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1

Singing Corrugated Pipes  

ERIC Educational Resources Information Center

Presents theoretical and experimental observations made with a musical toy called Hummer consisting of a corrugated flexible plastic tube about three-feet long and one-inch diam open at both ends. Included are descriptions of three new instruments: the Water Pipe, the Gas-Pipe Corrugahorn Bugle, and the Gas-Pipe Blues Corrugahorn. (CC)

Crawford, Frank S.

1974-01-01

2

Turbulent Open-Channel Flow in Circular Corrugated Culverts  

Microsoft Academic Search

This paper presents the results of a laboratory study of the velocity field in turbulent open-channel flow in a circular corrugated pipe of diameter D of 0.622 m for three slopes S of 0.55, 1.14, and 2.55% and a range of discharges from 30 to 200 L\\/s. The Manning n was found to be equal to 0.023. Velocities were relatively

S. A. Ead; N. Rajaratnam; C. Katopodis; F. Ade

2000-01-01

3

MEASURED RESPONSE OF A DEEPLY CORRUGATED BOX CULVERT TO THREE DIMENSIONAL SURFACE LOADS By  

Microsoft Academic Search

Metal box culverts constructed from 400mm by 150mm plate resist applied loads largely in flexure and design predominantly focuses on bending moments rather than the thrusts considered for conventional corrugated plate. Moment distributions, deformations and thrusts have been measured during tests conducted on a deep corrugated metal box culvert (span of 10m, rise of 2.4m) and are reported for a

Andrea C. Mak; Richard W. I. Brachman; Ian D. Moore

4

Corrugated pipe adhesive applicator apparatus  

DOEpatents

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

Shirey, R.A.

1983-06-14

5

Corrugated pipe as a beam dechirper  

NASA Astrophysics Data System (ADS)

We have studied the use of a metallic pipe with small corrugations for the purpose of passively dechirping, through its wakefield, a short, intense electron bunch. The corrugated pipe is attractive for this purpose because its wake: (i) has near maximal possible amplitude for a given aperture and (ii) has a relatively large oscillation wavelength, even when the aperture is small. We showed how the corrugated structure can satisfy dechirping requirements encountered in the NGLS project at LBNL [1]. We found that a linear chirp of -40 MeV/mm can be induced by an NGLS-like beam, by having it pass through a corrugated, metallic pipe of radius 3 mm, length 8.2 m, and corrugation parameters full depth 450 ?m and period 1000 ?m. This structure is about 15 times as effective in the role of dechirper as an S-band accelerator structure used passively.

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

2012-10-01

6

Corrugated Pipe as a Beam Dechirper  

SciTech Connect

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

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

2012-04-20

7

Impedance of Beam Pipes with Smooth Shallow Corrugations  

E-print Network

1 Impedance of Beam Pipes with Smooth Shallow Corrugations M.Dohlus Deutsches-sinusoidal corrugations has been investigated. It is shown that these effects are nonlinear with respect to the beam of a periodically corrugated beam pipe we estimate the monopole wakes caused by the resistivity and the surface

8

Improving the upstream passage of two galaxiid fish species through a pipe culvert  

Microsoft Academic Search

Movement between habitats in river fish assemblages is often restricted by instream structures such as culverts. The ability of diadromous common jollytail, Galaxias maculatus (Jenyns), and spotted galaxias, Galaxias truttaceus (Val.), to pass upstream through an in situ pipe culvert modified through the installation of baffles was assessed. Spoiler baffles (100 · 70 · 28 or 56 mm) were installed

J. I. M ACDONALD

9

Study of the use of truck tire beads as drainage pipe and analysis of the economics of tire disposal in Oklahoma. Part 1. Culverts. Final report  

SciTech Connect

In an attempt to find alternate ways of dealing with waste truck tires, a private tire recycling company developed a pipe from the tire bead and sidewall. The tire-pipe has seen limited use as a roadway drainage culvert. To encourage wider use of this product, an evaluation of pipe performance was performed. The evaluation consisted of (1) inspections of existing installations; (2) structural tests; and (3) leakage tests. The study found that the majority of installations were performing well. Compared with corrugated steel and fiberglass pipes, the tire-pipe exhibited favorable structural performance. An individual tire-pipe section was found to be watertight. However, when tested in the open-air (not in the ground), the tire-pipe joints were found to leak. Development of an improved end connection would improve the utility of the tire-pipe.

Everett, J.W.; Gattis, J.L.

1994-07-01

10

Impedance issue of corrugated beam pipe from CDF  

SciTech Connect

The CDF collaboration proposed to install a new corrugated beam pipe at the Tevatron interaction area in order to better monitor the interaction vertex. This note discuss the impedance implication of such a pipe.

Ng, King-Yuen

1993-06-01

11

78 FR 5715 - Construction and Maintenance-Culvert Pipe Selection  

Federal Register 2010, 2011, 2012, 2013, 2014

...be accepted by Public Roads. This Memorandum further...competition for other construction materials. To implement...Subjects in 23 CFR Part 635 Construction materials, Design-build...Transportation, Highways and roads, Culvert material types...follows: PART 635--CONSTRUCTION AND MAINTENANCE 0...

2013-01-28

12

Whistling of a pipe system with multiple side branches: Comparison with corrugated pipes  

Microsoft Academic Search

Corrugated pipes are widely used because they combine local rigidity with global flexibility. Whistling induced by flow through such pipes can lead to serious environmental and structural problems. The whistling of a multiple side branch system is compared to the whistling behavior of corrugated pipes. The study has been restricted to cavities with sharp edges which are convenient for theoretical

D. Tonon; B. J. T. Landry; S. P. C. Belfroid; J. F. H. Willems; G. C. J. Hofmans; A. Hirschberg

2010-01-01

13

ROAD CULVERTS ACROSS STREAMS WITH THE ENDANGERED TOPEKA SHINER, NOTROPIS TOPEKA, IN THE JAMES, VERMILLION, AND BIG SIOUX RIVER BASINS  

Microsoft Academic Search

We evaluated 232 installed corrugated pipe culverts at 81 sites where roads cross streams that have a high potential for Topeka shiner presence. Culvert con- ditions were characterized by the amount of perching, embeddedness, blockage, gradient and water velocity, and rated for potential as a barrier to upstream fish migration. Seven sites were classified as high priority for maintenance or

Steven S. Wall; Charles R. Berry

14

Wall shape optimization for a thermosyphon loop featuring corrugated pipes  

NASA Astrophysics Data System (ADS)

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

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

2012-06-01

15

Design, Construction, and Field-Testing of an RC Box Culvert Bridge Reinforced with GFRP Bars  

Microsoft Academic Search

This paper presents an overview of the design, construction, and laboratory and field testing of a box culvert bridge reinforced with glass FRP (GFRP) bars. The bridge was constructed to replace a bridge that was built in the early 1980s and consisted of three concrete-incased corrugated steel pipes. Due to excessive corrosion of the steel pipes, the original bridge became

TAREK ALKHRDAJI; ANTONIO NANNI

16

Terahertz radiation from a pipe with small corrugations  

NASA Astrophysics Data System (ADS)

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 ˜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.

2012-06-01

17

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

18

Responses of buried corrugated metal pipes to earthquakes  

SciTech Connect

This study describes the results of field investigations and analyses carried out on 61 corrugated metal pipes (CMP) that were shaken by the 1994 Northridge earthquake. These CMPs, which include 29 small-diameter (below 107 cm) CMPs and 32 large-diameter (above 107 cm) CMPs, are located within a 10 km{sup 2} area encompassing the Van Normal Complex in the Northern San Fernando Valley, in Los Angeles, California. During the Northridge earthquake, ground movements were extensively recorded within the study area. Twenty-eight of the small-diameter CMPs performed well while the 32 large-diameter CMPs underwent performances ranging from no damage to complete collapse. The main cause of damage to the large-diameter CMPs was found to be the large ground strains. Based on this unprecedented data set, the factors controlling the seismic performance of the 32 large-diameter CMPs were identified and framed into a pseudostatic analysis method for evaluating the response of large diameter flexible underground pipes subjected to ground strain. The proposed analysis, which is applicable to transient and permanent strains, is capable of describing the observed performance of large-diameter CMPs during the 1994 Northridge earthquake. It indicates that peak ground velocity is a more reliable parameter for analyzing pipe damage than is peak ground acceleration. Results of this field investigation and analysis are useful for the seismic design and strengthening of flexible buried conduits.

Davis, C.A.; Bardet, J.P.

2000-01-01

19

Swimming Performance of the Threatened Leopard Darter in Relation to Road Culverts  

Microsoft Academic Search

We investigated the relationship between swinming performance of the leopard darter Percinn pantherina evaluated in the laboratory and current velocities measured at the ends of corrugated-pipe and open-box culverts through road crossings. We tested leopard darters at each of six current velocities ranging from 0 to 60 cmls and measured burst frequency and distance. We uscd analysis of variance (ANOVA)

Conrad S. Toepfer; William L. Fisher; Jason A. Haubelt

1999-01-01

20

Surface impedance formalism for a metallic beam pipe with small corrugations  

NASA Astrophysics Data System (ADS)

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 ? and magnetic permeability ?. 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. They are also shown to be more accurate when compared to the earlier used analytical model.

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

2012-12-01

21

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

22

Measurements on tones generated in a corrugated flow pipe with special attention to the influence of a low frequency  

E-print Network

Measurements on tones generated in a corrugated flow pipe with special attention to the influence 2011. ISBN 978-82-8123-004-0., 2011. Summary It is well known that an air flow in a corrugated pipe with the pipe flow has later been presented by Goyder [3], Debut et al.[2], and Tonon et al. [7]. In a more

Paris-Sud XI, Université de

23

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, Güne?; Holten, Ad; Hirschberg, Avraham

2013-12-01

24

Swimming Performance of the Threatened Leopard Darter in Relation to Road Culverts  

Microsoft Academic Search

We investigated the relationship between swimming performance of the leopard darter Percina pantherina evaluated in the laboratory and current velocities measured at the ends of corrugated-pipe and open-box culverts through road crossings. We tested leopard darters at each of six current velocities ranging from 0 to 60 cm\\/s and measured burst frequency and distance. We used analysis of variance (ANOVA)

Conrad S. Toepfer; William L. Fisher; Jason A. Haubelt

1999-01-01

25

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

SciTech Connect

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 [Changzhou Key Laboratory of Sensor Networks and Environmental Sensing, College of IOT, Hohai University Changzhou, Jiangsu, 213022 (China)

2014-02-18

26

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

27

Response of reinforced concrete and corrugated steel pipes to surface load  

NASA Astrophysics Data System (ADS)

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

Lay, Geoff R.

28

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

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

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

29

Abandoned Wawona Road above Wawona Tunnel area. Note old culvert ...  

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

Abandoned Wawona Road above Wawona Tunnel area. Note old culvert pipe in foreground. Looking east-northeast - Wawona Road, Between South Entrance & Yosemite Valley, Yosemite Village, Mariposa County, CA

30

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

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

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

31

CORROSION RESISTANCE AND SERVICE LIFE OF DRAINAGE CULVERTS  

Microsoft Academic Search

16. Abstract Laboratory\\/yard tests and a field survey were conducted to determine how chloride-induced corrosion limits the durability of reinforced concrete culvert pipe, and to revise as needed Florida D.O.T. guidelines for predicting durability. Laboratory tests exposed culvert pipe segments from two different manufacturers to cyclic and continuous saltwater ponding for up to 4.4 years. Yard tests were conducted with

Alberto A. Sagüés; J. Peña; C. Cotrim; M. Pech-Canul

2001-01-01

32

Experimental Demonstration of Energy-Chirp Control in Relativistic Electron Bunches Using a Corrugated Pipe  

NASA Astrophysics Data System (ADS)

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.

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.

2014-01-01

33

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

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

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

34

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

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

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

35

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

36

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

USGS Publications Warehouse

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

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

2009-01-01

37

Sedimentation of MultiBarrel Culverts  

Microsoft Academic Search

Box culverts are generally designed to handle events with a 50 year return period and, therefore, most of the time they convey considerably lower flows. In many situations, water flow through a typical multi- barrel box culvert is relatively low throughout most of the year and usually concentrates in one barrel. A common adverse consequence for multi-barrel culverts when one

M. Muste

38

Criticality assessment of TRU burial ground culverts  

SciTech Connect

An effort to assess the criticality risks of {sup 239}Pu in TRU Burial Ground Culverts has been underway for several years. The concern arose from discrepancies in two types of monitors that have been used to assay the {sup 239}Pu waste prior to storage in 55-gallon drums that are placed in the culverts. One type is the solid waste monitor (SWM), which is based on gamma-ray measurements; the other is the neutron coincidence monitor, which is based on neutron measurements. The NCC was put into routine service after 1985 and has generally yielded higher 239 Pu assays than the SWM. Culverts with pre-1986 waste only had SWM assays of {sup 239}Pu; thus, it was questioned whether their actual {sup 239}Pu loadings could be high enough to pose criticality concerns. Studies to characterize the culvert criticality potential have included appraisal of NCC vs SWM, neutron measurements atop the culverts, gamma-ray measurements atop the culverts, and probabilistic risk analyses. Overall, these studies have implied that the culverts are critically safe; however, their results have not been examined collectively. The present report uses the collective information of the preceding studies to arrive at a more complete assessment of the culvert criticality aspects. A conservative k{sub eff} is estimated for an individual suspicious culvert and a PRA is evaluated for its {open_quotes}worst{close_quotes} drum. These two pieces of information form the basis of the appraisal, but other evidence is also included as support.

Winn, W.G.

1990-09-26

39

3. AERIAL VIEW OF SAW MILL RIVER CULVERT. NEPPERHAN AVENUE ...  

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

3. AERIAL VIEW OF SAW MILL RIVER CULVERT. NEPPERHAN AVENUE IS AT LEFT, SLIGHTLY FILLED SAW MILL RIVER CULVERT IS ON RIGHT. - Old Croton Aqueduct, Saw Mill River Culvert, Spanning Nepperhan Avenue, Yonkers, Westchester County, NY

40

CANDE-1980: Box culverts and soil models  

Microsoft Academic Search

The CANDE computer program, introduced in 1976 for the structural design and analysis of buried culverts, is extended and enhanced in this work effort to include options for automated finite element analysis of precast, reinforced concrete box culverts, and new nonlinear soil models. User input instructions for the new options, now operative in the CANDE-1980 program, are provided in the

M. G. Katona; P. D. Vittes; C. H. Lee; H. T. Ho

1981-01-01

41

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...

42

User's guide to the culvert analysis program  

USGS Publications Warehouse

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

Fulford, Janice M.

1995-01-01

43

Calapooia River Fish Passage Analysis and Culvert Removal Proposal  

E-print Network

Calapooia River Fish Passage Analysis and Culvert Removal Proposal Submitted to: Calapooia Watershed Council P.O. Box 844 Brownsville, OR 97327 Prepared by: Oregon State University Department ...................................................................................................... - 8 - Existing Culverts

Tullos, Desiree

44

71. Meadow Creek Culvert. This is an example of a ...  

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

71. Meadow Creek Culvert. This is an example of a triple arch concrete box culvert with stone facing mimicking rigid frame structures. - Blue Ridge Parkway, Between Shenandoah National Park & Great Smoky Mountains, Asheville, Buncombe County, NC

45

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

46

Experimental study on concrete box culverts in trenches  

Microsoft Academic Search

Concrete box culverts are widely used in expressways in mountain areas. Many problems frequently take place due to improperly\\u000a estimated vertical earth pressures on culverts. The prevailing Chinese General Code for Design of Highway Bridges and Culverts\\u000a (CGCDHBC) stipulates the computation of the design load on culverts primarily based on the linear earth pressure theory, which\\u000a cannot accurately describe the

Baoguo Chen; Junjie Zheng; Jie Han

2009-01-01

47

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

48

Birefringent corrugated waveguide  

DOEpatents

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

Moeller, Charles P. (Del Mar, CA)

1990-01-01

49

Development of gprs-based leak detection system for pipe pushing crossing part of nature gas pipeline  

Microsoft Academic Search

There would be a sealed space, called culvert box, between the nature gas pipeline and the concrete pipe when the nature gas pipeline crossing highways, railways and rivers using the trenchless pipe pushing technology. To deal with the problem of leak detection and monitoring for these culvert boxes, which were located in the field and scattered, a GPRS-based (GPRS: general

Fujun Liu; Shuai Kong; Zhangwei Ling; Mulin Zheng; Yueqiang Qian

2011-01-01

50

Sediment Transport through Road Culverts Retrofit for Fish Passage  

NASA Astrophysics Data System (ADS)

A critical component of watershed restoration includes improved mobility within the watershed for fish and other aquatic organisms. At the large scale, this effort includes installation of fish ladders around dams and at smaller scales replacement or retrofit of road culverts or installation of roughened channels to mitigate steep channel slopes. A project to quantify changes in culvert hydraulic performance and hydraulic capacity for three culvert shapes and six fish passage retrofit designs was initiated in June 2005. In 2007, laboratory physical model experiments were conducted to evaluate sediment transport and trapping characteristics of these designs over a range of flows. Generally, experimental results indicate trapped sediment in culverts retrofit to improve fish passage decreases the effectiveness of the retrofit due to sediment deposition in areas with lower velocities (where fish can rest). Other observations include: 1. Trapped sediment reduced the effective culvert barrel roughness and, thus, decreased water depths and increased velocities through the culvert, compared to clear water experiments with the retrofit baffles. 2. High flows (culvert barrel water depth/culvert height greater than 0.5) successfully cleared trapped sediment under conditions of minimal transport from upstream 3. Preliminary results indicate moderate flows (culvert barrel water depth/culvert height between 0.25 to 0.5) in combination with moderate sediment feed rates caused the greatest accumulation of trapped sediment These experiments highlight the importance of including sediment accumulation in design and analysis, and potentially impact design recommendations for culverts retrofit for fish passage and other similar fish passage improvement structures.

Lang, M.; Cashman, E.; Siegfried, L.; Smith, W. J.; Dillon, A.

2007-12-01

51

Earth pressures on reinforced concrete box culverts  

E-print Network

and correct any temperature effects on earth pressure readings. 3. Acquired a tractor-trailer rig capable of supplying four 12, 000- lb (53 kN) wheel loads on two 6-ft-( 1. 8 m) long tandem axles separated by 4 ft ( 1. 2 m). 4. Performed load tests... of the trailer, the culverts produced the wheel loads given in Fig. 7, The alternate axle configuration was obtained by a combination tractor-trailer truck that was provided by the Construction Equipment Training Division, TEES, TAHU . The dimensions...

Brown, Dale Evan

2012-06-07

52

Detail view of culvert headwall (no feature number assigned), from ...  

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

Detail view of culvert headwall (no feature number assigned), from the south side, looking north, near the west end of the project area. Culvert is located approximately 2000 feet east of Feature 2 - Beartooth Highway, Red Lodge, Montana to Cooke City, Montana, Cody, Park County, WY

53

Detail view of culvert headwall (no feature number assigned), from ...  

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

Detail view of culvert headwall (no feature number assigned), from the south side, looking north, near the west end of the project area. Culvert is located approximately 1000 feet east of Feature 1 - Beartooth Highway, Red Lodge, Montana to Cooke City, Montana, Cody, Park County, WY

54

Sediment Transport through Road Culverts Retrofit for Fish Passage  

Microsoft Academic Search

A critical component of watershed restoration includes improved mobility within the watershed for fish and other aquatic organisms. At the large scale, this effort includes installation of fish ladders around dams and at smaller scales replacement or retrofit of road culverts or installation of roughened channels to mitigate steep channel slopes. A project to quantify changes in culvert hydraulic performance

M. Lang; E. Cashman; L. Siegfried; W. J. Smith; A. Dillon

2007-01-01

55

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

56

Geo-Institute Graduate Student Organization student chapter at The University of Michigan is proud to present  

E-print Network

-span, deep-corrugated metal box culvert; and assess the long-term performance of buried polymer structures.g., pipes, culverts) and landfill geosynthetics (e.g., geomembranes, geosynthetic clay liners) using

Kamat, Vineet R.

57

Impedance of a Rectangular Beam Tube with Small Corrugations  

E-print Network

We consider the impedance of a structure with rectangular, periodic corrugations on two opposing sides of a rectangular beam tube. Using the method of field matching, we find the modes in such a structure. We then limit ourselves to the the case of small corrugations, but where the depth of corrugation is not small compared to the period. For such a structure we generate analytical approximate solutions for the wave number $k$, group velocity $v_g$, and loss factor $\\kappa$ for the lowest (the dominant) mode which, when compared with the results of the complete numerical solution, agreed well. We find: if $w\\sim a$, where $w$ is the beam pipe width and $a$ is the beam pipe half-height, then one mode dominates the impedance, with $k\\sim1/\\sqrt{w\\delta}$ ($\\delta$ is the depth of corrugation), $(1-v_g/c)\\sim\\delta$, and $\\kappa\\sim1/(aw)$, which (when replacing $w$ by $a$) is the same scaling as was found for small corrugations in a {\\it round} beam pipe. Our results disagree in an important way with a recent p...

Bane, Karl Leopold Freitag

2003-01-01

58

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

59

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

60

Evaluation of Factors Affecting Earth Pressures on Buried Box Culverts.  

E-print Network

??Factors affecting the earth pressures acting on buried box culverts under deep embankments were evaluated by field instrumentation and numerical analyses. Two instrumented cast-in-place concrete… (more)

Yang, Michael Zhiqiang

2000-01-01

61

160. DOUBLE BOX CULVERT AND PEDESTRIAN BRIDGE OVER DYKE MARSH ...  

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

160. DOUBLE BOX CULVERT AND PEDESTRIAN BRIDGE OVER DYKE MARSH LOOKING NORTHWEST. - George Washington Memorial Parkway, Along Potomac River from McLean to Mount Vernon, VA, Mount Vernon, Fairfax County, VA

62

93. View of two stonefaced concrete box culverts and retaining ...  

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

93. View of two stone-faced concrete box culverts and retaining wall along parkway. Facing east. - Blue Ridge Parkway, Between Shenandoah National Park & Great Smoky Mountains, Asheville, Buncombe County, NC

63

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

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

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

64

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

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

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

65

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

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

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

66

Detail view of Feature 3, culvert headwall, from the south ...  

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

Detail view of Feature 3, culvert headwall, from the south side, looking north, near the west end of the project area - Beartooth Highway, Red Lodge, Montana to Cooke City, Montana, Cody, Park County, WY

67

Detail view of Feature 2, culvert headwall, from the north ...  

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

Detail view of Feature 2, culvert headwall, from the north side, looking south, near the west end of the project area - Beartooth Highway, Red Lodge, Montana to Cooke City, Montana, Cody, Park County, WY

68

Detail view of Feature 1, culvert headwall, from the north ...  

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

Detail view of Feature 1, culvert headwall, from the north side, looking south, at the west end of the project area - Beartooth Highway, Red Lodge, Montana to Cooke City, Montana, Cody, Park County, WY

69

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

70

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

71

Fish Habitat Improvement in Box Culverts: Management in the Dark?  

Microsoft Academic Search

The effects of limestone baffles on the hydrological and fish assemblage characteristics of two separate 2.4-m-wide box culverts along the course of a cold headwater trout stream in southeastern Wisconsin were examined. Alternating limestone baffles were placed along the upstream half of one culvert, and the adjacent downstream half was left unmanipulated. The effects of the baffles on water depth,

Thomas M. Slawski; Timothy J. Ehlinger

1998-01-01

72

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

73

Corrugation crack front waves  

E-print Network

The paper presents a model of a dynamic crack with a wavy surface. So far, theoretical analysis of crack front waves has been performed only for in-plane perturbations of the crack front. In the present paper, generalisation is given to a more general three-dimensional perturbation, and equations that govern corrugation crack front waves are derived and analysed.

J. R. Willis; N. V. Movchan; A. B. Movchan

2012-06-05

74

Dealing with uncertainty when assessing fish passage through culvert road crossings  

USGS Publications Warehouse

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

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

2012-01-01

75

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 3 cm 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

76

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

77

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

78

Fish passage at selected culverts on the Hoonah Ranger District, Tongrass National Forest  

E-print Network

upstream. Class I culverts with the box plot charr upstreambox plot distribution and median number of juvenile coho salmon trapped was considerably greater downstream versus upstream of Class I culverts.box plot distribution and median of number of juvenile coho salmon trapped was considerably greater downstream versus upstream of Class I culverts.

Riley, Chris

2003-01-01

79

Shear Behavior and Mode of Failure for ASTM C1433 Precast Box Culverts  

Microsoft Academic Search

This study evaluates the shear behavior and capacity of the precast concrete box culverts subjected to HS 20 truck wheel load. The most critical culvert behavior was considered by studying culverts subjected to zero depth of the fill and placed on a rigid bedding material. Full-scale experimental tests, with wheel load placed at the distance d from the tip of

Ali Abolmaali; Anil Garg

2009-01-01

80

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 Dubé; Renaud Dostie; Pierre Bérubé

2008-01-01

81

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

82

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

83

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

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

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

84

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

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

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

85

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

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

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

86

220. View of the double concrete box culvert at Payne ...  

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

220. View of the double concrete box culvert at Payne Creek. Note that the stone facing is very similar to the model in photo NC-42-220. This is an example of a type 2 headwall. - Blue Ridge Parkway, Between Shenandoah National Park & Great Smoky Mountains, Asheville, Buncombe County, NC

87

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

88

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

89

Instability in pipe flow  

PubMed Central

The long-puzzling, unphysical result that linear stability analyses lead to no transition in pipe flow, even at infinite Reynolds number, is ascribed to the use of stick boundary conditions, because they ignore the amplitude variations associated with the roughness of the wall. Once that length scale is introduced (here, crudely, through a corrugated pipe), linear stability analyses lead to stable vortex formation at low Reynolds number above a finite amplitude of the corrugation and unsteady flow at a higher Reynolds number, where indications are that the vortex dislodges. Remarkably, extrapolation to infinite Reynolds number of both of these transitions leads to a finite and nearly identical value of the amplitude, implying that below this amplitude, the vortex cannot form because the wall is too smooth and, hence, stick boundary results prevail. PMID:18178623

Cotrell, D. L.; McFadden, G. B.; Alder, B. J.

2008-01-01

90

Model analysis of box culverts subjected to highway loading  

Microsoft Academic Search

The strain distribution and the deflections of reinforced-concrete box culverts associated with highway loading are determined\\u000a by testing scale models. Two types of scale models were constructured: 1\\/6-size concrete models and a 1\\/24-size photoelastic\\u000a model. The concrete models were instrumented with electric-resistance strain gages, and the deflections were measured with\\u000a dial indicators. Strain and deflection data due to live loading

G. R. Frederick; K. M. Tarhini

1989-01-01

91

Effect of Wheel Live Load on Shear Behavior of Precast Reinforced Concrete Box Culverts  

Microsoft Academic Search

This study reports on a part of a comprehensive study to evaluate the shear capacity of the precast reinforced concrete box culverts. Six full-scale 2.4 m 8f t span box culverts were tested to failure by subjecting each culvert to the AASHTO HS-20 wheel load. The location of the wheel load was varied from the tip of the haunch as

Ali Abolmaali; Anil K. Garg

2008-01-01

92

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

93

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

94

Aeroacoustics of the swinging corrugated tube: voice of the Dragon.  

PubMed

When one swings a short corrugated pipe segment around one's head, it produces a musically interesting whistling sound. As a musical toy it is called a "Hummer" and as a musical instrument, the "Voice of the Dragon." The fluid dynamics aspects of the instrument are addressed, corresponding to the sound generation mechanism. Velocity profile measurements reveal that the turbulent velocity profile developed in a corrugated pipe differs notably from the one of a smooth pipe. This velocity profile appears to have a crucial effect both on the non-dimensional whistling frequency (Strouhal number) and on the amplitude of the pressure fluctuations. Using a numerical model based on incompressible flow simulations and vortex sound theory, excellent predictions of the whistling Strouhal numbers are achieved. The model does not provide an accurate prediction of the amplitude. In the second part of the paper the sound radiation from a Hummer is discussed. The acoustic measurements obtained in a semi-anechoic chamber are compared with a theoretical radiation model. Globally the instrument behaves as a rotating (Leslie) horn. The effects of Doppler shift, wall reflections, bending of the tube, non-constant rotational speed on the observed frequency, and amplitude are discussed. PMID:22280698

Nakibo?lu, Güne?; Rudenko, Oleksii; Hirschberg, Avraham

2012-01-01

95

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

Code of Federal Regulations, 2012 CFR

...false Roadway, tunnels and subways, bridges and culverts, ties, rails, other track material, ballast, track laying and...15 Roadway, tunnels and subways, bridges and culverts, ties, rails, other track material, ballast, track laying...

2012-10-01

96

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

Code of Federal Regulations, 2013 CFR

...false Roadway, tunnels and subways, bridges and culverts, ties, rails, other track material, ballast, track laying and...15 Roadway, tunnels and subways, bridges and culverts, ties, rails, other track material, ballast, track laying...

2013-10-01

97

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

Code of Federal Regulations, 2010 CFR

...false Roadway, tunnels and subways, bridges and culverts, ties, rails, other track material, ballast, track laying and...15 Roadway, tunnels and subways, bridges and culverts, ties, rails, other track material, ballast, track laying...

2010-10-01

98

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

Code of Federal Regulations, 2011 CFR

...false Roadway, tunnels and subways, bridges and culverts, ties, rails, other track material, ballast, track laying and...15 Roadway, tunnels and subways, bridges and culverts, ties, rails, other track material, ballast, track laying...

2011-10-01

99

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

Code of Federal Regulations, 2014 CFR

...Roadway, tunnels and subways, bridges and culverts, ties, rails, other track material, ballast, track laying and surfacing...Roadway, tunnels and subways, bridges and culverts, ties, rails, other track material, ballast, track laying and...

2014-10-01

100

Finite-Element Modeling and Analysis of Reinforced Concrete Box Culverts  

Microsoft Academic Search

There have been several controversies with regard to the true behavior of reinforced concrete box culverts in recent years. To be able to conduct a parametric study to develop design equations, a complete three-dimensional verified finite-element model of culverts is essential. This study presents the development of an analytical program to investigate the shear capacity of precast reinforced concrete box

Anil K. Garg; Ali Abolmaali

2009-01-01

101

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

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

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

102

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

E-print Network

flow for westslope cutthroat trout Oncorhynchus clarkii lewisi and brook trout Salvelinus fontinalis and downstream of 23 culverts revealed little differences in westslope cutthroat trout or brook trout above for juvenile and adult westslope cutthroat trout and brook trout during the summer indicates that culvert

McMahon, Thomas E.

103

Juvenile Coho Salmon Leaping Ability and Behavior in an Experimental Culvert Test Bed  

Microsoft Academic Search

As part of a research program aimed at identifying the culvert configurations and associated hydraulic conditions that foster the successful upstream movement of juvenile salmon, we investigated the ability of hatchery-raised juvenile coho salmon Oncorhynchus kisutch to leap into an experimental culvert under varying hydraulic conditions. Five outfall drops ranging from 0 to 32 cm were tested to represent differing

Robert P. Mueller; Susan S. Southard; Christopher W. May; Walter H. Pearson; Valerie I. Cullinan

2008-01-01

104

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

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

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

105

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...

106

Measurement of earth pressures on concrete box culverts under highway embankments  

SciTech Connect

To obtain a better understanding of the stresses acting on cast-in-place concrete box culverts, and to investigate the conditions which resulted in a culvert failure under about 12 meters of backfill, two sections of a new culvert were instrumented. The measured earth pressure distribution was found to depend upon the height of the embankment over the culvert. For low embankment heights (less than one-half the culvert width), the average measured vertical earth pressures, weighted by tributary length, were about 30% greater than the recommended AASHTO pressures. The measured lateral pressures were slightly greater than the AASHTO pressures. As the embankment height increased, the measured weighted average vertical stress exceeded the AASHTO pressures by about 20%. Lateral pressures which exceeded the vertical pressures were recorded at the bottom of the culvert walls, and small lateral pressures were recorded on the upper locations of the wall. The high lateral pressures at the base of the wall are consistent with the results from finite element analyses with high density (modulus) backfill material placed around the culvert.

Yang, M.Z.; Drumm, E.C.; Bennett, R.M.; Mauldon, M.

1999-07-01

107

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

108

Corrugated Membrane Fuel Cell Structures  

SciTech Connect

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

Grot, Stephen [President, Ion Power Inc.] President, Ion Power Inc.

2013-09-30

109

Intensified membrane filtration with corrugated membranes  

Microsoft Academic Search

Crossflow membrane microfiltration of 30% (w\\/w) water-in-oil emulsions is reported using hydrophobic PVDF and PTFE membranes. The flux performance of corrugated membranes is compared with that of flat membranes. The influence of crossflow velocity (CFV), flow channel height and transmembrane pressure (TMP) were investigated. The effect of varying the angle of corrugation (between the flow direction and the corrugation) on

K Scott; A. J Mahmood; R. J Jachuck; B Hu

2000-01-01

110

Instrumentation for monitoring buried pipe behavior during backfilling  

SciTech Connect

An extensive instrumentation plan was devised to monitor buried pipe behavior, soil behavior and pipe-soil interaction during backfilling. The emphasis of the instrumentation plan was to monitor these parameters under different installation techniques without impeding construction operations. Different types and sizes of pipe were selected for installation in trenches excavated in undisturbed in situ soil conditions. Installation variables included in situ soil conditions, trench widths, backfill material (including controlled low strength material), haunching effort, and compaction methods. A total of fourteen tests, each including reinforced concrete, corrugated steel, and corrugated HDPE, were conducted. Eleven of the installations were conducted with 900 mm inside diameter pipe and three with 1,500 mm inside diameter pipe. The pipes were buried to a cover depth of 1.2 m. Measurements of pipe shape, pipe strains, pipe-soil interface pressures, soil density, soil stresses, and soil strains were collected. Pipe shape changes were measured by a custom built profilometer. Custom designed bending beam pressure transducers were used in the steel pipe to measure interface pressures. Most of the instrumentation performed well and measured results were within the range expected. Pipe-soil interaction effects were effectively measured with the instruments selected. Pipe shape changes were a very valuable parameter for investigating pipe-soil interaction.

McGrath, T.J.; Selig, E.T.; Webb, M.C.

1999-07-01

111

Innovative High-Gain Corrugated Horn Antenna Combining Horizontal and Vertical Corrugations  

Microsoft Academic Search

An innovative kind of corrugated horn antenna is proposed within this letter, the profile of the horn is based on the combination of horizontal and vertical corrugations. The main advantage of these profiles is the possibility of combining high-gain with short profiles, meanwhile keeping the main performances of the conventional corrugated horns. Besides, this horn results in an easier manufacture

Jorge Teniente; Ramón Gonzalo; C. Del-Rio

2006-01-01

112

Experimental Investigation of Shear Capacity of Precast Reinforced Concrete Box Culverts  

Microsoft Academic Search

This study presents an experimental program to investigate the shear capacity of precast reinforced concrete box culverts. Each culvert was subjected to monotonically increasing load through a 254 mm508 mm 10 in.20 in. load plate in order to simulate the HS20 truckload per AASHTO 2005. Instrumentation included strain gauges, high-resolution laser deflection sensor, and automated data acquisition. Four tests were

Anil K. Garg; Ali Abolmaali; Raul Fernandez

2007-01-01

113

Application of a Multistate Model to Estimate Culvert Effects on Movement of Small Fishes  

Microsoft Academic Search

While it is widely acknowledged that culverted road-stream crossings may impede fish passage, effects of culverts on movement of nongame and small-bodied fishes have not been extensively studied and studies generally have not accounted for spatial variation in capture probabilities. We estimated probabilities for upstream and downstream movement of small (30-120 mm standard length) benthic and water column fishes across

James R. Norman; Megan M. Hagler; Mary C. Freeman; Byron J. Freeman

2009-01-01

114

Experimental investigation on discharge coefficient for a combined broad crested weir-box culvert structure  

NASA Astrophysics Data System (ADS)

This study investigates the hydraulic characteristics of simultaneous flow over broad crested weir and through box (square) culverts experimentally. The variation of discharge coefficient (Cd) of the combined structure with various affective parameters such as upstream head, length of culvert, culvert inlet shape, culvert internal dimension, weir crest height, weir side slope angle, and weir width was analyzed. For this purpose 12 glass models of combined broad crested weirs and box culverts were manufactured and tested in a laboratory flume of 12 m. Discharge coefficient predicting equations were developed as a function of the dimensionless terms. The overall results showed that Cd increases as the ratio of the total head of water above the weir crest to the height of the weir crest H/P increases for all the models and for each flow state (weir and combined). Cd values increased as the head increased for all the models tested as culvert flow only, and also with decreasing of the angle between crest of the weir with the sides.

Guven, A.; Hassan, M.; Sabir, Shahin

2013-09-01

115

Corrugated Limiting Tab for Jet Mixing  

NASA Astrophysics Data System (ADS)

The mixing promoting efficiency of a limiting corrugated tab, located across a diameter of Mach 1.73 convergent-divergent circular nozzle exit, has been studied experimentally. With uncorrugated tab the core length reduction achieved is just 42%, but for the tab with semi-circular corrugations, the reduction in core length is as high as 98%, at underexpanded level corresponding to NPR 6. The corrugation geometries have a strong effect on the mixing promoting capability of the tab. The mixing promotion is found to be the best when there is no pressure gradient at the nozzle exit. Among the corrugated tabs studied, the tab with semi-circular corrugations is found to be the best mixing promoter. The core length reduction achieved for the correctly expanded jet with the tab with semi-circular corrugations is almost 98%, whereas the reduction caused by the tabs with triangular and rectangular corrugations are 96% and 92%, respectively. In addition to reducing the core length the corrugated tabs were found to be weakening the waves and shortening the shock cells length.

Kaushik, Mrinal; Rathakrishnan, E.

2013-12-01

116

Heat transfer optimization in corrugated wall channels  

Microsoft Academic Search

In this work, the heat transfer in a channel composed of a smooth and a corrugated wall is studied under laminar flow conditions. The velocity and temperature distributions are determined with the help of a finite element model. The heat transfer performance of the corrugated wall channel is compared with that of a smooth wall duct. The numerical model is

Giampietro Fabbri

2000-01-01

117

Characterization of corrugated waveguides by modal analysis  

Microsoft Academic Search

A general formulation for the characterization of corrugated waveguides is presented. The formulation is based on modal expansion in the different smooth-walled waveguides which constitute the corrugated structure and on the use of mode matching at discontinuities. The use of an admittance matrix formulation and a suitable root-finding algorithm leads to a rigorous and efficient technique. Dispersion curves are presented

Jaime Esteban; JesGs M. Rebollar

1991-01-01

118

Mechanical Analysis of Trapezoidal Corrugated Composite Skins  

NASA Astrophysics Data System (ADS)

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

Ghabezi, P.; Golzar, M.

2013-08-01

119

Elastic wave propagation in sinusoidally corrugated waveguides.  

PubMed

The ultrasonic wave propagation in sinusoidally corrugated waveguides is studied in this paper. Periodically corrugated waveguides are gaining popularity in the field of vibration control and for designing structures with desired acoustic band gaps. Currently only numerical method (Boundary Element Method or Finite Element Method) based packages (e.g., PZFlex) are in principle capable of modeling ultrasonic fields in complex structures with rapid change of curvatures at the interfaces and boundaries but no analyses have been reported. However, the packages are very CPU intensive; it requires a huge amount of computation memory and time for its execution. In this paper a new semi-analytical technique called Distributed Point Source Method (DPSM) is used to model the ultrasonic field in sinusoidally corrugated waveguides immersed in water where the interface curvature changes rapidly. DPSM results are compared with analytical solutions. It is found that when a narrow ultrasonic beam hits the corrugation peaks at an angle, the wave propagates in the backward direction in waveguides with high corrugation depth. However, in waveguides with small corrugation the wave propagates in the forward direction. The forward and backward propagation phenomenon is found to be independent of the signal frequency and depends on the degree of corrugation. PMID:16642814

Banerjee, Sourav; Kundu, Tribikram

2006-04-01

120

Truss-core corrugation for compressive loads  

NASA Technical Reports Server (NTRS)

A corrugated panel structure for supporting compressive loads is described which includes curved cap strips separated by truss-core web segments. The truss-core web segments are formed from first and second flat panels with a corrugated filler in between them. The corrugated filler extends in the direction of the compressive load. As a result, all components of the panel structure have a compressive load carrying capability resulting in a high strength-to-weight ratio when the compressive load is limiting. Application to rocket and aircraft structures is suggested.

Davis, Randall C. (inventor); Jackson, Robert (inventor)

1988-01-01

121

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

SciTech Connect

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

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

1989-08-15

122

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 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, Jack R. (Oak Ridge, TN); Curtis, Charles H. (Kingston, TN)

1983-01-01

123

Evolutionary design of corrugated horn antennas  

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

124

Pattern analysis of corrugated horn antennas  

Microsoft Academic Search

The corrugated horn has been established as an antenna with low sidelobes and backlobes, rotationally symmetric patterns (for square pyramidal and conical horn shapes), and broad-band performance [1]-[9]. These properties make this horn useful for many applications. Previous studies have used conventional aperture integration techniques to evaluate the patterns of the corrugated horn. In general, the near axisE-plane radiation pattern

CARL A. MENTZER; L. Peters Jr.

1976-01-01

125

PVDF corrugated transducer for ultrasonic ranging sensor  

Microsoft Academic Search

This paper describes a method to design and build ultrasonic transceivers using low-cost polyvinylidene fluoride (PVDF) corrugated film. The corrugated transducer features multiple curved sections, which provide a higher acoustic output compared to traditional ultrasonic transducer design using a single curved PVDF film section. We have built and demonstrated a prototype 200kHz transducer and found it to be practical for

Minoru Toda; Jerry Dahl

2007-01-01

126

Skateboarding in a Culvert First, consider a bead of mass m that is sliding, without friction, on a stiff wire. It is  

E-print Network

Skateboarding in a Culvert First, consider a bead of mass m that is sliding, without friction) + mg^ · ^N (W) c Joel Feldman. 2013. All rights reserved. January 18, 2013 Skateboarding in a Culvert 1 case of a skateboarder inside a circular culvert of radius a. Let's put the bottom of the circle

Feldman, Joel

127

NUMERICAL MODELING OF UNSTEADY FLOW AROUND A BOX CULVERT AND ITS VERIFICATION  

NASA Astrophysics Data System (ADS)

This paper deals with a numerical model to simulate flow through a box culvert, which represents flow during flash floods under highways in Oman. We firstly show the typical flow patterns with the transition from free surface flows to pressurized flows and overflows over a culvert, based on hydraulic experiments. Then, a numerical model applicable to the full/partial full pressurized flows is tested to simulate the typical flow patterns under the conditions of experiments.It is pointed out that although the numerical model used here can simulate the simple flow patterns to some extents, the model should be improved further to get better results.

Saif, Alhinai; Hosoda, Takashi; Shirai, Hidekazu

128

Effects of corrugation parameters on fluid mixing characteristics in corrugated passages  

NASA Astrophysics Data System (ADS)

Static mixers are well established in process engineering. Their particular advantages are in-line mixing, no moving parts, low power consumption, and simultaneous homogenization of residence time behavior. Several species of static mixers are well known. An example of their arrangement is based on corrugated passages formed by layers of single plates with opposing orientation. Until now, the corrugation parameters of this species have mainly been designed according to few experimental studies. However, flow phenomena, implied by the geometry of the corrugated structure, are of significant influence on the mixing behavior, the pressure drop, and the residence time characteristics in corrugated passages. In new investigations, the effects of a variety of corrugation parameters on flow phenomena, mixing characteristics/and pressure drop have been systematically determined. The results prove that there are quite different kinds of flow phenomena depending on the geometrical parameters of the structure. Some parameter combinations lead to no mixing at all, others lead to a homogeneous mixing within a small length. Examples are shown of flow behavior in corrugated passages; here the flow has been traced locally making the flow direction evident. The effects of corrugation parameters on the fundamental flow phenomena will be discussed. In order to describe and predict the flow behavior in these corrugated passages, a model has been set up based on the fundamental flow phenomena. This model allows the simulation of flow behavior in corrugated passages, thereby allowing, also, the simulation of the mixing characteristics and the residence time behavior of the fluid in these structures. Examples of the simulation, where the local addition of a tracer and its mixing across the structure has been simulated, are shown. Further results of flow simulation on mixing characteristics and dynamic aspects will be compared to experiments. Combined with the pressure drop in corrugated passages, the model allows the optimization of motionless mixer design. Several aspects of structure optimization will be discussed.

Gaiser, Gerd; Kottke, Volker

1991-05-01

129

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

130

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

131

Culvert Design for Flood Routing considering Sediment Transport W.J. Rahmeyer PhD.1  

E-print Network

UNITED STATES OF AMERICA E-mail: william.rahmeyer@usu.edu 2 Department of Engineering and Technology that sediment is transported in suspension with little effect on the flow capacity of the culverts. However suspension. Bed-load transport of sediment can reduce effective flow areas, reduce flow capacity, increase

Rahmeyer, William J.

132

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

NASA Astrophysics Data System (ADS)

*Aziz, A A aabdulaziz@uh.edu Allied Geophysical Lab, Department of Earth and Atmospheric Sciences, University of Houston, TX, USA Stewart, R R rrstewart@uh.edu Allied Geophysical Lab, Department of Earth and Atmospheric Sciences, University of Houston, TX, USA *Green, S L slgreen@yahoo.com Allied Geophysical Lab, Department of Earth and Atmospheric Sciences, University of Houston, TX, USA A 3D ground penetrating radar (GPR) survey, using three different frequency antennae, was undertaken to image buried steel culverts at the University of Houston's La Marque Geophysical Observatory 30 miles south of Houston, Texas. The four culverts, under study, support a road crossing one of the area's bayous. A 32 m by 4.5 m survey grid was designed on the road above the culverts and data were collected with 100 MHz, 250 MHz, and 1 GHz antennae. We used an orthogonal acquisition geometry for the three surveys. Inline sampling was from 1.0 cm to 10 cm (from 1 GHz to 100 MHz antenna) with inline and crossline spacings ranging from 0.2 m to 0.5 m. We used an initial velocity of 0.1 m/ns (from previous CMP work at the site) for the display purposes. The main objective of the study was to analyze the effect of different frequency antennae on the resultant GPR images. We are also interested in the accuracy and resolution of the various images, in addition to developing an optimal processing flow.The data were initially processed with standard steps that included gain enhancement, dewow and temporal-filtering, background suppression, and 2D migration. Various radar velocities were used in the 2D migration and ultimately 0.12 m/ns was used. The data are complicated by multipathing from the surface and between culverts (from modeling). Some of this is ameliorated via deconvolution. The top of each of the four culverts was evident in the GPR images acquired with the 250 MHz and 100 MHz antennas. For 1 GHz, the top of the culvert was not clear due to the signal's attenuation. The 250 MHz shielded antenna provides a vertical resolution of about 0.1 m and is the choice to image the culverts. The 100 MHz antenna provided an increment in depth of penetration, but at the expense of a substantially diminished resolution (0.25 m).

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

2013-12-01

133

Graphene plasmon propagation on corrugated silicon substrates.  

PubMed

The scheme of graphene on a silicon substrate is potentially compatible to the microelectronic technology. But the maintained plasmons have considerable ohmic loss because of silicon's large permittivity. We introduce air grooves in the silicon surface to reduce the optical thickness of substrate and hence decrease the propagation loss. The properties of graphene plasmons on the corrugated substrates are numerically investigated, in terms of the photon frequency and the geometrical parameters of the corrugated layer, considering both ohmic loss and scattering loss. The plasmons propagation lengths for the corrugated substrates can exceed twice of those for flat silicon in a broadband in mid-infrared. This study may be useful for designing of compact mid-infrared waveguides based on graphene for future photonic integrated circuits. PMID:25531593

Kong, Xiang-Tian; Bai, Bing; Dai, Qing

2015-01-01

134

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

135

CONTRIBUTION TO THE MODELLING OF THE CORRUGATED CARDBOARD BEHAVIOUR  

E-print Network

CONTRIBUTION 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 considering the corrugated cardboard as an orthotropic material is developed. This approach permits after

Boyer, Edmond

136

STUDY OF THE HYGRO-MECHANICAL BEHAVIOR OF CORRUGATED CARDBOARD  

E-print Network

STUDY OF THE HYGRO-MECHANICAL BEHAVIOR OF CORRUGATED CARDBOARD Samir Allaoui1 , Zoheir Aboura2 Tremblays-en-France, France Abstract Corrugated cardboard is very sensitive to atmospheric conditions), on the mechanical behavior of corrugated cardboard sandwich struc- ture. Tensile and three-point bending tests were

Paris-Sud XI, Université de

137

Elastic behavior of corrugated cardboard: experiments and modeling  

Microsoft Academic Search

Motivated by computed homogeneous of linear corrugated cardboard behavior, an analytical model related to the assessment of equals behavior is proposed. This model takes into account the geometrical and mechanical properties of the corrugated cardboard constituents. An experimental methodology is also proposed to obtain both the in-plane elastic properties of each constituents and the corrugated cardboard. After model validation by

Z. Aboura; N. Talbi; S. Allaoui; M. L. Benzeggagh

2004-01-01

138

Surface-corrugated microfiber Bragg grating  

NASA Astrophysics Data System (ADS)

There are two steps to obtain as small as possible fiber Bragg gratings. First, it is to taper the fiber and reduce its diameter. A subwavelength-scale microfiber (MF) is the basic element of miniature fiber devices and sub-systems. Then it is to reduce the grating length. For short fiber grating, strong refractive index modulations are necessary. Strong refractive index modulations can be obtained inducing surface corrugation by alternating layers of different materials, one of which can be air. Several techniques have been proposed for the fabrication of surface-corrugated fiber gratings, including photorefractive inscription using etching, femtosecond lasers, and focused ion beam (FIB). So far, FIB is the most flexible and powerful tool for patterning, cross- sectioning or functionalizing a subwavelength circular MF due to its small and controllable spot size and high beam current density. In past two years, a number of ultra-compact surface corrugated microfiber Bragg gratings (SCMGs) have been successfully fabricated by FIB milling. The length of FIB milled SCGMs can be as small as tens of micrometers. In addition, there are several novel proposals on SCMG including wrapping a microfiber on a microstructure rod or put a microfiber on a surface-corrugated planar grating. In this paper, we will introduce recent advances in these ultra-small SCMGs and their characteristics and applications.

Xu, Fei; Kou, Jun-Long; Luo, Wei; Lu, Yan-qing

2012-11-01

139

Upward flame spread over corrugated cardboard  

Microsoft Academic Search

As part of a study of the combustion of boxes of commodities, rates of upward flame spread during early-stage burning were observed during experiments on wide samples of corrugated cardboard. The rate of spread of the flame front, defined by the burning pyrolysis region, was determined by visually averaging the pyrolysis front position across the fuel surface. The resulting best

M. J. Gollner; F. A. Williams; A. S. Rangwala

2011-01-01

140

Operating experience firing waxed corrugated cardboard waste  

SciTech Connect

Georgia-Pacific operates a corrugated packaging facility in Doraville, Georgia which a suburb of Atlanta. The plant processes bulk brown paper into corrugated sheets for corrugated packaging. The plant`s process and building heat requires approximately 15,000 PPH steam at 150 psig which was supplied by a natural gas fired package boiler. The mill disposed of the cardboard trimmings and waste in a nearby landfill at a disposal cost of several thousand dollars per month. In 1992, the mill recognized that the landfill would close in several years which would result in a significant increase in monthly cardboard waste disposal costs. Therefore, the mill sought an alternate yet economical solution for waste disposal. After evaluating several different alternatives including recycling, the mill installed a boiler system designed to fire the waxed corrugated cardboard waste (WCW) as both a solution for disposal of this waste and as an alternate source of boiler fuel. This paper reviews plant design, operating performance and maintenance history.

McBurney, B.

1995-09-01

141

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

142

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

143

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

144

Performance of corrugated quantum well infrared photodetectors  

NASA Astrophysics Data System (ADS)

Corrugated quantum well infrared photodetectors (C-QWIPs) use total internal reflection to couple normal incident light into the detectors. In this work, we report the performance of C- QWIPs at different wavelengths. Compared with 45 degrees edge coupling, a C-QWIP increases the background photocurrent to dark current ratio r(subscript I) by a factor between 2.4 and 4.4, thereby increasing the background-limited temperature by 3 to 5 K. The detectivity D* is increased by a factor of 2.4. We applied the C-QWIP to two-color detection and obtained precision thermometric measurements. We have also fabricated and characterized a 256 X 256 C-QWIP array with cutoff wavelength at 11.2 micrometer. The uncorrected nonuniformity ((sigma) /mean) in the central 128 X 128 subarray is 2.3%. The NE(Delta) T at 63 K is estimated to be 23 mK. Furthermore, we have shown that r(subscript I) can be further increased by fabrication of the C-QWIP into the corrugated hot-electron transistor structure. The enhanced performance of the corrugated structure, combined with its simple processing steps, greatly improves the QWIP technology.

Choi, Kwong K.; Chen, C. J.; Goldberg, Arnold C.; Chang, W. H.; Tsui, Daniel C.

1998-07-01

145

Corrugated Membrane Fuel Cell 2010 DOE Hydrogen Program Fuel Cell  

E-print Network

Due (Month/Yr) 1 1.1 50 cm2 jig designed and built 411 2 1.2 Both flat and corrugated seals for 50 cm2 jig 7 force 5/12 5 3 Provide method for making metal corrugated GDL plate subassemblies, with resistance mOhm-cm2 and >20 psi, p compressive force 5/125/12 6 3 Down-select most promising metal corrugated

146

Piping Plover  

USGS Multimedia Gallery

Chicks and eggs of piping plovers. The piping plover is a small migratory shorebird listed as endangered in Canada and the U.S. Great Lakes, and threatened throughout the remainder of its U.S. breeding and winter range. Recent surveys indicate that there are only about 8,000 adults in existence.  Th...

2010-02-24

147

Piping Plover  

USGS Multimedia Gallery

An adult piping plover. The piping plover is a small migratory shorebird listed as endangered in Canada and the U.S. Great Lakes, and threatened throughout the remainder of its U.S. breeding and winter range. Recent surveys indicate that there are only about 8,000 adults in existence. The USGS is co...

2010-02-24

148

Fabrication and simulation of corrugated long period microfiber gratings  

NASA Astrophysics Data System (ADS)

A corrugated long period microfiber grating (C-LPMFG) is fabricated by etching the corrugated LPFG down to tens of micrometers in diameter with corrugated periodic structures made by using imprint lithography. It can be a grating because of the periodic effective index difference caused by the corrugated structures without prestrain. During etching of C-LPMFGs the in-situ monitoring of resonant wavelength shows that the wavelength shift varies rapidly with the etching of fiber. The resonant dips are calculated and have similar trends compared with the experiment data. The C-LPMFG is used as a temperature sensor with sensitivity of -146 pm/°C.

Wang, Hsiao-Yuh; Chuo, Shih-Min; Wang, Lon A.

2011-05-01

149

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

150

The corrugated horn as an antenna range standard.  

NASA Technical Reports Server (NTRS)

The corrugated horn is discussed as is a valuable tool for use in microwave pattern ranges. It has the properties of concentrated energy in the main beam, low backlobes, high efficiency, almost monotonic amplitude, and phase radiation patterns which make the corrugated horn useful for a source antenna in a pattern range and also as a possible standard antenna for calibration purposes.

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

1973-01-01

151

SPM measurements of graphene corrugation and spatial correlation  

Microsoft Academic Search

In order to determine the effect of graphene corrugation on electronic transport, it is most important to know the spatial correlation properties of the corrugated graphene structure. In spite of much experimental effort, there is still contentious debate about the structure of graphene, both in supported and suspended geometries. It has frequently been asserted that a graphene monolayer exfoliated onto

William Cullen; Jianhao Chen; Masa Ishigami; Ellen Williams; Michael Fuhrer

2009-01-01

152

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

153

Origin of Anomalous Corrugation Height of STM Images of Graphite  

Microsoft Academic Search

To clarify the origin of the anomalous corrugation height of STM images of a graphite under a constant current mode, we carefully investigated the variation of the tunneling current and forces between the lever and graphite during lateral scans. In the case of an unoxidized Pt lever, the variations of the sample displacement, the lever deflections and the apparent corrugation

Yasuhiro Sugawara; Tatsuya Ishizaka; Seizo Morita

1990-01-01

154

Elastic behavior of corrugated cardboard: Experiments and Modeling Z. ABOURAa *  

E-print Network

1 Elastic behavior of corrugated cardboard: Experiments and Modeling Z. ABOURAa * , N. TALBIb , S cardboard behavior, an analytical model related to the assessment of equals behavior is proposed. This model takes into account the geometrical and mechanical properties of the corrugated cardboard constituents

Paris-Sud XI, Université de

155

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; Hänggi, P

2011-12-01

156

Corrugation Profile for the Quasioptical Polarization Separator  

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

157

Comparison of test results for flat plate, transpired flat plate, corrugated, and transpired corrugated solar air heaters  

NASA Astrophysics Data System (ADS)

Results from tests to demonstrate technical improvements from transpiring and/or corrugating a selective black absorber plate solar air collector are reported. A literature review is presented, and the specific working components of transpired and nontranspired flat and corrugated absorbers are provided, including transpiration through slots, a microperforated plate, a corrugated plate, and a transpired, slotted, corrugated plate. Inlet and outlet temperatures were monitored, and inlet air was controlled, with trials covering temperatures of 38, 60, 82, and 104 C to test the effect of maintaining the fluid temperature close to the collector temperature. No differences were observed in running the collectors with corrugations vertically instead of horizontally, and the collector with transpiration through slots was found to display the lowest pressure drop.

Rhee, S. J.; Edwards, D. K.

1981-11-01

158

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

159

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

E-print Network

with a corrugated brass plate, SSW was suggested as a possi- ble cause for the backward beam displacement effectScholte-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

Boyer, Edmond

160

Single and dual-band multimode hard horn antennas with partly corrugated walls  

Microsoft Academic Search

We introduce a partly corrugated hard horn, consisting of a smooth-walled horn with an attached longitudinally corrugated outer section. This alleviates the problems with the manufacturing when the longitudinal corrugations extend into the throat of the horn. The transition between the inner smooth walled part and the outer corrugated part is abrupt. This is used and controlled to design better

Omid Sotoudeh; Per-Simon Kildal; Per Ingvarson; Sergei P. Skobelev

2006-01-01

161

Effectiveness of a barrier wall and culverts in reducing wildlife mortality on a heavily traveled highway in Florida  

Microsoft Academic Search

Because of high numbers of animals killed on Paynes Prairie State Preserve, Alachua County, Florida, the Florida Department of Transportation constructed a barrier wall-culvert system to reduce wildlife mortality yet allow for passage of some animals across the highway. During a one year study following construction, we counted only 158 animals, excluding hylid treefrogs, killed in the same area where

C. Kenneth Dodd Jr; William J. Barichivich; Lora L. Smith

2004-01-01

162

Proceedings of the South Dakota Academy of Science,Vol. 83 (2004) 125 ROAD CULVERTS ACROSS STREAMS  

E-print Network

WITH THE ENDANGERED TOPEKA SHINER, NOTROPIS TOPEKA, IN THE JAMES, VERMILLION, AND BIG SIOUX RIVER BASINS. Steven S stream habitat. Keywords Stream, culvert, Topeka shiner, Notropis topeka, road crossings, barriers- vert to the stream (Gebhards and Fisher 1972). The listing of the Topeka shiner (Notropis topeka

163

An Evaluation of the Use of Critical Swimming Speed for Determination of Culvert Water Velocity Criteria for Smallmouth Bass  

Microsoft Academic Search

Critical swimming speed (Ucrit) is a common measure of the relationship between exercise intensity and duration within the prolonged performance envelope. This relationship is often used to establish water velocity criteria for fishways and culverts; however, the technique involves the assumptions that fish will choose to move at (1) a swimming speed equivalent to Ucrit and (2) a ground speed

Stephan Peake

2004-01-01

164

Effective Thermal Conductivity of Corrugated Insulating Materials  

NASA Astrophysics Data System (ADS)

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

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

165

Fatigue testing of corrugated and Teflon hoses  

NASA Technical Reports Server (NTRS)

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

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

1990-01-01

166

Surface corrugations influence monolayer graphene electromagnetic response  

NASA Astrophysics Data System (ADS)

We consider the corrugated monolayer graphene membrane electromagnetic response in terahertz range. We study the generated in irradiated graphene total current (from both valleys) taking into account for the first time both the synthetic electric fields arising due to the (inevitable) presence in graphene of inherent out-of-plane nanodeformations and the double-valleys energy spectrum of Dirac charge particles. Our approach is based on atomistic quantum mechanics used for the description of (1) the valence ?-? bonds changes generated by activating external periodic electric field and also (2) the mechanism of Dirac electron interaction with this time-dependent perturbation. We consider the problem in the framework of the model of noninteracting Dirac electrons. Assuming surface corrugations not to be very rough we obtain for weak fields the formula for the total current induced in graphene membrane. Our formula describes the curved current paths in the linear in E(t) approximation for the given graphene surface form. We show that the local direction of current paths is determined by the synthetic electric field whose direction may essentially differ from the one of the external field and depends on the local curvature of the graphene membrane. We also demonstrate that valley currents generated by a linearly external field have nonzero elliptic polarization angles depending on the point (x,y). Valley currents are shown to rotate in opposite directions in different valleys. The results obtained below can be applied to the analysis of different devices in terahertz optics and optoelectronics and the imaging experiments at the Dirac point.

Firsov, Yu. A.; Firsova, N. E.

2014-08-01

167

Designs and applications of corrugated QWIPs  

NASA Astrophysics Data System (ADS)

In this paper, we will describe the performance of two long wavelength 1024 × 1024 corrugated quantum well infrared photodetector focal plane arrays (C-QWIP FPAs) with cutoff wavelengths at 8.6 and 9.0 ?m, respectively. The FPAs are background limited (BLIP) at around 76 K in an f/1.8 optical system. In addition to the high performance of these C-QWIPs, the corresponding FPAs are also easily producible, making them ideal for large production. We will discuss the optimization of the detectors for different applications. Since corrugated coupling is wavelength insensitive, it is capable of broadband and multi-color detection. We will present a GaAs/AlGaAs broadband detector based on a binary superlattice design. Incorporating the broadband characteristic in a high gain InGaAs/InP material, C-QWIPs with large background photocurrent can be obtained for high speed applications. For multi-color detection, we have investigated two different approaches. One is based on a voltage-tunable, two-color QWIP material, which can be switched between two detection wavelengths simply by changing the detector bias. Stacking two of these similar QWIPs together and separating them with a middle contact layer, a voltage tunable, four-color detector array can be fabricated. A second approach is to combine a broadband QWIP material with a wavelength-selective light coupling method. Using a light coupling geometry to control the detection wavelength of individual pixels, a large number of wavelengths can be detected based on a single broadband detector material.

Choi, K. K.; Monroy, C.; Goldberg, A.; Dang, G.; Jhabvala, M.; La, A.; Tamir, T.; Leung, K. M.; Majumdar, A.; Li, Jinjin; Tsui, D. C.

2005-10-01

168

Piping Connector  

NASA Technical Reports Server (NTRS)

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

1993-01-01

169

Pulse propagation and electron acceleration in a corrugated plasma channel.  

PubMed

A preformed plasma channel provides a guiding structure for laser pulses unbound by the intensity thresholds of standard waveguides. The recently realized corrugated plasma channel [Layer, Phys. Rev. Lett. 99, 035001 (2007)] allows for the guiding of laser pulses with subluminal spatial harmonics. These spatial harmonics can be phase matched to high energy electrons, making the corrugated plasma channel ideal for the acceleration of electrons. We present a simple analytic model of pulse propagation in a corrugated plasma channel and examine the laser-electron beam interaction. Simulations show accelerating gradients of several hundred MeV/cm for laser powers much lower than required by standard laser wakefield schemes. PMID:18517531

Palastro, J P; Antonsen, T M; Morshed, S; York, A G; Milchberg, H M

2008-03-01

170

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 Å, 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 moiré 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.; Niño, M. A.; Locatelli, A.; Lizzit, S.; Alfè, D.

2011-05-01

171

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

172

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

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

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

173

A comparative study of corrugated horn design by evolutionary techniques  

NASA Technical Reports Server (NTRS)

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

Hoorfar, A.

2003-01-01

174

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

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

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

175

Contribution to the Modelling of the Corrugated Cardboard Behaviour  

E-print Network

The current paper summarizes studies undertaken on the corrugated cardboard. In these studies, a new approach considering the corrugated cardboard as an orthotropic material is developed. This approach permits after homogenization to simplify the numerical calculations and then use a 2D meshing of the corrugated cardboard, instead of a 3D meshing. This will makes it possible to obtain less heavy and less expensive numerical dimensioning studies. The first stage of the studies was a determination of the behaviours of the sandwich and its constituents, which passes by the definition of experimental protocols. Thereafter, an analytical model was proposed and permits to predict the homogenized behaviour of the corrugated cardboard. Finally a tool of decision-making aid was proposed.

Allaoui, Samir; Benzeggagh, M L

2011-01-01

176

MultiMode Coupling Wave Theory for Helically Corrugated Waveguide  

Microsoft Academic Search

Helically corrugated waveguide has been used in various applications such as gyro-backward wave oscillators, gyro-traveling wave amplifier and microwave pulse compressor. A fast prediction of the dispersion characteristic of the operating eigenwave is very important when designing a helically corrugated waveguide. In this paper, multi-mode coupling wave equations were developed based on the perturbation method. This method was then used

Liang Zhang; Wenlong He; Kevin Ronald; Alan D. R. Phelps; Colin G. Whyte; Craig W. Robertson; Alan R. Young; Craig R. Donaldson; Adrian W. Cross

2012-01-01

177

Heat engine with corrugated-shape memory drive belt  

SciTech Connect

An endless drive belt made of shape memory material is entrained about spaced pulleys, one of which projects into a thermal heating region within which the drive belt undergoes contraction to form corrugations therein through which variable spaced contact is established with said one of the pulleys to induce rotation thereof and movement of the belt. The belt expands as it moves out of the thermal heating region causing the corrugations to flatten out as the belt approaches the outer pulley.

Goldstein, D.

1990-07-19

178

Theoretical study of corrugated plates: Shearing of a trapezoidally corrugated plate with trough lines permitted to curve  

NASA Technical Reports Server (NTRS)

A theoretical analysis is presented of the elastic shearing of a trapezoidally corrugated plate with discrete attachments at the ends of the corrugations. Numerical results on effective shear stiffness, stresses, and displacements are presented for selected geometries and end-attachment conditions. It is shown that the frame-like deformation of the cross-sections, which results from the absence of continuous end attachments, can lead to large transverse bending stresses and large reductions in shearing stiffness.

Lin, C.; Libove, C.

1971-01-01

179

Corrugated QWIP developments for tactical infrared imaging  

NASA Astrophysics Data System (ADS)

The corrugated quantum well infrared detector (C-QWIP) offers improvements to quantum efficiency and spectral bandwidth compared to current commercial QWIPs. In addition to improved performance, the C-QWIP also uses manufacturing processes that are mature and low cost. Thus, very large format focal plane arrays (FPAs) can be fabricated with high yield. There are two applications where the C-QWIP can provide cost effective solutions. The first is very large format long-wave infrared (LWIR) sensors. Most very large format FPAs operate in the mid-wave infrared (MWIR). The MWIR band has significantly lower flux than LWIR, therefore in situations where the backgrounds are cold or there is potential motion blur, the LWIR C-QWIP offers better performance. The second application is two-color registered high-resolution wide area imagery. ARL and CE have been developing both C-QWIP detectors and read-out integrated circuits to support these needs. This paper describes the progress we've made in developing high conversion efficiency LWIR C-QWIP FPAs and MWIR/LWIR two-color FPAs and our path forward to multimegapixel C-QWIP FPAs and sensors.

Forrai, David P.; Choi, Kwong-Kit; Devitt, John W.

2007-09-01

180

Surveying drainage culvert use by carnivores: sampling design and cost–benefit analyzes of track-pads vs. video-surveillance methods  

Microsoft Academic Search

Environmental assessment studies often evaluate the effectiveness of drainage culverts as habitat linkages for species, however,\\u000a the efficiency of the sampling designs and the survey methods are not known. Our main goal was to estimate the most cost-effective\\u000a monitoring method for sampling carnivore culvert using track-pads and video-surveillance. We estimated the most efficient\\u000a (lower costs and high detection success) interval

Ana Rita A. Mateus; Clara Grilo; Margarida Santos-Reis

181

Laboratory and Field Performance of Buried Steel-Reinforced High Density Polyethylene (SRHDPE) Pipes in a Ditch Condition under a Shallow Cover  

E-print Network

.16 Placing a pipe in the trench 129 Figure 5.17 Fully instrumented pipes in the trench 130 Figure 5.18 Backfilling and compacting with vibratory plate compactors and tamping hammer 131 Figure 5.19 Backfilling up to springline 132 Figure 5.20 A bobcat... the culvert 135 Figure 5.24 Axle load configuration of the test truck 136 Figure 5.25 The test truck applying static loads 136 Figure 5.26 A truck dumping HMA for the HMA surface 137 Figure 5.27 HMA dumped and leveled using the bobcat 138 Figure 5...

Khatri, Deep Kumar

2014-05-31

182

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

183

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

184

Aerothermodynamic Assessment of Corrugated Panel Thermal Protection Systems  

NASA Technical Reports Server (NTRS)

The feasibility of using corrugated panels as a thermal protection system for an advanced space transportation vehicle was investigated. The study consisted of two major tasks: development of improved correlations for wind tunnel heat transfer and pressure data to yield design techniques, and application of the design techniques to determine if corrugated panels have application future aerospace vehicles. A single-stage-to-orbit vehicle was used to assess advantages and aerothermodynamic penalties associated with use of such panels. In the correlation task, experimental turbulent heat transfer and pressure data obtained on corrugation roughened surfaces during wind tunnel testing were analyzed and compared with flat plate data. The correlations and data comparisons included the effects of a large range of geometric, inviscid flow, internal boundary layer, and bulk boundary layer parameters in supersonic and hypersonic flow.

Brandon, H. J.; Britt, A. H.; Kipp, H. W.; Masek, R. V.

1978-01-01

185

Mode switching in a gyrotron with azimuthally corrugated resonator.  

PubMed

The operation of a gyrotron having a cylindrical resonator with an azimuthally corrugated wall is analyzed. In such a device, wall corrugation cancels the degeneracy of the modes with azimuthally standing patterns. The coupling between these modes depends on the radius of electron beam. It is shown that such a gyrotron can be easily switched from one mode to another. When the switching is done with the repetition frequency equal to the rotational frequency of magnetic islands, this sort of operation can be used for suppression of neoclassical tearing modes in large-scale tokamaks and stellarators. PMID:17677705

Nusinovich, G S; Sinitsyn, O V; Antonsen, T M

2007-05-18

186

Mode Switching in a Gyrotron with Azimuthally Corrugated Resonator  

SciTech Connect

The operation of a gyrotron having a cylindrical resonator with an azimuthally corrugated wall is analyzed. In such a device, wall corrugation cancels the degeneracy of the modes with azimuthally standing patterns. The coupling between these modes depends on the radius of electron beam. It is shown that such a gyrotron can be easily switched from one mode to another. When the switching is done with the repetition frequency equal to the rotational frequency of magnetic islands, this sort of operation can be used for suppression of neoclassical tearing modes in large-scale tokamaks and stellarators.

Nusinovich, G. S.; Sinitsyn, O. V.; Antonsen, T. M. Jr. [IREAP, University of Maryland, College Park, Maryland 20742-3511 (United States)

2007-05-18

187

Hybrid mode transmission in 62-M corrugated waveguide  

NASA Astrophysics Data System (ADS)

Experimental measurements by wavepacket reflectometry are carried out to verify the low transmission loss of hybrid mode on HE(sub 11) in the corrugated waveguide with 88.9 mm in diameter. The HE(sub 11) mode is injected into the 62-m straight circular corrugated waveguide and the beat between the HE(sub 11) and HE(sub 21) (including degenerated TE(sub 01) and TM(sub 02)) modes is observed. The loss is too small to measure and inferred to be less than 2 db/km. The result shows that the use of HE(sub 11) mode for electron cyclotron heating system is suitable.

Ohkubo, K.; Kubo, S.; Iwase, M.; Idei, H.; Sato, M.; Shimozuma, T.; Takita, Y.; Kuroda, T.

1994-09-01

188

The dynamic response of clamped rectangular Y-frame and corrugated core sandwich plates  

E-print Network

the response of sandwich beams with a corrugated core . These studies reveal that geometrical imperfections and1 The dynamic response of clamped rectangular Y-frame and corrugated core sandwich plates V. Rubino identical face-sheets and either Y-frame or corrugated cores. The resistance to shock loading is quantified

Fleck, Norman A.

189

Eikonal approximation in atom-surface scattering: Effects of a corrugated attractive well J. R. Manson  

E-print Network

for the scattering of atomic beams from surfaces, is extended to include a periodic corrugation of the leading edgeEikonal approximation in atom-surface scattering: Effects of a corrugated attractive well J. R for estimating small effects of corrugation of the attractive physisorption potential on the diffraction spectra

Manson, Joseph R.

190

Performance of advanced corrugated-duct solar air collector compared with five conventional designs  

Microsoft Academic Search

This paper presents the results of the experimental investigation and performance analysis of an advanced corrugated duct solar collector. The collector (air heater) is constructed of corrugated surfaces similar to those used for compact heat exchangers, with the air flowing normal to the corrugations. The collector is compared with five other conventional designs constructed and tested during the course of

M. N. Metwally; H. Z. Abou-Ziyan; A. M. El-Leathy

1997-01-01

191

Design of corrugated horn antennas by evolutionary optimization techniques  

Microsoft Academic Search

Corrugated horn antennas are frequently used as the feed elements in reflector antennas for satellite and deep space communications. A particular application is the multifrequency feed horns for the reflector antennas of the JPL\\/NASA Deep Space Network (DSN). In this application, it is desirable to design a horn that has a nearly perfect circularly symmetric pattern (i.e., identical E- and

Vahraz Jamnejad; Ahmad Hoorfar

2004-01-01

192

CLOSED PROCESS WATER LOOP IN NSSC CORRUGATING MEDIUM MANUFACTURE  

EPA Science Inventory

Over the last 5 years, the Green Bay Packaging corrugating medium mill has converted to an essentially closed process water system. The mill is a net consumer of water. This is due to the greater amount of water carried out of the system with the sheet compared to the lower water...

193

The Impulse Response of Extruded Corrugated Core Aluminum Sandwich Structures  

E-print Network

The Impulse Response of Extruded Corrugated Core Aluminum Sandwich Structures A Thesis Presented of distributed impulse loads. However, under the highest intensity loading conditions, nodal failure bonded to the facesheet. The ability of this structure to mitigate distributed and localized impulsive

Wadley, Haydn

194

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

195

Test of superplastically formed corrugated aluminum compression specimens with beaded webs  

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

196

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

PubMed

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

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

2013-01-01

197

DPSM modeling for studying interaction between bounded ultrasonic beams and corrugated plates with experimental verification.  

PubMed

Periodically corrugated structures play an important role in the field of vibration control and for designing structures with desired acoustic band gaps. Analytical solutions for corrugated plates are available for well-defined, smooth corrugations, such as sinusoidal corrugations that are not very common in the real world. Often corrugated plates are fabricated by cutting grooves at regular intervals in a flat plate. No analytical solution is available to predict the wave propagation behavior in such a periodically corrugated plate in which the equation of the plate surface changes periodically between a planar fiat surface and a nonplanar parabolic groove. This problem is solved here for steady-state case by a newly developed semianalytical technique called distributed point source method (DPSM), and the theoretical predictions are compared with the experimental results generated by reflecting a bounded 2.25 MHz ultrasonic beam by a fabricated corrugated plate. The main difference that is observed in the reflected beam profile from a flat plate and a corrugated plate is that the back-scattering effect is much stronger for the corrugated plate, and the forward reflection is stronger for the flat plate. The energy distribution inside the corrugated plate also shows backward propagation of the ultrasonic energy. PMID:17941392

Das, Samik; Dao, Cac Minh; Banerjee, Sourav; Kundu, Tribikram

2007-09-01

198

Direct Acceleration of Electrons in a Corrugated Plasma Channel  

SciTech Connect

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

Palastro, J. P. [Institute for Research in Electrical and Applied Physics, University of Maryland, College Park, MD 20740 (United States); Lawrence Livermore National Laboratory Livermore, CA 94550 (United States); Antonsen, T. M.; Morshed, S.; York, A. G.; Layer, B.; Aubuchon, M.; Milchberg, H. M. [Institute for Research in Electrical and Applied Physics, University of Maryland, College Park, MD 20740 (United States); Froula, D. H. [Lawrence Livermore National Laboratory Livermore, CA 94550 (United States)

2009-01-22

199

Terahertz surface plasmon polaritons on periodically corrugated metal surfaces.  

PubMed

Based on a modal expansion of electromagnetic fields, a rigorous method for analyzing surface plasmon polaritons (SPPs) on a periodically corrugated metal surface has been formulated in this paper. This method takes into account the finite conductivity of the metal as well as higher-order modes within the grooves of the surface structure, thus is able to accurately calculate the loss of these spoof SPPs propagating along the structured surface. In the terahertz (THz) frequency range, the properties of the dispersion and loss of spoof SPPs on corrugated Al surfaces are analyzed. For spoof SPPs at THz frequencies, the strong confinement of the fields is often accompanied with considerable absorption loss, but the performance of both low-loss propagation and subwavelength field confinement for spoof SPPs can be achieved by the optimum design of surface structure. PMID:18542422

Shen, Linfang; Chen, Xudong; Yang, Tzong-Jer

2008-03-01

200

Experimental results on microwave pulse compression using helically corrugated waveguide  

NASA Astrophysics Data System (ADS)

The paper presents new results on the development of a method to generate ultrahigh-power short-microwave pulses by using a known principle of compression (reduction in pulse duration accompanying with increase in pulse amplitude) of a frequency-swept wave packet propagating through a dispersive medium. An oversized circular waveguide with helical-corrugations of its inner surface ensures an eigenwave with strongly frequency dependent group velocity far from cutoff. These dispersive properties in conjunction with high rf breakdown strength and low Ohmic losses make a helically corrugated waveguide attractive for increasing microwave peak power. The experiments performed at kilowatt power levels, demonstrate that an X-band microwave pulse of 80 ns duration with a 5% frequency sweep can be compressed into a 1.5 ns pulse having 25 times higher peak power by optimizing the frequency modulation of the input wave packet.

McStravick, M.; Samsonov, S. V.; Ronald, K.; Mishakin, S. V.; He, W.; Denisov, G. G.; Whyte, C. G.; Bratman, V. L.; Cross, A. W.; Young, A. R.; MacInnes, P.; Robertson, C. W.; Phelps, A. D. R.

2010-09-01

201

Optimization of a corrugated stiffened composite panel under uniaxial compression  

NASA Technical Reports Server (NTRS)

An approach of structural optimization has been used to optimize the weight of a simply supported, corrugated hat stiffened composite panel under uniaxial compression. The approach consists of the employment of nonlinear mathematical programming techniques to reach an optimum solution. Some simplifying assumptions are made in the stress analysis to obtain faster convergence to an optimum solution. With these simplifying assumptions the number of unknown design parameters is reduced to twelve.

Agarwal, B. L.; Sobel, L. H.

1973-01-01

202

Impedance of a Beam Tube with Small Corrugations  

E-print Network

In accelerator projects involving the use of very short bunches, such as the Linac Coherent Light Source (LCLS)-where the rms bunch length in the undulator section is 30 micron-, it appears that even submicron imperfections in the beam tube surface can generate an impedance that is unacceptably large. We consider two periodic models of an imperfect, rough surface, one with small rectangular corrugations, the other with smooth sinusoidal oscillations. We compare the impedance of these two models.

Bane, Karl Leopold Freitag

2000-01-01

203

Corrugation and energetics of graphene on SiO2  

Microsoft Academic Search

Measurements of the topographic structure of graphene on SiO2 are seen to vary considerably between different published reports, particularly with respect to the amplitude of corrugation observed at the few-nm length scale. Intrinsic rippling of the graphene has been reported, in addition to evidence of tip interaction effects. In spite of recent high-resolution STM measurements of exfoliated graphene by several

William Cullen; Mahito Yamamoto; Kristen Burson; Jianhao Chen; Ellen Williams; Michael Fuhrer

2010-01-01

204

Complete light absorption in graphene-metamaterial corrugated structures  

E-print Network

We show that surface-plasmon polaritons excited in negative permittivity metamaterials having shallow periodic surface corrugation profiles can be explored to push the absorption of single and continuous sheets of graphene up to 100%. In the relaxation regime, the position of the plasmonic resonances of the hybrid system is determined by the plasma frequency of the metamaterial, allowing the frequency range for enhanced absorption to be set without the need of engineering graphene.

Ferreira, A; 10.1103/PhysRevB.86.205401

2012-01-01

205

Disappointment and regret enhance corrugator reactivity in a gambling task  

E-print Network

, sounds and words (Bradley & Lang, 2000; Larsen, Norris, & Cacioppo, 2003). In a combined fEMG and functional magnetic resonance imaging study, corrugator responses to negative images were associated with greater activity in the amygdala and a concurrent... ; Larsen et al., 2003), one study reported that monetary wins heightened zygomaticus response relative to losses, in the context of a competition task involving third-party arbitration decisions (Bediou, Mohri, Lack, & Sander, 2011). The purpose...

Wu, Yin; Clark, Luke

2014-01-01

206

Production of hemicellulosic sugars and glucose from residual corrugated cardboard  

Microsoft Academic Search

Corrugated cardboard samples were subjected to two-step saccharification. A first prehydrolysis stage was carried out to solubilise the hemicellulosic fraction as hemicellulosic sugars, and the solid phase from prehydrolysis was used as a substrate for the enzymic hydrolysis of cellulose. The prehydrolysis step was carried out for 0–180min in media containing 1–3wt.% of H2SO4 and the fraction of solid recovered

R Yáñez; J. L Alonso; J. C Parajó

2004-01-01

207

Plasma Heating by an Electron Beam in Corrugated Magnetic Field  

E-print Network

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 heating by the electron beam results in peak electron temperature ~2 keV. To this time the ions are also collectively heated by gradients of electron pressure in the cells of the trap. Ion temperature increases above 1 keV and confines at the high level for ~1 ms. Dense hot plasma in GOL-3 trap emits D-D neutrons for ~1 ms. Details of collective plasma heating by the beam in the corrugated magnetic field will be presented in the paper. New physical mechanism of effective heating of plasma ions, substantially dependent on the corrugation of the magnetic field, is discussed. Experiments with complete multimirror...

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

2004-01-01

208

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

209

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

210

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

211

Interaction of streamers and stationary corrugated ionization waves in semiconductors.  

PubMed

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. PMID:24827322

Kyuregyan, A S

2014-04-01

212

Heat pipe system  

Microsoft Academic Search

A heat pipe diode device for transferring heat from a heat source component to a heat sink wall is described. It contains a heat pipe body member attached to the best source; the heat source having a wall forming at least a portion of the normal evaporator section of the heat pipe diode; a working fluid within the body member;

H. L. Kroebig; F. J. Riha

1974-01-01

213

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

214

Experimental Investigation of the Strength of Multiweb Beams with Corrugated Webs  

NASA Technical Reports Server (NTRS)

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

Fraser, Allister F

1956-01-01

215

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

216

Antenna Performance of a Directly Dug Corrugated Feedhorn for the 150-GHz Band  

NASA Astrophysics Data System (ADS)

We have developed a 150 GHz band corrugated feed horn. These corrugated feed horns have been established by a new machining method, which involves digging corrugations through a metal material. We were able to realize E plane and H plane symmetry, low side lobe level, and low cross-polarization level. Measured co-polarization beam patterns above - 35 dB were consistent with the simulated patterns within a designed frequency range. The peak levels of cross-polarization beam patterns were less than - 30 dB. And, the performances were uniform in several horns. In the present paper, we describe the corrugated horn produced by this methods.

Kimura, Kimihiro; Iwashita, Hiroyuki; Asayama, Shin'ichiro; Sugimoto, Masahiro; Kikuchi, Gumpei; Ogawa, Hideo

2008-08-01

217

Remotely operated pipe connector  

SciTech Connect

An apparatus for remotely assembling and disassembling a connector between a pipe and a closure for the pipe is described, wherein the connector includes an angled flange defining an annular camming surface on the end of the pipe, an angled flange defining an annular camming surface on the closure, two semicircular collars which surround the flanges on the pipe and the closure, each of the collars having annular camming surfaces thereon adapted to contact the annular camming surfaces on the pipe and closure, a nut and bolt means extending through the two collars at each side for drawing the collars together, and an annular sealing ring located between the pipe and closure. The sealing ring is compressed between the pipe and the closure as the camming action of the camming surfaces on the collars against the camming surfaces on the pipe and closure draws the pipe and closure toward one another. The apparatus comprises: a base, a receptacle on the base, the closure being positioned on the receptacle with the flange of the closure upwardmost and horizontally disposed, and the sealing ring resting on the flange; a positioning means for moving the pipe into position vertically above the closure with the flange on the end of the pipe immediately adjacent to and the sealing ring resting on the flange of the closure; a moving means for each collar for reciprocally moving each collar horizontally from a position free of the closure to a position such that the annular camming surfaces on each collar are in contact with the annular camming surfaces on the pipe and closure; and a tensioning means for automatically tightening the nut and bolt means in each side of the collars to draw the collars together and thereby draw the pipe and closure toward one another to cause the seal ring to be compressed between the pipe and closure.

Josefiak, L.J.; Cramer, C.E.

1988-02-16

218

Surveying drainage culvert use by carnivores: sampling design and cost-benefit analyzes of track-pads vs. video-surveillance methods.  

PubMed

Environmental assessment studies often evaluate the effectiveness of drainage culverts as habitat linkages for species, however, the efficiency of the sampling designs and the survey methods are not known. Our main goal was to estimate the most cost-effective monitoring method for sampling carnivore culvert using track-pads and video-surveillance. We estimated the most efficient (lower costs and high detection success) interval between visits (days) when using track-pads and also determined the advantages of using each method. In 2006, we selected two highways in southern Portugal and sampled 15 culverts over two 10-day sampling periods (spring and summer). Using the track-pad method, 90% of the animal tracks were detected using a 2-day interval between visits. We recorded a higher number of crossings for most species using video-surveillance (n = 129) when compared with the track-pad technique (n = 102); however, the detection ability using the video-surveillance method varied with type of structure and species. More crossings were detected in circular culverts (1 m and 1.5 m diameter) than in box culverts (2 m to 4 m width), likely because video cameras had a reduced vision coverage area. On the other hand, carnivore species with small feet such as the common genet Genetta genetta were detected less often using the track-pad surveying method. The cost-benefit analyzes shows that the track-pad technique is the most appropriate technique, but video-surveillance allows year-round surveys as well as the behavior response analyzes of species using crossing structures. PMID:21181260

Mateus, Ana Rita A; Grilo, Clara; Santos-Reis, Margarida

2011-10-01

219

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

220

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

221

Corrugated waveguides as resonance optical filters--advantages and limitations.  

PubMed

The role of the excitation of guided waves propagating in a corrugated dielectric waveguide is discussed in view of the resonance anomalies in reflectivity. Narrow-wavelength filtering properties that are due to these sharp anomalies have been a topic of interest for some time, but a proper understanding of device performances requires an analysis of tolerances with respect to the incident-beam collimation and to waveguide losses. Such an analysis is proposed in this paper, and the conclusion is that the incident-beam divergence plays a critical role in reducing the maximum reflectivity for narrow-band filters. PMID:11444572

Popov, E; Bozhkov, B

2001-07-01

222

Helium-adsorbate cross section on highly corrugated substrates  

SciTech Connect

The interaction of He atoms with adsorbates placed on strongly corrugated substrates is investigated both theoretically and experimentally. An analysis of the scattering process within the transition matrix approach suggests that the normalized differential cross section, associated with the attenuation of coherent diffraction due to incoherent scattering in the presence of adsorbates, is expected to be largest for the most intense coherent diffraction peaks. For the adsorption of K on Cu(115), this trend is experimentally observed. {copyright} {ital 1996 The American Physical Society.}

Armand, G.; Schwenger, L.; Ernst, H. [Commisariat a lEnergie Atomique Saclay, Departement de Recherche sur lEtat Condense, les Atomes et les Molecules/Service de Recherche sur les Surfaces et lIrradiation de la Matiere, 91191 Gif Sur Yvette (France)] [Commisariat a lEnergie Atomique Saclay, Departement de Recherche sur lEtat Condense, les Atomes et les Molecules/Service de Recherche sur les Surfaces et lIrradiation de la Matiere, 91191 Gif Sur Yvette (France)

1996-02-01

223

Trivelpiece-Gould modes in a corrugated plasma slab  

SciTech Connect

It is shown that the spectrum of electrostatic oscillations in a periodically corrugated plasma slab exhibits spatial mode locking, i.e., for each spectral branch there is an infinity of subbands with constant wave numbers. The widths of the largest subbands are evaluated. We also show that the eigenmodes are represented by a set of double layers. Under certain conditions, the initial problem for wave propagation is solved. The interaction of an electron beam with a plasma is studied and the corresponding instability growth rate is obtained.

Ignatov, A.M. (General Physics Institute, 38 Vavilova St., Moscow (Russian Federation))

1995-02-01

224

Radiation generated by bunched electron beams in corrugated plasma channels  

SciTech Connect

The excitation of radiation by bunched electron beams propagating in miniature corrugated plasma channels is considered. It is shown that the rate at which power is radiated by a beam is characterized by impedance that depends on the properties of the channel. For experimentally obtainable parameters radiation bursts of multiple millijoules can be achieved. The spectrum of the radiation can be made narrow and controlled through the properties of the channel. The effects of spatial variations in the channel parameters on the spectrum are also described.

Antonsen, Thomas M. Jr. [Centre de Physique Theorique, Ecole Polytechnique, CNRS, Palaiseau 91128 (France) and Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742 (United States)

2010-07-15

225

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

2014-12-22

226

Abrasion resistant heat pipe  

DOEpatents

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

Ernst, D.M.

1984-10-23

227

Heat pipe investigations  

NASA Technical Reports Server (NTRS)

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

Marshburn, J. P.

1972-01-01

228

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

229

External artery heat pipe  

NASA Technical Reports Server (NTRS)

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

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

1989-01-01

230

Internal pipe attachment mechanism  

DOEpatents

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

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

1994-12-13

231

Steerable Free Space Optical Interconnect with Corrugated Waveguide Gratings Optically Isolated by  

E-print Network

Steerable Free Space Optical Interconnect with Corrugated Waveguide Gratings Optically Isolated.kwong@utexas.edu, raychen@uts.cc.utexas.edu Abstract-An optical phased array of corrugated waveguide gratings is fabricated for applications in which beam steering elements are used to route optical signals between two ends of a link

Chen, Ray

232

Quasi-phase-matched acceleration of electrons in a corrugated plasma channel S. J. Yoon,1  

E-print Network

Quasi-phase-matched acceleration of electrons in a corrugated plasma channel S. J. Yoon,1 J. P in a corrugated plasma channel is composed of spatial harmonics whose phase velocities can be subluminal the interaction length. Here we examine the fully self-consistent interaction of the laser pulse and electron beam

Milchberg, Howard

233

Low voltage and high transmittance blue-phase liquid crystal displays with corrugated electrodes  

E-print Network

Low voltage and high transmittance blue-phase liquid crystal displays with corrugated electrodes BPLC display is proposed. The periodic corrugated electrodes generate a strong horizontal field along the beam path is large, resulting in low voltage and high transmittance. This approach enables

Wu, Shin-Tson

234

Probing the mechanical properties of graphene using a corrugated elastic substrate  

E-print Network

microscale-corrugated elastic substrates and few layer graphene FLG . By using an atomic force microscope AFM FLG-FLG step height. An example of AFM-folded FLG is shown in Fig. 2 a . The areas of the grapheneProbing the mechanical properties of graphene using a corrugated elastic substrate Scott

Goldbart, Paul M.

235

Manipulation of Thought Content as a Determinant of Mood and Corrugator Electromyographic Activity in Depressed Patients  

ERIC Educational Resources Information Center

Examines the effects of unhappy thoughts on mood and corrugator EMG (electromyographic activity) in depressed patients. Its purpose was to obtain evidence relevant to cognitive models of depression and to examine the usefulness of corrugator EMG as an indicator of depressed mood. (Author/RK)

Teasdale, John D.; Bancroft, Judy

1977-01-01

236

An analytical homogenization model for finite element modelling of corrugated cardboard  

Microsoft Academic Search

In this paper, an analytical homogenization model for corrugated cardboard and its numerical implementation in a shell element are presented. Taking into account the geometric and mechanical properties of the corrugated board components, this homogenization model leads to an elastic stiffness matrix relative to the generalized strains and internal efforts for an equivalent orthotropic plate. Special attentions are paid to

N. Talbi; A. Batti; R. Ayad; Y. Q. Guo

2009-01-01

237

Effects of the environmental conditions on the mechanical behaviour of the corrugated cardboard  

Microsoft Academic Search

Corrugated cardboard is very sensitive to atmospheric conditions. The aim of this work is to study the effects of these parameters, in fact the relative humidity (RH), on the mechanical behaviour of a sandwich structure of the corrugated cardboard type. For that, tensile tests were used under various rates of relative humidity. In high rates of moisture, the instrumentation must

S. Allaoui; Z. Aboura; M. L. Benzeggagh

2009-01-01

238

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

E-print Network

vi Table of Contents 1. Introduction 1 2. Background 4 2.1. Corrugated Fiber Board 4 2.2. Tag Performance Reduction in Proximity to Water 4 2.3. Moisture in Corrugated Fiberboard 5 2.4. Dielectric Properties of Corrugated Fiberboard 7... of Fiberboard 6 2. Measured Dielectric Properties of Corrugated Paperboard 8 3. Phase of the Input Impedance at Different Frequency Regions 16 1 1. Introduction According to a report released by the U.S. Government Accountability Office...

Sivakumar, Mutharasu

2008-02-01

239

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

240

Embedded corrugated long-period fiber gratings for sensing applications.  

PubMed

We demonstrate a method to make possible the mass production of corrugated long-period fiber gratings (C-LPFGs) by utilizing imprint lithography on polycarbonate (PC) substrates. For such C-LPFGs whose working principle is based on photoelastic effect, pretensile tension is required to be applied to inducing periodical refractive index variation. We then present an attempt to use PC as embedding material for providing internal compressive stress for C-LPFGs to have a photoelastic effect. This type of LPFG, termed embedded corrugated long-period fiber gratings (EC-LPFGs), is obtained after reimprinting the C-LPFGs into other PC substrates. Since compressive stress is retained due to the materials of different coefficients of thermal expansion (CTE), unlike C-LPFGs, EC-LPFGs can serve as strain, bending, and temperature sensors without the need of pretensile strain. The two most troublesome problems, the fragility of an etched fiber grating and the requirement of pretensile strain, can be simultaneously alleviated or solved by EC-LPFGs. PMID:22505062

Wang, Hsiao-Yuh; Chuo, Shih-Min; Huang, Chih-Yu; Wang, Lon A

2012-04-01

241

Theory of a ubitron in a corrugated waveguide  

SciTech Connect

A K{sub a} band ubitron amplifier is currently under development at NRL utilizing grazing intersection for wide instantaneous bandwidth, circularly polarized wiggler and microwave fields for high gain and power, and a high quality Pierce gun generating a cylindrical, uniform density electron beam for high efficiency. The dispersion characteristics of a periodic waveguide can be exploited for low voltage ubitron operation. Operation in the HE{sub 11} mode of a corrugated cylindrical waveguide permits broader bandwidth amplification at lower voltages than is possible with a smooth waveguide. While the wave is slower than the smooth waveguide dispersion characteristic, the amplifier still operates on the fundamental space harmonic as a fast-wave device. An extensive investigation of several waveguide/wiggler geometries has been completed. Preliminary calculations using a dielectrically loaded corrugated waveguide indicate that 20% bandwidth operation in K{sub a} band is possible at voltages {approximately} 150 kV with a 8--9 mm period wiggler generating a 930 G transverse magnetic field. Design details and performance calculations using the 3-D nonlinear code TARANTULA will be presented.

Freund, H.P.; Nguyen, K.; Pershing, D.E. [Naval Research Lab., Washington, DC (United States)

1996-12-31

242

The low velocity impact response of sandwich beams with a corrugated core or a Y-frame core  

E-print Network

1 The low velocity impact response of sandwich beams with a corrugated core or a Y-frame core L. St sandwich beams with corrugated and Y-frame cores have been measured in a drop-weight apparatus at 5 ms-1-statically. Moreover, the corrugated and Y-frame core beams had similar performances. Three-dimensional finite element

Fleck, Norman A.

243

Suppression of Corrugated Boundaries in Multilayer Fresnel Zone Plate for Hard X-Ray Synchrotron Radiation Using Cylindrical Slit  

Microsoft Academic Search

Corrugated zone roughness of a circular Cu\\/Al multilayer Fresnel zone plate (FZP) was successfully suppressed. Such a zone corrugation was often observed in the concentric multilayers prepared using a conventional sputtering apparatus. The zone corrugation is a consequence of the oblique component of the deposition flux (i.e. shadowing effect). We therefore set a cylindrical slit (a linear slit on the

Masato Yasumoto; Shigeharu Tamura; Nagao Kamijo; Yoshio Suzuki; Mitsuhiro Awaji; Akihisa Takeuchi; Hidekazu Takano; Yoshiki Kohmura; Katsumi Handa

2001-01-01

244

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

245

Non-Classical Smoothening of Nano-Scale Surface Corrugations  

SciTech Connect

We report the first experimental observation of non-classical morphological equilibration of a corrugated crystalline surface. Periodic rippled structures with wavelengths of 290-550 nm were made on Si(OO1) by sputter rippling and then annealed at 650 - 750 °C. In contrast to the classical exponential decay with time, the ripple amplitude, A{lambda}(t), followed an inverse linear decay, A{lambda}(t)= A{lambda}(0)/(1 +k{lambda}t), agreeing with a prediction of Ozdemir and Zangwill. We measure the activation energy for surface relaxation to be 1.6±0.2 eV, consistent with an interpretation that dimers mediate transport.

Aziz, Michael J.; Chason, Eric; Erlebacher, Jonah; Floro, Jerrold A.; Sinclair, Michael B.

1999-05-20

246

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

247

Modeling noncontact atomic force microscopy resolution on corrugated surfaces  

PubMed Central

Summary Key developments in NC-AFM have generally involved atomically flat crystalline surfaces. However, many surfaces of technological interest are not atomically flat. We discuss the experimental difficulties in obtaining high-resolution images of rough surfaces, with amorphous SiO2 as a specific case. We develop a quasi-1-D minimal model for noncontact atomic force microscopy, based on van der Waals interactions between a spherical tip and the surface, explicitly accounting for the corrugated substrate (modeled as a sinusoid). The model results show an attenuation of the topographic contours by ~30% for tip distances within 5 Å of the surface. Results also indicate a deviation from the Hamaker force law for a sphere interacting with a flat surface. PMID:22496996

Burson, Kristen M; Yamamoto, Mahito

2012-01-01

248

A nonlinear investigation of corrugation instabilities in magnetic accretion shocks  

NASA Astrophysics Data System (ADS)

Accretion shock waves are present in many important astrophysical systems and have been a focus of research for decades. These investigations provide a large body of understanding as to the nature, characteristics, and evolutionary behaviors of accretion shock waves over a wide range of conditions. However, largely absent are investigations into the properties of accretion shock waves in the presence of strong magnetic fields. In such cases these strong magnetic fields can significantly alter the stability behaviors and evolution of the accretion shock wave through the production and propagation of magnetic waves as well as magnetically constrained advection. With strong magnetic fields likely found in a number of accretion shock systems, such as compact binary and protostellar systems, a better understanding of the behaviors of magnetic accretion shock waves is needed. A new magnetohydrodynamics simulation tool, IMOGEN, was developed to carry out an investigation of instabilities in strong, slow magnetic accretion shocks by modelling their long-term, nonlinear evolution. IMOGEN implements a relaxed, second-order, total variation diminishing, monotonic upwind scheme for conservation laws and incorporates a staggered-grid constrained transport scheme for magnetic advection. Through the simulated evolution of magnetic accretion shocks over a wide range of initial conditions, it has been shown, for sufficiently high magnetic field strengths, that magnetic accretion shocks are generally susceptible to corrugation instabilities, which arise in the presence of perturbations of the initial shock front. As these corrugation instabilities grow, they manifestas magnetic wave propagation in the upstream region of the accretion column, which propagate away from the accretion shock front, and as density columns, or fingers, that grow into the higher density downstream flow, defined and constrained by current loops created during the early evolution of the instability.

Ernst, Scott

2011-05-01

249

Plasmon resonance absorption in layered structures of silver with periodic corrugation  

SciTech Connect

Plasmon resonance absorption in periodically corrugated layered structures of silver was studied by the photoacoustic method. The layered structures were self-supporting and corrugated with a period of 1888 nm and amplitude varying from 6 to 12 nm, depending on the thickness. Experimental results of resonance absorption of 633-nm photons were analyzed in terms of the propagation and damping constants of coupled modes of surface plasmons. The coupling efficiency of incident photons to these modes was found to be strongly dependent on corrugation amplitude and layer thickness.

Arakawa, E.T.; Inagaki, T.; Goudonnet, J.P.

1987-01-01

250

Automated Ultrasonic Pipe Weld Inspection  

Microsoft Academic Search

Summary This article contains an overview on automated ultrasonic w eld inspection for various pipe types. Some inspection steps might by carried out with portable t est equipment (e.g. pipe end test), but the weld inspection in all internationally relevant specif ications must be automated. The pipe geometry, the production process, and the further pipe usage determine if ND T

Wolfram A. Karl; Peter SCHULTE; Michael JOSWIG; Rainer KATTWINKEL

251

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

252

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

253

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

254

Heat Pipe Systems  

NASA Technical Reports Server (NTRS)

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

1993-01-01

255

DRAINAGE PIPE DETECTOR  

Technology Transfer Automated Retrieval System (TEKTRAN)

One of the more frustrating problems confronting farmers and land improvement contractors in the Midwestern United States involves locating buried agricultural drainage pipes. Conventional geophysical methods, particularly ground penetrating radar (GPR), presently being used for environmental and co...

256

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

257

Characterization of multiple reflections and phase space properties for a periodically corrugated waveguide  

NASA Astrophysics Data System (ADS)

Dynamical properties for a beam light inside a sinusoidally corrugated waveguide are discussed in this paper. The beam is confined inside two mirrors: one is flat and the other one is sinusoidally corrugated. The evolution of the system is described by the use of a two-dimensional and nonlinear mapping. The phase space of the system is of mixed type therefore exhibiting a large chaotic sea, periodic islands and invariant KAM curves. A careful discussion of the numerical method to solve the transcendental equations of the mapping is given. We characterize the probability of observing successive reflections of the light by the corrugated mirror and show that it is scaling invariant with respect to the amplitude of the corrugation. Average properties of the chaotic sea are also described by the use of scaling arguments.

Silva, Mário R.; da Costa, Diogo Ricardo; Leonel, Edson D.

2012-07-01

258

Bending Tests of Circular Cylinders of Corrugated Aluminum-alloy Sheet  

NASA Technical Reports Server (NTRS)

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

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

1937-01-01

259

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

E-print Network

will be discussed, current prevalent practices in the industry will be elaborated and potential measures for energy use and cost savings will be outlined. The results from detailed energy audits of 12 large corrugated cardboard production plants in California...

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

2005-01-01

260

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

261

Atomistic origin of radial corrugation in a few-walled carbon nanotubes: A molecular dynamics study  

NASA Astrophysics Data System (ADS)

We perform molecular dynamics simulations of a few-walled (with 3-4 walls) carbon nanotubes using empirical interatomic potential. We demonstrate that the radial corrugation occurs in such thin nanotubes under hydrostatic pressure, which is apparently similar to the corrugation in thicker (e.g., several tens-walled) nanotubes that had been predicted using continuum mechanics approximation. The mechanism underlying the corrugation of a few-walled nanotubes, however, is found to be much distinct from thick nanotubes; i.e., the sp3 bonds between adjacent concentric walls and registry of atom arrangement take important roles in the formation and stabilization of corrugation modes in a few-walled nanotubes.

Umeno, Yoshitaka; Koike, Ikuyo; Kusano, Ayako; Shima, Hiroyuki; Sato, Motohiro

2015-01-01

262

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

NASA Astrophysics Data System (ADS)

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

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

263

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

NASA Astrophysics Data System (ADS)

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

McKinnon, Mark B.

264

Singular and Hypersingular Integral Equations Techniques for Gyrotron Coaxial Resonators with a Corrugated Insert  

Microsoft Academic Search

For the first time rigorous theory is developed for eigen traveling TM modes in the resonator of the coaxial cavity gyrotron\\u000a with a corrugated insert. This mathematical model can be applied for any corrugation parameters and wavelengths. Gyrotron\\u000a simulation software is developed and allows to calculate mode eigenvalues, electromagnetic field components and Ohmic losses\\u000a for eigen TE and TM modes.

Oleksiy S. Kononenko; Yuriy V. Gandel

2007-01-01

265

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

266

PIPES: A Portable Integrated Piping Engineering Interface System  

SciTech Connect

This paper describes software developed by the authors to integrate and automate several piping engineering applications for high-volume production use in the power and petrochemical industries. The system utilizes piping component geometry from a CAD model together with associated engineering and material data. It produces input for an industry-standard piping isometric drawing program, Electronic Data Interchange information for pipe spool fabrication, and input for several,common pipe stress analysis codes. The piping isometric drawings feature stress analysis data points and material tabulations. The software is based on an open architecture and incorporates rule-driven Expert System technology to provide flexibility and ease of customization.

Lee, N.L.; Kanga, D. [Bechtel Corp., Gaithersburg, MD (United States)

1995-12-01

267

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

268

Superradiance of short electron pulses in regular and corrugated waveguides  

SciTech Connect

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

Ginzburg, N.S.; Konoplev, I.V.; Sergeev, A.S. [Institute of Applied Physics, Nizhny Novgorod (Russian Federation)] [and others

1995-12-31

269

Driving corrugated donut rotors with Laguerre-Gauss beams.  

PubMed

Tightly-focused laser beams that carry angular momentum have been used to trap and rotate microrotors. In particular, a Laguerre-Gauss mode laser beam can be used to transfer its orbital angular momentum to drive microrotors. We increase the torque efficiency by a factor of about 2 by designing the rotor such that its geometry is compatible with the driving beam, when driving the rotation with the optimum beam, rather than beams of higher or lower orbital angular momentum. Based on Floquet's theorem, the order of discrete rotational symmetry of the rotor can be made to couple with the azimuthal mode of the Laguerre-Gauss beam. We design corrugated donut rotors, that have a flat disc-like profile, with the help of the discrete dipole approximation and the T-matrix methods in parallel with experimental demonstrations of stable trapping and torque measurement. We produce and test such a rotor using two-photon photopolymerization. With a rotor that has 8-fold discrete rotational symmetry, an outer radius of 1.85 ?m and a hollow core radius of 0.5 ?m, we were able to transfer approximately 0.3 h? per photon of the orbital angular momentum from an LG04 beam. PMID:25321053

Loke, Vincent L Y; Asavei, Theodor; Stilgoe, Alexander B; Nieminen, Timo A; Rubinsztein-Dunlop, Halina

2014-08-11

270

Order–disorder transition for corrugated Au layers  

SciTech Connect

Atomic-scale structure of the growth of a gold film on (1 1 2) plane of Mo single crystal was investigated by means of low energy electron diffraction (LEED) and scanning tunneling microscopy (STM) up to two monolayers (ML) of gold coverage. Both LEED and STM results establish that Au grows on Mo(1 1 2) in a layer-by-layer mode, for at least the first two monolayers. A number of ordered structures are formed and both the first and second layers adopt the Mo(1 1 2) 1 × 1 surface structure upon completion. For some gold layers on Mo(1 1 2), notably the 1.66 monolayer 3 × 1 and 1.75 monolayer 4 × 1 gold overlayers, we find evidence of a phase transition associated with increasing disorder in gold layers with structural corrugation and anisotropic band structure. The signature of this phase transition, at temperatures in the range of 400–500 K, is a sharp decrease in the overlayer effective Debye temperature.

Fukutani, Keisuke; Lozova, N.; Zuber, S. M.; Dowben, P. A.; Galiy, P.; Losovyl, Yaroslav B.

2010-01-01

271

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

272

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

273

46 CFR 119.455 - Fuel piping.  

Code of Federal Regulations, 2013 CFR

...construction of fuel lines, including pipe, tube, and hose, must comply...piping of other materials, such as seamless steel pipe or tubing, which provide equivalent...installation of fuel lines, including pipe, tube, and hose, must...

2013-10-01

274

46 CFR 182.455 - Fuel piping.  

Code of Federal Regulations, 2014 CFR

...construction of fuel lines, including pipe, tube, and hose, must comply...piping of other materials, such as seamless steel pipe or tubing, which provide equivalent...installation of fuel lines, including pipe, tube, and hose, must...

2014-10-01

275

46 CFR 182.455 - Fuel piping.  

Code of Federal Regulations, 2013 CFR

...construction of fuel lines, including pipe, tube, and hose, must comply...piping of other materials, such as seamless steel pipe or tubing, which provide equivalent...installation of fuel lines, including pipe, tube, and hose, must...

2013-10-01

276

46 CFR 119.455 - Fuel piping.  

Code of Federal Regulations, 2011 CFR

...construction of fuel lines, including pipe, tube, and hose, must comply...piping of other materials, such as seamless steel pipe or tubing, which provide equivalent...installation of fuel lines, including pipe, tube, and hose, must...

2011-10-01

277

46 CFR 119.455 - Fuel piping.  

Code of Federal Regulations, 2010 CFR

...construction of fuel lines, including pipe, tube, and hose, must comply...piping of other materials, such as seamless steel pipe or tubing, which provide equivalent...installation of fuel lines, including pipe, tube, and hose, must...

2010-10-01

278

46 CFR 119.455 - Fuel piping.  

Code of Federal Regulations, 2012 CFR

...construction of fuel lines, including pipe, tube, and hose, must comply...piping of other materials, such as seamless steel pipe or tubing, which provide equivalent...installation of fuel lines, including pipe, tube, and hose, must...

2012-10-01

279

46 CFR 119.455 - Fuel piping.  

Code of Federal Regulations, 2014 CFR

...construction of fuel lines, including pipe, tube, and hose, must comply...piping of other materials, such as seamless steel pipe or tubing, which provide equivalent...installation of fuel lines, including pipe, tube, and hose, must...

2014-10-01

280

Apparatus for moving a pipe inspection probe through piping  

DOEpatents

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

Zollinger, W. Thor (Martinez, GA); Appel, D. Keith (Aiken, SC); Lewis, Gregory W. (North Augusta, SC)

1995-01-01

281

Apparatus for moving a pipe inspection probe through piping  

DOEpatents

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

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

1995-07-18

282

Heat pipe cooled probe  

NASA Technical Reports Server (NTRS)

The basic heat pipe principle is employed to provide a self-contained passively cooled probe that may be placed into a high temperature environment. The probe consists of an evaporator region of a heat pipe and a sensing instrument. Heat is absorbed as the working fluid evaporates in the probe. The vapor is transported to the vapor space of the condenser region. Heat is dissipated from the condenser region and fins causing condensation of the working fluid, which returns to the probe by gravity and the capillary action of the wick. Working fluid, wick and condenser configurations and structure materials can be selected to maintain the probe within an acceptable temperature range.

Camarda, C. J. (inventor); Couch, L. M.

1984-01-01

283

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,

284

Heat transfer in pipes  

NASA Technical Reports Server (NTRS)

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

Burbach, T.

1985-01-01

285

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

286

Suppression of Corrugated Boundaries in Multilayer Fresnel Zone Plate for Hard X-Ray Synchrotron Radiation Using Cylindrical Slit  

NASA Astrophysics Data System (ADS)

Corrugated zone roughness of a circular Cu/Al multilayer Fresnel zone plate (FZP) was successfully suppressed. Such a zone corrugation was often observed in the concentric multilayers prepared using a conventional sputtering apparatus. The zone corrugation is a consequence of the oblique component of the deposition flux (i.e. shadowing effect). We therefore set a cylindrical slit (a linear slit on the surface of a stainless steel cylindrical shield) between the target and the substrate in order to eliminate the oblique flux. As a result, the zone corrugation was not observed using a scanning ion microscope (SIM).

Yasumoto, Masato; Tamura, Shigeharu; Kamijo, Nagao; Suzuki, Yoshio; Awaji, Mitsuhiro; Takeuchi, Akihisa; Takano, Hidekazu; Kohmura, Yoshiki; Handa, Katsumi

2001-07-01

287

Heat Pipe With Interrupted Slot  

NASA Technical Reports Server (NTRS)

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

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

1994-01-01

288

Preventing and Thawing Frozen Pipes  

MedlinePLUS

... do freeze. Why Pipe Freezing is a Problem Water has a unique property in that it expands as it freezes. This expansion puts tremendous pressure on whatever is containing it, including ... a container, expanding water can cause pipes to break. Pipes that freeze ...

289

Reusable high-temperature heat pipes and heat pipe panels  

NASA Technical Reports Server (NTRS)

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

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

1989-01-01

290

Heat pipe investigations  

NASA Technical Reports Server (NTRS)

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

Marshburn, J. P.

1973-01-01

291

Aeronautical tubes and pipes  

NASA Astrophysics Data System (ADS)

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

Beauclair, N.

1984-12-01

292

Heat pipe dynamic behavior  

Microsoft Academic Search

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

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

1988-01-01

293

Phase-matched air ultrasonic transducers using corrugated PVDF film with half wavelength depth.  

PubMed

A new type of large area PVDF film air transducer is proposed. The transducer features a high power output and a sharp beam angle. Conventionally known curved length mode resonators with two clamps at both ends have a resonance frequency determined by the curvature. In the present work, PVDF was formed into alternating concave and convex multiple curved sections, eliminating clamps, i.e., a periodic corrugation structure using a single PVDF film. Each convex and concave section has a common resonance frequency. A common excitation voltage induces vibration for each section, and the vibration direction is normal to the film surface. The vibration phase of convex section is shifted 180 degrees from the concave section. These waves add constructively to form a strong acoustic beam when corrugation height is approximately one-half of the wavelength. The corrugation height controls propagation path difference, canceling excitation phase difference. The design principle based on a uniform vibration mode is presented. Experimental investigations using 8.8 x 2.5-, 10 x 5-, and 20 x 20-cm2 transducers are presented. Side lobes unique to this corrugation structure have been observed. A theoretical analysis of the side lobes is also presented. According to the theory, choosing the corrugation height appropriately will reduce side lobes to -15 dB with regard to the main lobe, and the observed side lobe height agreed with the theoretical result. PMID:11800119

Toda, M

2001-11-01

294

Coherent mode coupling in highly efficient top-emitting OLEDs on periodically corrugated substrates.  

PubMed

Bragg scattering at one-dimensional corrugated substrates allows to improve the light outcoupling from top-emitting organic light-emitting diodes (OLEDs). The OLEDs rely on a highly efficient phosphorescent pin stack and contain metal electrodes that introduce pronounced microcavity effects. A corrugated photoresist layer underneath the bottom electrode introduces light scattering. Compared to optically optimized reference OLEDs without the corrugated substrate, the corrugation increases light outcoupling efficiency but does not adversely affect the electrical properties of the devices. The external quantum efficiency (EQE) is increased from 15 % for an optimized planar layer structure to 17.5 % for a corrugated OLED with a grating period of 1.0 ?m and a modulation depth of about 70 nm. Detailed analysis and optical modeling of the angular resolved emission spectra of the OLEDs provide evidence for Bragg scattering of waveguided and surface plasmon modes that are normally confined within the OLED stack into the air-cone. We observe constructive and destructive interference between these scattered modes and the radiative cavity mode. This interference is quantitatively described by a complex summation of Lorentz-like resonances. PMID:24718126

Schwab, Tobias; Fuchs, Cornelius; Scholz, Reinhard; Zakhidov, Alexander; Leo, Karl; Gather, Malte C

2014-04-01

295

Polarized Raman spectroscopy of corrugated MBE grown GaAs (6¯3¯1¯) homoepitaxial films  

NASA Astrophysics Data System (ADS)

In this work, we present a Raman scattering study of GaAs layers grown on (6¯3¯1¯)-oriented substrates by molecular beam epitaxy. A set of samples whose morphology sustained different corrugation order were grown by MBE by varying the growth parameters such as temperature and As/Ga flux ratio. We employed polarized Raman spectroscopy using the backscattering configurations Z(XX) Z¯, Z(XY) Z¯ and Z(YY)Z¯. According to the calculated dipole selection rules both TO and LO phonons are allowed for backscattering from a perfect GaAs (6¯3¯1¯) crystal, but with the intensity of the TO phonon much larger than that of the LO phonon. However, it is found that the selection rules differ for corrugated samples. Besides, the TO/LO phonon resonances intensity ratio and the LO peak asymmetry depend on the corrugation order of the samples.

Espinosa-Vega, L. I.; Rodriguez, A. G.; Cruz-Hernandez, E.; Martinez-Veliz, I.; Rojas-Ramirez, J.; Ramirez-Lopez, M.; Nieto-Navarro, J.; Lopez-Lopez, M.; Mendez-Garcia, V. H.

2013-09-01

296

Reduction of out-of-plane warpage in surface micromachined beams using corrugation  

NASA Astrophysics Data System (ADS)

Corrugation is proposed as a means of reducing the out-of-plane warpage in surface micromachined beams that result from an asymmetric vertical stress profile. Corrugation increases beam bending stiffness without increasing film thickness, making the beam more immune to intrinsic vertical stress gradients without requiring longer film deposition times, increased beam mass, or careful stress optimization. The technique was tested using a dual-thickness metal surface micromachining process with a photoresist sacrificial layer. Several corrugation patterns and geometries were tested, and the best performing pattern was implemented on a MEMS actuator array. The off-state to on-state capacitance delta of the array improved from 0.24 to 0.7pF and the beam curvature decreased from 180 to 50 nm compared with an uncorrugated array. Other device performance parameters, such as 30 V pull-in voltage and 5 billion cycle switching lifetime, were unaffected.

Gupta, Arun; Barron, Lance; Brainin, Michael; Lee, Jeong-Bong

2014-06-01

297

Effect of inertia on film flow over oblique and three-dimensional corrugations  

NASA Astrophysics Data System (ADS)

The gravity-driven flow of a liquid film down an inclined plane wall with small-amplitude two-dimensional oblique or three-dimensional doubly periodic corrugations is investigated for finite Reynolds numbers. The film surface may exhibit constant or variable surface tension due to an insoluble surfactant. The key idea is to express the wall geometry as a Fourier series, and then reconstruct the three-dimensional flow in terms of the individual two-dimensional transverse and unidirectional flows over the constituent oblique two-dimensional corrugations. Three-dimensional corrugations may either reduce or amplify the surface deformation with respect to their two-dimensional counterparts due to the simultaneous effect of the constituent oblique components on the effective wave number, capillary number, and Reynolds number.

Luo, Haoxiang; Pozrikidis, C.

2006-07-01

298

Measurement and correlation of aerodynamic heating to surface corrugation stiffened structures in thick turbulent boundary layers  

NASA Technical Reports Server (NTRS)

The flow conditions for which heating distributions were measured on corrugated surfaces and wavy walls in turbulent boundary layers are shown, along with the ratio of the displacement thickness to the roughness height versus the local edge Mach number for an equivalent smooth surface. The present data are seen to greatly extend the range of data available on corrugated surfaces in turbulent boundary layers. These data were obtained by testing fullscale corrugation roughened panels in the wall boundary layer of a supersonic and hypersonic wind tunnel. The experimental program used to obtain the data is described. The data are analyzed and correlated in terms of the pertinent flow and geometric parameters. The developed correlations are compared with the available thin boundary layer data, as well as with previously published correlation techniques.

Brandon, H. J.; Masek, R. V.

1974-01-01

299

Two-color corrugated quantum-well infrared photodetector for remote temperature sensing  

NASA Astrophysics Data System (ADS)

A quantum-well infrared photodetector (QWIP) based on the corrugated light-coupling scheme has been fabricated and tested for remote temperature sensing. The QWIP consists of two stacks of multiple quantum wells (MQWs), each sensitive in one of the atmospheric infrared transmission windows and each with a separate readout circuit. High optical coupling efficiency is obtained in both wavelength ranges, demonstrating the use of the corrugated structure for two-color detection. By monitoring the ratio of the photocurrent generated simultaneously in each MQW stack, the temperature of the object emitting the radiation can be determined, regardless of its emissivity and the geometrical factors. This temperature sensing ability is tested by using a blackbody radiator with precision temperature control as the target. The agreement between the measured and the preset temperatures indicates that the corrugated QWIP is capable of precision thermometric measurements.

Chen, C. J.; Choi, K. K.; Chang, W. H.; Tsui, D. C.

1998-01-01

300

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

NASA Astrophysics Data System (ADS)

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

Jegley, D.

1993-01-01

301

Theoretical investigation on guiding IR light in hollow-core metallic fiber with corrugated inner surface.  

PubMed

Hollow metallic fibers (HMFs) are in general lossy primarily owing to the fact that the guided transverse-magnetic (TM) light sustains a relatively high propagation loss. In this paper, we propose a type of practical hollow-core metallic fiber (HMF) with longitudinally corrugated inner surface for transmitting infrared (IR) light. Simulation results show that the loss of the fundamental TM mode can be easily reduced by 50~100 times compared to a HMF without surface corrugation. In contrast to the traditional HMF with a dielectric coating, it is shown that the loss of the fundamental TM mode in the proposed HMF is relatively insensitive to the corrugation layer thickness or equivalently the operating frequency. PMID:20941096

Liu, Hairong; Yan, Min; Qiu, Min; Liu, Deming; Yu, Xia; Zhang, Ying

2010-10-11

302

June 15, 1999 / Vol. 24, No. 12 / OPTICS LETTERS 817 Two-dimensional colloidal crystal corrugated waveguides  

E-print Network

June 15, 1999 / Vol. 24, No. 12 / OPTICS LETTERS 817 Two-dimensional colloidal crystal corrugated the first time, two-dimensional (2D) corrugated waveguides at optical wavelengths obtained by use of 2D that have been designed are one dimensional (1D) coupling beams propagating in opposite directions. Two

Avrutsky, Ivan

303

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

304

Nonlinear finite-difference time-domain modeling of linear and nonlinear corrugated waveguides  

SciTech Connect

A multidimensional, nonlinear finite-difference time-domain (NL-FDTD) simulator, which is constructed from a self-consistent solution of the full-wave vector Maxwell equations and dispersive (Lorentz), nonlinear (finite-time-response Raman and instantaneous Kerr) materials models, is used to study finite-length, corrugated, optical waveguide output couplers and beam steerers. Multiple-cycle, ultrashort-optical-pulse interactions with these corrugated, nonlinear, dispersive waveguides are characterized. An all-optical nonlinear beam-steering device is designed, and its output-coupling performance is characterized with this NL-FDTD simulator.

Ziolkowski, R.W.; Judkins, J.B. (Electromagnetics Laboratory, Department of Electrical and Computer Engineering, The University of Arizona, Tucson, Arizona 85721 (United States))

1994-09-01

305

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

NASA Technical Reports Server (NTRS)

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

Wood, Donald H

1930-01-01

306

Linear theory of electromagnetic wave generation in a plasma-loaded corrugated-wall resonator  

SciTech Connect

A linear theory of the excitation of electromagnetic waves in a plasma-filled corrugated-wall waveguide with an arbitrarily large sinusoidal corrugation has been derived and analyzed numerically. The theory predicts that, when driven by an electron beam, the presence of a plasma in the slow wave structure will cause an increase in the oscillation frequency, and that the temporal growth rates of a high-frequency mode approach those of fundamental mode for high plasma densities. The latter result may account for the high-frequency modes observed in the authors' plasma-filled backward-wave oscillator.

Minami, K.; Carmel, Y.; Granatstein, V.L.; Destler, W.W.; Kens, R.A.; Lou, W.R.; Abe, D.K. (Maryland Univ., College Park, MD (USA). Lab. for Plasma Research); Ali, M.M.; Hosokawa, T.; Ogura, K. (Dept. of Electrical Engineering, Niigata Univ., Niigata 950-21 (JP)); Watanabe, T. (National Institute for Fusion Science, Nagoya (JP))

1990-06-01

307

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

308

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

SciTech Connect

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

Liu, X. L.; Zhang, Z. M., E-mail: zhuomin.zhang@me.gatech.edu [G. W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)

2014-06-23

309

Analysis on field lines and Poynting vectors in corrugated wall waveguides  

NASA Astrophysics Data System (ADS)

Field patterns and Poynting vectors of TM(01) mode in sinusoidally corrugated waveguides are analyzed numerically. It is shown that a plasma column near the axis excludes the RF electric field lines toward the peripheral region, resulting in increased Poynting vectors in the axial direction there. The excitation of TM(01) mode in corrugated waveguides is shown to be classified into two cases: surface and the volume waves. A possible physical explanation for the enhanced radiation observed previously from plasma filled backward wave oscillators is tried from the present results.

Ogura, Kazuo; Minami, Kazuo; Ali, M. M.; Kan, Yoshinori; Nomura, Takahiro; Aiba, Yasushi; Sugawara, Akira; Watanabe, Tsuguhiro

1992-11-01

310

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

311

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

312

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

313

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

314

The three-point bending of Y-frame and corrugated core sandwich beams V. Rubino, V.S. Deshpande n  

E-print Network

The three-point bending of Y-frame and corrugated core sandwich beams V. Rubino, V.S. Deshpande n Three-point bending a b s t r a c t Sandwich beams comprising Y-frame and corrugated cores have been of the beams is governed by the indentation of the Y-frame or corrugated core for all beam geometries

Fleck, Norman A.

315

48th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, April 2326, Waikiki, Hawaii Novel Multistable Corrugated Structures  

E-print Network

(m-1 ) Corrugation wavelength (m) Poisson's ratio a Corrugation amplitude at a point, measured from the two states; at no point is the deformation plastic. PhD candidate, Structures Group, University-linear geometrical changes during deformation. Two modes of bistability are described here: prestressed corrugated

Guest, Simon

316

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

317

Heat pipe technology: A bibliography with abstracts  

NASA Technical Reports Server (NTRS)

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

1971-01-01

318

Insulating Cryogenic Pipes With Frost  

NASA Technical Reports Server (NTRS)

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

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

1985-01-01

319

Radiation crosslinked plasticized PVC - pipes  

NASA Astrophysics Data System (ADS)

The efficiency of polyfunctional monomers triallyl cyanurate, allyl methacrylate, diallyl phtalate, 2-ethyl-2(hydroxy-methyl)-propanediol-(1,3) trimethacrylate, divinyl benzene and ethylene glycol dimethacrylate in radiation crosslinking of PVC was investigated. Patterns of pipes were produced and irradiated with gamma rays. The resistance to internal pressure of crosslinked PVC pipes was measured at 80°C and compared with resistance of unirradiated PVC pipes.

Hell, Z.; Ravli?, M.; Bogdanovi?, Lj.; Maleš, J.; Dvornik, I.; Ranogajec, F.; Ranogajec, M.; Tudori?-Ghemo, J.

320

Numerical heat-pipe modeling  

Microsoft Academic Search

The research described in this paper was conducted to better understand numerical modeling of heat-pipe transients. In the numerical model, the vapor flow was assumed to be unsteady, compressible and one-dimensional, while the one-dimensional, unsteady, heat diffusion equation was used to model energy conduction through the heat-pipe wall. The liquid return process in the heat-pipe wick was not modeled. Finite

Jerry Bowman; Richard W. Sweeten

1989-01-01

321

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

322

Bragg spectroscopy for measuring Casimir-Polder interactions with Bose-Einstein condensates above corrugated surfaces  

E-print Network

We propose a method to probe dispersive atom-surface interactions by measuring via two-photon Bragg spectroscopy the dynamic structure factor of a Bose-Einstein condensate above corrugated surfaces. This method takes advantage of the condensate coherence to reveal the spatial Fourier components of the lateral Casimir-Polder interaction energy.

Gustavo A. Moreno; Diego A. R. Dalvit; Esteban Calzetta

2009-04-01

323

Relativistic electron beam induced amplification of surface wave propagating over a corrugated metal surface  

NASA Astrophysics Data System (ADS)

An impedance model is constructed in the framework of a quasi-optical approach, which describes the propagation of radiation over a corrugated metal surface and its amplification by a rectilinear relativistic electron beam. It is shown that this scheme can provide effective amplification of radiation in a submillimeter wavelength range.

Ginzburg, N. S.; Malkin, A. M.; Zheleznov, I. V.; Sergeev, A. S.; Kocharovskaya, E. R.

2013-03-01

324

Dynamic Stability of Crack Fronts: Out-Of-Plane Corrugations Mokhtar Adda-Bedia,1  

E-print Network

Dynamic Stability of Crack Fronts: Out-Of-Plane Corrugations Mokhtar Adda-Bedia,1 Rodrigo E. Arias) The dynamics and stability of brittle cracks are not yet fully understood. Here we use the Willis- Movchan 3D of planar crack fronts in the framework of linear elastic fracture mechanics. We discuss a minimal scenario

Adda-Bedia, Mokhtar

325

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

326

Scattering of xenon from Ni,,111...: Collision-induced corrugation and energy transfer dynamics  

E-print Network

Scattering of xenon from Ni,,111...: Collision-induced corrugation and energy transfer dynamics in which a beam of xenon atoms collides with a clean Ni 111 surface, and the speed and angular is independent of initial and final scattering angles. This result is attributed to multiple xenon

Zare, Richard N.

327

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

DOEpatents

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

Zhu, Yuntian T. (Los Alamos, NM); Lowe, Terry C. (Santa Fe, NM); Jiang, Honggang (Los Alamos, NM); Huang, Jianyu (Los Alamos, NM)

2001-01-01

328

Direct Acceleration of Electrons in a Corrugated Plasma Waveguide A. G. York* and H. M. Milchberg  

E-print Network

Direct Acceleration of Electrons in a Corrugated Plasma Waveguide A. G. York* and H. M. Milchberg) Historically, direct acceleration of charged particles by electromagnetic fields has been limited- field acceleration of electrons over many centimeters using relatively small femtosecond lasers. We

Milchberg, Howard

329

PHYSICAL REVIEW B 84, 115401 (2011) Making angle-resolved photoemission measurements on corrugated monolayer crystals  

E-print Network

monolayer crystals: Suspended exfoliated single-crystal graphene Kevin R. Knox,1,2 Andrea Locatelli,3 Mehmet conducted on epitaxial graphene, which has been grown on a variety of substrates such as SiC, Ru, Ni, and Ir by the crystal corrugation. However, by combining surface morphology measurements of the graphene roughness

Kim, Philip

330

CFD CODE APPLICATION TO FLOW THROUGH NARROW CHANNELS WITH CORRUGATED WALLS  

Microsoft Academic Search

Novel compact condensers and in general two-phase heat exchangers made of corrugated plates hold significant advantages over conventional equipment. In an effort to optimise design and operation of this type of equipment, a commercial CFD code (CFX?) is employed to simu- late the flow through an element of a model compact heat exchanger and to provide informa- tion on the

S. V. Paras; A. G. Kanaris; A. A. Mouza; A. J. Karabelas

331

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

332

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° < Ø < 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, Ø = 180° and channel height, S = 12.5 mm.

Sakr, Mohamed

2015-01-01

333

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

E-print Network

Negative linear classical magnetoresistance in a corrugated two-dimensional electron gas N. M (Received 18 August 2004; published 20 December 2004) Large linear negative magnetoresistance (LNMR.50.Bk I. INTRODUCTION Recently the classical low-field magnetoresistance (MR) in metals

Gusev, Guennady

334

Automatic system for corrugated and cardboard boxes rotary cutting die rule preparation  

Microsoft Academic Search

This document describes design and implementation of an automated environment for a rule cutting machine in the fabrication of rotary cutting dies for corrugated and cardboard boxes. The steps involved begin with the processing of the data obtained from the CAD program of die design. There is a brief mechanical report of the machine. The hardware, and software tools associated

H. J. Rana; Enrique Soto; J. Farina

1995-01-01

335

Preserving the strength of corrugated cardboard under high humidity condition using nano-sized mists  

Microsoft Academic Search

The paper evaluates the adsorption of water vapor and compression strength of three types of commercially made corrugated cardboard boxes for packing strawberry, mizuna and broccoli. The experiments were conducted on the specimens and empty cardboard boxes at constant temperature and 95% relative humidity (RH). The samples were stored under the environments of two types of mists, namely nanomist and

Duong Van Hung; Yusuke Nakano; Fumihiko Tanaka; Daisuke Hamanaka; Toshitaka Uchino

2010-01-01

336

Automatic Segmentation of Rotary Dies for the Production of Corrugated Cardboard Boxes  

Microsoft Academic Search

Corrugated cardboard boxes are widely used for packaging of merchandise to be transported worldwide. These boxes are produced by means of flat or rotary machines that perform cutting, creasing or perforating operations on the cardboard. The main element of both flat and rotary machines is the die that implements the layout of the box to be fabricated. During the last

José Fariña; J. Luis Mato; Juan J. Rodríguez-Andina; Marian Adamski; José M. Villacieros

2005-01-01

337

Phenomena governing uni-axial tensile behaviour of paperboard and corrugated cardboard  

Microsoft Academic Search

Paperboard exhibits a complex mechanical behaviour, which is governed by several phenomena. This work proposes a contribution to the identification of these phenomena. Uni-axial tensile tests under various configurations were carried out on the paperboard and corrugated cardboard. Observations under scanning electron microscopy were thereafter done in order to identify the microscopic phenomena produced in the structure. These observations made

S. Allaoui; Z. Aboura; M. L. Benzeggagh

2009-01-01

338

Polymeric heat pipe wick  

NASA Technical Reports Server (NTRS)

A wick for use in a capillary loop pump heat pipe is described. The wick material is an essentially uniformly porous, permeable, open-cell, polyethylene thermoplastic foam having an ultrahigh average molecular weight of from approximately 1 to 5 million, and an average pore size of about 10 to 12 microns. A representative material having these characteristics is POREX UF, which has an average molecular weight of about 3 million. This material is fully compatible with the FREONs and anhydrous ammonia and allows for the use of these very efficient working fluids in capillary loops.

Seidenberg, Benjamin

1988-01-01

339

Intermediate Temperature Fluids for Heat Pipes and Loop Heat Pipes  

Microsoft Academic Search

Potential working fluids for heat pipes and loop heat pipes include water, organic fluids, elements, and halides. The paper surveys life tests conducted with 30 different intermediate temperature working fluids, and over 60 different working fluid\\/envelope combinations. Life tests have been run with three elemental working fluids: sulfur, sulfur-iodine mixtures, and mercury. Other fluids offer benefits over these three liquids

William G. Anderson; John R. Hartenstine; David B. Sarraf; Calin Tarau

340

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

341

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

342

Building a Copper Pipe "Xylophone."  

ERIC Educational Resources Information Center

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

Lapp, David R.

2003-01-01

343

Heat pipe transient response approximation  

Microsoft Academic Search

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

2001-01-01

344

Heat pipe transient response approximation  

Microsoft Academic Search

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

Robert S. Reid

2002-01-01

345

Heat Pipe Blocks Return Flow  

NASA Technical Reports Server (NTRS)

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

Eninger, J. E.

1982-01-01

346

Turbulence Transition in Pipe Flow  

Microsoft Academic Search

Pipe flow is a prominent example among the shear flows that undergo transition to turbulence without mediation by a linear instability of the laminar profile. Experiments on pipe flow, as well as plane Couette and plane Poiseuille flow, show that triggering turbulence depends sensitively on initial conditions, that between the laminar and the turbulent states there exists no intermediate state

Bruno Eckhardt; Tobias M. Schneider; Bjorn Hof; Jerry Westerweel

2007-01-01

347

Vibration analysis methods for piping  

Microsoft Academic Search

Attention is given to flow vibrations in pipe flow induced by singularity points in the piping system. The types of pressure fluctuations induced by flow singularities are examined, including the intense wideband fluctuations immediately downstream of the singularity and the acoustic fluctuations encountered in the remainder of the circuit, and a theory of noise generation by unsteady flow in internal

R. J. Gibert

1981-01-01

348

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

349

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

350

Prometheus Hot Leg Piping Concept  

SciTech Connect

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. [Bechtel Bettis, Inc., Bettis Atomic Power Laboratory, West Mifflin, PA 15122 (United States); DiLorenzo, Peter A. [KAPL, Inc., Knolls Atomic Power Laboratory, Schenectady, NY 12301 (United States)

2007-01-30

351

Numerical heat-pipe modeling  

NASA Astrophysics Data System (ADS)

The research described in this paper was conducted to better understand numerical modeling of heat-pipe transients. In the numerical model, the vapor flow was assumed to be unsteady, compressible and one-dimensional, while the one-dimensional, unsteady, heat diffusion equation was used to model energy conduction through the heat-pipe wall. The liquid return process in the heat-pipe wick was not modeled. Finite difference techniques were used to solve the governing equations. Damping was needed to stabilize the numerical scheme. To validate the numerical model, experimental data was obtained from a copper-water heat-pipe start-up. The heat-pipe's external evaporator and condenser temperatures were recorded during the experiment. In the paper, the results from the numerical model are compared to the experimental data.

Bowman, Jerry; Sweeten, Richard W.

1989-06-01

352

Vibration analysis methods for piping  

NASA Astrophysics Data System (ADS)

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

Gibert, R. J.

1981-09-01

353

Technology for concrete pipe manipulator  

NASA Astrophysics Data System (ADS)

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

Li, Bin; Wang, Dan; Lin, Renzhi

2010-01-01

354

Technology for concrete pipe manipulator  

NASA Astrophysics Data System (ADS)

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

Li, Bin; Wang, Dan; Lin, Renzhi

2009-12-01

355

The role of surface corrugation in direct translationally activated dissociative adsorption  

NASA Astrophysics Data System (ADS)

Recent experimental results concerning reactive scattering in the hyperthermal kinetic energy regime can be described by energy scaling relationships Ei cosn ?i, where n<2, and Ei and ?i are the incident kinetic energy and incident angle, respectively. Such power law scaling arguments are empirical, the results of which cannot easily be related to the fundamental parameters that describe the gas-surface interaction. We present a detailed and thorough analysis where the role of surface corrugation in determining the coupling between incident kinetic energy and incident angle in these translationally activated systems is considered explicitly. The key features of the analysis involve the assumption that the kinetic energy directed along the local surface normal (E?) controls the reaction probability (SR), and that by averaging this quantity over the unit cell, one obtains the appropriate energy scaling relationship. The major advantage associated with the proposed analysis is that one need not assume a functional form concerning how the reaction probability depends on kinetic energy, i.e., SR(E?). Our analysis demonstrates that in the absence of shadowing, a single ``universal'' scaling function exists Ei?(?i), which is given by the expression ?(?i)=(1-?)cos2 ?i+3? sin2 ?i, where ? is a corrugation parameter (0???1) and only in-plane corrugation has been considered. Shadowing plays an important role at sufficiently large corrugation amplitudes and/or sufficiently large angles of incidence. Specifically, it leads to more complex scaling functions, which depend on the shape of the surface corrugation, for which several examples have been considered. Both local minima and local maxima can be observed for ?(?i) as a function of incident angle. Two factors can introduce errors in the analysis, namely, the presence of nonlinearities, and the effects of nonuniform surface reactivity, and illustrative examples are considered. The model accounts well for recent experimental results concerning the dissociation of silanes on silicon surfaces, and alkanes on a corrugated platinum surface. It is probable that other systems involving reactive scattering in the hyperthermal kinetic energy regime may also be described well employing this analysis.

Xia, Li-Qun; Engstrom, J. R.

1994-09-01

356

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

NASA Technical Reports Server (NTRS)

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

Chen, J. C.

1995-01-01

357

Superconducting pipes and levitating magnets.  

PubMed

Motivated by a beautiful demonstration of the Faraday and the Lenz laws in which a small neodymium magnet falls slowly through a conducting nonferromagnetic tube, we consider the dynamics of a magnet falling coaxially through a superconducting pipe. Unlike the case of normal conducting pipes, in which the magnet quickly reaches the terminal velocity, inside a superconducting tube the magnet falls freely. On the other hand, to enter the pipe the magnet must overcome a large electromagnetic energy barrier. For sufficiently strong magnets, the barrier is so large that the magnet will not be able to penetrate it and will be levitated over the mouth of the pipe. We calculate the work that must done to force the magnet to enter a superconducting tube. The calculations show that superconducting pipes are very efficient at screening magnetic fields. For example, the magnetic field of a dipole at the center of a short pipe of radius a and length L approximately > a decays, in the axial direction, with a characteristic length xi approximately 0.26a. The efficient screening of the magnetic field might be useful for shielding highly sensitive superconducting quantum interference devices. Finally, the motion of the magnet through a superconducting pipe is compared and contrasted to the flow of ions through a trans-membrane channel. PMID:17280160

Levin, Yan; Rizzato, Felipe B

2006-12-01

358

3D Quasioptical Theory of Terahertz Superradiance of an Extended Electron Bunch Moving Over a Corrugated Surface  

NASA Astrophysics Data System (ADS)

We consider the superradiance of an extended relativistic electron bunch moving over a periodically corrugated surface for the generation of multimegawatt terahertz pulses. To study the above process we have developed a three-dimensional, self-consistent, quasioptical theory of Cherenkov stimulated emission which includes a description of the formation of an evanescent wave over a corrugated surface and its excitation by rf current induced in the electron bunch.

Ginzburg, N. S.; Malkin, A. M.; Sergeev, A. S.; Zotova, I. V.; Zaslavsky, V. Yu.; Zheleznov, I. V.

2013-05-01

359

3D quasioptical theory of terahertz superradiance of an extended electron bunch moving over a corrugated surface.  

PubMed

We consider the superradiance of an extended relativistic electron bunch moving over a periodically corrugated surface for the generation of multimegawatt terahertz pulses. To study the above process we have developed a three-dimensional, self-consistent, quasioptical theory of Cherenkov stimulated emission which includes a description of the formation of an evanescent wave over a corrugated surface and its excitation by rf current induced in the electron bunch. PMID:23683205

Ginzburg, N S; Malkin, A M; Sergeev, A S; Zotova, I V; Zaslavsky, V Yu; Zheleznov, I V

2013-05-01

360

The effects of corrugation and wing planform on the aerodynamic force production of sweeping model insect wings  

Microsoft Academic Search

The effects of corrugation and wing planform (shape and aspect ratio) on the aerodynamic force production of model insect\\u000a wings in sweeping (rotating after an initial start) motion at Reynolds number 200 and 3500 at angle of attack 40 are investigated,\\u000a using the method of computational fluid dynamics. A representative wing corrugation is considered. Wing-shape and aspect ratio\\u000a (AR) of

Guoyu Luo; Mao Sun

2006-01-01

361

Abrasion protection in process piping  

SciTech Connect

Process piping often is subjected to failure from abrasion or a combination of abrasion and corrosion. Abrasion is a complex phenomenon, with many factors involved to varying degrees. Hard, mineral based alumina ceramic and basalt materials are used to provide protection against abrasion in many piping systems. Successful life extension examples are presented from many different industries. Lined piping components require special attention with regard to operating conditions as well as design and engineering considerations. Economic justification involves direct cost comparisons and avoided costs.

Accetta, J. [Abresist Corp., Urbana, IN (United States)

1996-07-01

362

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

363

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

364

D0 Silicon Upgrade: Upgrade Piping Loads on Cleanroom Roof  

SciTech Connect

The proposed piping layout for the DO upgrade will run along the south wall of DAB. The cryogenic service pipe runs above the upper and lower cleanroom roofs and will need to be supported by the roofs beams. Calculations were done to determine the stresses in the I-beams created by the existing and additional loads due to the upgrade. Refer to drawing no. 3823.115-ME-317283 for drawings of the piping layout. Figure 1 shows the 'plan view' portion of this drawing. The weight of the individual lines were calculated in figure 2 assuming a pipe density of O.28 lbm/in{sup 3} for stainless steel (0.12% C) and a fluid density (assuming LN2 at 1 atm) of 0.03 lbm/in{sup 3}. The weights of the corrugated steel flooring, assembly hall feed cans, support beams, and roof hatch were also included in the analysis. These loads are calculated on pgs. 5-6. A floor load of 50 lbf/ft{sup 2} was also added in order to maintain the existing floor load limit in addition to the added piping loads. Measurements of the dimensions of the I-beams determined that the nominal sizes of the beams were W8 x 21 for the lower roof and W14 x 26 for the upper roof. Pipe lengths were determined from the drawing for each of the lines on pgs. 1-2 of the calculations (refer to all piping by line numbers according to figure 2). A total weight was calculated for lines 3-9 along the south wall and lines 1-2 running along the north wall of the lower cleanroom roof. To simplify the calculations these weights were assumed to be evenly distributed on the 5 I-beam supports of the lower cleanroom roof 2.5 feet in from the south wall. The stress analysis was done using FrameMac, a 2-D finite element program for the Macintosh. Beam 3 was not included in the analysis because it is structurally equivalent to beam 1. The program outputted maximum values for shear stress, bending stress, shear force, and moments in each of the beams analyzed. These values were then compared to the allowable stresses as per the specifications and codes stated in the AISC: Manual of Steel Construction. The stresses on the roof beams needed to be determined in a number of different places. The first was in the beam itself which included the flange and web sections. The second place was at the ends of the beams where the flanges were removed to make the perpendicular connections to the other beams on the lower roof. The final point was the framed beam connection which included the bolt analysis. FrameMac calculated stresses only for the beams which included the sections where the flanges were removed to make the end connections. To analyze the connections, the allowable bending and shear stresses were solved for allowable shear and moments. This was done because FrameMac does not have the capability to analyze the dimensions for the bolts and angles used in the connections were known and the program outputted values for reaction forces and moments at the ends of the beams. Multiplying the allowable shear stress for the bolts and angle connections by their respective areas gave the allowable shear force. The allowable moment for the angle connection was calculated by multiplying the section modulus of the angle by the allowable bending stress. These allowable loads are calculated on pgs. 7-8. The allowable and maximum calculated stresses by FrameMac are summarized in a table. In conclusion, the cleanroom roofs will be able to safely support the weight of the upgrade cryogenic piping, feed cans, corrugated flooring and a 50 lbf/ft{sup 2} floor load with the addition of diagonal braces at the ends of beams 1,2,3,4, and 8. The location and size of these diagonal braces are shown in fig. 4. Also, the piping supports and feed cans will all need to be placed directly above the I-beam supports. These supports will consist of unistrut structures that will be detailed and specified separate to this analysis. The output and input data from FrameMac and the drawings used in the analysis follow the calculation pages.

Sakla, Steve; /Fermilab

1995-08-28

365

Longitudinal stability of a coasting beam in a corrugated resistive vacuum chamber  

E-print Network

An analysis is made of the electromagnetic fields excited by longitudinal density fluctuations of an unbunched relativistic particle beam drifting in a corrugated vacuum chamber of circular cross section. From these fields the coupling impedance is calculated, which is a measure of the reaction of an oscillating beam upon itself, and determines its stability. The coupling impedances of bellows and cross-section variations are investigated as functions of various geometric and beam parameters. Corrugations of a vacuum chamber may become resonant cavities at higher frequencies. The coupling impedance (divided by the mode number) may become several orders of magnitude larger than its value at lower frequencies, and severely endanger beam stability. The resonant coupling impedances can be found directly by computer solution of the matrix equations for the field coefficients. (11 refs).

Keil, Eberhard

1972-01-01

366

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

367

Focused ion beam lithography for fabrication of suspended nanostructures on highly corrugated surfaces.  

PubMed

We propose a nanofabrication method that allows for patterning on extremely corrugated surfaces with micrometer-size features. The technique employs focused ion beam nanopatterning of ion-sensitive inorganic resists formed by atomic layer deposition at low temperature. The nanoscale resolution on corrugated surfaces is ensured by inherently large depth of focus of a focused ion beam system and very uniform resist coating. The utilized TiO? and Al?O? resists show high selectivity in deep reactive ion etching and enable the release of suspended nanostructures by dry etching. We demonstrate the great flexibility of the process by fabricating suspended nanostructures on flat surfaces, inclined walls, and on the bottom of deep grooves. PMID:25074238

Erdmanis, M; Sievilä, P; Shah, A; Chekurov, N; Ovchinnikov, V; Tittonen, I

2014-08-22

368

Focused ion beam lithography for fabrication of suspended nanostructures on highly corrugated surfaces  

NASA Astrophysics Data System (ADS)

We propose a nanofabrication method that allows for patterning on extremely corrugated surfaces with micrometer-size features. The technique employs focused ion beam nanopatterning of ion-sensitive inorganic resists formed by atomic layer deposition at low temperature. The nanoscale resolution on corrugated surfaces is ensured by inherently large depth of focus of a focused ion beam system and very uniform resist coating. The utilized TiO2 and Al2O3 resists show high selectivity in deep reactive ion etching and enable the release of suspended nanostructures by dry etching. We demonstrate the great flexibility of the process by fabricating suspended nanostructures on flat surfaces, inclined walls, and on the bottom of deep grooves.

Erdmanis, M.; Sievilä, P.; Shah, A.; Chekurov, N.; Ovchinnikov, V.; Tittonen, I.

2014-08-01

369

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

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

370

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

SciTech Connect

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

Moustafa, S.E.; Rodehaver, S.M. [Wiss, Janney, Elstner Associates, Inc., Seattle, WA (United States); Frier, W.A. [Westinghouse Hanford Co., Richland, WA (United States)

1993-10-01

371

Electrodynamical properties of an experimental corrugated slow-wave structure in its different passbands  

NASA Astrophysics Data System (ADS)

Numerical simulations of the eigenwave properties of the experimental corrugated slow-wave structure in the lowest and two higher its passbands for the TM-type waves have been carried out by means of the electrodynamical methods of linear theory of the Cerenkov type devices. A detailed comparative analysis of the frequency dependencies obtained at these passbands for the transmission coefficients as well as the mode analysis of the passed and reflected power flows have been made. Longitudinal distributions of the electric field axial component at resonance frequencies of the used structure have been considered. The electrodynamical properties of the experimental corrugated slow-wave structure in its two higher passbands are shown to be similar to each other but appreciably differing from the ones in the lowest passband of the E01 mode. This is explained by a hybrid character of the waves in the indicated higher passbands of the used structure.

Chernyavskiy, Igor A.; Pikunov, Viktor M.

2000-07-01

372

Enhanced efficiency of organic light-emitting devices by employing a periodically corrugated conductive photoresist  

NASA Astrophysics Data System (ADS)

Photons trapped in the form of waveguide (WG) modes associated with the organic/organic interface and in the form of surface plasmon polariton (SPP) modes associated with the metallic electrode/organic interface result in a large energy loss in organic light-emitting devices (OLEDs). We demonstrate the efficient outcoupling of WG and SPP modes by integrating a wavelength-scale periodically corrugated conductive photoresist into the device structure. The corrugated OLEDs with appropriate grating periods lead to a 15.9% increase in efficiency compared with the planar OLEDs. The efficient outcoupling of the WG and SPP modes is verified by the numerical simulation of both the emission spectra and the field distribution.

Bai, Yu; Fan, Yi; Lu, Qipeng; Wang, Xiaoyi; Chu, Minghui; Liu, Xingyuan

2015-02-01

373

Corrugation reduction in periodically inverted GaAs by molecular beam epitaxy growth using arsenic dimers  

NASA Astrophysics Data System (ADS)

Molecular beam epitaxy (MBE) regrowth of GaAs on periodically inverted GaAs(100) substrates using arsenic dimers (As2) was studied. We found that we can reduce corrugations on the regrown GaAs by MBE growth using As2 at considerably higher substrate temperatures (?450 °C) than in the case of growth using arsenic tetramers (?300 °C). This result indicates that As2 MBE regrowth can be used to fabricate highly efficient GaAs/AlGaAs wavelength conversion waveguiding devices owing to a reduction in the propagation losses caused by interface corrugations. We also estimated the diffusion lengths of Ga atoms coexisting with As2 on GaAs(100) surfaces from experimental thickness variations on the basis of a diffusion equation analysis.

Narasaki, Ryota; Matsushita, Tomonori; Kondo, Takashi

2015-02-01

374

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

375

Determination of Secondary Encasement Pipe Design Pressure  

SciTech Connect

This document published results of iterative calculations for maximum tank farm transfer secondary pipe (encasement) pressure upon failure of the primary pipe. The maximum pressure was calculated from a primary pipe guillotine break. Results show encasement pipeline design or testing pressures can be significantly lower than primary pipe pressure criteria.

TEDESCHI, A.R.

2000-10-26

376

Grooving mill for pipe-heating department  

Microsoft Academic Search

To meet the rising demands on the strength and quality of seamless pipe, heat-treatment sections must be organized at pipe plants. To obtain the required geometric parameters of the pipe, a grooving mill for heat treatment of external pipe diameter over the whole length is established in the heating department. In accordance with the reequipment program at OAO Sinarskii Trubnyi

N. V. Pasechnik; N. A. Tselikov; A. I. Grinshpun; G. A. Furlender; A. V. Chekulaev

2007-01-01

377

Heat pipe technology: A bibliography with abstracts  

NASA Technical Reports Server (NTRS)

A cumulative bibliography on heat pipe research and development projects is presented. The subjects discussed are: (1) general information, (2) heat pipe applications, (3) heat pipe theory, (4) design and fabrication, (5) testing and operation, (6) subject and author index, and (7) heat pipe related patents.

1971-01-01

378

A homogeneous heat pipe design code  

NASA Technical Reports Server (NTRS)

A computer program was developed to facilitate parametric performance evaluation of heat pipes in lightweight heat rejection systems. A description of the code, user's manual, and sample inputs are provided. The emphasis is placed on the analysis and design of homogeneous wick heat pipes. The analysis of the annular heat pipe is included as part of the heat pipe radiator subroutine.

Nakashima, A. M.; Kikin, G. M.

1974-01-01

379

Acoustic Signal Processing for Pipe Condition Assessment  

EPA Science Inventory

Unique to prestressed concrete cylinder pipe (PCCP), individual wire breaks create an excitation in the pipe wall that may vary in response to the remaining compression of the pipe core. This project was designed to improve acoustic signal processing for pipe condition assessment...

380

Analysis of perforated-pipe watercollector systems  

Microsoft Academic Search

When there is the need for domestic or industrial use of water from a natural stream or lake, a filtering process through layers of soil and a perforated collector-pipe system is customarily used. The water enters the pipe through a series of small opening cut in the pipe wall. Discharge through the pipe increasing as flow proceeds along its length.

Rouhollah Fatahi; Otto Haszpra

2004-01-01

381

Heat pipe experiment on SPAS 01  

NASA Astrophysics Data System (ADS)

The second flight of Challenger carried a heat pipe experiment, designed to measure the performance of constant conductance heat pipe diodes over a period of 16 hr. The experiment platform and the flight results on variable conductance heat pipe housekeeping radiators, including the temperature distribution at these heat pipe versus experiment time are presented. All equipment is shown to be space qualified.

Kock, H.; Kreeb, H.; Savage, C.

1986-08-01

382

Highly efficient antenna system using a corrugated horn and scanning hyperbolic reflector  

NASA Technical Reports Server (NTRS)

In a horn-reflector antenna system for producing a spherical aperture phase front, a corrugated conical horn illuminates a section of a hyperbolic reflector to produce a spherical aperture phase front. This front produces a far field beam with low sidelobes and high beam efficiency. The system is insensitive to frequency and polarization changes, and is also insensitive to orientation about the axis of the conical horn for beam scanning.

Green, K. A. (inventor)

1976-01-01

383

The electrical characteristics of a conical horn-reflector antenna employing a corrugated horn  

Microsoft Academic Search

The electrical properties of a conical horn-reflector antenna of 2-3° beamwidth have been investigated over the frequency range of 12-18 GHz. It is shown that the employment of a corrugated horn reduces the characteristic spillover side lobe of the conical horn-reflector antenna by 15 dB and yields excellent main beam circularity over the full Ku band. This results from the

Ghassan Yassin; Martin Robson; Peter J. Duffett-Smith

1993-01-01

384

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

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

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

385

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; Chabé, Julien; Salem, Ran; David, Tal; Groswasser, David; Keil, Mark; Japha, Yonathan; Folman, Ron

2014-09-01

386

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

387

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

388

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

PubMed

A 250-GHz corrugated transmission line with a directional coupler for forward and backward power monitoring has been constructed and tested for use with a 25-W continuous-wave gyrotron for dynamic nuclear polarization (DNP) experiments. The main corrugated line (22-mm internal diameter, 2.4-m long) connects the gyrotron output to the DNP probe input. The directional coupler, inserted approximately midway, is a four-port crossed waveguide beamsplitter design. Two beamsplitters, a quartz plate and ten-wire array, were tested with output coupling of 2.5% (-16 dB) at 250.6 GHz and 1.6% (-18 dB), respectively. A pair of mirrors in the DNP probe transferred the gyrotron beam from the 22-mm waveguide to an 8-mm helically corrugated waveguide for transmission through the final 0.58-m distance inside the NMR magnet to the sample. The transmission-line components were all cold tested with a 248 ± 4-GHz radiometer. A total insertion loss of 0.8 dB was achieved for HE(11) -mode propagation from the gyrotron to the sample with only 1% insertion loss for the 22-mm-diameter waveguide. A clean Gaussian gyrotron beam at the waveguide output and reliable forward power monitoring were achieved for many hours of continuous operation. PMID:17901907

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

2005-06-01

389

Aerodynamic heating to corrugation stiffened structures in thick turbulent boundary layers  

NASA Technical Reports Server (NTRS)

The results of an experimental program to evaluate heat transfer and pressure distributions on corrugation roughened flat plates in thick turbulent boundary layers are presented. The experimental program consisted of tests in the tunnel wall boundary layers of the Langley Unitary Plan Wind Tunnel (UPWT) and Continuous Flow Hypersonic Tunnel (CFHT) at freestream Mach numbers of 2.5, 3.5, 4.5, and 10.3. Tests in the UPWT were conducted at a freestream Reynolds number/m of 10,800,000 and in the CFHT, at Reynolds numbers/m of 1,300,000 to 5,800,000. The test configurations consisted of 50.8 x 50.8 cm panels with corrugated beads of two different peak amplitudes, 0.61 and 0.29 cm. The angle of the corrugated beads relative to the flow direction was varied between 0 (aligned) and 90 deg (normal). The measured peak and average heat transfer are analyzed and correlated in terms of the bulk boundary layer, internal boundary layer, and geometric parameters.-

Brandon, H. J.; Masek, R. V.; Dunavant, J. C.

1975-01-01

390

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

391

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

PubMed Central

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

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

2007-01-01

392

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

393

Physics of heat pipe rewetting  

NASA Technical Reports Server (NTRS)

This is the final report which summarizes the research accomplishments under the project entitled 'Physics of Heat Pipe Rewetting' under NASA Grant No. NAG 9-525, Basic, during the period of April 1, 1991 to January 31, 1994. The objective of the research project was to investigate both analytically and experimentally the rewetting characteristics of the heated, grooved plate. The grooved plate is to simulate the inner surface of the vapor channel in monogroove heat pipes for space station design. In such designs, the inner surface of the vapor channel is threaded with monogrooves. When the heat pipe is thermally overloaded, dryout of the monogroove surface occurs. Such a dryout surface should be promptly rewetted to prevent the failure of the heat pipe operation in the thermal radiator of the space station.

Chan, S. H.

1994-01-01

394

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

395

Light pipes for LED measurements  

NASA Technical Reports Server (NTRS)

Light pipe directly couples LED optical output to single detector. Small area detector measures total optical output of diode. Technique eliminates thermal measurement problems and channels optical output to remote detector.

Floyd, S. R.; Thomas, E. F., Jr.

1976-01-01

396

Heat pipe radiators for space  

NASA Technical Reports Server (NTRS)

Analysis of the data heat pipe radiator systems tested in both vacuum and ambient environments was continued. The systems included (1) a feasibility VCHP header heat-pipe panel, (2) the same panel reworked to eliminate the VCHP feature and referred to as the feasibility fluid header panel, and (3) an optimized flight-weight fluid header panel termed the 'prototype.' A description of freeze-thaw thermal vacuum tests conducted on the feasibility VCHP was included. In addition, the results of ambient tests made on the feasibility fluid header are presented, including a comparison with analytical results. A thermal model of a fluid header heat pipe radiator was constructed and a computer program written. The program was used to make a comparison of the VCHP and fluid-header concepts for both single and multiple panel applications. The computer program was also employed for a parametric study, including optimum feeder heat pipe spacing, of the prototype fluid header.

Sellers, J. P.

1976-01-01

397

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

398

Lifetests of telecommunications satellite heat pipes  

Microsoft Academic Search

The life testing of low temperature heat pipes designed for satellite thermal control is discussed. Five stainless steel\\/ammonia artery heat pipes and four aluminum\\/ammonia artery heat pipes were operated at elevated temperatures of about 60 C with a heat load of 15 watts for each pipe. In addition, two axially grooved aluminum\\/ammonia heat pipes operating at 60 C with a

W. D. Muenzel

1979-01-01

399

Unsteady axial viscoelastic pipe flows  

Microsoft Academic Search

The main objective of this work is to examine in detail basic unsteady pipe flows and to investigate any new physical phenomena. We take the viscoelastic upper-convected Maxwell fluid as our non-Newtonian model and consider the flow of such a fluid in pipes of uniform circular cross-section in the following three cases: 1.(a) when the pressure gradient varies exponentially with

K. D. Rahaman; H. Ramkissoon

1995-01-01

400

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

401

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

402

Piping inspection round robin  

SciTech Connect

The piping inspection round robin was conducted in 1981 at the Pacific Northwest National Laboratory (PNNL) to quantify the capability of ultrasonics for inservice inspection and to address some aspects of reliability for this type of nondestructive evaluation (NDE). The round robin measured the crack detection capabilities of seven field inspection teams who employed procedures that met or exceeded the 1977 edition through the 1978 addenda of the American Society of Mechanical Engineers (ASME) Section 11 Code requirements. Three different types of materials were employed in the study (cast stainless steel, clad ferritic, and wrought stainless steel), and two different types of flaws were implanted into the specimens (intergranular stress corrosion cracks (IGSCCs) and thermal fatigue cracks (TFCs)). When considering near-side inspection, far-side inspection, and false call rate, the overall performance was found to be best in clad ferritic, less effective in wrought stainless steel and the worst in cast stainless steel. Depth sizing performance showed little correlation with the true crack depths.

Heasler, P.G.; Doctor, S.R. [Pacific Northwest National Lab., Richland, WA (United States)

1996-04-01

403

Organ pipe resonance induced vibration in piping system  

SciTech Connect

Acoustic-induced vibration is a fluid-structure interaction phenomenon. The feedback mechanism between the acoustic pressure pulsation and the structure movements determines the excited acoustic modes which, in turn, amplify the structure response when confidence frequency and mode shape matching occurs. The acoustic modes are not determined from the acoustic boundary conditions alone, structure feedback is as responsible for determining the acoustic modes and shaping the resulting forcing functions. Acoustic-induced piping vibration, when excited, does not attenuate much with distance. Pressure pulsation can be transmitted throughout the piping system and its branch connections. It is this property that makes vibration monitoring difficult, because vibration can surface at locations far away from the acoustic source when resonance occurs. For a large piping system with interconnected branches, the monitoring task can be formidable, particularly when there is no indication what the real source is. In organ pipe resonance induced vibration, the initiating acoustic source may be inconspicuous or unavoidable during operation. In these situations, the forcing function approach can offer an optimal tool for vibration assessment. The forcing function approach was used in the evaluation of a standby steam piping vibration problem. Monitoring locations and instrument specifications were determined from the acoustic eigenfunction profiles. Measured data confirmed the presence of coherent vibrations in the large bore piping. The developed forcing function permits design evaluation of the piping system, which leads to remedial actions and enables fatigue life determination, thus providing confidence to system operation. The forcing function approach is shown to be useful in finding potential vibration area and verifying the integrity of weak structure links. Application is to steam lines at BWR plants.

Wang, T.

1996-12-01

404

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

405

NEP heat pipe radiators. [Nuclear Electric Propulsion  

NASA Technical Reports Server (NTRS)

This paper covers improvements of heat pipe radiators for the thermionic NEP design. Liquid metal heat pipes are suitable as spacecraft radiator elements because of high thermal conductance, low mass and reliability, but the NEP thermionic system design was too large and difficult to fabricate. The current integral collector-radiator design consisting of several layers of thermionic converters, the annular-tangential collector heat pipe, the radiator heat pipe, and the transition zone designed to minimize the temperature difference between the collector heat pipe and radiator heat pipe are described. Finally, the design of micrometeoroid armor protection and the fabrication of the stainless steel annular heat pipe with a tangential arm are discussed, and it is concluded that the heat rejection system for the thermionic NEP system is well advanced, but the collector-radiator heat pipe transition and the 8 to 10 m radiator heat pipe with two bends require evaluation.

Ernst, D. M.

1979-01-01

406

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

407

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

408

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

409

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

SciTech Connect

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

Polycarpou, A. C. [Department of Electrical and Computer Engineering, University of Nicosia, 46, Makedonitissas Ave. P.O. Box 24005, 1700 Nicosia (Cyprus); Christou, M. A. [Department of Mathematics, University of Nicosia, 46, Makedonitissas Ave. P.O. Box 24005, 1700 Nicosia (Cyprus)

2011-11-29

410

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

NASA Astrophysics Data System (ADS)

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

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

2011-11-01

411

Disrupting the wall accumulation of human sperm cells by artificial corrugation  

E-print Network

Many self-propelled microorganisms are attracted to surfaces. This makes their dynamics in restricted geometries very different from that observed in the bulk. Swimming along walls is beneficial for directing and sorting cells, but may be detrimental if homogeneous populations are desired, such as in counting microchambers. In this work, we characterize the motion of human sperm cells $\\sim$60$\\mu$m long, strongly confined to $\\sim$20$\\mu$m shallow chambers. We investigate the nature of the cell trajectories between the confining surfaces and their accumulation near the borders. Observed cell trajectories are composed of a succession of quasi-circular and quasi-linear segments. This suggests that the cells follow a path of intermittent trappings near the top and bottom surfaces separated by stretches of quasi-free motion in between the two surfaces. We show that the introduction of artificial petal-shaped corrugation in the lateral boundaries limits the accumulation near the borders and contributes to increase the concentration in the chamber interior. The steady state limit is achieved over times of the order of minutes, which agrees well with a theoretical estimate based on the assumption that the cell mean-square displacement is largely due to the quasi-linear segments. Pure quasi-circular trajectories would require several hours to stabilize. Our predictions also indicate that stabilization proceeds 2.5 times faster in the corrugated chambers than in the non-corrugated ones, which is another practical reason to prefer the former for microfluidic applications in biomedicine.

H. A. Guidobaldi; Y. Jeyaram; C. A. Condat; M. Oviedo; I. Berdakin; V. V. Moshchalkov; L. C. Giojalas; A. V. Silhanek; V. I. Marconi

2015-01-07

412

46 CFR 56.30-3 - Piping joints (reproduces 110).  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Piping joints (reproduces 110). 56.30-3 Section 56...APPURTENANCES Selection and Limitations of Piping Joints § 56.30-3 Piping joints (reproduces 110). The type of piping...

2012-10-01

413

46 CFR 56.30-3 - Piping joints (reproduces 110).  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Piping joints (reproduces 110). 56.30-3 Section 56...APPURTENANCES Selection and Limitations of Piping Joints § 56.30-3 Piping joints (reproduces 110). The type of piping...

2013-10-01

414

46 CFR 56.30-3 - Piping joints (reproduces 110).  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Piping joints (reproduces 110). 56.30-3 Section 56...APPURTENANCES Selection and Limitations of Piping Joints § 56.30-3 Piping joints (reproduces 110). The type of piping...

2011-10-01

415

46 CFR 56.30-3 - Piping joints (reproduces 110).  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Piping joints (reproduces 110). 56.30-3 Section 56...APPURTENANCES Selection and Limitations of Piping Joints § 56.30-3 Piping joints (reproduces 110). The type of piping...

2010-10-01

416

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

417

24 CFR 3280.705 - Gas piping systems.  

Code of Federal Regulations, 2013 CFR

...B36.10-1979, Welded and Seamless Wrought Steel Pipe. Threaded brass pipe in iron...may be used. Threaded brass pipe shall comply with ASTM B43-91, Standard Specification for Seamless Red Brass Pipe, Standard Sizes....

2013-04-01

418

24 CFR 3280.705 - Gas piping systems.  

Code of Federal Regulations, 2014 CFR

...B36.10-1979, Welded and Seamless Wrought Steel Pipe. Threaded brass pipe in iron...may be used. Threaded brass pipe shall comply with ASTM B43-91, Standard Specification for Seamless Red Brass Pipe, Standard Sizes....

2014-04-01

419

24 CFR 3280.706 - Oil piping systems.  

Code of Federal Regulations, 2010 CFR

...Steel or wrought-iron pipe shall comply with ANSI B 36.10-1979, Welded and Seamless Wrought Steel Pipe. Threaded copper or brass pipe in iron pipe sizes may be used. ...Standard Specification for Seamless Copper Water Tube,...

2010-04-01

420

24 CFR 3280.706 - Oil piping systems.  

Code of Federal Regulations, 2014 CFR

...Steel or wrought-iron pipe shall comply with ANSI B 36.10-1979, Welded and Seamless Wrought Steel Pipe. Threaded copper or brass pipe in iron pipe sizes may be used. ...Standard Specification for Seamless Copper Water Tube,...

2014-04-01

421

24 CFR 3280.705 - Gas piping systems.  

Code of Federal Regulations, 2010 CFR

...B36.10-1979, Welded and Seamless Wrought Steel Pipe. Threaded brass pipe in iron...may be used. Threaded brass pipe shall comply with ASTM B43-91, Standard Specification for Seamless Red Brass Pipe, Standard Sizes....

2010-04-01

422

24 CFR 3280.706 - Oil piping systems.  

Code of Federal Regulations, 2011 CFR

...Steel or wrought-iron pipe shall comply with ANSI B 36.10-1979, Welded and Seamless Wrought Steel Pipe. Threaded copper or brass pipe in iron pipe sizes may be used. ...Standard Specification for Seamless Copper Water Tube,...

2011-04-01

423

24 CFR 3280.706 - Oil piping systems.  

Code of Federal Regulations, 2012 CFR

...Steel or wrought-iron pipe shall comply with ANSI B 36.10-1979, Welded and Seamless Wrought Steel Pipe. Threaded copper or brass pipe in iron pipe sizes may be used. ...Standard Specification for Seamless Copper Water Tube,...

2012-04-01

424

24 CFR 3280.706 - Oil piping systems.  

Code of Federal Regulations, 2013 CFR

...Steel or wrought-iron pipe shall comply with ANSI B 36.10-1979, Welded and Seamless Wrought Steel Pipe. Threaded copper or brass pipe in iron pipe sizes may be used. ...Standard Specification for Seamless Copper Water Tube,...

2013-04-01

425

24 CFR 3280.705 - Gas piping systems.  

Code of Federal Regulations, 2011 CFR

...B36.10-1979, Welded and Seamless Wrought Steel Pipe. Threaded brass pipe in iron...may be used. Threaded brass pipe shall comply with ASTM B43-91, Standard Specification for Seamless Red Brass Pipe, Standard Sizes....

2011-04-01

426

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

427

High performance flexible heat pipes  

NASA Technical Reports Server (NTRS)

A Phase I SBIR NASA program for developing and demonstrating high-performance flexible heat pipes for use in the thermal management of spacecraft is examined. The program combines several technologies such as flexible screen arteries and high-performance circumferential distribution wicks within an envelope which is flexible in the adiabatic heat transport zone. The first six months of work during which the Phase I contract goal were met, are described. Consideration is given to the heat-pipe performance requirements. A preliminary evaluation shows that the power requirement for Phase II of the program is 30.5 kilowatt meters at an operating temperature from 0 to 100 C.

Shaubach, R. M.; Gernert, N. J.

1985-01-01

428

Escape beam statistics and dynamical properties for a periodically corrugated waveguide  

NASA Astrophysics Data System (ADS)

Some escape and dynamical properties for a beam of light inside a corrugated waveguide are discussed by using Fresnel reflectance. The system is described by a mapping and is controlled by a parameter ? defining a transition from integrability (?=0) to non integrability (??0). The phase space is mixed containing periodic islands, chaotic seas and invariant tori. The histogram of escaping orbits is shown to be scaling invariant with respect to ?. The waveguide is immersed in a region with different refractive index. Different optical materials are used to overcame the results.

da Costa, Diogo Ricardo; Silva, Mário R.; Leonel, Edson D.

2014-04-01

429

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

430

Influence of corrugation shape in steel bars ductility used on reinforced concrete  

NASA Astrophysics Data System (ADS)

Necking process stress and strain analysis, which is key to determine the plastic flow evolution in finite deformation, has been widely studied and applied to a number of materials based on the theories established by Davidenkov-Spiridnova and Bridgman in the 40's decade. These theories envolve from the study of necking geometry in fracture. In this paper, we develop an exhaustive experimental analysis of the stress and strain field in the necking process, applied to concrete bars and mechanized samples with similar features, in order to compare the results with the ones given by the theories listed above and to look for the corrugation influence in the material's plastic behavior.

Hortigón, B.; Nieto, E. J.; Fernández, F.; Hernández, O.

2012-04-01

431

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

432

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

433

Superresolution observed from evanescent waves transmitted through nano-corrugated metallic films  

NASA Astrophysics Data System (ADS)

Plane EM waves transmitted through nano-corrugated metallic thin films produce evanescent waves which include the information on the nano-structures. The production of the evanescent waves at the metallic surface is analyzed. A microsphere located above the metallic surface collects the evanescent waves which are converted into propagating waves. The equations for the refraction at the boundary of the microsphere and the use of Snell's law for evanescent waves are developed. The magnification of the nano-structure images is explained by a geometric optics description, but the high resolution is related to the evanescent waves properties.

Ben-Aryeh, Y.

2012-10-01

434

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

435

46 CFR 154.660 - Pipe welding.  

Code of Federal Regulations, 2014 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...

2014-10-01

436

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

437

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

438

Dispersion relation and growth rate for a corrugated channel free-electron laser with a helical wiggler pump  

NASA Astrophysics Data System (ADS)

The effects of corrugated ion channels on electron trajectories and spatial growth rate for a free-electron laser with a one-dimensional helical wiggler have been investigated. Analysis of the steady-state electron trajectories is performed by solving the equations of motion. Our results show that the presence of a corrugated channel shifts the resonance frequency to smaller values of ion channel frequency. The sixth-order dispersion equation describing the coupling between the electrostatic beam mode and the electromagnetic mode has also been derived. The dispersion relation characteristic is analyzed in detail by numerical solution. Results show that the growth rate of instability in the presence of corrugated ion channels can be greatly enhanced relative to the case of an uniform ion channel.

Hasanbeigi, A.; Mehdian, H.

2013-07-01

439

(In preparation for submission to Physical Review Letters) Spontaneous nanoscale corrugation of ion-eroded SiO2 : the role of ion  

E-print Network

of ion-eroded SiO2 : the role of ion irradiation-enhanced viscous flow Christopher C. Umbach,1 Randall L-ray scattering was used to determine the temperature and ion-energy dependence of nanoscale corrugations that form on an amorphous SiO2 surface eroded by Ar+ ions. The corrugation wavelength * shows a nearly

Headrick, Randall L.

440

Optimizing pipe deformation in a reduction mill  

Microsoft Academic Search

The typical manufacturing technology for general- purpose pipe includes rolling and subsequent normal- ization with separate heating. This is associated with additional heating costs and relatively poor pipe perfor- mance. The use of thermomechanical treatment in the pro- duction of seamless pipe both reduces the cost and improves the mechanical properties. Accordingly, the introduction of this technology is a high

L. G. Marchenko

2008-01-01

441

The magnetic properties of seamless steel pipe  

Microsoft Academic Search

The magnetic and metallurgical properties of seamless pipe steel have been investigated as a function of position around the pipe circumference. No changes in magnetic properties were found to be associated with the four cycle spiral variations in pipe wall thickness introduced during forging. A weaker single cycle thickness variation was accompanied by a change both in magnetic properties and

S. N. M. Willcock; B. K. Tanner; P. A. Mundell

1987-01-01

442

NEUTRON STREAMING IN DâO PIPES  

Microsoft Academic Search

An investigation wae carried out concerning the attenuation of neutrons ; inside DâO-filled pipes penetrating a concrete shield. Pipes surrounded by ; an annular air gap were also considered. Thermal, epithermal, and fast neutron ; fluxes were raeasured in three separate pipes (15, 22, and 28 cm in diameter and ; 100 cm long) with annulii ranging from 0 to

J. Braun; K. Randen

1962-01-01

443

49 CFR 192.59 - Plastic pipe.  

Code of Federal Regulations, 2010 CFR

... 3 2010-10-01 2010-10-01 false Plastic pipe. 192.59 Section 192.59 Transportation...FEDERAL SAFETY STANDARDS Materials § 192.59 Plastic pipe. (a) New plastic pipe is qualified for use under this part...

2010-10-01

444

49 CFR 192.59 - Plastic pipe.  

Code of Federal Regulations, 2011 CFR

... 3 2011-10-01 2011-10-01 false Plastic pipe. 192.59 Section 192.59 Transportation...FEDERAL SAFETY STANDARDS Materials § 192.59 Plastic pipe. (a) New plastic pipe is qualified for use under this part...

2011-10-01

445

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

446

Transient heat pipe response and rewetting behavior  

Microsoft Academic Search

This paper describes the results of an investigation of pulsed heat pipe start up. Two types of pulsed start up of a copper and water heat pipe are examined. In the first, the mean temperature of the transport section is nearly constant with time. In the second, the entire heat pipe is increasing in temperature, so thermal energy storage is

J. H. Ambrose; L. C. Chow; J. E. Beam

1986-01-01

447

Development of a cryogenic heat pipe  

Microsoft Academic Search

Heat pipe operating characteristics can be used to advantage in cryogenic systems. Diode operation of the heat pipe, the ability to conduct heat in one direction only, is useful in protecting the heat load if the heat sink temperature rises above the load temperature. Because of this, the heat pipe can be made to act as a thermal switch. A

F. C. Prenger; W. F. Stewart; J. E. Runyan

1993-01-01

448

The THROHPUT code: Thermohydraulic heat pipe modeling  

Microsoft Academic Search

The THROHPUT code is a special purpose transient thermodynamic model of high temperature liquid-metal heat pipe response (THROHPUT is an acronym for Thermal Hydraulic Response Of Heat Pipes Under Transients). A special purpose code like THROHPUT is needed due to the complex nature and interconection of the physical processes occurring in the operation of a heat pipe with the working

Michael L. Hall; Joseph M. Doster

1988-01-01

449

49 CFR 195.424 - Pipe movement.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Pipe movement. 195.424 Section...Maintenance § 195.424 Pipe movement. (a) No operator may move any line pipe, unless the pressure in the...liquid state with continuous flow, but not less than 50...

2013-10-01

450

49 CFR 195.424 - Pipe movement.  

Code of Federal Regulations, 2014 CFR

...2014-10-01 2014-10-01 false Pipe movement. 195.424 Section...Maintenance § 195.424 Pipe movement. (a) No operator may move any line pipe, unless the pressure in the...liquid state with continuous flow, but not less than 50...

2014-10-01

451

49 CFR 195.424 - Pipe movement.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Pipe movement. 195.424 Section...Maintenance § 195.424 Pipe movement. (a) No operator may move any line pipe, unless the pressure in the...liquid state with continuous flow, but not less than 50...

2012-10-01

452

49 CFR 195.424 - Pipe movement.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Pipe movement. 195.424 Section...Maintenance § 195.424 Pipe movement. (a) No operator may move any line pipe, unless the pressure in the...liquid state with continuous flow, but not less than 50...

2011-10-01

453

Two-dimensional rotating heat pipe analysis  

Microsoft Academic Search

A detailed transient numerical simulation of rotating heat pipes is presented. This two-dimensional, axisymmetric formulation accounts for the thin liquid condensate film on the inner surface of the rotating pipe wall, the vapor flow in the vapor space, and the unsteady heat conduction in the pipe wall. The thin liquid film is coupled to the vapor velocity at the liquid-vapor

C. Harley; A. Faghri

1995-01-01

454

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

455

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

456

Calculate the heat loss from pipes  

Microsoft Academic Search

Heat lost from piped fluids is energy wasted. Even a fluid-temperature drop of 1 C or less from the pipe's inlet to its outlet is a sign of heat loss. This raises energy costs because heat must usually be added back to the fluid later. If the pipe-wall temperature is not unduly high, convection can be assumed to be the

Konak

1993-01-01

457

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

NASA Astrophysics Data System (ADS)

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 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

458

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

459

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

460

Heat pipe dynamics. Final report, April 30, 1981. [Uses of heat pipe, especially in solar collector  

SciTech Connect

A heat-pipe flat plate solar collector is constructed like a typical flat plate collector with the exception that individual heat pipes are attached to the collector surface to transfer collected heat via a phase change from collector surface into an attached jacket containing a phase change material. The efficiency of such a collector was measured roughly. Also briefly described are: a heat-pipe heat exchanger, heat-pipe heat exchanger freeze proofing, heat-pipe attic ventilation, transfer of light bulb heat via a heat pipe to heat water, heat recovery via heat pipe, cooling of oil in engines and transmissions via heat pipe, a tracking reflector, automatic sun tracker, single-stroke vacuum pump for heat-pipe manufacture, and heat pipe heat transfer from rock bed. (LEW)

Norman, R.M. Sr.

1981-01-01

461

Differential Strain Rate as a Mechanism for the Formation of Detachment-Fault Corrugations: A Case Study From Western Norway  

NASA Astrophysics Data System (ADS)

Transport-parallel corrugations on normal-sense detachment faults are described in extensional tectonic settings at the range through orogen scale. The mechanisms by which these corrugations form have implications for the original shape of the detachment fault, pre-existing basement structures, the formation and architecture of supra-detachment basins, and the overall tectonic setting of the orogenic event. Western Norway provides an ideal setting to investigate the formation of detachment-fault corrugations. There, the normal-sense Nordfjord-Sogn Detachment Zone--thought to be one of the primary structures responsible for exhuming the high- and ultrahigh-pressure rocks of the Western Gneiss Complex--is corrugated by a series of extension-parallel folds that deform footwall rocks, hanging-wall rocks, and muscovite chrontours. The largest of these corrugations displays a minimum fold amplitude of tectonostratigraphic layers of 5 km, and exposes muscovite cooling ages in the core of the antiform that are 10--15 Myr younger than the immediately adjacent synformal structures. Here, we suggest that the limbs of these corrugations represent transfer faults/shear zones between regions of differential exhumation that were localized by the density-driven ascent of the ultrahigh-pressure Western Gneiss Complex. The viability of this hypothesis was tested through a series of 2-D kinematic/finite-difference thermal models. Subducted lithosphere with an initially cold geotherm was allowed to exhume via a combination of pure-shear thinning and simple-shear removal of upper crust along a broad detachment zone, followed by conductive relaxation. The models indicate that even modest differences in exhumation rate (less than even 20 percent) create fold amplitudes within the tectonostratigraphy of up to 7 km, and produce 2--5 km offsets of the 400° isotherm (muscovite closure to Ar). These results are consistent with outcrop patterns and 10--15 Myr differences in muscovite cooling ages observed in Western Norway. This work has important implications for the geology of Western Norway, suggesting that the corrugations on the Nordfjord Sogn Detachment Zone may be the result of differential exhumation rather than orogen-scale constriction and transtension, and indicates that transfer faults/shear zones should be considered a viable mechanism for corrugated detachments in extensional settings worldwide.

Johnston, S. M.; Hacker, B.

2005-12-01

462

The Effects of Road Crossings on Prairie Stream Habitat and Function  

Microsoft Academic Search

Improperly designed stream crossing structures may alter the form and function of stream ecosystems and habitat and prohibit the movement of aquatic organisms. Stream sections adjoining five concrete box culverts, five low-water crossings (concrete slabs vented by one or multiple culverts), and two large, single corrugated culvert vehicle crossings in eastern Kansas streams were compared to reference reaches using a

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

2010-01-01

463

Forming of seamless pipe fittings  

Microsoft Academic Search

Analysis and results of the high temperature forming of seamless pipe fittings produced at a local factory are presented in this work. The studies were conducted by recording the thermal evolution in different parts of the piece as it was being forged, which was done by placing a series of type K thermocouples within the part and logging the data

Andrés Rodr??guez; Margarita Mezzetti; Peter Fodor; Rafael Colás

2002-01-01

464

Pipe Leak Detection Technology Development  

EPA Science Inventory

The U. S. Environmental Protection Agency (EPA) has determined that one of the nation?s biggest infrastructural needs is the replacement or rehabilitation of the water distribution and transmission systems. The institution of more effective pipe leak detection technology will im...

465

Modeling of pulsating heat pipes  

Microsoft Academic Search

This report summarizes the results of a computer model that describes the behavior of pulsating heat pipes (PHP). The purpose of the project was to develop a highly efficient (as compared to the heat transfer capability of solid copper) thermal groundplane (TGP) using silicon carbide (SiC) as the substrate material and water as the working fluid. The objective of this

Richard C. Givler; Mario J. Martinez

2009-01-01

466

Transient thermohydraulic heat pipe modeling  

Microsoft Academic Search

Many space based reactor designs employ heat pipes as a means of conveying heat. In these designs, thermal radiation is the principle means for rejecting waste heat from the reactor system, making it desirable to operate at high temperatures. Lithium is generally the working fluid of choice as it undergoes a liquid-vapor transformation at the preferred operating temperature. The nature

Michael L. Hall; Joseph M. Doster

1987-01-01

467

Welding HSLA line pipe steels  

Microsoft Academic Search

This paper has reviewed the various aspects of weldability as it is influenced by the base metal composition and processing in HSLA line pipe steels. The Mo-Nb steels meet these stringent weldability requirements. Consumables have been developed for both girth and seam welding the Mo-Nb steels, and the strength and toughness required for severe service can be obtained with consumables

J. M. Sawhill

1977-01-01

468

Pump assisted heat pipe system  

NASA Astrophysics Data System (ADS)

A laboratory model of a pump assisted heat pipe has been fabricated and tested in order to assess the potential for advanced thermal systems for future spacecraft. New arterial heat pipes with axial grooves and gear pump driven through a magnetic coupling have been developed for this purpose and two sets of heat pipe, 0.2 m and 1 m models, have been prepared. Component tests for the heat pipes have been carried out and its heat transfer characteristics, especially the dry-out phenomenon, are discussed. This system test revealed that the condition for stable operation without anomalous loop behavior can be established, and it is found that excess working fluid flow rate is needed in order to avoid dry-out at high heat flux condition. In the accumulator pressure test, it is seen that the thermal conductance of the condenser varies so as to keep the system vapor pressure same as that in the accumulator. This is due to liquid blockage in the condenser and it would provide an effective means of controlling temperature through the accumulator pressure regulated externally.

Miyazaki, Y.; Oshima, S.; Furukawa, M.; Imai, R.

1988-06-01

469

Traveling Waves in Pipe Flow  

Microsoft Academic Search

A family of three-dimensional traveling waves for flow through a pipe of circular cross section is identified. The traveling waves are dominated by pairs of downstream vortices and streaks. They originate in saddle-node bifurcations at Reynolds numbers as low as 1250. All states are immediately unstable. Their dynamical significance is that they provide a skeleton for the formation of a

Holger Faisstand; Bruno Eckhardt

2003-01-01

470

Magnetohydrodynamic pipe flow. Part 1  

Microsoft Academic Search

The solution is obtained to the problem of the steady onedimensional ; flow of an incompressible, viscous, electrically fluid through a circular pipe in ; the presence of an applied (transverse) uniform magnetic field. A no-slip ; condition on the velocity is assumed at the nonconducting wall. The solution is ; exact and thus valid for all values of the

Richard R. Gold

1962-01-01

471

Hydrogen Piping Experience in Chevron  

E-print Network

experienced engineers Many of our practices such as bridge welding are effectively aimed at preventing fatigue commonly SA 333 Gr6); may call for A672 (specific grades) electric-fusion-welded pipe for sizes >16" 100% radiographic examination required for all welds Postweld Heat Treatment requirements as a function of thickness

472

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

PubMed

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

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

2014-01-01

473

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

PubMed Central

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

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

2014-01-01

474

Interaction of an ultrashort laser pulse and relativistic electron beam in a corrugated plasma channel  

SciTech Connect

Copropagation of a laser pulse and a relativistic electron beam in a corrugated plasma channel has been proposed for the direct laser acceleration of electrons [Palastro et al., Phys. Rev. E 77, 036405 (2008)]. The corrugated plasma channel allows for the guiding of laser pulses composed of subluminal spatial harmonics. Phase matching between the electron beam and the spatial harmonics results in acceleration, but for high beam densities, the pulse energy can be rapidly depleted. This depletion may result in interaction times shorter than the waveguide length limited time or pulse length dephasing time. We present an analytic model and self-consistent simulations of the electron beam-laser pulse interaction. A linear dispersion relation is derived. The effect of the electron beam on the pulse after the occurrence of axial bunching is examined. Injection of axially modulated electron beams is also explored. In particular, we find that a properly phased electron beam can transfer energy to the laser pulse as an inverse process to acceleration.

Palastro, J. P.; Antonsen, T. M. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742 (United States)

2009-07-15

475

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

SciTech Connect

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, André; Vervier, Michel [LPP-ERM/KMS, EURATOM-Belgian State Association, TEC partner, B-1000 Brussels (Belgium)

2014-02-12

476

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

SciTech Connect

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

Minami, K.; Ogura, K.; Kurashina, K; Kim, W. [Niigata Univ. (Japan). Dept. of Electrical Engineering; Watanabe, Tsuguhiro [National Inst. for Fusion Research, Nagoya (Japan); Carmel, Y.; Destler, W.W.; Granatstein, V.L. [Univ. of Maryland, College Park, MD (United States). Inst. for Plasma Research

1994-12-31

477

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, André; Vervier, Michel

2014-02-01

478

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

SciTech Connect

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

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

2008-10-30

479

Design and Fabrication of a Ring-Stiffened Graphite-Epoxy Corrugated Cylindrical Shell  

NASA Technical Reports Server (NTRS)

Design and fabrication of supplement test panels that represent key portions of the cylinder are described, as are supporting tests of coupons, sample joints, and stiffening ring elements. The cylindrical shell is a ring-stiffened, open corrugation design that uses T300/5208 graphite-epoxy tape as the basic material for the shell wall and stiffening rings. The test cylinder is designed to withstand bending loads producing the relatively low maximum load intensity in the shell wall of 1,576 N/cm. The resulting shell wall weight, including stiffening rings and fasteners, is 0.0156 kg/m. The shell weight achieved in the graphite-epoxy cylinder represents a weight saving of approximately 23 percent, compared to a comparable aluminum shell. A unique fabrication approach was used in which the cylinder wall was built in three flat segments, which were then wrapped to the cylindrical shape. Such an approach, made possible by the flexibility of the thin corrugated wall in a radial direction, proved to be a simple approach to building the test cylinder. Based on tooling and fabrication methods in this program, the projected costs of a production run of 100 units are reported.

Johnson, R., Jr.

1978-01-01

480

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

481

Arterial and grooved cryogenic heat pipes.  

NASA Technical Reports Server (NTRS)

Tests were conducted on two cryogenic heat pipes using nitrogen as the working fluid. Both pipes are 1.27 cm in diameter. The first pipe is 141 cm long and uses longitudinal grooves in the aluminum wall as the wick structure. The second pipe is 91 cm long and has an arterial wick adjacent to the wall. In addition, circumferential screw threads are machined along the entire length of the inside pipe wall. Both heat pipes primed with no difficulty in the horizontal position. Start-up after burn-out was obtained repeatedly. However, more testing is required to determine whether the artery pipe is as reliable as the grooved pipe with respect to priming. Once primed, the artery heat pipe is much less sensitive to elevation than the grooved design and, consequently, offers a significant advantage with respect to ground testing. Heat-transfer characteristics of the two pipes were comparable, with both pipes achieving the initial goal of 1000 watt-cm of heat-transport capability.

Brennan, P.; Trimmer, D.; Sherman, A.; Cygnarowicz, T.

1971-01-01

482

Integrity of steel pipe during reeling  

SciTech Connect

An assessment of defect significance, with respect to fracture and plastic collapse, in parent pipe and girth welds in seamless 16in OD x 25mm WT pipe to API 5L X52 is described. Fracture mechanics (CTOD) resistance curve tests were conducted on parent pipe, cellulosic girth weld metal and HAZ. BSI PD6493 Level 3 analyses were conducted to assess the significance of potential flaws when the pipe is subjected to plastic strains of up to 2.4%, as experienced during the pipe reeling process (i.e. reeling and unreeling). The safety in the predicted flaw sizes was assessed against full scale bend tests on pipe containing artificial flaws and subjected to simulated pipe reeling. Despite the high strains involved, the predicted flaw sizes to avoid failure were conservative but realistic. It is shown that during service (when longitudinal stresses of up to 72% SMYS may be applied) flaws of the maximum predicted size will remain stable.

Pisarski, H.G.; Phaal, R.; Hadley, I. [TWI, Cambridge (United Kingdom). Dept. of Engineering; Francis, R. [Stena Offshore Ltd., Aberdeen (United Kingdom)

1994-12-31

483

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

484

Enhancement In Thermal Performance Of Solar Pond With Corrugated Bottom By Extracting Heat From Lower Convective Zone  

Microsoft Academic Search

The heat extraction from the lower convective zone or storage zone of salinity gradient solar pond with corrugated bottom is investigated with the aim of increasing the overall efficiency of collecting solar radiation, storing heat and delivering this heat to different applications. The energy balance equations for each zone have been used to develop the expression of temperature distribution in

U. K. SINHA; S. P. SHARMA; S. B. L. SEKSENA

485

Atomic scale study of corrugating and anticorrugating states on the bare Si(1?0?0) surface  

NASA Astrophysics Data System (ADS)

In this article, we study the origin of the corrugating and anticorrugating states through the electronic properties of the Si(1?0?0) surface via a low-temperature (9 K) scanning tunneling microscope (STM). Our study is based on the analysis of the STM topographies corrugation variations when related to the shift of the local density of states (LDOS) maximum in the [1 \\bar{{1}} 0] direction. Our experimental results are correlated with numerical simulations using the density-functional theory with hybrid Heyd–Scuseria–Ernzerhof (HSE06) functional to simulate the STM topographies, the projected density of states variations at different depths in the silicon surface as well as the three dimensional partial charge density distributions in real-space. This work reveals that the Si(1?0?0) surface exhibits two anticorrugating states at +0.8 and +2.8 V that are associated with a phase shift of the LDOS maximum in the unoccupied states STM topographies. By comparing the calculated data with our experimental results, we have been able to identify the link between the variations of the STM topographies corrugation and the shift of the LDOS maximum observed experimentally. Each surface voltage at which the STM topographies corrugation drops is defined as anticorrugating states. In addition, we have evidenced a sharp jump in the tunnel current when the second LDOS maximum shift is probed, whose origin is discussed and associated with the presence of Van Hove singularities.

Yengui, Mayssa; Pinto, Henry P.; Leszczynski, Jerzy; Riedel, Damien

2015-02-01

486

Atomic scale study of corrugating and anticorrugating states on the bare Si(1?0?0) surface.  

PubMed

In this article, we study the origin of the corrugating and anticorrugating states through the electronic properties of the Si(1?0?0) surface via a low-temperature (9 K) scanning tunneling microscope (STM). Our study is based on the analysis of the STM topographies corrugation variations when related to the shift of the local density of states (LDOS) maximum in the [Formula: see text] direction. Our experimental results are correlated with numerical simulations using the density-functional theory with hybrid Heyd-Scuseria-Ernzerhof (HSE06) functional to simulate the STM topographies, the projected density of states variations at different depths in the silicon surface as well as the three dimensional partial charge density distributions in real-space. This work reveals that the Si(1?0?0) surface exhibits two anticorrugating states at +0.8 and +2.8 V that are associated with a phase shift of the LDOS maximum in the unoccupied states STM topographies. By comparing the calculated data with our experimental results, we have been able to identify the link between the variations of the STM topographies corrugation and the shift of the LDOS maximum observed experimentally. Each surface voltage at which the STM topographies corrugation drops is defined as anticorrugating states. In addition, we have evidenced a sharp jump in the tunnel current when the second LDOS maximum shift is probed, whose origin is discussed and associated with the presence of Van Hove singularities. PMID:25524935

Yengui, Mayssa; Pinto, Henry P; Leszczynski, Jerzy; Riedel, Damien

2015-02-01

487

Wet-sand impulse loading of metallic plates and corrugated core sandwich panels J.J. Rimoli a  

E-print Network

Wet-sand impulse loading of metallic plates and corrugated core sandwich panels J.J. Rimoli a , B 2011 Available online 30 May 2011 Keywords: Sandwich panels Blast loading Impulse mitigation a b s t r from impulsive loading. The performance and advantages of sandwich panel construction have been

Wadley, Haydn

488

Dual manifold heat pipe evaporator  

DOEpatents

An improved evaporator section is described for a dual manifold heat pipe. Both the upper and lower manifolds can have surfaces exposed to the heat source which evaporate the working fluid. The tubes in the tube bank between the manifolds have openings in their lower extensions into the lower manifold to provide for the transport of evaporated working fluid from the lower manifold into the tubes and from there on into the upper manifold and on to the condenser portion of the heat pipe. A wick structure lining the inner walls of the evaporator tubes extends into both the upper and lower manifolds. At least some of the tubes also have overflow tubes contained within them to carry condensed working fluid from the upper manifold to pass to the lower without spilling down the inside walls of the tubes. 1 figure.

Adkins, D.R.; Rawlinson, K.S.

1994-01-04

489

Axially grooved heat pipes - 1976  

NASA Technical Reports Server (NTRS)

This paper summarizes the 'state-of-the-art' of axially grooved heat pipes. Applications are identified and the related heat pipe design and performance are defined. Recent developments in the analysis, design and fabrication of axially grooved hardware are also discussed. A mathematical model which predicts the hydrodynamic behavior and accounts for liquid recession, liquid/vapor shear interaction and 1-g puddle flow is also presented. Performance data for various fluids in the 100-500 K range is compared to predictions from the Groove Analysis Program (GAP). Finally, a simplified closed form solution which accounts for gravity effects, self-priming and composite pumping by the grooves as well as all of the hydrodynamic losses is also discussed.

Brennan, P. J.; Kroliczek, E. J.; Jen, H.; Mcintosh, R.

1977-01-01

490

Growth of InP directly on Si by corrugated epitaxial lateral overgrowth  

NASA Astrophysics Data System (ADS)

In an attempt to achieve an InP–Si heterointerface, a new and generic method, the corrugated epitaxial lateral overgrowth (CELOG) technique in a hydride vapor phase epitaxy reactor, was studied. An InP seed layer on Si (0?0?1) was patterned into closely spaced etched mesa stripes, revealing the Si surface in between them. The surface with the mesa stripes resembles a corrugated surface. The top and sidewalls of the mesa stripes were then covered by a SiO2 mask after which the line openings on top of the mesa stripes were patterned. Growth of InP was performed on this corrugated surface. It is shown that growth of InP emerges selectively from the openings and not on the exposed silicon surface, but gradually spreads laterally to create a direct interface with the silicon, hence the name CELOG. We study the growth behavior using growth parameters. The lateral growth is bounded by high index boundary planes of {3?3?1} and {2?1?1}. The atomic arrangement of these planes, crystallographic orientation dependent dopant incorporation and gas phase supersaturation are shown to affect the extent of lateral growth. A lateral to vertical growth rate ratio as large as 3.6 is achieved. X-ray diffraction studies confirm substantial crystalline quality improvement of the CELOG InP compared to the InP seed layer. Transmission electron microscopy studies reveal the formation of a direct InP–Si heterointerface by CELOG without threading dislocations. While CELOG is shown to avoid dislocations that could arise due to the large lattice mismatch (8%) between InP and Si, staking faults could be seen in the layer. These are probably created by the surface roughness of the Si surface or SiO2 mask which in turn would have been a consequence of the initial process treatments. The direct InP–Si heterointerface can find applications in high efficiency and cost-effective Si based III–V semiconductor multijunction solar cells and optoelectronics integration.

Metaferia, Wondwosen; Kataria, Himanshu; Sun, Yan-Ting; Lourdudoss, Sebastian

2015-02-01

491

Calculator solves pipe flow problems  

Microsoft Academic Search

For facilitating pipe-flow calculations that involve the horizontal flow of constant-density fluids, a simple program tailored to the TI-59 hand-held calculator uses the Darcy pressure-drop formula (modified for expressing the friction factor) to compute the unknown parameter needed to solve the fluid problem. Instead of several friction-factor equations applicable only in the individual flow regimes, the program uses a single,

1980-01-01

492

High-gain wide-band gyrotron traveling wave amplifier with a helically corrugated waveguide  

PubMed

First bandwidth measurements of a novel gyrotron amplifier are presented. The coupling between the second harmonic cyclotron mode of a gyrating electron beam and the radiation field occurred in the region of near infinite phase velocity over a broad bandwidth by using a cylindrical waveguide with a helical corrugation on its internal surface. With a beam energy of 185 keV, the amplifier achieved a maximum output power of 1.1 MW, saturated gain of 37 dB, linear gain of 47 dB, saturated bandwidth of 8.4 to 10.4 GHz ( 21% relative bandwidth), and an efficiency of 29%, in good agreement with theory. PMID:11017315

Bratman; Cross; Denisov; He; Phelps; Ronald; Samsonov; Whyte; Young

2000-03-20

493

Comparison of finite source and plane wave scattering from corrugated surfaces  

NASA Technical Reports Server (NTRS)

The choice of a plane wave to represent incident radiation in the analysis of scatter from corrugated surfaces was examined. The physical optics solution obtained for the scattered fields due to an incident plane wave was compared with the solution obtained when the incident radiation is produced by a source of finite size and finite distance from the surface. The two solutions are equivalent if the observer is in the far field of the scatterer and the distance from observer to scatterer is large compared to the radius of curvature at the scatter points, condition not easily satisfied with extended scatterers such as rough surfaces. In general, the two solutions have essential differences such as in the location of the scatter points and the dependence of the scattered fields on the surface properties. The implication of these differences to the definition of a meaningful radar cross section was examined.

Levine, D. M.

1977-01-01

494

Focusing radially polarized light by a concentrically corrugated silver film without a hole.  

PubMed

We report a phenomenon of focusing a radially polarized beam from the visible range by a silver film with no hole on the optical axis and double-sided concentric corrugations. The axes of symmetry of grooves and the illuminating beam coincide. An Ag lens of 100 nm thickness, five grooves, of which the outermost has 5 microm diameter, at lambda=400 nm transmits 22% of electric energy and focuses light into a 0.2lambda2 spot area at a focal length close to 2lambda, while at lambda=500 nm the results are 11%, 0.16lambda2 and lambda, respectively. This Ag lens focuses without contribution of evanescent waves a far-field source into a far-field spot. The nanolens acts like a refractive optical system of high numerical aperture close to unity. PMID:19518872

Wróbel, Piotr; Pniewski, Jacek; Antosiewicz, Tomasz J; Szoplik, Tomasz

2009-05-01

495

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

496

Sample corrugation affects the apparent bond lengths in atomic force microscopy.  

PubMed

Frequency modulation atomic force microscopy (AFM) allows the chemical structure of planar molecules to be determined with atomic resolution. Typically, these measurements are carried out in constant-height mode using carbon monoxide (CO) terminated tips. Such tips exhibit considerable flexibility, i.e., the CO molecule can bend laterally due to the tip-sample interaction. Using epitaxial graphene as a model system, we demonstrate experimentally that the apparent atomic positions measured by AFM depend on the sample corrugation. Using molecular mechanics simulations, we explain these observations by the interplay of the CO bending and the nonlinear background signal arising from the neighboring atoms. These effects depend nontrivially on the tip-sample distance and limit the achievable accuracy on the bond length determination based on AFM experiments. PMID:24559211

Boneschanscher, Mark P; Hämäläinen, Sampsa K; Liljeroth, Peter; Swart, Ingmar

2014-03-25

497

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

NASA Astrophysics Data System (ADS)

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.

Huang, Xu; Liang, Wentao; Zhang, Sulin

2011-12-01

498

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

NASA Astrophysics Data System (ADS)

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.

Huang, Xu; Liang, Wentao; Zhang, Sulin

2010-12-01

499

Energy shift of collective electron excitations in highly corrugated graphitic nanostructures: Experimental and theoretical investigation  

SciTech Connect

Effect of corrugation of hexagonal carbon network on the collective electron excitations has been studied using optical absorption and X-ray photoelectron spectroscopy in conjunction with density functional theory calculations. Onion-like carbon (OLC) was taken as a material, where graphitic mantle enveloping agglomerates of multi-shell fullerenes is strongly curved. Experiments showed that positions of ? and ??+?? plasmon modes as well as ? ? ?* absorption peak are substantially redshifted for OLC as compared with those of highly ordered pyrolytic graphite and thermally exfoliated graphite consisted of planar sheets. This effect was reproduced in behavior of dielectric functions of rippled graphite models calculated within the random phase approximation. We conclude that the energy of electron excitations in graphitic materials could be precisely tuned by a simple bending of hexagonal network without change of topology. Moreover, our investigation suggests that in such materials optical exciton can transfer energy to plasmon non-radiatively.

Sedelnikova, O. V., E-mail: o.sedelnikova@gmail.com; Bulusheva, L. G.; Okotrub, A. V. [Nikolaev Institute of Inorganic Chemistry, Siberian Branch of Russian Academy of Science, 3 Acad. Lavrentiev Ave., Novosibirsk 630090 (Russian Federation); Novosibirsk State University, 2 Pirogov Str., Novosibirsk 630090 (Russian Federation); Tomsk State University, 36 Lenina Ave., Tomsk 634050 (Russian Federation); Asanov, I. P. [Nikolaev Institute of Inorganic Chemistry, Siberian Branch of Russian Academy of Science, 3 Acad. Lavrentiev Ave., Novosibirsk 630090 (Russian Federation); Novosibirsk State University, 2 Pirogov Str., Novosibirsk 630090 (Russian Federation); Yushina, I. V. [Nikolaev Institute of Inorganic Chemistry, Siberian Branch of Russian Academy of Science, 3 Acad. Lavrentiev Ave., Novosibirsk 630090 (Russian Federation)

2014-04-21

500

Energy shift of collective electron excitations in highly corrugated graphitic nanostructures: Experimental and theoretical investigation  

NASA Astrophysics Data System (ADS)

Effect of corrugation of hexagonal carbon network on the collective electron excitations has been studied using optical absorption and X-ray photoelectron spectroscopy in conjunction with density functional theory calculations. Onion-like carbon (OLC) was taken as a material, where graphitic mantle enveloping agglomerates of multi-shell fullerenes is strongly curved. Experiments showed that positions of ? and ? + ? plasmon modes as well as ? ? ?* absorption peak are substantially redshifted for OLC as compared with those of highly ordered pyrolytic graphite and thermally exfoliated graphite consisted of planar sheets. This effect was reproduced in behavior of dielectric functions of rippled graphite models calculated within the random phase approximation. We conclude that the energy of electron excitations in graphitic materials could be precisely tuned by a simple bending of hexagonal network without change of topology. Moreover, our investigation suggests that in such materials optical exciton can transfer energy to plasmon non-radiatively.

Sedelnikova, O. V.; Bulusheva, L. G.; Asanov, I. P.; Yushina, I. V.; Okotrub, A. V.

2014-04-01