stability are aluminum/stainless combination, all aluminum and all stainless heat pipes. One interesting result is the identification of intentionally introduced water in the ammonia during a reflux step as a means of surface passivation to reduce gas generation in stainless-steel/aluminum heat pipes.

  13. Pipe crawler apparatus

    DOEpatents

    Hovis, Gregory L.; Erickson, Scott A.; Blackmon, Bruce L.

    2002-01-01

    A pipe crawler apparatus particularly useful for 3-inch and 4-inch diameter pipes is provided. The pipe crawler apparatus uses a gripping apparatus in which a free end of a piston rod is modified with a bearing retaining groove. Bearings, placed within the groove, are directed against a camming surface of three respective pivoting support members. The non-pivoting ends of the support members carry a foot-like gripping member that, upon pivoting of the support member, engages the interior wall of the pipe.

  14. Heat Pipe Planets

    NASA Technical Reports Server (NTRS)

    Moore, William B.; Simon, Justin I.; Webb, A. Alexander G.

    2014-01-01

    When volcanism dominates heat transport, a terrestrial body enters a heat-pipe mode, in which hot magma moves through the lithosphere in narrow channels. Even at high heat flow, a heat-pipe planet develops a thick, cold, downwards-advecting lithosphere dominated by (ultra-)mafic flows and contractional deformation at the surface. Heat-pipes are an important feature of terrestrial planets at high heat flow, as illustrated by Io. Evidence for their operation early in Earth's history suggests that all terrestrial bodies should experience an episode of heat-pipe cooling early in their histories.

  15. Linear analysis of a backward wave oscillator with triangular corrugated slow wave structure

    NASA Astrophysics Data System (ADS)

    Saber, Md. Ghulam; Sagor, Rakibul Hasan; Amin, Md. Ruhul

    2016-05-01

    In this work, a backward wave oscillator (BWO) with triangularly corrugated periodic metallic slow wave structure (TrCSWS) driven by an infinitely thin annular electron beam is studied using linear theory. The electron beam is assumed to be guided by a strong magnetic field. The triangular axial profile of the SWS is approximated by a Fourier series in order to apply the linear Rayleigh-Fourier (R-F) theory that has long been used in the theoretical analysis of BWOs with sinusoidally corrugated SWS (SCSWS). The dispersion equation for various beam parameters has been solved and the temporal growth rate (TGR) of the electromagnetic wave for the fundamental TM_{01} mode is calculated numerically. The TGR values for different beam parameters have been compared with those of the BWO with SCSWS, semi-circularly corrugated SWS (SCCSWS) and trapezoidally corrugated SWS (TCSWS). In order to compare the TGR values, the amplitude of corrugation of the TrCSWS is varied so that its dispersion curve of TM_{01} mode almost coincides with that of the SCSWS and TCSWS. The study reveals that the performance (in terms of TGR) of the proposed BWO with TrCSWS is comparable to that of other BWOs with SCSWS and TCSWS for the same set of beam parameters and it provides significantly better performance than SCCSWS. So, the proposed TrCSWS that can easily be constructed may replace SCSWS, SCCSWS or TCSWS as their viable alternative.

  16. Heat pipe methanator

    DOEpatents

    Ranken, William A.; Kemme, Joseph E.

    1976-07-27

    A heat pipe methanator for converting coal gas to methane. Gravity return heat pipes are employed to remove the heat of reaction from the methanation promoting catalyst, transmitting a portion of this heat to an incoming gas pre-heat section and delivering the remainder to a steam generating heat exchanger.

  17. These Pipes Are "Happening"

    ERIC Educational Resources Information Center

    Skophammer, Karen

    2010-01-01

    The author is blessed with having the water pipes for the school system in her office. In this article, the author describes how the breaking of the pipes had led to a very worthwhile art experience for her students. They practiced contour and shaded drawing techniques, reviewed patterns and color theory, and used their reasoning skills--all while…

  18. Unstable heat pipes

    SciTech Connect

    McGuinness, M.J.; Pruess, K.

    1987-10-01

    Heat pipes are an important feature of models of vapor-dominated geothermal reservoirs. Numerical experiments reveal that a vapor-dominated heat pipe is unstable if pressure is controlled at shallow levels. This instability is discussed in physical terms, and some implications for geothermal reservoirs are considered. 9 refs., 10 figs.

  19. Extendable pipe crawler

    DOEpatents

    Hapstack, Mark

    1991-01-01

    A pipe crawler having a front leg assembly and a back leg assembly connected together by two air cylinders, each leg assembly having four extendable legs and a pair of actuators for sliding the extendable legs radially outward to increase the range of the legs when the pipe crawler enters a section of a pipe having a larger diameter. The crawler crawls by "inchworm"-like motion, the front leg assembly and back leg assembly alternately engaging and disengaging the wall of the pipe to hold the pipe crawler as the air cylinders alternately advance the front leg assembly and bring up the rear leg assembly. The pair of actuators of each leg assembly are parallel, adjacent and opposing acting so that each slides two adjacent extendable legs radially outward.

  20. Extendable pipe crawler

    DOEpatents

    Hapstack, M.

    1991-05-28

    A pipe crawler is described having a front leg assembly and a back leg assembly connected together by two air cylinders, each leg assembly having four extendable legs and a pair of actuators for sliding the extendable legs radially outward to increase the range of the legs when the pipe crawler enters a section of a pipe having a larger diameter. The crawler crawls by inchworm'-like motion, the front leg assembly and back leg assembly alternately engaging and disengaging the wall of the pipe to hold the pipe crawler as the air cylinders alternately advance the front leg assembly and bring up the rear leg assembly. The pair of actuators of each leg assembly are parallel, adjacent and opposing acting so that each slides two adjacent extendable legs radially outward. 5 figures.

  1. Reduction in Young`s modulus of aluminum foams due to cell wall curvature and corrugation

    SciTech Connect

    Sanders, W.; Gibson, L.J.

    1998-12-31

    Measurements of the Young`s modulus and compressive strength of several closed-cell aluminum foams indicate that they are lower than expected from models for foam behavior. Microstructural characterization has revealed that there are a number of defects in the cell structure which may contribute to the reduction in mechanical properties. These include: cell wall curvature, cell wall corrugations, density variations and non-equiaxed cell shape. Finite element analysis of a closed-cell tetrakaidecahedral unit cell with idealized curved or corrugated cell walls indicates that these two types of defects can reduce the Young`s modulus and compressive strength by up to 70%. In this paper the authors report the results of measurements of the curvature of the cell walls and of the amplitude and frequency of corrugations in the cell walls and use simple bounds to estimate the reduction in modulus that they are responsible for.

  2. Trapping of surface plasmon wave through gradient corrugated strip with underlayer ground and manipulating its propagation

    NASA Astrophysics Data System (ADS)

    Zhang, Wenjuan; Zhu, Guiqiang; Sun, Liguo; Lin, Fujiang

    2015-01-01

    Corrugated metal surface with underlayer metal as ground is designed as spoof surface plasmons polaritons (SSPPs) structure in microwave frequencies. Efficient conversion from guided wave to SSPP is required for energy feeding into and signal extracting from such plasmonic structure. In this paper, first a high efficient transition design is presented by using gradient corrugated strip with underlayer metal as ground and by using the impedance matching theory. The SSPP wave is highly confined within the teeth part of the corrugated surface. By using this characteristic, then the simple wire-based metamaterial is added below the strip to manipulate the SSPP wave within the propagating band. Two aforementioned devices are designed and fabricated. The simulated and measured results on the scattering coefficients demonstrate the excellent conversion and excellent manipulating of SSPP transmitting. Such results have very important value to develop advanced plasmonic integrated circuits in the microwave frequencies.

  3. Impact-damaged graphite-thermoplastic trapezoidal-corrugation sandwich and semi-sandwich panels

    NASA Technical Reports Server (NTRS)

    Jegley, D.

    1993-01-01

    The results of a study of the effects of impact damage on compression-loaded trapezoidal-corrugation sandwich and semi-sandwich graphite-thermoplastic panels are presented. Sandwich panels with two identical face sheets and a trapezoidal corrugated core between them, and semi-sandwich panels with a corrugation attached to a single skin are considered in this study. Panels were designed, fabricated and tested. The panels were made using the manufacturing process of thermoforming, a less-commonly used technique for fabricating composite parts. Experimental results for unimpacted control panels and panels subjected to impact damage prior to loading are presented. Little work can be found in the literature about these configurations of thermoformed panels.

  4. 77 FR 67400 - RG Steel Wheeling, LLC, a Division of RG Steel, LLC, Doing Business as Wheeling Corrugating...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-09

    ... Employment and Training Administration RG Steel Wheeling, LLC, a Division of RG Steel, LLC, Doing Business as Wheeling Corrugating Company, Including Workers Whose Wages Were Reported Through Severstal Wheeling, Beech... Wheeling Corrugating Company, Beech Bottom, West Virginia. The Department's notice of determination...

  5. Corrugated velocity pattern in spiral galaxies: NGC 278, NGC 1058, NGC 2500 and UGC 3574

    NASA Astrophysics Data System (ADS)

    Sánchez Gil, M. C.; Alfaro, E. J.; Pérez, E.

    2011-11-01

    We report the detection in Hα emission of a radial corrugation pattern in the vertical velocity field of a sample of nearby face-on, spiral galaxies. We obtain long-slit spectra with the double arm ISIS spectrograph, attached to the 4.2 m William Herschel Telescope. The existence of corrugations has been already reported, e.g. Alfaro et al. (2001), Matthews & Uson (2008). Corrugations are closely link, as cause/effect, to the large scale star formation processes: density waves, tidal interactions, galactic bores, collisions of high velocity clouds with disk, etc. Which mechanism is the origin of disk corrugations is still an open problem. In this work not only the existence of radial and azimuthal corrugations are clearly observed, we report a first systematic study on the velocity corrugations in a sample of nearly face-on spiral galaxies. NGC 278 and NGC 1058 show a similar behavior to NGC 5427 (Alfaro et al. 2001), with a clear displacement between the velocities and emission line peaks. Where the approaching velocity peaks occur in the convex border of the arms, and the receding maxima are located behind the Hα emission maxima, in the concave side. This kinematical behavior is similar to the one expected in a galactic bore generated by the interaction of a spiral density wave with a thick gaseous disk. NGC 2500 and UGC 3574 do not show so clear this last relation between the velocity and emission line peaks, a possible cause should a fainter and discontinuous Hα emission. Oddly, these two pairs of galaxies also differ between them in their ionization mechanism features obtained from diagnostic diagrams.

  6. Near field of corrugated horns and its influence on dual reflector antenna radiation performance

    NASA Astrophysics Data System (ADS)

    Hombach, V.; Kuehn, E.

    1985-05-01

    The existing procedures for calculating the near field of the corrugated horns of dual reflector antennas are briefly reviewed, and their disadvantages are pointed out. A new approach to calculating the near field of circular corrugated feed horns is then discussed with specific reference to a Ku-band offset Gregorian antenna developed for the German Telecommunication Satellite DFS scheduled for launch in 1987. The approach, which is based on a physical-optics solution, is shown to provide an accurate description of the actual radiation characteristics. The effect of the near field on the gain, side-lobe level, and cross-polar performance of the antenna is discussed.

  7. Graphene-assisted near-field radiative heat transfer between corrugated polar materials

    SciTech Connect

    Liu, X. L.; Zhang, Z. M.

    2014-06-23

    Graphene has attracted great attention in nanoelectronics, optics, and energy harvesting. Here, the near-field radiative heat transfer between graphene-covered corrugated silica is investigated based on the exact scattering theory. It is found that graphene can improve the radiative heat flux between silica gratings by more than one order of magnitude and alleviate the performance sensitivity to lateral shift. The underlying mechanism is mainly attributed to the improved photon tunneling of modes away from phonon resonances. Besides, coating with graphene leads to nonlocal radiative transfer that breaks Derjaguin's proximity approximation and enables corrugated silica to outperform bulk silica in near-field radiation.

  8. Elastic constants for superplastically formed/diffusion-bonded corrugated sandwich core

    NASA Technical Reports Server (NTRS)

    Ko, W. L.

    1980-01-01

    Formulas and associated graphs for evaluating the effective elastic constants for a superplastically formed/diffusion bonded (SPF/DB) corrugated sandwich core, are presented. A comparison of structural stiffnesses of the sandwich core and a honeycomb core under conditions of equal sandwich core density was made. The stiffness in the thickness direction of the optimum SPF/DB corrugated core (that is, triangular truss core) is lower than that of the honeycomb core, and that the former has higher transverse shear stiffness than the latter.

  9. Structural efficiency studies of corrugated compression panels with curved caps and beaded webs

    NASA Technical Reports Server (NTRS)

    Davis, R. C.; Mills, C. T.; Prabhakaran, R.; Jackson, L. R.

    1984-01-01

    Curved cross-sectional elements are employed in structural concepts for minimum-mass compression panels. Corrugated panel concepts with curved caps and beaded webs are optimized by using a nonlinear mathematical programming procedure and a rigorous buckling analysis. These panel geometries are shown to have superior structural efficiencies compared with known concepts published in the literature. Fabrication of these efficient corrugation concepts became possible by advances made in the art of superplastically forming of metals. Results of the mass optimization studies of the concepts are presented as structural efficiency charts for axial compression.

  10. Tests of Large Airfoils in the Propeller Research Tunnel, Including Two with Corrugated Surfaces

    NASA Technical Reports Server (NTRS)

    Wood, Donald H

    1930-01-01

    This report gives the results of the tests of seven 2 by 12 foot airfoils (Clark Y, smooth and corrugated, Gottingen 398, N.A.C.A. M-6, and N.A.C.A. 84). The tests were made in the propeller research tunnel of the National Advisory Committee for Aeronautics at Reynolds numbers up to 2,000,000. The Clark Y airfoil was tested with three degrees of surface smoothness. Corrugating the surface causes a flattening of the lift curve at the burble point and an increase in drag at small flying angles.

  11. Experimental investigation of heat transfer and effectiveness in corrugated plate heat exchangers having different chevron angles

    NASA Astrophysics Data System (ADS)

    Kılıç, Bayram; İpek, Osman

    2016-06-01

    In this study, heat transfer rate and effectiveness of corrugated plate heat exchangers having different chevron angles were investigated experimentally. Chevron angles of plate heat exchangers are β = 30° and β = 60°. For this purpose, experimentally heating system used plate heat exchanger was designed and constructed. Thermodynamic analysis of corrugated plate heat exchangers having different chevron angles were carried out. The heat transfer rate and effectiveness values are calculated. The experimental results are shown that heat transfer rate and effectiveness values for β = 60° is higher than that of the other. Obtained experimental results were graphically presented.

  12. Flexible ultrasonic pipe inspection apparatus

    DOEpatents

    Jenkins, C.F.; Howard, B.D.

    1994-01-01

    Pipe crawlers, pipe inspection {open_quotes}rabbits{close_quotes} and similar vehicles are widely used for inspecting the interior surfaces of piping systems, storage tanks and process vessels for damaged or flawed structural features. This paper describes the design of a flexible, modular ultrasonic pipe inspection apparatus.

  13. Experimenting with a "Pipe" Whistle

    ERIC Educational Resources Information Center

    Stafford, Olga

    2012-01-01

    A simple pipe whistle can be made using pieces of PVC pipe. The whistle can be used to measure the resonant frequencies of open or closed pipes. A slightly modified version of the device can be used to also investigate the interesting dependence of the sound frequencies produced on the orifice-to-edge distance. The pipe whistle described here…

  14. Determination of the geometric corrugation of graphene on SiC(0001) by grazing incidence fast atom diffraction

    SciTech Connect

    Zugarramurdi, A.; Debiossac, M.; Lunca-Popa, P.; Mayne, A. J.; Borisov, A. G.; Mu, Z.; Roncin, P.; Khemliche, H.; Momeni, A.

    2015-03-09

    We present a grazing incidence fast atom diffraction (GIFAD) study of monolayer graphene on 6H-SiC(0001). This system shows a Moiré-like 13 × 13 superlattice above the reconstructed carbon buffer layer. The averaging property of GIFAD results in electronic and geometric corrugations that are well decoupled; the graphene honeycomb corrugation is only observed with the incident beam parallel to the zigzag direction while the geometric corrugation arising from the superlattice is revealed along the armchair direction. Full-quantum calculations of the diffraction patterns show the very high GIFAD sensitivity to the amplitude of the surface corrugation. The best agreement between the calculated and measured diffraction intensities yields a corrugation height of 0.27 ± 0.03 Å.

  15. An electrohydrodynamic heat pipe.

    NASA Technical Reports Server (NTRS)

    Jones, T. B.

    1972-01-01

    A heat pipe of new design, using an electrode structure to orient and guide the dielectric liquid phase flow, is proposed. Analysis indicates that the operation of the electrohydrodynamic heat pipe is in direct analogy to capillary devices, with the polarization force acting in place of capillarity. Advantages of these new heat pipes include greatly reduced liquid friction, electrohydrodynamically enhanced evaporation and condensation heat transfer, and a possible voltage-controlled on/off feature. Preliminary calculations indicate that relatively high performance devices are possible.

  16. Electrohydrodynamic heat pipes.

    NASA Technical Reports Server (NTRS)

    Jones, T. B.

    1973-01-01

    An electrohydrodynamic heat pipe of radical design is proposed which substitutes polarization electrohydrodynamic force effects for capillarity in collecting, guiding, and pumping a condensate liquid phase. The discussed device is restricted to the use of dielectric liquids as working fluids. Because of the relatively poor thermal transport properties of these liquids, capillary heat pipes using these liquids have not been high performance devices. The employment of the electrohydrodynamic concept should enhance this performance and help fill the performance gap that exists in the temperature range from 250 F to 750 F for 'conventional' capillary heat pipes.

  17. Gas pipe explorer robot

    NASA Technical Reports Server (NTRS)

    Wilcox, Brian (Inventor)

    2004-01-01

    A gas pipe explorer formed of a plurality of connecting elements, and an articulation element between the connected elements. The connected elements include drive capabilities, and the articulation element allows the connected elements to traverse gas pipes of arbitrary shapes and sizes. A sensor may sends the characteristics of the gas pipe, and the communication element may send back those sends characteristics. The communication can be wired, over a tether connecting the device to a remote end. Alternatively, the connection can be wireless, driven by either a generator or a battery.

  18. AutoPIPE Extract Program

    SciTech Connect

    Cline, Barbara E.

    1993-07-02

    The AutoPIPE Extract Program (APEX) provides an interface between CADAM (Computer Aided Design and Manufacturing) Release 21 drafting software and the AutoPIPE, Version 4.4, piping analysis program. APEX produces the AutoPIPE batch input file that corresponds to the piping shown in a CADAM model. The card image file contains header cards, material cards, and pipe cross section cards as well as tee, bend, valve, and flange cards. Node numbers are automatically generated. APEX processes straight pipe, branch lines and ring geometries.

  19. AutoPIPE Extract Program

    1993-07-02

    The AutoPIPE Extract Program (APEX) provides an interface between CADAM (Computer Aided Design and Manufacturing) Release 21 drafting software and the AutoPIPE, Version 4.4, piping analysis program. APEX produces the AutoPIPE batch input file that corresponds to the piping shown in a CADAM model. The card image file contains header cards, material cards, and pipe cross section cards as well as tee, bend, valve, and flange cards. Node numbers are automatically generated. APEX processes straightmore » pipe, branch lines and ring geometries.« less

  20. Improved Thin, Flexible Heat Pipes

    NASA Technical Reports Server (NTRS)

    Rosenfeld, John H.; Gernert, Nelson J.; Sarraf, David B.; Wollen, Peter J.; Surina, Frank C.; Fale, John E.

    2004-01-01

    Flexible heat pipes of an improved type are fabricated as layers of different materials laminated together into vacuum- tight sheets or tapes. In comparison with prior flexible heat pipes, these flexible heat pipes are less susceptible to leakage. Other advantages of these flexible heat pipes, relative to prior flexible heat pipes, include high reliability and greater ease and lower cost of fabrication. Because these heat pipes are very thin, they are highly flexible. When coated on outside surfaces with adhesives, these flexible heat pipes can be applied, like common adhesive tapes, to the surfaces of heat sinks and objects to be cooled, even if those surfaces are curved.

  1. Heat pipe manufacturing study

    NASA Technical Reports Server (NTRS)

    Edelstein, F.

    1974-01-01

    Heat pipe manufacturing methods are examined with the goal of establishing cost effective procedures that will ultimately result in cheaper more reliable heat pipes. Those methods which are commonly used by all heat pipe manufacturers have been considered, including: (1) envelope and wick cleaning, (2) end closure and welding, (3) mechanical verification, (4) evacuation and charging, (5) working fluid purity, and (6) charge tube pinch off. The study is limited to moderate temperature aluminum and stainless steel heat pipes with ammonia, Freon-21 and methanol working fluids. Review and evaluation of available manufacturers techniques and procedures together with the results of specific manufacturing oriented tests have yielded a set of recommended cost-effective specifications which can be used by all manufacturers.

  2. The pipes of pan.

    PubMed

    Chalif, David J

    2004-12-01

    The pipes of pan is the crowning achievement of Pablo Picasso's neoclassical period of the 1920s. This monumental canvas depicts a mythological Mediterranean scene in which two sculpted classical giants stare out, seemingly across the centuries, toward a distant and lost Arcadia. Picasso was influenced by Greco-Roman art during his travels in Italy, and his neoclassical works typically portray massive, immobile, and pensive figures. Pan and his pipes are taken directly from Greek mythological lore by Picasso and placed directly into 20th century art. He frequently turned to various mythological figures throughout his metamorphosing periods. The Pipes of Pan was also influenced by the painter's infatuation with the beautiful American expatriate Sara Murphy, and the finished masterpiece represents a revision of a previously conceived neoclassical work. The Pipes of Pan now hangs in the Musee Picasso in Paris.

  3. Ceramic heat pipe development

    NASA Astrophysics Data System (ADS)

    Merrigan, M.

    1980-09-01

    Ceramic materials used in conventional brickwork heat exchanger configurations increase allowable temperatures; however, joint leakage problems limit use of these designs. Ceramic tube heat exchanger designs reduce these problems but still require sliding joints and compliant tube end seals. Ceramic heat pipe based recuperator designs eliminate the sealing problems that limited the high temperature heat recovery installations. Heat pipe recuperators offer high corrosion and abrasion resistance, high temperature capability, reduced leakage, element redundancy, and simplified replacement and cleaning. The development of ceramic heat pipe recuperator elements involves the selection and test of materials and fabrication techniques having production potential, evaluation of technology in subscale tests, design and test of components for full scale recuperator applications, and demonstration of heat pipes in subscale and full scale recuperator installation.

  4. Miniature pipe crawler tractor

    SciTech Connect

    McKay, M.D.; Anderson, M.O.; Ferrante, T.A.; Willis, W.D.

    2000-03-14

    A pipe crawler tractor may comprise a half tractor assembly having a first base drive wheel, a second base drive wheel, and a top drive wheel. The drive wheels are mounted in spaced-apart relation so that the top drive wheel is positioned between the first and second base drive wheels. The mounting arrangement is also such that the first and second base drive wheels contact the inside surface of the pipe at respective first and second positions and so that the top drive wheel contacts the inside surface of the pipe at a third position, the third position being substantially diametrically opposed to the first and second positions. A control system connected to the half tractor assembly controls the rotation of the first base wheel, the second base wheel, and the top drive wheel to move the half tractor assembly within the pipe.

  5. Heat Pipe Systems

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The heat pipe was developed to alternately cool and heat without using energy or any moving parts. It enables non-rotating spacecraft to maintain a constant temperature when the surface exposed to the Sun is excessively hot and the non Sun-facing side is very cold. Several organizations, such as Tropic-Kool Engineering Corporation, joined NASA in a subsequent program to refine and commercialize the technology. Heat pipes have been installed in fast food restaurants in areas where humid conditions cause materials to deteriorate quickly. Moisture removal was increased by 30 percent in a Clearwater, FL Burger King after heat pipes were installed. Relative humidity and power consumption were also reduced significantly. Similar results were recorded by Taco Bell, which now specifies heat pipe systems in new restaurants in the Southeast.

  6. Miniature pipe crawler tractor

    DOEpatents

    McKay, Mark D.; Anderson, Matthew O.; Ferrante, Todd A.; Willis, W. David

    2000-01-01

    A pipe crawler tractor may comprise a half tractor assembly having a first base drive wheel, a second base drive wheel, and a top drive wheel. The drive wheels are mounted in spaced-apart relation so that the top drive wheel is positioned between the first and second base drive wheels. The mounting arrangement is also such that the first and second base drive wheels contact the inside surface of the pipe at respective first and second positions and so that the top drive wheel contacts the inside surface of the pipe at a third position, the third position being substantially diametrically opposed to the first and second positions. A control system connected to the half tractor assembly controls the rotation of the first base wheel, the second base wheel, and the top drive wheel to move the half tractor assembly within the pipe.

  7. Freezable heat pipe

    DOEpatents

    Ernst, Donald M.; Sanzi, James L.

    1981-02-03

    A heat pipe whose fluid can be repeatedly frozen and thawed without damage to the casing. An additional part is added to a conventional heat pipe. This addition is a simple porous structure, such as a cylinder, self-supporting and free standing, which is dimensioned with its diameter not spanning the inside transverse dimension of the casing, and with its length surpassing the depth of maximum liquid.

  8. Silicon Heat Pipe Array

    NASA Technical Reports Server (NTRS)

    Yee, Karl Y.; Ganapathi, Gani B.; Sunada, Eric T.; Bae, Youngsam; Miller, Jennifer R.; Beinsford, Daniel F.

    2013-01-01

    Improved methods of heat dissipation are required for modern, high-power density electronic systems. As increased functionality is progressively compacted into decreasing volumes, this need will be exacerbated. High-performance chip power is predicted to increase monotonically and rapidly with time. Systems utilizing these chips are currently reliant upon decades of old cooling technology. Heat pipes offer a solution to this problem. Heat pipes are passive, self-contained, two-phase heat dissipation devices. Heat conducted into the device through a wick structure converts the working fluid into a vapor, which then releases the heat via condensation after being transported away from the heat source. Heat pipes have high thermal conductivities, are inexpensive, and have been utilized in previous space missions. However, the cylindrical geometry of commercial heat pipes is a poor fit to the planar geometries of microelectronic assemblies, the copper that commercial heat pipes are typically constructed of is a poor CTE (coefficient of thermal expansion) match to the semiconductor die utilized in these assemblies, and the functionality and reliability of heat pipes in general is strongly dependent on the orientation of the assembly with respect to the gravity vector. What is needed is a planar, semiconductor-based heat pipe array that can be used for cooling of generic MCM (multichip module) assemblies that can also function in all orientations. Such a structure would not only have applications in the cooling of space electronics, but would have commercial applications as well (e.g. cooling of microprocessors and high-power laser diodes). This technology is an improvement over existing heat pipe designs due to the finer porosity of the wick, which enhances capillary pumping pressure, resulting in greater effective thermal conductivity and performance in any orientation with respect to the gravity vector. In addition, it is constructed of silicon, and thus is better

  9. Heat pipe dynamic behavior

    NASA Technical Reports Server (NTRS)

    Issacci, F.; Roche, G. L.; Klein, D. B.; Catton, I.

    1988-01-01

    The vapor flow in a heat pipe was mathematically modeled and the equations governing the transient behavior of the core were solved numerically. The modeled vapor flow is transient, axisymmetric (or two-dimensional) compressible viscous flow in a closed chamber. The two methods of solution are described. The more promising method failed (a mixed Galerkin finite difference method) whereas a more common finite difference method was successful. Preliminary results are presented showing that multi-dimensional flows need to be treated. A model of the liquid phase of a high temperature heat pipe was developed. The model is intended to be coupled to a vapor phase model for the complete solution of the heat pipe problem. The mathematical equations are formulated consistent with physical processes while allowing a computationally efficient solution. The model simulates time dependent characteristics of concern to the liquid phase including input phase change, output heat fluxes, liquid temperatures, container temperatures, liquid velocities, and liquid pressure. Preliminary results were obtained for two heat pipe startup cases. The heat pipe studied used lithium as the working fluid and an annular wick configuration. Recommendations for implementation based on the results obtained are presented. Experimental studies were initiated using a rectangular heat pipe. Both twin beam laser holography and laser Doppler anemometry were investigated. Preliminary experiments were completed and results are reported.

  10. Conductor load bearing roller for a gas-insulated transmission line having a corrugated outer conductor

    DOEpatents

    Fischer, William H.; Yoon, Kue H.

    1984-04-10

    A gas-insulated transmission line includes a corrugated outer conductor, an inner conductor disposed within and insulated from the outer conductor by means of support insulators and an insulating gas, and a transport device for supporting and permitting movement of the inner conductor/insulating support assembly axially along the corrugated outer conductor without radial displacement. The transport device includes two movable contacts, such as skids or rollers, supported on a common pivot lever, the pivot lever being rotatably disposed about a pivot lever axis, which pivot lever axis is in turn disposed on the periphery of a support insulator or particle trap if one is used. The movable contacts are separated axially a distance equal to the axial distance between the peaks and valleys of the corrugations of the outer conductor and separated radially a distance equal to the radial distance between the peaks and valleys of the corrugations of the outer conductor. The transport device has the pivot lever axis disposed perpendicular to the direction of travel of the inner conductor/insulating support assembly.

  11. Corrugated velocity patterns in the spiral galaxies NGC 278, NGC 1058, NGC 2500 & UGC 3574

    NASA Astrophysics Data System (ADS)

    Sánchez Gil, M. C.; Alfaro, E. J.; Pérez, E.

    2013-05-01

    In this work we address the study of the detection in Ha of a radial corrugation in the vertical velocity field in a sample of four nearly face-on, spiral galaxies. The geometry of the problem is a main criterion in the selection of the sample as well as of the azimuthal angle of the slits. These spatial corrugations must be equally associated with wavy vertical motions in the galactic plane with a strong large-scale consistency. Evidence of these kinematic waves were first detected in the analysis of the rotation curves of spiral galaxies (e.g. te{1963ApJ...137..363D,1965BOTT....4....8P}), but it was not until 2001 that te{2001ApJ...550..253A} analyzed in more detail the velocity corrugations in NGC 5427 and a possible physical mechanism for their origin. The aim of this study is to analyze the corrugated velocity pattern in terms of the star formation processes. We describe the geometry of the problem and establish its fundamental relationships.

  12. Method for producing ultrafine-grained materials using repetitive corrugation and straightening

    DOEpatents

    Zhu, Yuntian T.; Lowe, Terry C.; Jiang, Honggang; Huang, Jianyu

    2001-01-01

    A method of refining the grain structure and improving the hardness and strength properties of a metal or metal alloy workpiece is disclosed. The workpiece is subjected to forces that corrugate and then straighten the workpiece. These steps are repeated until an ultrafine-grained product having improved hardness and strength is produced.

  13. Heat Pipe Integrated Microsystems

    SciTech Connect

    Gass, K.; Robertson, P.J.; Shul, R.; Tigges, C.

    1999-03-30

    The trend in commercial electronics packaging to deliver ever smaller component packaging has enabled the development of new highly integrated modules meeting the demands of the next generation nano satellites. At under ten kilograms, these nano satellites will require both a greater density electronics and a melding of satellite structure and function. Better techniques must be developed to remove the subsequent heat generated by the active components required to-meet future computing requirements. Integration of commercially available electronics must be achieved without the increased costs normally associated with current generation multi chip modules. In this paper we present a method of component integration that uses silicon heat pipe technology and advanced flexible laminate circuit board technology to achieve thermal control and satellite structure. The' electronics/heat pipe stack then becomes an integral component of the spacecraft structure. Thermal management on satellites has always been a problem. The shrinking size of electronics and voltage requirements and the accompanying reduction in power dissipation has helped the situation somewhat. Nevertheless, the demands for increased onboard processing power have resulted in an ever increasing power density within the satellite body. With the introduction of nano satellites, small satellites under ten kilograms and under 1000 cubic inches, the area available on which to place hot components for proper heat dissipation has dwindled dramatically. The resulting satellite has become nearly a solid mass of electronics with nowhere to dissipate heat to space. The silicon heat pipe is attached to an aluminum frame using a thermally conductive epoxy or solder preform. The frame serves three purposes. First, the aluminum frame provides a heat conduction path from the edge of the heat pipe to radiators on the surface of the satellite. Secondly, it serves as an attachment point for extended structures attached to

  14. Effects of corrugation shape on frequency band-gaps for longitudinal wave motion in a periodic elastic layer.

    PubMed

    Sorokin, Vladislav S

    2016-04-01

    The paper concerns determining frequency band-gaps for longitudinal wave motion in a periodic waveguide. The waveguide may be considered either as an elastic layer with variable thickness or as a rod with variable cross section. As a result, widths and locations of all frequency band-gaps are determined by means of the method of varying amplitudes. For the general symmetric corrugation shape, the width of each odd band-gap is controlled only by one harmonic in the corrugation series with its number being equal to the number of the band-gap. Widths of even band-gaps, however, are influenced by all the harmonics involved in the corrugation series, so that the lower frequency band-gaps can emerge. These are band-gaps located below the frequency corresponding to the lowest harmonic in the corrugation series. For the general non-symmetric corrugation shape, the mth band-gap is controlled only by one, the mth, harmonic in the corrugation series. The revealed insights into the mechanism of band-gap formation can be used to predict locations and widths of all frequency band-gaps featured by any corrugation shape. These insights are general and can be valid also for other types of wave motion in periodic structures, e.g., transverse or torsional vibration.

  15. Effects of corrugation shape on frequency band-gaps for longitudinal wave motion in a periodic elastic layer.

    PubMed

    Sorokin, Vladislav S

    2016-04-01

    The paper concerns determining frequency band-gaps for longitudinal wave motion in a periodic waveguide. The waveguide may be considered either as an elastic layer with variable thickness or as a rod with variable cross section. As a result, widths and locations of all frequency band-gaps are determined by means of the method of varying amplitudes. For the general symmetric corrugation shape, the width of each odd band-gap is controlled only by one harmonic in the corrugation series with its number being equal to the number of the band-gap. Widths of even band-gaps, however, are influenced by all the harmonics involved in the corrugation series, so that the lower frequency band-gaps can emerge. These are band-gaps located below the frequency corresponding to the lowest harmonic in the corrugation series. For the general non-symmetric corrugation shape, the mth band-gap is controlled only by one, the mth, harmonic in the corrugation series. The revealed insights into the mechanism of band-gap formation can be used to predict locations and widths of all frequency band-gaps featured by any corrugation shape. These insights are general and can be valid also for other types of wave motion in periodic structures, e.g., transverse or torsional vibration. PMID:27106336

  16. Time-frequency characterization of rail corrugation under a combined auto-regressive and matched filter scheme

    NASA Astrophysics Data System (ADS)

    Hory, C.; Bouillaut, L.; Aknin, P.

    2012-05-01

    Rail corrugation is an oscillatory mechanical wear of rail surface raising from the long-term interaction between rail and wheel. Signal processing approaches to corrugation monitoring, as recommended by the European standards for instance, are designed either in the mileage domain or in the wavelength domain. However a joint mileage and wavelength domain analysis of the monitoring data can provide crucial information about the simultaneous amplitude and wavelength modulations of the corrugation modes. It is proposed in this paper to perform such a mileage-wavelength domain analysis of rail corrugation using the class of Auto-Regressive-MAtched Filterbank (AR-MAFI) methods. We show that these methods assume a statistical model that fits the corrugation data. We discuss also the optimal parameter settings for the analysis of corrugation data. Experimental studies performed on data collected from the French RATP metro network show that the AR-MAFI methods outperform (in terms of readability and accuracy) the standard distance domain or wavelength domain methods in localizing and characterizing corrugation.

  17. Experimental and numerical investigation of the effect of rail corrugation on the behaviour of rail fastenings

    NASA Astrophysics Data System (ADS)

    Ling, Liang; Li, Wei; Shang, Hongxia; Xiao, Xinbiao; Wen, Zefeng; Jin, Xuesong

    2014-09-01

    This paper presents the results of a detailed investigation of the effects of rail corrugation on the dynamic behaviour of metro rail fastenings, obtained from extensive experiments conducted on site and from simulations of train-track dynamics. The results of tests conducted with a metro train operating on corrugated tracks are presented and discussed first. A three-dimensional (3D) model of the metro train and a slab track was developed using multi-body dynamics modelling and the finite element method to simulate the effect of rail corrugation on the dynamic behaviour of rail fastenings. In the model, the metro train is modelled as a multi-rigid body system, and the slab track is modelled as a discrete elastic support system consisting of two Timoshenko beams for the rails, a 3D solid finite element (FE) model for the slabs, periodic discrete viscoelastic elements for the rail fastenings that connect the rails to the slabs, and uniformly viscoelastic elements for the subgrade beneath the slabs. The proposed train-track model was used to investigate the effects of rail corrugation on the dynamic behaviour of the metro track system and fastenings. An FE model for the rail fastenings was also developed and was used to calculate the stresses in the clips, some of which rupture under the excitation of rail corrugation. The results of the field experiments and dynamics simulations provide an insight into the root causes of the fracture of the clips, and several remedies are suggested for mitigating strong vibrations and failure of metro rail fastening systems.

  18. Research on a 170 GHz, 2 MW coaxial cavity gyrotron with inner-outer corrugation

    SciTech Connect

    Hou, Shenyong; Yu, Sheng; Li, Hongfu

    2015-03-15

    In this paper, a coaxial cavity gyrotron with inner-outer corrugation is researched. The electron kineto-equations and the first order transmission line equations of the gyrotron are derived from Lorentz force equation and the transmission line theory, respectively. And then, a 2 MW, 170 GHz coaxial cavity gyrotron with inner-outer corrugation is designed. By means of numerical calculation, the beam-wave interaction of the coaxial cavity gyrotron with inner-outer corrugation is investigated. Results show that the efficient and the outpower of the gyrotron are 42.3% and 2.38 MW, respectively.

  19. Wedgethread pipe connection

    DOEpatents

    Watts, John D.

    2003-06-17

    Several embodiments of a wedgethread pipe connection are disclosed that have improved makeup, sealing, and non-loosening characteristics. In one embodiment, an open wedgethread is disclosed that has an included angle measured in the gap between the stab flank and the load flank to be not less than zero, so as to prevent premature wedging between mating flanks before the position of full makeup is reached, as does occur between trapped wedgethreads wherein the included angle is less than zero. The invention may be used for pipe threads large or small, as a flush joint, with collars, screwed into plates or it may even be used to reversibly connect such as solid posts to base members where a wide makeup torque range is desired. This Open wedgethread, as opposed to trapped wedgethreads, provides a threaded pipe connection that: is more cost-effective; can seal high pressure gas; can provide selectively a connection strength as high as the pipe strength; assures easy makeup to the desired position of full makeup within a wide torque range; may have a torque strength as high as the pipe torque strength; is easier to manufacture; is easier to gage; and is less subject to handling damage.

  20. Remotely operated pipe connector

    DOEpatents

    Josefiak, Leonard J.; Cramer, Charles E.

    1988-01-01

    An apparatus for remotely assembling and disassembling a Graylock type coctor between a pipe and a closure for the pipe includes a base and a receptacle on the base for the closure. The pipe is moved into position vertically above the closure by a suitable positioning device such that the flange on the pipe is immediately adjacent and concentric with the flange on the closure. A moving device then moves two semicircular collars from a position free of the closure to a position such that the interior cam groove of each collar contacts the two flanges. Finally, a tensioning device automatically allows remote tightening and loosening of a nut and bolt assembly on each side of the collar to cause a seal ring located between the flanges to be compressed and to seal the closure. Release of the pipe and the connector is accomplished in the reverse order. Preferably, the nut and bolt assembly includes an elongate shaft portion on which a removable sleeve is located.

  1. Heat pipes and use of heat pipes in furnace exhaust

    DOEpatents

    Polcyn, Adam D.

    2010-12-28

    An array of a plurality of heat pipe are mounted in spaced relationship to one another with the hot end of the heat pipes in a heated environment, e.g. the exhaust flue of a furnace, and the cold end outside the furnace. Heat conversion equipment is connected to the cold end of the heat pipes.

  2. Apparatus for moving a pipe inspection probe through piping

    DOEpatents

    Zollinger, W. Thor; Appel, D. Keith; Lewis, Gregory W.

    1995-01-01

    A method and apparatus for controllably moving devices for cleaning or inspection through piping systems, including piping systems with numerous piping bends therein, by using hydrostatic pressure of a working fluid introduced into the piping system. The apparatus comprises a reservoir or other source for supplying the working fluid to the piping system, a launch tube for admitting the device into the launcher and a reversible, positive displacement pump for controlling the direction and flow rate of the working fluid. The device introduced into the piping system moves with the flow of the working fluid through the piping system. The launcher attaches to the valved ends of a piping system so that fluids in the piping system can recirculate in a closed loop. The method comprises attaching the launcher to the piping system, supplying the launcher with working fluid, admitting the device into the launcher, pumping the working fluid in the direction and at the rate desired so that the device moves through the piping system for pipe cleaning or inspection, removing the device from the launcher, and collecting the working fluid contained in the launcher.

  3. Apparatus for moving a pipe inspection probe through piping

    DOEpatents

    Zollinger, W.T.; Appel, D.K.; Lewis, G.W.

    1995-07-18

    A method and apparatus are disclosed for controllably moving devices for cleaning or inspection through piping systems, including piping systems with numerous piping bends therein, by using hydrostatic pressure of a working fluid introduced into the piping system. The apparatus comprises a reservoir or other source for supplying the working fluid to the piping system, a launch tube for admitting the device into the launcher and a reversible, positive displacement pump for controlling the direction and flow rate of the working fluid. The device introduced into the piping system moves with the flow of the working fluid through the piping system. The launcher attaches to the valved ends of a piping system so that fluids in the piping system can recirculate in a closed loop. The method comprises attaching the launcher to the piping system, supplying the launcher with working fluid, admitting the device into the launcher, pumping the working fluid in the direction and at the rate desired so that the device moves through the piping system for pipe cleaning or inspection, removing the device from the launcher, and collecting the working fluid contained in the launcher. 8 figs.

  4. Composite drill pipe

    DOEpatents

    Leslie, James C.; Leslie, II, James C.; Heard, James; Truong, Liem , Josephson; Marvin , Neubert; Hans

    2008-12-02

    A composite pipe segment is formed to include tapered in wall thickness ends that are each defined by opposed frustoconical surfaces conformed for self centering receipt and intimate bonding contact within an annular space between corresponding surfaces of a coaxially nested set of metal end pieces. The distal peripheries of the nested end pieces are then welded to each other and the sandwiched and bonded portions are radially pinned. The composite segment may include imbedded conductive leads and the axial end portions of the end pieces are shaped to form a threaded joint with the next pipe assembly that includes a contact ring in one pipe assembly pierced by a pointed contact in the other to connect the corresponding leads across the joint.

  5. Apparatus for inspecting piping

    DOEpatents

    Zollingger, W. Thor; Appel, D. Keith; Park, Larry R.

    1995-01-01

    An inspection rabbit for inspecting piping systems having severe bends therein. The rabbit consists of a flexible, modular body containing a miniaturized eddy current inspection probe, a self-contained power supply for proper operation of the rabbit, an outer surface that allows ease of movement through piping systems and means for transmitting data generated by the inspection device. The body is preferably made of flexible polyvinyl chloride (PVC) tubing or, alternatively, silicone rubber with a shrink wrapping of polytetrafluoroethylene (TEFLON.RTM.). The body is formed to contain the power supply, preferably a plurality of batteries, and a spool of communication wire that connects to a data processing computer external to the piping system.

  6. Heat-pipe Earth.

    PubMed

    Moore, William B; Webb, A Alexander G

    2013-09-26

    The heat transport and lithospheric dynamics of early Earth are currently explained by plate tectonic and vertical tectonic models, but these do not offer a global synthesis consistent with the geologic record. Here we use numerical simulations and comparison with the geologic record to explore a heat-pipe model in which volcanism dominates surface heat transport. These simulations indicate that a cold and thick lithosphere developed as a result of frequent volcanic eruptions that advected surface materials downwards. Declining heat sources over time led to an abrupt transition to plate tectonics. Consistent with model predictions, the geologic record shows rapid volcanic resurfacing, contractional deformation, a low geothermal gradient across the bulk of the lithosphere and a rapid decrease in heat-pipe volcanism after initiation of plate tectonics. The heat-pipe Earth model therefore offers a coherent geodynamic framework in which to explore the evolution of our planet before the onset of plate tectonics. PMID:24067709

  7. Apparatus for inspecting piping

    DOEpatents

    Zollingger, W.T.; Appel, D.K.; Park, L.R.

    1995-03-21

    An inspection rabbit is described for inspecting piping systems having severe bends therein. The rabbit consists of a flexible, modular body containing a miniaturized eddy current inspection probe, a self-contained power supply for proper operation of the rabbit, an outer surface that allows ease of movement through piping systems and means for transmitting data generated by the inspection device. The body is preferably made of flexible polyvinyl chloride (PVC) tubing or, alternatively, silicone rubber with a shrink wrapping of polytetrafluoroethylene (TEFLON{trademark}). The body is formed to contain the power supply, preferably a plurality of batteries, and a spool of communication wire that connects to a data processing computer external to the piping system. 6 figures.

  8. Heat Pipe Technology

    NASA Astrophysics Data System (ADS)

    1981-01-01

    The heat pipe, a sealed chamber whose walls are lined with a "wick," a thin capillary network containing a working fluid in liquid form was developed for a heat distribution system for non-rotating satellites. Use of the heat pipe provides a continuous heat transfer mechanism. "Heat tubes" that improve temperature control in plastics manufacturing equipment incorporated the heat pipe technology. James M. Stewart, an independent consultant, patented the heat tubes he developed and granted a license to Kona Corporation. The Kona Nozzle for heaterless injection molding gets heat for its operation from an external source and has no internal heating bands, reducing machine maintenance and also eliminating electrical hazards associated with heater bands. The nozzles are used by Eastman Kodak, Bic Pen Corporation, Polaroid, Tupperware, Ford Motor Company, RCA, and Western Electric in the molding of their products.

  9. Heat-pipe Earth.

    PubMed

    Moore, William B; Webb, A Alexander G

    2013-09-26

    The heat transport and lithospheric dynamics of early Earth are currently explained by plate tectonic and vertical tectonic models, but these do not offer a global synthesis consistent with the geologic record. Here we use numerical simulations and comparison with the geologic record to explore a heat-pipe model in which volcanism dominates surface heat transport. These simulations indicate that a cold and thick lithosphere developed as a result of frequent volcanic eruptions that advected surface materials downwards. Declining heat sources over time led to an abrupt transition to plate tectonics. Consistent with model predictions, the geologic record shows rapid volcanic resurfacing, contractional deformation, a low geothermal gradient across the bulk of the lithosphere and a rapid decrease in heat-pipe volcanism after initiation of plate tectonics. The heat-pipe Earth model therefore offers a coherent geodynamic framework in which to explore the evolution of our planet before the onset of plate tectonics.

  10. Superfluid Helium Heat Pipe

    NASA Astrophysics Data System (ADS)

    Gully, P.

    This paper reports on the development and the thermal tests of three superfluid helium heat pipes. Two of them are designed to provide a large transport capacity (4 mW at 1.7 K). They feature a copper braid located inside a 6 mm outer diameter stainless tube fitted with copper ends for mechanical anchoring. The other heat pipe has no copper braid and is designed to get much smaller heat transport capacity (0.5 mW) and to explore lower temperature (0.7 - 1 K). The copper braid and the tube wall is the support of the Rollin superfluid helium film in which the heat is transferred. The low filling pressure makes the technology very simple with the possibility to easily bend the tube. We present the design and discuss the thermal performance of the heat pipes tested in the 0.7 to 2.0 K temperature range. The long heat pipe (1.2 m with copper braid) and the short one (0.25 m with copper braid) have similar thermal performance in the range 0.7 - 2.0 K. At 1.7 K the long heat pipe, 120 g in weight, reaches a heat transfer capacity of 6.2 mW and a thermal conductance of 600 mW/K for 4 mW transferred power. Due to the pressure drop of the vapor flow and Kapitza thermal resistance, the conductance of the third heat pipe dramatically decreases when the temperature decreases. A 3.8 mW/K is obtained at 0.7 K for 0.5 mW transferred power.

  11. Heat pipe array heat exchanger

    DOEpatents

    Reimann, Robert C.

    1987-08-25

    A heat pipe arrangement for exchanging heat between two different temperature fluids. The heat pipe arrangement is in a ounterflow relationship to increase the efficiency of the coupling of the heat from a heat source to a heat sink.

  12. Heat transfer in pipes

    NASA Technical Reports Server (NTRS)

    Burbach, T.

    1985-01-01

    The heat transfer from hot water to a cold copper pipe in laminar and turbulent flow condition is determined. The mean flow through velocity in the pipe, relative test length and initial temperature in the vessel were varied extensively during tests. Measurements confirm Nusselt's theory for large test lengths in laminar range. A new equation is derived for heat transfer for large starting lengths which agrees satisfactorily with measurements for large starting lengths. Test results are compared with the new Prandtl equation for heat transfer and correlated well. Test material for 200- and to 400-diameter test length is represented at four different vessel temperatures.

  13. Pipe Drafting with CAD. Teacher Edition.

    ERIC Educational Resources Information Center

    Smithson, Buddy

    This teacher's guide contains nine units of instruction for a course on computer-assisted pipe drafting. The course covers the following topics: introduction to pipe drafting with CAD (computer-assisted design); flow diagrams; pipe and pipe components; valves; piping plans and elevations; isometrics; equipment fabrication drawings; piping design…

  14. Flat-plate heat pipe

    NASA Technical Reports Server (NTRS)

    Marcus, B. D.; Fleischman, G. L. (Inventor)

    1977-01-01

    Flat plate (vapor chamber) heat pipes were made by enclosing metal wicking between two capillary grooved flat panels. These heat pipes provide a unique configuration and have good capacity and conductance capabilities in zero gravity. When these flat plate vapor chamber heat pipes are heated or cooled, the surfaces are essentially isothermal, varying only 3 to 5 C over the panel surface.

  15. Analysis of a disk-on-rod surface wave element inside a corrugated horn using the mode-matching technique

    NASA Technical Reports Server (NTRS)

    Chen, J. C.

    1995-01-01

    A disk-on-rod inside a corrugated horn is one of the horn configurations for dual-frequency or wide-band operation. A mode-matching analysis method is described. A disk-on-rod inside a corrugated horn is represented as a series of coaxial waveguide sections and circular waveguide sections connected to each other. Three kinds of junctions need to be considered: coaxial-to-coaxial, coaxial-to-circular, and circular-to-circular. A computer program was developed to calculate the scattering matrix and the radiation pattern of a disk-on-rod inside a corrugated horn. The software as verified by experiment, and good agreement between calculation and measurement was obtained. The disk-on-rod inside a corrugated horn design gives an option to the Deep Space Network dual-frequency operation system, which currently is a two-horn/one-dichroic plate system.

  16. Reusable high-temperature heat pipes and heat pipe panels

    NASA Technical Reports Server (NTRS)

    Camarda, Charles J. (Inventor); Ransone, Philip O. (Inventor)

    1989-01-01

    A reusable, durable heat pipe which is capable of operating at temperatures up to about 3000 F in an oxidizing environment and at temperatures above 3000 F in an inert or vacuum environment is produced by embedding a refractory metal pipe within a carbon-carbon composite structure. A reusable, durable heat pipe panel is made from an array of refractory-metal pipes spaced from each other. The reusable, durable, heat-pipe is employed to fabricate a hypersonic vehicle leading edge and nose cap.

  17. Particle trap to sheath contact for a gas-insulated transmission line having a corrugated outer conductor

    DOEpatents

    Fischer, William H.; Cookson, Alan H.; Yoon, Kue H.

    1984-04-10

    A particle trap to outer elongated conductor or sheath contact for gas-insulated transmission lines. The particle trap to outer sheath contact of the invention is applicable to gas-insulated transmission lines having either corrugated or non-corrugated outer sheaths. The contact of the invention includes an electrical contact disposed on a lever arm which in turn is rotatably disposed on the particle trap and biased in a direction to maintain contact between the electrical contact and the outer sheath.

  18. Heat pipe investigations

    NASA Technical Reports Server (NTRS)

    Marshburn, J. P.

    1973-01-01

    Techniques associated with thermal-vacuum and bench testing, along with flight testing of the OAO-C spacecraft heat pipes are outlined, to show that the processes used in heat transfer design and testing are adequate for good performance evaluations.

  19. Aeronautical tubes and pipes

    NASA Astrophysics Data System (ADS)

    Beauclair, N.

    1984-12-01

    The main and subcomponent French suppliers of aircraft tubes and pipes are discussed, and the state of the industry is analyzed. Quality control is essential for tubes with regard to their i.d. and metallurgical compositions. French regulations do not allow welded seam tubes in hydraulic circuits unless no other form is available, and then rustproofed steel must be installed. The actual low level of orders for any run of tubes dictates that the product is only one of several among the manufacturers' line. Automation, both in NDT and quality control, assures that the tubes meet specifications. A total of 10 French companies participate in the industry, serving both civil and military needs, with some companies specializing only in titanium, steel, or aluminum materials. Concerns wishing to enter the market must upgrade their equipment to meet the higher aeronautical specifications and be prepared to furnish tubes and pipes that serve both functional and structural purposes simultaneously. Additionally, pipe-bending machines must also perform to tight specifications. Pipes can range from 0.2 mm exterior diameter to 40 mm, with wall thicknesses from 0.02 mm to 3 mm. A chart containing a list of manufacturers and their respective specifications and characteristics is presented, and a downtrend in production with reduction of personnel is noted.

  20. A performance-enhanced energy harvester for low frequency vibration utilizing a corrugated cantilevered beam

    NASA Astrophysics Data System (ADS)

    Kim, In-Ho; Jin, SeungSeop; Jang, Seon-Jun; Jung, Hyung-Jo

    2014-03-01

    This note proposes a performance-enhanced piezoelectric energy harvester by replacing a conventional flat cantilevered beam with a corrugated beam. It consists of a proof mass and a sinusoidally or trapezoidally corrugated cantilevered beam covered by a polyvinylidene fluoride (PVDF) film. Compared to the conventional energy harvester of the same size, it has a more flexible bending stiffness and a larger bonding area of the PVDF layer, so higher output voltage from the device can be expected. In order to investigate the characteristics of the proposed energy harvester, analytical developments and numerical simulations on its natural frequency and tip displacement are carried out. Shaking table tests are also conducted to verify the performance of the proposed device. It is clearly shown from the tests that the proposed energy harvester not only has a lower natural frequency than an equivalent sized standard energy harvester, but also generates much higher output voltage than the standard one.

  1. Enhanced response and sensitivity of self-corrugated graphene sensors with anisotropic charge distribution

    PubMed Central

    Yol Jeong, Seung; Jeong, Sooyeon; Won Lee, Sang; Tae Kim, Sung; Kim, Daeho; Jin Jeong, Hee; Tark Han, Joong; Baeg, Kang-Jun; Yang, Sunhye; Seok Jeong, Mun; Lee, Geon-Woong

    2015-01-01

    We introduce a high-performance molecular sensor using self-corrugated chemically modified graphene as a three dimensional (3D) structure that indicates anisotropic charge distribution. This is capable of room-temperature operation, and, in particular, exhibiting high sensitivity and reversible fast response with equilibrium region. The morphology consists of periodic, “cratered” arrays that can be formed by condensation and evaporation of graphene oxide (GO) solution on interdigitated electrodes. Subsequent hydrazine reduction, the corrugated edge area of the graphene layers have a high electric potential compared with flat graphene films. This local accumulation of electrons interacts with a large number of gas molecules. The sensitivity of 3D-graphene sensors significantly increases in the atmosphere of NO2 gas. The intriguing structures have several advantages for straightforward fabrication on patterned substrates, high-performance graphene sensors without post-annealing process. PMID:26053892

  2. Enhanced response and sensitivity of self-corrugated graphene sensors with anisotropic charge distribution

    NASA Astrophysics Data System (ADS)

    Yol Jeong, Seung; Jeong, Sooyeon; Won Lee, Sang; Tae Kim, Sung; Kim, Daeho; Jin Jeong, Hee; Tark Han, Joong; Baeg, Kang-Jun; Yang, Sunhye; Seok Jeong, Mun; Lee, Geon-Woong

    2015-06-01

    We introduce a high-performance molecular sensor using self-corrugated chemically modified graphene as a three dimensional (3D) structure that indicates anisotropic charge distribution. This is capable of room-temperature operation, and, in particular, exhibiting high sensitivity and reversible fast response with equilibrium region. The morphology consists of periodic, “cratered” arrays that can be formed by condensation and evaporation of graphene oxide (GO) solution on interdigitated electrodes. Subsequent hydrazine reduction, the corrugated edge area of the graphene layers have a high electric potential compared with flat graphene films. This local accumulation of electrons interacts with a large number of gas molecules. The sensitivity of 3D-graphene sensors significantly increases in the atmosphere of NO2 gas. The intriguing structures have several advantages for straightforward fabrication on patterned substrates, high-performance graphene sensors without post-annealing process.

  3. Enhanced response and sensitivity of self-corrugated graphene sensors with anisotropic charge distribution.

    PubMed

    Jeong, Seung Yol; Jeong, Sooyeon; Lee, Sang Won; Kim, Sung Tae; Kim, Daeho; Jeong, Hee Jin; Han, Joong Tark; Baeg, Kang-Jun; Yang, Sunhye; Jeong, Mun Seok; Lee, Geon-Woong

    2015-01-01

    We introduce a high-performance molecular sensor using self-corrugated chemically modified graphene as a three dimensional (3D) structure that indicates anisotropic charge distribution. This is capable of room-temperature operation, and, in particular, exhibiting high sensitivity and reversible fast response with equilibrium region. The morphology consists of periodic, "cratered" arrays that can be formed by condensation and evaporation of graphene oxide (GO) solution on interdigitated electrodes. Subsequent hydrazine reduction, the corrugated edge area of the graphene layers have a high electric potential compared with flat graphene films. This local accumulation of electrons interacts with a large number of gas molecules. The sensitivity of 3D-graphene sensors significantly increases in the atmosphere of NO2 gas. The intriguing structures have several advantages for straightforward fabrication on patterned substrates, high-performance graphene sensors without post-annealing process. PMID:26053892

  4. Structural testing of corrugated asbestos-cement roof panels at the Hanford Facilities, Richland, Washington

    SciTech Connect

    Moustafa, S.E.; Rodehaver, S.M.; Frier, W.A.

    1993-10-01

    This report describes a roof testing program that was carried out at the 105KE/KW Spent Fuel Storage Basins and their surrounding facilities at the Hanford Site in Richland, Washington. The roof panels were constructed in the mid 1950`s of corrugated asbestos-cement (A/C), which showed common signs of aging. Based on the construction specifications, the panels capacity to meet current design standards was questioned. Both laboratory and in-situ load testing of the corrugated A/C panels was conducted. The objective of the complete test program was to determine the structural integrity of the existing A/C roof panels installed in the 105KE and 105KW facilities. The data from these tests indicated that the roofs are capable of resisting the design loads and are considered safe. A second phase test to address the roof resistance to personnel and roof removal/roofing system installation equipment was recommended and is underway.

  5. Corrugated structure insertion for extending the SASE bandwidth up to 3% at the European XFEL

    NASA Astrophysics Data System (ADS)

    Zagorodnov, I.; Feng, G.; Limberg, T.

    2016-11-01

    The usage of x-ray free electron laser (XFEL) in femtosecond nanocrystallography involves sequential illumination of many small crystals of arbitrary orientation. Hence a wide radiation bandwidth will be useful in order to obtain and to index a larger number of Bragg peaks used for determination of the crystal orientation. Considering the baseline configuration of the European XFEL in Hamburg, and based on beam dynamics simulations, we demonstrate here that the usage of corrugated structures allows for a considerable increase in radiation bandwidth. Data collection with a 3% bandwidth, a few microjoule radiation pulse energy, a few femtosecond pulse duration, and a photon energy of 5.4 keV is possible. For this study we have developed an analytical modal representation of the short-range wake function of the flat corrugated structures for arbitrary offsets of the source and the witness particles.

  6. Low-Frequency Quasi-Periodic Oscillations and Iron Line Variability of Discoseismic Corrugation Modes

    NASA Astrophysics Data System (ADS)

    Butsky, Iryna; Tsang, D.

    2013-01-01

    Using a fast semi-analytic raytracing code, we study the variability of iron lines due to discoseismic oscillations concentrated in the inner-most regions of accretion discs around black holes. The dependence of the relativistically broadened line profile on the oscillation-phase is studied for discoseismic corrugation modes. The corrugation mode, or c-mode, is of particular interest as their natural frequency corresponds well to the 0.1-10 Hz range observed for low-frequency quasi-periodic oscillations (LFQPOs) in X-ray binaries. Comparison of the oscillation phase dependent variability and QPO-phase stacked Fe-Kalpha line observations will allow such discoseismic models to be confirmed or ruled out as a source of LFQPOs.

  7. Long-range spoof surface plasmons on the doubly corrugated metal surfaces

    NASA Astrophysics Data System (ADS)

    Liu, Yong-Qiang; Kong, Ling-Bao; Liu, Pu-Kun

    2016-07-01

    In this paper, symmetric spoof surface plasmon (SSP) mode on the doubly corrugated metal surfaces is indentified as long-range spoof surface plasmon (LRSSP) because of its extreme low propagation loss and symmetric dominant field profile so as short-range SSP (SRSSP) for anti-symmetric mode. Based on theoretical calculation and numerical simulation of finite integration method, symmetric and anti-symmetric SSP modes with various gap sizes between these two identical corrugated metal surfaces are investigated in terahertz (THz) regime and good agreement is realized. Besides, the low loss superiority of LRSSP diminishes along with the increased gap size. This work opens up new avenues to utilize this long-range surface mode in far-infrared, THz or lower frequency band and can find many potential applications such as low-loss waveguide, filters and novel electronic sources.

  8. Wavelength filtering and demultiplexing devices based on ultrathin corrugated MIM waveguides

    NASA Astrophysics Data System (ADS)

    Yang, Bao Jia; Zhou, Yong Jin

    2016-05-01

    We have numerically investigated the transmission properties of spoof surface plasmon polaritons on the ultrathin corrugated metal-insulator-metal (MIM) waveguides with different grooves. A band-pass plasmonic filter with T-shaped grooves and a compact 4-way wavelength division demultiplexing (WDM) incorporating the filter have been proposed. The whole 4-way WDM is more compact by the use of corrugated MIM waveguides with meander grooves. The near electric field distributions show that electromagnetic waves at different frequencies are guided and propagate along different branches with good isolation between branches. The experimental and numerical results have shown good agreements and validated the functions of the 4-way wavelength splitter. We also numerically investigate the 4-way WDM at terahertz frequencies by scaling down the whole structure. It is believed that the spoof plasmonic devices can find more applications in the plasmonic integration platform, such as optical communications, signal processing and spectral engineering.

  9. Quasiclassical trajectory studies of rigid rotor--rigid surface scattering. II. Corrugated surface

    SciTech Connect

    Park, S.C.; Bowman, J.M.

    1984-03-01

    The quasiclassical trajectory method, previously applied to rigid rotor--rigid flat surface scattering (J. M. Bowman and S. C. Park, J. Chem. Phys. 77, 5441 (1982)) is applied to a rigid rotor--rigid corrugated surface, i.e., a N/sub 2/--LiF(001), system. The mechanisms for rotational excitation at low and high collision energies are studied as well as their dependence on initial beam orientation and corrugation strength. A significant correlation between long-lived trajectories and high rotational excitation is found for low energy collisions and rotational rainbows are clearly observed in the high energy regime, although these features are broadened relative to the flat surface reported previously.

  10. Tailoring the surface of ZnO nanorods into corrugated nanorods via a selective chemical etch method

    NASA Astrophysics Data System (ADS)

    Duan, Xiangyang; Chen, Guangde; Li, Chu; Yin, Yuan; Jin, Wentao; Guo, Lu'an; Ye, Honggang; Zhu, Youzhang; Wu, Yelong

    2016-07-01

    Using the chemical vapour deposition method, we successfully converted smooth ZnO nanorods (NRs) into corrugated NRs by simply increasing the reaction time. The surface morphology and crystallographic structure of the corrugated NRs were investigated. The corrugated NRs were decorated by alternant (11\\bar{2}1) and (11\\bar{2}\\bar{1}) planes at the exposed side surfaces while the conventional \\{10\\bar{1}0\\} planes disappeared. No twinning boundaries were found in the periodically corrugated structures, indicating that they were type II corrugated NRs. Further investigation told us that they were selectively etched. We introduced a hydrothermal method to synthesize the smooth ZnO NRs and then etched them in a tube furnace at 950 °C with a flow of carbon monoxide. By separating the growth stage and the selective etching stage, we explicitly demonstrated a successfully selective etching effect on ZnO NRs with a carbon monoxide reducing atmosphere for the first time. An etching mechanism based on the selective reaction between carbon monoxide and the different exposed surfaces was proposed. Our results will improve the understanding of the growth mechanism on coarse or corrugated NRs and provide a new strategy for the application of surface controlled nanostructured materials.

  11. Tailoring the surface of ZnO nanorods into corrugated nanorods via a selective chemical etch method.

    PubMed

    Duan, Xiangyang; Chen, Guangde; Li, Chu; Yin, Yuan; Jin, Wentao; Guo, Lu'an; Ye, Honggang; Zhu, Youzhang; Wu, Yelong

    2016-07-22

    Using the chemical vapour deposition method, we successfully converted smooth ZnO nanorods (NRs) into corrugated NRs by simply increasing the reaction time. The surface morphology and crystallographic structure of the corrugated NRs were investigated. The corrugated NRs were decorated by alternant [Formula: see text] and [Formula: see text] planes at the exposed side surfaces while the conventional [Formula: see text] planes disappeared. No twinning boundaries were found in the periodically corrugated structures, indicating that they were type II corrugated NRs. Further investigation told us that they were selectively etched. We introduced a hydrothermal method to synthesize the smooth ZnO NRs and then etched them in a tube furnace at 950 °C with a flow of carbon monoxide. By separating the growth stage and the selective etching stage, we explicitly demonstrated a successfully selective etching effect on ZnO NRs with a carbon monoxide reducing atmosphere for the first time. An etching mechanism based on the selective reaction between carbon monoxide and the different exposed surfaces was proposed. Our results will improve the understanding of the growth mechanism on coarse or corrugated NRs and provide a new strategy for the application of surface controlled nanostructured materials. PMID:27276661

  12. Heat Pipes Cool Power Magnetics

    NASA Technical Reports Server (NTRS)

    Hansen, I.; Chester, M.; Luedke, E.

    1983-01-01

    Configurations originally developed for space use are effective in any orientation. Heat pipes integrated into high-power, high-frequency, highvoltage spaceflight magnetics reduce weight and improve reliability by lowering internal tempertures. Two heat pipes integrated in design of power transformer cool unit in any orientation. Electrostatic shield conducts heat from windings to heat pipe evaporator. Technology allows dramatic reductions in size and weight, while significantly improving reliability. In addition, all attitude design of heat pipes allows operation of heat pipes independent of local gravity forces.

  13. Corrugation-pitch-modulated DFB semiconductor lasers realized by common holographic exposure

    NASA Astrophysics Data System (ADS)

    Li, Simin; Li, Lianyan; Shi, Yuechun; Cao, Baoli; Guo, Renjia; Zheng, Junshou; Chen, Xiangfei

    2014-07-01

    Experimental results of corrugation-pitch-modulated (CPM) DFB lasers with distributed phase shift (DPS) based on reconstruction-equivalent-chirp (REC) technique are demonstrated. The DPS can flatten the light intensity distribution along the laser cavity and reduce the spatial hole burning (SHB). The lasers have good single longitudinal mode (SLM) property even under high injection current. Thanks to the sampling technique, the grating can be easily fabricated by holographic exposure and conventional lithograph.

  14. Improved manufacturability and characterization of a corrugated Parylene diaphragm pressure transducer

    NASA Astrophysics Data System (ADS)

    Luharuka, Rajesh; Noh, Hongseok Moses; Kim, Sang Kyung; Mao, Hua; Wong, Lid; Hesketh, Peter J.

    2006-08-01

    Corrugated Parylene diaphragm based pressure transducers have been used in a wide range of MEMS devices. This paper presents a reusable silicon micromold based process to fabricate optically reflective, corrugated Parylene diaphragms for fiber-optic-linked pressure sensing in an ultralow pressure range (±98 Pa). The silicon micromolding process is combined with a novel chip-level tube bonding method to mount the diaphragms to the end of a tube before releasing them from the mold. This fabrication approach vastly improves the manufacturability of these pressure sensors over the previously used photoresist mold-based process. It provides greater flexibility in design and is shown to produce Parylene diaphragms with an accurate corrugation profile. Such a biomedical ultralow pressure sensor can be attached to a catheter tip and used in confined space for intra-cavity pressure measurements. Fabrication and testing results related to six different corrugated diaphragm designs have been presented here. These diaphragms are characterized in the operating pressure range (±98 Pa) with a 5 Pa resolution using an optical profilometer and U-tube manometer setup. The sensor characterization results show that all three designs of 1.0 mm diameter diaphragms have good agreement with the predicted values that were obtained from finite element analysis. Deflections of up to 6 µm were measured in these diaphragms. Larger displacements of up to 19 µm were obtained in 1.5 mm diameter diaphragms. However, the characteristic curve obtained in these sensors differed significantly from the simulated results. Higher initial deflection due to stress release, localized buckling and lower stiffness of the SU-8 support ring are believed to be the reason behind such deviation from the design values.

  15. Effects of Antimicrobial Peptide Revealed by Simulations: Translocation, Pore Formation, Membrane Corrugation and Euler Buckling

    PubMed Central

    Chen, Licui; Jia, Nana; Gao, Lianghui; Fang, Weihai; Golubovic, Leonardo

    2013-01-01

    We explore the effects of the peripheral and transmembrane antimicrobial peptides on the lipid bilayer membrane by using the coarse grained Dissipative Particle Dynamics simulations. We study peptide/lipid membrane complexes by considering peptides with various structure, hydrophobicity and peptide/lipid interaction strength. The role of lipid/water interaction is also discussed. We discuss a rich variety of membrane morphological changes induced by peptides, such as pore formation, membrane corrugation and Euler buckling. PMID:23579956

  16. MTR BUILDING, TRA603. EAST SIDE. CAMERA FACING WEST. CORRUGATED IRON ...

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

    MTR BUILDING, TRA-603. EAST SIDE. CAMERA FACING WEST. CORRUGATED IRON BUILDING MARKED WITH "X" IS TRA-651. TRA-626, TO ITS RIGHT, HOUSED COMPRESSOR EQUIPMENT FOR THE AIRCRAFT NUCLEAR PROPULSION PROGRAM. LATER, IT WAS USED FOR STORAGE. INL NEGATIVE NO. HD46-42-4. Mike Crane, Photographer, April 2005 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  17. Effects of antimicrobial peptide revealed by simulations: translocation, pore formation, membrane corrugation and euler buckling.

    PubMed

    Chen, Licui; Jia, Nana; Gao, Lianghui; Fang, Weihai; Golubovic, Leonardo

    2013-04-11

    We explore the effects of the peripheral and transmembrane antimicrobial peptides on the lipid bilayer membrane by using the coarse grained Dissipative Particle Dynamics simulations. We study peptide/lipid membrane complexes by considering peptides with various structure, hydrophobicity and peptide/lipid interaction strength. The role of lipid/water interaction is also discussed. We discuss a rich variety of membrane morphological changes induced by peptides, such as pore formation, membrane corrugation and Euler buckling.

  18. Experimental investigation on the dynamic response of clamped corrugated sandwich plates subjected to underwater impulsive loadings

    NASA Astrophysics Data System (ADS)

    Huang, Wei; Zhang, Wei; Li, Dacheng; Hypervelocity Impact Research Center Team

    2015-06-01

    Corrugated sandwich plates are widely used in marine industry because such plates have high strength-to-weight ratios and blast resistance. The laboratory-scaled fluid-structure interaction experiments are performed to demonstrate the shock resistance of solid monolithic plates and corrugated sandwich plates by quantifying the permanent transverse deflection at mid-span of the plates as a function of impulsive loadings per areal mass. Sandwich structures with 6mm-thick and 10mm-thick 3003 aluminum corrugated core and 5A06 face sheets are compared with the 5A06 solid monolithic plates in this paper. The dynamic deformation of plates are captured with the the 3D digital speckle correlation method (DIC). The results affirm that sandwich structures show a 30% reduction in the maximum plate deflection compare with a monolithic plate of identical mass per unit area, and the peak value of deflection effectively reduced by increasing the thickness core. The failure modes of sandwich plates consists of core crushing, imprinting, stretch tearing of face sheets, bending and permanent deformation of entire structure with the increasing impulsive loads, and the failure mechanisms are analyzed with the postmortem panels and dynamic deflection history captured by cameras. National Natural Science Foundation of China (NO.: 11372088).

  19. Gap opening in graphene by 1D and 2D periodic corrugations

    NASA Astrophysics Data System (ADS)

    Naumov, Ivan; Bratkovsky, Alexander

    2012-02-01

    Using first-principles methods and symmetry arguments, we show that a graphene monolayer, which is periodically corrugated in one or two direction(s), can be either semimetal or semiconductor, depending on how strong corrugation is or how the initial symmetry is broken. In the case of 1D periodic ripples, a gap at the Dirac points opens up only due to (i) breaking of the inversion symmetry or equivalence between A and B sublattices and/or (ii) merging of two inequivalent Dirac points, D and -D. Since breaking the inversion symmetry has only relatively modest effect, a tangible gap can be mainly induced by mutual annihilation of the Dirac points, which requires large corrugations, close to mechanical breaking point. In contrast to 1D, the 2D ripples can additionally induce a semiconducting gap via mixing of electronic states belonging to two different K, K' valleys. In this case, a gap on the order of 0.5 eV can be opened up at strains safely lower than the graphene failure strain [1]. [4pt] [1] I.I. Naumov, A.M. Bratkovsky, arXiv:1104.0314v1.

  20. Evaporation characteristics of R22 flowing inside a corrugated tube. [Tubes with indented spiral turbulence promoter

    SciTech Connect

    Hinton, D.L. ); Conklin, J.C.; Vineyard, E.A. )

    1992-01-01

    Because heat exchanger thermal performance has a direct influence on the overall cycle performance of vapor-compression refrigeration machinery, enhanced heat transfer surfaces are of interest to improve the efficiency of heat pumps and air conditioners. As part of a larger program investigating nonazeotropic refrigerant mixtures for replacement of chlorofluorocarbon compounds, we investigated the performance of R22 (chlorodifluoromethane) in conventional smooth tubes and enhanced heat transfer tube geometries as a base case. This paper presents the results of this initial investigation for a smooth tube and a tube with a commonly available enhanced heat transfer surface, called corrugated or spirally indented. We investigated the evaporating heat transfer and pressure drop characteristics in an experimental apparatus consisting of a variable-speed compressor and two sets of counterflow concentric-tube heat exchangers having both smooth and corrugated enhanced tubeside surfaces. The refrigerant circulates inside the central tube and water circulates in the annulus. The measured pressure drop and the heat transfer coefficient for the evaporation of the R22 are presented as a function of heat flux, quality, and mass flux for both heat transfer surfaces. Both the heat transfer coefficient and the pressure drop of the corrugated surface are higher than those of the smooth surface at any given refrigerant condition. The heat transfer enhancement is most notable at low mass qualities.

  1. Impact of Atomic Corrugation on Sliding Friction as Probed by QCM

    NASA Astrophysics Data System (ADS)

    Coffey, Tonya; Lee, Sang; Krim, Jacqueline

    2004-03-01

    At the atomic scale, friction is believed to originate primarily via sliding induced excitation of phonons. [1] Theoretical predictions of the magnitude of phononic dissipation have been related to the atomic corrugation of the adsorbate/substrate potential. [2] Braun and colleagues [3] measured a corrugation of 1.9 meV for xenon on a copper(111) surface using helium atom scattering. Using the Quartz Crystal Microbalance (QCM), we have measured the sliding friction of Xe/Cu(111) adsorbed at 77 K. The QCM probe of sliding friction is the sliptime, which measures the slippage of the adsorbate atop the oscillating surface of the QCM. For monolayer coverages, we observed a sliptime of 10 ns for Xe/Cu(111). We also discuss theoretical predictions for the impact of atomic corrugation on sliding friction. [1] Fundamentals of Friction; Macroscopic and Microscopic Processes, ed. I.L. Singer and H.M. Pollock, Kluwer, Dordrecht (1992). [2] M. Cieplak, E.D. Smith, and M.O. Robbins, Science 265 (1994) 1209. [3] J. Braun et al., PRL 80 (1998) 125.

  2. Molecular dynamics simulation of atomic-scale frictional behavior of corrugated nano-structured surfaces.

    PubMed

    Kim, Hyun-Joon; Kim, Dae-Eun

    2012-07-01

    Surface morphology is one of the critical parameters that affect the frictional behavior of two contacting bodies in relative motion. It is important because the real contact area as well as the contact stiffness is dictated by the micro- and nano-scale geometry of the surface. In this regard, the frictional behavior may be controlled by varying the surface morphology through nano-structuring. In this study, molecular dynamics simulations were conducted to investigate the effects of contact area and structural stiffness of corrugated nano-structures on the fundamental frictional behavior at the atomic-scale. The nano-structured surface was modeled as an array of corrugated carbon atoms with a given periodicity. It was found that the friction coefficient of the nano-structured surface was lower than that of a smooth surface under specific contact conditions. The effect of applied load on the friction coefficient was dependent on the size of the corrugation. Furthermore, stiffness of the nano-structure was identified to be an important variable in dictating the frictional behavior.

  3. Atomic force spectroscopy and density-functional study of graphene corrugation on Ru(0001)

    NASA Astrophysics Data System (ADS)

    Voloshina, Elena; Dedkov, Yuriy

    2016-06-01

    Graphene, the thinnest material in the world, can form moiré structures on different substrates, including graphite, h -BN, or metal surfaces. In such systems, the structure of graphene, i.e., its corrugation, as well as its electronic and elastic properties, are defined by the combination of the system geometry and local interaction strength at the interface. The corrugation in such structures on metals is heavily extracted from diffraction or local probe microscopy experiments, and it can be obtained only via comparison with theoretical data, which usually simulate the experimental findings. Here we show that graphene corrugation on metals can be measured directly employing atomic force spectroscopy, and the obtained value coincides with state-of-the-art theoretical results. The presented results demonstrate an unexpected space selectivity for the Δ f (z ) signal in the atomic force spectroscopy in the moiré graphene lattice on Ru(0001), which is explained by the different response of the graphene layer on the indentation process. We also address the elastic reaction of the formed graphene nanodoms on the indentation process by the scanning tip that is important for the modeling and fabrication of graphene-based nanoresonators on the nanoscale.

  4. Investigations of heat transfer and friction characteristics of compact cross-corrugated recuperators

    NASA Astrophysics Data System (ADS)

    Zhou, Guo-Yan; Tu, Shan-Tung; Ma, Hu-gen

    2014-09-01

    As one of the key devices in the high temperature gas turbine system, cross-corrugated recuperators provide high heat transfer capabilities with compact size, light weight, strong mechanical strength and are mandatory to achieve 30 % electrical efficiency or higher for micro turbine engines. Flow in such geometries is usually laminar with lower Reynolds numbers. In order to understand mechanisms of flowing and heat transfer, periodic fully developed fluid flow and heat transfer in two types of cross-corrugated structures with inclination angle at 90° are investigated numerically and experimentally. Periodicity was used to reduce the complexity of the channel geometry and enables the smallest possible segment of the flow channel to be modeled. The velocity and temperature distributions were obtained in the three-dimensional complex domain. Besides a detailed flow analysis, comparison of the local heat and mass transfer and the pressure losses for these geometries are presented. It is shown that the flow phenomena caused by the different geometries were of significant influence on the homogeneity and on the quantity of the local heat and mass transfer as well as on the pressure drop. As a recuperator for micro turbine engines, cross-corrugated sinusoidal channels are more preferable to triangular channels.

  5. Fabrication and evaluation of superplastically formed/weld-brazed corrugated compression panels with beaded webs

    NASA Technical Reports Server (NTRS)

    Royster, D. M.; Davis, R. C.; Shinn, J. M., Jr.; Bales, T. T.; Wiant, H. R.

    1985-01-01

    A study was made to investigate the feasibility of superplastically forming corrugated panels with beaded webs and to demonstrate the structural integrity of these panels by testing. The test panels in the study consist of superplastically formed titanium alloy Ti-6Al-4V half-hat elements that are joined by weld-brazing to titanium alloy Ti-6Al-4V caps to form either single-corrugation compression panels or multiple-corrugation compression panels. Stretching and subsequent thinning of the titanium sheet during superplastic forming is reduced by approximately 35 percent with a shallow half-hat die concept instead of a deep die concept and results in a more uniform thickness across the beaded webs. The complete panels are tested in end compression at room temperature and the results compared with analysis. The heavily loaded panels failed at loads approaching the yield strength of the titanium material. At maximum load, the caps wrinkled locally accompanied with separation of the weld-braze joint in the wrinkle. None of the panels tested, however, failed catastrophically in the weld-braze joint. Experimental test results are in good agreement with structural analysis of the panels.

  6. Corrugated Waveguide and Directional Coupler for CW 250-GHz Gyrotron DNP Experiments

    PubMed Central

    Woskov, Paul P.; Bajaj, Vikram S.; Hornstein, Melissa K.; Temkin, Richard J.; Griffin, Robert G.

    2007-01-01

    A 250-GHz corrugated transmission line with a directional coupler for forward and backward power monitoring has been constructed and tested for use with a 25-W continuous-wave gyrotron for dynamic nuclear polarization (DNP) experiments. The main corrugated line (22-mm internal diameter, 2.4-m long) connects the gyrotron output to the DNP probe input. The directional coupler, inserted approximately midway, is a four-port crossed waveguide beamsplitter design. Two beamsplitters, a quartz plate and ten-wire array, were tested with output coupling of 2.5% (−16 dB) at 250.6 GHz and 1.6% (−18 dB), respectively. A pair of mirrors in the DNP probe transferred the gyrotron beam from the 22-mm waveguide to an 8-mm helically corrugated waveguide for transmission through the final 0.58-m distance inside the NMR magnet to the sample. The transmission-line components were all cold tested with a 248 ± 4-GHz radiometer. A total insertion loss of 0.8 dB was achieved for HE11 -mode propagation from the gyrotron to the sample with only 1% insertion loss for the 22-mm-diameter waveguide. A clean Gaussian gyrotron beam at the waveguide output and reliable forward power monitoring were achieved for many hours of continuous operation. PMID:17901907

  7. Fast diffusion along defects and corrugations in phospholipid P beta, liquid crystals.

    PubMed Central

    Schneider, M B; Chan, W K; Webb, W W

    1983-01-01

    The diffusion of a fluorescent lipid analogue in liquid crystals of the anisotropic P beta, phase of dimyristoylphosphatidylcholine (DMPC) had been found to be highly variable, suggesting structural defect pathways. Fluorescence photobleaching recovery (FPR) experiments imply two effective diffusion pathways with coefficients differing by at least 100. This is consistent with fast diffusion along submicroscopic bands of disordered material ("defects") in the bilayer corrugations characteristic of this phase. Due to strains during transformation from the L alpha phase, the axis of the corrugations is ordinarily disrupted by mosaic patches rotationally disoriented within the mean plane of the molecular bilayers, although larger oriented domains are sometimes adventitiously aligned into microscopically visible striped textures. The corrugations are also systematically aligned along positive disclinations pairs or "oily streaks." Thus, fast diffusion occurs parallel to the disclination lines and along the textured stripes. FPR results yield an upper limit on the effective diffusion in the ordered material of D less than or equal to 2 X 10(-16) cm2/s at 22 degrees C, D less than or equal to 3 X 10(-17) cm2/s at 13 degrees C. In contrast the diffusion coefficient along defect pathways where disordered ribbons are aligned is D approximately 4 X 10(-11) cm2/s at 16 degrees C. Images FIGURE 4 FIGURE 6 FIGURE 7 PMID:6616004

  8. The Band-Gap and TRUE Band-Gap in Nominally Metallic Carbon Nanotubes: the Tight-Binding Study on Corrugation Effect

    NASA Astrophysics Data System (ADS)

    Lu, Hongxia; Wu, Jianbao; Wang, Jizhen; Shi, Shaocong; Zhang, Weiyi

    2014-11-01

    In this paper, the band-gap and true band-gap are analyzed for the corrugated structures of various types of single wall carbon nanotubes (SWCNTs) within the tight binding approximation. We show that corrugation, combined with curvature effect, yields naturally the true small band-gap in all SWCNTs with small radius. The more stable corrugated structures of SWCNTs are backed by the abinitio total energy calculations for nominally metallic armchair SWCNTs.

  9. Drill pipe protector development

    SciTech Connect

    Thomerson, C.; Kenne, R.; Wemple, R.P.

    1996-03-01

    The Geothermal Drilling Organization (GDO), formed in the early 1980s by the geothermal industry and the U.S. Department of Energy (DOE) Geothermal Division, sponsors specific development projects to advance the technologies used in geothermal exploration, drilling, and production phases. Individual GDO member companies can choose to participate in specific projects that are most beneficial to their industry segment. Sandia National Laboratories is the technical interface and contracting office for the DOE in these projects. Typical projects sponsored in the past have included a high temperature borehole televiewer, drill bits, muds/polymers, rotary head seals, and this project for drill pipe protectors. This report documents the development work of Regal International for high temperature geothermal pipe protectors.

  10. A Multifrequency Notch Filter for Millimeter Wave Plasma Diagnostics based on Photonic Bandgaps in Corrugated Circular Waveguides

    NASA Astrophysics Data System (ADS)

    Wagner, D.; Bongers, W.; Kasparek, W.; Leuterer, F.; Monaco, F.; Münich, M.; Schütz, H.; Stober, J.; Thumm, M.; Brand, H. v. d.

    2015-03-01

    Sensitive millimeter wave diagnostics need often to be protected against unwanted radiation like, for example, stray radiation from high power Electron Cyclotron Heating applied in nuclear fusion plasmas. A notch filter based on a waveguide Bragg reflector (photonic band-gap) may provide several stop bands of defined width within up to two standard waveguide frequency bands. A Bragg reflector that reflects an incident fundamental TE11 into a TM1n mode close to cutoff is combined with two waveguide tapers to fundamental waveguide diameter. Here the fundamental TE11 mode is the only propagating mode at both ends of the reflector. The incident TE11 mode couples through the taper and is converted to the high order TM1n mode by the Bragg structure at the specific Bragg resonances. The TM1n mode is trapped in the oversized waveguide section by the tapers. Once reflected at the input taper it will be converted back into the TE11 mode which then can pass through the taper. Therefore at higher order Bragg resonances, the filter acts as a reflector for the incoming TE11 mode. Outside of the Bragg resonances the TE11 mode can propagate through the oversized waveguide structure with only very small Ohmic attenuation compared to propagating in a fundamental waveguide. Coupling to other modes is negligible in the non-resonant case due to the small corrugation amplitude (typically 0.05·λ0, where λ0 is the free space wavelength). A Bragg reflector for 105 and 140 GHz was optimized by mode matching (scattering matrix) simulations and manufactured by SWISSto12 SA, where the required mechanical accuracy of ± 5 μm could be achieved by stacking stainless steel rings, manufactured by micro-machining, in a high precision guiding pipe. The two smooth-wall tapers were fabricated by electroforming. Several measurements were performed using vector network analyzers from Agilent (E8362B), ABmm (MVNA 8-350) and Rohde&Schwarz (ZVA24) together with frequency multipliers. The stop bands

  11. Heat Pipe Systems

    NASA Astrophysics Data System (ADS)

    1988-01-01

    Solar Fundamentals, Inc.'s hot water system employs space-derived heat pipe technology. It is used by a meat packing plant to heat water for cleaning processing machinery. Unit is complete system with water heater, hot water storage, electrical controls and auxiliary components. Other than fans and a circulating pump, there are no moving parts. System's unique design eliminates problems of balancing, leaking, corroding, and freezing.

  12. Underground pipeline laying using the pipe-in-pipe system

    NASA Astrophysics Data System (ADS)

    Antropova, N.; Krets, V.; Pavlov, M.

    2016-09-01

    The problems of resource saving and environmental safety during the installation and operation of the underwater crossings are always relevant. The paper describes the existing methods of trenchless pipeline technology, the structure of multi-channel pipelines, the types of supporting and guiding systems. The rational design is suggested for the pipe-in-pipe system. The finite element model is presented for the most dangerous sections of the inner pipes, the optimum distance is detected between the roller supports.

  13. Pipe inspection using the pipe crawler. Innovative technology summary report

    SciTech Connect

    1999-05-01

    The US Department of Energy (DOE) continually seeks safer and more cost-effective remediation technologies for use in the decontamination and decommissioning (D and D) of nuclear facilities. In several of the buildings at the Fernald Site, there is piping that was used to transport process materials. As the demolition of these buildings occur, disposal of this piping has become a costly issue. Currently, all process piping is cut into ten-foot or less sections, the ends of the piping are wrapped and taped to prevent the release of any potential contaminants into the air, and the piping is placed in roll off boxes for eventual repackaging and shipment to the Nevada Test Site (NTS) for disposal. Alternatives that allow for the onsite disposal of process piping are greatly desired due to the potential for dramatic savings in current offsite disposal costs. No means is currently employed to allow for the adequate inspection of the interior of piping, and consequently, process piping has been assumed to be internally contaminated and thus routinely disposed of at NTS. The BTX-II system incorporates a high-resolution micro color camera with lightheads, cabling, a monitor, and a video recorder. The complete probe is capable of inspecting pipes with an internal diameter (ID) as small as 1.4 inches. By using readily interchangeable lightheads, the same system is capable of inspecting piping up to 24 inches in ID. The original development of the BTX system was for inspection of boiler tubes and small diameter pipes for build-up, pitting, and corrosion. However, the system is well suited for inspecting the interior of most types of piping and other small, confined areas. The report describes the technology, its performance, uses, cost, regulatory and policy issues, and lessons learned.

  14. Guidable pipe plug

    DOEpatents

    Glassell, Richard L.; Babcock, Scott M.; Lewis, Benjamin E.

    2001-01-01

    A plugging device for closing an opening defined by an end of a pipe with sealant comprises a cap, an extension, an inner seal, a guide, and at least one stop. The cap has an inner surface which defines a chamber adapted for retaining the sealant. The chamber is dimensioned slightly larger than the end so as to receive the end. The chamber and end define a gap therebetween. The extension has a distal end and is attached to the inner surface opposite the distal end. The inner seal is attached to the extension and sized larger than the opening. The guide is positioned forward of the inner seal and attached to the distal end. The guide is also dimensioned to be inserted into the opening. The stop is attached to the extender, and when the stop is disposed in the pipe, the stop is movable with respect to the conduit in one direction and also prevents misalignment of the cap with the pipe. A handle can also be included to allow the cap to be positioned robotically.

  15. Pipe damping studies

    SciTech Connect

    Ware, A.G.

    1986-01-01

    The Idaho National Engineering Laboratory (INEL) is conducting a research program to assist the United States Nuclear Regulatory Commission (USNRC) in determining best-estimate damping values for use in the dynamic analysis of nuclear power plant piping systems. This paper describes four tasks in the program that were undertaken in FY-86. In the first task, tests were conducted on a 5-in. INEL laboratory piping system and data were analyzed from a 6-in. laboratory system at the ANCO Engineers facility to investigate the parameters influencing damping in the seismic frequency range. Further tests were conducted on 3- and 5-in. INEL laboratory piping systems as the second task to determine damping values representative of vibrations in the 33 to 100 Hz range, typical of hydrodynamic transients. In the third task a statistical evaluation of the available damping data was conduted to determine probability distributions suitable for use in probabilistic risk assessments (PRAs), and the final task evaluated damping data at high strain levels.

  16. Heat pipe technology: A bibliography with abstracts

    NASA Technical Reports Server (NTRS)

    1971-01-01

    The annual supplement on heat pipe technology for 1971 is presented. The document contains 101 references with abstracts and 47 patents. The subjects discussed are: (1) heat pipe applications, (2) heat pipe theory, (3) design, development, and fabrication of heat pipes, (4) testing and operation, (5) subject and author index, and (6) heat pipe related patents.

  17. Experimenting with a ``Pipe'' Whistle

    NASA Astrophysics Data System (ADS)

    Stafford, Olga

    2012-04-01

    A simple pipe whistle can be made using pieces of PVC pipe. The whistle can be used to measure the resonant frequencies of open or closed pipes. A slightly modified version of the device can be used to also investigate the interesting dependence of the sound frequencies produced on the orifice-to-edge distance. The pipe whistle described here allows students in a physics of music or introductory physics course to study an example of an "edge tone" device that produces discrete sound frequencies. From their textbooks, students likely know about standing waves produced by pipes or strings, as well as the resonant frequencies for open and closed pipes. To go a bit further, they can also learn how the frequency of the sound wave depends on the orifice-to-edge distance of the wind instrument.

  18. Study of near-source earthquake effects on flexible buried pipes

    NASA Astrophysics Data System (ADS)

    Davis, Craig Alan

    2000-10-01

    An investigation is carried out, using strong ground motion recordings, field measurements, and new analytical models, on large diameter flexible buried pipes shaken in the 1994 Northridge earthquake near field. Case studies are presented for corrugated metal pipes (CMP) in the Van Norman Complex (VNC) vicinity in Los Angeles, California. In 1994 the VNC yielded an unprecedented number of strong motion recordings with high acceleration and velocity. These recordings contain forward directivity pulses and provided the largest velocity ever instrumentally recorded (180 cm/s). The recorded motions were significantly different in the longitudinal and transverse directions and had approximately half the amplitude at the VNC center than on the north and south ends. The seismic performances of 61 underground CMPs are presented, beginning with detailed studies of a 2.4 m diameter pipe that suffered complete lateral buckling collapse at the Lower San Fernando Dam (LSFD). The case histories identify factors controlling large diameter CMP seismic performances that are incorporated into several newly developed models for the analysis and design of buried structures. Each model progressively improves the understanding of buried pipe behavior. Simple acceleration- and strain-based pseudo-static models are initially developed to identify main causes for CMP damage. Elasto-dynamic models for transverse SV waves are later used to understand flexible pipe response in the frequency and time domains and are compared with existing solutions. Finally, pseudo-static models, which analyze pipe responses in terms of free-field strains, are formulated to account for dynamic amplification, non-vertical wave incidence, soil layering, and trench backfill soil stiffness. The elastic models are used to investigate soil-pipe interface shear stress and non-linear soil behavior and show that the maximum pipe hoop force is best characterized by assuming no interface slippage. The models explain the

  19. Insulating Cryogenic Pipes With Frost

    NASA Technical Reports Server (NTRS)

    Stephenson, J. G.; Bova, J. A.

    1985-01-01

    Crystallized water vapor fills voids in pipe insulation. Small, carefully controlled amount of water vapor introduced into dry nitrogen gas before it enters aft fuselage. Vapor freezes on pipes, filling cracks in insulation. Ice prevents gaseous nitrogen from condensing on pipes and dripping on structure, in addition to helping to insulate all parts. Industrial applications include large refrigeration plants or facilities that use cryogenic liquids.

  20. Cryogenic Heat Pipe Experiment (CRYOHP)

    NASA Astrophysics Data System (ADS)

    McIntosh, Roy

    The objective of the CRYOHP experiment is to conduct a shuttle experiment that demonstrates the reliable operation of two oxygen heat pipes in microgravity. The experiment will perform the following tasks: (1) demonstrate startup of the pipes from the supercritical state; (2) measure the heat transport capacity of the pipes; (3) measure evaporator and condenser film coefficients; and (4) work shuttle safety issues. The approach for the experiment is as follows: (1) fly two axially grooved oxygen heat pipes attached to mechanical stirling cycle tactical coolers; (2) integrate experiment in hitch-hiker canister; and (3) fly on shuttle and control from ground.

  1. Thermostructural applications of heat pipes

    NASA Technical Reports Server (NTRS)

    Peeples, M. E.; Reeder, J. C.; Sontag, K. E.

    1979-01-01

    The feasibility of integrating heat pipes in high temperature structure to reduce local hot spot temperature was evaluated for a variety of hypersonic aerospace vehicles. From an initial list of twenty-two potential applications, the single stage to orbit wing leading edge showed the greatest promise and was selected for preliminary design of an integrated heat pipe thermostructural system. The design consisted of a Hastelloy X assembly with sodium heat pipe passages aligned normal to the wing leading edge. A d-shaped heat pipe cross section was determined to be optimum from the standpoint of structural weight.

  2. Cryogenic Heat Pipe Experiment (CRYOHP)

    NASA Technical Reports Server (NTRS)

    Mcintosh, Roy

    1992-01-01

    The objective of the CRYOHP experiment is to conduct a shuttle experiment that demonstrates the reliable operation of two oxygen heat pipes in microgravity. The experiment will perform the following tasks: (1) demonstrate startup of the pipes from the supercritical state; (2) measure the heat transport capacity of the pipes; (3) measure evaporator and condenser film coefficients; and (4) work shuttle safety issues. The approach for the experiment is as follows: (1) fly two axially grooved oxygen heat pipes attached to mechanical stirling cycle tactical coolers; (2) integrate experiment in hitch-hiker canister; and (3) fly on shuttle and control from ground.

  3. Non-binding conductor load bearing roller for a gas-insulated transmission line having a corrugated outer conductor

    DOEpatents

    Fischer, William H.

    1984-01-01

    A gas-insulated transmission line includes a corrugated outer conductor, an inner conductor disposed within and insulated from the outer conductor by means of support insulators and an insulating gas, and a non-binding transport device for supporting and permitting movement of the inner conductor/insulating support assembly axially along the corrugated outer conductor without radial displacement and for moving without binding along corrugations of any slope less than vertical. The transport device includes two movable contacts, such as skids or rollers, supported on a common pivot lever, the pivot lever being rotatably disposed about a pivot lever axis, which pivot lever axis is in turn disposed on the periphery of a support insulator or particle trap if one is used. The movable contacts are separated axially a distance equal to the axial distance between the peaks and valleys of the corrugations of the outer conductor and separated radially a distance equal to the radial distance between the peaks and valleys of the corrugations of the outer conductor. The transport device has the pivot lever axis disposed parallel to the motion of travel of the inner conductor/insulating support assembly.

  4. Non-binding conductor load bearing roller for a gas-insulated transmission line having a corrugated outer conductor

    SciTech Connect

    Fischer, W.H.

    1984-04-24

    A gas-insulated transmission line includes a corrugated outer conductor, an inner conductor disposed within and insulated from the outer conductor by means of support insulators and an insulating gas, and a non-binding transport device for supporting and permitting movement of the inner conductor/insulating support assembly axially along the corrugated outer conductor without radial displacement and for moving without binding along corrugations of any slope less than vertical. The transport device includes two movable contacts, such as skids or rollers, supported on a common pivot lever, the pivot lever being rotatably disposed about a pivot lever axis, which pivot lever axis is in turn disposed on the periphery of a support insulator or particle trap if one is used. The movable contacts are separated axially a distance equal to the axial distance between the peaks and valleys of the corrugations of the outer conductor and separated radially a distance equal to the radial distance between the peaks and valleys of the corrugations of the outer conductor. The transport device has the pivot lever axis disposed parallel to the motion of travel of the inner conductor/insulating support assembly. 7 figs.

  5. Spectral Formulation for the Solution of Full-Wave Scattering from a Conducting Wedge Tipped with a Corrugated Cylinder

    NASA Astrophysics Data System (ADS)

    Polycarpou, A. C.; Christou, M. A.

    2011-11-01

    A spectral mode-matching technique is formulated to solve for the full-wave scattering of a corrugated cylinder-tipped wedge in the presence of an impressed electric or magnetic line source. Asymptotic approximations of large-order Bessel or Henkel functions for a fixed argument were introduced in order to overcome numerical difficulties in their regular series expansions. The corrugations on the conducting cylinder have the shape of annular sectors. The primary objective of this work is to investigate the impact of corrugations on the scattered field in the shadow region of the structure. An optimally designed corrugated cylinder placed at the tip of a conducting wedge can effectively suppress electromagnetic scattering in the shadow region. Obtained numerical results using the proposed approach prove the above concept. These results were validated against numerical data obtained using a nodal finite element method. The aim of this research is to utilize these corrugated tips in horn antenna design for the reduction of side-lobe level and the shaping of the respective E-plane radiation pattern.

  6. Spectral Formulation for the Solution of Full-Wave Scattering from a Conducting Wedge Tipped with a Corrugated Cylinder

    SciTech Connect

    Polycarpou, A. C.; Christou, M. A.

    2011-11-29

    A spectral mode-matching technique is formulated to solve for the full-wave scattering of a corrugated cylinder-tipped wedge in the presence of an impressed electric or magnetic line source. Asymptotic approximations of large-order Bessel or Henkel functions for a fixed argument were introduced in order to overcome numerical difficulties in their regular series expansions. The corrugations on the conducting cylinder have the shape of annular sectors. The primary objective of this work is to investigate the impact of corrugations on the scattered field in the shadow region of the structure. An optimally designed corrugated cylinder placed at the tip of a conducting wedge can effectively suppress electromagnetic scattering in the shadow region. Obtained numerical results using the proposed approach prove the above concept. These results were validated against numerical data obtained using a nodal finite element method. The aim of this research is to utilize these corrugated tips in horn antenna design for the reduction of side-lobe level and the shaping of the respective E-plane radiation pattern.

  7. Spoof surface plasmon modes on doubly corrugated metal surfaces at terahertz frequencies

    NASA Astrophysics Data System (ADS)

    Liu, Yong-Qiang; Kong, Ling-Bao; Du, Chao-Hai; Liu, Pu-Kun

    2016-06-01

    Spoof surface plasmons (SSPs) have many potential applications such as imaging and sensing, communications, innovative leaky wave antenna and many other passive devices in the microwave and terahertz (THz) spectrum. The extraordinary properties of SSPs (e.g. extremely strong near field, enhanced beam–wave interaction) make them especially attractive for developing novel THz electronic sources. SSP modes on doubly corrugated metal surfaces are investigated and analyzed both theoretically and numerically in this paper. The analytical SSP dispersion expressions of symmetric and anti-symmetric modes are obtained with a simplified modal field expansion method; the results are also verified by the finite integration method. Additionally, the propagation losses are also considered for real copper surfaces with a limited constant conductivity in a THz regime. It is shown that the asymptotical frequency of the symmetric mode at the Brillouin boundary decreases along with the decreased gap size between these two corrugated metal surfaces while the asymptotical frequency increases for the anti-symmetric mode. The anti-symmetric mode demonstrates larger propagation losses than the symmetric mode. Further, the losses for both symmetric and anti-symmetric modes decrease when this gap size enlarges. By decreasing groove depth, the asymptotical frequency increases for both the symmetric and the anti-symmetric mode, but the variation of propagation losses is more complicated. Propagation losses increase along with the increased period. Our studies on the dispersion characteristics and propagation losses of SSP modes on this doubly corrugated metallic structure with various parameters is instructive for numerous applications such as waveguides, circuitry systems with high integration, filters and powerful electronic sources in the THz regime.

  8. Deployable Pipe-Z

    NASA Astrophysics Data System (ADS)

    Zawidzki, Machi

    2016-10-01

    This paper presents a concept of deployable Pipe-Z (dPZ): a modular structural system which takes advantage of the robustness of rigid-panel mechanism and allows to create free-form links which are also reconfigurable and deployable. The concept presented can be applied for building habitats and infrastructures for human exploration of oceans and outer space. dPZ structures can adapt to changing requirements e.g. mission objectives, crew condition and technological developments. Furthermore, such lightweight and adaptable structural concept can assist in sustainable exploration development. After brief introduction, the concept of Pipe-Z (PZ) is presented. Next, the reconfigurability of PZ is explained and illustrated with continuous and collision-free transition from a PZ forming a Trefoil knot to a Figure-eight knot. The following sections introduce, explain and illustrate the folding mechanism of a single foldable Pipe-Z module (fPZM) and entire dPZ structure. The latter is illustrated with asynchronous (delayed) unfolding of a relatively complex Unknot. Several applications of PZ are suggested, namely for underwater and deep-space and surface habitats, for permanent, but in particular, temporary or emergency passages. As an example, a scenario of a failure of one of the modules of the International Space Station is presented where a rigid structure of 40 fPZMs bypasses the "dead link". A low-fidelity prototype of a 6-module octagonal dPZ is presented; several folding schemes including concentric toric rings are demonstrated. Practical issues of pressurization and packing are briefly discussed.

  9. Large-bore pipe decontamination

    SciTech Connect

    Ebadian, M.A.

    1998-01-01

    The decontamination and decommissioning (D and D) of 1200 buildings within the US Department of Energy-Office of Environmental Management (DOE-EM) Complex will require the disposition of miles of pipe. The disposition of large-bore pipe, in particular, presents difficulties in the area of decontamination and characterization. The pipe is potentially contaminated internally as well as externally. This situation requires a system capable of decontaminating and characterizing both the inside and outside of the pipe. Current decontamination and characterization systems are not designed for application to this geometry, making the direct disposal of piping systems necessary in many cases. The pipe often creates voids in the disposal cell, which requires the pipe to be cut in half or filled with a grout material. These methods are labor intensive and costly to perform on large volumes of pipe. Direct disposal does not take advantage of recycling, which could provide monetary dividends. To facilitate the decontamination and characterization of large-bore piping and thereby reduce the volume of piping required for disposal, a detailed analysis will be conducted to document the pipe remediation problem set; determine potential technologies to solve this remediation problem set; design and laboratory test potential decontamination and characterization technologies; fabricate a prototype system; provide a cost-benefit analysis of the proposed system; and transfer the technology to industry. This report summarizes the activities performed during fiscal year 1997 and describes the planned activities for fiscal year 1998. Accomplishments for FY97 include the development of the applicable and relevant and appropriate regulations, the screening of decontamination and characterization technologies, and the selection and initial design of the decontamination system.

  10. Heat pipes - Thermal diodes

    NASA Astrophysics Data System (ADS)

    Aptekar, B. F.; Baum, J. M.; Ivanovskii, M. N.; Kolgotin, F. F.; Serbin, V. I.

    The performance concept and peculiarities of the new type of thermal diode with the trap and with the wick breakage are dealt with in the report. The experimental data were obtained and analysed for the working fluid mass and the volume of the liquid in the wick on the forward-mode limiting heat transfer. The flow rate pulsation of the working fluid in the wick was observed visually on the setup with the transparent wall. The quantitative difference on the data on the investigated thermal diode and on the identical heat pipes without the wick breakage is found experimentally concerning the forward-mode limiting heat transfer.

  11. Ceramic heat pipe wick

    NASA Technical Reports Server (NTRS)

    Seidenberg, Benjamin (Inventor); Swanson, Theodore (Inventor)

    1989-01-01

    A wick for use in a capillary loop pump heat pipe is disclosed. The wick material is an essentially uniformly porous, permeable, open-cell, silicon dioxide/aluminum oxide inorganic ceramic foam having a silica fiber ratio, by weight, of about 78 to 22, respectively, a density of 6 lbs/cu ft, and an average pore size of less than 5 microns. A representative material having these characteristics is Lockheed Missile and Space Company, Inc.'s HTP 6-22. This material is fully compatible with the freons and anhydrous ammonia and allows for the use of these very efficient working fluids, and others, in capillary loops.

  12. Removal of Pipe Fouling Inside Pipes Using Ultrasonic Waves

    NASA Astrophysics Data System (ADS)

    Nakagawa, Noritoshi; Fujihara, Masaya; Wu, Chaoqun; Satonobu, Jun

    Since fouling generated inside pipes of chemistry plant equipment, shortens “its life”, periodical maintenance such as cleaning or replacement is needed. Therefore, the development of a safe and sanitary method of preventing a corrosion and blockage inside pipes is desired. In this study, a vibration system, composed of a bolt-clamped Langevin transducer and a pipe, was employed to experimentally study the possibility of fouling removal. In the experiment, a flexural vibration was excited in a pipe containing fouling using ultrasonic waves. When the pipe was made to vibrate, with calcium carbonate or starch used as the fouling, it was shown that the fouling was diffused into the air, and except at the node of the flexural vibration, the fouling was removed completely. Also, the result showed that a higher input voltage to the transducer was more effective in removing the fouling.

  13. Helically corrugated waveguide gyrotron traveling wave amplifier using a thermionic cathode electron gun

    NASA Astrophysics Data System (ADS)

    Cross, A. W.; He, W.; Phelps, A. D. R.; Ronald, K.; Whyte, C. G.; Young, A. R.; Robertson, C. W.; Rafferty, E. G.; Thomson, J.

    2007-06-01

    Experimental operation of a gyrotron traveling wave amplifier with a helically corrugated waveguide using a thermionic cathode electron gun is presented. The coupling between the second harmonic cyclotron mode of the gyrating electron beam and the radiation occurred in the region of near infinite phase velocity over a broad frequency band. With an axis-encircling electron beam of pitch factor of 185keV, and current of 6.0A, the amplifier achieved an output power of 220kW, saturated gain of 24dB, saturated bandwidth of 8.4to10.4GHz, and an interaction efficiency of 20%.

  14. Radiation characteristics of electromagnetic eigenmodes at the corrugated interface of a left-handed material.

    PubMed

    Cuevas, Mauro; Depine, Ricardo A

    2009-08-28

    We study the radiation characteristics of electromagnetic surface waves at a periodically corrugated interface between a conventional and a negatively refracting (or left-handed) material. In this case, and contrary to the surface plasmon polariton in a metallic grating, surface plasmon polaritons may radiate on both sides of the rough interface along which they propagate. We find novel radiation regimes which provide an indirect demonstration of other unusual phenomena characteristic of electromagnetic wave propagation in left-handed materials, such as negative refraction or backward wave propagation.

  15. Analysis of Bonded Joints Between the Facesheet and Flange of Corrugated Composite Panels

    NASA Technical Reports Server (NTRS)

    Yarrington, Phillip W.; Collier, Craig S.; Bednarcyk, Brett A.

    2008-01-01

    This paper outlines a method for the stress analysis of bonded composite corrugated panel facesheet to flange joints. The method relies on the existing HyperSizer Joints software, which analyzes the bonded joint, along with a beam analogy model that provides the necessary boundary loading conditions to the joint analysis. The method is capable of predicting the full multiaxial stress and strain fields within the flange to facesheet joint and thus can determine ply-level margins and evaluate delamination. Results comparing the method to NASTRAN finite element model stress fields are provided illustrating the accuracy of the method.

  16. EDDY CURRENT SYSTEM FOR DETECTION OF CRACKING BENEATH BRAIDING IN CORRUGATED METAL HOSE

    SciTech Connect

    Wincheski, Buzz; Simpson, John; Hall, George

    2009-03-03

    In this paper an eddy current system for the detection of partially-through-the-thickness cracks in corrugated metal hose is presented. Design criteria based upon the geometry and conductivity of the part are developed and applied to the fabrication of a prototype inspection system. Experimental data are used to highlight the capabilities of the system and an image processing technique is presented to improve flaw detection capabilities. A case study for detection of cracking damage in a space shuttle radiator retract flex hoses is also presented.

  17. Eddy Current System for Detection of Cracking Beneath Braiding in Corrugated Metal Hose

    NASA Technical Reports Server (NTRS)

    Wincheski, Buzz; Simpson, John; Hall, George

    2008-01-01

    In this paper an eddy current system for the detection of partially-through-the-thickness cracks in corrugated metal hose is presented. Design criteria based upon the geometry and conductivity of the part are developed and applied to the fabrication of a prototype inspection system. Experimental data are used to highlight the capabilities of the system and an image processing technique is presented to improve flaw detection capabilities. A case study for detection of cracking damage in a space shuttle radiator retract flex hoses is also presented.

  18. Distributed-feedback Terahertz Quantum-cascade Lasers with Laterally Corrugated Metal Waveguides

    NASA Technical Reports Server (NTRS)

    Williams, Benjamin S.; Kumar, Sushil; Hu, Qing; Reno, John L.

    2005-01-01

    We report the demonstration of distributed-feedback terahertz quantum-cascade lasers based on a first-order grating fabricated via a lateral corrugation in a double-sided metal ridge waveguide. The phase of the facet reflection was precisely set by lithographically defined facets by dry etching. Single-mode emission was observed at low to moderate injection currents, although multimode emission was observed far beyond threshold owing to spatial hole burning. Finite-element simulations were used to calculate the modal and threshold characteristics for these devices, with results in good agreement with experiments.

  19. Shear Lag in Corrugated Sheets Used for the Chord Member of a Box Beam

    NASA Technical Reports Server (NTRS)

    Newell, Joseph S; Reissner, Eric

    1941-01-01

    The problem of the distribution of normal stress across a wide corrugated sheet used as the chord of a box-beam-like structure is investigated theoretically and experimentally. Expressions are developed giving the stress distribution in beams, symmetrical or unsymmetrical, about a plane passed spanwise through the center of the sheet. The experiments were arranged to insure bending without torsion and surveys of the normal stresses were made by means of mechanical and electrical strain gages. The experimental data showed very good agreement with the new b of the theoretical curves, especially at the highly stressed sections, for both the symmetrical and unsymmetrical beams. Several suggestions for future research are included.

  20. A study of structurally efficient graphite-thermoplastic trapezoidal-corrugation sandwich and semi-sandwich panels

    NASA Technical Reports Server (NTRS)

    Jegley, Dawn C.

    1993-01-01

    The structural efficiency of compression-loaded trapezoidal-corrugation sandwich and semi-sandwich composite panels is studied to determine their weight savings potential. Sandwich panels with two identical face sheets and a trapezoidal corrugated core between them, and semi-sandwich panels with a corrugation attached to a single skin are considered. An optimization code is used to find the minimum weight designs for critical compressive load levels ranging from 3,000 to 24,000 lb/in. Graphite-thermoplastic panels based on the optimal minimum weight designs were fabricated and tested. A finite-element analysis of several test specimens was also conducted. The results of the optimization study, the finite-element analysis, and the experiments are presented.

  1. Los Alamos National Laboratory corregated metal pipe saw facility preliminary safety analysis report. Volume I

    SciTech Connect

    1990-09-19

    This Preliminary Safety Analysis Report addresses site assessment, facility design and construction, and design operation of the processing systems in the Corrugated Metal Pipe Saw Facility with respect to normal and abnormal conditions. Potential hazards are identified, credible accidents relative to the operation of the facility and the process systems are analyzed, and the consequences of postulated accidents are presented. The risk associated with normal operations, abnormal operations, and natural phenomena are analyzed. The accident analysis presented shows that the impact of the facility will be acceptable for all foreseeable normal and abnormal conditions of operation. Specifically, under normal conditions the facility will have impacts within the limits posted by applicable DOE guidelines, and in accident conditions the facility will similarly meet or exceed the requirements of all applicable standards. 16 figs., 6 tabs.

  2. Alternate high capacity heat pipe

    NASA Technical Reports Server (NTRS)

    Voss, F. E.

    1986-01-01

    The performance predictions for a fifty foot heat pipe (4 foot evaporator - 46 foot condensor) are discussed. These performance predictions are supported by experimental data for a four foot heat pipe. Both heat pipes have evaporators with axial groove wick structures and condensers with powder metal external artery wick structures. The predicted performance of a rectangular axial groove/external artery heat pipe operating in space is given. Heat transport versus groove width is plotted for 100, 200 and 300 grooves in the evaporator. The curves show that maximum power is achieved for groove widths from 0.040 to 0.053 as the number of grooves varies from 300 to 100. The corresponding range of maximum power is 3150 to 2400 watts. The relationships between groove width and heat pipe evaporate diameter for 100, 200 and 300 grooves in the evaporator are given. A four foot heat pipe having a three foot condenser and one foot evaporator was built and tested. The evaporator wick structure used axial grooves with rectangular cross sections, and the condenser wick structure used powder metal with an external artery configuration. Fabrication drawings are enclosed. The predicted and measured performance for this heat pipe is shown. The agreement between predicted and measured performance is good and therefore substantiates the predicted performance for a fifty foot heat pipe.

  3. Building a Copper Pipe "Xylophone."

    ERIC Educational Resources Information Center

    Lapp, David R.

    2003-01-01

    Explains how to use the equation for frequency of vibration of a transversely oscillating bar or pipe with both ends free to vibrate to build a simple and inexpensive xylophone from a 3-meter section of copper pipe. The instrument produces a full major scale and can be used to investigate various musical intervals. (Author/NB)

  4. Demonstrating Sound Impulses in Pipes.

    ERIC Educational Resources Information Center

    Raymer, M. G.; Micklavzina, Stan

    1995-01-01

    Describes a simple, direct method to demonstrate the effects of the boundary conditions on sound impulse reflections in pipes. A graphical display of the results can be made using a pipe, cork, small hammer, microphone, and fast recording electronics. Explains the principles involved. (LZ)

  5. Heat Pipe Blocks Return Flow

    NASA Technical Reports Server (NTRS)

    Eninger, J. E.

    1982-01-01

    Metal-foil reed valve in conventional slab-wick heat pipe limits heat flow to one direction only. With sink warmer than source, reed is forced closed and fluid returns to source side through annular transfer wick. When this occurs, wick slab on sink side of valve dries out and heat pipe ceases to conduct heat.

  6. Pipe crawler with stabilizing midsection

    SciTech Connect

    Zollinger, W.T.; Treanor, R.C.

    1993-09-20

    This invention is comprised of a pipe crawler having a midsection that provides the stability and flexibility to allow the pipe crawler to negotiate curved and uneven segments of piping while traveling through piping systems. The pipe crawler comprises a front leg assembly, a rear leg assembly, a midsection with a gimbal at each end for connecting the midsection to the front and rear leg assemblies in a flexible manner, and an air cylinder for changing the distance between the front and rear leg assemblies. The pipe crawler moves in ``inch worm`` fashion with the front and rear leg assemblies alternating between an extended and a retracted position as the air cylinder moves the retracted leg assembly forward. The midsection has a plurality of legs extending radially for holding the midsection within a maximum displacement from the piping axis so that the gimbals are not pivoted to extreme angles where they might lock up or seize. When the midsection is displaced sufficiently, its legs with wheels on each end engage the interior surface of the piping and prevent further displacement. Using two gimbals divides the angle between the planes defined by the front and rear leg assemblies which also helps to prevent excessive gimbal pivoting.

  7. Pipe crawler with stabilizing midsection

    DOEpatents

    Zollinger, William T.; Treanor, Richard C.

    1994-01-01

    A pipe crawler having a midsection that provides the stability and flexibty to allow the pipe crawler to negotiate curved and uneven segments of piping while traveling through piping systems. The pipe crawler comprises a front leg assembly, a rear leg assembly, a midsection with a gimbal at each end for connecting the midsection to the front and rear leg assemblies in a flexible manner, and an air cylinder for changing the distance between the front and rear leg assemblies. The pipe crawler moves in "inch worm" fashion with the front and rear leg assemblies alternating between an extended and a retracted position as the air cylinder moves the retracted leg assembly forward. The midsection has a plurality of legs extending radially for holding the midsection within a maximum displacement from the piping axis so that the gimbals are not pivoted to extreme angles where they might lock up or seize. When the midsection is displaced sufficiently, its legs with wheels on each end engage the interior surface of the piping and prevent further displacement. Using two gimbals divides the angle between the planes defined by the front and rear leg assemblies which also helps to prevent excessive gimbal pivoting.

  8. Pipe crawler with stabilizing midsection

    DOEpatents

    Zollinger, W.T.; Treanor, R.C.

    1994-12-27

    A pipe crawler is described having a midsection that provides the stability and flexibility to allow the pipe crawler to negotiate curved and uneven segments of piping while traveling through piping systems. The pipe crawler comprises a front leg assembly, a rear leg assembly, a midsection with a gimbal at each end for connecting the midsection to the front and rear leg assemblies in a flexible manner, and an air cylinder for changing the distance between the front and rear leg assemblies. The pipe crawler moves in ''inch worm'' fashion with the front and rear leg assemblies alternating between an extended and a retracted position as the air cylinder moves the retracted leg assembly forward. The midsection has a plurality of legs extending radially for holding the midsection within a maximum displacement from the piping axis so that the gimbals are not pivoted to extreme angles where they might lock up or seize. When the midsection is displaced sufficiently, its legs with wheels on each end engage the interior surface of the piping and prevent further displacement. Using two gimbals divides the angle between the planes defined by the front and rear leg assemblies which also helps to prevent excessive gimbal pivoting. 5 figures.

  9. Vapor spill pipe monitor

    NASA Astrophysics Data System (ADS)

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

    1983-06-01

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

  10. Vapor spill pipe monitor

    DOEpatents

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

    1983-06-23

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

  11. Vibration analysis methods for piping

    NASA Astrophysics Data System (ADS)

    Gibert, R. J.

    1981-09-01

    Attention is given to flow vibrations in pipe flow induced by singularity points in the piping system. The types of pressure fluctuations induced by flow singularities are examined, including the intense wideband fluctuations immediately downstream of the singularity and the acoustic fluctuations encountered in the remainder of the circuit, and a theory of noise generation by unsteady flow in internal acoustics is developed. The response of the piping systems to the pressure fluctuations thus generated is considered, and the calculation of the modal characteristics of piping containing a dense fluid in order to obtain the system transfer function is discussed. The TEDEL program, which calculates the vibratory response of a structure composed of straight and curved pipes with variable mechanical characteristics forming a three-dimensional network by a finite element method, is then presented, and calculations of fluid-structural coupling in tubular networks are illustrated.

  12. Flexible ultrasonic pipe inspection apparatus

    SciTech Connect

    Jenkins, Charles F.; Howard, Boyd D.

    1998-01-01

    A flexible, modular ultrasonic pipe inspection apparatus, comprising a flexible, hollow shaft that carries a plurality of modules, including at least one rotatable ultrasonic transducer, a motor/gear unit, and a position/signal encoder. The modules are connected by flexible knuckle joints that allow each module of the apparatus to change its relative orientation with respect to a neighboring module, while the shaft protects electrical wiring from kinking or buckling while the apparatus moves around a tight corner. The apparatus is moved through a pipe by any suitable means, including a tether or drawstring attached to the nose or tail, differential hydraulic pressure, or a pipe pig. The rotational speed of the ultrasonic transducer and the forward velocity of the apparatus are coordinated so that the beam sweeps out the entire interior surface of the pipe, enabling the operator to accurately assess the condition of the pipe wall and determine whether or not leak-prone corrosion damage is present.

  13. Prometheus Hot Leg Piping Concept

    SciTech Connect

    Gribik, Anastasia M.; DiLorenzo, Peter A.

    2007-01-30

    The Naval Reactors Prime Contractor Team (NRPCT) recommended the development of a gas cooled reactor directly coupled to a Brayton energy conversion system as the Space Nuclear Power Plant (SNPP) for NASA's Project Prometheus. The section of piping between the reactor outlet and turbine inlet, designated as the hot leg piping, required unique design features to allow the use of a nickel superalloy rather than a refractory metal as the pressure boundary. The NRPCT evaluated a variety of hot leg piping concepts for performance relative to SNPP system parameters, manufacturability, material considerations, and comparison to past high temperature gas reactor (HTGR) practice. Manufacturability challenges and the impact of pressure drop and turbine entrance temperature reduction on cycle efficiency were discriminators between the piping concepts. This paper summarizes the NRPCT hot leg piping evaluation, presents the concept recommended, and summarizes developmental issues for the recommended concept.

  14. Promethus Hot Leg Piping Concept

    SciTech Connect

    AM Girbik; PA Dilorenzo

    2006-01-24

    The Naval Reactors Prime Contractor Team (NRPCT) recommended the development of a gas cooled reactor directly coupled to a Brayton energy conversion system as the Space Nuclear Power Plant (SNPP) for NASA's Project Prometheus. The section of piping between the reactor outlet and turbine inlet, designated as the hot leg piping, required unique design features to allow the use of a nickel superalloy rather than a refractory metal as the pressure boundary. The NRPCT evaluated a variety of hot leg piping concepts for performance relative to SNPP system parameters, manufacturability, material considerations, and comparison to past high temperature gas reactor (HTGR) practice. Manufacturability challenges and the impact of pressure drop and turbine entrance temperature reduction on cycle efficiency were discriminators between the piping concepts. This paper summarizes the NRPCT hot leg piping evaluation, presents the concept recommended, and summarizes developmental issues for the recommended concept.

  15. Seismic piping test and analysis

    SciTech Connect

    Not Available

    1980-09-01

    This report presents selected results to date of a dynamic testing and analysis program focusing on a piping system at Consolidated Edison Company of New York's Indian Point-1 Nuclear Generating Station. The goal of this research program is the development of more accurate and realistic models of piping systems subjected to seismic, hydraulic, operating, and other dynamic loads. The program seeks to identify piping system properties significant to dynamic response rather than seeking to simulate any particular form of excitation. The fundamental experimental approach is the excitation of piping/restraint devices/supports by a variety of dynamic test methods and the analysis of the resulting response to identify the characteristic dynamic properties of the system tested. The comparison of the identified dynamic properties to those predicted by alternative analytical approaches will support improvements in methods used in the dynamic analysis of piping, restraint, devices, and supports.

  16. Advances in pipe prover technology

    SciTech Connect

    Jakubenas, P.P.

    1996-09-01

    The petroleum industry has used pipe provers for on line calibration of liquid flow meters for over 30 years. Recently a number of innovations have come to the forefront that enhance the reliability of pipe provers, reduce their size, make them more accurate, and increase their value to the end users. With the widespread use of turbine meters for custody transfer, accurate measurement is more dependent on frequent proving, thus the industry will continue to demand advanced provers and proving techniques. The author will discuss the aforementioned subject with regard to both bidirectional and unidirectional pipe provers. A description of the operational principles of pipe provers and the enhancements that are now available in terms of prover mechanical configuration and electronic instrumentation will be described in detail. In addition, information will be provided concerning integration of pipe provers into measurement systems and design and use of sophisticated computer control systems for automated proving.

  17. D0 Silicon Upgrade: Upgrade Piping Loads on Cleanroom Roof

    SciTech Connect

    Sakla, Steve; /Fermilab

    1995-08-28

    The proposed piping layout for the DO upgrade will run along the south wall of DAB. The cryogenic service pipe runs above the upper and lower cleanroom roofs and will need to be supported by the roofs beams. Calculations were done to determine the stresses in the I-beams created by the existing and additional loads due to the upgrade. Refer to drawing no. 3823.115-ME-317283 for drawings of the piping layout. Figure 1 shows the 'plan view' portion of this drawing. The weight of the individual lines were calculated in figure 2 assuming a pipe density of O.28 lbm/in{sup 3} for stainless steel (0.12% C) and a fluid density (assuming LN2 at 1 atm) of 0.03 lbm/in{sup 3}. The weights of the corrugated steel flooring, assembly hall feed cans, support beams, and roof hatch were also included in the analysis. These loads are calculated on pgs. 5-6. A floor load of 50 lbf/ft{sup 2} was also added in order to maintain the existing floor load limit in addition to the added piping loads. Measurements of the dimensions of the I-beams determined that the nominal sizes of the beams were W8 x 21 for the lower roof and W14 x 26 for the upper roof. Pipe lengths were determined from the drawing for each of the lines on pgs. 1-2 of the calculations (refer to all piping by line numbers according to figure 2). A total weight was calculated for lines 3-9 along the south wall and lines 1-2 running along the north wall of the lower cleanroom roof. To simplify the calculations these weights were assumed to be evenly distributed on the 5 I-beam supports of the lower cleanroom roof 2.5 feet in from the south wall. The stress analysis was done using FrameMac, a 2-D finite element program for the Macintosh. Beam 3 was not included in the analysis because it is structurally equivalent to beam 1. The program outputted maximum values for shear stress, bending stress, shear force, and moments in each of the beams analyzed. These values were then compared to the allowable stresses as per the

  18. Technology for concrete pipe manipulator

    NASA Astrophysics Data System (ADS)

    Li, Bin; Wang, Dan; Lin, Renzhi

    2010-01-01

    The pipe manipulator is a developing mechatronic system to enhance productivity and protects workers from cave-ins in the trench while excavating and laying pipe. The pipe manipulator is for installing concrete pipe into the trench. It is an optical-electro-mechanical system. The mechanism is make up of two parts, the upside and underside. The upside is for lifting the equipment by backhoe and rotating the underside mechanism. It includes rigidity lift beams, holding pad, four-bar linkages, hydraulic cylinder, rotating support, and rotating mechanism. Holding pad will press the bucket back to keep the bucket hooking the pipe man safely and stably. The underside mechanism is for lifting, holding and adjusting the pipe section's stance. The underside mechanism includes support trolley, and lift fork. The support trolley is driven by hydraulic cylinder for moving the fork forward or backward while laying a pipe into trench. The fork is with a self-lock mechanism for preventing the pipe from slide out of the prongs. A new photoelectric locating system is developed for auto-measuring the installing pipe section's stance within the work area. The laser target has been developed as a key part in the photoelectric locating systems. The photoelectric target is a rotating polar coordinate. Photodiodes are used for making the polar radius. There is an angular displacement sensor sitting on the heart-axis of the target for measuring angle of the target rotating. The pipe manipulator can be located by the system, and the locating methods have been presented at last of the paper.

  19. Technology for concrete pipe manipulator

    NASA Astrophysics Data System (ADS)

    Li, Bin; Wang, Dan; Lin, Renzhi

    2009-12-01

    The pipe manipulator is a developing mechatronic system to enhance productivity and protects workers from cave-ins in the trench while excavating and laying pipe. The pipe manipulator is for installing concrete pipe into the trench. It is an optical-electro-mechanical system. The mechanism is make up of two parts, the upside and underside. The upside is for lifting the equipment by backhoe and rotating the underside mechanism. It includes rigidity lift beams, holding pad, four-bar linkages, hydraulic cylinder, rotating support, and rotating mechanism. Holding pad will press the bucket back to keep the bucket hooking the pipe man safely and stably. The underside mechanism is for lifting, holding and adjusting the pipe section's stance. The underside mechanism includes support trolley, and lift fork. The support trolley is driven by hydraulic cylinder for moving the fork forward or backward while laying a pipe into trench. The fork is with a self-lock mechanism for preventing the pipe from slide out of the prongs. A new photoelectric locating system is developed for auto-measuring the installing pipe section's stance within the work area. The laser target has been developed as a key part in the photoelectric locating systems. The photoelectric target is a rotating polar coordinate. Photodiodes are used for making the polar radius. There is an angular displacement sensor sitting on the heart-axis of the target for measuring angle of the target rotating. The pipe manipulator can be located by the system, and the locating methods have been presented at last of the paper.

  20. Transmission Loss and Absorption of Corrugated Core Sandwich Panels With Embedded Resonators

    NASA Technical Reports Server (NTRS)

    Allen, Albert R.; Schiller, Noah H.; Zalewski, Bart F.; Rosenthal, Bruce N.

    2014-01-01

    The effect of embedded resonators on the diffuse field sound transmission loss and absorption of composite corrugated core sandwich panels has been evaluated experimentally. Two 1.219 m × 2.438 m panels with embedded resonator arrangements targeting frequencies near 100 Hz were evaluated using non-standard processing of ASTM E90-09 acoustic transmission loss and ASTM C423-09a room absorption test measurements. Each panel is comprised of two composite face sheets sandwiching a corrugated core with a trapezoidal cross section. When inlet openings are introduced in one face sheet, the chambers within the core can be used as embedded acoustic resonators. Changes to the inlet and chamber partition locations allow this type of structure to be tuned for targeted spectrum passive noise control. Because the core chambers are aligned with the plane of the panel, the resonators can be tuned for low frequencies without compromising the sandwich panel construction, which is typically sized to meet static load requirements. Absorption and transmission loss performance improvements attributed to opening the inlets were apparent for some configurations and inconclusive for others.

  1. Inkjet printing of UHF antennas on corrugated cardboards for packaging applications

    NASA Astrophysics Data System (ADS)

    Sowade, Enrico; Göthel, Frank; Zichner, Ralf; Baumann, Reinhard R.

    2015-03-01

    In this study, a method based on inkjet printing has been established to develop UHF antennas on a corrugated cardboard for packaging applications. The use of such a standardized, paper-based packaging substrate as material for printing electronics is challenging in terms of its high surface roughness and high ink absorption rate, especially when depositing very thin films with inkjet printing technology. However, we could obtain well-defined silver layers on the cardboard substrates due to a primer layer approach. The primer layer is based on a UV-curable ink formulation and deposited as well as the silver ink with inkjet printing technology. Industrial relevant printheads were chosen for the deposition of the materials. The usage of inkjet printing allows highest flexibility in terms of pattern design. The primer layer was proven to optimize the surface characteristics of the substrate, mainly reducing the surface roughness and water absorptiveness. Thanks to the primer layer approach, ultra-high-frequency (UHF) radio-frequency identification (RFID) antennas were deposited by inkjet printing on the corrugated cardboards. Along with the characterization and interpretation of electrical properties of the established conductive antenna patterns, the performance of the printed antennas were analyzed in detail by measuring the scattering parameter S11 and the antenna gain.

  2. Investigation of a corrugated channel flow with an open source PIV software

    NASA Astrophysics Data System (ADS)

    Sivas, Deniz; Bahadır Olcay, A.; Ahn, Hojin

    2016-03-01

    In this study, the corrugated channel flow was investigated by using an open-source particle image velocimetry (PIV) software. The open-source software called OpenPIV was first verified by using images of an earlier experimental work of a vortex ring formation. The corrugated channel flow images were taken with 200 W power LED light source and a high speed camera and those images were analysed with these spatial and temporal tools of OpenPIV. Laminar, transient and turbulent flow regimes were identified when Reynolds number was below 1100, in between 1100 and 2000 and higher than 2000, respectively. The velocity vectors were found to be about 20% lower than the previous study results. The flow inside the grooves was also investigated with OpenPIV and flow characteristics at the grooves were captured when interrogation window size was lowered. The visualization of the flow was presented for different Reynolds numbers with the relative scale values. As a result of this study, OpenPIV software was determined as promising open source PIV analysis software.

  3. Study of the effects of corrugated wall structures due to blanket modules around ICRH antennas

    SciTech Connect

    Dumortier, Pierre; Louche, Fabrice; Messiaen, André; Vervier, Michel

    2014-02-12

    In future fusion reactors, and in ITER, the first wall will be covered by blanket modules. These blanket modules, whose dimensions are of the order of the ICRF wavelengths, together with the clearance gaps between them will constitute a corrugated structure which will interact with the electromagnetic waves launched by ICRF antennas. The conditions in which the grooves constituted by the clearance gaps between the blanket modules can become resonant are studied. Simple analytical models and numerical simulations show that mushroom type structures (with larger gaps at the back than at the front) can bring down the resonance frequencies, which could lead to large voltages in the gaps between the blanket modules and perturb the RF properties of the antenna if they are in the ICRF operating range. The effect on the wave propagation along the wall structure, which is acting as a spatially periodic (toroidally and poloidally) corrugated structure, and hence constitutes a slow wave structure modifying the wall boundary condition, is examined.

  4. Atomic-scale friction modulated by potential corrugation in multi-layered graphene materials

    NASA Astrophysics Data System (ADS)

    Zhuang, Chunqiang; Liu, Lei

    2015-03-01

    Friction is an important issue that has to be carefully treated for the fabrication of graphene-based nano-scale devices. So far, the friction mechanism of graphene materials on the atomic scale has not yet been clearly presented. Here, first-principles calculations were employed to unveil the friction behaviors and their atomic-scale mechanism. We found that potential corrugations on sliding surfaces dominate the friction force and the friction anisotropy of graphene materials. Higher friction forces correspond to larger corrugations of potential energy, which are tuned by the number of graphene layers. The friction anisotropy is determined by the regular distributions of potential energy. The sliding along a fold-line path (hollow-atop-hollow) has a relatively small potential energy barrier. Thus, the linear sliding observed in macroscopic friction experiments may probably be attributed to the fold-line sliding mode on the atomic scale. These findings can also be extended to other layer-structure materials, such as molybdenum disulfide (MoS2) and graphene-like BN sheets.

  5. High-efficiency wideband gyro-TWTs and gyro-BWOs with helically corrugated waveguides

    NASA Astrophysics Data System (ADS)

    Bratman, V. L.; Denisov, G. G.; Samsonov, S. V.; Cross, A. W.; Phelps, A. D. R.; Xe, W.

    2007-02-01

    We review the studies of gyrotron-type microwave devices whose electrodynamic system has the form of an oversized metal waveguide with a helically corrugated internal surface. For certain parameters, such a corrugation changes radically the waveguide dispersion ensuring an almost constant group velocity of the eigenmode for a small (close to zero) longitudinal wave number in a wide frequency band. The use of “helical” waveguides along with electron optical systems which form near-axis electron beams makes it possible to create high-efficiency amplifiers based on gyro-traveling-wave tubes (gyro-TWTs) with a wide instantaneous frequency band of amplification and gyro-backward-wave oscillators (gyro-BWOs) with continuous wideband tuning of the oscillation frequency. The studied devices are superior to the well-studied microwave sources of this type (gyroklystrons and gyrotrons) in frequency band, by more than an order of magnitude, and are not inferior to them in efficiency even for a wide spread of electron velocities.

  6. Experimental demonstration of a high-power slow wave electron cyclotron maser utilizing corrugated metal structure

    SciTech Connect

    Minami, K.; Ogura, K.; Kurashina, K; Kim, W.; Watanabe, Tsuguhiro; Carmel, Y.; Destler, W.W.; Granatstein, V.L.

    1994-12-31

    High-power microwave (HPM) sources based on electron cyclotron resonance (ECR) such as gyrotrons are fast wave devices and velocity component of electron beam perpendicular to guiding magnetic field is the origin of HPM. HPM sources based on Cherenkove mechanism are slow wave devices and can be driven by a beam without initial perpendicular velocity. The authors present here the experimental result that seems to be the first demonstration of high-power slow wave electron cyclotron maser (ECM) consisting of a large diameter sinusoidally corrugated metal waveguide driven by a beam with predominant parallel velocity. The designed size parameters of slow wave structure (SWS) are as follows: average radius 30 mm, corrugation pitch 3.4 mm, its amplitude h = 1.7 mm and total length 238 mm. They use an annular beam with radius 26.3 mm, energy 55 keV, current 200 A in their experiment. Expected Cherenkov oscillation frequency of TM01 mode is 20 GHz. The observed high-power microwaves can be quantitatively explained by a backward wave oscillation with Cherenkov mechanism enhanced by positive feedback of anomalous Doppler slow cyclotron wave. In conclusion, the slow wave ECM presented here will be a competitive candidate against gyrotrons for generating multi-MW millimeter microwaves available in fusion plasma research.

  7. Atomic-scale friction modulated by potential corrugation in multi-layered graphene materials

    SciTech Connect

    Zhuang, Chunqiang; Liu, Lei

    2015-03-21

    Friction is an important issue that has to be carefully treated for the fabrication of graphene-based nano-scale devices. So far, the friction mechanism of graphene materials on the atomic scale has not yet been clearly presented. Here, first-principles calculations were employed to unveil the friction behaviors and their atomic-scale mechanism. We found that potential corrugations on sliding surfaces dominate the friction force and the friction anisotropy of graphene materials. Higher friction forces correspond to larger corrugations of potential energy, which are tuned by the number of graphene layers. The friction anisotropy is determined by the regular distributions of potential energy. The sliding along a fold-line path (hollow-atop-hollow) has a relatively small potential energy barrier. Thus, the linear sliding observed in macroscopic friction experiments may probably be attributed to the fold-line sliding mode on the atomic scale. These findings can also be extended to other layer-structure materials, such as molybdenum disulfide (MoS{sub 2}) and graphene-like BN sheets.

  8. Energy corrugation in atomic-scale friction on graphite revisited by molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Sun, Xiao-Yu; Qi, Yi-Zhou; Ouyang, Wengen; Feng, Xi-Qiao; Li, Qunyang

    2016-08-01

    Although atomic stick-slip friction has been extensively studied since its first demonstration on graphite, the physical understanding of this dissipation-dominated phenomenon is still very limited. In this work, we perform molecular dynamics (MD) simulations to study the frictional behavior of a diamond tip sliding over a graphite surface. In contrast to the common wisdom, our MD results suggest that the energy barrier associated lateral sliding (known as energy corrugation) comes not only from interaction between the tip and the top layer of graphite but also from interactions among the deformed atomic layers of graphite. Due to the competition of these two subentries, friction on graphite can be tuned by controlling the relative adhesion of different interfaces. For relatively low tip-graphite adhesion, friction behaves normally and increases with increasing normal load. However, for relatively high tip-graphite adhesion, friction increases unusually with decreasing normal load leading to an effectively negative coefficient of friction, which is consistent with the recent experimental observations on chemically modified graphite. Our results provide a new insight into the physical origins of energy corrugation in atomic scale friction.

  9. Radiation patterns of multi-moded corrugated horns for far-IR space applications

    NASA Astrophysics Data System (ADS)

    Murphy, J. Anthony; Colgan, Ruth; O'Sullivan, Creidhe; Maffei, Bruno; Ade, Peter

    2001-12-01

    Multi-moded horn antennas are now being proposed for far-IR space imaging systems in which diffraction limited resolution is not required (e.g. the High-Frequency Instrument (HFI) on the ESA PLANCK Surveyor). In such systems individual modes in the waveguide filter section feeding the horn can couple independently to an overmoded detector (such as a bolometer in an integrating cavity). The number of modes is chosen to optimize the coupling efficiency to the source without compromising any spillover losses. We consider in detail the case of a cylindrically symmetric corrugated configuration, presenting two alternative techniques for modelling such few-moded systems. The first approach is based on a mode-matching description of propagation in a non-uniform waveguide structure, while the second approach makes use of hybrid mode solutions for a waveguide with corrugated walls assuming a uniform but non-isotropic impedance. We present practical examples comparing the radiation patterns predicted by both models.

  10. Simple Expressions for the Design of Linear Tapers in Overmoded Corrugated Waveguides

    PubMed Central

    Schaub, S. C.; Shapiro, M. A.; Temkin, R. J.

    2016-01-01

    Simple analytical formulae are presented for the design of linear tapers with very low mode conversion loss in overmoded corrugated waveguides. For tapers from waveguide radius a2 to a1, with a1 < a2, the optimal length of the taper is 3.198a1a2/λ. Here, λ is the wavelength of radiation. The fractional loss of the HE11 mode in an optimized taper is 0.0293(a2−a1)4∕a12a22. These formulae are accurate when a2 ≲ 2a1. Slightly more complex formulae, accurate for a2 ≤ 4a1, are also presented in this paper. The loss in an overmoded corrugated linear taper is less than 1 % when a2 ≤ 2.12a1 and less than 0.1 % when a2 ≤ 1.53a1. The present analytic results have been benchmarked against a rigorous mode matching code and have been found to be very accurate. The results for linear tapers are compared with the analogous expressions for parabolic tapers. Parabolic tapers may provide lower loss, but linear tapers with moderate values of a2/a1 may be attractive because of their simplicity of fabrication. PMID:27053963

  11. Beam Mode Expansion of Corrugated Conical Horns with Phase Correcting Lens: Application to Radioastronomy Receivers

    NASA Astrophysics Data System (ADS)

    García, E.; de Haro, L.; O'Sullivan, C.; Cahill, G.; López Fernández, J. A.; Tercero, F.; Galocha, B.; Besada, J. L.

    2003-06-01

    A classical radioastronomy receiver is fed with a corrugated horn and an independent lens, both placed in a cryostat to lower the noise temperature. The beam is focused and directed using a combination of elliptical and plane mirrors. This paper proposes modifying the initial feeding system by placing the lens onto the horn aperture, thereby allowing a size reduction of the horn and lens, and a simplification of their mechanical design. The profiled lens is shaped to correct the phase error on the horn aperture. A quasi-optical model of the horn-plus-lens system has been developed using a Beam Mode Expansion (BME). Results using both a hyperbolic-planar lens and a spherical-elliptical lens, as well as results obtained by using Geometrical Optics (GO) with a Kirchoff Huygens integration to get the far-field pattern, have been compared with measurements. As a direct application, a full focusing system for the new 40-m radiotelescope at the “Centro Astronómico de Yebes” is presented for the 22, 30 and 45 GHz bands. This paper has developed a QO model for a corrugated conical horn with a phase-correcting lens.

  12. Corrugation of Phase-Separated Lipid Bilayers Supported by Nanoporous Silica Xerogel Surfaces

    SciTech Connect

    Goksu, E I; Nellis, B A; Lin, W; Satcher Jr., J H; Groves, J T; Risbud, S H; Longo, M L

    2008-10-30

    Lipid bilayers supported by substrates with nanometer-scale surface corrugations holds interest in understanding both nanoparticle-membrane interactions and the challenges of constructing models of cell membranes on surfaces with desirable properties, e.g. porosity. Here, we successfully form a two-phase (gel-fluid) lipid bilayer supported by nanoporous silica xerogel. Surface topology, diffusion, and lipid density in comparison to mica-supported lipid bilayers were characterized by AFM, FRAP, FCS, and quantitative fluorescence microscopy, respectively. We found that the two-phase lipid bilayer follows the xerogel surface contours. The corrugation imparted on the lipid bilayer results in a lipid density that is twice that on a flat mica surface. In direct agreement with the doubling of actual bilayer area in a projected area, we find that the lateral diffusion coefficient (D) of lipids on xerogel ({approx}1.7 {micro}m{sup 2}/s) is predictably lower than on mica ({approx}4.1 {micro}m{sup 2}/s) by both FRAP and FCS techniques. Furthermore, the gel-phase domains on xerogel compared to mica were larger and less numerous. Overall, our results suggest the presence of a relatively defect-free continuous two-phase bilayer that penetrates approximately midway into the first layer of {approx}50 nm xerogel beads.

  13. Simple Correctors for Elimination of High-Order Modes in Corrugated Waveguide Transmission Lines

    PubMed Central

    Kowalski, Elizabeth J.; Shapiro, Michael A.; Temkin, Richard J.

    2014-01-01

    When using overmoded corrugated waveguide transmission lines for high power applications, it is necessary to control the mode content of the system. Ideally, overmoded corrugated transmission lines operate in the fundamental HE11 mode and provide low losses for long distances. Unwanted higher order modes (HOMs), particularly LP11 and HE12, are often excited in the experimental systems due to practical misalignments in the transmission line system. This paper discusses how the unwanted modes propagate along with the fundamental mode in the transmission line system by formulating an equation that relates the center of power offset and angle of propagation of a beam (for the HE11 and LP11 modes) or the waist size and phase front radius of curvature of a beam (for the HE11 and HE12 modes). By introducing two miter bend correctors into the transmission system—miter bends that have slightly angled or ellipsoidal mirrors—the HOMs can be precisely manipulated in the system. This technique can be used to eliminate small quantities of unwanted modes, thereby creating a nearly pure fundamental mode beam with minimal losses. Examples of these applications are calculated and show the theoretical conversion of up to 10% HOM content into the fundamental HE11 mode with minimal losses. PMID:25067859

  14. Sound Transmission at Pipe Joints.

    NASA Astrophysics Data System (ADS)

    Servis, Dimitris C.

    Available from UMI in association with The British Library. A model was developed using beam and plane wave theory to describe the sound transmission at pipe joints. This approach greatly simplifies the modelling of the pipe joint and the solution is presented in a manner which can be applied in both the Frequency and the Time domain, for the solution of acoustic and fluid dynamics problems related to pipe joint transmission. This form of modelling can be extended to describe a wide range of pipe joints and discontinuities and lend itself to the study of piping networks by incorporating its solution in existing models used to describe the performance of large systems. A variety of experimental techniques have been explored and applied for the measurement of the sound transmission at pipe joints. The model predictions were found to be in good agreement with experimental data and form the basis of a simple and effective method for the study of sound transmission at pipe joints.

  15. Plastic pipe insertion

    SciTech Connect

    Diskin, J.

    1987-05-01

    In March 1987 KPL changed all that when the utility inserted 1,000 ft of 16-in. SDR 15.5 Phillips Driscopipe 8000 pipe with a wall thickness of 1.032-in., into an abandoned 24-in. cast-iron line in downtown Kansas City. This is believed to be the largest diameter insert removal job ever done for gas distribution in the U.S. For KPL it was a natural progression from the smaller sizes used earlier. The procedure is the same, and the operation was quick and comparatively simple. Lower construction costs were the bottom line because with insert renewal there is no need to cut up the streets, a major expense in any urban pipeline work. There are other significant costs savings as well because the insert renewal construction process is faster than other techniques.

  16. 46 CFR 45.133 - Air pipes.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Air pipes. 45.133 Section 45.133 Shipping COAST GUARD....133 Air pipes. (a) Where an air pipe to any tank extends above the freeboard or superstructure deck— (1) The exposed part of the air pipe must be made of steel and of sufficient thickness to...

  17. 46 CFR 45.133 - Air pipes.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Air pipes. 45.133 Section 45.133 Shipping COAST GUARD....133 Air pipes. (a) Where an air pipe to any tank extends above the freeboard or superstructure deck— (1) The exposed part of the air pipe must be made of steel and of sufficient thickness to...

  18. 46 CFR 45.133 - Air pipes.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Air pipes. 45.133 Section 45.133 Shipping COAST GUARD....133 Air pipes. (a) Where an air pipe to any tank extends above the freeboard or superstructure deck— (1) The exposed part of the air pipe must be made of steel and of sufficient thickness to...

  19. 46 CFR 45.133 - Air pipes.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Air pipes. 45.133 Section 45.133 Shipping COAST GUARD....133 Air pipes. (a) Where an air pipe to any tank extends above the freeboard or superstructure deck— (1) The exposed part of the air pipe must be made of steel and of sufficient thickness to...

  20. 49 CFR 192.281 - Plastic pipe.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Plastic pipe. 192.281 Section 192.281... Plastic pipe. (a) General. A plastic pipe joint that is joined by solvent cement, adhesive, or heat fusion may not be disturbed until it has properly set. Plastic pipe may not be joined by a threaded joint...

  1. 49 CFR 192.281 - Plastic pipe.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Plastic pipe. 192.281 Section 192.281... Plastic pipe. (a) General. A plastic pipe joint that is joined by solvent cement, adhesive, or heat fusion may not be disturbed until it has properly set. Plastic pipe may not be joined by a threaded joint...

  2. 49 CFR 192.281 - Plastic pipe.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Plastic pipe. 192.281 Section 192.281... Plastic pipe. (a) General. A plastic pipe joint that is joined by solvent cement, adhesive, or heat fusion may not be disturbed until it has properly set. Plastic pipe may not be joined by a threaded joint...

  3. 49 CFR 192.281 - Plastic pipe.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Plastic pipe. 192.281 Section 192.281... Plastic pipe. (a) General. A plastic pipe joint that is joined by solvent cement, adhesive, or heat fusion may not be disturbed until it has properly set. Plastic pipe may not be joined by a threaded joint...

  4. 49 CFR 192.281 - Plastic pipe.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Plastic pipe. 192.281 Section 192.281... Plastic pipe. (a) General. A plastic pipe joint that is joined by solvent cement, adhesive, or heat fusion may not be disturbed until it has properly set. Plastic pipe may not be joined by a threaded joint...

  5. 49 CFR 192.279 - Copper pipe.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Copper pipe. 192.279 Section 192.279 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... Copper pipe. Copper pipe may not be threaded except that copper pipe used for joining screw fittings...

  6. 49 CFR 192.279 - Copper pipe.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Copper pipe. 192.279 Section 192.279 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... Copper pipe. Copper pipe may not be threaded except that copper pipe used for joining screw fittings...

  7. 49 CFR 192.279 - Copper pipe.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Copper pipe. 192.279 Section 192.279 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... Copper pipe. Copper pipe may not be threaded except that copper pipe used for joining screw fittings...

  8. 49 CFR 192.279 - Copper pipe.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Copper pipe. 192.279 Section 192.279 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... Copper pipe. Copper pipe may not be threaded except that copper pipe used for joining screw fittings...

  9. 46 CFR 108.475 - Piping.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Extinguishing Systems Foam Extinguishing Systems § 108.475 Piping. (a) Each pipe, valve, and fitting in a foam... pipe, valve, and fitting must have support and protection from damage. (d) Each foam extinguishing... to remove liquid from the system. (e) Piping in a foam extinguishing system must be used only...

  10. 46 CFR 108.475 - Piping.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Extinguishing Systems Foam Extinguishing Systems § 108.475 Piping. (a) Each pipe, valve, and fitting in a foam... pipe, valve, and fitting must have support and protection from damage. (d) Each foam extinguishing... to remove liquid from the system. (e) Piping in a foam extinguishing system must be used only...

  11. 46 CFR 108.475 - Piping.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Extinguishing Systems Foam Extinguishing Systems § 108.475 Piping. (a) Each pipe, valve, and fitting in a foam... pipe, valve, and fitting must have support and protection from damage. (d) Each foam extinguishing... to remove liquid from the system. (e) Piping in a foam extinguishing system must be used only...

  12. 46 CFR 108.475 - Piping.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Extinguishing Systems Foam Extinguishing Systems § 108.475 Piping. (a) Each pipe, valve, and fitting in a foam... pipe, valve, and fitting must have support and protection from damage. (d) Each foam extinguishing... to remove liquid from the system. (e) Piping in a foam extinguishing system must be used only...

  13. Decontaminating Aluminum/Ammonia Heat Pipes

    NASA Technical Reports Server (NTRS)

    Jones, J. A.

    1985-01-01

    Internal gas slugs reduced or eliminated. Manufacturing method increases efficiency of aluminum heat pipes in which ammonia is working fluid by insuring pipe filled with nearly pure charge of ammonia. In new process heat pipe initially closed with stainless-steel valve instead of weld so pipe put through several cycles of filling, purging, and accelerated aging.

  14. 46 CFR 45.133 - Air pipes.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Air pipes. 45.133 Section 45.133 Shipping COAST GUARD....133 Air pipes. (a) Where an air pipe to any tank extends above the freeboard or superstructure deck— (1) The exposed part of the air pipe must be made of steel and of sufficient thickness to...

  15. 49 CFR 192.279 - Copper pipe.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Copper pipe. 192.279 Section 192.279 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... Copper pipe. Copper pipe may not be threaded except that copper pipe used for joining screw fittings...

  16. Heat pipe technology: A bibliography with abstracts

    NASA Technical Reports Server (NTRS)

    1971-01-01

    A cumulative bibliography on heat pipe research and development projects is presented. The subjects discussed are: (1) general information, (2) heat pipe applications, (3) heat pipe theory, (4) design and fabrication, (5) testing and operation, (6) subject and author index, and (7) heat pipe related patents.

  17. 49 CFR 195.114 - Used pipe.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Used pipe. 195.114 Section 195.114 Transportation... PIPELINE Design Requirements § 195.114 Used pipe. Any used pipe installed in a pipeline system must comply with § 195.112 (a) and (b) and the following: (a) The pipe must be of a known specification and...

  18. Variable conductance heat pipe technology

    NASA Technical Reports Server (NTRS)

    Marcus, B. D.; Edwards, D. K.; Anderson, W. T.

    1973-01-01

    Research and development programs in variable conductance heat pipe technology were conducted. The treatment has been comprehensive, involving theoretical and/or experimental studies in hydrostatics, hydrodynamics, heat transfer into and out of the pipe, fluid selection, and materials compatibility, in addition to the principal subject of variable conductance control techniques. Efforts were not limited to analytical work and laboratory experimentation, but extended to the development, fabrication and test of spacecraft hardware, culminating in the successful flight of the Ames Heat Pipe Experiment on the OAO-C spacecraft.

  19. Hydrological connectivity of soil pipes

    NASA Astrophysics Data System (ADS)

    Holden, J.

    2003-04-01

    Natural soil pipes are common in many parts of the world and particularly in blanket peat uplands yet there are problems in finding and defining soil pipe networks which are often located deep within the peat. Pipeflow can contribute a large proportion of runoff to the river systems in these upland environments and may significantly influence catchment sediment and solute yield. Ground penetrating radar (GPR) technology has recently been developed for non-destructive identification and mapping of soil pipes in peat catchments. While GPR can identify subsurface cavities, it cannot alone determine hydrological connectivity between one cavity and another. This poster presents results from an experiment to test the ability of GPR to establish hydrological connectivity between pipes through use of a tracer solution. Tracers such as sodium chloride were injected at a constant rate into an open pipe cavity. The GPR was moved across the test area downslope. The resultant radargrams were analysed and significantly increased reflectance was observed from a selection of cavities downslope. It was thus possible to determine hydrological connectivity of soil pipes within a dense pipe network across a hillslope without ground disturbance. In addition, tracers were added to the peat surface upslope of known pipe networks. It was possible to then trace the movement of water across and through the hillslope by using GPR to establish the connectivity of a range of flowpaths. Often pipe networks were supplied with water from overland flow entering through cracks and openings where the soil pipe was near the peat surface. Downslope, pipeflow contributed not only directly to streamflow but also to overland flow and near-surface throughflow on the hillslope. The same water that was within a pipe network at four metres depth could become near-surface throughflow outside of the pipe network a few metres down slope. These data allow the first three-dimensional picture of subsurface

  20. Abrasion protection in process piping

    SciTech Connect

    Accetta, J.

    1996-07-01

    Process piping often is subjected to failure from abrasion or a combination of abrasion and corrosion. Abrasion is a complex phenomenon, with many factors involved to varying degrees. Hard, mineral based alumina ceramic and basalt materials are used to provide protection against abrasion in many piping systems. Successful life extension examples are presented from many different industries. Lined piping components require special attention with regard to operating conditions as well as design and engineering considerations. Economic justification involves direct cost comparisons and avoided costs.

  1. Loop Heat Pipe Startup Behaviors

    NASA Technical Reports Server (NTRS)

    Ku, Jentung

    2016-01-01

    A loop heat pipe must start successfully before it can commence its service. The startup transient represents one of the most complex phenomena in the loop heat pipe operation. This paper discusses various aspects of loop heat pipe startup behaviors. Topics include the four startup scenarios, the initial fluid distribution between the evaporator and reservoir that determines the startup scenario, factors that affect the fluid distribution between the evaporator and reservoir, difficulties encountered during the low power startup, and methods to enhance the startup success. Also addressed are the pressure spike and pressure surge during the startup transient, and repeated cycles of loop startup and shutdown under certain conditions.

  2. APEX. AutoPIPE Extract Program

    SciTech Connect

    Cline, B.E.

    1992-07-01

    The AutoPIPE Extract Program (APEX) provides an interface between CADAM (Computer Aided Design and Manufacturing) Release 21 drafting software and the AutoPIPE, Version 4.4, piping analysis program. APEX produces the AutoPIPE batch input file that corresponds to the piping shown in a CADAM model. The card image file contains header cards, material cards, and pipe cross section cards as well as tee, bend, valve, and flange cards. Node numbers are automatically generated. APEX processes straight pipe, branch lines and ring geometries.

  3. Thermal laminarization of a stratified pipe flow

    SciTech Connect

    Oras, J.J.; Kasza, K.E.

    1984-01-01

    The present work constitutes a new program that grew out of a scoping assessment by ANL to determine the propensity for pipe stratification to occur in the reactor outlet nozzles and hot-leg piping of a generic LMFBR during events producing reverse pipe flow. This paper focuses on the role that thermal buoyancy plays relative to being able to laminarize a turbulent stratified shear zone in a horizontal pipe. The preceeding can influence the behavior of a pipe stratified-backflow-recirculation zone (cold plenum water down into the hot pipe flow) which developes as the result of a temperature difference between the pipe flow and the plenum.

  4. Heat pipe life and processing study

    NASA Technical Reports Server (NTRS)

    Antoniuk, D.; Luedke, E. E.

    1979-01-01

    The merit of adding water to the reflux charge in chemically and solvent cleaned aluminum/slab wick/ammonia heat pipes was evaluated. The effect of gas in the performance of three heat pipe thermal control systems was found significant in simple heat pipes, less significant in a modified simple heat pipe model with a short wickless pipe section. Use of gas data for the worst and best heat pipes of the matrix in a variable conductance heat pipe model showed a 3 C increase in the source temperature at full on condition after 20 and 246 years, respectively.

  5. Atomic scale study of corrugating and anticorrugating states on the bare Si(1 0 0) surface

    NASA Astrophysics Data System (ADS)

    Yengui, Mayssa; Pinto, Henry P.; Leszczynski, Jerzy; Riedel, Damien

    2015-02-01

    In this article, we study the origin of the corrugating and anticorrugating states through the electronic properties of the Si(1 0 0) surface via a low-temperature (9 K) scanning tunneling microscope (STM). Our study is based on the analysis of the STM topographies corrugation variations when related to the shift of the local density of states (LDOS) maximum in the [1 \\bar{{1}} 0] direction. Our experimental results are correlated with numerical simulations using the density-functional theory with hybrid Heyd-Scuseria-Ernzerhof (HSE06) functional to simulate the STM topographies, the projected density of states variations at different depths in the silicon surface as well as the three dimensional partial charge density distributions in real-space. This work reveals that the Si(1 0 0) surface exhibits two anticorrugating states at +0.8 and +2.8 V that are associated with a phase shift of the LDOS maximum in the unoccupied states STM topographies. By comparing the calculated data with our experimental results, we have been able to identify the link between the variations of the STM topographies corrugation and the shift of the LDOS maximum observed experimentally. Each surface voltage at which the STM topographies corrugation drops is defined as anticorrugating states. In addition, we have evidenced a sharp jump in the tunnel current when the second LDOS maximum shift is probed, whose origin is discussed and associated with the presence of Van Hove singularities.

  6. Radiative decay effects influence the local electromagnetic response of the monolayer graphene with surface corrugations in terahertz range

    NASA Astrophysics Data System (ADS)

    Firsov, Yu. A.; Firsova, N. E.

    2015-07-01

    We continue the study of surface corrugations influence on the monolayer graphene local electromagnetic response in terahertz range we started earlier. The effects of radiative decay, double-valley structure of charge carriers spectrum in graphene and the "breathing" corrugated surface form induced synthetic electric fields are taken into account. To fulfill this program the generalized nonlinear self-consistent-field equation is obtained. In case of weak external alternating electric field E→ext (t) =E→0 cos ωt for the obtained equation in linear approximation on the external electric field the exact solution is found. It shows that in this case we get local induced current paths depending on the surface form z = h (x , y) . This theoretical result qualitatively explains the corresponding experiments with local current patterns depending on the point by corrugations influence. The induced currents formula was obtained without using fully quantum approach which is necessary for theoretical description of such phenomenon in graphene nanoribbons. Besides the formulae obtained in the present paper could become the basis of the new method of the imaging of surface corrugations form for given experimental picture of local current paths.

  7. Intermediate Temperature Water Heat Pipe Tests

    NASA Technical Reports Server (NTRS)

    Devarakonda, Angirasa; Xiong, Da-Xi; Beach, Duane E.

    2005-01-01

    Heat pipes are among the most promising technologies for space radiator systems. Water heat pipes are explored in the intermediate temperature range of 400 to above 500 K. The thermodynamic and thermo-physical properties of water are reviewed in this temperature range. Test data are reported for a copper-water heat pipe. The heat pipe was tested under different orientations. Water heat pipes show promise in this temperature range. Fabrication and testing issues are being addressed.

  8. Intermediate Temperature Water Heat Pipe Tests

    NASA Technical Reports Server (NTRS)

    Devarakonda, Angirasa; Xiong, Daxi; Beach, Duane E.

    2004-01-01

    Heat pipes are among the most promising technologies for space radiator systems. Water heat pipes are explored in the intermediate temperature range of 400 to above 500 K. The thermodynamic and thermo-physical properties of water are reviewed in this temperature range. Test Data are reported for a copper-water heat pipe. The heat pipe was tested under different orientations. Water heat pipes show promise in this temperature range.Fabrication and testing issues are being addressed.

  9. Light pipes for LED measurements

    NASA Technical Reports Server (NTRS)

    Floyd, S. R.; Thomas, E. F., Jr.

    1976-01-01

    Light pipe directly couples LED optical output to single detector. Small area detector measures total optical output of diode. Technique eliminates thermal measurement problems and channels optical output to remote detector.

  10. Method for casting polyethylene pipe

    NASA Technical Reports Server (NTRS)

    Elam, R. M., Jr.

    1973-01-01

    Short lengths of 7-cm ID polyethylene pipe are cast in a mold which has a core made of room-temperature-vulcanizable (RTV) silicone. Core expands during casting and shrinks on cooling to allow for contraction of the polyethylene.

  11. Loop Heat Pipe Startup Behaviors

    NASA Technical Reports Server (NTRS)

    Ku, Jentung

    2014-01-01

    A loop heat pipe must start successfully before it can commence its service. The start-up transient represents one of the most complex phenomena in the loop heat pipe operation. This paper discusses various aspects of loop heat pipe start-up behaviors. Topics include the four start-up scenarios, the initial fluid distribution between the evaporator and reservoir that determines the start-up scenario, factors that affect the fluid distribution between the evaporator and reservoir, difficulties encountered during the low power start-up, and methods to enhance the start-up success. Also addressed are the thermodynamic constraint between the evaporator and reservoir in the loop heat pipe operation, the superheat requirement for nucleate boiling, pressure spike and pressure surge during the start-up transient, and repeated cycles of loop start-up andshutdown under certain conditions.

  12. Physics of heat pipe rewetting

    NASA Technical Reports Server (NTRS)

    Chan, S. H.

    1994-01-01

    This is the final report which summarizes the research accomplishments under the project entitled 'Physics of Heat Pipe Rewetting' under NASA Grant No. NAG 9-525, Basic, during the period of April 1, 1991 to January 31, 1994. The objective of the research project was to investigate both analytically and experimentally the rewetting characteristics of the heated, grooved plate. The grooved plate is to simulate the inner surface of the vapor channel in monogroove heat pipes for space station design. In such designs, the inner surface of the vapor channel is threaded with monogrooves. When the heat pipe is thermally overloaded, dryout of the monogroove surface occurs. Such a dryout surface should be promptly rewetted to prevent the failure of the heat pipe operation in the thermal radiator of the space station.

  13. Effects of carbon coating and pore corrugation on capillary condensation of nitrogen in SBA-15 mesoporous silica.

    PubMed

    Morishige, Kunimitsu

    2013-09-24

    To examine the origin of an ink-bottle-like structure in SBA-15 formed by carbon coating and the effects of pore corrugation on capillary condensation and evaporation of a vapor in the cylindrical pores, we measured the adsorption isotherms of nitrogen at 77 K on 10 kinds of SBA-15 samples before and after a carbon coating process by the exposure to acetylene at 1073 K, as well as desorption scanning curves and subloops on the untreated samples. These SBA-15 samples were synthesized under the different conditions of initial SiO2/P123 ratio and hydrothermal treatment. SBA-15 with relatively large microporosity tends to form easily constrictions inside the main channels by the carbon coating. This strongly suggests that the rough pore walls of SBA-15 may induce the incomplete wetting of carbon layers on the pore walls to form the constrictions inside the cylindrical pores. A comparison of two subloops implies that the pores of SBA-15 synthesized with a SiO2/P123 ratio of 75 consist of an assembly of connecting domains of different diameters; that is, the pores are highly corrugated. For SBA-15 synthesized with a SiO2/P123 ratio of 60, the amplitude of the pore corrugation is significantly decreased by the prolonged hydrothermal treatment at 373 K. On the other hand, for SBA-15 synthesized with a SiO2/P123 ratio of 45, the amplitude of the corrugation is negligibly small, although the cylindrical pores are interconnected through narrow necks with each other. It is found that the smaller the amplitude of the pore corrugation, the smaller the width of the hysteresis loop. PMID:23977846

  14. Mapping Temperatures On Heat Pipes

    NASA Technical Reports Server (NTRS)

    Gunnerson, Fred S.; Thorncroft, Glen E.

    1993-01-01

    Paints containing thermochromic liquid crystals (TLC's) used to map temperatures on heat pipes and thermosyphons. Color of thermally sensitive TLC coat changes reversibly upon heating or cooling. Each distinct color indicates particular temperature. Transient and steady-state isotherms become visible as colored bands. Positions and movements of bands yield information about startup transients, steady-state operation, cooler regions containing noncondensible gas, and other phenomena relevant to performance of heat pipe.

  15. Heat pipe turbine vane cooling

    SciTech Connect

    Langston, L.; Faghri, A.

    1995-12-31

    The applicability of using heat pipe principles to cool gas turbine vanes is addressed in this beginning program. This innovative concept involves fitting out the vane interior as a heat pipe and extending the vane into an adjacent heat sink, thus transferring the vane incident heat transfer through the heat pipe to heat sink. This design provides an extremely high heat transfer rate and a uniform temperature along the vane due to the internal change of phase of the heat pipe working fluid. Furthermore, this technology can also eliminate hot spots at the vane leading and trailing edges and increase the vane life by preventing thermal fatigue cracking. There is also the possibility of requiring no bleed air from the compressor, and therefore eliminating engine performance losses resulting from the diversion of compressor discharge air. Significant improvement in gas turbine performance can be achieved by using heat pipe technology in place of conventional air cooled vanes. A detailed numerical analysis of a heat pipe vane will be made and an experimental model will be designed in the first year of this new program.

  16. Heat pipe cooled power magnetics

    NASA Technical Reports Server (NTRS)

    Chester, M. S.

    1979-01-01

    A high frequency, high power, low specific weight (0.57 kg/kW) transformer developed for space use was redesigned with heat pipe cooling allowing both a reduction in weight and a lower internal temperature rise. The specific weight of the heat pipe cooled transformer was reduced to 0.4 kg/kW and the highest winding temperature rise was reduced from 40 C to 20 C in spite of 10 watts additional loss. The design loss/weight tradeoff was 18 W/kg. Additionally, allowing the same 40 C winding temperature rise as in the original design, the KVA rating is increased to 4.2 KVA, demonstrating a specific weight of 0.28 kg/kW with the internal loss increased by 50W. This space environment tested heat pipe cooled design performed as well electrically as the original conventional design, thus demonstrating the advantages of heat pipes integrated into a high power, high voltage magnetic. Another heat pipe cooled magnetic, a 3.7 kW, 20A input filter inductor was designed, developed, built, tested, and described. The heat pipe cooled magnetics are designed to be Earth operated in any orientation.

  17. Pipe weld crown removal device

    DOEpatents

    Sword, Charles K.; Sette, Primo J.

    1992-01-01

    A device is provided for grinding down the crown of a pipe weld joining aligned pipe sections so that the weld is substantially flush with the pipe sections joined by the weld. The device includes a cage assembly comprising a pair of spaced cage rings adapted to be mounted for rotation on the respective pipe sections on opposite sides of the weld, a plurality of grinding wheels, supported by the cage assembly for grinding down the crown of the weld, and a plurality of support shafts, each extending longitudinally along the joined pipe sections, parallel thereto, for individually mounting respective grinding wheels. Each end of the support shafts is mounted for rotation in a bearing assembly housed within a radially directed opening in a corresponding one of the cage rings so as to provide radial movement of the associated shaft, and thus of the associated grinding wheel, towards and away from the weld. A first drive sprocket provides rotation of the cage assembly around the pipe sections while a second drive unit, driven by a common motor, provides rotation of the grinding wheels.

  18. Heat pipe turbine vane cooling

    SciTech Connect

    Langston, L.; Faghri, A.

    1995-10-01

    The applicability of using heat pipe principles to cool gas turbine vanes is addressed in this beginning program. This innovative concept involves fitting out the vane interior as a heat pipe and extending the vane into an adjacent heat sink, thus transferring the vane incident heat transfer through the heat pipe to heat sink. This design provides an extremely high heat transfer rate and an uniform temperature along the vane due to the internal change of phase of the heat pipe working fluid. Furthermore, this technology can also eliminate hot spots at the vane leading and trailing edges and increase the vane life by preventing thermal fatigue cracking. There is also the possibility of requiring no bleed air from the compressor, and therefore eliminating engine performance losses resulting from the diversion of compressor discharge air. Significant improvement in gas turbine performance can be achieved by using heat pipe technology in place of conventional air cooled vanes. A detailed numerical analysis of a heat pipe vane will be made and an experimental model will be designed in the first year of this new program.

  19. Automated internal pipe cutting device

    DOEpatents

    Godlewski, William J.; Haffke, Gary S.; Purvis, Dale; Bashar, Ronald W.; Jones, Stewart D.; Moretti, Jr., Henry; Pimentel, James

    2003-01-21

    The invention is a remotely controlled internal pipe cutting device primarily used for cutting pipes where the outside of the pipe is inaccessible at the line where the cut is to be made. The device includes an axial ram within a rotational cylinder which is enclosed in a housing. The housing is adapted for attachment to an open end of the pipe and for supporting the ram and cylinder in cantilever fashion within the pipe. A radially movable cutter, preferably a plasma arc torch, is attached to the distal end of the ram. A drive mechanism, containing motors and mechanical hardware for operating the ram and cylinder, is attached to the proximal end of the housing. The ram and cylinder provide for moving the cutter axially and circumferentially, and a cable assembly attached to a remote motor provide for the movement of the cutter radially, within the pipe. The control system can be adjusted and operated remotely to control the position and movement of the cutter to obtain the desired cut. The control system can also provide automatic standoff control for a plasma arc torch.

  20. High second-order nonlinear response of platinum nanoflowers: the role of surface corrugation.

    PubMed

    Ngo, Hoang Minh; Lai, Ngoc Diep; Ledoux-Rak, Isabelle

    2016-02-14

    Platinum nanoflowers (PtNFs) were elaborated using the seed-mediated growth technique applied to monodisperse platinum nanoparticles (∼3.0 nm) synthesized by the chemical reduction method. The X-ray diffraction pattern confirmed the formation of face-centered-cubic platinum nanocrystals. We report the Harmonic Light Scattering (HLS) properties of PtNFs for six different diameters (∼7.0; 8.0; 10.0; 14.0; 20.0 and 31.0 nm). From these HLS data we infer, for the first time, large hyperpolarizability β values of PtNFs. These very high β values of PtNFs are assigned mainly to highly corrugated surfaces for nanoparticles with irregular shapes.

  1. Comparison of finite source and plane wave scattering from corrugated surfaces

    NASA Technical Reports Server (NTRS)

    Levine, D. M.

    1977-01-01

    The choice of a plane wave to represent incident radiation in the analysis of scatter from corrugated surfaces was examined. The physical optics solution obtained for the scattered fields due to an incident plane wave was compared with the solution obtained when the incident radiation is produced by a source of finite size and finite distance from the surface. The two solutions are equivalent if the observer is in the far field of the scatterer and the distance from observer to scatterer is large compared to the radius of curvature at the scatter points, condition not easily satisfied with extended scatterers such as rough surfaces. In general, the two solutions have essential differences such as in the location of the scatter points and the dependence of the scattered fields on the surface properties. The implication of these differences to the definition of a meaningful radar cross section was examined.

  2. Energy shift of collective electron excitations in highly corrugated graphitic nanostructures: Experimental and theoretical investigation

    SciTech Connect

    Sedelnikova, O. V. Bulusheva, L. G.; Okotrub, A. V.; Asanov, I. P.; Yushina, I. V.

    2014-04-21

    Effect of corrugation of hexagonal carbon network on the collective electron excitations has been studied using optical absorption and X-ray photoelectron spectroscopy in conjunction with density functional theory calculations. Onion-like carbon (OLC) was taken as a material, where graphitic mantle enveloping agglomerates of multi-shell fullerenes is strongly curved. Experiments showed that positions of π and π + σ plasmon modes as well as π → π* absorption peak are substantially redshifted for OLC as compared with those of highly ordered pyrolytic graphite and thermally exfoliated graphite consisted of planar sheets. This effect was reproduced in behavior of dielectric functions of rippled graphite models calculated within the random phase approximation. We conclude that the energy of electron excitations in graphitic materials could be precisely tuned by a simple bending of hexagonal network without change of topology. Moreover, our investigation suggests that in such materials optical exciton can transfer energy to plasmon non-radiatively.

  3. Euler buckling, membrane corrugation and pore formation induced by antimicrobial peptide

    NASA Astrophysics Data System (ADS)

    Golubovic, Leonardo; Gao, Lianghui; Chen, Licui; Jia, Nana; Fang, Weihai

    2014-03-01

    Antimicrobial peptides serve as defense weapons against bacteria. They are secreted by organisms of plants and animals and have a wide variety in composition and structure. In this study, we theoretically explore the effects of the antimicrobial peptides on the lipid bilayer membrane by using analytic arguments and the coarse grained dissipative particle dynamics simulations. We study peptide/lipid membrane complexes by considering peptides with various structure, hydrophobicity and peptide/lipid interaction strength. The role of lipid/water interaction is also discussed. We discuss a rich variety of membrane morphological changes induced by peptides, such as pore formation, membrane corrugation and Euler buckling. Such buckled membrane states have been indeed seen in a number of experiments with bacteria affected by peptide, yet this is the first theoretical study addressing these phenomena more deeply.

  4. Theory of the corrugation instability of a piston-driven shock wave.

    PubMed

    Bates, J W

    2015-01-01

    We analyze the two-dimensional stability of a shock wave driven by a steadily moving corrugated piston in an inviscid fluid with an arbitrary equation of state. For h≤-1 or h>h(c), where h is the D'yakov parameter and h(c) is the Kontorovich limit, we find that small perturbations on the shock front are unstable and grow--at first quadratically and later linearly--with time. Such instabilities are associated with nonequilibrium fluid states and imply a nonunique solution to the hydrodynamic equations. The above criteria are consistent with instability limits observed in shock-tube experiments involving ionizing and dissociating gases and may have important implications for driven shocks in laser-fusion, astrophysical, and/or detonation studies.

  5. Focusing Radially Polarized Light by a Concentrically Corrugated Silver Film without a Hole

    NASA Astrophysics Data System (ADS)

    Wróbel, Piotr; Pniewski, Jacek; Antosiewicz, Tomasz J.; Szoplik, Tomasz

    2009-05-01

    We report a phenomenon of focusing a radially polarized beam from the visible range by a silver film with no hole on the optical axis and double-sided concentric corrugations. The axes of symmetry of grooves and the illuminating beam coincide. An Ag lens of 100 nm thickness, five grooves, of which the outermost has 5μm diameter, at λ=400nm transmits 22% of electric energy and focuses light into a 0.2λ2 spot area at a focal length close to 2λ, while at λ=500nm the results are 11%, 0.16λ2 and λ, respectively. This Ag lens focuses without contribution of evanescent waves a far-field source into a far-field spot. The nanolens acts like a refractive optical system of high numerical aperture close to unity.

  6. The evolution of the magnetic moment in a corrugated magnetic field.

    PubMed

    Demokan, O.; Mirnov, V. V.

    1997-09-01

    In the first part, the equations of motion in a weakly corrugated, periodic magnetic field are linearized and solved by using paraxial approximation, to describe the model and the associated resonance condition. In the second part, the nonlinear evolution of the magnetic moment of resonant particles, in connection with their axial displacement is investigated analytically by using the multiple scale method. It is seen that the linear evolution is converted into a slow and periodic oscillation around the unperturbed value, with a considerable amplitude. The analytic expressions for the period and amplitude of the oscillations are derived and compared with the numerical simulations, which are also presented. Finally, the limitations of the paraxial approximation are concluded by investigating the numerical simulations, with actual field expressions. (c) 1997 American Institute of Physics.

  7. Radial Corrugations of Multi-Walled Carbon Nanotubes Driven by Inter-Wall Nonbonding Interactions

    PubMed Central

    2011-01-01

    We perform large-scale quasi-continuum simulations to determine the stable cross-sectional configurations of free-standing multi-walled carbon nanotubes (MWCNTs). We show that at an inter-wall spacing larger than the equilibrium distance set by the inter-wall van der Waals (vdW) interactions, the initial circular cross-sections of the MWCNTs are transformed into symmetric polygonal shapes or asymmetric water-drop-like shapes. Our simulations also show that removing several innermost walls causes even more drastic cross-sectional polygonization of the MWCNTs. The predicted cross-sectional configurations agree with prior experimental observations. We attribute the radial corrugations to the compressive stresses induced by the excessive inter-wall vdW energy release of the MWCNTs. The stable cross-sectional configurations provide fundamental guidance to the design of single MWCNT-based devices and shed lights on the mechanical control of electrical properties. PMID:27502675

  8. Mastered dispersion of material resonators: Broad corrugated waveguides working under the Littrow regime

    NASA Astrophysics Data System (ADS)

    Benisty, H.; Piskunov, N.

    2013-04-01

    An anomalous dispersion for modes of a material resonator is highly desired to form frequency combs. A resonator free-spectral-range (FSR) controlled by shape so as to increase with frequency ω/2π compensates the normal index dispersion ∂n/∂ω > 0, producing evenly spaced resonances. Only special shapes achieve this scope. We show here that broad periodic corrugated waveguides working at Littrow regime feature such an increasing trend ∂FSR/∂ω > 0. We outline experimentally this trend on silicon-on-insulator devices designed for 45° Littrow operation. We predict dispersion-free silicon-based designs across the 1.4-4.0 μm mid-infrared range.

  9. Dynamical back-action at 5.5 GHz in a corrugated optomechanical beam

    SciTech Connect

    Navarro-Urrios, D.; Gomis-Bresco, J.; Alzina, F.; El-Jallal, S.; Oudich, M.; Pennec, Y.; Djafari-Rouhani, B.; Pitanti, A.; Capuj, N.; Tredicucci, A.; Griol, A.; Martínez, A.; Sotomayor Torres, C. M.

    2014-12-15

    We report on the optomechanical properties of a breathing mechanical mode oscillating at 5.5 GHz in a 1D corrugated Si nanobeam. This mode has an experimental single-particle optomechanical coupling rate of |g{sub o,OM}| = 1.8 MHz (|g{sub o,OM}|/2π = 0.3 MHz) and shows strong dynamical back-action effects at room temperature. The geometrical flexibility of the unit-cell would lend itself to further engineering of the cavity region to localize the mode within the full phononic band-gap present at 4 GHz while keeping high g{sub o,OM} values. This would lead to longer lifetimes at cryogenic temperatures, due to the suppression of acoustic leakage.

  10. High second-order nonlinear response of platinum nanoflowers: the role of surface corrugation

    NASA Astrophysics Data System (ADS)

    Ngo, Hoang Minh; Lai, Ngoc Diep; Ledoux-Rak, Isabelle

    2016-02-01

    Platinum nanoflowers (PtNFs) were elaborated using the seed-mediated growth technique applied to monodisperse platinum nanoparticles (~3.0 nm) synthesized by the chemical reduction method. The X-ray diffraction pattern confirmed the formation of face-centered-cubic platinum nanocrystals. We report the Harmonic Light Scattering (HLS) properties of PtNFs for six different diameters (~7.0 8.0; 10.0; 14.0; 20.0 and 31.0 nm). From these HLS data we infer, for the first time, large hyperpolarizability β values of PtNFs. These very high β values of PtNFs are assigned mainly to highly corrugated surfaces for nanoparticles with irregular shapes.Platinum nanoflowers (PtNFs) were elaborated using the seed-mediated growth technique applied to monodisperse platinum nanoparticles (~3.0 nm) synthesized by the chemical reduction method. The X-ray diffraction pattern confirmed the formation of face-centered-cubic platinum nanocrystals. We report the Harmonic Light Scattering (HLS) properties of PtNFs for six different diameters (~7.0 8.0; 10.0; 14.0; 20.0 and 31.0 nm). From these HLS data we infer, for the first time, large hyperpolarizability β values of PtNFs. These very high β values of PtNFs are assigned mainly to highly corrugated surfaces for nanoparticles with irregular shapes. Electronic supplementary information (ESI) available: The recalculated β and β' values inferred from data by Galletto et al.15 in AuNSs using their reported β values per nanoparticle corrected. See DOI: 10.1039/c5nr07571h

  11. Organ pipe resonance induced vibration in piping system

    SciTech Connect

    Wang, T.

    1996-12-01

    Acoustic-induced vibration is a fluid-structure interaction phenomenon. The feedback mechanism between the acoustic pressure pulsation and the structure movements determines the excited acoustic modes which, in turn, amplify the structure response when confidence frequency and mode shape matching occurs. The acoustic modes are not determined from the acoustic boundary conditions alone, structure feedback is as responsible for determining the acoustic modes and shaping the resulting forcing functions. Acoustic-induced piping vibration, when excited, does not attenuate much with distance. Pressure pulsation can be transmitted throughout the piping system and its branch connections. It is this property that makes vibration monitoring difficult, because vibration can surface at locations far away from the acoustic source when resonance occurs. For a large piping system with interconnected branches, the monitoring task can be formidable, particularly when there is no indication what the real source is. In organ pipe resonance induced vibration, the initiating acoustic source may be inconspicuous or unavoidable during operation. In these situations, the forcing function approach can offer an optimal tool for vibration assessment. The forcing function approach was used in the evaluation of a standby steam piping vibration problem. Monitoring locations and instrument specifications were determined from the acoustic eigenfunction profiles. Measured data confirmed the presence of coherent vibrations in the large bore piping. The developed forcing function permits design evaluation of the piping system, which leads to remedial actions and enables fatigue life determination, thus providing confidence to system operation. The forcing function approach is shown to be useful in finding potential vibration area and verifying the integrity of weak structure links. Application is to steam lines at BWR plants.

  12. Leaks in pipe networks

    USGS Publications Warehouse

    Pudar, Ranko S.; Liggett, James A.

    1992-01-01

    Leak detection in water-distribution systems can be accomplished by solving an inverse problem using measurements of pressure and/or flow. The problem is formulated with equivalent orifice areas of possible leaks as the unknowns. Minimization of the difference between measured and calculated heads produces a solution for the areas. The quality of the result depends on number and location of the measurements. A sensitivity matrix is key to deciding where to make measurements. Both location and magnitude of leaks are sensitive to the quantity and quality of pressure measurements and to how well the pipe friction parameters are known. The overdetermined problem (more measurements than suspected leaks) gives the best results, but some information can be derived from the underdetermined problem. The variance of leak areas, based on the quality of system characteristics and pressure data, indicates the likely accuracy of the results. The method will not substitute for more traditional leak surveys but can serve as a guide and supplement.

  13. Piping inspection round robin

    SciTech Connect

    Heasler, P.G.; Doctor, S.R.

    1996-04-01

    The piping inspection round robin was conducted in 1981 at the Pacific Northwest National Laboratory (PNNL) to quantify the capability of ultrasonics for inservice inspection and to address some aspects of reliability for this type of nondestructive evaluation (NDE). The round robin measured the crack detection capabilities of seven field inspection teams who employed procedures that met or exceeded the 1977 edition through the 1978 addenda of the American Society of Mechanical Engineers (ASME) Section 11 Code requirements. Three different types of materials were employed in the study (cast stainless steel, clad ferritic, and wrought stainless steel), and two different types of flaws were implanted into the specimens (intergranular stress corrosion cracks (IGSCCs) and thermal fatigue cracks (TFCs)). When considering near-side inspection, far-side inspection, and false call rate, the overall performance was found to be best in clad ferritic, less effective in wrought stainless steel and the worst in cast stainless steel. Depth sizing performance showed little correlation with the true crack depths.

  14. Magnetic refrigeration apparatus with heat pipes

    DOEpatents

    Barclay, J.A.; Prenger, F.C. Jr.

    1985-10-25

    A magnetic refrigerator operating in the 4 to 20 K range utilizes heat pipes to transfer heat to and from the magnetic material at the appropriate points during the material's movement. In one embodiment circular disks of magnetic material can be interleaved with the ends of the heat pipes. In another embodiment a mass of magnetic material reciprocatingly moves between the end of the heat pipe or pipes that transmits heat from the object of cooling to the magnetic material and the end of the heat pipe or pipes that transmits heat from the magnetic material to a heat sink.

  15. Magnetic refrigeration apparatus with heat pipes

    DOEpatents

    Barclay, John A.; Prenger, Jr., F. Coyne

    1987-01-01

    A magnetic refrigerator operating in the 4 to 20 K range utilizes heat pipes to transfer heat to and from the magnetic material at the appropriate points during the material's movement. In one embodiment circular disks of magnetic material can be interleaved with the ends of the heat pipes. In another embodiment a mass of magnetic material reciprocatingly moves between the end of the heat pipe of pipes that transmits heat from the object of cooling to the magnetic material and the end of the heat pipe or pipes that transmits heat from the magnetic material to a heat sink.

  16. Flexible ultrasonic pipe inspection apparatus

    SciTech Connect

    Jenkins, C.F.; Howard, B.D.

    1998-06-23

    A flexible, modular ultrasonic pipe inspection apparatus, comprises a flexible, hollow shaft that carries a plurality of modules, including at least one rotatable ultrasonic transducer, a motor/gear unit, and a position/signal encoder. The modules are connected by flexible knuckle joints that allow each module of the apparatus to change its relative orientation with respect to a neighboring module, while the shaft protects electrical wiring from kinking or buckling while the apparatus moves around a tight corner. The apparatus is moved through a pipe by any suitable means, including a tether or drawstring attached to the nose or tail, differential hydraulic pressure, or a pipe pig. The rotational speed of the ultrasonic transducer and the forward velocity of the apparatus are coordinated so that the beam sweeps out the entire interior surface of the pipe, enabling the operator to accurately assess the condition of the pipe wall and determine whether or not leak-prone corrosion damage is present. 7 figs.

  17. Pipe crawler with extendable legs

    DOEpatents

    Zollinger, W.T.

    1992-06-16

    A pipe crawler for moving through a pipe in inchworm fashion having front and rear leg assemblies separated by air cylinders to increase and decrease the spacing between assemblies. Each leg of the four legs of an assembly is moved between a wall-engaging, extended position and a retracted position by a separate air cylinder. The air cylinders of the leg assemblies are preferably arranged in pairs of oppositely directed cylinders with no pair lying in the same axial plane as another pair. Therefore, the cylinders can be as long as a leg assembly is wide and the crawler can crawl through sections of pipes where the diameter is twice that of other sections. The crawler carries a valving system, a manifold to distribute air supplied by a single umbilical air hose to the various air cylinders in a sequence controlled electrically by a controller. The crawler also utilizes a rolling mechanism, casters in this case, to reduce friction between the crawler and pipe wall thereby further extending the range of the pipe crawler. 8 figs.

  18. Pipe crawler with extendable legs

    DOEpatents

    Zollinger, William T.

    1992-01-01

    A pipe crawler for moving through a pipe in inchworm fashion having front and rear leg assemblies separated by air cylinders to increase and decrease the spacing between assemblies. Each leg of the four legs of an assembly is moved between a wall-engaging, extended position and a retracted position by a separate air cylinder. The air cylinders of the leg assemblies are preferably arranged in pairs of oppositely directed cylinders with no pair lying in the same axial plane as another pair. Therefore, the cylinders can be as long a leg assembly is wide and the crawler can crawl through sections of pipes where the diameter is twice that of other sections. The crawler carries a valving system, a manifold to distribute air supplied by a single umbilical air hose to the various air cylinders in a sequence controlled electrically by a controller. The crawler also utilizes a rolling mechanism, casters in this case, to reduce friction between the crawler and pipe wall thereby further extending the range of the pipe crawler.

  19. Centrally activated pipe snubbing system

    DOEpatents

    Cawley, William E.

    1985-01-01

    An electromechanical pipe snubbing system and an electromechanical pipe snubber. In the system, each pipe snubber, in a set of pipe snubbers, has an electromechanical mechanism to lock and unlock the snubber. A sensor, such as a seismometer, measures a quantity related to making a snubber locking or unlocking decision. A control device makes an electrical connection between a power supply and each snubber's electromechanical mechanism to simultaneously lock each snubber when the sensor measurement indicates a snubber locking condition. The control device breaks the connection to simultaneously unlock each snubber when the sensor measurement indicates a snubber unlocking condition. In the snubber, one end of the shaft slides within a bore in one end of a housing. The other end of the shaft is rotatably attached to a pipe; the other end of the housing is rotatively attached to a wall. The snubber's electromechanical mechanism locks the slidable end of the shaft to the housing and unlocks that end from the housing. The electromechanical mechanism permits remote testing and lockup status indication for each snubber.

  20. Repair of filament wound composite pipes

    NASA Astrophysics Data System (ADS)

    Amali, Ramin; Arnall, Heather

    2015-07-01

    Filament wound pipes are used in a wide variety of industries, due to the advantages composites have over metal pipes, such as a high strength to weight ratio, and resistance against frost, corrosion and heat. Composite pipes require minimal maintenance to ensure they are safe. Any damage occurring in composite pipes could lead to failure; therefore all damage should be assessed through NDT. If it is decided that the damage makes the pipe unsafe then a decision needs to be made whether to repair or replace the pipe. Repairing a composite pipe can be quicker, easier and cheaper than replacing it and can restore the strength of the pipe effectively. This investigation looks at the repair process and the parameters involved in determining the strength of the pipe following repair through the use of over 150 models in FEA software, Abaqus. Parameters considered include the pipe diameter and thickness, damage removal size and wrap width and thickness. It was found that if the pipe is thin-walled then it can be assumed that the pipe's thickness has no effect on the FOS following repair. Formulas were created to predict the FOS following repair for varying pipe diameters, damage sizes and wrap thickness. Formulas were also created to determine the wrap width required for varying wrap thicknesses and damage sizes.

  1. Heat pipe design handbook, part 1

    NASA Technical Reports Server (NTRS)

    Skrabek, E. A.

    1972-01-01

    The development and characteristics of heat pipes are examined. The subjects discussed are: (1) principles of operation, (2) heat pipe theory, (3) pressure gradient effects, (4) variable conductance, (5) design procedure, and (6) performance limit evaluation.

  2. Flat heat pipe design, construction, and analysis

    SciTech Connect

    Voegler, G.; Boughey, B.; Cerza, M.; Lindler, K.W.

    1999-08-02

    This paper details the design, construction and partial analysis of a low temperature flat heat pipe in order to determine the feasibility of implementing flat heat pipes into thermophotovoltaic (TPV) energy conversion systems.

  3. Emission Characteristics of Organic Light-Emitting Diodes and Organic Thin-Films with Planar and Corrugated Structures

    PubMed Central

    Wei, Mao-Kuo; Lin, Chii-Wann; Yang, Chih-Chung; Kiang, Yean-Woei; Lee, Jiun-Haw; Lin, Hoang-Yan

    2010-01-01

    In this paper, we review the emission characteristics from organic light-emitting diodes (OLEDs) and organic molecular thin films with planar and corrugated structures. In a planar thin film structure, light emission from OLEDs was strongly influenced by the interference effect. With suitable design of microcavity structure and layer thicknesses adjustment, optical characteristics can be engineered to achieve high optical intensity, suitable emission wavelength, and broad viewing angles. To increase the extraction efficiency from OLEDs and organic thin-films, corrugated structure with micro- and nano-scale were applied. Microstructures can effectively redirects the waveguiding light in the substrate outside the device. For nanostructures, it is also possible to couple out the organic and plasmonic modes, not only the substrate mode. PMID:20480033

  4. Introduction to Loop Heat Pipes

    NASA Technical Reports Server (NTRS)

    Ku, Jentung

    2015-01-01

    This is the presentation file for the short course Introduction to Loop Heat Pipes, to be conducted at the 2015 Thermal Fluids and Analysis Workshop, August 3-7, 2015, Silver Spring, Maryland. This course will discuss operating principles and performance characteristics of a loop heat pipe. Topics include: 1) pressure profiles in the loop; 2) loop operating temperature; 3) operating temperature control; 4) loop startup; 4) loop shutdown; 5) loop transient behaviors; 6) sizing of loop components and determination of fluid inventory; 7) analytical modeling; 8) examples of flight applications; and 9) recent LHP developments.

  5. Cryogenic thermal diode heat pipes

    NASA Technical Reports Server (NTRS)

    Alario, J.

    1979-01-01

    The development of spiral artery cryogenic thermal diode heat pipes was continued. Ethane was the working fluid and stainless steel the heat pipe material in all cases. The major tasks included: (1) building a liquid blockage (blocking orifice) thermal diode suitable for the HEPP space flight experiment; (2) building a liquid trap thermal diode engineering model; (3) retesting the original liquid blockage engineering model, and (4) investigating the startup dynamics of artery cryogenic thermal diodes. An experimental investigation was also conducted into the wetting characteristics of ethane/stainless steel systems using a specially constructed chamber that permitted in situ observations.

  6. FRP and pipe flexibility analysis

    SciTech Connect

    Eisenman, J.D.

    1999-11-01

    Fiberglass Reinforced Plastic (FRP) is an excellent material of construction for piping carrying corrosive media. Since FRP is an anisotropic material additional design detail is required to assure safe and reliable service. For this reason the resin selection, material specification, construction and detailed engineering are critical to the success of the project. This paper moves through this engineering process, including resin systems, fitting construction and pipe flexibility analysis. A comparison of fitting construction methods and discussion of stress/flexibility analysis design approaches will also be provided.

  7. Heat pipe thermal conditioning panel

    NASA Technical Reports Server (NTRS)

    Saaski, E. W.; Loose, J. D.; Mccoy, K. E.

    1974-01-01

    Thermal control of electronic hardware and experiments on future space vehicles is critical to proper functioning and long life. Thermal conditioning panels (cold plates) are a baseline control technique in current conceptual studies. Heat generating components mounted on the panels are typically cooled by fluid flowing through integral channels within the panel. However, replacing the pumped fluid coolant loop within the panel with heat pipes offers attractive advantages in weight, reliability, and installation. This report describes the development and fabrication of two large 0.76 x 0.76 m heat pipe thermal conditioning panels to verify performance and establish the design concept.

  8. Heat pipe modeling and simulation

    SciTech Connect

    Peterson, G.P.

    1985-01-01

    Presented herein is a parametric study of the defining equations which govern the steady state operational characteristics of the Grumman Monogroove Dual Passage Heat Pipe. These defining equations are combined to develop a mathematical model which describes and predicts the operational and performance capabilities of a specific heat pipe, given the necessary physical characteristics and working fluid. Included is a brief review of the current literature, a discussion of the governing equations, and a description of both the mathematical and computer model. Final results of preliminary test runs of the model are presented and compared with experimental tests performed by Grumman on actual prototypes.

  9. 46 CFR 61.15-5 - Steam piping.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... removed and the piping thoroughly examined. (b) All steam piping subject to pressure from the main boiler... 46 Shipping 2 2014-10-01 2014-10-01 false Steam piping. 61.15-5 Section 61.15-5 Shipping COAST... Periodic Tests of Piping Systems § 61.15-5 Steam piping. (a) Main steam piping shall be subjected to...

  10. 46 CFR 61.15-5 - Steam piping.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... removed and the piping thoroughly examined. (b) All steam piping subject to pressure from the main boiler... 46 Shipping 2 2013-10-01 2013-10-01 false Steam piping. 61.15-5 Section 61.15-5 Shipping COAST... Periodic Tests of Piping Systems § 61.15-5 Steam piping. (a) Main steam piping shall be subjected to...

  11. 46 CFR 61.15-5 - Steam piping.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... removed and the piping thoroughly examined. (b) All steam piping subject to pressure from the main boiler... 46 Shipping 2 2012-10-01 2012-10-01 false Steam piping. 61.15-5 Section 61.15-5 Shipping COAST... Periodic Tests of Piping Systems § 61.15-5 Steam piping. (a) Main steam piping shall be subjected to...

  12. 46 CFR 61.15-5 - Steam piping.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... removed and the piping thoroughly examined. (b) All steam piping subject to pressure from the main boiler... 46 Shipping 2 2010-10-01 2010-10-01 false Steam piping. 61.15-5 Section 61.15-5 Shipping COAST... Periodic Tests of Piping Systems § 61.15-5 Steam piping. (a) Main steam piping shall be subjected to...

  13. 46 CFR 61.15-5 - Steam piping.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... removed and the piping thoroughly examined. (b) All steam piping subject to pressure from the main boiler... 46 Shipping 2 2011-10-01 2011-10-01 false Steam piping. 61.15-5 Section 61.15-5 Shipping COAST... Periodic Tests of Piping Systems § 61.15-5 Steam piping. (a) Main steam piping shall be subjected to...

  14. High-Capacity Heat-Pipe Evaporator

    NASA Technical Reports Server (NTRS)

    Oren, J. A.; Duschatko, R. J.; Voss, F. E.; Sauer, L. W.

    1989-01-01

    Heat pipe with cylindrical heat-input surface has higher contact thermal conductance than one with usual flat surface. Cylindrical heat absorber promotes nearly uniform flow of heat into pipe at all places around periphery of pipe, helps eliminate hotspots on heat source. Lugs in aluminum pipe carry heat from outer surface to liquid oozing from capillaries of wick. Liquid absorbs heat, evaporates, and passes out of evaporator through interlug passages.

  15. Particle trap to sheath non-binding contact for a gas-insulated transmission line having a corrugated outer conductor

    DOEpatents

    Fischer, William H.

    1984-04-24

    A non-binding particle trap to outer sheath contact for use in gas insulated transmission lines having a corrugated outer conductor. The non-binding feature of the contact according to the teachings of the invention is accomplished by having a lever arm rotatably attached to a particle trap by a pivot support axis disposed parallel to the direction of travel of the inner conductor/insulator/particle trap assembly.

  16. Thermal Performance of High Temperature Titanium -- Water Heat Pipes by Multiple Heat Pipe Manufacturers

    NASA Technical Reports Server (NTRS)

    Sanzi, James L.

    2007-01-01

    Titanium - water heat pipes are being investigated for use in heat rejection systems for lunar and Mars fission surface power systems. Heat pipes provide an efficient and reliable means to transfer heat to a radiator heat rejection system. NASA Glenn Research Center requisitioned nine titanium water heat pipes from three vendors. Each vendor supplied three heat pipes 1.25 cm diameter by 1.1 meter long with each vendor selecting a different wick design. Each of the three heat pipes is slightly different in construction. Additional specifications for the heat pipes included 500 K nominal operating temperature, light weight, and freeze tolerance. The heat pipes were performance tested gravity-aided, in the horizontal position and at elevations against gravity at 450 K and 500 K. Performance of the three heat pipes is compared. The heat pipe data will be used to verify models of heat pipe radiators that will be used in future space exploration missions.

  17. Thermal Performance of High Temperature Titanium-Water Heat Pipes by Multiple Heat Pipe Manufacturers

    NASA Technical Reports Server (NTRS)

    Sanzi, James L.

    2007-01-01

    Titanium-water heat pipes are being investigated for use in heat rejection systems for lunar and Mars fission surface power systems. Heat pipes provide an efficient and reliable means to transfer heat to a radiator heat rejection system. NASA Glenn Research Center requisitioned nine titanium water heat pipes from three vendors. Each vendor supplied three heat pipes 1.25 cm diameter by 1.1 meter long with each vendor selecting a different wick design. Each of the three heat pipes is slightly different in construction. Additional specifications for the heat pipes included 500 K nominal operating temperature, light weight, and freeze tolerance. The heat pipes were performance tested gravity-aided, in the horizontal position and at elevations against gravity at 450 and 500 K. Performance of the three heat pipes is compared. The heat pipe data will be used to verify models of heat pipe radiators that will be used in future space exploration missions.

  18. Evanescent waves propagation along a periodically corrugated surface and their amplification by relativistic electron beam (quasi-optical theory)

    SciTech Connect

    Ginzburg, N. S.; Malkin, A. M.; Zheleznov, I. V.; Sergeev, A. S.

    2013-06-15

    By using a quasi-optical approach, we study propagation of evanescent waves along a periodically corrugated surface and their excitation by relativistic electron beams. Under assumption of a shallow (in the scale of period) corrugation, the dispersion equation for normal waves is derived and two particular cases are studied. In the first case, the wave frequency is far from the Bragg resonance; therefore, the evanescent wave propagation can be described by using the impedance approximation with deceleration of the zeroth spatial harmonic. The second case takes place at the frequencies close to the Bragg resonance. There, the field can be represented as two counter-propagating quasi-optical wave beams, which are coupled on the corrugated surface and form an evanescent normal wave. With regard to the interaction with an electron beam, the first case corresponds to the convective instability that can be used for amplification of radiation, while the second case corresponds to the absolute instability used in surface-wave oscillators. This paper is focused on studying main features of amplifier schemes, such as the increments, electron efficiency, and formation of a self-consistent spatial structure of the radiated field. For practical applications, the feasibility of realization of relativistic surface-wave amplifiers in the submillimeter wavelength range is estimated.

  19. Trend extraction of rail corrugation measured dynamically based on the relevant low-frequency principal components reconstruction

    NASA Astrophysics Data System (ADS)

    Li, Yanfu; Liu, Hongli; Ma, Ziji

    2016-10-01

    Rail corrugation dynamic measurement techniques are critical to guarantee transport security and guide rail maintenance. During the inspection process, low-frequency trends caused by rail fluctuation are usually superimposed on rail corrugation and seriously affect the assessment of rail maintenance quality. In order to extract and remove the nonlinear and non-stationary trends from original mixed signals, a hybrid model based ensemble empirical mode decomposition (EEMD) and modified principal component analysis (MPCA) is proposed in this paper. Compared with the existing de-trending methods based on EMD, this method first considers low-frequency intrinsic mode functions (IMFs) thought to be underlying trend components that maybe contain some unrelated components, such as white noise and low-frequency signal itself, and proposes to use PCA to accurately extract the pure trends from the IMFs containing multiple components. On the other hand, due to the energy contribution ratio between trends and mixed signals is prior unknown, and the principal components (PCs) decomposed by PCA are arranged in order of energy reduction without considering frequency distribution, the proposed method modifies traditional PCA and just selects relevant low-frequency PCs to reconstruct the trends based on the zero-crossing numbers (ZCN) of each PC. Extensive tests are presented to illustrate the effectiveness of the proposed method. The results show the proposed EEMD-PCA-ZCN is an effective tool for trend extraction of rail corrugation measured dynamically.

  20. Evaporation heat transfer and friction characteristics of R-134a flowing downward in a vertical corrugated tube

    SciTech Connect

    Aroonrat, Kanit; Wongwises, Somchai

    2011-01-15

    Differently from most previous studies, the heat transfer and friction characteristics of the pure refrigerant HFC-134a during evaporation inside a vertical corrugated tube are experimentally investigated. The double tube test sections are 0.5 m long with refrigerant flowing in the inner tube and heating water flowing in the annulus. The inner tubes are one smooth tube and two corrugated tubes, which are constructed from smooth copper tube of 8.7 mm inner diameter. The test runs are performed at evaporating temperatures of 10, 15, and 20 C, heat fluxes of 20, 25, and 30 kW/m{sup 2}, and mass fluxes of 200, 300, and 400 kg/m{sup 2} s. The quality of the refrigerant in the test section is calculated using the temperature and pressure obtained from the experiment. The pressure drop across the test section is measured directly by a differential pressure transducer. The effects of heat flux, mass flux, and evaporation temperature on the heat transfer coefficient and two-phase friction factor are also discussed. It is found that the percentage increases of the heat transfer coefficient and the two-phase friction factor of the corrugated tubes compared with those of the smooth tube are approximately 0-10% and 70-140%, respectively. (author)

  1. 46 CFR 197.336 - Pressure piping.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Pressure piping. 197.336 Section 197.336 Shipping COAST... GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.336 Pressure piping. Piping systems that are not an integral part of the vessel or facility, carrying fluids under pressures exceeding 15...

  2. 46 CFR 197.336 - Pressure piping.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Pressure piping. 197.336 Section 197.336 Shipping COAST... GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.336 Pressure piping. Piping systems that are not an integral part of the vessel or facility, carrying fluids under pressures exceeding 15...

  3. 46 CFR 197.336 - Pressure piping.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Pressure piping. 197.336 Section 197.336 Shipping COAST... GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.336 Pressure piping. Piping systems that are not an integral part of the vessel or facility, carrying fluids under pressures exceeding 15...

  4. 46 CFR 197.336 - Pressure piping.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Pressure piping. 197.336 Section 197.336 Shipping COAST... GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.336 Pressure piping. Piping systems that are not an integral part of the vessel or facility, carrying fluids under pressures exceeding 15...

  5. 46 CFR 197.336 - Pressure piping.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Pressure piping. 197.336 Section 197.336 Shipping COAST... GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.336 Pressure piping. Piping systems that are not an integral part of the vessel or facility, carrying fluids under pressures exceeding 15...

  6. 46 CFR 56.10-5 - Pipe.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... design limits of stress and temperature indicated in ASME B31.1 (incorporated by reference; see 46 CFR 56...-22 of this chapter.) (c) Nonferrous pipe. (See also § 56.60-20.) (1) Copper and brass pipe for water... temperatures to 406 °F. (2) Copper and brass pipe for air may be used in accordance with the allowable...

  7. 49 CFR 195.112 - New pipe.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false New pipe. 195.112 Section 195.112 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... PIPELINE Design Requirements § 195.112 New pipe. Any new pipe installed in a pipeline system must...

  8. 49 CFR 195.112 - New pipe.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false New pipe. 195.112 Section 195.112 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... PIPELINE Design Requirements § 195.112 New pipe. Any new pipe installed in a pipeline system must...

  9. 49 CFR 192.59 - Plastic pipe.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Plastic pipe. 192.59 Section 192.59 Transportation... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Materials § 192.59 Plastic pipe. (a) New plastic pipe... specification; and (2) It is resistant to chemicals with which contact may be anticipated. (b) Used plastic...

  10. 49 CFR 192.59 - Plastic pipe.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Plastic pipe. 192.59 Section 192.59 Transportation... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Materials § 192.59 Plastic pipe. (a) New plastic pipe... specification; and (2) It is resistant to chemicals with which contact may be anticipated. (b) Used plastic...

  11. 49 CFR 192.59 - Plastic pipe.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Plastic pipe. 192.59 Section 192.59 Transportation... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Materials § 192.59 Plastic pipe. (a) New plastic pipe... specification; and (2) It is resistant to chemicals with which contact may be anticipated. (b) Used plastic...

  12. 49 CFR 192.59 - Plastic pipe.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Plastic pipe. 192.59 Section 192.59 Transportation... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Materials § 192.59 Plastic pipe. (a) New plastic pipe... specification; and (2) It is resistant to chemicals with which contact may be anticipated. (b) Used plastic...

  13. 49 CFR 192.59 - Plastic pipe.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Plastic pipe. 192.59 Section 192.59 Transportation... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Materials § 192.59 Plastic pipe. (a) New plastic pipe... specification; and (2) It is resistant to chemicals with which contact may be anticipated. (b) Used plastic...

  14. Thermodynamic aspects of heat pipe operation

    NASA Technical Reports Server (NTRS)

    Richter, Robert; Gottschlich, Joseph

    1990-01-01

    An expanded heat pipe operating model is described which includes thermodynamic and heat transfer considerations to reconcile disparities between actual and theoretical heat pipe performances. The analysis shows that thermodynamic considerations can explain the observed heat pipe performance limitations. A full understanding of thermodynamic processes could lead to advanced concepts for thermal transport devices.

  15. 46 CFR 169.652 - Bilge piping.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... is such that ordinary leakage can be removed this way. (b) The bilge pipe on vessels 65 feet in length and under must be not less than one inch nominal pipe size. On vessels greater than 65 but less... area not less than three times the area of the bilge pipe. (d) Each individual bilge suction line...

  16. 46 CFR 169.652 - Bilge piping.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... is such that ordinary leakage can be removed this way. (b) The bilge pipe on vessels 65 feet in length and under must be not less than one inch nominal pipe size. On vessels greater than 65 but less... area not less than three times the area of the bilge pipe. (d) Each individual bilge suction line...

  17. 46 CFR 169.652 - Bilge piping.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... is such that ordinary leakage can be removed this way. (b) The bilge pipe on vessels 65 feet in length and under must be not less than one inch nominal pipe size. On vessels greater than 65 but less... area not less than three times the area of the bilge pipe. (d) Each individual bilge suction line...

  18. 46 CFR 108.447 - Piping.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Piping. 108.447 Section 108.447 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Fire Extinguishing Systems Fixed Carbon Dioxide Fire Extinguishing Systems § 108.447 Piping. (a) Each pipe,...

  19. 46 CFR 193.15-15 - Piping.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... carbon dioxide or other inert gas shall be used for this test. (2) The piping from the cylinders to the..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS FIRE PROTECTION EQUIPMENT Carbon Dioxide and Clean Agent Extinguishing Systems, Details § 193.15-15 Piping. (a) The piping, valves,...

  20. 46 CFR 193.15-15 - Piping.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... carbon dioxide or other inert gas shall be used for this test. (2) The piping from the cylinders to the..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS FIRE PROTECTION EQUIPMENT Carbon Dioxide and Clean Agent Extinguishing Systems, Details § 193.15-15 Piping. (a) The piping, valves,...

  1. 46 CFR 108.447 - Piping.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Piping. 108.447 Section 108.447 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Fire Extinguishing Systems Fixed Carbon Dioxide Fire Extinguishing Systems § 108.447 Piping. (a) Each pipe,...

  2. 46 CFR 95.17-15 - Piping.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Piping. 95.17-15 Section 95.17-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS FIRE PROTECTION EQUIPMENT Foam Extinguishing Systems, Details § 95.17-15 Piping. (a) All piping, valves, and fittings shall meet the...

  3. 46 CFR 76.17-15 - Piping.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 3 2011-10-01 2011-10-01 false Piping. 76.17-15 Section 76.17-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS FIRE PROTECTION EQUIPMENT Foam Extinguishing Systems, Details § 76.17-15 Piping. (a) All piping, valves, and fittings shall meet the...

  4. 46 CFR 95.17-15 - Piping.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Piping. 95.17-15 Section 95.17-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS FIRE PROTECTION EQUIPMENT Foam Extinguishing Systems, Details § 95.17-15 Piping. (a) All piping, valves, and fittings shall meet the...

  5. 46 CFR 95.17-15 - Piping.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Piping. 95.17-15 Section 95.17-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS FIRE PROTECTION EQUIPMENT Foam Extinguishing Systems, Details § 95.17-15 Piping. (a) All piping, valves, and fittings shall meet the...

  6. 46 CFR 76.17-15 - Piping.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 3 2012-10-01 2012-10-01 false Piping. 76.17-15 Section 76.17-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS FIRE PROTECTION EQUIPMENT Foam Extinguishing Systems, Details § 76.17-15 Piping. (a) All piping, valves, and fittings shall meet the...

  7. 46 CFR 95.17-15 - Piping.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Piping. 95.17-15 Section 95.17-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS FIRE PROTECTION EQUIPMENT Foam Extinguishing Systems, Details § 95.17-15 Piping. (a) All piping, valves, and fittings shall meet the...

  8. 46 CFR 76.17-15 - Piping.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 3 2010-10-01 2010-10-01 false Piping. 76.17-15 Section 76.17-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS FIRE PROTECTION EQUIPMENT Foam Extinguishing Systems, Details § 76.17-15 Piping. (a) All piping, valves, and fittings shall meet the...

  9. 46 CFR 95.17-15 - Piping.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Piping. 95.17-15 Section 95.17-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS FIRE PROTECTION EQUIPMENT Foam Extinguishing Systems, Details § 95.17-15 Piping. (a) All piping, valves, and fittings shall meet the...

  10. 46 CFR 76.17-15 - Piping.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 3 2013-10-01 2013-10-01 false Piping. 76.17-15 Section 76.17-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS FIRE PROTECTION EQUIPMENT Foam Extinguishing Systems, Details § 76.17-15 Piping. (a) All piping, valves, and fittings shall meet the...

  11. 46 CFR 76.17-15 - Piping.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 3 2014-10-01 2014-10-01 false Piping. 76.17-15 Section 76.17-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS FIRE PROTECTION EQUIPMENT Foam Extinguishing Systems, Details § 76.17-15 Piping. (a) All piping, valves, and fittings shall meet the...

  12. 46 CFR 76.33-15 - Piping.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS FIRE PROTECTION EQUIPMENT Smoke Detecting System, Details § 76.33-15 Piping. (a) Individual pipes shall be not less than 3/4-inch standard pipe... tank and the detecting cabinet so that the line may be shut off when liquids are carried. When...

  13. Bag Test Measures Leakage From Insulated Pipe

    NASA Technical Reports Server (NTRS)

    Schock, Kent D.; Easter, Barry P.

    1994-01-01

    Test quantifies leakage of gas from pipe even though pipe covered with insulation. Involves use of helium analyzer to measure concentration of helium in impermeable bag around pipe. Test administered after standard soap-solution bubble test indicates presence and general class of leakage.

  14. 49 CFR 236.712 - Brake pipe.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Brake pipe. 236.712 Section 236.712 Transportation... OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.712 Brake pipe. A pipe running from the engineman's brake valve through the train, used for the transmission of air...

  15. 49 CFR 236.712 - Brake pipe.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Brake pipe. 236.712 Section 236.712 Transportation... OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.712 Brake pipe. A pipe running from the engineman's brake valve through the train, used for the transmission of air...

  16. 49 CFR 236.712 - Brake pipe.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Brake pipe. 236.712 Section 236.712 Transportation... OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.712 Brake pipe. A pipe running from the engineman's brake valve through the train, used for the transmission of air...

  17. 49 CFR 236.712 - Brake pipe.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Brake pipe. 236.712 Section 236.712 Transportation... OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.712 Brake pipe. A pipe running from the engineman's brake valve through the train, used for the transmission of air...

  18. 49 CFR 236.712 - Brake pipe.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Brake pipe. 236.712 Section 236.712 Transportation... OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.712 Brake pipe. A pipe running from the engineman's brake valve through the train, used for the transmission of air...

  19. Heat pipes and their use in technology

    NASA Technical Reports Server (NTRS)

    Vasilyev, L.

    1977-01-01

    Heat pipes may be employed as temperature regulators, heat diodes, transformers, storage batteries, or utilized for transforming thermal energy into mechanical, electric, or other forms of energy. General concepts were established for the analysis of the transfer process in heat pipes. A system of equations was developed to describe the thermodynamics of steam passage through a cross section of a heat pipe.

  20. 46 CFR 154.660 - Pipe welding.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Pipe welding. 154.660 Section 154.660 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR... § 154.660 Pipe welding. (a) Pipe welding must meet Part 57 of this chapter. (b) Longitudinal butt...