Science.gov

Sample records for electrically small cylinder

  1. Static imaging of the electrical impedance tomography on cylinder physical phantom.

    PubMed

    Liu, Ruigang; Fu, Feng; You, Fusheng; Shi, Xuetao; Dong, Xiuzhen

    2015-01-01

    Static imaging of the electrical impedance tomography can obtain the absolute electrical conductivity distribution at one section of the subject. The test is performed on a cylinder physical phantom in which slim rectangle, hollow cylinder, small rectangle or three cylinders are selected to simulate complex conductivity perturbation objects. The measurement data is obtained by a data acquisition system with 32 compound electrodes. A group of static images of conductivity distribution in the cylinder phantom are reconstructed by the modified Newton-Raphson algorithm with two kinds of regularization methods. The results show correct position, size, conductivity difference, and similar shape of the perturbation objects in the images.

  2. Assembly for electrical conductivity measurements in the piston cylinder device

    DOEpatents

    Watson, Heather Christine [Dublin, CA; Roberts, Jeffrey James [Livermore, CA

    2012-06-05

    An assembly apparatus for measurement of electrical conductivity or other properties of a sample in a piston cylinder device wherein pressure and heat are applied to the sample by the piston cylinder device. The assembly apparatus includes a body, a first electrode in the body, the first electrode operatively connected to the sample, a first electrical conductor connected to the first electrode, a washer constructed of a hard conducting material, the washer surrounding the first electrical conductor in the body, a second electrode in the body, the second electrode operatively connected to the sample, and a second electrical conductor connected to the second electrode.

  3. Sensitivity analysis of small circular cylinders as wake control

    NASA Astrophysics Data System (ADS)

    Meneghini, Julio; Patino, Gustavo; Gioria, Rafael

    2016-11-01

    We apply a sensitivity analysis to a steady external force regarding control vortex shedding from a circular cylinder using active and passive small control cylinders. We evaluate the changes on the flow produced by the device on the flow near the primary instability, transition to wake. We numerically predict by means of sensitivity analysis the effective regions to place the control devices. The quantitative effect of the hydrodynamic forces produced by the control devices is also obtained by a sensitivity analysis supporting the prediction of minimum rotation rate. These results are extrapolated for higher Reynolds. Also, the analysis provided the positions of combined passive control cylinders that suppress the wake. The latter shows that these particular positions for the devices are adequate to suppress the wake unsteadiness. In both cases the results agree very well with experimental cases of control devices previously published.

  4. The impulsive motion of a small cylinder at an interface

    NASA Astrophysics Data System (ADS)

    Vella, Dominic; Li, Jie

    2010-05-01

    We study the unsteady motion caused by an impulse acting at time t =0 on a small cylinder floating horizontally at a liquid-gas interface. This is a model for the impact of a cylinder onto a liquid surface after the initial splash. Following the impulse, the motion of the cylinder is determined by its weight per unit length (pulling it into the bulk liquid) and resistance from the liquid, which acts to keep the cylinder at the interface. The range of cylinder radii r and impact speeds U considered is such that the resistance from the liquid comes from both the interfacial tension and hydrodynamic pressures. We use two theoretical approaches to investigate this problem. In the first, we apply the arbitrary Lagrangian Eulerian (ALE) method developed by Li et al. ["An arbitrary Lagrangian Eulerian method for moving-boundary problems and its application to jumping over water," J. Comput. Phys. 208, 289 (2005)] to compute the fluid flow caused by the impulse and the (coupled) motion of the cylinder. We show that at early times the interfacial deformation is given by a family of shapes parametrized by r /t2/3. We also find that for a given density and radius there is a critical impulse speed below which the cylinder is captured by the interface and floats but above which it pierces the interface and sinks. Our second theoretical approach is a simplified one in which we assume that the interface is in equilibrium and derive an ordinary differential equation for the motion of the cylinder. Solving this we again find the existence of a critical impulse speed for sinking giving us some quantitative understanding of the results from the ALE simulations. Finally, we compare our theoretical predictions with the results of experiments for cylinder impacts by Vella and Metcalfe ["Surface tension dominated impact," Phys. Fluids 19, 072108 (2007)]. This comparison suggests that the influence of contact line effects, neglected here, may be important in the transition from floating

  5. 49 CFR 178.61 - Specification 4BW welded steel cylinders with electric-arc welded longitudinal seam.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Specification 4BW welded steel cylinders with... steel cylinders with electric-arc welded longitudinal seam. (a) Type, size and service pressure. A DOT 4BW cylinder is a welded type steel cylinder with a longitudinal electric-arc welded seam, a...

  6. 49 CFR 178.61 - Specification 4BW welded steel cylinders with electric-arc welded longitudinal seam.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Specification 4BW welded steel cylinders with... steel cylinders with electric-arc welded longitudinal seam. (a) Type, size and service pressure. A DOT 4BW cylinder is a welded type steel cylinder with a longitudinal electric-arc welded seam, a...

  7. 49 CFR 178.61 - Specification 4BW welded steel cylinders with electric-arc welded longitudinal seam.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Specification 4BW welded steel cylinders with... steel cylinders with electric-arc welded longitudinal seam. (a) Type, size and service pressure. A DOT 4BW cylinder is a welded type steel cylinder with a longitudinal electric-arc welded seam, a...

  8. 49 CFR 178.61 - Specification 4BW welded steel cylinders with electric-arc welded longitudinal seam.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Specification 4BW welded steel cylinders with... steel cylinders with electric-arc welded longitudinal seam. (a) Type, size and service pressure. A DOT 4BW cylinder is a welded type steel cylinder with a longitudinal electric-arc welded seam, a...

  9. Quantum phase transition in ultra small doubly connected superconducting cylinders

    NASA Astrophysics Data System (ADS)

    Sternfeld, I.; Koret, R.; Shtrikman, H.; Tsukernik, A.; Karpovski, M.; Palevski, A.

    2008-02-01

    The kinetic energy of Cooper pairs, in doubly connected superconducting cylinders, is a function of the applied flux and the ratio between the diameter of the cylinder and the zero temperature coherence length d/ ξ(0). If d >ξ(0) the known Little-Parks oscillations are observed. On the other hand if d <ξ(0), the superconducting state is energetically not favored around odd multiples of half flux quanta even at T∼0, resulting in the so called destructive regime [Y. Liu, et al., Science 294 (2001) 2332]. We developed a novel technique to fabricate superconducting doubly connected nanocylinders with both diameter and thickness less than 100 nm, and performed magnetoresistance measurements on such Nb and Al cylinders. In the Nb cylinders, where d >ξ(0), we observed the LP oscillations. In the Al cylinders we did not observe a transition to the superconducting state due to the proximity effect, resulted from an Au layer coating the Al. However, we did observe Altshuler-Aronov-Spivak (h/2e) oscillations in these cylinders.

  10. Plasma rotation by electric and magnetic fields in a discharge cylinder

    NASA Technical Reports Server (NTRS)

    Wilhelm, H. E.; Hong, S. H.

    1977-01-01

    A theoretical model for an electric discharge consisting of a spatially diverging plasma sustained electrically between a small ring cathode and a larger ring anode in a cylindrical chamber with an axial magnetic field is developed to study the rotation of the discharge plasma in the crossed electric and magnetic fields. The associated boundary-value problem for the coupled partial differential equations which describe the electric potential and the plasma velocity fields is solved in closed form. The electric field, current density, and velocity distributions are discussed in terms of the Hartmann number and the Hall coefficient. As a result of Lorentz forces, the plasma rotates with speeds as high as 1 million cm/sec around its axis of symmetry at typical conditions. As an application, it is noted that rotating discharges of this type could be used to develop a high-density plasma-ultracentrifuge driven by j x B forces, in which the lighter (heavier) ion and atom components would be enriched in (off) the center of the discharge cylinder.

  11. Interferometric investigations of convection around cylinders at small Grashof numbers.

    PubMed

    Crescentini, L; Fiocco, G

    1990-04-01

    Experiments with a Twyman-Green interferometer have been carried out to determine the temperature distribution around a horizontal cylinder in the presence of natural convection for Grashof numbers around 10(-4) and a Prandtl number of 0.7, a region of parameters poorly covered by previous investigations. Temperature differences are recovered by digital analysis of the fringe pattern perturbation. The results indicate significant discrepancies in the temperature profile, when compared with numerical models.

  12. 49 CFR 178.61 - Specification 4BW welded steel cylinders with electric-arc welded longitudinal seam.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... DOT 4BW cylinder is a welded type steel cylinder with a longitudinal electric-arc welded seam, a water... a maximum wall stress of 24,000 p.s.i. in the formula described in paragraph (f)(4) of this section... weldable steel, the carbon content of which may not exceed 0.25 percent. (f) Wall thickness. For...

  13. Compact Analytic Expression for the Electric Field of a 2DElliptical Charge Distribution Inside a Perfectly Conducting CircularCylinder

    SciTech Connect

    Furman, M.A.

    2007-05-29

    By combining the method of images with calculus of complex variables, we provide a simple expression for the electric field of a two-dimensional (2D) static elliptical charge distribution inside a perfectly conducting cylinder. The charge distribution need not be concentric with the cylinder.

  14. Kinetic pathways of sphere-to-cylinder transition in diblock copolymer melt under electric field.

    PubMed

    Ly, D Q; Pinna, M; Honda, T; Kawakatsu, T; Zvelindovsky, A V M

    2013-02-21

    Phase transition from body-centered-cubic spheres to cylinders in a diblock copolymer melt under an external electric field is investigated by means of real-space dynamical self-consistent field theory. Different phase transition kinetic pathways and different cylindrical domains arrangements of the final phase are observed depending on the strength and direction of the applied electric field. Various transient states have been identified depending on the electric field being applied along [111], [100], and [110] directions. The electric field should be above a certain threshold value in order the transition to occur. A "dynamic critical exponent" of the transition is found to be about 3/2, consistent with other order-order transitions in diblock copolymers under electric field.

  15. Electrically small, complementary electric-field-coupled resonator antennas

    NASA Astrophysics Data System (ADS)

    Odabasi, H.; Teixeira, F. L.; Guney, D. O.

    2013-02-01

    We study the radiation properties of electrically small resonant antennas (ka <1) composed of electric-field-coupled (ELC) and complementary electric-field-coupled (CELC) resonators and a monopole antenna. We use such parasitic ELC and CELC "metaresonators" to design various electrically small antennas. In particular, monopole-excited and bent-monopole-excited CELC resonator antennas are proposed that provide very low profiles on the order of λ0/20. We compare the performance of the proposed ELC and CELC antennas against more conventional designs based upon split-ring resonators.

  16. Heat transfer to small horizontal cylinders immersed in a fluidized bed

    SciTech Connect

    Friedman, J.; Koundakjian, P.; Naylor, D.; Rosero, D.

    2006-10-15

    Heat transfer to horizontal cylinders immersed in fluidized beds has been extensively studied, but mainly in the context of heat transfer to boiler tubes in coal-fired beds. As a result, most correlations in the literature have been derived for cylinders of 25-50 mm diameter in vigorously fluidizing beds. In recent years, fluidized bed heat treating furnaces fired by natural gas have become increasingly popular, particularly in the steel wire manufacturing industry. These fluidized beds typically operate at relatively low fluidizing rates and with small diameter wires (1-6 mm). Nusselt number correlations developed based on boiler tube studies do not extrapolate down to these small size ranges and low fluidizing rates. In order to obtain reliable Nusselt number data for these size ranges, an experimental investigation has been undertaken using two heat treating fluidized beds; one a pilot-scale industrial unit and the other a lab-scale (300 mm diameter) unit. Heat transfer measurements were obtained using resistively heated cylindrical samples ranging from 1.3 to 9.5 mm in diameter at fluidizing rates ranging from approximately 0.5 x G{sub mf} (packed bed condition) to over 10 x G{sub mf} using aluminum oxide sand particles ranging from d{sub p}=145-330 {mu}m (50-90 grit). It has been found that for all cylinder sizes tested, the Nusselt number reaches a maximum near 2 x G{sub mf}, then remains relatively steady ({+-}5-10%) to the maximum fluidizing rate tested, typically 8-12xG{sub mf}. A correlation for maximum Nusselt number is developed.

  17. Drag force and transport property of a small cylinder in free molecule flow: A gas-kinetic theory analysis

    NASA Astrophysics Data System (ADS)

    Liu, Changran; Li, Zhigang; Wang, Hai

    2016-08-01

    Analytical expressions are derived for aerodynamic drag force on small cylinders in the free molecule flow using the gas-kinetic theory. The derivation considers the effect of intermolecular interactions between the cylinder and gas media. Two limiting collision models, specular and diffuse scattering, are investigated in two limiting cylinder orientations with respect to the drift velocity. The earlier solution of Dahneke [B. E. Dahneke, J. Aerosol Sci. 4, 147 (1973), 10.1016/0021-8502(73)90066-9] is shown to be a special case of the current expressions in the rigid-body limit of collision. Drag force expressions are obtained for cylinders that undergo Brownian rotation and for those that align with the drift velocity. The validity of the theoretical expressions is tested against experimental mobility data available for carbon nanotubes.

  18. 30 CFR 75.1106-6 - Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... containing nonflammable or nonexplosive gas mixtures. 75.1106-6 Section 75.1106-6 Mineral Resources MINE... containing nonflammable or nonexplosive gas mixtures. Small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures, which provide for the emission of such gas under a pressure...

  19. 30 CFR 75.1106-6 - Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... containing nonflammable or nonexplosive gas mixtures. 75.1106-6 Section 75.1106-6 Mineral Resources MINE... containing nonflammable or nonexplosive gas mixtures. Small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures, which provide for the emission of such gas under a pressure...

  20. 30 CFR 75.1106-6 - Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... containing nonflammable or nonexplosive gas mixtures. 75.1106-6 Section 75.1106-6 Mineral Resources MINE... containing nonflammable or nonexplosive gas mixtures. Small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures, which provide for the emission of such gas under a pressure...

  1. 30 CFR 75.1106-6 - Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... containing nonflammable or nonexplosive gas mixtures. 75.1106-6 Section 75.1106-6 Mineral Resources MINE... containing nonflammable or nonexplosive gas mixtures. Small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures, which provide for the emission of such gas under a pressure...

  2. 30 CFR 75.1106-6 - Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... containing nonflammable or nonexplosive gas mixtures. 75.1106-6 Section 75.1106-6 Mineral Resources MINE... containing nonflammable or nonexplosive gas mixtures. Small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures, which provide for the emission of such gas under a pressure...

  3. Characterization of the turbulent bistable flow regime of a 2 D bluff body wake disturbed by a small control cylinder

    NASA Astrophysics Data System (ADS)

    Parezanović, Vladimir; Monchaux, Romain; Cadot, Olivier

    2015-01-01

    A small control cylinder placed in a turbulent wake of a much larger 2 D bluff body can cause a significant increase in drag fluctuations. These fluctuations occur on timescales longer than the timescales of the vortex shedding. The critical positions of the control cylinder are highly localized. Ensemble averages of PIV acquisitions and pressure measurements at the base of the bluff body reveal a bistable wake regime. Long duration hot-wire measurements are used to characterize the states and the transition process. The results show that a stochastic process is responsible for the transitions between the two stable states.

  4. Electrically Controlled Valve With Small Motor

    NASA Technical Reports Server (NTRS)

    Reinicke, Robert H.; Mohtar, Rafic; Nelson, Richard O.

    1992-01-01

    Design of electrically controlled valve exploits force-multiplying principle to overcome large back-pressure force resisting initial opening. Design makes possible to open valve by use of relatively small motor adequate for rest of valve motion, but otherwise not large enough to open valve. In simple linear lifting, small horizontal forces applied to pair of taut cables to lift large weight through short distance. In rotary lifting, similar effect achieved by rotating, about an axis, disk to which initially axial cables attached.

  5. Characterization of Single-Cylinder Small-Bore 4-Stroke CIDI Engine Combustion

    SciTech Connect

    Henein, N A

    2005-11-30

    Direct injection diesel engines power most of the heavy-duty vehicles. Due to their superior fuel economy, high power density and low carbon dioxide emissions, turbocharged, small bore, high speed, direct injection diesel engines are being considered to power light duty vehicles. Such vehicles have to meet stringent emission standards. However, it is difficult to meet these standards by modifying the in-cylinder thermodynamic and combustion processes to reduce engine-out emissions. After-treatment devices will be needed to achieve even lower emission targets required in the production engines to account for the anticipated deterioration after long periods of operation in the field. To reduce the size, mass and cost of the after-treatment devices, there is a need to reduce engine-out emissions and optimize both the engine and the aftertreatment devices as one integrated system. For example, the trade-off between engine-out NOx and PM, suggests that one of these species can be minimized in the engine, with a penalty in the other, which can be addressed efficiently in the after-treatment devices. Controlling engine-out emissions can be achieved by optimizing many engine design and operating parameters. The design parameters include, but are not limited to, the type of injection system: (CRS) Common Rail System, (HEUI ) Hydraulically Actuated and Electronically controlled Unit Injector, or (EUI) Electronic Unit Injector; engine compression ratio, combustion chamber design (bowl design), reentrance geometry, squish area and intake and exhaust ports design. With four-valve engines, the swirl ratio depends on the design of both the tangential and helical ports and their relative locations. For any specific engine design, the operating variables need also to be optimized. These include injection pressure, injection rate, injection duration and timing (pilot, main, and post injection), EGR ratio, and swirl ratio. The goal of the program is to gain a better understanding of

  6. Hypersonic Flow over a Cylinder with a Nanosecond-Pulse Electrical Discharge

    DTIC Science & Technology

    2013-01-01

    ns- DBD ) in a Mach 5 flow demonstrated the feasibility of a plasma-based supersonic flow controller. In the experiment, a bow-shock perturbation on a... DBD , which propagated upstream from the cylinder surface and interacted with the standing bow-shock. This interaction temporarily increased the shock...standoff distance, with the series of events repeated at an interval of 10 μs (100 kHz). Previous demonstrations using the ns- DBD have included

  7. Hypersonic Flow over a Cylinder with a Nanosecond Pulse Electrical Discharge

    DTIC Science & Technology

    2014-03-01

    nanosecond pulsedielectric barrier discharge (ns- DBD ) in a Mach 5 flow demonstrated the feasibility of a plasma-based supersonic flow controller. In the...generated, due to rapid localized heating from the DBD , which propagated upstream from the cylinder surface and interacted with the standing bow shock. This...demonstrations using the ns- DBD have included separated flow reattachment in airflows [3] up to Mach 0.85, characterization of compression wave propagation in

  8. ICPP: Transient Electrical Discharges in Small Devices

    NASA Astrophysics Data System (ADS)

    Soto, Leopoldo

    2000-10-01

    Small devices of low energy and high power are used to study the basic physics and applications of transient electrical discharges. Three experiments are discussed: a) ionization processes and early stage of a Z-pinch under various initial conditions driven by a small generator (10^12 A/s current derivative) (1, 2) , b) high brightness VUV to soft X-ray emission from a fast capillary discharge (5ns rise time, 5kA peak current and 10^12 A/s current derivative) (3), c) neutron pulses (10^4 -10^5 neutrons per pulse) from a small plasma focus (160 nF capacitor bank, 100 - 200 J energy storage) (4). The last device is oriented to repetitive neutron pulses for substance detection. Numerical simulations of the MHD equations have been carried out to assist the experimental design and diagnostics. The diagnostics developed include current and voltage monitors, multipinhole camera with a multichannel plate (four frames, one frame every 4 ns), in order to obtain the plasma dynamics. Also, 1 ns pulse interferometry was implemented to observe the evolution of the electron density profiles. In addition, VUV spectroscopy was applied to characterize the capillary discharge. Electrical characterization of the plasma focus was established. A comprehensive picture of the plasma dynamics and radiation emission behavior is obtained. This work has been funded by FONDECYT grant 1980187 and a Presidential Chair in Science granted by Chilean government. Part of this work, in collaboration with PLADEMA, Argentina (Bilateral agreement CNEA-CCHEN) and in collaboration with Institute of Spectroscopy, ISAN, Troitsk, Russia. 1.- L. Soto, H. Chuaqui, M. Favre, R. Saavedra. E. Wyndham, M. Skowronek, P. Romeas, R. Aliaga-Rossel, and I. Mitchell, IEEE Trans. Plasma Sci. 26, 1179 (1998) 2.- A. Esaulov, P. Sasorov, L. Soto and M. Zambra, ``MHD Simulation of Gas Embedded Plasma Discharge'', submitted for publication. 3.- P. Choi and M. Favre, Rev. Sci. Instrum. 69, 3118, (1998) 4.- C. Moreno, H

  9. Small-scale deflagration cylinder test with velocimetry wall-motion diagnostics

    SciTech Connect

    Hooks, Daniel E; Hill, Larry G; Pierce, Timothy H

    2010-01-01

    Predicting the likelihood and effects of outcomes resultant from thermal initiation of explosives remains a significant challenge. For certain explosive formulations, the general outcome can be broadly predicted given knowledge of certain conditions. However, there remain unexplained violent events, and increased statistical understanding of outcomes as a function of many variables, or 'violence categorization,' is needed. Additionally, the development of an equation of state equivalent for deflagration would be very useful in predicting possible detailed event consequences using traditional hydrodynamic detonation moders. For violence categorization, it is desirable that testing be efficient, such that it is possible to statistically define outcomes reliant on the processes of initiation of deflagration, steady state deflagration, and deflagration to detonation transitions. If the test simultaneously acquires information to inform models of violent deflagration events, overall predictive capabilities for event likelihood and consequence might improve remarkably. In this paper we describe an economical scaled deflagration cylinder test. The cyclotetramethylene tetranitramine (HMX) based explosive formu1lation PBX 9501 was tested using different temperature profiles in a thick-walled copper cylindrical confiner. This test is a scaled version of a recently demonstrated deflagration cylinder test, and is similar to several other thermal explosion tests. The primary difference is the passive velocimetry diagnostic, which enables measurement of confinement vessel wall velocities at failure, regardless of the timing and location of ignition.

  10. Bursting process of large- and small-scale structures in turbulent boundary layer perturbed by a cylinder roughness element

    NASA Astrophysics Data System (ADS)

    Tang, Zhanqi; Jiang, Nan; Zheng, Xiaobo; Wu, Yanhua

    2016-05-01

    Hot-wire measurements on a turbulent boundary layer flow perturbed by a wall-mounted cylinder roughness element (CRE) are carried out in this study. The cylindrical element protrudes into the logarithmic layer, which is similar to those employed in turbulent boundary layers by Ryan et al. (AIAA J 49:2210-2220, 2011. doi: 10.2514/1.j051012) and Zheng and Longmire (J Fluid Mech 748:368-398, 2014. doi: 10.1017/jfm.2014.185) and in turbulent channel flow by Pathikonda and Christensen (AIAA J 53:1-10, 2014. doi: 10.2514/1.j053407). The similar effects on both the mean velocity and Reynolds stress are observed downstream of the CRE perturbation. The series of hot-wire data are decomposed into large- and small-scale fluctuations, and the characteristics of large- and small-scale bursting process are observed, by comparing the bursting duration, period and frequency between CRE-perturbed case and unperturbed case. It is indicated that the CRE perturbation performs the significant impact on the large- and small-scale structures, but within the different impact scenario. Moreover, the large-scale bursting process imposes a modulation on the bursting events of small-scale fluctuations and the overall trend of modulation is not essentially sensitive to the present CRE perturbation, even the modulation extent is modified. The conditionally averaging fluctuations are also plotted, which further confirms the robustness of the bursting modulation in the present experiments.

  11. Feasibility of observing small differences in friction mean effective pressure between different lubricating oil formations using small, single-cylinder motored engine rig

    DOE PAGES

    Rohr, William F.; Nguyen, Ke; Bunting, Bruce G.; ...

    2015-09-01

    Here, the feasibility of using a motored single-cylinder 517 cc diesel engine to observe small frictional differences between oil formulations is investigated. Friction mean effective pressure (FMEP) is measured and compared for an SAE 10W-30 and an SAE 5W-20 oil in three stages of production: base oil, commercial oil without a friction and wear reducing additive, and fully formulated commercial oil. In addition, a commercial SAE 5W-30 engine oil is investigated. Friction mean effective pressure is plotted versus oil dynamic viscosity to compare the lubricant FMEP at a given viscosity. Linear regressions and average friction mean effective pressure are usedmore » as a secondary means of comparing FMEP for the various oil formulations. Differences between the oils are observed with the base oil having higher friction at a given viscosity but a lower average FMEP due to the temperature distribution of the test and lower viscosities reached by the base oil. The commercial oil is shown to have both a higher FMEP at a given viscosity and a higher average FMEP than the commercial oil without a friction and wear reducing additive. The increase in friction for the oil without a friction and wear reduction additive indicates that the operational regime of the engine may be out of the bounds of the optimal regime for the additive or that the additive is more optimized for wear reduction. Results show that it is feasible to observe small differences in FMEP between lubricating oil formulations using a small, single-cylinder motored engine.« less

  12. Feasibility of observing small differences in friction mean effective pressure between different lubricating oil formations using small, single-cylinder motored engine rig

    SciTech Connect

    Rohr, William F.; Nguyen, Ke; Bunting, Bruce G.; Qu, Jun

    2015-09-01

    Here, the feasibility of using a motored single-cylinder 517 cc diesel engine to observe small frictional differences between oil formulations is investigated. Friction mean effective pressure (FMEP) is measured and compared for an SAE 10W-30 and an SAE 5W-20 oil in three stages of production: base oil, commercial oil without a friction and wear reducing additive, and fully formulated commercial oil. In addition, a commercial SAE 5W-30 engine oil is investigated. Friction mean effective pressure is plotted versus oil dynamic viscosity to compare the lubricant FMEP at a given viscosity. Linear regressions and average friction mean effective pressure are used as a secondary means of comparing FMEP for the various oil formulations. Differences between the oils are observed with the base oil having higher friction at a given viscosity but a lower average FMEP due to the temperature distribution of the test and lower viscosities reached by the base oil. The commercial oil is shown to have both a higher FMEP at a given viscosity and a higher average FMEP than the commercial oil without a friction and wear reducing additive. The increase in friction for the oil without a friction and wear reduction additive indicates that the operational regime of the engine may be out of the bounds of the optimal regime for the additive or that the additive is more optimized for wear reduction. Results show that it is feasible to observe small differences in FMEP between lubricating oil formulations using a small, single-cylinder motored engine.

  13. 76 FR 647 - Energy Conservation Program: Test Procedures for Electric Motors and Small Electric Motors

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-05

    ...This supplemental notice of proposed rulemaking (SNOPR) proposes to clarify certain terms and language in our regulations for certain commercial and industrial equipment, as follows: revise the definitions of certain terms related to electric motors and small electric motors, clarify the scope of energy conservation standards for electric motors, update references to several industry and......

  14. Electrochemical reclamation of silver from silver-plating wastewater using static cylinder electrodes and a pulsed electric field.

    PubMed

    Su, Yuan-Bo; Li, Qing-Biao; Wang, Yuan-Peng; Wang, Hai-Tao; Huang, Jia-le; Yang, Xin

    2009-10-30

    Silver was reclaimed from silver-plating wastewater by using a pulsed electric field (PEF) combined with static cylinder electrodes (SCE). The conditions that produced the maximal silver recovery rate (RR(Ag)) (99%) were as follows: average retention time of 10 min, interelectrode gap of 50mm, solution pH of 9.0, temperature of 45 degrees C, initial Ag(I) concentration of 1000 mg L(-1), PEF pulse frequency of 1200 Hz, current density of 5.0 A m(-2) and a pulse duty cycle of 60%. Compared with the conventional direct current (DC) technology, the PEF process exhibited improvements in the silver recovery rate (RR(Ag)), total energy consumption (TEC) and physical properties of the silver deposits, especially for low Ag(I) concentrations, for example, from 500 to 1000 mg L(-1). For an initial Ag(I) concentration of 500 mg L(-1), the PEF process produced an RR(Ag) of up to 99%, and the TEC was 4.56 kWh (kg Ag)(-1). In comparison, the RR(Ag) and TEC were 90% and 5.66 kWh (kg Ag)(-1), respectively, in the DC process. The results of SEM observation and XRD analysis indicated that the silver deposits formed by the PEF process were smaller, denser, and of a higher purity than those produced by the DC process. Therefore, the presented method was effective for reclaiming silver from silver-plating wastewater.

  15. Small geothermal electric systems for remote powering

    SciTech Connect

    Entingh, Daniel J.; Easwaran, Eyob.; McLarty, Lynn

    1994-08-08

    This report describes conditions and costs at which quite small (100 to 1,000 kilowatt) geothermal systems could be used for off-grid powering at remote locations. This is a first step in a larger process of determining locations and conditions at which markets for such systems could be developed. The results suggest that small geothermal systems offer substantial economic and environmental advantages for powering off-grid towns and villages. Geothermal power is most likely to be economic if the system size is 300 kW or greater, down to reservoir temperatures of 100{degree}C. For system sizes smaller than 300 kW, the economics can be favorable if the reservoir temperature is about 120{degree}C or above. Important markets include sites remote from grids in many developing and developed countries. Estimates of geothermal resources in many developing countries are shown.

  16. Biomagnetic Techniques for Assessing Gastric and Small Bowel Electrical Activity

    NASA Astrophysics Data System (ADS)

    Bradshaw, L. Alan

    2004-09-01

    Recent advances in electrophysiology of the gastrointestinal tract have emphasized the need for methods of noninvasive assessment of gastric and small intestinal electrical activity (GEA and IEA). While the cutaneous electrogastrogram (EGG) may reveal the frequency dynamics of gastric electrical activity, other parameters important for characterizing the propagating electrical activity are not available from EGG recordings. Recent studies on the electroenterogram (EENG) are promising, but low-conductivity abdominal layers have complicated the identification of small intestinal electrical rhythms in cutaneous recordings. The magnetogastrogram (MGG) and magnetoenterogram (MENG) are able to characterize gastric and intestinal electrical activity noninvasively in terms of its frequency, power and characteristics of its propagation. Superconducting QUantum Interference Device (SQUID) magnetometers are used to detect the minute magnetic fields associated with electrical activity of the gastrointestinal syncytium formed by interstitial cells of Cajal and smooth muscle networks. Changes in GEA and IEA that occur in response to disease or abnormal conditions are reflected in MGG and MENG signals. Magnetic methods for assessing the electrical activity of the stomach and small bowel thus show great clinical promise.

  17. A new probe for measuring small electric fields in plasmas

    NASA Technical Reports Server (NTRS)

    Stenzel, R. L.

    1991-01-01

    A dipolar double probe has been developed for in situ measurements of small electric fields in laboratory plasmas. The probe measures dc to ac electric fields (f values between 0 and 20 MHz) with high sensitivity (Emin about 10 microV/cm) and responds to both space charge electric fields and inductive electric fields. Using voltage-to-frequency conversion, the probe signal is obtained free of errors and loading effects by a transmission line. Various examples of useful applications for the new probe are presented, such as measurements of dc ambipolar fields, ac space-charge fields of ion acoustic waves, ac inductive fields of whistler waves, and mixed inductive and space-charge electric fields in current-carrying magnetoplasmas.

  18. Determination of the 235U Mass and Enrichment within Small UF6 Cylinders via a Neutron Coincidence Well Counting System

    SciTech Connect

    McElroy, Robert Dennis; Croft, Dr. Stephen; Young, Brian M; Venkataraman, Ram

    2011-01-01

    The construction of three new uranium enrichment facilities in the United States has sparked renewed interest in the development and enhancement of methods to determine the enrichment and fissile mass content of UF6 cylinders. We describe the design and examine the expected performance of a UF6 bottle counter developed for the assay of Type 5A cylinders. The counter, as designed and subsequently constructed, is a tall passive neutron well counter with a clam-shell configuration and graphite end plugs operated in fast neutron mode. Factory performance against expectation is described. The relatively high detection efficiency and effectively 4 detection geometry provide a near-ideal measurement configuration, making the UF6 bottle counter a valuable tool for the evaluation of the neutron coincidence approach to UF6 cylinder assay. The impacts of non-uniform filling, voids, enrichment, and mixed enrichments are examined

  19. A tunable spherical cap microfluidic electrically small antenna.

    PubMed

    Jobs, Magnus; Hjort, Klas; Rydberg, Anders; Wu, Zhigang

    2013-10-11

    A highly efficient microfluidic 3D electrically small antenna is created using a simple fabrication technique. It is easy to construct simply by pneumatically inflating a planar microfluidic antenna into a spherical cap. It has premium performance around its hemispherical shape, combining a wide working band with high efficiency.

  20. Small Wind Electric Systems: A Nebraska Consumer's Guide

    SciTech Connect

    2009-01-18

    This guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and economics.

  1. Small Wind Electric Systems: A Rhode Island Consumer's Guide

    SciTech Connect

    2003-06-01

    This guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and economics.

  2. Small Wind Electric Systems: A New Mexico Consumer's Guide

    SciTech Connect

    2004-08-01

    This guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and economics.

  3. Small Wind Electric Systems: An Indiana Consumer's Guide

    SciTech Connect

    2009-01-18

    This guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and economics.

  4. Small Wind Electric Systems: A Utah Consumer's Guide

    SciTech Connect

    2009-01-18

    This guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and economics.

  5. Small Wind Electric Systems: A Hawaii Consumer's Guide

    SciTech Connect

    2009-01-18

    This guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and economics.

  6. Small Wind Electric Systems: A Missouri Consumer's Guide

    SciTech Connect

    2009-01-18

    This guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and economics.

  7. Small Wind Electric Systems: A Vermont Consumer's Guide

    SciTech Connect

    2004-10-01

    This guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and economics.

  8. Small Wind Electric Systems: An Oklahoma Consumer's Guide

    SciTech Connect

    2009-01-18

    This guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and economics.

  9. Small Wind Electric Systems: A Nevada Consumer's Guide

    SciTech Connect

    2009-01-18

    This guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and economics.

  10. Small Wind Electric Systems: A Michigan Consumer's Guide

    SciTech Connect

    2009-01-18

    This guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and economics.

  11. Calculation of the electric potential and the Lorentz force in a transverse flow past a circular cylinder in a nonuniform magnetic field for various configurations of a locally ionized region at the cylinder surface

    NASA Astrophysics Data System (ADS)

    Sheikin, E. G.; Cheng, Wei Yang

    2013-12-01

    We obtain a solution to the equation for the electric potential in a locally ionized transverse magnetohydrodynamic flow past a circular cylinder in a nonuniform magnetic field produced by a linear conductor for various configurations of the ionization region. Analytical formulas are derived for the volume density of the Lorentz force acting on the flow in a locally ionized region. The effect of the Hall parameter and of the configuration of the region of the magnetohydrodynamic interaction on the Lorentz force is analyzed. It is shown that an increase in the Hall parameter leads to a decrease in the Lorentz force acting on the flow, and a change in the configuration of the locally ionized region makes it possible to suppress the effect of the Hall parameter on the Lorentz force.

  12. Small Wind Electric Systems: A Michigan Consumer's Guide (revised)

    SciTech Connect

    Not Available

    2007-01-01

    Small Wind Electric Systems: A Michigan Consumer's Guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and economics. Topics include how to make a home more energy efficient, how to choose the correct turbine size, the parts of a wind electric system, how to determine whether enough wind resource exists, how to choose the best site for a turbine, how to connect a system to the utility grid, and whether it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a list of contacts for more information.

  13. Small Wind Electric Systems: An Oklahoma Consumer's Guide

    SciTech Connect

    Not Available

    2007-08-01

    Small Wind Electric Systems: An Oklahoma Consumer's Guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and economics. Topics include how to make a home more energy efficient, how to choose the correct turbine size, the parts of a wind electric system, how to determine whether enough wind resource exists, how to choose the best site for a turbine, how to connect a system to the utility grid, and whether it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a list of contacts for more information.

  14. Small Wind Electric Systems: A Kansas Consumer's Guide

    SciTech Connect

    Not Available

    2007-08-01

    Small Wind Electric Systems: A Kansas Consumer's Guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and their economics. Topics discussed in the guide include how to make a home more energy efficient, how to choose the correct turbine size, the parts of a wind electric system, how to determine whether enough wind resource exists, how to choose the best site for a turbine, how to connect a system to the utility grid, and whether it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a list of contacts for more information.

  15. Small Wind Electric Systems: A Pennsylvania Consumer's Guide

    SciTech Connect

    Not Available

    2007-08-01

    Small Wind Electric Systems: A Pennsylvania Consumer's Guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and their economics. Topics discussed in the guide include how to make a home more energy efficient, how to choose the correct turbine size, the parts of a wind electric system, how to determine whether enough wind resource exists, how to choose the best site for a turbine, how to connect a system to the utility grid, and whether it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a list of contacts for more information.

  16. Small Wind Electric Systems: A Maryland Consumer's Guide

    SciTech Connect

    Not Available

    2007-01-01

    Small Wind Electric Systems: A Maryland Consumer's Guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and economics. Topics include how to make a home more energy efficient, how to choose the correct turbine size, the parts of a wind electric system, how to determine whether enough wind resource exists, how to choose the best site for a turbine, how to connect a system to the utility grid, and whether it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a list of contacts for more information.

  17. Small Wind Electric Systems: An Alaska Consumer's Guide

    SciTech Connect

    Not Available

    2007-04-01

    Small Wind Electric Systems: An Alaska Consumer's Guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and economics. Topics include how to make a home more energy efficient, how to choose the correct turbine size, the parts of a wind electric system, how to determine whether enough wind resource exists, how to choose the best site for a turbine, how to connect a system to the utility grid, and whether it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a list of contacts for more information.

  18. Small Wind Electric Systems: A Utah Consumer's Guide

    SciTech Connect

    Not Available

    2007-08-01

    Small Wind Electric Systems: A Utah Consumer's Guide provides Utah consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and their economics. Topics discussed in the guide include how to make a home more energy efficient, how to choose the correct turbine size, the parts of a wind electric system, how to determine whether enough wind resource exists, how to choose the best site for a turbine, how to connect a system to the utility grid, and whether it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a list of contacts for more information.

  19. Small Wind Electric Systems: A Maine Consumer's Guide

    SciTech Connect

    Not Available

    2007-08-01

    Small Wind Electric Systems: A Maine Consumer's Guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and their economics. Topics discussed in the guide include how to make a home more energy efficient, how to choose the correct turbine size, the parts of a wind electric system, how to determine whether enough wind resource exists, how to choose the best site for a turbine, how to connect a system to the utility grid, and whether it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a list of contacts for more information.

  20. Small Wind Electric Systems: A U.S. Consumer's Guide

    SciTech Connect

    Not Available

    2007-08-01

    Small Wind Electric Systems: A U.S. Consumer's Guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and their economics. Topics discussed in the guide include how to make a home more energy efficient, how to choose the correct turbine size, the parts of a wind electric system, how to determine whether enough wind resource exists, how to choose the best site for a turbine, how to connect a system to the utility grid, and whether it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a list of contacts for more information.

  1. Small Wind Electric Systems: A Maryland Consumer's Guide (Revised)

    SciTech Connect

    Not Available

    2009-08-01

    Small Wind Electric Systems: A Maryland Consumer's Guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and their economics. Topics discussed in the guide include how to make a home more energy efficient, how to choose the correct turbine size, the parts of a wind electric system, how to determine whether enough wind resource exists, how to choose the best site for a turbine, how to connect a system to the utility grid, and whether it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a regional wind resource map and a list of incentives and contacts for more information.

  2. Small Wind Electric Systems: An Oregon Consumer's Guide

    SciTech Connect

    Not Available

    2007-08-01

    Small Wind Electric Systems: An Oregon Consumer's Guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and economics. Topics include how to make a home more energy efficient, how to choose the correct turbine size, the parts of a wind electric system, how to determine whether enough wind resource exists, how to choose the best site for a turbine, how to connect a system to the utility grid, and whether it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a list of contacts for more information.

  3. Small Wind Electric Systems: A Montana Consumer's Guide (Revised)

    SciTech Connect

    Not Available

    2006-04-01

    Small Wind Electric Systems: A Montana Consumer's Guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and economics. Topics include how to make a home more energy efficient, how to choose the correct turbine size, the parts of a wind electric system, how to determine whether enough wind resource exists, how to choose the best site for a turbine, how to connect a system to the utility grid, and whether it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a list of contacts for more information.

  4. Small Wind Electric Systems: A Montana Consumer's Guide

    SciTech Connect

    Not Available

    2007-08-01

    Small Wind Electric Systems: A Montana Consumer's Guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and economics. Topics include how to make a home more energy efficient, how to choose the correct turbine size, the parts of a wind electric system, how to determine whether enough wind resource exists, how to choose the best site for a turbine, how to connect a system to the utility grid, and whether it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a list of contacts for more information.

  5. Small Wind Electric Systems: A North Dakota Consumer's Guide

    SciTech Connect

    Not Available

    2007-04-01

    Small Wind Electric Systems: A North Dakota Consumer's Guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and economics. Topics include how to make a home more energy efficient, how to choose the correct turbine size, the parts of a wind electric system, how to determine whether enough wind resource exists, how to choose the best site for a turbine, how to connect a system to the utility grid, and whether it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a list of contacts for more information.

  6. Small Wind Electric Systems: A Washington Consumer's Guide

    SciTech Connect

    Not Available

    2007-08-01

    Small Wind Electric Systems: A Washington Consumer's Guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and economics. Topics include how to make a home more energy efficient, how to choose the correct turbine size, the parts of a wind electric system, how to determine whether enough wind resource exists, how to choose the best site for a turbine, how to connect a system to the utility grid, and whether it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a list of contacts for more information.

  7. Small Wind Electric Systems: A Minnesota Consumer's Guide

    SciTech Connect

    Not Available

    2007-04-01

    Small Wind Electric Systems: A Minnesota Consumer's Guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and economics. Topics include how to make a home more energy efficient, how to choose the correct turbine size, the parts of a wind electric system, how to determine whether enough wind resource exists, how to choose the best site for a turbine, how to connect a system to the utility grid, and whether it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a list of contacts for more information.

  8. Small Wind Electric Systems: An Illinois Consumer's Guide

    SciTech Connect

    Not Available

    2007-04-01

    Small Wind Electric Systems: An Illinois Consumer's Guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and economics. Topics include how to make a home more energy efficient, how to choose the correct turbine size, the parts of a wind electric system, how to determine whether enough wind resource exists, how to choose the best site for a turbine, how to connect a system to the utility grid, and whether it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a list of contacts for more information.

  9. Small Wind Electric Systems: A Colorado Consumer's Guide

    SciTech Connect

    Not Available

    2006-12-01

    Small Wind Electric Systems: A Colorado Consumer's Guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and economics. Topics include how to make a home more energy efficient, how to choose the correct turbine size, the parts of a wind electric system, how to determine whether enough wind resource exists, how to choose the best site for a turbine, how to connect a system to the utility grid, and whether it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a list of contacts for more information.

  10. Small Wind Electric Systems: A Hawaii Consumer's Guide

    SciTech Connect

    Not Available

    2007-08-01

    Small Wind Electric Systems: A Hawaii Consumer's Guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and their economics. Topics discussed in the guide include how to make a home more energy efficient, how to choose the correct turbine size, the parts of a wind electric system, how to determine whether enough wind resource exists, how to choose the best site for a turbine, how to connect a system to the utility grid, and whether it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a list of contacts for more information.

  11. Small Wind Electric Systems: An Ohio Consumer's Guide

    SciTech Connect

    Not Available

    2007-08-01

    Small Wind Electric Systems: An Ohio Consumer's Guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and their economics. Topics discussed in the guide include how to make a home more energy efficient, how to choose the correct turbine size, the parts of a wind electric system, how to determine whether enough wind resource exists, how to choose the best site for a turbine, how to connect a system to the utility grid, and whether it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a list of contacts for more information.

  12. Small Wind Electric Systems: A South Dakota Consumer's Guide

    SciTech Connect

    Not Available

    2007-04-01

    Small Wind Electric Systems: A South Dakota Consumer's Guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and economics. Topics include how to make a home more energy efficient, how to choose the correct turbine size, the parts of a wind electric system, how to determine whether enough wind resource exists, how to choose the best site for a turbine, how to connect a system to the utility grid, and whether it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a list of contacts for more information.

  13. Small Wind Electric Systems: A Vermont Consumer's Guide

    SciTech Connect

    Not Available

    2007-04-01

    Small Wind Electric Systems: A Vermont Consumer's Guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and economics. Topics include how to make a home more energy efficient, how to choose the correct turbine size, the parts of a wind electric system, how to determine whether enough wind resource exists, how to choose the best site for a turbine, how to connect a system to the utility grid, and whether it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a list of contacts for more information.

  14. Small Wind Electric Systems: A Nebraska Consumer's Guide

    SciTech Connect

    Not Available

    2007-12-01

    Small Wind Electric Systems: A Nebraska Consumer's Guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and their economics. Topics discussed in the guide include how to make a home more energy efficient, how to choose the correct turbine size, the parts of a wind electric system, how to determine whether enough wind resource exists, how to choose the best site for a turbine, how to connect a system to the utility grid, and whether it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a list of contacts for more information.

  15. Small Wind Electric Systems: An Oregon Consumer's Guide

    SciTech Connect

    Not Available

    2002-05-01

    Small Wind Electric Systems An Oregon Consumer's Guide provides consumers with enough information to help them determine if a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and their economics. Topics discussed in the guide include: how to make your home more energy efficient, how to choose the right size turbine, the parts of a wind electric system, determining if there is enough wind resource on your site, choosing the best site for your turbine, connecting your system to the utility grid, and if it's possible to become independent of the utility grid using wind energy. In addition, the Oregon guide provides state specific information that includes and state wind resource map, state incentives, and state contacts for more information.

  16. Small Wind Electric Systems: An Oregon Consumer's Guide

    SciTech Connect

    Not Available

    2005-03-01

    Small Wind Electric Systems: An Oregon Consumer's Guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and their economics. Topics discussed in the guide include how to make a home more energy efficient, how to choose the correct turbine size, the parts of a wind electric system, how to determine whether enough wind resource exists, how to choose the best site for a turbine, how to connect a system to the utility grid, and whether it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a regional wind resource map and a list of incentives and contacts for more information.

  17. Small Wind Electric Systems: A U.S. Consumer's Guide

    SciTech Connect

    Not Available

    2004-05-01

    Small Wind Electric Systems: A U.S. Consumer's Guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and their economics. Topics discussed in the guide include how to make a home more energy efficient, how to choose the correct turbine size, the parts of a wind electric system, how to determine whether enough wind resource exists, how to choose the best site for a turbine, how to connect a system to the utility grid, and whether it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a regional wind resource map and a list of incentives and contacts for more information.

  18. Small Wind Electric Systems: A Virginia Consumer's Guide

    SciTech Connect

    Not Available

    2007-01-01

    Small Wind Electric Systems: A Virginia Consumer's Guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and economics. Topics include how to make a home more energy efficient, how to choose the correct turbine size, the parts of a wind electric system, how to determine whether enough wind resource exists, how to choose the best site for a turbine, how to connect a system to the utility grid, and whether it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a list of contacts for more information.

  19. The Effect of Small Bubbles on Resistance Reduction of Water Flow in Co-axial Cylinders with an Inner Rotating Cylinder

    NASA Astrophysics Data System (ADS)

    Maryami, R.; Farahat, S.; Poor, M. J.

    2015-04-01

    Drawing on effective experiments and measurement technology, the present study seeks to discuss the interaction between liquid turbulent boundary layer and a crowded group of small bubbles. Experiments are carried out using a circulating water Couette-Taylor system especially designed for small bubble experiments. Couette-Taylor system has a detailed test section, which allows measuring the effect of persistent head resistance reduction caused by small bubbles in the streamwise direction. Pressure difference is measured using sensors which are mounted at the bottom and top of the system to calculate head resistance. Pressure difference and bubble behavior are measured as a function of rotational Reynolds number up to 67.8 × 103. Small bubbles are injected constantly into annulus gap using two injectors installed at the bottom of the system and they are lifted through an array of vertical cells. Water is used to avoid uncertain interfacial property of bubbles and to produce relatively mono-sized bubble distributions. The bubble sizes range approximately from 0.9 to 1.4 mm, which are identified by the image processing method. The results suggest that head resistance is decreased after the injection of small bubble in all rotational Reynolds number under study, changing from 7,000 to 67.8 × 103. Moreover, void fraction is increased from 0 to 10.33 %. A head resistance reduction greater than 75 % was achieved in this study after the maximum measured volume of air fraction was injected into fluid flow while bubbles were distinct without making any gas layer.

  20. Normal and abnormal electrical propagation in the small intestine.

    PubMed

    Lammers, W J E P

    2015-02-01

    As in other muscular organs, small intestinal motility is determined to a large degree by the electrical activities that occur in the smooth muscle layers of the small intestine. In recent decades, the interstitial cells of Cajal, located in the myenteric plexus, have been shown to be responsible for the generation and propagation of the electrical impulse: the slow wave. It was also known that the slow waves as such do not cause contraction, but that the action potentials ('spikes') that are generated by the slow waves are responsible for the contractions. Recording from large number of extracellular electrodes simultaneously is one method to determine origin and pattern of propagation of these electrical signals. This review reports the characteristics of slow wave propagation through the intestinal tube, the occurrence of propagation blocks along its length, which explains the well-known decrease in frequency, and the specific propagation pattern of the spikes that follow the slow waves. But the value of high-resolution mapping is highest in discovering and analysing mechanisms of arrhythmias in the gut. Most recently, circus movements (also called 're-entries') have been described in the small intestine in several species. Moreover, several types of re-entries have now been described, some similar to what may occur in the heart, such as functional re-entries, but others more unique to the small intestine, such as circumferential re-entry. These findings seem to suggest the possibilities of hitherto unknown pathologies that may be present in the small intestine.

  1. Small Wind Electric Systems: A U.S. Consumer's Guide

    SciTech Connect

    2007-08-01

    The handbook provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and their economics. Topics discussed in the guide include how to make a home more energy efficient, how to choose the correct turbine size, the parts of a wind electric system, how to determine whether enough wind resource exists, how to choose the best site for a turbine, how to connect a system to the utility grid, and whether it's possible to become independent of the utility grid using wind energy.

  2. Small solar thermal electric power plants with early commercial potential

    NASA Technical Reports Server (NTRS)

    Jones, H. E.; Bisantz, D. J.; Clayton, R. N.; Heiges, H. H.; Ku, A. C.

    1979-01-01

    Cost-effective small solar thermal electric power plants (1- to 10-MW nominal size) offer an attractive way of helping the world meet its future energy needs. The paper describes the characteristics of a conceptual near-term plant (about 1 MW) and a potential 1990 commercial version. The basic system concept is one in which steam is generated using two-axis tracking, parabolic dish, and point-focusing collectors. The steam is transported through low-loss piping to a central steam turbine generator unit where it is converted to electricity. The plants have no energy storage and their output power level varies with the solar insolation level. This system concept, which is firmly based on state-of-the-art technology, is projected to offer one of the fastest paths for U.S. commercialization of solar thermal electric power plants through moderate technology advances and mass production.

  3. Discernible trend in electric rates for small businesses

    SciTech Connect

    Hickel, J.K.

    1984-06-07

    Over the past several years, small businesses as a customer class for utilities have been paying more for electricity on a kilowatt-hour basis than any other class, a situation that did not hold prior to the mid-1970s. This article examines various reasons that have been advanced to explain this trend, evaluating their comparative validity. These include assertions that small business users place a greater peak demand on the utility system than other customers, or may otherwise cost more to serve; that standards mandated by the Public Utility Regulatory Policies Act and National Energy Policy Conservation Act may affect small businesses disproportionately; and that the minimal or nonexistent participation of small business in utility rate hearings encourages regulatory commissions and utilities to allocate a disproportionate share of costs to this class. 20 references, 2 figures, 2 tables.

  4. Electrically small resonators for energy harvesting in the infrared regime

    NASA Astrophysics Data System (ADS)

    AlShareef, Mohammed R.; Ramahi, Omar M.

    2013-12-01

    A novel structure based on electrically small resonators is proposed for harvesting the infrared energy and yielding more than 80% harvesting efficiency. The dispersion effect of the dielectric and conductor materials of the resonators is taken into account by applying the Drude model. A new scheme to channel the infrared waves from an array of split ring resonators is proposed, whereby a wide-bandwidth collector is utilized by employing this new channeling concept.

  5. Small intestinal model for electrically propelled capsule endoscopy

    PubMed Central

    2011-01-01

    The aim of this research is to propose a small intestine model for electrically propelled capsule endoscopy. The electrical stimulus can cause contraction of the small intestine and propel the capsule along the lumen. The proposed model considered the drag and friction from the small intestine using a thin walled model and Stokes' drag equation. Further, contraction force from the small intestine was modeled by using regression analysis. From the proposed model, the acceleration and velocity of various exterior shapes of capsule were calculated, and two exterior shapes of capsules were proposed based on the internal volume of the capsules. The proposed capsules were fabricated and animal experiments were conducted. One of the proposed capsules showed an average (SD) velocity in forward direction of 2.91 ± 0.99 mm/s and 2.23 ± 0.78 mm/s in the backward direction, which was 5.2 times faster than that obtained in previous research. The proposed model can predict locomotion of the capsule based on various exterior shapes of the capsule. PMID:22177218

  6. 10 CFR 431.445 - Determination of small electric motor efficiency.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 3 2011-01-01 2011-01-01 false Determination of small electric motor efficiency. 431.445... COMMERCIAL AND INDUSTRIAL EQUIPMENT Small Electric Motors Test Procedures § 431.445 Determination of small electric motor efficiency. (a) Scope. When a party determines the energy efficiency of a small...

  7. Torque vectoring for improving stability of small electric vehicles

    NASA Astrophysics Data System (ADS)

    Grzegożek, W.; Weigel-Milleret, K.

    2016-09-01

    The electric vehicles solutions based on the individually controlled electric motors propel a single wheel allow to improve the dynamic properties of the vehicle by varying the distribution of the driving torque. Most of the literature refer to the vehicles with a track typical for passenger cars. This paper examines whether the narrow vehicle (with a very small track) torque vectoring bring a noticeable change of the understeer characteristics and whether torque vectoring is possible to use in securing a narrow vehicle from roll over (roll mitigation). The paper contains road tests of the steering characteristics (steady state understeer characteristic quasi-static acceleration with a fixed steering wheel (SH = const) and on the constant radius track (R = const)) of the narrow vehicle. The vehicle understeer characteristic as a function of a power distribution is presented.

  8. Efficiency of electrically small antennas combined with matching networks

    NASA Technical Reports Server (NTRS)

    Smith, G. S.

    1977-01-01

    In applications where electrically small antennas are necessary and transmitter power is limited, the system efficiency may be a critical parameter in determining the feasibility of the system. The principle of conservation of energy is used to determine the efficiency of an antenna combined with a matching network composed of elements with finite quality factors. It is shown that conditions for maximum efficiency can be met by using a simple L section as the matching network. Illustrative examples concern a cryogenic loop antenna and a ferrite loaded loop antenna.

  9. Small Power Systems Solar Electric Workshop Proceedings. Volume 1: Executive report. Volume 2: Invited papers

    NASA Technical Reports Server (NTRS)

    Ferber, R. (Editor); Evans, D. (Editor)

    1978-01-01

    The background, objectives and methodology used for the Small Power Systems Solar Electric Workshop are described, and a summary of the results and conclusions developed at the workshop regarding small solar thermal electric power systems is presented.

  10. 10 CFR 431.446 - Small electric motors energy conservation standards and their effective dates.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 3 2013-01-01 2013-01-01 false Small electric motors energy conservation standards and... EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Small Electric Motors Energy Conservation Standards § 431.446 Small electric motors energy conservation standards and their effective dates. (a)...

  11. 10 CFR 431.446 - Small electric motors energy conservation standards and their effective dates.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 3 2012-01-01 2012-01-01 false Small electric motors energy conservation standards and... EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Small Electric Motors Energy Conservation Standards § 431.446 Small electric motors energy conservation standards and their effective dates. (a)...

  12. 10 CFR 431.446 - Small electric motors energy conservation standards and their effective dates.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 3 2014-01-01 2014-01-01 false Small electric motors energy conservation standards and... EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Small Electric Motors Energy Conservation Standards § 431.446 Small electric motors energy conservation standards and their effective dates. (a)...

  13. 10 CFR 431.446 - Small electric motors energy conservation standards and their effective dates. [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 3 2010-01-01 2010-01-01 false Small electric motors energy conservation standards and... EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Small Electric Motors Energy Conservation Standards § 431.446 Small electric motors energy conservation standards and their effective dates....

  14. 10 CFR 431.446 - Small electric motors energy conservation standards and their effective dates.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 3 2011-01-01 2011-01-01 false Small electric motors energy conservation standards and... EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Small Electric Motors Energy Conservation Standards § 431.446 Small electric motors energy conservation standards and their effective dates. (a)...

  15. A modular electric power system test bed for small spacecraft

    NASA Technical Reports Server (NTRS)

    Button, Robert M.; Baez, Anastacio N.

    1994-01-01

    In the new climate of smaller, faster, and cheaper space science satellites, a new power system topology has been developed at the NASA Lewis Research Center. This new topology is based on a series connected boost converter (SCBC) and can greatly affect the size, weight, fault tolerance, and cost of any small spacecraft using photovoltaic solar arrays. The paper presents electric power system design factors and requirements as background information. The series connected boost converter topology is discussed and several advantages over existing technologies are illustrated. Besides being small, lightweight, and efficient, this topology has the added benefit of inherent fault tolerance. A positive ground power system test bed has been developed for the TROPIX spacecraft program. Performance of the SCBC in the test bed is described in detail. SCBC efficiencies of 95 percent to 98 percent have been measured. Finally, a modular, photovoltaic regulator 'kit' concept is presented. Two SCBC's are used to regulate solar array charging of batteries and to provide 'utilitytype' power to the user loads. The kit's modularity will allow a spacecraft electric power system to be built from off-the-shelf hardware; resulting in smaller, faster, and cheaper spacecraft.

  16. A modular electric power system test bed for small spacecraft

    NASA Astrophysics Data System (ADS)

    Button, Robert M.; Baez, Anastacio N.

    1994-12-01

    In the new climate of smaller, faster, and cheaper space science satellites, a new power system topology has been developed at the NASA Lewis Research Center. This new topology is based on a series connected boost converter (SCBC) and can greatly affect the size, weight, fault tolerance, and cost of any small spacecraft using photovoltaic solar arrays. The paper presents electric power system design factors and requirements as background information. The series connected boost converter topology is discussed and several advantages over existing technologies are illustrated. Besides being small, lightweight, and efficient, this topology has the added benefit of inherent fault tolerance. A positive ground power system test bed has been developed for the TROPIX spacecraft program. Performance of the SCBC in the test bed is described in detail. SCBC efficiencies of 95 percent to 98 percent have been measured. Finally, a modular, photovoltaic regulator 'kit' concept is presented. Two SCBC's are used to regulate solar array charging of batteries and to provide 'utilitytype' power to the user loads. The kit's modularity will allow a spacecraft electric power system to be built from off-the-shelf hardware; resulting in smaller, faster, and cheaper spacecraft.

  17. A solar thermal electric power plant for small communities

    NASA Technical Reports Server (NTRS)

    Holl, R. J.

    1979-01-01

    A solar power plant has been designed with a rating of 1000-kW electric and a 0.4 annual capacity factor. It was configured as a prototype for plants in the 1000 to 10,000-kWe size range for application to small communities or industrial users either grid-connected or isolated from a utility grid. A small central receiver was selected for solar energy collection after being compared with alternative distributed collectors. Further trade studies resulted in the selection of Hitec (heat transfer salt composed of 53 percent KNO3, 40 percent NaNO2, 7 percent NaNO3) as both the receiver coolant and the sensible heat thermal stroage medium and the steam Rankine cycle for power conversion. The plant is configured with road-transportable units to accommodate remote sites and minimize site assembly requirements. Results of the analyses indicate that busbar energy costs are competitive with diesel-electric plants in certain situations, e.g., off-grid, remote regions with high insolation. Sensitivity of energy costs to plant power rating and system capacity factor are given.

  18. LiNbO3 Cylinder Fiber

    NASA Technical Reports Server (NTRS)

    Kornreich, Philip

    2004-01-01

    We have successfully fabricate optical fiber with a thin layer of LiNbO3 at the boundary of the glass core and clear glass cladding. The construction of this fiber is based on our successful Semiconductor Cylinder Fibers (SCF). A schematic representation of a LiN bo, Cylinder Fiber. These fibers can be used as light modulators, sonar detectors and in other applications. The core diameter of the fiber is sufficiently small compared to the light wavelength and the indices of refraction of the core and cladding glasses are sufficiently close in value so that there is sufficient light at the core cladding boundary to interact with the LiNbO3 layer. This fiber functions best when just a single light mode propagates through the fiber. The idea for a LiNbO3 Cylinder Fiber came from Dr. Tracee Jamison of NASA. The optical properties of LiNbO3 can be changed with strain or the application of an electric field. Thus these fibers can be used as acoustic sensors as for example in a sonar. They can also be used as electric field operated light modulators. However, for this application the fibers would be made with a cross section in the form of a "D". The core with its surrounding LiNbO, layer would be close to the flat portion of the "D" shaped fiber. Two metal contacts would be deposited on the flat portion of the fiber on either side of the core. A voltage applied across these contacts will result in an electric field in the core region that can be used for modulating the optical properties of the LiNbO3 layer. To our knowledge this is the first ever LiNbO3 Cylinder Fiber made.

  19. LiNbO3 Cylinder Fiber

    NASA Technical Reports Server (NTRS)

    2004-01-01

    We have successfully fabricate optical fiber with a thin layer of LiNbO3 at the boundary of the glass core and dear glass cladding. The construction of this fiber is based on our successful Semiconductor Cylinder Fibers (SCF). A schematic representation of a LiNbO3 Cylinder Fiber is shown. These fibers can be used as light modulators, sonar detectors and in other applications. The core diameter of the fiber is sufficiently small compared to the light wavelength and the indices of refraction of the core and cladding glasses are sufficiently close in value so that there is sufficient light at the core cladding boundary to interact with the LiNbO3 layer. This fiber functions best when just a single light mode propagates through the fiber. The idea for a LiNbO3 Cylinder Fiber came from Dr. Tracee Jamison of NASA. The optical properties of LiNbO3 can be changed with strain or the application of an electric field. Thus these fibers can be used as acoustic sensors as for example in a sonar. They can also be used as electric field operated light modulators. However, for this application the fibers would be made with a cross section in the form of a 'D'. The core with its surrounding LiNbO, layer would be close to the flat portion of the 'D' shaped fiber. Two metal contacts would be deposited on the flat portion of the fiber on either side of the core. A voltage applied across these contacts will result in an electric field in the core region that can be used for modulating the optical properties of the LiNbO, layer. To our knowledge this is the first ever LiNbO, Cylinder Fiber made.

  20. Conformal microstrip arrays on cylinders

    NASA Astrophysics Data System (ADS)

    Ashkenazy, J.; Shtrikman, S.; Treves, D.

    1988-04-01

    Design and measured results for two X-band conformal microstrip arrays are presented. The two 4 x 4 arrays are built on the surface of a cylinder of small radius. They differ by the orientation of small radius. They differ by the orientation of the elements relative to the cylinder axis. The measured directivities and radiation patterns are in reasonable agreement with theoretical predictions.

  1. Carbon-carbon cylinder block

    NASA Technical Reports Server (NTRS)

    Ransone, Philip O. (Inventor)

    1998-01-01

    A lightweight cylinder block composed of carbon-carbon is disclosed. The use of carbon-carbon over conventional materials, such as cast iron or aluminum, reduces the weight of the cylinder block and improves thermal efficiency of the internal combustion reciprocating engine. Due to the negligible coefficient of thermal expansion and unique strength at elevated temperatures of carbon-carbon, the piston-to-cylinder wall clearance can be small, especially when the carbon-carbon cylinder block is used in conjunction with a carbon-carbon piston. Use of the carbon-carbon cylinder block has the effect of reducing the weight of other reciprocating engine components allowing the piston to run at higher speeds and improving specific engine performance.

  2. Electric fields and current densities under small Florida thunderstorms

    NASA Technical Reports Server (NTRS)

    Deaver, Lance E.; Krider, E. P.

    1991-01-01

    Results are presented of measurements of the electric field E and Maxwell current density that were performed simultaneously under and near small Florida thunderstorms. It is shown that the amplitude of JM is of the order of 1 nA/sq cm or less in the absence of precipitation and that there are regular time variations in JM during the intervals between lightning discharges that tend to have the same shapes after different discharges in different storms. It is argued that the major causes of time variations in JM between lightning discharges are currents that flow in the finitely conducting atmosphere in response to the field changes rather than rapid time variations in the strength of cloud current sources. The displacement current densities that are computed from the E records dominate JM except when there is precipitation, when E is large and steady, or when E is unusually noisy.

  3. Individual cylinder knock control by detecting cylinder pressure

    SciTech Connect

    Sawamoto, K.; Kawamura, Y.; Kita, T.; Matsushita, K.

    1987-01-01

    To improve available power, tolerance to variation in fuel octane number and high engine speed knock control, an individual cylinder knock control has been developed. Knock are detected by spark plug washer transducers, which indicate individual cylinder pressures.) Last year the authors read a paper entitled ''Cylinder Pressure Vibration Analysis Indicates Accurate Knock Detection''. They read continuously on the following items. Spark plug washer transducers - These are piezoelectric ceramic rings which fit beneath individual spark plugs. These can detect knock at high engine speed, and are very durable. Knock detection and control algorithm - Knock is indicated by the transducer's cylinder pressure vibration signal. When knock occurs in the cylinder, the ignition timing of the cylinder is controlled. During the transient condition, control response is fast by learning control. Fail safe - At transducer trouble, the ignition timing of the cylinder is controlled by other transducer signals. Electric control unit - It is included in NISSANs Electronic Concentrated Engine Control System (ECCS). Effects of this control - It improved WOT torque by 7-15%, torelance to variation in fuel octane number, and high engine speed control performance.

  4. Electrically Small Microstrip Quarter-Wave Monopole Antennas

    NASA Technical Reports Server (NTRS)

    Young, W. Robert

    2004-01-01

    Microstrip-patch-style antennas that generate monopole radiation patterns similar to those of quarter-wave whip antennas can be designed to have dimensions smaller than those needed heretofore for this purpose, by taking advantage of a feed configuration different from the conventional one. The large sizes necessitated by the conventional feed configuration have, until now, made such antennas impractical for frequencies below about 800 MHz: for example, at 200 MHz, the conventional feed configuration necessitates a patch diameter of about 8 ft (.2.4 m) . too large, for example, for mounting on the roof of an automobile or on a small or medium-size aircraft. By making it possible to reduce diameters to between a tenth and a third of that necessitated by the conventional feed configuration, the modified configuration makes it possible to install such antennas in places where they could not previously be installed and thereby helps to realize the potential advantages (concealment and/or reduction of aerodynamic drag) of microstrip versus whip antennas. In both the conventional approach and the innovative approach, a microstrip-patch (or microstrip-patch-style) antenna for generating a monopole radiation pattern includes an electrically conductive patch or plate separated from an electrically conductive ground plane by a layer of electrically insulating material. In the conventional approach, the electrically insulating layer is typically a printed-circuit board about 1/16 in. (.1.6 mm) thick. Ordinarily, a coaxial cable from a transmitter, receiver, or transceiver is attached at the center on the ground-plane side, the shield of the cable being electrically connected to the ground plane. In the conventional approach, the coaxial cable is mated with a connector mounted on the ground plane. The center pin of this connector connects to the center of the coaxial cable and passes through a hole in the ground plane and a small hole in the insulating layer and then connects

  5. Massless rotating fermions inside a cylinder

    SciTech Connect

    Ambruş, Victor E.; Winstanley, Elizabeth

    2015-12-07

    We study rotating thermal states of a massless quantum fermion field inside a cylinder in Minkowski space-time. Two possible boundary conditions for the fermion field on the cylinder are considered: the spectral and MIT bag boundary conditions. If the radius of the cylinder is sufficiently small, rotating thermal expectation values are finite everywhere inside the cylinder. We also study the Casimir divergences on the boundary. The rotating thermal expectation values and the Casimir divergences have different properties depending on the boundary conditions applied at the cylinder. This is due to the local nature of the MIT bag boundary condition, while the spectral boundary condition is nonlocal.

  6. Small-scale electrical resistivity tomography of wet fractured rocks.

    PubMed

    LaBrecque, Douglas J; Sharpe, Roger; Wood, Thomas; Heath, Gail

    2004-01-01

    This paper describes a series of experiments that tested the ability of the electrical resistivity tomography (ERT) method to locate correctly wet and dry fractures in a meso-scale model. The goal was to develop a method of monitoring the flow of water through a fractured rock matrix. The model was a four by six array of limestone blocks equipped with 28 stainless steel electrodes. Dry fractures were created by placing pieces of vinyl between one or more blocks. Wet fractures were created by injecting tap water into a joint between blocks. In electrical terms, the dry fractures are resistive and the wet fractures are conductive. The quantities measured by the ERT system are current and voltage around the outside edge of the model. The raw ERT data were translated to resistivity values inside the model using a three-dimensional Occam's inversion routine. This routine was one of the key components of ERT being tested. The model presented several challenges. First, the resistivity of both the blocks and the joints was highly variable. Second, the resistive targets introduced extreme changes the software could not precisely quantify. Third, the abrupt changes inherent in a fracture system were contrary to the smoothly varying changes expected by the Occam's inversion routine. Fourth, the response of the conductive fractures was small compared to the background variability. In general, ERT was able to locate correctly resistive fractures. Problems occurred, however, when the resistive fracture was near the edges of the model or when multiple fractures were close together. In particular, ERT tended to position the fracture closer to the model center than its true location. Conductive fractures yielded much smaller responses than the resistive case. A difference-inversion method was able to correctly locate these targets.

  7. 2-SR-based electrically small antenna for RFID applications

    NASA Astrophysics Data System (ADS)

    Paredes, Ferran; Zuffanelli, Simone; Aguilà, Pau; Zamora, Gerard; Martin, Ferran; Bonache, Jordi

    2016-04-01

    In this work, the 2-turn spiral resonator (2-SR) is proposed as an electrically small antenna for passive radio frequency identification (RFID) tags at the European ultra-high frequency (UHF) band. The radiation properties are studied in order to explore the viability of the 2-SR applied to tag antenna design. Based on analytical calculations, the radiation pattern is found to provide a cancelation of the radiation nulls. This results in a mitigation of the blind spots in the read range, which are present in typical UHF-RFID tags as an undesired feature. As a proof of concept, a passive tag of size 35 mm × 40 mm (λ 0/10 × λ 0/9) based on the 2-SR antenna is designed and fabricated. Good radiation efficiency (75 %) and a quasi-isotropic radiation pattern are obtained. The experimental tag read range for different directions is in good agreement with the simulation results. The measured read range exhibits maximum and minimum values of 6.7 and 3.5 m, respectively.

  8. Blower Cooling of Finned Cylinders

    NASA Technical Reports Server (NTRS)

    Schey, Oscar W; Ellerbrock, Herman H , Jr

    1937-01-01

    Several electrically heated finned steel cylinders enclosed in jackets were cooled by air from a blower. The effect of the air conditions and fin dimensions on the average surface heat-transfer coefficient q and the power required to force the air around the cylinders were determined. Tests were conducted at air velocities between the fins from 10 to 130 miles per hour and at specific weights of the air varying from 0.046 to 0.074 pound per cubic foot. The fin dimensions of the cylinders covered a range in pitches from 0.057 to 0.25 inch average fin thicknesses from 0.035 to 0.04 inch, and fin widths from 0.67 to 1.22 inches.

  9. Quick release engine cylinder

    DOEpatents

    Sunnarborg, Duane A.

    2000-01-01

    A quick release engine cylinder allows optical access to an essentially unaltered combustion chamber, is suitable for use with actual combustion processes, and is amenable to rapid and repeated disassembly and cleaning. A cylinder member, adapted to constrain a piston to a defined path through the cylinder member, sealingly engages a cylinder head to provide a production-like combustion chamber. A support member mounts with the cylinder member. The support-to-cylinder mounting allows two relationships therebetween. In the first mounting relationship, the support engages the cylinder member and restrains the cylinder against the head. In the second mounting relationship, the cylinder member can pass through the support member, moving away from the head and providing access to the piston-top and head.

  10. Small animal electric and magnetic field exposure systems. Final report

    SciTech Connect

    Patterson, R.C.; Dietrich, F.M.

    1993-10-01

    Laboratory evaluation of electric and magnetic fields (EMF) and cancer in animals requires exposure of relatively large numbers of animals, usually rats or mice, to 60-Hz fields under very well controlled conditions for periods of up to two years. This report describes two exposure systems, the first of which is based on modifications of an existing electric field exposure system to include magnetic field exposure capability. In this system, each module houses 576--768 mice, which can be exposed to electric field levels of up to 100 kV/m and magnetic field levels of up to 10 Gauss. When a module was operated at 10 Gauss, measured levels of noise and vibration fell substantially below the detection threshold for humans. Moreover, temperature rise in the coils did not exceed 12{degrees}C at the 10 Gauss level. Specifications and test results for the second system, which provides magnetic field exposure capability only, are similar, except that each module houses 624--780 mice. After installation of the second system at the West Los Angeles Veterans Medical Center in Los Angeles, California, additional results were obtained. This report provides a complete description of the engineering design, specifications, and test results for the completed systems.

  11. 6. FLYWHEEL FOR THE 32/28 STRUCTURAL MILL. THE SMALL ELECTRIC ...

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

    6. FLYWHEEL FOR THE 32/28 STRUCTURAL MILL. THE SMALL ELECTRIC MOTOR IN FOREGROUND MAY HAVE BEEN USED TO HELP START THE MILL. - U.S. Steel Homestead Works, Structural Mill, Along Monongahela River, Homestead, Allegheny County, PA

  12. 75 FR 10873 - Energy Conservation Program: Energy Conservation Standards for Small Electric Motors

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-09

    ...The U.S. Department of Energy (DOE) is adopting energy conservation standards for small electric motors. DOE has determined that these standards will result in significant conservation of energy, and are technologically feasible and economically...

  13. Speed control of a small turbine using electrical loading.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Small wind turbines with permanent magnet alternators (PMA) seldom have active speed control systems. The turbines rely on passive mechanisms such as furling and/or blade flutter to control the rotational speed. These passive methods cause high mechanical stresses and undesirable noise. One metho...

  14. Electrical stimulation of a small brain area reversibly disrupts consciousness.

    PubMed

    Koubeissi, Mohamad Z; Bartolomei, Fabrice; Beltagy, Abdelrahman; Picard, Fabienne

    2014-08-01

    The neural mechanisms that underlie consciousness are not fully understood. We describe a region in the human brain where electrical stimulation reproducibly disrupted consciousness. A 54-year-old woman with intractable epilepsy underwent depth electrode implantation and electrical stimulation mapping. The electrode whose stimulation disrupted consciousness was between the left claustrum and anterior-dorsal insula. Stimulation of electrodes within 5mm did not affect consciousness. We studied the interdependencies among depth recording signals as a function of time by nonlinear regression analysis (h(2) coefficient) during stimulations that altered consciousness and stimulations of the same electrode at lower current intensities that were asymptomatic. Stimulation of the claustral electrode reproducibly resulted in a complete arrest of volitional behavior, unresponsiveness, and amnesia without negative motor symptoms or mere aphasia. The disruption of consciousness did not outlast the stimulation and occurred without any epileptiform discharges. We found a significant increase in correlation for interactions affecting medial parietal and posterior frontal channels during stimulations that disrupted consciousness compared with those that did not. Our findings suggest that the left claustrum/anterior insula is an important part of a network that subserves consciousness and that disruption of consciousness is related to increased EEG signal synchrony within frontal-parietal networks.

  15. An Analytical Performance Assessment of a Fuel Cell-powered, Small Electric Airplane

    NASA Technical Reports Server (NTRS)

    Berton, Jeffrey J.; Freeh, Joshua E.; Wickenheiser, Timothy J.

    2003-01-01

    Rapidly emerging fuel cell power technologies may be used to launch a new revolution of electric propulsion systems for light aircraft. Future small electric airplanes using fuel cell technologies hold the promise of high reliability, low maintenance, low noise, and with exception of water vapor zero emissions. This paper describes an analytical feasibility and performance assessment conducted by NASA's Glenn Research Center of a fuel cell-powered, propeller-driven, small electric airplane based on a model of the MCR 01 two-place kitplane.

  16. PHOBOS Exploration using Two Small Solar Electric Propulsion Spacecraft

    NASA Technical Reports Server (NTRS)

    Lang, Jared J.; Baker, John D.; Castillo-Rogez, Julie C.; McElrath, Timothy P.; Piacentine, Jamie S.; Snyder, J. Steve

    2012-01-01

    Primitive bodies are exciting targets for exploration as they provide clues to the early Solar system conditions and dynamical evolution. The two moons of Mars are particularly interesting because of their proximity to an astrobiological target. However, after four decades of Mars exploration, their origin and nature remain enigmatic. In addition, when considering the long-term objectives of the flexible path for the potential human exploration to Mars, Phobos and Deimos present exciting intermediate opportunities without the complication and expense of landing and ascending from the surface. As interest in these targets for the next frontier of human exploration grows, characterization missions designed specifically to examine surface properties, landing environments, and surface mapping prior to human exploration are becoming increasingly important. A precursor mission concept of this sort has been developed using two identical spacecraft designed from low cost, flight proven and certified off-the-shelf component and utilizing Solar Electric Propulsion (SEP) to orbit both targets as secondary payloads launched aboard any NASA or GTO launch. This precursor mission has the potential to address both precursor measurements that are strategic knowledge gaps and decadal science, including soil physical properties at the global and local (human) scale and the search for in situ resources.

  17. Some design considerations for small piezo-electrical ceramic transducers

    NASA Astrophysics Data System (ADS)

    Rijnja, H. A. J.

    1989-07-01

    The design parameters and the characteristics of small omnidirectional transducers, to be applied under water as projectors in the frequency range of about 1 kHz to 100 kHz and as hydrophones from very low frequencies up to again 100kHz are described. The transducers are constructed with piezoelectrical ceramic materials in the shape of hollow spheres, end capped tubes or piston (Tonpilz) elements. The highest source levels are obtained with spherical transducers as single omnidirectional sound sources. If larger arrays of sources are applied the array should be composed of single ended Tonpilz elements. The most sensitive receivers (hydrophones) are obtained with tangentially polarized end-capped tubes.

  18. Thin magnetic conductor substrate for placement-immune, electrically-small antennas.

    SciTech Connect

    Eubanks, Travis Wayne; McDonald, Jacob J.; Loui, Hung

    2011-09-01

    An antenna is considered to be placement-immune when the antenna operates effectively regardless of where it is placed. By building antennas on magnetic conductor materials, the radiated fields will be positively reinforced in the desired radiation direction instead of being negatively affected by the environment. Although this idea has been discussed thoroughly in theoretical research, the difficulty in building thin magnetic conductor materials necessary for in-phase field reflections prevents this technology from becoming more widespread. This project's purpose is to build and measure an electrically-small antenna on a new type of non-metallic, thin magnetic conductor. This problem has not been previously addressed because non-metallic, thin magnetic conductor materials have not yet been discovered. This work proposed the creation of an artificial magnetic conductor (AMC) with in-phase field reflections without using internal electric conductors, the placement of an electrically-small antenna on this magnetic conductor, and the development of a transmit-receive system that utilizes the substrate and electrically-small antenna. By not using internal electric conductors to create the AMC, the substrate thickness can be minimized. The electrically-small antenna will demonstrate the substrate's ability to make an antenna placement immune, and the transmit-receive system combines both the antenna and the substrate while adding a third layer of system complexity to demonstrate the complete idea.

  19. Slow light and band gaps in metallodielectric cylinder arrays.

    PubMed

    Shainline, Jeffrey M; Xu, Jimmy

    2009-05-25

    We consider two-dimensional three-component photonic crystals wherein one component is modeled as a drude-dispersive metal. It is found that the dispersion relation of light in this environment depends critically on the configuration of the metallic and dielectric components. In particular, for the case of an incident electromagnetic wave with electric field vector parallel to the axis of the cylinders it is shown that the presence of dielectric shells covering the metallic cylinders leads to a closing of the structural band gap with increased filling factor, as would be expected for a purely dielectric photonic crystal. For the same polarization, the photonic band structure of an array of metallic shell cylinders with dielectric cores do not show the closing of the structural band gap with increased filling factor of the metallic component. In this geometry, the photonic band structure contains bands with very small values of group velocity with some bands having a maximum of group velocity as small as .05c.

  20. Electrostatic field between non-concentric cylinders

    SciTech Connect

    Garcia, M

    2000-01-10

    This report describes a closed-form solution to the electrostatic potential, and the electric field, between non-concentric cylinders, with the inner cylinder charged and the outer cylinder grounded. This problem is an abstraction of the situation of an electron beam within a drift tube. Capacitive and surface current probes on the inner wall of the outer cylinder are used to detect the asymmetry of the field when the beam is off center. The solution of this problem allows for a quantitative relationship between probe-array signals and beam deflection. probe-arrays of this type are called ''beam bugs'' at LLNL. The solution described here is suggested by the analysis presented in [3]. The essential point is that the 2D potential for a line source decreases along a radius as the logarithm of the distance. The non-concentric cylinder problem has a unique profile of this type for each ray from ({rho}, {sigma}) linking the inner cylinder at equipotential V{sub 2}, and the outer cylinder at equipotential 0.

  1. The measurement of maximum cylinder pressures

    NASA Technical Reports Server (NTRS)

    Hicks, Chester W

    1929-01-01

    The work presented in this report was undertaken at the Langley Memorial Aeronautical Laboratory of the National Advisory Committee for Aeronautics to determine a suitable method for measuring the maximum pressures occurring in aircraft engine cylinders. The study and development of instruments for the measurement of maximum cylinder pressures has been conducted in connection with carburetor and oil engine investigations on a single cylinder aircraft-type engine. Five maximum cylinder-pressure devices have been designed, and tested, in addition to the testing of three commercial indicators. Values of maximum cylinder pressures are given as obtained with various indicators for the same pressures and for various kinds and values of maximum cylinder pressures, produced chiefly by variation of the injection advance angle in high-speed oil engine. The investigations indicate that the greatest accuracy in determining maximum cylinder pressures can be obtained with an electric, balanced-pressure, diaphragm or disk-type indicator so constructed as to have a diaphragm or disk of relatively large area and minimum seat width and mass.

  2. Cylinder monitoring program

    SciTech Connect

    Alderson, J.H.

    1991-12-31

    Cylinders containing depleted uranium hexafluoride (UF{sub 6}) in storage at the Department of Energy (DOE) gaseous diffusion plants, managed by Martin Marietta Energy Systems, Inc., are being evaluated to determine their expected storage life. Cylinders evaluated recently have been in storage service for 30 to 40 years. In the present environment, the remaining life for these storage cylinders is estimated to be 30 years or greater. The group of cylinders involved in recent tests will continue to be monitored on a periodic basis, and other storage cylinders will be observed as on a statistical sample population. The program has been extended to all types of large capacity UF{sub 6} cylinders.

  3. Collapsing bacterial cylinders

    NASA Astrophysics Data System (ADS)

    Betterton, M. D.; Brenner, Michael P.

    2001-12-01

    Under special conditions bacteria excrete an attractant and aggregate. The high density regions initially collapse into cylindrical structures, which subsequently destabilize and break up into spherical aggregates. This paper presents a theoretical description of the process, from the structure of the collapsing cylinder to the spacing of the final aggregates. We show that cylindrical collapse involves a delicate balance in which bacterial attraction and diffusion nearly cancel, leading to corrections to the collapse laws expected from dimensional analysis. The instability of a collapsing cylinder is composed of two distinct stages: Initially, slow modulations to the cylinder develop, which correspond to a variation of the collapse time along the cylinder axis. Ultimately, one point on the cylinder pinches off. At this final stage of the instability, a front propagates from the pinch into the remainder of the cylinder. The spacing of the resulting spherical aggregates is determined by the front propagation.

  4. A Study of Gas Economizing Pneumatic Cylinder

    NASA Astrophysics Data System (ADS)

    Li, T. C.; Wu, H. W.; Kuo, M. J.

    2006-10-01

    The pneumatic cylinder is the most typical actuator in the pneumatic equipment, and its mechanism is so simple that it is often used to operate point to point driving without the feedback loop in various automatic machines. But, the energy efficiency of pneumatic system is very poor compared with electrical systems and hydraulic systems. So, it is very important to discuss the energy saving for the pneumatic cylinder systems. In this thesis, we proposed three methods to apply the reduction in the air consumed for pneumatic cylinder systems. An air charge accumulator is used to absorb the exhausted compress air and a boost valve boosted the air to the higher pressure for used again. From the experiments, the direct used cylinder exhaust air may save about 40% of compress air.

  5. Delamination of Composite Cylinders

    NASA Astrophysics Data System (ADS)

    Davies, Peter; Carlsson, Leif A.

    The delamination resistance of filament wound glass/epoxy cylinders has been characterized for a range of winding angles and fracture mode ratios using beam fracture specimens. The results reveal that the delamination fracture resistance increases with increasing winding angle and mode II (shear) fraction (GΠ/G). It was also found that interlaced fiber bundles in the filament wound cylinder wall acted as effective crack arresters in mode I loading. To examine the sensitivity of delamina-tion damage on the strength of the cylinders, external pressure tests were performed on filament-wound glass/epoxy composite cylinders with artificial defects and impact damage. The results revealed that the cylinder strength was insensitive to the presence of single delaminations but impact damage caused reductions in failure pressure. The insensitivity of the failure pressure to a single delamination is attributed to the absence of buckling of the delaminated sublaminates before the cylinder wall collapsed. The impacted cylinders contained multiple delaminations, which caused local reduction in the compressive load capability and reduction in failure pressure. The response of glass/epoxy cylinders was compared to impacted carbon reinforced cylinders. Carbon/epoxy is more sensitive to damage but retains higher implosion resistance while carbon/PEEK shows the opposite trend.

  6. Maximal liquid bridges between horizontal cylinders.

    PubMed

    Cooray, Himantha; Huppert, Herbert E; Neufeld, Jerome A

    2016-08-01

    We investigate two-dimensional liquid bridges trapped between pairs of identical horizontal cylinders. The cylinders support forces owing to surface tension and hydrostatic pressure that balance the weight of the liquid. The shape of the liquid bridge is determined by analytically solving the nonlinear Laplace-Young equation. Parameters that maximize the trapping capacity (defined as the cross-sectional area of the liquid bridge) are then determined. The results show that these parameters can be approximated with simple relationships when the radius of the cylinders is small compared with the capillary length. For such small cylinders, liquid bridges with the largest cross-sectional area occur when the centre-to-centre distance between the cylinders is approximately twice the capillary length. The maximum trapping capacity for a pair of cylinders at a given separation is linearly related to the separation when it is small compared with the capillary length. The meniscus slope angle of the largest liquid bridge produced in this regime is also a linear function of the separation. We additionally derive approximate solutions for the profile of a liquid bridge, using the linearized Laplace-Young equation. These solutions analytically verify the above-mentioned relationships obtained for the maximization of the trapping capacity.

  7. Maximal liquid bridges between horizontal cylinders

    NASA Astrophysics Data System (ADS)

    Cooray, Himantha; Huppert, Herbert E.; Neufeld, Jerome A.

    2016-08-01

    We investigate two-dimensional liquid bridges trapped between pairs of identical horizontal cylinders. The cylinders support forces owing to surface tension and hydrostatic pressure that balance the weight of the liquid. The shape of the liquid bridge is determined by analytically solving the nonlinear Laplace-Young equation. Parameters that maximize the trapping capacity (defined as the cross-sectional area of the liquid bridge) are then determined. The results show that these parameters can be approximated with simple relationships when the radius of the cylinders is small compared with the capillary length. For such small cylinders, liquid bridges with the largest cross-sectional area occur when the centre-to-centre distance between the cylinders is approximately twice the capillary length. The maximum trapping capacity for a pair of cylinders at a given separation is linearly related to the separation when it is small compared with the capillary length. The meniscus slope angle of the largest liquid bridge produced in this regime is also a linear function of the separation. We additionally derive approximate solutions for the profile of a liquid bridge, using the linearized Laplace-Young equation. These solutions analytically verify the above-mentioned relationships obtained for the maximization of the trapping capacity.

  8. Industrial Education. Mini-Course Cluster: Bikes, Electricity, Small Engines. [Grade 9].

    ERIC Educational Resources Information Center

    Parma City School District, OH.

    Part of a series of curriculum guides dealing with industrial education in junior high schools, this guide provides three units to be used in a one semester course in grade 9 on the subjects of bikes, electricity, and small engines. The section on bicycles is divided into two parts, mechanical and power (i.e. motorcycles) and covers the topics of…

  9. Small Wind Electric Systems: A Guide Produced for the Tennessee Valley Authority (Revised) (Brochure)

    SciTech Connect

    Not Available

    2009-06-01

    Small Wind Electric Systems: A Guide Produced for the Tennessee Valley Authority provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and their economics. Topics discussed in the guide include how to make a home more energy efficient, how to choose the correct turbine size, the parts of a wind electric system, how to determine whether enough wind resource exists, how to choose the best site for a turbine, how to connect a system to the utility grid, and whether it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a regional wind resource map and a list of incentives and contacts for more information.

  10. Static Pressure Distribution on Long Cylinders as Function of Angle of Yaw and Reynolds Number,

    DTIC Science & Technology

    1983-07-01

    pressure coefficient around a perpendicularly aligned cylinder xiv 1. INTRODUCTION The problem addressed in this investigation is that of the static...pressure distribution developed on the surface of a long circular cylinder immersed in a laminar flow at small angles of yaw. The interest in this problem ...cylinder. The problem of flow over yawed cylinders or cylinders at angle of attack first attracted attention in the 1950’s. At that time, r esearch was

  11. A Sequence of Cylinders

    ERIC Educational Resources Information Center

    Johnson, Erica

    2006-01-01

    Hoping to develop in her students an understanding of mathematics as a way of thinking more than a way of doing, the author of this article describes how her students worked on a spatial reasoning problem stemming from an iteratively constructed sequence of cylinders. She presents an activity of making cylinders out of paper models, and for every…

  12. MMS Multipoint electric field observations of small-scale magnetic holes

    NASA Astrophysics Data System (ADS)

    Goodrich, Katherine A.; Ergun, Robert E.; Wilder, Frederick D.; Burch, James; Torbert, Roy; Khotyaintsev, Yuri; Lindqvist, Per-Arne; Russell, Christopher; Strangeway, Robert; Magnes, Werner; Gershman, Daniel; Giles, Barbara; Nakamura, Rumi; Stawarz, Julia; Holmes, Justin; Sturner, Andrew; Malaspina, David M.

    2016-06-01

    Small-scale magnetic holes (MHs), local depletions in magnetic field strength, have been observed multiple times in the Earth's magnetosphere in the bursty bulk flow (BBF) braking region. This particular subset of MHs has observed scale sizes perpendicular to the background magnetic field (B) less than the ambient ion Larmor radius (ρi). Previous observations by Time History of Events and Macroscale Interactions during Substorms (THEMIS) indicate that this subset of MHs can be supported by a current driven by the E × B drift of electrons. Ions do not participate in the E × B drift due to the small-scale size of the electric field. While in the BBF braking region, during its commissioning phase, the Magnetospheric Multiscale (MMS) spacecraft observed a small-scale MH. The electric field observations taken during this event suggest the presence of electron currents perpendicular to the magnetic field. These observations also suggest that these currents can evolve to smaller spatial scales.

  13. Improved electric energy production of solar cell using small silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Wang, X. Y.; Li, H. F.; Shi, S.; Wang, J. L.

    2017-03-01

    The influence of small Ag nanoparticles (NPs) on the all-day electric energy production of solar cells has been investigated. The small Ag NPs were deposited on the cell surface by the magnetron sputtering system. The cell without NPs is used as a reference cell. The external quantum efficiency (EQE) curves indicate that the performance of cell with 8% nanoparticle coverage is better than that of other cells in the long wavelength band. The maximum power-angle curves indicate that the small Ag NPs can effectively improve the all-day electric energy production of solar cell. Comparing with the values of reference cell, the half peak height of maximum power for cell optimized increases by 65%, and the half peak breadth of maximum power for cell optimized broadens by 3%. The enhancements of optimum operating current and optimum operating voltage lead directly to the enhancement of maximum power.

  14. Theory of interacting dislocations on cylinders

    NASA Astrophysics Data System (ADS)

    Amir, Ariel; Paulose, Jayson; Nelson, David R.

    2013-04-01

    We study the mechanics and statistical physics of dislocations interacting on cylinders, motivated by the elongation of rod-shaped bacterial cell walls and cylindrical assemblies of colloidal particles subject to external stresses. The interaction energy and forces between dislocations are solved analytically, and analyzed asymptotically. The results of continuum elastic theory agree well with numerical simulations on finite lattices even for relatively small systems. Isolated dislocations on a cylinder act like grain boundaries. With colloidal crystals in mind, we show that saddle points are created by a Peach-Koehler force on the dislocations in the circumferential direction, causing dislocation pairs to unbind. The thermal nucleation rate of dislocation unbinding is calculated, for an arbitrary mobility tensor and external stress, including the case of a twist-induced Peach-Koehler force along the cylinder axis. Surprisingly rich phenomena arise for dislocations on cylinders, despite their vanishing Gaussian curvature.

  15. Steady streaming around a cylinder pair

    NASA Astrophysics Data System (ADS)

    Coenen, W.

    2016-11-01

    The steady streaming motion that appears around a pair of circular cylinders placed in a small-amplitude oscillatory flow is considered. Attention is focused on the case where the Stokes layer thickness at the surface of the cylinders is much smaller than the cylinder radius, and the streaming Reynolds number is of order unity or larger. In that case, the steady streaming velocity that persists at the edge of the Stokes layer can be imposed as a boundary condition to numerically solve the outer streaming motion that it drives in the bulk of the fluid. It is investigated how the gap width between the cylinders and the streaming Reynolds number affect the flow topology. The results are compared against experimental observations.

  16. Why intra-epidermal electrical stimulation achieves stimulation of small fibres selectively: a simulation study

    NASA Astrophysics Data System (ADS)

    Motogi, Jun; Sugiyama, Yukiya; Laakso, Ilkka; Hirata, Akimasa; Inui, Koji; Tamura, Manabu; Muragaki, Yoshihiro

    2016-06-01

    The in situ electric field in the peripheral nerve of the skin is investigated to discuss the selective stimulation of nerve fibres. Coaxial planar electrodes with and without intra-epidermal needle tip were considered as electrodes of a stimulator. From electromagnetic analysis, the tip depth of the intra-epidermal electrode should be larger than the thickness of the stratum corneum, the electrical conductivity of which is much lower than the remaining tissue. The effect of different radii of the outer ring electrode on the in situ electric field is marginal. The minimum threshold in situ electric field (rheobase) for free nerve endings is estimated to be 6.3 kV m-1. The possible volume for electrostimulation, which can be obtained from the in situ electric field distribution, becomes deeper and narrower with increasing needle depth, suggesting that possible stimulation sites may be controlled by changing the needle depth. The injection current amplitude should be adjusted when changing the needle depth because the peak field strength also changes. This study shows that intra-epidermal electrical stimulation can achieve stimulation of small fibres selectively, because Aβ-, Aδ-, and C-fibre terminals are located at different depths in the skin.

  17. Implementation of an Open-Loop Rule-Based Control Strategy for a Hybrid-Electric Propulsion System On a Small RPA

    DTIC Science & Technology

    2011-03-01

    ix List of Figures Figure 1: Series hybrid configuration [12... Electromotive Force (V) Um Electric Motor Open Circuit Voltage (V) u Clutch Displacement Angle (rad) Vbat Battery Voltage (V) Vd Cylinder Displacement...of three areas: series hybrid, parallel hybrid, and the power-split hybrid. A great number of these designs incorporate the gasoline internal

  18. Tandem Cylinder Noise Predictions

    NASA Technical Reports Server (NTRS)

    Lockhard, David P.; Khorrami, Mehdi R.; CHoudhari, Meelan M.; Hutcheson, Florence V.; Brooks, Thomas F.; Stead, Daniel J.

    2007-01-01

    In an effort to better understand landing-gear noise sources, we have been examining a simplified configuration that still maintains some of the salient features of landing-gear flow fields. In particular, tandem cylinders have been studied because they model a variety of component level interactions. The present effort is directed at the case of two identical cylinders spatially separated in the streamwise direction by 3.7 diameters. Experimental measurements from the Basic Aerodynamic Research Tunnel (BART) and Quiet Flow Facility (QFF) at NASA Langley Research Center (LaRC) have provided steady surface pressures, detailed off-surface measurements of the flow field using Particle Image Velocimetry (PIV), hot-wire measurements in the wake of the rear cylinder, unsteady surface pressure data, and the radiated noise. The experiments were conducted at a Reynolds number of 166 105 based on the cylinder diameter. A trip was used on the upstream cylinder to insure a fully turbulent shedding process and simulate the effects of a high Reynolds number flow. The parallel computational effort uses the three-dimensional Navier-Stokes solver CFL3D with a hybrid, zonal turbulence model that turns off the turbulence production term everywhere except in a narrow ring surrounding solid surfaces. The current calculations further explore the influence of the grid resolution and spanwise extent on the flow and associated radiated noise. Extensive comparisons with the experimental data are used to assess the ability of the computations to simulate the details of the flow. The results show that the pressure fluctuations on the upstream cylinder, caused by vortex shedding, are smaller than those generated on the downstream cylinder by wake interaction. Consequently, the downstream cylinder dominates the noise radiation, producing an overall directivity pattern that is similar to that of an isolated cylinder. Only calculations based on the full length of the model span were able to

  19. On the problem of designing small spacecraft with electric propulsion power plants for studying minor bodies of the Solar System

    NASA Astrophysics Data System (ADS)

    Kulkov, V. M.; Egorov, Yu. G.; Krainov, A. M.; Shakhanov, A. E.; Elnikov, R. V.

    2016-12-01

    Aspects of the design of small spacecraft with electric propulsion power plants for investigating minor bodies in the Solar System are examined. The results of design and ballistic analysis of transfer into an orbit of terrestrial asteroids using electric propulsion thrusters are given. The possible concept design of the spacecraft is determined and the structure of a small spacecraft with an electric propulsion power plant is presented. Parameters of the electric propulsion power plant of a small spacecraft for a flight to the minor bodies of the Solar System are estimated.

  20. Dopant Cylinder Lifetime Monitor

    NASA Astrophysics Data System (ADS)

    Bishop, Steve; Wodjenski, Michael; Kaim, Robert; Lurcott, Steve; McManus, Jim; Smith, Gordon

    2006-11-01

    The cost of consumable materials is a significant component in the cost of implanter operation. With the higher cost of sub-atmospheric gas alternatives it is increasingly important to accurately monitor its usage. The ATMI® SDS® GasGauge™ monitoring system accurately monitors gas level in four cylinders simultaneously, throughout their lifetime, in order to optimize usage of gas and related implanter productivity. This paper displays how the GasGauge monitoring system accurately monitors the cylinder contents in SDS®, VAC® and high pressure gas cylinders. Internal and customer test data is also presented to verify these claims.

  1. Indicator system provides complete data of engine cylinder pressure variation

    NASA Technical Reports Server (NTRS)

    Mc Jones, R. W.; Morgan, N. E.

    1966-01-01

    Varying reference pressure used together with a balanced pressure pickup /a diaphragm switch/ to switch the electric output of the pressure transducer in a reference pressure line obtains precise engine cylinder pressure data from a high speed internal combustion engine.

  2. Simulation of a small molecule analogue of a lithium ionomer in an external electric field

    SciTech Connect

    Waters, Sara M.; McCoy, John D. Brown, Jonathan R.; Frischknecht, Amalie L.

    2014-01-07

    We have investigated the ion dynamics in lithium-neutralized 2-pentylheptanoic acid, a small molecule analogue of a precise poly(ethylene-co-acrylic acid) lithium ionomer. Atomistic molecular dynamics simulations were performed in an external electric field. The electric field causes alignment of the ionic aggregates along the field direction. The energetic response of the system to an imposed oscillating electric field for a wide range of frequencies was tracked by monitoring the coulombic contribution to the energy. The susceptibility found in this manner is a component of the dielectric susceptibility typically measured experimentally. A dynamic transition is found and the frequency associated with this transition varies with temperature in an Arrhenius manner. The transition is observed to be associated with rearrangements of the ionic aggregates.

  3. Modeling of plasma in a hybrid electric propulsion for small satellites

    NASA Astrophysics Data System (ADS)

    Jugroot, Manish; Christou, Alex

    2016-09-01

    As space flight becomes more available and reliable, space-based technology is allowing for smaller and more cost-effective satellites to be produced. Working in large swarms, many small satellites can provide additional capabilities while reducing risk. These satellites require efficient, long term propulsion for manoeuvres, orbit maintenance and de-orbiting. The high exhaust velocity and propellant efficiency of electric propulsion makes it ideally suited for low thrust missions. The two dominant types of electric propulsion, namely ion thrusters and Hall thrusters, excel in different mission types. In this work, a novel electric hybrid propulsion design is modelled to enhance understanding of key phenomena and evaluate performance. Specifically, the modelled hybrid thruster seeks to overcome issues with existing Ion and Hall thruster designs. Scaling issues and optimization of the design will be discussed and will investigate a conceptual design of a hybrid spacecraft plasma engine.

  4. Performance of a Fuel-Cell-Powered, Small Electric Airplane Assessed

    NASA Technical Reports Server (NTRS)

    Berton, Jeffrey J.

    2004-01-01

    Rapidly emerging fuel-cell-power technologies may be used to launch a new revolution of electric propulsion systems for light aircraft. Future small electric airplanes using fuel cell technologies hold the promise of high reliability, low maintenance, low noise, and - with the exception of water vapor - zero emissions. An analytical feasibility and performance assessment was conducted by NASA Glenn Research Center's Airbreathing Systems Analysis Office of a fuel-cell-powered, propeller-driven, small electric airplane based on a model of the MCR-01 two-place kitplane (Dyn'Aero, Darois, France). This assessment was conducted in parallel with an ongoing effort by the Advanced Technology Products Corporation and the Foundation for Advancing Science and Technology Education. Their project - partially funded by a NASA grant - is to design, build, and fly the first manned, continuously propelled, nongliding electric airplane. In our study, an analytical performance model of a proton exchange membrane (PEM) fuel cell propulsion system was developed and applied to a notional, two-place light airplane modeled after the MCR-01 kitplane. The PEM fuel cell stack was fed pure hydrogen fuel and humidified ambient air via a small automotive centrifugal supercharger. The fuel cell performance models were based on chemical reaction analyses calibrated with published data from the fledgling U.S. automotive fuel cell industry. Electric propeller motors, rated at two shaft power levels in separate assessments, were used to directly drive a two-bladed, variable-pitch propeller. Fuel sources considered were compressed hydrogen gas and cryogenic liquid hydrogen. Both of these fuel sources provided pure, contaminant-free hydrogen for the PEM cells.

  5. Disassembly properties and material characterisation of household small waste electric and electronic equipment.

    PubMed

    Bovea, María D; Pérez-Belis, Victoria; Ibáñez-Forés, Valeria; Quemades-Beltrán, Pilar

    2016-07-01

    This paper is focused on characterising small waste electric and electronic equipment, specifically small household appliances, from two different points of views: disassembly properties and material identification. The sample for this characterisation was obtained from a selective collection campaign organised in Castellón de la Plana (Spain). A total amount of 833.7kg (749 units) of small waste electric and electronic equipment was collected, of which 23.3% by weight and 22.4% by units belonged to the subcategory household equipment. This subcategory, composed of appliances such as vacuum cleaners, toasters, sandwich makers, hand blenders, juicers, coffee makers, hairdryers, scales, irons and heaters, was first disassembled in order to analyse different aspects of the disassembly process for each equipment type: type of joints, ease of identification of materials, ease of access to joints for extracting components, ease of separation of components from the whole, uniformity of tools needed for the disassembly process and possibility of reassembly after disassembly. Results show that the most common joints used in these equipment types are snap-fits and screws, although some permanent joints have also been identified. Next, the material composition of each component of each appliance belonging to each equipment type was identified visually and with additional mechanical trials and testing. It can be observed that plastic and electric/electronic components are present in all the equipment types analysed and are also the material fractions that appear with higher percentages in the material composition: 41.1wt% and 39.1wt% for the plastic fraction and electric/electronic components, respectively. The most common plastics are: polypropylene (PP), acrylonitrile butadiene styrene (ABS) and polycarbonate (PC), while the most common electric/electronic components are: cable, plug and printed circuit boards. Results also show that disassembly properties and material

  6. The performance of solar thermal electric power systems employing small heat engines

    NASA Technical Reports Server (NTRS)

    Pons, R. L.

    1980-01-01

    The paper presents a comparative analysis of small (10 to 100 KWe) heat engines for use with a solar thermal electric system employing the point-focusing, distributed receiver (PF-DR) concept. Stirling, Brayton, and Rankine cycle engines are evaluated for a nominal overall system power level of 1 MWe, although the concept is applicable to power levels up to at least 10 MWe. Multiple concentrators are electrically connected to achieve the desired plant output. Best performance is achieved with the Stirling engine, resulting in a system Levelized Busbar Energy Cost of just under 50 mills/kWH and a Capital Cost of $900/kW, based on the use of mass-produced components. Brayton and Rankine engines show somewhat less performance but are viable alternatives with particular benefits for special applications. All three engines show excellent performance for the small community application.

  7. Modeling of sharp change in magnetic hysteresis behavior of electrical steel at small plastic deformation

    SciTech Connect

    Sablik, M.J.; Rios, S.; Landgraf, F.J.G.; Yonamine, T.; Campos, M.F. de

    2005-05-15

    In 2.2% Si electrical steel, the magnetic hysteresis behavior is sharply sheared by a rather small plastic deformation (0.5%). A modification to the Jiles-Atherton hysteresis model makes it possible to model magnetic effects of plastic deformation. In this paper, with this model, it is shown how a narrow hysteresis with an almost steplike hysteresis curve for an undeformed specimen is sharply sheared by plastic deformation. Computed coercivity and hysteresis loss show a sharp step to higher values at small strain due to an n=1/2 power law dependence on residual strain. The step is seen experimentally.

  8. Small scale gasification of short rotation coppice willow for electricity generation

    SciTech Connect

    Dawson, W.M.; Forbes, G.; McCracken, A.R.

    1996-12-31

    Conversion technologies for wood chip produced from short rotation coppice willow have concentrated on small dispersed systems suitable for the farm structure found in Northern Ireland. The development of a 100 kW downdraft gasification, combined heat and power system identified a number of problems including fuel characteristics and gas clean up. Modifications to fuel feed systems, hearth design and particulate and tar removal methods have resulted consistent production of high quality gas for the diesel engine used for electricity generation.

  9. Gas Cylinder Safety, Course 9518

    SciTech Connect

    Glass, George

    2016-10-27

    This course, Gas Cylinder Safety (#9518), presents an overview of the hazards and controls associated with handling, storing, using, and transporting gas cylinders. Standard components and markings of gas cylinders are also presented, as well as the process for the procurement, delivery, and return of gas cylinders at Los Alamos National Laboratory (LANL).

  10. Relativistic Bessel cylinders

    NASA Astrophysics Data System (ADS)

    Krisch, J. P.; Glass, E. N.

    2014-10-01

    A set of cylindrical solutions to Einstein's field equations for power law densities is described. The solutions have a Bessel function contribution to the metric. For matter cylinders regular on axis, the first two solutions are the constant density Gott-Hiscock string and a cylinder with a metric Airy function. All members of this family have the Vilenkin limit to their mass per length. Some examples of Bessel shells and Bessel motion are given.

  11. Relativistic Bessel Cylinders

    NASA Astrophysics Data System (ADS)

    Krisch, J. P.; Glass, E. N.

    2014-11-01

    A set of cylindrical solutions to Einstein's field equations for power law densities is described. The solutions have a Bessel function contribution to the metric. For matter cylinders regular on axis, the first two solutions are the constant density Gott-Hiscock string and a cylinder with a metric Airy function. All members of this family have the Vilenkin limit to their mass per length. Some examples of Bessel shells and Bessel motion are given.

  12. Conformal Pad-Printing Electrically Conductive Composites onto Thermoplastic Hemispheres: Toward Sustainable Fabrication of 3-Cents Volumetric Electrically Small Antennas.

    PubMed

    Wu, Haoyi; Chiang, Sum Wai; Yang, Cheng; Lin, Ziyin; Liu, Jingping; Moon, Kyoung-Sik; Kang, Feiyu; Li, Bo; Wong, Ching Ping

    2015-01-01

    Electrically small antennas (ESAs) are becoming one of the key components in the compact wireless devices for telecommunications, defence, and aerospace systems, especially for the spherical one whose geometric layout is more closely approaching Chu's limit, thus yielding significant bandwidth improvements relative to the linear and planar counterparts. Yet broad applications of the volumetric ESAs are still hindered since the low cost fabrication has remained a tremendous challenge. Here we report a state-of-the-art technology to transfer electrically conductive composites (ECCs) from a planar mould to a volumetric thermoplastic substrate by using pad-printing technology without pattern distortion, benefit from the excellent properties of the ECCs as well as the printing-calibration method that we developed. The antenna samples prepared in this way meet the stringent requirement of an ESA (ka is as low as 0.32 and the antenna efficiency is as high as 57%), suggesting that volumetric electronic components i.e. the antennas can be produced in such a simple, green, and cost-effective way. This work can be of interest for the development of studies on green and high performance wireless communication devices.

  13. Conformal Pad-Printing Electrically Conductive Composites onto Thermoplastic Hemispheres: Toward Sustainable Fabrication of 3-Cents Volumetric Electrically Small Antennas

    PubMed Central

    Wu, Haoyi; Chiang, Sum Wai; Yang, Cheng; Lin, Ziyin; Liu, Jingping; Moon, Kyoung-Sik; Kang, Feiyu; Li, Bo; Wong, Ching Ping

    2015-01-01

    Electrically small antennas (ESAs) are becoming one of the key components in the compact wireless devices for telecommunications, defence, and aerospace systems, especially for the spherical one whose geometric layout is more closely approaching Chu’s limit, thus yielding significant bandwidth improvements relative to the linear and planar counterparts. Yet broad applications of the volumetric ESAs are still hindered since the low cost fabrication has remained a tremendous challenge. Here we report a state-of-the-art technology to transfer electrically conductive composites (ECCs) from a planar mould to a volumetric thermoplastic substrate by using pad-printing technology without pattern distortion, benefit from the excellent properties of the ECCs as well as the printing-calibration method that we developed. The antenna samples prepared in this way meet the stringent requirement of an ESA (ka is as low as 0.32 and the antenna efficiency is as high as 57%), suggesting that volumetric electronic components i.e. the antennas can be produced in such a simple, green, and cost-effective way. This work can be of interest for the development of studies on green and high performance wireless communication devices. PMID:26317999

  14. Combined fast multipole-QR compression technique for solving electrically small to large structures for broadband applications

    NASA Technical Reports Server (NTRS)

    Jandhyala, Vikram (Inventor); Chowdhury, Indranil (Inventor)

    2011-01-01

    An approach that efficiently solves for a desired parameter of a system or device that can include both electrically large fast multipole method (FMM) elements, and electrically small QR elements. The system or device is setup as an oct-tree structure that can include regions of both the FMM type and the QR type. An iterative solver is then used to determine a first matrix vector product for any electrically large elements, and a second matrix vector product for any electrically small elements that are included in the structure. These matrix vector products for the electrically large elements and the electrically small elements are combined, and a net delta for a combination of the matrix vector products is determined. The iteration continues until a net delta is obtained that is within predefined limits. The matrix vector products that were last obtained are used to solve for the desired parameter.

  15. Flow over an inline oscillating circular cylinder in the wake of a stationary circular cylinder

    NASA Astrophysics Data System (ADS)

    Zhang, Yang; Zhu, Keqiang

    2017-02-01

    Flow interference between an upstream stationary cylinder and an inline oscillating cylinder is studied with the lattice Boltzmann method. With a fixed Reynolds number Re = 100 and pitch ratio L/D = 4, the effects of oscillation amplitude A/D = [0.25, 1] and frequency f e/f s = [0.5, 2] are investigated. The wake response state is categorized into lock-in and non-lock-in. The lock-in zone in the bifurcation diagram of amplitude versus frequency is discontinuous. Response states of upstream and downstream wakes are similar under the conditions of small amplitude or low frequency. However, with large oscillating parameters, the two wakes are prone to be in different states as the flow field becomes irregular. Two distinct flow regimes have been identified, i.e., single-cylinder and two-cylinder shedding regimes. The presence of single-cylinder shedding regime is attributed to the low shedding frequency of the downstream cylinder at large amplitude. Hydrodynamic forces of the oscillating tandem system are discussed. The results reveal that forces on the two cylinders behave differently and that the absence of vortices in the gap flow significantly reduces the forces exerting on the tandem system.

  16. Design for a Simple and Inexpensive Cylinder-within-a-Cylinder Gradient Maker for the Undergraduate Biochemistry Laboratory

    ERIC Educational Resources Information Center

    Sims, Paul A.; O'Mealey, Gary B.; Khan, Nabeel A.; Larabee, Chelsea M.

    2011-01-01

    A design for a simple and inexpensive gradient maker is described. The gradient maker is assembled by (i) cutting the tops off two plastic bottles of differing diameters to produce two cylinders with intact bottoms; (ii) drilling a small hole toward the bottom of the smaller diameter cylinder and plugging the hole with a size 00 cork stopper; and…

  17. Internal electric fields in small water clusters [(H2O)n; n = 2-6].

    PubMed

    Sen, Saumik; Boda, Manjusha; Venkat Lata, S; Naresh Patwari, G

    2016-06-22

    The electric field experienced by a water molecule within a water cluster depends on its position relative to the rest of the water molecules. The stabilization energies and the red-shifts in the donor O-H stretching vibrations in the water clusters increase with the cluster size concomitant with the increase in the electric field experienced by the donor O-H of a particular water molecule due to the hydrogen bonding network. The red-shifts in O-H stretching frequencies show a spread of about ±100 cm(-1) against the corresponding electric fields. Deviations from linearity were marked in the region of 100-160 MV cm(-1), which can be attributed to the strain in the hydrogen bonding network, especially for structures with DDAA and DDA motifs. The linear Stark effect holds up to 200 MV cm(-1) of internal electric field for the average red-shifts in the O-H stretching frequencies, with a Stark tuning rate of 2.4 cm(-1) (MV cm(-1))(-1), suggesting the validity of the classical model in small water clusters.

  18. Relativistically corrected electric field gradients calculated with the normalized elimination of the small component formalism.

    PubMed

    Filatov, Michael; Zou, Wenli; Cremer, Dieter

    2012-08-07

    Based on the analytic derivatives formalism for the spin-free normalized elimination of the small component method, a new computational scheme for the calculation of the electric field gradient at the atomic nuclei was developed and presented. The new computational scheme was tested by the calculation of the electric field gradient at the mercury nucleus in a series of Hg-containing inorganic and organometallic compounds. The benchmark calculations demonstrate that the new formalism is capable of reproducing experimental and theoretical reference data with high accuracy. The method developed can be routinely applied to the calculation of large and very large molecules and holds considerable promise for the interpretation of the experimental data of biologically relevant compounds containing heavy elements.

  19. Technique for Solving Electrically Small to Large Structures for Broadband Applications

    NASA Technical Reports Server (NTRS)

    Jandhyala, Vikram; Chowdhury, Indranil

    2011-01-01

    Fast iterative algorithms are often used for solving Method of Moments (MoM) systems, having a large number of unknowns, to determine current distribution and other parameters. The most commonly used fast methods include the fast multipole method (FMM), the precorrected fast Fourier transform (PFFT), and low-rank QR compression methods. These methods reduce the O(N) memory and time requirements to O(N log N) by compressing the dense MoM system so as to exploit the physics of Green s Function interactions. FFT-based techniques for solving such problems are efficient for spacefilling and uniform structures, but their performance substantially degrades for non-uniformly distributed structures due to the inherent need to employ a uniform global grid. FMM or QR techniques are better suited than FFT techniques; however, neither the FMM nor the QR technique can be used at all frequencies. This method has been developed to efficiently solve for a desired parameter of a system or device that can include both electrically large FMM elements, and electrically small QR elements. The system or device is set up as an oct-tree structure that can include regions of both the FMM type and the QR type. The system is enclosed with a cube at a 0- th level, splitting the cube at the 0-th level into eight child cubes. This forms cubes at a 1st level, recursively repeating the splitting process for cubes at successive levels until a desired number of levels is created. For each cube that is thus formed, neighbor lists and interaction lists are maintained. An iterative solver is then used to determine a first matrix vector product for any electrically large elements as well as a second matrix vector product for any electrically small elements that are included in the structure. These matrix vector products for the electrically large and small elements are combined, and a net delta for a combination of the matrix vector products is determined. The iteration continues until a net delta is

  20. Proceedings of Small Power Systems Solar Electric Workshop. Volume 2: Invited papers

    NASA Technical Reports Server (NTRS)

    Ferber, R. (Editor)

    1978-01-01

    The focus of this work shop was to present the committment to the development of solar thermal power plants for a variety of applications including utility applications. Workshop activities included panel discussions, formal presentations, small group interactive discussions, question and answer periods, and informal gatherings. Discussion on topics include: (1) solar power technology options; (2) solar thermal power programs currently underway at the DOE, JPL, Electric Power Research Institute (EPRI), and Solar Energy Research Institute (SERI); (3) power options competing with solar; (4) institutional issues; (5) environmental and siting issues; (6) financial issues; (7) energy storage; (8) site requirements for experimental solar installations, and (9) utility planning.

  1. Small UAV Research and Evolution in Long Endurance Electric Powered Vehicles

    NASA Technical Reports Server (NTRS)

    Logan, Michael J.; Chu, Julio; Motter, Mark A.; Carter, Dennis L.; Ol, Michael; Zeune, Cale

    2007-01-01

    This paper describes recent research into the advancement of small, electric powered unmanned aerial vehicle (UAV) capabilities. Specifically, topics include the improvements made in battery technology, design methodologies, avionics architectures and algorithms, materials and structural concepts, propulsion system performance prediction, and others. The results of prototype vehicle designs and flight tests are discussed in the context of their usefulness in defining and validating progress in the various technology areas. Further areas of research need are also identified. These include the need for more robust operating regimes (wind, gust, etc.), and continued improvement in payload fraction vs. endurance.

  2. Cylinder To Cylinder Balancing Using Intake Valve Actuation

    SciTech Connect

    Duffy, Kevin P.; Kieser, Andrew J.; Kilkenny, Jonathan P.

    2005-01-18

    A method and apparatus for balancing a combustion phasing between a plurality of cylinders located in an engine. The method and apparatus includes a determining a combustion timing in each cylinder, establishing a baseline parameter for a desired combustion timing, and varying actuation of at least one of a plurality of intake valves, each intake valve being in fluid communication with a corresponding cylinder, such that the combustion timing in each cylinder is substantially equal to the desired combustion timing.

  3. Measurement of Electrical Conductivity into Tomato Cultivation Beds using Small Insertion Type Electrical Conductivity Sensor Designed for Agriculture

    NASA Astrophysics Data System (ADS)

    Kawashima, Kazuko; Futagawa, Masato; Ban, Yoshihiro; Asano, Yoshiyuki; Sawada, Kazuaki

    Our group has studied on-site monitoring sensor for agricultural field. An electrical conductivity (EC) sensor had been fabricated using Si integrated circuit technology. EC information of solutions shows ion concentrations dissolving in water, and can be used as the index of nutrient concentration for plants. So, it is important to measure EC in real time and on site. Because our EC sensor (5mm×5mm in size) is smaller than other commercial ones (several centimeters), it is easy to insert and achieve measurement in rock wool. In this study, our sensor measured long term EC values in tomato cultivation soil and rock wool medium. At first, we calibrated a relationship between output voltages and EC values on the sensor. The sensor was confirmed about enough EC measurement range from 8 to 969mS/m. In long period measurement, the sensor was confirmed about continuous operation for over five months, and intermittent measurement for over a year. In measurement in the cultivation soil, the sensor indicated that water was kept and diffused in the soil. In contrast, it was found that water diffused without keeping in it in rock wool medium. We confirmed our small EC sensor is useful for on-site monitoring and analysis of solution concentration distribution in several kinds of cultivation bed in real time.

  4. Induced charge electrophoresis of a conducting cylinder in a nonconducting cylindrical pore and its micromotoring application

    NASA Astrophysics Data System (ADS)

    Feng, Huicheng; Wong, Teck Neng; Che, Zhizhao

    2016-08-01

    Induced charge electrophoresis of a conducting cylinder suspended in a nonconducting cylindrical pore is theoretically analyzed and a micromotor is proposed that utilizes the cylinder rotation. The cylinder velocities are analytically obtained in the Dirichlet and the Neumann boundary conditions of the electric field on the cylindrical pore. The results show that the cylinder not only translates but also rotates when it is eccentric with respect to the cylindrical pore. The influences of a number of parameters on the cylinder velocities are characterized in detail. The cylinder trajectories show that the cylinder approaches and becomes stationary at certain positions within the cylindrical pore. The proposed micromotor is capable of working under a heavy load with a high rotational velocity when the eccentricity is large and the applied electric field is strong.

  5. Measurement of small mechanical vibrations of brain tissue exposed to extremely-low-frequency electric fields.

    PubMed

    Spiegel, R J; Ali, J S; Peoples, J F; Joines, W T

    1986-01-01

    Electromagnetic fields can interact with biological tissue both electrically and mechanically. This study investigated the mechanical interaction between brain tissue and an extremely-low-frequency (ELF) electric field by measuring the resultant vibrational amplitude. The exposure cell is a section of X-band waveguide that was modified by the addition of a center conductor to form a small TEM cell within the waveguide structure. The ELF signal is applied to the center conductor of the TEM cell. The applied ELF electric field generates an electrostrictive force on the surface of the brain tissue. This force causes the tissue to vibrate at a frequency equal to twice the frequency of the applied sinusoidal signal. An X-band signal is fed through the waveguide, scattered by the vibrating sample, and detected by a phase-sensitive receiver. Using a time-averaging spectrum analyzer, a vibration sensitivity of approximately 0.2 nmp-p can be achieved. The amplitude of the brain tissue vibrational response is constant for vibrational frequencies below 50 Hz; between 50 and 200 Hz resonant phenomena were observed; and above 200 Hz the amplitude fall-off is rapid.

  6. Measurement of small mechanical vibrations of brain tissue exposed to extremely-low-frequency electric fields

    SciTech Connect

    Spiegel, R.J.; Ali, J.S.; Peoples, J.F.; Joines, W.T.

    1986-01-01

    Electromagnetic fields can interact with biological tissue both electrically and mechanically. This study investigated the mechanical interaction between brain tissue and an extremely-low-frequency (ELF) electric field by measuring the resultant vibrational amplitude. The exposure cell is a section of X-band waveguide that was modified by the addition of a center conductor to form a small TEM cell within the waveguide structure. The ELF signal is applied to the center conductor of the TEM cell. The applied ELF electric field generates an electrostrictive force on the surface of the brain tissue. This force causes the tissue to vibrate at a frequency equal to twice the frequency of the applied sinusoidal signal. An X-band signal is fed through the waveguide, scattered by the vibrating sample, and detected by a phrase-sensitive receiver. Using a time-averaging spectrum analyzer, a vibration sensitivity of approximately 0.2 nmpp can be achieved. The amplitude of the brain tissue vibrational frequencies below 50 Hz; between 50 and 200 Hz resonant phenomena were observed; and above 200 Hz the amplitude fall-off is rapid.

  7. Efficient Radiation by Electrically Small Antennas made of Coupled Split-ring Resonators

    PubMed Central

    Peng, Liang; Chen, Peiwei; Wu, Aiting; Wang, Gaofeng

    2016-01-01

    In this paper, coupled split-ring resonators (SRRs) are used to construct the electrically small antennas. We show that through strong magnetic coupling, the coupled SRRs composite can oscillate at a wavelength much larger than its total size. Due to its magnetic dipole feature, the coupled SRRs composite allows the electromagnetic (EM) power to radiate and hence forms the electrically small antenna (ESA). Because of the high-Q resonance, the ESA could be easily matched to the driving circuit in the microwave region, through mutual induction approach. We also demonstrate that the radiation efficiency of such ESAs can be drastically improved if the current distribution on individual SRRs is similar, which is achievable by carefully designing the ESAs. From our simulations and experimental measurements, the ESAs’ radiation efficiency can reach up to 41%, with relative footprint of 0.05λ0 × 0.05λ0. Our approach would be an effective way to realize ESAs with high efficiency, which can be implemented on chip through the standard planar lithography. PMID:27630076

  8. Efficient Radiation by Electrically Small Antennas made of Coupled Split-ring Resonators

    NASA Astrophysics Data System (ADS)

    Peng, Liang; Chen, Peiwei; Wu, Aiting; Wang, Gaofeng

    2016-09-01

    In this paper, coupled split-ring resonators (SRRs) are used to construct the electrically small antennas. We show that through strong magnetic coupling, the coupled SRRs composite can oscillate at a wavelength much larger than its total size. Due to its magnetic dipole feature, the coupled SRRs composite allows the electromagnetic (EM) power to radiate and hence forms the electrically small antenna (ESA). Because of the high-Q resonance, the ESA could be easily matched to the driving circuit in the microwave region, through mutual induction approach. We also demonstrate that the radiation efficiency of such ESAs can be drastically improved if the current distribution on individual SRRs is similar, which is achievable by carefully designing the ESAs. From our simulations and experimental measurements, the ESAs’ radiation efficiency can reach up to 41%, with relative footprint of 0.05λ0 × 0.05λ0. Our approach would be an effective way to realize ESAs with high efficiency, which can be implemented on chip through the standard planar lithography.

  9. Turbine endwall single cylinder program

    NASA Technical Reports Server (NTRS)

    Langston, L. S.; Eckerle, W. A.

    1983-01-01

    Measurements of the flow field in front of a large-scale single cylinder, mounted in a wind tunnel are discussed. Static pressures on the endwall and cylinder surfaces, extensive five-hole probe pressures in front of and around the cylinder, and velocity fluctuations using a hot-wire probe where the flow is steady enough to yield meaningful results are included.

  10. Simulation of Flow Around Cylinder Actuated by DBD Plasma

    NASA Astrophysics Data System (ADS)

    Wang, Yuling; Gao, Chao; Wu, Bin; Hu, Xu

    2016-07-01

    The electric-static body force model is obtained by solving Maxwell's electromagnetic equations. Based on the electro-static model, numerical modeling of flow around a cylinder with a dielectric barrier discharge (DBD) plasma effect is also presented. The flow streamlines between the numerical simulation and the particle image velocimetry (PIV) experiment are consistent. According to the numerical simulation, DBD plasma can reduce the drag coefficient and change the vortex shedding frequencies of flow around the cylinder.

  11. Method for Making a Carbon-Carbon Cylinder Block

    NASA Technical Reports Server (NTRS)

    Ransone, Phillip O. (Inventor)

    1997-01-01

    A method for making a lightweight cylinder block composed of carbon-carbon is disclosed. The use of carbon-carbon over conventional materials. such as cast iron or aluminum, reduces the weight of the cylinder block and improves thermal efficiency of the internal combustion reciprocating engine. Due to the negligible coefficient of thermal expansion and unique strength at elevated temperatures of carbon-carbon, the piston-to-cylinder wall clearance can be small, especially when the carbon-carbon cylinder block is used in conjunction with a carbon-carbon piston. Use of the carbon-carbon cylinder block has the effect of reducing the weight of other reciprocating engine components allowing the piston to run at higher speeds and improving specific engine performance.

  12. ``Reverse'' Lock-in Regime on a Freely Oscillating Cylinder

    NASA Astrophysics Data System (ADS)

    Atsavapranee, P.; Voorhees, A. V.; Benaroya, H.; Wei, T.

    1998-11-01

    DPIV and flow visualizations were used to characterize the flow in the near wake of a freely oscillating cylinder. A rigid cylinder with a low mass ratio was fixed at one end to a leaf spring and free to oscillate, pendulum-like, at the other end in the cross stream plane. It was found that only a subset of the synchronization range follows the behavior of a ``classical'' lock-in, i.e., when the difference between the natural Strouhal frequency and the natural frequency of the cylinder is small enough, vortex shedding frequency deviates from the linear Strouhal dependence and follows instead the cylinder natural frequency. However, over a range of flow speed in which the response amplitude of the cylinder is significant, it was found that the frequency of oscillation and of vortex shedding follow instead the natural Strouhal frequency, instead of the mechanical natural frequency.

  13. Selecting Sustainability Indicators for Small to Medium Sized Urban Water Systems Using Fuzzy-ELECTRE.

    PubMed

    Chhipi-Shrestha, Gyan; Hewage, Kasun; Sadiq, Rehan

    2017-03-01

      Urban water systems (UWSs) are challenged by the sustainability perspective. Certain limitations of the sustainability of centralized UWSs and decentralized household level wastewater treatments can be overcome by managing UWSs at an intermediate scale, referred to as small to medium sized UWSs (SMUWSs). SMUWSs are different from large UWSs, mainly in terms of smaller infrastructure, data limitation, smaller service area, and institutional limitations. Moreover, sustainability assessment systems to evaluate the sustainability of an entire UWS are very limited and confined only to large UWSs. This research addressed the gap and has developed a set of 38 applied sustainability performance indicators (SPIs) by using fuzzy-Elimination and Choice Translating Reality (ELECTRE) I outranking method to assess the sustainability of SMUWSs. The developed set of SPIs can be applied to existing and new SMUWSs and also provides a flexibility to include additional SPIs in the future based on the same selection criteria.

  14. Small angle x-ray scattering and electron microscopy of nanoparticles formed in an electrical arc

    NASA Astrophysics Data System (ADS)

    Carvou, E.; Garrec, J. L. Le; Pérez, J.; Praquin, J.; Djeddi, M.; Mitchell, J. B. A.

    2013-03-01

    Small Angle X-ray Scattering has been used to characterize nanoparticles generated by electrical arcing between metallic (AgSnO2) electrodes. The particles are found to have diameters between 30 and 40 nm and display smooth surfaces suggesting that they are either in liquid form or have solidified from the liquid state. Particles collected around the electrodes were analyzed by Transmission Electron Microscopy and were seen to be much larger than those seen in the SAXS measurement, to be spherical in form and composed of silver metal with irregular tin oxide particles deposited on their surface. Mixed metal nanoparticles can have important practical applications and the use of mixed sintered electrodes may be a direct method for their production.

  15. Potential reuse of small household waste electrical and electronic equipment: Methodology and case study.

    PubMed

    Bovea, María D; Ibáñez-Forés, Valeria; Pérez-Belis, Victoria; Quemades-Beltrán, Pilar

    2016-07-01

    This study proposes a general methodology for assessing and estimating the potential reuse of small waste electrical and electronic equipment (sWEEE), focusing on devices classified as domestic appliances. Specific tests for visual inspection, function and safety have been defined for ten different types of household appliances (vacuum cleaner, iron, microwave, toaster, sandwich maker, hand blender, juicer, boiler, heater and hair dryer). After applying the tests, reuse protocols have been defined in the form of easy-to-apply checklists for each of the ten types of appliance evaluated. This methodology could be useful for reuse enterprises, since there is a lack of specific protocols, adapted to each type of appliance, to test its potential of reuse. After applying the methodology, electrical and electronic appliances (used or waste) can be segregated into three categories: the appliance works properly and can be classified as direct reuse (items can be used by a second consumer without prior repair operations), the appliance requires a later evaluation of its potential refurbishment and repair (restoration of products to working order, although with possible loss of quality) or the appliance needs to be finally discarded from the reuse process and goes directly to a recycling process. Results after applying the methodology to a sample of 87.7kg (96 units) show that 30.2% of the appliances have no potential for reuse and should be diverted for recycling, while 67.7% require a subsequent evaluation of their potential refurbishment and repair, and only 2.1% of them could be directly reused with minor cleaning operations. This study represents a first approach to the "preparation for reuse" strategy that the European Directive related to Waste Electrical and Electronic Equipment encourages to be applied. However, more research needs to be done as an extension of this study, mainly related to the identification of the feasibility of repair or refurbishment operations.

  16. Gravity flow operated small electricity generator retrofit kit to flour mill industry.

    PubMed

    Shekara, Prithivi; Kumar V, Pavan; Hosamane, Gangadharappa Gundabhakthara

    2013-10-01

    Flour milling is a grinding process to produce flour from wheat through comprehensive stages of grinding and separation. The primary energy is required to provide power used in grinding of wheat. In wheat milling, tempering is the process of adding water to wheat before milling to toughen the bran and mellow the endosperm. Gravity flow of the wheat is utilized to rotate the dampener wheel with cups to add water. Low cost gravity flow operated small electricity generator retrofit kit for dampener was designed and developed to justify low cost energy production without expensive solutions. Results of statistical analysis indicated that there was significant difference in mean values for voltage, rpm and flow rate at the 95% probability level. The resulted maximum mechanical power and measured electrical power were 5.1 W and 4.9 W respectively at wheat flow rate of 1.6 Kg/s and dampener wheel rotational velocity of 4.4 rad/s.

  17. Evaluating shock absorption behavior of small-sized systems under programmable electric field.

    PubMed

    Jagtap, Piyush; Kumar, Praveen

    2014-11-01

    A simple ball-drop impact tester is developed for studying the dynamic response of hierarchical, complex, small-sized systems and materials. The developed algorithm and set-up have provisions for applying programmable potential difference along the height of a test specimen during an impact loading; this enables us to conduct experiments on various materials and smart structures whose mechanical behavior is sensitive to electric field. The software-hardware system allows not only acquisition of dynamic force-time data at very fast sampling rate (up to 2 × 10(6) samples/s), but also application of a pre-set potential difference (up to ±10 V) across a test specimen for a duration determined by feedback from the force-time data. We illustrate the functioning of the set-up by studying the effect of electric field on the energy absorption capability of carbon nanotube foams of 5 × 5 × 1.2 mm(3) size under impact conditions.

  18. Theory of small-scale density and electric field fluctuations in the nightside Venus ionosphere

    NASA Technical Reports Server (NTRS)

    Huba, J. D.

    1992-01-01

    Recently, it has been reported that small-scale (lambda about 0.1-2 km) density irregularities occur during 100-Hz electric field bursts in the nightside ionosphere of Venus. This paper provides a detailed analysis of the lower-hybrid-drift instability as a mechanism to generate the observed irregularities. A fully electromagnetic theory is developed that is relevant to the finite beta plasma in Venus's ionosphere and includes collisional effects (e.g., electron-ion, electron-neutral, and ion-neutral collisions). The key features of the analysis that favor this instability are the following: (1) it is a flute mode and propagates orthogonal to the ambient magnetic field; (2) it is a relatively short wavelength mode and the Doppler-shifted frequency can be greater than about 100 Hz; (3) it can produce both electric field and density fluctuations, as well as magnetic field fluctuations in a finite beta plasma; and (4) it is most unstable in low-beta plasmas so that it is likely to occur in the low-density, high-magnetic-field ionospheric holes. These features are consistent with observational results.

  19. Small Internal Combustion Engine Testing for a Hybrid-Electric Remotely-Piloted Aircraft

    DTIC Science & Technology

    2011-03-01

    means of a connecting rod. The linear motion of the piston is translated into rotational motion through the connection between crankshaft and connecting...aligned in a V-shape which is well balanced and linearly compact. Six and eight cylinder engines are also commonly arranged in a linear or straight... apparatus . Power is calculated from torque and angular speed measurements by means of Equation 3. 2 3 Power is most often expressed in units of kW

  20. Small scale monitoring of a bioremediation barrier using miniature electrical resistivity tomography

    NASA Astrophysics Data System (ADS)

    Sentenac, Philippe; Hogson, Tom; Keenan, Helen; Kulessa, Bernd

    2015-04-01

    The aim of this study was to assess, in the laboratory, the efficiency of a barrier of oxygen release compound (ORC) to block and divert a diesel plume migration in a scaled aquifer model using miniature electrical resistivity tomography (ERT) as the monitoring system. Two plumes of contaminant (diesel) were injected in a soil model made of local sand and clay. The diesel plumes migration was imaged and monitored using a miniature resistivity array system that has proved to be accurate in soil resistivity variations in small-scaled models of soil. ERT results reflected the lateral spreading and diversion of the diesel plumes in the unsaturated zone. One of the contaminant plumes was partially blocked by the ORC barrier and a diversion and reorganisation of the diesel in the soil matrix was observed. The technique of time-lapse ERT imaging showed that a dense non-aqueous phase liquid (DNAPL) contaminant like diesel can be monitored through a bioremediation barrier and the technique is well suited to monitor the efficiency of the barrier. Therefore, miniature ERT as a small-scale modelling tool could complement conventional techniques, which require more expensive and intrusive site investigation prior to remediation.

  1. Electricity's future: the shift to efficiency and small-scale power

    SciTech Connect

    Flavin, C.

    1984-01-01

    Because most countries have rigid, centralized utility systems, small-scale power generation has barely caught on outside the US. In many countries a single state utility or a few large private utilities have exclusive rights to generate power, and these bureaucracies have concentrated on large power plants. But rapid advances under way in a wide range of small-scale generating technologies may soon encourage changes worldwide. Research programs are widespread, and international developments are closely followed. Improved energy efficiency and load management should also be considered as alternatives to building new power plants. In most regions of the world inefficient appliances can be replaced, houses weatherized, and industrial equipment upgraded for a fraction of the cost of building a new generating plant. Efficiency can be promoted many ways, but some of the best include utility-sponsored information and financing programs, with a return allowed on the investment, just as a new power plant would receive. Electricity prices can be adjusted to encourage less power use at peak periods, thus avoiding the need to build additional plants. Many utilities have recently adopted efficiency programs at the insistence of government regulators, but most are just token efforts. 101 references.

  2. Electrical Stimulation of Mammalian Retinal Ganglion Cells Using Dense Arrays of Small-Diameter Electrodes

    NASA Astrophysics Data System (ADS)

    Sekirnjak, Chris; Hottowy, Pawel; Sher, Alexander; Dabrowski, Wladyslaw; Litke, Alan M.; Chichilnisky, E. J.

    Current epiretinal implants contain a small number of electrodes with diameters of a few hundred microns. Smaller electrodes are desirable to increase the spatial resolution of artificial sight. To lay the foundation for the next generation of retinal prostheses, we assessed the stimulation efficacy of micro-fabricated arrays of 61 platinum disk electrodes with diameters 8-12 μm, spaced 60 μm apart. Isolated pieces of rat, guinea pig, and monkey retina were placed on the multi-electrode array ganglion cell side down and stimulated through individual electrodes with biphasic, charge-balanced current pulses. Spike responses from retinal ganglion cells were recorded either from the same or a neighboring electrode. Most pulses evoked only 1-2 spikes with short latencies (0.3-10 ms), and rarely was more than one recorded ganglion cell stimulated. Threshold charge densities for eliciting spikes in ganglion cells were typically below 0.15 mC/cm2 for pulse durations between 50 and 200 μs, corresponding to charge thresholds of ˜ 100 pC. Stimulation remained effective after several hours and at frequencies up to 100 Hz. Application of cadmium chloride did not abolish evoked spikes, implying direct activation. Thus, electrical stimulation of mammalian retina with small-diameter electrodes is achievable, providing high temporal and spatial precision with low charge densities.

  3. Neural network control of a parallel hybrid-electric propulsion system for a small unmanned aerial vehicle

    NASA Astrophysics Data System (ADS)

    Harmon, Frederick G.

    2005-11-01

    Parallel hybrid-electric propulsion systems would be beneficial for small unmanned aerial vehicles (UAVs) used for military, homeland security, and disaster-monitoring missions. The benefits, due to the hybrid and electric-only modes, include increased time-on-station and greater range as compared to electric-powered UAVs and stealth modes not available with gasoline-powered UAVs. This dissertation contributes to the research fields of small unmanned aerial vehicles, hybrid-electric propulsion system control, and intelligent control. A conceptual design of a small UAV with a parallel hybrid-electric propulsion system is provided. The UAV is intended for intelligence, surveillance, and reconnaissance (ISR) missions. A conceptual design reveals the trade-offs that must be considered to take advantage of the hybrid-electric propulsion system. The resulting hybrid-electric propulsion system is a two-point design that includes an engine primarily sized for cruise speed and an electric motor and battery pack that are primarily sized for a slower endurance speed. The electric motor provides additional power for take-off, climbing, and acceleration and also serves as a generator during charge-sustaining operation or regeneration. The intelligent control of the hybrid-electric propulsion system is based on an instantaneous optimization algorithm that generates a hyper-plane from the nonlinear efficiency maps for the internal combustion engine, electric motor, and lithium-ion battery pack. The hyper-plane incorporates charge-depletion and charge-sustaining strategies. The optimization algorithm is flexible and allows the operator/user to assign relative importance between the use of gasoline, electricity, and recharging depending on the intended mission. A MATLAB/Simulink model was developed to test the control algorithms. The Cerebellar Model Arithmetic Computer (CMAC) associative memory neural network is applied to the control of the UAVs parallel hybrid-electric

  4. Self-assembly of Janus cylinders into hierarchical superstructures.

    PubMed

    Walther, Andreas; Drechsler, Markus; Rosenfeldt, Sabine; Harnau, Ludger; Ballauff, Matthias; Abetz, Volker; Müller, Axel H E

    2009-04-08

    We present in-depth studies of the size tunability and the self-assembly behavior of Janus cylinders possessing a phase segregation into two hemicylinders. The cylinders are prepared by cross-linking the lamella-cylinder morphology of a polystyrene-block-polybutadiene-block-poly(methyl methacrylate) block terpolymer. The length of the Janus cylinders can be adjusted by both the amplitude and the duration of a sonication treatment from the micro- to the nanometer length. The corona segregation into a biphasic particle is evidenced by selective staining of the PS domains with RuO(4) and subsequent imaging. The self-assembly behavior of these facial amphiphiles on different length scales is investigated combining dynamic light scattering (DLS), small-angle neutron scattering (SANS), and imaging procedures. Cryogenic transmission electron microscopy images of the Janus cylinders in THF, which is a good solvent for both blocks, exhibit unimolecularly dissolved Janus cylinders with a core-corona structure. These results are corroborated by SANS measurements. Supramolecular aggregation takes place in acetone, which is a nonsolvent for polystyrene, leading to the observation of fiber-like aggregates. The length of these fibers depends on the concentration of the solution. A critical aggregation concentration is found, under which unimolecularly dissolved Janus cylinders exist. The fibers are composed of 2-4 Janus cylinders, shielding the inner insoluble polystyrene hemicylinder against the solvent. Herein, the SANS data reveal a core-shell structure of the aggregates. Upon deposition of the Janus cylinders from more concentrated solution, a second type of superstructure is formed on a significantly larger length scale. The Janus cylinders form fibrillar networks, in which the pore size depends on the concentration and deposition time of the sample.

  5. Rate of flow of digesta and electrical activity of the small intestine in dogs and sheep.

    PubMed

    Bueno, L; Fioramonti, J; Ruckebusch, Y

    1975-07-01

    1. Spiking activity of the small intestine in the conscious dog and sheep was recorded continuously from electrodes chronically implanted on the jejunum and summed at intervals of 20 sec. The activity was related to the transit time and flow rate of intestinal contents as estimated by phenol red and by dilution of continuous marker infusions respectively. Also in some sheep the flow of digesta was measured directly from a cannula in the proximal part of the jejunum, and also by use of an electromagnetic flow meter. 2. In the fasted dog and in sheep on a normal diet the intestinal activity was characterized by a migrating myo-electric complex comprising an irregular phase followed by a regular phase. These migrating myo-electric complexes occurred regularly after a period of inactivity at a frequency of 15-20/24 hr. In dogs after feeding, a continuous spiking activity appeared and persisted for periods of 7-8 hr. This was associated with much higher rates of flow and shorter transit times than were observed during fasting. In sheep, continuous spiking activity could be induced by intravenous injection of 5-hydroxytryptophan and this, similarly, was accompanied by a more rapid flow and a shorter transit time than recorded during the control period. 3. In both species the longest transit time occurred when a phenol red bolus was injected during the period of electrical inactivity. Relatively short transit times were observed when the bolus was administered just before the period of regular spiking activity. 4. When relaxation of the bowel was induced by intraperitoneal injection of hypertonic saline there was no spiking activity and the transit time for the infused solution was greatly lengthened, especially in the sheep. A noticeable flow of digestive contents persisted in the dog. 5. In the sheep the intestinal contents flowed intermittently during periods of 10-15 min and at the same frequency as the migrating myo-electric complex. Two thirds of this flow took

  6. Modeling of small scale radio-frequency inductive discharges for electric propulsion applications

    NASA Astrophysics Data System (ADS)

    Mistoco, Valerie F. M.

    This work is motivated by the increasing interest in small-scale radio-frequency ion thrusters for micro- and nanosatellite applications, in particular for stationkeeping. This specific type of thruster relies on an inductive discharge to produce positive ions that are accelerated by an external electric field in order to produce thrust. Analyzing the particle dynamics within the discharge vessel is critical for determining the performance of these thrusters, particularly as scaling down the size and thrust level of ion thrusters remains a major challenge. Until now the application of this type of propulsion system has been limited to large satellites and space platforms. The approach taken in this work was, first, to perform a simple analysis of the inductive discharge using a transformer model. However, the dimensions of the thruster and the pressure ranges at which it operates called for a different approach than those used in larger thrusters and reactors as the collisional domain and non-locality effects differ significantly. After estimating the non-locality effects by calculating the non-locality parameter, a kinetic description of the discharge was developed. From the input power, mass flow rate, and the properties of the gas used in the discharge, the density numbers, temperatures of the particles, and thrust are calculated. Simulation values are compared with experimental values obtained with the Miniature Radio-frequency Ion Thruster being developed at The Pennsylvania State University. The approach employed to model this small scale inductive discharge can be summarized as follows. First, conditions of operation and the various plasma parameters of the discharge were derived. Then, a one-dimensional kinetic model of an inductive discharge, using a Maxwellian electron distribution, was built. Results from this model were validated on data available in the literature. Finally, from the beam current derived from the 1-D model, using a two-grid ion optics

  7. Natural convection heat transfer from horizontal concentric and eccentric cylinder systems cooling in the ambient air and determination of inner cylinder location

    NASA Astrophysics Data System (ADS)

    Atayılmaz, Ş. Özgür; Demir, Hakan; Sevindir, Mustafa Kemal; Ağra, Özden; Teke, İsmail; Dalkılıç, Ahmet Selim

    2017-03-01

    Heat transfer characteristics of horizontal copper concentric cylinders in the case of natural convection was investigated numerically and experimentally. While the inner cylinder had an electric heater to keep it at a constant temperature, annulus was filled with water. There were two different test sections as bare and concentric cylinder systems located in different ambient temperatures in a conditioned room for the comparison of the results. Comparison of average Nusselt numbers for the air side of the concentric cylinder system and the effective thermal conductivity of the annulus were calculated with both experimental data, numerical results and a well-known correlation. Annulus and the air side isotherms and streamlines are shown for RaL = 9 × 105-5 × 106 and Ra = 2 × 105-7 × 105 respectively. Additionally, a numerical study was conducted by forming eccentric cylinder systems to determine the optimum location of inner cylinder to maximize the heat transfer rate. Comparison of heat transfer rates from bare and concentric horizontal cylinders were done under steady state conditions. Heat transfer enhancement, the effect of the decrease in condensing temperature of the inner cylinder surface on COP of an ideal Carnot refrigeration cycle and rise in COP were determined in the study. Also the optimum location of inner cylinder to maximize the heat transfer rate was determined as at the bottom quadrant of outer cylinder.

  8. Low cost venom extractor based on Arduino(®) board for electrical venom extraction from arthropods and other small animals.

    PubMed

    Besson, Thomas; Debayle, Delphine; Diochot, Sylvie; Salinas, Miguel; Lingueglia, Eric

    2016-08-01

    Extracting venom from small species is usually challenging. We describe here an affordable and versatile electrical venom extractor based on the Arduino(®) Mega 2560 Board, which is designed to extract venom from arthropods and other small animals. The device includes fine tuning of stimulation time and voltage. It was used to collect venom without apparent deleterious effects, and characterized for the first time the venom of Zoropsis spinimana, a common spider in French Mediterranean regions.

  9. Identification of leachate from livestock mortality burial using electrical resistivity and small-loop EM survey: case history

    NASA Astrophysics Data System (ADS)

    Song, Sung-Ho; Cho, In-Ky; Choi, Kwang-Jun

    2015-01-01

    Leachate from livestock mortality burial is harmful to the soil and groundwater environment and adequate assessment approaches are necessary to manage burial sites. Among the methods used to detect leachate, geophysical surveys, including electrical resistivity and electromagnetic (EM) techniques, are used in many engineering approaches to environmental problems, such as identifying contaminant plumes and evaluating hydrogeological conditions. Electrical resistivity, with a small-loop EM survey, was used in this study as a reconnaissance technique to identify the burial shape and distribution of leachate from livestock mortality burial in five small separate zones. We conducted a multi-frequency small-loop EM survey using lattice nets and acquired apparent conductivity values along several parallel and perpendicular lines over a burial site. We also compared geophysical results to the geochemical analysis of samples from both a leachate collection well and a downstream observation well within the study area. Depth slices of apparent conductivities at each frequency (obtained from the small-loop EM survey data) clearly identified the subsurface structure of the burial shape and the extent of leachate transport. Low-resistivity zones, identified from two-dimensional (2D) electrical resistivity imaging results, were matched to the five burial zones (within a depth of 5 m), as well as high electrical conductivity of the leachate obtained from leachate collection wells, and depth slices of the apparent conductivity distribution obtained from the small-loop EM survey. A three-dimensional (3D) inversion of resistivity data provided a detailed 3D structure of the overall burial site and leachate pathways. Moreover, these zones were widely spread over the burial site, indicating that leachate potentially extended through damaged regions of the composite liner to a depth of 10 m along the downstream groundwater flow. Both the small-loop EM method and the electrical

  10. Radiative corrections to the polarizability tensor of an electrically small anisotropic dielectric particle.

    PubMed

    Albaladejo, S; Gómez-Medina, R; Froufe-Pérez, L S; Marinchio, H; Carminati, R; Torrado, J F; Armelles, G; García-Martín, A; Sáenz, J J

    2010-02-15

    Radiative corrections to the polarizability tensor of isotropic particles are fundamental to understand the energy balance between absorption and scattering processes. Equivalent radiative corrections for anisotropic particles are not well known. Assuming that the polarization within the particle is uniform, we derived a closed-form expression for the polarizability tensor which includes radiative corrections. In the absence of absorption, this expression of the polarizability tensor is consistent with the optical theorem. An analogous result for infinitely long cylinders was also derived. Magneto optical Kerr effects in non-absorbing nanoparticles with magneto-optical activity arise as a consequence of radiative corrections to the electrostatic polarizability tensor.

  11. 15. CYLINDER DETAILS; DETAILS OF STEEL FOR CYLINDERS NO. 50 ...

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

    15. CYLINDER DETAILS; DETAILS OF STEEL FOR CYLINDERS NO. 50 (PIER 5) AND NO. 66 (PIER 6), DWG. 83, CH BY AF, ECL, APPROVED BY O.F. LACKEY, MAY 18, 1908 - Baltimore Inner Harbor, Pier 5, South of Pratt Street between Market Place & Concord Street, Baltimore, Independent City, MD

  12. Effects of forskolin on electrical behaviour of myenteric neurones in guinea-pig small intestine.

    PubMed Central

    Nemeth, P R; Palmer, J M; Wood, J D; Zafirov, D H

    1986-01-01

    The actions of forskolin on electrical behaviour of myenteric neurones were investigated with intracellular recording methods in guinea-pig small intestine. The actions of forskolin were: membrane depolarization, increased input resistance, suppression of post-spike hyperpolarizing potentials and repetitive spike discharge. These effects occurred always in AH/Type 2 myenteric neurones and never in the cells classified as S/Type 1. Reversal potentials for the depolarizing effects were near the estimated potassium equilibrium potential. Analyses based on the 'constant field equation' indicated that the permeability ratios of K+ to other permeant ionic species were reduced by forskolin. Pretreatment of the neurones with a phosphodiesterase inhibitor potentiated the effects of forskolin. The results suggest that activation of adenylate cyclase by forskolin and subsequent elevation of intraneuronal adenosine 3',5'-phosphate (cyclic AMP) mimic slow synaptic excitation in AH/Type 2 myenteric neurones. They support the possibility that cyclic AMP functions as a second messenger in signal transduction which appears to involve closure of calcium-dependent K+ channels and other membrane changes that lead to depolarization and a dramatic increase in the excitability of the neurones. PMID:2432235

  13. Small Solar Electric Propulsion Spacecraft Concept for Near Earth Object and Inner Solar System Missions

    NASA Technical Reports Server (NTRS)

    Lang, Jared J.; Randolph, Thomas M.; McElrath, Timothy P.; Baker, John D.; Strange, Nathan J.; Landau, Damon; Wallace, Mark S.; Snyder, J. Steve; Piacentine, Jamie S.; Malone, Shane; Bury, Kristen M.; Tracy, William H.

    2011-01-01

    Near Earth Objects (NEOs) and other primitive bodies are exciting targets for exploration. Not only do they provide clues to the early formation of the universe, but they also are potential resources for manned exploration as well as provide information about potential Earth hazards. As a step toward exploration outside Earth's sphere of influence, NASA is considering manned exploration to Near Earth Asteroids (NEAs), however hazard characterization of a target is important before embarking on such an undertaking. A small Solar Electric Propulsion (SEP) spacecraft would be ideally suited for this type of mission due to the high delta-V requirements, variety of potential targets and locations, and the solar energy available in the inner solar system.Spacecraft and mission trades have been performed to develop a robust spacecraft design that utilizes low cost, off-the-shelf components that could accommodate a suite of different scientific payloads for NEO characterization. Mission concepts such as multiple spacecraft each rendezvousing with different NEOs, single spacecraft rendezvousing with separate NEOs, NEO landers, as well as other inner solar system applications (Mars telecom orbiter) have been evaluated. Secondary launch opportunities using the Expendable Secondary Payload Adapter (ESPA) Grande launch adapter with unconstrained launch dates have also been examined.

  14. Development of small centrifugal pumps for an electric propellant pump system

    NASA Astrophysics Data System (ADS)

    Johnsson, Göran; Bigert, Mikael

    Small centrifugal pumps with low specific speeds have been designed, manufactured and performance tested at Volvo Flygmotor AB under a contract from the European Space Agency (ESA) over the period mid-1985 to mid-1988. The development of the pumps is a part of the work carried out to develop an Electric Propellant Pump System (EPPS) for the storable propellant monomethyl hydrazine (MMH) and nitrogen tetraoxide (NTO). Supporting technology development has been funded by the Swedish Delegation for Space Activities (DFR) and Swedish Space Corporation (SSC) together with Volvo Flygmotor. The main advantages of a typical EPPS communication satellite application are weight and volume reduction of the propellant system compared with a pressure-fed system. Active engine mixture ratio control and improved propellant utilization are also possible. Refuelling in space is another potential application where EPPS can be used. The development work was focused on communication satellite apogee propulsion and used the MBB 3 kN engine as reference. This paper presents the pump design and analyses and the results from the test campaigns of three different pump configurations, carried out with water as test liquid. The head rise, efficiency and suction performance together with other characteristics are also given. The planned next development step is to demonstrate pump performance in the propellants and primarily in NTO. The step is funded by (DFR)/(SSC) together with Volvo Flygmotor.

  15. Electricity

    SciTech Connect

    Sims, B.

    1983-01-01

    Historical aspects of electricity are reviewed with individual articles on hydroelectric dams, coal-burning power plants, nuclear power plants, electricity distribution, and the energy future. A glossary is included. (PSB)

  16. Sistemas Eolicos Pequenos para Generacion de Electridad (Spanish version of Small Wind Electric Systems: A U.S. Consumer's Guide)

    SciTech Connect

    Not Available

    2005-07-01

    This Spanish version of the popular Small Wind Electric Systems: A U.S. Consumer's Guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and economics. Topics include how to make a home more energy efficient, how to choose the correct turbine size, the parts of a wind electric system, how to determine whether enough wind resource exists, how to choose the best site for a turbine, how to connect a system to the utility grid, and whether it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a list of contacts for more information.

  17. Quantum walk on a cylinder

    NASA Astrophysics Data System (ADS)

    Bru, Luis A.; de Valcárcel, Germán J.; Di Molfetta, Giuseppe; Pérez, Armando; Roldán, Eugenio; Silva, Fernando

    2016-09-01

    We consider the two-dimensional alternate quantum walk on a cylinder. We concentrate on the study of the motion along the open dimension, in the spirit of looking at the closed coordinate as a small or "hidden" extra dimension. If one starts from localized initial conditions on the lattice, the dynamics of the quantum walk that is obtained after tracing out the small dimension shows the contribution of several components which can be understood from the study of the dispersion relations for this problem. In fact, these components originate from the contribution of the possible values of the quasimomentum in the closed dimension. In the continuous space-time limit, the different components manifest as a set of Dirac equations, with each quasimomentum providing the value of the corresponding mass. We briefly discuss the possible link of these ideas to the simulation of high-energy physical theories that include extra dimensions. Finally, entanglement between the coin and spatial degrees of freedom is studied, showing that the entanglement entropy clearly overcomes the value reached with only one spatial dimension.

  18. 49 CFR 178.55 - Specification 4B240ET welded or brazed cylinders.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... cylinder made from electric resistance welded tubing. The maximum water capacity of this cylinder is 12... is, under no condition, to be less than two times the minimum wall thickness of the cylindrical shell... by the lap brazing method and must overlap not less than four times the wall thickness....

  19. Piston-cylinder apparatus for high-pressure impedance spectroscopy

    NASA Astrophysics Data System (ADS)

    Hinrichs, R.; da Jornada, J. A. H.

    1997-01-01

    A simple piston-cylinder apparatus was developed for impedance spectroscopy at pressures up to 3 GPa and temperatures up to 500 °C. The apparatus is of the compound cylinder type, with the innermost cylinder made of a commercially available low-cost alumina-based ceramic, with pistons of hard metal that allow electric connections. Cell electrical resistance was higher than 1 MΩ at T<300 °C and higher than 100 kΩ at 400 °C. The inductivity in the wires and pistons was about 2 μH. The sample was enclosed in a h-BN capsule, which insured a good hydrostaticity without disturbing the measurement. The equipment proved to be very useful in determining the activation volume of the conduction process in several ionic conductors.

  20. Development of Electrothermal Pulsed Plasma Thrusters for Osaka-Institute-of-Technology Electric-Rocket-Engine onboard Small Space Ship

    NASA Astrophysics Data System (ADS)

    Ishii, Yushuke; Yamamoto, Tsuyoshi; Yamada, Minetsugu; Tahara, Hirokazu

    2008-12-01

    The Project of Osaka-Institute-of-Technology Electric-Rocket-Engine onboard Small Space Ship (PROITERES) was started at Osaka Institute of Technology. In PROITERES, a 10-kg small satellite with electrothermal pulsed plasma thrusters (PPTs), named JOSHO, will be launched in 2010. The main mission is powered flight of small satellite by electric thruster itself. Electrothermal PPTs were studied with both experiments and numerical simulations. An electrothermal PPT with a side-fed propellant feeding mechanism achieved a total impulse of 3.6 Ns with a repetitive 10000-shot operation. An unsteady numerical simulation showed the existence of considerable amount of ablation delaying to the discharge. However, it was also shown that this phenomenon should not be regarded as the ``late time ablation'' for electrothermal PPTs.

  1. Development of Electrothermal Pulsed Plasma Thrusters for Osaka-Institute-of-Technology Electric-Rocket-Engine onboard Small Space Ship

    SciTech Connect

    Ishii, Yushuke; Yamamoto, Tsuyoshi; Yamada, Minetsugu; Tahara, Hirokazu

    2008-12-31

    The Project of Osaka-Institute-of-Technology Electric-Rocket-Engine onboard Small Space Ship (PROITERES) was started at Osaka Institute of Technology. In PROITERES, a 10-kg small satellite with electrothermal pulsed plasma thrusters (PPTs), named JOSHO, will be launched in 2010. The main mission is powered flight of small satellite by electric thruster itself. Electrothermal PPTs were studied with both experiments and numerical simulations. An electrothermal PPT with a side-fed propellant feeding mechanism achieved a total impulse of 3.6 Ns with a repetitive 10000-shot operation. An unsteady numerical simulation showed the existence of considerable amount of ablation delaying to the discharge. However, it was also shown that this phenomenon should not be regarded as the 'late time ablation' for electrothermal PPTs.

  2. Locomotion gaits of a rotating cylinder pair

    NASA Astrophysics Data System (ADS)

    van Rees, Wim M.; Novati, Guido; Koumoutsakos, Petros; Mahadevan, L.

    2015-11-01

    Using 2D numerical simulations of the Navier-Stokes equations, we demonstrate that a simple pair of rotating cylinders can display a range of locomotion patterns of biological and engineering interest. Steadily counter-rotating the cylinders causes the pair to move akin to a vortex dipole for low rotation rates, but as the rotational velocity is increased the direction of motion reverses. Unsteady rotations lead to different locomotion gaits that resemble jellyfish (for in-phase rotations) and undulating swimmers (for out-of-phase rotations). The small number of parameters for this simple system allows us to systematically map the phase space of these gaits, and allows us to understand the underlying physical mechanisms using a minimal model with implications for biological locomotion and engineered analogs.

  3. Anomalous magnetoresistance in magnetized topological insulator cylinders

    SciTech Connect

    Siu, Zhuo Bin; Jalil, Mansoor B. A.

    2015-05-07

    The close coupling between the spin and momentum degrees of freedom in topological insulators (TIs) presents the opportunity for the control of one to manipulate the other. The momentum can, for example, be confined on a curved surface and the spin influenced by applying a magnetic field. In this work, we study the surface states of a cylindrical TI magnetized in the x direction perpendicular to the cylindrical axis lying along the z direction. We show that a large magnetization leads to an upwards bending of the energy bands at small |k{sub z}|. The bending leads to an anomalous magnetoresistance where the transmission between two cylinders magnetized in opposite directions is higher than when the cylinders are magnetized at intermediate angles with respect to each other.

  4. Strain Localization in an Oscillating Maxwell Viscoelastic Cylinder.

    PubMed

    Massouros, Panagiotis G; Bayly, Philip V; Genin, Guy M

    2014-01-15

    The transient rotation responses of simple, axisymmetric, viscoelastic structures are of interest for interpretation of experiments designed to characterize materials and closed structures such as the brain using magnetic resonance techniques. Here, we studied the response of a Maxwell viscoelastic cylinder to small, sinusoidal displacement of its outer boundary. The transient strain field can be calculated in closed form using any of several conventional approaches. The solution is surprising: the strain field develops a singularity that appears when the wavefront leaves the center of the cylinder, and persists as the wavefront reflects to the outer boundary and back to the center of the cylinder. The singularity is alternately annihilated and reinitiated upon subsequent departures of the wavefront from the center of the cylinder until it disappears in the limit of steady state oscillations. We present the solution for this strain field, characterize the nature of this singularity, and discuss its potential role in the mechanical response and evolved morphology of the brain.

  5. On the flow in an annulus surrounding a whirling cylinder

    NASA Technical Reports Server (NTRS)

    Brennen, C.

    1976-01-01

    When fluid in an annulus between two cylinders is set in motion by whirling movements of one or both of the cylinders, dynamic forces are imposed by the fluid on the cylinders. Knowledge of these forces is frequently important, indeed often critical, to the engineer designing rotor systems or journal bearings. Quite general solutions of the Navier-Stokes equations are presented for this problem and are limited only by restrictions on the amplitude of the whirl motion. From these solutions, the forces are derived under a wide variety of circumstances, including large and small annular widths, high and low Reynolds numbers, and the presence and absence of a mean flow created by additional net rotation of one or both of the cylinders.

  6. Microwave heating and joining of ceramic cylinders: A mathematical model

    NASA Technical Reports Server (NTRS)

    Booty, Michael R.; Kriegsmann, Gregory A.

    1994-01-01

    A thin cylindrical ceramic sample is placed in a single mode microwave applicator in such a way that the electric field strength is allowed to vary along its axis. The sample can either be a single rod or two rods butted together. We present a simple mathematical model which describes the microwave heating process. It is built on the assumption that the Biot number of the material is small, and that the electric field is known and uniform throughout the cylinder's cross-section. The model takes the form of a nonlinear parabolic equation of reaction-diffusion type, with a spatially varying reaction term that corresponds to the spatial variation of the electromagnetic field strength in the waveguide. The equation is analyzed and a solution is found which develops a hot spot near the center of the cylindrical sample and which then propagates outwards until it stabilizes. The propagation and stabilization phenomenon concentrates the microwave energy in a localized region about the center where elevated temperatures may be desirable.

  7. Electricity's Future: The Shift to Efficiency and Small-Scale Power. Worldwatch Paper 61.

    ERIC Educational Resources Information Center

    Flavin, Christopher

    Electricity, which has largely supplanted oil as the most controversial energy issue of the 1980s, is at the center of some of the world's bitterest economic and environmental controversies. Soaring costs, high interest rates, and environmental damage caused by large power plants have wreaked havoc on the once booming electricity industry.…

  8. Optimization of Hybrid-Electric Propulsion Systems for Small Remotely-Piloted Aircraft

    DTIC Science & Technology

    2011-03-24

    86  Page viii List of Figures Page Figure 1: Series Hybrid-Electric Configuration [6...complexity and power system design. In general, H-EPS are either configured in a series or parallel configuration. 2.1. Configurations In a series ...optimum torque and speed range; therefore decreasing fuel consumption Figure 1: Series Hybrid-Electric Configuration [6] 6 and increasing efficiency

  9. Effects of interference among three equidistantly arranged cylinders in a uniform flow

    NASA Astrophysics Data System (ADS)

    Tatsuno, Masakazu; Amamoto, Hajime; Ishi-i, Koji

    1998-05-01

    The effects of flow interference among three identical circular cylinders, which were arranged in an equidistant triangular cluster with their axes perpendicular to the uniform flow, were studied at various incidence angles to the uniform flow and at different spacing ratios. The static pressures around the circumference of each cylinder were measured individually and the drag and lift coefficients of each cylinder were determined at Reynolds number of 6.2×10 4 based on the diameter of a single cylinder. The effects of flow interference among the three cylinders are severe when the spacing ratios are small. When two cylinders arranged side by side are upstream of or behind the third one, the flow patterns are not symmetrical with respect to the uniform flow direction and the drag or lift coefficients of the two cylinders in the side-by-side arrangement are not always equal to each other at small spacing ratios. The inclination angles to the uniform flow strongly influence the drag and lift coefficients, the direction of force exerted on each cylinder and the flow patterns around the cylinders. The effects of interference among three cylinders become weak as the spacing ratios are increased.

  10. Current collection by a long conducting cylinder in a flowing magnetized plasma

    NASA Technical Reports Server (NTRS)

    Singh, Nagendra; Vashi, Bharat I.

    1990-01-01

    The numerical techniques, the definitions, and the normalizations used in the simulations of plasma flow past a long conducting cylinder with a magnetic field along the cylinder axis are described. The effect of cross-field plasma transport on the current collection without any contribution to the current from the field-aligned motion of the plasma particles is highlighted. The electric fields in the structure create a two-cell circulation of the electrons near the cylinder. The cell in the wake region has negative potentials. A fan-shaped circulation cell forms around the cylinder and in this cell the potential is generally positive. The geometry and the size of this positive cell affect the current collection. The potential structure around the cylinder is examined, along with its effect on the current collection and its oscillatory behavior. The variation of the time-average current as a function of the relative motion between the plasma and the cylinder is also investigated.

  11. Anomalous n-type electrical behaviour of Pd-contacted CNTFET fabricated on small-diameter nanotube

    NASA Astrophysics Data System (ADS)

    Jejurikar, S.; Casterman, D.; Pillai, P. B.; Petrenko, O.; De Souza, M. M.; Tahraoui, A.; Durkan, C.; Milne, W. I.

    2010-05-01

    A Pd-contacted dopant-free CNTFET with small-diameter (0.57 nm) carbon nanotube showing an anomalous n-type electrical characteristic is reported for the first time. This observed behaviour is attributed to a carbon nanotube work function higher than (or close to) palladium as well as a large hole-to-electron effective mass ratio of ~ 2.5 predicted by hybridization in small-diameter nanotubes. A variation of the conduction type with temperature is also observed and is attributed to an increase of the palladium work function and decrease of the CNT work function with increasing temperature.

  12. Anomalous n-type electrical behaviour of Pd-contacted CNTFET fabricated on small-diameter nanotube.

    PubMed

    Jejurikar, S; Casterman, D; Pillai, P B; Petrenko, O; De Souza, M M; Tahraoui, A; Durkan, C; Milne, W I

    2010-05-28

    A Pd-contacted dopant-free CNTFET with small-diameter (0.57 nm) carbon nanotube showing an anomalous n-type electrical characteristic is reported for the first time. This observed behaviour is attributed to a carbon nanotube work function higher than (or close to) palladium as well as a large hole-to-electron effective mass ratio of approximately 2.5 predicted by hybridization in small-diameter nanotubes. A variation of the conduction type with temperature is also observed and is attributed to an increase of the palladium work function and decrease of the CNT work function with increasing temperature.

  13. Integration, Testing, and Validation of a Small Hybrid-Electric Remotely-Piloted Aircraft

    DTIC Science & Technology

    2012-03-22

    Parallel hybrid system configuration [34] 15 Finally, the split power configuration uses planetary gears to keep the electric motor in- line with...the use of a planetary gear instead of a clutch. For example, the Toyota Prius, which entered the US market in 2001 and topped 1,000,000 sales in...Boulder is also working on an HE-RPA utilizing planetary gearing [39]. Thus far, they have tested the planetary gearing system using two electric motors

  14. Axial cylinder internal combustion engine

    SciTech Connect

    Gonzalez, C.

    1992-03-10

    This patent describes improvement in a barrel type internal combustion engine including an engine block having axial-positioned cylinders with reciprocating pistons arranged in a circular pattern: a drive shaft concentrically positioned within the cylinder block having an offset portion extending outside the cylinder block; a wobble spider rotatably journaled to the offset portion; connecting rods for each cylinder connecting each piston to the wobble spider. The improvement comprising: a first sleeve bearing means supporting the drive shaft in the engine block in a cantilevered manner for radial loads; a second sleeve bearing means rotatably supporting the wobble spider on the offset portion of the drive shaft for radial loads; a first roller bearing means positioned between the offset portion of the drive shaft and the wobble spider carrying thrust loadings only; a second roller bearing means carrying thrust loads only reacting to the first roller bearing located on the opposite end of the driveshaft between the shaft and the engine block.

  15. Regimes of flow induced vibration for tandem, tethered cylinders

    NASA Astrophysics Data System (ADS)

    Nave, Gary; Stremler, Mark

    2015-11-01

    In the wake of a bluff body, there are a number of dynamic response regimes that exist for a trailing bluff body depending on spacing, structural restoring forces, and the mass-damping parameter m* ζ . For tandem cylinders with low values of m* ζ , two such regimes of motion are Gap Flow Switching and Wake Induced Vibration. In this study, we consider the dynamics of a single degree-of-freedom rigid cylinder in the wake of another in these regimes for a variety of center-to-center cylinder spacings (3-5 diameters) and Reynolds numbers (4,000-11,000). The system consists of a trailing cylinder constrained to a circular arc around a fixed leading cylinder, which, for small angle displacements, bears a close resemblance to the transversely oscillating cylinders found more commonly in existing literature. From experiments on this system, we compare and contrast the dynamic response within these two regimes. Our results show sustained oscillations in the absence of a structural restoring force in all cases, providing experimental support for the wake stiffness assumption, which is based on the mean lift toward the center line of flow.

  16. Turbine endwall single cylinder program

    NASA Technical Reports Server (NTRS)

    Langston, L. S.

    1982-01-01

    Detailed measurement of the flow field in front of a large-scale single cylinder, mounted in a wind tunnel is discussed. A better understanding of the three dimensional separation occuring in front of the cylinder on the endwall, and of the vortex system that is formed is sought. A data base with which to check analytical and numerical computer models of three dimensional flows is also anticipated.

  17. Scattering of light by polydisperse, randomly oriented, finite circular cylinders.

    PubMed

    Mishchenko, M I; Travis, L D; Macke, A

    1996-08-20

    We use the T-matrix method, as described by Mishchenko [Appl. Opt. 32, 4652 (1993)], to compute rigorously light scattering by finite circular cylinders in random orientation. First we discuss numerical aspects of T -matrix computations specific for finite cylinders and present results of benchmark computations for a simple cylinder model. Then we report results of extensive computations for polydisperse, randomly oriented cylinders with a refractive index of 1.53 + 0.008i, diameter-to-length ratios of 1/2, 1/1.4, 1, 1.4, and 2, and effective size parameters ranging from 0 to 25. These computations parallel our recent study of light scattering by polydisperse, randomly oriented spheroids and are used to compare scattering properties of the two classes of simple convex particles. Despite the significant difference in shape between the two particle types (entirely smooth surface for spheroids and sharp rectangular edges for cylinders), the comparison shows rather small differences in the integral photometric characteristics (total optical cross sections, single-scattering albedo, and asymmetry parameter of the phase function) and the phase function. The general patterns of the other elements of the scattering matrix for cylinders and aspect-ratio-equivalent spheroids are also qualitatively similar, although noticeable quantitative differences can be found in some particular cases. In general, cylinders demonstrate much less shape dependence of the elements of the scattering matrix than do spheroids. Our computations show that, like spheroids and bispheres, cylinders with surface-equivalent radii smaller than a wavelength can strongly depolarize backscattered light, thus suggesting that backscattering depolarization for nonspherical particles cannot be universally explained by using only geometric-optics considerations.

  18. Turbulent Flow Past Spinning Cylinders

    NASA Astrophysics Data System (ADS)

    Mehmedagic, Igbal; Carlucci, Donald; Carlucci, Pasquale; Thangam, Siva

    2009-11-01

    Flow past cylinders aligned along their axis where a base freely spins while attached to a non-spinning forebody is considered from a computational and experimental point of view. The time-averaged equations of motion and energy are solved using the modeled form of transport equations for the turbulence kinetic energy and the scalar form of turbulence dissipation with an efficient finite-volume algorithm. An anisotropic two-equation Reynolds-stress model that incorporates the effect of rotation-modified energy spectrum and swirl is used to perform computations for the flow past axially rotating cylinders. Both rigid cylinders as well as that of cylinders with free-spinning base are considered from a computational point of view. A subsonic wind tunnel with a forward-sting mounted spinning cylinder is used for experiments. Experiments are performed for a range of spin rates and free stream flow conditions. The experimental results of Carlucci & Thangam (2001) are used to benchmark flow over spinning cylinders. The data is extended to munitions spinning in the wake of other munitions. Applications involving the design of projectiles are discussed.

  19. Optical emission from a small scale model electric arc furnace in 250-600 nm region

    SciTech Connect

    Maekinen, A.; Tikkala, H.; Aksela, H.; Niskanen, J.

    2013-04-15

    Optical emission spectroscopy has been for long proposed for monitoring and studying industrial steel making processes. Whereas the radiative decay of thermal excitations is always taking place in high temperatures needed in steel production, one of the most promising environment for such studies are electric arc furnaces, creating plasma in excited electronic states that relax with intense characteristic emission in the optical regime. Unfortunately, large industrial scale electric arc furnaces also present a challenging environment for optical emission studies and application of the method is not straightforward. To study the usability of optical emission spectroscopy in real electric arc furnaces, we have developed a laboratory scale DC electric arc furnace presented in this paper. With the setup, optical emission spectra of Fe, Cr, Cr{sub 2}O{sub 3}, Ni, SiO{sub 2}, Al{sub 2}O{sub 3}, CaO, and MgO were recorded in the wavelength range 250-600 nm and the results were analyzed with the help of reference data. The work demonstrates that using characteristic optical emission, obtaining in situ chemical information from oscillating plasma of electric arc furnaces is indeed possible. In spite of complications, the method could possibly be applied to industrial scale steel making process in order to improve its efficiency.

  20. Optical emission from a small scale model electric arc furnace in 250-600 nm region.

    PubMed

    Mäkinen, A; Niskanen, J; Tikkala, H; Aksela, H

    2013-04-01

    Optical emission spectroscopy has been for long proposed for monitoring and studying industrial steel making processes. Whereas the radiative decay of thermal excitations is always taking place in high temperatures needed in steel production, one of the most promising environment for such studies are electric arc furnaces, creating plasma in excited electronic states that relax with intense characteristic emission in the optical regime. Unfortunately, large industrial scale electric arc furnaces also present a challenging environment for optical emission studies and application of the method is not straightforward. To study the usability of optical emission spectroscopy in real electric arc furnaces, we have developed a laboratory scale DC electric arc furnace presented in this paper. With the setup, optical emission spectra of Fe, Cr, Cr2O3, Ni, SiO2, Al2O3, CaO, and MgO were recorded in the wavelength range 250-600 nm and the results were analyzed with the help of reference data. The work demonstrates that using characteristic optical emission, obtaining in situ chemical information from oscillating plasma of electric arc furnaces is indeed possible. In spite of complications, the method could possibly be applied to industrial scale steel making process in order to improve its efficiency.

  1. Effect of blade flutter and electrical loading on small wind turbine noise

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effect of blade flutter and electrical loading on the noise level of two different size wind turbines was investigated at the Conservation and Production Research Laboratory (CPRL) near Bushland, TX. Noise and performance data were collected on two blade designs tested on a wind turbine rated a...

  2. Temporal characteristics of the pulsed electric discharges in small gaps filled with hydrocarbon oil

    NASA Astrophysics Data System (ADS)

    Maradia, U.; Hollenstein, Ch; Wegener, K.

    2015-02-01

    In order to understand the role of electrode materials in electrical discharges with micro gaps (<200 µm) filled with a liquid hydrocarbon dielectric, the post-breakdown phase of low ignition voltage (100 V) and low current (<20 A) pulsed electric discharges is experimentally investigated. The electric discharge energies are selected in the range from 1 to 150 mJ. Due to the non-repetitive and transient nature of the micro-discharges, time-resolved imaging, spectroscopy and electrical analysis of single discharges are performed. The plasma-material interaction is investigated by analysing the erosion craters on anode and cathode. It is found that the electrode materials in these multiphase discharges affect the gas bubble dynamics, the transport properties of the discharge plasmas and the transition from the gaseous to metallic vapour plasma. The change in the energy fractions dissipated in the electrodes in function of the discharge time is influenced by the thermo-physical properties of the electrode materials. The simulation of craters in multiple discharge process requires consideration of the gas bubble dynamics due to different energy fractions and plasma flushing efficiencies.

  3. Homemade Electricity: An Introduction to Small-Scale Wind, Hydro, and Photovoltaic Systems.

    ERIC Educational Resources Information Center

    Smith, Diane

    This report consists of three parts. The first part provides advice (in the form of questions and answers) to prospective individual power producers who are considering investing in electricity-producing systems and in generating their own power. A list of Public Utilities Regulatory Policies Act (PURPA) regulations is included. This legislation…

  4. Exposure to electric power generator noise among small scale business operators in selected communities in Ibadan, Nigeria.

    PubMed

    Ana, Godson R E E; Luqman, Yesufu A; Shendell, Derek G; Owoaje, Eme T

    2014-11-01

    Inadequate and erratic power supplies mean small businesses use electric generators for alternative power. The authors' goal in the study described here was to assess noise from electric generators and impacts in the commercial areas of Agbowo and Ajibode in Ibadan, Nigeria. Noise levels (A-weighted decibels [dBA]) were measured over 12 weeks, three times a day, during the 2010 dry season using a sound level meter. A questionnaire was administered (515 respondents; 304 in Agbowo, 211 in Ajibode) and audiometric measurements were conducted on 40% of respondents. Mean noise levels varied by source (104 ± 7.7 dBA [diesel], 94.0 ± 6.3 dBA [petrol]) and were highest midday (90.6 ± 5.3 dBA [Agbowo], 70.9 ± 6.2 dBA [Ajibode]). Mean noise levels in Agbowo (78.5 ± 3.9 dBA) and Ajibode (65.7 ± 4.4 dBA) exceeded World Health Organization guidelines (65 dBA) for outdoor commercial environments. Working and living in Agbowo was significantly associated with current evidence of hearing impairment (odds ratio: 6.8, 95% confidence interval: 3.4-13.7). Reducing exposure to noise from electric power generators serving urban small businesses and homes is warranted.

  5. Apparatus for measuring Seebeck coefficient and electrical resistivity of small dimension samples using infrared microscope as temperature sensor

    NASA Astrophysics Data System (ADS)

    Jaafar, W. M. N. Wan; Snyder, J. E.; Min, Gao

    2013-05-01

    An apparatus for measuring the Seebeck coefficient (α) and electrical resistivity (ρ) was designed to operate under an infrared microscope. A unique feature of this apparatus is its capability of measuring α and ρ of small-dimension (sub-millimeter) samples without the need for microfabrication. An essential part of this apparatus is a four-probe assembly that has one heated probe, which combines the hot probe technique with the Van der Pauw method for "simultaneous" measurements of the Seebeck coefficient and electrical resistivity. The repeatability of the apparatus was investigated over a temperature range of 40 °C-100 °C using a nickel plate as a standard reference. The results show that the apparatus has an uncertainty of ±4.9% for Seebeck coefficient and ±5.0% for electrical resistivity. The standard deviation of the apparatus against a nickel reference sample is -2.43 μVK-1 (-12.5%) for the Seebeck coefficient and -0.4 μΩ cm (-4.6%) for the electrical resistivity, respectively.

  6. Apparatus for measuring Seebeck coefficient and electrical resistivity of small dimension samples using infrared microscope as temperature sensor.

    PubMed

    Jaafar, W M N Wan; Snyder, J E; Min, Gao

    2013-05-01

    An apparatus for measuring the Seebeck coefficient (α) and electrical resistivity (ρ) was designed to operate under an infrared microscope. A unique feature of this apparatus is its capability of measuring α and ρ of small-dimension (sub-millimeter) samples without the need for microfabrication. An essential part of this apparatus is a four-probe assembly that has one heated probe, which combines the hot probe technique with the Van der Pauw method for "simultaneous" measurements of the Seebeck coefficient and electrical resistivity. The repeatability of the apparatus was investigated over a temperature range of 40 °C-100 °C using a nickel plate as a standard reference. The results show that the apparatus has an uncertainty of ±4.9% for Seebeck coefficient and ±5.0% for electrical resistivity. The standard deviation of the apparatus against a nickel reference sample is -2.43 μVK(-1) (-12.5%) for the Seebeck coefficient and -0.4 μΩ cm (-4.6%) for the electrical resistivity, respectively.

  7. The history of re-connection and the concept of the solar wind plasma with relatively small electrical conductivity

    NASA Technical Reports Server (NTRS)

    Chertkov, A. D.

    1995-01-01

    Petschek's 're-connection' model, aspiring to be universal, treated as a boundary problem meets unresolvable difficulties connected with impossibility to specify correctly boundary and initial conditions. This problem was incorrectly formulated. Hence, ineradicable logarithmic singularities occurred on the boundary surfaces. Attempts to eliminate them by incorporating the finite electrical conductivity are incorrect. This should lead to the change in the equation type, boundary condition type and in consequence to the change in solutions. Besides, the slow mode shocks cannot be driven by small internal source. As an alternative a new plasma concept is suggested. The state of fully ionized plasma in space depends completely on the entropy of the plasma heating source and on the process in which plasma is involved. The presumptive source of the solar wind creation - the induction electric field of the solar origin - has very low entropy. The state of plasma should be very far from the thermodynamic equilibrium. Debye's screening is not complete. The excitation of the powerful resonant self-consistent electric fields in plasma provides low electric conductivity. The MHD problems should be treated in frameworks of dissipative theories.

  8. Adaptronic tools for superfinishing of cylinder bores

    NASA Astrophysics Data System (ADS)

    Roscher, Hans-Jürgen; Hochmuth, Carsten; Hoffmann, Michael; Praedicow, Michael

    2012-04-01

    Today in the production of internal combustion engines it is possible to make pistons as well as cylinders, for all practical purposes, perfectly round. The negative consequences of the subsequent assembly processes and operation of the engine is that the cylinders and pistons are deformed, resulting in a loss of power and an increase in fuel consumption. This problem can be solved by using an adaptronic tool, which can machine the cylinder to a predetermined nonround geometry, which will deform to the required geometry during assembly and operation of the engine. The article describes the actuatory effect of the tool in conjunction with its measuring and controlling algorithms. The adaptronic tool consists out the basic tool body and three axially-staggered floating cutter groups, these cutter groups consist out of guides, actuators and honing stones. The selective expansion of the tool is realised by 3 piezoelectric multilayer-actuators deployed in a series - parallel arrangement. It is also possible to superimpose actuator expansion on the conventional expansion. A process matrix is created during the processing of the required and actual contour data in a technology module. This is then transferred over an interface to the machine controller where it is finally processed and the setting values for the piezoelectric actuators are derived, after which an amplifier generates the appropriate actuator voltages. A slip ring system on the driveshaft is used to transfer the electricity to the actuators in the machining head. The functioning of the adaptronic form-honing tool and process were demonstrated with numerous experiments. The tool provides the required degrees of freedom to generate a contour that correspond to the inverse compound contour of assembled and operational engines.

  9. Thin film deposition by electric and magnetic crossed-field diode sputtering

    DOEpatents

    Welch, Kimo M.

    1977-01-01

    Applying a thin film coating to the surface of a workpiece, in particular, applying a coating of titanium nitride to a klystron window by means of a crossed-field diode sputtering array. The array is comprised of a cohesive group of numerous small hollow electrically conducting cylinders and is mounted so that the open ends of the cylinders on one side of the group are adjacent a titanium cathode plate. The workpiece is mounted so as to face the open ends of the other side of the group. A magnetic field is applied to the array so as to be coaxial with the cylinders and a potential is applied across the cylinders and the cathode plate, the cylinders as an anode being positive with respect to the cathode plate. The cylinders, the cathode plate and the workpiece are situated in an atmosphere of nitrogen which becomes ionized such as by field emission because of the electric field between the cylinders and cathode plate, thereby establishing an anode-cathode discharge that results in sputtering of the titanium plate. The sputtered titanium coats the workpiece and chemically combines with the nitrogen to form a titanium nitride coating on the workpiece. Gas pressure, gas mixtures, cathode material composition, voltages applied to the cathode and anode, the magnetic field, cathode, anode and workpiece spacing, and the aspect ratio (ratio of length to inner diameter) of the anode cylinders, all may be controlled to provide consistent optimum thin film coatings of various compositions and thicknesses. Another facet of the disclosure is the coating of microwave components per se with titanium nitride to reduce multipactoring under operating conditions of the components.

  10. Thin film deposition by electric and magnetic crossed-field diode sputtering. [Patent application

    DOEpatents

    Welch, K.M.

    1975-04-04

    Applying a coating of titanium nitride to a klystron window by means of a cross-field diode sputtering array is described. The array is comprised of a cohesive group of numerous small hollow electrically conducting cylinders and is mounted so that the open ends of the cylinders on one side of the group are adjacent to a titanium cathode plate. The workpiece is mounted so as to face the open ends of the other side of the group. A magnetic field is applied to the array so as to be coaxial with the cylinders and a potential is applied across the cylinders and the cathode plate, the cylinders as an anode being positive with respect to the cathode plate. The cylinders, the cathode plate, and the workpiece are situated in an atmosphere of nitrogen which becomes ionized such as by field emission because of the electric field between the cylinders and cathode plate, thereby establishing an anode-cathode discharge that results in sputtering of the titanium plate. The sputtered titanium coats the workpiece and chemically combines with the nitrogen to form a titanium nitride coating on the workpiece. Gas pressure, gas mixtures, cathode material composition, voltages applied to the cathode and anode, the magnetic field, cathode, anode and workpiece spacing, and the aspect ratio (ratio of length to inner diameter) of the anode cylinders, all may be controlled to provide consistent optimum thin film coatings of various compositions and thickness. Another facet of the disclosure is the coating of microwave components per se with titanium nitride to reduce multifactoring under operating conditions of the components.

  11. Thin film deposition by electric and magnetic crossed-field diode sputtering

    DOEpatents

    Welch, Kimo M.

    1980-01-01

    Applying a thin film coating to the surface of a workpiece, in particular, applying a coating of titanium nitride to a klystron window by means of a crossed-field diode sputtering array. The array is comprised of a cohesive group of numerous small hollow electrically conducting cylinders and is mounted so that the open ends of the cylinders on one side of the group are adjacent a titanium cathode plate. The workpiece is mounted so as to face the open ends of the other side of the group. A magnetic field is applied to the array so as to be coaxial with the cylinders and a potential is applied across the cylinders and the cathode plate, the cylinders as an anode being positive with respect to the cathode plate. The cylinders, the cathode plate and the workpiece are situated in an atmosphere of nitrogen which becomes ionized such as by field emission because of the electric field between the cylinders and cathode plate, thereby establishing an anode-cathode discharge that results in sputtering of the titanium plate. The sputtered titanium coats the workpiece and chemically combines with the nitrogen to form a titanium nitride coating on the workpiece. Gas pressure, gas mixtures, cathode material composition, voltages applied to the cathode and anode, the magnetic field, cathode, anode and workpiece spacing, and the aspect ratio (ratio of length to inner diameter) of the anode cylinders, all may be controlled to provide consistent optimum thin film coatings of various compositions and thicknesses. Another facet of the disclosure is the coating of microwave components per se with titanium nitride to reduce multipactoring under operating conditions of the components.

  12. Highly stable carbon nanotube field emitters on small metal tips against electrical arcing

    PubMed Central

    2013-01-01

    Carbon nanotube (CNT) field emitters that exhibit extremely high stability against high-voltage arcing have been demonstrated. The CNT emitters were fabricated on a sharp copper tip substrate that produces a high electric field. A metal mixture composed of silver, copper, and indium micro- and nanoparticles was used as a binder to attach CNTs to the substrate. Due to the strong adhesion of the metal mixture, CNTs were not detached from the substrate even after many intense arcing events. Through electrical conditioning of the as-prepared CNT emitters, vertically standing CNTs with almost the same heights were formed on the substrate surface and most of loosely bound impurities were removed from the substrate. Consequently, no arcing was observed during the normal operation of the CNT emitters and the emission current remained constant even after intentionally inducing arcing at current densities up to 70 mA/cm2. PMID:23953847

  13. Electricity Customers

    EPA Pesticide Factsheets

    This page discusses key sectors and how they use electricity. Residential, commercial, and industrial customers each account for roughly one-third of the nation’s electricity use. The transportation sector also accounts for a small fraction of electricity.

  14. Filament winding cylinders. I - Process model

    NASA Technical Reports Server (NTRS)

    Lee, Soo-Yong; Springer, George S.

    1990-01-01

    A model was developed which describes the filament winding process of composite cylinders. The model relates the significant process variables such as winding speed, fiber tension, and applied temperature to the thermal, chemical and mechanical behavior of the composite cylinder and the mandrel. Based on the model, a user friendly code was written which can be used to calculate (1) the temperature in the cylinder and the mandrel, (2) the degree of cure and viscosity in the cylinder, (3) the fiber tensions and fiber positions, (4) the stresses and strains in the cylinder and in the mandrel, and (5) the void diameters in the cylinder.

  15. Scattering of a Gaussian beam by a large perfectly conducting cylinder with application to optical sensors

    NASA Astrophysics Data System (ADS)

    Gardner, Judd Steven

    1999-10-01

    Optical proximity sensing is often used in industry and the commercial realm to provide a system with information it may use in some decision making process. The applications for optical proximity sensing have changed and expanded over the years, and has presented a continually increased demand for higher accuracy. In order to satisfy this demand, new optical techniques have been established which have provided more precise proximity data than ever before, e.g. Atomic Force Microscopy and Photothermal Detection. To accommodate the increase in sensing precision, the precision of the mathematical models used to predict the behavior of the optical scheme must also increase. The particular interest pursued in this dissertation involves the detection of the change in the position of a beam due to some phenomena, e.g. Photothermal Deflection or Atomic Force Microscopy. The deflection of the beam in these cases may be on the order of microradians, and too small to detect with ordinary means. To remedy this, a reflecting cylinder is strategically positioned to reflect the incident deflected beam and, by the cylinder geometry, the reflected beam from the cylinder shows an increased deflection angle compared to the incident beam. If the optical scheme has been designed successfully, the resulting deflection of the reflected beam will be large enough to be detected by a sensor. In order to predict the optical behavior of an incident deflected beam reflected from a cylinder, three mathematical methods, Geometrical Optics, Physical Optics, and an Exact Formulation rigorously based on Maxwell's equations are employed. From these methods, a Geometrical Optics solution, two Physical Optics solutions, and an Exact solution are obtained and compared to demonstrate the accuracy of these mathematical models to predict the electric field behavior of a beam reflected from a cylinder. In all cases a Gaussian, well focused beam is used. The near, transitional, and far zones are considered

  16. Torque on a sphere inside a rotating cylinder.

    NASA Technical Reports Server (NTRS)

    Mena, B.; Levinson, E.; Caswell, B.

    1972-01-01

    A circular cylinder of finite dimensions is made to rotate around a sphere fixed in the center of the cylinder. The couple on the sphere is measured over a wide range of rotational speeds for both Newtonian and non-Newtonian fluids. For the Newtonian liquids a comparison of the experimental results is made with Collins' (1955) expansion of the couple as a series in even powers of the angular Reynolds number. For non-Newtonian liquids the apparatus proves to be extremely useful for an accurate determination of the zero shear rate viscosity using only a small amount of fluid.

  17. The Point-Focusing Thermal and Electric Applications Project - A progress report. [small solar power systems applications

    NASA Technical Reports Server (NTRS)

    Marriott, A. T.

    1979-01-01

    The paper discusses the Point-Focusing Thermal and Electric Applications Project which encompasses three primary activities: (1) applications analysis and development, in which potential markets for small power systems (less than 10 MWe) are identified and characterized in order to provide requirements for design and information for activities relating to market development; (2) systems engineering and development, for analyses that will define the most appropriate small power system designs based on specific user requirements; and (3) experiment implementation and test, which deals with the design and placement of engineering experiments in various applications environments in order to test the readiness of the selected technology in an operational setting. Progress to date and/or key results are discussed throughout the text.

  18. Analysis of Hybrid-Electric Propulsion System Designs for Small Unmanned Aircraft Systems

    DTIC Science & Technology

    2010-03-01

    wing cross section data and assumed high-lift devices like flaps would not be used. The upper bound on CL,max should act as an active constraint...finding wing cross-sections with greater lift coefficients or adding high lift devices like flaps , the payload capacity could be dramatically improved...value (J/kg) QLHV Lower heating value (J/kg) Qm Electric motor shaft torque (Nm) r Range (m) R Resistance (Ω) S Wing planform area (m2) SFC

  19. Lightweight Integrated Solar Array and Transceiver. [Improving Electrical Power and Communication Capabilities in Small Spacecraft

    NASA Technical Reports Server (NTRS)

    Carr, John; Martinez, Andres; Petro, Andrew

    2015-01-01

    The Lightweight Integrated Solar Array and Transceiver (LISA-T) project will leverage several existing and on-going efforts at Marshall Space Flight Center (MSFC) for the design, development, fabrication, and test of a launch stowed, orbit deployed structure on which thin-film photovoltaics for power generation and antenna elements for communication, are embedded. Photovoltaics is a method for converting solar energy into electricity using semiconductor materials. The system will provide higher power generation with a lower mass, smaller stowage volume, and lower cost than the state of the art solar arrays, while simultaneously enabling deployable antenna concepts.

  20. Development of a New Generation of Small Scale Biomass-Fueled Electric Generating Power Plants.

    DTIC Science & Technology

    1995-08-01

    Product Gases. Energy from Biomass and Wastes X, Washington, DC, April 7-10, 1986. 2. Newby, R.A., and R.L. Bannister. Hot Gas Cleaning System for Coal ... Gasification Processes, Journal of Engineering for Gas Turbines and Power, April, 1994, Vol. 116, pp. 338. 3. Craig, J.D. Development of a Small

  1. Electric propulsion systems for small satellites: the low earth orbit mission perseus

    NASA Astrophysics Data System (ADS)

    Bock, D.; Herdrich, G.; Lau, M.; Lengowski, M.; Schönherr, T.; Steinmetz, F.; Wollenhaupt, B.; Zeile, O.; Röser, H.-P.

    2011-10-01

    The Institute of Space Systems, Universität Stuttgart, launched a "Small a Satellite Program" in 2002. The first two of the four planed small satellites, Flying Laptop and PERSEUS, are both Low Earth Orbit (LEO) missions. The third mission Cermit is a reentry satellite and the last of the small satellites - Lunar Mission BW1 - is a mission to the Moon. For this purpose, different propulsion systems are mandatory. The propulsion system for Lunar Mission BW1 will consist of two different types of thruster systems: a cluster of pulsed magnetoplasmadynamic (MPD) thrusters (SIMP-LEX) using solid polytetrafluoroethylene (PTFE) as propellant and a thermal arcjet thruster (TALOS) using gaseous ammonia as propellant. Both thruster systems are currently under development at IRS. They are planned to be tested on board the small satellite mission PERSEUS, one of the precursor missions of Lunar Mission BW1. The thruster systems have been investigated intensely in the past and, furthermore, optimization of the thrusters with respect to the mission requirements of Lunar Mission BW1 has been started. The test procedures for the technology demonstration on the PERSEUS satellite are under development at present.

  2. 76 FR 33213 - High Pressure Steel Cylinders from the People's Republic of China: Initiation of Antidumping Duty...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-08

    ... liquefied gas (``high pressure steel cylinders''). High pressure steel cylinders are fabricated of chrome... manufacturing differences between the U.S. and the PRC, Petitioner made adjustments to electricity and natural gas. See Initiation Checklist; see also Volume II of the Petition, at 13-14 and Exhibit...

  3. Packing of hard spheres in cylinders and applications

    NASA Astrophysics Data System (ADS)

    Mughal, Adil; Weaire, Denis; Hutzler, Stefan; Chan, Ho Kei

    2014-03-01

    We study the optimal packing of hard spheres in an infinitely long cylinder. Our simulations have yielded dozens of periodic, mechanically stable, structures as the ratio of the cylinder (D) to sphere (d) diameter is varied. Up to D/d =2.715 the densest structures are composed entirely of spheres which are in contact with the cylinder. The density reaches a maximum at discrete values of D/d when a maximum number of contacts are established. These maximal contact packings are of the classic ``phyllotactic'' type, familiar in biology. However, between these points we observe another type of packing, termed line-slip. An analytic understanding of these rigid structures follows by recourse to a yet simpler problem: the packing of disks on a cylinder. We show that maximal contact packings correspond to the perfect wrapping of a honeycomb arrangement of disks around a cylindrical tube. While line-slip packings are inhomogeneous deformations of the honeycomb lattice modified to wrap around the cylinder. Beyond D/d =2.715 the structures are more complex, since they incorporate internal spheres. We review some relevant experiments with hard spheres, small bubbles and discuss similar structures found in nature. We discuss the chirality of these packings and potential applications in photonics.

  4. Flow around a semicircular cylinder with passive flow control mechanisms

    NASA Astrophysics Data System (ADS)

    Hamed, A. M.; Vega, J.; Liu, B.; Chamorro, L. P.

    2017-03-01

    Wind tunnel experiments were performed to study the effect of passive flow control strategies on the wake and drag of a semicircular cylinder of infinite aspect ratio. High-resolution planar particle image velocimetry was used to obtain flow statistics around the semicircular cylinder at Reynolds number Re≈ 3.2× 10^4 based on the cylinder diameter. The control mechanisms under consideration include rigid flaps of various lengths placed at the edges of the structure and a small slot along the symmetry plane of the cylinder. Mean velocity fields reveal the distinctive effects of each passive mechanism on the flow, such as velocity recovery, size of the recirculation bubble and location of the reattachment point. The distributions of turbulence kinetic energy and kinematic shear stress show the modulation of each passive control mechanism on the wake, including the onset and location of the maximum turbulence levels. Instantaneous and mean fields of swirling strength further highlight the role of the passive mechanisms in the vortex dynamics. Drag coefficient for the various cases was estimated indirectly from the flow measurements using a momentum balance. This approach shows that long flaps and slot were able to reduce drag with respect to the base case. The rigid flaps with length coincident with the diameter of the cylinder offered the best performance with drag reduction of ˜25%.

  5. Biological effects of 60-Hz electric fields on small and large laboratory animals

    SciTech Connect

    Phillips, R.D.

    1981-01-01

    Rats and mice were exposed to 60-Hz electric fields up to 330 kV/m for durations as long as four months. No significant effects were found in the following major areas: metabolic status and growth; organ and tissue morphology; brain morphology; cardiovascular function; serum chemistry; reproduction; prenatal growth and development; teratology; bone growth; peripheral nerve function; humoral and cell-mediated immunity; susceptibility to viral infection; cell and membrane function; illness/malaise; and cytogenetics. Statistically significant effects of electric field exposures were observed in the following areas: bone fracture repair; neonatal development; neuromuscular function; endocrinology; hematology; neurochemistry; urine volume and chemistry; sympathetic nervous system; behavior. It is likely that many of the effects observed are secondary to chronic stimulation of the animal by the field. Our research efforts have shifted to an in-depth investigation of nervous system functions, with emphasis in behavior, neurochemistry, neurophysiology, and dosimetry. Current and future research in these areas will focus on: relationship of effects to field strength and duration of exposure; recovery from observed effects; fundamental understanding of observed effects; fundamental understanding of interaction of field with animal (dosimetry); and biological significance of observed effects. (ERB)

  6. Solitary surface waves on a plasma cylinder

    NASA Astrophysics Data System (ADS)

    Gradov, O. M.; Stenflo, L.

    1983-03-01

    By considering electrostatic surface waves propagating along a plasma cylinder, it is demonstrated that solitary variations in the cylinder radius may appear. The properties of these slow perturbations are determined by the surface wave intensities.

  7. Small Scale Electrical Power Generation from Heat Co-Produced in Geothermal Fluids: Mining Operation

    SciTech Connect

    Clark, Thomas M.; Erlach, Celeste

    2014-12-30

    Demonstrate the technical and economic feasibility of small scale power generation from low temperature co-produced fluids. Phase I is to Develop, Design and Test an economically feasible low temperature ORC solution to generate power from lower temperature co-produced geothermal fluids. Phase II &III are to fabricate, test and site a fully operational demonstrator unit on a gold mine working site and operate, remotely monitor and collect data per the DOE recommended data package for one year.

  8. Rotating Cylinder Treatment System Demonstration

    EPA Science Inventory

    In August 2008, a rotating cylinder treatment system (RCTSTM) demonstration was conducted near Gladstone, CO. The RCTSTM is a novel technology developed to replace the aeration/oxidation and mixing components of a conventional lime precipitation treatment s...

  9. Video Analysis of Rolling Cylinders

    ERIC Educational Resources Information Center

    Phommarach, S.; Wattanakasiwich, P.; Johnston, I.

    2012-01-01

    In this work, we studied the rolling motion of solid and hollow cylinders down an inclined plane at different angles. The motions were captured on video at 300 frames s[superscript -1], and the videos were analyzed frame by frame using video analysis software. Data from the real motion were compared with the theory of rolling down an inclined…

  10. Turbulent Flow Between Rotating Cylinders

    NASA Technical Reports Server (NTRS)

    Shih-I, Pai

    1943-01-01

    The turbulent air flow between rotating cylinders was investigated. The distributions of mean speed and of turbulence were measured in the gap between a rotating inner and a stationary outer cylinder. The measurements led to the conclusion that the turbulent flow in the gap cannot be considered two dimensional, but that a particular type of secondary motion takes place. It is shown that the experimentally found velocity distribution can be fully understood under the assumption that this secondary motion consists of three-dimensional ring-shape vortices. The vortices occur only in pairs, and their number and size depend on the speed of the rotating cylinder; the number was found to decrease with increasing speed. The secondary motion has an essential part in the transmission of the moment of momentum. In regions where the secondary motion is negligible, the momentum transfer follows the laws known for homologous turbulence. Ring-shape vortices are known to occur in the laminar flow between rotating cylinders, but it was hitherto unknown that they exist even at speeds that are several hundred times the critical limit.

  11. Methods for forming small-volume electrical contacts and material manipulations with fluid microchannels

    DOEpatents

    Jacobson, Stephen C [Knoxville, TN; Ramsey, J Michael [Knoxville, TN; Culbertson, Christopher T [Oak Ridge, TN; Whitten, William B [Lancing, TN; Foote, Robert S [Oak Ridge, TN

    2011-12-27

    A microfabricated device employing a bridging membrane and methods for electrokinetic transport of a liquid phase biological or chemical material using the same are described. The bridging membrane is deployed in or adjacent to a microchannel and permits either ionic current flow or the transport of gas species, while inhibiting the bulk flow of material. The use of bridging membranes in accordance with this invention is applicable to a variety of processes, including electrokinetically induced pressure flow in a region of a microchannel that is not influenced by an electric field, sample concentration enhancement and injection, as well as improving the analysis of materials where it is desired to eliminate electrophoretic bias. Other applications of the bridging membranes according to this invention include the separation of species from a sample material, valving of fluids in a microchannel network, mixing of different materials in a microchannel, and the pumping of fluids.

  12. Methods for forming small-volume electrical contacts and material manipulations with fluidic microchannels

    DOEpatents

    Jacobson, Stephen C [Knoxville, TN; Ramsey, J Michael [Knoxville, TN; Culbertson, Christopher T [Oak Ridge, TN; Whitten, William B [Lancing, TN; Foote, Robert S [Oak Ridge, TN

    2011-03-22

    A microfabricated device employing a bridging membrane and methods for electrokinetic transport of a liquid phase biological or chemical material using the same are described. The bridging membrane is deployed in or adjacent to a microchannel and permits either ionic current flow or the transport of gas species, while inhibiting the bulk flow of material. The use of bridging membranes in accordance with this invention is applicable to a variety of processes, including electrokinetically induced pressure flow in a region of a microchannel that is not influenced by an electric field, sample concentration enhancement and injection, as well as improving the analysis of materials where it is desired to eliminate electrophoretic bias. Other applications of the bridging membranes according to this invention include the separation of species from a sample material, valving of fluids in a microchannel network, mixing of different materials in a microchannel, and the pumping of fluids.

  13. Methods for forming small-volume electrical contacts and material manipulations with fluidic microchannels

    DOEpatents

    Jacobson, Stephen C.; Ramsey, J. Michael; Culbertson, Christopher T.; Whitten, William B.; Foote, Robert S.

    2011-04-26

    A microfabricated device employing a bridging membrane and methods for electrokinetic transport of a liquid phase biological or chemical material using the same are described. The bridging membrane is deployed in or adjacent to a microchannel and permits either ionic current flow or the transport of gas species, while inhibiting the bulk flow of material. The use of bridging membranes in accordance with this invention is applicable to a variety of processes, including electrokinetically induced pressure flow in a region of a microehannel that is not influenced by an electric field, sample concentration enhancement and injection, as well as improving the analysis of materials where it is desired to eliminate electrophoretic bias. Other applications of the bridging membranes according to this invention include the separation of species from a sample material, valving of fluids in a microchannel network, mixing of different materials in a microchannel, and the pumping of fluids.

  14. Methods for forming small-volume electrical contacts and material manipulations with fluidic microchannels

    DOEpatents

    Jacobson, Stephen C.; Ramsey, J. Michael; Culbertson, Christopher T.; Whitten, William B.; Foote, Robert S.

    2004-02-03

    A microfabricated device employing a bridging membrane and methods for electrokinetic transport of a liquid phase biological or chemical material using the same are described. The bridging membrane is deployed in or adjacent to a microchannel and permits either ionic current flow or the transport of gas species, while inhibiting the bulk flow of material. The use of bridging membranes in accordance with this invention is applicable to a variety of processes, including electrokinetically induced pressure flow in a region of a microchannel that is not influenced by an electric field, sample concentration enhancement and injection, as well as improving the analysis of materials where it is desired to eliminate electrophoretic bias. Other applications of the bridging membranes according to this invention include the separation of species from a sample material, valving of fluids in a microchannel network, mixing of different materials in a microchannel, and the pumping of fluids.

  15. Methods for forming small-volume electrical contacts and material manipulations with fluidic microchannels

    DOEpatents

    Jacobson, Stephen C.; Ramsey, J. Michael

    2007-11-20

    A microfabricated device employing a bridging membrane and methods for electrokinetic transport of a liquid phase biological or chemical material using the same are described. The bridging membrane is deployed in or adjacent to a microchannel and permits either ionic current flow or the transport of gas species, while inhibiting the bulk flow of material. The use of bridging membranes in accordance with this invention is applicable to a variety of processes, including electrokinetically induced pressure flow in a region of a microchannel that is not influenced by an electric field, sample concentration enhancement and injection, as well as improving the analysis of materials where it is desired to eliminate electrophoretic bias. Other applications of the bridging membranes according to this invention include the separation of species from a sample material, valving of fluids in a microchannel network, mixing of different materials in a microchannel, and the pumping of fluids.

  16. Externally pressurized porous cylinder for multiple surface aerosol generation and method of generation

    DOEpatents

    Apel, Charles T.; Layman, Lawrence R.; Gallimore, David L.

    1988-01-01

    A nebulizer for generating aerosol having small droplet sizes and high efficiency at low sample introduction rates. The nebulizer has a cylindrical gas permeable active surface. A sleeve is disposed around the cylinder and gas is provided from the sleeve to the interior of the cylinder formed by the active surface. In operation, a liquid is provided to the inside of the gas permeable surface. The gas contacts the wetted surface and forms small bubbles which burst to form an aerosol. Those bubbles which are large are carried by momentum to another part of the cylinder where they are renebulized. This process continues until the entire sample is nebulized into aerosol sized droplets.

  17. Comparison of aerodynamic noise from three nose-cylinder combinations

    NASA Technical Reports Server (NTRS)

    Guenther, R. A.; Reding, M. P.

    1970-01-01

    Results of experiments with three different cylinder and blunted nose combinations are discussed. Combinations include smooth cylinder with single 15 deg cone, smooth cylinder with double cone of 25 and 10 deg, and longitudinally corrugated cylinder with similar double cone.

  18. Size Effect in Ferroelectric Long Cylinders

    NASA Astrophysics Data System (ADS)

    Wang, Yuguo; Zhang, Peilin; Wang, Chunlei; Zhong, Weilie; N, Napp; D, R. Tilly

    1995-02-01

    The Curie temperature and polarization in a ferroelectric cylinder with infinite length have been examined using Landau free energy expansion. The Curie temperature and polarization decrease with decreasing cylinder diameter for the positive extrapolation length, and reach zero at the critical size. For negative extrapolation length, both Curie temperature and polarization increase with decreasing cylinder diameter.

  19. The demagnetizing energies of a uniformly magnetized cylinder with an elliptic cross-section

    NASA Astrophysics Data System (ADS)

    Goode, D. A.; Rowlands, G.

    2003-12-01

    Analytic expressions for the demagnetizing energies are obtained in the form of partial series, for long elliptic cylinders and for squat ones where the ellipticity of the cross-section is unrestrained. This leaves just a small range where the demagnetizing energies are not well defined. It is found that by replacing the elliptic cylinders with rectangular blocks, a good approximation to the demagnetizing energy may be made in this small range.

  20. The Effect of Baffles on the Temperature Distribution and Heat-transfer Coefficients of Finned Cylinders

    NASA Technical Reports Server (NTRS)

    Schey, Oscar W; Rollin, Vern G

    1936-01-01

    This report presents the results of an investigation to determine the effect of baffles on the temperature distribution and the heat-transfer coefficient of finned cylinders. The tests were conducted in a 30-inch wind tunnel on electrically heated cylinders with fins of 0.25 and 0.31 inch pitch. The results of these tests showed that the use of integral baffles gave a reduction of 31.9 percent in the rear wall temperatures and an increase of 54.2 percent in the heat transfer coefficient as compared with a cylinder without baffles.

  1. A study of mass production and installation of small solar thermal electric power systems

    NASA Technical Reports Server (NTRS)

    Butterfield, J. F.

    1980-01-01

    Technological constraints, materials availability, production capacity, and manufacturing and installations plans and costs at different production levels are included in a study of concentrating collector industrialization. As cobalt for the engine and receiver is supply limited, alternative lower temperature alloys and higher temperature materials such as ceramics are discussed. Economics and production efficiency favor co-location of cellular and thin glass production for reflectors. Assembly and installation are expensive for small sites and few alternatives exist to apply mass production techniques to lower these costs for the selected design. Stepping motors in the size and quantities required are not commercially available today but could be in the future.

  2. Microwave scattering diagrams of three-layered SiC-metamaterial/gyrotropic ferrite-SiC cylinders

    NASA Astrophysics Data System (ADS)

    Bucinskas, Juozas; Nickelson, Liudmila; Martavicius, Romanas

    2014-05-01

    We present here for the first time the rigorous solution of the boundary diffraction problem of microwave scattering by a multilayered 2D cylinder. The cylinder layers may be made of isotropic, uniaxial anisotropic, electrically and (or) magnetically gyrotropic materials. The number and thickness of the layers may have arbitrary values in our solution. We calculated scattering diagrams (a radial component of real part of the Poynting vector) inside and outside of cylinder using the solution. Here we present scattering diagrams from a three-layered cylinder made of SiC and metamaterial or saturate magnetized ferrite. Diagrams were computed for wave incidence angles θ= π/2, π/3, π/6 inside of metamaterial/ferrite layer at a distance of 1 mm and outside of cylinder at a distance of 2.5 mm from the cylinder axis.

  3. Radiation cross-linking of small electrical wire insulator fabricated from NR/LDPE blends

    NASA Astrophysics Data System (ADS)

    Siri-Upathum, Chyagrit; Punnachaiya, Suvit

    2007-12-01

    A low voltage, radiation-crosslinked wire insulator has been fabricated from blends of natural rubber block (STR-5L) and LDPE with phthalic anhydride (PA) as a compatibilizer. Physical properties of the NR/LDPE blend ratios of 50/50 and 60/40 with 0.5, 1.0, and 1.5 wt% PA were evaluated. The gel content increased as the radiation dose increased. Tensile at break exhibited a maximum value of 12 MPa at 120 kGy for 1.0 and 1.5 wt% PA of both blend ratios. A higher PA content yielded a higher modulus for the same blend ratio. Blends of 60/40 ratio with 1.0 wt% PA and 0.8 wt% antimony oxide flame retardant gave the highest limiting oxygen index (LOI) of >30% at above 150 kGy. Other electrical properties of the wire insulator were investigated. It was found that an insulator fabricated from a PA content of 1.0 wt% in the NR/LDPE blend ratio of 50/50, after gamma ray cross-linked at a dose of 180 kGy in low vacuum (1 mm Hg), met the Thai Industrial Standard 11-2531 for low voltage wire below 1.0 kV. To comply with the standard for vertical flame test, a more suitable flame retardant was needed for the insulator.

  4. Electric fields associated with small-scale magnetic holes in the plasma sheet: Evidence for electron currents

    NASA Astrophysics Data System (ADS)

    Goodrich, Katherine A.; Ergun, Robert E.; Stawarz, Julia E.

    2016-06-01

    We report observations of magnetic holes (MHs) in the near-Earth (8 RE to 12 RE) plasma sheet that have physical sizes perpendicular to the magnetic field (B) on the order of the ion Larmor radius (ρi) and, more importantly, have current layers less than ρi in thickness. Small-scale MHs can have >90% depletion in |B| and are commonly associated with the braking of bursty bulk flow events. The generation of MHs is often attributed to magnetohydrodynamic (MHD) instabilities, which requires a size greater than ρi; the depletion in |B| is from an ion current consistent with a pressure gradient. Electric field (E) observations indicate a negative potential inside of small-scale MHs that creates an outward E at the boundary, which drives an E × B electron current in a thin layer. These observations indicate that a Hall electron current is primarily responsible for the depletion of |B| in small-scale magnetic holes, rather than the ion pressure gradient.

  5. A device for precision neutralization of electric charge of small drops using ionized air

    NASA Astrophysics Data System (ADS)

    Fan, Sewan; Kim, Peter C.; Lee, Eric R.; Lee, Irwin T.; Perl, Martin L.; Rogers, Howard; Loomba, Dinesh

    2003-10-01

    For use in our Millikan type liquid drop searches for fractional charge elementary particles we have developed a simple ionized air device for neutralizing a narrow stream of small drops. The neutralizer has been used for drops ranging in diameter from 10 to 25 μm. The width of the produced charge distribution is given by the Boltzmann equilibrium charge distribution and the mean of the distribution is set by a bias voltage. Using the bias voltage, the mean can be set with a precision of better than e, the electron charge. The use of the neutralizer is illustrated in an application to mineral oil drops produced with charges of the order of 1000e. We also show the interesting case of silicone oil drops that are produced in our drop generator with a charge distribution narrower than the Boltzmann equilibrium charge distribution, the charge distribution being broadened by the neutralizer.

  6. Electrical Thermometers for Aircraft

    NASA Technical Reports Server (NTRS)

    Peterson, John B; Womack, S H J

    1937-01-01

    Electrical thermometers commonly used on aircraft are the thermoelectric type for measuring engine-cylinder temperatures, the resistance type for measuring air temperatures, and the superheat meters of thermoelectric and resistance types for use on airships. These instruments are described and their advantages and disadvantages enumerated. Methods of testing these instruments and the performance to be expected from each are discussed. The field testing of engine-cylinder thermometers is treated in detail.

  7. A study of the air movement in two aircraft-engine cylinders

    NASA Technical Reports Server (NTRS)

    Lee, Dana W

    1940-01-01

    Studies were made of the air movements in the NACA glass-cylinder apparatus using cylinder heads similar to those on the Wright R-1820-G engine and the Pratt & Whitney Wasp engine as modified by the Eclipse Aviation Corporation to use fuel-injection equipment. The air movements were made visible by mixing small feathers with the air; high-speed motion pictures were than taken of the feathers as they swirled about the inside the glass cylinder. The test engine speeds were 350, 500, and 1,000 r.p.m. Motion pictures were also taken of gasoline sprays injected into the cylinder during the intake stroke. The air flow produced by each cylinder head is described and some results of the velocity measurements of feathers are presented. The apparent time intervals required for vaporization of the gasoline sprays are also given.

  8. Prototype Radiation Detector Positioning System For The Automated Nondestructive Assay Of Uf6 Cylinders

    SciTech Connect

    Hatchell, Brian K.; Valdez, Patrick LJ; Orton, Christopher R.; Mace, Emily K.

    2011-08-07

    International Atomic Energy Agency (IAEA) inspectors currently perform periodic inspections at uranium enrichment plants to verify UF6 cylinder enrichment declarations. Measurements are typically performed with handheld high-resolution sensors on a sampling of cylinders taken to be representative of the facility’s entire cylinder inventory. These measurements are time-consuming, expensive, and assay only a small fraction of the total cylinder volume. An automated nondestructive assay system capable of providing enrichment measurements over the full volume of the cylinder could improve upon current verification practices in terms of efficiency and assay accuracy. This paper describes an approach denoted the Integrated Cylinder Verification Station (ICVS) that supports 100% cylinder verification, provides volume-averaged cylinder enrichment assay, and reduces inspector manpower needs. To allow field measurements to be collected to validate data collection algorithms, a prototype radiation detector positioning system was constructed. The system was designed to accurately position an array of radiation detectors along the length of a cylinder to measure UF6 enrichment. A number of alternative radiation shields for the detectors were included with the system. A collimated gamma-ray spectrometer module that allows translation of the detectors in the surrounding shielding to adjust the field of view, and a collimating plug in the end to further reduce the low-energy field of view, were also developed. Proof-of-principle measurements of neutron and high-energy gamma-ray signatures, using moderated neutron detectors and large-volume spectrometers in a fixed-geometry, portal-like configuration, supported an early assessment of the viability of the concept. The system has been used successfully on two testing campaigns at an AREVA fuel fabrication plant to scan over 30 product cylinders. This paper will describe the overall design of the detector positioning system and

  9. Stratified spin-up in a sliced, square cylinder

    SciTech Connect

    Munro, R. J.; Foster, M. R.

    2014-02-15

    We previously reported experimental and theoretical results on the linear spin-up of a linearly stratified, rotating fluid in a uniform-depth square cylinder [M. R. Foster and R. J. Munro, “The linear spin-up of a stratified, rotating fluid in a square cylinder,” J. Fluid Mech. 712, 7–40 (2012)]. Here we extend that analysis to a “sliced” square cylinder, which has a base-plane inclined at a shallow angle α. Asymptotic results are derived that show the spin-up phase is achieved by a combination of the Ekman-layer eruptions (from the perimeter region of the cylinder's lid and base) and cross-slope-propagating stratified Rossby waves. The final, steady state limit for this spin-up phase is identical to that found previously for the uniform depth cylinder, but is reached somewhat more rapidly on a time scale of order E{sup −1/2}Ω{sup −1}/log (α/E{sup 1/2}) (compared to E{sup −1/2}Ω{sup −1} for the uniform-depth cylinder), where Ω is the rotation rate and E the Ekman number. Experiments were performed for Burger numbers, S, between 0.4 and 16, and showed that for S≳O(1), the Rossby modes are severely damped, and it is only at small S, and during the early stages, that the presence of these wave modes was evident. These observations are supported by the theory, which shows the damping factors increase with S and are numerically large for S≳O(1)

  10. Electrical properties of diluted n- and p-Si{sub 1−x}Ge{sub x} at small x

    SciTech Connect

    Emtsev, V. V.; Abrosimov, N. V.; Kozlovskii, V. V.; Oganesyan, G. A.

    2014-12-15

    Hall effect and conductivity measurements are taken on Si{sub 1−x}Ge{sub x} of n- and p-type at x ≤ 0.05. Much attention is given to electrical measurements over a temperature interval of 25 to 40 K where the mobility of charged carriers is strongly affected by alloy scattering. The partial mobility of electrons and holes due to this scattering mechanism is estimated for n-Si{sub 1−x}Ge{sub x} and p-Si{sub 1−x}Ge{sub x} at small x. Together with this, an effect of the presence of Ge atoms upon the ionization energy of phosphorus and boron impurities is investigated. Some points related to an inhomogeneous distribution of Ge atoms in Si{sub 1−x}Ge{sub x} are discussed.

  11. Solid State Digital Propulsion "Cluster Thrusters" For Small Satellites Using High Performance Electrically Controlled Extinguishable Solid Propellants (ECESP)

    NASA Technical Reports Server (NTRS)

    Sawka, Wayne N.; Katzakian, Arthur; Grix, Charles

    2005-01-01

    Electrically controlled extinguishable solid propellants (ESCSP) are capable of multiple ignitions, extinguishments and throttle control by the application of electrical power. Both core and end burning no moving parts ECESP grains/motors to three inches in diameter have now been tested. Ongoing research has led to a newer family of even higher performance ECESP providing up to 10% higher performance, manufacturing ease, and significantly higher electrical conduction. The high conductivity was not found to be desirable for larger motors; however it is ideal for downward scaling to micro and pico- propulsion applications with a web thickness of less than 0.125 inch/ diameter. As a solid solution propellant, this ECESP is molecularly uniform, having no granular structure. Because of this homogeneity and workable viscosity it can be directly cast into thin layers or vacuum cast into complex geometries. Both coaxial and grain stacks have been demonstrated. Combining individual propellant coaxial grains and/or grain stacks together form three-dimensional arrays yield modular cluster thrusters. Adoption of fabless manufacturing methods and standards from the electronics industry will provide custom, highly reproducible micro-propulsion arrays and clusters at low costs. These stack and cluster thruster designs provide a small footprint saving spacecraft surface area for solar panels and/or experiments. The simplicity of these thrusters will enable their broad use on micro-pico satellites for primary propulsion, ACS and formation flying applications. Larger spacecraft may find uses for ECESP thrusters on extended booms, on-orbit refueling, pneumatic actuators, and gas generators.

  12. Conjugate natural convection between horizontal eccentric cylinders

    NASA Astrophysics Data System (ADS)

    Nasiri, Davood; Dehghan, Ali Akbar; Hadian, Mohammad Reza

    2017-03-01

    This study involved the numerical investigation of conjugate natural convection between two horizontal eccentric cylinders. Both cylinders were considered to be isothermal with only the inner cylinder having a finite wall thickness. The momentum and energy equations were discretized using finite volume method and solved by employing SIMPLER algorithm. Numerical results were presented for various solid-fluid conductivity ratios ( KR) and various values of eccentricities in different thickness of inner cylinder wall and also for different angular positions of inner cylinder. From the results, it was observed that in an eccentric case, and for KR < 10, an increase in thickness of inner cylinder wall resulted in a decrease in the average equivalent conductivity coefficient (overline{{K_{eq} }}); however, a KR > 10 value caused an increase in overline{{K_{eq} }}. It was also concluded that in any angular position of inner cylinder, the value of overline{{K_{eq} }} increased with increase in the eccentricity.

  13. The Study and Implementation of Electrically Small Printed Antennas for an Integrated Transceiver Design

    SciTech Connect

    Speer, Pete

    2009-04-28

    This work focuses on the design and evaluation of the inverted-F, meandering-monopole, and loop antenna geometries. These printed antennas are studied with the goal of identifying which is suitable for use in a miniaturized transceiver design and which has the ability to provide superior performance using minimal Printed Circuit Board (PCB) space. As a result, the main objective is to characterize tradeoffs and identify which antenna provides the best compromise among volume, bandwidth and efficiency. For experimentation purposes, three types of meandering-monopole antenna are examined resulting in five total antennas for the study. The performance of each antenna under study is evaluated based upon return loss, operational bandwidth, and radiation pattern characteristics. For our purposes, return loss is measured using the S11-port reflection coefficient which helps to characterize how well the small antenna is able to be efficiently fed. Operational bandwidth is measured as the frequency range over which the antenna maintains 2:1 Voltage Standing Wave Ratio (VSWR) or equivalently has 10-dB return loss. Ansoft High Frequency Structure Simulator (HFSS) is used to simulate expected resonant frequency, bandwidth, VSWR, and radiation pattern characteristics. Ansoft HFSS simulation is used to provide a good starting point for antenna design before actual prototype are built using an LPKF automated router. Simulated results are compared with actual measurements to highlight any differences and help demonstrate the effects of antenna miniaturization. Radiation characteristics are measured illustrating how each antenna is affected by the influence of a non-ideal ground plane. The antenna with outstanding performance is further evaluated to determine its maximum range of communication. Each designs range performance is evaluated using a pair of transceivers to demonstrate round-trip communication. This research is intended to provide a knowledge base which will help

  14. Generalized Bistability in Origami Cylinders

    NASA Astrophysics Data System (ADS)

    Reid, Austin; Adda-Bedia, Mokhtar; Lechenault, Frederic

    Origami folded cylinders (origami bellows) have found increasingly sophisticated applications in space flight, medicine, and even experimental nuclear physics. In spite of this interest, a general understanding of the dynamics of an origami folded cylinder has been elusive. By solving the fully constrained behavior of a periodic fundamental origami cell defined by unit vectors, we have found an analytic solution for all possible rigid-face states accessible from a cylindrical Miura-ori pattern. Although an idealized bellows has two rigid-face configurations over a well-defined region, a physical device, limited by nonzero material thickness and forced to balance hinge with plate-bending energy, often cannot stably maintain a stowed configuration. We have identified and measured the parameters which control this emergent bistability, and have demonstrated the ability to fabricate bellows with tunable deployability.

  15. Small solar electric system components demonstration. [thermal storage modules for Brayton systems

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The design and testing of high temperature thermal storage modules (TSM) are reported. The test goals were to demonstrate the thermocline propagation in the TSM, to measure the steepness of the thermocline, and to measure the effectiveness of the TSM when used in a Brayton system. In addition, a high temperature valve suitable for switching the TSM at temperatures to 1700 F is described and tested. Test results confirm the existence of a sharp thermocline under design conditions. The thermal profile was steeper than expected and was insensitive to air density over the range of the test conditions. Experiments were performed which simulated the airflow of a small Brayton engine, 20 KWe, having a pair of thermal storage modules acting as efficient recuperators. Low pressure losses, averaging 12 inches of water, and high effectiveness, 93% for a 15 minute switching cycle, were measured. The insulation surrounding the ceramic core limited thermal losses to approximately 1 KWt. The hot valve was operated over 100 cycles and performed well at temperatures up to 1700 F.

  16. The Electric and Optical Properties of Doped Small Molecular Organic Light-Emitting Devices

    SciTech Connect

    Cheon, Kwang-Ohk

    2003-01-01

    Organic light-emitting devices (OLEDs) constitute a new and exciting emissive display technology. In general, the basic OLED structure consists of a stack of fluorescent organic layers sandwiched between a transparent conducting-anode and metallic cathode. When an appropriate bias is applied to the device, holes are injected from the anode and electrons from the cathode; some of the recombination events between the holes and electrons result in electroluminescence (EL). Until now, most of the efforts in developing OLEDs have focused on display applications, hence on devices within the visible range. However some organic devices have been developed for ultraviolet or infrared emission. Various aspects of the device physics of doped small molecular OLEDs were described and discussed. The doping layer thickness and concentration were varied systematically to study their effects on device performances, energy transfer, and turn-off dynamics. Low-energy-gap DCM2 guest molecules, in either α-NPD or DPVBi host layers, are optically efficient fluorophores but also generate deep carrier trap-sites. Since their traps reduce the carrier mobility, the current density decreases with increased doping concentration. At the same time, due to efficient energy transfer, the quantum efficiency of the devices is improved by light doping or thin doping thickness, in comparison with the undoped neat devices. However, heavy doping induces concentration quenching effects. Thus, the doping concentration and doping thickness may be optimized for best performance.

  17. Evaluating Interventions in the U.S. Electricity System: Assessments of Energy Efficiency, Renewable Energy, and Small-Scale Cogeneration

    NASA Astrophysics Data System (ADS)

    Siler-Evans, Kyle

    to evaluate the effects of an additional wind turbine or solar panel in the U.S. electricity system. I find that the most attractive sites for renewables depend strongly on one's objective. A solar panel in Iowa displaces 20% more CO2 emissions than a panel in Arizona, though energy production from the Iowa panel is 25% less. Similarly, despite a modest wind resource, a wind turbine in West Virginia is expected to displace 7 times more health and environmental damages than a wind turbine in Oklahoma. Finally, I shift focus and explore the economics of small-scale cogeneration, which has long been recognized as a more efficient alternative to central-station power. Although the benefits of distributed cogeneration are widely cited, adoption has been slow in the U.S. Adoption could be encouraged by making cogeneration more economically attractive, either by increasing the expected returns or decreasing the risks of such investments. I present a case study of a 300-kilowatt cogeneration unit and evaluate the expected returns from: demand response, capacity markets, regulation markets, accelerated depreciation, a price on CO2 emissions, and net metering. In addition, I explore the effectiveness of feed-in tariffs at mitigating the energy-price risks to cogeneration projects.

  18. Three-dimensional numerical simulation of the flow around two cylinders at supercritical Reynolds number

    NASA Astrophysics Data System (ADS)

    Hu, H. X.; Liu, C. B.; Hu, H. Z.; Zheng, Y. G.

    2013-10-01

    Numerical study of the flow past two tandem cylinders is carried out at P/D = 1.5 and 2.5 for Re = 2.8 × 105-7.0 × 105. The shear-stress transport k-ω turbulence model is selected to capture the flow characteristics around the cylinders. This paper focuses on the characteristics of the fluid field, hydrodynamic forces and vortex-shedding frequencies at two cylinder configurations for different Reynolds numbers (Re). Qualitative and quantitative comparisons with the published data are performed to evaluate the current results and reasonable agreement is obtained. The results show that vortex shedding occurs behind both the upstream and downstream cylinders at P/D = 2.5 for the entire region of testing Re, which is significantly different from the most critical gap spacing (above 3D) at low Re. The drag direction changes from negative at P/D = 1.5 to positive at P/D = 2.5. And the fluctuations found in the lift for the downstream cylinder are more drastic than that for the upstream cylinder, which indicates that the downstream cylinder may behave in large vibration. The Strouhal number (St) at P/D = 1.5 is relatively low compared to that at P/D = 2.5 due to the strong interactions between two cylinders with small gap spacing.

  19. Trade-offs Between Electricity Production from Small Hydropower Plants and Ecosystem Services in Alpine River Basins

    NASA Astrophysics Data System (ADS)

    Meier, Philipp; Schwemmle, Robin; Viviroli, Daniel

    2015-04-01

    The need for a reduction in greenhouse gas emissions and the decision to phase out nuclear power plants in Switzerland and Germany increases pressure to develop the remaining hydropower potential in Alpine catchments. Since most of the potential for large reservoirs is already exploited, future development focusses on small run-of-the-river hydropower plants (SHP). Being considered a relatively environment-friendly electricity source, investment in SHP is promoted through subsidies. However, SHP can have a significant impact on riverine ecosystems, especially in the Alpine region where residual flow reaches tend to be long. An increase in hydropower exploitation will therefore increase pressure on ecosystems. While a number of studies assessed the potential for hydropower development in the Alps, two main factors were so far not assessed in detail: (i) ecological impacts within a whole river network, and (ii) economic conditions under which electricity is sold. We present a framework that establishes trade-offs between multiple objectives regarding environmental impacts, electricity production and economic evaluation. While it is inevitable that some ecosystems are compromised by hydropower plants, the context of these impacts within a river network should be considered when selecting suitable sites for SHP. From an ecological point of view, the diversity of habitats, and therefore the diversity of species, should be maintained within a river basin. This asks for objectives that go beyond lumped parameters of hydrological alteration, but also consider habitat diversity and the spatial configuration. Energy production in run-of-the-river power plants depends on available discharge, which can have large fluctuations. In a deregulated electricity market with strong price variations, an economic valuation should therefore be based on the expected market value of energy produced. Trade-off curves between different objectives can help decision makers to define policies

  20. Ultrastable low-noise current amplifier: A novel device for measuring small electric currents with high accuracy

    SciTech Connect

    Drung, D.; Krause, C.; Becker, U.; Scherer, H.; Ahlers, F. J.

    2015-02-15

    An ultrastable low-noise current amplifier (ULCA) is presented. The ULCA is a non-cryogenic instrument based on specially designed operational amplifiers and resistor networks. It involves two stages, the first providing a 1000-fold current gain and the second performing a current-to-voltage conversion via an internal 1 MΩ reference resistor or, optionally, an external standard resistor. The ULCA’s transfer coefficient is highly stable versus time, temperature, and current amplitude within the full dynamic range of ±5 nA. The low noise level of 2.4 fA/√Hz helps to keep averaging times short at small input currents. A cryogenic current comparator is used to calibrate both input current gain and output transresistance, providing traceability to the quantum Hall effect. Within one week after calibration, the uncertainty contribution from short-term fluctuations and drift of the transresistance is about 0.1 parts per million (ppm). The long-term drift is typically 5 ppm/yr. A high-accuracy variant is available that shows improved stability of the input gain at the expense of a higher noise level of 7.5 fA/√Hz. The ULCA also allows the traceable generation of small electric currents or the calibration of high-ohmic resistors.

  1. AM/FM development for a small electric utility or form partnerships to minimize AM/FM development costs

    SciTech Connect

    Hahne, R.

    1996-08-01

    Chelan County Public Utility District is a 32,000 customer electric utility in central Washington State. Being a small utility presents unique problems in developing a complex AM/FM system. With only a small staff assigned part-time to this project, partnering and outsourcing became essential for developing an AM/FM system. An incremental approach was also necessary. Our project started in 1992 in partnership with Chelan County and the City of Wenatchee for the development of a common landbase in ARC/INFO. For our AM/FM system, a purchased solution was much more feasible than in-house development. We decided against a big requirements definition phase or a formal RFP, and instead looked at available AM/FM systems to decide what was feasible for us. This paper shares the basics of our partnering strategy and outlines how our approach will allow the project to be completed in a fast-track of 40 months at a minimal cost to the Chelan P.U.D. ratepayers.

  2. Fire testing of bare uranium hexafluoride cylinders

    SciTech Connect

    Pryor, W.A.

    1991-12-31

    In 1965, the Oak Ridge Gaseous Diffusion Plant (ORGDP), now the K-25 Site, conducted a series of tests in which bare cylinders of uranium hexafluoride (UF{sub 6}) were exposed to engulfing oil fires for the US Atomic Energy Commission (AEC), now the US Department of Energy (DOE). The tests are described and the results, conclusions, and observations are presented. Two each of the following types of cylinders were tested: 3.5-in.-diam {times} 7.5-in.-long cylinders of Monel (Harshaw), 5.0-in.-diam {times} x 30-in.-long cylinders of Monel, and 8-in.-diam {times} 48-in.-long cylinders of nickel. The cylinders were filled approximately to the standard UF{sub 6} fill limits of 5, 55, and 250 lb, respectively, with a U-235 content of 0.22%. The 5-in.- and 8-in.-diam cylinders were tested individually with and without their metal valve covers. For the 3.5-in.-diam Harshaw cylinders and the 5.0-in.-diam cylinder without a valve cover, the valves failed and UF{sub 6} was released. The remaining 6 cylinders ruptured explosively in time intervals ranging from about 8.5 to 11 min.

  3. Fire testing of bare uranium hexafluoride cylinders

    SciTech Connect

    Pryor, W.A.

    1991-12-31

    In 1965, the Oak Ridge Gaseous Diffusion Plant (ORGDP), now the K-25 Site, conducted a series of tests in which bare cylinders of uranium hexafluoride (UF{sub 6}) were exposed to engulfing oil fires for the US Atomic Energy Commission (AEC), now the US Department of Energy (DOE). The tests are described and the results, conclusions, and observations are presented. Two each of the following types of cylinders were tested: 3.5-in.-diam {times} 7.5-in.-long cylinders of Monel (Harshaw), 5.0-in.-diam {times} 30-in.-long cylinders of Monel, and 8-in.-diam {times} 48-in.-long cylinders of nickel. The cylinders were filled approximately to the standard UF{sub 6} fill limits of 5, 55, and 250 lb, respectively, with a U-235 content of 0.22%. The 5-in.- and 8-in.-diam cylinders were tested individually with and without their metal valve covers. For the 3.5-in.-diam Harshaw cylinders and the 5.0-in.-diam cylinder without a valve cover the valves failed and UF{sub 6} was released. The remaining cylinders ruptured explosively in time intervals ranging from about 8.5 to 11 min.

  4. Projected Demand and Potential Impacts to the National Airspace System of Autonomous, Electric, On-Demand Small Aircraft

    NASA Technical Reports Server (NTRS)

    Smith, Jeremy C.; Viken, Jeffrey K.; Guerreiro, Nelson M.; Dollyhigh, Samuel M.; Fenbert, James W.; Hartman, Christopher L.; Kwa, Teck-Seng; Moore, Mark D.

    2012-01-01

    Electric propulsion and autonomy are technology frontiers that offer tremendous potential to achieve low operating costs for small-aircraft. Such technologies enable simple and safe to operate vehicles that could dramatically improve regional transportation accessibility and speed through point-to-point operations. This analysis develops an understanding of the potential traffic volume and National Airspace System (NAS) capacity for small on-demand aircraft operations. Future demand projections use the Transportation Systems Analysis Model (TSAM), a tool suite developed by NASA and the Transportation Laboratory of Virginia Polytechnic Institute. Demand projections from TSAM contain the mode of travel, number of trips and geographic distribution of trips. For this study, the mode of travel can be commercial aircraft, automobile and on-demand aircraft. NASA's Airspace Concept Evaluation System (ACES) is used to assess NAS impact. This simulation takes a schedule that includes all flights: commercial passenger and cargo; conventional General Aviation and on-demand small aircraft, and operates them in the simulated NAS. The results of this analysis projects very large trip numbers for an on-demand air transportation system competitive with automobiles in cost per passenger mile. The significance is this type of air transportation can enhance mobility for communities that currently lack access to commercial air transportation. Another significant finding is that the large numbers of operations can have an impact on the current NAS infrastructure used by commercial airlines and cargo operators, even if on-demand traffic does not use the 28 airports in the Continental U.S. designated as large hubs by the FAA. Some smaller airports will experience greater demand than their current capacity allows and will require upgrading. In addition, in future years as demand grows and vehicle performance improves other non-conventional facilities such as short runways incorporated into

  5. Self-sustained criterion with photoionization for positive dc corona plasmas between coaxial cylinders

    SciTech Connect

    Zheng, Yuesheng; Zhang, Bo He, Jinliang

    2015-06-15

    The positive dc corona plasmas between coaxial cylinders in air under the application of a self-sustained criterion with photoionization are investigated in this paper. A photon absorption function suitable for cylindrical electrode, which can characterize the total photons within the ionization region, is proposed on the basis of the classic corona onset criteria. Based on the general fluid model with the self-sustained criterion, the role of photoionization in the ionization region is clarified. It is found that the surface electric field keeps constant under a relatively low corona current, while it is slightly weakened with the increase of the corona current. Similar tendencies can be found under different conductor radii and relative air densities. The small change of the surface electric field will become more significant for the electron density distribution as well as the ionization activity under a high corona current, compared with the results under the assumption of a constant surface field. The assumption that the surface electric field remains constant should be corrected with the increase of the corona current when the energetic electrons with a distance from the conductor surface are concerned.

  6. The control of a parallel hybrid-electric propulsion system for a small unmanned aerial vehicle using a CMAC neural network.

    PubMed

    Harmon, Frederick G; Frank, Andrew A; Joshi, Sanjay S

    2005-01-01

    A Simulink model, a propulsion energy optimization algorithm, and a CMAC controller were developed for a small parallel hybrid-electric unmanned aerial vehicle (UAV). The hybrid-electric UAV is intended for military, homeland security, and disaster-monitoring missions involving intelligence, surveillance, and reconnaissance (ISR). The Simulink model is a forward-facing simulation program used to test different control strategies. The flexible energy optimization algorithm for the propulsion system allows relative importance to be assigned between the use of gasoline, electricity, and recharging. A cerebellar model arithmetic computer (CMAC) neural network approximates the energy optimization results and is used to control the parallel hybrid-electric propulsion system. The hybrid-electric UAV with the CMAC controller uses 67.3% less energy than a two-stroke gasoline-powered UAV during a 1-h ISR mission and 37.8% less energy during a longer 3-h ISR mission.

  7. Subcritical flow past a circular cylinder surrounded by a porous layer

    NASA Astrophysics Data System (ADS)

    Sobera, M. P.; Kleijn, C. R.; Van den Akker, H. E. A.

    2006-03-01

    A study of the flow at subcritical Re =3900 around a circular cylinder, surrounded at some fixed small distance by a porous layer with a hydraulic resistance typical for that of textile materials, has been performed by means of direct numerical simulations. The flow in the space between the porous layer and the solid cylinder was found to be laminar and periodic, with a frequency locked to that of the vortex shedding in the wake behind the cylinder. Time averaged flow velocities underneath the porous material were in good agreement with experimental data from laser Doppler anemometry.

  8. Separation tool for multipin electrical connectors

    NASA Astrophysics Data System (ADS)

    Smith, Larry D.

    1994-07-01

    A hydraulic tool for safely separating one multipin electrical connector from another is presented. The separation tool consists of a master cylinder which operates a pair of slave cylinders. Each slave cylinder has a corresponding operative shaft and an extraction tab. The slave cylinders are spaced apart from one another so that they may be positioned on either side of mated connector pairs of different sizes and so that their extraction tabs may be slid between the connectors. When the master cylinder's plunger is operated, its operation is hydraulically transmitted to the operative shafts of the slave cylinders which extend outward and, once pressed against a substrate, causes the slave cylinders and corresponding extractor tabs to move away and separate one connector from the other. A second preferred separation tool includes an additional pair of extractor tabs, one at the end of each operative shaft, so that the tool can be used to separate a mated connector pair hanging in free space.

  9. Separation tool for multipin electrical connectors

    NASA Astrophysics Data System (ADS)

    Smith, Larry D.

    1993-03-01

    A hydraulic tool for safely separating one multipin electrical connector from another is presented. The separation tool consists of a master cylinder which operates a pair of slave cylinders. Each slave cylinder has a corresponding operative shaft and an extraction tab. The slave cylinders are spaced apart from one another so that they may be positioned on either side of mated connector pairs of different sizes and so that their extraction tabs may be slid between the connectors. When the master cylinder's plunger is operated, its operation is hydraulically transmitted to the operative shafts of the slave cylinders which extend outward and, once pressed against a substrate, causes the slave cylinders and corresponding extractor tabs to move away and separate one connector from the other. A second preferred separation tool includes an additional pair of extractor tabs, one at the end of each operative shaft, so that the tool can be used to separate a mated connector pair hanging in free space.

  10. Natural convection between a vertical cylinder and a surrounding array

    SciTech Connect

    McEligot, D.M.; O'Brien, J.E.; Stoots, C.M.; Larson, T.K.; Christenson, W.A.; Mecham, D.C.; Lussie, W.G.

    1992-01-01

    The generic situation considered is natural convection between a single heated, vertical cylinder and a surrounding array of cooler vertical cylinders in a triangular pattern. The ratio of the test section temperature to the cooling tube temperature was varied up to 2.6 by adjusting the electrical power. The Rayleigh number, based on test section diameter and air properties evaluated at cooling tube temperature, ranged from 2.9 x 10{sup 4} to 4.6 x 10{sup 5}. Results indicate that the convective heat transfer data could be approximated as Nu{sub D} (T{sub ts}/T{sub ct}){sup 0.14} = 0.156 Ra{sub D}{sup 1/3} in the apparent turbulent region for Ra{sub L} > 1.2 x 10{sup 11.}

  11. Natural convection between a vertical cylinder and a surrounding array

    SciTech Connect

    McEligot, D.M.; O`Brien, J.E.; Stoots, C.M.; Larson, T.K.; Christenson, W.A.; Mecham, D.C.; Lussie, W.G.

    1992-09-01

    The generic situation considered is natural convection between a single heated, vertical cylinder and a surrounding array of cooler vertical cylinders in a triangular pattern. The ratio of the test section temperature to the cooling tube temperature was varied up to 2.6 by adjusting the electrical power. The Rayleigh number, based on test section diameter and air properties evaluated at cooling tube temperature, ranged from 2.9 x 10{sup 4} to 4.6 x 10{sup 5}. Results indicate that the convective heat transfer data could be approximated as Nu{sub D} (T{sub ts}/T{sub ct}){sup 0.14} = 0.156 Ra{sub D}{sup 1/3} in the apparent turbulent region for Ra{sub L} > 1.2 x 10{sup 11.}

  12. GLOBAL MONITORING OF URANIUM HEXIFLORIDE CYLINDERS NEXT STEPS IN DEVELOPMENT OF AN ACTION PLAN

    SciTech Connect

    Hanks, D.

    2010-06-09

    Over 40 industrial facilities world-wide use standardized uranium hexafluoride (UF{sub 6}) cylinders for transport, storage and in-process receiving in support of uranium conversion, enrichment and fuel fabrication processes. UF{sub 6} is processed and stored in the cylinders, with over 50,000 tU of UF{sub 6} transported each year in these International Organization for Standardization (ISO) qualified containers. Although each cylinder is manufactured to an ISO standard that calls for a nameplate with the manufacturer's identification number (ID) and the owner's serial number engraved on it, these can be quite small and difficult to read. Recognizing that each facility seems to use a different ID, a cylinder can have several different numbers recorded on it by means of metal plates, sticky labels, paint or even marker pen as it travels among facilities around the world. The idea of monitoring movements of UF{sub 6} cylinders throughout the global uranium fuel cycle has become a significant issue among industrial and safeguarding stakeholders. Global monitoring would provide the locations, movements, and uses of cylinders in commercial nuclear transport around the world, improving the efficiency of industrial operations while increasing the assurance that growing nuclear commerce does not result in the loss or misuse of cylinders. It should be noted that a unique ID (UID) attached to a cylinder in a verifiable manner is necessary for safeguarding needs and ensuring positive ID, but not sufficient for an effective global monitoring system. Modern technologies for tracking and inventory control can pair the UID with sensors and secure data storage for content information and complete continuity of knowledge over the cylinder. This paper will describe how the next steps in development of an action plan for employing a global UF{sub 6} cylinder monitoring network could be cultivated using four primary UID functions - identification, tracking, controlling, and accounting.

  13. Two interacting cylinders in cross flow.

    PubMed

    Alam, Md Mahbub; Meyer, J P

    2011-11-01

    Cylindrical structures in a group are frequently seen on land and in the ocean. Mutual flow interaction between the structures makes the wake very excited or tranquil depending on the spacing between the structures. The excited wake-enhancing forces in some cases cause a catastrophic failure of the structures. This paper presents results of an experimental investigation of Strouhal number (St), time-mean, and fluctuating forces on, and flow structures around, two identical circular cylinders at stagger angle α = 0°-180° and gap-spacing ratio T/D=0.1-5, where T is the gap width between the cylinders, and D is the diameter of a cylinder. While forces were measured using a load cell, St was from spectral analysis of fluctuating pressures measured on the side surfaces of the cylinders. A flow visualization test was conducted to observe flow structures around the cylinders. Based on forces, St, and flow structures, 19 distinct flow categories in the ranges of α and T/D investigated are observed, including one quadristable flow, three kinds of tristable flows, and four kinds of bistable flows. The quadristable, tristable, and bistable flows ensue from instabilities of the gap flow, shear layers, vortices, separation bubbles, and wakes, engendering a strong jump or drop in forces and St of the cylinders. The two cylinders interact with each other in six different mechanisms, namely interaction between boundary layer and cylinder, shear layer or wake and cylinder, shear layer and shear layer, vortex and cylinder, vortex and shear layer, and vortex and vortex. While the interaction between vortex and cylinder results in a very high fluctuating drag, that between vortex and shear layer results in a high fluctuating lift. On the other hand, the interaction between shear layer or wake and cylinder weakens mean and fluctuating forces and flow unsteadiness. A mutual discussion of forces, St, and flow structures is presented in this paper.

  14. Hydrodynamic Force on a Cylinder Oscillating at Low Frequency

    NASA Technical Reports Server (NTRS)

    Berg, Robert F.; Yao, Minwu; Panzarella, Charles H.

    2007-01-01

    The hydrodynamic force on a cylinder oscillating transversely to its axis is a nonlinear function of the displacement amplitude x0. We report measurements and numerical calculations of the force at frequencies low enough that delta > R, where delta is the viscous penetration length and R is the cylinder radius. For small amplitudes, the numerically calculated Fourier transform of the force per unit length, F(sub small), agrees with Stokes' analytical calculation. For larger amplitudes, the force per unit length found by both calculation and measurement is F = F(sub small)C (x(sub 0)/delta,R/delta). The complex function C depends only weakly on R/delta, indicating that x0/delta is more appropriate as a scaling variable than the Keulegan-Carpenter number KC = pi*x(sub 0)/R. The measurements used a torsion oscillator driven at frequencies from 1 to 12 Hz while immersed in dense xenon. The oscillator comprised cylinders with an effective radius of R = 13.4 micron and oscillation amplitudes as large as x(sub 0)/delta = 4 (corresponding to KC as large as 71). The calculations used similar conditions except that the amplitudes were as large as x0/delta = 28.

  15. Cylinder valve packing nut studies

    SciTech Connect

    Blue, S.C.

    1991-12-31

    The design, manufacture, and use of cylinder valve packing nuts have been studied to improve their resistance to failure from stress corrosion cracking. Stress frozen photoelastic models have been analyzed to measure the stress concentrations at observed points of failure. The load effects induced by assembly torque and thermal expansion of stem packing were observed by strain gaging nuts. The effects of finishing operations and heat treatment were studied by the strain gage hole boring and X-ray methods. Modifications of manufacturing and operation practices are reducing the frequency of stress corrosion failures.

  16. Transonic Flow Past Cone Cylinders

    NASA Technical Reports Server (NTRS)

    Solomon, George E

    1955-01-01

    Experimental results are presented for transonic flow post cone-cylinder, axially symmetric bodies. The drag coefficient and surface Mach number are studied as the free-stream Mach number is varied and, wherever possible, the experimental results are compared with theoretical predictions. Interferometric results for several typical flow configurations are shown and an example of shock-free supersonic-to-subsonic compression is experimentally demonstrated. The theoretical problem of transonic flow past finite cones is discussed briefly and an approximate solution of the axially symmetric transonic equations, valid for a semi-infinite cone, is presented.

  17. Fire exposure of empty 30B cylinders

    SciTech Connect

    Ziehlke, K.T.

    1991-12-31

    Cylinders for UF{sub 6} handling, transport, and storage are designed and built as unfired pressure vessels under ASME Boiler and Pressure Vessel Code criteria and standards. They are normally filled and emptied while UF{sub 6} is in its liquid phase. Transport cylinders such as the Model 30B are designed for service at 200 psi and 250{degrees}F, to sustain the process conditions which prevail during filling or emptying operations. While in transport, however, at ambient temperature the UF{sub 6} is solid, and the cylinder interior is well below atmospheric pressure. When the cylinders contain isotopically enriched product (above 1.0 percent U-235), they are transported in protective overpacks which function to guard the cylinders and their contents against thermal or mechanical damage in the event of possible transport accidents. Two bare Model 30B cylinders were accidentally exposed to a storage warehouse fire in which a considerable amount of damage was sustained by stored materials and the building structure, as well as by the cylinder valves and valve protectors. The cylinders were about six years old, and had been cleaned, inspected, hydrotested, and re-certified for service, but were still empty at the time of the fire. The privately-owned cylinders were transferred to DOE for testing and evaluation of the fire damage.

  18. Overseas shipments of 48Y cylinders

    SciTech Connect

    Tanaka, R.T.; Furlan, A.S.

    1991-12-31

    This paper describes experiences with two incidents of overseas shipments of uranium hexafluoride (UF{sub 6}) cylinders. The first incident involved nine empty UF{sub 6} cylinders in enclosed sea containers. Three UF{sub 6} cylinders broke free from their tie-downs and damaged and contaminated several sea containers. This paper describes briefly how decontamination was carried out. The second incident involved a shipment of 14 full UF{sub 6} cylinders. Although the incident did not cause an accident, the potential hazard was significant. The investigation of the cause of the near accident is recounted. Recommendations to alleviate future similar incidents for both cases are presented.

  19. Vortex motion behind a circular cylinder

    NASA Technical Reports Server (NTRS)

    Foeppl, L.

    1983-01-01

    Vortex motion behind a circular cylinder moving through water is discussed. It is shown that a pair of vortices form behind a moving cylinder and that their centers will move along a predictable curve. This curve represents an equilibrium condition which, however, is subject to perturbation. The stability of the vortex pair is investigated. Movement of the vortex pair away from the cylinder is calculated as an explanation of the resistance of the cylinder. Finally, the principles elaborated are applied to the flow around a flat plate.

  20. Cylinder head cover structure for a V-type engine

    SciTech Connect

    Okada, M.; Nishida, M.; Hokazono, K.

    1988-11-15

    This patent describes a cylinder head cover structure for a cylinder engine having first and second cylinder heads for forming first and second cylinder banks, each cylinder head being provided, in an inner side wall thereof, with intake ports each communicating with a cylinder formed in the cylinder bank, at least one camshaft provided in each cylinder bank above intake and exhaust valves to drive the valves in synchronization with rotation of the engine and supported for rotation by a plurality of bearings, discrete intake passages each of which is connected to one of the intake ports of one of the cylinder banks and extends above the other cylinder bank, and cylinder head covers mounted on the respective cylinder heads, characterized in that recessed portions are formed in each of the cylinder head covers at corresponding portions of the camshaft and respective the discrete intake passages extend through corresponding ones of the recessed portions.

  1. Internal combustion engine cylinder-to-cylinder balancing with balanced air-fuel ratios

    DOEpatents

    Harris, Ralph E.; Bourn, Gary D.; Smalley, Anthony J.

    2006-01-03

    A method of balancing combustion among cylinders of an internal combustion engine. For each cylinder, a normalized peak firing pressure is calculated as the ratio of its peak firing pressure to its combustion pressure. Each cylinder's normalized peak firing pressure is compared to a target value for normalized peak firing pressure. The fuel flow is adjusted to any cylinder whose normalized peak firing pressure is not substantially equal to the target value.

  2. Techno-economic projections for advanced small solar thermal electric power plants to years 1990-2000

    NASA Technical Reports Server (NTRS)

    Fujita, T.; Manvi, R.; Roschke, E. J.; El-Gabalawi, N.; Herrera, G.; Kuo, T. J.; Chen, K. H.

    1979-01-01

    Advanced technologies applicable to solar thermal electric power systems in the 1990-200 time-frame are delineated for power applications that fulfill a wide spectrum of small power needs with primary emphasis on power ratings less than 10MWe. Projections of power system characteristics (energy and capital costs as a function of capacity factor) are made based on development of identified promising technologies and are used as the basis for comparing technology development options and combinations of these options to determine developmental directions offering potential for significant improvements. Stirling engines, Brayton/Rankine combined cycles and storage/transport concepts encompassing liquid metals, and reversible-reaction chemical systems are considered for two-axis tracking systems such as the central receiver or power tower concept and distributed parabolic dish receivers which can provide efficient low-cost solar energy collection while achieving high temperatures for efficient energy conversion. Pursuit of advanced technology across a broad front can result in post-1985 solar thermal systems having the potential of approaching the goal of competitiveness with conventional power systems.

  3. Operation Sun Beam, Shot Small Boy. Project Officer's report - Project 6. 9. Correlation of present and previous electric-field measurements

    SciTech Connect

    Reno; Fowles, H.M.

    1985-09-01

    On most previous nuclear detonations, signatures and quantitative measurements of the electric-field signals associated with the detonations was obtained at distances such that normal radiation field characteristics apply. On Small Boy, measurements were made from stations located much closer in, such as to be inside, on the boundary of and just outside the limits of the ionized sphere created by the nuclear burst. The electric-field characteristics in these regions were unknown. In the hope of providing continuity from the region of the unknown into the reasonably well-understood region of the radiation field, this project was requested to make the typical radiation-field type of measurement that had been made on previous detonations. This report covers the signature characteristics and quantitative measurements of the electric-field signal from Small Boy as seen from outside the immediate region of theoretical generating mechanism.

  4. Influence of the exhaust system on performance of a 4-cylinder supercharged engine

    SciTech Connect

    Trenc, F.; Bizjan, F.; Hribernik, A.

    1998-10-01

    Twin entry radial turbines are mostly used to drive compressors of small and medium size 6-cylinder diesel engines where the available energy of the undisturbed exhaust pulses can be efficiently used to drive the turbine of a turbocharger. Three selected cylinders feed two separated manifold branches and two turbine inlets and prevent negative interaction of pressure waves and its influence on the scavenging process of the individual cylinders. In the case of a four-stroke, 4-cylinder engine, two selected cylinders, directed by the firing order, can be connected to one (of the two) separated manifold branches that feeds one turbine entry. Good utilization of the pressure pulse energy, together with typically longer periods of reduced exhaust flow can lead to good overall efficiency of the two-pulse system. Sometimes this system can be superior to the single manifold system with four cylinders connected to one single-entry turbine. The paper describes advantages and disadvantages of the above described exhaust systems applied to a turbocharged and aftercooled 4-cylinder Diesel engine. Comparisons supported by the analyses of the numerical and experimental results are also given in the presented paper.

  5. Sub-grid drag models for horizontal cylinder arrays immersed in gas-particle multiphase flows

    SciTech Connect

    Sarkar, Avik; Sun, Xin; Sundaresan, Sankaran

    2013-09-08

    Immersed cylindrical tube arrays often are used as heat exchangers in gas-particle fluidized beds. In multiphase computational fluid dynamics (CFD) simulations of large fluidized beds, explicit resolution of small cylinders is computationally infeasible. Instead, the cylinder array may be viewed as an effective porous medium in coarse-grid simulations. The cylinders' influence on the suspension as a whole, manifested as an effective drag force, and on the relative motion between gas and particles, manifested as a correction to the gas-particle drag, must be modeled via suitable sub-grid constitutive relationships. In this work, highly resolved unit-cell simulations of flow around an array of horizontal cylinders, arranged in a staggered configuration, are filtered to construct sub-grid, or `filtered', drag models, which can be implemented in coarse-grid simulations. The force on the suspension exerted by the cylinders is comprised of, as expected, a buoyancy contribution, and a kinetic component analogous to fluid drag on a single cylinder. Furthermore, the introduction of tubes also is found to enhance segregation at the scale of the cylinder size, which, in turn, leads to a reduction in the filtered gas-particle drag.

  6. PPM mixtures of formaldehyde in gas cylinders: Stability and analysis

    SciTech Connect

    Wong, K.C.; Miller, S.B.; Patterson, L.M.

    1999-07-01

    Scott Specialty Gases has been successful in producing stable calibration gases of formaldehyde at low concentration. Critical to this success has been the development of a treatment process for high pressure aluminum cylinders. Formaldehyde cylinders having concentrations of 20ppm and 4ppm were found to show only small decline in concentrations over a period of approximately 12 months. Since no NIST traceable formaldehyde standards (or Standard Reference Material) are available, all Scott's formaldehyde cylinders were originally certified by traditional impinger method. This method involves an extremely tedious purification procedure for 2,4-dinitrophenylhydrazine (2,4-DNPH). A modified version of the impinger method has been developed and does not require extensive reagent purification for formaldehyde analysis. Extremely low formaldehyde blanks have been obtained with the modified method. The HPLC conditions in the original method were used for chromatographic separations. The modified method results in a lower analytical uncertainty for the formaldehyde standard mixtures. Consequently, it is possible to discern small differences between analytical results that are important for stability study.

  7. Vibrations and stresses in layered anisotropic cylinders

    NASA Technical Reports Server (NTRS)

    Mulholland, G. P.; Gupta, B. P.

    1976-01-01

    An equation describing the radial displacement in a k layered anisotropic cylinder was obtained. The cylinders are initially unstressed but are subjected to either a time dependent normal stress or a displacement at the external boundaries of the laminate. The solution is obtained by utilizing the Vodicka orthogonalization technique. Numerical examples are given to illustrate the procedure.

  8. Topping pressure for gas-storage cylinders

    NASA Technical Reports Server (NTRS)

    Haben, R. L.

    1979-01-01

    With charts derived from gas-storage system model, required topping pressure can be determined from initial cylinder pressure and temperature of gas entering cylinder. Charts are available for hydrogen and oxygen and can be developed for other important industrial gases as well.

  9. Positive displacement cylinder measures corrosive liquid volume

    NASA Technical Reports Server (NTRS)

    Mariman, R. A.; Vendl, C. J.

    1966-01-01

    Positive displacement cylinder accurately measures volumetric flow rates of corrosive liquids. The cylinder is compatible with corrosive liquids and handles flow rates from zero to 75 gpm at pressures to 900 psig with an accuracy of 0.25 per cent.

  10. Efficient visual grasping alignment for cylinders

    NASA Technical Reports Server (NTRS)

    Nicewarner, Keith E.; Kelley, Robert B.

    1991-01-01

    Monocular information from a gripper-mounted camera is used to servo the robot gripper to grasp a cylinder. The fundamental concept for rapid pose estimation is to reduce the amount of information that needs to be processed during each vision update interval. The grasping procedure is divided into four phases: learn, recognition, alignment, and approach. In the learn phase, a cylinder is placed in the gripper and the pose estimate is stored and later used as the servo target. This is performed once as a calibration step. The recognition phase verifies the presence of a cylinder in the camera field of view. An initial pose estimate is computed and uncluttered scan regions are selected. The radius of the cylinder is estimated by moving the robot a fixed distance toward the cylinder and observing the change in the image. The alignment phase processes only the scan regions obtained previously. Rapid pose estimates are used to align the robot with the cylinder at a fixed distance from it. The relative motion of the cylinder is used to generate an extrapolated pose-based trajectory for the robot controller. The approach phase guides the robot gripper to a grasping position. The cylinder can be grasped with a minimal reaction force and torque when only rough global pose information is initially available.

  11. Extinction properties of infinitely long graphite cylinders

    NASA Astrophysics Data System (ADS)

    Jazbi, B.; Hoyle, F.; Wickramasinghe, N. C.

    1991-12-01

    The extinction efficiencies of randomly oriented infinite graphite cylinders, including hollow cylinders are calculated, using the rigorous Kerker-Matijevic formulas. The peak in the mid-UV extinction varies in wavelength with particle radius and cavity size in a way that makes such particles of limited interest as models of interstellar grains.

  12. Stabilization of flow past a rounded cylinder

    NASA Astrophysics Data System (ADS)

    Samtaney, Ravi; Zhang, Wei

    2016-11-01

    We perform global linear stability analysis on low-Re flow past a rounded cylinder. The cylinder corners are rounded with a radius R, normalized as R+ = R / D where D is the cylinder diameter, and its effect on the flow stability characteristics is investigated. We compute the critical Reynolds number (Recr) for the onset of first instability, and quantify the perturbation growth rate for the super-critical flows. It is found that the flow can be stabilized by partially rounding the cylinder. Compared with the square and circular cylinders, the partially rounded cylinder has a higher Recr , attaining a maximum at around R+ = 0 . 30 , and the perturbation growth rate of the super-critical flows is reduced for Re <= 100 . We perform sensitivity analysis to explore the source of the stabilization. The growth rate sensitivity to base flow modification has two different spatial structures: the growth rate is sensitive to the wake backflow in a large region for square-like cylinders (R+ -> 0 . 00), while only the near-wake backflow is crucial for circular-like cylinders (R+ -> 0 . 50). The stability analysis results are also verified with those of the direct simulations and very good agreement is achieved. Supported by the KAUST Office of Competitive Research Funds under Award No. URF/1/1394-01. The supercomputer Shaheen at KAUST was utilized for the simulations.

  13. Aeroacoustic Simulations of Tandem Cylinders with Subcritical Spacing

    NASA Technical Reports Server (NTRS)

    Lockard, David P.; Choudhari, Meelan M.; Khorrami, Mehdi R.; Neuhart, Dan H.; Hutcheson, Florence V.; Brooks, Thomas F.; Stead, Daniel J.

    2008-01-01

    Tandem cylinders are being studied because they model a variety of component level interactions of landing gear. The present effort is directed at the case of two identical cylinders with their centroids separated in the streamwise direction by 1.435 diameters. Experiments in the Basic Aerodynamic Research Tunnel and Quiet Flow Facility at NASA Langley Research Center have provided an extensive experimental database of the nearfield flow and radiated noise. The measurements were conducted at a Mach number of 0.1285 and Reynolds number of 1.66x10(exp 5) based on the cylinder diameter. A trip was used on the upstream cylinder to insure a fully turbulent flow separation and, hence, to simulate a major aspect of high Reynolds number flow. The parallel computational effort uses the three-dimensional Navier-Stokes solver CFL3D with a hybrid, zonal turbulence model that turns off the turbulence production term everywhere except in a narrow ring surrounding solid surfaces. The experiments exhibited an asymmetry in the surface pressure that was persistent despite attempts to eliminate it through small changes in the configuration. To model the asymmetry, the simulations were run with the cylinder configuration at a nonzero but small angle of attack. The computed results and experiments are in general agreement that vortex shedding for the spacing studied herein is weak relative to that observed at supercritical spacings. Although the shedding was subdued in the simulations, it was still more prominent than in the experiments. Overall, the simulation comparisons with measured near-field data and the radiated acoustics are reasonable, especially if one is concerned with capturing the trends relative to larger cylinder spacings. However, the flow details of the 1.435 diameter spacing have not been captured in full even though very fine grid computations have been performed. Some of the discrepancy may be associated with the simulation s inexact representation of the

  14. 9. General view of engine between cylinders with high pressure ...

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

    9. General view of engine between cylinders with high pressure cylinder on left and low pressure cylinder on right. - Carnegie Steel-Ohio Works, Steam Engines, 912 Salt Springs Road, Youngstown, Mahoning County, OH

  15. A new steel for single cylinder steam turbine rotors

    SciTech Connect

    Yamada, M.; Tsuda, Y.; Tanaka, Y.; Ikeda, Y.

    1996-12-31

    A new steel, 2.25%Cr1.7%NiMoVNbW steel has been developed for the high pressure (HP)-low pressure (LP) single cylinder steam turbine rotor in combined power plants and medium/small rating thermal power plants. This steel has good creep rupture strength equivalent to that of 1%CrMoV steel which has been used as HP rotor fogings and excellent toughness and proof stress considerably superior to the conventional HP-LP single cylinder rotor steels. This paper includes the following contents: The optimization of chemical composition and heat treatment condition; the production and evaluation of a 70 tons trial rotor forging by the application of VCD (Vacuum Carbon Deoxidation) process; the production and evaluation of a 43 tons trial ingot by the application of ESR (Electroslag Remelting) ingot process; and the production and evaluation of rotor forgings for the commercial power plant.

  16. Spin-up in a rectangular cylinder

    NASA Astrophysics Data System (ADS)

    Stewart, Dawn L.

    1993-12-01

    We examined the spin-up from rest of water in a rectangular cylinder. The presence of corners in the cylinder causes the formation of eddies. We found that the number of eddies, as well as eddy size, position, and rotation rate were dependent on the aspect ratio of the cylinder, the depth of the fluid, and the final angular velocity of the cylinder. Two time scales were found to be important in this experiment: the traditional Ekman number based on depth, which defines the time scale required for spin-up and an additional Ekman number based on the cylinder length which provides some information about the evolution of the fluid pathlines in route to spin-up. This second Eckman number appears to provide an explanation for both the agreement and disagreement of the experimental results herein and previously published results.

  17. Tests on Stiffened Circular Cylinders

    NASA Technical Reports Server (NTRS)

    Holt, Marshall

    1941-01-01

    Compressive tests were made of two series of stiffened circular cylindrical shells under axial load. All the shells were 16 inches in diameter by 24 inches in length and were made of aluminum-alloy sheet curved to the proper radius and welded with one longitudinal weld. The ratios of diameter to thickness of shell wall in the two series of specimens were 258 and 572. Strains were measured with Huggenberger tensometers at a number of gage lines on the stiffeners and shell. The results of these tests indicate that a spacing of circumferential stiffeners equal to 0.67 times the radius is too great to strengthen the shell wall appreciably. The results are not inclusive enough to show the optimum in stiffeners. Plain cylinders without stiffeners developed ultimate strengths approximately half as great as the buckling strengths computed by the equation resulting from the classical theory and slightly greater than those computed by Donnell's large deflection theory.

  18. Thermal and catalytic pyrolysis of a mixture of plastics from small waste electrical and electronic equipment (WEEE).

    PubMed

    Santella, Chiara; Cafiero, Lorenzo; De Angelis, Doina; La Marca, Floriana; Tuffi, Riccardo; Vecchio Ciprioti, Stefano

    2016-08-01

    Pyrolysis seems a promising route for recycling of heterogeneous, contaminated and additives containing plastics from waste electrical and electronic equipment (WEEE). This study deals with the thermal and catalytic pyrolysis of a synthetic mixture containing real waste plastics, representative of polymers contained in small WEEE. Two zeolite-based catalysts were used at 400°C: HUSY and HZSM-5 with a high silica content, while three different temperatures were adopted for the thermal cracking: 400, 600 and 800°C. The mass balance showed that the oil produced by pyrolysis is always the main product regardless the process conditions selected, with yields ranging from 83% to 93%. A higher yield was obtained when pyrolysis was carried out with HZSM-5 at 400°C and without catalysts, but at 600 and 800°C. Formation of a significant amount of solid residue (about 13%) is observed using HUSY. The oily liquid product of pyrolysis, analysed by GC-MS and GC-FID, as well as by elemental analysis and for energy content, appeared lighter, less viscous and with a higher concentration of monoaromatics under catalytic condition, if compared to the liquid product derived from thermal degradation at the same temperature. HZSM-5 led to the production of a high yield of styrene (17.5%), while HUSY favoured the formation of ethylbenzene (15%). Energy released by combustion of the oil was around 39MJ/kg, thus suggesting the possibility to exploit it as a fuel, if the recovery of chemical compounds could not be realised. Elemental and proximate analysis of char and GC-TCD analysis of the gas were also performed. Finally, it was estimated to what extent these two products, showing a relevant ability to release energy, could fulfil the energy demand requested in pyrolysis.

  19. Aerodynamic modification to a circular cylinder to enhance the piezoelectric wind energy harvesting

    NASA Astrophysics Data System (ADS)

    Hu, Gang; Tse, K. T.; Kwok, K. C. S.; Song, Jie; Lyu, Yuan

    2016-11-01

    This study aims to expand the aeroelastic unstable range of a circular cylinder for improving the efficiency of a vortex-induced vibration (VIV)-based wind energy harvester. The kinetic energy of the harvester is provided by flow-induced vibration of a circular cylinder. Two small-diameter cylindrical rods were attached on two sides of the circular cylinder parallel to the cylinder axis and symmetrical to the stagnation line at a series of circumferential locations. This was inspired by rain-wind-induced vibrations of stay-cables of cable-stayed bridges. It was found that attaching two small-diameter cylindrical rods at the circumferential location θ = 60° significantly expands the aeroelastic unstable range for the circular cylinder. The wind energy harvester with this configuration harnesses the wind energy beyond the VIV onset wind speed and is sustained over the range of wind speed. Therefore, this configuration possesses a dramatic superiority over a plain circular cylinder as the kinetic source of a wind energy harvester.

  20. Experimental study on free convection of sodium in a long cylinder

    NASA Astrophysics Data System (ADS)

    Kolesnichenko, I. V.; Mamykin, A. D.; Pavlinov, A. M.; Pakholkov, V. V.; Rogozhkin, S. A.; Frick, P. G.; Khalilov, R. I.; Shepelev, S. F.

    2015-06-01

    The operation experience of sodium fast reactor shows that during design-basis validation of pipelines and equipment it is necessary to take into account the sodium free convection in the enclosures. The paper presents the results of experimental study of free convection of liquid sodium in a long thermo-insulated cylinder with the end heat supply and removal. The sodium-filled cylinder diameter is 168 mm, length is 850 mm. Three experiments for horizontal, inclined (at 45° to a vertical line) and vertical position of the cylinder were compared in detail. The Rayleigh number (based on cylinder diameter) is approximately same for three experiments and is equal to 5 × 106. The structure of large-scale and small-scale flows was analyzed. Nusselt number estimations being the intensity measure of heat transfer in case of free convection were obtained. A relationship between the flow structure and the Nusselt number is revealed.

  1. Noncontact gears. II. Casimir torque between concentric corrugated cylinders for the scalar case

    SciTech Connect

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

    2008-09-15

    The Casimir interaction between two concentric corrugated cylinders provides the mechanism for noncontact gears. To this end, we calculate the Casimir torque between two such cylinders, described by {delta}-potentials, which interact through a scalar field. We derive analytic expressions for the Casimir torque for the case when the corrugation amplitudes are small in comparison to the corrugation wavelengths. We derive explicit results for the Dirichlet case, and exact results for the weak coupling limit, in the leading order. The results for the corrugated cylinders approach the corresponding expressions for the case of corrugated parallel plates in the limit of large radii of cylinders (relative to the difference in their radii) while keeping the corrugation wavelength fixed.

  2. Noncontact gears. II. Casimir torque between concentric corrugated cylinders for the scalar case

    NASA Astrophysics Data System (ADS)

    Cavero-Peláez, Inés; Milton, Kimball A.; Parashar, Prachi; Shajesh, K. V.

    2008-09-01

    The Casimir interaction between two concentric corrugated cylinders provides the mechanism for noncontact gears. To this end, we calculate the Casimir torque between two such cylinders, described by δ-potentials, which interact through a scalar field. We derive analytic expressions for the Casimir torque for the case when the corrugation amplitudes are small in comparison to the corrugation wavelengths. We derive explicit results for the Dirichlet case, and exact results for the weak coupling limit, in the leading order. The results for the corrugated cylinders approach the corresponding expressions for the case of corrugated parallel plates in the limit of large radii of cylinders (relative to the difference in their radii) while keeping the corrugation wavelength fixed.

  3. The quest to be "modern": The adoption of electric light, heat, and power technology in small-town America, 1883-1929

    NASA Astrophysics Data System (ADS)

    Hellrigel, Mary Ann

    This dissertation is a social, business, and technological history of electrification in the United States. It examines the origins of the electric utility industry, the development of light, heat and power technology, the marketing of electric service, and the adoption of electricity and domestic appliances in the late nineteenth and early twentieth centuries in two communities: Harrisburg and West Chester, Pennsylvania. Beginning in the 1880s, manufactured gas and electric utilities waged an intense and lengthy battle for the urban energy marketplace. Many villages, small towns and big cities had multiple gas and electric companies, driving technological change as they worked to increase reliability, lower costs, and improve lamps, lighting fixtures, and appliances. Producers as well as consumers grappled with these new sources of energy, looking for profitable and practical ways to incorporate them into everyday life. Gas and utility executives, locked in head-to-head competition, realized that marketing their invisible product was an uncertain process. Utilities redefined the concepts of "tradition" and "modernity" to attract investors and offer appliances and installation in addition to selling energy. Upper and middle class households seeking a modern comfortable home could use gas or electricity (and often both), while working classes made do with kerosene, coal and wood. Mixed technologies, based on consumer preference, access, product availability, price, and service greatly influenced the creation of "modern" America. Initially, Pennsylvania law mandated local energy systems-electricity and gas had to be consumed within the same town. Only in the early twentieth century were these laws amended to permit inter-connections, allowing merger and consolidation of utilities to serve a wider geographic area. By the 1910s, law, technology, and capital made it possible to abandon local central stations. In only a few decades, the industry shifted from locally

  4. Spanwise plumes in wakes behind heated cylinder

    NASA Astrophysics Data System (ADS)

    Kumar, S. Ajith; Lal, S. Anil; Sameen, A.

    2013-11-01

    3D wake transition in flow past cylinder is interesting theoretically and industrially. A three dimensional Finite volume computation has been performed on an incompressible flow past heated cylinder to understand the wake behavior behind the cylinder, under the Boussinesq assumption. We study the heat transfer characteristics and the coherent structures behind the cylinder at different Prandtl numbers. In forced convection, the 3D transition occurs above Reynolds number, Re = 180-190 (Re is based on the cylinder diameter). However, the present 3D computational analyses show that in mixed convection, the so called ``mode-E'' instability (3D transition of wake behind the cylinder caused by the heating of the cylinder) happens at a much lower Reynolds number. The co-existence of mushroom like coherent structures called the plumes along with the shed vortices is observed for a range of heating conditions. These plumes originates from the core of the upper vortex rows at a definite span wise wavelengths. The dependence of Prandtl number on the span wise wavenumber of these plumes is also analyzed.

  5. Gas cylinder release rate testing and analysis

    NASA Astrophysics Data System (ADS)

    Despres, Joseph; Sweeney, Joseph; Yedave, Sharad; Chambers, Barry

    2012-11-01

    There are varying cylinder technologies employed for the storage of gases, each resulting in a potentially different hazard level to the surroundings in the event of a gas release. Subatmospheric Gas delivery Systems Type I (SAGS I) store and deliver gases subatmospherically, while Subatmospheric Gas delivery Systems Type II (SAGS II) deliver gases subatmospherically, but store them at high pressure. Standard high pressure gas cylinders store and deliver their contents at high pressure. Due to the differences in these cylinder technologies, release rates in the event of a leak or internal component failure, can vary significantly. This paper details the experimental and theoretical results of different Arsine (AsH3) gas cylinder release scenarios. For the SAGS II experimental analysis, Fourier Transform Infrared Spectroscopy (FTIR) was used to determine the spatial concentration profiles when a surrogate gas, CF4, was released via a simulated leak within an ion implanter. Various SAGS I and SAGS II cylinder types and failure modes were tested. Additionally, theoretical analysis was performed to support an understanding of the different potential AsH3 leak rates. The results of this work show that the effects of a leak from the various cylinder types can be quite different, with the concentrations resulting from cylinders containing high pressure gas often being in excess of IDLH levels.

  6. Habitat Demonstration Unit (HDU) Vertical Cylinder Habitat

    NASA Technical Reports Server (NTRS)

    Howe, Alan; Kennedy, Kriss J.; Gill, Tracy R.; Tri, Terry O.; Toups, Larry; Howard, Robert I.; Spexarth, Gary R.; Cavanaugh, Stephen; Langford, William M.; Dorsey, John T.

    2014-01-01

    NASA's Constellation Architecture Team defined an outpost scenario optimized for intensive mobility that uses small, highly mobile pressurized rovers supported by portable habitat modules that can be carried between locations of interest on the lunar surface. A compact vertical cylinder characterizes the habitat concept, where the large diameter maximizes usable flat floor area optimized for a gravity environment and allows for efficient internal layout. The module was sized to fit into payload fairings for the Constellation Ares V launch vehicle, and optimized for surface transport carried by the All-Terrain Hex-Limbed Extra-Terrestrial Explorer (ATHLETE) mobility system. Launch and other loads are carried through the barrel to a top and bottom truss that interfaces with a structural support unit (SSU). The SSU contains self-leveling feet and docking interfaces for Tri-ATHLETE grasping and heavy lift. A pressurized module needed to be created that was appropriate for the lunar environment, could be easily relocated to new locations, and could be docked together in multiples for expanding pressurized volume in a lunar outpost. It was determined that horizontally oriented pressure vessels did not optimize floor area, which takes advantage of the gravity vector for full use. Hybrid hard-inflatable habitats added an unproven degree of complexity that may eventually be worked out. Other versions of vertically oriented pressure vessels were either too big, bulky, or did not optimize floor area. The purpose of the HDU vertical habitat module is to provide pressurized units that can be docked together in a modular way for lunar outpost pressurized volume expansion, and allow for other vehicles, rovers, and modules to be attached to the outpost to allow for IVA (intra-vehicular activity) transfer between them. The module is a vertically oriented cylinder with a large radius to allow for maximal floor area and use of volume. The modular, 5- m-diameter HDU vertical habitat

  7. Where Millimeter Wave Spectra are Sensitive to Small Electric Fields: High Rydberg States of Xenon and Their Hyperfine Structures

    NASA Astrophysics Data System (ADS)

    Schäfer, Martin; Raunhardt, Matthias; Merkt, Frédéric

    2009-06-01

    In the range 0-45 cm^{-1} below the ionization limit, the separation between adjacent electronic states (Rydberg states with principal quantum number n>50) of atoms and molecules is smaller than 2 cm^{-1}. In order to resolve the fine or hyperfine structure of these states, it is necessary to combine high-resolution vacuum ultraviolet (VUV) laser radiation, which is required to access the Rydberg states from the ground state, with millimeter wave radiation. Such double-resonance experiments have been used to study the hyperfine structure of high Rydberg states of ^{83}Kr, H_2 or D_2. Millimeter wave transitions (240-350 GHz) between nℓ (52≤ n≤64, ℓ≤3) Rydberg states of different xenon isotopes were detected by pulsed field ionization followed by mass-selective detection of the cations. Because of the high polarizability of high-n Rydberg states (∝ n^7, ˜10^4 MHz cm^{2} V^{-2} for n≈ 50), it is necessary to reduce the electric stray fields to values of the order of mV/cm (or less) in order to minimize the (quadratic) Stark shift of the millimeter wave transitions. Some p and d Rydberg states of Xe are nearly degenerate and efficiently mixed by small stray fields, making it possible to observe transitions forbidden by the Δℓ=±1 selection rule or transitions exhibiting a linear Stark effect, which is typical for the degenerate high-ℓ Rydberg states. Multichannel quantum defect theory (MQDT) was used to analyze the millimeter wave data and to determine the hyperfine structures of the ^2P_{3/2} ground electronic states of ^{129}Xe^+ and ^{131}Xe^+. C. Fabre, P. Goy, S. Haroche, J. Phys. B: Atom. Mol. Phys. 10, L183-189 (1977). F. Merkt, A. Osterwalder, Int. Rev. Phys. Chem. 21, 385-403 (2002). M. Schäfer, M. Andrist, H. Schmutz, F. Lewen, G. Winnewisser, F. Merkt, J. Phys. B: At. Mol. Opt. Phys. 39, 831-845 (2006) M. Schäfer, F. Merkt, Phys. Rev. A, 74, 062506 (2006). A. Osterwalder, A. Wüest, F. Merkt, Ch. Jungen, J. Chem. Phys., 121, 11810

  8. High-Frequency Normal Mode Propagation in Aluminum Cylinders

    USGS Publications Warehouse

    Lee, Myung W.; Waite, William F.

    2009-01-01

    Acoustic measurements made using compressional-wave (P-wave) and shear-wave (S-wave) transducers in aluminum cylinders reveal waveform features with high amplitudes and with velocities that depend on the feature's dominant frequency. In a given waveform, high-frequency features generally arrive earlier than low-frequency features, typical for normal mode propagation. To analyze these waveforms, the elastic equation is solved in a cylindrical coordinate system for the high-frequency case in which the acoustic wavelength is small compared to the cylinder geometry, and the surrounding medium is air. Dispersive P- and S-wave normal mode propagations are predicted to exist, but owing to complex interference patterns inside a cylinder, the phase and group velocities are not smooth functions of frequency. To assess the normal mode group velocities and relative amplitudes, approximate dispersion relations are derived using Bessel functions. The utility of the normal mode theory and approximations from a theoretical and experimental standpoint are demonstrated by showing how the sequence of P- and S-wave normal mode arrivals can vary between samples of different size, and how fundamental normal modes can be mistaken for the faster, but significantly smaller amplitude, P- and S-body waves from which P- and S-wave speeds are calculated.

  9. Liquid-film coating on topographically patterned rotating cylinders

    NASA Astrophysics Data System (ADS)

    Li, Weihua; Carvalho, Marcio S.; Kumar, Satish

    2017-02-01

    The coating of discrete objects having surface topography is an important step in the manufacturing of a broad variety of products. To develop a fundamental understanding of this problem, we study liquid-film flow on rotating cylinders patterned with sinusoidal topographical features. The Stokes equations, augmented with a term accounting for centrifugal forces, are solved in a rotating reference frame using the Galerkin finite-element method (GFEM). A nonlinear evolution equation for the film thickness based on lubrication theory is also solved numerically and its predictions are compared to those from the GFEM calculations. When gravitational effects are negligible and the rotation rate is sufficiently low, liquid accumulates over the pattern troughs before merging to form multiple larger drops (located over troughs) whose number at steady state depends on the topography wavelength and rotation rate. When the rotation rate is sufficiently high, similar merging events occur, but liquid accumulates over the pattern crests at steady state. When gravitational forces become significant, it is possible to obtain a coating that closely conforms to the surface topography. The GFEM calculations are in agreement with predictions from the lubrication model provided the free-surface curvatures are sufficiently small. For sufficiently large pattern amplitude and film thickness, the GFEM calculations show that recirculation regions inside the troughs can appear and vanish as the cylinder rotates due to the variation of gravitational forces around the cylinder surface. This phenomenon, along with flow reversal over the crests, may strongly influence mixing, mass transport, and heat transport.

  10. Water-tunnel study of transition flow around circular cylinders

    NASA Technical Reports Server (NTRS)

    Almosnino, D.; Mcalister, K. W.

    1984-01-01

    The recently reported phenomenon of asymmetric flow separation from a circular cylinder in the critical Reynolds number regime has been confirmed in a water-tunnel experiment. For the first time, an attempt was made to visualize the wake of the cylinder during the transition from subcritical to critical flow and to correlate the visualizations with lift and drag measurements. The occurrence of a dominant asymmetric-flow state was quite repeatable, both when increasing and decreasing the Reynolds number, resulting in a mean lift coefficient of C sub L approx 1.2 and a shift in the angle of the wake by about 12 deg. A distinctive step change in the drag and shedding frequency was also found to occur. A hysteresis was confirmed to exist in this region as the Reynolds number was cycled over the transition range. Both boundaries of the asymmetry appear to be supercritical bifurcations in the flow. The asymmetry was normally steady in the mean; however, there were instances when the direction of the asymmetry reversed and remained so for the duration of the Reynolds number sweep through this transition region. A second asymmetry was observed at a higher Reynolds number; however, the mean lift coefficient was much lower, and the direction of the asymmetry was not observed to reverse. Introducing a small local disturbance into the boundary layer was found to prevent the critical asymmetry from developing along the entire span of the cylinder.

  11. Guidelines to assist rural electric cooperatives to fulfill the requirements of Sections 201 and 210 of PURPA for cogeneration and small power production

    SciTech Connect

    Not Available

    1981-02-01

    These guidelines were designed to assist National Rural Electric Cooperative Association staff and consultants involved in the implementation of Sections 201 and 210 of the Public Utilities Regulatory Policies Act (PURPA). The guidelines were structured to meet anticipated use as: a self-contained legal, technical and economic reference manual helpful in dealing with small power producers and cogenerators; a roadmap through some of the less obvious obstacles encountered by utilities interacting with small power producers and cogenerators; a starting point for those utilities who have not yet formulated specific policies and procedures, nor developed rates for purchasing power from small power producers and cogenerators; a discussion vehicle to highlight key issues and increase understanding in workshop presentations to rural electric cooperatives; and an evolutionary tool which can be updated to reflect changes in the law as they occur. The chapters in these Guidelines contain both summary information, such as compliance checklists, and detailed information, such as cost rate calculations, on regulatory requirements, operational considerations, and rate considerations. The appendices contain more specific material, e.g. rural electric cooperative sample policy statements. (LCL)

  12. Improved turbine cylinder bolting system

    SciTech Connect

    Gosling, M.C.

    1997-10-01

    This paper describes the design and development of a new cylinder bolting system to replace the main joint hardware for both combustion (and steam) turbine applications. The new bolts are designed to be hydraulically tensioned to the specified preload and utilize ultrasonic verification of elongation. The new bolting system uses a reduced number of components in each assembly and the individual components themselves are of a simplified design. The new hardware can be applied to new equipment without modification and retrofitted to customer-owned equipment as a direct replacement for existing joint hardware. The prototype, production, and field testing of this hardware, the installation tooling; and ultrasonic elongation measuring equipment are described. This testing has shown significant savings in assembly and disassembly cycle times even after prolonged exposure to turbine operating temperatures in a corrosive environment. The new design of bolting is now standard equipment for the CE251B11/B12 combustion turbine manufactured by Westinghouse P.G.B.U.

  13. Investigations of Flow past Spinning Cylinders

    NASA Astrophysics Data System (ADS)

    Mehmedagic, Igbal; Carlucci, Pasquale; Buckley, Liam; Carlucci, Donald; Aljallis, Elias; Thangam, Siva

    2013-11-01

    A subsonic wind tunnel is used to perform experiments on flow past spinning cylinders. The blunt cylinders are sting-mounted and oriented such that their axis of rotation is aligned with the mean flow. The experiments cover a Reynolds number range of up to 300000 and rotation numbers of up to 1.2 (based on cylinder diameter). The results for spinning cylinders with both rear-mounted and fore-mounted stings are presented. Computations are performed using a two-equation anisotropic turbulence model that is based on proper representation of the energy spectrum to capture rotation and curvature. The model performance is validated with benchmark experimental flows and implemented for analyzing the flow configuration used in the experimental study. Funded in part by U. S. Army, ARDEC.

  14. Experimental Investigations of Flow past Spinning Cylinders

    NASA Astrophysics Data System (ADS)

    Carlucci, Pasquale; Buckley, Liam; Mehmedagic, Igbal; Carlucci, Donald; Thangam, Siva

    2015-11-01

    Experimental investigations of flow past spinning cylinders is presented in the context of their application and relevance to flow past projectiles. A subsonic wind tunnel is used to perform experiments on flow past spinning cylinders that are sting-mounted and oriented such that their axis of rotation is aligned with the mean flow. The experiments cover a Reynolds number range of up to 300000 and rotation numbers of up to 2 (based on cylinder diameter). The experimental validation of the tunnel characteristics and the benchmarking of the flow field in the tunnel are described. The experimental results for spinning cylinders with both rear-mounted and fore-mounted stings are presented along with available computational and experimental findings. This work was funded in part by U. S. Army ARDEC.

  15. Heat transfer in geometrically similar cylinders

    NASA Technical Reports Server (NTRS)

    Riekert, P; Held, A

    1941-01-01

    The power and heat-stress conditions of geometrically similar engines are discussed. The advantages accruing from smaller cylinder dimensions are higher specific horsepower, lower weight per horsepower, lower piston temperature, and less frontal area, with reduced detonation tendency.

  16. Multi-cylinder hot gas engine

    DOEpatents

    Corey, John A.

    1985-01-01

    A multi-cylinder hot gas engine having an equal angle, V-shaped engine block in which two banks of parallel, equal length, equally sized cylinders are formed together with annular regenerator/cooler units surrounding each cylinder, and wherein the pistons are connected to a single crankshaft. The hot gas engine further includes an annular heater head disposed around a central circular combustor volume having a new balanced-flow hot-working-fluid manifold assembly that provides optimum balanced flow of the working fluid through the heater head working fluid passageways which are connected between each of the cylinders and their respective associated annular regenerator units. This balanced flow provides even heater head temperatures and, therefore, maximum average working fluid temperature for best operating efficiency with the use of a single crankshaft V-shaped engine block.

  17. Skyrmion on a three-cylinder

    NASA Astrophysics Data System (ADS)

    Bratek, Łukasz

    2008-07-01

    The class of static, spherically symmetric, and finite energy hedgehog solutions in the SU(2) Skyrme model is examined on a metric three-cylinder. The exact analytic shape function of the 1-Skyrmion is found. It can be expressed via elliptic integrals. Its energy is calculated, and its stability with respect to radial and spherically symmetric deformations is analyzed. No other topologically nontrivial solutions belonging to this class are possible on the three-cylinder.

  18. Dynamic Fracture Simulations of Explosively Loaded Cylinders

    SciTech Connect

    Arthur, Carly W.; Goto, D. M.

    2015-11-30

    This report documents the modeling results of high explosive experiments investigating dynamic fracture of steel (AerMet® 100 alloy) cylinders. The experiments were conducted at Lawrence Livermore National Laboratory (LLNL) during 2007 to 2008 [10]. A principal objective of this study was to gain an understanding of dynamic material failure through the analysis of hydrodynamic computer code simulations. Two-dimensional and three-dimensional computational cylinder models were analyzed using the ALE3D multi-physics computer code.

  19. Statistical analyses of a screen cylinder wake

    NASA Astrophysics Data System (ADS)

    Mohd Azmi, Azlin; Zhou, Tongming; Zhou, Yu; Cheng, Liang

    2017-02-01

    The evolution of a screen cylinder wake was studied by analysing its statistical properties over a streamwise range of x/d={10-60}. The screen cylinder was made of a stainless steel screen mesh of 67% porosity. The experiments were conducted in a wind tunnel at a Reynolds number of 7000 using an X-probe. The results were compared with those obtained in the wake generated by a solid cylinder. It was observed that the evolution of the statistics in the wake of the screen cylinder was different from that of a solid cylinder, reflecting the differences in the formation of the organized large-scale vortices in both wakes. The streamwise evolution of the Reynolds stresses, energy spectra and cross-correlation coefficients indicated that there exists a critical location that differentiates the screen cylinder wake into two regions over the measured streamwise range. The formation of the fully formed large-scale vortices was delayed until this critical location. Comparison with existing results for screen strips showed that although the near-wake characteristics and the vortex formation mechanism were similar between the two wake generators, variation in the Strouhal frequencies was observed and the self-preservation states were non-universal, reconfirming the dependence of a wake on its initial condition.

  20. Evolution of Vortex Rings Exiting Inclined Cylinders

    NASA Astrophysics Data System (ADS)

    Longmire, E. K.; Webster, D. R.; Reetz, M.; Gefroh, D.

    1996-11-01

    Vortex rings initiated in cylinders with exit incline lengths of 0, D/4, and D/2 were investigated for Reynolds numbers up to 30,000. The fluid exiting each cylinder was visualized with an ionized bromothymol blue solution, and velocity fields were obtained with PIV. In each inclined case, vortex rings form at angles smaller than the cylinder incline angle. Entrainment of ambient fluid on the short side of the cylinder is much stronger than that on the long side. This results in a larger circulation about the short side of the ring and a greater propagation velocity on that side. The incline angle of the ring thus decreases as it moves downstream. Behind the ring core, an impulsive wave of entrained ambient fluid flows parallel to the cylinder exit plane. Some of this fluid is wrapped into the core, while the rest is ejected outward past the long cylinder edge. The vortex ring dynamics differ significantly from those observed in jets from inclined nozzles where neighboring rings are connected by straining zones, and ring incline angles increase with downstream distance.

  1. Externally pressurized porous cylinder for multiple surface aerosol generation and method of generation

    DOEpatents

    Apel, C.T.; Layman, L.R.; Gallimore, D.L.

    1988-05-10

    A nebulizer is described for generating aerosol having small droplet sizes and high efficiency at low sample introduction rates. The nebulizer has a cylindrical gas permeable active surface. A sleeve is disposed around the cylinder and gas is provided from the sleeve to the interior of the cylinder formed by the active surface. In operation, a liquid is provided to the inside of the gas permeable surface. The gas contacts the wetted surface and forms small bubbles which burst to form an aerosol. Those bubbles which are large are carried by momentum to another part of the cylinder where they are renebulized. This process continues until the entire sample is nebulized into aerosol sized droplets. 2 figs.

  2. Aspects of uranium chemistry pertaining to UF{sub 6} cylinder handling

    SciTech Connect

    Ritter, R.L.; Barber, E.J.

    1991-12-31

    Under normal conditions, the bulk of UF{sub 6} in storage cylinders will be in the solid state with an overpressure of gaseous UF{sub 6} well below one atmosphere. Corrosion of the interior of the cylinder will be very slow, with formation of a small amount of reduced fluoride, probably U{sub 2}F{sub 9}. The UO{sub 3}-HF-H{sub 2}O phase diagram indicates that reaction of any inleaking water vapor with the solid UF{sub 6} will generate the solid material [H{sub 3}O]{sub 2}(U(OH){sub 4}F{sub 4}) in equilibrium with an aqueous HF solution containing only small amounts of uranium. The corrosion of the steel cylinder by these materials may be enhanced over that observed with gaseous anhydrous UF{sub 6}.

  3. Plug-in Electric Vehicle Interactions with a Small Office Building: An Economic Analysis using DER-CAM

    SciTech Connect

    Momber, Ilan; Gomez, Tomás; Venkataramanan, Giri; Stadler, Michael; Beer, Sebastian; Lai, Judy; Marnay, Chris; Battaglia, Vincent

    2010-06-01

    It is generally believed that plug-in electric vehicles (PEVs) offer environmental and energy security advantages compared to conventional vehicles. Policies are stimulating electric transportation deployment, and PEV adoption may grow significantly. New technology and business models are being developed to organize the PEV interface and their interaction with the wider grid. This paper analyzes the PEVs' integration into a building's Energy Management System (EMS), differentiating between vehicle to macrogrid (V2M) and vehicle to microgrid (V2m) applications. This relationship is modeled by the Distributed Energy Resources Customer Adoption Model (DER-CAM), which finds optimal equipment combinations to meet microgrid requirements at minimum cost, carbon footprint, or other criteria. Results derive battery value to the building and the possibility of a contractual affiliation sharing the benefit. Under simple annual fixed payments and energy exchange agreements, vehicles are primarily used to avoid peak demand charges supplying cheaper off-peak electricity to the building during workdays.

  4. Scattering by an infinite homogenous anisotropic elliptic cylinder in terms of Mathieu functions and Fourier series.

    PubMed

    Mao, Shi-Chun; Wu, Zhen-Sen

    2008-12-01

    An exact solution to the two-dimensional scattering properties of an anisotropic elliptic cylinder for transverse electric polarization is presented. The internal field in an anisotropic elliptic cylinder is expressed as integral representations of Mathieu functions and Fourier series. The coefficients of the series expansion are obtained by imposing boundary conditions on the anisotropic-free-space interface. A matrix is developed to solve the nonorthogonality properties of Mathieu functions at the interface between two different media. Numerical results are given for the bistatic radar cross section and the amplitude of the total magnetic field along the x and y axes. The result is in agreement with that available as expected when an elliptic cylinder degenerates to a circular one.

  5. Status Report on the Passive Neutron Enrichment Meter (PNEM) for UF6 Cylinder Assay

    SciTech Connect

    Miller, Karen A.; Swinhoe, Martyn T.; Menlove, Howard O.; Marlow, Johnna B.

    2012-05-02

    The Passive Neutron Enrichment Meter (PNEM) is a nondestructive assay (NDA) system being developed at Los Alamos National Laboratory (LANL). It was designed to determine {sup 235}U mass and enrichment of uranium hexafluoride (UF{sub 6}) in product, feed, and tails cylinders (i.e., 30B and 48Y cylinders). These cylinders are found in the nuclear fuel cycle at uranium conversion, enrichment, and fuel fabrication facilities. The PNEM is a {sup 3}He-based neutron detection system that consists of two briefcase-sized detector pods. A photograph of the system during characterization at LANL is shown in Fig. 1. Several signatures are currently being studied to determine the most effective measurement and data reduction technique for unfolding {sup 235}U mass and enrichment. The system collects total neutron and coincidence data for both bare and cadmium-covered detector pods. The measurement concept grew out of the success of the Uranium Cylinder Assay System (UCAS), which is an operator system at Rokkasho Enrichment Plant (REP) that uses total neutron counting to determine {sup 235}U mass in UF{sub 6} cylinders. The PNEM system was designed with higher efficiency than the UCAS in order to add coincidence counting functionality for the enrichment determination. A photograph of the UCAS with a 48Y cylinder at REP is shown in Fig. 2, and the calibration measurement data for 30B product and 48Y feed and tails cylinders is shown in Fig. 3. The data was collected in a low-background environment, meaning there is very little scatter in the data. The PNEM measurement concept was first presented at the 2010 Institute of Nuclear Materials Management (INMM) Annual Meeting. The physics design and uncertainty analysis were presented at the 2010 International Atomic Energy Agency (IAEA) Safeguards Symposium, and the mechanical and electrical designs and characterization measurements were published in the ESARDA Bulletin in 2011.

  6. Large-eddy simulations of a flexible cylinder in axial flow

    NASA Astrophysics Data System (ADS)

    Karami, Behrouz; Balaras, Elias; Bardet, Philippe

    2015-11-01

    A slender cylinder immersed in axial flow shows different behavior for different flow and material properties. Several studies have pointed to the importance of the dimensionless velocity, U = (ρA / EI)0.5Uo D , relating the fluid and structural inertia. However, it is not clear how this behavior changes for different Reynolds numbers and flow regimes, while keeping U constant. In this study a slender cylinder immersed in axial flow is considered as an one-dimensional beam. The fluid-structure interaction is simulated using an immersed-boundary method for a series of Re numbers. A non-linear Euler-Bernouli hypothesis is utilized to account for the deflection and rotation of the cylinder. It is observed that for small dimensionless velocities the cylinder oscillates with small amplitude around its axis. Increasing U results in buckling of the cylinder. For higher U beam looses its quasi steady buckled state and flutters. It is investigated that how this behavior changes for different Re and different flow regimes (laminar vs turbulent boundary layers). Overall buckling occurs at higher U at laminar flow conditions. The results are in agreement both qualitatively and quantitatively with experiments in the literature.

  7. Fano-like resonance emerging from magnetic and electric plasmon mode coupling in small arrays of gold particles

    PubMed Central

    Bakhti, Saïd; Tishchenko, Alexandre V.; Zambrana-Puyalto, Xavier; Bonod, Nicolas; Dhuey, Scott D.; Schuck, P. James; Cabrini, Stefano; Alayoglu, Selim; Destouches, Nathalie

    2016-01-01

    In this work we theoretically and experimentally analyze the resonant behavior of individual 3 × 3 gold particle oligomers illuminated under normal and oblique incidence. While this structure hosts both dipolar and quadrupolar electric and magnetic delocalized modes, only dipolar electric and quadrupolar magnetic modes remain at normal incidence. These modes couple into a strongly asymmetric spectral response typical of a Fano-like resonance. In the basis of the coupled mode theory, an analytical representation of the optical extinction in terms of singular functions is used to identify the hybrid modes emerging from the electric and magnetic mode coupling and to interpret the asymmetric line profiles. Especially, we demonstrate that the characteristic Fano line shape results from the spectral interference of a broad hybrid mode with a sharp one. This structure presents a special feature in which the electric field intensity is confined on different lines of the oligomer depending on the illumination wavelength relative to the Fano dip. This Fano-type resonance is experimentally observed performing extinction cross section measurements on arrays of gold nano-disks. The vanishing of the Fano dip when increasing the incidence angle is also experimentally observed in accordance with numerical simulations. PMID:27580515

  8. Fano-like resonance emerging from magnetic and electric plasmon mode coupling in small arrays of gold particles

    NASA Astrophysics Data System (ADS)

    Bakhti, Saïd; Tishchenko, Alexandre V.; Zambrana-Puyalto, Xavier; Bonod, Nicolas; Dhuey, Scott D.; Schuck, P. James; Cabrini, Stefano; Alayoglu, Selim; Destouches, Nathalie

    2016-09-01

    In this work we theoretically and experimentally analyze the resonant behavior of individual 3 × 3 gold particle oligomers illuminated under normal and oblique incidence. While this structure hosts both dipolar and quadrupolar electric and magnetic delocalized modes, only dipolar electric and quadrupolar magnetic modes remain at normal incidence. These modes couple into a strongly asymmetric spectral response typical of a Fano-like resonance. In the basis of the coupled mode theory, an analytical representation of the optical extinction in terms of singular functions is used to identify the hybrid modes emerging from the electric and magnetic mode coupling and to interpret the asymmetric line profiles. Especially, we demonstrate that the characteristic Fano line shape results from the spectral interference of a broad hybrid mode with a sharp one. This structure presents a special feature in which the electric field intensity is confined on different lines of the oligomer depending on the illumination wavelength relative to the Fano dip. This Fano-type resonance is experimentally observed performing extinction cross section measurements on arrays of gold nano-disks. The vanishing of the Fano dip when increasing the incidence angle is also experimentally observed in accordance with numerical simulations.

  9. Synaptic vesicles isolated from the electric organ of Torpedo californica and from the central nervous system of Mus musculus contain small ribonucleic acids (sRNAs).

    PubMed

    Li, Huinan; Wu, Cheng; Aramayo, Rodolfo; Sachs, Matthew S; Harlow, Mark L

    2017-06-01

    Synaptic vesicles (SVs) are presynaptic organelles that load and release small molecule neurotransmitters at chemical synapses. In addition to classic neurotransmitters, we have demonstrated that SVs isolated from the Peripheral Nervous Systems (PNS) of the electric organ of Torpedo californica, a model cholinergic synapse, and SVs isolated from the Central Nervous System (CNS) of Mus musculus (mouse) contain small ribonucleic acids (sRNAs; ≤ 50 nucleotides) (Scientific Reports, 5:1-14(14918) Li et al. (2015) [1]). Our previous publication provided the five most abundant sequences associated with the T. californica SVs, and the ten most abundant sequences associated with the mouse SVs, representing 59% and 39% of the total sRNA reads sequenced, respectively). We provide here a full repository of the SV sRNAs sequenced from T. californica and the mouse deposited in the NCBI as biosamples. Three data studies are included: SVs isolated from the electric organ of T. californica using standard techniques, SVs isolated from the electric organ of T. californica using standard techniques with an additional affinity purification step, and finally, SVs isolated from the CNS of mouse. The three biosamples are available at https://www.ncbi.nlm.nih.gov/biosample/ SRS1523467, SRS1523466, and SRS1523472 respectively.

  10. Calculations of electric dipole moments and static dipole polarizabilities based on the two-component normalized elimination of the small component method.

    PubMed

    Yoshizawa, Terutaka; Zou, Wenli; Cremer, Dieter

    2016-11-14

    The analytical energy gradient and Hessian of the two-component Normalized Elimination of the Small Component (2c-NESC) method with regard to the components of the electric field are derived and used to calculate spin-orbit coupling (SOC) corrected dipole moments and dipole polarizabilities of molecules, which contain elements with high atomic number. Calculated 2c-NESC dipole moments and isotropic polarizabilities agree well with the corresponding four-component-Dirac Hartree-Fock or density functional theory values. SOC corrections for the electrical properties are in general small, but become relevant for the accurate prediction of these properties when the molecules in question contain sixth and/or seventh period elements (e.g., the SO effect for At2 is about 10% of the 2c-NESC polarizability). The 2c-NESC changes in the electric molecular properties are rationalized in terms of spin-orbit splitting and SOC-induced mixing of frontier orbitals with the same j = l + s quantum numbers.

  11. Calculations of electric dipole moments and static dipole polarizabilities based on the two-component normalized elimination of the small component method

    NASA Astrophysics Data System (ADS)

    Yoshizawa, Terutaka; Zou, Wenli; Cremer, Dieter

    2016-11-01

    The analytical energy gradient and Hessian of the two-component Normalized Elimination of the Small Component (2c-NESC) method with regard to the components of the electric field are derived and used to calculate spin-orbit coupling (SOC) corrected dipole moments and dipole polarizabilities of molecules, which contain elements with high atomic number. Calculated 2c-NESC dipole moments and isotropic polarizabilities agree well with the corresponding four-component-Dirac Hartree-Fock or density functional theory values. SOC corrections for the electrical properties are in general small, but become relevant for the accurate prediction of these properties when the molecules in question contain sixth and/or seventh period elements (e.g., the SO effect for At2 is about 10% of the 2c-NESC polarizability). The 2c-NESC changes in the electric molecular properties are rationalized in terms of spin-orbit splitting and SOC-induced mixing of frontier orbitals with the same j = l + s quantum numbers.

  12. Achieving transparency and maximizing scattering with metamaterial-coated conducting cylinders.

    PubMed

    Irci, Erdinc; Ertürk, Vakur B

    2007-11-01

    In this work, the electromagnetic interaction of plane waves with infinitely long metamaterial-coated conducting cylinders is considered. Different from "conjugate" pairing of double-positive (DPS) and double-negative (DNG) or epsilon-negative (ENG) and mu-negative (MNG) concentric cylinders, achieving transparency and maximizing scattering are separately achieved by covering perfect electric conductor (PEC) cylinders with simple (i.e., homogeneous, isotropic, and linear) metamaterial coatings. The appropriate constitutive parameters of such metamaterials are investigated for Transverse Magnetic (TM) and in particular for Transverse Electric (TE) polarizations. For TE polarization it is found out that the metamaterial-coating permittivity has to be in the 0cylinders are considered, the analytically found relation between epsilonc and the ratio of core-coating radii, gamma, should be modified in a sense that scattering from the PEC core is canceled by the coating. Furthermore, replacing epsilon by mu (and vice versa) does not lead to the same conclusions for TM polarization unless the PEC cylinder is replaced by a perfect magnetic conductor (PMC) cylinder. On the other hand, scattering maximization can also be achieved in the TM polarization case when coating permeability muc<0, whereas transparency requires large |muc| for this polarization. Numerical results in the form of normalized monostatic and bistatic echo widths, which demonstrate the transparency and scattering maximization phenomena, are given and possible application areas are discussed.

  13. Analysis of condensation on a horizontal cylinder with unknown wall temperature and comparison with the Nusselt model of film condensation

    NASA Technical Reports Server (NTRS)

    Bahrami, Parviz A.

    1996-01-01

    Theoretical analysis and numerical computations are performed to set forth a new model of film condensation on a horizontal cylinder. The model is more general than the well-known Nusselt model of film condensation and is designed to encompass all essential features of the Nusselt model. It is shown that a single parameter, constructed explicitly and without specification of the cylinder wall temperature, determines the degree of departure from the Nusselt model, which assumes a known and uniform wall temperature. It is also known that the Nusselt model is reached for very small, as well as very large, values of this parameter. In both limiting cases the cylinder wall temperature assumes a uniform distribution and the Nusselt model is approached. The maximum deviations between the two models is rather small for cases which are representative of cylinder dimensions, materials and conditions encountered in practice.

  14. Dynamic Friction Performance of a Pneumatic Cylinder with Al2O3 Film on Cylinder Surface.

    PubMed

    Chang, Ho; Lan, Chou-Wei; Wang, Hao-Xian

    2015-11-01

    A friction force system is proposed for accurately measuring friction force and motion properties produced by reciprocating motion of piston in a pneumatic cylinder. In this study, the proposed system is used to measure the effects of lubricating greases of different viscosities on the friction properties of pneumatic cylinder, and improvement of stick-slip motion for the cylinder bore by anodizing processes. A servo motor-driven ball screw is used to drive the pneumatic cylinder to be tested and to measure the change in friction force of the pneumatic cylinder. Experimental results show, that under similar test conditions, the lubricating grease with viscosity VG100 is best suited for measuring reciprocating motion of the piston of pneumatic cylinder. The wear experiment showed that, in the Al2O3 film obtained at a preset voltage 40 V in the anodic process, the friction coefficient and hardness decreased by 55% and increased by 274% respectively, thus achieving a good tribology and wear resistance. Additionally, the amplitude variation in the friction force of the pneumatic cylinder wall that received the anodizing treatment was substantially reduced. Additionally, the stick-slip motion of the pneumatic cylinder during low-speed motion was substantially improved.

  15. Experimental Evaluation of a Method for Turbocharging Four-Stroke, Single Cylinder, Internal Combustion Engines

    NASA Astrophysics Data System (ADS)

    Buchman, Michael; Winter, Amos

    2015-11-01

    Turbocharging an engine increases specific power, improves fuel economy, reduces emissions, and lowers cost compared to a naturally aspirated engine of the same power output. These advantages make turbocharging commonplace for multi-cylinder engines. Single cylinder engineers are not commonly turbocharged due to the phase lag between the exhaust stroke, which powers the turbocharger, and the intake stroke, when air is pumped into the engine. Our proposed method of turbocharging single cylinder engines is to add an ``air capacitor'' to the intake manifold, an additional volume that acts as a buffer to store compressed air between the exhaust and intake strokes, and smooth out the pressure pulses from the turbocharger. This talk presents experimental results from a single cylinder, turbocharged diesel engine fit with various sized air capacitors. Power output from the engine was measured using a dynamometer made from a generator, with the electrical power dissipated with resistive heating elements. We found that intake air density increases with capacitor size as theoretically predicted, ranging from 40 to 60 percent depending on heat transfer. Our experiment was able to produce 29 percent more power compared to using natural aspiration. These results validated that an air capacitor and turbocharger may be a simple, cost effective means of increasing the power density of single cylinder engines.

  16. Reliable, Efficient and Cost-Effective Electric Power Converter for Small Wind Turbines Based on AC-link Technology

    SciTech Connect

    Darren Hammell; Mark Holveck; DOE Project Officer - Keith Bennett

    2006-08-01

    Grid-tied inverter power electronics have been an Achilles heel of the small wind industry, providing opportunity for new technologies to provide lower costs, greater efficiency, and improved reliability. The small wind turbine market is also moving towards the 50-100kW size range. The unique AC-link power conversion technology provides efficiency, reliability, and power quality advantages over existing technologies, and Princeton Power will adapt prototype designs used for industrial asynchronous motor control to a 50kW small wind turbine design.

  17. The dish-Rankine SCSTPE program (Engineering Experiment no. 1). [systems engineering and economic analysis for a small community solar thermal electric system

    NASA Technical Reports Server (NTRS)

    Pons, R. L.; Grigsby, C. E.

    1980-01-01

    Activities planned for phase 2 Of the Small Community Solar Thermal Power Experiment (PFDR) program are summarized with emphasis on a dish-Rankine point focusing distributed receiver solar thermal electric system. Major design efforts include: (1) development of an advanced concept indirect-heated receiver;(2) development of hardware and software for a totally unmanned power plant control system; (3) implementation of a hybrid digital simulator which will validate plant operation prior to field testing; and (4) the acquisition of an efficient organic Rankine cycle power conversion unit. Preliminary performance analyses indicate that a mass-produced dish-Rankine PFDR system is potentially capable of producing electricity at a levelized busbar energy cost of 60 to 70 mills per KWh and with a capital cost of about $1300 per KW.

  18. UF{sub 6} cylinder fire test

    SciTech Connect

    Park, S.H.

    1991-12-31

    With the increasing number of nuclear reactors for power generation, there is a comparable increase in the amount of UF{sub 6} being transported. Likewise, the probability of having an accident involving UF{sub 6}-filled cylinders also increases. Accident scenarios which have been difficult to assess are those involving a filled UF{sub 6} cylinder subjected to fire. A study is underway at the Oak Ridge K-25 Site, as part of the US DOE Enrichment Program, to provide empirical data and a computer model that can be used to evaluate various cylinder-in-fire scenarios. It is expected that the results will provide information leading to better handling of possible fire accidents as well as show whether changes should be made to provide different physical protection during shipment. The computer model being developed will be capable of predicting the rupture of various cylinder sizes and designs as well as the amount of UF{sub 6}, its distribution in the cylinder, and the conditions of the fire.

  19. Guided Circumferential Waves in Layered Poroelastic Cylinders

    NASA Astrophysics Data System (ADS)

    Shah, S. A.; Apsar, G.

    2016-12-01

    The present paper investigates the propagation of time harmonic circumferential waves in a two-dimensional hollow poroelastic cylinder with an inner shaft (shaft-bearing assembly). The hollow poroelastic cylinder and inner shaft are assumed to be infinite in axial direction. The outer surface of the cylinder is stress free and at the interface, between the inner shaft and the outer cylinder, it is assumed to be free sliding and the interfacial shear stresses are zero, also the normal stress and radial displacements are continuous. The frequency equation of guided circumferential waves for a permeable and an impermeable surface is obtained. When the angular wave number vanish the frequency equation of guided circumferential waves for a permeable and an impermeable surface degenerates and the dilatational and shear waves are uncoupled. Shear waves are independent of the nature of surface. The frequency equation of a permeable and an impermeable surface for bore-piston assembly is obtained as a particular case of the model under consideration when the outer radius of the hollow poroelastic cylinder tends to infinity. Results of previous studies are obtained as a particular case of the present study. Nondimensional frequency as a function of wave number is presented graphically for two types of models and discussed. Numerical results show that, in general, the first modes are linear for permeable and impermeable surfaces and the frequency of a permeable surface is more than that of an impermeable surface.

  20. Vision-guided gripping of a cylinder

    NASA Technical Reports Server (NTRS)

    Nicewarner, Keith E.; Kelley, Robert B.

    1991-01-01

    The motivation for vision-guided servoing is taken from tasks in automated or telerobotic space assembly and construction. Vision-guided servoing requires the ability to perform rapid pose estimates and provide predictive feature tracking. Monocular information from a gripper-mounted camera is used to servo the gripper to grasp a cylinder. The procedure is divided into recognition and servo phases. The recognition stage verifies the presence of a cylinder in the camera field of view. Then an initial pose estimate is computed and uncluttered scan regions are selected. The servo phase processes only the selected scan regions of the image. Given the knowledge, from the recognition phase, that there is a cylinder in the image and knowing the radius of the cylinder, 4 of the 6 pose parameters can be estimated with minimal computation. The relative motion of the cylinder is obtained by using the current pose and prior pose estimates. The motion information is then used to generate a predictive feature-based trajectory for the path of the gripper.

  1. The Cylinder and Semicylinder in Subsonic Flow

    NASA Technical Reports Server (NTRS)

    Bingham, Harry J.; Weimer, David K..; Griffith, Wayland

    1952-01-01

    In studying the diffraction of shock waves around various two-dimensional obstacles we have observed that flow separation and the formation of vortices contributes in an important way to transient loading of the obstacle. The cases of a cylinder and semicylinder are especially interesting because the breakaway point is not clearly defined as it is for objects having sharp corners. Accordingly a number of experiments have been made in the shock tube to observe the influence of Reynolds number and Mach number on the transient flow patterns about a cylinder and about a semicylinder mounted on a smooth plane. Some differences might be anticipated since the plane would impose a symmetry on the flow and produce a viscous boundary layer for which there is no counterpart with the cylinder. In the course of these experiments it was noted that a condition of steady subsonic flow about both the cylinder and semicylinder was approached. Thus a comparison with von Karrnan's theoretical calculation of the drag on a cylinder, from certain characteristics of its wake or "vortex street", was undertaken.

  2. Compressive testing of filament-wound cylinders

    NASA Technical Reports Server (NTRS)

    Jensen, David W.; Hipp, Patrick A.

    1991-01-01

    An experimental investigation has been conducted on the compressive buckling and failure of filament-wound circular cylinders. This investigation identifies one of the relationships between structural performance and scale, as well as some of the causes of reduced structural performance in large-scale structures. It is hypothesized that this effect is related to two conditions: first, the number of fiber tow undulations; and second, the percentage of weak interfaces within the structure. The effect of winding pattern and the resulting location of the fiber undulations were studied by varying the winding parameters. Three types of cylinders were manufactured from Amoco T650-35/1908 graphite/epoxy preimpregnated tow with different winding sequences (0/+/-60)s, (+/-30/90)s, and (90/+/-30)s. The (90/+/-30)s cylinders were manufactured with two different winding patterns (distributed and classical) and radius-to-thickness ratios (15 and 55). All cylinders were loaded in compression to failure. Comparisons of the compressive strength and failure modes demonstrate the relationship between the winding parameters, scale, and structural performance of filament-wound composite cylinders.

  3. Horseshoe vortex formation around a cylinder

    NASA Astrophysics Data System (ADS)

    Eckerle, W. A.

    A turbulent boundary layer approaching a local obstruction, such as when annulus wall boundary layers encounter airfoils and support struts, creates a critical problem in gas turbine engines. The slower portion of the approaching boundary layer cannot negotiate the adverse pressure gradient generated by the obstruction and consequently separates from the endwall. The resulting flow field includes a horseshoe vortex that is swept downstream around the body. The separation affects both the local heat transfer coefficients and aerodynamic losses in the endwall region. This investigation evaluated the detailed flow processes that lead to the symmetric horseshoe vortex formation around a large-diameter cylinder. Test conditions included a freestream velocity of 30.5 m/sec, a Reynolds number based on cylinder diameter of 5.5 x 10 to the 5th power, and a boundary-layer thickness equal to 13 percent of the cylinder diameter. The final report presents endwall and cylinder surface flow visualizations, endwall and cylinder static pressure distributions, and five-hole probe measurements in the separation region.

  4. Low-frequency oscillations of a cylinder in a viscous fluid

    NASA Astrophysics Data System (ADS)

    Amin, Norsarahaida

    1988-05-01

    The flow induced by a circular cylinder oscillating in a viscous fluid when the amplitude of the oscillation is small and the frequecy is low is considered. This solution, obtained by the method of matched asymptotic expansions, is compared with the solution obtained from an Oseen approximation to the governing equations by Andres and Ingard (1953).

  5. Natural convection in a horizontal cylinder with axial rotation

    NASA Astrophysics Data System (ADS)

    Sánchez, Odalys; Mercader, Isabel; Batiste, Oriol; Alonso, Arantxa

    2016-06-01

    We study the problem of thermal convection in a laterally heated horizontal cylinder rotating about its axis. A cylinder of aspect ratio Γ =H /2 R =2 containing a small Prandtl number fluid (σ =0.01 ) representative of molten metals and molten semiconductors at high temperature is considered. We focus on a slow rotation regime (Ω <8 ), where the effects of rotation and buoyancy forces are comparable. The Navier-Stokes and energy equations with the Boussinesq approximation are solved numerically to calculate the basic states, analyze their linear stability, and compute several secondary flows originated from the instabilities. Due to the confined cylindrical geometry—the presence of lateral walls and lids—all the flows are completely three dimensional, even the basic steady states. Results characterizing the basic states as the rotation rate increases are presented. As it occurred in the nonrotating case for higher values of the Prandtl number, two curves of steady states with the same symmetric character coexist for moderate values of the Rayleigh number. In the range of Ω considered, rotation has a stabilizing effect only for very small values. As the value of the rotation rate approaches Ω =3.5 and Ω =4.5 , the scenario of bifurcations becomes more complex due to the existence in both cases of very close bifurcations of codimension 2, which in the latter case involve both curves of symmetric solutions.

  6. Flow interaction between a streamwise oscillating cylinder and a downstream stationary cylinder

    NASA Astrophysics Data System (ADS)

    Xu, S. J.; Gan, L.; Zhou, Y.

    2016-11-01

    In this paper, we present some experimental results about the physical effects of a cylinder's streamwise oscillation motion on a downstream one in a tandem arrangement. The upstream cylinder undergoes a controlled simple harmonic oscillation at amplitudes A/ d = 0.2-0.8, where d is the cylinder diameter, and the frequency ratio of f_e/f_s = 0-3.0, where f_e is the cylinder oscillation frequency and f_s is the natural frequency of vortex shedding from a single stationary cylinder. Under these conditions, the vortex shedding is locked to the controlled oscillation motion. Flow visualisation using the planar laser-induced fluorescence and qualitative measurements using hot-wire anemometry reveal three distinct flow regimes behind the downstream cylinder. For f_e/f_s > (f_e/f_s)_c, where (f_e/f_s)_c is a critical frequency ratio which depends on A/ d and Reynolds number Re, a so-called SA-mode occurs. The upstream oscillating cylinder generates binary vortices symmetrically arranged about the centreline, each containing a pair of counter-rotating vortices, and the downstream cylinder sheds vortices alternately at 0.5f_e. For 0.7-1.0 < f_e/f_s < (f_e/f_s)_c a complex vortex street that consists of two outer rows of vortices generated by the oscillating cylinder and two inner rows of vortices shed from the downstream stationary cylinder, which is referred to as AA-mode. For 0.3-0.6 < f_e/f_s< 0.8-1.0, one single staggered vortex street (A-mode) is observed. It is also found that, when f_e/f_s is near unity, the streamwise interaction of the two cylinders gives rise to the most energetic wake in the cross-stream direction, in terms of its maximum width, and the wake is AA-mode-like. The effects of other parameters such as the spacing between the two cylinders, Re and A/ d on the flow pattern are also discussed in details. The observations are further compared to the stationary tandem cylinder cases.

  7. Heat Transfer Over the Circumference of a Heated Cylinder in Transverse Flow

    NASA Technical Reports Server (NTRS)

    Schmidt, Ernst; Wenner, Karl

    1943-01-01

    A method for recording the local heat-transfer coefficients on bodies in flow was developed. The cylinder surface was kept at constant temperature by the condensation of vapor except for a narrow strip which is heated separately to the same temperature by electricity. The heat-transfer coefficient at each point was determined from the electric heat output and the temperature increase. The distribution of the heat transfer along the circumference of cylinders was recorded over a range of Reynolds numbers of from 5000 to 426,000. The pressure distribution was measured at the same time. At Reynolds numbers up to around 100,000 high maximums of the heat transfer occurred in the forward stagnation point at and on the rear side at 180C, while at around 80 the heat-transfer coefficient on both sides of the cylinder behind the forward stagnation point manifested distinct minimums. Two other maximums occurred at around 115 C behind the forward stagnation point between 170,000 and 426,000. At 426,000 the heat transfer at the location of those maximums was almost twice as great as in the forward stagnation point, and the rear half of the cylinder diffused about 60 percent of the entire heat, The tests are compared with the results of other experimental and theoretical investigations.

  8. Gas adsorption and desorption effects on cylinders and their importance for long-term gas records

    NASA Astrophysics Data System (ADS)

    Leuenberger, M. C.; Schibig, M. F.; Nyfeler, P.

    2015-12-01

    .0003 ppm °C-1 for aluminium cylinders. The reversed temperature dependence for aluminium cylinders points to significantly lower desorption energies than for steel cylinders and due to the small values, they might at least partly be influenced by temperature, permeation from/to sealing materials, and gas-consumption-induced pressure changes. Temperature coefficients for CH4, CO, and H2O adsorption were, within their error bands, insignificant. These results do indicate the need for careful selection and usage of gas cylinders for high-precision calibration purposes such as requested in trace gas applications.

  9. A pneumatic cylinder driving polyhedron mobile mechanism

    NASA Astrophysics Data System (ADS)

    Ding, Wan; Kim, Sung-Chan; Yao, Yan-An

    2012-03-01

    A novel pneumatic cylinder driving polyhedron mobile mechanism is proposed in this paper. The mechanism is comprised of 5 tetrahedrons which includes a pneumatic cylinder in each edge. It locomotes by rolling and the rolling principle refers to the center of mass (CM) of the mechanism moved out of the supporting area and let it tip over through the controlling of the motion sequence of these cylinders. Firstly, the mathematical model is built to analysis the relation between the configuration and the CM of the mechanism. Then, a binary control strategy is developed to simplify and improve the control of this mobile mechanism. After that, dynamic simulation is performed to testify the analytical validity and feasibility of the rolling gaits. At last, a prototype is fabricated to achieve the rolling successfully to demonstrate the proposed concept.

  10. Optimum cylinder cooling for advanced diesel engines

    SciTech Connect

    Trenc, F.; Rodman, S.; Skerget, L.; Delic, M.

    1998-07-01

    Continuous demand for higher specific engine output simultaneously introduces problems of higher mechanical and thermal stresses of the engine components. Uneven temperature distribution in the cylinder wall of a diesel engine, especially when air-cooled, is well known. Peak local temperatures, large circumferential and longitudinal temperature gradients provoke deformations that, in turn, affect the reliability of the engine. As the result of intensive numerical and experimental investigations, a horizontal, curved channel fed with engine lubrication oil was introduced in the upper part of the air-cooled cylinder. Optimization of the channel design, its position, and determination of suitable asymmetrical split oil flow have led to more favorable cylinder temperature distribution, similar to that obtained by advanced water-cooled engines. Analyses of the local laminar oil-flow phenomena and local heat transfer distribution is curved channels are discussed in the paper and can be successfully applied to advanced liquid-cooled engines.

  11. Optimum cylinder cooling for advanced diesel engines

    SciTech Connect

    Trenc, F.; Rodman, S.; Skerget, L.; Delic, M.

    1996-12-31

    Continuous demand for higher specific engine output simultaneously introduces problems of higher mechanical and thermal stresses of the engine components. Uneven temperature distribution in the cylinder wall of a Diesel engine, especially when air-cooled, is well known. Peak local temperatures, large circumferential and longitudinal temperature gradients provoke deformations that in turn affect the reliability of the engine. As the result of intensive numerical and experimental investigations a horizontal, curved channel fed with engine lubrication oil was introduced in the upper part of the air-cooled cylinder. Optimization of the channel design, its position, and determination of suitable asymmetrical split oil-flow have led to more favorable cylinder temperature distribution, similar to that obtained by advanced water-cooled engines. Analyses of the local laminar oil-flow phenomena and local heat transfer distribution in curved channels can be successfully and effectively applied to advanced liquid-cooled engines.

  12. Sky reconstruction for the Tianlai cylinder array

    NASA Astrophysics Data System (ADS)

    Zhang, Jiao; Zuo, Shi-Fan; Ansari, Reza; Chen, Xuelei; Li, Yi-Chao; Wu, Feng-Quan; Campagne, Jean-Eric; Magneville, Christophe

    2016-10-01

    We apply our sky map reconstruction method for transit type interferometers to the Tianlai cylinder array. The method is based on spherical harmonic decomposition, and can be applied to a cylindrical array as well as dish arrays and we can compute the instrument response, synthesized beam, transfer function and noise power spectrum. We consider cylinder arrays with feed spacing larger than half a wavelength and, as expected, we find that the arrays with regular spacing have grating lobes which produce spurious images in the reconstructed maps. We show that this problem can be overcome using arrays with a different feed spacing on each cylinder. We present the reconstructed maps, and study the performance in terms of noise power spectrum, transfer function and beams for both regular and irregular feed spacing configurations.

  13. Vortex noise from nonrotating cylinders and airfoils

    NASA Technical Reports Server (NTRS)

    Schlinker, R. H.; Amiet, R. K.; Fink, M. R.

    1976-01-01

    An experimental study of vortex-shedding noise was conducted in an acoustic research tunnel over a Reynolds-number range applicable to full-scale helicopter tail-rotor blades. Two-dimensional tapered-chord nonrotating models were tested to simulate the effect of spanwise frequency variation on the vortex-shedding mechanism. Both a tapered circular cylinder and tapered airfoils were investigated. The results were compared with data for constant-diameter cylinder and constant-chord airfoil models also tested during this study. Far-field noise, surface pressure fluctuations, and spanwise correlation lengths were measured for each configuration. Vortex-shedding noise for tapered cylinders and airfoils was found to contain many narrowband-random peaks which occurred within a range of frequencies corresponding to a predictable Strouhal number referenced to the maximum and minimum chord. The noise was observed to depend on surface roughness and Reynolds number.

  14. Flow in a partially filled rotating cylinder

    NASA Astrophysics Data System (ADS)

    Shadday, M. A., Jr.

    Axial flow in a rapidly rotating cylinder, partially filled with a viscous, incompressible fluid is measured with a laser-Doppler velocimeter. The cylinder has a vertical axis of rotation, and the axial circulation is induced by rotating a coaxially mounted disk at the top endcap slightly faster than the cylinder. The experimental results are compared with the predictions of a finite-difference model of the flow, and the correlation is qualitatively good. The axial circulation in the fluid layer is confined primarily to E(1/3) shear layers along the lateral boundaries, where E is the Ekman number. The radial transport in the Ekman layers is essentially unaffected by the presence of the free surface. It will be shown that this leads to axial transport in an E(1/3) boundary layer along the free surface.

  15. Flow in a partially filled rotating cylinder

    NASA Astrophysics Data System (ADS)

    Shadday, M. A., Jr.

    1982-05-01

    Axial flow in a rapidly rotating cylinder, partially filled with a viscous, incompressible fluid is measured with a laser Doppler velocimeter. The cylinder has a vertical axis of rotation, and the axial circulation is induced by rotating a coaxially mounted disk at the top endcap slightly faster than the cylinder. The experimental results are compared with the prediction of a finite difference model of the flow, and the correlation is qualitatively good. The axial circulation in the fluid layer is confined primarily to E/sup 1/3/ shear layers along the lateral boundaries, where E is the Ekman number. The radial transport in the Ekman layers is essentially unaffected by the presence of the free surface. It will be shown that this leads to axial transport in an E/sup 1/3/ boundary layer along the free surface.

  16. UF{sub 6} cylinder inspections at PGDP

    SciTech Connect

    Lamb, G.W.; Whinnery, W.N.

    1991-12-31

    Routine inspections of all UF{sub 6} cylinders at the Paducah Gaseous Diffusion Plant have been mandated by the Department of Energy. A specific UF{sub 6} cylinder inspection procedure for what items to inspect and training for the operators prior to inspection duty are described. The layout of the cylinder yards and the forms used in the inspections are shown. The large number of cylinders (>30,000) to inspect and the schedule for completion on the mandated time table are discussed. Results of the inspections and the actions to correct the deficiencies are explained. Future inspections and movement of cylinders for relocation of certain cylinder yards are defined.

  17. Pulsatile flow past an oscillating cylinder

    PubMed Central

    Qamar, Adnan; Seda, Robinson; Bull, Joseph L.

    2011-01-01

    A fundamental study to characterize the flow around an oscillating cylinder in a pulsatile flow environment is investigated. This work is motivated by a new proposed design of the total artificial lung (TAL), which is envisioned to provide better gas exchange. The Navier–Stokes computations in a moving frame of reference were performed to compute the dynamic flow field surrounding the cylinder. Cylinder oscillations and pulsatile free-stream velocity were represented by two sinusoidal waves with amplitudes A and B and frequencies ωc and ω, respectively. The Keulegan–Carpenter number (Kc=Uo∕Dωc) was used to describe the frequency of the oscillating cylinder while the pulsatile free-stream velocity was fixed by imposing ω∕Kc=1 for all cases investigated. The parameters of interest and their values were amplitude (0.5Dcylinder values (A=0.5, Kc=0.3, and Re=10 and 20). A lock-in phenomenon (cylinder oscillating frequency matched the vortex shedding frequency) was found when Kc=1 for all cases. This lock-in condition was attributed to be the cause of the rise in drag observed in that operating regime. For optimal performance of the modified TAL design it is recommended to operate the device at higher fiber oscillation amplitudes and lower Kc (avoiding the lock-in regime). PMID:21580804

  18. Pulsatile flow past an oscillating cylinder

    NASA Astrophysics Data System (ADS)

    Qamar, Adnan; Seda, Robinson; Bull, Joseph L.

    2011-04-01

    A fundamental study to characterize the flow around an oscillating cylinder in a pulsatile flow environment is investigated. This work is motivated by a new proposed design of the total artificial lung (TAL), which is envisioned to provide better gas exchange. The Navier-Stokes computations in a moving frame of reference were performed to compute the dynamic flow field surrounding the cylinder. Cylinder oscillations and pulsatile free-stream velocity were represented by two sinusoidal waves with amplitudes A and B and frequencies ωc and ω, respectively. The Keulegan-Carpenter number (Kc=Uo/Dωc) was used to describe the frequency of the oscillating cylinder while the pulsatile free-stream velocity was fixed by imposing ω /Kc=1 for all cases investigated. The parameters of interest and their values were amplitude (0.5Dcylinder values (A=0.5, Kc=0.3, and Re=10 and 20). A lock-in phenomenon (cylinder oscillating frequency matched the vortex shedding frequency) was found when Kc=1 for all cases. This lock-in condition was attributed to be the cause of the rise in drag observed in that operating regime. For optimal performance of the modified TAL design it is recommended to operate the device at higher fiber oscillation amplitudes and lower Kc (avoiding the lock-in regime).

  19. Flow development and structural loading on dual step cylinders in laminar shedding regime

    NASA Astrophysics Data System (ADS)

    McClure, J.; Morton, C.; Yarusevych, S.

    2015-06-01

    The flow development over a dual step cylinder is investigated numerically at a Reynolds number (ReD) of 150 for a range of aspect ratios, 0.2 ≤ L/D ≤ 5, and diameter ratios, 1.1 ≤ D/d ≤ 4. The results reveal the following four distinct types of wake topology downstream of the larger diameter cylinder: (i) shedding of hairpin vortices, (ii) transient asymmetric shedding, (iii) primarily spanwise shedding, and (iv) no vortex shedding. Dominant vortex interactions are reconstructed for each regime. These interactions, involving half-loop vortex connections, vortex merging, and direct vortex connections are shown to occur periodically as the large and small cylinder structures undergo vortex dislocations. Topological schematics are introduced to relate the characteristic frequencies to the periodic vortex interactions. The observed types of wake topology are shown to produce distinctly different mean and fluctuating forces on the dual step cylinder. For lower aspect and diameter ratios (L/D ˜ 1 and D/d ˜ 1.5), a reduction in fluctuating lift of up to 80% can be achieved on the base cylinder with a minor reduction in mean drag (˜5%). The results indicate that similar performance improvements can be sustained by attaching multiple larger diameter cylinders to the base cylinder. The changes in the fluid forcing are shown to be related to the secondary flow produced by the downwash at the stepwise discontinuities. This process also involves the production of streamwise vorticity at the steps, which is shown to be associated with the deformation of the main spanwise vortical structures.

  20. Optimizing power cylinder lubrication on a large bore natural gas engine

    NASA Astrophysics Data System (ADS)

    Luedeman, Matthew R.

    More than 6000 integral compressors, located along America's natural gas pipelines, pump natural gas across the United States. These compressors are powered by 2-stroke, large bore natural gas burning engines. Lowering the operating costs, reducing the emissions, and ensuring that these engines remain compliant with future emission regulations are the drivers for this study. Substantial research has focused on optimizing efficiency and reducing the fuel derived emissions on this class of engine. However, significantly less research has focused on the effect and reduction of lubricating oil derived emissions. This study evaluates the impact of power cylinder lubricating oil on overall engine emissions with an emphasis on reducing oxidation catalyst poisoning. A traditional power cylinder lubricator was analyzed; power cylinder lubricating oil was found to significantly impact exhaust emissions. Lubricating oil was identified as the primary contributor of particulate matter production in a large bore natural gas engine. The particulate matter was determined to be primarily organic carbon, and most likely direct oil carryover of small oil droplets. The particulate matter production equated to 25% of the injected oil at a nominal power cylinder lubrication rate. In addition, power cylinder friction is considered the primary contributor to friction loss in the internal combustion engine. This study investigates the potential for optimizing power cylinder lubrication by controlling power cylinder injection to occur at the optimal time in the piston cycle. By injecting oil directly into the ring pack, it is believed that emissions, catalyst poisoning, friction, and wear can all be reduced. This report outlines the design and theory of two electronically controlled lubrication systems. Experimental results and evaluation of one of the systems is included.

  1. A Hybrid Approach To Tandem Cylinder Noise

    NASA Technical Reports Server (NTRS)

    Lockard, David P.

    2004-01-01

    Aeolian tone generation from tandem cylinders is predicted using a hybrid approach. A standard computational fluid dynamics (CFD) code is used to compute the unsteady flow around the cylinders, and the acoustics are calculated using the acoustic analogy. The CFD code is nominally second order in space and time and includes several turbulence models, but the SST k - omega model is used for most of the calculations. Significant variation is observed between laminar and turbulent cases, and with changes in the turbulence model. A two-dimensional implementation of the Ffowcs Williams-Hawkings (FW-H) equation is used to predict the far-field noise.

  2. Cylinder head structure for internal combustion engines

    SciTech Connect

    Taguchi, T.; Takata, Y.; Tanaka, Y.

    1986-02-04

    This patent describes an engine cylinder head structure including a top wall formed with camshaft bearings, a bottom wall adapted to be attached to a cylinder block, and side walls connecting the top and bottom walls together. It also includes a cooling watter passage defined by the top, bottom and side walls, a transversely extending reinforcement rib formed in the top wall to project into the cooling water passage beneath each of the camshaft bearings and to extend between and interconnect the side walls.

  3. Cylinder wakes in flowing soap films

    SciTech Connect

    Vorobieff, P.; Ecke, R.E. ); Vorobieff, P. )

    1999-09-01

    We present an experimental characterization of cylinder wakes in flowing soap films. From instantaneous velocity and thickness fields, we find the vortex-shedding frequency, mean-flow velocity, and mean-film thickness. Using the empirical relationship between the Reynolds and Strouhal numbers obtained for cylinder wakes in three dimensions, we estimate the effective soap-film viscosity and its dependence on film thickness. We also compare the decay of vorticity with that in a simple Rankine vortex model with a dissipative term to account for air drag. [copyright] [ital 1999] [ital The American Physical Society

  4. Controllable parabolic-cylinder optical rogue wave.

    PubMed

    Zhong, Wei-Ping; Chen, Lang; Belić, Milivoj; Petrović, Nikola

    2014-10-01

    We demonstrate controllable parabolic-cylinder optical rogue waves in certain inhomogeneous media. An analytical rogue wave solution of the generalized nonlinear Schrödinger equation with spatially modulated coefficients and an external potential in the form of modulated quadratic potential is obtained by the similarity transformation. Numerical simulations are performed for comparison with the analytical solutions and to confirm the stability of the rogue wave solution obtained. These optical rogue waves are built by the products of parabolic-cylinder functions and the basic rogue wave solution of the standard nonlinear Schrödinger equation. Such rogue waves may appear in different forms, as the hump and paw profiles.

  5. Stress tests on cylinders and aluminum panels

    NASA Technical Reports Server (NTRS)

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

    1974-01-01

    An optimization study of composite stiffened cylinders is discussed. The mathematical model for the buckling has been coupled successfully with the optimization program AESOP. The buckling analysis is based on the use of the smeared theory for the buckling of stiffened orthotropic cylindrical shells. The loading, radius, and length of the cylinder are assumed to be known parameters. An optimum solution gives the value of cross-sectional dimensions and laminate orientations. The different types of buckling modes are identified. Mathematical models are developed to show the relationships of the parameters.

  6. Flame Movement and Pressure Development in an Engine Cylinder

    NASA Technical Reports Server (NTRS)

    Marvin, Charles F , Jr; Best, Robert D

    1932-01-01

    This investigation describes a visual method for making stroboscopic observations, through a large number of small windows, of the spread of flame throughout the combustion chamber of a gasoline engine. Data, secured by this method on a small engine burning gaseous fuels, are given to show the effects of mixture ratio, spark advance, engine speed, charge density, degree of dilution, compression ratio, and fuel composition on flame movement in the cylinder. Partial indicator diagrams showing pressure development during the combustion period are included. Although present knowledge is not sufficient to permit qualitative evaluation of the separate effects on flame movement of chemical reaction velocity, thermal expansion of burned gases, resonance, turbulence, and piston movement, the qualitative influence of certain of these factors on some of the diagrams is indicated.

  7. Effect of finite length on forced convection heat transfer from cylinders

    NASA Astrophysics Data System (ADS)

    Quarmby, A.; Al-Fakhri, A. A. M.

    1980-04-01

    Forced convection heat transfer from single cylinders of finite length is investigated experimentally with particular reference to the effect of aspect (length/diameter) ratio of the cylinder. It is found that for aspect ratios greater than 4 there is little further effect as aspect ratio increases to infinity. The disagreement between the correlations proposed by Zukauskas (1972) and Morgan (1975) is considered and resolved in favor of the Zukauskas correlation. A correlation is proposed for heat transfer from cylinders of low aspect ratio which in the limit agrees with the correlation for large aspect ratios and with the generally accepted correlation for turbulent heat transfer from isothermal flat plates for small aspect ratios.

  8. Mechanism of tonal noise generation from circular cylinder with spiral fin

    NASA Astrophysics Data System (ADS)

    Yamashita, Ryo; Hayashi, Hidechito; Okumura, Tetsuya; Hamakawa, Hiromitsu

    2014-12-01

    The pitch of the spiral finned tube influences seriously to the acoustic resonance in the heat exchanger. In this research, the flow characteristics in relating to the aeolian tone from the finned cylinder are studied by the numerical simulation. It is observed that the tonal noise generated from the finned tube at two pitch spaces. The ratio of the fin pitch to the cylinder diameter is changed at 0.11 and 0.27. The tone level increases and the frequency decreases with the pitch shorter. The separation flow from the cylinder generates the span-wise vortices, Karman vortices, and the separation flow from the fin generates the stream-wise vortices. When the fin pitch ratio is small, the stream-wise vortices line up to span-wise and become weak rapidly. Only the Karman vortices are remained and integrate in span. So the Karman vortex became large. This causes the low frequency and the large aeolian tone.

  9. Stabilization of Taylor-Couette flow due to time-periodic outer cylinder oscillation

    NASA Technical Reports Server (NTRS)

    Murray, B. T.; Mcfadden, G. B.; Coriell, S. R.

    1990-01-01

    The linear stability of circular Couette flow between concentric infinite cylinders is considered for the case when the inner cylinder is rotated at a constant angular velocity and the outer cylinder is driven sinusoidally in time with zero mean rotation. This configuration was studied experimentally by Walsh and Donnelly. The critical Reynolds numbers calculated from linear stability theory agree well with the experimental values, except at large modulation amplitudes and small frequencies. The theoretical values are obtained using Floquet theory implemented in two distinct approaches: a truncated Fourier series representation in time, and a fundamental solution matrix based on a Chebyshev pseudospectral representation in space. For large amplitude, low frequency modulation, the linear eigenfunctions are temporally complex, consisting of a quiescent region followed by rapid change in the perturbed flow velocities.

  10. Electrical transport properties of small diameter single-walled carbon nanotubes aligned on ST-cut quartz substrates

    PubMed Central

    2014-01-01

    A method is introduced to isolate and measure the electrical transport properties of individual single-walled carbon nanotubes (SWNTs) aligned on an ST-cut quartz, from room temperature down to 2 K. The diameter and chirality of the measured SWNTs are accurately defined from Raman spectroscopy and atomic force microscopy (AFM). A significant up-shift in the G-band of the resonance Raman spectra of the SWNTs is observed, which increases with increasing SWNTs diameter, and indicates a strong interaction with the quartz substrate. A semiconducting SWNT, with diameter 0.84 nm, shows Tomonaga-Luttinger liquid and Coulomb blockade behaviors at low temperatures. Another semiconducting SWNT, with a thinner diameter of 0.68 nm, exhibits a transition from the semiconducting state to an insulating state at low temperatures. These results elucidate some of the electrical properties of SWNTs in this unique configuration and help pave the way towards prospective device applications. PMID:25170326

  11. Low Reynolds number steady streaming around a cylinder at various orientations

    NASA Astrophysics Data System (ADS)

    Kotas, C. H.; Yoda, M.; Rogers, P. H.

    2003-11-01

    Lighthill [JFM 239:551-606 (1992)] recognized the possible role of steady streaming in the cochlea more than a decade ago. The role of streaming in the fish ear, however, remains uninvestigated. We hypothesize that the flow patterns due to acoustically induced streaming of the otoliths in the fish ear are ``visualized'' by hair cell ciliae on the sensory macula, much like a tufts visualization, and that these patterns play a role in how fish directionalize sound. Motivated by this hypothesis, steady streaming of a cylinder undergoing small amplitude oscillations in an ``infinite''' Newtonian fluid was studied using particle-image velocimetry. The cylinder was oscillated at various orientations θ = 0-45^rc, where θ is the angle between the oscillation and cylinder axes at cylinder Reynolds numbers ReD ≡ A D ω / ν = 50-200 and streaming Reynolds numbers Re ≡ A^2ω / ν < O(1) where A, ω and D are the cylinder oscillation amplitude, oscillation frequency and diameter, respectively, and ν is the fluid kinematic viscosity. The velocity data and flow patterns at θ = 0^rc are compared with previous results. The results at θ ne 0^rc are, to our knowledge, the first for this three-dimensional flow.

  12. Experimental evaluation of sound produced by two cylinders in a cross flow in various configurations

    NASA Astrophysics Data System (ADS)

    Bilka, Michael; Kerrian, Peter; Morris, Scott

    2012-11-01

    Cylinders in a cross flow is a canonical test case that is considered representative of industrial fluid flow problems, such as heat exchangers and aircraft landing gear. The general configurations are cylinders in tandem, parallel or staggered, which lead to several interesting flow phenomena such as wake cavity/wake interaction effects (tandem), symmetric/asymmetric wake behavior (parallel) or wake interaction/coanda effects (staggered), depending on relative location of the cylinders. In many cases, it is important to not only understand the flow interaction between the cylinders but also the acoustic consequence of such configurations. However, information on the acoustical behavior based on these configurations is relatively small compared to that of the steady aerodynamic and flow interaction behavior. The present work investigates the acoustic spectral properties of these configurations in order to characterize the sound produced by cylinder proximity and wake effects. The spectra are measured using an acoustic beam-forming technique to identify the sources and remove spurious content from the spectra.

  13. Energetically efficient proportional-integral-differential (PID) control of wake vortices behind a circular cylinder

    NASA Astrophysics Data System (ADS)

    Das, Pramode K.; Mathew, Sam; Shaiju, A. J.; Patnaik, B. S. V.

    2016-02-01

    The control of vortex shedding behind a circular cylinder is a precursor to a wide range of external shear flow problems in engineering, in particular the flow-induced vibrations. In the present study, numerical simulation of an energetically efficient active flow control strategy is proposed, for the control of wake vortices behind a circular cylinder at a low Reynolds number of 100. The fluid is assumed to be incompressible and Newtonian with negligible variation in properties. Reflectionally symmetric controllers are designed such that, they are located on a small sector of the cylinder over which, tangential sliding mode control is imparted. In the field of modern controls, proportional (P), integral (I) and differential (D) control strategies and their numerous combinations are extremely popular in industrial practice. To impart suitable control actuation, the vertically varying lift force on the circular cylinder, is synthesised for the construction of an error term. Four different types of controllers considered in the present study are, P, I, PI and PID. These controllers are evaluated for their energetic efficiency and performance. A linear quadratic optimal control problem is formulated, to minimise the cost functional. By performing detailed simulations, it was observed that, the system is energetically efficient, even when the twin eddies are still persisting behind the circular cylinder. To assess the adaptability of the controllers, the actuators were switched on and off to study their dynamic response.

  14. Observations of the stratorotational instability in rotating concentric cylinders

    NASA Astrophysics Data System (ADS)

    Ibanez, Ruy; Swinney, Harry L.; Rodenborn, Bruce

    2016-09-01

    We study the stability of density stratified flow between corotating vertical cylinders with rotation rates Ωo<Ωi and radius ratio ri/ro=0.877 , where subscripts o and i refer to the outer and inner cylinders. Just as in stellar and planetary accretion disks, the flow has rotation, anticyclonic shear, and a stabilizing density gradient parallel to the rotation axis. The primary instability of the laminar state leads not to axisymmetric Taylor vortex flow but to a nonaxisymmetric stratorotational instability (SRI). The present work extends the range of Reynolds numbers and buoyancy frequencies [N =√{(-g /ρ )(∂ ρ /∂ z ) }] examined in previous experiments. We present the first experimental results for the axial wavelength λ of the instability as a function of the internal Froude number, Fr=Ωi/N ; λ increases by nearly an order of magnitude over the range of Fr examined. For small outer cylinder Reynolds number, the SRI occurs for inner inner Reynolds number larger than for the axisymmetric Taylor vortex flow (i.e., the SRI is more stable). For somewhat larger outer Reynolds numbers the SRI occurs for smaller inner Reynolds numbers than Taylor vortex flow and even below the Rayleigh stability line for an inviscid fluid. Shalybkov and Rüdiger [Astron. Astrophys. 438, 411 (2005), 10.1051/0004-6361:20042492] proposed that the laminar state of a stably stratified rotating shear flow should be stable for Ωo/Ωi>ri/ro , but we find that this stability criterion is violated for N sufficiently large. At large Reynolds number the primary instability is not the SRI but a previously unreported nonperiodic state that mixes the fluid.

  15. Magnetohydrodynamic flow of Casson fluid over a stretching cylinder

    NASA Astrophysics Data System (ADS)

    Tamoor, M.; Waqas, M.; Khan, M. Ijaz; Alsaedi, Ahmed; Hayat, T.

    Here the Newtonian heating characteristics in MHD flow of Casson liquid induced by stretched cylinder moving with linear velocity is addressed. Consideration of dissipation and Joule heating characterizes the process of heat transfer. Applied electric and induced magnetic fields are not considered. Magnetic Reynolds number is low. The convenient transformation yields nonlinear problems which are solved for the convergent solutions. Convergence region is determined for the acquired solutions. Parameters highlighting for velocity and temperature are graphyically discussed. Numerical values of skin friction and Nusselt number are also presented in the tabular form. Present analysis reveals that velocity and thermal fields have reverse behavior for larger Hartman number. Moreover curvature parameter has similar influence on the velocity, temperature, skin friction and Nusselt number.

  16. Breached cylinder incident at the Portsmouth gaseous diffusion plant

    SciTech Connect

    Boelens, R.A.

    1991-12-31

    On June 16, 1990, during an inspection of valves on partially depleted product storage cylinders, a 14-ton partially depleted product cylinder was discovered breached. The cylinder had been placed in long-term storage in 1977 on the top row of Portsmouth`s (two rows high) storage area. The breach was observed when an inspector noticed a pile of green material along side of the cylinder. The breach was estimated to be approximately 8- inches wide and 16-inches long, and ran under the first stiffening ring of the cylinder. During the continuing inspection of the storage area, a second 14-ton product cylinder was discovered breached. This cylinder was stacked on the bottom row in the storage area in 1986. This breach was also located adjacent to a stiffening ring. This paper will discuss the contributing factors of the breaching of the cylinders, the immediate response, subsequent actions in support of the investigation, and corrective actions.

  17. Flow mediated interactions between two cylinders at finite Re numbers

    NASA Astrophysics Data System (ADS)

    Gazzola, Mattia; Mimeau, Chloe; Tchieu, Andrew A.; Koumoutsakos, Petros

    2012-04-01

    We present simulations of two interacting moving cylinders immersed in a two-dimensional incompressible, viscous flow. Simulations are performed by coupling a wavelet-adapted, remeshed vortex method with the Brinkman penalization and projection approach. This method is validated on benchmark problems and applied to simulations of a master-slave pair of cylinders. The master cylinder's motion is imposed and the slave cylinder is let free to respond to the flow. We study the relative role of viscous and inertia effects in the cylinders interactions and identify related sharp transitions in the response of the slave. The observed differences in the behavior of cylinders with respect to corresponding potential flow simulations are discussed. In addition, it is observed that in certain situations the finite size of the slave cylinders enhances the transport so that the cylinders are advected more effectively than passive tracers placed, respectively, at the same starting position.

  18. 21 CFR 886.1840 - Simulatan (including crossed cylinder).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... given object is clearly in focus, as the examiner uses different lenses). (b) Classification. Class I... cylinder). (a) Identification. A simulatan (including crossed cylinder) is a device that is a set of...

  19. 21 CFR 886.1840 - Simulatan (including crossed cylinder).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... given object is clearly in focus, as the examiner uses different lenses). (b) Classification. Class I... cylinder). (a) Identification. A simulatan (including crossed cylinder) is a device that is a set of...

  20. Nondestructive relative permittivity and loss tangent measurements using a split-cylinder resonator

    NASA Astrophysics Data System (ADS)

    Janezic, Michael Daniel

    To keep pace with the expanding wireless and electronics industries, manufacturers are developing innovative materials for improving system performance, and there is a critical need to accurately characterize the electrical properties of these new materials at microwave frequencies. To address this need, this thesis develops a nondestructive method for measuring the relative permittivity and loss tangent of dielectric substrates using a split-cylinder resonator. Three theoretical models for the split-cylinder resonator are derived using mode-matching, least-squares boundary residual, and Hankel-transform methods, from which one can calculate the relative permittivity and loss tangent of a dielectric substrate from measurements of the split-cylinder resonator's TE0np resonant frequency and quality factor. Each of these models has several advantages over previously published models. First, the accuracy of the relative permittivity measurement is increased because each model accurately models the fringing fields that extend beyond the cylindrical-cavity sections. Second, to increase the accuracy of the loss tangent measurement, each model accurately separates the conductive metal losses of the split-cylinder resonator from the dielectric losses of the substrate. Finally, in contrast to previous models for the split-cylinder resonator that use only the TE011 resonant mode, each of the new models include the higher-order TE0np resonant modes, thereby broadening the frequency range over which one can make relative permittivity and loss tangent measurements. In a comparison of the three models, the mode-matching method was found to be superior on the basis of measurement accuracy and computational speed. Relative permittivity and loss tangent measurements for several dielectric materials are performed using a split-cylinder resonator and are in good agreement with measurements made using a circular-cylindrical cavity, split-post resonator, and dielectric post resonator

  1. Stability analysis of cylinders with circular cutouts

    NASA Technical Reports Server (NTRS)

    Almroth, B. O.; Brogan, F. A.; Marlowe, M. B.

    1973-01-01

    The stability of axially compressed cylinders with circular cutouts is analyzed numerically. An extension of the finite-difference method is used which removes the requirement that displacement components be defined in the directions of the grid lines. The results of this nonlinear analysis are found to be in good agreement with earlier experimental results.

  2. Frequency spectra of laminated piezoelectric cylinders

    NASA Astrophysics Data System (ADS)

    Siao, J. C.-T.; Dong, S. B.; Song, J.

    1994-07-01

    A finite-element method is presented for determining the vibrational characteristics of a circular cylinder composed of bonded piezoelectric layers. Finite-element modeling occurs in the radial direction only using quadratic polynomials and the variationally derived partial differential equations are functions of the hoop and axial coordinates (theta, z) and time t. Using solution form Q exp (i(xi(z) + n(theta) + (omega)t)), with Q as the nodal amplitudes, leads to an algebraic eigensystem where any one of the three parameters (n, xi, omega), the circumferential or axial wave number or natural frequency, can act as the eigenvalue. Integer values always are assigned to n, leaving two possible eigenvalue problems. With omega as the eigenvalue and real values assigned to xi, the solutions represent propagating waves or harmonic standing vibrations in an infinite cylinder. When xi is the eigenvalue and real values assigned to omega, this eigensystem admits both real and complex eigendata. Real xi's represent propagating waves or harmonic standing vibrations as noted before. Complex conjugate pairs of xi 's describe end vibrations, which arise when an incident wave impinges upon a free end of a cylindrical bar. They are standing waves whose amplitudes decay sinusoidally or exponentially from the free end into the interior. Two examples are given to illustrate the method of analysis, viz., a solid piezoelectric cylinder of PZT-4 ceramic material and a two-layer cylinder of PZT-4 covering an isotropic material.

  3. Beam impedance of a split cylinder

    SciTech Connect

    Lambertson, G.

    1990-04-01

    A common geometry for position electrodes at moderately low frequencies is the capacitive pickup consisting of a diagonally- divided cylinder that encloses the beam trajectory. For the simplified system here, a relatively direct approach will given the longitudinal and transverse beam impedances (Z{parallel}and Z{perpendicular}) at low frequencies. This paper discusses the determination of this impedance.

  4. Laminar flow past a rotating circular cylinder

    NASA Astrophysics Data System (ADS)

    Kang, Sangmo; Choi, Haecheon; Lee, Sangsan

    1999-11-01

    The present study numerically investigates two-dimensional laminar flow past a circular cylinder rotating with a constant angular velocity, for the purpose of controlling vortex shedding and understanding the underlying flow mechanism. Numerical simulations are performed for flows with Re=60, 100, and 160 in the range of 0⩽α⩽2.5, where α is the circumferential speed at the cylinder surface normalized by the free-stream velocity. Results show that the rotation of a cylinder can suppress vortex shedding effectively. Vortex shedding exists at low rotational speeds and completely disappears at α>αL, where αL is the critical rotational speed which shows a logarithmic dependence on Re. The Strouhal number remains nearly constant regardless of α while vortex shedding exists. With increasing α, the mean lift increases linearly and the mean drag decreases, which differ significantly from those predicted by the potential flow theory. On the other hand, the amplitude of lift fluctuation stays nearly constant with increasing α (<αL), while that of drag fluctuation increases. Further studies from the instantaneous flow fields demonstrate again that the rotation of a cylinder makes a substantial effect on the flow pattern.

  5. Pulsatile flow past a single oscillating cylinder

    NASA Astrophysics Data System (ADS)

    Seda, Robinson; Qamar, Adnan; Bull, Joseph

    2010-11-01

    The potential for oscillating fibers to modify flow within a new artificial lung design is first examined in the present fundamental fluid mechanics study of flow past a single oscillating cylinder. This new design is intended to provide better gas exchange through vorticity enhancement by oscillating microfibers (cylinders) in a pulsatile flow environment. The Keulegan-Carpenter number (Kc=Uo/Dφc) was used to describe the frequency of the oscillating cylinder (φc) while the pulsatile free stream velocity was fixed by imposing φ/Kc=1 for all cases investigated. The parameters investigated in this study were amplitude of oscillation (0.5Dcylinder oscillating frequency matching the vortex shedding frequency) was found when KC=1 for all cases. A jump in the drag coefficient was observed and attributed to this operating regime. These results suggest that this new design of the TAL could potentially enhance gas exchange through oscillation of the microfibers with a decrease in the drag coefficient if operating far from the lock-in regime. This work was supported by NIH grants R01HL69420 and R01HL089043.

  6. Stationary Flux in Mesoscopic Noisy Cylinders

    NASA Astrophysics Data System (ADS)

    Dajka, J.; Łuczka, J.; Szopa, M.

    2003-07-01

    The aim of this paper is to investigate the existence of the stationary states of current in the mesoscopic cylinder. The dynamics of the flux is governed by a stochastic differential equation. We discuss both the influence of equilibrium (thermal) and non-equilibrium noise sources.

  7. Rotating Cylinder Treatment System Demonstration (Presentation)

    EPA Science Inventory

    In August 2008, a rotating cylinder treatment system (RCTSTM) demonstration was conducted near Gladstone, CO. The RCTSTM is a novel technology developed to replace the aeration/oxidation and mixing components of a conventional lime precipitation treatment s...

  8. Changes in the electrical properties of pure and doped polymers under the influence of small doses of X-rays

    NASA Astrophysics Data System (ADS)

    Mahmoud, S. A.; Madi, N. K.; Kassem, M. E.; El-Khatib, A.

    A study has been made of the temperature dependence of the d.c. conductivity of pure and borated low density polyethylene LDPE (4% and 8% borax). The above calculations were carried out before and after X-ray irradiation. The irradiation dose was varied from 0 to 1000 rad. The d.c. electrical conductivity of Polyvinyl chloride (PVC) and perspex was measured as a function of temperature ranging from 20°C to 100°C. These samples were irradiated with X-rays of dose 200 rad. The variation of the d.c. conductivity of the treated samples versus temperature was investigated. The results reveal that the d.c. conductivity of LDPE is highly affected by radiation and/or dopant. In addition, the sensitivity of the explored polymers to X-ray irradiation is strongly dependent on its chemical nature.

  9. Computation of Far-Field Noise from Vortex Shedding Behind a Circular Cylinder at Low Reynolds Numbers

    NASA Astrophysics Data System (ADS)

    Choi, H.; You, D.; Choi, M.-R.; Kang, S.-H.

    1996-11-01

    Laminar vortex sheddings behind a circular cylinder with and without splitter plates attached to the cylinder at low Reynolds numbers are simulated by solving the unsteady incompressible Navier-Stokes equations. The Strouhal number, lift and drag rapidly change with the length of the splitter plate. Far-field noise from the vortex shedding behind the cylinder is computed using the Curle's formulation of the Lighthill acoustic analogy. The acoustic source functions are obtained from the computed near-field velocity and pressure. Numerical results show that the volume quadrupole noise is small at a low Mach number, compared to the surface dipole noise from the cylinder. Variations of the far-field noise characteristics with respect to the splitter plate are being investigated and will be shown in the final presentation. ^* Supported by KOSEF under Contract No. 961-1009-075-2

  10. Ignition study of a petrol/CNG single cylinder engine

    NASA Astrophysics Data System (ADS)

    Khan, N.; Saleem, Z.; Mirza, A. A.

    2005-11-01

    Benefits of laser ignition over the electrical ignition system for Compressed Natural Gas (CNG) engines have fuelled automobile industry and led to an extensive research on basic characteristics to switch over to the emerging technologies. This study was undertaken to determine the electrical and physical characteristics of the electric spark ignition of single cylinder petrol/CNG engine to determine minimum ignition requirements and timeline of ignition events to use in subsequent laser ignition study. This communication briefly reviews the ongoing research activities and reports the results of this experimental study. The premixed petrol and CNG mixtures were tested for variation of current and voltage characteristics of the spark with speed of engine. The current magnitude of discharge circuit was found to vary linearly over a wide range of speed but the stroke to stroke fire time was found to vary nonlinearly. The DC voltage profiles were observed to fluctuate randomly during ignition process and staying constant in rest of the combustion cycle. Fire to fire peaks of current amplitudes fluctuated up to 10% of the peak values at constant speed but increased almost linearly with increase in speed. Technical barriers of laser ignition related to threshold minimum ignition energy, inter-pulse durations and firing sequence are discussed. Present findings provide a basic initiative and background information for designing suitable timeline algorithms for laser ignited leaner direct injected CNG engines.

  11. 77 FR 37384 - High Pressure Steel Cylinders From the People's Republic of China: Countervailing Duty Order

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-21

    ... International Trade Administration High Pressure Steel Cylinders From the People's Republic of China... duty order on high pressure steel cylinders (``steel cylinders'') from the People's Republic of China.... See High Pressure Steel Cylinders From the People's Republic of China: Final...

  12. Failure of Non-Circular Composite Cylinders

    NASA Technical Reports Server (NTRS)

    Hyer, M. W.

    2004-01-01

    In this study, a progressive failure analysis is used to investigate leakage in internally pressurized non-circular composite cylinders. This type of approach accounts for the localized loss of stiffness when material failure occurs at some location in a structure by degrading the local material elastic properties by a certain factor. The manner in which this degradation of material properties takes place depends on the failure modes, which are determined by the application of a failure criterion. The finite-element code STAGS, which has the capability to perform progressive failure analysis using different degradation schemes and failure criteria, is utilized to analyze laboratory scale, graphite-epoxy, elliptical cylinders with quasi-isotropic, circumferentially-stiff, and axially-stiff material orthotropies. The results are divided into two parts. The first part shows that leakage, which is assumed to develop if there is material failure in every layer at some axial and circumferential location within the cylinder, does not occur without failure of fibers. Moreover before fibers begin to fail, only matrix tensile failures, or matrix cracking, takes place, and at least one layer in all three cylinders studied remain uncracked, preventing the formation of a leakage path. That determination is corroborated by the use of different degradation schemes and various failure criteria. Among the degradation schemes investigated are the degradation of different engineering properties, the use of various degradation factors, the recursive or non-recursive degradation of the engineering properties, and the degradation of material properties using different computational approaches. The failure criteria used in the analysis include the noninteractive maximum stress criterion and the interactive Hashin and Tsai-Wu criteria. The second part of the results shows that leakage occurs due to a combination of matrix tensile and compressive, fiber tensile and compressive, and inplane

  13. Nonlinear bending and collapse analysis of a poked cylinder and other point-loaded cylinders

    SciTech Connect

    Sobel, L.H.

    1983-06-01

    This paper analyzes the geometrically nonlinear bending and collapse behavior of an elastic, simply supported cylindrical shell subjected to an inward-directed point load applied at midlength. The large displacement analysis results for this thin (R/t = 638) poked cylinder were obtained from the STAGSC-1 finite element computer program. STAGSC-1 results are also presented for two other point-loaded shell problems: a pinched cylinder (R/t = 100), and a venetian blind (R/t = 250).

  14. Investigation of breached depleted UF{sub 6} cylinders

    SciTech Connect

    DeVan, J.H.

    1991-12-31

    In June 1990, during a three-site inspection of cylinders being used for long-term storage of solid depleted UF{sub 6}, two 14-ton cylinders at Portsmouth, Ohio, were discovered with holes in the barrel section of the cylinders. An investigation team was immediately formed to determine the cause of the failures and their impact on future storage procedures and to recommend corrective actions. Subsequent investigation showed that the failures most probably resulted from mechanical damage that occurred at the time that the cylinders had been placed in the storage yard. In both cylinders evidence pointed to the impact of a lifting lug of an adjacent cylinder near the front stiffening ring, where deflection of the cylinder could occur only by tearing the cylinder. The impacts appear to have punctured the cylinders and thereby set up corrosion processes that greatly extended the openings in the wall and obliterated the original crack. Fortunately, the reaction products formed by this process were relatively protective and prevented any large-scale loss of uranium. The main factors that precipitated the failures were inadequate spacing between cylinders and deviations in the orientations of lifting lugs from their intended horizontal position. After reviewing the causes and effects of the failures, the team`s principal recommendation for remedial action concerned improved cylinder handling and inspection procedures. Design modifications and supplementary mechanical tests were also recommended to improve the cylinder containment integrity during the stacking operation.

  15. 46 CFR 197.338 - Compressed gas cylinders.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Compressed gas cylinders. 197.338 Section 197.338... STANDARDS GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.338 Compressed gas cylinders. Each compressed gas cylinder must— (a) Be stored in a ventilated area; (b) Be protected from excessive heat;...

  16. 30 CFR 57.16005 - Securing gas cylinders.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Securing gas cylinders. 57.16005 Section 57.16005 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL... Storage and Handling § 57.16005 Securing gas cylinders. Compressed and liquid gas cylinders shall...

  17. 46 CFR 197.338 - Compressed gas cylinders.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Compressed gas cylinders. 197.338 Section 197.338... STANDARDS GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.338 Compressed gas cylinders. Each compressed gas cylinder must— (a) Be stored in a ventilated area; (b) Be protected from excessive heat;...

  18. 30 CFR 57.16005 - Securing gas cylinders.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Securing gas cylinders. 57.16005 Section 57.16005 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL... Storage and Handling § 57.16005 Securing gas cylinders. Compressed and liquid gas cylinders shall...

  19. 30 CFR 56.16005 - Securing gas cylinders.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Securing gas cylinders. 56.16005 Section 56.16005 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL... and Handling § 56.16005 Securing gas cylinders. Compressed and liquid gas cylinders shall be...

  20. 30 CFR 56.16005 - Securing gas cylinders.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Securing gas cylinders. 56.16005 Section 56.16005 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL... and Handling § 56.16005 Securing gas cylinders. Compressed and liquid gas cylinders shall be...

  1. 46 CFR 197.338 - Compressed gas cylinders.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Compressed gas cylinders. 197.338 Section 197.338... STANDARDS GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.338 Compressed gas cylinders. Each compressed gas cylinder must— (a) Be stored in a ventilated area; (b) Be protected from excessive heat;...

  2. 49 CFR 176.92 - Cylinders laden in vehicles.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Requirements for Transport Vehicles Loaded With Hazardous Materials and Transported on Board Ferry Vessels § 176.92 Cylinders laden in vehicles. Any cylinder of Class 2 (compressed gas) material which is... 49 Transportation 2 2014-10-01 2014-10-01 false Cylinders laden in vehicles. 176.92 Section...

  3. 49 CFR 176.92 - Cylinders laden in vehicles.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Requirements for Transport Vehicles Loaded With Hazardous Materials and Transported on Board Ferry Vessels § 176.92 Cylinders laden in vehicles. Any cylinder of Class 2 (compressed gas) material which is... 49 Transportation 2 2012-10-01 2012-10-01 false Cylinders laden in vehicles. 176.92 Section...

  4. 49 CFR 176.92 - Cylinders laden in vehicles.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Requirements for Transport Vehicles Loaded With Hazardous Materials and Transported on Board Ferry Vessels § 176.92 Cylinders laden in vehicles. Any cylinder of Class 2 (compressed gas) material which is... 49 Transportation 2 2011-10-01 2011-10-01 false Cylinders laden in vehicles. 176.92 Section...

  5. 49 CFR 176.92 - Cylinders laden in vehicles.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Requirements for Transport Vehicles Loaded With Hazardous Materials and Transported on Board Ferry Vessels § 176.92 Cylinders laden in vehicles. Any cylinder of Class 2 (compressed gas) material which is... 49 Transportation 2 2013-10-01 2013-10-01 false Cylinders laden in vehicles. 176.92 Section...

  6. 49 CFR 176.92 - Cylinders laden in vehicles.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Requirements for Transport Vehicles Loaded With Hazardous Materials and Transported on Board Ferry Vessels § 176.92 Cylinders laden in vehicles. Any cylinder of Class 2 (compressed gas) material which is... 49 Transportation 2 2010-10-01 2010-10-01 false Cylinders laden in vehicles. 176.92 Section...

  7. Pistons and Cylinders Made of Carbon-Carbon Composite Materials

    NASA Technical Reports Server (NTRS)

    Rivers, H. Kevin (Inventor); Ransone, Philip O. (Inventor); Northam, G. Burton (Inventor); Schwind, Francis A. (Inventor)

    2000-01-01

    An improved reciprocating internal combustion engine has a plurality of engine pistons, which are fabricated from carbon-carbon composite materials, in operative association with an engine cylinder block, or an engine cylinder tube, or an engine cylinder jug, all of which are also fabricated from carbon-carbon composite materials.

  8. 49 CFR 174.201 - Class 2 (gases) material cylinders.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 2 2014-10-01 2014-10-01 false Class 2 (gases) material cylinders. 174.201... RAIL Detailed Requirements for Class 2 (Gases) Materials § 174.201 Class 2 (gases) material cylinders. (a) Except as provided in paragraphs (b) and (c) of this section, cylinders containing Class 2...

  9. 49 CFR 174.201 - Class 2 (gases) material cylinders.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Class 2 (gases) material cylinders. 174.201... RAIL Detailed Requirements for Class 2 (Gases) Materials § 174.201 Class 2 (gases) material cylinders. (a) Except as provided in paragraphs (b) and (c) of this section, cylinders containing Class 2...

  10. 49 CFR 174.201 - Class 2 (gases) material cylinders.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 2 2012-10-01 2012-10-01 false Class 2 (gases) material cylinders. 174.201... RAIL Detailed Requirements for Class 2 (Gases) Materials § 174.201 Class 2 (gases) material cylinders. (a) Except as provided in paragraphs (b) and (c) of this section, cylinders containing Class 2...

  11. 49 CFR 174.201 - Class 2 (gases) material cylinders.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 2 2013-10-01 2013-10-01 false Class 2 (gases) material cylinders. 174.201... RAIL Detailed Requirements for Class 2 (Gases) Materials § 174.201 Class 2 (gases) material cylinders. (a) Except as provided in paragraphs (b) and (c) of this section, cylinders containing Class 2...

  12. 49 CFR 174.201 - Class 2 (gases) material cylinders.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 2 2011-10-01 2011-10-01 false Class 2 (gases) material cylinders. 174.201... RAIL Detailed Requirements for Class 2 (Gases) Materials § 174.201 Class 2 (gases) material cylinders. (a) Except as provided in paragraphs (b) and (c) of this section, cylinders containing Class 2...

  13. 58. (Credit JTL) View looking northeast across steam cylinders of ...

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

    58. (Credit JTL) View looking northeast across steam cylinders of Allis-Chalmers pumping engine. High-pressure cylinder is in foreground, low-pressure cylinder in background with part of Corliss valve gear visible. - McNeil Street Pumping Station, McNeil Street & Cross Bayou, Shreveport, Caddo Parish, LA

  14. 76 FR 38697 - High Pressure Steel Cylinders From China

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-01

    ... COMMISSION High Pressure Steel Cylinders From China Determinations On the basis of the record \\1\\ developed... injured by reason of imports from China of high pressure steel cylinders, provided for in subheading 7311... pressure steel cylinders from China. Accordingly, effective May 11, 2011, the Commission...

  15. 30 CFR 56.16006 - Protection of gas cylinder valves.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Storage and Handling § 56.16006 Protection of gas cylinder valves. Valves on compressed gas cylinders... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Protection of gas cylinder valves. 56.16006 Section 56.16006 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL...

  16. 30 CFR 57.16006 - Protection of gas cylinder valves.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Storage and Handling § 57.16006 Protection of gas cylinder valves. Valves on compressed gas cylinders... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Protection of gas cylinder valves. 57.16006 Section 57.16006 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL...

  17. Global aerodynamic instability of twin cylinders in cross flow

    NASA Astrophysics Data System (ADS)

    Alam, Md. Mahbub; Meyer, J. P.

    2013-08-01

    This paper comprises an in-depth physical discussion of the flow-induced vibration of two circular cylinders in view of the time-mean lift force on stationary cylinders and interaction mechanisms. The gap-spacing ratio T/D is varied from 0.1 to 5 and the attack angle α from 0° to 180° where T is the gap width between the cylinders and D is the diameter of a cylinder. Mechanisms of interaction between two cylinders are discussed based on time-mean lift, fluctuating lift, flow structures and flow-induced responses. The whole regime is classified into seven interaction regimes, i.e., no interaction regime; boundary layer and cylinder interaction regime; shear-layer/wake and cylinder interaction regime; shear-layer and shear-layer interaction regime; vortex and cylinder interaction regime; vortex and shear-layer interaction regime; and vortex and vortex interaction regime. Though a single non-interfering circular cylinder does not correspond to a galloping following quasi-steady galloping theory, two circular cylinders experience violent galloping vibration due to shear-layer/wake and cylinder interaction as well as boundary layer and cylinder interaction. A larger magnitude of fluctuating lift communicates to a larger amplitude vortex excitation.

  18. 30 CFR 56.4601 - Oxygen cylinder storage.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Oxygen cylinder storage. 56.4601 Section 56.4601 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL... Control Welding/cutting/compressed Gases § 56.4601 Oxygen cylinder storage. Oxygen cylinders shall not...

  19. 30 CFR 57.4601 - Oxygen cylinder storage.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Oxygen cylinder storage. 57.4601 Section 57.4601 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL... and Control Welding/cutting/compressed Gases § 57.4601 Oxygen cylinder storage. Oxygen cylinders...

  20. 30 CFR 56.4601 - Oxygen cylinder storage.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Oxygen cylinder storage. 56.4601 Section 56.4601 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL... Control Welding/cutting/compressed Gases § 56.4601 Oxygen cylinder storage. Oxygen cylinders shall not...

  1. 30 CFR 56.4601 - Oxygen cylinder storage.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Oxygen cylinder storage. 56.4601 Section 56.4601 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL... Control Welding/cutting/compressed Gases § 56.4601 Oxygen cylinder storage. Oxygen cylinders shall not...

  2. 30 CFR 57.4601 - Oxygen cylinder storage.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Oxygen cylinder storage. 57.4601 Section 57.4601 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL... and Control Welding/cutting/compressed Gases § 57.4601 Oxygen cylinder storage. Oxygen cylinders...

  3. 30 CFR 57.4601 - Oxygen cylinder storage.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Oxygen cylinder storage. 57.4601 Section 57.4601 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL... and Control Welding/cutting/compressed Gases § 57.4601 Oxygen cylinder storage. Oxygen cylinders...

  4. 30 CFR 57.4601 - Oxygen cylinder storage.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Oxygen cylinder storage. 57.4601 Section 57.4601 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL... and Control Welding/cutting/compressed Gases § 57.4601 Oxygen cylinder storage. Oxygen cylinders...

  5. 30 CFR 57.4601 - Oxygen cylinder storage.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Oxygen cylinder storage. 57.4601 Section 57.4601 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL... and Control Welding/cutting/compressed Gases § 57.4601 Oxygen cylinder storage. Oxygen cylinders...

  6. 30 CFR 56.4601 - Oxygen cylinder storage.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Oxygen cylinder storage. 56.4601 Section 56.4601 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL... Control Welding/cutting/compressed Gases § 56.4601 Oxygen cylinder storage. Oxygen cylinders shall not...

  7. 30 CFR 56.4601 - Oxygen cylinder storage.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Oxygen cylinder storage. 56.4601 Section 56.4601 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL... Control Welding/cutting/compressed Gases § 56.4601 Oxygen cylinder storage. Oxygen cylinders shall not...

  8. Vibroacoustic Response Data of Stiffened Panels and Cylinders

    NASA Technical Reports Server (NTRS)

    Cabell, Randolph; Klos, Jake; Buehrle, Ralph; Schiller, Noah

    2008-01-01

    NASA has collected vibroacoustic response data on a variety of complex, aerospace structures to support research into numerical modeling of such structures. This data is being made available to the modeling community to promote the development and validation of analysis methods for these types of structures. Existing data from two structures is described, as well as plans for a data set from a third structure. The first structure is a 1.22 m by 1.22 m stiffened aluminum panel, typical of a commercial aircraft sidewall section. The second is an enclosed, stiffened aluminum cylinder, approximately 3.66 m long and 1.22 m in diameter, constructed to resemble a small aircraft fuselage with no windows and a periodic structure. The third structure is a filament-wound composite cylinder with composite stiffeners. Numerous combinations of excitation and response variables were measured on the structures, including: shaker excitation; diffuse acoustic field; velocity response from a laser vibrometer; intensity scans; and point acceleration.

  9. Circular cylinders with soft porous cover for flow noise reduction

    NASA Astrophysics Data System (ADS)

    Geyer, Thomas F.; Sarradj, Ennes

    2016-03-01

    The use of porous materials is one of several approaches to passively control or minimize the generation of flow noise. In order to investigate the possible reduction of noise from struts and other protruding parts (for example components of the landing gear or pantographs), acoustic measurements were taken in a small aeroacoustic wind tunnel on a set of circular cylinders with a soft porous cover. The aim of this study was to identify those materials that result in the best noise reduction, which refers to both tonal noise and broadband noise. The porous covers were characterized by their air flow resistivity, a parameter describing the permeability of an open-porous material. The results show that materials with low air flow resistivities lead to a noticeable flow noise reduction. Thereby, the main effect of the porous cylinder covers is that the spectral peak of the aeolian tone due to vortex shedding appears much narrower, but is not suppressed completely. Based on the measurement results, a basic model for the estimation of the total peak level of the aeolian tone was derived. In addition to the minimization of the vortex shedding noise, a reduction of broadband noise can be observed, especially at higher Reynolds numbers. The noise reduction increases with decreasing air flow resistivity of the porous covers, which means that materials that are highly permeable to air result in the best noise reduction.

  10. Dynamical mechanism for coercivity tunability in the electrically controlled FePt perpendicular films with small grain size

    SciTech Connect

    Feng, Chun Li, Xujing; Jiang, Yong; Yu, Guanghua; Yang, Meiyin; Gong, Kui; Li, Baohe

    2014-01-14

    This article reports property manipulations and related dynamical evolution in electromigration controlled FePt perpendicular films. Through altering voltage and treatment time of the power supply applied on the films, electronic momentum was fleetly controlled to manipulate the kinetic energy of Fe and Pt atoms based on momentum exchanges. The electromigration control behavior was proven to cause steerable ordering degree and grain growth in the films without thermal treatment. Processed FePt films with small grain size, high magnetocrystalline anisotropy, and controllable coercivity can be easily obtained. The results provide a novel method for tuning magnetic properties of other L1{sub 0} structured films.

  11. Electric vehicles

    NASA Astrophysics Data System (ADS)

    1990-03-01

    Quiet, clean, and efficient, electric vehicles (EVs) may someday become a practical mode of transportation for the general public. Electric vehicles can provide many advantages for the nation's environment and energy supply because they run on electricity, which can be produced from many sources of energy such as coal, natural gas, uranium, and hydropower. These vehicles offer fuel versatility to the transportation sector, which depends almost solely on oil for its energy needs. Electric vehicles are any mode of transportation operated by a motor that receives electricity from a battery or fuel cell. EVs come in all shapes and sizes and may be used for different tasks. Some EVs are small and simple, such as golf carts and electric wheel chairs. Others are larger and more complex, such as automobile and vans. Some EVs, such as fork lifts, are used in industries. In this fact sheet, we will discuss mostly automobiles and vans. There are also variations on electric vehicles, such as hybrid vehicles and solar-powered vehicles. Hybrid vehicles use electricity as their primary source of energy, however, they also use a backup source of energy, such as gasoline, methanol or ethanol. Solar-powered vehicles are electric vehicles that use photovoltaic cells (cells that convert solar energy to electricity) rather than utility-supplied electricity to recharge the batteries. These concepts are discussed.

  12. Mass transfer from a circular cylinder: Effects of flow unsteadiness and ""slight" nonuniformities

    NASA Astrophysics Data System (ADS)

    Marziale, M. L.

    The effect of periodic variations in the angle of the flow incident to a turbine blade on its leading edge heat load was investigated measuring a circular cylinder oscillating rotationally in a uniform steady flow A stationary cylinder was used and the transfer rate was measured for Re = 75,000 to 110,000 and turbulence levels from .34% to 4.9%. The accuracy and repeatability of the developed mass transfer technique is about + or - 2%, a large improvement over similar methods. Identical flow conditions were used when the cylinder was oscillated. A Strouhal number range from .0071 to .1406 was covered. Comparisons of the unsteady results indicate that the magnitude of the effect of oscillation is small and dependent on the incident turbulence conditions. Experiments were conducted in which a small amplitude periodic perturbation was superimposed on the mean flow by a woven wire grid. Spanwise traverses of the mean velocity and turbulence quantities and spanwise and circumferential traverses of the mass transfer rate on the cylinder were made. Although the perturbation was measured to be only .25% of the mean velocity and was buried in the stream's turbulence, disproportionately larger 15% variations in the spanwise transfer rate were observed.

  13. Performance of Air-cooled Engine Cylinders Using Blower Cooling

    NASA Technical Reports Server (NTRS)

    Schey, Oscar W; Ellerbrock, Herman H , Jr

    1936-01-01

    An investigation was made to obtain information on the minimum quantity of air and power required to cool conventional air cooled cylinders at various operating conditions when using a blower. The results of these tests show that the minimum power required for satisfactory cooling with an overall blower efficiency of 100 percent varied from 2 to 6 percent of the engine power depending on the operating conditions. The shape of the jacket had a large effect on the cylinder temperatures. Increasing the air speed over the front of the cylinder by keeping the greater part of the circumference of the cylinder covered by the jacket reduced the temperatures over the entire cylinder.

  14. Differential effect of auxin on in vivo extensibility of cortical cylinder and epidermis in pea internodes.

    PubMed

    Kutschera, U; Briggs, W R

    1987-08-01

    The effect of auxin indole-3-acetic acid (IAA) on growth and in vivo extensibility of third internode sections from red light grown pea seedlings (Pisum sativum L. cv Alaska) and the isolated tissues (cortex plus vascular tissue = cortical cylinder, and epidermis) was investigated. Living tissue was stretched at constant force (creep test) in a custom-built extensiometer. In the intact section, IAA-induced increase in total (E(tot)), elastic (E(el)), and plastic (E(pl)) extensibility is closely related to the growth rate. The extensibility of the cortical cylinder, measured immediately after peeling of intact sections incubated for 4 hours in IAA, is not increased by IAA. Epidermal strips, peeled from growing sections incubated in IAA, show a E(pl) increase, which is correlated to the growth rate of the intact segments. The isolated cortical cylinder expands in water; IAA has only a small growth-promoting effect. The extensibility of the cortical cylinder is not increased by IAA. Epidermal strips contract about 10% on isolation. When incubated in IAA, they do not elongate, but respond with an E(pl) increase. The amount of expansion of the cortical cylinder and contraction of the epidermis (tissue tension), measured immediately following excision and peeling, stays constant during IAA-induced growth of intact sections. The results support the hypothesis that IAA induces growth of the intact section by causing an E(pl) increase of the outer epidermal wall. The driving force comes from the expansion of the cortical cylinder which is under constant compression in the intact section.

  15. Forced motion and acoustic radiation of an elastic cylinder in axial flow

    NASA Astrophysics Data System (ADS)

    Manela, A.; Miloh, T.

    2012-07-01

    We study the forced motion and far-field acoustic radiation of an elastic cylinder subject to uniform axial flow and actuated at its upstream end by small-amplitude periodic displacement and rotation. The linearized problem is analysed under subcritical conditions of low nondimensional stream-flow velocity, ucylinder is aligned with the external flow. It is found that the forced motion at subcritical conditions is affected by the properties of the in vacuo system. A resonance is excited when the cylinder is actuated at one of its in vacuo eigenfrequencies, ωres, manifested by relatively large deflections. Fluid flow acts to regularize this behavior by transferring energy from the upstream driver to the fluid. The dynamical description is used as a source term in the formulation of the vibroacoustic problem. Assuming the cylinder is well-streamlined and neglecting the effect of vortex shedding, the far field sound is attributed directly to cylinder vibration. Acoustic radiation of a dipole type is found in the limit where the cylinder is acoustically compact. Following the dynamical description, it is shown that fluid flow reduces the sound level compared to that in the absence of mean flow, when actuation is applied close to ω=ωres. In addition, we demonstrate that far-field sound can be controlled by varying the actuation parameters. Analytical description of the dynamical and acoustic fields is obtained in the limit u≪1, and found in close agreement with the exact numerical solution up to u˜O(1). Discrepancies between the approximate and exact solutions are observed close to the resonance frequencies, and rationalized in terms of the strong fluid-structure coupling occurring when ω→ωres. At ω=ωres, a qualitative description of the effect of fluid stream flow on the system behavior is supplied.

  16. Unsteady Flowfield Around Tandem Cylinders as Prototype for Component Interaction in Airframe Noise

    NASA Technical Reports Server (NTRS)

    Khorrami, Meldi R.; Choudhari, Meelan M.; Jenkins, Luther N.; McGinley, Catherine B.

    2005-01-01

    Synergistic application of experiments and numerical simulations is crucial to understanding the underlying physics of airframe noise sources. The current effort is aimed at characterizing the details of the flow interaction between two cylinders in a tandem configuration. This setup is viewed to be representative of several component-level flow interactions that occur when air flows over the main landing gear of large civil transports. Interactions of this type are likely to have a significant impact on the noise radiation associated with the aircraft undercarriage. The paper is focused on two-dimensional, time-accurate flow simulations for the tandem cylinder configuration. Results of the unsteady Reynolds Averaged Navier-Stokes (URANS) computations with a two-equation turbulence model, at a Reynolds number of 0.166 million and a Mach number of 0.166, are presented. The experimental measurements of the same flow field are discussed in a separate paper by Jenkins, Khorrami, Choudhari, and McGinley (2005). Two distinct flow regimes of interest, associated with short and intermediate separation distances between the two cylinders, are considered. Emphasis is placed on understanding both time averaged and unsteady flow features between the two cylinders and in the wake of the rear cylinder. Predicted mean flow quantities and vortex shedding frequencies show reasonable agreement with the measured data for both cylinder spacings. Computations for short separation distance indicate decay of flow unsteadiness with time, which is not unphysical; however, the predicted sensitivity of mean lift coefficient to small angles of attack explains the asymmetric flowfield observed during the experiments.

  17. Radiation levels on empty cylinders containing heel material

    SciTech Connect

    Shockley, C.W.

    1991-12-31

    Empty UF{sub 6} cylinders containing heel material were found to emit radiation levels in excess of 200 mr/hr, the maximum amount stated in ORO-651. The radiation levels were as high as 335 mr/hr for thick wall (48X and 48Y) cylinders and 1050 mr/hr for thin wall (48G and 48H) cylinders. The high readings were found only on the bottom of the cylinders. These radiation levels exceeded the maximum levels established in DOT 49 CFR, Part 173.441 for shipment of cylinders. Holding periods of four weeks for thick-wall cylinders and ten weeks for thin-wall cylinders were established to allow the radiation levels to decay prior to shipment.

  18. The marginalization of "small is beautiful": Micro-hydroelectricity, common property, and the politics of rural electricity provision in Thailand

    NASA Astrophysics Data System (ADS)

    Greacen, Christopher Edmund

    electricity to PEA offers a mutually beneficial opportunity for the Thai public and for villagers, but one thus far thwarted by bureaucratic challenges. Explanations of renewable energy dissemination in countries with strong state involvement in rural electrification should borrow approaches from political economy concerning the ways in which politics and constellations of other factors eclipse rational economic behavior. At the village level, common pool resource theory reveals causal linkages between appliance use, equipment limitations, power quality, and equipment failures.

  19. Cylinder Flow Control Using Plasma Actuators

    NASA Astrophysics Data System (ADS)

    Kozlov, Alexey; Thomas, Flint

    2007-11-01

    In this study the results of flow control experiments utilizing single dielectric barrier discharge plasma actuators to control flow separation and unsteady vortex shedding from a circular cylinder in cross-flow are reported. Two optimized quartz dielectric plasma actuators mounted on the cylinder surface utilizing an improved saw-tooth waveform high-voltage generator allowed flow control at Reynolds number approaching supercritical. Using either steady or unsteady actuation, it is demonstrated that the plasma-induced surface blowing gives rise to a local Coanda effect that promotes the maintenance of flow attachment. PIV based flow fields and wake velocity profiles obtained with hot-wire anemometry show large reductions in vortex shedding, wake width and turbulence intensity.

  20. Micromagnetic behavior of electrodeposited cylinder arrays

    NASA Astrophysics Data System (ADS)

    Ross, C. A.; Hwang, M.; Shima, M.; Cheng, J. Y.; Farhoud, M.; Savas, T. A.; Smith, Henry I.; Schwarzacher, W.; Ross, F. M.; Redjdal, M.; Humphrey, F. B.

    2002-04-01

    Arrays of cylindrical magnetic particles have been made using interference lithography combined with electrodeposition. The cylinders are made from Ni, Co, CoP, or CoNi, with diameters of 57-180 nm, aspect ratios of 0.4-3, and array periods of 100-200 nm. The remanent states of the cylinders correspond to single-domain ``flower'' states or to magnetization vortices depending on the particle size and aspect ratio. Experimental data are in good agreement with a magnetic-state map calculated using a three-dimensional micromagnetic model, which shows the remanent state as a function of particle size and aspect ratio. The interactions between the particles, and their switching-field distribution, have been quantified.

  1. Bilateral symmetry breaking in nonlinear circular cylinders.

    PubMed

    Yuan, Lijun; Lu, Ya Yan

    2014-12-01

    Symmetry breaking is a common phenomenon in nonlinear systems, it refers to the existence of solutions that do not preserve the original symmetries of the underlying system. In nonlinear optics, symmetry breaking has been previously investigated in a number of systems, usually based on simplified model equations or temporal coupled mode theories. In this paper, we analyze the scattering of an incident plane wave by one or two circular cylinders with a Kerr nonlinearity, and show the existence of solutions that break a lateral reflection symmetry. Although symmetry breaking is a known phenomenon in nonlinear optics, it is the first time that this phenomenon was rigorously studied in simple systems with one or two circular cylinders.

  2. Upgraded Analytical Model of the Cylinder Test

    SciTech Connect

    Souers, P. Clark; Lauderbach, Lisa; Garza, Raul; Ferranti, Louis; Vitello, Peter

    2013-03-15

    A Gurney-type equation was previously corrected for wall thinning and angle of tilt, and now we have added shock wave attenuation in the copper wall and air gap energy loss. Extensive calculations were undertaken to calibrate the two new energy loss mechanisms across all explosives. The corrected Gurney equation is recommended for cylinder use over the original 1943 form. The effect of these corrections is to add more energy to the adiabat values from a relative volume of 2 to 7, with low energy explosives having the largest correction. The data was pushed up to a relative volume of about 15 and the JWL parameter ω was obtained directly. Finally, the total detonation energy density was locked to the v = 7 adiabat energy density, so that the Cylinder test gives all necessary values needed to make a JWL.

  3. Guided wave modes in porous cylinders: experimental results.

    PubMed

    Wisse, C J; Smeulders, D M J; van Dongen, M E H; Chao, G

    2002-09-01

    In this paper guided wave modes in porous media are investigated. A water-saturated porous cylinder is mounted in the test section of a shock tube. Between the porous sample and the wall of the shock tube a water-filled annulus exists. For very small annulus width, bulk waves are generated and one-dimensional modeling is sufficient. Otherwise two-dimensional effects become important and multiple guided wave modes occur. Using a newly developed traversable positioning system in the shock tube, the frequency-dependent phase velocities and damping coefficients in the 1-120 kHz frequency range were measured. Prony's method was used for data processing. Agreement was found between the experimental data and the two-dimensional modeling of the shock tube which was based on Biot's theory.

  4. DDES and IDDES of tandem cylinders.

    SciTech Connect

    Balakrishnan, R.; Garbaruk, A.; Shur, M.; Strelets, M.; Spalart, P.; New Technologies and Services - Russia; St.-Peterburg State Polytechnic Univ.; Boeing Commercial Airplanes

    2010-09-09

    The paper presents an overview of the authors contribution to the BANC-I Workshop on the flow past tandem cylinders (Category 2). It includes an outline of the simulation approaches, numerics, and grid used, the major results of the simulations, their comparison with available experimental data, and some preliminary conclusions. The effect of varying the spanwise period in the simulations is strong for some quantities, and not others.

  5. Compressive strength of axially loaded composite cylinders

    NASA Astrophysics Data System (ADS)

    Kollar, Laszlo P.; Springer, George C.; Spingarn, Jay; McColskey, J. D.

    1993-10-01

    Tests were performed to measure the failure loads of axially compressed glass-fiber-reinforced and graphite-fiber-reinforced composite cylinders. The data were compared with the results of a previous model, which was based on a three-dimensional stress analysis and the Tsai-Wu quadratic first-ply failure criterion. This model predicted the failure loads for glass-fiber-reinforced composites with good accuracy, but less accurately for failure loads of graphite-epoxy composites.

  6. Parabolic cylinder functions of large order

    NASA Astrophysics Data System (ADS)

    Jones, D. S.

    2006-06-01

    The asymptotic behaviour of parabolic cylinder functions of large real order is considered. Various expansions in terms of elementary functions are derived. They hold uniformly for the variable in appropriate parts of the complex plane. Some of the expansions are doubly asymptotic with respect to the order and the complex variable which is an advantage for computational purposes. Error bounds are determined for the truncated versions of the asymptotic series.

  7. Instability of flow around a rotating, semi-infinite cylinder

    NASA Astrophysics Data System (ADS)

    Derebail Muralidhar, Srikanth; Pier, Benoît; Scott, Julian F.

    2016-09-01

    Stability of flow around a rotating, semi-infinite cylinder placed in an axial stream is investigated. Assuming large Reynolds number, the basic flow is computed numerically as described by Derebail Muralidhar et al. [Proc. R. Soc. London, Ser. A 472, 20150850 (2016), 10.1098/rspa.2015.0850], while numerical solution of the local stability equations allows calculation of the modal growth rates and hence determination of flow stability or instability. The problem has three nondimensional parameters: the Reynolds number Re , the rotation rate S , and the axial location Z . Small amounts of rotation are found to strongly affect flow stability. This is the result of a nearly neutral mode of the nonrotating cylinder which controls stability at small S . Even small rotation can produce a sufficient perturbation that the mode goes from decaying to growing, with obvious consequences for stability. Without rotation, the flow is stable below a Reynolds number of about 1060 and also beyond a threshold Z . With rotation, no matter how small, instability is no longer constrained by a minimum Re nor a maximum Z . In particular, the critical Reynolds number goes to zero as Z →∞ , so the flow is always unstable at large enough axial distances from the nose. As Z is increased, the flow goes from stability at small Z to instability at large Z . If the critical Reynolds number is a monotonic decreasing function of Z , as it is for S between about 0.0045 and 5, there is a single boundary in Z , which separates the stable from the unstable part of the flow. On the other hand, when the critical Reynolds number is nonmonotonic, there can, depending on the choice of Re , be several such boundaries and flow stability switches more than once as Z is increased. Detailed results showing the critical Reynolds number as a function of Z for different rotation rates are given. We also obtain an asymptotic expansion of the critical Reynolds number at large Z and use perturbation theory to

  8. Analysis of mechanical joint in composite cylinder

    NASA Astrophysics Data System (ADS)

    Hong, C. S.; Kim, Y. W.; Park, J. S.

    Joining techniques of composite materials are of great interest in cylindrical structures as the application of composites is widely used for weight-sensitive structures. Little information for the mechanical fastening joint of the laminated shell structure is available in the literature. In this study, a finite element program, which was based on the first order shear deformation theory, was developed for the analysis of the mechanical joint in the laminated composite structure. The failure of the mechanical fastening joint for the laminated graphite/epoxy cylinder subject to internal pressure was analyzed by using the developed program. Modeling of the bolt head in the composite cylinder was studied, and the effect of steel reinforcement outside the composite cylinder on the failure was investigated. The stress component near the bolt head was influenced by the size of the bolt head. The failure load and the failure mode were dependent on the bolt diameter, the number of bolts, and fiber orientation. The failure load was constant when the edge distance exceeds three times the bolt diameter.

  9. Normalization and source separation of acoustic emission signals for condition monitoring and fault detection of multi-cylinder diesel engines

    NASA Astrophysics Data System (ADS)

    Wu, Weiliang; Lin, Tian Ran; Tan, Andy C. C.

    2015-12-01

    A signal processing technique is presented in this paper to normalize and separate the source of non-linear acoustic emission (AE) signals of a multi-cylinder diesel engine for condition monitoring applications and fault detection. The normalization technique presented in the paper overcomes the long-existing non-linearity problem of AE sensors so that responses measured by different AE sensors can be quantitatively analysed and compared. A source separation algorithm is also developed in the paper to separate the mixture of the normalized AE signals produced by a multi-cylinder diesel engine by utilising the system parameters (i.e., wave attenuation constant and the arrival time delay) of AE wave propagation determined by a standard pencil lead break test on the engine cylinder head. It is shown that the source separation algorithm is able to separate the signal interference of adjacent cylinders from the monitored cylinder once the wave attenuation constant and the arrival time delay along the propagation path are known. The algorithm is particularly useful in the application of AE technique for condition monitoring of small-size diesel engines where signal interference from the neighbouring cylinders is strong.

  10. A fast algorithm based on the domain decomposition method for scattering analysis of electrically large objects

    NASA Astrophysics Data System (ADS)

    Yin, Lei; Hong, Wei

    2002-01-01

    By combining the finite difference (FD) method with the domain decomposition method (DDM), a fast and rigorous algorithm is presented in this paper for the scattering analysis of extremely large objects. Unlike conventional methods, such as the method of moments (MOM) and FD method, etc., the new algorithm decomposes an original large domain into small subdomains and chooses the most efficient method to solve the electromagnetic (EM) equations on each subdomain individually. Therefore the computational complexity and scale are substantially reduced. The iterative procedure of the algorithm and the implementation of virtual boundary conditions are discussed in detail. During scattering analysis of an electrically large cylinder, the conformal band computational domain along the circumference of the cylinder is decomposed into sections, which results in a series of band matrices with very narrow band. Compared with the traditional FD method, it decreases the consumption of computer memory and CPU time from O(N2) to O(N/m) and O(N), respectively, where m is the number of subdomains and Nis the number of nodes or unknowns. Furthermore, this method can be easily applied for the analysis of arbitrary shaped cylinders because the subdomains can be divided into any possible form. On the other hand, increasing the number of subdomains will hardly increase the computing time, which makes it possible to analyze the EM scattering problems of extremely large cylinders only on a PC. The EM scattering by two-dimensional cylinders with maximum perimeter of 100,000 wavelengths is analyzed. Moreover, this method is very suitable for parallel computation, which can further promote the computational efficiency.

  11. Vortex-induced vibrations of a flexibly-mounted inclined cylinder

    NASA Astrophysics Data System (ADS)

    Jain, Anil; Modarres-Sadeghi, Yahya

    2013-11-01

    The majority of studies on vortex-induced vibrations of a flexibly-mounted rigid cylinder are for the cases where the flow direction is perpendicular to the long axis of the structure. However, in many engineering applications, such as cable stays in bridges and mooring lines of floating offshore wind turbines, the flow direction may not be perpendicular to the structure. To understand the vortex shedding behind a fixed inclined cylinder, the Independence Principle (IP) has been used. The IP assumes that an inclined cylinder behaves similarly to a normal-incidence case, if only the component of the free stream velocity normal to the cylinder axis is considered. The IP neglects the effect of the axial component of the flow, which seems reasonable for small angles of inclination, but not for large angles. In the present study, a series of experiments have been conducted on a flexibly-mounted rigid cylinder placed inclined to the oncoming flow with various angles of inclination (0°<θ<75°) in a range of Reynolds numbers from 500 to 4000 to investigate how the angle of inclination affects VIV. A rigid cylinder was mounted on springs, and air bearings were used to reduce the structural damping of the system. The system was placed in the test-section of a recirculating water tunnel and the crossflow displacements were measured at each flow velocity. Even at high angles of inclination, large-amplitude oscillations were observed. As the angle of inclination was increased, the lock-in range (the range of reduced flow velocities for which the cylinder oscillates with a large amplitude) started at a higher reduced velocity. When only the normal component of the oncoming flow was considered, the onset of lock-in was observed to be at the same normalized flow velocity for all angles of inclination except for 75°. However, the width of the lock-in region, its pattern, the maximum amplitude of oscillations and its corresponding normalized reduced velocity were not following

  12. Solvable critical dense polymers on the cylinder

    NASA Astrophysics Data System (ADS)

    Pearce, Paul A.; Rasmussen, Jørgen; Villani, Simon P.

    2010-02-01

    A lattice model of critical dense polymers is solved exactly on a cylinder with finite circumference. The model is the first member {\\cal LM}(1,2) of the Yang-Baxter integrable series of logarithmic minimal models. The cylinder topology allows for non-contractible loops with fugacity α that wind around the cylinder or for an arbitrary number \\ell of defects that propagate along the full length of the cylinder. Using an enlarged periodic Temperley-Lieb algebra, we set up commuting transfer matrices acting on states whose links are considered distinct with respect to connectivity around the front or back of the cylinder. These transfer matrices satisfy a functional equation in the form of an inversion identity. For even N, this involves a non-diagonalizable braid operator J and an involution R = - (J3 - 12J)/16 = (-1)F with eigenvalues R=(-1)^{\\ell /2} . This is reminiscent of supersymmetry with a pair of defects interpreted as a fermion. The number of defects \\ell thus separates the theory into Ramond (\\ell /2 even), Neveu-Schwarz (\\ell /2 odd) and \\mathbb {Z}_4 (\\ell odd) sectors. For the case of loop fugacity α = 2, the inversion identity is solved exactly sector by sector for the eigenvalues in finite geometry. The eigenvalues are classified according to the physical combinatorics of the patterns of zeros in the complex spectral-parameter plane. This yields selection rules for the physically relevant solutions to the inversion identity. The finite-size corrections are obtained from Euler-Maclaurin formula. In the scaling limit, we obtain the conformal partition functions as sesquilinear forms and confirm the central charge c = - 2 and conformal weights \\Delta,\\bar {\\Delta }=\\Delta_t=(t^2-1)/8 . Here t=\\ell /2 and t=2r-s\\in \\mathbb {N} in the \\ell even sectors with Kac labels r = 1, 2, 3,...;s = 1, 2 while t\\in \\mathbb {Z}-\\frac 12 in the \\ell odd sectors. Strikingly, the \\ell /2 odd sectors exhibit a {\\cal W} -extended symmetry but the

  13. Measurements of the Flowfield Interaction Between Tandem Cylinders

    NASA Technical Reports Server (NTRS)

    Neuhart, Dan H.; Jenkins, Luther N.; Choudhari, Meelan M.; Khorrami, Mehdi R.

    2009-01-01

    This paper presents the most recent measurements from an ongoing investigation of the unsteady wake interference between a pair of circular cylinders in tandem. The purpose of this investigation is to help build an in-depth experimental database for this canonical flow configuration that embodies the effects of component interaction in landing gear noise. This new set of measurements augments the previous database at the primary Reynolds number (based on tunnel speed and cylinder diameter) of 1.66 105 in four important respects. First, better circumferential resolution of surface pressure fluctuations is obtained via cylinder "clocking". Second, higher resolution particle image velocimetry measurements of the shear layer separating from the cylinders are achieved. Third, the effects of simultaneous boundary layer trips along both the front and rear cylinders, versus front cylinder alone in the previous measurements, are studied. Lastly, on-surface and off-surface characteristics of unsteady flow near the "critical" cylinder spacing, wherein the flow switches intermittently between two states that are characteristic of lower and higher spacings, are examined. This critical spacing occurs in the middle of a relatively sudden change in the drag of either cylinder and is characterized by a loud intermittent noise and a flow behavior that randomly transitions between shear layer attachment to the rear cylinder and constant shedding and rollup in front of it. Analysis of this bistable flow state reveals much larger spanwise correlation lengths of surface pressure fluctuations than those at larger and smaller values of the cylinder spacing.

  14. A review of the Model 5A uranium hexafluoride cylinder

    SciTech Connect

    Dorning, R.E. II

    1989-05-23

    Both the Model 5A (Monel 400) and 5A (Monel 400) Modified five-inch cylinders have been used at the Portsmouth GDP to withdraw, store, and ship highly enriched uranium hexafluoride. As a result of a generic cracking problem with Monel 400 valve-boss material, a cylinder modification was implemented in the mid 1970s. This modification resulted in the violation of the ASME ''Code'' stamp status of the Model 5A Modified cylinder. Hydrostatic testing-to- rupture data indicated that the Model 5A Modified cylinders had ruptured strengths equivalent to that of the original Model 5A cylinders. An independent consultant reviewed the available information and confirmed that the Model 5A Modified cylinders ''will with proper maintenance continue to perform satisfactorily for many additional years of service.'' Based on the test data and consultant's review, DOE approved continued use of the 5A Modified cylinder and also requested procurement of replacement 5B cylinders be expedited. Currently, the 5A modified cylinders are in the production, storage, shipment cycle, and a sufficient number of 5B cylinders has been ordered to accommodate the projected product shipping requirements for the Navy flow. 3 tabs.

  15. CNG Cylinder Safety - Education, Outreach, and Next Steps (Presentation)

    SciTech Connect

    Smith, M.; Schroeder, A.

    2014-01-01

    Mr. Schroeder discussed the work that NREL is performing for the U.S. Department of Transportation on compressed natural gas cylinder end-of-life requirements. CNG vehicles are different from most other vehicles in that the CNG fuel storage cylinders have a pre-determined lifetime that may be shorter than the expected life of the vehicle. The end-of-life date for a cylinder is based on construction and test protocols, and is specific to the construction and material of each cylinder. The end-of-life date is important because it provides a safe margin of error against catastrophic cylinder failure or rupture. The end-of-life dates range from 15 to 25 years from the date of manufacture. NREL worked to develop outreach materials to increase awareness of cylinder end-of-life dates, has provided technical support for individual efforts related to cylinder safety and removal, and also worked with CVEF to document best practices for cylinder removal or inspection after an accident. Mr. Smith discussed the engagement of the DOE Clean Fleets Partners, which were surveyed to identify best practices on managing cylinder inventories and approached to provide initial data on cylinder age in a fleet environment. Both DOE and NREL will continue to engage these fleets and other stakeholders to determine how to best address this issue moving forward.

  16. Forced responses of solid axially polarized piezoelectric ceramic finite cylinders with internal losses.

    PubMed

    Ebenezer, D D; Ravichandran, K; Ramesh, R; Padmanabhan, Chandramouli

    2005-06-01

    A method is presented to determine the forced responses of piezoelectric cylinders using weighted sums of only certain exact solutions to the equations of motion and the Gauss electrostatic conditions. One infinite set of solutions is chosen such that each field variable is expressed in terms of Bessel functions that form a complete set in the radial direction. Another infinite set of solutions is chosen such that each field variable is expressed in terms of trigonometric functions that form a complete set in the axial direction. Another solution is used to account for the electric field that can exist even when there is no vibration. The weights are determined by using the orthogonal properties of the functions and are used to satisfy specified, arbitrary, axisymmetric boundary conditions on all the surfaces. Special cases including simultaneous mechanical and electrical excitation of cylinders are presented. All numerical results are in excellent agreement with those obtained using the finite element software ATILA. For example, the five lowest frequencies at which the conductance and susceptance of a stress-free cylinder, of length 10 mm and radius 5 mm, reach a local maximum or minimum differ by less than 0.01% from those computed using ATILA.

  17. Internal voltage in a conducting closed hollow cylinder with an attached end plate subjected to a direct lightning strike

    SciTech Connect

    Ong, M M; Anderson, R A

    2000-06-01

    The interior voltage of a large metal can with thick walls struck directly by lightning was estimated using diffusion theory, aperture slot voltage theory, and experimental data. The hollow cylinder is closed at both ends. One end has a cap that is welded to the cylinder wall making a continuous electrical interface. The other end consists of a circular plate that is pressed into the cylinder wall and held under pressure with a threaded ring. From our experience with coupling measurements, this joint will be a weak link. It will allow more current to leak into the interior than from diffusion through the walls. Because the joint was designed for mechanical purposes, the electrical properties, such as continuity around the circumference, are not well controlled. Therefore, it is difficult to determine a single voltage attributed to this joint design with varying electrical characteristics. Instead, we will make a best effort of bounding the problem using both analytical calculations and data from tests of similar structures. The calculated internal cylinder voltage subjected to an extreme lightning strike from current diffusing through the wall is 19 volts. We estimate that the press-fit end plate will increase this voltage by a factor of about two to ten. The internal voltage is expected to be between 40 and 200 volts. This uncertainty can be reduced by making coupling and high-current measurements on a number of cans or by redesigning the cap to include electrical contacts. However, given that the critical components inside the cylinder are insulated to at least 3.5 kV, improving the joint design is unnecessary. The safety factor using the worst-case maximum interior voltage is 18 and is sufficient. A higher safety margin can be achieved by keeping the joint clean and under pressure.

  18. Turbulent boundary layers along straight and curved long thin circular cylinders at low angles-of-incidence

    NASA Astrophysics Data System (ADS)

    Jordan, Stephen A.

    2016-05-01

    Long thin circular cylinders commonly serve as towed sonar tracking devices, where the radius-of-curvature along the longitudinal axis is quite low [ρr = O(10-4)]. Because no understanding presently exists about the direct impact of longitudinal curvature on the turbulent statistics, the long cylinder is simply viewed as a chain of straight segments at various (increasing then decreasing) small inclinations to the freestream direction. Realistically, even our statistical evidence along straight thin cylinders at low incidence angles is inadequate to build solid evidence towards forming reliable empirical models. In the present study, we address these shortcomings by executing Large-Eddy Simulations (LESs) of straight and longitudinally curved thin cylinders at low to moderate turbulent radius-based Reynolds numbers (500 ≤ Rea ≤ 3500) and small angles-of-incidence (α = 0° → 9°). Coupled with the previous experimental measurements and numerical results, the new expanded database (311 ≤ Rea ≤ 56 500) delivered sufficient means to propose power-law expressions for the longitudinal evolution of the skin friction, normal drag, and turbulent boundary layer (TBL) length scales. Surprisingly, the LES computations of the curved cylinders at analogous geometric and kinematic conditions as the straight cylinder showed similar character in terms of the longitudinal skin friction. Beyond incidence 1°-3° (upper end corresponds to the highest simulated Rea), the skin friction was directly proportional to the yaw angle and monotonically shifted downward with higher Rea. Conversely, the flow structure, normal drag, TBL length scales, Reynolds stresses, and the separation state of the transverse shear layers towards regular vortex shedding for the curved cylinder were highly dissimilar than the straight one at equivalent incidence angles.

  19. Magnetic neutron scattering by magnetic vortices in thin submicron-sized soft ferromagnetic cylinders

    PubMed Central

    Metlov, Konstantin L.; Michels, Andreas

    2016-01-01

    Using analytical expressions for the magnetization textures of thin submicron-sized magnetic cylinders in vortex state, we derive closed-form algebraic expressions for the ensuing small-angle neutron scattering (SANS) cross sections. Specifically, for the perpendicular and parallel scattering geometries, we have computed the cross sections for the case of small vortex-center displacements without formation of magnetic charges on the side faces of the cylinder. The results represent a significant qualitative and quantitative step forward in SANS-data analysis on isolated magnetic nanoparticle systems, which are commonly assumed to be homogeneously or stepwise-homogeneously magnetized. We suggest a way to extract the fine details of the magnetic vortex structure during the magnetization process from the SANS measurements in order to help resolving the long-standing question of the magnetic vortex displacement mode. PMID:27112640

  20. Magnetic neutron scattering by magnetic vortices in thin submicron-sized soft ferromagnetic cylinders

    NASA Astrophysics Data System (ADS)

    Metlov, Konstantin L.; Michels, Andreas

    2016-04-01

    Using analytical expressions for the magnetization textures of thin submicron-sized magnetic cylinders in vortex state, we derive closed-form algebraic expressions for the ensuing small-angle neutron scattering (SANS) cross sections. Specifically, for the perpendicular and parallel scattering geometries, we have computed the cross sections for the case of small vortex-center displacements without formation of magnetic charges on the side faces of the cylinder. The results represent a significant qualitative and quantitative step forward in SANS-data analysis on isolated magnetic nanoparticle systems, which are commonly assumed to be homogeneously or stepwise-homogeneously magnetized. We suggest a way to extract the fine details of the magnetic vortex structure during the magnetization process from the SANS measurements in order to help resolving the long-standing question of the magnetic vortex displacement mode.

  1. Generalized ``thick'' strip modelling for vortex-induced vibration of long flexible cylinders

    NASA Astrophysics Data System (ADS)

    Bao, Yan; Palocios, Rafael; Sherwin, Spencer; Nektar++ Collaboration

    2015-11-01

    We propose a generalized strip modelling method that is computationally efficient for the VIV prediction of long flexible cylinders in three-dimensional incompressible flow. In order to overcome the shortcomings of conventional strip theory-based 2D models, the fluid domain is divided into ``thick'' strips, which are sufficiently thick to locally resolve the small scale turbulence effects and three dimensionality of the flow around the cylinder. An attractive feature of the model is that we independently construct a three-dimensional scale resolving model for individual strips, which have local spanwise scale along the cylinder's axial direction and are only coupled through the structural model of the cylinder. Therefore, this model is able to cover the situations of fully resolved 3D model and 2D strip theory model. The connection between these strips is achieved through the calculation of a tensioned beam equation, which is used to represent the dynamics of the flexible body. In the limit, however, a single ``thick'' strip would request the full 3D domain. A parallel Fourier spectral/hp element method is employed to solve the 3D flow dynamics in the strip-domain, and then the VIV response prediction is achieved through the strip-structure interactions. This work is supported by EPSRC grant EP/K037536/1. Acknowledge UK Turbulence Consortium (UKTC) for ARCHER time under EPSRC grant EP/L000261/1.

  2. Generalized thick strip modelling for vortex-induced vibration of long flexible cylinders

    SciTech Connect

    Bao, Y.; Palacios, R.; Graham, M.; Sherwin, S.

    2016-09-15

    We propose a generalized strip modelling method that is computationally efficient for the VIV prediction of long flexible cylinders in three-dimensional incompressible flow. In order to overcome the shortcomings of conventional strip-theory-based 2D models, the fluid domain is divided into “thick” strips, which are sufficiently thick to locally resolve the small scale turbulence effects and three dimensionality of the flow around the cylinder. An attractive feature of the model is that we independently construct a three-dimensional scale resolving model for individual strips, which have local spanwise scale along the cylinder's axial direction and are only coupled through the structural model of the cylinder. Therefore, this approach is able to cover the full spectrum for fully resolved 3D modelling to 2D strip theory. The connection between these strips is achieved through the calculation of a tensioned beam equation, which is used to represent the dynamics of the flexible body. In the limit, however, a single “thick” strip would fill the full 3D domain. A parallel Fourier spectral/hp element method is employed to solve the 3D flow dynamics in the strip-domain, and then the VIV response prediction is achieved through the strip–structure interactions. Numerical tests on both laminar and turbulent flows as well as the comparison against the fully resolved DNS are presented to demonstrate the applicability of this approach.

  3. Numerical simulation of vibration of horizontal cylinder induced by progressive waves

    NASA Astrophysics Data System (ADS)

    Chern, Ming-Jyh; Odhiambo, E. A.; Horng, Tzyy-Leng; Borthwick, A. G. L.

    2016-02-01

    Maritime structures often comprise cylinders of small diameter relative to the prevailing wave length. This paper describes the direct forcing immersed boundary simulation of the hydroelastic behaviour of a rigid, horizontal circular cylinder in regular progressive waves. Fluid motions are numerically solved by the full Navier-Stokes equations, and the free surface by the volume-of-fluid method. The Reynolds number Re = 110, Keulegan-Carpenter number KC = 10, Froude number Fr = 0.69 and Ursell number U rs ≈ 12. A single-degree-of-freedom model is used for the elastically mounted cylinder. Velocity profiles for the stationary cylinder case have been successfully validated using experimental results. The frequency response for reduced velocities 4.5\\lt {U}R*\\lt 5.3 have been compared with theoretical data. Three transverse vibration regimes are identified: lower beating (4\\lt {U}R*\\lt 4.5); lock-in (4.7\\lt {U}R*\\lt 4.8); and upper beating (5\\lt {U}R*\\lt 10) modes. The lower and upper beating regimes exhibit varying amplitude response. The lock-in mode represents the region of fixed and maximum response. The lower beating and lock-in modes have peaks at a common vibration to wave frequency ratio {f}{{w}}* = 2. For the upper beating mode, {f}{{w}}* = 1, except for {U}R*=10 when {f}{{w}}* = 2.

  4. A methodology for combustion detection in diesel engines through in-cylinder pressure derivative signal

    NASA Astrophysics Data System (ADS)

    Luján, José M.; Bermúdez, Vicente; Guardiola, Carlos; Abbad, Ali

    2010-10-01

    In-cylinder pressure measurement has historically been used for off-line combustion diagnosis, but online application for real-time combustion control has become of great interest. This work considers low computing-cost methods for analysing the instant variation of the chamber pressure, directly obtained from the electric signal provided by a traditional piezoelectric sensor. Presented methods are based on the detection of sudden changes in the chamber pressure, which are amplified by the pressure derivative, and which are due to thermodynamic phenomena within the cylinder. Signal analysis tools both in time and in time-frequency domains are used for detecting the start of combustion, the end of combustion and the heat release peak. Results are compared with classical thermodynamic analysis and validated in several turbocharged diesel engines.

  5. A broadband polarization-independent perfect absorber with tapered cylinder structures

    NASA Astrophysics Data System (ADS)

    Wang, Jianguo; Zhu, Meiping; Sun, Jian; Yi, Kui; Shao, Jianda

    2016-12-01

    A broadband, polarization-independent, and wide angle metamaterial absorber (MA) with tapered cylinder structures is investigated with finite difference time domain simulations. The titanium nitride (TiN) and indium tin oxide (ITO) thin film are introduced as the tapered cylinder structures. The unit cell structure is mainly composed of two pairs of TiN/ITO layers and one TiN base layer. The absorption is higher than 99% between the wavelength 700 nm and 1000 nm. The broadband, polarization independent average absorption remains above 95% between 400 nm and 1200 nm with a wide range of incident angles from 0° to 40°. The electrical field intensity distributions are studied to disclose the broadband absorption mechanism. This designed broadband absorber appears to be very promising applications in the plasmonic sensing and photovoltaic devices.

  6. Reaction formulation for radiation and scattering from plates, corner reflectors and dielectric-coated cylinders

    NASA Technical Reports Server (NTRS)

    Wang, N. N.

    1974-01-01

    The reaction concept is employed to formulate an integral equation for radiation and scattering from plates, corner reflectors, and dielectric-coated conducting cylinders. The surface-current density on the conducting surface is expanded with subsectional bases. The dielectric layer is modeled with polarization currents radiating in free space. Maxwell's equation and the boundary conditions are employed to express the polarization-current distribution in terms of the surface-current density on the conducting surface. By enforcing reaction tests with an array of electric test sources, the moment method is employed to reduce the integral equation to a matrix equation. Inversion of the matrix equation yields the current distribution, and the scattered field is then obtained by integrating the current distribution. The theory, computer program and numerical results are presented for radiation and scattering from plates, corner reflectors, and dielectric-coated conducting cylinders.

  7. Ionic wind generation by a wire-cylinder-plate corona discharge in air at atmospheric pressure

    SciTech Connect

    Colas, Dorian F.; Ferret, Antoine; Pai, David Z.; Lacoste, Deanna A.; Laux, Christophe O.

    2010-11-15

    A wire-cylinder-plate electrode configuration is presented to generate ionic wind with a dc corona discharge in air at atmospheric pressure. The objective of the work is to maximize the power supplied to the flow in order to increase acceleration while avoiding breakdown. Thus, the proposed experimental setup addresses the problem of decoupling the mechanism of ion generation from that of ion acceleration. Using a wire-plate configuration as a reference, we have focused on improving the topography of the electric field to (1) separate the ionization and acceleration zones in space, and (2) guide the trajectory of charged particles as parallel to the median axis as possible. In the proposed wire-cylinder-plate setup, a dc corona discharge is generated in the space between a wire and two cylinders. The ions produced by the corona then drift past the cylinders and into a channel between two plates, where they undergo acceleration. To maximize the ionic wind it is found that the geometric configuration must be as compact as possible and that the voltage applied must be right below breakdown. Experimentally, the optimized wire-plate reference setup provides a maximum flow velocity of 8 m s{sup -1}, a flow rate per unit electrode length of 0.034 m{sup 2} s{sup -1}, and a thrust per unit electrode length of 0.24 N m{sup -1}. The wire-cylinder-plate configuration provides a maximum flow velocity of 10 m s{sup -1}, a flow rate per unit electrode length of 0.041 m{sup 2} s{sup -1}, and a thrust per unit electrode length of 0.35 N m{sup -1}. This 46% increase in thrust is obtained by increasing the electric power per unit electrode length by only 16% (from 175 to 210 W m{sup -1}), which confirms the gain in efficiency obtained with the decoupled system. In comparison with a simple wire-wire corona configuration, the wire-cylinder-plate configuration increases the ionic wind velocity by up to a factor of 3, and the thrust by an order of magnitude.

  8. Acoustics and Surface Pressure Measurements from Tandem Cylinder Configurations

    NASA Technical Reports Server (NTRS)

    Hutcheson, Florence V.; Brooks, Thomas F.; Lockard, David P.; Choudhari, Meelan M.; Stead, Daniel J.

    2014-01-01

    Acoustic and unsteady surface pressure measurements from two cylinders in tandem configurations were acquired to study the effect of spacing, surface trip and freestream velocity on the radiated noise. The Reynolds number ranged from 1.15x10(exp 5) to 2.17x10(exp 5), and the cylinder spacing varied between 1.435 and 3.7 cylinder diameters. The acoustic and surface pressure spectral characteristics associated with the different flow regimes produced by the cylinders' wake interference were identified. The dependence of the Strouhal number, peak Sound Pressure Level and spanwise coherence on cylinder spacing and flow velocity was examined. Directivity measurements were performed to determine how well the dipole assumption for the radiation of vortex shedding noise holds for the largest and smallest cylinder spacing tested.

  9. A model of filament-wound thin cylinders

    NASA Technical Reports Server (NTRS)

    Calius, Emilio P.; Springer, George S.

    1990-01-01

    A model was developed for simulating he manufacturing process of filament-wound cylinders made of a thermoset matrix composite. The model relates the process variables (winding speed, fiber tension, applied temperature) to the parameters characterizing the composite cylinder and the mandrel. The model is applicable to cylinders for which the diameter is large compared to the wall thickness. The model was implemented by a user-friendly computer code suitable for generating numerical results.

  10. Aspect ratio effect on shock-accelerated elliptic gas cylinders

    NASA Astrophysics Data System (ADS)

    Zou, Liyong; Liao, Shenfei; Liu, Cangli; Wang, Yanping; Zhai, Zhigang

    2016-03-01

    The evolution of an elliptic heavy-gas (SF6) cylinder accelerated by a planar weak shock wave is investigated experimentally using particle image velocimetry (PIV) diagnostics, and the emphasis is on the aspect ratio effect on shock-elliptic cylinder interaction. Experiments are conducted at five different aspect ratios (the ratio of length in streamwise and spanwise directions) varied from 0.25 to 4.0. PIV raw images and quantitative flow field data are obtained at t = 0.6 ms after the shock impact. As the aspect ratio increases, the interface morphology develops faster owing to more vorticity produced along the interface and smaller vortex spacing between the two vortex cores. For each case in this study, the maximal fluctuating velocity locates at the middle point of the two counter-vortices. The histograms of fluctuating velocity reveal that a distinct double-peak structure appears in the largest aspect ratio case in comparison with a single-peak structure in the smallest aspect ratio case. The vortex velocities predicted by the theoretical model [G. Rudinger and L. M. Somers, "Behaviour of small regions of different gases carried in accelerated gas flows," J. Fluid Mech. 7, 161-176 (1960)] agree well with the experimental ones. With the increase of aspect ratio, the maximal value of vorticity increases as well as the circulation, and more low-magnitude quantities are generated, which indicates the formation of multi-scale flow structure in the late mixing process. It is found that the experimental circulation of the vortex motion is reasonably estimated by the ideal point vortex-pair model.

  11. Spin-Up in a Rectangular Cylinder

    DTIC Science & Technology

    1993-12-01

    Graduate Programs in Mathematics S- QdR&r 1DTI 0TA.B 03Uxuaw:c.1ZC O d Q] Justtfieatl o DTriC QU /•ALnT I•fPECTED S ____ ,._-_ - I Distribution/ L iAvallab...I 5.7 Path of the Center of the Cyclonic Eddy ............................... 49 5.8 Distance from the Cylinder’s Comer to the Center of the Cyclonic ... cyclonic and anti- cyclonic cells whose centers are not on a 3 common horizontal axis. This result is true when the change in rotation rate, AQ, is

  12. [Fire by spontaneous combustion of oxygen cylinders].

    PubMed

    Coumans, Tanja; Maissan, Iscander M; Wolff, André P; Stolker, Robert Jan; Damen, Johan; Scheffer, Gert Jan

    2010-01-01

    The use of medicinal oxygen can be dangerous. The spontaneous combustion of an oxygen cylinder was the cause of a fire in an operating theatre and an emergency medical service. The fire developed after turning on the gas main while the flow supply valve was already open. Not opening the pressure reduction valve while the oxygen flow supply valve is open can prevent this type of fire. Information from the contractor shows that the probability of such an incident is 1 in a million.

  13. Regional stress in a noncircular cylinder.

    PubMed

    Janz, R F; Ozpetek, S; Ginzton, L E; Laks, M M

    1989-01-01

    Several mathematical formulas are presented for estimating regional average circumferential stress and shear stress in a thick-wall, noncircular cylinder with a plane of symmetry. The formulas require images of exterior and interior chamber silhouettes plus surface pressures. The formulas are primarily intended for application to the left ventricle in the short axis plane near the base (where the meridional radius of curvature is normally much larger than the circumferential radius of curvature) and to blood vessels. The formulas predict stresses in a variety of chambers to within 3% of finite element values determined from a large-scale structural analysis computer program called ANSYS.

  14. Mounting with compliant cylinders for deformable mirrors.

    PubMed

    Reinlein, Claudia; Goy, Matthias; Lange, Nicolas; Appelfelder, Michael

    2015-04-01

    A method is presented to mount large aperture unimorph deformable mirrors by compliant cylinders (CC). The CCs are manufactured from a soft silicone, and shear testing is performed in order to evaluate the Young's modulus. A scale mirror model is assembled to evaluate mount-induced change of piezoelectric deformation, and its applicability for tightly focusing mirrors. Experiments do not show any decrease of piezoelectric stroke. Further it is shown that the changes of surface fidelity by the attachment of the deformable mirror to its mount are neglectable.

  15. Coalescence of two viscous cylinders by capillarity

    SciTech Connect

    Hopper, R.W. )

    1993-12-01

    The creeping plane flow of two viscous cylinders coalescing under the influence of surface tension is described theoretically in a series of three articles. Part I is a theoretical overview. The physical assumptions affecting applicability of the theory are discussed. The shape as a function of time and of the initial diameter ratio D [>=] 1 is given in parametric form. For D = 1 and D = [infinity], the shape sequences are known exactly; for finite D > 1, a first-order differential equation is solved numerically. The time requires a quadrature. This is accurate, and easier than solving the fluid-dynamical field equations. The theory encompasses time-dependent liquid properties.

  16. Steady viscous flow past a circular cylinder

    NASA Technical Reports Server (NTRS)

    Fornberg, B.

    1984-01-01

    Viscous flow past a circular cylinder becomes unstable around Reynolds number Re = 40. With a numerical technique based on Newton's method and made possible by the use of a supercomputer, steady (but unstable) solutions have been calculated up to Re = 400. It is found that the wake continues to grow in length approximately linearly with Re. However, in conflict with available asymptotic predictions, the width starts to increase very rapidly around Re = 300. All numerical calculations have been performed on the CDC CYBER 205 at the CDC Service Center in Arden Hills, Minnesota.

  17. An update on corrosion monitoring in cylinder storage yards

    SciTech Connect

    Henson, H.M.; Newman, V.S.; Frazier, J.L.

    1991-12-31

    Depleted uranium, from US uranium isotope enrichment activities, is stored in the form of solid uranium hexafluoride (UF{sub 6}) in A285 and A516 steel cylinders designed and manufactured to ASME Boiler and Pressure Vessel Code criteria. In general, storage facilities are open areas adjacent to the enrichment plants where the cylinders are exposed to weather. This paper describes the Oak Ridge program to determine the general corrosion behavior of UF{sub 6} cylinders, to determine cylinder yard conditions which are likely to affect long term storage of this material, and to assess cylinder storage yards against these criteria. This program is targeted at conditions specific to the Oak Ridge cylinder yards. Based on (a) determination of the current cylinder yard conditions, (b) determination of rusting behavior in regions of the cylinders showing accelerated attack, (c) monitoring of corrosion rates through periodic measurement of test coupons placed within the cylinder yards, and (d) establishment of a computer base to incorporate and retain these data, the technical division is working with the enrichment sites to implement an upgraded system for storage of this material until such time as it is used or converted.

  18. An asymmetric pair of vortices adjacent to a spinning cylinder

    NASA Astrophysics Data System (ADS)

    Iosilevskii, G.; Seginer, A.

    The two-dimensional flow field over a spinning circular cylinder is analyzed using an extension of the Foeppl method. Equilibrium equations for two asymmetric point vortices in the wake of the cylinder are solved for a case when both vortices are equidistant from the cylinder. The two Foeppl solutions for the cylinder are presented. It is observed that the spin does not affect the angle between the two vortices; however, it displaces the vortex pair in the spin direction and the sinus of the displacement angle is proportional to the spin rate.

  19. Enrichment Assay Methods Development for the Integrated Cylinder Verification System

    SciTech Connect

    Smith, Leon E.; Misner, Alex C.; Hatchell, Brian K.; Curtis, Michael M.

    2009-10-22

    International Atomic Energy Agency (IAEA) inspectors currently perform periodic inspections at uranium enrichment plants to verify UF6 cylinder enrichment declarations. Measurements are typically performed with handheld high-resolution sensors on a sampling of cylinders taken to be representative of the facility's entire product-cylinder inventory. Pacific Northwest National Laboratory (PNNL) is developing a concept to automate the verification of enrichment plant cylinders to enable 100 percent product-cylinder verification and potentially, mass-balance calculations on the facility as a whole (by also measuring feed and tails cylinders). The Integrated Cylinder Verification System (ICVS) could be located at key measurement points to positively identify each cylinder, measure its mass and enrichment, store the collected data in a secure database, and maintain continuity of knowledge on measured cylinders until IAEA inspector arrival. The three main objectives of this FY09 project are summarized here and described in more detail in the report: (1) Develop a preliminary design for a prototype NDA system, (2) Refine PNNL's MCNP models of the NDA system, and (3) Procure and test key pulse-processing components. Progress against these tasks to date, and next steps, are discussed.

  20. Experimental free convection heat transfer from inclined square cylinders

    NASA Astrophysics Data System (ADS)

    Ali, Mohamed

    2016-10-01

    Natural convection from axisymmetric objects such as vertical or horizontal cylinders and spheres are two dimensional. However, for inclined circular or noncircular cylinders the flow and heat transfer is three dimensional and hence more complex and needs more attention. This study investigates the steady state mechanism of natural convection from inclined square cylinders in air. Five different cylinders of 1 m length, 8 × 8, 7 × 7, 6 × 6, 4 × 4 and 2.5 × 2.5 cm2 cross sections are used. The cylinders are heated using inserted heating element of 6 mm in diameter. Self-adhesive thermocouples are used at the upper, bottom and at one side of the cylinders for temperature measurement. Three inclination angles to the horizontal 30, 45 and 60o are used for each cylinder with uniform heat flux boundary conditions. For each cylinder, about ten heat fluxes are used to generate the heat transfer data. Local and average heat transfer coefficient is determined for each cylinder at each inclination angle for each uniform heat flux. Laminar and transition to turbulent regimes are obtained and characterized. Local critical axial distance where heat transfer coefficient changes the mode is obtained for each heat flux. Local and averaged Nusselt numbers are correlated with the modified Rayleigh numbers for all angles.