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1

78 FR 5715 - Construction and Maintenance-Culvert Pipe Selection  

Federal Register 2010, 2011, 2012, 2013

...Autonomy for Culvert Pipe Selection,'' requires the Secretary...culvert and storm sewer type selection to either: (a) Include...would have to fit into the natural and constructed environment...to State DOTs regarding the selection of culvert and storm...

2013-01-28

2

Safe end treatments for roadside drainage culverts  

E-print Network

-of-control vehicle. The culvert installations tested were a corrugated metal pipe culvert and a concrete box culvert. Tests were conducted in accordance with nationally recognized test procedures, and the results were eval- uated based on the impact performance... with a 1971 Vega, 20 mph 7 Plan View of Preliminary Culvert Test Pit for Test 1 8 Culvert Test Pit, Test 1 9 Plan View of Site for Test 1 10 Corrugated Metal Pipe Culvert Test Pit Setup for Simulation of Nongrated Culvert 12 1974 Honda Civic, Test...

Jackson, Benito

2012-06-07

3

Corrugated pipe adhesive applicator apparatus  

DOEpatents

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.

Shirey, Ray A. (North Grafton, MA)

1983-06-14

4

Culvert pipe materials and durability: Making the right  

E-print Network

Manual (Chapter 2) #12;What causes pipes to deteriorate? · Acidity/alkalinity of water and soil (pH) · Soil resistivity · Chlorides & Sulfates · Abrasion · Loading (structural, freeze/thaw, bedding) #12.armtec.com/en-ca/products-and-services/drainage-solutions- and-water-treatment/hdpe-pipe/boss-2000.aspx #12;Databases Investigation · NRCS Web Soil Survey (WSS

Minnesota, University of

5

Terahertz Radiation from a Pipe with Small Corrugations  

SciTech Connect

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.

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

2012-01-26

6

Surface Impedance Formalism for a Metallic Beam Pipe with Small Corrugations  

SciTech Connect

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.

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

2012-08-30

7

On whistling of pipes with a corrugated segment: Experiment and theory  

NASA Astrophysics Data System (ADS)

Corrugated pipes are commonly used because of their local rigidity combined with global flexibility. The flow through such a pipe can induce strong whistling tones, which is an environmental nuisance and can be a threat to the mechanical integrity of the system. This paper considers the use of a composite pipe: a shorter corrugated pipe segment embedded between smooth pipe segments. Such a pipe retains some flexibility, while the acoustical damping in the smooth pipe reduces whistling tones. Whistling is the result of coherent vortex shedding at the cavities in the wall. This vortex shedding is synchronized by longitudinal acoustic waves traveling along the pipe. The acoustic waves trigger the vortex shedding, which reinforces the acoustic field for a critical range of the Strouhal number values. A linear theory for plane wave propagation and the sound production is proposed, which allows a prediction of the Mach number at the threshold of whistling in such pipes. A semi-empirical approach is chosen to determine the sound source in this model. This source corresponds to a fluctuating force acting on the fluid as a consequence of the vortex shedding. The functional form of the Strouhal number dependency of the dimensionless sound source amplitude is based on numerical simulations. The magnitude of the source and the Strouhal number range in which it can drive whistling are determined by matching the model to results for a specific corrugated pipe segment length. This semi-empirical source model is then applied to composite pipes with different corrugated segment lengths. In addition, the effect of inlet acoustical convective losses due to flow separation is considered. The Mach number at the threshold of whistling is predicted within a factor 2.

Rudenko, Oleksii; Nakibo?lu, Gne?; Holten, Ad; Hirschberg, Avraham

2013-12-01

8

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

NASA Astrophysics Data System (ADS)

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.

Qingbang, Han; Ling, Chen; Changping, Zhu

2014-02-01

9

Experimental demonstration of energy-chirp control in relativistic electron bunches using a corrugated pipe.  

PubMed

The first experimental study is presented of a corrugated wall device that uses wakefields to remove a linear energy correlation in a relativistic electron beam (a "dechirper"). Time-resolved measurements of both longitudinal and transverse wakefields of the device are presented and compared with simulations. This study demonstrates the feasibility to employ a dechirper for precise control of the beam phase space in the next generation of free-electron-lasers. PMID:24484143

Emma, P; Venturini, M; Bane, K L F; Stupakov, G; Kang, H-S; Chae, M S; Hong, J; Min, C-K; Yang, H; Ha, T; Lee, W W; Park, C D; Park, S J; Ko, I S

2014-01-24

10

Best Practices for Quality Management of Stormwater Pipe Construction.  

National Technical Information Service (NTIS)

Stormwater pipe systems are integral features of transportation construction projects. Pipe culverts direct stormwater away from roadway structures and towards designated discharge areas. The improper installation of a pipe culvert can result in costly re...

L. Ptschelinzew, R. E. Minchin, R. R. Issa, Y. Zhang

2014-01-01

11

Singing Corrugated Pipes.  

ERIC Educational Resources Information Center

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)

Cadwell, Louis H.

1994-01-01

12

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...

13

Culvert Testing Program for Juvenile Salmonid Passage  

SciTech Connect

In partnership with the Washington State Department of Transportation (WSDOT), the Pacific Northwest National Laboratory (PNNL) has undertaken a phased program conducted by an interdisciplinary team of experts to address the hydraulic and behavioral issues associated with juvenile salmonid fish passage through culvert systems. Juvenile coho salmon (Oncorhynchus kisutch) is the initial test subject. This program addresses the testing and assessment of culvert designs, along with associated measurements of hydraulic conditions and fish behavior, occurring in full-scale physical models of culvert systems deployed in an experimental test bed. The proposed approach includes the use of three kinds of models. First, a conceptual model of fish passage is developed to guide the design of hydraulic and behavioral testing and to interpret the results. Second, mathematical models of culvert hydraulics provide information to design the full-scale test facility and to guide design of the hydraulic a nd behavioral testing program. Third, full-scale physical models of culverts in a test bed are used to evaluate fish passage quantitatively. Using the knowledge and data from previous studies, this program will encompass the design, fabrication, installation, and operation of a full-scale, controlled culvert test bed. Experiments in the testing apparatus will measure the hydraulic conditions (mean velocity, turbulence, and water depth) associated with various culvert designs under various slopes and flow regimes and then relate these measures to repeatable, quantitative measures of fish passage success. After construction in late spring, 2001, preliminary trials will be conducted in summer 2001.

Pearson, Walter H. (BATTELLE (PACIFIC NW LAB)); Richmond, Marshall C. (BATTELLE (PACIFIC NW LAB)); Schafer, Jim (Washington State Department of Transportation)

2002-01-01

14

Development of advanced design, insulation, and installation practices for hot water district heating piping  

Microsoft Academic Search

In the first part of this paper, some of the newest design features of hot water district heating piping are described. Emphasis is on polyurethane preinsulated one- and two-pipe elements equipped with a polyethylene jacket pipe. The paper also deals with the newest developments in concrete culvert district heating lines, namely the preinsulated concrete culvert pipe elements with a metal

Huovilainen

1983-01-01

15

Birefringent corrugated waveguide  

Microsoft Academic Search

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

Charles P

1990-01-01

16

Birefringent corrugated waveguide  

Microsoft Academic Search

A corrugated waveguide having a circular bore and noncircularly symmetric corrugations, and preferably elliptical corrugations, provides birefringence for rotation of polarization in the HE mode. The corrugated waveguide may be fabricated by cutting circular grooves on a lathe in a cylindrical tube or rod of aluminium of a diameter suitable for the bore of the waveguide, and then cutting an

1989-01-01

17

Birefringent corrugated waveguide  

Microsoft Academic Search

This patent describes a corrugated waveguide having a circular bore and noncircularly symmetric corrugations, and preferably elliptical corrugations which provides birefringence for rotation of polarization in the HE 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,

1990-01-01

18

3. View southwest at dewatered culvert outlet headwall, with part ...  

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

3. View southwest at dewatered culvert outlet headwall, with part of canal bank removed in back (left) of headwall. - Delaware & Raritan Canal, Ten Mile Run Culvert, 1.5 miles South of Blackwells Road, East Millstone, Somerset County, NJ

19

4. View southeast at culvert outlet with part of the ...  

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

4. View southeast at culvert outlet with part of the canal bank removed. Right to left: dewatered streambed and coffer dam; tops of culvert barrels and curved wingwalls exposed; horizontal masonry cutoff wall partially up the canal bank. - Delaware & Raritan Canal, Six Mile Run Culvert, .2 mile South of Blackwells Mills Road, East Millstone, Somerset County, NJ

20

Using Flexible Pipe (poly-pipe) with Surface Irrigation  

E-print Network

out (Fig. 2). roll of poly-pipe is needed, connect the rolls with a corrugated pipe (Figs. 5a, 5b and 5c). Be sure to roll each end back on itself (as previously described) be- fore strapping it to the supply pipe (Fig. 4a). Figure 2. Poly-pipe set... rubber straps to connect the poly-pipe to the supplying pipe. Figure 5a. Connecting two rolls of poly-pipe. Figure 5b. Using a corrugated PVC pipe to connect two rolls of poly-pipe. Figure 5c. Making a tight con- nection to avoid water leaks. Figure 3...

Peries, Xavier; Enciso, Juan

2005-10-05

21

Cleaning process for corrugated aluminum electrical transmission line enclosure  

DOEpatents

A process for preparing the interior of a corrugated pipe or sheath comprises the steps of placing a predetermined amount of a tumbling abrasive material into the sheath, and then rotating the sheath.

Bowman, Gary K. (Westborough, MA)

1984-07-24

22

Birefringent corrugated waveguide  

SciTech Connect

This patent describes a corrugated waveguide having a circular bore and noncircularly symmetric corrugations, and preferably elliptical corrugations which 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 {minus} 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.

Moeller, C.P.

1990-03-06

23

Curved cap corrugated sheet  

NASA Technical Reports Server (NTRS)

The report describes a structure for a strong, lightweight corrugated sheet. The sheet is planar or curved and includes a plurality of corrugation segments, each segment being comprised of a generally U-shaped corrugation with a part-cylindrical crown and cap strip, and straight side walls and with secondary corrugations oriented at right angles to said side walls. The cap strip is bonded to the crown and the longitudinal edge of said cap strip extends beyond edge at the intersection between said crown and said side walls. The high strength relative to weight of the structure makes it desirable for use in aircraft or spacecraft.

Davis, R. C.; Bales, T. T.; Royster, D. M.; Jackson, L. R. (inventors)

1984-01-01

24

Incipient motion of gravel in a bottomless arch culvert  

Microsoft Academic Search

Incipient motion was investigated for four gravel substrate materials in a bottomless arch culvert and a rectangular flume. Different methods for calculating Shields parameter at incipient motion (?c) based upon local flow parameters were explored. An incipient motion region for bottomless arch culverts in fully turbulent flow was defined with two bounding curves on Shields diagram. The variation of ?c

B. M. CROOKSTON; B. P. M. TULLIS

2011-01-01

25

1. View southeast at northwest facade of dewatered culvert outlet ...  

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

1. View southeast at northwest facade of dewatered culvert outlet headwall, above which part of the canal bank has been removed. Buttresses and upper portion of headwall (above arches) are nineteenth-century additions to the lower, original headwall. - Delaware & Raritan Canal, Ten Mile Run Culvert, 1.5 miles South of Blackwells Road, East Millstone, Somerset County, NJ

26

7. View north at back (canal side) of culvert inlet, ...  

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

7. View north at back (canal side) of culvert inlet, with canal bank completely removed. Background to foreground: back of inlet headwall with tops of high inlet barrels exposed; vertical transition wall between high inlet barrels and low, interior, inlet barrels; tops of low interior barrels; vertical heartening planks and low cutoff wall at site of former canal edge of canal bank; dewatered canal bed and plank sheathing on top of culvert barrels beneath canal bed. - Delaware & Raritan Canal, Ten Mile Run Culvert, 1.5 miles South of Blackwells Road, East Millstone, Somerset County, NJ

27

Drainage culverts as habitat linkages and factors affecting passage by mammals  

Microsoft Academic Search

Summary 1. Drainage culverts are ubiquitous features in road corridors, yet little is known about the efficacy of culverts for increasing road permeability and habitat connectivity for terrestrial wildlife. Culvert use by small- and medium-sized mammals was investigated along roads in Banff National Park, Alberta, Canada. An array of culvert types was sampled varying in dimensions, habitat and road features

Anthony P. Clevenger; Bryan Chruszcz; Kari Gunson

2001-01-01

28

pipes  

Microsoft Academic Search

The aim of this paper is to present a kinetic numerical scheme for the computations of transient pressurised flows in closed water pipes. Firstly, we detail the mathematical model written as a conservative hyperbolic partial differentiel system of equations, and then we recall how to obtain the corresponding kinetic formulation. Then we build the kinetic scheme ensuring an upwinding of

C. Bourdarias; S. Gerbi

29

7. EAST PORTAL OF CONCRETE LINED CULVERT LOCATED 30 YARDS ...  

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

7. EAST PORTAL OF CONCRETE LINED CULVERT LOCATED 30 YARDS WEST OF HAPPY ISLES BRIDGE. NOTE ROCK & CONCRETE FLOOR. - Happy Isles Bridge, Spanning Merced River on Service road, Yosemite Village, Mariposa County, CA

30

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

31

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

32

Autonomous quadrotor unmanned aerial vehicle for culvert inspection  

E-print Network

This document presents work done to lay the foundation for an Unmanned Aerial Vehicle (UAV) system for inspecting culverts. By expanding upon prior progress creating an autonomous indoor quadrotor, many basic hardware and ...

Serrano, Nathan E

2011-01-01

33

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

34

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

35

7. OBLIQUE VIEW OF CULVERT UNDER LATROBE ROAD WEST OF ...  

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

7. OBLIQUE VIEW OF CULVERT UNDER LATROBE ROAD WEST OF THE WHITE ROCK RD. INTERSECTION; VIEW TO SOUTHWEST. - Placerville Road, White Rock Road between Clarksville & White Rock, El Dorado Hills, El Dorado County, CA

36

6. View southwest, culvert inlet with canal bank completely removed. ...  

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

6. View southwest, culvert inlet with canal bank completely removed. Left to right: back of headwall; tops of high inlet barrels; vertical transition wall between high inlet barrels and low, interior, inlet barrels; tops of low interior barrels; vertical heartening planks and low cutoff wall along former edge of canal bank; dewatered canal bed. - Delaware & Raritan Canal, Ten Mile Run Culvert, 1.5 miles South of Blackwells Road, East Millstone, Somerset County, NJ

37

Towards effective culvert design: monitoring seasonal use and behavior by Mediterranean mesocarnivores.  

PubMed

Drainage culverts are known to be used by a diverse number of species. To date, most studies looking at culvert usage have been restricted to the dry season. This seasonal bias has limited our understanding of how different species respond to culverts and, consequently, our ability to find effective ways to promote the use of culverts as aids to species movement. The main goal of this study was to examine the role of highway culverts for mesocarnivores throughout the year. We addressed (1) the seasonality of culvert use, (2) the relative importance of culvert structure, highway features, and surrounding landscape on culvert use, (3) the influence of the water depth and cover on culvert use, and (4) the effect of culvert structure on individual behavior. Fifteen culverts were monitored along 2 highways in southern Portugal using video-surveillance cameras and marble dust for 10 consecutive days per season. We used generalized linear mixed models to determine which factors most affected the culvert use and behavior by mesocarnivores. Our results highlight the effect of seasonality and water on culvert use. Culvert use was positively related with species activity throughout the year. All species (except otters (Lutra lutra)) were less likely to use culverts that contained water more than 3cm deep or covering more than 70% of the culvert base. Based on our results, future surveys and culvert retrofit design should address (1) the importance of seasonality in the interpretation of results and (2) the complementarity of culvert-specific features (water, ledges, and naturalization). PMID:23208760

Serronha, Ana Marta; Mateus, Ana Rita Amaro; Eaton, Finn; Santos-Reis, Margarida; Grilo, Clara

2013-08-01

38

Feasibility of culvert IED detection using thermal neutron activation  

NASA Astrophysics Data System (ADS)

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.

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

2012-06-01

39

Dielectric corrugated for millimeter wave applications  

Microsoft Academic Search

An antenna structure may be conveniently fabricated using a corrugated dielectric waveguide. A dielectric corrugated antenna has been designed and phase constants computed. By computing phase and decay constants for various corrugation thickness, corrugation period, and corrugation height, the radiation pattern can be plotted. The trapped corrugated antenna can have many useful applications. It can be used in the RF

S. C. Shrivastava; A. K. Tiwari

1989-01-01

40

Response of bull trout (Salvelinus confluentus) to habitat reconnection through replacement of hanging culverts with bridges  

Microsoft Academic Search

We examined the effectiveness of road culvert replacement on providing access to fish habitat in two tributary streams of the Torpy River, in central British Columbia. For both study streams, culverts had been \\

J. Mark Shrimpton; Christopher J. Cena; Adrian D. Clarke

41

Temporal and Spatial Quantification of Fine-Sediment Accumulation Downstream of Culverts in Brook Trout Habitat  

Microsoft Academic Search

We quantified fine-sediment accumulation annually from 2000 to 2003 after culvert construction in five Laurentian Shield streams containing brook trout Salvelinus fontinalis. A significant spatial pattern (section effect) was observed in which the accumulation was lowest upstream of the culvert (section 1), peaked in the section directly below the culvert (section 2), and slightly decreased in sections further downstream (sections

Stephanie Lachance; Maryse Dub; Renaud Dostie; Pierre Brub

2008-01-01

42

9. VIEW OF WHITE ROCK ROAD INDICATING CULVERT LOCATION (SEE ...  

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

9. VIEW OF WHITE ROCK ROAD INDICATING CULVERT LOCATION (SEE ROAD ANGLE POINT ON RIGHT) WITH LATROBE RD, INTERSECTION IN DISTANCE (LEFT OF CENTER); VIEW TO NORTHEAST. - Placerville Road, White Rock Road between Clarksville & White Rock, El Dorado Hills, El Dorado County, CA

43

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

44

An Improved Method of Manufacturing Corrugated Boxes: Lateral Corrugator  

SciTech Connect

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.

Frank C. Murray Ph.D.; , Roman Popil Ph.D.; Michael Shaepe (formerly with IPST, now at Cargill. Inc)

2008-12-18

45

Simulation of heat losses and ground temperatures for district-heating culverts. Comparison with field experiments for well-insulated, damaged, and extra-insulated culverts  

Microsoft Academic Search

Many old district-heating culverts are in bad condition due to the entry of water into the thermal insulation. The thermal conductivity, and thereby the heat loss from the culvert, is much larger for a wet than a dry thermal insulation. The high energy prices make it interesting and necessary to find the water-damaged parts of the district-heating culvert and improve

Hagentoft

1986-01-01

46

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

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.

Barringer, Thomas

1996-01-01

47

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

USGS Publications Warehouse

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

Bradley, D. Nathan

2013-01-01

48

330 GHz helically corrugated waveguide  

Microsoft Academic Search

Corrugated waveguide made with a tap can significantly lower fabrication costs. A 330 GHz, 19 mm i.d., 4.5 m long brass circular waveguide was tapped and tested. Transmission measurements were compared with models that take into account the shape of the corrugation.

Paul P. Woskov; Emilio A. Nanni; Michael A. Shapiro; Sudheer K. Jawla; Jason S. Hummelt; Richard J. Temkin; Alexander B. Barnes

2011-01-01

49

Review on rail corrugation studies  

Microsoft Academic Search

In Japan, rail corrugations had not been so serious formerly, but it began to be prevailing in recent years. In order to prevent the generation of rail corrugation, many studies have been reported in the world since the end of 19th century, but theories on them have not explained the formation mechanism perfectly and no perfect countermeasures have been established

Yoshihiko Sato; Akira Matsumoto; Klaus Knothe

2002-01-01

50

On-Site Wastewater Treatment Systems: Gravel-less Pipe  

E-print Network

of corrugated, perforated polyeth- ylene and is commercially available in 8- and 10-inch diameters. The pipe is wrapped with geotextile fabric. 3 Pipe trenches, which are 2 feet wide and no more than 150 feet long. In a gravel-less pipe system, wastewater flows... of corrugated, perforated polyeth- ylene and is commercially available in 8- and 10-inch diameters. The pipe is wrapped with geotextile fabric. 3 Pipe trenches, which are 2 feet wide and no more than 150 feet long. In a gravel-less pipe system, wastewater flows...

Lesikar, Bruce J.

2000-04-10

51

Assessment of Trout Passage through Culverts in a Large Montana Drainage during Summer Low Flow  

Microsoft Academic Search

We used a combination of methods to assess the degree of fish passage restriction from road culverts during summer low flow for westslope cutthroat trout Oncorhynchus clarkii lewisi and brook trout Salvelinus fontinalis across a large drainage basin. The FishXing fish passage model classified 41 of 45 (91%) culverts as barriers to upstream passage for 152-mm westslope cutthroat trout. Population

D. Drake Burford; Thomas E. McMahon; Joel E. Cahoon; Matthew Blank

2009-01-01

52

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 76 WEST (256). - Kings Canyon Road, Carson City, Carson City, NV

53

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

Code of Federal Regulations, 2011 CFR

... 2011-10-01 false Roadway, tunnels and subways, bridges and culverts, ties, rails, other track material, ballast...Structures 1242.15 Roadway, tunnels and subways, bridges and culverts, ties, rails, other track material,...

2011-10-01

54

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 false Roadway, tunnels and subways, bridges and culverts, ties, rails, other track material, ballast...Structures 1242.15 Roadway, tunnels and subways, bridges and culverts, ties, rails, other track material,...

2010-10-01

55

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...

56

Mass transfer in corrugated membranes  

NASA Astrophysics Data System (ADS)

Research on the chemical and physical structure of membranes has failed to overcome the inverse relationship between selectivity and permeability. While this permeability is partially responsible for the rate of separation, the geometry of the membrane contributes significantly to this rate. In this work, we focused on the system geometry by examining the effect of corrugations on the rate of membrane separations. We developed a theory to describe mass transport in corrugations and to predict the effectiveness of corrugated membranes. To verify this theory, membranes with millimeter-sized corrugations were made. Pervaporation experiments with highly permeable and less permeable solutes showed excellent agreement with the theory. Based on the membrane geometry and permeability, the effectiveness factor and the flux enhancement can be quantified by a modified Thiele analysis. We used this theory to examine the effect of small corrugations on the mass transfer of both liquids and gases across membranes, including the effects of free convection, membrane supports, and Knudsen diffusion. In systems with a liquid feed, corrugations are promising only for very impermeable solutes. In gases, corrugations are more effective, especially when supported by a porous structure. We attempted to make smaller corrugations in two ways. The more promising method is phase-inversion of diblock copolymers. These diblocks were dissolved in a solvent, made into a thin film, and immersed in a liquid that was a nonsolvent for the majority block and a solvent for the minority block. In this way, we attempted to draw the minority block to the surface of an undulating structure created by the phase inversion. Ideally, the minority block would be selective and the majority block would be highly permeable or porous. Scanning electron microscopy showed promising structures made from polystyrene-polyisoprene and polyacrylonitrile-polyethylene oxide. The other, less promising, attempt at making high surface area membranes used interfacial polymerization across a surfactant-templated interface. This surfactant template, which offers enhanced surface area, occurs in the bicontinuous surfactant-rich phase of a three-phase system. The permeability of control membranes made by typical interfacial polymerization was compared with the permeability of membranes made in microemulsions. The latter were compromised by defects.

Gronda, Ann Mclaughry

57

Bioinspired Corrugated Airfoil at Low Reynolds Numbers  

E-print Network

Bioinspired Corrugated Airfoil at Low Reynolds Numbers Hui Hu and Masatoshi Tamai Iowa State behavior around a bioinspired corrugated airfoil compared with a traditional streamlined airfoil and a flat of such bioinspired corrugated airfoils for micro air vehicle applications. The experiments were conducted in a low

Hu, Hui

58

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

SciTech Connect

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.

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

2001-10-30

59

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

ERIC Educational Resources Information Center

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

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

2011-01-01

60

Badger Roadkill Risk in Relation to the Presence of Culverts and Jersey Barriers  

Microsoft Academic Search

Abstract The subspecies of American badger,found in British Columbia,(Taxidea taxus jeffersonii) is provincially red-listed and nationally endangered.,The primary cause,of mortality is roadkill. Eur opean,badgers,(Melesmeles ) and other carnivores,are known to pass under highways using culverts, and there are indications that American badgers do also, suggesting,that the presence,of more culverts might be associated with lower roadkill risk for American badgers. Furthermore,

Trevor A. Kinley; Nancy J. Newhouse

2009-01-01

61

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

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.

Barringer, Thomas

1996-01-01

62

Biaxially corrugated flexible sheet material  

SciTech Connect

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.

Schmertz, John C. (5308 Ellsworth Ave., Pittsburgh, PA 15232)

1991-04-16

63

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

NASA Astrophysics Data System (ADS)

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.

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

2011-09-01

64

The characterization of tandem and corrugated wings  

NASA Astrophysics Data System (ADS)

Dragonfly wings have two distinct features: a tandem configuration and wing corrugation. Both features have been extensively studied with the aim to understand the superior flight performance of dragonflies. In this paper we review recent development of tandem and corrugated wing aerodynamics. With regards to the tandem configuration, this review will focus on wing/wing and wing/vortex interactions at different flapping modes and wing spacing. In addition, the aerodynamics of tandem wings under gusty conditions will be reviewed and compared with isolated wings to demonstrate the gust resistance characteristics of flapping wings. Regarding corrugated wings, we review their structural and aerodynamic characteristics.

Lian, Yongsheng; Broering, Timothy; Hord, Kyle; Prater, Russell

2014-02-01

65

Brownian transport in corrugated channels with inertia  

E-print Network

The transport of suspended Brownian particles dc-driven along corrugated narrow channels is numerically investigated in the regime of finite damping. We show that inertial corrections cannot be neglected as long as the width of the channel bottlenecks is smaller than an appropriate particle diffusion length, which depends on the the channel corrugation and the drive intensity. Being such a diffusion length inversely proportional to the damping constant, transport through sufficiently narrow obstructions turns out to be always sensitive to the viscosity of the suspension fluid. The inertia corrections to the transport quantifiers, mobility and diffusivity, markedly differ for smoothly and sharply corrugated channels.

P. K. Ghosh; P. Hanggi; F. Marchesoni; F. Nori; G. Schmid

2012-08-21

66

Casimir torque between corrugated metallic plates  

E-print Network

We consider two parallel corrugated plates and show that a Casimir torque arises when the corrugation directions are not aligned. We follow the scattering approach and calculate the Casimir energy up to second order in the corrugation amplitudes, taking into account nonspecular reflections, polarization mixing and the finite conductivity of the metals. We compare our results with the proximity force approximation, which overestimates the torque by a factor 2 when taking the conditions that optimize the effect. We argue that the Casimir torque could be measured for separation distances as large as 1 $\\mu{\\rm m}.$

Robson B. Rodrigues; Paulo A. Maia Neto; Astrid Lambrecht; Serge Reynaud

2007-10-30

67

Horn antenna with v-shaped corrugated surface  

NASA Technical Reports Server (NTRS)

Corrugated shape is easily machined for millimeter wave application and is better suited for folding antenna designs. Measured performance showed ""V'' corrugations and rectangular corrugations have nearly the same pattern beamwidth, gain, and impedance. Also, ""V'' corrugations have higher relative power loss.

Beck, F. B.; Mentzer, C. A.; Peters, L., Jr.

1975-01-01

68

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

69

Effects of Culverts on Stream Fish Assemblages in the Alberta Foothills  

Microsoft Academic Search

Watercourse-crossing structures are ubiquitous anthropogenic features in the Rocky Mountain foothills of Alberta. We performed physical and habitat assessments at 295 watercourse-crossing sites in 15 subbasins of the Athabasca River during the summer and early fall of 2007, 2008, and 2009, sampling for fish at 110 sites (32 bridges and 78 culverts). We used bootstrapping analysis to examine how several

Laura M. MacPherson; Michael G. Sullivan; A. Lee Foote; Cameron E. Stevens

2012-01-01

70

Method and apparatus for corrugating strips  

DOEpatents

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.

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

1981-10-27

71

Group index engineering in silicon corrugated waveguides  

Microsoft Academic Search

We present experimental measurements of the group index in tailored silicon corrugated waveguides. Nearly constant group index as high as ng=14 0.5 in a 13 nm range was measured in a 50 ?m long waveguide.

A. Brimont; A. Griol; J. Marti; P. Sanchis

2010-01-01

72

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

SciTech Connect

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.

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

2004-10-25

73

High frequency scattering from corrugated stratified cylinders  

NASA Technical Reports Server (NTRS)

Interest in applying radar remote sensing for the study of forested areas led to the development of a model for scattering from corrugated stratified dielectric cylinders. The model is used to investigate the effect of bark and its roughness on scattering from tree trunks and branches. The outer layer of the cylinder (bark) is assumed to be a low-loss dielectric material and to have a regular (periodic) corrugation pattern. The inner layers are treated as lossy dielectrics with smooth boundaries. A hybrid solution based on the moment method and the physical optics approximation is obtained. In the solution, the corrugations are replaced with polarization currents that are identical to those of the local tangential periodic corrugated surface, and the stratified cylinder is replaced with equivalent surface currents. New expressions for the equivalent physical-optics currents are used which are more convenient than the standard ones. It is shown that the bark layer and its roughness both reduce the radar cross-section. It is also demonstrated that the corrugations can be replaced by an equivalent anisotropic layer.

Sarabandi, Kamal; Ulaby, Fawwaz T.

1991-01-01

74

A numerically based design procedure for buried high-density polyethylene profile-wall pipes buried in fine-grained in-situ soils  

E-print Network

, an adequate design results since the plane- strai n assumption is conservative with respect to in-plane response. Non-uniform loads along the length of the pipe can cause longitudinal bending. This effect is minimized, however, by the corrugation found... wall per longitudinal unit length The basic concepts controlling the structural behavior of an unconfined pipe, as outlined by Katona ( 1), can be illustrated by CROWN SHOULDER ? ? - SPRINGLINE PIPE HAUNCH INVERT t SMOOTH-WALL IL CORRUGATED...

Brown, Frederick Allen

2012-06-07

75

The effects of construction on water quality: a case study of the culverting of Abram Creek  

Microsoft Academic Search

While sediment is a leading cause of impaired water, studies have shown that construction activities incorporating best management\\u000a practices (BMPs) can be conducted without lasting detrimental effects on water quality. This paper examines the water quality\\u000a impacts of a construction project involving the culverting of a creek to allow for the construction of a runway at an airport\\u000a in Cleveland,

Darci L. Houser; Heidi Pruess

2009-01-01

76

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

NASA Astrophysics Data System (ADS)

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.

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

2013-04-01

77

Dielectrically loaded corrugated waveguide - Variational analysis of a nonstandard eigenproblem  

Microsoft Academic Search

Motivated by simple fabricability, the dielectrically loaded corrugated waveguide is analyzed applying the theory of nonstandard eigenvalues and variational principles recently presented by one of the authors. The eigenvalue parameter of this problem is the boundary susceptance of the corrugated surface, which choice is seen to lead to a simple functinal. The functional is tested for the air-filled corrugated guide,

I. V. Lindell; A. H. Sihvola

1983-01-01

78

Variational Analysis of a Dielectrically Loaded Corrugated Waveguide  

Microsoft Academic Search

An easily fabricated type of corrugated waveguide is described and a variational method is applied for the calculation of its propagation properties. The stationary functional is of unusual type, because the boundary susceptance of the corrugated guide is conceived as a nonstandard eigenvalue of the problem. The resulting method is tested with an ordinary corrugated guide.

Ismo V. Lindell; Ari H. Sihvola

1982-01-01

79

CONTRIBUTION TO THE MODELLING OF THE CORRUGATED CARDBOARD BEHAVIOUR  

E-print Network

of the corrugated cardboard. The main tests are three or four points bending (ASTM C393-62), as well as shear testsCONTRIBUTION TO THE MODELLING OF THE CORRUGATED CARDBOARD BEHAVIOUR S. Allaoui* , Z. Aboura** and M The current paper summarizes studies undertaken on the corrugated cardboard. In these studies, a new approach

Boyer, Edmond

80

Study of five corrugated case designs  

E-print Network

The purpose of the research described in this thesis is to define the primary damages occurring to corrugated cases in the normal distribution system of Frito-Lay, Incorporated and compare the relative performance (to be defined in terms of trip...

Rogers, Roxanne Russell

2012-06-07

81

Plasmonic corrugated cylinder-cone terahertz probe.  

PubMed

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

Yao, Haizi; Zhong, Shuncong

2014-08-01

82

A 2-GHz Rectangular Corrugated Horn  

SciTech Connect

We have designed, constructed and tested a large, rectangular horn antenna with a center frequency of 2.0 GHz, corrugated on the E-plane walls, made out of aluminum sheet. A new technique has been developed to solder thin aluminum strips onto the back plane to form the corrugations. The radiation beam pattern shows half-power beamwidths of 12{sup 0} and 14{sup 0} in the H and E planes respectively, and side lobe response below -40 dB at angles greater than 50{sup 0} from horn axis. The measured return loss is less than -20 dB (VSWR < 1.22) between 1.7 and 2.3 GHz; insertion loss is less than 0.15 dB.

Bersanelli, M.; Bensadoun, M.; De Amici, Giovanni; Limon, M.; Smoot, George F.; Tanaka, S.; Witebsky, C.; Yamada, J.

1991-10-01

83

Double-corrugated metamaterial surfaces for broadband microwave absorption  

NASA Astrophysics Data System (ADS)

Double-corrugated metamaterial surfaces are proposed to achieve broadband absorbers in the microwave region. The principal corrugation having a long period is made of hypo-corrugated metal structures filled with a dielectric medium. It is shown that the incident electromagnetic wave with a certain frequency can be strongly absorbed by the corrugation region where the height is about ?/4, with ? being the corresponding wavelength in the dielectric. Assembling various heights of corrugations together to form a graded corrugation surface can excite many distinct absorption modes and their overlapping with each other results in a broadband absorption. We experimentally demonstrate a broadband metamaterial absorber with more than 80% absorbance in the frequency range of 7.22-18.0 GHz which agrees well with the numerical simulation.

Pang, Yongqiang; Cheng, Haifeng; Zhou, Yongjiang; Wang, Jun

2013-02-01

84

Practical piping handbook  

SciTech Connect

A reference book on pipes, pipe fitting, and pipe treatment in the petroleum and natural gas industries is presented. The contents include: standard piping terminology; piping codes and standards; pipe manufacturing sizes; metallic piping; non-metallic piping; lined and coated piping systems; pipe tracing and jacketing; fittings and flanges; piping connections; valves; pipe expansion devices; flexible piping; piping specialties; pipe supports and restraints; insulation for piping; shop fabrication of piping; field installation of piping; construction tools and equipment; nondestructive and destructive testing; pipe cleaning; and comparative piping costs. (JMT)

Mendel, O.

1981-01-01

85

Electromagnetohydrodynamic flow through a microparallel channel with corrugated walls  

NASA Astrophysics Data System (ADS)

In this paper a perturbation method is introduced to study the electromagnetohydrodynamic (EMHD) flow in a microparallel channel with slightly corrugated walls. The corrugations of the two walls are periodic sinusoidal waves of small amplitude either in phase or half-period out of phase, and the perturbation solutions of velocity and volume flow rate are obtained. Using numerical computation the effects of the corrugations on the flow are graphically analysed. The results show that the influence of corrugation on the flow decreases with Hartmann number. The phase difference of wall corrugations becomes unimportant when the wavenumber is greater than 3 or when the Hartmann number is greater than 4. With the increase in wavenumber, the decreasing effects of corrugations on the flow increase. When the wavenumber is smaller than the threshold wavenumber (it is a function of Hartmann number) and the wall corrugations are half-period out of phase, the corrugations can enhance the mean velocity of EMHD flow. However, the mean velocity is always decreased when the corrugations are in phase.

Buren, Mandula; Jian, Yongjun; Chang, Long

2014-10-01

86

Performance of zigzag corrugated furrows in Bolivia  

NASA Astrophysics Data System (ADS)

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 regard to the system organization and operation.

Roldn Caas, J.; Chipana, R.; Moreno-Prez, M. F.; Chipana, G.

2012-04-01

87

Multistable and morphing corrugated shell structures  

E-print Network

of a circle or ellipse [mJ Intrinsic coordinate along a path [mJ Local shell thickness [m J Unit tangent vector to a line Absolute local out-of-plane distor t ion of the shell [mJ Local coordinates in the shell , with ;; normal to the plane... average over the material area/length , generally interpreted as mean average over one corrugation First , second Bc. derivative with respect to time Value at first , second Bc. iterations of an algorithm Init ial state (of curvature) Geodesic value...

Norman, Alexander David

2009-06-09

88

Pipe Dreams.  

ERIC Educational Resources Information Center

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)

Milshtein, Amy

2002-01-01

89

Adhesively bonded steel corrugated core sandwich construction for marine applications  

Microsoft Academic Search

The aims of this research were to fabricate an adhesively bonded steel corrugated core sandwich construction suitable for marine applications and to investigate the performance characteristics and failure mechanisms in comparison with other methods of fabrication. Construction of steel corrugated core sandwich structures for the marine industry are shown to be viable using modern structural adhesives. These sandwich structures are

E. M. Knox; M. J. Cowling; I. E. Winkle

1998-01-01

90

Relating Temperature Dependence of Atom Scattering Spectra to Surface Corrugation  

E-print Network

Relating Temperature Dependence of Atom Scattering Spectra to Surface Corrugation W. W. Hayes of the surface corrugation can be directly related to the temperature dependence of atom scattering spectra atomic mass, piz is the surface-normal component of the incident momentum, TS is the temperature, k

Manson, Joseph R.

91

A study of plate heat transfer surfaces with corrugated fins  

Microsoft Academic Search

The present article gives the results of studies that were made in the Institute of Technical Thermal Physics of the Academy of Sciences of the Ukrainian SSSR on the heat transfer and hydraulic resistance of plate heat transfer surfaces with corrugated fins; the thermal, dimensional, weight and energy characteristics of surfaces with different kinds of corrugated fins were compared. The

Z. V. Tishchenko; N. D. Butskii

1971-01-01

92

Planar plasmonic terahertz waveguides based on periodically corrugated metal films  

Microsoft Academic Search

We demonstrate that a one-dimensional periodically corrugated metal film can be used to create planar terahertz (THz) waveguides. The periodic corrugation is in the form of rectangular blind holes (i.e. holes that do not completely perforate the metal film) that are fabricated using a multilayer construction. The approach allows for the creation of structures in which the hole depth can

Gagan Kumar; Shashank Pandey; Albert Cui; Ajay Nahata

2011-01-01

93

Variational analysis of dielectrically loaded multidepth corrugated waveguides  

Microsoft Academic Search

Propagation behavior in a multidepth corrugated waveguide is analyzed. The analysis is based on the theory of nonstandard eigenvalues and variational methods. The method is tested for an empty dual-depth corrugated waveguide, which results have been previously calculated in the literature by using surface-impedance and space harmonic methods. These methods are summarized. Also some space harmonic formulas are rederived into

M. I. Oskanen

1988-01-01

94

On using corrugated skins to carry shear in sandwich beams  

Microsoft Academic Search

A simplified approach is used to study the potential of using a corrugated skin in a sandwich to carry shear loads. Shear carrying capability is a major requirement for ship bottom panels, among other structures. The simplifications in the paper are quite major and in particular the corrugated skin is modeled as a conventional material with a homogenized stiffness. The

Matthew Kampner; Joachim L. Grenestedt

2008-01-01

95

A linear model for the corrugation of rails  

Microsoft Academic Search

A linear model for the corrugation of rails is described. The study of a transfer function between the initial wheel and rail roughness and the wear rate spectra in the contact patch is presented. Under some conditions, depending on mean creepages, wheelset and track parameters, the initial roughness on the rail is shown to degenerate into corrugation in some frequency

E. Tassilly; N. Vincent

1991-01-01

96

Refined nonlinear finite element models for corrugated fiberboards  

Microsoft Academic Search

A refined nonlinear finite element modeling approach is presented for the analysis of corrugated fiberboard material and structural systems. The anisotropic and nonlinear material stressstrain behavior of the linerboards and fluting medium layers of the corrugated fiberboard composite system is modeled using orthotropic material model with Hills anisotropic plasticity. Uniaxial tensile tests are conducted separately for the linear and medium

Rami Haj-Ali; Joonho Choi; Bo-Siou Wei; Roman Popil; Michael Schaepe

2009-01-01

97

Corrugated Quantum Well Infrared Photodetectors and Arrays  

NASA Technical Reports Server (NTRS)

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.

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

1999-01-01

98

Biased Brownian motion in extremely corrugated tubes.  

PubMed

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. PMID:22225392

Martens, S; Schmid, G; Schimansky-Geier, L; Hnggi, P

2011-12-01

99

Scheduling and Planning Software for Corrugation Process  

NASA Astrophysics Data System (ADS)

In this paper, we are interested in developing a software for production planning for the corrugation process. We particularly study the scheduling problem of paper roll feeding in the mills. In the real industry, many constraints are post in order to assign paper rolls to the mill roll stand while the factory has several goals to meet such as saving paper cost and balancing worker loads. Such problems are known to be a difficult problem. We develop a heuristic to find the schedule under the goals to minimize waste, to balance the roll switching, and minimize butt rolls. Then, the web-based application is developed to create such a schedule and simulate the schedule results to verify the solutions.

Chantrapornchai, C.; Sathapanawat, T.

100

Development of advanced design, insulation, and installation practices for hot water district heating piping  

SciTech Connect

In the first part of this paper, some of the newest design features of hot water district heating piping are described. Emphasis is on polyurethane preinsulated one- and two-pipe elements equipped with a polyethylene jacket pipe. The paper also deals with the newest developments in concrete culvert district heating lines, namely the preinsulated concrete culvert pipe elements with a metal sheet jacket. In the second part of the paper a method for calculating the economic optimization of preinsulated district heating lines is described. The term ''economic optimization'' means that the sum of investment costs, heat loss costs, and pumping costs of the line during a certain period are minimized when the maximum heat output of the line is known. The optimization program is designed to answer the following important questions: What are the optimum flow-pipe dimensions, how great is the optimum heat conductance (or insulation thickness), and how do various factors influence the results obtained. In the third part, installation practices for different pipeline systems are discussed. Emphasis is on compensating for thermal movements in pipelines. Also compensating or noncompensating methods are discussed. In conclusion, some test methods developed in Finland are presented. Also, Scandinavian and European cooperation and standardization work in the field of district heating is discussed.

Huovilainen, R.

1983-06-01

101

Fabrication of corrugated Ge-doped silica fibers.  

PubMed

We present a method of fabricating Ge-doped SiO2 fibers with corrugations around their full circumference for a desired length in the longitudinal direction. The procedure comprises three steps: hydrogenation of Ge-doped SiO2 fibers to increase photosensitivity, recording of Bragg gratings with ultraviolet light to achieve modulation of refractive index, and chemical etching. Finite-length, radially corrugated fibers may be used as couplers. Corrugated tapered fibers are used as high energy throughput probes in scanning near-field optical microscopy. PMID:22714512

Wrbel, P; Stefaniuk, T; Antosiewicz, T J; Libura, A; Nowak, G; Wejrzanowski, T; Andrzejczuk, M; Kurzyd?owski, K J; Jedrzejewski, K; Szoplik, T

2012-06-18

102

Demonstration of angle-dependent Casimir force between corrugations.  

PubMed

The normal Casimir force between a sinusoidally corrugated gold coated plate and a sphere was measured at various angles between the corrugations using an atomic force microscope. A strong dependence on the orientation angle of the corrugation is found. The measured forces were found to deviate from the proximity force approximation and are in agreement with the theory based on the gradient expansion including correlation effects of geometry and material properties. We analyze the role of temperature. The obtained results open new opportunities for control of the Casimir effect in micromechanical systems. PMID:23829717

Banishev, A A; Wagner, J; Emig, T; Zandi, R; Mohideen, U

2013-06-21

103

Thermal Stability of Corrugated Epitaxial Graphene Grown on Re(0001)  

NASA Astrophysics Data System (ADS)

We report on a novel approach to determine the relationship between the corrugation and the thermal stability of epitaxial graphene grown on a strongly interacting substrate. According to our density functional theory calculations, the C single layer grown on Re(0001) is strongly corrugated, with a buckling of 1.6 , yielding a simulated C 1s core level spectrum which is in excellent agreement with the experimental one. We found that corrugation is closely knit with the thermal stability of the C network: C-C bond breaking is favored in the strongly buckled regions of the moir cell, though it requires the presence of diffusing graphene layer vacancies.

Miniussi, E.; Pozzo, M.; Baraldi, A.; Vesselli, E.; Zhan, R. R.; Comelli, G.; Mente?, T. O.; Nio, M. A.; Locatelli, A.; Lizzit, S.; Alf, D.

2011-05-01

104

Propagation and radiation characteristics of a multimode corrugated waveguide feedhorn  

NASA Technical Reports Server (NTRS)

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.

Hoppe, D.

1985-01-01

105

Scholte-Stoneley waves on corrugated surfaces and on phononic crystal gratings  

E-print Network

Scholte-Stoneley waves on corrugated surfaces and on phononic crystal gratings R. P. Moiseyenkoa observed for periodically corrugated surfaces in contact with water, with the periodic corrugation allowing, recent studies on SSW have instead focused on corrugated surfaces. SSW have been studied in the 1980's

Boyer, Edmond

106

Heat Pipes  

NASA Technical Reports Server (NTRS)

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.

1991-01-01

107

Prediction of sound reflection by corrugated porous surfaces.  

PubMed

The coupled mode (CM) and finite-element methods (FEMs) are developed and used to predict the acoustic reflection coefficient of a semi-infinite porous medium with closely spaced two-dimensional (2D) periodical corrugations. These methods are also applied to predict the reflection coefficient of a periodic array of porous corrugations installed on an acoustically rigid surface. It is shown that the predictions by the both methods agree closely. The reflection coefficient and Brewster angle of total refraction for the corrugated semi-infinite medium predicted with these methods are compared against that predicted by the Biot/Tolstoy/Howe/Twersky and extended Twersky models. A similar analysis is carried out for porous corrugations set on a rigid backing. The behavior of the reflection coefficient and the pole in the expression for the reflection coefficient located close to grazing incidence is studied. PMID:21476627

Allard, J-F; Dazel, O; Gautier, G; Groby, J-P; Lauriks, W

2011-04-01

108

Backward wave oscillators for THz applications based on corrugated waveguide  

Microsoft Academic Search

Backward wave oscillators are among the most promising solutions for power generation at THz frequencies. Two 1 THz backward wave oscillators based on different topology of corrugated waveguide are compared by 3D particle-in-cell simulations.

Mauro Mineo; Claudio Paoloni

2011-01-01

109

Corrugated SOI Waveguide for Optimal Slow-Light Elements  

Microsoft Academic Search

We present the design and fabrication of a 1D periodic structure based on a conventional SOI waveguide with transversal corrugations. This structure is proposed as an optimal slow-light element working around 1550 nm

J. Garcia; P. Sanchis; A. Martinez; F. Cuesta-Soto; J. Blasco; A. Griol; J. Marti

2006-01-01

110

Optical modeling of laterally-corrugated ridge-waveguide gratings  

Microsoft Academic Search

The paper presents some model improvements for the optical simulation of laterally-corrugated ridge-waveguide distributed\\u000a feedback lasers. Simulation results are discussed and design principles for achieving single-longitudinal-mode operation are\\u000a outlined. The effects of the laterally-corrugated ridge geometry both on the coupling coefficient and on the Bragg wavelength\\u000a of different transverse modes are presented. The improved modeling has been used to design

Antti Laakso; Mihail Dumitrescu; Jukka Viheril; Jukka Karinen; Mikko Suominen; Markus Pessa

2008-01-01

111

Low-loss broadband multimode corrugated waveguide performance  

Microsoft Academic Search

A 30-m-long waveguide run using circular corrugated waveguide (i.d.=6.35 cm) with a corrugated period and depth of 254 ?m (0.01 in.) has been fabricated and installed on TFTR (Tokamak Fusion Test Reactor) for use in electron cyclotron emission measurements, and is the first large scale application of this type of waveguide. It is designed for low-loss (<0.01 dB\\/m) multimode operation

A. Cavallo; J. Doane; R. Cutler

1990-01-01

112

Low Loss Broadband Multimode Circular Corrugated Waveguide Performance  

NASA Astrophysics Data System (ADS)

A 30 meter long circular corrugated waveguide run (i.d.=6.35 cm) with a corrugation period and depth of 250? has been fabricated. It is designed for low loss (<0.01 dB/m) multimode operation over the frequency range of 75-575 GHz. It will be installed on TFTR (Tokamak Fusion Test Reactor) for use in electron cyclotron emission measurements. Results will be compared to those obtained using conventional tall rectangular C-band waveguide.

Cavallo, A.; Doane, J.; Cutler, R.; Brenner, J.

1988-11-01

113

Piping Flexibility  

NASA Technical Reports Server (NTRS)

A NASA computer program aids Hudson Engineering Corporation, Houston, Texas, in the design and construction of huge petrochemical processing plants like the one shown, which is located at Ju'aymah, Saudi Arabia. The pipes handling the flow of chemicals are subject to a variety of stresses, such as weight and variations in pressure and temperature. Hudson Engineering uses a COSMIC piping flexibility analysis computer program to analyze stresses and unsure the necessary strength and flexibility of the pipes. This program helps the company realize substantial savings in reduced engineering time.

1978-01-01

114

Refrigerant piping  

SciTech Connect

The piping design of an air conditioning system is a critical element in the proper performance of the system. It involves an extremely complex relationship in the flow of refrigerant oil through the various parts of the system. The factor that must be considered in a piping design are the inter-relationships between velocity, pressure, friction and density, as well as the related variables required for proper fluid flow. These variables and relationships can be expressed in long mathematical equations, performance charts, and pressure drop tables for fluid flow through the piping. The improper design and sizing of refrigerant piping in a sealed system may result in loss of system efficiency that could lead to a los of overall system capacity as well as eventual failure of components of the system.

Puzio, H. [Sussex County Vocational Technical School, Sparta, NJ (United States)

1996-10-01

115

Aerodynamic Performances of Corrugated Dragonfly Wings at Low Reynolds Numbers  

NASA Astrophysics Data System (ADS)

The cross-sections of dragonfly wings have well-defined corrugated configurations, which seem to be not very suitable for flight according to traditional airfoil design principles. However, previous studies have led to surprising conclusions of that corrugated dragonfly wings would have better aerodynamic performances compared with traditional technical airfoils in the low Reynolds number regime where dragonflies usually fly. Unlike most of the previous studies of either measuring total aerodynamics forces (lift and drag) or conducting qualitative flow visualization, a series of wind tunnel experiments will be conducted in the present study to investigate the aerodynamic performances of corrugated dragonfly wings at low Reynolds numbers quantitatively. In addition to aerodynamics force measurements, detailed Particle Image Velocimetry (PIV) measurements will be conducted to quantify of the flow field around a two-dimensional corrugated dragonfly wing model to elucidate the fundamental physics associated with the flight features and aerodynamic performances of corrugated dragonfly wings. The aerodynamic performances of the dragonfly wing model will be compared with those of a simple flat plate and a NASA low-speed airfoil at low Reynolds numbers.

Tamai, Masatoshi; He, Guowei; Hu, Hui

2006-11-01

116

Detection of rail corrugation based on fiber laser accelerometers  

NASA Astrophysics Data System (ADS)

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.

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

2013-09-01

117

Stormwater Chemical Contamination Caused by Cured-in-Place Pipe (CIPP) Infrastructure Rehabilitation Activities.  

PubMed

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. PMID:25127182

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

2014-09-16

118

Quantitative nanofriction characterization of corrugated surfaces by atomic force microscopy  

NASA Astrophysics Data System (ADS)

Atomic force microscopy (AFM) is a suitable tool to perform tribological characterization of materials down to the nanometer scale. An important aspect in nanofriction measurements of corrugated samples is the local tilt of the surface, which affects the lateral force maps acquired with AFM. This is one of the most important problems of state-of-the-art nanotribology, hampering a reliable and quantitative characterization of real corrugated surfaces. In this article, we present a solution to the problem of the topographic correction of AFM lateral force maps acquired on corrugated samples in the presence of adhesion. We apply it in the specific case of multiasperity adhesive contacts, which are of common occurrence at many interfaces of technological interest. We discuss the validity and limitations of our approach.

Podest, A.; Fantoni, G.; Milani, P.

2004-05-01

119

Planar plasmonic terahertz waveguides based on periodically corrugated metal films  

NASA Astrophysics Data System (ADS)

We demonstrate that a one-dimensional periodically corrugated metal film can be used to create planar terahertz (THz) waveguides. The periodic corrugation is in the form of rectangular blind holes (i.e. holes that do not completely perforate the metal film) that are fabricated using a multilayer construction. The approach allows for the creation of structures in which the hole depth can be more than four times the hole width. This is necessary to achieve tightly confined THz guided-wave modes. We find that the modes can be modeled using an effective cavity resonance model and that the mode properties depend sensitively on the depth of corrugation. We use numerical simulations to validate the experimental results. We also highlight the differences between simulations that incorporate idealized input parameters and our experimental measurements. Using these data, we fabricate and characterize a Y-splitter to demonstrate the utility of this approach.

Kumar, Gagan; Pandey, Shashank; Cui, Albert; Nahata, Ajay

2011-03-01

120

Lateral Casimir force between deeply corrugated dielectric and metallic plates  

E-print Network

We study the lateral Casimir force between corrugated dielectric plates. We use the dielectric contrast perturbation theory [R. Golestanian, {\\it Phys. Rev. Lett.} {\\bf 95}, 230601, (2005)], which allows us to consider arbitrary deformations with large amplitudes. We consider sinusoidal, rectangular, and sawtooth corrugations, for samples made of silicon and gold. We use the plasma and Drude-Lorentz models for the permittivity of gold and silicon, respectively. For these geometries and materials, the lateral Casimir force is {\\it not} a sinusoidal function of the relative lateral displacement of plates when the gap between the plates in comparable with the depth of the corrugations. Our results facilitate the design of miniaturized devices based on lateral Casimir forces.

Arash Azari; MirFaez Miri

2014-09-16

121

Opportunities for Energy Efficiency and Demand Response in Corrugated Cardboard Manufacturing Facilities  

E-print Network

Corrugated cardboard manufacturing is an energy intensive process, in both electric power and steam. Based on the US Census Bureau, there are approximately 1,733 corrugated and solid fiber box manufacturing facilities in the United States...

Chow, S.; Hackett, B.; Ganji, A. R.

2005-01-01

122

Heat Pipes  

NASA Technical Reports Server (NTRS)

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.

1990-01-01

123

Low loss propagation in corrugated rectangular waveguide at 1 mm wavelength  

Microsoft Academic Search

The expected low loss of a corrugated rectangular waveguide has been confirmed by measurements near 300 GHz on 20 feet of an X-band waveguide with corrugated broad walls. The corrugated walls were fabricated in copper by chemical etching using photolithographic techniques to define the pattern. Transmission was limited to about 80 percent due to imperfect transitions from the smooth-wall waveguide,

J. L. Doane

1987-01-01

124

Using genetic programming to determine Che` zy resistance coefficient in corrugated channels  

E-print Network

INTRODUCTION Three artificially corrugated channels have been experi- mentally studied. Laboratory tests aimUsing genetic programming to determine Che` zy resistance coefficient in corrugated channels Orazio Genetic Programming has been used to determine Che` zy resistance coefficient for full circular corrugated

Fernandez, Thomas

125

Piping Connector  

NASA Technical Reports Server (NTRS)

In Stennis Space Center's Component Test Facility, piping lines carry rocket propellants and high pressure cryogenic fuels. When the lines are chilled to a pretest temperature of 400 degrees below zero, ordinary piping connectors can leak. Under contract to Stennis, Reflange, Inc. developed the T-Con connector, which included a secondary seal that tolerates severe temperature change. Because of the limited need for the large and expensive T-Con product, Reflange also developed the less costly E-Con, a smaller more compact design with the same technical advantages as the T-Con.

1994-01-01

126

Linearly Polarized Modes of a Corrugated Metallic Waveguide  

SciTech Connect

A linearly polarized (LP(mn)) mode basis set for oversized, corrugated, metallic waveguides is derived for the special case of quarter-wavelength-depth circumferential corrugations. The relationship between the LP(mn) modes and the conventional modes (HE(mn), EH(mn), TE(0n), TM(0n)) of the corrugated guide is shown. The loss in a gap or equivalent miter bend in the waveguide is calculated for single-mode and multimode propagation on the line. In the latter case, it is shown that modes of the same symmetry interfere with one another, causing enhanced or reduced loss, depending on the relative phase of the modes. If two modes with azimuthal (m) indexes that differ by one propagate in the waveguide, the resultant centroid and the tilt angle of radiation at the guide end are shown to be related through a constant of the motion. These results describe the propagation of high-power linearly polarized radiation in overmoded corrugated waveguides.

Kowalski, E.J. [Massachusetts Institute of Technology (MIT); Tax, David [Massachusetts Institute of Technology (MIT); Bigelow, Timothy [Oak Ridge National Laboratory (ORNL); Rasmussen, David A [ORNL

2010-01-01

127

Determination of surface corrugation amplitude from classical atom scattering  

E-print Network

from classical atom scattering W. W. Hayes Physical Sciences Department, Greenville Technical College height variation of the corrugation function for scattering of atoms under classical conditions can be determined by a measurement of the maximum intensity in energy-resolved scattering spectra as a function

Manson, Joseph R.

128

The Impulse Response of Extruded Corrugated Core Aluminum Sandwich Structures  

E-print Network

#12;Abstract Stainless steel sandwich structures with honeycomb cellular cores have demonstratedThe Impulse Response of Extruded Corrugated Core Aluminum Sandwich Structures A Thesis Presented sandwich structures from a 6061-T6 aluminum alloy. The core relative density was 25% and was strongly

Wadley, Haydn

129

Spoof Surface Plasmon Polariton Modes Propagating Along Periodically Corrugated Wires  

Microsoft Academic Search

In this paper, we analyze in detail the characteristics of surface electromagnetic modes that can propagate along a periodically corrugated, perfectly conducting wire. We show how these modes, termed spoof surface plasmon polaritons, resemble surface plasmon polaritons supported by metallic wires at optical frequencies. The important point is that the dispersion relation of spoof surface plasmon polaritons is mainly controlled

A. I. Fernandez-Dominguez; L. Martin-Moreno; F. J. Garcia-Vidal; S. R. Andrews; S. A. Maier

2008-01-01

130

Fabrication of buried corrugated waveguides by wafer direct bonding  

Microsoft Academic Search

A new fabrication method of deeply buried corrugated waveguides is presented. It uses a direct bonding process and allows us to make efficient grating couplers in waveguides. The efficiency of the grating is enhanced by enclosing air in its grooves during the fabrication process. A demonstrator based on a waveguide produced by ion exchange has been fabricated and tested. Theoretical

S. Pelissier; G. Pandraud; A. Mure-Ravaud; A. V. Tishchenko; B. Biasse

2000-01-01

131

Moisture Diffusion through a Corrugated Fiberboard under Compres  

Microsoft Academic Search

This research develops a model using finite element to study the response of a panel made of a typical commercial corrugated fiberboard due to an induced moisture function at one side of the fiberboard. The model predicts how the moisture diffusion will permeate through the fiber- board's layers (medium and liners) providing information on moisture content at any given point

Adeeb A. Rahman; Thomas J. Urbanik; Mustafa Mahamid

132

Transient Nonlinear Analysis of Moisture Flow through a Corrugated Fiberboard  

Microsoft Academic Search

Collapse of fiberboard packaging boxes, in the shipping industry, due to rise in humidity conditions is common and very costly. A 3D FE nonlinear model is developed to predict the moisture flow throughout a corrugated packaging fiberboard sandwich structure. The model predicts how the moisture diffusion will permeate through the layers of a fiberboard (medium and facings). The model predicts

Adeeb A. Rahman; Thomas J. Urbanik; Mustafa Mahamid

133

Bag Pipe  

NSDL National Science Digital Library

In this activity, learners explore sound by constructing their very own bagpipe instrument. Learners use PVC pipe, a ziploc bag, rubber tubing, rubber bands, a plastic bottle, and a rubber glove to build their bagpipe. Note: a drill is required, but is not included in the cost of materials.

Workshop, Environmental S.

2011-01-01

134

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

USGS Publications Warehouse

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.

Barringer, Thomas

1996-01-01

135

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

USGS Publications Warehouse

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.

Hurley, N. M., Jr.

1996-01-01

136

Optimum design of large flood relief culverts under the A89 motorway in the Dordogne - Isle confluence plain  

NASA Astrophysics Data System (ADS)

The planned A89 motorway will go through the Dordogne - Isle confluence plain, which is regularly flooded under the effect of both river discharges and ocean tides. Hydraulic transparency of the motorway embankment was one of the prerequisites imposed by the French government. In order to optimize the cost/efficiency ratio of large culverts located under the motorway, their position and size had to be determined with great accuracy. This task has been fulfilled thanks to complementary sophisticated physical scale models and 2-D numerical models. The schematization principles adopted in the 2-D numerical model concerning bridge pier grouping were validated using the physical scale model.The finite element TELEMAC-2D code was used to draw up the optimum design of this river engineering scheme. TELEMAC-2D solves the 2-D Shallow Water equations on non-structured grids in the presence of alternately dry and wet beds. The 2-D numerical modelling based on high quality topographic data allows considerable improvements to be made in the computation of flood flows in a flat valley, as compared with traditional one-dimensional techniques. Near flood relief culverts in particular, the various physical effects contributing to the overall head loss can be distinguished: bottom roughness, medium size bed variations, strong curvature of the streamlines and vortices behind abutments.The hydraulic impact of the optimum solution has been studied under different aspects (rise of maximum flood levels, increase in maximum velocity, changes in the water flow patterns, submersion time of flooded land, modification of flood routing characteristics) for a wide range of flood hydrological events.

Sauvaget, P.; David, E.; Demmerle, D.; Lefort, P.

2000-09-01

137

Experimental studies of magnetically scannable leaky-wave antennas having a corrugated ferrite slab\\/dielectric layer structure  

Microsoft Academic Search

The radiation characteristics of a magnetically scannable leaky-wave antenna using a corrugated ferrite slab supported by a Teflon waveguide have been demonstrated experimentally. A corrugated polycrystalline yttrium iron garnet (YIG) slab having the dimensions 150.0 mm x 15.0 mm x 10 mm has been fabricated. The corrugation depth, corrugation spacing, and number of corrugations are 150.0 microns, 2.0 mm, and

Heshmatollah Maheri; Makoto Tsutsumi; Nobuaki Kumagai

1988-01-01

138

Heat pipe technology  

NASA Technical Reports Server (NTRS)

A bibliography of heat pipe technology to provide a summary of research projects conducted on heat pipes is presented. The subjects duscussed are: (1) heat pipe applications, (2) heat pipe theory, (3) design and fabrication, (4) testing and operation, (5) subject and author index, and (6) heat pipe related patents.

1972-01-01

139

Optimization of corrugated QWIPs for high-speed infrared imaging  

NASA Astrophysics Data System (ADS)

Corrugated quantum well infrared photodetectors (C-QWIPs) offer simple detector architecture for large format infrared focal plane arrays. The detector relies on inclined sidewalls to couple normal incident light into the absorbing material. In this work, we describe the light coupling characteristics of C-QWIPs based on a simple geometrical-optics model and a rigorous modal transmission-line model. Based on these two theoretical models, we optimize the detector structure toward a large quantum efficiency ?. In addition, we investigated material structures that give both high photoconductive gain and large spectral bandwidth. Combining these two material properties with a large ? offered by the corrugated structure, the detector photocurrent can be greatly increased, which will be useful in high speed infrared imaging.

Choi, Kwong-Kit; Leung, Kok Ming; Tamir, Theodor; Monroy, Carlos; Wang, F.; Tsui, Daniel C.

2004-08-01

140

Low-loss broadband multimode corrugated waveguide performance  

NASA Astrophysics Data System (ADS)

A 30-m-long waveguide run using circular corrugated waveguide (i.d.=6.35 cm) with a corrugated period and depth of 254 ?m (0.01 in.) has been fabricated and installed on TFTR (Tokamak Fusion Test Reactor) for use in electron cyclotron emission measurements, and is the first large scale application of this type of waveguide. It is designed for low-loss (<0.01 dB/m) multimode operation between 75 and 575 GHz, and includes three E-plane and four H-plane miter bends. Single-mode measurements at 140 GHz and multimode measurements at 250 GHz indicate that both ohmic losses as well as loss due to mode conversion are negligible with this type of transmission line.

Cavallo, A.; Doane, J.; Cutler, R.

1990-09-01

141

Progress Toward Corrugated Feed Horn Arrays in Silicon  

NASA Astrophysics Data System (ADS)

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.

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

2009-12-01

142

Variational analysis of dielectrically loaded multidepth corrugated waveguides  

NASA Astrophysics Data System (ADS)

Propagation behavior in a multidepth corrugated waveguide is analyzed. The analysis is based on the theory of nonstandard eigenvalues and variational methods. The method is tested for an empty dual-depth corrugated waveguide, which results have been previously calculated in the literature by using surface-impedance and space harmonic methods. These methods are summarized. Also some space harmonic formulas are rederived into the form where the fundamental surface admittance component is separated from the higher order terms. It is seen that with elementary trial functions very accurate dispersion relations can be obtained by the variational method. Encouraged by this, the method is then extended for a tri-depth guide operating in three different frequency bands, and for dielectrically loaded dual- and tri-depth guides. The latter appear encouraging because of their simpler fabrication techniques.

Oskanen, M. I.

1988-01-01

143

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

SciTech Connect

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.

Burt, G.; Ronald, K.; Young, A.R.; Phelps, A.D.R.; Cross, A.W.; Konoplev, I.V.; He, W.; Thomson, J.; Whyte, C.G. [Department of Physics, University of Strathclyde, Glasgow, G4 0NG, Scotland (United Kingdom); Samsonov, S.V.; Denisov, G.G.; Bratman, V.L. [Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod, 603950 (Russian Federation)

2004-10-01

144

Corrugated outer sheath gas-insulated transmission line  

DOEpatents

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.

Kemeny, George A. (Pittsburgh, PA); Cookson, Alan H. (Churchill Boro, PA)

1981-01-01

145

Thermally Tuning Terahertz Surface Plasmon Polaritons in Corrugated Semiconductor Films  

Microsoft Academic Search

In this work, we show that surface plasmon polaritons (SPPs) at terahertz (THz) frequencies can be tuned by changing the temperature in a periodically corrugated thin film of indium antimonide (InSb) sandwiched between air and dielectric. When a THz electromagnetic wave illuminates the structure, the temperature-dependent THz SPPs can be excited, and the first and second-order modes and their cross-couplings

Xin Wu; Ruwen Peng; De Li; Ruili Zhang; Renhao Fan; Claudio Ferrari; Mu Wang

2009-01-01

146

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

SciTech Connect

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.

Zhu, Y.T.; Jiang, H. [and others

2000-10-01

147

Transient coexisting nanophases in ultrathin films confined between corrugated walls  

SciTech Connect

Grand-canonical Monte Carlo and microcanonical molecular dynamics methods have been used to simulate an ultrathin monatomic film confined to a slit-pore [i.e., between solid surfaces (walls)]. Both walls comprise atoms rigidly fixed in the face centered cubic (100) configuration; one wall is smooth on a nanoscale and the other is corrugated (i.e., scored with regularly spaced rectilinear grooves one to several nanometers wide). Properties of the film have been computed as a function of the lateral alignment (registry), with the temperature, chemical potential, and distance between the walls kept constant. Changing the registry carries the film through a succession of equilibrium states, ranging from all solid at one extreme to all fluid at the other. Over a range of intermediate registries the film consists of fluid and solid portions in equilibrium, that is fluid-filled nanocapillaries separated by solid strips. The range of registries over which such fluid--solid equilibria exist depends upon the width of the grooves and the frequency of the corrugation. For grooves of width comparable to the range of the interatomic potential, fluid and solid phases cease to coexist. In the limit of very wide grooves the character of the film is similar to that of the film confined by strictly smooth walls. The rich phase behavior of the confined film due to the coupling between molecular (registry) and nano (corrugation) scales has obvious implications for boundary lubrication.

Curry, J.E.; Zhang, F.; Cushman, J.H. (Lilly Hall of Life Sciences, Purdue University, West Lafayette, Indiana 47907 (United States)); Schoen, M. (Institut fuer Theoretische Physik, Technische Universitaet Berlin, Hardenbergstr. 36, 10623 Berlin (Germany)); Diestler, D.J. (Department of Agronomy, Keim Hall, University of Nebraska-Lincoln, Lincoln, Nebraska 68583-0915 (United States))

1994-12-15

148

Measuring the electronic corrugation at the metal/organic interface  

NASA Astrophysics Data System (ADS)

Angle-resolved two-photon photoemission is used to probe the image potential states on monolayers of metal-free phthalocyanine (H2Pc) and cobalt phthalocyanine (CoPc) on the Ag(100) and Ag(111) surfaces. We find that in the plane of the surface the normally flat potential landscape becomes significantly corrugated in the presence of the phthalocyanine lattice, causing the opening of a band gap in the first image potential state, in agreement with previous findings. Interestingly, the data show that the absence of the electron dense metal center does not qualitatively alter this picture. Experiments conducted on Ag(100) and Ag(111) crystals demonstrate that the surface band structure and symmetry of the metal surface plays a minor role in the band folding phenomenon. A two-dimensional model that takes into account both the band structure of the substrate and the corrugation of the potential landscape in the surface plane due to the molecular lattice is presented and compared to experiment. This model enables the observation that, counter to intuition, the Co metal center at the CoPc/Ag interface actually smooths the interfacial potential relative to that of the H2Pc/Ag interface. We suggest that the strong corrugation of the potential at the organic/metal interface measured herein may account for the recent observation of surface umklapp scattering in recent ultraviolet photoemission experiments on organic/metal interfaces.

Caplins, Benjamin W.; Shearer, Alex J.; Suich, David E.; Muller, Eric A.; Harris, Charles B.

2014-04-01

149

Interaction of streamers and stationary corrugated ionization waves in semiconductors  

NASA Astrophysics Data System (ADS)

A numerical simulation of evolution of an identical interacting streamers array in semiconductors has been performed using the diffusion-drift approximation and taking into account the impact and tunnel ionization. It has been assumed that the external electric field E0 is static and uniform, the background electrons and holes are absent, the initial avalanches start simultaneously from the nodes of the plane hexagonal lattice, which is perpendicular to the external field, but the avalanches and streamers are axially symmetric within a cylinder of radius R. It has been shown that under certain conditions, the interaction between the streamers leads finally either to the formation of two types of stationary ionization waves with corrugated front or to a stationary plane ionization wave. A diagram of different steady states of this type of waves in the plane of parameter E0,R has been presented, and a qualitative explanation of the plane partition into four different regions has been given. Characteristics of corrugated waves have been studied in detail and discussed in the region of R and E0 large values, in which the maximum field strength at the front is large enough for the tunnel ionization implementation. It has been shown that corrugated waves ionize semiconductors more efficiently than flat ones, especially in relatively weak external fields.

Kyuregyan, A. S.

2014-04-01

150

Laterally-corrugated ridge-waveguide distributed feedback lasers at 980 nm  

Microsoft Academic Search

The paper presents simulation results for laterally-corrugated ridge-waveguide distributed-feedback (DFB) semiconductor lasers emitting at 980 nm, along with measured results. The effect of the corrugation on the laser output characteristics is discussed. Almost 50 dB side-mode suppression ratio was achieved for the laterally-corrugated ridge waveguide DFB lasers fabricated using nano-imprint-lithography.

A. Laakso; J. Viheriala; M. Dumitrescu; J. Tommila; K. Haring; T. Leinonen; S. Ranta; M. Pessa

2008-01-01

151

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

NASA Astrophysics Data System (ADS)

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.

Barnes, Caleb J.; Visbal, Miguel R.

2013-11-01

152

A case study of wear-type rail corrugation prediction and control using speed variation  

NASA Astrophysics Data System (ADS)

The transportation noise phenomenon known as wear-type rail corrugation is a significant problem in railway engineering, that manifests as an undesirable periodic wear pattern on the contact surface of rails. Rail corrugations induce unwanted vibrations, noise and damage to vehicle and track systems. Currently the only reliable solution to corrugation is removal by grinding at significant expense to the railway operator. Recent research by the current authors has theoretically shown that uniformity in train pass speeds over a site enhances corrugation growth rate and that broadening the probabilistic pass speed distribution may be a possible method of mitigating corrugation growth. To further test these results and to quantify the expected performance, in this paper, field measured data from a site with recurrent corrugation is used to tune and validate both efficient analytical and more complex numerical corrugation growth models. In doing so, previously developed analytical predictions for growth rate under varying speed conditions are generalised to both tangent track and cornering conditions. Validation and comparison with more complex benchmarked numerical models and field measurements is therefore achieved. The effect of changing the field measured pass speed distribution is then investigated and results quantifying the expected reduction in corrugation growth rate are presented, compared and discussed. Possible undesirable side-effects of implementing such a corrugation control strategy are also investigated.

Meehan, P. A.; Bellette, P. A.; Batten, R. D.; Daniel, W. J. T.; Horwood, R. J.

2009-08-01

153

Effect of corrugated cover directional transmittance on the thermal performance of a solar collector  

NASA Astrophysics Data System (ADS)

The benefits of light weight, structural strength, and reduced costs without significant reduction of transmission of solar energy of a corrugated fiberglass composite cover promise wide utilization of this cover in solar collectors to suppress convective and radiative heat losses from the absorber panel. In order to evaluate the thermal performance of a collector with a corrugated cover, the directional transmittance of the cover must be available. A study was undertaken to develop a model for the directional transmittance of a corrugated cover as represented by a sinusoidal periodic function. As an application of this model, hourly and daily thermal efficiencies of a solar collector with a corrugated cover are presented.

Smith, T. F.; Chaidar, S.

1981-05-01

154

Flood magnitude and frequency of Franklin Pond tributary at the culvert on New Jersey Route 23, Franklin Borough, Sussex County, New Jersey  

USGS Publications Warehouse

Flood magnitude and frequency values are presented for Franklin Pond tributary at the culvert at milepost 32.2 of New Jersey Route 23, Franklin Borough, New Jersey. The values were determined by using the New Jersey Department of Environmental Protection Special Report 38 method. A description of the drainage-basin characteristics also is included in this report. The 100-year-flood estimate is 218 cubic feet per second.

Barringer, Thomas

1996-01-01

155

Flood magnitude and frequency of Black Creek at the culvert on New Jersey Route 94, Vernon Township, Sussex County, New Jersey  

USGS Publications Warehouse

The magnitude and frequency of floods at Black Creek tributary at the culvert on New Jersey Route 94 at milepost 43.0 in Vernon Township, New Jersey, were determined by using the New Jersey Department of Environmental Protection Special Report 38 method. Estimates of flood magnitude and frequency calculated by the Special Report 38 method, as well as drainage-basin characteristics, are included in this report. The 100-year-flood estimate is 261 cubic feet per second.

Barringer, T.H.

1996-01-01

156

Flood magnitude and frequency of Little Timber Creek at the culvert on Interstate Route 295, Haddon Heights Township, Camden County, New Jersey  

USGS Publications Warehouse

The magnitude and frequency of floods at the Little Timber Creek at the culvert on Interstate 295, at milepost 28.9, in Haddon Heights 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 estimate is 770 cubic feet per second.

Barringer, T.H.

1996-01-01

157

Plasma Heating by an Electron Beam in Corrugated Magnetic Field  

Microsoft Academic Search

New experimental results from the multimirror trap GOL-3 are presented. Deuterium plasma of $~10^21 m^-3$ density is heated by a high power relativistic electron beam (peak parameters are ~1 MeV, ~25 kA, ~8 $\\\\mu$s, ~120 kJ). Magnetic system of the facility is a 12-meter-long axisymmetrical solenoid with corrugated magnetic field, which consists of 55 cells with $B_max\\/B_min$=4.8\\/3.2 T. Collective plasma

V. V. Postupaev; A. V. Arzhannikov; V. T. Astrelin; A. M. Averkov; A. D. Beklemishev; A. V. Burdakov; I. A. Ivanov; M. V. Ivantsivsky; V. S. Koidan; K. I. Mekler; S. V. Polosatkin; A. F. Rovenskikh; S. L. Sinitsky; Yu. S. Sulyaev; E. R. Zubairov

2004-01-01

158

On the isothermal geometry of corrugated graphene sheets  

E-print Network

Variational geometries describing corrugated graphene sheets are proposed. The isothermal thermomechanical properties of these sheets are described by a 2-dimensional Weyl space. The equation that couples the Weyl geometry with isothermal distributions of the temperature of graphene sheets, is formulated. This material space is observed in a 3-dimensional orthogonal configurational point space as regular surfaces which are endowed with a thermal state vector field fulfilling the isothermal thermal state equation. It enables to introduce a non-topological dimensionless thermal shape parameter of non-developable graphene sheets. The properties of the congruence of lines generated by the thermal state vector field are discussed.

Andrzej Trzesowski

2013-12-17

159

RESEARCH ARTICLE An experimental study of a bio-inspired corrugated airfoil  

E-print Network

RESEARCH ARTICLE An experimental study of a bio-inspired corrugated airfoil for micro air vehicle was conducted to investigate the aerodynamic characteristics of a bio- inspired corrugated airfoil compared with a smooth-sur- faced airfoil and a flat plate at the chord Reynolds number of ReC = 58

Hu, Hui

160

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

NASA Technical Reports Server (NTRS)

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.

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

1968-01-01

161

The compressive and shear responses of corrugated and diamond lattice materials  

E-print Network

Abstract Corrugated and diamond lattice materials have been manufactured as the cores of sandwich panels corrugated and diamond cores are weaker than the pyramidal and square-honeycomb under compression; Plastic buckling; Energy-absorption; Sandwich panels 1. Introduction Micro-architectured materials

Fleck, Norman A.

162

Three-dimensional train track model for study of rail corrugation  

NASA Astrophysics Data System (ADS)

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.

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

2006-06-01

163

Analysis of cylindrical waveguide with corrugation and synthesis of radiated beams pattern  

Microsoft Academic Search

The dielectric waveguide with corrugation has been of considerable interest in the optical or millimeter wave regions, because of its applications such as filters, couplers and leaky wave antennas. In the frequency region where the spatial harmonics become leaky, the wave energy is leaked in several different directions. Conventional corrugations consist of a fundamental and harmonic wave forms with respect

H. Kubo

1995-01-01

164

Corrugated substrate integrated waveguide with dual band non-Bragg resonance  

Microsoft Academic Search

A corrugated substrate integrated waveguide (SIW) with dual non-Bragg resonance frequencies at 4.8 GHz and 8 GHz is presented, where the two sidewalls of the SIW are not straight but corrugated in sinusoidal shape. Theory has been described and backed up by numerical simulation. In addition, test devices are fabricated and characterized. The measurement results show good agreement with those

Xiaoyu Cheng; Jungkwun Kim; Cheolbok Kim; PitFee Jao; David E. Senior; Yong-Kyu Yoon

2011-01-01

165

ADHESIVE IN THE BUCKLING FAILURE OF CORRUGATED FIBERBOARD: A FINITE ELEMENT INVESTIGATION  

Microsoft Academic Search

This research study proposed to include the glue material in a finite element model that represents the actual geometry and material properties of a corrugated fiberboard. The model is a detailed representation of the different components of the structure (adhesive, linerboard, medium) to perform buckling analysis of corrugated structures under compressive loads. The objective of this analysis was to quantify

Adeeb A. Rahman; Said Abubakr

166

Effect of Relative Humidity on the Optimum Flute Shape for Corrugated Fiberboard  

Microsoft Academic Search

Container stacking strength is an important performance requirement of corrugated fiberboard. The objective of this study is to examine theoretically how fluting geometry affects fiberboard strength and stiffness under standard relative humidity (RH) and high RH conditions. The fluted medium in a corrugated fiberboard is modeled as a connection of curved arc and straight flank segments passing through the middle

Thomas J. Urbanik

167

Directional terahertz emission from corrugated InAs structures.  

PubMed

The terahertz (THz) radiation from transient dipoles, formed by distinct diffusion coefficients between oppositely charged carriers as often observed in low band gap semiconductors, propagates with an anisotropic amplitude distribution perpendicular to the dipole axis along the diffusive motion. By directionally adjusting the electronic diffusion, we conceptualize groove-patterned THz emitters based on (100) InAs thin films and demonstrate the unidirectional radiation. Line-of-sight emission along the surface-normal direction is greatly enhanced in a distributed asymmetric trapezoid with its period similar to the electronic diffusion length of InAs. This directional enhancement is in clear contrast to the constant emission amplitude along the lateral direction, regardless of pattern scale, which manifests the role of groove patterns as microscale reflectors in laterally corrugating the carrier density. In contrast to the rather limited nonlinearity in (100) plane, the azimuthal angle dependence of the THz field amplitude in corrugated samples shows a combined effect of diffusive transport and second-order nonlinearity, whose compositional contributions varies in different structures. PMID:24105518

Yim, Jong-Hyuk; Jeong, Hoonil; Irfan, Muhammad; Lee, Eun-Hye; Song, Jin-Dong; Jho, Young-Dahl

2013-08-26

168

Imaging Local Electronic Corrugations and Doped Regions in Graphene  

SciTech Connect

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.

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

2011-12-31

169

Corrugated fiberboard as a positioning insert for patients undergoing radiotherapy.  

PubMed

We have developed a new body fixation system for single patient use, which consists of a vacuum cushion, a thermoplastic fixation sheet which is used to suppress involuntary and voluntary patient movement, and a triple-wall corrugated fiberboard base plate to which both the vacuum cushion and the thermoplastic sheet are affixed. To evaluate the characteristics of the fiberboard as a patient-positioning insert, the photon beam attenuation of a fiberboard base plate, a carbon-fiber base plate, and a vacuum-formed cushion were compared. The strength of the fiberboard was also evaluated. The attenuation for the carbon-fiber base plate was 3.7% and 2.6% in 4 MV and 10 MV photon beams, respectively, while the results were less for the fiberboard base plate, i.e. 1.9% and 1.6%. The vacuum-formed cushion had a minimal effect on transmission. None of the materials subsided under the weight loading of 20 g/cm(2). There was no difference between the thicknesses of the fiberboard before and after a 50 times daily load with the 60 kg weight of a volunteer. Corrugated fiberboard is a robust and low attenuating material that functions well as a patient-positioning insert. PMID:19755802

Nakamura, Katsumasa; Yoshikawa, Haruo; Akai, Tomoharu; Nomoto, Satoshi; Shioyama, Yoshiyuki; Kuwabara, Yasuo; Yoshimitsu, Kengo

2010-01-01

170

Interfacial flows in corrugated microchannels: flow regimes, transitions and hysteresis  

E-print Network

configuration. Some of the regimes are new, while others have been observed before in straight tubes and pipes. For one, gravity and inertia are often negligible since the Bond number and Reynolds number are much below

Feng, James J.

171

Insulated pipe clamp design  

SciTech Connect

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.

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

1980-01-01

172

A Large L-Band Rectangular Corrugated Horn  

SciTech Connect

This paper describes a lightweight, corrugated-horn antenna, constructed from sheet metal. Over a 1.3-1.7 GHz operating band, its half-power beam width is approximately 20{sup o} in the E-plane and varies from 17{sup o} to 13{sup o} in the H-plane. Quarter-wave choke slots at the aperture help to reduce the E-plane sidelobes below -55 dB at angles greater than 90{sup o}, while the H-plane sidelobes lie in that range both with and without choke slots. Return loss throughout the operating band is -25 dB or below. Critical dimensions are provided, together with useful guidelines for designing similar antennas.

Witebsky, C.; Smoot, G.F.; Levin, S.; Bensadoun, M.

1987-01-01

173

Mechanics, slip behavior, and seismic potential of corrugated dip-slip faults  

NASA Astrophysics Data System (ADS)

To better understand the mechanics and seismic potential of nonplanar fault surfaces, we present results from a suite of numerical models of faults with sinusoidal corrugations in the downdip direction. Systematic variations in corrugation wavelength, amplitude, and loading angle are introduced to determine the effects on slip behavior and seismic moment release. We find that corrugated faults, in general, slip less than planar faults. Changes in slip behavior are nearly scale-independent and are dominantly controlled by the amplitude/wavelength of corrugations. Model results suggest that obliquely loaded corrugated faults accumulate less strike slip than a planar fault with the same tip line dimensions and average orientation. This result implies that slip direction is not a reliable indicator of regional stress direction and may at least partially explain repeated, nearly pure dip-slip coseismic events at oblique plate boundaries. Though the scalar seismic moment release is always less for corrugated fault surfaces due to a greater reduction in slip compared to increased surface area, for geologically reasonable corrugation geometries, changes in total scalar moment release are not significantly different than planar faults. Techniques that utilize highly simplified fault geometries may therefore accurately reproduce scalar moment release but will nonetheless incorrectly predict coseismic slip magnitudes and distributions, as well as regional stress orientations.

Marshall, Scott T.; Morris, Anna C.

2012-03-01

174

Scaling of premixed turbulent flames in the corrugated regime  

SciTech Connect

A novel apparatus for studying premixed combustion, involving the flow through a wide-angled diffuser, is described. Flames in pure methane/air mixtures and in methane/hydrogen/air have been stabilised at various heights in the diffuser, with various types of turbulence generators at inlet. The stabilisation conditions thus embraced a range of turbulence levels and integral length scales in the corrugated flamelet regime. Particle image velocimetry and planar laser-induced fluorescence were deployed to obtain the instantaneous velocity field in the unburnt mixture and the location of the flame front. Ensemble averages over 200 images allowed the statistics for 2-D flamelet surface density and the thickness of the flame brush to be measured in flames that were nearly planar in the mean. The flamelet surface density S was shown to be related to the length scale and the turbulence level, albeit in a nonlinear manner. However, there was no clear correlation for the flame brush thickness {delta}{sub T}, two different perforated plates generating turbulence at the same level and of the same length scale but giving very different thicknesses. Integrating S across the flame and combining with information from elsewhere on the effect of stretch on the laminar burning velocity, the consumption speed was estimated. As in all determinations of this parameter in the literature, this was found to be very much less than the turbulent displacement speed. Residual mean flame curvature is not thought to be sufficient to account for this, and explanations are being sought in a more complex response of the flamelets to the turbulence than just pure corrugation. (author)

Lawn, C.J. [Department of Engineering, Queen Mary, University of London, Mile End Road, London, E1 4NS (United Kingdom); Schefer, R.W. [Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94551-0969 (United States)

2006-07-15

175

Pipe-to-pipe impact program  

SciTech Connect

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.

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

1984-06-01

176

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

NASA Astrophysics Data System (ADS)

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.

Hord, Kyle

177

Heat pipes. [technology utilization  

NASA Technical Reports Server (NTRS)

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.

1975-01-01

178

Antigravity heat pipe  

Microsoft Academic Search

The general design and principle of operation of an antigravity heat pipe, in which the heat transfer agent is supplied to the evaporator against the force of gravity, are descussed. Analytical expressions describing the operation of the heat pipe are presented, as are experimental results obtained for an acetone-charged antigravity heat pipe.

N. I. Kliuev

1989-01-01

179

Previewing Semantic Web Pipes  

Microsoft Academic Search

In this demo we present a first implementation of Semantic Web Pipes, a powerful tool to build RDF-based mashups. Semantic Web pipes are defined in XML and when executed they fetch RDF graphs on the Web, operate on them, and produce an RDF output which is itself accessible via a stable URL. Humans can also use pipes directly thanks to

Christian Morbidoni; Danh Le Phuoc; Axel Polleres; Matthias Samwald; Giovanni Tummarello

2008-01-01

180

A corrugated perfect magnetic conductor surface supporting spoof surface magnon polaritons.  

PubMed

In this paper, we demonstrate that spoof surface magnon polaritons (SSMPs) can propagate along a corrugated perfect magnetic conductor (PMC) surface. From duality theorem, the existence of surface electromagnetic modes on corrugated PMC surfaces are manifest to be transverse electric (TE) mode compared with the transverse magnetic (TM) mode of spoof surface plasmon plaritons (SSPPs) excited on corrugated perfect electric conductor surfaces. Theoretical deduction through modal expansion method and simulation results clearly verify that SSMPs share the same dispersion relationship with the SSPPs. It is worth noting that this metamaterial will have more similar properties and potential applications as the SSPPs in large number of areas. PMID:24921768

Liu, Liang-liang; Li, Zhuo; Gu, Chang-qing; Ning, Ping-ping; Xu, Bing-zheng; Niu, Zhen-yi; Zhao, Yong-jiu

2014-05-01

181

Gyrokinetic simulations of off-axis minimum-q profile corrugations  

SciTech Connect

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.

Waltz, R.E.; Austin, M.E.; Burrell, K.H.; Candy, J. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States)

2006-05-15

182

Pipe Line Control  

NASA Technical Reports Server (NTRS)

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.

1978-01-01

183

Overall Thermal Performance of Flexible Piping Under Simulated Bending Conditions  

NASA Technical Reports Server (NTRS)

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.

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

2001-01-01

184

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

185

Low loss propagation in corrugated rectangular waveguide at 1 mm wavelength  

NASA Astrophysics Data System (ADS)

The expected low loss of a corrugated rectangular waveguide has been confirmed by measurements near 300 GHz on 20 feet of an X-band waveguide with corrugated broad walls. The corrugated walls were fabricated in copper by chemical etching using photolithographic techniques to define the pattern. Transmission was limited to about 80 percent due to imperfect transitions from the smooth-wall waveguide, but the incremental loss was less than 2 percent in each 5-foot section. The loss in an E-plane miter bend was too small to measure, while the approximately 3 percent loss in an H-plane miter bend probably corresponds to the difficulty in continuing the broad-wall corrugations all the way to the smooth mirror (miter).

Doane, J. L.

1987-01-01

186

Thermal Energy Storage Using Phase Change Materials in Corrugated Copper Panels  

E-print Network

transfer fluid (HTF) for different enhancement techniques. The goal of this study is to experimentally investigate the effectiveness of corrugated PCM panels with high surface-to-volume ratio in forced convection as a function of HTF mass flow rate...

Aigbotsua, Clifford Okhumeode

2012-07-16

187

A Ruthenium-Based Multimetal-Contact RF MEMS Switch With a Corrugated Diaphragm  

Microsoft Academic Search

This paper presents a ruthenium metal-contact RF microelectromechanical system switch based on a corrugated silicon oxide\\/silicon nitride diaphragm. The corrugations are designed to substantially reduce the influence of the fabrication-induced stress in the membrane, resulting in a highly insensitive design to process parameter variations. Furthermore, a novel multilayer metal-contact concept, comprising a 50-nm chromium\\/50-nm ruthenium\\/500-nm gold\\/50-nm ruthenium structure, is introduced

Feixiang Ke; Jianmin Miao; Joachim Oberhammer

2008-01-01

188

Novel thick-grating beam-squeezing device in Ta2O5 corrugated planar waveguide  

NASA Astrophysics Data System (ADS)

The fabrication and performance of a novel thick-grating beam-squeezing device in a Ta2O5 corrugated planar waveguide is described. The device, in which the design relies on consideration of the group velocities of the light inside the periodic guide at Bragg incidence, features a curved (hyperbolic) boundary transition between smooth and corrugated waveguide regions. A contraction ratio of about 30 is achieved.

Russell, P. St. J.

1984-01-01

189

A wide-band corrugated rectangular waveguide phase shifter for cryogenically cooled receivers  

Microsoft Academic Search

A wide-band phase shifter rectangular in cross section with transverse corrugations on all four walls is presented. The loading for the two orthogonal modes is different and is achieved by choosing dissimilar corrugation parameters. This phase shifter measures a return loss of -25 dB or better and differential phase shift of 903.3 between 18.9-26.5 GHz, This all-metal robust phase shifter

S. Srikanth

1997-01-01

190

Realization of Long-Period Corrugated Grating in Silica-on-Silicon-Based Channel Waveguide  

Microsoft Academic Search

Long-period corrugated grating in silica-on-silicon-based channel waveguide is realized by making periodic corrugation on top of a relatively high-indexed (contrast ap.8%) Ge-doped silica waveguide, which is sandwiched between undoped silica undercladding and boro-phospho-silicate-glass overcladding layers. Resonance wavelength of the 15-mm-long grating is found at ~1581 nm, having negligible polarization dependency at room temperature, with a grating strength of ~11 dB

Suchandan Pal; Ashok Chauhan; Mahendra Singh; Pawan Kumar; Mukesh Sharma; Nirmal Pradhan; Kuldip Singh; C. Dhanavantri

2009-01-01

191

Automated design of corrugated conical horns for dual-band applications  

Microsoft Academic Search

A highly efficient full-wave model and CAD of conical corrugated horns is discussed. The capabilities of the CAD tools are demonstrated by the design of dual-hand horn operating over the 20 - 21.5 and 29.5 - 31.5 GHz bands. A comparison of the designed horn characteristics obtained with the Kirchhoff-Hnygens approach and Wiener-Hopf technique is presented. Dual-band corrugated conical horns

A. Perov; L. Rud; S. Senkevich; V. Tkachenko

2004-01-01

192

Novel thick-grating beam-squeezing device in Ta2O5 corrugated planar waveguide  

Microsoft Academic Search

The fabrication and performance of a novel thick-grating beam-squeezing device in a Ta2O5 corrugated planar waveguide is described. The device, in which the design relies on consideration of the group velocities of the light inside the periodic guide at Bragg incidence, features a curved (hyperbolic) boundary transition between smooth and corrugated waveguide regions. A contraction ratio of about 30 is

P. St. J. Russell

1984-01-01

193

A corrugated bridge of low residual stress for RF-MEMS switch  

Microsoft Academic Search

This paper presents the theory, design, fabrication and characterization of the corrugated membrane for a low-actuation voltage RF-MEMS switch for microwave and millimeter-wave applications. Analytical analyses and experimental results have been carried out to derive algebraic expressions for the mechanical actuation mechanics of corrugated membrane for a low residual stress. It is shown that the residual stress of both types

Yo-Tak Song; Hai-Young Lee; Masayoshi Esashi

2007-01-01

194

Sequence identification of Mogollon-Mimbres corrugated wares from the NAN Ruin, Grant County, New Mexico  

E-print Network

SEQUENCE IDENTIFICATION OF MOGOLLON-MIMBRES CORRUGATED WARES FROM THE NAN RUIN, GRANT COUNTY, NEW MEXICO A Thesis by TERESA ANN MCCOLLUM Subinitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF ARTS December 1992 Major subject; . Anthropology SEQUENCE INDENTIFICATION OF MOGOLLON-MIMBRES CORRUGATED WARES FROM THE NAN RUIN, GRANT COUNTY, NEW MEXICO A Thesis by TERESA ANN MCCOLLUM Approved as to style...

McCollum, Teresa Ann

2012-06-07

195

An experimental investigation of beam shear webs utilizing corrugations for stiffeners  

E-print Network

AN EXPERIMENTAL INVESTIGATION OF BEAM SHEAR WEBB UTILIZING CORRUGATIONS FOR STIFFENERS A Thesis By JOSEPH HEBERT& JR, Submitted to the Graduate School of the Agricultural and Mechanical College of Texas In Partial Fulfillment... of the Requirements for the Degree of MASTER OF SCIENCE August, 1959 Department of Aeronautical Engineering Major Subject: Aeronautical Engineering AN EXPERIMENTAL INVESTIGATION OF BEAM SHEAR WEBS UTILIZING CORRUGATIONS FOR STIFFENERS A Thesis JOSEPH HEBERT...

Hebert, Joseph

2012-06-07

196

Propagation of Lamb waves in one-dimensional radial phononic crystal plates with periodic corrugations  

NASA Astrophysics Data System (ADS)

In this paper, we theoretically investigate the propagation characteristics of Lamb waves in one-dimensional radial phononic crystal plates with periodic corrugations. The dispersion relations, the power transmission spectra, and the displacement fields of the eigenmodes are calculated by using the finite element method based on two-dimensional axial symmetry models in cylindrical coordinates. The axial symmetry model is validated by three-dimensional finite element model in rectangular coordinates. The effects of the geometrical parameters on the band gaps are further explored numerically. Numerical results show that several complete band gaps with a variable bandwidth exist for Lamb waves in the proposed structures. The formation mechanism of opening the acoustic band gaps is attributed to the coupling between the Lamb modes and the corrugation mode. The band gaps are significantly dependent upon the geometrical parameters such as the corrugation height, the corrugation width, and the plate thickness. Significantly, as the increase of corrugation height, band width shifts, new band gaps appear, the bands become flat, and the corrugation mode plays a more prominent role in the opening of Lamb wave band gaps. These properties of Lamb waves in the radial phononic crystal plates can potentially be applied to optimize band gaps, generate filters, and design acoustic devices.

Li, Yinggang; Chen, Tianning; Wang, Xiaopeng; Yu, Kunpeng; Chen, Weihua

2014-02-01

197

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

198

Measurement of washboarding of corrugated cardboard using digital image profilometry  

NASA Astrophysics Data System (ADS)

A prototype digital image profilometer has been constructed to measure washboarding of corrugated cardboard. The profilometer consists of a diode laser, collimating optics, a grating and CCD camera. The laser beam is projected through the grating to produce straight bars that illuminate the sample at 90 degrees to the undulations. The deformation of the bars projected onto the sample, tilted at 75 degrees to the camera, is analyzed using Fourier analysis to produce a surface profile of the sample. A series of 1-D Fourier transforms are calculated from the intensity profile for successive scan lines at right angles to the bars projected onto the surface. The average depth profile for each scan line is then derived, after phase unwrapping, from the phase of the dominant frequency of the spatial frequency spectrum. The profilometer can reliably measure washboarding to a depth resolution of less than 10 microns over an area of 20 cm by 20 cm in less than 4 seconds on a 486DX2/66 computer.

Reich, Michael H.; Allan, Russell

1996-02-01

199

Corrugated Quantum Well Infrared Photodetector Focal Plane Array Test Results  

NASA Technical Reports Server (NTRS)

The corrugated quantum-well infrared photodetector (C-QWIP) uses total internal reflection to couple normal incident light into the optically active quantum wells. The coupling efficiency has been shown to be relatively independent of the pixel size and wavelength thus making the C-QWIP a candidate for detectors over the entire infrared spectrum. The broadband coupling efficiency of the C-QWIP makes it an ideal candidate for multiwavelength detectors. We fabricated and tested C-QWIP focal plane arrays (FPAs) with cutoff wavelengths of 11.2 and 16.2 micrometers. Each FPA has 256 x 256 pixels that are bump-bonded to a direct injection readout circuit. Both FPAs provided infrared imagery with good aesthetic attributes. For the 11.2-micrometers FPA, background-limited performance (BLIP) was observed at 60 K with f/3 optics. For the 16.2-micrometers FPA, BLIP was observed at 38 K. Besides the reduction of dark current in C-QWIP structures, the measured internal quantum efficiency (eta) remains to be high. The values for responsivity and quantum efficiency obtained from the FPA results agree well with those measured for single devices.

Goldberg, A.; Choi, K. K.; Das, N. C.; La, A.; Jhabvala, M.

1999-01-01

200

Spreading of droplet with insoluble surfactant on corrugated topography  

NASA Astrophysics Data System (ADS)

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.

Li, Chunxi; Pei, Jianjun; Ye, Xuemin

2014-09-01

201

Spatial frequency tuning for 3-D corrugations from motion parallax.  

PubMed

We provide evidence for the existence of multiple channels tuned to the spatial frequency of depth modulations defined by motion parallax. By linking the distortion of a random dot pattern to the horizontal position of an observer's head horizontally oriented 3-D corrugations were simulated in which the depth function consisted of a range of frequencies. In a baseline experiment thresholds were obtained for detecting depth modulations of single sinewaves for a range of spatial frequencies. In a masking experiment threshold signal strength was determined for detecting a signal frequency in the presence of noise with frequencies restricted to two bands around the signal component ('notched noise'). Threshold elevation was found to decrease with an increase in the spectral difference between signal and noise. By determining thresholds at various noise levels it was further established that the channel responded linearly in the tested range. Estimates of the bandwidth for spatial frequencies of 0.33 and 0.87 cycles/deg were both found to be 1.4 octaves. The results show that motion parallax processing is mediated by a series of narrowly tuned channels with bandwidths similar to those found for processing depth modulations defined by binocular disparity. PMID:10878276

Hogervorst, M A; Bradshaw, M F; Eagle, R A

2000-01-01

202

Piping inspection instrument carriage  

SciTech Connect

This invention is comprised of a pipe inspection instrument carriage for use with a pipe crawler or other locomotion means for performing internal inspections of piping surfaces. The carriage has a front leg assembly, a rear leg assembly and a central support connecting the two assemblies and for mounting an instrument arm having inspection instruments. The instrument arm has means mounted distally thereon for axially aligning the inspection instrumentation and means for extending the inspection instruments radially outward to operably position the inspection instruments on the piping interior. Also, the carriage has means for rotating the central support and the front leg assembly with respect to the rear leg assembly so that the inspection instruments azimuthally scan the piping interior. The instrument carriage allows performance of all piping inspection operations with a minimum of moving parts, thus decreasing the likelihood of performance failure.

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

1993-09-20

203

Miniature Heat Pipes  

NASA Technical Reports Server (NTRS)

Small Business Innovation Research contracts from Goddard Space Flight Center to Thermacore Inc. have fostered the company work on devices tagged "heat pipes" for space application. To control the extreme temperature ranges in space, heat pipes are important to spacecraft. The problem was to maintain an 8-watt central processing unit (CPU) at less than 90 C in a notebook computer using no power, with very little space available and without using forced convection. Thermacore's answer was in the design of a powder metal wick that transfers CPU heat from a tightly confined spot to an area near available air flow. The heat pipe technology permits a notebook computer to be operated in any position without loss of performance. Miniature heat pipe technology has successfully been applied, such as in Pentium Processor notebook computers. The company expects its heat pipes to accommodate desktop computers as well. Cellular phones, camcorders, and other hand-held electronics are forsible applications for heat pipes.

1997-01-01

204

Deployable Heat Pipe Radiator  

NASA Technical Reports Server (NTRS)

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.

Edelstein, F.

1975-01-01

205

Hydrogen Piping Experience in Chevron  

E-print Network

piping specifications and practices for hydrogen service (Cont'd) Seamless pipe (SA 106GrB or lessHydrogen Piping Experience in Chevron Refining Ned Niccolls Materials Engineer Chevron Energy perspectives from long term use of hydrogen piping in refining. Piping specifications and practices. The (few

206

Abrasion resistant heat pipe  

DOEpatents

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.

Ernst, Donald M. (Leola, PA)

1984-10-23

207

Heat Pipe Materials Compatibility  

NASA Technical Reports Server (NTRS)

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.

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

1976-01-01

208

Fatigue of web-flange weld of corrugated web girders: 1. Influence of web corrugation geometry and flange geometry on web-flange weld toe stresses  

Microsoft Academic Search

The fatigue performance of the web-flange weld of steel girders with trapezoidal corrugated webs was examined experimentally, using large-scale girder specimens, and analytically. The focus was on a region of constant bending moment. Fatigue cracks initiated at many points along the inclined folds, and then propagated perpendicular to the principal stress direction. Propagation of cracks initiating near the end of

Kengo Anami; Richard Sause; Hassan H. Abbas

2005-01-01

209

Optomechanic interaction in a corrugated phoxonic nanobeam cavity  

NASA Astrophysics Data System (ADS)

The interaction between phonons and photons is investigated theoretically in a phoxonic cavity inside a corrugated nanobeam waveguide presenting band gaps for both electromagnetic and elastic waves. The structure is made by drilling periodic holes on a silicon nanobeam with lateral periodic stubs and the tapered cavity is constructed by changing gradually the geometrical parameters of both the holes and stubs. We show that this kind of cavity displays localized phonons and photons inside the gaps, which can enhance their interaction and also promotes the presence of many optical confined modes with high quality factor. Using the finite-element method, we demonstrate that with appropriate design of the tapering construction, one can control the cavity modes frequency without altering significantly the quality factor of the photonic modes. By changing the tapering rates over the lattice constants, we establish the possibility of shifting the phononic cavity modes frequency to place them inside the desired gap, which enhances their confinement and increases the mechanical quality factor while keeping the strength of the optomechanic coupling high. In our calculations, we take account of both mechanisms that contribute to the acousto-optic interaction, namely photoelastic and interface motion effects. We show that in our case, these two effects can contribute additively to give high coupling strength between phononic and photonic cavity modes. The calculations of the coupling coefficient which gives the phonon-photon coupling strength give values as high as 2 MHz while photonic cavity modes display quality factor of 105 and even values up to 3.4 MHz but with smaller photonic quality factors.

Oudich, Mourad; El-Jallal, Said; Pennec, Yan; Djafari-Rouhani, Bahram; Gomis-Bresco, Jordi; Navarro-Urrios, Daniel; Sotomayor Torres, Clivia M.; Martnez, Alejandro; Makhoute, Abdelkader

2014-06-01

210

Extendable pipe crawler  

DOEpatents

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.

Hapstack, M.

1991-05-28

211

On the shape of a hydrostatic meniscus attached to a corrugated plate or wavy cylinder.  

PubMed

The shape of a hydrostatic meniscus attached at a fixed contact angle to a vertical plate or circular cylinder with periodic corrugations is studied by analytical and numerical methods, and the effect of wall irregularities on the shape of the contact line and vertical component of the capillary force is discussed. An asymptotic analysis for a plate with small-amplitude sinusoidal corrugations is carried out to first order with respect to the corrugation amplitude, and a boundary-value problem is formulated and solved by a shooting method to determine the meniscus shape and elevation of the contact line. The meniscus attached to a corrugated plate with rounded corners produced by a Schwarz-Christoffel mapping function for a triangular wave is considered by numerical methods. The Laplace-Young equation determining the meniscus shape is solved in orthogonal curvilinear coordinates generated by conformal mapping using a finite-difference method. The numerical results are successfully compared with the predictions of the perturbation expansion for small amplitudes and discussed with reference to the rise of a meniscus inside a dihedral angle for large amplitudes. A companion asymptotic analysis is presented for a meniscus outside a vertical circular cylinder with small-amplitude sinusoidal corrugations. The analytical predictions are successfully compared with numerical solutions of the Laplace-Young equation for a meniscus outside an elliptical cylinder with aspect ratio near unity, regarded as a deformed circle. PMID:21315363

Hill, A I; Pozrikidis, C

2011-04-15

212

An experimental study of a bio-inspired corrugated airfoil for micro air vehicle applications  

NASA Astrophysics Data System (ADS)

An experimental study was conducted to investigate the aerodynamic characteristics of a bio-inspired corrugated airfoil compared with a smooth-surfaced airfoil and a flat plate at the chord Reynolds number of Re C = 58,000-125,000 to explore the potential applications of such bio-inspired corrugated airfoils for micro air vehicle designs. In addition to measuring the aerodynamic lift and drag forces acting on the tested airfoils, a digital particle image velocimetry system was used to conduct detailed flowfield measurements to quantify the transient behavior of vortex and turbulent flow structures around the airfoils. The measurement result revealed clearly that the corrugated airfoil has better performance over the smooth-surfaced airfoil and the flat plate in providing higher lift and preventing large-scale flow separation and airfoil stall at low Reynolds numbers (Re C < 100,000). While aerodynamic performance of the smooth-surfaced airfoil and the flat plate would vary considerably with the changing of the chord Reynolds numbers, the aerodynamic performance of the corrugated airfoil was found to be almost insensitive to the Reynolds numbers. The detailed flow field measurements were correlated with the aerodynamic force measurement data to elucidate underlying physics to improve our understanding about how and why the corrugation feature found in dragonfly wings holds aerodynamic advantages for low Reynolds number flight applications.

Murphy, Jeffery T.; Hu, Hui

2010-08-01

213

Diffraction of homogeneous and inhomogeneous plane waves on a doubly corrugated liquid/solid interface.  

PubMed

This paper extends the theory of the diffraction of sound on 1D corrugated surfaces to 2D corrugated surfaces. Such surfaces, that are egg crate shaped, diffract incoming sound into all polar directions, which is fundamentally different from 1D corrugated surfaces. A theoretical justification is given for extending the classical grating equation to the case of incident inhomogeneous waves, for 1D corrugated surfaces as well as for 2D corrugated surfaces. Even though the present paper presents a theory which is valid for all angles of incidence, special attention is given to the particular case of the stimulation of surface waves by normal incident sound. The most interesting conclusion is that, depending on the frequency and the incident inhomogeneity, Scholte-Stoneley waves and leaky Rayleigh waves can be generated in different directions. This effect might be of particular interest in the development of surface acoustic wave devices and the basic idea of this steering effect can be of importance for planar actuators. PMID:15913694

Declercq, Nico F; Degrieck, Joris; Briers, Rudy; Leroy, Oswald

2005-08-01

214

Melting of electrons on corrugated surfaces: structural and dynamical properties in liquid and solid phases  

SciTech Connect

Properties of a classical system of electrons on smooth and periodically corrugated surfaces are investigated using the molecular dynamics method. In the liquid phase, the electron-electron interaction, the total internal energy, the diffusivities parallel and perpendicular to the corrugation are all periodic functions of the wavevector of the corrugation. Thermodynamic and dynamical properties reveal a first-order melting transition for electrons on a smooth surface. Study of the melting transition on the commensurate corrugated surface of wavevector lambda = ..sqrt..3/2 a (system S/sub 2/) shows a tricritical point separating a line of first-order transitions from a line of continuous transitions. On the commensurate corrugation of wavelength lambda = ..sqrt..3/4 a (system S/sub 4/) melting transition is always first order. Topological analysis of particle coordinations shows bound dislocation pairs in the electron solid, a large number of defects and grain-boundary loops to be responsible for a first-order transition, and a small density of free dislocations to be the cause of continuous melting transition. 14 references.

Vashishta, P.; Kalia, R.K.; Quinn, J.J.

1983-11-01

215

Near-Field beam measurements of corrugated horns for ALMA band 10  

NASA Astrophysics Data System (ADS)

For the receivers of the Atacama Large Millimeter and Submillimeter Array (ALMA), one of the requirements to achieve high sensitivity is to use good optics. Corrugated horns are widely used in the optics for highly sensitive receivers because of their good performance of high efficiency, low cross polarization, and so on. As well as those receivers, we consider to use a corrugated horn for the ALMA band 10 (787-950 GHz) receiver. To characterize the performance of fabricated horns experimentally, we developed a phase and amplitude antenna test system. The signal source consists of a W-band Gunn oscillator followed by a nonupler with an open waveguide probe on an X-Y-Z-? translation stage. A corrugated horn is attached to a subharmonic Schottky diode mixer pumped by another W-band Gunn oscillator. Both Gunn oscillators are phase-locked to a single microwave reference at around 16 GHz, but on different sideband. The IF of 90 MHz is passed to a lock-in amplifier that measures phase and amplitude. Figure 1 shows preliminary results of the near field beam pattern (at 826 GHz) of a corrugated horn made by conventional electro-forming. The far-field beam pattern calculated from the phase and amplitude data showed good agreement with the theoretical one. The measurements at 860 and 896 GHz also showed symmetrical beam pattern as predicted. By using this system, we will test another corrugated horn made by direct machining suited for series production for the ALMA receivers.

Uzawa, Y.; Sugimoto, M.; Kimura, K.; Nohara, R.; Manabe, T.; Ogawa, H.; Fujii, Y.; Shan, W.-L.; Kroug, M.; Shitov, S.

216

Quantitative allocation of Bragg scattering effects in highly efficient OLEDs fabricated on periodically corrugated substrates.  

PubMed

Bragg scattering effects in bottom-emitting organic light-emitting diodes (OLEDs) grown on corrugated aluminum-doped zinc oxide electrodes are analyzed. Periodic corrugation is introduced by structuring the oxide electrode via UV laser ablation, a process that enables flexible adjustment of the period and height of corrugation. We demonstrate that fabrication of stable and electrically efficient OLEDs on these rough substrates is feasible. Sharp spectral features are superimposed onto the broad emission spectra of the OLEDs, providing clear evidence for Bragg scattering of light from guided modes into the air cone. Theoretical analysis based on an emissive dipole model and conservation of momentum considerations allows a quantitative description of scattering and the associated dispersion relations. PMID:23938484

Fuchs, C; Schwab, T; Roch, T; Eckardt, S; Lasagni, A; Hofmann, S; Lssem, B; Mller-Meskamp, L; Leo, K; Gather, M C; Scholz, R

2013-07-15

217

Study of structurally efficient graphite-thermoplastic trapezoidal-corrugation sandwich and semisandwich panels  

NASA Astrophysics Data System (ADS)

The structural efficiency of compression-loaded trapezoidal-corrugation sandwich and semisandwich 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 semisandwich 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 3000 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.

Jegley, Dawn C.

1994-03-01

218

Weakly localized waves on the corrugated surface of a medium of arbitrary anisotropy  

PubMed

The existence of weakly localized surface and pseudosurface waves on the corrugated surface of a medium of arbitrary symmetry is studied. The localized solution originates from an exceptional bulk wave associated with a transonic state of positive or negative curvature. It is shown that the period of corrugation or the frequency of the wave can universally be chosen such that the solution will exist. The range of permissible periods (frequencies) is different for positive and negative curvature transonic states, it being wider near transonic states of positive curvature. The imaginary component of the pseudosurface wave velocity is found to vary as the height of grooves to period of corrugation ratio raised in fourth or sixth power, depending on the transonic state with which the exceptional wave is associated. A simple analytical expression is derived allowing estimations to be made of the penetration depth and the velocity of the localized wave. PMID:10830367

Darinskii

2000-05-01

219

Electronic and geometric corrugation of periodically rippled, self-nanostructured graphene epitaxially grown on Ru(0001)  

NASA Astrophysics Data System (ADS)

Graphene epitaxially grown on Ru(0001) displays a remarkably ordered pattern of hills and valleys in scanning tunneling microscopy (STM) images. The extent to which the observed 'ripples' are structural or electronic in origin has been much disputed recently. A combination of ultrahigh-resolution STM images and helium atom diffraction data shows that (i) the graphene lattice is rotated with respect to the lattice of Ru and (ii) the structural corrugation as determined from He diffraction is substantially smaller (0.15 ) than predicted (1.5 ) or reported from x-ray diffraction or low-energy electron diffraction. The electronic corrugation, on the contrary, is strong enough to invert the contrast between hills and valleys above +2.6 V as new, spatially localized electronic states enter the energy window of the STM. The large electronic corrugation results in a nanostructured periodic landscape of electron and hole pockets.

Borca, Bogdana; Barja, Sara; Garnica, Manuela; Minniti, Marina; Politano, Antonio; Rodriguez-Garca, Josefa M.; Hinarejos, Juan Jose; Faras, Daniel; Vzquez de Parga, Amadeo L.; Miranda, Rodolfo

2010-09-01

220

Gas pipe explorer robot  

NASA Technical Reports Server (NTRS)

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.

Wilcox, Brian (Inventor)

2004-01-01

221

Flexible ultrasonic pipe inspection apparatus  

DOEpatents

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.

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

1994-01-01

222

Experimenting with a "Pipe" Whistle  

ERIC Educational Resources Information Center

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

Stafford, Olga

2012-01-01

223

Graphene on Ru(0001) Moire Corrugation Studied by Scanning Tunneling Microscopy on Au/Graphene/Ru(0001) Heterostructures  

E-print Network

Graphene on Ru(0001) Moire Corrugation Studied by Scanning Tunneling Microscopy on Au/Graphene on graphene/Ru(0001) were used to study the corrugation of the moire structure of graphene/Ru(0001 for the graphene/Ru(0001) moire is of structural nature rather than electronic. STM showed a large value

Ciobanu, Cristian

224

Heat Transfer Coefficient and Friction Factor Prediction of Corrugated Tubes Combined With Twisted Tape Inserts Using Artificial Neural Network  

Microsoft Academic Search

In the research described here, artificial neural network (ANN) approach has been utilized to characterize the thermohydraulic behavior of corrugated tubes combined with twisted tape inserts in a turbulent flow regime. The experimental data sets were extracted from 57 tubes, 9 and 3 spirally corrugated tubes with varying geometries combined with 5 and 4 twisted tapes with different pitches. The

Mohammad Reza Jafari Nasr; Ali Habibi Khalaj

2010-01-01

225

Structural properties of superplastically formed/diffusion-bonded orthogonally corrugated core sandwich plates  

NASA Technical Reports Server (NTRS)

This paper describes a new superplastically formed/diffusion-bonded (SPF/DB) orthogonally corrugated sandwich structure, and presents formulae and the associated plots for evaluating the effective elastic constants for the core of this new sandwich structure. Comparison of structural properties of this new sandwich structure with the conventional honeycomb core sandwich structure was made under the condition of equal sandwich density. It was found that the SPF/DB orthogonally corrugated sandwich core has higher transverse shear stiffness than the conventional honeycomb sandwich core. However, the former has lower stiffness in the sandwich core thickness direction than the latter.

Ko, W. L.

1980-01-01

226

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

NASA Technical Reports Server (NTRS)

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.

Ko, W. L.

1980-01-01

227

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

NASA Technical Reports Server (NTRS)

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.

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

1984-01-01

228

Comparison of heat transfer in straight and corrugated minichannels with two-phase flow  

NASA Astrophysics Data System (ADS)

Measurements of heat transfer rates performed with an experimental condensation heat exchanger are reported for a corrugated minichannel tube and for a straight minichannel tube. The two cases were compared at same flow regimes. The corrugation appears advantageous for relatively low steam pressures and flow rates where much higher heat transfer rates were observed close to the steam entrance, thus allowing shortening the heat exchanger with the associated advantages of costs lowering and smaller built-up space. At high steam pressures and high flow rates both tubes performed similarly.

Peukert, P.; Hrub, J.

2014-03-01

229

Laterally-corrugated ridge-waveguide distributed feedback lasers at 980nm  

Microsoft Academic Search

The paper presents a simulation-based analysis of laterally-corrugated ridge-waveguide distributed feedback semiconductor\\u000a lasers emitting at 980nm. The simulations were performed using software developed in-house and the PICS3D software package\\u000a from Crosslight Software Inc. The effects of the corrugation geometry, phase-shift section, and mirror reflectivities on single\\u000a longitudinal mode operation are discussed. The lasers, designed along the guidelines derived from the

Antti Laakso; Mihail Dumitrescu; Jukka Viheril; Jarkko Telkkl; Juha Tommila; Kimmo Haring; Tomi Leinonen; Sanna Ranta; Markus Pessa

2009-01-01

230

Improved Thin, Flexible Heat Pipes  

NASA Technical Reports Server (NTRS)

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.

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

2004-01-01

231

Heat pipe manufacturing study  

NASA Technical Reports Server (NTRS)

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.

Edelstein, F.

1974-01-01

232

Miniature pipe crawler tractor  

DOEpatents

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.

McKay, Mark D. (Idaho Falls, ID); Anderson, Matthew O. (Idaho Falls, ID); Ferrante, Todd A. (Westerville, OH); Willis, W. David (Idaho Falls, ID)

2000-01-01

233

Heat pipe development  

NASA Technical Reports Server (NTRS)

The objective of this program was to investigate analytically and experimentally the performance of heat pipes with composite wicks--specifically, those having pedestal arteries and screwthread circumferential grooves. An analytical model was developed to describe the effects of screwthreads and screen secondary wicks on the transport capability of the artery. The model describes the hydrodynamics of the circumferential flow in triangular grooves with azimuthally varying capillary menisci and liquid cross-sections. Normalized results were obtained which give the influence of evaporator heat flux on the axial heat transport capability of the arterial wick. In order to evaluate the priming behavior of composite wicks under actual load conditions, an 'inverted' glass heat pipe was designed and constructed. The results obtained from the analysis and from the tests with the glass heat pipe were applied to the OAO-C Level 5 heat pipe, and an improved correlation between predicted and measured evaporator and transport performance were obtained.

Bienart, W. B.

1973-01-01

234

Flexible drill pipe  

SciTech Connect

A flexible pipe is described which consists of: an elongated tubular member subdivided into a plurality of segments of rigid pipe of substantial wall thickness in end-to-end relationship with a plurality of interlocking teeth and complementary recesses on each end of the segments intermediate the ends of the tubular member, the teeth of one segment being positioned in the recesses of, and interlocking the teeth of, the adjacent segment with sufficient clearance to form a joint permitting limited relative movement between the segments, each of the teeth comprising an arcuate crown portion with its arc extending generally axially of the pipe, a tapered base portion and a substantially flat shoulder area extending between the crown and base portions in a direction generally circumferentially of the pipe.

Hatten, J.L.

1986-07-15

235

Silicon Heat Pipe Array  

NASA Technical Reports Server (NTRS)

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 suited for the cooling of semiconductor devices.

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

2013-01-01

236

Heat pipe dynamic behavior  

NASA Technical Reports Server (NTRS)

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.

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

1988-01-01

237

Heat Pipe Integrated Microsystems  

SciTech Connect

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 the satellite such as solar panels, radiators, antenna and.telescopes (for communications or sensors). Finally, the packages make thermal contact to the surface of the silicon heat pipe through soft thermal pads. Electronic components can be placed on both sides of the flexible circuit interconnect. Silicon heat pipes have a number of advantages over heat pipe constructed from other materials. Silicon heat pipes offer the ability to put the heat pipe structure beneath the active components of a processed silicon wafer. This would be one way of efficiently cooling the heat generated by wafer scale integrated systems. Using this technique, all the functions of a satellite could be reduced to a few silicon wafers. The integration of the heat pipe and the electronics would further reduce the size and weight of the satellite.

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

1999-03-30

238

Phonomyography of the corrugator supercilii muscle: signal characteristics, best recording site and comparison with acceleromyography  

Microsoft Academic Search

Background. This study investigated the acoustic signal characteristics and best recording site of phonomyography at the corrugator supercilii muscle and compared phonomyography with acceleromyography. Methods. In 12 patients (group I), after induction of anaesthesia and insertion of a laryngeal mask, a microphone (frequency range 2.5 Hz to 10 kHz) was placed on six different areas on the forehead and the

T. M. Hemmerling; F. Donati; P. Beaulieu; D. Babin

2002-01-01

239

Heat transfer analysis using ANNs with experimental data for air flowing in corrugated channels  

Microsoft Academic Search

The objective of this work is to use artificial neural networks (ANNs) for heat transfer analysis in corrugated channels. A data set evaluated experimentally is prepared for processing with the use of neural networks. Back propagation algorithm, the most common learning method for ANNs, was used in training and testing the network. To solve this algorithm a computer program using

Y. Islamoglu; A. Kurt

2004-01-01

240

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

DOEpatents

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.

Fischer, William H. (Pittsburgh, PA); Yoon, Kue H. (Pittsburgh, PA)

1984-04-10

241

Convective heat transfer and pressure drop in V-corrugated channel with different phase shifts  

NASA Astrophysics Data System (ADS)

New energy system development and energy conservation require high performance heat exchanger, so the researchers are seeking to find new methods to enhance heat transfer mechanism in heat exchangers. The objectives of this study are investigating heat transfer performance and flow development in V-corrugated channels, numerical simulations were carried out for uniform wall heat flux equal 290 W/m2 using air as a working fluid, Reynolds number varies from 500 to 2,000, phase shifts, 0 < < 180, and channel heights (S = 12.5, 15.0, 17.5 and 20 mm). Governing equations of flow and energy were solved numerically by using finite volume method. The numerical results indicated that, wavy (V-corrugated) channels have a significant impact on heat transfer enhancement with increase in pressure drop though channel due to breaking and destabilizing in the thermal boundary layer are occurred as fluid flowing through the corrugated surfaces and the effect of corrugated phase shift on the heat transfer and fluid flow is more significant in narrow channel, the goodness factor (j/f) was increased with increasing channel phase shift, the best performance was noticed on phase shift, = 180 and channel height, S = 12.5 mm.

Sakr, Mohamed

2014-07-01

242

Shear band blocking in explosively driven collapse of corrugated Ni-Al laminate cylinder  

NASA Astrophysics Data System (ADS)

Ni-Al laminate materials have been identified as a possible material system that can be used as a reactive material due to the self-sustaining reaction between Al and Ni layers. Besides traditional ignition methods, shear bands developed during mechanical loading can provide sites where ignition can occur. Corrugated Ni-Al laminate samples were created by swaging alternating layers of Ni (20 micrometers thick) and Al (30 micrometers thick) foils. The thick-walled cylinder (TWC) technique was performed on a corrugated Ni-Al laminate cylinder sample to examine shear band development in this material. Post experiment examination of the corrugated Ni-Al laminate material showed that the development of global shear bands were blocked via mesoscale mechanisms. The collapse of the corrugated laminate cylinder was simulated providing insight into these mesoscale mechanisms that were involved in blocking the development of shear bands during the experiment. Despite the shear band resistance of the material, several regions of the sample had localized reactions of Al and Ni spanning approximately 10-20 layers of laminate.

Olney, Karl; Chiu, Po-Hsun; Higgins, Andrew; Serge, Matthew; Fritz, Gregory; Stover, Adam; Nesterenko, Vitali; Benson, David

2013-03-01

243

Experimental and theoretical investigation of the angular dependence of the Casimir force between sinusoidally corrugated surfaces  

NASA Astrophysics Data System (ADS)

In the current work we present the complete results for the measurement of normal Casimir force between a shallow and smooth sinusoidally corrugated gold coated sphere and a plate at various angles between the corrugations using an atomic force microscope. All measured data were compared with the theoretical approach using the proximity force approximation and theory based on derivative expansion. In both cases real material properties of the surfaces and nonzero temperature were taken into account. Special attention is paid to the description of electrostatic interactions between corrugated surfaces at different angles between corrugations and samples preparation and characterization. The measured forces are found to be in good agreement with the theory including correlation effects of geometry and material properties and deviate significantly from the predictions of the proximity force approximation approach. This provides the quantitative confirmation for the observation of diffraction-type effects that are disregarded within the PFA approach. The obtained results open new opportunities for control of the Casimir effect in micromechanical systems.

Banishev, A. A.; Wagner, J.; Emig, T.; Zandi, R.; Mohideen, U.

2014-06-01

244

Thermal Stability of Corrugated Epitaxial Graphene Grown on Re(0001) E. Miniussi,1,2  

E-print Network

, the high- temperature formation of lattice defects is a key issue to understand the thermally driven, the high-temperature formation of periodic rip- ples in GR is regarded as a new way to tailor the transport that the accurate determination of GR corrugation is a key point to shed light on the GR-substrate interaction

Alfè, Dario

245

Pressure Drop in Multi-Parallel Channels of Corrugated Plate Steam Condensers  

Microsoft Academic Search

An experimental investigation has been carried out to find the pressure difference of the process of steam condensation across the port to channel in plate heat exchangers. In the present study, low corrugation angle (30) plates have been used for different number of channels, namely, 10 and 80. The process steam entered at 1 bar with a small degree of

Prabhakara Rao Bobbili; Bengt Sunden

2009-01-01

246

Negative linear classical magnetoresistance in a corrugated two-dimensional electron gas N. M. Sotomayor*  

E-print Network

to non-Markovian memory effects originated by specific return processes in backscattering of electronsNegative linear classical magnetoresistance in a corrugated two-dimensional electron gas N. M) was measured in a GaAs/AlxGa1-xAs two-dimensional electron system with nonplanar topography, caused by random

Gusev, Guennady

247

Classical Theory of Atom Scattering from Corrugated Surfaces W. W. Hayes  

E-print Network

Classical Theory of Atom Scattering from Corrugated Surfaces W. W. Hayes Physical Sciences phonon transfers. In the classical limit the theory produces an expression that includes the effects A theory based in the semiclassical eikonal approximation is developed to describe energy trans- fer

Manson, Joseph R.

248

Terahertz Surface Plasmon-Polariton Propagation and Focusing on Periodically Corrugated Metal Wires  

Microsoft Academic Search

In this Letter, we show how the dispersion relation of surface plasmon polaritons (SPPs) propagating along a perfectly conducting wire can be tailored by corrugating its surface with a periodic array of radial grooves. In this way, highly localized SPPs can be sustained in the terahertz region of the electromagnetic spectrum. Importantly, the propagation characteristics of these spoof SPPs can

Stefan A. Maier; Steve R. Andrews; L. Martn-Moreno; F. J. Garca-Vidal

2006-01-01

249

Effect of absorption on terahertz surface plasmon polaritons propagating along periodically corrugated metal wires  

Microsoft Academic Search

In this paper, a rigorous method for analyzing surface plasmon polaritons (SPPs) on a periodically corrugated metal wire has been formulated, based on a modal expansion of electromagnetic fields. Compared with the previous method, our method takes into account the finite conductivity of the wire as well as higher-order modes within the wire grooves in the expansion, thus is able

Linfang Shen; Xudong Chen; Yu Zhong; Krishna Agarwal

2008-01-01

250

Design study of Corrugated Waveguide Slow-Wave Structure for THz amplification  

Microsoft Academic Search

THz Vacuum devices require high precision technological processes, but fabrication tolerances could highly affect the overall performances. Therefore a statistical analysis is fundamental for a reliable design. In this abstract, it is proposed a study on a Corrugated Waveguide Slow-Wave Structure for Traveling Wave Tubes in the THz region. An analytical model is validated by three dimensional electromagnetic softwares, both

Mauro Mineo; Claudio Paoloni

2009-01-01

251

REALIZATION OF CORRUGATED LONG-PERIOD GRATINGS IN SILICA-BASED OPTICAL WAVEGUIDES  

Microsoft Academic Search

Long-period corrugated gratings realized in silica-based optical waveguides have been presented. Following design optimization, waveguide gratings were fabricated through various process steps like PECVD, photolithography, metallization, lift-off, deep\\/shallow RIE, etc. Waveguide and grating parameters were so chosen that the resonance wavelength of gratings could be achieved at ~ 1.55 ?m.

Suchandan Pal; Ashok Chauhan; Pawan Kumar; Mahendra Singh; Nirmal Pradhan; Mukesh K Sharma; Basant K Sahu; Kuldip Singh; C Dhanavantri

2008-01-01

252

Fabrication of waveguide grating coupler with double-corrugation by ion beam etching technology  

Microsoft Academic Search

This paper reports the method and technology on the fabrication of grating coupler with double-corrugation on BK7 glass waveguide for operation at 780 nm wavelength. Twice ion beam etching has technologically made possible the fabrication of high-efficiency waveguide grating coupler.

Y. J. Li; Mai Xu; Olivier M. Parriaux

1994-01-01

253

Corrugated waveguide slow-wave structure for THz travelling wave tube  

Microsoft Academic Search

THz applications require sources and amplifiers compact, lightweight and powerful. Vacuum electron devices are the candidate solution. Among others, the corrugated waveguide slow-wave structure seems particularly suitable for traveling wave tubes in the THz region. THz vacuum electron devices require high precision technological processes with high aspect ratio such as SU-8 process. However, fabrication tolerances could highly affect the overall

Mauro Mineo; Claudio Paoloni; Aldo Di Carlo; Anna Maria Fiorello; Massimiliano Dispenza

2009-01-01

254

Fabrication of waveguide grating coupler with double corrugation by ion-beam etching technology  

NASA Astrophysics Data System (ADS)

This paper reports the method and technology on the fabrication of grating coupler with double-corrugation on BK7 glass waveguide for operation at 780 nm wavelength. Twice ion beam etching has technologically made possible the fabrication of high-efficiency waveguide grating coupler.

Li, Yajun; Xu, Mai; Parriaux, Olivier M.

1994-08-01

255

Binderless fiberboard: Comparison of fiber from recycled corrugated containers and refined small-diameter whole treetops  

Microsoft Academic Search

Whereas many research activities focus on developing value-added processes that use forest residues, scientists must also investigate the mechanical properties of products made from recycled fiber resources. This study compared the tensile and bending properties of binderless panels made from recycled corrugated containers with properties of panels made from lodgepole pine treetop residues. The properties were measured after reaching equilibrium

John F. Hunt; Karen Supan

256

Numerical simulation of flow of shear-thinning fluids in corrugated channels  

E-print Network

A numerical study of flow of a shear thinning fluid through a pair of corrugated plates was carried out. The aim of the study was to observe and understand the behavior of the flow of shear thinning fluids through channels were the fluid...

Aiyalur Shankaran, Rohit

2009-05-15

257

Failure modes and design optimization for re-usable corrugated cases  

E-print Network

The objective of this thesis is to study and analyze the distribution and usage of reusable corrugated cardboard cases in the delivery of the product within the Frito-Lay system. The studies conducted looked at the various modes by which the cases...

Karuppoor, Srinand S.

2012-06-07

258

Numerical simulation of flow of shear-thinning fluids in corrugated channels  

E-print Network

A numerical study of flow of a shear thinning fluid through a pair of corrugated plates was carried out. The aim of the study was to observe and understand the behavior of the flow of shear thinning fluids through channels were the fluid...

Aiyalur Shankaran, Rohit

2008-10-10

259

Response of Corrugated Fiberboard to Moisture Flow: A 3-D Finite Element Transient Nonlinear Analysis  

Microsoft Academic Search

Collapse of fiberboard packaging boxes, in the shipping indus- try, due to rise in humidity conditions is common and very cost- ly. A 3D FE nonlinear model is developed to predict the moisture flow throughout a corrugated packaging fiberboard sandwich structure. The model predicts how the moisture diffu- sion will permeate through the layers of a fiberboard (medium and facings).

Adeeb A. Rahman; Thomas J. Urbanik

260

Detachment Faulting Within Slow-Spreading Segments - Beyond the Corrugated Surface.  

NASA Astrophysics Data System (ADS)

Acoustic mapping of slow-spreading ridges has revealed that some but not all inside corner massifs are topped by corrugated surfaces. These surfaces are interpreted as the exhumed slip surface of large offset normal faults. As with all faults, the extent of fault exposure in the transport direction represents a minimum estimate of the displacement along the fault. However, whereas most normal faults have displacements that are only a fraction of their along-strike extent to maintain strain compatibility, the corrugated surfaces are commonly close to equidimensional and in some cases are longer in the displacement direction. In some cases the corrugated surface is terminated laterally by transform or other structures (e.g. the Ascension transform - studied during Meteor cruise 62-4, October 2004), but in others no such clear truncation can be observed, causing potential strain compatibility problems. One solution is that the corrugated surface does not represent the full along strike length of the faults. Seismic images of Cretaceous oceanic crust image at inside corners detachment faults that follow top basement and image elsewhere detachment faults buried beneath a layer of fault blocks. We suggest that these apparently different types of detachment may be different parts of one type, i.e. that the corrugated surfaces continue along strike toward the segment middle beneath a layer of small fault blocks. This is consistent with observations made from bathymetric mapping at the current spreading center. The varying exposure of the detachment fault can be explained by a rolling hinge model in which the flexing fault becomes inactive either after it has been exhumed, or in the sub-surface. The former results in the exposure of the footwall as a corrugated surface, the latter requires new faults to cut up through the hangingwall and transfer fault slices to the footwall. As a result, the footwall is buried beneath a layer of such fault slices. We suggest that the variation in the depth at which the fault becomes inactive is controlled by the along segment variation in both lithospheric structure and the rheology of the fault zones. The model also explains why not all inside corner massifs exhibit corrugated surfaces: the exposure of such a surface relies not only on the development of an appropriate fault system, but also on the exhumation of the footwall of the fault. Another implication is that detachment faulting may be important along much of some spreading segments and that tectonic strain may be more important at segment centers than previously suggested.

Reston, T. J.; Ranero, C. R.

2005-12-01

261

The diffraction of ultrasound on corrugated surfaces and its possible application for surface wave stimulation  

NASA Astrophysics Data System (ADS)

This paper describes some achievements in the field of the diffraction of ultrasound on corrugated surfaces. Both single and double corrugated surfaces are considered. A demonstration of the capability of the inhomogeneous wave theory to simulate backward displacement of ultrasonic bounded beams (observed by Breazeale and Torbett, Appl. Phys. Let. 29(8), 456-458, 1976) has been demonstrated very recently [Nico F. Declercq, Joris Degrieck, Rudy Briers, Oswald Leroy, Appl. Phys. Let. 82(15), 2533-2534, 2003]. The current report applies the theory of the diffraction of inhomogeneous waves and shows how this theory is capable of simulating, explaining and understanding the experiments mentioned above. The theory reveals the existence of leaky Scholte - Stoneley waves, which is a novel phenomenon that was first reported from a theoretical point of view [Nico F. Declercq, Joris Degrieck, Rudy Briers, Oswald Leroy, J. Acoust. Soc. Am. 112(5), 2414, 2002] and was shortly after discovered experimentally [A.A. Teklu, M.A. Breazeale, J. Acoust. Soc. Am. 113(4), 2283-2284, 2003]. Moreover, the present paper shows that the classical Fourier decomposition of bounded beams is unable to simulate the backward beam displacement. This work also elucidates the nature of Wood anomalies in Diffraction spectra. Furthermore, it is known that singly corrugated surfaces have the ability to stimulate surface acoustic waves by means of diffraction. However, this diffraction occurs in a single plane. Sound impinging a doubly corrugated surface is scattered in many directions. Therefore, such surfaces possess the ability to generate surface waves in many directions, depending on the corrugation and depending on the frequency. Numerical simulation is possible if continuity of stress and strain is considered. The present paper reports advanced numerical simulations based on all physical parameters of the system and shows what surface waves are generated, under what conditions and under what angle. Such a device may be used to send surfaces in directions that are determined by their frequency.

Declercq, Nico F.; Briers, Rudy; Degrieck, Joris; Leroy, Oswald

2005-03-01

262

Heat Pipe Technology  

NASA Technical Reports Server (NTRS)

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.

1981-01-01

263

Apparatus for inspecting piping  

DOEpatents

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.

Zollingger, W. Thor (Martinez, GA); Appel, D. Keith (Aiken, SC); Park, Larry R. (Raleigh, NC)

1995-01-01

264

Heat-pipe Earth.  

PubMed

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

Moore, William B; Webb, A Alexander G

2013-09-26

265

Composite drill pipe  

DOEpatents

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.

Leslie, James C. (Fountain Valley, CA); Leslie, II, James C. (Mission Viejo, CA); Heard, James (Huntington Beach, CA); Truong, Liem (Anaheim, CA), Josephson; Marvin (Huntington Beach, CA), Neubert; Hans (Anaheim, CA)

2008-12-02

266

49 CFR 230.62 - Dry pipe.  

Code of Federal Regulations, 2010 CFR

...TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS...Appurtenances Steam Pipes 230.62 Dry pipe. Dry pipes subject to pressure...examined at each annual inspection to measure wall thickness. Dry pipes with wall...

2010-10-01

267

46 CFR 76.33-15 - Piping.  

Code of Federal Regulations, 2011 CFR

...Piping. (a) Individual pipes shall be not less than 3/4 -inch standard pipe size. (b) All piping...drainage. (e) Drains and dirt tapes shall be fitted where...prevent the accumulation of dirt or...

2011-10-01

268

46 CFR 76.33-15 - Piping.  

Code of Federal Regulations, 2010 CFR

...Piping. (a) Individual pipes shall be not less than 3/4 -inch standard pipe size. (b) All piping...drainage. (e) Drains and dirt tapes shall be fitted where...prevent the accumulation of dirt or...

2010-10-01

269

Tippy Tap Plus Piping  

NSDL National Science Digital Library

The Tippy Tap hand-washing station is an inexpensive and effective device used extensively in the developing world. One shortcoming of the homemade device is that it must be manually refilled with water and therefore is of limited use in high-traffic areas. In this activity, student teams design, prototype and test piping systems to transport water from a storage tank to an existing Tippy Tap hand-washing station, thereby creating a more efficient hand-washing station. Through this example service-learning engineering project, students learn basic fluid dynamic principles that are needed for creating efficient piping systems.

Integrated Teaching and Learning Program, College of Engineering, University of Colorado at Boulder,

270

Heat pipe array heat exchanger  

DOEpatents

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.

Reimann, Robert C. (Lafayette, NY)

1987-08-25

271

Pipe Drafting with CAD. Teacher Edition.  

ERIC Educational Resources Information Center

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

Smithson, Buddy

272

Heat pipe turbine vane cooling  

Microsoft Academic Search

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

L. Langston; A. Faghri

1995-01-01

273

Acme jumper pipe  

SciTech Connect

Acme Steel had operated the larry car with an attached jumper pipe since 1977. Acme had been able to meet the State Implementation Plan. With the advent of the Clean Air Act, Acme did not feel it could meet these new standards without some modifications to the jumper pipe system. Several drop sleeve modifications and numerous boot seal materials and configurations were tested that resulted in limited success in improving the boot seal life. After these modifications, Acme`s testing revealed it could meet the Clean Air Act standards, but it would be cost prohibitive to continue to operate in this manner. Following extensive investigation, Acme decided to install an off-car jumper pipe system which uses a traveling U-tube for connecting to the assist oven through an additional hole in each oven roof. Temperature related failures of drop sleeve seals were eliminated. The off-car jumper pipe is a more efficient gas connection to the assist oven and enables Acme to meet the Clean Air Act charging requirements in a cost effective manner.

Medved, P.; Thomas, H. [Acme Steel Co., Chicago, IL (United States)

1995-09-01

274

A Dual Resonant Microstrip Antenna for UHF RFID in the Cold Chain Using Corrugated Fiberboard as a Substrate  

E-print Network

fiberboard boxes that are ubiquitous in the supply chain. Commercially available passive UHF RFID tags are either sensitive to the content/environmental conditions of the corrugated fiberboard box or economically unfeasible. In this thesis we propose a novel...

Sivakumar, Mutharasu

2008-02-01

275

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

DOEpatents

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.

Fischer, William H. (Pittsburgh, PA); Cookson, Alan H. (Pittsburgh, PA); Yoon, Kue H. (Pittsburgh, PA)

1984-04-10

276

A Composite Right\\/Left-Handed Rectangular Waveguide with Tilted Corrugations for Millimeter-wave Frequency Scanning Antenna  

Microsoft Academic Search

A novel structure for a composite right\\/left-handed (CRLH) corrugated waveguide that operates in the millimeter-wave band is proposed. The CRLH waveguide is comprised of a rectangular waveguide which has tilted corrugations on its bottom broad wall. By operating both above and below the cutoff frequency of the dominant mode, the rectangular waveguide provides, respectively, an inherent series inductance and shunt

Toru Iwasaki; Hirokazu Kamoda; Thomas Derham; Takao Kuki

2008-01-01

277

Heat Pipes Cool Power Magnetics  

NASA Technical Reports Server (NTRS)

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.

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

1983-01-01

278

Buckling test of a 3-meter-diameter corrugated graphite-epoxy ring-stiffened cylinder  

NASA Technical Reports Server (NTRS)

A three m diameter by three m long corrugated cylindrical shell with external stiffening rings was tested to failure by buckling. The corrugation geometry for the graphite epoxy composite cylinder wall was optimized to withstand a compressive load producing an ultimate load intensity of 157.6 kN/m without buckling. The test method used to produce the design load intensity was to mount the specimen as a cantilevered cylinder and apply a pure bending moment to the end. A load introduction problem with the specimen was solved by using the BOSOR 4 shell of revolution computer code to analyze the shell and attached loading fixtures. The cylinder test loading achieved was 101 percent of design ultimate, and the resulting mass per unit of shell wall area was 1.96 kg/sq m.

Davis, R. C.

1982-01-01

279

Inelastic molecule-corrugated surface scattering using the close-coupling wave-packet method  

Microsoft Academic Search

A computer program for calculating transition probabilities for rotationally and translationally inelastic scattering of homonuclear diatomic molecules from static, corrugated surfaces is described. The program uses an exact quantum-mechanical method which combines a close-coupling expansion of the internal states with a time-dependent wave-packet description of the center-of-mass motion. The wave function is propagated in time using an expansion of the

R. C. Mowrey; D. J. Kouri

1991-01-01

280

Dynamical modeling and experimental validation of a micro-speaker with corrugated diaphragm for mobile phones  

Microsoft Academic Search

As the design trend of modern cellular phones evolves to be miniaturization and versatile sound in quality, the electro-mechanical\\u000a components including the micro-speaker are essential toward size reduction and broad frequency range of sound. To reduce size,\\u000a a diaphragm type micro-speaker is commonly employed in industry, while to broaden the sound frequency range corrugations on\\u000a the diaphragm are adopted. The

Paul C.-P. Chao; I-Ting Wang

2007-01-01

281

Phase space tomography of cold-atom dynamics in a weakly corrugated potential  

NASA Astrophysics Data System (ADS)

We demonstrate tomographic reconstruction of the phase space distribution of atoms oscillating in a harmonic trap with weak potential corrugation caused by nanoscale imperfections in an atom chip. We find that deformations in these distributions are highly sensitive to anharmonic components of the potential. They are explained in terms of angular velocity dispersion of isoenergetic phase space trajectories. We show that the method is applicable for probing classical and quantum dynamics of cold atoms, and we note its importance for future technological applications.

Zhou, Shuyu; Chab, Julien; Salem, Ran; David, Tal; Groswasser, David; Keil, Mark; Japha, Yonathan; Folman, Ron

2014-09-01

282

Phase space tomography of cold-atoms dynamics in a weakly corrugated potential  

E-print Network

We demonstrate tomographic reconstruction of the phase space distribution of atoms oscillating in a harmonic trap with weak potential corrugation caused by nanoscale imperfections in an atom chip. We find that deformations in these distributions are highly sensitive to anharmonic components of the potential. They are explained in terms of angular velocity dispersion of isoenergetic phase space trajectories. We show that the method is applicable for probing classical and quantum dynamics of cold atoms, and we note its importance for future technological applications.

Shuyu Zhou; Julien Chab; Ran Salem; Tal David; David Groswasser; Mark Keil; Yonathan Japha; Ron Folman

2014-03-13

283

Ohmic losses in coaxial resonators with longitudinal inner-outer corrugation  

SciTech Connect

In this paper, a coaxial resonator with longitudinal inner-outer corrugation is introduced. Its eigen-equation and expression of ohmic losses are derived. Ohmic losses in the cavity are investigated. Results show that ohmic losses in the outer and inner conductors share a similar variation trend, while the former is larger than the later. What's more, changes of the inner and outer slot depth and width induce different variations of ohmic losses on the surface of the inner and outer conductors.

Shenyong Hou, A. [Terahertz Science and Technology Research Center, University of Electronics Science and Technology of China, Chengdu 610054 (China) [Terahertz Science and Technology Research Center, University of Electronics Science and Technology of China, Chengdu 610054 (China); Yangtze Normal University, Chongqing 408001 (China); Sheng Yu, B.; Hongfu Li, C.; Qixiang Zhao, D. [Terahertz Science and Technology Research Center, University of Electronics Science and Technology of China, Chengdu 610054 (China)] [Terahertz Science and Technology Research Center, University of Electronics Science and Technology of China, Chengdu 610054 (China); Xiang Li, E. [Terahertz Science and Technology Research Center, University of Electronics Science and Technology of China, Chengdu 610054 (China) [Terahertz Science and Technology Research Center, University of Electronics Science and Technology of China, Chengdu 610054 (China); Queen Mary University of London, London E1 4NS (United Kingdom)

2013-05-15

284

Terahertz Surface Plasmon-Polariton Propagation and Focusing on Periodically Corrugated Metal Wires  

Microsoft Academic Search

In this letter we show how the dispersion relation of surface plasmon\\u000apolaritons (SPPs) propagating along a perfectly conducting wire can be tailored\\u000aby corrugating its surface with a periodic array of radial grooves. In this\\u000away, highly localized SPPs can be sustained in the terahertz region of the\\u000aelectromagnetic spectrum. Importantly, the propagation characteristics of these\\u000aspoof SPPs can

Stefan A. Maier; Steve R. Andrews; L. Martn-Moreno; F. J. Garca-Vidal

2006-01-01

285

Integration of a multimode interference coupler with a corrugated sidewall Bragg grating in planar polymer waveguides  

Microsoft Academic Search

We demonstrate the integration of a 3-dB multimode interference coupler with a corrugated sidewall Bragg grating in planar polymer waveguides by direct electron beam writing. Both transmission and reflection spectra of the Bragg grating are measured through this integrated device directly. We use the thermooptic effect to tune the integrated waveguide grating, achieving a tuning range of 6.2 nm and

Lin Zhu; Yanyi Huang; Amnon Yariv

2006-01-01

286

Distributed-feedback terahertz quantum-cascade lasers with laterally corrugated metal waveguides  

Microsoft Academic Search

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

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

2005-01-01

287

Analysis and Design of Corrugated Long-Period Gratings in Silica-on-Silicon Planar Waveguides  

Microsoft Academic Search

A detailed theoretical analysis on light transmission through a corrugated long-period waveguide grating made in a silica-on-silicon planar waveguide is presented. A grating period of ~280 mum is considered in order to achieve a strong rejection band at a wavelength region of 1.5 mum. Phase-matching graphs are studied to find the relationship between the resonance wavelength and the grating period.

Suchandan Pal; Babu Ram Singh

2007-01-01

288

Corrugated circular coaxial waveguide and EM wave generator for use in satellite communications  

Microsoft Academic Search

The design, simulation and fabrication of a dual band waveguide structure for the direct broadcast satellite (DBS) market is presented. Using two frequency bands under study; 19.720.2 and 29.530 GHz, we have created a corrugated waveguide structure with a second higher band waveguide nested inside the outer waveguide. The design and simulation was carried out using CST's Microwave Studio 2010

R. Todd; D. Linton; G. Stafford; T. Huang

2011-01-01

289

Distributed-feedback terahertz quantum-cascade lasers using laterally corrugated metal waveguides  

Microsoft Academic Search

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

Sushil Kumar; John Louis Reno; Benjamin S. Williams; Qing Hu

2005-01-01

290

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

NASA Astrophysics Data System (ADS)

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.

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

2014-07-01

291

Effect of board density on bending properties and dimensional stabilities of MDF-reinforced corrugated particleboard  

Microsoft Academic Search

We investigated the bending properties of composite boards produced by reinforcing both sides of corrugated particleboard with medium-density fiberboard (MDF). Thickness swelling and linear expansion (LE) were measured to assess the dimensional stabilities of the composite board. Although the apparent density of the composite board was 0.48?g\\/cm 3, its strength was found to be equivalent to that of 18-type particleboard

Koji Hayashi; Masaharu Ohmi; Hiroshi Tominaga; Kiyoharu Fukuda

2003-01-01

292

Evaluation of a tri-wall corrugated fibreboard package for packaging and transporting LSA nonretrievable waste  

Microsoft Academic Search

An evaluation was conducted to determine if an economical Tri-Wall Corrugated Fiberboard (TWCF) Package could be used for transporting LSA nonretrievable wastes (< 10 nCi\\/g radioactive contamination). A complete description of the packaging configuration was given. The evaluation included Vibration Tests to determine if the TWCF Package would comply with the present DOT regulation for packaging LSA waste (i.e. the

D. M. Saiki; P. G. Aguilar

1981-01-01

293

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

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

294

Five orders of magnitude reduction in energy coupling across corrugated graphene/substrate interfaces.  

PubMed

A normal full-contact graphene/substrate interface has been reported to have a thermal conductance in the order of 10(8) Wm(-2)K(-1). The reported work used a sandwiched structure to probe the interface energy coupling, and the phonon behavior in graphene was significantly altered in an undesirable way. Here, we report an intriguing study of energy coupling across unconstrained graphene/substrate interfaces. Using novel Raman-based dual thermal probing, we directly measured the temperature drop across the few nm gap interface that is subjected to a local heat flow induced by a second laser beam heating. The thermal conductance (Gt) for graphene/Si and graphene/SiO2 interfaces is determined as 183 10 and 266 10 Wm(-2)K(-1). At the graphene/Si interface, Gt is 5 orders of magnitude smaller than that of full interface contact. It reveals the remarkable effect of graphene corrugation on interface energy coupling. The measurement result is elucidated by atomistic modeling of local corrugation and energy exchange. By decoupling of graphene's thermal and mechanical behavior, we obtained the stress-induced Raman shift of graphene at around 0.1 cm(-1) or less, suggesting extremely loose interface mechanical coupling. The interface gap variation is evaluated quantitatively on the basis of corrugation-induced Raman enhancement. The interface gap could change as much as 1.8 nm when the local thermal equilibrium is destroyed. PMID:24476126

Tang, Xiaoduan; Xu, Shen; Zhang, Jingchao; Wang, Xinwei

2014-02-26

295

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

NASA Technical Reports Server (NTRS)

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.

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

1985-01-01

296

The weakly nonlinear interfacial stability of a core annular flow in a corrugated tube  

NASA Astrophysics Data System (ADS)

A core annular flow, the concurrent axial flow of two immiscible fluids in a circular tube or pore with one fluid in the core and the other in the wetting annular region, is frequently used to model technologically important flows, e.g. in liquid liquid displacements in secondary oil recovery. Most of the existing literature assumes that the pores in which such flows occur are uniform circular cylinders, and examine the interfacial stability of such systems as a function of fluid and interfacial properties. Since real rock pores possess a more complex geometry, the companion paper examined the linear stability of core annular flows in axisymmetric, corrugated pores in the limit of asymptotically weak corrugation. It found that short-wave disturbances that were stable in straight tubes could couple to the wall's periodicity to excite unstable long waves. In this paper, we follow the evolution of the axisymmetric, linearly unstable waves for fluids of equal densities in a corrugated tube into the weakly nonlinear regime. Here, we ask whether this continual generation of new disturbances by the coupling to the wall's periodicity can overcome the nonlinear saturation mechanism that relies on the nonlinear (kinematic-condition-derived) wave steepening of the Kuramoto Sivashinsky (KS) equation. If it cannot, and the unstable waves still saturate, then do these additional excited waves make the KS solutions more likely to be chaotic, or does the dispersion introduced into the growth rate correction by capillarity serve to regularize otherwise chaotic motions?

Wei, Hsien-Hung; Rumschitzki, David S.

2002-09-01

297

Making angle-resolved photoemission measurements on corrugated monolayer crystals: Suspended exfoliated single-crystal graphene  

NASA Astrophysics Data System (ADS)

Free-standing exfoliated monolayer graphene is an ultrathin flexible membrane, which exhibits out-of-plane deformation or corrugation. In this paper, a technique is described to measure the band structure of such free-standing graphene by angle-resolved photoemission. Our results show that photoelectron coherence is limited by the crystal corrugation. However, by combining surface morphology measurements of the graphene roughness with angle-resolved photoemission, energy-dependent quasiparticle lifetime and band-structure measurements can be extracted. Our measurements rely on our development of an analytical formulation for relating the crystal corrugation to the photoemission linewidth. Our angle-resolved photoemission spectroscopy measurements show that, despite significant deviation from planarity of the crystal, the electronic structure of exfoliated suspended graphene is nearly that of ideal, undoped graphene; we measure the Dirac point to be within 25 meV of EF. Further, we show that suspended graphene behaves as a marginal Fermi liquid, with a quasiparticle lifetime that scales as (E-EF)-1; comparison with other graphene and graphite data is discussed.

Knox, Kevin R.; Locatelli, Andrea; Yilmaz, Mehmet B.; Cvetko, Dean; Mente?, Tevfik Onur; Nio, Miguel ngel; Kim, Philip; Morgante, Alberto; Osgood, Richard M., Jr.

2011-09-01

298

Determination of corrugation and friction of Cu(111) toward adsorption and motion of Ne and Xe  

NASA Astrophysics Data System (ADS)

The corrugation feature of potential energy surfaces (PESs) for rare-gas (RG) adlayers on metal surfaces has been extensively explored in the positive adsorption energy part. Here, we show that opposite corrugation features may also happen in the negative adsorption energy side for Ne and Xe on Cu(111). While the PES of Ne/Cu(111) is corrugated near the equilibrium adsorption geometry, i.e., Ne prefers the hollow site, the PES of Xe/Cu(111) is anticorrugated, i.e., Xe prefers the atop site. The weak hybridization of RG p and Cu d states is critical for this qualitative difference. Furthermore, the calculated activation energies indicate that Ne may move on Cu(111) at a very low temperature, whereas Xe motion can be activated only above 35 K. We found that the inclusion of the nonlocal van der Waals correction is essential for the correct determination of adsorption and motion energetics for RG adatoms on metals through density functional calculations.

Zhang, Y. N.; Bortolani, V.; Mistura, G.

2014-04-01

299

Effect of discrete track support by sleepers on rail corrugation at a curved track  

NASA Astrophysics Data System (ADS)

The paper investigates into the effect of discrete track support by sleepers on the initiation and development of rail corrugation at a curved track when a railway vehicle passes through using a numerical method. The numerical method considers a combination of Kalker's rolling contact theory with non-Hertzian form, a linear frictional work model and a dynamics model of a half railway vehicle coupled with the curved track. The half-vehicle has a two-axle bogie and doubled suspension systems. It is treated as a full dynamic rigid multi-body model. In the track model, an Euler beam is used to model the rail, and the discrete track support by sleepers moving backward with respect to the vehicle running direction is considered to simulate the effect of the discrete sleeper support on the wheels/rails in rolling contact when the vehicle moves on the track. The sleeper is treated as a rigid body and the ballast bed is replaced with equivalent mass bodies. The numerical analysis exams in detail the variations of wheel/rail normal loads, the creepages, and the rail wear volume along the curved track. Their variations are much concerned with the discrete track support. The numerical results show that the discrete track support causes the fluctuating of the normal loads and creepages at a few frequencies. These frequencies comprise the passing frequency of the sleepers and the excited track resonant frequencies, which are higher than the sleeper passing frequency. Consequently, rail corrugation with several wavelengths initiates and develops. Also the results show that the contact vibrating between the curved rails and the four wheels of the same bogie has different frequencies. In this way, the different key frequencies to be excited play an important role in the initiation and development of curved rail corrugation. Therefore, the corrugations caused by the four wheels of the same bogie present different wavelengths. The paper shows and discusses the depths of the initial corrugations caused by the four wheels of the same bogie, at the entering transition curve, the circle curve and the exit transition curve of the curved track, respectively.

Jin, X. S.; Wen, Z. F.

2008-08-01

300

Heat Pipe Systems  

NASA Technical Reports Server (NTRS)

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.

1988-01-01

301

Guidable pipe plug  

DOEpatents

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.

Glassell, Richard L. (Knoxville, TN); Babcock, Scott M. (Farragut, TN); Lewis, Benjamin E. (Farragut, TN)

2001-01-01

302

Pipe inspection using the pipe crawler. Innovative technology summary report  

SciTech Connect

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.

NONE

1999-05-01

303

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

NASA Astrophysics Data System (ADS)

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.

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

2014-11-01

304

Experimenting with a ``Pipe'' Whistle  

NASA Astrophysics Data System (ADS)

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.

Stafford, Olga

2012-04-01

305

Jamaican red clay tobacco pipes  

E-print Network

of Department) December 1992 ABSTRACT Jamaican Red Clay Tobacco Pipes. (December 1992) Kenan Paul Heidtke, B. A. , Texas Lutheran College Chair of Advisory Committee: Dr. D. L. Hamilton This thesis is a study of the red clay tobacco pipes which are found... with a special emphasis on pipes recovered from the important English colonial city of Port Royal. Until it was almost totally destroyed by an earthquake in 1692, Port Royal was the most important English city in the Caribbean. The goals...

Heidtke, Kenan Paul

2012-06-07

306

Multileg Heat-Pipe Evaporator  

NASA Technical Reports Server (NTRS)

Parallel pipes provide high heat flow from small heat exchanger. Six parallel heat pipes extract heat from overlying heat exchanger, forming evaporator. Vapor channel in pipe contains wick that extends into screen tube in liquid channel. Rods in each channel hold wick and screen tube in place. Evaporator compact rather than extended and more compatible with existing heat-exchanger geometries. Prototype six-pipe evaporator only 0.3 m wide and 0.71 m long. With ammonia as working fluid, transports heat to finned condenser at rate of 1,200 W.

Alario, J. P.; Haslett, R. A.

1986-01-01

307

Thermostructural applications of heat pipes  

NASA Technical Reports Server (NTRS)

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.

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

1979-01-01

308

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

DOEpatents

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.

Fischer, William H. (Pittsburgh, PA)

1984-01-01

309

Experimental studies of magnetically scannable leaky-wave antennas having a corrugated ferrite slab/dielectric layer structure  

NASA Astrophysics Data System (ADS)

The radiation characteristics of a magnetically scannable leaky-wave antenna using a corrugated ferrite slab supported by a Teflon waveguide have been demonstrated experimentally. A corrugated polycrystalline yttrium iron garnet (YIG) slab having the dimensions 150.0 mm x 15.0 mm x 10 mm has been fabricated. The corrugation depth, corrugation spacing, and number of corrugations are 150.0 microns, 2.0 mm, and 55.0, respectively. Experiments have been carried out in the millimeter-wave frequency range from 40.0 to 50.0 GHz. The main beam direction of the leaky wave shifts continuously about 41.0 deg at the operating frequency 46.8 GHz by altering the dc magnetic field up to 1.4 T. It is found that the corresponding half-power beamwidth varies from 3.2 deg to 3.6 deg and a maximum scanning rate is 1.0 deg/0.02 T. Experimental results are compared with theory based on the dispersion relation of the ferrite slab/dielectric layer structure.

Maheri, Heshmatollah; Tsutsumi, Makoto; Kumagai, Nobuaki

1988-07-01

310

Non-contact gears: I. Next-to-leading order contribution to lateral Casimir force between corrugated parallel plates  

E-print Network

We calculate the lateral Casimir force between corrugated parallel plates, described by $\\delta$-function potentials, interacting through a scalar field, using the multiple scattering formalism. The contributions to the Casimir energy due to uncorrugated parallel plates is treated as a background from the outset. We derive the leading- and next-to-leading-order contribution to the lateral Casimir force for the case when the corrugation amplitudes are small in comparison to corrugation wavelengths. We present explicit results in terms of finite integrals for the case of the Dirichlet limit, and exact results for the weak-coupling limit, for the leading- and next-to-leading-orders. The correction due to the next-to-leading contribution is significant. In the weak coupling limit we calculate the lateral Casimir force exactly in terms of a single integral which we evaluate numerically. Exact results for the case of the weak limit allows us to estimate the error in the perturbative results. We show that the error in the lateral Casimir force, in the weak coupling limit, when the next-to-leading order contribution is included is remarkably low when the corrugation amplitudes are small in comparison to corrugation wavelengths. We expect similar conclusions to hold for the Dirichlet case. The analogous calculation for the electromagnetic case should reduce the theoretical error sufficiently for comparison with the experiments.

Ines Cavero-Pelaez; Kimball A. Milton; Prachi Parashar; K. V. Shajesh

2008-05-19

311

Prediction of heat transfer coefficients and friction factors for evaporation of R-134a flowing inside corrugated tubes  

NASA Astrophysics Data System (ADS)

In this study, experimental and simulation studies of the evaporation heat transfer coefficient and pressure drop of R-134a flowing through corrugated tubes are conducted. The test section is a horizontal counter-flow concentric tube-in-tube heat exchanger 2.0 m in length. A smooth tube and corrugated tubes with inner diameters of 8.7 mm are used as the inner tube. The outer tube is made from a smooth copper tube with an inner diameter of 21.2 mm. The corrugation pitches used in this study are 5.08, 6.35, and 8.46 mm. Similarly, the corrugation depths are 1, 1.25, and 1.5 mm, respectively. The results show that the maximum heat transfer coefficient and pressure drop obtained from the corrugated tube are up to 22 and 19 % higher than those obtained from the smooth tube, respectively. In addition, the average difference of the heat transfer coefficient and pressure drop between the simulation model and experimental data are about 10 and 15 %, respectively.

Laohalertdecha, S.; Aroonrat, K.; Dalkilic, A. S.; Mahian, O.; Kaewnai, S.; Wongwises, S.

2014-04-01

312

Large-bore pipe decontamination  

SciTech Connect

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.

Ebadian, M.A.

1998-01-01

313

49 CFR 236.712 - Brake pipe.  

Code of Federal Regulations, 2010 CFR

... 2010-10-01 false Brake pipe. 236.712 Section 236.712...INSTRUCTIONS GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL...Definitions 236.712 Brake pipe. A pipe running from the engineman's...

2010-10-01

314

14 CFR 29.1123 - Exhaust piping.  

Code of Federal Regulations, 2011 CFR

...Exhaust System 29.1123 Exhaust piping. (a) Exhaust piping must be heat and corrosion resistant, and must have provisions to prevent failure due to expansion by operating temperatures. (b) Exhaust piping must be supported to...

2011-01-01

315

14 CFR 29.1123 - Exhaust piping.  

Code of Federal Regulations, 2010 CFR

...Exhaust System 29.1123 Exhaust piping. (a) Exhaust piping must be heat and corrosion resistant, and must have provisions to prevent failure due to expansion by operating temperatures. (b) Exhaust piping must be supported to...

2010-01-01

316

14 CFR 27.1123 - Exhaust piping.  

Code of Federal Regulations, 2011 CFR

...Exhaust System 27.1123 Exhaust piping. (a) Exhaust piping must be heat and corrosion resistant, and must have provisions to prevent failure due to expansion by operating temperatures. (b) Exhaust piping must be supported to...

2011-01-01

317

14 CFR 27.1123 - Exhaust piping.  

Code of Federal Regulations, 2010 CFR

...Exhaust System 27.1123 Exhaust piping. (a) Exhaust piping must be heat and corrosion resistant, and must have provisions to prevent failure due to expansion by operating temperatures. (b) Exhaust piping must be supported to...

2010-01-01

318

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

NASA Technical Reports Server (NTRS)

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.

Wincheski, Buzz; Simpson, John; Hall, George

2008-01-01

319

High performance WR-1.5 corrugated horn based on stacked rings  

E-print Network

We present the development and characterisation of a high frequency (500-750 GHz) corrugated horn based on stacked rings. A previous horn design, based on a Winston profile, has been adapted for the purpose of this manufacturing process without noticeable RF degradation. A subset of experimental results obtained using a vector network analyser are presented and compared to the predicted performance. These first results demonstrate that this technology is suitable for most commercial applications and also astronomical receivers in need of horn arrays at high frequencies.

Maffei, Bruno; de Rijk, Emile; Ansermet, Jean-Philippe; Pisano, Giampaolo; Legg, Stephen; Macor, Alessandro

2014-01-01

320

High performance WR-1.5 corrugated horn based on stacked rings  

NASA Astrophysics Data System (ADS)

We present the development and characterisation of a high frequency (500 - 750 GHz) corrugated horn based on stacked rings. A previous horn design, based on a Winston profile, has been adapted for the purpose of this manufacturing process without noticeable RF degradation. A subset of experimental results obtained using a vector network analyser are presented and compared to the predicted performance. These first results demonstrate that this technology is suitable for most commercial applications and also astronomical receivers in need of horn arrays at high frequencies.

Maffei, Bruno; von Bieren, Arndt; de Rijk, Emile; Ansermet, Jean-Philippe; Pisano, Giampaolo; Legg, Stephen; Macor, Alessandro

2014-07-01

321

Pneumatic Pressure Cell with Twin Diaphragms Embedding Spherical Corrugations in a Dual Diaphragm Structure  

E-print Network

Thin metallic shallow spherical diaphragms are being used for measuring pneumatic pressure in process industries. The drift in vertex realized due to application of pressure is transformed into electrical signal and this is calibrated for pressure. We now propose a modified structure for the pressure cell by having double ended shallow spherical shells embedded with spherical corrugations as to enhance the sensitivity to a greater extent. By having dual such installation in the structure of the pressure cell it concedes further increase in sensitivity. The construction details of the diaphragm structure, theory and analysis to assess the performance are presented.

Cellatoglu, A

2012-01-01

322

3D finite element modeling of the micromachined microphone with corrugated diaphragm  

NASA Astrophysics Data System (ADS)

Measurements of acoustic pressure oscillations on curvilinear surface streamlined by a flow, for example, on the wall of wind-tunnel or airfoil is necessary to supply for aeroacoustic appendices. Microphone should have the minimal sizes and feeler set flush-mounted. Such microphones are demanded for creation distributed audio-systems and noise reduction devices in the source. Developed the MEMS-microphone with corrugated diaphragm should have a sharp response, stability to effects of ram airflow and high level pressure. Preliminary simulation of design and technological parameters is necessary for creation of this microphone.

Borovkov, Alexei I.; Pyatishev, Evgenij N.; Lurie, Mihail S.; Korshunov, Andrey V.; Akulshin, Y. D.; Sabadash, V. O.; Smolnikov, B. A.

2001-02-01

323

3D finite element modeling of the micromachined microphone with corrugated diaphragm  

NASA Astrophysics Data System (ADS)

Measurements of acoustic pressure oscillations on curvilinear surface streamlined by a flow, for example, on the wall of wind-tunnel or airfoil is necessary to supply for aeroacoustic appendices. Microphone should have the minimal sizes and feeler set flush-mounted. Such microphones are demanded for creation distributed audio-systems and noise reduction devices in the source. Developed the MEMS-microphone with corrugated diaphragm should have a sharp response, stability to effects of ram airflow and high level pressure. Preliminary simulation of design and technological parameters is necessary for creation of this microphone.

Borovkov, Alexei I.; Pyatishev, Evgenij N.; Lurie, Mihail S.; Korshunov, Andrey V.; Akulshin, Y. D.; Sabadash, V. O.; Smolnikov, B. A.

2000-02-01

324

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

SciTech Connect

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.

Wincheski, Buzz [NASA Langley Research Center, Hampton, VA 23681 (United States); Simpson, John [Lockheed Martin Space Operations, Hampton, VA 23681 (United States); Hall, George [George Washington University, Washington, D.C. 20052 (United States)

2009-03-03

325

Resonant transmission of acoustic waves through an elastic plate quasiperiodically corrugated on surfaces  

NASA Astrophysics Data System (ADS)

In this work, we study the resonant transmission of acoustic waves through a plate with quasiperiodic surface corrugations. The transmission spectrum shows peculiar transmission peaks, which cannot be simply attributed to the coherent diffraction as recognized previously in structured hard plates (without sustaining internal modes), whereas come from the resonant excitation of the coupled Stoneley surface modes in the elastic plate. The excitation frequencies can be determined by the geometrical structure factor of the quasiperiodic lattice, combining with the dispersion relation of the surface modes.

Hao, Rui; Qiu, Chunyin; Hu, Yanyun; Tang, Kun; Liu, Zhengyou

2011-10-01

326

Effects of asymmetric surface corrugations on fully metal-coated scanning near field optical microscopy tips.  

PubMed

We propose a new configuration for a fully metal coated scanning near field (SNOM) probe based on asymmetric corrugations in the metal coating. The variation in the metal surface induces coupling mechanisms leading to the creation of a localized hot spot under linearly polarized excitation. Field localization is an effect of paramount importance for resolution but cannot be achieved with standard axisymmetric fully metal-coated probes, unless a more cumbersome radially polarized excitation is used. Our simulations show that this promising structure allows one to simplify the mode injection procedures circumventing the need for a radially polarized beam. PMID:20588716

Lotito, Valeria; Sennhauser, Urs; Hafner, Christian

2010-04-12

327

Single polymer adsorption in shear: flattening versus hydrodynamic lift and corrugation effects  

E-print Network

The adsorption of a single polymer to a flat surface in shear is investigated using Brownian hydrodynamics simulations and scaling arguments. Competing effects are disentangled: in the absence of hydrodynamic interactions, shear drag flattens the chain and thus enhances adsorption. Hydrodynamic lift on the other hand gives rise to long-ranged repulsion from the surface which preempts the surface-adsorbed state via a discontinuous desorption transition, in agreement with theoretical arguments. Chain flattening is dominated by hydrodynamic lift, so overall, shear flow weakens the adsorption of flexible polymers. Surface friction due to small-wavelength surface potential corrugations is argued to weaken the surface attraction as well.

Andreas Serr; Christian Sendner; Florian Mueller; Thomas R. Einert; Roland R. Netz

2010-10-25

328

Terahertz surface plasmon polariton propagation and focusing on periodically corrugated metal wires  

E-print Network

In this letter we show how the dispersion relation of surface plasmon polaritons (SPPs) propagating along a perfectly conducting wire can be tailored by corrugating its surface with a periodic array of radial grooves. In this way, highly localized SPPs can be sustained in the terahertz region of the electromagnetic spectrum. Importantly, the propagation characteristics of these spoof SPPs can be controlled by the surface geometry, opening the way to important applications such as energy concentration on cylindrical wires and superfocusing using conical structures.

Maier, S A; Garca-Vidal, F J; Martn-Moreno, L; Andrews, Steve R.; Maier, Stefan A.

2006-01-01

329

Distributed-feedback terahertz quantum-cascade lasers with laterally corrugated metal waveguides  

NASA Astrophysics Data System (ADS)

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.

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

2005-11-01

330

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

NASA Technical Reports Server (NTRS)

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.

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

2005-01-01

331

Characterization and Modeling of Laser Micromachined Periodically Corrugated Metallic Terahertz Wire Waveguides  

NASA Astrophysics Data System (ADS)

Finite element method simulations of periodically corrugated metal terahertz wire waveguides have been conducted with concurrent analysis done on both the near-field confinement properties and the far-field emission properties at the end of the waveguides. This modeling was used to guide the choice of design parameters for the fabrication of waveguides with laser micromachining. The waveguides were characterized with a fiber-coupled terahertz time-domain spectroscopy and imaging system. The propagation properties as well as the frequency dependent diffraction at the end of the wire waveguides were examined and compared to straight, non-engineered metallic wire waveguides.

Ganti, Satya; Gault, Zachary; Smith, Stanley; Deibel, Jason A.; Kemp, Izaac; Schroeder, Nicholas; Druffner, Carl

2012-11-01

332

Unsteady mixed convective flow and heat transfer in a vertical corrugated channel with composite porous media  

NASA Astrophysics Data System (ADS)

An unsteady mixed convective flow and heat transfer in a vertical corrugated channel containing porous and fluid layers are considered. The equations of momentum and energy are solved under appropriate boundary and interface conditions with the assumption that the solution consists of a mean part and a perturbed one. The exact solutions are obtained in the long-wave approximation. Separate solutions are matched at the interface with the use of suitable matching conditions. The effects of pertinent parameters, such as the Grashof number, viscosity ratio, width ratio, conductivity ratio, frequency, and the wave parameter on the flow field and heat transfer characteristics are studied.

Umavathi, J. C.; Shekar, M.

2013-07-01

333

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

NASA Technical Reports Server (NTRS)

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.

Newell, Joseph S; Reissner, Eric

1941-01-01

334

Vapor spill pipe monitor  

DOEpatents

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.

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

1983-06-23

335

Pipe crawler with stabilizing midsection  

SciTech Connect

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.

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

1993-09-20

336

Alternate high capacity heat pipe  

NASA Technical Reports Server (NTRS)

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.

Voss, F. E.

1986-01-01

337

Water flows from slotted pipes  

SciTech Connect

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

Olson, D.A.

1981-04-01

338

Pipe crawler with stabilizing midsection  

DOEpatents

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.

Zollinger, William T. (Martinez, GA); Treanor, Richard C. (Augusta, GA)

1994-01-01

339

Pipe crawler with stabilizing midsection  

DOEpatents

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.

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

1994-12-27

340

Effects of metallic absorption and the corrugated layer on the optical extraction efficiency of organic light-emitting diodes  

E-print Network

The absorption of a metallic cathode in OLEDs is analyzed by using FDTD calculation. As the light propagates parallel to the layer, the intensity of Ez polarization decreases rapidly. The intensity at 2.0 um from the dipole is less than a quarter of that at 0.5 um. The strong absorption by a cathode can be a critical factor when considering the increase of optical extraction by means of bending the optical layers. The calculation indicates that the corrugation of layers helps the guided light escape the guiding layer, but also increases the absorption into a metallic cathode. The final optical output power of the corrugated OLED can be smaller than that of the flat OLED. On the contrary, the corrugated structure with a non-absorptive cathode increases the optical extraction by nearly two times.

Lee, Baek-Woon

2011-01-01

341

Prometheus Hot Leg Piping Concept  

NASA Astrophysics Data System (ADS)

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.

Gribik, Anastasia M.; DiLorenzo, Peter A.

2007-01-01

342

Flexible ultrasonic pipe inspection apparatus  

DOEpatents

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.

Jenkins, Charles F. (Aiken, SC); Howard, Boyd D. (Augusta, GA)

1998-01-01

343

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

NASA Astrophysics Data System (ADS)

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.

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

2014-02-01

344

Adhesive contact between a graphene sheet and a nano-scale corrugated surface  

NASA Astrophysics Data System (ADS)

Adhesive contacts between graphene sheets and corrugated surfaces are investigated. It is found that the final configuration between the graphene sheet and the substrate depends not only on the surface roughness of the substrate, but also on the length of graphene. A continuous transition, rather than a recent observation of snap-through transition, is exhibited in our study. For a graphene sheet with a fixed length, it is easy to fully conform to the substrate of small roughness. Otherwise, the graphene sheet will remain flat on top of the corrugated substrate due to the unsatisfied bending energy or partially conform to the substrate due to the resistance of large interface friction. In order to reduce the effect of interface friction on the adhesive configuration, a new method, i.e. tilting the graphene sheet with a proper angle, is proposed. The tilting angle will significantly influence the final conformation of the adhesive interface. Some interesting types of behaviour are observed, such as rolling graphene, a double layer of graphene and fully adhesive contact, which is physically determined by the competition of thermal fluctuation and interfacial van der Waals interaction.

Chen, Hao; Yao, Yin; Chen, Shaohua

2013-05-01

345

Solution of Helmholtz's equation in multilayered dielectric waveguide with periodic surface corrugation  

NASA Astrophysics Data System (ADS)

Dielectric waveguide with periodic surface corrugation are used in distributed feedback lasers and DBR lasers. In this paper the boundary element method (BEM) has been used to analyze 2D dielectric periodic corrugated waveguides. It is a very efficient method for analysis of this type of structure. The computational method relies on the numerical solution of the integral wave equation inside the grating region. This formalism has distinct advantages over the more traditional ones, especially when the boundary conditions are imposed through a collocation (point-matching) technique. The unknown field quantities together with all the boundary conditions of the problem are explicitly incorporated in the defining equation. For the problem at hand, the boundary conditions on the longitudinal interfaces of the grating layer are functionally known because of the Floquet expansion of the fields in the uniform layers above and below it. On the other hand, the boundary conditions for the interface between the periodic unit cells are naturally provided by Floquet's theorem and continuity requirements. Thus the method can be applied in a rather straightforward way towards a rigorous solution of the periodic problem, without any a priori assumptions, within a user specified accuracy. The BEM is a natural choice for this problem because we seek the field solution only on the grating layer interfaces in order to set up a transverse resonant-type characteristic equation for propagating mode. In this paper electromagnetic field and coupling coefficient for multi- layer dielectric waveguide is calculated.

Mossallaei, Hossein; Abiri, Habibollah; Rahnavard, Mohammad H.; Zomorrodi, Mehrdad

1999-05-01

346

Rectified brownian transport in corrugated channels: Fractional brownian motion and Le?vy flights.  

PubMed

We study fractional brownian motion and Le?vy flights in periodic corrugated channels without any external driving forces. From numerical simulations, we find that both fractional gaussian noise and Le?vy-stable noise in asymmetric corrugated channels can break thermodynamical equilibrium and induce directed transport. The rectified mechanisms for fractional brownian motion and Le?vy flights are different. The former is caused by non-uniform spectral distribution (low or high frequencies) of fractional gaussian noise, while the latter is due to the nonthermal character (occasional long jumps) of the Le?vy-stable noise. For fractional brownian motion, average velocity increases with the Hurst exponent for the persistent case, while for the antipersistent case there exists an optimal value of Hurst exponent at which average velocity takes its maximal value. For Le?vy flights, the group velocity decreases monotonically as the Le?vy index increases. In addition, for both cases, the optimized periodicity and radius at the bottleneck can facilitate the directed transport. Our results could be implemented in constrained structures with narrow channels and pores where the particles undergo anomalous diffusion. PMID:23145711

Ai, Bao-quan; Shao, Zhi-gang; Zhong, Wei-rong

2012-11-01

347

Light pipe - design for efficiency  

SciTech Connect

The high cost and availability of materials which are clear enough to transmit light without absorption has limited the idea of piping large-scale quantities of light. The light pipe uses the principle of Total Internal Reflection, with the light guided by very accurate prisms. The transmission of light directed into the end of a Light Pipe at an angle of less than 27.6 degrees is theoretically 100% efficient. The author describes its uses and advantages for lighting offices, cold storage areas, difficult access and hazardous areas, and for solar lighting. Future directions will be to improve the economics and accuracy of the technology. 4 references, 2 figures.

Hockey, S.N.

1985-08-01

348

Equations shorten pipe collapse calculations  

SciTech Connect

The API suggests collapse pressure equations for long, perfectly round, steel oil field casing, tubing, drill pipe, and line pipe. Operating and service company engineers can substitute two pipe collapse pressure equations for the 12 API equations now in general use. The shorthand results are almost the same as those from the API equations. The shorthand method has the additional advantage of allowing units from any measurement system. The API equations restrict calculations to US units only. The equation box lists the API (Equations 1--12) and the shorthand (Equations 13--14) equations. The API equations are based on work started shortly after the turn of the century.

Avakov, V.A. [Halliburton Energy Services, Duncan, OK (United States)

1995-04-10

349

Heat pipe transient response approximation.  

SciTech Connect

A simple and concise routine that approximates the response of an alkali metal heat pipe to changes in evaporator heat transfer rate is described. This analytically based routine is compared with data from a cylindrical heat pipe with a crescent-annular wick that undergoes gradual (quasi-steady) transitions through the viscous and condenser boundary heat transfer limits. The sonic heat transfer limit can also be incorporated into this routine for heat pipes with more closely coupled condensers. The advantages and obvious limitations of this approach are discussed. For reference, a source code listing for the approximation appears at the end of this paper.

Reid, R. S. (Robert Stowers)

2001-01-01

350

Variable conductance heat pipe technology  

NASA Technical Reports Server (NTRS)

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.

Marcus, B. D.; Edwards, D. K.; Anderson, W. T.

1973-01-01

351

A Heat Pipe Rankine engine  

NASA Astrophysics Data System (ADS)

The Heat Pipe Rankine (HPR) engine is a new concept for small scale power generation that uses heat and mass transport features of a heat pipe. A heat pipe is a heat transfer device in which heat is transferred efficiently from the evaporator section to the condenser section. Mechanical work is produced by a turbine placed in the vapor flowing between the evaporator and the condenser sections. As an external combustion engine, the HPR engine can utilize energy sources at various temperature levels and be adapted to different applications.

Chuah, Y. K.; Kreith, F.

1985-12-01

352

Decontaminating Aluminum/Ammonia Heat Pipes  

NASA Technical Reports Server (NTRS)

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.

Jones, J. A.

1985-01-01

353

Page 1 of 1 Pipe School  

E-print Network

­ Rigid and Flexible Pipes: A comparison of rigid (concrete, clay, etc.) and flexible (steel, HDPE, PVC own) 1:00 PM Design and Construction Considerations for PVC Pipe: Everything you need to know about PVC pipe and its applications. John Houle, P.E., Uni-Bell PVC Pipe Association 1:45 Design

Huang, Haiying

354

Hg supply piping simulation Stony Brook University  

E-print Network

Hg supply piping simulation (No MHD) Stony Brook University Yan Zhan Prof. Foluso Ladeinde July 2nd, 2010 #12;Outline · Hg supply piping in Muon Collider · Turbulence models for bend pipe flow · Problems need studying · Arrangements in the near future #12;Outline · Hg supply piping in Muon Collider ­ Hg

McDonald, Kirk

355

Heat pipe technology: A biblography with abstracts  

NASA Technical Reports Server (NTRS)

A bibliography of heat pipe research and development projects conducted during April through June 1972, is presented. The subjects discussed are: (1) general information, (2) heat pipe applications, (3) heat pipe theory, (4) design and fabrication, (5) test and operation, (6) subject and author index, and (7) heat pipe related patents.

1972-01-01

356

Heat pipes and their technical applications  

Microsoft Academic Search

A general review paper on heat pipes is presented with attention given to principles of operation. Also considered are transfer processes in heat-pipe wicks, the effect of the structural characteristics of a wick on convective transfer of the working fluid, and heat and mass transfer in the wicks of low-temperature heat pipes. Applications of heat pipes in such fields as

L. L. Vasilev

1976-01-01

357

Heat pipe life and processing study  

NASA Technical Reports Server (NTRS)

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.

Antoniuk, D.; Luedke, E. E.

1979-01-01

358

Nitrogen heat pipe for cryocooler thermal shunt  

SciTech Connect

A nitrogen heat pipe was designed, built and tested for the purpose of providing a thermal shunt between the two stages of a Gifford-McMahan (GM) cryocooler during cooldown. The nitrogen heat pipe has an operating temperature range between 63 and 123 K. While the heat pipe is in the temperature range during the system cooldown, it acts as a thermal shunt between the first and second stage of the cryocooler. The heat pipe increases the heat transfer to the first stage of the cryocooler, thereby reducing the cooldown time of the system. When the heat pipe temperature drops below the triple point, the nitrogen working fluid freezes, effectively stopping the heat pipe operation. A small heat leak between cryocooler stages remains because of axial conduction along the heat pipe wall. As long as the heat pipe remains below 63 K, the heat pipe remains inactive. Heat pipe performance limits were measured and the optimum fluid charge was determined.

Prenger, F.C.; Hill, D.D.; Daney, D.E.; Daugherty, M.A. [Los Alamos National Lab., NM (United States); Green, G.F.; Roth, E.W. [Naval Surface Warfare Center, Annapolis, MD (United States)

1995-09-01

359

Axial forces in piping systems  

SciTech Connect

This paper reviews the various pipe Code requirements related to control of axial forces in above ground piping systems. With the exception of ASME Section III (for seismic anchor motions) the Codes do not have specific limits for stresses induced by axial forces (F/A). These new limits will require changes to existing piping analysis computer programs. The present Code explicit limits on stresses due to bending moments result in implicit limits on axial stresses and associated axial forces. It is shown that the limitations of stresses in piping components due to bending moments result in corresponding conservative limits in stresses due to axial forces. Hence limits on axial forces are not required.

Wais, E.A. [Wais and Associates, Inc., Norcross, GA (United States)

1996-12-31

360

Heat Pipes: An Industrial Application  

E-print Network

This paper reviews the basics of heat pipe exchangers. Included are how they are constructed, how they operate, where they have application, and various aspects of evaluating a potential application. After discussing the technical aspects of heat...

Murray, F.

1984-01-01

361

Experimental Demonstration of Mode Change in a Q-Band Oversized Backward Wave Oscillator due to Corrugation Number  

NASA Astrophysics Data System (ADS)

Operation mode of an oversized backward wave oscillator is studied experimentally, using an oversized slow-wave structure. The dispersion characteristics of the slow-wave structure are determined by the average radius, corrugation amplitude and pitch length of the periodic waveguide. The corrugation amplitude and the corrugation period mainly determine the upper cutoff frequency of the lowest mode. The lower cutoff frequency is determined by the average radius. In this work, a Q-band periodic slow-wave structure is fabricated from aluminum. The diameter of the slow-wave structure is about 4 times free space wavelength. The beam voltage is weakly relativistic, around 50 kV, and the beam current is in the range of 100 A. The output powers of several 10 kW are obtained in the Q-band, i.e., the estimated frequency is in the range of 34-41 GH. The output modes are examined by measuring the radiation patterns. Nonaxisymmetric as well as axisymmetric modes are observed. It is demonstrated for the first time that the nonaxisymmetric and axisymmetric operations of the oversized BWO can be controlled by changing the corrugation number of slow-wave structure.

Ogura, Kazuo; Yoshida, Ryo; Komiyama, Kiyofumi; Sakai, Masakazu; Yamazaki, Hoshiyuki

362

ARTICLES: Corrugated focusing gratings for coupling radiation in and out of diffused LiNbO3 waveguides  

Microsoft Academic Search

A fabrication method is described and the results are given of an investigation of corrugated periodic and focusing gratings on the surfaces of diffused waveguides in LiNbO3. The paraxial approximation is used to obtain analytic expressions for the optical parameters of a system employed to form focusing gratings designed to ensure the minimum dimensions of a focusing spot. In an

Yurii V. Gulyaev; Yu M. Dikaev; Yu L. Kopylov; I. M. Kotelyanskii; V. B. Kravchenko; E. N. Mirgorodskaya; V. P. Orlov

1983-01-01

363

Two-phase friction pressure drop through corrugated tubes and quick-disconnect attachments in reduced gravity  

E-print Network

A two-phase flow experiment package was used to collect pressure drop data for corrugated flexible tubes and quick-disconnect attachments. Single-phase pressure drop measurements were taken on the ground and two-phase reduced gravity measurements...

Marsden, Kenneth

2012-06-07

364

FE ANALYSIS OF CREEP AND HYGROEXPANSION RESPONSE OF A CORRUGATED FIBERBOARAD TO A MOISTURE FLOW: A TRANSIENT NONLINEAR ANALYSIS  

Microsoft Academic Search

This paper presents a model using finite element method to study the response of a typical commercial corrugated fiberboard due to an induced moisture function at one side of the fiberboard. The model predicts how the moisture diffusion will permeate through the fiberboard's layers (medium and liners) providing information on moisture content at any given point throughout the structure. The

Adeeb A. Rahman; Thomas J. Urbanik; Mustafa Mahamid

365

Intermediate Temperature Water Heat Pipe Tests  

NASA Technical Reports Server (NTRS)

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.

Devarakonda, Angirasa; Xiong, Daxi; Beach, Duane E.

2004-01-01

366

Intermediate Temperature Water Heat Pipe Tests  

NASA Technical Reports Server (NTRS)

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.

Devarakonda, Angirasa; Xiong, Da-Xi; Beach, Duane E.

2005-01-01

367

Heat Pipe Thermal Conditioning Panel  

NASA Technical Reports Server (NTRS)

The technology involved in designing and fabricating a heat pipe thermal conditioning panel to satisfy a broad range of thermal control system requirements on NASA spacecraft is discussed. The design specifications were developed for a 30 by 30 inch heat pipe panel. The fundamental constraint was a maximum of 15 gradient from source to sink at 300 watts input and a flux density of 2 watts per square inch. The results of the performance tests conducted on the panel are analyzed.

Saaski, E. W.

1973-01-01

368

Mapping Temperatures On Heat Pipes  

NASA Technical Reports Server (NTRS)

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.

Gunnerson, Fred S.; Thorncroft, Glen E.

1993-01-01

369

Pipe weld crown removal device  

DOEpatents

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.

Sword, Charles K. (Pleasant Hills, PA); Sette, Primo J. (West Newton, PA)

1992-01-01

370

Heat pipe turbine vane cooling  

SciTech Connect

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.

Langston, L.; Faghri, A. [Connecticut Univ., Storrs, CT (United States). Dept. of Mechanical Engineering

1995-12-31

371

Light Pipe Energy Savings Calculator  

NASA Astrophysics Data System (ADS)

Dependence on fossil fuels is unsustainable and therefore a shift to renewable energy sources such as sunlight is required. Light pipes provide a way to utilize sunlight for interior lighting, and can reduce the need for fossil fuel-generated electrical energy. Because consumers considering light pipe installation may be more strongly motivated by cost considerations than by sustainability arguments, an easy means to examine the corresponding costs and benefits is needed to facilitate informed decision-making. The purpose of this American Physical Society Physics and Society Fellowship project is to create a Web-based calculator to allow users to quantify the possible cost savings for their specific light pipe application. Initial calculations show that the illumination provided by light pipes can replace electric light use during the day, and in many cases can supply greater illumination levels than those typically given by electric lighting. While the installation cost of a light pipe is significantly greater than the avoided cost of electricity over the lifetime of the light pipe at current prices, savings may be realized if electricity prices increase.

Owens, Erin; Behringer, Ernest R.

2009-04-01

372

Heat pipe cooled power magnetics  

NASA Technical Reports Server (NTRS)

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.

Chester, M. S.

1979-01-01

373

Automated internal pipe cutting device  

DOEpatents

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.

Godlewski, William J. (Clifton Park, NY); Haffke, Gary S. (Ballston Spa, NY); Purvis, Dale (Amsterdam, NY); Bashar, Ronald W. (Oakdale, CT); Jones, Stewart D. (Mechanicville, NY); Moretti, Jr., Henry (Cranston, RI); Pimentel, James (Warwick, RI)

2003-01-21

374

Leaks in pipe networks  

USGS Publications Warehouse

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.

Pudar, Ranko S.; Liggett, James A.

1992-01-01

375

Constraints on axion-nucleon coupling constants from measuring the Casimir force between corrugated surfaces  

NASA Astrophysics Data System (ADS)

We obtain stronger laboratory constraints on the coupling constants of axion-like particles to nucleons from measurements of the normal and lateral Casimir forces between sinusoidally corrugated surfaces of a sphere and a plate. For this purpose, the normal and lateral additional forces arising in the experimental configurations due to the two-axion exchange between protons and neutrons are calculated. Our constraints following from measurements of the normal and lateral Casimir forces are stronger than the laboratory constraints reported so far for masses of axion-like particles larger than 11 and 8 eV, respectively. A comparison between various laboratory constraints on the coupling constants of axion-like particles to nucleons obtained from the magnetometer measurements, Etvos- and Cavendish-type experiments, and from the Casimir effect is performed over the wide range of masses of axion-like particles from 10-10 to 20 eV.

Bezerra, V. B.; Klimchitskaya, G. L.; Mostepanenko, V. M.; Romero, C.

2014-09-01

376

Implementation of the CMOS MEMS Condenser Microphone with Corrugated Metal Diaphragm and Silicon Back-Plate  

PubMed Central

This study reports a CMOS-MEMS condenser microphone implemented using the standard thin film stacking of 0.35 ?m UMC CMOS 3.3/5.0 V logic process, and followed by post-CMOS micromachining steps without introducing any special materials. The corrugated diaphragm for the microphone is designed and implemented using the metal layer to reduce the influence of thin film residual stresses. Moreover, a silicon substrate is employed to increase the stiffness of the back-plate. Measurements show the sensitivity of microphone is ?42 3 dBV/Pa at 1 kHz (the reference sound-level is 94 dB) under 6 V pumping voltage, the frequency response is 100 Hz10 kHz, and the S/N ratio >55 dB. It also has low power consumption of less than 200 ?A, and low distortion of less than 1% (referred to 100 dB). PMID:22163953

Huang, Chien-Hsin; Lee, Chien-Hsing; Hsieh, Tsung-Min; Tsao, Li-Chi; Wu, Shaoyi; Liou, Jhyy-Cheng; Wang, Ming-Yi; Chen, Li-Che; Yip, Ming-Chuen; Fang, Weileun

2011-01-01

377

Implementation of the CMOS MEMS condenser microphone with corrugated metal diaphragm and silicon back-plate.  

PubMed

This study reports a CMOS-MEMS condenser microphone implemented using the standard thin film stacking of 0.35 ?m UMC CMOS 3.3/5.0 V logic process, and followed by post-CMOS micromachining steps without introducing any special materials. The corrugated diaphragm for the microphone is designed and implemented using the metal layer to reduce the influence of thin film residual stresses. Moreover, a silicon substrate is employed to increase the stiffness of the back-plate. Measurements show the sensitivity of microphone is -42 3 dBV/Pa at 1 kHz (the reference sound-level is 94 dB) under 6 V pumping voltage, the frequency response is 100 Hz-10 kHz, and the S/N ratio >55 dB. It also has low power consumption of less than 200 ?A, and low distortion of less than 1% (referred to 100 dB). PMID:22163953

Huang, Chien-Hsin; Lee, Chien-Hsing; Hsieh, Tsung-Min; Tsao, Li-Chi; Wu, Shaoyi; Liou, Jhyy-Cheng; Wang, Ming-Yi; Chen, Li-Che; Yip, Ming-Chuen; Fang, Weileun

2011-01-01

378

Modulation of surface plasmon coupling-in by one-dimensional surface corrugation  

NASA Astrophysics Data System (ADS)

Surface plasmon-polaritons have recently attracted renewed interest in the scientific community for their potential in sub-wavelength optics, light generation and non-destructive sensing. Given that they cannot be directly excited by freely propagating light due to their intrinsic binding to the metal surface, the light-plasmon coupling efficiency becomes of crucial importance for the success of any plasmonic device. Here, we present a comprehensive study on the modulation (enhancement or suppression) of such a coupling efficiency by means of one-dimensional surface corrugation. Our approach is based on simple wave interference and enables us to make quantitative predictions which have been experimentally confirmed at both the near-infrared and telecom ranges.

Lpez-Tejeira, F.; Rodrigo, Sergio G.; Martn-Moreno, L.; Garca-Vidal, F. J.; Devaux, E.; Dintinger, J.; Ebbesen, T. W.; Krenn, J. R.; Radko, I. P.; Bozhevolnyi, S. I.; Gonzlez, M. U.; Weeber, J. C.; Dereux, A.

2008-03-01

379

Fabrication of corrugated probes for scanning near-field optical microscopy  

NASA Astrophysics Data System (ADS)

We present a method of fabricating aperture tapered-fiber metal-coated SNOM probes with a corrugated core surface which assures efficient photon-to-plasmon conversion and thus high energy throughput. High energy throughput allows for a small apex aperture and high resolution. The procedure consists of recording of Bragg grating in the to-be-tapered part of a Ge-doped silica fiber and chemical etching with the Turner method. Bragg gratings are recorded with UV light through nearly sinusoidal phase masks of chosen lattice constants. The refractive index contrast in the Bragg grating differentiates the etch rate of the Ge-doped hydrogenated fiber core in exposed and unexposed parts by about 100 nm/min at room temperature.

Wrbel, Piotr; Stefaniuk, Tomasz; Antosiewicz, Tomasz J.; Libura, Adam; Nowak, Grzegorz; Wejrzanowski, Tomasz; Slesinski, Robert; Jedrzejewski, Kazimierz; Szoplik, Tomasz

2011-05-01

380

Radial Corrugations of Multi-Walled Carbon Nanotubes Driven by Inter-Wall Nonbonding Interactions  

PubMed Central

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.

2011-01-01

381

Fabrication of 20 nm half-pitch gratings by corrugation-directed self-assembly  

NASA Astrophysics Data System (ADS)

The evolution of the scaling of modern semiconductor devices is governed by the ability to create scalable high-resolution patterns on substrates. Since it is becoming increasingly difficult and expensive to extend to smaller dimensions using optical lithography, there is a great deal of interest in alternative patterning methods. The self-assembly of block copolymers in thin films, which provides periodic patterns of 10-50 nm length scales, has been recognized as a promising candidate for such patterning. To be practical, however, this approach must provide control over the orientation and lateral placement of the microdomains. We report here our discovery of the controlled alignment of the lamellar microdomains of a block copolymer containing hybrid material using topographic pre-patterns on substrates. We find that this hybrid material forms lamellae with a half-pitch of approximately 20 nm perpendicular to the lines of a surface corrugation.

Kim, Ho-Cheol; Rettner, Charles T.; Sundstrm, Linnea

2008-06-01

382

Constraints on axion-nucleon coupling constants from measuring the Casimir force between corrugated surfaces  

E-print Network

We obtain stronger laboratory constraints on the coupling constants of axion-like particles to nucleons from measurements of the normal and lateral Casimir forces between sinusoidally corrugated surfaces of a sphere and a plate. For this purpose, the normal and lateral additional force arising in the experimental configurations due to two-axion exchange between protons and neutrons are calculated. Our constraints following from measurements of the normal and lateral Casimir forces are stronger than the laboratory constraints reported so far for masses of axion-like particles larger than 11eV and 8eV, respectively. A comparison between various laboratory constraints on the coupling constants of axion-like particles to nucleons obtained from the magnetometer measurements, Eotvos- and Cavendish-type experiments, and from the Casimir effect is performed over the wide range of masses of axion-like particles from 10^{-10}eV to 20eV.

Bezerra, V B; Mostepanenko, V M; Romero, C

2014-01-01

383

Multi-channel composite spoof surface plasmon polaritons propagating along periodically corrugated metallic thin films  

NASA Astrophysics Data System (ADS)

In this work, we demonstrate that composite spoof surface plasmon polaritons can be excited by coplanar waveguide, which are composed of two different spoof surface plasmon polaritons (SSPPs) modes propagating along a periodically corrugated metallic thin film simultaneously. These two SSPPs correspond to the dominant modes of one-dimensional (1D) periodical hole and groove arrays separately. We have designed and simulated a planar composite plasmonic waveguide in the microwave frequencies, and the simulation results show that the composite plasmonic waveguide can achieve multi-channel signal transmission with good propagation performance. The proposed planar composite plasmonic metamaterial can find potential applications in developing surface wave devices in integrated plasmonic circuits and multi-channel signal transmission systems in the microwave and terahertz frequencies.

Liu, Liangliang; Li, Zhuo; Gu, Changqing; Ning, Pingping; Xu, Bingzheng; Niu, Zhenyi; Zhao, Yongjiu

2014-07-01

384

Highly tapered pentagonal bipyramidal Au microcrystals with high index faceted corrugation: Synthesis and optical properties  

PubMed Central

Focusing light at sub-wavelength region opens up interesting applications in optical sensing and imaging beyond the diffraction limit. In the past, tapered Au wires with carved gratings have been employed to achieve nanofocusing. The fabrication process however, is expensive and the obtained wires are polycrystalline with high surface roughness. A chemical synthetic method overcoming these hurdles should be an attractive alternative. Here, we report a method to chemically synthesize Au microcrystals (~10??m) bearing pentagonal bipyramidal morphology with surface corrugations assignable to high index planes. The method is a single step solid state synthesis at a temperature amenable to common substrates. The microcrystals are tapered at both ends forming sharp tips (~55?nm). Individual microcrystals have been used as pick and probe SERS substrates for a dye embedded in a polymer matrix. The unique geometry of the microcrystal also enables light propagation across its length.

Mettela, Gangaiah; Boya, Radha; Singh, Danveer; Kumar, G. V. Pavan; Kulkarni, G. U.

2013-01-01

385

High-efficiency input coupling into optical waveguides using gratings with double-surface corrugation  

NASA Astrophysics Data System (ADS)

Waveguide grating couplers that have surface corrugation on both boundaries of the waveguide were fabricated by the deposition of waveguide material at high-vacuum pressures onto a surface-relief grating etched into the substrate. A lateral shift between the two gratings along the direction of the common grating vector was created during the waveguide deposition when the substrate normal was tilted with respect to the direction of material deposition. A series of waveguide thicknesses having an identical angle of deposition were examined to observe the effect of the waveguide thickness, and corresponding lateral shift, on the branching ratio and input-coupling efficiency. Branching ratios of above 98% and input-coupling efficiencies near the theoretical limit for an incident Gaussian beam were obtained.

Brazas, John C.; McKeon, Amanda L.; Li, Lifeng

1995-02-01

386

Atomic corrugation and electron localization due to Moir patterns in twisted bilayer graphenes  

NASA Astrophysics Data System (ADS)

We report on unprecedentedly large-scale density-functional calculations that clarify atomic and electronic structures of twisted bilayer graphene (BLG). We find the existence of the critical twist angle from either the AB or the AA stacking BLG, above which the two graphene layers are essentially decoupled and below which the atomic planes are corrugated and the Dirac electrons are localized. We also find a magic angle at which the Fermi velocity of the Dirac electron vanishes. We clarify that the Moir pattern in tBLG with a tiny twist angle generates inhomogeneity for the electron systems and thus causes the drastic modification of the electronic properties, leading to flat bands at the Fermi level. Sensitivity to the Moir of the valence-electron density and the electron state near the Fermi level is discussed.

Uchida, Kazuyuki; Furuya, Shinnosuke; Iwata, Jun-Ichi; Oshiyama, Atsushi

2014-10-01

387

Surface Plasmon-Polariton Mediated Red Emission from Organic Light-Emitting Devices Based on Metallic Electrodes Integrated with Dual-Periodic Corrugation  

PubMed Central

We demonstrate an effective approach to realize excitation and outcoupling of the SPP modes associated with both cathode/organic and anode/organic interfaces in OLEDs by integrating dual-periodic corrugation. The dual-periodic corrugation consists of two set gratings with different periods. The light trapped in the SPP modes associated with both top and bottom electrode/organic interfaces are efficiently extracted from the OLEDs by adjusting appropriate periods of two set corrugations, and a 29% enhancement in the current efficiency has been obtained. PMID:25407776

Bi, Yan-Gang; Feng, Jing; Liu, Yu-Shan; Li, Yun-Fei; Chen, Yang; Zhang, Xu-Lin; Han, Xiao-Chi; Sun, Hong-Bo

2014-01-01

388

Magnetic refrigeration apparatus with heat pipes  

DOEpatents

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.

Barclay, J.A.; Prenger, F.C. Jr.

1985-10-25

389

Magnetic refrigeration apparatus with heat pipes  

DOEpatents

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.

Barclay, John A. (Los Alamos, NM); Prenger, Jr., F. Coyne (Madison, WI)

1987-01-01

390

Centrally activated pipe snubbing system  

DOEpatents

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.

Cawley, William E. (Richland, WA)

1985-01-01

391

Pipe crawler with extendable legs  

DOEpatents

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.

Zollinger, William T. (3927 Almon Dr., Martinez, GA 30907)

1992-01-01

392

Pipe crawler with extendable legs  

DOEpatents

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.

Zollinger, W.T.

1992-06-16

393

Flexible ultrasonic pipe inspection apparatus  

DOEpatents

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.

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

1998-06-23

394

46 CFR 153.292 - Separation of piping systems.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Separation of piping systems. 153.292 Section 153...Design and Equipment Piping Systems and Cargo Handling Equipment 153.292 Separation of piping systems. Cargo piping systems...

2010-10-01

395

46 CFR 153.292 - Separation of piping systems.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Separation of piping systems. 153.292 Section 153...Design and Equipment Piping Systems and Cargo Handling Equipment 153.292 Separation of piping systems. Cargo piping systems...

2011-10-01

396

46 CFR 154.512 - Piping: Thermal isolation.  

Code of Federal Regulations, 2010 CFR

...Shipping 5 2010-10-01 2010-10-01 false Piping: Thermal isolation. 154.512 Section 154.512 Shipping ...Cargo and Process Piping Systems 154.512 Piping: Thermal isolation. Low temperature piping must be thermally...

2010-10-01

397

Multiple heat pipe heat exchanger and method for making  

Microsoft Academic Search

A heat pipe heat exchanger has a plurality of heat pipes which are interconnected so as to permit fluid communication between the pipes at least during charging so that the heat pipes may be simultaneously filled with heat transfer fluid.

Maxson

1979-01-01

398

Cryogenic thermal diode heat pipes  

NASA Technical Reports Server (NTRS)

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.

Alario, J.

1979-01-01

399

46 CFR 154.660 - Pipe welding.  

Code of Federal Regulations, 2011 CFR

...of this chapter. (b) Longitudinal butt welds, in piping that does not meet a standard or...56.60-1 of this chapter, and girth butt welds must meet the following: (1) Butt welds of pipes made from carbon, carbon...

2011-10-01

400

46 CFR 154.660 - Pipe welding.  

Code of Federal Regulations, 2012 CFR

...of this chapter. (b) Longitudinal butt welds, in piping that does not meet a standard or...56.60-1 of this chapter, and girth butt welds must meet the following: (1) Butt welds of pipes made from carbon, carbon...

2012-10-01

401

46 CFR 154.660 - Pipe welding.  

Code of Federal Regulations, 2013 CFR

...of this chapter. (b) Longitudinal butt welds, in piping that does not meet a standard or...56.60-1 of this chapter, and girth butt welds must meet the following: (1) Butt welds of pipes made from carbon, carbon...

2013-10-01

402

46 CFR 154.660 - Pipe welding.  

Code of Federal Regulations, 2010 CFR

...of this chapter. (b) Longitudinal butt welds, in piping that does not meet a standard or...56.60-1 of this chapter, and girth butt welds must meet the following: (1) Butt welds of pipes made from carbon, carbon...

2010-10-01

403

14 CFR 29.1123 - Exhaust piping.  

...CATEGORY ROTORCRAFT Powerplant Exhaust System 29.1123 Exhaust piping. (a) Exhaust piping must be heat and corrosion resistant, and must have provisions to prevent failure due to expansion by operating temperatures. (b) Exhaust...

2014-01-01

404

14 CFR 25.1123 - Exhaust piping.  

Code of Federal Regulations, 2011 CFR

...power unit installations, the following apply: (a) Exhaust piping must be heat and corrosion resistant, and must have provisions to prevent failure due to expansion by operating temperatures. (b) Piping must be supported to...

2011-01-01

405

14 CFR 25.1123 - Exhaust piping.  

Code of Federal Regulations, 2010 CFR

...power unit installations, the following apply: (a) Exhaust piping must be heat and corrosion resistant, and must have provisions to prevent failure due to expansion by operating temperatures. (b) Piping must be supported to...

2010-01-01

406

Flat heat pipe design, construction, and analysis  

SciTech Connect

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.

Voegler, G.; Boughey, B.; Cerza, M.; Lindler, K.W.

1999-08-02

407

46 CFR 108.475 - Piping.  

Code of Federal Regulations, 2011 CFR

...and outside from corrosion. (c) Each pipe, valve, and fitting must have support and...extinguishing system must have enough (1) Dirt traps to prevent the accumulation of dirt in its pipes; and (2) Drains to remove liquid...

2011-10-01

408

46 CFR 108.475 - Piping.  

Code of Federal Regulations, 2010 CFR

...and outside from corrosion. (c) Each pipe, valve, and fitting must have support and...extinguishing system must have enough (1) Dirt traps to prevent the accumulation of dirt in its pipes; and (2) Drains to remove liquid...

2010-10-01

409

Heat pipe applications in aircraft propulsion  

NASA Technical Reports Server (NTRS)

Heat pipes for improving the cycle efficiency and/or thrust-to-weight ratio of aircraft gas turbines are examined. A heat pipe employs a capillary structure, a wick, and an evacuated chamber to transfer heat between condensor and evaporator ends. Heat absorbed at the evaporator is transported to the condensor. In an aircraft, the heat pipe can be stationary or rotating, can be used for cooling stators and rotors, and is amenable to shapes such as cylinders, cones, and flat plates. Heat pipes in aircraft gas turbines can be applied for intercooling between stages, regeneration, reheat, and blade cooling. Improvements are projected in the cycle efficiency, thrust and thrust specific fuel consumption in the fanjet by using heat pipes. Consideration is also given to heat pipe heat exchangers with high axial heat transfer for stationary heat pipes and high heat transport for rotating heat pipes.

Beltran, M. R.; Anderson, D. L.; Marto, P. J.

1984-01-01

410

Heat pipe design handbook, part 1  

NASA Technical Reports Server (NTRS)

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.

Skrabek, E. A.

1972-01-01

411

Corrugations and eccentric spirals in Saturn's D ring: New insights into what happened at Saturn in 1983  

E-print Network

Previous investigations of Saturn's outer D ring (73,200-74,000 km from Saturn's center) identified periodic brightness variations whose radial wavenumber increased linearly over time. This pattern was attributed to a vertical corrugation, and its temporal variability implied that some event --possibly an impact with interplanetary debris-- caused the ring to become tilted out the planet's equatorial plane in 1983. This work examines these patterns in greater detail using a more extensive set of Cassini images in order to obtain additional insights into the 1983 event. These additional data reveal that the D ring is not only corrugated, but also contains a time-variable periodic modulation in its optical depth that probably represents organized eccentric motions of the D-ring's particles. This second pattern suggests that whatever event tilted the rings also disturbed the radial or azimuthal velocities of the ring particles. Furthermore, the relative amplitudes of the two patterns indicate that the vertical m...

Hedman, M M; Showalter, M R

2014-01-01

412

Experimental demonstration of longitudinal beam phase space linearizer in a free-electron laser facility by corrugated structures  

E-print Network

Removal of residual linear energy chirp and intrinsic nonlinear energy curvature in the relativistic electron beam from radiofrequency linear accelerator is of paramount importance for efficient lasing of a high-gain free-electron laser. Recently, it was theoretically and experimentally demonstrated that the longitudinal wakefield excited by the electrons itself in the corrugated structure allows for precise control of the electron beam phase space. In this Letter, we report the first utilization of a corrugated structure as beam linearizer in the operation of a seeded free-electron laser driven by a 140 MeV linear accelerator, where a gain of ~10,000 over spontaneous emission was achieved at the second harmonic of the 1047 nm seed laser, and a free-electron laser bandwidth narrowing by about 50% was observed, in good agreement with the theoretical expectations.

Deng, Haixiao; Feng, Chao; Zhang, Tong; Wang, Xingtao; Lan, Taihe; Feng, Lie; Zhang, Wenyan; Liu, Xiaoqing; Yao, Haifeng; Shen, Lei; Li, Bin; Zhang, Junqiang; Li, Xuan; Fang, Wencheng; Wang, Dan; Couprie, Marie-emmanuelle; Lin, Guoqiang; Liu, Bo; Gu, Qiang; Wang, Dong; Zhao, Zhentang

2014-01-01

413

Dynamics of heat-pipe reactors  

NASA Technical Reports Server (NTRS)

A split-core heat pipe reactor, fueled with either U(233)C or U(235)C in a tungsten cermet and cooled by 7-Li-W heat pipes, was examined for the effects of the heat pipes on reactor while trying to safely absorb large reactivity inputs through inherent shutdown mechanisms. Limits on ramp reactivity inputs due to fuel melting temperature and heat pipe wall heat flux were mapped for the reactor in both startup and at-power operating modes.

Niederauer, G. F.

1971-01-01

414

Gray Cast-Iron Water Pipe Metallurgy  

Microsoft Academic Search

Abstract: The results of a,metallographic study of grey,cast iron water pipes are reported. These pipes had been installed between 1885 and 1973 in eight different water systems. Each pipe had been extracted during scheduled maintenance,or failure repairs to provide data for a larger study toproduce,a methodology ,for determining ,the residual life of grey ,cast iron pipes. This metallographic study was

J. M. Rajani

2000-01-01

415

Analysis of Municipal Pipe Network Franchise Institution  

NASA Astrophysics Data System (ADS)

Franchise institution of municipal pipe network has some particularity due to the characteristic of itself. According to the exposition of Chinese municipal pipe network industry franchise institution, the article investigates the necessity of implementing municipal pipe network franchise institution in China, the role of government in the process and so on. And this offers support for the successful implementation of municipal pipe network franchise institution in China.

Yong, Sun; Haichuan, Tian; Feng, Xu; Huixia, Zhou

416

Heat pipe heat exchanger design considerations  

Microsoft Academic Search

Typical heat pipe heat exchangers (HPHX) are described, along with their advantages, uses, and some problems in HPHX design, and a computer HPHX analysis program is discussed with required input data. The computer program is being developed for analysis of heat exchange performance by finned-tube HPHX and thread-puddle-artery heat pipes. Copper-water heat pipes and carbon steel-Dowtherm A heat pipes are

K. T. Feldman; D. C. Lu

1976-01-01

417

A method for implementing a piping inspection  

SciTech Connect

Recent catastrophic piping failures dramatically demonstrate the importance of implementing a piping program. Piping system leaks and ruptures have caused death and injury to plant workers, firefighters, and the public. Significant financial consequences due to unexpected downtime and property damage have plagued industry. The environment has also suffered from the release of toxic chemicals. In the chemical industry, roughly 30% of the catastrophic losses have been historically attributable to piping failures. 1 fig. 1 tab.

Matthews, P.B. [Hartford Steam Boiler and Insurance Co., Hartford, CT (United States)] [Hartford Steam Boiler and Insurance Co., Hartford, CT (United States); Beberman, J.A. [Radian Corp., Tucker, GA (United States)] [Radian Corp., Tucker, GA (United States)

1995-01-01

418

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

DOEpatents

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.

Fischer, William H. (Pittsburgh, PA)

1984-04-24

419

Evanescent light enhancement in a nanometer aperture surrounded by corrugated metal thin film for a terabyte optical disk head  

Microsoft Academic Search

An ultrahigh density optical disk head which utilizes evanescent light (near-field light) had been designed to enhance the near-field optical wave for the throughput increment using the surface plasmon polariton resonance effect between the light inside the near-field optical head and nano-fabricated corrugated metal thin film. The theoretical analysis is discussed with the emphasis on the two- and three-dimensional simulation

Takahito Ono; Yong-Joo Kim

2005-01-01

420

EXPERIMENTAL FLOW VISUALIZATION FOR CORRUGATED AIRFOILS AT LOW REYNOLDS NUMBER INCLUDING DEVELOPMENT OF A PITCH AND PLUNGE FIXTURE  

Microsoft Academic Search

Micro Air Vehicles (MAVs) have small size and extreme maneuverability which makes them ideal for surveillance. Propulsion mechanisms include propellers, rotors, and flapping airfoils. Flapping motions, along with biologically-inspired wing profiles, are of interest due to their use of natural physics. Corrugated airfoil structures appears to have poor aerodynamic performance at higher Reynolds numbers, but serve well at Re<10,000. Understanding

Jeremy Ryan Sparks

2011-01-01

421

Creasing Characteristics of A-Flute Corrugated Fiber Board Using a Rotary Creaser with Respect to Breaking Strength  

Microsoft Academic Search

This paper reports on bending-moment characteristics of heightwise\\/vertical crease of a corrugated fiberboard, a scored line of which is in parallel to the inner flute structure, and the effect of mechanical processing conditions on a failure phenomena of liner sheet scored by a rotary creaser. Regarding the dispersion and the variance of folding resistance, the creaser\\/pre-creaser gaps, the deviation of

Shigeru Nagaswa; Tomohiro Takamatsu; Yasushi Fukuzawa; Yusuke Tozuka

2011-01-01

422

46 CFR 56.10-5 - Pipe.  

Code of Federal Regulations, 2012 CFR

...also 56.60-20.) (1) Copper and brass pipe for water and steam service may...temperatures to 406 F. (2) Copper and brass pipe for air may be used in accordance...pounds per square inch. (5) Copper, brass, or aluminum pipe or tube shall not...

2012-10-01

423

46 CFR 56.10-5 - Pipe.  

Code of Federal Regulations, 2013 CFR

...also 56.60-20.) (1) Copper and brass pipe for water and steam service may...temperatures to 406 F. (2) Copper and brass pipe for air may be used in accordance...pounds per square inch. (5) Copper, brass, or aluminum pipe or tube shall not...

2013-10-01

424

46 CFR 56.10-5 - Pipe.  

Code of Federal Regulations, 2011 CFR

...also 56.60-20.) (1) Copper and brass pipe for water and steam service may...temperatures to 406 F. (2) Copper and brass pipe for air may be used in accordance...pounds per square inch. (5) Copper, brass, or aluminum pipe or tube shall not...

2011-10-01

425

Bag Test Measures Leakage From Insulated Pipe  

NASA Technical Reports Server (NTRS)

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.

Schock, Kent D.; Easter, Barry P.

1994-01-01

426

The locating ways of laying pipe manipulator  

NASA Astrophysics Data System (ADS)

The laying pipe manipulator is a new equipment to lay concrete pipe. This kind of manipulator makes the work of laying pipes mechanized and automated. We report here a new laying pipe manipulator. The manipulator has 5 free degrees, and is driven by the hydraulic system. In the paper, one critical question of manipulator is studied: the locating ways of the manipulator to lay concrete pipe. During the process of laying concrete pipe, how to locate the manipulator is realized by the locating system of manipulator. The locating system consists of photoelectric target, laser producer, and computer. According to different construction condition, one or two or three photoelectric targets can be used. During the process of laying concrete pipe, if the interface of pipes are jointed together, and the other segment of pipe deviates from the pipe way, one target can be used, if the angle that the manipulator rotates around the holding pipe's axes is 0, two targets can be used, three targets can be used at any site. In the paper, according to each locating way, the theory analysis is done. And the mathematical models of the manipulator moving from original position to goal position are obtained by different locating way. And the locating experiment was done. According to the experiment result, the work principle and mathematical models of different locating way was turned out to be well adopted for requirement, the mathematical model of different locating way supplies the basic control theory for the manipulator to lay and joint concrete pipe automatically.

Wang, Dan; Li, Bin; Lei, DongLiang

2010-01-01

427

The locating ways of laying pipe manipulator  

NASA Astrophysics Data System (ADS)

The laying pipe manipulator is a new equipment to lay concrete pipe. This kind of manipulator makes the work of laying pipes mechanized and automated. We report here a new laying pipe manipulator. The manipulator has 5 free degrees, and is driven by the hydraulic system. In the paper, one critical question of manipulator is studied: the locating ways of the manipulator to lay concrete pipe. During the process of laying concrete pipe, how to locate the manipulator is realized by the locating system of manipulator. The locating system consists of photoelectric target, laser producer, and computer. According to different construction condition, one or two or three photoelectric targets can be used. During the process of laying concrete pipe, if the interface of pipes are jointed together, and the other segment of pipe deviates from the pipe way, one target can be used, if the angle that the manipulator rotates around the holding pipe's axes is 0, two targets can be used, three targets can be used at any site. In the paper, according to each locating way, the theory analysis is done. And the mathematical models of the manipulator moving from original position to goal position are obtained by different locating way. And the locating experiment was done. According to the experiment result, the work principle and mathematical models of different locating way was turned out to be well adopted for requirement, the mathematical model of different locating way supplies the basic control theory for the manipulator to lay and joint concrete pipe automatically.

Wang, Dan; Li, Bin; Lei, Dongliang

2009-12-01

428

46 CFR 95.17-15 - Piping.  

Code of Federal Regulations, 2010 CFR

...of this chapter. (b) All piping, valves, and fittings of...the Commandant. (c) All piping, valves, and fittings shall...protected against injury. (d) Drains and dirt traps shall be fitted...of dirt or moisture. (e) Piping shall be used for no other...

2010-10-01

429

46 CFR 76.17-15 - Piping.  

Code of Federal Regulations, 2010 CFR

...of this chapter. (b) All piping, valves, and fittings of...the Commandant. (c) All piping, valves, and fittings shall...protected against injury. (d) Drains and dirt traps shall be fitted...of dirt or moisture. (e) Piping shall be used for no other...

2010-10-01

430

46 CFR 108.447 - Piping.  

Code of Federal Regulations, 2011 CFR

...108.447 Piping. (a) Each pipe, valve, and fitting in a CO2...80 (extra heavy). (c) Each pipe, valve, and fitting made of ferrous...CO2 system must have drains and dirt traps located where dirt or moisture can accumulate in...

2011-10-01

431

46 CFR 182.455 - Fuel piping.  

Code of Federal Regulations, 2010 CFR

...fuel lines, including pipe, tube, and hose, must...such as seamless steel pipe or tubing, which provide...fuel lines, including pipe, tube, and hose, must...at the tank is located inside the machinery space...of opening on top for cleaning screens. A drip...

2010-10-01

432

46 CFR 182.455 - Fuel piping.  

Code of Federal Regulations, 2011 CFR

...fuel lines, including pipe, tube, and hose, must...such as seamless steel pipe or tubing, which provide...fuel lines, including pipe, tube, and hose, must...at the tank is located inside the machinery space...of opening on top for cleaning screens. A drip...

2011-10-01

433

46 CFR 119.455 - Fuel piping.  

Code of Federal Regulations, 2011 CFR

...fuel lines, including pipe, tube, and hose, must...such as seamless steel pipe or tubing, which provide...fuel lines, including pipe, tube, and hose, must...at the tank is located inside the tank compartment...type opening on top for cleaning screens. Fuel...

2011-10-01

434

46 CFR 119.455 - Fuel piping.  

Code of Federal Regulations, 2010 CFR

...fuel lines, including pipe, tube, and hose, must...such as seamless steel pipe or tubing, which provide...fuel lines, including pipe, tube, and hose, must...at the tank is located inside the tank compartment...type opening on top for cleaning screens. Fuel...

2010-10-01

435

Assessment of socket weld integrity in pipings  

Microsoft Academic Search

The operating experience showed that the fatigue is one of the major piping failure mechanisms in nuclear power plants (NPPs). The pressure and\\/or temperature loading transients, the vibration, and the mechanical cyclic loading during the plant operation may induce the fatigue failure in the nuclear piping. Recently, many fatigue piping failure occurred at the socket weld area have been widely

Young Hwan Choi; Sun Yeong Choi

2009-01-01

436

FIELD STUDIES OF IMPREGNATED CONCRETE PIPE  

EPA Science Inventory

The follow-on study (initiated in June 1980) continued to monitor performance of 1,400 ft of impregnated concrete pipe installed in several Texas cities. The performance of concrete pipe has been compared with that of sulfur-impregnated concrete pipe; hydrofluoric acid (HF)-treat...

437

Heat pipes for sun energy conversion  

Microsoft Academic Search

Heat pipes fabricated from copper and employing organic fluids or water as the working fluid have been developed for use with solar collectors. The gravity pipes were tested for operation at angles of inclination from 0 to 90 deg. A porous structure (glass wool) was adopted to assure efficient circulation of the fluid. Data for heat pipes tested with acetone,

Z. Murgu; D. Murgu; L. Cojocaru; M. Huzum; E. Tvardochlieb

1978-01-01

438

Thermal Performance of High Temperature Titanium -- Water Heat Pipes by Multiple Heat Pipe Manufacturers  

NASA Technical Reports Server (NTRS)

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.

Sanzi, James L.

2007-01-01

439

Thermal Performance of High Temperature Titanium-Water Heat Pipes by Multiple Heat Pipe Manufacturers  

NASA Technical Reports Server (NTRS)

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.

Sanzi, James L.

2007-01-01

440

Evanescent waves propagation along a periodically corrugated surface and their amplification by relativistic electron beam (quasi-optical theory)  

SciTech Connect

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.

Ginzburg, N. S.; Malkin, A. M.; Zheleznov, I. V.; Sergeev, A. S. [Institute of Applied Physics of the Russian Academy of Sciences, 46, Ul'yanov St., Nizhny Novgorod (Russian Federation)] [Institute of Applied Physics of the Russian Academy of Sciences, 46, Ul'yanov St., Nizhny Novgorod (Russian Federation)

2013-06-15

441

Evaporation heat transfer and friction characteristics of R-134a flowing downward in a vertical corrugated tube  

SciTech Connect

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)

Aroonrat, Kanit; Wongwises, Somchai [Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Lab. (FUTURE), Department of Mechanical Engineering, King Mongkut's University of Technology Thonburi, Bangmod, Bangkok 10140 (Thailand)

2011-01-15

442

Transient, turbulent, smooth pipe friction  

Microsoft Academic Search

Two of the most promising analytical models of unsteady friction in turbulent pipe flows are based on sharply contrasting hypotheses. One uses the history of the flow; the other uses instantaneous conditions. The purposes of this paper are to present an analysis using the former approach and to indicate how to determine which of the two methods is appropriate.A weighting

Alan E. Vardy; Jim M. B. Brown

1995-01-01

443

Characterization of accelerating pipe flow  

Microsoft Academic Search

A unique series of experiments was conducted to determine the effects of constant acceleration on the flow in a 5-cm-diameter pipe. These experiments, which differed substantially from those of previous researchers, investigated such phenomena as transition to turbulence and the general physics of the effect acceleration has on various flow parameters such as wall shear stress, velocity profile, and turbulence

Paul J. Lefebvre

1988-01-01

444

Characterization of accelerating pipe flow  

Microsoft Academic Search

A unique series of experiments was conducted to determine the effects of constant acceleration on the flow in a 5-cm diameter pipe. These experiments, which differed substantially from those of previous researchers, investigated such phenomena as transition to turbulence and the general physics of the effect acceleration has on various flow parameters such as well shear stress, velocity profile, and

1987-01-01

445

Ceramic heat pipe heat exchangers  

Microsoft Academic Search

High-temperature strength, resistance to corrosive atmospheres, and moderate cost combine to make ceramic materials an obvious choice for construction of high-temperature thermal energy recuperator systems. Despite these advantages, ceramic recuperators are steadily being replaced by metallic units at considerable sacrifice in maximum air or fuel preheat temperatures and hence in recovery efficiency. By constructing a recuperator from ceramic heat pipes,

W. A. Ranken

1976-01-01

446

Understanding the Response of Pipe-in-pipe Deepwater Riser Systems  

Microsoft Academic Search

Pipe-in-pipe top tensioned risers, in the forms of TLP\\/Spar dry tree risers and freestanding hybrid risers, are used in numerous deepwater developments worldwide. During the detail design of pipe-in-pipe systems, the complex interactions between the pipes are often misunderstood, leading to conservatism or possible errors in the estimation of the system fatigue life. This paper aims to provide an explanatory

I. Harrison

2007-01-01

447

Single-step holographic fabrication of large-area periodically corrugated metal films  

NASA Astrophysics Data System (ADS)

We have developed a simple, high-throughput, and cost-effective method to fabricate one-dimensional and two-dimensional periodically corrugated silver films over centimeter scale areas. This fabrication uses a single-step holographic patterning technique with laser intensities as low as 88.8 mW/cm2 to deposit silver nanoparticles directly from solution to create gratings with periodicities of 570 nm. A dip in the transmission spectrum for these samples is observed due to certain visible wavelengths coupling to surface plasmon polaritons (SPPs) and the peak wavelength of this dip has a linear relationship with the surrounding material's refractive index (RI) with a sensitivity of 553.4 nm/RIU. The figure of merit (the ratio of refractive index sensitivity to the full width at half maximum (FWHM)) is typically in the range of 12-23. Our technique enables single-step fabrication of uniform, sub-wavelength periodic metal structures over a large area with low cost. Such sub-wavelength periodic metal structures are promising candidates as disposable sensors in applications such as affordable environmental monitoring systems and point-of-care diagnostics.

Lu, Mengqian; Krishna Juluri, Bala; Zhao, Yanhui; Jun Liu, Yan; Bunning, Timothy J.; Jun Huang, Tony

2012-12-01

448

Anomalous Features of Diffusion in Corrugated Potentials with Spatial Correlations: Faster than Normal, and Other Surprises  

NASA Astrophysics Data System (ADS)

Normal diffusion in corrugated potentials with spatially uncorrelated Gaussian energy disorder famously explains the origin of non-Arrhenius exp[-?2/(kBT2)] temperature dependence in disordered systems. Here we show that unbiased diffusion remains asymptotically normal also in the presence of spatial correlations decaying to zero. However, because of a temporal lack of self-averaging, transient subdiffusion emerges on the mesoscale, and it can readily reach macroscale even for moderately strong disorder fluctuations of ? 4-5kBT. Because of its nonergodic origin, such subdiffusion exhibits a large scatter in single-trajectory averages. However, at odds with intuition, it occurs essentially faster than one expects from the normal diffusion in the absence of correlations. We apply these results to diffusion of regulatory proteins on DNA molecules and predict that such diffusion should be anomalous, but much faster than earlier expected on a typical length of genes for a realistic energy disorder of several room kBT, or merely 0.05-0.075 eV.

Goychuk, Igor; Kharchenko, Vasyl O.

2014-09-01

449

On the modeling of modes coupling in dissipative fluid-filled waveguide with corrugated surfaces  

NASA Astrophysics Data System (ADS)

This paper aims at providing an alternative analytical model, which would be more suitable than a previous one [C. Potel and M. Bruneau, J. Sound Vib. 313, 738 (2008)], to describe the mode coupling due to scattering on small one-dimensional irregularities (parallel ridges) of the surfaces of a fluid-filled waveguide. Both models rely on standard integral formulation and modal analysis, the acoustic field being expressed as a coupling between eigenmodes of a regularly shaped waveguide, which bounds outwardly the corrugated waveguide considered. But the model presented here departs from the previous one essentially because it starts from the integral formulation for the acoustic pressure field, the solution relying on a modal expansion, whereas the previous one starts from the inner product of the set of differential equations (which govern the acoustic pressure field) and the appropriate eigenfunctions, the solution being obtained from using a one-dimensional integral formulation. Substituting this alternative model for the previous one clearly accelerates convergences (even permits to avoid divergences) of the iterative process used to solve the problem. Finally, complex eigenfunctions are introduced here in order to account for the dissipative effects due to thermoviscous phenomena (through an impedancelike boundary condition), which is of importance at the cut-off frequencies.

Valier-Brasier, Tony; Potel, Catherine; Bruneau, Michel

2009-08-01

450

Boundary-layer flow over corrugated surfaces: alternatives to the Falkner-Skan solutions  

NASA Astrophysics Data System (ADS)

We consider similarity-type boundary-layer flows over corrugated surfaces with transverse and lateral dimensions comparable to the boundary layer thickness. The governing equations are similar to those studied in the context of corner boundary-layer flows by Dhanak & Duck (1997). As in this previous work, a thorough understanding of the far-field conditions is necessary, and this leads us to investigate a system of equations analogous to the Falkner-Skan-type, but which allows for a crossflow component of velocity, linearly increasing in the crossflow direction. It is found that even when the freestream crossflow velocity is zero, in addition to the classical Falkner-Skan family of solutions, another solution family is also present, comprising a jet-like crossflow. An investigation of the streamwise development of the flow (with the similarity constraint removed) leads in many circumstances (including the classical Blasius boundary-layer solution) to leading-edge eigensolutions, which render standard numerical marching procedures ill-posed.

Duck, Peter W.; Dhanak, Manhar R.

1998-11-01

451

Planar surface plasmonic waveguide devices based on symmetric corrugated thin film structures.  

PubMed

Recently, a conformal surface plasmon (CSP) structure has been successfully proposed, which is very promising for application of planar plasmonic devices in the frequency ranging from microwave to mid-infrared [Proc. Natl. Acad. Sci. U.S.A. 110, 40-45 (2013)]. Here we investigated the dispersions and electromagnetic (EM) field patterns of a symmetric CSP structure in which the two sides of the planar metal strip are symmetrically corrugated by groove arrays. The symmetric CSP structure can support both the symmetric mode (even mode) and the anti-symmetric mode (odd mode) of surface wave propagation. Based on the even mode, we analyzed the EM wave coupling between two adjacent symmetry CSP strips, and then designed and analyzed two planar CSP waveguide devices in the terahertz frequency: a frequency splitter and a 3 dB directional coupler. To verify the functionality and performance of these waveguide devices, we scaled down the working frequency to microwave and designed similar devices with scaled geometry. We implemented microwave experiments on the fabricated prototypes, and the tested device performances have clearly validated the functionality of our designs. The symmetric CSP structure is believed to be very applicable in future design of novel planar plasmonic device and circuitry. PMID:25321220

Liu, Xiaoyong; Feng, Yijun; Chen, Ke; Zhu, Bo; Zhao, Junming; Jiang, Tian

2014-08-25

452

High-power corrugates waveguide components for mm-wave fusion heating systems  

SciTech Connect

Considerable progress has been made over the last year in the U.S., Japan, Russia, and Europe in developing high power long pulse gyrotrons for fusion plasma heating and current drive. These advanced gyrotrons typically operate at a frequency in the range 82 GHz to 170 GHz at nearly megawatt power levels for pulse lengths up to 5 s. To take advantage of these new microwave sources for fusion research, new and improved transmission line components are needed to reliably transmit microwave power to plasmas with minimal losses. Over the last year, General Atomics and collaborating companies (Spinner GmbH in Europe and Toshiba Corporation in Japan) have developed a wide variety of new components which meet the demanding power, pulse length, frequency, and vacuum requirements for effective utilization of the new generation of gyrotrons. These components include low-loss straight corrugated waveguides, miter bends, miter bend polarizers, power monitors, waveguide bellows, de breaks, waveguide switches, dummy loads, and distributed windows. These components have been developed with several different waveguide diameters (32, 64, and 89 mm) and frequency ranges (82 GHz to 170 GHz). This paper describes the design requirements of selected components and their calculated and measured performance characteristics.

Olstad, R.A.; Doane, J.L.; Moeller, C.P.; O`Neill, R.C.; Di Martino, M.

1996-10-01

453

Shock Corrugation by Rayleigh-Taylor Instability in GRB Afterglow Jets  

E-print Network

Afterglow jets are Rayleigh-Taylor unstable and therefore turbulent during the early part of their deceleration. There are also several processes which actively cool the jet. In this letter, we demonstrate that if cooling significantly increases the compressibility of the flow, the turbulence collides with the forward shock, destabilizing and corrugating it. In this case, the forward shock is turbulent enough to produce the magnetic fields responsible for synchrotron emission via small scale turbulent dynamo. We calculate light curves assuming the magnetic field is in energy equipartition with the turbulent kinetic energy and discover that dynamic magnetic fields are well-approximated by a constant magnetic-to- thermal energy ratio of 1%, though there is a sizeable delay in the time of peak flux as the magnetic field turns on only after the turbulence has activated. The reverse shock is found to be significantly more magnetized than the forward shock, with a magnetic-to-thermal energy ratio of order 10%. This...

Duffell, Paul

2014-01-01

454

Shock Corrugation by Rayleigh-Taylor Instability in Gamma-Ray Burst Afterglow Jets  

NASA Astrophysics Data System (ADS)

Afterglow jets are Rayleigh-Taylor unstable and therefore turbulent during the early part of their deceleration. There are also several processes which actively cool the jet. In this Letter, we demonstrate that if cooling significantly increases the compressibility of the flow, the turbulence collides with the forward shock, destabilizing and corrugating it. In this case, the forward shock is turbulent enough to produce the magnetic fields responsible for synchrotron emission via small-scale turbulent dynamo. We calculate light curves assuming the magnetic field is in energy equipartition with the turbulent kinetic energy and discover that dynamic magnetic fields are well approximated by a constant magnetic-to-thermal energy ratio of 1%, though there is a sizeable delay in the time of peak flux as the magnetic field turns on only after the turbulence has activated. The reverse shock is found to be significantly more magnetized than the forward shock, with a magnetic-to-thermal energy ratio of the order of 10%. This work motivates future Rayleigh-Taylor calculations using more physical cooling models.

Duffell, Paul C.; MacFadyen, Andrew I.

2014-08-01

455

Pressure drop testing of corrugated stainless steel pliable gas tubing (PLT)  

NASA Astrophysics Data System (ADS)

An experimental program was initiated to determine the Darcy friction factor in straight corrugated stainless steel pliable gas tubing (PLT). Pressure loss tests were conducted on PLT per I.S. EN 15266:2007. A power law least-squares curve fit was used to relate pressure loss per unit length as a function of volume flow rate. The calculated coefficient of determination values for the straight PLT exceeded 0.90 indicating suitable correlation. Darcy friction factors were calculated from test data for each case and plotted on a Moody diagram as a function of Reynolds number based on the minimum PLT cross section. For Reynolds numbers less than 2300 the pressure loss data for PLT yielded an inverse relationship between the Darcy friction factor and the Reynolds number, with a proportionality coefficient of 49. The measurement uncertainty estimates for straight sections was performed with a 95% confidence level. Straight PLT flow rates for air and representative fuel gases that would yield a pressure loss Deltap = 1 mbar were calculated as a function of PLT length and diameter. Fitting pressure loss tests were performed for elbows, tees, and bullhead tees. The loss coefficients were evaluated and tabulated. The calculated coefficient of determination values for the fittings was found to be low. The measurement uncertainty was calculated using the root sum square error method and was found to be very high because of the low flow rates considered in this experiment.

Srinivasan, Bharadwaj

456

Ratcheting of Brownian swimmers in periodically corrugated channels: A reduced Fokker-Planck approach  

NASA Astrophysics Data System (ADS)

We consider the motion of self-propelling Brownian particles in two-dimensional periodically corrugated channels. The point-size swimmers propel themselves in a direction which fluctuates by Brownian rotation; in addition, they undergo Brownian motion. The impermeability of the channel boundaries in conjunction with an asymmetry of the unit-cell geometry enables ratcheting, where a nonzero particle current is animated along the channel. This effect is studied here in the continuum limit using a diffusion-advection description of the probability density in a four-dimensional position-orientation space. Specifically, the mean particle velocity is calculated using macrotransport (generalized Taylor-dispersion) theory. This description reveals that the ratcheting mechanism is indirect: swimming gives rise to a biased spatial particle distribution which in turn results in a purely diffusive net current. For a slowly varying channel geometry, the dependence of this current upon the channel geometry and fluid-particle parameters is studied via a long-wave approximation over a reduced two-dimensional space. This allows for a straightforward seminumerical solution. In the limit where both rotational diffusion and swimming are strong, we find an asymptotic approximation to the particle current, scaling inversely with the square of the swimming Pclet number. For a given swimmer-fluid system, this limit is physically realized with increasing unit-cell size.

Yariv, Ehud; Schnitzer, Ory

2014-09-01

457

Evaluation of a tri-wall corrugated fibreboard package for packaging and transporting LSA nonretrievable waste  

SciTech Connect

An evaluation was conducted to determine if an economical Tri-Wall Corrugated Fiberboard (TWCF) Package could be used for transporting LSA nonretrievable wastes (< 10 nCi/g radioactive contamination). A complete description of the packaging configuration was given. The evaluation included Vibration Tests to determine if the TWCF Package would comply with the present DOT regulation for packaging LSA waste (i.e. the package must be a strong-tight package that will not leak material under conditions normally incident to transport). Presently, no specific tests are required to determine compliance. Additional tests were conducted to determine performance of the package under selected adverse and hypothetical accidental conditions. No significant damage or loss of waste material occurred during the Vibration Tests thus indicating compliance with the present DOT regulation. The other performance tests indicated that some loss of waste material would occur under certain accidental conditions, however, the loss would be minimal. As a result of these performance tests, certain operating limitations and precautions regarding the handling and use of the package were given. Since the TWCF Package appears to meet DOT regulations and performed favorably under certain selected adverse and hypothetical accidential conditions, it was recommended for use in transporting certain types and forms of LSA nonretrievable wastes.

Saiki, D.M.; Aguilar, P.G.

1981-01-01

458

Heat pipes in space and on earth  

NASA Technical Reports Server (NTRS)

The performance of heat pipes used in the thermal control system of spacecraft such as OAO-III and ATS-6 is discussed, and applications of heat pipes to permafrost stabilization on the Alaska Pipeline and to heat recovery systems are described. Particular attention is given to the ATS-6, launched in 1974, which employs 55 heat pipes to carry solar and internal power loads to radiator surfaces. In addition, experiments involving radiative cooling based on cryogenic heat pipes have been planned for the Long Duration Exposure Facility spacecraft and for Spacelab. The role of heat pipes in Space Shuttle heat rejection services is also mentioned.

Ollendorf, S.

1978-01-01

459

Practical aspects of acoustic plastic pipe location  

SciTech Connect

Many gas distribution company operation and maintenance activities require precise knowledge of the location of buried plastic piping. Plastic pipe cannot be located if the tracer wire is gone or was never installed. Under sponsorship of the Southern California Gas Company, IGT successfully demonstrated an acoustic plastic pipe location technique and is developing the technique into a practical field instrument an acoustic signal is injected directly into the gas at a service. The acoustic signal travels in the gas in the pipes, not in the pipe wall. As the acoustic wave travels along the pipe, some of the sound radiates from the pipe through the soil to the surface of the ground. An array of sensors on the surface of the ground perpendicular to the pipe detects the acoustic signal, thereby locating the Pipe. Two different acoustic measurements are used. The first measurement locates the pipe to within {plus_minus} 3-ft. Then the second technique determines the location of the pipe to within {plus_minus} 6-in.

Huebler, J.E.; Campbell, B.K. [Institute of Gas Technology, Chicago, IL (United States); Ching, G.K. [Southern California Gas Co. (United States)

1993-12-31

460

SAFE Alkali Metal Heat Pipe Reliability  

NASA Astrophysics Data System (ADS)

Alkali metal heat pipes are among the best understood and tested of components for first generation space fission reactors. A flight reactor will require production of a hundred or more heat pipes with assured reliability over a number of years. To date, alkali metal heat pipes have been built mostly in low budget development environments with little formal quality assurance. Despite this, heat pipe test samples suggest that high reliability can be achieved with the care justified for space flight qualification. Fabrication procedures have been established that, if consistently applied, ensure long-term trouble-free heat pipe operation. Alkali metal heat pipes have been successfully flight tested in micro gravity and also have been shown capable of multi-year operation with no evidence of sensitivity to fast neutron fluence up to 1023 n/cm2. This represents 50 times the fluence of the proposed Safe Affordable Fission Engine (SAFE-100) heat pipe reactor core.

Reid, Robert S.

2003-01-01

461

System for Testing Thermal Insulation of Pipes  

NASA Technical Reports Server (NTRS)

An apparatus and method have been developed for measuring the rates of leakage of heat into pipes carrying liquids, the purpose of the measurements being to quantify the thermal performance of the insulation system. The apparatus is designed primarily for testing pipes used to carry cryogenic liquids, but can also be used for measuring the thermal performance of other insulated pipes or piping systems. The basic measurement principle is straightforward: The outer surface of the pipe insulation is maintained at a fixed warmer temperature. The interior of the pipe is maintained in a narrow fixed lower-temperature range by means of a regular liquid (e.g., water) that is pumped through the pipe at a known flow rate or a cryogenic liquid (e.g., nitrogen) that is saturated at atmospheric pressure and replenished until steady-state conditions are achieved. In the case of water or another liquid pumped through, the inlet and outlet temperatures are measured and heat-leak power is calculated as the mass flow rate of the liquid multiplied by the specific heat of the liquid multiplied by the inlet-to-outlet temperature rise of the liquid. In the case of liquid nitrogen or another low-temperature boiling liquid, the heat-leak power is calculated as the rate of boil-off multiplied by the latent heat of vaporization of the liquid. Then the thermal-insulation performance of the pipe system can be calculated as a function of the measured heat-leak power, the inner and outer boundary temperatures, and the dimensions of the pipe. The apparatus can test as many as three pipes simultaneously. The pipes can have inner diameters up to .15 cm and outer diameters up to .20 cm. The lengths of the pipes may vary; typical lengths are of the order of 18 m. Two thermal guard boxes . one for each end of the pipe(s) under test . are used to make the inlet and outlet fluid connections to the pipe(s) (see figure). The connections include bellows that accommodate thermal expansion and contraction of the pipes. The guard boxes and pipe(s) are positioned so that the pipe(s) slope upward from the upstream to the downstream end at an angle of at least 2 . The upward slope allows vapor bubbles to accumulate at the downstream end. The thermal guard boxes keep the ends of the pipes at the lower interior temperature to prevent spurious lengthwise leakage of heat into the pipes. It is important to prevent this spurious heat leakage because, if it were allowed to occur, it could contribute a large error in the measured heat-leak power. The upstream thermal guard box includes a heat exchanger through which liquid flowing into the pipe(s) is subcooled to the saturation temperature corresponding to the ambient pressure. Conversely, this heat exchanger can also be used to warm the flowing liquid to a desired fixed temperature. The apparatus includes a temperature control device that is placed around each pipe under test. Each device is operated under thermostatic control to maintain the outer surface of the pipe insulation at the specified test temperature. All measurements are recorded on a portable data-acquisition system.

Fesmire, James E.; Augustynowicz, Stanislaw D.; Nagy, Zoltan F.

2003-01-01

462

Heat Pipes for Alaskan Oil  

NASA Technical Reports Server (NTRS)

McDonnel Douglas Corporation is using a heat-pipe device, developed through the space program, to transport oil from Alaska's rich North Slope fields. It is being used to keep the ground frozen along the 798- mile pipeline saving hundreds of millions of dollars and protecting the tundra environment. Heatpipes are totally automatic, they sense and respond to climatic conditions with no moving parts, require no external power, and never need adjustment or servicing.

1976-01-01

463

Mode Content Determination of Terahertz Corrugated Waveguides Using Experimentally Measured Radiated Field Patterns  

PubMed Central

This work focuses on the accuracy of the mode content measurements in an overmoded corrugated waveguide using measured radiated field patterns. Experimental results were obtained at 250 GHz using a vector network analyzer with over 70 dB of dynamic range. The intensity and phase profiles of the fields radiated from the end of the 19 mm diameter helically tapped brass waveguide were measured on planes at 7, 10, and 13 cm from the waveguide end. The measured fields were back propagated to the waveguide aperture to provide three independent estimates of the field at the waveguide exit aperture. Projecting that field onto the modes of the guide determined the waveguide mode content. The three independent mode content estimates were found to agree with one another to an accuracy of better than 0.3%. These direct determinations of the mode content were compared with indirect measurements using the experimentally measured amplitude in three planes, with the phase determined by a phase retrieval algorithm. The phase retrieval technique using the planes at 7, 10, and 13 cm yielded a mode content estimate in excellent agreement, within 0.3%, of the direct measurements. Phase retrieval results using planes at 10, 20, and 30 cm were less accurate due to truncation of the measurement in the transverse plane. The reported measurements benefited greatly from a precise mechanical alignment of the scanner with respect to the waveguide axis. These results will help to understand the accuracy of mode content measurements made directly in cold test and indirectly in hot test using the phase retrieval technique.

Jawla, Sudheer K.; Nanni, Emilio A.; Shapiro, Michael A.; Woskov, Paul P.; Temkin, Richard J.

2012-01-01

464

Furan flare piping rupture analysis  

SciTech Connect

The FRP flare piping is part of a typical flare system that is used to burn gases from the relief valves in the area, vent gases when the incinerator is down and vents from selected towers. All exhaust gases enter a large flare seal pot where a water seal is maintained. These gases are ignited by a continuous natural gas pilot with propane used as a back-up. A 12 inch (305 mm) diameter FRP piping section containing Furan resin disintegrated after four years of service in a vapor relief system. External inspection of the flare stack conducted just three months earlier revealed no obvious problems. Also, during the ensuring period, there were no upsets in temperature, pressure or process operations. A detailed investigation determined that excessive mechanical stresses at the unsupported 45 degree elbow joints led to strain corrosion and subsequent crumbling of the FRP material. The remainder of the piping and flanges were in good condition. Steps necessary to minimize future problems and the need for industry wide design, inspection and maintenance guidelines are discussed.

Dias, O.C. [Lyondell-Citgo Refining, Houston, TX (United States)

1997-08-01

465

Hot Leg Piping Materials Issues  

SciTech Connect

With Naval Reactors (NR) approval of the Naval Reactors Prime Contractor Team (NRPCT) recommendation to develop a gas cooled reactor directly coupled to a Brayton power conversion system as the space nuclear power plant (SNPP) for Project Prometheus (References a and b) the reactor outlet piping was recognized to require a design that utilizes internal insulation (Reference c). The initial pipe design suggested ceramic fiber blanket as the insulation material based on requirements associated with service temperature capability within the expected range, very low thermal conductivity, and low density. Nevertheless, it was not considered to be well suited for internal insulation use because its very high surface area and proclivity for holding adsorbed gases, especially water, would make outgassing a source of contaminant gases in the He-Xe working fluid. Additionally, ceramic fiber blanket insulating materials become very friable after relatively short service periods at working temperatures and small pieces of fiber could be dislodged and contaminate the system. Consequently, alternative insulation materials were sought that would have comparable thermal properties and density but superior structural integrity and greatly reduced outgassing. This letter provides technical information regarding insulation and materials issues for the Hot Leg Piping preconceptual design developed for the Project Prometheus space nuclear power plant (SNPP).

V. Munne

2006-07-19

466

Pipe lifting hook having clamp assembly  

SciTech Connect

A pipe lifting hook is provided having a generally ''C'' shaped hook member having an elongated lower portion being insertable within the end of a joint of pipe and having an upper portion positionable above the pipe and provided with lifting connection means. The hook member is frictionally clamped to the pipe by grip shoe means that is movably supported by the upper portion of the hook member and is selectably movable from a released position out of contact with said pipe to a locked position in frictional locking engagement with the outer surface of the pipe. A ratchet mechanism couples said grip shoe means to the upper portion of the hook member and is manually positionable to lock said grip shoe means at said locked position or release said grip shoe means for movement toward said released position thereof.

Codner, J.A.

1984-06-12

467

Piping inspection carriage having axially displaceable sensor  

DOEpatents

A pipe inspection instrument carriage for use with a pipe crawler for performing internal inspections of piping surfaces. The carriage has a front leg assembly, a rear leg assembly and a central support connecting the two assemblies and for mounting an instrument arm having inspection instruments. The instrument arm has a y-arm mounted distally thereon for axially aligning the inspection instrumentation and a mounting block, a linear actuator and axial movement arm for extending the inspection instruments radially outward to operably position the inspection instruments on the piping interior. Also, the carriage has a rotation motor and gear assembly for rotating the central support and the front leg assembly with respect to the rear leg assembly so that the inspection instruments azimuthally scan the piping interior. The instrument carriage allows performance of all piping inspection operations with a minimum of moving parts, thus decreasing the likelihood of performance failure.

Zollinger, William T. (Martinez, GA); Treanor, Richard C. (Augusta, GA)

1994-01-01

468

Heat-Pipe-Cooled Leading Edges for Hypersonic Vehicles  

NASA Technical Reports Server (NTRS)

Heat pipes can be used to effectively cool wing leading edges of hypersonic vehicles. . Heat-pipe leading edge development. Design validation heat pipe testing confirmed design. Three heat pipes embedded and tested in C/C. Single J-tube heat pipe fabricated and testing initiated. HPCLE work is currently underway at several locations.

Glass, David E.

2006-01-01

469

Expansion compensation of pipe in underground heat-distribution systems  

SciTech Connect

When pipe is not free to expand with changes of temperature, damage to the pipe or attaching equipment may occur. Pipe expansion may be accommodated by mechanical devices or the natural flexibility of the pipe itself. Stress analysis of flexible piping must consider the use of guides or restraints due to the limited expansion space in underground systems.

Couch, R.O.

1983-06-01

470

Study into thermal stresses due to turbulent flow in pipes  

Microsoft Academic Search

Flow through pipes with heat transfer finds wide applications in industry. The thermal stresses, which develop in the pipe limit the heat transfer rate in pipe flow. In the present study, a turbulent flow in thick pipe with external heating is considered. The flow and temperature fields in a pipe and in the fluid are predicted using a numerical scheme;

I. T. Al-Zaharnah; B. S. Yilbas; M. S. J. Hashmi

2004-01-01

471

Grade-tonnage and other models for diamond kimberlite pipes  

Microsoft Academic Search

Grade-tonnage and other quantitative models help give reasonable answers to questions about diamond kimberlite pipes. Diamond kimberlite pipes are those diamondiferous kimberlite pipes that either have been worked or are expected to be worked for diamonds. These models are not applicable to kimberlite dikes and sills or to lamproite pipes. Diamond kimberlite pipes contain a median 26 million metric tons

James D. Bliss

1992-01-01

472

Heat pipe implications for district energy systems  

SciTech Connect

The heat pipe is a very adaptable heat transfer device which could have a large impact on district energy systems. The heat pipe is a very simple (no moving parts), passive, fast acting heat transfer device which does not require pumps, valves, or a large cross sectional area. The heat pipe can be adapted for primary and secondary heat transfer loop applications for district heating and cooling as well as dehumidification, thermal storage, passive defrost and heat recovery.

Cooper, J.T. [Heat Pipe Technology, Inc, Alachua, FL (United States)

1995-09-01

473

Thermal performance of insulated pipe systems  

SciTech Connect

The thermal performance of insulated pipe systems was measured as a function of insulation and pipe system parameters. Insulation parameters included insulation material, thickness, and air gaps at seams and joints. Pipe system parameters were pipe size, hangers, supports, and operating temperature. Over 150 thermal performance tests were recorded and analyzed over a two-year period. Test results show a 15 percent deterioration in thermal performance for a 305-mm (1-ft) insulated pipe section with a 6.4-mm (0.25-in.) butt-joint air gap. The method of insulating pipe hangers and supports is a major component of pipe system heat analysis. Glass fiber and calcium silicate pipe insulations were tested with a variety of hanger and support configurations. The magnitude of heat loss was recorded as a function of several parameters including the degree of hanger/support insulation. A 305-mm (1-ft) glass fiber pipe insulation section containing a hanger had an additional 14 to 40 percent heat loss, depending on the hanger insulation, compared to that of an uninterrupted insulated pipe section. Results from the data analysis and ASTM Practice for Determination of Heat Gain or Loss and Surface Temperature of Insulated Pipe and Equipment Systems by the Use of a Computer Program (C 680) were combined to form computer program HEATLOSS. The good correlation between the thermal performance predicted by HEATLOSS and the actual test data indicates that HEATLOSS can be used to estimate thermal performance effects from variations in insulating material and pipe system design.

Sullivan, J.M.

1981-12-01

474

Downhole pipe selection for acoustic telemetry  

DOEpatents

A system for transmitting signals along a downhole string including a plurality of serially connected tubular pipes such as drill or production pipes, a transmitter for transmitting a signal along the string and a receiver for receiving the signal placed along the string at a location spaced from said transmitting means, wherein the pipes between the transmitter and the receiver are ordered according to length of tube to minimize loss of signal from said transmitter to said receiver.

Drumheller, Douglas S. (Cedar Crest, NM)

1995-01-01

475

Downhole pipe selection for acoustic telemetry  

DOEpatents

A system is described for transmitting signals along a downhole string including a plurality of serially connected tubular pipes such as drill or production pipes, a transmitter for transmitting a signal along the string and a receiver for receiving the signal placed along the string at a location spaced from said transmitting means, wherein the pipes between the transmitter and the receiver are ordered according to length of tube to minimize loss of signal from said transmitter to said receiver. 7 figs.

Drumheller, D.S.

1995-12-19

476

Creasing Characteristics of A-Flute Corrugated Fiber Board Using a Rotary Creaser with Respect to Breaking Strength  

NASA Astrophysics Data System (ADS)

This paper reports on bending-moment characteristics of heightwise/vertical crease of a corrugated fiberboard, a scored line of which is in parallel to the inner flute structure, and the effect of mechanical processing conditions on a failure phenomena of liner sheet scored by a rotary creaser. Regarding the dispersion and the variance of folding resistance, the creaser/pre-creaser gaps, the deviation of scored line from the inner flute apex, the diameter of creaser rolls and the effect of humidity on the material properties were experimentally investigated using a proto-type rotary creaser and a bending strength tester.

Nagaswa, Shigeru; Takamatsu, Tomohiro; Fukuzawa, Yasushi; Tozuka, Yusuke

2011-01-01

477

Steam turbine exhaust pipe erosion prevention system  

SciTech Connect

This patent describes an erosion-prevention device for a fluid-carrying pipe means, the fluid comprising a discontinuous liquid phase portion, the device comprising: a. liner means of predetermined length and disposed concentrically within the pipe means with a predetermined clearance between the liner means and the pipe means, the clearance between the liner means and the pipe means defining an annular space. The liner means has opening means therethrough for diverting a liquid layer formed from the discontinuous liquid phase portion to the annular space the liner means affixed at the ends thereof to the pipe means; b. liner wick means positioned within and substantially filing the annular space; c. collection means disposed within the annular space positioned substantially parallel with the axis of the pipe means for collecting a substantial portion of the diverted liquid layer; d. liner drain means for draining the collected diverted liquid layer comprising drain pipe means in fluid communication with the collection means. The liquid layer which is formed by the erosion causing liquid phase droplets is diverted from the pipe means thereby diminishing the erosion of the pipe means.

Draper, R.; Silvestri, G.J. Jr.; Hargrove, H.G.

1986-11-18

478

Boomwhackers and End-Pipe Corrections  

NASA Astrophysics Data System (ADS)

End-pipe corrections seldom come to mind as a suitable topic for an introductory physics lab. Yet, the end-pipe correction formula can be verified in an engaging and inexpensive lab that requires only two supplies: plastic-tube toys called boomwhackers and a meterstick. This article describes a lab activity in which students model data from plastic tubes to arrive at the end-correction formula for an open pipe. Students also learn the basic mathematics behind the musical scale, and come to appreciate the importance of end-pipe physics in the engineering design of toy musical tubes.

Ruiz, Michael J.

2014-02-01

479

Modeling of transient heat pipe operation  

SciTech Connect

The overall goal is to gain a better understanding of the transient behavior of heat pipes operating under both normal and adverse conditions. Normal operation refers to cases where the capillary structure remains fully wetted. Adverse operation occurs when drying, re-wetting, choking, noncontinuum flow, freezing, thawing etc., occur within the heat pipe. The work was redirected towards developing the capability to predict operational behavior of liquid metal heat pipes used for cooling aerodynamic structures. Of particular interest is the startup of such heat pipes from an initially frozen state such as might occur during re-entry of a space vehicle into the Earth's atmosphere or during flight of hypersonic aircraft.

Colwell, G.T.; Hartley, J.G.

1985-02-01

480

Heat Pipe Precools and Reheats Dehumidified Air  

NASA Technical Reports Server (NTRS)

Precooling and reheating by heat pipe reduces operating costs of air-conditioning. Warm air returned from air-conditioned space and cooled air supplied are precooled and reheated, respectively, by each other through a heat pipe. Heat-pipe technology brought to bear on problem of conserving airconditioning energy in hot, humid environments. Any increase in the cost of equipment due to installation of heat-pipe heat exchangers expected to be recovered in energy savings during service period of 2 years or less.

Koning, R. C.; Boggs, W. H.; Barnett, U. R.; Dinh, K.

1986-01-01

481

Evaluation of pipe whip impacts on neighboring piping and walls of the Ignalina Nuclear Power Plant  

Microsoft Academic Search

Stress corrosion cracks have been discovered in Group Distribution Headers (GDH) at the Ignalina and Chernobyl Nuclear Power Plants. This increases the probability that a guillotine pipe break can occur that creates a whipping pipe (GDH) with the potential to damage surrounding structuresi.e. adjacent GDH and its attached piping or adjacent reinforced concrete compartment wall. The GDH is the most

Gintautas Dundulis; Eugenijus Uspuras; Ronald F. Kulak; Algirdas Marchertas

2007-01-01

482

Resolution of thermal striping issue downstream of a horizontal pipe elbow in stratified pipe flow  

Microsoft Academic Search

A thermally stratified pipe flow produced by a thermal transient when passing through a horizontal elbow as a result of secondary flow gives rise to large thermal fluctuations on the inner curvature wall of the downstream piping. These fluctuations were measured in a specially instrumented horizontal pipe and elbow system on a test set-up using water in the Mixing Components

T. M. Kuzay; K. E. Kasza

1985-01-01

483

Application of WinSRFR4 program to zigzag corrugated furrow irrigation in Bolivia  

NASA Astrophysics Data System (ADS)

Program WinSRFR4, developed by the Agricultural Research Service-U.S. Department of Agriculture, is used to perform surface irrigation evaluations, to establish appropriate irrigation parameters to get better irrigation efficiencies, to execute irrigation simulations and so to set several alternatives to the design of an irrigation. This paper aims to adapt WinSRFR4 program to zigzag corrugated furrow irrigation performed in the Andean regions of Bolivia. These irrigations are quite peculiar as they are carried out in areas with steep slope and with very low flow rates to avoid the risk of erosion. Besides of this, the flow rates are quite variable during the irrigation application. The greater length of the furrows is drawn on contours performing small jumps between consecutive contours. Available data are taken for seven irrigations for different periods of lettuce crop growth. First, a model that fits irrigations executed has been searched. For this, we have conducted a series of tests with the program WinSRFR4, being necessary to carry some simplifications given the peculiarity of this type of irrigation. The procedure consisted in determining the advance curves during irrigation. Later, the parameters of the Kostiakov - Lewis equation have been calculated by the method of Walker and Elliot. Although the furrow longitudinal profile was available, a mean slope was used at the time of establishing the model. WinSRFR provides a model of analyzed irrigation with a coefficient of determination ranged from R2 = 0.3520 to R2 = 0.9095. Finally, the errors obtained in the mass balances are between 2% and 14%. The model showed that application efficiencies ranged between 9% and 35%, rather poor, while runoff coefficients varied between 47% and 91%. Not too much importance is given to the fact that runoff occurs because runoff water is used in plots located at a lower level Irrigation simulations have been carried out using WinSRFR by changing the operation variables: flow rate and cutoff time. Relatively high application efficiencies are obtained when applied flow rates are low. Furthermore, runoff depth is greater with higher flow rates while the irrigation cutoff time is the one with the greatest influence on the percolation depth. As a conclusion, it can be remarked that with the reduction and homogenization of the applied flow rates and with the establishment of irrigation times of long duration, it can obtain acceptable application efficiencies. The use of WinSRFR program is essential since an acceptable model fit to real irrigation data is obtained.

Roldn Caas, Jos; Moreno Perez, Maria Fatima; Garcia Moreno, Francisco Javier; Chipana, Rene

2013-04-01

484

Dynamic and spatial behavior of a corrugated interface in the driven lattice gas model  

NASA Astrophysics Data System (ADS)

The spatiotemporal behavior of an initially corrugated interface in the two-dimensional driven lattice gas (DLG) model with attractive nearest-neighbors interactions is investigated via Monte Carlo simulations. By setting the system in the ordered phase, with periodic bo