Structural optimization of the Halbach array PM rim thrust motor

NASA Astrophysics Data System (ADS)

Cao, Haichuan; Chen, Weihu

2018-05-01

The Rim-driven Thruster (RDT) integrates the thrust motor and the propeller, which can effectively reduce the space occupied by the propulsion system, improve the propulsion efficiency, and thus has important research value and broad market prospects. The Halbach Permanent Magnet Rim Thrust Motor (HPMRTM) can improve the torque density of the propulsion motor by utilizing the unilateral magnetic field of the Halbach array. In this paper, the numerical method is used to study the electromagnetic performance of the motor under different Halbach array parameters. The relationship between motor parameters such as air-gap flux density, electromagnetic torque and Halbach array parameters is obtained, and then the motor structure is optimized. By comparing with Common Permanent Magnet RTM, the advantages of HPMRTM are verified.

Development and characterization of a multi-layer magnetorheological elastomer isolator based on a Halbach array

NASA Astrophysics Data System (ADS)

Przybylski, Michal; Sun, Shuaishuai; Li, Weihua

2016-10-01

Most existing vibration isolators and dampers based on magnetorheological (MR) materials need electrical power to feed magnetic coils to stimulate the MR material, so if there is a loss of power, such as during a strong earthquake or system failure, they are unable to protect the structure. This paper outlines the design and test of a controllable multilayered magnetorheological elastomer (MRE) isolator based on a circular dipolar Halbach array; which is a set of magnets that generates a strong and uniform magnetic field. Combining an MRE layered isolator system with the Halbach array allows for constant vibration isolation with very low power consumption, where the power generated is only used to adjust the Halbach position. When this system was tested it successfully altered the lateral stiffness and damping force by 81.13% and 148.72%, respectively. This paper also includes an extended analysis of the magnetic field generated by the circular dipolar Halbach array and a discussion of the improvements that may potentially improve the range of magnetic fields generated.

Beam dynamics validation of the Halbach Technology FFAG Cell for Cornell-BNL Energy Recovery Linac

NASA Astrophysics Data System (ADS)

Méot, F.; Tsoupas, N.; Brooks, S.; Trbojevic, D.

2018-07-01

The Cornell-BNL Electron Test Accelerator (CBETA), a 150 MeV energy recovery linac (ERL) now in construction at Cornell, employs a fixed-field alternating gradient optics return loop: a single beam line comprised of FFAG cells, which accepts four recirculated energies. CBETA FFAG cell uses Halbach permanent magnet technology, its design studies have covered an extended period of time supported by extensive particle dynamics simulations using computed 3-D field map models. This approach is discussed, and illustrated here, based on the final stage in these beam dynamics studies, namely the validation of a ultimate, optimized design of the Halbach cell.

Halbach Effect at the Nanoscale from Chiral Spin Textures.

PubMed

Marioni, Miguel A; Penedo, Marcos; Baćani, Mirko; Schwenk, Johannes; Hug, Hans J

2018-04-11

Mallinson's idea that some spin textures in planar magnetic structures could produce an enhancement of the magnetic flux on one side of the plane at the expense of the other gave rise to permanent magnet configurations known as Halbach magnet arrays. Applications range from wiggler magnets in particle accelerators and free electron lasers to motors and magnetic levitation trains, but exploiting Halbach arrays in micro- or nanoscale spintronics devices requires solving the problem of fabrication and field metrology below a 100 μm size. In this work, we show that a Halbach configuration of moments can be obtained over areas as small as 1 μm × 1 μm in sputtered thin films with Néel-type domain walls of unique domain wall chirality, and we measure their stray field at a controlled probe-sample distance of 12.0 ± 0.5 nm. Because here chirality is determined by the interfacial Dyzaloshinkii-Moriya interaction, the field attenuation and amplification is an intrinsic property of this film, allowing for flexibility of design based on an appropriate definition of magnetic domains. Skyrmions (<100 nm wide) illustrate the smallest kind of such structures, for which our measurement of stray magnetic fields and mapping of the spin structure shows they funnel the field toward one specific side of the film given by the sign of the Dyzaloshinkii-Moriya interaction parameter D.

Dynamic response characteristics of high temperature superconducting maglev systems: Comparison between Halbach-type and normal permanent magnet guideways

NASA Astrophysics Data System (ADS)

Wang, B.; Zheng, J.; Che, T.; Zheng, B. T.; Si, S. S.; Deng, Z. G.

2015-12-01

The permanent magnet guideway (PMG) is very important for the performance of the high temperature superconducting (HTS) system in terms of electromagnetic force and operational stability. The dynamic response characteristics of a HTS maglev model levitating on two types of PMG, which are the normal PMG with iron flux concentration and Halbach-type PMG, were investigated by experiments. The dynamic signals for different field-cooling heights (FCHs) and loading/unloading processes were acquired and analyzed by a vibration analyzer and laser displacement sensors. The resonant frequency, stiffness and levitation height of the model were discussed. It was found that the maglev model on the Halbach-type PMG has higher resonant frequency and higher vertical stiffness compared with the normal PMG. However, the low lateral stiffness of the model on the Halbach-type PMG indicates poor lateral stability. Besides, the Halbach-type PMG has better loading capacity than the normal PMG. These results are helpful to design a suitable PMG for the HTS system in practical applications.

Magnetic superelevation design of Halbach permanent magnet guideway for high-temperature superconducting maglev

NASA Astrophysics Data System (ADS)

Lei, Wuyang; Qian, Nan; Zheng, Jun; Huang, Huan; Zhang, Ya; Deng, Zigang

2017-07-01

To improve the curve negotiating ability of high-temperature superconducting (HTS) maglev system, a special structure of magnetic superelevation for double-pole Halbach permanent magnet guideway (PMG) was designed. The most significant feature of this design is the asymmetrical PMG that forms a slanting magnetic field without affecting the smoothness of the PMG surface. When HTS maglev vehicle runs through curves with magnetic superelevation, the vehicle will slant due to asymmetry in magnetic field and the flux-pinning effect of onboard HTS bulks. At the same time, one component of the levitation force provides a part of the centripetal force that reduces lateral acceleration of the vehicle and thus enhances its curve negotiating ability. Furthermore, the slant angle of magnetic superelevation can be adjusted by changing the materials and the thickness of the added permanent magnets. This magnetic superelevation method, together with orographic uplift, can be applied to different requirements of PMG designs. Besides, the applicability of this method would benefit future development of high-speed HTS maglev system.

Halbach array type focusing actuator for small and thin optical data storage device

NASA Astrophysics Data System (ADS)

Lee, Sung Q.; Park, Kang-Ho; Paek, Mun Chul

2004-09-01

The small form factor optical data storage devices are developing rapidly nowadays. Since it is designed for portable and compatibility with flesh memory, its components such as disk, head, focusing actuator, and spindle motor should be assembled within 5 mm. The thickness of focusing actuator is within 2 mm and the total working range is +/-100um, with the resolution of less than 1μm. Since the thickness is limited tightly, it is hard to place the yoke that closes the magnetic circuit and hard to make strong flux density without yoke. Therefore, Halbach array is adopted to increase the magnetic flux of one side without yoke. The proposed Halbach array type focusing actuator has the advantage of thin actuation structure with sacrificing less flex density than conventional magnetic array. The optical head unit is moved on the swing arm type tracking actuator. Focusing coil is attached to swing arm, and Halbach magnet array is positioned at the bottom of deck along the tracking line, and focusing actuator exerts force by the Fleming's left hand rule. The dynamics, working range, control resolution of focusing actuator are analyzed and performed.

Investigation of a 7-pole/6-slot Halbach-magnetized permanent-magnet linear alternator used for free-piston stirling engines

NASA Astrophysics Data System (ADS)

Zheng, Ping; Tong, Chengde; Zhao, Jing; Yu, Bin; Li, Lin; Bai, Jingang; Zhang, Lu

2012-04-01

This paper investigates a 7-pole/6-slot Halbach-magnetized permanent-magnet linear alternator used for free piston Stirling engines (FPSEs). Taking the advantages of Halbach array, a 1 kW prototype alternator is designed. Considering the rms value of electromotive force (EMF) and harmonic distortion, the optimal length ratio of the axial- and radial-magnetized permanent magnets and thicknesses of the permanent magnets are optimized by 2D finite element method. The alternator detent force, which is an important factor for smooth operation of FPSEs, is studied by optimizing slot tip and end tooth. The load and thermal performances of the final design are simulated. A prototype alternator was designed, built and tested. Experimental data indicated satisfactory design.

Design Methodology of a Dual-Halbach Array Linear Actuator with Thermal-Electromagnetic Coupling

PubMed Central

Eckert, Paulo Roberto; Flores Filho, Aly Ferreira; Perondi, Eduardo; Ferri, Jeferson; Goltz, Evandro

2016-01-01

This paper proposes a design methodology for linear actuators, considering thermal and electromagnetic coupling with geometrical and temperature constraints, that maximizes force density and minimizes force ripple. The method allows defining an actuator for given specifications in a step-by-step way so that requirements are met and the temperature within the device is maintained under or equal to its maximum allowed for continuous operation. According to the proposed method, the electromagnetic and thermal models are built with quasi-static parametric finite element models. The methodology was successfully applied to the design of a linear cylindrical actuator with a dual quasi-Halbach array of permanent magnets and a moving-coil. The actuator can produce an axial force of 120 N and a stroke of 80 mm. The paper also presents a comparative analysis between results obtained considering only an electromagnetic model and the thermal-electromagnetic coupled model. This comparison shows that the final designs for both cases differ significantly, especially regarding its active volume and its electrical and magnetic loading. Although in this paper the methodology was employed to design a specific actuator, its structure can be used to design a wide range of linear devices if the parametric models are adjusted for each particular actuator. PMID:26978370

Design Methodology of a Dual-Halbach Array Linear Actuator with Thermal-Electromagnetic Coupling.

PubMed

Eckert, Paulo Roberto; Flores Filho, Aly Ferreira; Perondi, Eduardo; Ferri, Jeferson; Goltz, Evandro

2016-03-11

This paper proposes a design methodology for linear actuators, considering thermal and electromagnetic coupling with geometrical and temperature constraints, that maximizes force density and minimizes force ripple. The method allows defining an actuator for given specifications in a step-by-step way so that requirements are met and the temperature within the device is maintained under or equal to its maximum allowed for continuous operation. According to the proposed method, the electromagnetic and thermal models are built with quasi-static parametric finite element models. The methodology was successfully applied to the design of a linear cylindrical actuator with a dual quasi-Halbach array of permanent magnets and a moving-coil. The actuator can produce an axial force of 120 N and a stroke of 80 mm. The paper also presents a comparative analysis between results obtained considering only an electromagnetic model and the thermal-electromagnetic coupled model. This comparison shows that the final designs for both cases differ significantly, especially regarding its active volume and its electrical and magnetic loading. Although in this paper the methodology was employed to design a specific actuator, its structure can be used to design a wide range of linear devices if the parametric models are adjusted for each particular actuator.

Halbach array-based design and simulation of disc coreless permanen-magnet integrated starter generator

NASA Astrophysics Data System (ADS)

Li, Y. B.; Yang, Z. X.; Chen, W.; He, Q. Y.

2017-11-01

The functional performance, such as magnetic flux leakage, power density and efficiency, is related to the structural characteristics and design technique for the disc permanent magnet synchronous generators (PMSGs). Halbach array theory-based magnetic circuit structure is developed, and Maxwell3D simulation analysis approach of PMSG is proposed in this paper for integrated starter generator (ISG). The magnetization direction of adjacent permanent magnet is organized in difference of 45 degrees for focusing air gap side, and improving the performance of the generator. The magnetic field distribution and functional performance in load and/or unload conditions are simulated by Maxwell3D module. The proposed approach is verified by simulation analysis, the air gap flux density is 0.66T, and the phase voltage curve has the characteristics of a preferable sinusoidal wave and the voltage amplitude 335V can meet the design requirements while the disc coreless PMSG is operating at rated speed. And the developed magnetic circuit structure can be used for engineering design of the disc coreless PMSG to the integrated starter generator.

Inductional Effects in a Halbach Magnet Motion Above Distributed Inductance

NASA Astrophysics Data System (ADS)

Tchatchoua, Yves; Conrow, Ary; Kim, Dong; Morgan, Daniel; Majewski, Walerian; Zafar, Zaeema

2013-03-01

We experimented with attempts to levitate a linear (bar) Halbach array of five 1'' Nd magnets above a linear inductive track. Next, in order to achieve a control over the relative velocity, we designed a different experiment. In it a large wheel with circumferentially positioned along its rim inducting coils rotates, while the magnet is suspended directly above the rim of the wheel on a force sensor. Faraday's Law with the Lenz's Rule is responsible for the lifting and drag forces on the magnet; the horizontal drag force is measured by another force sensor. Approximating the magnet's linear relative motion over inductors with a motion along a large circle, we may use formulas derived earlier in the literature for linear inductive levitation. We measured lift and drag forces as functions of relative velocity of the Halbach magnet and the inductive ``track,'' in an approximate agreement with the existing theory. We then vary the inductance and shape of the inductive elements to find the most beneficial choice for the lift/drag ratio at the lowest relative speed.

Halbach array DC motor/generator

DOEpatents

Merritt, B.T.; Dreifuerst, G.R.; Post, R.F.

1998-01-06

A new configuration of DC motor/generator is based on a Halbach array of permanent magnets. This motor does not use ferrous materials so that the only losses are winding losses and losses due to bearings and windage. An ``inside-out`` design is used as compared to a conventional motor/generator design. The rotating portion, i.e., the rotor, is on the outside of the machine. The stationary portion, i.e., the stator, is formed by the inside of the machine. The rotor contains an array of permanent magnets that provide a uniform field. The windings of the motor are placed in or on the stator. The stator windings are then ``switched`` or ``commutated`` to provide a DC motor/generator much the same as in a conventional DC motor. The commutation can be performed by mechanical means using brushes or by electronic means using switching circuits. The invention is useful in electric vehicles and adjustable speed DC drives. 17 figs.

Halbach array DC motor/generator

DOEpatents

Merritt, Bernard T.; Dreifuerst, Gary R.; Post, Richard F.

1998-01-01

A new configuration of DC motor/generator is based on a Halbach array of permanent magnets. This motor does not use ferrous materials so that the only losses are winding losses and losses due to bearings and windage. An "inside-out" design is used as compared to a conventional motor/generator design. The rotating portion, i.e., the rotor, is on the outside of the machine. The stationary portion, i.e., the stator, is formed by the inside of the machine. The rotor contains an array of permanent magnets that provide a uniform field. The windings of the motor are placed in or on the stator. The stator windings are then "switched" or "commutated" to provide a DC motor/generator much the same as in a conventional DC motor. The commutation can be performed by mechanical means using brushes or by electronic means using switching circuits. The invention is useful in electric vehicles and adjustable speed DC drives.

Dynamics of magnetic particles in cylindrical Halbach array: implications for magnetic cell separation and drug targeting.

PubMed

Babinec, Peter; Krafcík, Andrej; Babincová, Melánia; Rosenecker, Joseph

2010-08-01

Magnetic nanoparticles for therapy and diagnosis are at the leading edge of the rapidly developing field of bionanotechnology. In this study, we have theoretically studied motion of magnetic nano- as well as micro-particles in the field of cylindrical Halbach array of permanent magnets. Magnetic flux density was modeled as magnetostatic problem by finite element method and particle motion was described using system of ordinary differential equations--Newton law. Computations were done for nanoparticles Nanomag-D with radius 65 nm, which are often used in magnetic drug targeting, as well as microparticles DynaBeads-M280 with radius 1.4 microm, which can be used for magnetic separation. Analyzing snapshots of trajectories of hundred magnetite particles of each size in the water as well as in the air, we have found that optimally designed magnetic circuits of permanent magnets in quadrupolar Halbach array have substantially shorter capture time than simple blocks of permanent magnets commonly used in experiments, therefore, such a Halbach array may be useful as a potential source of magnetic field for magnetic separation and targeting of magnetic nanoparticles as well as microparticles for delivery of drugs, genes, and cells in various biomedical applications.

A new magnetic bearing using Halbach magnet arrays for a magnetic levitation stage.

PubMed

Choi, Young-Man; Lee, Moon G; Gweon, Dae-Gab; Jeong, Jaehwa

2009-04-01

Next-generation lithography requires a high precision stage, which is compatible with a high vacuum condition. A magnetic levitation stage with six degrees-of-freedom is considered state-of-the-art technology for a high vacuum condition. The noncontact characteristic of magnetic levitation enables high precision positioning as well as no particle generation. To position the stage against gravity, z-directional electromagnetic levitation mechanisms are widely used. However, if electromagnetic actuators for levitation are used, heat is inevitably generated, which deforms the structures and degrades accuracy of the stage. Thus, a gravity compensator is required. In this paper, we propose a new magnetic bearing using Halbach magnet arrays for a magnetic levitation stage. The novel Halbach magnetic bearing exerts a force four times larger than a conventional magnetic bearing with the same volume. We also discuss the complementary characteristics of the two magnetic bearings. By modifying the height of the center magnet in a Halbach magnetic bearing, a performance compromise between levitating force density and force uniformity is obtained. The Halbach linear active magnetic bearing can be a good solution for magnetic levitation stages because of its large and uniform levitation force.

Analytical modelling of Halbach linear generator incorporating pole shifting and piece-wise spring for ocean wave energy harvesting

NASA Astrophysics Data System (ADS)

Tan, Yimin; Lin, Kejian; Zu, Jean W.

2018-05-01

Halbach permanent magnet (PM) array has attracted tremendous research attention in the development of electromagnetic generators for its unique properties. This paper has proposed a generalized analytical model for linear generators. The slotted stator pole-shifting and implementation of Halbach array have been combined for the first time. Initially, the magnetization components of the Halbach array have been determined using Fourier decomposition. Then, based on the magnetic scalar potential method, the magnetic field distribution has been derived employing specially treated boundary conditions. FEM analysis has been conducted to verify the analytical model. A slotted linear PM generator with Halbach PM has been constructed to validate the model and further improved using piece-wise springs to trigger full range reciprocating motion. A dynamic model has been developed to characterize the dynamic behavior of the slider. This analytical method provides an effective tool in development and optimization of Halbach PM generator. The experimental results indicate that piece-wise springs can be employed to improve generator performance under low excitation frequency.

Optimizing the field distribution of a Halbach type permanent magnet cylinder using the soft iron and superhard magnet

NASA Astrophysics Data System (ADS)

Xu, Xiaonong; Lu, Dingwei; Xu, Xibin; Yu, Yang; Gu, Min

2018-01-01

When a conventional Halbach type Hollow Cylindrical Permanent Magnet Array (HCPMA) is used to generate magnetic induction over the magnitude of coercivity μ0Hc, some detrimental parasitic magnetic phenomena, such as the demagnetization, magnetization reversal, and vortexes of magnetization, can appear in the interior of the magnets. We present a self-consistent quantitative analysis of the magnetization and magnetic induction distributions inside the magnetic array by considering the anisotropic and nonlinear magnetization functions of the materials consisting of the array. These numeric simulations reveal novel magnetization structures resulted from the self-field of array. We demonstrate that both the field uniformity and magnetic flux in the pole gap can be modulated by partially substituting the magnets of high energy products with the soft irons and the superhard magnets. We also show how the optimized substitution parameters can be obtained for a HCPMA achieving the best field uniformity or the maximum magnetic flux.

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…

New magnetic rails with double-layer Halbach structure by employing NdFeB and ferrite magnets for HTS maglev

NASA Astrophysics Data System (ADS)

Sun, Ruixue; Zheng, Jun; Zheng, Botian; Qian, Nan; Li, Jipeng; Deng, Zigang

2018-01-01

In the high temperature superconducting (HTS) maglev system, the magnetic rail as an essential infrastructure is needed all along the route to carry passengers and goods to the destinations. Thus, large amount of rare earth magnetic materials are required in the magnetic rail construction. In order to decrease the dependence of magnetic rails on rare earth elements, the ferrite magnet is employed to replace part of the NdFeB magnets containing rare earth elements. Consequently, a new type rail with double-layer Halbach structure is presented, which is consisted of NdFeB and ferrite magnets. In this paper, we designed and fabricated the proposed rail, and further measured its magnetic flux density distribution and electromagnetic force interacting with HTS bulks. Experimental results indicate that, this new type rail, in double-layer Halbach structure, can achieve an equivalent distribution of magnetic flux density and levitation performance as the pure NdFeB Halbach rail, while a 10% reduction in NdFeB magnet consumption can be realized at the same time. In addition this work explores another magnetic material selection for HTS maglev applications. The dependence on rare earth element and the cost of magnetic rails can be further reduced, as the coercive force of ferrite magnets improved.

A handy motion driven hybrid energy harvester: dual Halbach array based electromagnetic and triboelectric generators

NASA Astrophysics Data System (ADS)

Salauddin, M.; Park, J. Y.

2016-11-01

In this work, we have proposed and experimentally validated of hybrid electromagnetic and triboelectric energy harvester using dual Halbach magnets array excited by human handy motion. Hybrid electromagnetic (EM) and triboelectric (TE) generator that can deliver an output performance much higher than that of the individual energy-harvesting unit due to the combination operation of EM and TE mechanisms under the same mechanical movements. A Halbach array concentrates the magnetic flux lines on one side of the array while suppressing the flux lines on the other side. Dual Halbach array allows the concentrated magnetic flux lines to interact with the same coil in a way where maximum flux linkage occurs. When an external mechanical vibration is applied to the hybrid structure in the axial direction of the harvester, the suspended mass (two sided dual-Halbach-array frame) starts to oscillate within the magnetic springs and TEG part. Therefore, the TEG part, the Al film and microstructure PDMS film are collected into full contact with each other, generating triboelectric charges due to the various triboelectricities between them. A prototype of the hybrid harvester has been fabricated and tested. The EMG is capable of delivering maximum 11.5mW peak power at 32.5Ω matching load resistance and the TEG delivering 88μW peak power at 10MΩ load resistance.

Analysis and Design of Variable Stiffness Composite Cylinders

NASA Technical Reports Server (NTRS)

Tatting, Brian F.; Guerdal, Zafer

1998-01-01

laminates exists through the use of curvilinear fibers, mainly due to the presence of a weak link area within the stiffness variation that limits the ultimate load that the structure can withstand. Rigorous optimization studies reveal that even though slight increases in the critical loads can be produced for designs with an arbitrary variation of the fiber orientation angle, the improvements are not significant when compared to traditional design techniques that utilize ring stiffeners and frames. The second problem that is studied involves arbitrary loading of a cylinder with a stiffness variation that changes only in the circumferential direction. The end effects of the cylinder are ignored, so that the problem takes the form of an analysis of a cross-section for a short cylinder segment. Various load cases including axial compression, pressure, torsion, bending, and transverse shear forces are investigated. It is found that the most significant improvements in load-carrying capability exist for cases which involve loads that also vary around the circumference of the shell, namely bending and shear forces. The stiffness variation of the optimal designs contribute to the increased performance in two ways: lowering the stresses in the critical areas through redistribution of the stresses; and providing a relatively stiff region that alters the buckling behavior of the structure. These results lead to an in-depth optimization study involving weight optimization of a fuselage structure subjected to typical design constraints. Comparisons of the curvilinear fiber format to traditional stiffened structures constructed of isotropic and composite materials are included. It is found that standard variable stiffness designs are quite comparable in terms of weight and load-carrying capability yet offer the added advantage of tailorability of distinct regions of the structure that experience drastically different loading conditions. The last two problems presented in this work

Position sensor for linear synchronous motors employing halbach arrays

DOEpatents

Post, Richard Freeman

2014-12-23

A position sensor suitable for use in linear synchronous motor (LSM) drive systems employing Halbach arrays to create their magnetic fields is described. The system has several advantages over previously employed ones, especially in its simplicity and its freedom from being affected by weather conditions, accumulated dirt, or electrical interference from the LSM system itself.

Halbach array generator/motor having an automatically regulated output voltage and mechanical power output

DOEpatents

Post, Richard F.

2005-02-22

A motor/generator having its stationary portion, i.e., the stator, positioned concentrically within its rotatable element, i.e., the rotor, along its axis of rotation. The rotor includes a Halbach array. The stator windings are switched or commutated to provide a DC motor/generator much the same as in a conventional DC motor/generator. The voltage and power are automatically regulated by using centrifugal force to change the diameter of the rotor, and thereby vary the radial gap in between the stator and the rotating Halbach array, as a function of the angular velocity of the rotor.

Error studies of Halbach Magnets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brooks, S.

2017-03-02

These error studies were done on the Halbach magnets for the CBETA “First Girder” as described in note [CBETA001]. The CBETA magnets have since changed slightly to the lattice in [CBETA009]. However, this is not a large enough change to significantly affect the results here. The QF and BD arc FFAG magnets are considered. For each assumed set of error distributions and each ideal magnet, 100 random magnets with errors are generated. These are then run through an automated version of the iron wire multipole cancellation algorithm. The maximum wire diameter allowed is 0.063” as in the proof-of-principle magnets. Initially,more » 32 wires (2 per Halbach wedge) are tried, then if this does not achieve 1e-­4 level accuracy in the simulation, 48 and then 64 wires. By “1e-4 accuracy”, it is meant the FOM defined by √(Σ n≥sextupole a n 2+b n 2) is less than 1 unit, where the multipoles are taken at the maximum nominal beam radius, R=23mm for these magnets. The algorithm initially uses 20 convergence interations. If 64 wires does not achieve 1e-­4 accuracy, this is increased to 50 iterations to check for slow converging cases. There are also classifications for magnets that do not achieve 1e-4 but do achieve 1e-3 (FOM ≤ 10 units). This is technically within the spec discussed in the Jan 30, 2017 review; however, there will be errors in practical shimming not dealt with in the simulation, so it is preferable to do much better than the spec in the simulation.« less

Optical cylinder designs to increase the field of vision in the osteo-odonto-keratoprosthesis.

PubMed

Hull, C C; Liu, C S; Sciscio, A; Eleftheriadis, H; Herold, J

2000-12-01

The single optical cylinders used in the osteo-odonto-keratoprosthesis (OOKP) are known to produce very small visual fields. Values of 40 degrees are typically quoted. The purpose of this paper is to present designs for new optical cylinders that significantly increase the field of view and therefore improve the visual rehabilitation of patients having an OOKP. Computer ray-tracing techniques were used to design and analyse improved one- and two-piece optical cylinders made from polymethyl methacrylate. All designs were required to have a potential visual acuity of 6/6 before consideration was given to the visual field and optimising off-axis image quality. Aspheric surfaces were used where this significantly improved off-axis image quality. Single optical cylinders, with increased posterior cylinder (intraocular) diameters, gave an increase in the theoretical visual field of 18% (from 76 degrees to 90 degrees) over current designs. Two-piece designs based on an inverted telephoto principle gave theoretical field angles over 120 degrees. Aspheric surfaces were shown to improve the off-axis image quality while maintaining a potential visual acuity of at least 6/6. This may well increase the measured visual field by improving the retinal illuminance off-axis. Results demonstrate that it is possible to significantly increase the theoretical maximum visual field through OOKP optical cylinders. Such designs will improve the visual rehabilitation of patients undergoing this procedure.

Optimal Design of General Stiffened Composite Circular Cylinders for Global Buckling with Strength Constraints

NASA Technical Reports Server (NTRS)

Jaunky, N.; Ambur, D. R.; Knight, N. F., Jr.

1998-01-01

A design strategy for optimal design of composite grid-stiffened cylinders subjected to global and local buckling constraints and strength constraints was developed using a discrete optimizer based on a genetic algorithm. An improved smeared stiffener theory was used for the global analysis. Local buckling of skin segments were assessed using a Rayleigh-Ritz method that accounts for material anisotropy. The local buckling of stiffener segments were also assessed. Constraints on the axial membrane strain in the skin and stiffener segments were imposed to include strength criteria in the grid-stiffened cylinder design. Design variables used in this study were the axial and transverse stiffener spacings, stiffener height and thickness, skin laminate stacking sequence and stiffening configuration, where stiffening configuration is a design variable that indicates the combination of axial, transverse and diagonal stiffener in the grid-stiffened cylinder. The design optimization process was adapted to identify the best suited stiffening configurations and stiffener spacings for grid-stiffened composite cylinder with the length and radius of the cylinder, the design in-plane loads and material properties as inputs. The effect of having axial membrane strain constraints in the skin and stiffener segments in the optimization process is also studied for selected stiffening configurations.

Optimal Design of General Stiffened Composite Circular Cylinders for Global Buckling with Strength Constraints

NASA Technical Reports Server (NTRS)

Jaunky, Navin; Knight, Norman F., Jr.; Ambur, Damodar R.

1998-01-01

A design strategy for optimal design of composite grid-stiffened cylinders subjected to global and local buckling constraints and, strength constraints is developed using a discrete optimizer based on a genetic algorithm. An improved smeared stiffener theory is used for the global analysis. Local buckling of skin segments are assessed using a Rayleigh-Ritz method that accounts for material anisotropy. The local buckling of stiffener segments are also assessed. Constraints on the axial membrane strain in the skin and stiffener segments are imposed to include strength criteria in the grid-stiffened cylinder design. Design variables used in this study are the axial and transverse stiffener spacings, stiffener height and thickness, skin laminate stacking sequence, and stiffening configuration, where herein stiffening configuration is a design variable that indicates the combination of axial, transverse, and diagonal stiffener in the grid-stiffened cylinder. The design optimization process is adapted to identify the best suited stiffening configurations and stiffener spacings for grid-stiffened composite cylinder with the length and radius of the cylinder, the design in-plane loads, and material properties as inputs. The effect of having axial membrane strain constraints in the skin and stiffener segments in the optimization process is also studied for selected stiffening configuration.

A novel type of rim thrust motor with Halbach array permanent magnet rotor

NASA Astrophysics Data System (ADS)

Cao, Haichuan; Chen, Weihu

2018-05-01

The Rim-driven Thruster (RDT) is a new type of marine electric thruster proposed in recent years. In this paper, the author proposed a new type of permanent magnet synchronous rim thrust motor (RTM). The motor uses a Halbach array permanent magnet rotor, which can improve the torque density of the propulsion motor by utilizing the unilateral magnetic field of the Halbach array. In this paper, the electromagnetic properties of the motor were measured and compared with that of the ordinary magnetic pole motor through numerical analysis. The results show that at the same power, the new motor can significantly reduce the thickness of the rotor's permanent magnet and yoke core, and has obvious advantages in power density, moment of inertia, dynamic performance, and cost.

Analytical torque calculation and experimental verification of synchronous permanent magnet couplings with Halbach arrays

NASA Astrophysics Data System (ADS)

Seo, Sung-Won; Kim, Young-Hyun; Lee, Jung-Ho; Choi, Jang-Young

2018-05-01

This paper presents analytical torque calculation and experimental verification of synchronous permanent magnet couplings (SPMCs) with Halbach arrays. A Halbach array is composed of various numbers of segments per pole; we calculate and compare the magnetic torques for 2, 3, and 4 segments. Firstly, based on the magnetic vector potential, and using a 2D polar coordinate system, we obtain analytical solutions for the magnetic field. Next, through a series of processes, we perform magnetic torque calculations using the derived solutions and a Maxwell stress tensor. Finally, the analytical results are verified by comparison with the results of 2D and 3D finite element analysis and the results of an experiment.

Beam dynamics validation of the Halbach Technology FFAG Cell for Cornell-BNL Energy Recovery Linac

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meot, Francois; Tsoupas, N.; Brooks, S.

The Cornell-BNL Electron Test Accelerator (CBETA), a 150 MeV energy recovery linac (ERL) now in construction at Cornell, employs a fixed-field alternating gradient optics return loop: a single beam line comprised of FFAG cells, which accepts four recirculated energies. CBETA FFAG cell uses Halbach permanent magnet technology, its design studies have covered an extended period of time supported by extensive particle dynamics simulations using computed 3-D field map models. As a result, this approach is discussed, and illustrated here, based on the final stage in these beam dynamics studies, namely the validation of a ultimate, optimized design of the Halbachmore » cell.« less

Beam dynamics validation of the Halbach Technology FFAG Cell for Cornell-BNL Energy Recovery Linac

DOE PAGES

Meot, Francois; Tsoupas, N.; Brooks, S.; ...

2018-04-16

The Cornell-BNL Electron Test Accelerator (CBETA), a 150 MeV energy recovery linac (ERL) now in construction at Cornell, employs a fixed-field alternating gradient optics return loop: a single beam line comprised of FFAG cells, which accepts four recirculated energies. CBETA FFAG cell uses Halbach permanent magnet technology, its design studies have covered an extended period of time supported by extensive particle dynamics simulations using computed 3-D field map models. As a result, this approach is discussed, and illustrated here, based on the final stage in these beam dynamics studies, namely the validation of a ultimate, optimized design of the Halbachmore » cell.« less

A tubular hybrid Halbach/axially-magnetized permanent-magnet linear machine

NASA Astrophysics Data System (ADS)

Sui, Yi; Liu, Yong; Cheng, Luming; Liu, Jiaqi; Zheng, Ping

2017-05-01

A single-phase tubular permanent-magnet linear machine (PMLM) with hybrid Halbach/axially-magnetized PM arrays is proposed for free-piston Stirling power generation system. Machine topology and operating principle are elaborately illustrated. With the sinusoidal speed characteristic of the free-piston Stirling engine considered, the proposed machine is designed and calculated by finite-element analysis (FEA). The main structural parameters, such as outer radius of the mover, radial length of both the axially-magnetized PMs and ferromagnetic poles, axial length of both the middle and end radially-magnetized PMs, etc., are optimized to improve both the force capability and power density. Compared with the conventional PMLMs, the proposed machine features high mass and volume power density, and has the advantages of simple control and low converter cost. The proposed machine topology is applicable to tubular PMLMs with any phases.

Optimizing Power Density and Efficiency of a Double-Halbach Array Permanent-Magnet Ironless Axial-Flux Motor

NASA Technical Reports Server (NTRS)

Duffy, Kirsten P.

2016-01-01

NASA Glenn Research Center is investigating hybrid electric and turboelectric propulsion concepts for future aircraft to reduce fuel burn, emissions, and noise. Systems studies show that the weight and efficiency of the electric system components need to be improved for this concept to be feasible. This effort aims to identify design parameters that affect power density and efficiency for a double-Halbach array permanent-magnet ironless axial flux motor configuration. These parameters include both geometrical and higher-order parameters, including pole count, rotor speed, current density, and geometries of the magnets, windings, and air gap.

Design and CFD analysis of intake port and exhaust port for a 4 valve cylinder head engine

NASA Astrophysics Data System (ADS)

Latheesh, V. M.; Parthasarathy, P.; Baskaran, V.; Karthikeyan, S.

2018-02-01

In cylinder air motion in a compression ignition engine effects mixing of air-fuel, quality of combustion and emission produced. The primary objective is to design and analyze intake and the exhaust port for a four valve cylinder head to meet higher emission norms for a given diesel engine with two valves. In this work, an existing cylinder head designed for two valves was redesigned with 4 valves. The modern trend also confirms this approach. This is being followed in the design and development of new generation engines to meet the stringent environment norms, competition in market and demand for more fuel-efficient engines. The swirl ratio and flow coefficient were measured for different valve lifts using STAR CCM+. CFD results were validated with the two-valve cylinder experimental results. After validation, a comparison between two-valve and four-valve cylinder head was done. The conversion of two valve cylinder head to 4 valves may not support modern high swirl generating port layout and requires a trade-off between many design parameters.

Test Method Designed to Evaluate Cylinder Liner-Piston Ring Coatings for Advanced Heat Engines

NASA Technical Reports Server (NTRS)

Radil, Kevin C.

1997-01-01

Research on advanced heat engine concepts, such as the low-heat-rejection engine, have shown the potential for increased thermal efficiency, reduced emissions, lighter weight, simpler design, and longer life in comparison to current diesel engine designs. A major obstacle in the development of a functional advanced heat engine is overcoming the problems caused by the high combustion temperatures at the piston ring/cylinder liner interface, specifically at top ring reversal (TRR). Therefore, advanced cylinder liner and piston ring materials are needed that can survive under these extreme conditions. To address this need, researchers at the NASA Lewis Research Center have designed a tribological test method to help evaluate candidate piston ring and cylinder liner materials for advanced diesel engines.

Reliability Analysis and Reliability-Based Design Optimization of Circular Composite Cylinders Under Axial Compression

NASA Technical Reports Server (NTRS)

Rais-Rohani, Masoud

2001-01-01

This report describes the preliminary results of an investigation on component reliability analysis and reliability-based design optimization of thin-walled circular composite cylinders with average diameter and average length of 15 inches. Structural reliability is based on axial buckling strength of the cylinder. Both Monte Carlo simulation and First Order Reliability Method are considered for reliability analysis with the latter incorporated into the reliability-based structural optimization problem. To improve the efficiency of reliability sensitivity analysis and design optimization solution, the buckling strength of the cylinder is estimated using a second-order response surface model. The sensitivity of the reliability index with respect to the mean and standard deviation of each random variable is calculated and compared. The reliability index is found to be extremely sensitive to the applied load and elastic modulus of the material in the fiber direction. The cylinder diameter was found to have the third highest impact on the reliability index. Also the uncertainty in the applied load, captured by examining different values for its coefficient of variation, is found to have a large influence on cylinder reliability. The optimization problem for minimum weight is solved subject to a design constraint on element reliability index. The methodology, solution procedure and optimization results are included in this report.

Design of on line detection system for static evaporation rate of LNG vehicle cylinders

NASA Astrophysics Data System (ADS)

Tang, P.; Wang, M.; Tan, W. H.; Ling, Z. W.; Li, F.

2017-06-01

In order to solve the problems existing in the regular inspection of LNG vehicle cylinders, the static evaporation rate on line detection system of LNG cylinders is discussed in this paper. A non-disassembling, short-term and high-efficiency on line detection system for LNG vehicle cylinders is proposed, which can meet the requirement of evaporation rate test under different media and different test pressures. And then test methods under the experimental conditions, atmospheric pressure and pressure are given respectively. This online detection system designed in this paper can effectively solve the technical problems during the inspection of the cylinder.

Design of Feedforward Controller to Reduce Force Ripple for Linear Motor using Halbach Magnet Array with T Shape Magnet

NASA Astrophysics Data System (ADS)

Kim, Moojong; Kim, Jinyoung; Lee, Moon G.

Recently, in micro/nano fabrication equipments, linear motors are widely used as an actuator to position workpiece, machining tool and measurement head. To control them faster and more precise, the motor should have high actuating force and small force ripple. High actuating force enable us to more workpiece with high acceleration. Eventually, it may provide higher throughput. Force ripple gives detrimental effect on the precision and tracking performance of the equipments. In order to accomplish more precise motion, it is important to make lower the force ripple. Force ripple is categorized into cogging and mutual ripple. First is dependent on the shape of magnets and/or core. The second is not dependent on them but dependent on current commutation. In this work, coreless mover i.e. coil winding is applied to the linear motor to avoid the cogging ripple. Therefore, the mutual ripple is only considered to be minimized. Ideal Halbach magnet array has continuously varying magnetization. The THMA (Halbach magnet array with T shape magnets) is proposed to approximate the ideal one. The THMA can not produce ideal sinusoidal flux, therefore, the linear motor with THMA and sinusoidal commutation of current generates the mutual force ripple. In this paper, in order to compensate mutual force ripple by feedforward(FF) controller, we calculate the optimized commutation of input current. The ripple is lower than 1.17% of actuating force if the commutation current agree with the magnetic flux from THMA. The performance of feedforward(FF) controller is verified by experiment.

A portable Halbach magnet that can be opened and closed without force: The NMR-CUFF

NASA Astrophysics Data System (ADS)

Windt, Carel W.; Soltner, Helmut; Dusschoten, Dagmar van; Blümler, Peter

2011-01-01

Portable equipment for nuclear magnetic resonance (NMR) is becoming increasingly attractive for use in a variety of applications. One of the main scientific challenges in making NMR portable is the design of light-weight magnets that possess a strong and homogeneous field. Existing NMR magnets can provide such magnetic fields, but only for small samples or in small regions, or are rather heavy. Here we show a simple yet elegant concept for a Halbach-type permanent magnet ring, which can be opened and closed with minimal mechanical force. An analytical solution for an ideal Halbach magnet shows that the magnetic forces cancel if the structure is opened at an angle of 35.3° relative to its poles. A first prototype weighed only 3.1 kg, and provided a flux density of 0.57 T with a homogeneity better than 200 ppm over a spherical volume of 5 mm in diameter without shimming. The force needed to close it was found to be about 20 N. As a demonstration, intact plants were imaged and water (xylem) flow measured. Magnets of this type (NMR-CUFF = Cut-open, Uniform, Force Free) are ideal for portable use and are eminently suited to investigate small or slender objects that are part of a larger or immobile whole, such as branches on a tree, growing fruit on a plant, or non-metallic tubing in industrial installations. This new concept in permanent-magnet design enables the construction of openable, yet strong and homogeneous magnets, which aside from use in NMR or MRI could also be of interest for applications in accelerators, motors, or magnetic bearings.

Design and fabrication of a high-precision cylinder beam expander

NASA Astrophysics Data System (ADS)

Zhang, Yong-hong; Yan, Hong; Xie, Bing; Li, Jian-ming; Luo, Zhong-xiang

2018-03-01

In order to compress the beam divergence angle and reduce the energy density, beam expansion system is widely used to expand the beam in laser system. Cylinder beam expander belongs to one-dimension expander, which expands the laser beam in only one direction (X direction or Y direction), a refraction cylinder expander whose beam diameter is 180mm×120mm and magnitude ratio is 12 is designed in this paper, the working wavelength is 1058nm. To solve the problem of inequality of the working wavelength and the testing wavelength, compensation method of using parallel plate to test the system aberration is proposed. By rough grinding (precision grinding) polish and the system grinding, the final system aberration is 0.24λ(peak-valley value)

Topology optimization for design of segmented permanent magnet arrays with ferromagnetic materials

NASA Astrophysics Data System (ADS)

Lee, Jaewook; Yoon, Minho; Nomura, Tsuyoshi; Dede, Ercan M.

2018-03-01

This paper presents multi-material topology optimization for the co-design of permanent magnet segments and iron material. Specifically, a co-design methodology is proposed to find an optimal border of permanent magnet segments, a pattern of magnetization directions, and an iron shape. A material interpolation scheme is proposed for material property representation among air, permanent magnet, and iron materials. In this scheme, the permanent magnet strength and permeability are controlled by density design variables, and permanent magnet magnetization directions are controlled by angle design variables. In addition, a scheme to penalize intermediate magnetization direction is proposed to achieve segmented permanent magnet arrays with discrete magnetization directions. In this scheme, permanent magnet strength is controlled depending on magnetization direction, and consequently the final permanent magnet design converges into permanent magnet segments having target discrete directions. To validate the effectiveness of the proposed approach, three design examples are provided. The examples include the design of a dipole Halbach cylinder, magnetic system with arbitrarily-shaped cavity, and multi-objective problem resembling a magnetic refrigeration device.

Anti-buckling design of variable stiffness composite cylinder under combined loading based on the multi-objective optimization method

NASA Astrophysics Data System (ADS)

Zheng, Y.; Chen, J.

2018-06-01

Variable stiffness composite structures take full advantages of composite’s design ability. An enlarged design space will make the structure’s performance more excellent. Through an optimal design of a variable stiffness cylinder, the buckling capacity of the cylinder will be increased as compared with its constant stiffness counterpart. In this paper, variable stiffness composite cylinders sustaining combined loadings are considered, and the optimization is conducted based on the multi-objective optimization method. The results indicate that variable stiffness cylinder’s loading capacity is increased significantly as compared with the constant stiffness, especially when an inhomogeneous loading is considered.

Structure reliability design and analysis of support ring for cylinder seal

NASA Astrophysics Data System (ADS)

Minmin, Zhao

2017-09-01

In this paper, the general reliability design process of the cross-sectional dimension of the support ring is introduced, which is used for the cylinder sealing. Then, taking a certain section shape support ring as an example, the every size parameters of section are determined from the view point of reliability design. Last, the static strength and reliability of the support ring are analyzed to verify the correctness of the reliability design result.

Design of the liquefied natural gas (LNG) vehicle gas cylinder filling semi-physical simulation training and assessment system

NASA Astrophysics Data System (ADS)

Gao, Jie; Zheng, Jianrong; Zhao, Yinghui

2017-08-01

With the rapid development of LNG vehicle in China, the operator's training and assessment of the operating skills cannot operate on material objects, because of Vehicle Gas Cylinder's high pressure, flammable and explosive characteristics. LNG Vehicle Gas Cylinder's filling simulation system with semi-physical simulation technology presents the overall design and procedures of the simulation system, and elaborates the realization of the practical analog machine, data acquisition and control system and the computer software, and introduces the design process of equipment simulation model in detail. According to the designed assessment system of the Vehicle Gas Cylinder, it can obtain the operation on the actual cylinder filling and visual effects for the operator, and automatically record operation, the results of real operation with its software, and achieve the operators' training and assessment of operating skills on mobile special equipment.

Three-Dimensional Field Solutions for Multi-Pole Cylindrical Halbach Arrays in an Axial Orientation

NASA Technical Reports Server (NTRS)

Thompson, William K.

2006-01-01

This article presents three-dimensional B field solutions for the cylindrical Halbach array in an axial orientation. This arrangement has applications in the design of axial motors and passive axial magnetic bearings and couplers. The analytical model described here assumes ideal magnets with fixed and uniform magnetization. The field component functions are expressed as sums of 2-D definite integrals that are easily computed by a number of mathematical analysis software packages. The analysis is verified with sample calculations and the results are compared to equivalent results from traditional finite-element analysis (FEA). The field solutions are then approximated for use in flux linkage and induced EMF calculations in nearby stator windings by expressing the field variance with angular displacement as pure sinusoidal function whose amplitude depends on radial and axial position. The primary advantage of numerical implementation of the analytical approach presented in the article is that it lends itself more readily to parametric analysis and design tradeoffs than traditional FEA models.

Geometric design and mechanical behavior of a deployable cylinder with Miura origami

NASA Astrophysics Data System (ADS)

Cai, Jianguo; Deng, Xiaowei; Feng, Jian; Zhou, Ya

2015-12-01

The folding and deployment of a cylinder with Miura origami patterns are studied in this paper. First, the geometric formulation of the design problem is discussed. Then the loading case of the axial strains and corresponding external nodal loads applied on the vertices of the top polygon during the motion is investigated analytically. The influence of the angle between the diagonal and horizontal fold lines α and β and the number of Miura origami elements n on the dynamic behavior of the basic segment is also discussed. Then the dynamic behavior is analyzed using numerical simulations. Finally, the deployment process of a cylinder with multi-stories is discussed. The numerical results agree well with the analytical predictions. The results show that the range of motion, i.e. the maximal displacement of top nodes, will also increase with the increase of angles α and β. This cylinder, with a smaller n, may have a bistable behavior. When n is larger, the influence of n on the axial strains and external nodal loads is slight. The numerical results agree well with the analytical predictions. Moreover, the deployment of the cylinder with multi-stories is non-uniform, which deploys from the upper story to the lower story.

Fracture mechanics analysis of NGV fuel cylinders. Part 1: Steel cylinders

NASA Astrophysics Data System (ADS)

Connolly, M. P.; Hudak, S. J.; Roy, S.

1993-02-01

Compressed natural gas (CNG) cylinders for natural gas vehicles (NGVs) are subject to a combination of pressure cycles, associated with periodic refueling, and a potentially corrosive CNG environment. Under these conditions it has been shown that the life of the cylinder is governed by the corrosion-fatigue crack growth of internal flaws such as voids, pits or folds that may be present after manufacture. For NGV applications, these cylinders are required to operate for at least 15 years and the report, through a detailed fracture mechanics analysis, describes approaches to achieving the desired life. The analysis shows that a 15 year cylinder life can be obtained by using quality control to ensure that no initial defects greater than 0.045 in. X 0.090 in. exist after manufacture. Alternatively, gas drying can be used at the distribution stations to reduce the detrimental effects of the remaining CNG impurities, and thereby, produce long cylinder lives. The analysis also considers the role of in-service inspection/retest and shows that in-service NDE has little advantage, either technically or economically, for ensuring the fitness-for-service of steel NGV cylinders. The analysis also shows that hydrostatic testing of cylinders, either at manufacture or in service, is ineffective for detecting fatigue cracks and therefore should not be implemented as part of a fitness-for-service plan for NGV fuel cylinders. The issue of cylinder geometry was also considered and the analysis shows that improperly designed flat-bottomed CNG cylinders can result in premature fatigue failures originating at the inner wall in the transition region between the cylinder end and sidewall.

A novel multiport cylinder dryer.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, S. U.; Yu, W.; France, D. M.

2001-02-01

A multiport dryer design concept that could create breakthroughs in the drying of pulp and paper is under development. The feasibility of this novel concept was demonstrated in a proof-of-concept test. Experiments were performed in a specially designed test apparatus to investigate the condensing heat-transfer characteristics of a single channel (representative of a multiport cylinder dryer) under typical operating conditions. The experimental results showed that multiport cylinder-dryer technology provides very high heat-transfer coefficients of 15,000 W/m{sup 2}{center_dot}K (2600 Btu/h{center_dot}ft{sup 2} {sup o}F) and a highly uniform distribution of cylinder-wall temperature. These experimental results suggest that a multiport cylinder dryer canmore » increase the rate of paper drying compared with a conventional cylinder dryer. The increased dryer efficiency translates into either a reduction in the number of dryers at the same level of production or an increase in the rate of production with the same number of dryers.« less

Effects of Buckling Knockdown Factor, Internal Pressure and Material on the Design of Stiffened Cylinders

NASA Technical Reports Server (NTRS)

Lovejoy, Andrew E.; Hilburger, Mark W.; Chunchu, Prasad B.

2010-01-01

A design study was conducted to investigate the effect shell buckling knockdown factor (SBKF), internal pressure and aluminum alloy material selection on the structural weight of stiffened cylindrical shells. Two structural optimization codes were used for the design study to determine the optimum minimum-weight design for a series of design cases, and included an in-house developed genetic algorithm (GA) code and PANDA2. Each design case specified a unique set of geometry, material, knockdown factor combinations and loads. The resulting designs were examined and compared to determine the effects of SBKF, internal pressure and material selection on the acreage design weight and controlling failure mode. This design study shows that use of less conservative SBKF values, including internal pressure, and proper selection of material alloy can result in significant weight savings for stiffened cylinders. In particular, buckling-critical cylinders with integrally machined stiffener construction can benefit from the use of thicker plate material that enables taller stiffeners, even when the stiffness, strength and density properties of these materials appear to be inferior.

Laminated track design for inductrack maglev systems

DOEpatents

Post, Richard F.

2004-07-06

A magnet configuration comprising a pair of Halbach arrays magnetically and structurally connected together are positioned with respect to each other so that a first component of their fields substantially cancels at a first plane between them, and a second component of their fields substantially adds at this first plane. A track is located between the pair of Halbach arrays and a propulsion mechanism is provided for moving the pair of Halbach arrays along the track. When the pair of Halbach arrays move along the track and the track is not located at the first plane, a current is induced in the windings and a restoring force is exerted on the pair of Halbach arrays.

Topology optimization of reduced rare-earth permanent magnet arrays with finite coercivity

NASA Astrophysics Data System (ADS)

Teyber, R.; Trevizoli, P. V.; Christiaanse, T. V.; Govindappa, P.; Rowe, A.

2018-05-01

The supply chain risk of rare-earth permanent magnets has yielded research efforts to improve both materials and magnetic circuits. While a number of magnet optimization techniques exist, literature has not incorporated the permanent magnet failure process stemming from finite coercivity. To address this, a mixed-integer topology optimization is formulated to maximize the flux density of a segmented Halbach cylinder while avoiding permanent demagnetization. The numerical framework is used to assess the efficacy of low-cost (rare-earth-free ferrite C9), medium-cost (rare-earth-free MnBi), and higher-cost (Dy-free NdFeB) permanent magnet materials. Novel magnet designs are generated that produce flux densities 70% greater than the segmented Halbach array, albeit with increased magnet mass. Three optimization formulations are then explored using ferrite C9 that demonstrates the trade-off between manufacturability and design sophistication, generating flux densities in the range of 0.366-0.483 T.

Lower bound buckling loads for design of laminate composite cylinders

NASA Astrophysics Data System (ADS)

Croll, James G. A.; Wang, Hongtao

2017-01-01

Over a period of more than 45 years, an extensive research program has allowed a series of very simple propositions, relating to the safe design of shells experiencing imperfection sensitive buckling, to be recast in the form of a series of lemmas. These are briefly summarized and their practical use is illustrated in relation to the prediction of safe lower bounds to the imperfection sensitive buckling of axially loaded, fiber reinforced polymeric, laminated cylinders. With a fundamental aspect of the approach, sometimes referred to as the reduced stiffness method, being the delineation of the various shell membrane and bending stiffness (or perhaps more appropriately energy) components contributing to the buckling resistance, the method will be shown to also provide a powerful way of making rational design decisions to optimize the use of fiber reinforcement.

Finite element analysis of cylinder shell resonator and design of intelligent density meter

NASA Astrophysics Data System (ADS)

W, Sui X.; M, Fan Y.; X, Zhang G.; R, Qiu Z.

2005-01-01

On the basis of the mathematical model and finite element analysis of the cylinder shell resonator, a novel resonant liquid density meter is designed. The meter consists of a cylinder shell resonator fixed on both ends, a measurement circuit with automatic gain control and automatic phase control, and a signal processing system with microcomputer unit C8051F021. The density meter is insensitive to the liquid pressure, and it can intelligently compensate for the temperature. The experiment results show the meter characteristic coefficients of K0, K1, and K2 at 25 centigrade are -129.5668 kg m-3, -0.2535 × 106 kg m-3 s-1 and 0.6239 × 1010 kg m-3 s-2, respectively. The accuracy of the sensor is ±0.1% in range of 700-900 kg m-3

Simple Formulas and Results for Buckling-Resistance and Stiffness Design of Compression-Loaded Laminated-Composite Cylinders

NASA Technical Reports Server (NTRS)

Nemeth, Michael P.; Mikulas, Martin M., Jr.

2009-01-01

Simple formulas for the buckling stress of homogeneous, specially orthotropic, laminated-composite cylinders are presented. The formulas are obtained by using nondimensional parameters and equations that facilitate general validation, and are validated against the exact solution for a wide range of cylinder geometries and laminate constructions. Results are presented that establish the ranges of the nondimensional parameters and coefficients used. General results, given in terms of the nondimensional parameters, are presented that encompass a wide range of geometries and laminate constructions. These general results also illustrate a wide spectrum of behavioral trends. Design-oriented results are also presented that provide a simple, clear indication of laminate composition on critical stress, critical strain, and axial stiffness. An example is provided to demonstrate the application of these results to thin-walled column designs.

[Design and experiment of a needle-to-cylinder electrode structure realizing the negative DC glow discharge in ambient air].

PubMed

Li, Hua; Wei, Chang-Yan; Liu, Chun-Xia; Shen, Xian-Hao; Chen, Zhen-Cheng

2014-07-01

A new needle-to-cylinder electrode structure was designed to realize the stable glow discharge in ambient air. The stainless steel needle tip with diameter 56.4 microm and the copper cylinder with diameter 4mm were chosen as the cathode and the anode respectively, which were kept parallel by accurate mechanical structure. In the condition that the distance between the needle and the cylinder is 2 mm, the ballasting resistor is 10 M(omega), the discharge resistor is 10 M(omega), the testing resistor is 1 k(omega), and the discharge voltage is -2 740 V, without air flow in ambient air and at room temperature, the stable glow discharge between the needle and the cylinder was realized. Three different discharge modes can be observed: corona discharge, glow discharge and spark, which were verified by the discharge waveform stored in the oscilloscope, and the discharge pictures were recorded by digital camera. The needle-to-cylinder electrode structure is easy to fabricate by the MEMS technology, which can be used as the ion source of the portable analyzing instruments.

PIV measurements of airflow past multiple cylinders

NASA Astrophysics Data System (ADS)

Wodziak, Waldemar; Sobczyk, Jacek

2018-06-01

Flow characteristics in vicinity of six circular cylinders aligned inline was investigated experimentally by means of PIV method. Experiments were conducted in a low speed closed circuit wind tunnel. Inflow velocity was 1.2 m/s which corresponds to Re=1600 based on the cylinder diameter. Spacing ratio between cylinders L/D was 1.5. Instantaneous and averaged velocity fields were presented. Experiments were designed in order to use their results as a test case for future numerical calculations.

Cylinder To Cylinder Balancing Using Intake Valve Actuation

DOEpatents

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.

MONOMIALS AND BASIN CYLINDERS FOR NETWORK DYNAMICS.

PubMed

Austin, Daniel; Dinwoodie, Ian H

We describe methods to identify cylinder sets inside a basin of attraction for Boolean dynamics of biological networks. Such sets are used for designing regulatory interventions that make the system evolve towards a chosen attractor, for example initiating apoptosis in a cancer cell. We describe two algebraic methods for identifying cylinders inside a basin of attraction, one based on the Groebner fan that finds monomials that define cylinders and the other on primary decomposition. Both methods are applied to current examples of gene networks.

MONOMIALS AND BASIN CYLINDERS FOR NETWORK DYNAMICS

PubMed Central

AUSTIN, DANIEL; DINWOODIE, IAN H

2014-01-01

We describe methods to identify cylinder sets inside a basin of attraction for Boolean dynamics of biological networks. Such sets are used for designing regulatory interventions that make the system evolve towards a chosen attractor, for example initiating apoptosis in a cancer cell. We describe two algebraic methods for identifying cylinders inside a basin of attraction, one based on the Groebner fan that finds monomials that define cylinders and the other on primary decomposition. Both methods are applied to current examples of gene networks. PMID:25620893

A characteristic analysis of the fluidic muscle cylinder

NASA Astrophysics Data System (ADS)

Kim, Dong-Soo; Bae, Sang-Kyu; Hong, Sung-In

2005-12-01

The fluidic muscle cylinder consists of an air bellows tube, flanges and lock nuts. It's features are softness of material and motion, simplicity of structure, low production cost and high power efficiency. Recently, unlikely the pneumatic cylinder, the fluidic muscle cylinder without air leakage, stick slip, friction, and seal was developed as a new concept actuator. It has the characteristics such as light weight, low price, high response, durable design, long life, high power, high contraction, which is innovative product fulfilling RT(Robot Technology) which is one of the nation-leading next generation strategy technologies 6T as well as cleanness technology. The application fields of the fluidic muscle cylinder are so various like fatigue tester, brake, accelerator, high technology testing device such as driving simulator, precise position, velocity, intelligent servo actuator under special environment such as load controlling system, and intelligent robot. In this study, we carried out the finite element modeling and analysis about the main design variables such as contraction ration and force, diameter increment of fluidic muscle cylinder. On the basis of finite element analysis, the prototype of fluidic muscle cylinder was manufactured and tested. Finally, we compared the results between the test and the finite element analysis.

A Convenient Storage Rack for Graduated Cylinders

ERIC Educational Resources Information Center

Love, Brian

2004-01-01

An attempt is made to find a solution to the occasional problem of a need for storing large numbers of graduated cylinders in many teaching and research laboratories. A design, which involves the creation of a series of parallel channels that are used to suspend inverted graduated cylinders by their bases, is proposed.

Natural abundant (17) O NMR in a 1.5-T Halbach magnet.

PubMed

Sørensen, Morten K; Bakharev, Oleg N; Jensen, Ole; Nielsen, Niels Chr

2016-06-01

We present mobile, low-field (17) O NMR as a means for monitoring oxygen in liquids. Whereas oxygen is one of the most important elements, oxygen NMR is limited by a poor sensitivity related to low natural abundance and gyro-magnetic ratio of the NMR active (17) O isotope. Here, we demonstrate (17) O NMR detection at a Larmor frequency of 8.74 MHz in a 1.5-T Halbach neodymium magnet with a home-built digital NMR instrument suitable for large-scale production and in-line monitoring applications. The proposed (17) O NMR sensor may be applied for direct, noninvasive measurements of water content in, for example, oil, manure, or food in automated quality or process control. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Label inspection of approximate cylinder based on adverse cylinder panorama

NASA Astrophysics Data System (ADS)

Lin, Jianping; Liao, Qingmin; He, Bei; Shi, Chenbo

2013-12-01

This paper presents a machine vision system for automated label inspection, with the goal to reduce labor cost and ensure consistent product quality. Firstly, the images captured from each single-camera are distorted, since the inspection object is approximate cylindrical. Therefore, this paper proposes an algorithm based on adverse cylinder projection, where label images are rectified by distortion compensation. Secondly, to overcome the limited field of viewing for each single-camera, our method novelly combines images of all single-cameras and build a panorama for label inspection. Thirdly, considering the shake of production lines and error of electronic signal, we design the real-time image registration to calculate offsets between the template and inspected images. Experimental results demonstrate that our system is accurate, real-time and can be applied for numerous real- time inspections of approximate cylinders.

Characteristic analysis and experimental evaluation of artificial pneumatic cylinder

NASA Astrophysics Data System (ADS)

Kim, Dong-Soo; Bae, Sang-Kyu; Choi, Kyung-Hyun

2005-12-01

The fluidic muscle cylinder consists of an air bellows tube, flanges and lock nuts. Its features are softness of material and motion, simplicity of structure, low production cost and high power efficiency. Recently, unlikely the pneumatic cylinder, the fluidic muscle cylinder without air leakage, stick slip, friction, and seal was developed as a new concept actuator. It has the characteristics such as light weight, low price, high response, durable design, long life, high power, high contraction, which is innovative product fulfilling RT(Robot Technology) which is one of the nation-leading next generation strategy technologies 6T as well as cleanness technology. The application fields of the fluidic muscle cylinder are so various like fatigue tester, brake, accelerator, high technology testing device such as driving simulator, precise position, velocity, intelligent servo actuator under special environment such as load controlling system, and intelligent robot. In this study, we carried out the finite element modeling and analysis about the main design variables such as contraction ration and force, diameter increment of fluidic muscle cylinder. On the basis of finite element analysis, the prototype of fluidic muscle cylinder was fabricated and tested. Finally, we compared the results between the test and the finite element analysis.

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.

Coupled Thermo-Mechanical Analyses of Dynamically Loaded Rubber Cylinders

NASA Technical Reports Server (NTRS)

Johnson, Arthur R.; Chen, Tzi-Kang

2000-01-01

A procedure that models coupled thermo-mechanical deformations of viscoelastic rubber cylinders by employing the ABAQUS finite element code is described. Computational simulations of hysteretic heating are presented for several tall and short rubber cylinders both with and without a steel disk at their centers. The cylinders are compressed axially and are then cyclically loaded about the compressed state. The non-uniform hysteretic heating of the rubber cylinders containing a steel disk is presented. The analyses performed suggest that the coupling procedure should be considered for further development as a design tool for rubber degradation studies.

Cylinder Test Specification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richard Catanach; Larry Hill; Herbert Harry

1999-10-01

The purpose of the cylinder testis two-fold: (1) to characterize the metal-pushing ability of an explosive relative to that of other explosives as evaluated by the E{sub 19} cylinder energy and the G{sub 19} Gurney energy and (2) to help establish the explosive product equation-of-state (historically, the Jones-Wilkins-Lee (JWL) equation). This specification details the material requirements and procedures necessary to assemble and fire a typical Los Alamos National Laboratory (LANL) cylinder test. Strict adherence to the cylinder. material properties, machining tolerances, material heat-treatment and etching processes, and high explosive machining tolerances is essential for test-to-test consistency and to maximize radialmore » wall expansions. Assembly and setup of the cylinder test require precise attention to detail, especially when placing intricate pin wires on the cylinder wall. The cylinder test is typically fired outdoors and at ambient temperature.« less

Precision cylinder optics for higher requirements; Techical Digest

NASA Astrophysics Data System (ADS)

Bergner, Dieter; Falkenstorfer, Oliver; Malina, Dirk; Roder, Janett; Schreiner, Roland

2005-05-01

JENOPTIK Laser, Optik, Systeme GmbH (JO L.O.S.) enlarged its product range in the field of cylinder lenses and crystal optics. These components are used in optical measuring technology and in various laser applications. The new cylinder components are a result of the state of the art manufacturing technology. For applications, where the quality of standard cylinders with a surface deviation of PV Lambda/2 to Lambda/5 @632,8nm and tested with a reference glass only is not sufficient, the surface shape can be improved to PV Lambda/10 @632,8nm. The presentation deals with Jenoptik's current state to produce cylinder optics, to reduce remaining surface shape deviations of semi-finished cylinder optics and to test these elements. Based on in-house developed machinery, cylinders are manufactured by means of blocking or drum. The required surface quality in the range of PV Lambda/10 @632,8nm for cylindrical lenses can be reached by computer aided correction using mrf-polishing techniques in connection with an interferometer test set-up. Therefore, the polishing machine is equipped with an additional axis of movement. The interferometer measurement of the residual surface deviation is done by Computer Generated Holograms (CGH), which are designed and manufactured in-house. CGHs from JO L.O.S. for testing cylindrical lenses can be custom designed starting with F#1.0. They are related to the typical rectangular geometry of cylinder components. Using these measurement techniques, testing is no longer the limiting factor in achieving high quality cylindrical surfaces. JO L.O.S. has all the capabilities of effective manufacturing, testing and correcting cylindrical lenses. Latest results achieved in series production are shown.

Precision cylinder optics for higher requirements; Techical Digest

NASA Astrophysics Data System (ADS)

Bergner, Dieter; Falkenstorfer, Oliver; Malina, Dirk; Roder, Janett; Schreiner, Roland

2005-05-01

JENOPTIK Laser, Optik, Systeme GmbH (JO L.O.S.) enlarged its product range in the field of cylinder lenses and crystal optics. These components are used in optical measuring technology and in various laser applications. The new cylinder components are a result of the state of the art manufacturing technology. For applications, where the quality of standard cylinders with a surface deviation of PV~Lambda/2 to ~Lambda/5 @632,8nm and tested with a reference glass only is not sufficient, the surface shape can be improved to PV Lambda/10 @632,8nm. The presentation deals with Jenoptik's current state to produce cylinder optics, to reduce remaining surface shape deviations of semi-finished cylinder optics and to test these elements. Based on in-house developed machinery, cylinders are manufactured by means of blocking or drum. The required surface quality in the range of PV~Lambda/10 @632,8nm for cylindrical lenses can be reached by computer aided correction using mrf-polishing techniques in connection with an interferometer test set-up. Therefore, the polishing machine is equipped with an additional axis of movement. The interferometer measurement of the residual surface deviation is done by Computer Generated Holograms (CGH), which are designed and manufactured in-house. CGHs from JO L.O.S. for testing cylindrical lenses can be custom designed starting with F#1.0. They are related to the typical rectangular geometry of cylinder components. Using these measurement techniques, testing is no longer the limiting factor in achieving high quality cylindrical surfaces. JO L.O.S. has all the capabilities of effective manufacturing, testing and correcting cylindrical lenses. Latest results achieved in series production are shown.

An Experiment in Heat Conduction Using Hollow Cylinders

ERIC Educational Resources Information Center

Ortuno, M.; Marquez, A.; Gallego, S.; Neipp, C.; Belendez, A.

2011-01-01

An experimental apparatus was designed and built to allow students to carry out heat conduction experiments in hollow cylinders made of different materials, as well as to determine the thermal conductivity of these materials. The evolution of the temperature difference between the inner and outer walls of the cylinder as a function of time is…

Incremental Adaptive Fuzzy Control for Sensorless Stroke Control of A Halbach-type Linear Oscillatory Motor

NASA Astrophysics Data System (ADS)

Lei, Meizhen; Wang, Liqiang

2018-01-01

The halbach-type linear oscillatory motor (HT-LOM) is multi-variable, highly coupled, nonlinear and uncertain, and difficult to get a satisfied result by conventional PID control. An incremental adaptive fuzzy controller (IAFC) for stroke tracking was presented, which combined the merits of PID control, the fuzzy inference mechanism and the adaptive algorithm. The integral-operation is added to the conventional fuzzy control algorithm. The fuzzy scale factor can be online tuned according to the load force and stroke command. The simulation results indicate that the proposed control scheme can achieve satisfied stroke tracking performance and is robust with respect to parameter variations and external disturbance.

49 CFR 178.35 - General requirements for specification cylinders.

Code of Federal Regulations, 2011 CFR

2011-10-01

... cylinders made by the billet-piercing process, billets must be inspected and shown to be free from pipe... specific construction design.); (v) Witnessing all tests; (vi) Verify threads by gauge; (vii) Reporting... certifies that the processes of manufacture and heat treatment of cylinders were observed and found...

49 CFR 178.35 - General requirements for specification cylinders.

Code of Federal Regulations, 2014 CFR

2014-10-01

... cylinders made by the billet-piercing process, billets must be inspected and shown to be free from pipe... specific construction design.); (v) Witnessing all tests; (vi) Verify threads by gauge; (vii) Reporting... certifies that the processes of manufacture and heat treatment of cylinders were observed and found...

49 CFR 178.35 - General requirements for specification cylinders.

Code of Federal Regulations, 2013 CFR

2013-10-01

... cylinders made by the billet-piercing process, billets must be inspected and shown to be free from pipe... specific construction design.); (v) Witnessing all tests; (vi) Verify threads by gauge; (vii) Reporting... certifies that the processes of manufacture and heat treatment of cylinders were observed and found...

49 CFR 178.35 - General requirements for specification cylinders.

Code of Federal Regulations, 2012 CFR

2012-10-01

... cylinders made by the billet-piercing process, billets must be inspected and shown to be free from pipe... specific construction design.); (v) Witnessing all tests; (vi) Verify threads by gauge; (vii) Reporting... certifies that the processes of manufacture and heat treatment of cylinders were observed and found...

49 CFR 173.301a - Additional general requirements for shipment of specification cylinders.

Code of Federal Regulations, 2013 CFR

2013-10-01

... gases in specification cylinders. (b) Authorized cylinders not marked with a service pressure. For authorized cylinders not marked with a service pressure, the service pressure is designated as follows: Specification marking Service Pressure psig 3 1800 3E 1800 8 250 (c) Cylinder pressure at 21 °C (70 °F). The...

49 CFR 173.301a - Additional general requirements for shipment of specification cylinders.

Code of Federal Regulations, 2011 CFR

2011-10-01

... gases in specification cylinders. (b) Authorized cylinders not marked with a service pressure. For authorized cylinders not marked with a service pressure, the service pressure is designated as follows: Specification marking Service Pressure psig 3 1800 3E 1800 8 250 (c) Cylinder pressure at 21 °C (70 °F). The...

49 CFR 173.301a - Additional general requirements for shipment of specification cylinders.

Code of Federal Regulations, 2014 CFR

2014-10-01

... gases in specification cylinders. (b) Authorized cylinders not marked with a service pressure. For authorized cylinders not marked with a service pressure, the service pressure is designated as follows: Specification marking Service Pressure psig 3 1800 3E 1800 8 250 (c) Cylinder pressure at 21 °C (70 °F). The...

49 CFR 173.301a - Additional general requirements for shipment of specification cylinders.

Code of Federal Regulations, 2010 CFR

2010-10-01

... gases in specification cylinders. (b) Authorized cylinders not marked with a service pressure. For authorized cylinders not marked with a service pressure, the service pressure is designated as follows: Specification marking Service Pressure psig 3 1800 3E 1800 8 250 (c) Cylinder pressure at 21 °C (70 °F). The...

49 CFR 178.35 - General requirements for specification cylinders.

Code of Federal Regulations, 2010 CFR

2010-10-01

... cylinders made by the billet-piercing process, billets must be inspected and shown to be free from pipe... specific construction design.); (v) Witnessing all tests; (vi) Verify threads by gauge; (vii) Reporting... finished cylinder has been welded by the spinning process, or effected by plugging. (ii) As prescribed in...

Response of Buried Vertically Oriented Cylinders to Dynamic Loading,

DTIC Science & Technology

1980-06-01

BALSARA • , . / ,, _,-, -. 1i S ,LESPONSE OF BURIED VERTICALLY 9RIENTED CYLINDERS 𔃺 .-TO DINAMIC LOADING_ 9AYLE E. LRTOrwW&-N JIIMY P./BALSARA Nk...1.7, 2,8, and 4.0 inches). The end caps for the cylinders consisted of a steel shell filled with high- strength concrete; however, the end caps were...not designed to be test articles. The average concrete compressive strength of the cylinders on test day was 44.0 MPa (6,380 psi). The three DEOT

Modeling flow for modified concentric cylinder rheometer geometry

NASA Astrophysics Data System (ADS)

Ekeruche, Karen; Connelly, Kelly; Kavehpour, H. Pirouz

2016-11-01

Rheology experiments on biological fluids can be difficult when samples are limited in volume, sensitive to degradation, and delicate to extract from tissues. A probe-like geometry has been developed to perform shear creep experiments on biological fluids and to use the creep response to characterize fluid material properties. This probe geometry is a modified concentric cylinder setup, where the gap is large and we assume the inner cylinder rotates in an infinite fluid. To validate this assumption we perform shear creep tests with the designed probe on Newtonian and non-Newtonian fluids and vary the outer cylinder container diameter. We have also created a numerical model based on the probe geometry setup to compare with experimental results at different outer cylinder diameters. A creep test is modeled by applying rotation to the inner cylinder and solving for the deformation of the fluid throughout the gap. Steady state viscosity values are calculated from creep compliance curves and compared between experimental and numerical results.

Carbon fiber reinforced hierarchical orthogrid stiffened cylinder: Fabrication and testing

NASA Astrophysics Data System (ADS)

Wu, Hao; Lai, Changlian; Sun, Fangfang; Li, Ming; Ji, Bin; Wei, Weiyi; Liu, Debo; Zhang, Xi; Fan, Hualin

2018-04-01

To get strong, stiff and light cylindrical shell, carbon fiber reinforced hierarchical orthogrid stiffened cylinders are designed and fabricated. The cylinder is stiffened by two-scale orthogrid. The primary orthogrid has thick and high ribs and contains several sub-orthogrid cells whose rib is much thinner and lower. The primary orthogrid stiffens the bending rigidity of the cylinder to resist the global instability while the sub-orthogrid stiffens the bending rigidity of the skin enclosed by the primary orthogrid to resist local buckling. The cylinder is fabricated by filament winding method based on a silicone rubber mandrel with hierarchical grooves. Axial compression tests are performed to reveal the failure modes. With hierarchical stiffeners, the cylinder fails at skin fracture and has high specific strength. The cylinder will fail at end crushing if the end of the cylinder is not thickened. Global instability and local buckling are well restricted by the hierarchical stiffeners.

Enrichment Assay Methods Development for the Integrated Cylinder Verification System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Leon E.; Misner, Alex C.; Hatchell, Brian K.

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 eachmore » 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.« less

Integrated two-cylinder liquid piston Stirling engine

NASA Astrophysics Data System (ADS)

Yang, Ning; Rickard, Robert; Pluckter, Kevin; Sulchek, Todd

2014-10-01

Heat engines utilizing the Stirling cycle may run on low temperature differentials with the capacity to function at high efficiency due to their near-reversible operation. However, current approaches to building Stirling engines are laborious and costly. Typically the components are assembled by hand and additional components require a corresponding increase in manufacturing complexity, akin to electronics before the integrated circuit. We present a simple and integrated approach to fabricating Stirling engines with precisely designed cylinders. We utilize computer aided design and one-step, planar machining to form all components of the engine. The engine utilizes liquid pistons and displacers to harness useful work from heat absorption and rejection. As a proof of principle of the integrated design, a two-cylinder engine is produced and characterized and liquid pumping is demonstrated.

Engine Cylinder Temperature Control

DOEpatents

Kilkenny, Jonathan Patrick; Duffy, Kevin Patrick

2005-09-27

A method and apparatus for controlling a temperature in a combustion cylinder in an internal combustion engine. The cylinder is fluidly connected to an intake manifold and an exhaust manifold. The method and apparatus includes increasing a back pressure associated with the exhaust manifold to a level sufficient to maintain a desired quantity of residual exhaust gas in the cylinder, and varying operation of an intake valve located between the intake manifold and the cylinder to an open duration sufficient to maintain a desired quantity of fresh air from the intake manifold to the cylinder, wherein controlling the quantities of residual exhaust gas and fresh air are performed to maintain the temperature in the cylinder at a desired level.

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.

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.

4. View showing cylinder end of two, cylinder, compound Corliss ...

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

4. View showing cylinder end of two, cylinder, compound Corliss steam engine with tandem air compressor. - International Smelting & Refining Company, Tooele Smelter, Powerhouse, State Route 178, Tooele, Tooele County, UT

Integrated two-cylinder liquid piston Stirling engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Ning; Rickard, Robert; Pluckter, Kevin

2014-10-06

Heat engines utilizing the Stirling cycle may run on low temperature differentials with the capacity to function at high efficiency due to their near-reversible operation. However, current approaches to building Stirling engines are laborious and costly. Typically the components are assembled by hand and additional components require a corresponding increase in manufacturing complexity, akin to electronics before the integrated circuit. We present a simple and integrated approach to fabricating Stirling engines with precisely designed cylinders. We utilize computer aided design and one-step, planar machining to form all components of the engine. The engine utilizes liquid pistons and displacers to harnessmore » useful work from heat absorption and rejection. As a proof of principle of the integrated design, a two-cylinder engine is produced and characterized and liquid pumping is demonstrated.« less

Passively Enhancing Convection Heat Transfer Around Cylinder Using Shrouds

NASA Astrophysics Data System (ADS)

Samaha, Mohamed A.; Kahwaji, Ghalib Y.

2017-11-01

Natural convection heat transfer around a horizontal cylinder has received considerable attention through decades since it has been used in several viable applications. However, investigations into passively enhancement of the free convective cooling using external walls and chimney effect are lacking. In this work, a numerical simulation to study natural convection from a horizontal cylinder configured with semicircular shrouds with an expended chimney is employed. The fluid flow and convective heat transfer around the cylinder are modeled. The bare cylinder is also simulated for comparison. The present study are aimed at improving our understanding of the parameters advancing the free convective cooling of the cylinder implemented with the shrouds configuration. For validation, the present results for the bare tube are compared with data reported in the literature. The numerical simulations indicate that applying the shrouds configuration with extended chimney to a tube promotes the convection heat transfer from the cylinder. Such a method is less expensive and simpler in design than other configurations (e.g. utilizing extended surfaces, fins), making the technology more practical for industrial productions, especially for cooling systems. Dubai Silicon Oasis Authority (DSOA) Grants.

Heat storage capability of a rolling cylinder using Glauber's salt

NASA Technical Reports Server (NTRS)

Herrick, C. S.; Zarnoch, K. P.

1980-01-01

The rolling cylinder phase change heat storage concept was developed to the point where a prototype design is completed and a cost analysis is prepared. A series of experimental and analytical tasks are defined to establish the thermal, mechanical, and materials behavior of rolling cylinder devices. These tasks include: analyses of internal and external heat transfer; performance and lifetime testing of the phase change materials; corrosion evaluation; development of a mathematical model; and design of a prototype and associated test equipment.

Carbon-carbon cylinder block

NASA Technical Reports Server (NTRS)

Ransone, Philip O. (Inventor)

1995-01-01

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 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.

Finite deformations in pressurized thick-walled circular cylinder with steady state temperature

NASA Astrophysics Data System (ADS)

Sharma, Sanjeev; Sharma, Richa

2017-10-01

In this paper finite elastic and plastic stresses have been investigated using the concept of transition theory with the use of generalized strain measure i.e. nonlinear terms in the displacement are also included which are not included in classical theory. In this paper, we analyze the impact of temperature and pressure on the circular cylinder which is the cause of failure of cylinder. It has been noticed from the results that pressure and temperature play a significant role in the failure of the cylinder. It has been noticed that cylinder made up of the material whose compressibility is at the higher side is best for the designing purpose as compared to cylinder with less compressible material.

Evaluation of Analysis Techniques for Fluted-Core Sandwich Cylinders

NASA Technical Reports Server (NTRS)

Lovejoy, Andrew E.; Schultz, Marc R.

2012-01-01

Buckling-critical launch-vehicle structures require structural concepts that have high bending stiffness and low mass. Fluted-core, also known as truss-core, sandwich construction is one such concept. In an effort to identify an analysis method appropriate for the preliminary design of fluted-core cylinders, the current paper presents and compares results from several analysis techniques applied to a specific composite fluted-core test article. The analysis techniques are evaluated in terms of their ease of use and for their appropriateness at certain stages throughout a design analysis cycle (DAC). Current analysis techniques that provide accurate determination of the global buckling load are not readily applicable early in the DAC, such as during preliminary design, because they are too costly to run. An analytical approach that neglects transverse-shear deformation is easily applied during preliminary design, but the lack of transverse-shear deformation results in global buckling load predictions that are significantly higher than those from more detailed analysis methods. The current state of the art is either too complex to be applied for preliminary design, or is incapable of the accuracy required to determine global buckling loads for fluted-core cylinders. Therefore, it is necessary to develop an analytical method for calculating global buckling loads of fluted-core cylinders that includes transverse-shear deformations, and that can be easily incorporated in preliminary design.

Thermo-Mechanical Analyses of Dynamically Loaded Rubber Cylinders

NASA Technical Reports Server (NTRS)

Johnson, Arthur R.; Chen, Tzi-Kang

2002-01-01

Thick rubber components are employed by the Army to carry large loads. In tanks, rubber covers road wheels and track systems to protect roadways. It is difficult for design engineers to simulate the details of the hysteretic heating for large strain viscoelastic deformations. In this study, an approximation to the viscoelastic energy dissipated per unit time is investigated for use in estimating mechanically induced viscoelastic heating. Coupled thermo-mechanical simulations of large cyclic deformations of rubber cylinders are presented. The cylinders are first compressed axially and then cyclically loaded about the compressed state. Details of the algorithm and some computational issues are discussed. The coupled analyses are conducted for tall and short rubber cylinders both with and without imbedded metal disks.

30 CFR 75.1106-2 - Transportation of liquefied and nonliquefied compressed gas cylinders; requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... underground coal mine shall be: (1) Placed securely in devices designed to hold the cylinder in place during transit on self-propelled equipment or belt conveyors; (2) Disconnected from all hoses and gages; (3... containers which are specifically designed for holding such cylinders. (c) Liquefied and nonliquefied...

Topology optimized permanent magnet systems

NASA Astrophysics Data System (ADS)

Bjørk, R.; Bahl, C. R. H.; Insinga, A. R.

2017-09-01

Topology optimization of permanent magnet systems consisting of permanent magnets, high permeability iron and air is presented. An implementation of topology optimization for magnetostatics is discussed and three examples are considered. The Halbach cylinder is topology optimized with iron and an increase of 15% in magnetic efficiency is shown. A topology optimized structure to concentrate a homogeneous field is shown to increase the magnitude of the field by 111%. Finally, a permanent magnet with alternating high and low field regions is topology optimized and a Λcool figure of merit of 0.472 is reached, which is an increase of 100% compared to a previous optimized design.

Enhancement of polarizabilities of cylinders with cylinder-slab resonances

PubMed Central

Xiao, Meng; Huang, Xueqin; Liu, H.; Chan, C. T.

2015-01-01

If an object is very small in size compared with the wavelength of light, it does not scatter light efficiently. It is hence difficult to detect a very small object with light. We show using analytic theory as well as full wave numerical calculation that the effective polarizability of a small cylinder can be greatly enhanced by coupling it with a superlens type metamaterial slab. This kind of enhancement is not due to the individual resonance effect of the metamaterial slab, nor due to that of the object, but is caused by a collective resonant mode between the cylinder and the slab. We show that this type of particle-slab resonance which makes a small two-dimensional object much “brighter” is actually closely related to the reverse effect known in the literature as “cloaking by anomalous resonance” which can make a small cylinder undetectable. We also show that the enhancement of polarizability can lead to strongly enhanced electromagnetic forces that can be attractive or repulsive, depending on the material properties of the cylinder. PMID:25641391

Anaesthesia Gas Supply: Gas Cylinders

PubMed Central

Srivastava, Uma

2013-01-01

Invention of oxygen cylinder was one of the most important developments in the field of medical practice. Oxygen and other gases were compressed and stored at high pressure in seamless containers constructed from hand-forged steel in1880. Materials technology has continued to evolve and now medical gas cylinders are generally made of steel alloys or aluminum. The filling pressure as well as capacity has increased considerably while at the same time the weight of cylinders has reduced. Today oxygen cylinder of equivalent size holds a third more oxygen but weighs about 20 kg less. The cylinders are of varying sizes and are color coded. They are tested at regular intervals by the manufacturer using hydraulic, impact, and tensile tests. The top end of the cylinder is fitted with a valve with a variety of number and markings stamped on it. Common valve types include: Pin index valve, bull nose, hand wheel and integral valve. The type of valve varies with cylinder size. Small cylinders have a pin index valve while large have a bull nose type. Safety features in the cylinder are: Color coding, pin index, pressure relief device, Bodok seal, and label attached etc., Safety rules and guidelines must be followed during storage, installation and use of cylinders to ensure safety of patients, hospital personnel and the environment. PMID:24249883

Anaesthesia gas supply: gas cylinders.

PubMed

Srivastava, Uma

2013-09-01

Invention of oxygen cylinder was one of the most important developments in the field of medical practice. Oxygen and other gases were compressed and stored at high pressure in seamless containers constructed from hand-forged steel in1880. Materials technology has continued to evolve and now medical gas cylinders are generally made of steel alloys or aluminum. The filling pressure as well as capacity has increased considerably while at the same time the weight of cylinders has reduced. Today oxygen cylinder of equivalent size holds a third more oxygen but weighs about 20 kg less. The cylinders are of varying sizes and are color coded. They are tested at regular intervals by the manufacturer using hydraulic, impact, and tensile tests. The top end of the cylinder is fitted with a valve with a variety of number and markings stamped on it. Common valve types include: Pin index valve, bull nose, hand wheel and integral valve. The type of valve varies with cylinder size. Small cylinders have a pin index valve while large have a bull nose type. Safety features in the cylinder are: Color coding, pin index, pressure relief device, Bodok seal, and label attached etc., Safety rules and guidelines must be followed during storage, installation and use of cylinders to ensure safety of patients, hospital personnel and the environment.

Gas Cylinder Safety, Course 9518

DOE Office of Scientific and Technical Information (OSTI.GOV)

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).

Dynamic Measurement of Extra Long Stroke Cylinder in the Pneumatic System

NASA Astrophysics Data System (ADS)

Chang, Ho; Lan, Chou-wei; Chen, Liang-Chia

2006-10-01

This paper sets up the measure and control system of the dynamic characteristics of the extra long stroke cylinder. In the different types of the control conditions (e.g. different control law, operating pressure and direct control valves), using the measure and control system to measure the relation between the pressure and the velocity of the motion of the long stroke cylinder and to observe the stick slip phenomenon of the motion of the long stroke cylinder. In the innovate measurement system, two pressure sensors are set on the long stroke cylinder to measure the difference of the pressure between the inlet and the exhaust of the long stroke cylinder. In additions, a draw line encoder is set on the system to measure the position and the velocity of the motion of the long stroke cylinder. The measuring data of the measure system is transferred to the computer via A/D interface card and counter card, and Home-made program of Haptic Interface Device is used to control the system, saving the data of the motion of the long stroke cylinder. The system uses different types of direction control valve to control the motion of the long stroke cylinder and compares the difference of the motion of the long stroke cylinder. The results show that the motion of the cylinder that pauses in the middle of the cylinder stroke and causes the stick slip phenomenon is more violent than the stick slip phenomenon in other position. When the length of the pause time reaches the some range, the acceleration of the motion of the cylinder will be rised substantially. This paper not only focuses on the testing method of the dynamic characteristics of the motion of the long stroke cylinder, but also includes the analysis of the dynamic characteristics of the motion of the long stroke cylinder. It provides the data of the dynamic characteristics of the motion of the long stroke cylinder to improve and design the pneumatic system of the long stroke cylinder.

Prediction model of velocity field around circular cylinder over various Reynolds numbers by fusion convolutional neural networks based on pressure on the cylinder

NASA Astrophysics Data System (ADS)

Jin, Xiaowei; Cheng, Peng; Chen, Wen-Li; Li, Hui

2018-04-01

A data-driven model is proposed for the prediction of the velocity field around a cylinder by fusion convolutional neural networks (CNNs) using measurements of the pressure field on the cylinder. The model is based on the close relationship between the Reynolds stresses in the wake, the wake formation length, and the base pressure. Numerical simulations of flow around a cylinder at various Reynolds numbers are carried out to establish a dataset capturing the effect of the Reynolds number on various flow properties. The time series of pressure fluctuations on the cylinder is converted into a grid-like spatial-temporal topology to be handled as the input of a CNN. A CNN architecture composed of a fusion of paths with and without a pooling layer is designed. This architecture can capture both accurate spatial-temporal information and the features that are invariant of small translations in the temporal dimension of pressure fluctuations on the cylinder. The CNN is trained using the computational fluid dynamics (CFD) dataset to establish the mapping relationship between the pressure fluctuations on the cylinder and the velocity field around the cylinder. Adam (adaptive moment estimation), an efficient method for processing large-scale and high-dimensional machine learning problems, is employed to implement the optimization algorithm. The trained model is then tested over various Reynolds numbers. The predictions of this model are found to agree well with the CFD results, and the data-driven model successfully learns the underlying flow regimes, i.e., the relationship between wake structure and pressure experienced on the surface of a cylinder is well established.

Numerical simulation of VAWT on the effects of rotation cylinder

NASA Astrophysics Data System (ADS)

Xing, Shuda; Cao, Yang; Ren, Fuji

2017-06-01

Based on Finite Element Analysis Method, studying on Vertical Axis Wind Turbine (VAWT) which is added rotating cylinder in front of its air foils, especially focusing on the analysis of NACA6 series air foils about variation of lift to drag ratio. Choosing the most suitable blades with rotary cylinder added on leading edge. Analysis indicates that the front rotating cylinders on the VAWT is benefit to lift rise and drag fall. The most suitable air foil whose design lift coefficient is 0.8, the blades relative thickness is 20%, and the optimistic tip speed ratio is about 7.

Development status on a TPV cylinder for combined heat and electric power for the home

NASA Astrophysics Data System (ADS)

Fraas, Lewis; Samaras, John; Huang, Han-Xiang; Seal, Michael; West, Edward

1999-03-01

Several first-generation water-cooled TPV cylinders have been built and tested. The existing units contain 380 GaSb cells mounted on 20 circuits; the design and test results on these photovoltaic converter arrays are presented here. Tested with a 1600 °C glowbar, one of these cylinders generated 990 Watts from a cell active area of 396 cm2, which is an electric power density of 2.5 Watts per cm2. A second-generation design is presented, using a new shingled circuit assembly. These shingled circuits allow for a slightly larger cylinder design with nearly double the cell active area. Using a SiC emitter operating at 1425 °C, this second-generation cylinder should produce over 1.5 kW of power with improved efficiency.

Multi-directional electromagnetic vibration energy harvester using circular Halbach array

NASA Astrophysics Data System (ADS)

Qiu, Jing; Liu, Xin; Hu, Zhenwen; Chang, Qijie; Gao, Yuan; Yang, Jin; Wen, Jing; Tang, Xiaosheng; Hu, Wei

2017-05-01

In this paper, a multi-directional electromagnetic vibration energy harvester (EVEH) using the circular Halbach array (HA) is presented based on the Faraday's law of electromagnetic induction. The circular HA is a specific arrangement of permanent magnets which could concentrate the magnetic field inside the circular array by a certain rule, while reduce the magnetic field outside the circular array to almost zero at the same time. The HA could break through the limitation of the related published vibration energy harvesters that could work in only one single direction. Thus, it could optimize the collecting efficiency. The experimental results show that the presented harvester could generate considerable electric output power in all vibrating directions. An optimal output power is 9.32 mW at a resonant frequency of 15.40 Hz with an acceleration of 0.5 g (with g=9.8 m/s2) across a 700-turn coil in the vibrating direction of 90°, which is 1.53 times than the minimum optimal one in the direction of 45°. The EVEH using the circular HA could work in all directions and generate considerable electric output power, which validates the feasibility of the EVEH that works in all directions and is beneficial for improving the practical application.

Elastic torsional buckling of thin-walled composite cylinders

NASA Technical Reports Server (NTRS)

Marlowe, D. E.; Sushinsky, G. F.; Dexter, H. B.

1974-01-01

The elastic torsional buckling strength has been determined experimentally for thin-walled cylinders fabricated with glass/epoxy, boron/epoxy, and graphite/epoxy composite materials and composite-reinforced aluminum and titanium. Cylinders have been tested with several unidirectional-ply orientations and several cross-ply layups. Specimens were designed with diameter-to-thickness ratios of approximately 150 and 300 and in two lengths of 10 in. and 20 in. The results of these tests were compared with the buckling strengths predicted by the torsional buckling analysis of Chao.

Finite element analysis and experiment on high pressure apparatus with split cylinder

NASA Astrophysics Data System (ADS)

Zhao, Liang; Li, Mingzhe; Yang, Yunfei; Wang, Bolong; Li, Yi

2017-07-01

Ultra-high pressure belt-type die was designed with a large sample volume prism cavity and a split cylinder which was divided into eight segments to eliminate circumferential stress. The cylinder of this type die has no cambered surface on inner wall, and the inner hole is a hexagonal prism-type cavity. The divided bodies squeeze with each other, providing the massive support and lateral support effect of the cylinder. Simulation results indicate that the split cylinder with the prism cavity possesses much smaller stress and more uniform stress distribution. The split cylinder with the prism cavity has been shown to bear larger compressive stresses in radial, circumferential and axial directions due to its structure, and tungsten carbide is most effective in pure compression so this type cylinder could bear higher pressure. Experimental results prove that the high pressure apparatus with a prism-type cavity could bear higher pressure. The apparatus with a prism cavity could bear 52.2% more pressure than the belt-type die.

Tandem Cylinder Noise Predictions

NASA Technical Reports Server (NTRS)

Lockard, 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

4 x 8 inch concrete cylinders versus 6 x 12 cylinders.

DOT National Transportation Integrated Search

1984-01-01

Laboratory and field investigations were conducted to compare the compressive strengths obtained for 4 x 8 in. (100 x 200 mm) cylinders with those for standard 6 x 12 in. (150 x 300 mm) cylinders, both made with aggregate having a nominal maximum siz...

Design fabrication and nondestructive testing of six experimental AGCarb/Intermold 3 cylinder assemblies

NASA Technical Reports Server (NTRS)

Thacher, E. F.

1972-01-01

Six subscale Intermold cylinder assemblies with a total of twelve different concepts for transition to AGCarb were fabricated. Three of the cylinder assemblies were made by helically winding the hoop fibers and three were of orthogonal configuration. The fabrication process is summarized and details of each manufacturing method are given. The objectives of the test program were to: (1) demonstrate the fabricability of the Intermold 3 subscale flanges, (2) produce an integral transition from Intermold 3 to AGCarb material, (3) define a workable manufacturing process, and (4) identify a best suited inspection method. The objectives were met and the results are described.

Hydroelastic analysis of surface wave interaction with concentric porous and flexible cylinder systems

NASA Astrophysics Data System (ADS)

Mandal, S.; Datta, N.; Sahoo, T.

2013-10-01

The present study deals with the hydroelastic analysis of gravity wave interaction with concentric porous and flexible cylinder systems, in which the inner cylinder is rigid and the outer cylinder is porous and flexible. The problems are analyzed in finite water depth under the assumption of small amplitude water wave theory and structural response. The cylinder configurations in the present study are namely (a) surface-piercing truncated cylinders, (b) bottom-touching truncated cylinders and (c) complete submerged cylinders extended from free surface to bottom. As special cases of the concentric cylinder system, wave diffraction by (i) porous flexible cylinder and (ii) flexible floating cage with rigid bottom are analyzed. The scattering potentials are evaluated using Fourier-Bessel series expansion method and the least square approximation method. The convergence of the double series is tested numerically to determine the number of terms in the Fourier-Bessel series expansion. The effects of porosity and flexibility of the outer cylinder, in attenuating the hydrodynamic forces and dynamic overturning moments, are analyzed for various cylinder configurations and wave characteristics. A parametric study with respect to wave frequency, ratios of inner-to-outer cylinder radii, annular spacing between the two cylinders and porosities is done. In order to understand the flow distribution around the cylinders, contour plots are provided. The findings of the present study are likely to be of immense help in the design of various types of marine structures which can withstand the wave loads of varied nature in the marine environment. The theory can be easily extended to deal with a large class of problems associated with acoustic wave interaction with flexible porous structures.

An online ID identification system for liquefied-gas cylinder plant

NASA Astrophysics Data System (ADS)

He, Jin; Ding, Zhenwen; Han, Lei; Zhang, Hao

2017-11-01

An automatic ID identification system for gas cylinders' online production was developed based on the production conditions and requirements of the Technical Committee for Standardization of Gas Cylinders. A cylinder ID image acquisition system was designed to improve the image contrast of ID regions on gas cylinders against the background. Then the ID digits region was located by the CNN template matching algorithm. Following that, an adaptive threshold method based on the analysis of local average grey value and standard deviation was proposed to overcome defects of non-uniform background in the segmentation results. To improve the single digit identification accuracy, two BP neural networks were trained respectively for the identification of all digits and the easily confusable digits. If the single digit was classified as one of confusable digits by the former BP neural network, it was further tested by the later one, and the later result was taken as the final identification result of this single digit. At last, the majority voting was adopted to decide the final identification result for the 6-digit cylinder ID. The developed system was installed on a production line of a liquefied-petroleum-gas cylinder plant and worked in parallel with the existing weighing step on the line. Through the field test, the correct identification rate for single ID digit was 94.73%, and none of the tested 2000 cylinder ID was misclassified through the majority voting.

Enhancing fatigue life of cylinder-crown integrated structure by optimizing dimension

NASA Astrophysics Data System (ADS)

Zhang, Weiwei; Wang, Xiaosong; Wang, Zhongren; Yuan, Shijian

2015-03-01

Cylinder-crown integrated hydraulic press (CCIHP) is a new press structure. The hemispherical hydraulic cylinder also functions as a main portion of crown, which has lower weight and higher section modulus compared with the conventional hydraulic cylinder and press crown. As a result, the material strength capacity is better utilized. During the engineering design of cylinder-crown integrated structure, in order to increase the fatigue life, structural optimization on the basis of the adaptive macro genetic algorithms (AMGA) is first conducted to both reduce weight and decrease peak stress. It is shown that the magnitude of the maximum principal stress is decreased by 28.6%, and simultaneously the total weight is reduced by 4.4%. Subsequently, strain-controlled fatigue test is carried out, and the stress-strain hysteresis loops and cyclic hardening curve are obtained. Based on linear fit, the fatigue properties are calculated and used for the fatigue life prediction. It is shown that the predicted fatigue life is significantly increased from 157000 to 1070000 cycles after structural optimization. Finally, according to the optimization design, a 6300 kN CCIHP has been manufactured, and priority application has been also suggested.

An investigation of the fluid-structure interaction of piston/cylinder interface

NASA Astrophysics Data System (ADS)

Pelosi, Matteo

The piston/cylinder lubricating interface represents one of the most critical design elements of axial piston machines. Being a pure hydrodynamic bearing, the piston/cylinder interface fulfills simultaneously a bearing and sealing function under oscillating load conditions. Operating in an elastohydrodynamic lubrication regime, it also represents one of the main sources of power loss due to viscous friction and leakage flow. An accurate prediction of the time changing tribological interface characteristics in terms of fluid film thickness, dynamic pressure field, load carrying ability and energy dissipation is necessary to create more efficient interface designs. The aim of this work is to deepen the understanding of the main physical phenomena defining the piston/cylinder fluid film and to discover the impact of surface elastic deformations and heat transfer on the interface behavior. For this purpose, a unique fully coupled multi-body dynamics model has been developed to capture the complex fluid-structure interaction phenomena affecting the non-isothermal fluid film conditions. The model considers the squeeze film effect due to the piston micro-motion and the change in fluid film thickness due to the solid boundaries elastic deformations caused by the fluid film pressure and by the thermal strain. The model has been verified comparing the numerical results with measurements taken on special designed test pumps. The fluid film calculated dynamic pressure and temperature fields have been compared. Further validation has been accomplished comparing piston/cylinder axial viscous friction forces with measured data. The model has been used to study the piston/cylinder interface behavior of an existing axial piston unit operating at high load conditions. Numerical results are presented in this thesis.

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.

Reducing cylinder drag by adding a plate

NASA Astrophysics Data System (ADS)

Frolov, Vladimir A.; Kozlova, Anna S.

2017-10-01

Reducing the drag of bodies is a central problem of modern aerohydrodynamics. The paper presents theoretical and experimental studies of a new method for reducing the drag of a circular cylinder. To reduce the drag we propose to install a flat plate along the flow in front of the cylinder. The theoretical investigation of the drag was carried out using FlowSimulation software. An experimental study of the body drag was performed in an open wind tunnel. The drag coefficient results of the cylinder depended on the different locations of the flat plate relative to the cylinder. The following geometric characteristics of the cylinder/plate are studied: the width of the gap between the cylinder and the plate and the meridional angle of the plate with respect to the cylinder. On the basis of Numerical and Physical Modeling, the values of the drag coefficient for the cylinder/plate are presented. The results included establishment the locations of the cylinder/plate which give the value of the drag coefficient for the combination of the two bodies. That total drag coefficient of the cylinder/plate can be less than the cylinder alone.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

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 tomore » 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.« less

Buckling behavior of composite cylinders subjected to compressive loading

NASA Technical Reports Server (NTRS)

Carri, R. L.

1973-01-01

Room temperature compressive buckling strengths of eight cylinders, four boron-epoxy and four boron-epoxy reinforced-titanium, with diameter to thickness ratios ranging between 40 and 67 are determined experimentally and compared with analytical predictions. Numerical buckling strengths are presented for Donnell's, Flugge's and Sanders' shell theories for anisotropic and orthotropic material cases. Comparison of analytical predictions with experimental results indicates good agreement and the recommended correlation factor suggested in the literature is applicable for design. For the cylinders tested, the correlation between experiment and theory ranged from 0.73 to 0.97.

Detection of cylinder unbalance from Bayesian inference combining cylinder pressure and vibration block measurement in a Diesel engine

NASA Astrophysics Data System (ADS)

Nguyen, Emmanuel; Antoni, Jerome; Grondin, Olivier

2009-12-01

In the automotive industry, the necessary reduction of pollutant emission for new Diesel engines requires the control of combustion events. This control is efficient provided combustion parameters such as combustion occurrence and combustion energy are relevant. Combustion parameters are traditionally measured from cylinder pressure sensors. However this kind of sensor is expensive and has a limited lifetime. Thus this paper proposes to use only one cylinder pressure on a multi-cylinder engine and to extract combustion parameters from the other cylinders with low cost knock sensors. Knock sensors measure the vibration circulating on the engine block, hence they do not all contain the information on the combustion processes, but they are also contaminated by other mechanical noises that disorder the signal. The question is how to combine the information coming from one cylinder pressure and knock sensors to obtain the most relevant combustion parameters in all engine cylinders. In this paper, the issue is addressed trough the Bayesian inference formalism. In that cylinder where a cylinder pressure sensor is mounted, combustion parameters will be measured directly. In the other cylinders, they will be measured indirectly from Bayesian inference. Experimental results obtained on a four cylinder Diesel engine demonstrate the effectiveness of the proposed algorithm toward that purpose.

Focal surfaces of hyperbolic cylinders

NASA Astrophysics Data System (ADS)

Georgiev, Georgi Hristov; Pavlov, Milen Dimov

2017-12-01

Cylindrical surfaces have many applications in geometric modeling, architecture and other branches of engineering. In this paper, we describe two cylindrical surfaces associated to a given hyperbolic cylinder. The first one is a focal surface which is determined by reciprocal principle curvature of the hyperbolic cylinder. The second one is a generalized focal surface obtained by reciprocal mean curvature of the same hyperbolic cylinder. In particular, we show that each of these surfaces admits three different parametric representations. As consequence, it is proved that the focal and generalized focal surfaces of the hyperbolic cylinder are rational surfaces. An illustrative example is included.

Failure analysis of thick composite cylinders under external pressure

NASA Technical Reports Server (NTRS)

Caiazzo, A.; Rosen, B. W.

1992-01-01

Failure of thick section composites due to local compression strength and overall structural instability is treated. Effects of material nonlinearity, imperfect fiber architecture, and structural imperfections upon anticipated failure stresses are determined. Comparisons with experimental data for a series of test cylinders are described. Predicting the failure strength of composite structures requires consideration of stability and material strength modes of failure using linear and nonlinear analysis techniques. Material strength prediction requires the accurate definition of the local multiaxial stress state in the material. An elasticity solution for the linear static analysis of thick anisotropic cylinders and rings is used herein to predict the axisymmetric stress state in the cylinders. Asymmetric nonlinear behavior due to initial cylinder out of roundness and the effects of end closure structure are treated using finite element methods. It is assumed that local fiber or ply waviness is an important factor in the initiation of material failure. An analytical model for the prediction of compression failure of fiber composites, which includes the effects of fiber misalignments, matrix inelasticity, and multiaxial applied stresses is used for material strength calculations. Analytical results are compared to experimental data for a series of glass and carbon fiber reinforced epoxy cylinders subjected to external pressure. Recommendations for pretest characterization and other experimental issues are presented. Implications for material and structural design are discussed.

Collapse Pressure Analysis of Transversely Isotropic Thick-Walled Cylinder Using Lebesgue Strain Measure and Transition Theory

PubMed Central

Aggarwal, A. K.; Sharma, Richa; Sharma, Sanjeev

2014-01-01

The objective of this paper is to provide guidance for the design of the thick-walled cylinder made up of transversely isotropic material so that collapse of cylinder due to influence of internal and external pressure can be avoided. The concept of transition theory based on Lebesgue strain measure has been used to simplify the constitutive equations. Results have been analyzed theoretically and discussed numerically. From this analysis, it has been concluded that, under the influence of internal and external pressure, circular cylinder made up of transversely isotropic material (beryl) is on the safer side of the design as compared to the cylinders made up of isotropic material (steel). This is because of the reason that percentage increase in effective pressure required for initial yielding to become fully plastic is high for beryl as compared to steel which leads to the idea of “stress saving” that reduces the possibility of collapse of thick-walled cylinder due to internal and external pressure. PMID:24523632

Numerical investigation of flow past 17-cylinder array of square cylinders

NASA Astrophysics Data System (ADS)

Shams-ul-Islam, Nazeer, Ghazala; Ying, Zhou Chao

2018-06-01

In this work, flow past 17-cylinder array is simulated using the two-dimensional lattice Boltzmann method. Effect of gap spacings (0.5 ≤ gx* ≤ 3, 0.5 ≤ gy* ≤ 3) and Reynolds number (Re = 75 - 150) is analyzed in details. Results are presented in the form of vorticity contours plots, time-histories of drag and lift coefficients and power spectrum of lift coefficient. Six distinct flow regimes are identified for different gap spacings and Reynolds numbers: steady flow regime, single bluff body flow regime, non-fully developed flow regime, chaotic flow regime, quasi-periodic-I flow regime and quasi-periodic-II flow regime. Chaotic flow regime is the mostly observed flow regime while the single bluff body flow regime rarely occurs for this configuration. It is observed that drag force along each cylinder in 17-cylinder array decreases in the streamwise direction for fixed Reynold number and gap spacing. C1 and C2 cylinders experience the maximum drag at small gap spacing and Reynolds number. Also the Reynolds number is found to be more effective on flow characteristics as compared to gap spacings.

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

NASA Technical Reports Server (NTRS)

Davis, R. C.

1982-01-01

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

Analysis of automobile engine cylinder pressure and rotation speed from engine body vibration signal

NASA Astrophysics Data System (ADS)

Wang, Yuhua; Cheng, Xiang; Tan, Haishu

2016-01-01

In order to improve the engine vibration signal process method for the engine cylinder pressure and engine revolution speed measurement instrument, the engine cylinder pressure varying with the engine working cycle process has been regarded as the main exciting force for the engine block forced vibration. The forced vibration caused by the engine cylinder pressure presents as a low frequency waveform which varies with the cylinder pressure synchronously and steadily in time domain and presents as low frequency high energy discrete humorous spectrum lines in frequency domain. The engine cylinder pressure and the rotation speed can been extract form the measured engine block vibration signal by low-pass filtering analysis in time domain or by FFT analysis in frequency domain, the low-pass filtering analysis in time domain is not only suitable for the engine in uniform revolution condition but also suitable for the engine in uneven revolution condition. That provides a practical and convenient way to design motor revolution rate and cylinder pressure measurement instrument.

Massless rotating fermions inside a cylinder

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ambruş, Victor E., E-mail: victor.ambrus@gmail.com; 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, whilemore » the spectral boundary condition is nonlocal.« less

Efficient visual grasping alignment for cylinders

NASA Technical Reports Server (NTRS)

Nicewarner, Keith E.; Kelley, Robert B.

1992-01-01

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.

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.

Effect of Catalytic Cylinders on Autothermal Reforming of Methane for Hydrogen Production in a Microchamber Reactor

PubMed Central

Yan, Yunfei; Guo, Hongliang; Zhang, Li; Zhu, Junchen; Yang, Zhongqing; Tang, Qiang; Ji, Xin

2014-01-01

A new multicylinder microchamber reactor is designed on autothermal reforming of methane for hydrogen production, and its performance and thermal behavior, that is, based on the reaction mechanism, is numerically investigated by varying the cylinder radius, cylinder spacing, and cylinder layout. The results show that larger cylinder radius can promote reforming reaction; the mass fraction of methane decreased from 26% to 21% with cylinder radius from 0.25 mm to 0.75 mm; compact cylinder spacing corresponds to more catalytic surface and the time to steady state is decreased from 40 s to 20 s; alteration of staggered and aligned cylinder layout at constant inlet flow rates does not result in significant difference in reactor performance and it can be neglected. The results provide an indication and optimize performance of reactor; it achieves higher conversion compared with other reforming reactors. PMID:25097877

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.

The structural response of unsymmetrically laminated composite cylinders

NASA Technical Reports Server (NTRS)

Butler, T. A.; Hyer, M. W.

1989-01-01

The responses of an unsymmetrically laminated fiber-reinforced composite cylinder to an axial compressive load, a torsional load, and the temperature change associated with cooling from the processing temperature to the service temperature are investigated. These problems are considered axisymmetric and the response is studied in the context of linear elastic material behavior and geometrically linear kinematics. Four different laminates are studied: a general unsymmetric laminate; two unsymmetric but more conventional laminates; and a conventional quasi-isotropic symmetric laminate. The responses based on closed-form solutions for different boundary conditions are computed and studied in detail. Particular emphasis is directed at understanding the influence of elastic couplings in the laminates. The influence of coupling decreased from a large effect in the general unsymmetric laminate, to practically no effect in the quasi-isotropic laminate. For example, the torsional loading of the general unsymmetric laminate resulted in a radial displacement. The temperature change also caused a significant radial displacement to occur near the ends of the cylinder. On the other hand, the more conventional unsymmetric laminate and the quasi-isotropic cylinder did not deform radially when subjected to a torsional load. From the results obtained, it is clear the degree of elastic coupling can be controlled and indeed designed into a cylinder, the degree and character of the coupling being dictated by the application.

Development of Advanced In-Cylinder Components and Tribological Systems for Low Heat Rejection Diesel Engines

NASA Technical Reports Server (NTRS)

Yonushonis, T. M.; Wiczynski, P. D.; Myers, M. R.; Anderson, D. D.; McDonald, A. C.; Weber, H. G.; Richardson, D. E.; Stafford, R. J.; Naylor, M. G.

1999-01-01

In-cylinder components and tribological system concepts were designed, fabricated and tested at conditions anticipated for a 55% thermal efficiency heavy duty diesel engine for the year 2000 and beyond. A Cummins L10 single cylinder research engine was used to evaluate a spherical joint piston and connecting rod with 19.3 MPa (2800 psi) peak cylinder pressure capability, a thermal fatigue resistant insulated cylinder head, radial combustion seal cylinder liners, a highly compliant steel top compression ring, a variable geometry turbocharger, and a microwave heated particulate trap. Components successfully demonstrated in the final test included spherical joint connecting rod with a fiber reinforced piston, high conformability steel top rings with wear resistant coatings, ceramic exhaust ports with strategic oil cooling and radial combustion seal cylinder liner with cooling jacket transfer fins. A Cummins 6B diesel was used to develop the analytical methods, materials, manufacturing technology and engine components for lighter weight diesel engines without sacrificing performance or durability. A 6B diesel engine was built and tested to calibrate analytical models for the aluminum cylinder head and aluminum block.

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.

Multiple Cylinder Free-Piston Stirling Machinery

NASA Astrophysics Data System (ADS)

Berchowitz, David M.; Kwon, Yong-Rak

In order to improve the specific power of piston-cylinder type machinery, there is a point in capacity or power where an advantage accrues with increasing number of piston-cylinder assemblies. In the case of Stirling machinery where primary energy is transferred across the casing wall of the machine, this consideration is even more important. This is due primarily to the difference in scaling of basic power and the required heat transfer. Heat transfer is found to be progressively limited as the size of the machine increases. Multiple cylinder machines tend to preserve the surface area to volume ratio at more favorable levels. In addition, the spring effect of the working gas in the so-called alpha configuration is often sufficient to provide a high frequency resonance point that improves the specific power. There are a number of possible multiple cylinder configurations. The simplest is an opposed pair of piston-displacer machines (beta configuration). A three-cylinder machine requires stepped pistons to obtain proper volume phase relationships. Four to six cylinder configurations are also possible. A small demonstrator inline four cylinder alpha machine has been built to demonstrate both cooling operation and power generation. Data from this machine verifies theoretical expectations and is used to extrapolate the performance of future machines. Vibration levels are discussed and it is argued that some multiple cylinder machines have no linear component to the casing vibration but may have a nutating couple. Example applications are discussed ranging from general purpose coolers, computer cooling, exhaust heat power extraction and some high power engines.

Natural convective heat transfer from square cylinder

DOE Office of Scientific and Technical Information (OSTI.GOV)

Novomestský, Marcel, E-mail: marcel.novomestsky@fstroj.uniza.sk; Smatanová, Helena, E-mail: helena.smatanova@fstroj.uniza.sk; Kapjor, Andrej, E-mail: andrej.kapjor@fstroj.uniza.sk

This article is concerned with natural convective heat transfer from square cylinder mounted on a plane adiabatic base, the cylinders having an exposed cylinder surface according to different horizontal angle. The cylinder receives heat from a radiating heater which results in a buoyant flow. There are many industrial applications, including refrigeration, ventilation and the cooling of electrical components, for which the present study may be applicable.

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…

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.

Equivalence of expressions for the radiation force on cylinders and application to elliptical cylinders

NASA Astrophysics Data System (ADS)

Wei, Wei; Marston, Philip L.

2005-09-01

Using an appropriate grouping of terms, a radiation force expression for cylinders in a standing wave based on far-field scattering [W. Wei, D. B. Thiessen, and P. L. Marston, J. Acoust. Soc. Am. 116, 202-208 (2004)] is transformed to an expression given elsewhere [F. G. Mitri, Eur. Phys. J. B 44, 71-78 (2005)]. Mitri's result is from a near-field derivation for the specific case of a circular cylinder. In the usual case, in an ideal lossless media the far-field derivation is not an approximation. The far-field derivation also applies to noncircular objects having mirror symmetry about the incident wave vector. Some general and historical aspects of far-field derivations of optical and acoustical radiation force (going back to 1909) will be noted. Our formulation yields a simple low-frequency approximation for the radiation force on elliptical cylinders by introducing approximations for the partial-wave scattering coefficients of elliptical cylinders first derived by Rayleigh. [Work supported by NASA.

Free Surface Wave Interaction with a Horizontal Cylinder

NASA Astrophysics Data System (ADS)

Oshkai, P.; Rockwell, D.

1999-10-01

Classes of vortex formation from a horizontal cylinder adjacent to an undulating free-surface wave are characterized using high-image-density particle image velocimetry. Instantaneous representations of the velocity field, streamline topology and vorticity patterns yield insight into the origin of unsteady loading of the cylinder. For sufficiently deep submergence of the cylinder, the orbital nature of the wave motion results in multiple sites of vortex development, i.e., onset of vorticity concentrations, along the surface of the cylinder, followed by distinctive types of shedding from the cylinder. All of these concentrations of vorticity then exhibit orbital motion about the cylinder. Their contributions to the instantaneous values of the force coefficients are assessed by calculating moments of vorticity. It is shown that large contributions to the moments and their rate of change with time can occur for those vorticity concentrations having relatively small amplitude orbital trajectories. In a limiting case, collision with the surface of the cylinder can occur. Such vortex-cylinder interactions exhibit abrupt changes in the streamline topology during the wave cycle, including abrupt switching of the location of saddle points in the wave. The effect of nominal depth of submergence of the cylinder is characterized in terms of the time history of patterns of vorticity generated from the cylinder and the free surface. Generally speaking, generic types of vorticity concentrations are formed from the cylinder during the cycle of the wave motion for all values of submergence. The proximity of the free surface, however, can exert a remarkable influence on the initial formation, the eventual strength, and the subsequent motion of concentrations of vorticity. For sufficiently shallow submergence, large-scale vortex formation from the upper surface of the cylinder is inhibited and, in contrast, that from the lower surface of the cylinder is intensified. Moreover

Five-cylinder engine as an economical, smooth-running power plant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hauk, F.; Dommes, W.

For the first time in the history of automobile engineering, AUDI NSU has introduced a 5-cylinder in-line gasoline engine for production cars designed to run at speeds up to about 7,000 rpm. This unusual new design makes it possible to set new standards of performance and smoothness, while still retaining the advantages of front wheel drive.

Single-Cylinder Oil-Control Tests of Porous Chrome-Plated Cylinder Barrels for Radial Air-Cooled Engines

DTIC Science & Technology

1946-01-01

plating, it will affect a choke as desired in the cylinder. When the clearance between the anode and the cathode (cylinder barrel) is decreased, an...National Advisory Commltteo for Aeronautics, Cltivel« oid , Ohio. RSFEFKICE3 1. Johnson, Robert L., wad Anderson, Roy I.: S.’.nglo-Cylindor Engine Tests...plating a choke in the bore. Choice la obtained by decreasing the clear- ance between the anode and the cylinder barrel ( cathode ). Taper on anode la

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.

A low-background piston-cylinder-type hybrid high pressure cell for muon-spin rotation/relaxation experiments

NASA Astrophysics Data System (ADS)

Shermadini, Z.; Khasanov, R.; Elender, M.; Simutis, G.; Guguchia, Z.; Kamenev, K. V.; Amato, A.

2017-10-01

A low background double-wall piston-cylinder-type pressure cell is developed at the Paul Scherrer Institute. The cell is made from BERYLCO-25 (beryllium copper) and MP35N nonmagnetic alloys with the design and dimensions which are specifically adapted to muon-spin rotation/relaxation (μSR) measurements. The mechanical design and performance of the pressure cell are evaluated using finite-element analysis (FEA). By including the measured stress-strain characteristics of the materials into the finite-element model, the cell dimensions are optimized with the aim to reach the highest possible pressure while maintaining the sample space large (6 mm in diameter and 12 mm high). The presented unconventional design of the double-wall piston-cylinder pressure cell with a harder outer MP35N sleeve and a softer inner CuBe cylinder enables pressures of up to 2.6 GPa to be reached at ambient temperature, corresponding to 2.2 GPa at low temperatures without any irreversible damage to the pressure cell. The nature of the muon stopping distribution, mainly in the sample and in the CuBe cylinder, results in a low-background μSR signal.

PIV measurements of in-cylinder, large-scale structures in a water-analogue Diesel engine

NASA Astrophysics Data System (ADS)

Kalpakli Vester, A.; Nishio, Y.; Alfredsson, P. H.

2016-11-01

Swirl and tumble are large-scale structures that develop in an engine cylinder during the intake stroke. Their structure and strength depend on the design of the inlet ports and valves, but also on the valve lift history. Engine manufacturers make their design to obtain a specific flow structure that is assumed to give the best engine performance. Despite many efforts, there are still open questions, such as how swirl and tumble depend on the dynamics of the valves/piston as well as how cycle-to-cycle variations should be minimized. In collaboration with Swedish vehicle industry we perform PIV measurements of the flow dynamics during the intake stroke inside a cylinder of a water-analogue engine model having the same geometrical characteristics as a typical truck Diesel engine. Water can be used since during the intake stroke the flow is nearly incompressible. The flow from the valves moves radially outwards, hits the vertical walls of the cylinder, entrains surrounding fluid, moves along the cylinder walls and creates a central backflow, i.e. a tumble motion. Depending on the port and valve design and orientation none, low, or high swirl can be established. For the first time, the effect of the dynamic motion of the piston/valves on the large-scale structures is captured. Supported by the Swedish Energy Agency, Scania CV AB and Volvo GTT, through the FFI program.

An Approximate Solution and Master Curves for Buckling of Symmetrically Laminated Composite Cylinders

NASA Technical Reports Server (NTRS)

Nemeth, Michael P.

2013-01-01

Nondimensional linear-bifurcation buckling equations for balanced, symmetrically laminated cylinders with negligible shell-wall anisotropies and subjected to uniform axial compression loads are presented. These equations are solved exactly for the practical case of simply supported ends. Nondimensional quantities are used to characterize the buckling behavior that consist of a stiffness-weighted length-to-radius parameter, a stiffness-weighted shell-thinness parameter, a shell-wall nonhomogeneity parameter, two orthotropy parameters, and a nondimensional buckling load. Ranges for the nondimensional parameters are established that encompass a wide range of laminated-wall constructions and numerous generic plots of nondimensional buckling load versus a stiffness-weighted length-to-radius ratio are presented for various combinations of the other parameters. These plots are expected to include many practical cases of interest to designers. Additionally, these plots show how the parameter values affect the distribution and size of the festoons forming each response curve and how they affect the attenuation of each response curve to the corresponding solution for an infinitely long cylinder. To aid in preliminary design studies, approximate formulas for the nondimensional buckling load are derived, and validated against the corresponding exact solution, that give the attenuated buckling response of an infinitely long cylinder in terms of the nondimensional parameters presented herein. A relatively small number of "master curves" are identified that give a nondimensional measure of the buckling load of an infinitely long cylinder as a function of the orthotropy and wall inhomogeneity parameters. These curves reduce greatly the complexity of the design-variable space as compared to representations that use dimensional quantities as design variables. As a result of their inherent simplicity, these master curves are anticipated to be useful in the ongoing development of

Cylinder head for internal combustion engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bell, D.W.

1992-10-06

This patent describes a cylinder head for attachment to a block assembly having at least one cylinder bore therein. It comprises: a cylinder head body adapted for attachment to the block assembly and having at least one side-entry fluid intake opening in communication with the cylinder bore, and having at least one side-exit exhaust fluid opening in communication with the cylinderbore; an intake spool mounted for axial rotation within the intake spool cavity; an exhaust spool mounted for axial rotation within the exhaust spool cavity; timing means for rotating the intake spool and the exhaust spool; and at least onemore » intake port and at least one exhaust port.« less

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 shall...

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 shall...

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 shall...

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 shall...

Cylinder valve packing nut studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

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.

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.

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 be...

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 be...

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 be...

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 be...

High resolution remanent magnetization scanner for long cores

NASA Astrophysics Data System (ADS)

Demory, François; Quesnel, Yoann; Uehara, Minoru; Rochette, Pierre; Zylberman, William; Romey, Carole; Pignol, Laure; Andrieu-Ponel, Valérie

2017-04-01

Superconducting rock magnetometer reaches saturation when measuring magnetic moments higher than 5 10-5 Am2. Due to the distance of the sensor from the measurement zone, the spatial resolution is low for continuous measurements led on U channel or cores. To solve these problems, we designed a core logger dedicated to the measurement of remanent magnetizations. Based on a fluxgate sensor located very close to the sample, the spatial resolution of the core logger is infra-centimetric. The fluxgate sensor is also able to detect magnetic fields of few nT produced by magnetic moments of the order of few 10-8 Am2. As the equipment does not reach saturation, we measured isothermal remanent magnetization of highly magnetic samples. This magnetization was acquired perpendicularly to the long axis of U-channels from Cassis paleo-lake (Romey et al., 2015) and of cores from Haughton impact structure (Zylberman et al., submitted) using Halbach cylinders (Rochette et al., 2001). To interpret local magnetic fields in terms of magnetic moments, we performed an inter-calibration with the superconducting rock magnetometer and signal inversion. This development led to the filing of a patent (FR.16/53142) and is funded by the ECCOREV project MESENVIMAG. References: Rochette, P., Vadeboin, F., Clochard, L., 2001. Rock magnetic applications of Halbach cylinders. Physics of the Earth and Planetary Interiors 126, 109-117. Romey, C., Vella, C., Rochette, P., Andrieu-Ponel, V., Magnin, F., Veron, A., Talon, B., Landure, C., D'Ovidio, A.M., Delanghe, D., Ghilardi, M., Angeletti, B., 2015. Environmental imprints of landscape evolution and human activities during the Holocene in a small catchment of the Calanques Massif (Cassis, southern France). Holocene 25 (9), 1454-1469. Zylberman W., Quesnel Y., Rochette P., Osinski G. R., Marion C., Gattacceca J. (submitted to MAPS) Hydrothermally-enhanced magnetization at the center of the Haughton impact structure? (Nunavut, Canada).

46 CFR 197.338 - Compressed gas cylinders.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 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; (c... 46 Shipping 7 2010-10-01 2010-10-01 false Compressed gas cylinders. 197.338 Section 197.338...

Experimental investigation of thermal processes in the multi-ring Couette system with counter rotation of cylinders

NASA Astrophysics Data System (ADS)

Mamonov, V. N.; Nazarov, A. D.; Serov, A. F.; Terekhov, V. I.

2016-01-01

The effect of parameters of the multi-ring Couette system with counter rotating coaxial cylinders on the process of thermal energy release in a viscous liquid filling this system is considered with regard to the problem of determining the possibility of creating the high-performance wind heat generator. The multi-cylinder rotor design allows directly conversion of the mechanical power of a device consisting of two "rotor" wind turbines with a common axis normal to the air flow into the thermal energy in a wide range of rotational speed of the cylinders. Experimental results on the measurement of thermal power released in the pilot heat generator at different relative angular speeds of cylinder rotation are presented.

CORSSTOL: Cylinder Optimization of Rings, Skin, and Stringers with Tolerance sensitivity

NASA Technical Reports Server (NTRS)

Finckenor, J.; Bevill, M.

1995-01-01

Cylinder Optimization of Rings, Skin, and Stringers with Tolerance (CORSSTOL) sensitivity is a design optimization program incorporating a method to examine the effects of user-provided manufacturing tolerances on weight and failure. CORSSTOL gives designers a tool to determine tolerances based on need. This is a decisive way to choose the best design among several manufacturing methods with differing capabilities and costs. CORSSTOL initially optimizes a stringer-stiffened cylinder for weight without tolerances. The skin and stringer geometry are varied, subject to stress and buckling constraints. Then the same analysis and optimization routines are used to minimize the maximum material condition weight subject to the least favorable combination of tolerances. The adjusted optimum dimensions are provided with the weight and constraint sensitivities of each design variable. The designer can immediately identify critical tolerances. The safety of parts made out of tolerance can also be determined. During design and development of weight-critical systems, design/analysis tools that provide product-oriented results are of vital significance. The development of this program and methodology provides designers with an effective cost- and weight-saving design tool. The tolerance sensitivity method can be applied to any system defined by a set of deterministic equations.

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.

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.

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.

Suppression of vortex-induced vibrations in a flexible cylinder with elastic splitter plates

NASA Astrophysics Data System (ADS)

Huera-Huarte, Francisco

2013-11-01

Suppression of vortex-induced vibrations (VIV) is a topic that has received a lot of attention due to its practical implications in engineering design. Experiments have been conducted in a recirculating free surface water channel, with a working section of dimensions 1 × 1.1 × 2.5 m. A cylinder model made of a spring and a plastic cover was used for the experiments. It was placed horizontally and fully submerged in the water channel's free stream, hanging from two submersible load cells arranged to measure the total drag force on the cylinder. The model had several white points painted on its surface, so its VIV motion was obtained by imaging it with two cameras synchronised with a strobe light. Image processing allowed to obtain the displacements along the length of the cylinder with sub-pixel accuracy. Digital Particle Image Velocimetry (DPIV) was also used to quantify the wake downstream the cylinder. A full set of experiments was made for reference purposes with a plain cylinder without suppressors, and for the same conditions, several passive suppression devices such as elastic splitter plates of different sizes and shapes, were installed on the cylinder. Passive VIV suppression with drag reduction was achieved with some of the configurations tested. Funding provided by the Spanish Ministry of Science through grant DPI2012-37904 is acknowledged.

Scavenging a Piston-ported Two-stroke Cylinder

NASA Technical Reports Server (NTRS)

Rogowski, A R; Bouchard, C L

1938-01-01

An investigation was made with a specially designed engine to determine the scavenging characteristics of a large number of inlet-port shapes and arrangements and the optimum port arrangement and timing for this particular type of engine. A special cylinder construction permitted wide variations in timing for this particular type of engine. A special cylinder construction permitted wide variations in timing as well as in shape and arrangement of both the inlet and exhaust ports. The study of the effect of port shape combinations and timings on engine performance was made using illuminating gas as a fuel. Through variations in inlet-port arrangement and port timings, the value of the scavenging efficiency was increased from an original 44 percent to approximately 67 percent with a corresponding increase in power. With the optimum port arrangement and timing determined, a large number of performance runs were made under both spark-ignition and compression-ignition operation.

Influence of magnetization on the applied magnetic field in various AMR regenerators

NASA Astrophysics Data System (ADS)

Mira, A.; de Larochelambert, T.; Espanet, C.; Giurgea, S.; Nika, P.; Bahl, C. R. H.; Bjørk, R.; Nielsen, K. K.

2017-10-01

The aim of this work is to assess the influence of a magnetic sample on the applied magnetic field inside the air gap of a magnetic circuit. Different magnetic sources including an electromagnet, a permanent magnet in a soft ferromagnetic toroidal yoke, as well as 2D and 3D Halbach cylinders are considered, using a numerical model. Gadolinium is chosen as magnetic material for the sample, due to its strong magnetocaloric properties and its wide use in magnetic refrigeration prototypes. We find that using uniform theoretical demagnetizing factors for cylinders or spheres results in a deviation of less than 2% in the calculation of internal magnetic fields at temperatures above the Curie point of gadolinium. Below the Curie point, a stronger magnetization of the cylinders and spheres leads to a larger deviation which can reach 8% when using uniform demagnetizing factors for internal magnetic field calculations.

Implementation of Fiber Optic Sensing System on Sandwich Composite Cylinder Buckling Test

NASA Technical Reports Server (NTRS)

Pena, Francisco; Richards, W. Lance; Parker, Allen R.; Piazza, Anthony; Schultz, Marc R.; Rudd, Michelle T.; Gardner, Nathaniel W.; Hilburger, Mark W.

2018-01-01

The National Aeronautics and Space Administration (NASA) Engineering and Safety Center Shell Buckling Knockdown Factor Project is a multicenter project tasked with developing new analysis-based shell buckling design guidelines and design factors (i.e., knockdown factors) through high-fidelity buckling simulations and advanced test technologies. To validate these new buckling knockdown factors for future launch vehicles, the Shell Buckling Knockdown Factor Project is carrying out structural testing on a series of large-scale metallic and composite cylindrical shells at the NASA Marshall Space Flight Center (Marshall Space Flight Center, Alabama). A fiber optic sensor system was used to measure strain on a large-scale sandwich composite cylinder that was tested under multiple axial compressive loads up to more than 850,000 lb, and equivalent bending loads over 22 million in-lb. During the structural testing of the composite cylinder, strain data were collected from optical cables containing distributed fiber Bragg gratings using a custom fiber optic sensor system interrogator developed at the NASA Armstrong Flight Research Center. A total of 16 fiber-optic strands, each containing nearly 1,000 fiber Bragg gratings, measuring strain, were installed on the inner and outer cylinder surfaces to monitor the test article global structural response through high-density real-time and post test strain measurements. The distributed sensing system provided evidence of local epoxy failure at the attachment-ring-to-barrel interface that would not have been detected with conventional instrumentation. Results from the fiber optic sensor system were used to further refine and validate structural models for buckling of the large-scale composite structures. This paper discusses the techniques employed for real-time structural monitoring of the composite cylinder for structural load introduction and distributed bending-strain measurements over a large section of the cylinder by

On propagation of axisymmetric waves in pressurized functionally graded elastomeric hollow cylinders

NASA Astrophysics Data System (ADS)

Wu, Bin; Su, Yipin; Liu, Dongying; Chen, Weiqiu; Zhang, Chuanzeng

2018-05-01

Soft materials can be designed with a functionally graded (FG) property for specific applications. Such material inhomogeneity can also be found in many soft biological tissues whose functionality is only partly understood to date. In this paper, we analyze the axisymmetric guided wave propagation in a pressurized FG elastomeric hollow cylinder. The cylinder is subjected to a combined action of axial pre-stretch and pressure difference applied to the inner and outer cylindrical surfaces. We consider both torsional waves and longitudinal waves propagating in the FG cylinder made of incompressible isotropic elastomer, which is characterized by the Mooney-Rivlin strain energy function but with the material parameters varying with the radial coordinate in an affine way. The pressure difference generates an inhomogeneous deformation field in the FG cylinder, which dramatically complicates the superimposed wave problem described by the small-on-large theory. A particularly efficient approach is hence employed which combines the state-space formalism for the incremental wave motion with the approximate laminate or multi-layer technique. Dispersion relations for the two types of axisymmetric guided waves are then derived analytically. The accuracy and convergence of the proposed approach is validated numerically. The effects of the pressure difference, material gradient, and axial pre-stretch on both the torsional and the longitudinal wave propagation characteristics are discussed in detail through numerical examples. It is found that the frequency of axisymmetric waves depends nonlinearly on the pressure difference and the material gradient, and an increase in the material gradient enhances the capability of the pressure difference to adjust the wave behavior in the FG cylinder. This work provides a theoretical guidance for characterizing FG soft materials by in-situ ultrasonic nondestructive evaluation and for designing tunable waveguides via material tailoring along

Dragging a floating horizontal cylinder

NASA Astrophysics Data System (ADS)

Lee, Duck-Gyu; Kim, Ho-Young

2010-11-01

A cylinder immersed in a fluid stream experiences a drag, and it is well known that the drag coefficient is a function of the Reynolds number only. Here we study the force exerted on a long horizontal cylinder that is dragged perpendicular to its axis while floating on an air-water interface with a high Reynolds number. In addition to the flow-induced drag, the floating body is subjected to capillary forces along the contact line where the three phases of liquid/solid/gas meet. We first theoretically predict the meniscus profile around the horizontally moving cylinder assuming the potential flow, and show that the profile is in good agreement with that obtained experimentally. Then we compare our theoretical predictions and experimental measurement results for the drag coefficient of a floating horizontal cylinder that is given by a function of the Weber number and the Bond number. This study can help us to understand the horizontal motion of partially submerged objects at air-liquid interface, such as semi-aquatic insects and marine plants.

Cylinder surface test with Chebyshev polynomial fitting method

NASA Astrophysics Data System (ADS)

Yu, Kui-bang; Guo, Pei-ji; Chen, Xi

2017-10-01

Zernike polynomials fitting method is often applied in the test of optical components and systems, used to represent the wavefront and surface error in circular domain. Zernike polynomials are not orthogonal in rectangular region which results in its unsuitable for the test of optical element with rectangular aperture such as cylinder surface. Applying the Chebyshev polynomials which are orthogonal among the rectangular area as an substitution to the fitting method, can solve the problem. Corresponding to a cylinder surface with diameter of 50 mm and F number of 1/7, a measuring system has been designed in Zemax based on Fizeau Interferometry. The expressions of the two-dimensional Chebyshev polynomials has been given and its relationship with the aberration has been presented. Furthermore, Chebyshev polynomials are used as base items to analyze the rectangular aperture test data. The coefficient of different items are obtained from the test data through the method of least squares. Comparing the Chebyshev spectrum in different misalignment, it show that each misalignment is independence and has a certain relationship with the certain Chebyshev terms. The simulation results show that, through the Legendre polynomials fitting method, it will be a great improvement in the efficient of the detection and adjustment of the cylinder surface test.

An investigation of crankshaft oscillations for cylinder health diagnostics

NASA Astrophysics Data System (ADS)

Geveci, Mert; Osburn, Andrew W.; Franchek, Matthew A.

2005-09-01

The vibrational characteristics of an internal combustion engine crankshaft are investigated from a cylinder health diagnostics point of view. Experimental results from a six-cylinder industrial diesel engine are presented to demonstrate the effects of cylinder imbalance on the individual harmonic components of the engine speed signal. A crank-angle domain numerical model of the crankshaft dynamics for a six-cylinder industrial diesel engine is also adopted to establish the effects of continuous low-power production in individual cylinders of a multi-cylinder engine. Outline of a diagnostics algorithm that makes use of the properties of crankshaft vibration behaviour is provided. In particular, crank-angle domain notch filters are employed to extact the harmonic components of engine speed. The outlined method can be implemented for individual cylinder health diagnostics across a family of multi-cylinder engines and can be formulated to handle changes in crankshaft characteristics due to replacement of mechanical components and/or wear.

49 CFR 178.68 - Specification 4E welded aluminum cylinders.

Code of Federal Regulations, 2012 CFR

2012-10-01

... to cylinder by welding by inert gas shielded arc process or by threads. If threads are used, they... process and cylinders with longitudinal seams are not authorized. (b) Authorized material. The cylinder...'s lot number. (d) Manufacture. Cylinders must be manufactured using equipment and processes adequate...

49 CFR 178.68 - Specification 4E welded aluminum cylinders.

Code of Federal Regulations, 2014 CFR

2014-10-01

... to cylinder by welding by inert gas shielded arc process or by threads. If threads are used, they... process and cylinders with longitudinal seams are not authorized. (b) Authorized material. The cylinder...'s lot number. (d) Manufacture. Cylinders must be manufactured using equipment and processes adequate...

49 CFR 178.68 - Specification 4E welded aluminum cylinders.

Code of Federal Regulations, 2013 CFR

2013-10-01

... to cylinder by welding by inert gas shielded arc process or by threads. If threads are used, they... process and cylinders with longitudinal seams are not authorized. (b) Authorized material. The cylinder...'s lot number. (d) Manufacture. Cylinders must be manufactured using equipment and processes adequate...

Flow past a rotating cylinder

NASA Astrophysics Data System (ADS)

Mittal, Sanjay; Kumar, Bhaskar

2003-02-01

Flow past a spinning circular cylinder placed in a uniform stream is investigated via two-dimensional computations. A stabilized finite element method is utilized to solve the incompressible Navier Stokes equations in the primitive variables formulation. The Reynolds number based on the cylinder diameter and free-stream speed of the flow is 200. The non-dimensional rotation rate, [alpha] (ratio of the surface speed and freestream speed), is varied between 0 and 5. The time integration of the flow equations is carried out for very large dimensionless time. Vortex shedding is observed for [alpha] < 1.91. For higher rotation rates the flow achieves a steady state except for 4.34 < [alpha] < 4:70 where the flow is unstable again. In the second region of instability, only one-sided vortex shedding takes place. To ascertain the instability of flow as a function of [alpha] a stabilized finite element formulation is proposed to carry out a global, non-parallel stability analysis of the two-dimensional steady-state flow for small disturbances. The formulation and its implementation are validated by predicting the Hopf bifurcation for flow past a non-rotating cylinder. The results from the stability analysis for the rotating cylinder are in very good agreement with those from direct numerical simulations. For large rotation rates, very large lift coefficients can be obtained via the Magnus effect. However, the power requirement for rotating the cylinder increases rapidly with rotation rate.

Optimized Dose Distribution of Gammamed Plus Vaginal Cylinders

DOE Office of Scientific and Technical Information (OSTI.GOV)

Supe, Sanjay S.; Bijina, T.K.; Varatharaj, C.

2009-04-01

Endometrial carcinoma is the most common malignancy arising in the female genital tract. Intracavitary vaginal cuff irradiation may be given alone or with external beam irradiation in patients determined to be at risk for locoregional recurrence. Vaginal cylinders are often used to deliver a brachytherapy dose to the vaginal apex and upper vagina or the entire vaginal surface in the management of postoperative endometrial cancer or cervical cancer. The dose distributions of HDR vaginal cylinders must be evaluated carefully, so that clinical experiences with LDR techniques can be used in guiding optimal use of HDR techniques. The aim of thismore » study was to optimize dose distribution for Gammamed plus vaginal cylinders. Placement of dose optimization points was evaluated for its effect on optimized dose distributions. Two different dose optimization point models were used in this study, namely non-apex (dose optimization points only on periphery of cylinder) and apex (dose optimization points on periphery and along the curvature including the apex points). Thirteen dwell positions were used for the HDR dosimetry to obtain a 6-cm active length. Thus 13 optimization points were available at the periphery of the cylinder. The coordinates of the points along the curvature depended on the cylinder diameters and were chosen for each cylinder so that four points were distributed evenly in the curvature portion of the cylinder. Diameter of vaginal cylinders varied from 2.0 to 4.0 cm. Iterative optimization routine was utilized for all optimizations. The effects of various optimization routines (iterative, geometric, equal times) was studied for the 3.0-cm diameter vaginal cylinder. The effect of source travel step size on the optimized dose distributions for vaginal cylinders was also evaluated. All optimizations in this study were carried for dose of 6 Gy at dose optimization points. For both non-apex and apex models of vaginal cylinders, doses for apex point and

A Visual Photographic Study of Cylinder Lubrication

NASA Technical Reports Server (NTRS)

Shaw, Milton C; Nussdorfer, Theodore

1946-01-01

A V-type engine provided with a glass cylinder was used to study visually the lubrication characteristics of an aircraft-type piston. Photographs and data were obtained with the engine motored at engine speeds up to 1000 r.p.m. and constant cylinder-head pressures of 0 and 50 pounds per square inch. A study was made of the orientation of the piston under various operating conditions, which indicated that the piston was inclined with the crown nearest the major-thrust cylinder face throughout the greater part of the cycle. The piston moved laterally in the cylinder under the influence of piston side thrust.

Development of control system of coating of rod hydraulic cylinders

NASA Astrophysics Data System (ADS)

Aizhambaeva, S. Zh; Maximova, A. V.

2018-01-01

In this article, requirements to materials of hydraulic cylinders and methods of eliminating the main factors affecting the quality of the applied coatings rod hydraulic cylinders. The chromium plating process - one of ways of increase of anti-friction properties of coatings rods, stability to the wear and corrosion. The article gives description of differences of the stand-speed chromium plating process from other types of chromium plating that determines a conclusion about cutting time of chromium plating process. Conducting the analysis of technological equipment suggested addressing the modernization of high-speed chromium plating processes by automation and mechanization. Control system developed by design of schematic block diagram of a modernized and stand-speed chromium plating process.

Investigating adsorption/desorption of carbon dioxide in aluminum compressed gas cylinders.

PubMed

Miller, Walter R; Rhoderick, George C; Guenther, Franklin R

2015-02-03

Between June 2010 and June 2011, the National Institute of Standards and Technology (NIST) gravimetrically prepared a suite of 20 carbon dioxide (CO2) in air primary standard mixtures (PSMs). Ambient mole fraction levels were obtained through six levels of dilution beginning with pure (99.999%) CO2. The sixth level covered the ambient range from 355 to 404 μmol/mol. This level will be used to certify cylinder mixtures of compressed dry whole air from both the northern and southern hemispheres as NIST standard reference materials (SRMs). The first five levels of PSMs were verified against existing PSMs in a balance of air or nitrogen with excellent agreement observed (the average percent difference between the calculated and analyzed values was 0.002%). After the preparation of a new suite of PSMs at ambient level, they were compared to an existing suite of PSMs. It was observed that the analyzed concentration of the new PSMs was less than the calculated gravimetric concentration by as much as 0.3% relative. The existing PSMs had been used in a Consultative Committee for Amount of Substance-Metrology in Chemistry Key Comparison (K-52) in which there was excellent agreement (the NIST-analyzed value was -0.09% different from the calculated value, while the average of the difference for all 18 participants was -0.10%) with those of other National Metrology Institutes and World Meteorological Organization designated laboratories. In order to determine the magnitude of these losses at the ambient level, a series of "daughter/mother" tests were initiated and conducted in which the gas mixture containing CO2 from a "mother" cylinder was transferred into an evacuated "daughter" cylinder. These cylinder pairs were then compared using cavity ring-down spectroscopy under high reproducibility conditions (the average percent relative standard deviation of sample response was 0.02). A ratio of the daughter instrument response to the mother response was calculated, with the

CNG Cylinder Safety - Education, Outreach, and Next Steps (Presentation)

DOE Office of Scientific and Technical Information (OSTI.GOV)

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 frommore » 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.« less

Cell cloning-on-the-spot by using an attachable silicone cylinder.

PubMed

Park, Hong Bum; Son, Wonseok; Chae, Dong Han; Lee, Jisu; Kim, Il-Woung; Yang, Woomi; Sung, Jae Kyu; Lim, Kyu; Lee, Jun Hee; Kim, Kyung-Hee; Park, Jong-Il

2016-06-10

Cell cloning is a laboratory routine to isolate and keep particular properties of cultured cells. Transfected or other genetically modified cells can be selected by the traditional microbiological cloning. In addition, common laboratory cell lines are prone to genotypic drift during their continual culture, so that supplementary cloning steps are often required to maintain correct lineage phenotypes. Here, we designed a silicone-made attachable cloning cylinder, which facilitated an easy and bona fide cloning of interested cells. This silicone cylinder was easy to make, showed competent stickiness to laboratory plastics including culture dishes, and hence enabled secure isolation and culture for days of selected single cells, especially, on the spots of preceding cell-plating dishes under microscopic examination of visible cellular phenotypes. We tested the silicone cylinder in the monoclonal subcloning from a heterogeneous population of a breast cancer cell line, MDA-MB-231, and readily established independent MDA-MB-231 subclones showing different sublineage phenotypes. Copyright © 2016 Elsevier Inc. All rights reserved.

Viscous free-surface flows on rotating elliptical cylinders

NASA Astrophysics Data System (ADS)

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

2017-09-01

The flow of liquid films on rotating discrete objects having complicated cross sections is encountered in coating processes for a broad variety of products. To advance fundamental understanding of this problem, we study viscous free-surface flows on rotating elliptical cylinders by solving the governing equations in a rotating reference frame using the Galerkin finite-element method. Results of our simulations agree well with Hunt's maximum-load condition [Hunt, Numer. Methods Partial Differ. Eqs. 24, 1094 (2008), 10.1002/num.20307], which was obtained in the absence of surface tension and inertia. The simulations are also used to track the transient behavior of the free surface. For O (1 ) cylinder aspect ratios, cylinder rotation results in a droplike liquid bulge hanging on the upward-moving side of the cylinder. This bulge shrinks in size due to surface tension provided that the liquid load is smaller than a critical value, leaving a relatively smooth coating on the cylinder. A decrease in cylinder aspect ratio leads to larger gradients in film thickness, but enhances the rate of bulge shrinkage and thus shortens the time required to obtain a smooth coating. Moreover, with a suitably chosen time-dependent rotation rate, more liquid can be supported by the cylinder relative to the constant-rotation-rate case. For cylinders with even smaller aspect ratios, film rupture and liquid shedding may occur over the cylinder tips, so simultaneous drying and rotation along with the introduction of Marangoni stresses will likely be especially important for obtaining a smooth coating.

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.

Magnetic field mapping of the UCNTau magneto-gravitational trap: design study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Libersky, Matthew Murray

2014-09-04

The beta decay lifetime of the free neutron is an important input to the Standard Model of particle physics, but values measured using different methods have exhibited substantial disagreement. The UCN r experiment in development at Los Alamos National Laboratory (LANL) plans to explore better methods of measuring the neutron lifetime using ultracold neutrons (UCNs). In this experiment, UCNs are confined in a magneto-gravitational trap formed by a curved, asymmetric Halbach array placed inside a vacuum vessel and surrounded by holding field coils. If any defects present in the Halbach array are sufficient to reduce the local field near themore » surface below that needed to repel the desired energy level UCNs, loss by material interaction can occur at a rate similar to the loss by beta decay. A map of the magnetic field near the surface of the array is necessary to identify any such defects, but the array's curved geometry and placement in a vacuum vessel make conventional field mapping methods difficult. A system consisting of computer vision-based tracking and a rover holding a Hall probe has been designed to map the field near the surface of the array, and construction of an initial prototype has begun at LANL. The design of the system and initial results will be described here.« less

Using the adaptive SMA composite cylinder concept to reduce radial dilation in composite pressure vessels

NASA Astrophysics Data System (ADS)

Paine, Jeffrey S.; Rogers, Craig A.

1995-05-01

Composite materials are widely used in the design of pressurized gas and fluid vessels for applications ranging from underground gasoline storage tanks to rocket motors for the space shuttle. In the design of a high pressure composite vessel (Pi > 12 Ksi), thick-wall (R/h < 15) vessels are required. For efficient material use in composite material vessels, the radial dilation (expansion or swelling) of the composite vessel can often approach values nearing 2 percent of the diameter. Over long periods of internal pressure loading over elevated temperatures, composite material cylinders may also experience substantial creep. The short term dilation and long term creep are not problematic for applications requiring only the containment of the pressurized fluid. In applications where metallic liners are required, however, substantial dilation and creep causes plastic yielding which leads to reduced fatigue life. To applications such as a hydraulic accumulator, where a piston is employed to fit and seal the fluid in the composite cylinder, the dilation and creep may allow leakage and pressure loss around the piston. A concept called the adaptive composite cylinder is experimentally presented. Shape memory alloy wire in epoxy resin is wrapped around or within polymer matrix composite cylinders to reduce radial dilation of the cylinder. Experimental results are presented that demonstrate the ability of the SMA wire layers to reduce radial dilation. Results from experimental testing of the recovery stress fatigue response of nitinol shape memory alloy wires is also presented.

Charging Characteristics of an Insulating Hollow Cylinder in Vacuum

NASA Astrophysics Data System (ADS)

Yamamoto, Osamu; Hayashi, Hirotaka; Wadahama, Toshihiko; Takeda, Daisuke; Hamada, Shoji; Ohsawa, Yasuharu

This paper deals with charging characteristics of the inner surface of an insulating hollow cylinder in vacuum. We conducted measurements of electric field strength near the triple points on cathode by using an electrostatic probe. Also we conducted a computer simulation of charging based on the Secondary Electron Emission Avalanche (SEEA) mechanism. These results are compared with those obtained previously for solid cylinders. As a result, we have clarified that hollow cylinders acquire surface charge which is larger than that of solid cylinders. We have also found that charge controlling effect by roughening the inner surface, which have been proved effective to depress charging on the surface of solid cylinders in our previous studies, is limited for hollow cylinders.

Theory of interacting dislocations on cylinders.

PubMed

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.

49 CFR 173.316 - Cryogenic liquids in cylinders.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 2 2013-10-01 2013-10-01 false Cryogenic liquids in cylinders. 173.316 Section... REQUIREMENTS FOR SHIPMENTS AND PACKAGINGS Gases; Preparation and Packaging § 173.316 Cryogenic liquids in cylinders. (a) General requirements. (1) A cylinder may not be loaded with a cryogenic liquid colder than...

49 CFR 173.316 - Cryogenic liquids in cylinders.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 2 2014-10-01 2014-10-01 false Cryogenic liquids in cylinders. 173.316 Section... REQUIREMENTS FOR SHIPMENTS AND PACKAGINGS Gases; Preparation and Packaging § 173.316 Cryogenic liquids in cylinders. (a) General requirements. (1) A cylinder may not be loaded with a cryogenic liquid colder than...

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.

49 CFR 176.92 - Cylinders laden in vehicles.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 2 2014-10-01 2014-10-01 false Cylinders laden in vehicles. 176.92 Section 176.92... 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 CFR 176.92 - Cylinders laden in vehicles.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Cylinders laden in vehicles. 176.92 Section 176.92... 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 CFR 176.92 - Cylinders laden in vehicles.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 2 2013-10-01 2013-10-01 false Cylinders laden in vehicles. 176.92 Section 176.92... 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 CFR 176.92 - Cylinders laden in vehicles.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 2 2012-10-01 2012-10-01 false Cylinders laden in vehicles. 176.92 Section 176.92... 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 CFR 178.57 - Specification 4L welded insulated cylinders.

Code of Federal Regulations, 2013 CFR

2013-10-01

... cylinder must be insulated. The insulating material must be fire resistant. The insulation on non-evacuated.... If a vacuum is maintained in the insulation space, the evacuated jacket must be designed for a... must be such that the total heat transfer, from the atmosphere at ambient temperature to the contents...

49 CFR 178.57 - Specification 4L welded insulated cylinders.

Code of Federal Regulations, 2012 CFR

2012-10-01

... cylinder must be insulated. The insulating material must be fire resistant. The insulation on non-evacuated.... If a vacuum is maintained in the insulation space, the evacuated jacket must be designed for a... must be such that the total heat transfer, from the atmosphere at ambient temperature to the contents...

49 CFR 178.57 - Specification 4L welded insulated cylinders.

Code of Federal Regulations, 2014 CFR

2014-10-01

... cylinder must be insulated. The insulating material must be fire resistant. The insulation on non-evacuated.... If a vacuum is maintained in the insulation space, the evacuated jacket must be designed for a... must be such that the total heat transfer, from the atmosphere at ambient temperature to the contents...

Torsion Tests of Stiffened Circular Cylinders

NASA Technical Reports Server (NTRS)

Moore, R L; Wescoat, C

1944-01-01

The design of curved sheet panels to resist shear involves a consideration of several factors: the buckling resistance of the sheet, the stress at which buckling becomes permanent, and the strength which may be developed beyond the buckling limit by tension-field action. Although some experimental as well as theoretical work has been done on the buckling and tension-field phases of this problem, neither of these types of action appears to be very well understood. The problem is of sufficient importance from the standpoint of aircraft design, it is believed, to warrant further experimental investigation. This report presents the results of the first series of torsion tests of stiffened circular cylinders to be completed in connection with this study at Aluminum Research Laboratories. (author)

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.

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.

Water entry and exit of horizontal circular cylinders

NASA Astrophysics Data System (ADS)

Greenhow, M.; Moyo, S.

This paper describes fully nonlinear two-dimensional numerical calculations of the free-surface deformations of initially calm water caused by the forced motion of totally or partially submerged horizontal circular cylinders. The paper considers the following. (i) Totally submerged cylinders moving with constant velocity in vertical, horizontal or combined motions. Results are compared with the small-time asymptotic solution obtained by Tyvand and Milohin 1995. Their results, which are taken to third-order (which is when gravity terms first appear in the expansions), are in excellent agreement with the numerical calculations for small times; beyond this only the numerical method gives accurate results until the free surface breaks or the cylinder emerges from the free surface. Breaking can occur during exit due to strongly negative pressures arising on the cylinder surface, or during the downwards motion causing a free-surface depression which closes up rapidly, forming splashes. Downwards motion is also shown to give rise to high-frequency waves in some cases. (ii) The free-surface deformations, pressures and forces acting on a cylinder in vertical or oblique forced motion during engulfment when it submerges from being initially half-submerged. The initial stages, when the cylinder still pierces the free surface, specify the initial conditions for a separate program for a completely submerged body, thereby allowing complete engulfment to be studied. The free surface closes up violently over the top of the cylinder resulting in jet flow, which, while difficult to handle numerically, has been shown to be insignificant for the bulk flow and the cylinder pressures and forces.

JEL Cylinder is moved into Crawler Transporter No. 2

NASA Technical Reports Server (NTRS)

2002-01-01

KENNEDY SPACE CENTER, FLA. -- After technicians removed and replaced all of the 32 bearings located in the JEL (jacking, equalization and leveling) cylinders and reinstalled the 16 cylinders on Crawler Transporter No. 2, workers take the crawler for a test run. During routine inspections, technicians found cracks in some of the bearings in the 16 JEL cylinders on the vehicle. There are 16 cylinders and 32 bearings per crawler.

The Federal Cylinder Project: A Guide to Field Cylinder Collections in Federal Agencies. Volume 8, Early Anthologies.

ERIC Educational Resources Information Center

Lee, Dorothy Sara, Ed; And Others

This catalog describes wax cylinder recordings of music collected by two pioneers in ethnomusicology. The 101 cylinders in the Benjamin Ives Gilman Collection recorded at the 1893 World's Columbian Exposition in Chicago contain Fijian, Samoan, Uvean, Javanese, Turkish, and Kwakiutl or Vancouver Island Indian music. The Gilman Collection is…

Spatial atomic layer deposition on flexible substrates using a modular rotating cylinder reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharma, Kashish; Hall, Robert A.; George, Steven M., E-mail: Steven.George@Colorado.Edu

2015-01-15

Spatial atomic layer deposition (ALD) is a new version of ALD based on the separation of reactant gases in space instead of time. In this paper, the authors present results for spatial ALD on flexible substrates using a modular rotating cylinder reactor. The design for this reactor is based on two concentric cylinders. The outer cylinder remains fixed and contains a series of slits. These slits can accept a wide range of modules that attach from the outside. The modules can easily move between the various slit positions and perform precursor dosing, purging, or pumping. The inner cylinder rotates withmore » the flexible substrate and passes underneath the various spatially separated slits in the outer cylinder. Trimethyl aluminum and ozone were used to grow Al{sub 2}O{sub 3} ALD films at 40 °C on metallized polyethylene terephthalate (PET) substrates to characterize this spatial ALD reactor. Spectroscopic ellipsometry measurements revealed a constant Al{sub 2}O{sub 3} ALD growth rate of 1.03 Å/cycle with rotation speeds from 40 to 100 RPM with the outer cylinder configured for one Al{sub 2}O{sub 3} ALD cycle per rotation. The Al{sub 2}O{sub 3} ALD growth rate then decreased at higher rotation rates for reactant residence times < 5 ms. The Al{sub 2}O{sub 3} ALD films were also uniform to within <1% across the central portion of metallized PET substrate. Fixed deposition time experiments revealed that Al{sub 2}O{sub 3} ALD films could be deposited at 2.08 Å/s at higher rotation speeds of 175 RPM. Even faster deposition rates are possible by adding more modules for additional Al{sub 2}O{sub 3} ALD cycles for every one rotation of the inner cylinder.« less

Hot piston ring/cylinder liner materials: Selection and evaluation

NASA Technical Reports Server (NTRS)

Sliney, Harold E.

1988-01-01

In current designs of the automotive (kinematic) Stirling engine, the piston rings are made of a reinforced polymer and are located below the pistons because they cannot withstand the high temperatures in the upper cylinder area. Theoretically, efficiency could be improved if hot piston rings were located near the top of the pistons. Described is a program to select piston ring and cylinder coating materials to test this theory. Candidate materials were screened, then subjected to a pin or disk friction and wear test machine. Tests were performed in hydrogen at specimen temperatures up to 760 C to simulate environmental conditions in the region of the hot piston ring reversal. Based on the results of these tests, a cobalt based alloy, Stellite 6B, was chosen for the piston rings and PS200, which consists of a metal-bonded chromium carbide matrix with dispersed solid lubricants, was chosen as the cylinder coating. Tests of a modified engine and a baseline engine showed that the hot ring reduced specific fuel consumption by up to 7 percent for some operating conditions and averaged about 3 percent for all conditions evaluated. Related applications of high-temperature coatings for shaft seals and as back-up lubricants are also described.

Unsteady characteristics of low-Re flow past two tandem cylinders

NASA Astrophysics Data System (ADS)

Zhang, Wei; Dou, Hua-Shu; Zhu, Zuchao; Li, Yi

2018-06-01

This study investigated the two-dimensional flow past two tandem circular or square cylinders at Re = 100 and D / d = 4-10, where D is the center-to-center distance and d is the cylinder diameter. Numerical simulation was performed to comparably study the effect of cylinder geometry and spacing on the aerodynamic characteristics, unsteady flow patterns, time-averaged flow characteristics and flow unsteadiness. We also provided the first global linear stability analysis and sensitivity analysis on the physical problem for the potential application of flow control. The objective of this work is to quantitatively identify the effect of the cylinder geometry and spacing on the characteristic quantities. Numerical results reveal that there is wake flow transition for both geometries depending on the spacing. The characteristic quantities, including the time-averaged and fluctuating streamwise velocity and pressure coefficient, are quite similar to that of the single cylinder case for the upstream cylinder, while an entirely different variation pattern is observed for the downstream cylinder. The global linear stability analysis shows that the spatial structure of perturbation is mainly observed in the wake of the downstream cylinder for small spacing, while moves upstream with reduced size and is also observed after the upstream cylinder for large spacing. The sensitivity analysis reflects that the temporal growth rate of perturbation is the most sensitive to the near-wake flow of downstream cylinder for small spacing and upstream cylinder for large spacing.

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.

Active aerodynamic drag reduction on morphable cylinders

NASA Astrophysics Data System (ADS)

Guttag, M.; Reis, P. M.

2017-12-01

We study a mechanism for active aerodynamic drag reduction on morphable grooved cylinders, whose topography can be modified pneumatically. Our design is inspired by the morphology of the Saguaro cactus (Carnegiea gigantea), which possesses an array of axial grooves, thought to help reduce aerodynamic drag, thereby enhancing the structural robustness of the plant under wind loading. Our analog experimental samples comprise a spoked rigid skeleton with axial cavities, covered by a stretched elastomeric film. Decreasing the inner pressure of the sample produces axial grooves, whose depth can be accurately varied, on demand. First, we characterize the relation between groove depth and pneumatic loading through a combination of precision mechanical experiments and finite element simulations. Second, wind tunnel tests are used to measure the aerodynamic drag coefficient (as a function of Reynolds number) of the grooved samples, with different levels of periodicity and groove depths. We focus specifically on the drag crisis and systematically measure the associated minimum drag coefficient and the critical Reynolds number at which it occurs. The results are in agreement with the classic literature of rough cylinders, albeit with an unprecedented level of precision and resolution in varying topography using a single sample. Finally, we leverage the morphable nature of our system to dynamically reduce drag for varying aerodynamic loading conditions. We demonstrate that actively controlling the groove depth yields a drag coefficient that decreases monotonically with Reynolds number and is significantly lower than the fixed sample counterparts. These findings open the possibility for the drag reduction of grooved cylinders to be operated over a wide range of flow conditions.

Size effect and cylinder test on several commercial explosives

NASA Astrophysics Data System (ADS)

Souers, P. Clark; Lauderbach, Lisa; Moua, Kou; Garza, Raul

2012-03-01

Some size (diameter) effect and the Cylinder test results for Kinepak (ammonium nitrate/nitromethane), Semtex 1, Semtex H and urea nitrate are presented. Cylinder test data appears normal despite faster sound speeds in the copper wall. Most explosives come to steady state in the Cylinder test as expected, but Kinepak shows a steadily increasing wall velocity with distance down the cylinder. Some data on powder densities as a function of loading procedure are also given.

Stability of Capillary Surfaces in Rectangular Containers: The Right Square Cylinder

NASA Technical Reports Server (NTRS)

Weislogel, M. M.; Hsieh, K. C.

1998-01-01

The linearized governing equations for an ideal fluid are presented for numerical analysis for the stability of free capillary surfaces in rectangular containers against unfavorable disturbances (accelerations,i.e. Rayleigh-Taylor instability). The equations are solved for the case of the right square cylinder. The results are expressed graphically in term of a critical Bond number as a function of system contact angle. A critical wetting phenomena in the corners is shown to significantly alter the region of stability for such containers in contrast to simpler geometries such as the right circular cylinder or the infinite rectangular slot. Such computational results provide additional constraints for the design of fluids systems for space-based applications.

Stresses in and General Instability of Monocoque Cylinders with Cutouts I : Experimental Investigation of Cylinders with a Symmetric Cutout Subjected to Pure Bending

NASA Technical Reports Server (NTRS)

Hoff, N J; Boley, Bruno A

1946-01-01

Ten 24S-T alclad cylinders of 20-inch diameter, 45- or 58-inch length, and 0.012-inch wall thickness, reinforced with 24S-T aluminum alloy stringers and rings were tested in pure bending. In the middle of the compression side of the cylinders there was a cutout extending over 19 inches in the longitudinal direction, and over an angle of 45 degrees, 90 degrees, or 135 degrees in the circumferential direction. The strain in the stringers and in the sheet covering was measured with metal electric strain gages. The stress distribution in the cylinders deviate considerably from the linear law valid for cylinders without a cutout. The maximum strain measured was about four-thirds of the value calculated from the Mc/I formula when I was taken as the moment of inertia of the cross section of the portion of the cylinder where the cutout was situated. A diagram is presented containing the strain factors defined as the ratios of measured strain to strain calculated with the Mc/I formula. All the 10 cylinders tested failed in general instability. Two symmetric and one antisymmetric pattern of buckling were observed and the buckling load appeared to be independent of the method of manufacture and the length of the cylinder. The buckling load of the cylinders having cutouts extending over 45 degrees, 90 degrees, and 135 degrees was 66, 47, and 31 percent, respectively, of the buckling load of the cylinder without a cutout.

Heat-transfer processes in air-cooled engine cylinders

NASA Technical Reports Server (NTRS)

Pinkel, Benjamin

1938-01-01

From a consideration of heat-transfer theory, semi-empirical expressions are set up for the transfer of heat from the combustion gases to the cylinder of an air-cooled engine and from the cylinder to the cooling air. Simple equations for the average head and barrel temperatures as functions of the important engine and cooling variables are obtained from these expressions. The expressions involve a few empirical constants, which may be readily determined from engine tests. Numerical values for these constants were obtained from single-cylinder engine tests for cylinders of the Pratt & Whitney 1535 and 1340-h engines. The equations provide a means of calculating the effect of the various engine and cooling variables on the cylinder temperatures and also of correlating the results of engine cooling tests. An example is given of the application of the equations to the correlation of cooling-test data obtained in flight.

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.

Sharp focusing of laser light by multilayer cylinders with circular cross-section

NASA Astrophysics Data System (ADS)

Kozlova, E. S.

2018-04-01

In this paper, the focusing of laser light at 532 nm by dielectric cylinders with a metal shells is studied by using COMSOL Multiphysics. The analysis of cylinder design which proposed multilayered shell shows that a microcylinder with a gold-silver (or silver-gold) shell can improve the focusing process, especially in the case of TM polarization. The microcylinder with thin internal silver layer of 1 nm and outside gold layer of 9 nm focus TE-polarized light to nanojet with maximal intensity of 5.65 a.u., full width and full length at half maximum of intensity of of 0.39λ and 0.72λ, respectively.

Sub-grid drag model for immersed vertical cylinders in fluidized beds

DOE PAGES

Verma, Vikrant; Li, Tingwen; Dietiker, Jean -Francois; ...

2017-01-03

Immersed vertical cylinders are often used as heat exchanger in gas-solid fluidized beds. Computational Fluid Dynamics (CFD) simulations are computationally expensive for large scale systems with bundles of cylinders. Therefore sub-grid models are required to facilitate simulations on a coarse grid, where internal cylinders are treated as a porous medium. The influence of cylinders on the gas-solid flow tends to enhance segregation and affect the gas-solid drag. A correction to gas-solid drag must be modeled using a suitable sub-grid constitutive relationship. In the past, Sarkar et al. have developed a sub-grid drag model for horizontal cylinder arrays based on 2Dmore » simulations. However, the effect of a vertical cylinder arrangement was not considered due to computational complexities. In this study, highly resolved 3D simulations with vertical cylinders were performed in small periodic domains. These simulations were filtered to construct a sub-grid drag model which can then be implemented in coarse-grid simulations. Gas-solid drag was filtered for different solids fractions and a significant reduction in drag was identified when compared with simulation without cylinders and simulation with horizontal cylinders. Slip velocities significantly increase when vertical cylinders are present. Lastly, vertical suspension drag due to vertical cylinders is insignificant however substantial horizontal suspension drag is observed which is consistent to the finding for horizontal cylinders.« less

The nonlinear bending response of thin-walled laminated composite cylinders

NASA Technical Reports Server (NTRS)

Fuchs, Hannes P.; Hyer, Michael W.

1992-01-01

The geometrically nonlinear Donnell shell theory is applied to the problem of stable bending of thin-walled circular cylinders. Responses are computed for cylinders with a radius-to-thickness ratio of 50 and length-to-radius ratios of 1 and 5. Four laminated composite cylinders and an aluminum cylinder are considered. Critical moment estimates are presented for short cylinders for which compression-type buckling behavior is important, and for very long cylinders for which the cross-section flattening, i.e., Brazier effect, is important. A finite element analysis is used to estimate the critical end rotation in addition to establishing the range of validity of the prebuckling analysis. The radial displacement response shows that the character of the boundary layer is significantly influenced by the geometric nonlinearities. Application of a first ply failure analysis using the maximum stress criterion suggests that in nearly all instances material failure occurs before buckling. Failure of the composite cylinders can be attributed to fiber breakage. Striking similarities are seen between the prebuckling displacements of the bending problem and axial compression problem for short cylinders.

Recording Rapidly Changing Cylinder-wall Temperatures

NASA Technical Reports Server (NTRS)

Meier, Adolph

1942-01-01

The present report deals with the design and testing of a measuring plug suggested by H. Pfriem for recording quasi-stationary cylinder wall temperatures. The new device is a resistance thermometer, the temperature-susceptible part of which consists of a gold coating applied by evaporation under high vacuum and electrolytically strengthened. After overcoming initial difficulties, calibration of plugs up to and beyond 400 degrees C was possible. The measurements were made on high-speed internal combustion engines. The increasing effect of carbon deposit at the wall surface with increasing operating period is indicated by means of charts.

Means and method of balancing multi-cylinder reciprocating machines

DOEpatents

Corey, John A.; Walsh, Michael M.

1985-01-01

A virtual balancing axis arrangement is described for multi-cylinder reciprocating piston machines for effectively balancing out imbalanced forces and minimizing residual imbalance moments acting on the crankshaft of such machines without requiring the use of additional parallel-arrayed balancing shafts or complex and expensive gear arrangements. The novel virtual balancing axis arrangement is capable of being designed into multi-cylinder reciprocating piston and crankshaft machines for substantially reducing vibrations induced during operation of such machines with only minimal number of additional component parts. Some of the required component parts may be available from parts already required for operation of auxiliary equipment, such as oil and water pumps used in certain types of reciprocating piston and crankshaft machine so that by appropriate location and dimensioning in accordance with the teachings of the invention, the virtual balancing axis arrangement can be built into the machine at little or no additional cost.

77 FR 37712 - High Pressure Steel Cylinders From China

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-22

... Pressure Steel Cylinders From China Determinations On the basis of the record \\1\\ developed in the subject... cylinders from China, provided for in subheading 7311.00.00 of the Harmonized Tariff Schedule of the United... preliminary determinations by Commerce that imports of high pressure steel cylinders from China were...

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.

Investigation of Primary Mathematics Student Teachers' Concept Images: Cylinder and Cone

ERIC Educational Resources Information Center

Ertekin, Erhan; Yazici, Ersen; Delice, Ali

2014-01-01

The aim of the present study is to determine the influence of concept definitions of cylinder and cone on primary mathematics student teachers' construction of relevant concept images. The study had a relational survey design and the participants were 238 primary mathematics student teachers. Statistical analyses implied the following: mathematics…

Steady flow past a vertical surface-piercing circular cylinder

NASA Astrophysics Data System (ADS)

Chaplin, J. R.; Teigen, P.

2003-09-01

This paper describes experiments in which a vertical surface-piercing circular cylinder with a large draught was towed at steady speeds through water initially at rest. The cylinder diameter d was 210mm, and measurements were made of pressures around its circumference at elevations between 2.4d below still water level to 0.7d above, at Froude numbers (based on d) up to 1.67. The tests were carried out at a constant ratio of Reynolds number to Froude number of 2.79×105. The total resistance coefficient reached a maximum at a Froude number of about 1, when that part of the loading that can be attributed to the presence of the free surface was equivalent to the submerged form drag on a length of cylinder of about 0.9d. Measurements are also presented of the run-up on the front of the cylinder and of the depth of the depression at the back. Previous measurements by Hay (Flow about Semi-submerged Cylinders of Finite Length. Princeton University Report, Princeton, NJ, 1947) for the case of a cylinder with a submerged free end, and by Hsieh (Proc. Am. Soc. Civil Eng. 90 (1964) 161) of forces on cylinders standing on the floor of an open channel, are reanalysed. In most respects these results are found to be compatible with the present data for a cylinder of large draught.

Beating motion of a circular cylinder in vortex-induced vibrations

NASA Astrophysics Data System (ADS)

Shen, Linwei; Chan, Eng-Soon; Wei, Yan

2018-04-01

In this paper, beating phenomenon of a circular cylinder in vortex-induced vibration is studied by numerical simulations in a systematic manner. The cylinder mass coefficients of 2 and 10 are considered, and the Reynolds number is 150. Two distinctive frequencies, namely cylinder oscillation and vortex shedding frequencies, are obtained from the harmonic analysis of the cylinder displacement. The result is consistent with that observed in laboratory experiments. It is found that the cylinder oscillation frequency changes with the natural frequency of the cylinder while the reduced velocity is varied. The added-mass coefficient of the cylinder in beating motion is therefore estimated. Meanwhile, the vortex shedding frequency does not change dramatically in the beating situations. In fact, it is very close to 0.2. Accordingly, the lift force coefficient has two main components associated with these two frequencies. Besides, higher harmonics of the cylinder oscillation frequency appear in the spectrum of the lift coefficient. Moreover, the vortex shedding timing is studied in the beating motion by examining the instantaneous flow fields in the wake, and two scenarios of the vortex formation are observed.

77 FR 1975 - Safety Advisory: Unauthorized Marking of Compressed Gas Cylinders

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-12

... Jackson Plaza, Ann Arbor, MI improperly requalified and marked high pressure compressed gas cylinders... DOT specification cylinders after its authority to requalifiy high pressure cylinders expired on... that Spears Fire & Safety continued to requalify and mark high pressure cylinders after their authority...

Studies on shock interactions with moving cylinders using immersed boundary method

NASA Astrophysics Data System (ADS)

Luo, Kun; Luo, Yujuan; Jin, Tai; Fan, Jianren

2017-06-01

The process of shock interaction with a rigid cylinder is studied using a compressible immersed boundary method combined with a high-order weighted essentially nonoscillatory scheme. Movement of the cylinder is coupled to the flow field. First, the accuracy of the numerical scheme is validated. Then the influences of the incident shock Mach number and the cylinder diameter are discussed. The results are compared with those from cases with stationary cylinders. It is found that variation of either the incident shock Mach number or the cylinder diameter can cause different schlieren images. At a given dimensionless time, the trajectory of the upper triple point varies nonmonotonically with the incident shock Mach number while the primary reflected shock gets closer to the cylinder with increasing incident shock Mach number. For any moving case with a given incident shock Mach number and cylinder diameter, the trajectory of the upper triple point, the time evolution of the normalized vertical distance from the highest point of the primary reflected shock to the centerline of the cylinder, and the time evolution of the normalized shock detachment distance can all be predicted by linear correlation. As for the time evolution of the force exerted on the cylinder, the peak of the moving cylinder appears earlier than the stationary one in dimensionless time, with much lower value. Correlations to predict the occurrence of the peak drag and its value under different shock Mach numbers and cylinder diameters are proposed. The resulting cylinder movement is also briefly discussed.

Characterizing dilute combustion instabilities in a multi-cylinder spark-ignited engine using symbolic analysis

DOE PAGES

Daw, C. Stuart; Finney, Charles E. A.; Kaul, Brian C.; ...

2014-12-29

Spark-ignited internal combustion engines have evolved considerably in recent years in response to increasingly stringent regulations for emissions and fuel-economy. One new advanced engine strategy utilizes high levels of exhaust gas recirculation (EGR) to reduce combustion temperatures, thereby increasing thermodynamic efficiency and reducing nitrogen oxide emissions. While this strategy can be highly effective, it also poses major control and design challenges due to the large combustion oscillations that develop at sufficiently high EGR levels. Previous research has documented that combustion instabilities can propagate between successive engine cycles in individual cylinders via self-generated feedback of reactive species and thermal energy inmore » the retained residual exhaust gases. In this work, we use symbolic analysis to characterize multi-cylinder combustion oscillations in an experimental engine operating with external EGR. At low levels of EGR, intra-cylinder oscillations are clearly visible and appear to be associated with brief, intermittent coupling among cylinders. As EGR is increased further, a point is reached where all four cylinders lock almost completely in phase and alternate simultaneously between two distinct bi-stable combustion states. From a practical perspective, it is important to understand the causes of this phenomenon and develop diagnostics that might be applied to ameliorate its effects. We demonstrate here that two approaches for symbolizing the engine combustion measurements can provide useful probes for characterizing these instabilities.« less

78 FR 16044 - Hazardous Materials Packaging-Composite Cylinder Standards; Public Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-13

.... PHMSA-2013-0017; Notice No. 13-02] Hazardous Materials Packaging--Composite Cylinder Standards; Public..., marking, sale and use of non-DOT specification composite cylinders. The non-DOT specification cylinders... Organization (ISO) standards for composite cylinders ISO 11119 Parts - 1, -2, -3 incorporated by reference into...

Transient performance analysis of the master cylinder hydraulic system of a 6.3 MN fineblanking press

NASA Astrophysics Data System (ADS)

Yi, Guodong; Li, Jin

2018-03-01

The master cylinder hydraulic system is the core component of the fineblanking press that seriously affects the machine performance. A key issue in the design of the master cylinder hydraulic system is dealing with the heavy shock loads in the fineblanking process. In this paper, an equivalent model of the master cylinder hydraulic system is established based on typical process parameters for practical fineblanking; then, the response characteristics of the master cylinder slider to the step changes in the load and control current are analyzed, and lastly, control strategies for the proportional valve are studied based on the impact of the control parameters on the kinetic stability of the slider. The results show that the kinetic stability of the slider is significantly affected by the step change of the control current, while it is slightly affected by the step change of the system load, which can be improved by adjusting the flow rate and opening time of the proportional valve.

Revised model for the radiation force exerted by standing surface acoustic waves on a rigid cylinder

NASA Astrophysics Data System (ADS)

Liang, Shen; Chaohui, Wang

2018-03-01

In this paper, a model for the radiation force exerted by standing surface acoustic waves (SSAWs) on a rigid cylinder in inviscid fluids is extended to account for the dependence on the Rayleigh angle. The conventional model for the radiation force used in the SSAW-based applications is developed in plane standing waves, which fails to predict the movement of the cylinder in the SSAW. Our revised model reveals that, in the direction normal to the piezoelectric substrate on which the SSAW is generated, acoustic radiation force can be large enough to drive the cylinder even in the long-wavelength limit. Furthermore, the force in this direction can not only push the cylinder away, but also pull it back toward the substrate. In the direction parallel to the substrate, the equilibrium positions for particles can be actively tuned by changing Rayleigh angle. As an example considered in the paper, with the reduction of Rayleigh angle the equilibrium positions for steel cylinders in water change from pressure nodes to pressure antinodes. The model can thus be used in the design of SSAWs for particle manipulations.

Numerical and experimental investigation of the bending response of thin-walled composite cylinders

NASA Technical Reports Server (NTRS)

Fuchs, J. P.; Hyer, M. W.; Starnes, J. H., Jr.

1993-01-01

A numerical and experimental investigation of the bending behavior of six eight-ply graphite-epoxy circular cylinders is presented. Bending is induced by applying a known end-rotation to each end of the cylinders, analogous to a beam in bending. The cylinders have a nominal radius of 6 inches, a length-to-radius ratio of 2 and 5, and a radius-to-thickness ratio of approximately 160. A (+/- 45/0/90)S quasi-isotropic layup and two orthotropic layups, (+/- 45/0 sub 2)S and (+/- 45/90 sub 2)S, are studied. A geometrically nonlinear special-purpose analysis, based on Donnell's nonlinear shell equations, is developed to study the prebuckling responses and gain insight into the effects of non-ideal boundary conditions and initial geometric imperfections. A geometrically nonlinear finite element analysis is utilized to compare with the prebuckling solutions of the special-purpose analysis and to study the buckling and post buckling responses of both geometrically perfect and imperfect cylinders. The imperfect cylinder geometries are represented by an analytical approximation of the measured shape imperfections. Extensive experimental data are obtained from quasi-static tests of the cylinders using a test fixture specifically designed for the present investigation. A description of the test fixture is included. The experimental data are compared to predictions for both perfect and imperfect cylinder geometries. Prebuckling results are presented in the form of displacement and strain profiles. Buckling end-rotations, moments, and strains are reported, and predicted mode shapes are presented. Observed and predicted moment vs. end-rotation relations, deflection patterns, and strain profiles are illustrated for the post buckling responses. It is found that a geometrically nonlinear boundary layer behavior characterizes the prebuckling responses. The boundary layer behavior is sensitive to laminate orthotropy, cylinder geometry, initial geometric imperfections, applied end

Innovative design of composite structures: Axisymmetric deformations of unsymmetrically laminated cylinders loaded in axial compression

NASA Technical Reports Server (NTRS)

Hyer, M. W.; Paraska, P. J.

1990-01-01

The study focuses on the axisymmetric deformation response of unsymmetrically laminate cylinders loaded in axial compression by known loads. A geometrically nonlinear analysis is used. Though buckling is not studied, the deformations can be considered to be the prebuckling response. Attention is directed at three 16 layer laminates: a (90 sub 8/0 sub 8) sub T; a (0 sub 8/90 sub 8) sub T and a (0/90) sub 4s. The symmetric laminate is used as a basis for comparison, while the two unsymmetric laminates were chosen because they have equal but opposite bending-stretching effects. Particular attention is given to the influence of the thermally-induced preloading deformations that accompany the cool-down of any unsymmetric laminate from the consolidation temperature. Simple support and clamped boundary conditions are considered. It is concluded that: (1) The radial deformations of an unsymmetric laminate are significantly larger than the radial deformations of a symmetric laminate, although for both symmetric and unsymmetric laminates the large deformations are confined to a boundary layer near the ends of the cylinder; (2) For this nonlinear problem the length of the boundary layer is a function of the applied load; (3) The sign of the radial deformations near the supported end of the cylinder depends strongly on the sense (sign) of the laminate asymmetry; (4) For unsymmetric laminates, ignoring the thermally-induced preloading deformations that accompany cool-down results in load-induced deformations that are under predicted; and (5) The support conditions strongly influence the response but the influence of the sense of asymmetry and the influence of the thermally-induced preloading deformations are independent of the support conditions.

The Stability Region for Feedback Control of the Wake Behind Twin Oscillating Cylinders

NASA Astrophysics Data System (ADS)

Borggaard, Jeff; Gugercin, Serkan; Zietsman, Lizette

2016-11-01

Linear feedback control has the ability to stabilize vortex shedding behind twin cylinders where cylinder rotation is the actuation mechanism. Complete elimination of the wake is only possible for certain Reynolds numbers and cylinder spacing. This is related to the presence of asymmetric unstable modes in the linearized system. We investigate this region of parameter space using a number of closed-loop simulations that bound this region. We then consider the practical issue of designing feedback controls based on limited state measurements by building a nonlinear compensator using linear robust control theory with and incorporating the nonlinear terms in the compensator (e.g., using the extended Kalman filter). Interpolatory model reduction methods are applied to the large discretized, linearized Navier-Stokes system and used for computing the control laws and compensators. Preliminary closed-loop simulations of a three-dimensional version of this problem will also be presented. Supported in part by the National Science Foundation.

Alternatives to Rare Earth Permanent Magnets for Energy Harvesting Applications

NASA Astrophysics Data System (ADS)

Khazdozian, Helena; Hadimani, Ravi; Jiles, David

Direct-drive permanent magnet generators (DDPMGs) offer increased reliability and efficiency over the more commonly used geared doubly-fed induction generator, yet are only employed in less than 1 percent of utility scale wind turbines in the U.S. One major barrier to increased deployment of DDPMGs in the U.S. wind industry is NdFeB permanent magnets (PMs), which contain critical rare earth elements Nd and Dy. To allow for the use of rare earth free PMs, the magnetic loading, defined as the average magnetic flux density over the rotor surface, must be maintained. Halbach cylinders are employed in 3.5kW Halbach PMGs (HPMGs) of varying slot-to-pole ratio to concentrate the magnetic flux output by a lower energy density PM over the rotor surface. We found that for high pole and slot number, the increase in magnetic loading is sufficient to allow for the use of strontium iron oxide hard ferrite PMs and achieved rated performance. Joule losses in the stator windings were found to increase for the hard ferrite PMs due to increased inductance in the stator windings. However, for scaling of the HPMG designs to 3MW, rated performance and high efficiency were achieved, demonstrating the potential for elimination for rare earth PMs in commercial scale wind turbines. This work was supported by the National Science Foundation under Grant No. 1069283 and a Barbara and James Palmer Endowment at Iowa State University.

Results of a study of Mach number and Reynolds number effects on the crossflow drag characteristics of ogive cylinders and ogive-cylinder-frustum-cylinders at angles of attack to 30 degrees

NASA Technical Reports Server (NTRS)

Foley, J. E.

1971-01-01

An analysis was made to determine the effects of Mach number and Reynolds number on the local and total crossflow drag characteristics of ogive-cylinders and ogive-cylinder-frustum-cylinders at angles of the MSFC 14 in TWT and the LTV 4 ft HSWT, and pressure data obtained in the TWT, at Mach numbers 0.14, 0.8, 1.2, and 2.0, and a wide range of Reynolds numbers. Results indicate that the streamwise Reynolds number, VD/nusin alpha, is an important correlation parameter in the subcritical Reynolds number range at imcompressible speeds and that the crossflow Mach number correlates compressibility effects.

Nonideal ultrathin mantle cloak for electrically large conducting cylinders.

PubMed

Liu, Shuo; Zhang, Hao Chi; Xu, He-Xiu; Cui, Tie Jun

2014-09-01

Based on the concept of the scattering cancellation technique, we propose a nonideal ultrathin mantle cloak that can efficiently suppress the total scattering cross sections of an electrically large conducting cylinder (over one free-space wavelength). The cloaking mechanism is investigated in depth based on the Mie scattering theory and is simultaneously interpreted from the perspective of far-field bistatic scattering and near-field distributions. We remark that, unlike the perfect transformation-optics-based cloak, this nonideal cloaking technique is mainly designed to minimize simultaneously several scattering multipoles of a relatively large geometry around considerably broad bandwidth. Numerical simulations and experimental results show that the antiscattering ability of the metasurface gives rise to excellent total scattering reduction of the electrically large cylinder and remarkable electric-field restoration around the cloak. The outstanding cloaking performance together with the good features of and ultralow profile, flexibility, and easy fabrication predict promising applications in the microwave frequencies.

Dynamical instability of a charged gaseous cylinder

NASA Astrophysics Data System (ADS)

Sharif, M.; Mumtaz, Saadia

2017-10-01

In this paper, we discuss dynamical instability of a charged dissipative cylinder under radial oscillations. For this purpose, we follow the Eulerian and Lagrangian approaches to evaluate linearized perturbed equation of motion. We formulate perturbed pressure in terms of adiabatic index by applying the conservation of baryon numbers. A variational principle is established to determine characteristic frequencies of oscillation which define stability criteria for a gaseous cylinder. We compute the ranges of radii as well as adiabatic index for both charged and uncharged cases in Newtonian and post-Newtonian limits. We conclude that dynamical instability occurs in the presence of charge if the gaseous cylinder contracts to the radius R*.

Direct adaptive fuzzy control of a translating piezoelectric flexible manipulator driven by a pneumatic rodless cylinder

NASA Astrophysics Data System (ADS)

Qiu, Zhi-cheng; Wang, Bin; Zhang, Xian-min; Han, Jian-da

2013-04-01

This study presents a novel translating piezoelectric flexible manipulator driven by a rodless cylinder. Simultaneous positioning control and vibration suppression of the flexible manipulator is accomplished by using a hybrid driving scheme composed of the pneumatic cylinder and a piezoelectric actuator. Pulse code modulation (PCM) method is utilized for the cylinder. First, the system dynamics model is derived, and its standard multiple input multiple output (MIMO) state-space representation is provided. Second, a composite proportional derivative (PD) control algorithms and a direct adaptive fuzzy control method are designed for the MIMO system. Also, a time delay compensation algorithm, bandstop and low-pass filters are utilized, under consideration of the control hysteresis and the caused high-frequency modal vibration due to the long stroke of the cylinder, gas compression and nonlinear factors of the pneumatic system. The convergence of the closed loop system is analyzed. Finally, experimental apparatus is constructed and experiments are conducted. The effectiveness of the designed controllers and the hybrid driving scheme is verified through simulation and experimental comparison studies. The numerical simulation and experimental results demonstrate that the proposed system scheme of employing the pneumatic drive and piezoelectric actuator can suppress the vibration and achieve the desired positioning location simultaneously. Furthermore, the adopted adaptive fuzzy control algorithms can significantly enhance the control performance.

Damage tolerance of pressurized graphite/epoxy tape cylinders under uniaxial and biaxial loading. M.S. Thesis

NASA Technical Reports Server (NTRS)

Priest, Stacy Marie

1993-01-01

The damage tolerance behavior of internally pressurized, axially slit, graphite/epoxy tape cylinders was investigated. Specifically, the effects of axial stress, structural anisotropy, and subcritical damage were considered. In addition, the limitations of a methodology which uses coupon fracture data to predict cylinder failure were explored. This predictive methodology was previously shown to be valid for quasi-isotropic fabric and tape cylinders but invalid for structurally anisotropic (+/-45/90)(sub s) and (+/-45/0)(sub s) cylinders. The effects of axial stress and structural anisotropy were assessed by testing tape cylinders with (90/0/+/-45)(sub s), (+/-45/90)(sub s), and (+/-45/0)(sub s) layups in a uniaxial test apparatus, specially designed and built for this work, and comparing the results to previous tests conducted in biaxial loading. Structural anisotropy effects were also investigated by testing cylinders with the quasi-isotropic (0/+/-45/90)(sub s) layup which is a stacking sequence variation of the previously tested (90/0/+/-45)(sub s) layup with higher D(sub 16) and D(sub 26) terms but comparable D(sub 16) and D(sub 26) to D(sub 11) ratios. All cylinders tested and used for comparison are made from AS4/3501-6 graphite/epoxy tape and have a diameter of 305 mm. Cylinder slit lengths range from 12.7 to 50.8 mm. Failure pressures are lower for the uniaxially loaded cylinders in all cases. The smallest percent failure pressure decreases are observed for the (+/-45/90)(sub s) cylinders, while the greatest such decreases are observed for the (+/-45/0)(sub s) cylinders. The relative effects of the axial stress on the cylinder failure pressures do not correlate with the degree of structural coupling. The predictive methodology is not applicable for uniaxially loaded (+/-45/90)(sub s) and (+/-45/0)(sub s) cylinders, may be applicable for uniaxially loaded (90/0/+/-45)(sub s) cylinders, and is applicable for the biaxially loaded (90/0/+/-45)(sub s) and (0

SU-G-206-06: Analytic Dose Function for CT Scans in Infinite Cylinders as a Function of Scan Length and Cylinder Radius

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bakalyar, D; Feng, W; McKenney, S

Purpose: The radiation dose absorbed at a particular radius ρ within the central plane of a long cylinder following a CT scan is a function of the length of the scan L and the cylinder radius R along with kVp and cylinder composition. An analytic function was created that that not only expresses these dependencies but is integrable in closed form over the area of the central plane. This feature facilitates explicit calculation of the planar average dose. The “approach to equilibrium” h(L) discussed in the TG111 report is seamlessly included in this function. Methods: For a cylindrically symmetric radiationmore » field, Monte Carlo calculations were performed to compute the dose distribution to long polyethylene cylinders for scans of varying L for cylinders ranging in radius from 5 to 20 cm. The function was developed from the resultant Monte Carlo data. In addition, the function was successfully fit to data taken from measurements on the 30 cm diameter ICRU/TG200 phantom using a real-time dosimeter. Results: Symmetry and continuity dictate a local extremum at the center which is a minimum for the larger sizes. There are competing effects as the beam penetrates the cylinder from the outside: attenuation, resulting in a decrease; scatter, abruptly increasing at the circumference. This competition may result in an absolute maximum between the center and outer edge leading to a “gull wing” shape for the radial dependence. For the smallest cylinders, scatter may dominate to the extent that there is an absolute maximum at the center. Conclusion: An integrable, analytic function has been developed that provides the radial dependency of dose for the central plane of a scan of length L for cylinders of varying diameter. Equivalently, we have developed h(L,R,ρ).« less

Analysis of thermoelastic characteristics in a thick walled FGM cylinder

NASA Astrophysics Data System (ADS)

Tanvir, A. N. M.; Islam, Md. Didarul; Ahmed, Faisal

2017-12-01

This study is concerned with the behavior of stress and strain in a thick walled functionally graded material (FGM) cylinder under internal pressure. The incompatible eigenstrain and equivalent eigenstrain developed in the cylinder, are taken into account. As a demonstration, a TiC/Al2O3 FGM cylinder is considered and different components of stress and strain are presented in order to study the effects of internal pressure, temperature difference (between room and sintering temperature), cylinder wall thickness and material distribution. The numerical result presented here shows that the thermoelastic characteristic like stress and strain of an FGM cylinder is significantly influenced by some of the above-mentioned parameters and can be controlled by properly controlling these parameters.

Nonlinear Deformation of a Piecewise Homogeneous Cylinder Under the Action of Rotation

NASA Astrophysics Data System (ADS)

Akhundov, V. M.; Kostrova, M. M.

2018-05-01

Deformation of a piecewise cylinder under the action of rotation is investigated. The cylinder consists of an elastic matrix with circular fibers of square cross section made of a more rigid elastic material and arranged doubly periodically in the cylinder. Behavior of the cylinder under large displacements and deformations is examined using the equations of a nonlinear elasticity theory for cylinder constituents. The problem posed is solved by the finite-difference method using the method of continuation with respect to the rotational speed of the cylinder.

Adaptive individual-cylinder thermal state control using piston cooling for a GDCI engine

DOEpatents

Roth, Gregory T; Husted, Harry L; Sellnau, Mark C

2015-04-07

A system for a multi-cylinder compression ignition engine includes a plurality of nozzles, at least one nozzle per cylinder, with each nozzle configured to spray oil onto the bottom side of a piston of the engine to cool that piston. Independent control of the oil spray from the nozzles is provided on a cylinder-by-cylinder basis. A combustion parameter is determined for combustion in each cylinder of the engine, and control of the oil spray onto the piston in that cylinder is based on the value of the combustion parameter for combustion in that cylinder. A method for influencing combustion in a multi-cylinder engine, including determining a combustion parameter for combustion taking place in in a cylinder of the engine and controlling an oil spray targeted onto the bottom of a piston disposed in that cylinder is also presented.

The three-dimensional flow past a rapidly rotating circular cylinder

NASA Technical Reports Server (NTRS)

Denier, James P.; Duck, Peter W.

1993-01-01

The high Reynolds number (Re) flow past a rapidly rotating circular cylinder is investigated. The rotation rate of the cylinder is allowed to vary (slightly) along the axis of the cylinder, thereby provoking three-dimensional flow disturbances, which are shown to involve relatively massive (O(Re)) velocity perturbations to the flow away from the cylinder surface. Additionally, three integral conditions, analogous to the single condition determined in two dimensions by Batchelor, are derived, based on the condition of periodicity in the azimuthal direction.

Buckling Imperfection Sensitivity of Axially Compressed Orthotropic Cylinders

NASA Technical Reports Server (NTRS)

Schultz, Marc R.; Nemeth, Michael P.

2010-01-01

Structural stability is a major consideration in the design of lightweight shell structures. However, the theoretical predictions of geometrically perfect structures often considerably over predict the buckling loads of inherently imperfect real structures. It is reasonably well understood how the shell geometry affects the imperfection sensitivity of axially compressed cylindrical shells; however, the effects of shell anisotropy on the imperfection sensitivity is less well understood. In the present paper, the development of an analytical model for assessing the imperfection sensitivity of axially compressed orthotropic cylinders is discussed. Results from the analytical model for four shell designs are compared with those from a general-purpose finite-element code, and good qualitative agreement is found. Reasons for discrepancies are discussed, and potential design implications of this line of research are discussed.

Characterizing dilute combustion instabilities in a multi-cylinder spark-ignited engine using symbolic analysis.

PubMed

Daw, C S; Finney, C E A; Kaul, B C; Edwards, K D; Wagner, R M

2015-02-13

Spark-ignited internal combustion engines have evolved considerably in recent years in response to increasingly stringent regulations for emissions and fuel economy. One new advanced engine strategy ustilizes high levels of exhaust gas recirculation (EGR) to reduce combustion temperatures, thereby increasing thermodynamic efficiency and reducing nitrogen oxide emissions. While this strategy can be highly effective, it also poses major control and design challenges due to the large combustion oscillations that develop at sufficiently high EGR levels. Previous research has documented that combustion instabilities can propagate between successive engine cycles in individual cylinders via self-generated feedback of reactive species and thermal energy in the retained residual exhaust gases. In this work, we use symbolic analysis to characterize multi-cylinder combustion oscillations in an experimental engine operating with external EGR. At low levels of EGR, intra-cylinder oscillations are clearly visible and appear to be associated with brief, intermittent coupling among cylinders. As EGR is increased further, a point is reached where all four cylinders lock almost completely in phase and alternate simultaneously between two distinct bi-stable combustion states. From a practical perspective, it is important to understand the causes of this phenomenon and develop diagnostics that might be applied to ameliorate its effects. We demonstrate here that two approaches for symbolizing the engine combustion measurements can provide useful probes for characterizing these instabilities. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Manufacturing stresses and strains in filament wound cylinders

NASA Technical Reports Server (NTRS)

Calius, E. P.; Kidron, M.; Lee, S. Y.; Springer, G. S.

1988-01-01

Tests were performed to verify a previously developed model for simulating the manufacturing process of filament wound cylinders. The axial and hoop strains were measured during cure inside a filament wound Fiberite T300/976 graphite-epoxy cylinder. The measured strains were compared to those computed by the model. Good agreements were found between the data and the model, indicating that the model is a useful representation of the process. For the conditions of the test, the manufacturing stresses inside the cylinder were also calculated using the model.

Levi-Civita cylinders with fractional angular deficit

NASA Astrophysics Data System (ADS)

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

2011-05-01

The angular deficit factor in the Levi-Civita vacuum metric has been parametrized using a Riemann-Liouville fractional integral. This introduces a new parameter into the general relativistic cylinder description, the fractional index α. When the fractional index is continued into the negative α region, new behavior is found in the Gott-Hiscock cylinder and in an Israel shell.

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.

Reordering transitions during annealing of block copolymer cylinder phases

DOE PAGES

Majewski, Pawel W.; Yager, Kevin G.

2015-10-06

While equilibrium block-copolymer morphologies are dictated by energy-minimization effects, the semi-ordered states observed experimentally often depend on the details of ordering pathways and kinetics. In this study, we explore reordering transitions in thin films of block-copolymer cylinder-forming polystyrene- block-poly(methyl methacrylate). We observe several transient states as films order towards horizontally-aligned cylinders. In particular, there is an early-stage reorganization from randomly-packed cylinders into hexagonally-packed vertically-aligned cylinders; followed by a reorientation transition from vertical to horizontal cylinder states. These transitions are thermally activated. The growth of horizontal grains within an otherwise vertical morphology proceeds anisotropically, resulting in anisotropic grains in the finalmore » horizontal state. The size, shape, and anisotropy of grains are influenced by ordering history; for instance, faster heating rates reduce grain anisotropy. These results help elucidate aspects of pathway-dependent ordering in block-copolymer thin films.« less

Adaptive individual-cylinder thermal state control using intake air heating for a GDCI engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roth, Gregory T.; Sellnau, Mark C.

A system for a multi-cylinder compression ignition engine includes a plurality of heaters, at least one heater per cylinder, with each heater configured to heat air introduced into a cylinder. Independent control of the heaters is provided on a cylinder-by-cylinder basis. A combustion parameter is determined for combustion in each cylinder of the engine, and control of the heater for that cylinder is based on the value of the combustion parameter for combustion in that cylinder. A method for influencing combustion in a multi-cylinder compression ignition engine, including determining a combustion parameter for combustion taking place in a cylinder ofmore » the engine and controlling a heater configured to heat air introduced into that cylinder, is also provided.« less

Curing A Large Composite Cylinder Without An Autoclave

NASA Technical Reports Server (NTRS)

Frazer, Robert E.

1992-01-01

Proposed technique provides application of heat and pressure to cure fiber-wound composite cylinder too large to fit in autoclave. Tube wound around cylinder applies pressure. Blanket distributes pressure. Pressure expels gas bubbles from material. Heat applied by conventional methods.

RESULTS FROM A DEMONSTRATION OF RF-BASED UF6 CYLINDER ACCOUNTING AND TRACKING SYSTEM INSTALLED AT A USEC FACILITY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pickett, Chris A; Kovacic, Donald N; Morgan, Jim

Approved industry-standard cylinders are used globally for storing and transporting uranium hexafluoride (UF{sub 6}) at uranium enrichment plants and processing facilities. To verify that no diversion or undeclared production of nuclear material involving UF{sub 6} cylinders at the facility has occurred, the International Atomic Energy Agency (IAEA) conducts periodic, labor-intensive physical inspections to validate facility records, cylinder identities, and cylinder weights. A reliable cylinder monitoring system that would improve overall inspector effectiveness would be a significant improvement to the current international safeguards inspection regime. Such a system could include real-time unattended monitoring of cylinder movements, situation-specific rules-based event detection algorithms,more » and the capability to integrate with other types of safeguards technologies. This type of system could provide timely detection of abnormal operational activities that may be used to ensure more appropriate and efficient responses by the IAEA. A system of this type can reduce the reliance on paper records and have the additional benefit of facilitating domestic safeguards at the facilities at which it is installed. A radio-frequency (RF)-based system designed to track uranium hexafluoride (UF{sub 6}) cylinders during processing operations was designed, assembled, and tested at the United States Enrichment Corporation (USEC) facility in Portsmouth, Ohio, to determine the operational feasibility and durability of RF technology. The overall objective of the effort was to validate the robustness of RF technology for potential use as a future international safeguards tool for tracking UF6 cylinders at uranium-processing facilities. The results to date indicate that RF tags represent a feasible technique for tracking UF{sub 6} cylinders in operating facilities. Additional work will be needed to improve the operational robustness of the tags for repeated autoclave

W-76 PBX 9501 cylinder tests

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hill, L.G.; Catanach, R.A.

1998-07-01

Five 1-inch diameter cylinder tests were fired in support of the W-76 high explosive surveillance program. Three of the tests used baseline material, and two used stockpile return material. The diagnostics were electrical pins to measure detonation velocity and a streak camera to measure wall motion. The data was analyzed for cylinder energy, Gurney energy, and detonation velocity. The results of all three measures were consistent for all five tests, to within the experimental accuracy.

Study of Multi-Cylinder Engine Manifolds

DTIC Science & Technology

1944-10-31

were developed so that mnifolds for any number of cylinders could be analyzed for max- I= zm volumetrie efficiency. Eletricaleebanioal analoCies can be...deceleration of the air& The vibrations are almot Identical to thse In single cylinder intake pipes. The mmi- a= volumetrie efficiency bould be...pipe 14 in. total volume 7- In- 3 area of pipew 0.86 in 2 Table I gives the actual and calculated speeds for peak volumetri efficiencies for a sIngle

Effects of cylinder Reynolds number on the turbulent horseshoe vortex system and near wake of a surface-mounted circular cylinder

NASA Astrophysics Data System (ADS)

Kirkil, Gokhan; Constantinescu, George

2015-07-01

The turbulent horseshoe vortex (HV) system and the near-wake flow past a circular cylinder mounted on a flat bed in an open channel are investigated based on the results of eddy-resolving simulations and supporting flow visualizations. Of particular interest are the changes in the mean flow and turbulence statistics within the HV region as the necklace vortices wrap around the cylinder's base and the variation of the mean flow and turbulence statistics in the near wake, in between the channel bed and the free surface. While it is well known that the drag crisis induces important changes in the flow past infinitely long circular cylinders, the changes are less understood and more complex for the case of flow past a surface-mounted cylinder. This is because even at very high cylinder Reynolds numbers, ReD, the flow regime remains subcritical in the vicinity of the bed surface due to the reduction of the incoming flow velocity within the bottom boundary layer. The paper provides a detailed discussion of the changes in the flow physics between cylinder Reynolds numbers at which the flow in the upstream part of the separated shear layers (SSLs) is laminar (ReD = 16 000, subcritical flow regime) and Reynolds numbers at which the transition occurs inside the attached boundary layers away from the bed and the flow within the SSLs is turbulent (ReD = 5 ∗ 105, supercritical flow regime). The changes between the two regimes in the dynamics and level of coherence of the large-scale coherent structures (necklace vortices, vortex tubes shed in the SSLs and roller vortices shed in the wake) and their capacity to induce high-magnitude bed friction velocities in the mean and instantaneous flow fields and to amplify the near-bed turbulence are analyzed. Being able to quantitatively and qualitatively describe these changes is critical to understand Reynolds-number-induced scale effects on sediment erosion mechanisms around cylinders mounted on a loose bed, which is a problem of

Development of advanced high temperature in-cylinder components and tribological systems for low heat rejection diesel engines, phase 1

NASA Astrophysics Data System (ADS)

Kroeger, C. A.; Larson, H. J.

1992-03-01

Analysis and concept design work completed in Phase 1 have identified a low heat rejection engine configuration with the potential to meet the Heavy Duty Transport Technology program specific fuel consumption goal of 152 g/kW-hr. The proposed engine configuration incorporates low heat rejection, in-cylinder components designed for operation at 24 MPa peak cylinder pressure. Water cooling is eliminated by selective oil cooling of the components. A high temperature lubricant will be required due to increased in-cylinder operating temperatures. A two-stage turbocharger air system with intercooling and aftercooling was selected to meet engine boost and BMEP requirements. A turbocompound turbine stage is incorporated for exhaust energy recovery. The concept engine cost was estimated to be 43 percent higher compared to a Caterpillar 3176 engine. The higher initial engine cost is predicted to be offset by reduced operating costs due the lower fuel consumption.

Development of advanced high temperature in-cylinder components and tribological systems for low heat rejection diesel engines, phase 1

NASA Technical Reports Server (NTRS)

Kroeger, C. A.; Larson, H. J.

1992-01-01

Analysis and concept design work completed in Phase 1 have identified a low heat rejection engine configuration with the potential to meet the Heavy Duty Transport Technology program specific fuel consumption goal of 152 g/kW-hr. The proposed engine configuration incorporates low heat rejection, in-cylinder components designed for operation at 24 MPa peak cylinder pressure. Water cooling is eliminated by selective oil cooling of the components. A high temperature lubricant will be required due to increased in-cylinder operating temperatures. A two-stage turbocharger air system with intercooling and aftercooling was selected to meet engine boost and BMEP requirements. A turbocompound turbine stage is incorporated for exhaust energy recovery. The concept engine cost was estimated to be 43 percent higher compared to a Caterpillar 3176 engine. The higher initial engine cost is predicted to be offset by reduced operating costs due the lower fuel consumption.

Calculation of the Thermal Loading of the Cylinder-Piston Group of the Automobile Engine

NASA Astrophysics Data System (ADS)

Barchenko, F. B.; Bakulin, V. N.

2017-05-01

We propose a mathematical model for calculating thermal loods of parts of the cylinder-piston group of the automobile engine operating under unstable conditions in its complete life cycle. Methods have been described for calculating the boundary conditions to determine the thermal state of the parts of the cylinder-piston group of such an engine with the use of theoretical formulas, empirical and semiempirical relations, and tabulated data. In modeling, we calculated the work of all systems of the engine (pumps, pipelines, heat exchangers) influencing directly or indirectly the thermal state of its cylinder-piston group. The nonstationary thermal state was calculated once in the operating cycle of the engine with the use of the cycle-averaged values of the local heat transfer coefficients and the resulting temperature of the medium. The personal computer counting time for one time step of a transport diesel engine of typical design with a number of units of the order of 500 was 5 s.

Non-invasive determination of external forces in vortex-pair-cylinder interactions

NASA Astrophysics Data System (ADS)

Hartmann, D.; Schröder, W.; Shashikanth, B. N.

2012-06-01

Expressions for the conserved linear and angular momenta of a dynamically coupled fluid + solid system are derived. Based on the knowledge of the flow velocity field, these expressions allow the determination of the external forces exerted on a body moving in the fluid such as, e.g., swimming fish. The verification of the derived conserved quantities is done numerically. The interaction of a vortex pair with a circular cylinder in various configurations of motions representing a generic test case for a dynamically coupled fluid + solid system is investigated in a weakly compressible Navier-Stokes setting using a Cartesian cut-cell method, i.e., the moving circular cylinder is represented by cut cells on a moving mesh. The objectives of this study are twofold. The first objective is to show the robustness of the derived expressions for the conserved linear and angular momenta with respect to bounded and discrete data sets. The second objective is to study the coupled dynamics of the vortex pair and a neutrally buoyant cylinder free to move in response to the fluid stresses exerted on its surface. A comparison of the vortex-body interaction with the case of a fixed circular cylinder evidences significant differences in the vortex dynamics. When the cylinder is fixed strong secondary vorticity is generated resulting in a repeating process between the primary vortex pair and the cylinder. In the neutrally buoyant cylinder case, a stable structure consisting of the primary vortex pair and secondary vorticity shear layers stays attached to the moving cylinder. In addition to these fundamental cases, the vortex-pair-cylinder interaction is studied for locomotion at constant speed and locomotion at constant thrust. It is shown that a similar vortex structure like in the neutrally buoyant cylinder case is obtained when the cylinder moves away from the approaching vortex pair at a constant speed smaller than the vortex pair translational velocity. Finally, the idealized

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.

Utilising flags to reduce drag around a short finite circular cylinder

NASA Astrophysics Data System (ADS)

Javadi, Kh.; Kiani, F.; Tahaye Abadi, M.

2018-03-01

This paper utilises flags to decrease the drag around a short finite circular cylinder. Wall-adapted large eddy simulation and two-way fluid-structure interaction methods were applied to resolve unsteady turbulent flow structure. The far-field Reynolds number of the current configuration based on the cylinder diameter was chosen to be 20,000. In addition, the length-to-diameter ratio of the cylinder was assumed to be L/D = 2 whereas the flexible flag had a width-to-diameter ratio of W/D = 1.5. The results were compared with the regular short finite circular cylinder and the rigid flagged cylinder in our previous work. The results indicate that utilising flags inside the near-wake region of the cylinder reduces the pressure drag. The physical mechanism of this drag reduction is presented.

Stratified spin-up in a sliced, square cylinder

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

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.more » 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)« less

Test and Analysis Correlation of a Large-Scale, Orthogrid-Stiffened Metallic Cylinder without Weld Lands

NASA Technical Reports Server (NTRS)

Rudd, Michelle T.; Hilburger, Mark W.; Lovejoy, Andrew E.; Lindell, Michael C.; Gardner, Nathaniel W.; Schultz, Marc R.

2018-01-01

The NASA Engineering Safety Center (NESC) Shell Buckling Knockdown Factor Project (SBKF) was established in 2007 by the NESC with the primary objective to develop analysis-based buckling design factors and guidelines for metallic and composite launch-vehicle structures.1 A secondary objective of the project is to advance technologies that have the potential to increase the structural efficiency of launch-vehicles. The SBKF Project has determined that weld-land stiffness discontinuities can significantly reduce the buckling load of a cylinder. In addition, the welding process can introduce localized geometric imperfections that can further exacerbate the inherent buckling imperfection sensitivity of the cylinder. Therefore, single-piece barrel fabrication technologies can improve structural efficiency by eliminating these weld-land issues. As part of this effort, SBKF partnered with the Advanced Materials and Processing Branch (AMPB) at NASA Langley Research Center (LaRC), the Mechanical and Fabrication Branch at NASA Marshall Space Flight Center (MSFC), and ATI Forged Products to design and fabricate an 8-ft-diameter orthogrid-stiffened seamless metallic cylinder. The cylinder was subjected to seven subcritical load sequences (load levels that are not intended to induce test article buckling or material failure) and one load sequence to failure. The purpose of this test effort was to demonstrate the potential benefits of building cylindrical structures with no weld lands using the flow-formed manufacturing process. This seamless barrel is the ninth 8-ft-diameter metallic barrel and the first single-piece metallic structure to be tested under this program.

49 CFR 180.205 - General requirements for requalification of specification cylinders.

Code of Federal Regulations, 2010 CFR

2010-10-01

... for steel and nickel cylinders (IBR, see § 171.7 of this subchapter); C-6.1 for seamless aluminum... neck using a steel stamp; (ii) For composite cylinders, securely affix to the cylinder a label with the...

49 CFR 180.205 - General requirements for requalification of specification cylinders.

Code of Federal Regulations, 2013 CFR

2013-10-01

... for steel and nickel cylinders (IBR, see § 171.7 of this subchapter); C-6.1 for seamless aluminum... neck using a steel stamp; (ii) For composite cylinders, securely affix to the cylinder a label with the...

49 CFR 180.205 - General requirements for requalification of specification cylinders.

Code of Federal Regulations, 2011 CFR

2011-10-01

... for steel and nickel cylinders (IBR, see § 171.7 of this subchapter); C-6.1 for seamless aluminum... neck using a steel stamp; (ii) For composite cylinders, securely affix to the cylinder a label with the...

49 CFR 180.205 - General requirements for requalification of specification cylinders.

Code of Federal Regulations, 2012 CFR

2012-10-01

... for steel and nickel cylinders (IBR, see § 171.7 of this subchapter); C-6.1 for seamless aluminum... neck using a steel stamp; (ii) For composite cylinders, securely affix to the cylinder a label with the...

Modal and Impact Dynamics Analysis of an Aluminum Cylinder

NASA Technical Reports Server (NTRS)

Lessard, Wendy B.

2002-01-01

This paper presents analyses for the modal characteristics and impact response of an all-aluminum cylinder. The analyses were performed in preparation for impact tests of the cylinder at The Impact Dynamics Research Facility (IDRF) at the NASA Langley Research Center. Mode shapes and frequencies were computed using NASTRAN and compared with existing experimental data to assess the overall accuracy of the mass and stiffness of the finite element model. A series of non-linear impact analyses were then performed using MSC Dytran in which the weight distribution on the floor and the impact velocity of the cylinder were varied. The effects of impact velocity and mass on the rebound and gross deformation of the cylinder were studied in this investigation.

Optimal viscous damping of vibrating porous cylinders

NASA Astrophysics Data System (ADS)

Jafari Kang, Saeed; Masoud, Hassan

2017-11-01

We theoretically study small-amplitude oscillations of permeable cylinders immersed in an unbounded fluid. Specifically, we examine the effects of permeability and oscillation frequency on the damping coefficient, which is proportional to the power required to sustain the vibrations. Cylinders of both circular and non-circular cross-sections undergoing transverse and rotational vibrations are considered. Our calculations indicate that the damping coefficient often varies non-monotonically with the permeability. Depending on the oscillation period, the maximum damping of a permeable cylinder can be many times greater than that of an otherwise impermeable one. This might seem counter-intuitive at first since generally the power it takes to steadily drag a permeable object through the fluid is less than the power needed to drive the steady motion of the same but impermeable object. However, the driving power (or damping coefficient) for oscillating bodies is determined by not only the amplitude of the cyclic fluid force experienced by them but also by the phase shift between the force and their periodic motion. An increase in the latter is responsible for excess damping coefficient of vibrating porous cylinders.

21 CFR 886.1840 - Simulatan (including crossed cylinder).

Code of Federal Regulations, 2010 CFR

2010-04-01

... of cylinder lenses that provides various equal plus and minus refractive strengths. The lenses are arranged so that the user can exchange the positions of plus and minus cylinder lenses of equal strengths... given object is clearly in focus, as the examiner uses different lenses). (b) Classification. Class I...

The flow dynamics behind a flexible finite cylinder as a flexible agitator

NASA Astrophysics Data System (ADS)

Yong, T. H.; Chan, H. B.; Dol, S. S.; Wee, S. K.; Kumar, P.

2017-06-01

This paper investigates the flow dynamics behind a flexible finite cylinder in a single-phase flow using a water tunnel. The cylinder was individually submerged in water at ReD = 4000, 6000 and 8000. The cylinder investigated has a AR = 10 and 16 and is made of EVA in order to achieve the lower stiffness for flexibility. A same AR of its aluminium rigid cylinder was investigated to serve as a benchmark to the flow dynamics behind a flexible cylinder. The results the downwash that hinders the transportation of vortices to the downstream was diminished. As a direct consequence of this phenomenon, the turbulence production has seen significant improvement for flexible finite cylinder.

JEL Cylinder is moved into Crawler Transporter No. 2

NASA Technical Reports Server (NTRS)

2002-01-01

KENNEDY SPACE CENTER, FLA. -- The final Jacking, Equalization and Leveling (JEL) cylinder is moved to Crawler Transporter No. 2 (CT-2) for installation. During recent routine maintenance inspections, cracks were found on four bearings in two JEL cylinders. Further eddy current inspections indicated that cracks were present on 15 bearings. There are 16 cylinders and 32 bearings per crawler. CT-2 was repaired in order to enable Atlantis' rollout for mission STS-112, scheduled for launch no earlier than Oct. 2.

A Balanced Diaphragm Type of Maximum Cylinder Pressure Indicator

NASA Technical Reports Server (NTRS)

Spanogle, J A; Collins, John H , Jr

1930-01-01

A balanced diaphragm type of maximum cylinder pressure indicator was designed to give results consistent with engine operating conditions. The apparatus consists of a pressure element, a source of controlled high pressure and a neon lamp circuit. The pressure element, which is very compact, permits location of the diaphragm within 1/8 inch of the combustion chamber walls without water cooling. The neon lamp circuit used for indicating contact between the diaphragm and support facilitates the use of the apparatus with multicylinder engines.

An Operator Perspective from a Facility Evaluation of an RFID-Based UF6 Cylinder Accounting and Tracking System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martyn, Rose; Fitzgerald, Peter; Stehle, Nicholas D

An operational field test of a Radio-Frequency Identification (RFID) system for tracking and accounting UF6 cylinders was conducted at the Global Nuclear Fuel Americas (GNF) fuel fabrication plant in 2009. The Cylinder Accountability and Tracking System (CATS) was designed and deployed by Oak Ridge National Laboratory (ORNL) and evaluated in cooperation with GNF. The system required that passive RFID be attached to several UF6 30B cylinders as they were received at the site; then the cylinders were tracked as they proceeded to interim storage, to processing in an autoclave, and eventually to disposition from the site. This CATS deployment alsomore » provided a direct integration of scale data from the site accountability scales. The integration of this information into the tracking data provided an attribute for additional safeguards for evaluation. The field test provided insight into the advantages and challenges of using RFID at an operating nuclear facility. The RFID system allowed operators to interact with the technology and demonstrated the survivability of the tags and reader equipment in the process environment. This paper will provide the operator perspective on utilizing RFID technology for locating cylinders within the facility, thereby tracking the cylinders for process and for Material Control & Accounting functions. The paper also will present the operator viewpoint on RFID implemented as an independent safeguards system.« less

Advanced engine management of individual cylinders for control of exhaust species

DOEpatents

Graves, Ronald L [Knoxville, TN; West, Brian H [Knoxville, TN; Huff, Shean P [Knoxville, TN; Parks, II, James E

2008-12-30

A method and system controls engine-out exhaust species of a combustion engine having a plurality of cylinders. The method typically includes various combinations of steps such as controlling combustion parameters in individual cylinders, grouping the individual cylinders into a lean set and a rich set of one or more cylinders, combusting the lean set in a lean combustion parameter condition having a lean air:fuel equivalence ratio, combusting the rich set in a rich combustion parameter condition having a rich air:fuel equivalence ratio, and adjusting the lean set and the rich set of one or more cylinders to generate net-lean combustion. The exhaust species may have elevated concentrations of hydrogen and oxygen.

76 FR 33023 - Safety Advisory; Unauthorized Marking of Compressed Gas Cylinders

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-07

... cylinders. The cylinders were neither marked nor certified by an authorized independent inspection agency... mark, the cylinder did not undergo the complete series of safety tests and inspections required by the... contents under pressure during normal transportation and use. Extensive property damage, serious personal...

76 FR 71124 - Safety Advisory: Unauthorized Marking of Compressed Gas Cylinders

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-16

... requalification company and properly marked. FOR FURTHER INFORMATION CONTACT: Morgan Welding and Supply, Mr... high pressure DOT cylinders. The evidence suggests that if a cylinder purchased from Morgan Welding and... cylinders from service and contact Morgan Welding and Supply, Albion, MI for further instructions. However...

Three-Dimensional, Laminar Flow Past a Short, Surface-Mounted Cylinder

NASA Astrophysics Data System (ADS)

Liakos, Anastasios; Malamataris, Nikolaos

2016-11-01

The topology and evolution of three-dimensional flow past a cylinder of slenderness ratio SR = 1 mounted in a wind tunnel is examined for 0 . 1 <= Re <= 325 (based on the diameter of the cylinder) where steady-state solutions have been obtained. Direct numerical simulations were computed using an in-house parallel finite element code. Results indicate that symmetry breaking occurs at Re = 1 , while the first prominent structure is a horseshoe vortex downstream from the cylinder. At Re = 150 , two foci are observed, indicating the formation of two tornadolike vortices downstream. Concurrently, another horseshoe vortex is formed upstream from the cylinder. For higher Reynolds numbers, the flow downstream is segmented to upper and lower parts, whereas the topology of the flow on the solid boundaries remains unaltered. Pressure distributions show that pressure, the key physical parameter in the flow, decreases everywhere except immediately upstream from the cylinder. In addition, creation of critical points from saddle-node-type bifurcations occur when the streamwise component of the pressure gradient changes sign. Finally, at Re = 325 , an additional horseshoe vorrtex is formed at the wake of the cylinder

Transient thermal stress problem for a circumferentially cracked hollow cylinder

NASA Technical Reports Server (NTRS)

Nied, H. F.; Erdogan, F.

1982-01-01

The transient thermal stress problem for a hollow elasticity cylinder containing an internal circumferential edge crack is considered. It is assumed that the problem is axisymmetric with regard to the crack geometry and the loading, and that the inertia effects are negligible. The problem is solved for a cylinder which is suddenly cooled from inside. First the transient temperature and stress distributions in an uncracked cylinder are calculated. By using the equal and opposite of this thermal stress as the crack surface traction in the isothermal cylinder the crack problem is then solved and the stress intensity factor is calculated. The numerical results are obtained as a function of the Fourier number tD/b(2) representing the time for various inner-to-outer radius ratios and relative crack depths, where D and b are respectively the coefficient of diffusivity and the outer radius of the cylinder.

Cylinder wakes in flowing soap films

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

46 CFR 95.16-20 - Extinguishing agent: Cylinder storage.

Code of Federal Regulations, 2014 CFR

2014-10-01

... cylinder storage room and the protected spaces must meet the insulation criteria for Class A-60, as defined... pneumatic heat actuator as well as a remote manual control. (c) The cylinder storage space must be properly...

46 CFR 95.16-20 - Extinguishing agent: Cylinder storage.

Code of Federal Regulations, 2012 CFR

2012-10-01

... cylinder storage room and the protected spaces must meet the insulation criteria for Class A-60, as defined... pneumatic heat actuator as well as a remote manual control. (c) The cylinder storage space must be properly...

46 CFR 95.16-20 - Extinguishing agent: Cylinder storage.

Code of Federal Regulations, 2013 CFR

2013-10-01

... cylinder storage room and the protected spaces must meet the insulation criteria for Class A-60, as defined... pneumatic heat actuator as well as a remote manual control. (c) The cylinder storage space must be properly...

JEL Cylinder is moved into Crawler Transporter No. 2

NASA Technical Reports Server (NTRS)

2002-01-01

KENNEDY SPACE CENTER, FLA. -- Workers help guide the final Jacking, Equalization and Leveling (JEL) cylinder into place on Crawler Transporter No. 2 (CT-2) for installation. During recent routine maintenance inspections, cracks were found on four bearings in two JEL cylinders. Further eddy current inspections indicated that cracks were present on 15 bearings. There are 16 cylinders and 32 bearings per crawler. CT-2 was repaired in order to enable Atlantis' rollout for mission STS-112, scheduled for launch no earlier than Oct. 2.

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

Results from a Field Trial of the Radio Frequency Based Cylinder Accountability and Tracking System at the Global Nuclear Fuel Americas Fuel Fabrication Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fitzgerald, Peter; Laughter, Mark D; Martyn, Rose

The Cylinder Accountability and Tracking System (CATS) is a tool designed for use by the International Atomic Energy Agency (IAEA) to improve overall inspector efficiency through real-time unattended monitoring of cylinder movements, site specific rules-based event detection, and the capability to integrate many types of monitoring technologies. The system is based on the tracking of cylinder movements using (radio frequency) RF tags, and the collection of data, such as accountability weights, that can be associated with the cylinders. This presentation will cover the installation and evaluation of the CATS at the Global Nuclear Fuels (GNF) fuel fabrication facility in Wilmington,more » NC. This system was installed to evaluate its safeguards applicability, operational durability under operating conditions, and overall performance. An overview of the system design and elements specific to the GNF deployment will be presented along with lessons learned from the installation process and results from the field trial.« less

Rolling motion of an elastic cylinder induced by elastic strain gradients

NASA Astrophysics Data System (ADS)

Chen, Lei; Chen, Shaohua

2014-10-01

Recent experiment shows that an elastic strain gradient field can be utilized to transport spherical particles on a stretchable substrate by rolling, inspired by which a generalized plane-strain Johnson-Kendall-Roberts model is developed in this paper in order to verify possible rolling of an elastic cylinder adhering on an elastic substrate subject to a strain gradient. With the help of contact mechanics, closed form solutions of interface tractions, stress intensity factors, and corresponding energy release rates in the plane-strain contact model are obtained, based on which a possible rolling motion of an elastic cylinder induced by strain gradients is found and the criterion for the initiation of rolling is established. The theoretical prediction is consistent well with the existing experimental observation. The result should be helpful for understanding biological transport mechanisms through muscle contractions and the design of transport systems with strain gradient.

Frictional properties of lubrication greases with the addition of nickel nanoparticles in pneumatic cylinder

NASA Astrophysics Data System (ADS)

Chang, Ho; Lan, Chou-Wei; Guo, Jia-Bin

2011-12-01

This paper studies the influence of addition of 100 nm diameter nickel nano-particles on the friction properties of synthetic grease (Li base, VG100) in pneumatic cylinder. The friction force test of pneumatic cylinder equipment measures the frictional force between seal and cylinder bore in pneumatic cylinders. The lubricants with addition of nickel nano-particles were used for lubricating the contact interface between seal and cylinder bore. The friction force test equipment employ a load cell force sensor to measure the friction force between seals and cylinder bores. Results obtained from experimental tests are compared to determine the friction force between seals and cylinder bore in pneumatic cylinders. The study leads to the conclusion that the addition of nickel nano-particles to synthetic grease results in a decrease in friction force between seals and cylinder bores in pneumatic cylinder. This tribological behavior is closely related to the deposition of nano-particles on the rubbing surfaces

Flow around a helically twisted elliptic cylinder

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Woojin; Lee, Jungil; Choi, Haecheon, E-mail: choi@snu.ac.kr

In the present study, we conduct unsteady three-dimensional simulations of flows around a helically twisted elliptic (HTE) cylinder at the Reynolds numbers of 100 and 3900, based on the free-stream velocity and square root of the product of the lengths of its major and minor axes. A parametric study is conducted for Re = 100 by varying the aspect ratio (AR) of the elliptic cross section and the helical spanwise wavelength (λ). Depending on the values of AR and λ, the flow in the wake contains the characteristic wavelengths of λ, 2λ, 6λ, or even longer than 60λ, showing amore » wide diversity of flows in the wake due to the shape change. The drag on the optimal (i.e., having lowest drag) HTE cylinder (AR = 1.3 and λ = 3.5d) is lower by 18% than that of the circular cylinder, and its lift fluctuations are zero owing to complete suppression of vortex shedding in the wake. This optimal HTE configuration reduces the drag by 23% for Re = 3900 where the wake is turbulent, showing that the HTE cylinder reduces the mean drag and lift fluctuations for both laminar and turbulent flows.« less

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.

The provision of clearances accuracy in piston - cylinder mating

NASA Astrophysics Data System (ADS)

Glukhov, V. I.; Shalay, V. V.

2017-08-01

The paper is aimed at increasing the quality of the pumping equipment in oil and gas industry. The main purpose of the study is to stabilize maximum values of productivity and durability of the pumping equipment based on the selective assembly of the cylinder-piston kinematic mating by optimization criterion. It is shown that the minimum clearance in the piston-cylinder mating is formed by maximum material dimensions. It is proved that maximum material dimensions are characterized by their own laws of distribution within the tolerance limits for the diameters of the cylinder internal mirror and the outer cylindrical surface of the piston. At that, their dispersion zones should be divided into size groups with a group tolerance equal to half the tolerance for the minimum clearance. The techniques for measuring the material dimensions - the smallest cylinder diameter and the largest piston diameter according to the envelope condition - are developed for sorting them into size groups. Reliable control of the dimensions precision ensures optimal minimum clearances of the piston-cylinder mating in all the size groups of the pumping equipment, necessary for increasing the equipment productivity and durability during the production, operation and repair processes.

Acoustic resonances in cylinder bundles oscillating in a compressibile fluid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, W.H.; Raptis, A.C.

1984-12-01

This paper deals with an analytical study on acoustic resonances of elastic oscillations of a group of parallel, circular, thin cylinders in an unbounded volume of barotropic, compressible, inviscid fluid. The perturbed motion of the fluid is assumed due entirely to the flexural oscillations of the cylinders. The motion of the fluid disturbances is first formulated in a three-dimensional wave form and then casted into a two-dimensional Helmholtz equation for the harmonic motion in time and in axial space. The acoustic motion in the fluid and the elastic motion in the cylinders are solved simultaneously. Acoustic resonances were approximately determinedmore » from the secular (eigenvalue) equation by the method of successive iteration with the use of digital computers for a given set of the fluid properties and the cylinders' geometry and properties. Effects of the flexural wavenumber and the configuration of and the spacing between the cylinders on the acoustic resonances were thoroughly investigated.« less

Cylinder stitching interferometry: with and without overlap regions

NASA Astrophysics Data System (ADS)

Peng, Junzheng; Chen, Dingfu; Yu, Yingjie

2017-06-01

Since the cylinder surface is closed and periodic in the azimuthal direction, existing stitching methods cannot be used to yield the 360° form map. To address this problem, this paper presents two methods for stitching interferometry of cylinder: one requires overlap regions, and the other does not need the overlap regions. For the former, we use the first order approximation of cylindrical coordinate transformation to build the stitching model. With it, the relative parameters between the adjacent sub-apertures can be calculated by the stitching model. For the latter, a set of orthogonal polynomials, termed Legendre Fourier (LF) polynomials, was developed. With these polynomials, individual sub-aperture data can be expanded as composition of inherent form of partial cylinder surface and additional misalignment parameters. Then the 360° form map can be acquired by simultaneously fitting all sub-aperture data with LF polynomials. Finally the two proposed methods are compared under various conditions. The merits and drawbacks of each stitching method are consequently revealed to provide suggestion in acquisition of 360° form map for a precision cylinder.

78 FR 42817 - Safety Advisory: Unauthorized Filling of Compressed Gas Cylinders

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-17

... transportation high pressure compressed gas cylinders without verifying that they met the appropriate safety... in turn alerted PHMSA of an incident on June 25, 2013, in which a high pressure DOT 3A 1800 cylinder... high pressure US DOT and special permit cylinders with compressed gases without verifying that they met...

Clean Air Program : cylinder issues associated with alternative fuels

DOT National Transportation Integrated Search

1999-01-01

A number of incidents of compressed natural gas (CNG) cylinder leaks have occurred while transit buses were either in service or at a bus maintenance facility. This study was initiated to determine the degree to which cylinder problems still exist in...

Fluid forces on two circular cylinders in crossflow

NASA Astrophysics Data System (ADS)

Jendrzejczyk, J. A.; Chen, S. S.

1986-07-01

Fluid excitation forces are measured in a water loop for two circular cylinders arranged in tandem and normal to flow. The Strouhal number and fluctuating drag and lift coefficients for both cylinders are presented for various spacings and incoming flow conditions. The results show the effects of Reynolds number, pitch ratio, and upstream turbulence on the fluid excitation forces.

Experimental study on a heavy-gas cylinder accelerated by cylindrical converging shock waves

NASA Astrophysics Data System (ADS)

Si, T.; Zhai, Z.; Luo, X.; Yang, J.

2014-01-01

The Richtmyer-Meshkov instability behavior of a heavy-gas cylinder accelerated by a cylindrical converging shock wave is studied experimentally. A curved wall profile is well-designed based on the shock dynamics theory [Phys. Fluids, 22: 041701 (2010)] with an incident planar shock Mach number of 1.2 and a converging angle of in a mm square cross-section shock tube. The cylinder mixed with the glycol droplets flows vertically through the test section and is illuminated horizontally by a laser sheet. The images obtained only one per run by an ICCD (intensified charge coupled device) combined with a pulsed Nd:YAG laser are first presented and the complete evolution process of the cylinder is then captured in a single test shot by a high-speed video camera combined with a high-power continuous laser. In this way, both the developments of the first counter-rotating vortex pair and the second counter-rotating vortex pair with an opposite rotating direction from the first one are observed. The experimental results indicate that the phenomena induced by the converging shock wave and the reflected shock formed from the center of convergence are distinct from those found in the planar shock case.

Effects of cylinder Reynolds number on the turbulent horseshoe vortex system and near wake of a surface-mounted circular cylinder

NASA Astrophysics Data System (ADS)

Kirkil, Gokhan; Constantinescu, George

2014-11-01

The turbulent horseshoe vortex (HV) system and the near-wake flow past a circular cylinder mounted on a flat bed in an open channel are investigated based on results of eddy-resolving simulations and supporting flow visualizations. Of particular interest are the changes in the mean flow and turbulence statistics within the HV region as the necklace vortices wrap around the cylinder's base and the variation of the mean flow and turbulence statistics in the near wake, in between the channel bed and the free surface. While it is well known that the drag crisis induces important changes in the flow past infinitely-long circular cylinders, the changes are less understood and more complex for the case of flow past a surface-mounted cylinder. A detailed discussion of the changes in the flow physics between cylinder Reynolds numbers at which the flow in the upstream part of the separated shear layers (SSLs) is laminar (Re = 16,000, subcritical flow regime) and Reynolds numbers at which transition occurs inside the attached boundary layers away from the bed and the flow within the SSLs is turbulent (Re = 500,000, supercritical flow regime). The changes between the two regimes in the dynamics and level of coherence of the large-scale coherent structures (necklace vortices, vortex tubes shed in the SSLs and roller vortices shed in the wake) and their capacity to induce high-magnitude bed friction velocities in the mean and instantaneous flow fields and to amplify the near-bed turbulence are analyzed.

Lattice Boltzmann simulation of viscoelastic flow past a confined free rotating cylinder

NASA Astrophysics Data System (ADS)

Xia, Yi; Zhang, Peijie; Lin, Jianzhong; Ku, Xiaoke; Nie, Deming

2018-05-01

To study the dynamics of rigid body immersed in viscoelastic fluid, an Oldroyd-B fluid flow past an eccentrically situated, free rotating cylinder in a two-dimensional (2D) channel is simulated by a novel lattice Boltzmann method. Two distribution functions are employed, one of which is aimed to solve Navier-Stokes equation and the other to the constitutive equation, respectively. The unified interpolation bounce-back scheme is adopted to treat the moving curved boundary of cylinder, and the novel Galilean invariant momentum exchange method is utilized to obtain the hydrodynamic force and torque exerted on the cylinder. Results show that the center-fixed cylinder rotates inversely in the direction where a cylinder immersed in Newtonian fluid do, which generates a centerline-oriented lift force according to Magnus effect. The cylinder’s eccentricity, flow inertia, fluid elasticity and viscosity would affect the rotation of cylinder in different ways. The cylinder rotates more rapidly when located farther away from the centerline, and slows down when it is too close to the wall. The rotation frequency decreases with increasing Reynolds number, and larger rotation frequency responds to larger Weissenberg number and smaller viscosity ratio, indicating that the fluid elasticity and low solvent viscosity accelerates the flow-induced rotation of cylinder.

The Federal Cylinder Project: A Guide to Field Cylinder Collections in Federal Agencies. Volume 2, Northeastern Indian Catalog and Southeastern Indian Catalog.

ERIC Educational Resources Information Center

Gray, Judith A., Ed.; And Others

Two catalogs inventory field-recorded wax cylinders which document the music and language of Indian tribes in northeastern and southeastern United States from 1890-1930. The Northeastern Indian Catalog contains entries for 738 cylinders comprising 16 music and spoken word collections from the Chippewa, Fox, Iroquois, Kickapoo, Menominee,…

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.

Dynamic Fracture Simulations of Explosively Loaded Cylinders

DOE Office of Scientific and Technical Information (OSTI.GOV)

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.

Piston cylinder cell for high pressure ultrasonic pulse echo measurements.

PubMed

Kepa, M W; Ridley, C J; Kamenev, K V; Huxley, A D

2016-08-01

Ultrasonic techniques such as pulse echo, vibrating reed, or resonant ultrasound spectroscopy are powerful probes not only for studying elasticity but also for investigating electronic and magnetic properties. Here, we report on the design of a high pressure ultrasonic pulse echo apparatus, based on a piston cylinder cell, with a simplified electronic setup that operates with a single coaxial cable and requires sample lengths of mm only. The design allows simultaneous measurements of ultrasonic velocities and attenuation coefficients up to a pressure of 1.5 GPa. We illustrate the performance of the cell by probing the phase diagram of a single crystal of the ferromagnetic superconductor UGe2.

Piston cylinder cell for high pressure ultrasonic pulse echo measurements

NASA Astrophysics Data System (ADS)

Kepa, M. W.; Ridley, C. J.; Kamenev, K. V.; Huxley, A. D.

2016-08-01

Ultrasonic techniques such as pulse echo, vibrating reed, or resonant ultrasound spectroscopy are powerful probes not only for studying elasticity but also for investigating electronic and magnetic properties. Here, we report on the design of a high pressure ultrasonic pulse echo apparatus, based on a piston cylinder cell, with a simplified electronic setup that operates with a single coaxial cable and requires sample lengths of mm only. The design allows simultaneous measurements of ultrasonic velocities and attenuation coefficients up to a pressure of 1.5 GPa. We illustrate the performance of the cell by probing the phase diagram of a single crystal of the ferromagnetic superconductor UGe2.

Flow of wormlike micellar solutions around confined microfluidic cylinders.

PubMed

Zhao, Ya; Shen, Amy Q; Haward, Simon J

2016-10-26

Wormlike micellar (WLM) solutions are frequently used in enhanced oil and gas recovery applications in porous rock beds where complex microscopic geometries result in mixed flow kinematics with strong shear and extensional components. Experiments with WLM solutions through model microfluidic porous media have revealed a variety of complex flow phenomena, including the formation of stable gel-like structures known as a Flow-Induced Structured Phase (FISP), which undoubtedly play an important role in applications of WLM fluids, but are still poorly understood. A first step in understanding flows of WLM fluids through porous media can be made by examining the flow around a single micro-scale cylinder aligned on the flow axis. Here we study flow behavior of an aqueous WLM solution consisting of cationic surfactant cetyltrimethylammonium bromide (CTAB) and a stable hydrotropic salt 3-hydroxy naphthalene-2-carboxylate (SHNC) in microfluidic devices with three different cylinder blockage ratios, β. We observe a rich sequence of flow instabilities depending on β as the Weissenberg number (Wi) is increased to large values while the Reynolds number (Re) remains low. Instabilities upstream of the cylinder are associated with high stresses in fluid that accelerates into the narrow gap between the cylinder and the channel wall; vortex growth upstream is reminiscent of that seen in microfluidic contraction geometries. Instability downstream of the cylinder is associated with stresses generated at the trailing stagnation point and the resulting flow modification in the wake, coupled with the onset of time-dependent flow upstream and the asymmetric division of flow around the cylinder.

The One-Pot Directed Assembly of Cylinder-Forming Block Copolymer on Adjacent Chemical Patterns for Bimodal Patterning.

PubMed

Chang, Tzu-Hsuan; Xiong, Shisheng; Liu, Chi-Chun; Liu, Dong; Nealey, Paul F; Ma, Zhenqiang

2017-09-01

The direct self-assembly of cylinder-forming poly(styrene-block-methyl-methacrylate) (PS-b-PMMA) block copolymer is successfully assembled into two orientations, according to the underlying guiding pattern in different areas. Lying-down and perpendicular cylinders are formed, respectively, depending on the design of chemical pattern: sparse line/space pattern or hexagonal dot array. The first chemical pattern composed of prepatterned cross-linked polystyrene (XPS) line/space structure has a period (L S ) equal to twice the intercylinder period of the block copolymer (L 0 ). The PS-b-PMMA thin film on the prepared chemical template after thermal annealing forms a lying-down cylinder morphology when the width of the PS strips is less than the width of PS block in the PS-b-PMMA block copolymer. The morphology is only applicable at the discrete thickness of the PS-b-PMMA film. In addition to forming the lying-down cylinders directly on the XPS guiding pattern, the cylinder-forming block copolymer can also be assembled in a perpendicular way on the second guiding pattern (the hexagonal dot array). The block copolymer films are registered into two orientations in a single directed self-assembly process. The features of the assembled patterns are successfully transferred down to the silicon oxide substrate. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optimization of In-Cylinder Pressure Filter for Engine Research

DTIC Science & Technology

2017-06-01

ARL-TR-8034 ● JUN 2017 US Army Research Laboratory Optimization of In-Cylinder Pressure Filter for Engine Research by Kenneth...Laboratory Optimization of In-Cylinder Pressure Filter for Engine Research by Kenneth S Kim, Michael T Szedlmayer, Kurt M Kruger, and Chol-Bum M...

Variable high gradient permanent magnet quadrupole (QUAPEVA)

NASA Astrophysics Data System (ADS)

Marteau, F.; Ghaith, A.; N'Gotta, P.; Benabderrahmane, C.; Valléau, M.; Kitegi, C.; Loulergue, A.; Vétéran, J.; Sebdaoui, M.; André, T.; Le Bec, G.; Chavanne, J.; Vallerand, C.; Oumbarek, D.; Cosson, O.; Forest, F.; Jivkov, P.; Lancelot, J. L.; Couprie, M. E.

2017-12-01

Different applications such as laser plasma acceleration, colliders, and diffraction limited light sources require high gradient quadrupoles, with strength that can reach up to 200 T/m for a typical 10 mm bore diameter. We present here a permanent magnet based quadrupole (so-called QUAPEVA) composed of a Halbach ring and surrounded by four permanent magnet cylinders. Its design including magnetic simulation modeling enabling us to reach 201 T/m with a gradient variability of 45% and mechanical issues are reported. Magnetic measurements of seven systems of different lengths are presented and confirmed the theoretical expectations. The variation of the magnetic center while changing the gradient strength is ±10 μm. A triplet of QUAPEVA magnets is used to efficiently focus a beam with large energy spread and high divergence that is generated by a Laser Plasma Acceleration source for a free electron laser demonstration and has enabled us to perform beam based alignment and control the dispersion of the beam.

System and method of cylinder deactivation for optimal engine torque-speed map operation

DOEpatents

Sujan, Vivek A; Frazier, Timothy R; Follen, Kenneth; Moon, Suk-Min

2014-11-11

This disclosure provides a system and method for determining cylinder deactivation in a vehicle engine to optimize fuel consumption while providing the desired or demanded power. In one aspect, data indicative of terrain variation is utilized in determining a vehicle target operating state. An optimal active cylinder distribution and corresponding fueling is determined from a recommendation from a supervisory agent monitoring the operating state of the vehicle of a subset of the total number of cylinders, and a determination as to which number of cylinders provides the optimal fuel consumption. Once the optimal cylinder number is determined, a transmission gear shift recommendation is provided in view of the determined active cylinder distribution and target operating state.

Numerical study of axial turbulent flow over long cylinders

NASA Technical Reports Server (NTRS)

Neves, J. C.; Moin, P.; Moser, R. D.

1991-01-01

The effects of transverse curvature are investigated by means of direct numerical simulations of turbulent axial flow over cylinders. Two cases of Reynolds number of about 3400 and layer-thickness-to-cylinder-radius ratios of 5 and 11 were simulated. All essential turbulence scales were resolved in both calculations, and a large number of turbulence statistics were computed. The results are compared with the plane channel results of Kim et al. (1987) and with experiments. With transverse curvature the skin friction coefficient increases and the turbulence statistics, when scaled with wall units, are lower than in the plane channel. The momentum equation provides a scaling that collapses the cylinder statistics, and allows the results to be interpreted in light of the plane channel flow. The azimuthal and radial length scales of the structures in the flow are of the order of the cylinder diameter. Boomerang-shaped structures with large spanwise length scales were observed in the flow.

Tokamak blanket design study: FY 78 summary report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1979-06-01

A tokamak blanket cylindrical module concept was designed, developed, and analyzed after review of several existing generic concepts. The design is based on use of state-of-the-art structural materials (20% cold worked type 316 stainless steel), lithium as the breeding material, and pressurized helium as the coolant. The module design consists of nested concentric cylinders and features direct wall cooling by flowing helium between the outer (first wall) cylinder and the inner lithium containing cylinder. Each cylinder is capable of withstanding full coolant pressure for enhanced reliability. Results show that stainless steel is a viable material for a first wall subjectedmore » to 4 MW/m/sup 2/ neutron and 1 MW/m/sup 2/ particle heat flux. A lifetime analysis showed that the first wall design meets the goal of operating at 20 minute cycles with 95% duty for 10/sup 5/ cycles. The design is attractive for further development, and additional work and supporting experiments are identified to reduce analytical uncertainties and enhance the design reliability.« less

Modeling of composite hydrogen storage cylinders using finite element analysis

DOT National Transportation Integrated Search

2008-02-01

Pressurized hydrogen storage cylinders are critical components of hydrogen transportation systems. Composite cylinders have pressure/thermal relief devices that are activated in case of an emergency. The difficulty in accurately analyzing the behavio...

State of practice for concrete cylinder match curing and effect of test cylinder size.

DOT National Transportation Integrated Search

2014-01-01

The prestressed concrete element industry is interested in exploring the application of different types of matchcuring : technologies and in using 4 x 8-in. (100 x 200-mm) cylinders to measure concrete compressive strength : instead of the standard 6...

Impact fragmentation of polyurethane and polypropylene cylinder

NASA Astrophysics Data System (ADS)

Kishimura, Hiroaki; Noguchi, Daisuke; Preechasupanya, Worrayut; Matsumoto, Hitoshi

2013-11-01

The impact fragmentation of a bulk polyurethane elastomer (PU) and polypropylene (PP) cylinder have been investigated using a Cu plate projectile launched by a propellant gun at a velocity of 0.53-1.4 km/s. A projectile drills into a PU sample and forms a cavity in the sample. A small number of tiny fragments are formed. When the projectile smashes in at 1.4 km/s, the PU cylinder bursts and PU fragments form. On the other hand, a brittle fracture occurs on the PP cylinder. The mass of fragments from the PU sample generated at a lower impact velocity is distributed in the lognormal form, whereas the mass of fragments from the PU sample generated by a 1.4 km/s impact follows a power-law distribution. The fragment mass distribution of the PP sample generated at a lower impact velocity obeys the power-law form, whereas that generated at a higher impact velocity follows the lognormal form.

Electric line source illumination of a chiral cylinder placed in another chiral background medium

NASA Astrophysics Data System (ADS)

Aslam, M.; Saleem, A.; Awan, Z. A.

2018-05-01

An electric line source illumination of a chiral cylinder embedded in a chiral background medium is considered. The field expressions inside and outside of a chiral cylinder have been derived using the wave field decomposition approach. The effects of various chiral cylinders, chiral background media and source locations upon the scattering gain pattern have been investigated. It is observed that the chiral background reduces the backward scattering gain as compared to the free space background for a dielectric cylinder. It is also studied that by moving a line source away from a cylinder reduces the backward scattering gain for a chiral cylinder placed in a chiral background under some specific conditions. A unique phenomenon of reduced scattering gain has been observed at a specific observation angle for a chiral cylinder placed in a chiral background having an electric line source location of unity free space wavelength. An isotropic scattering gain pattern is observed for a chiral nihility background provided that if cylinder is chiral or chiral nihility type. It is also observed that this isotropic behaviour is independent of background and cylinder chirality.

Method of making superconducting cylinders for flux detectors

DOEpatents

Goodkind, J.M.; Stolfa, D.L.

1971-07-06

A method of making superconducting cylinders of the ''weak link'' type is provided. The method allows the weak link to be made much smaller than was heretofore possible, thereby greatly increasing sensitivity and operating temperature range when the cylinder is used in a flux detector. The resistance of the weak link is monitored continuously as metal is removed from the link by electrochemical action.

Energy Loss, Velocity Distribution, and Temperature Distribution for a Baffled Cylinder Model

NASA Technical Reports Server (NTRS)

Brevoort, Maurice J

1937-01-01

A study has been made of the important principles involved in the operation of a baffle for an engine cylinder and shows that cooling can be improved by 20 percent by using a correctly designed baffle. Such a gain is as effective as a 65 percent increase in pressure drop across the standard baffle, which had a 1/4 inch clearance between baffle and fin tips.

Rotation of an immersed cylinder sliding near a thin elastic coating

NASA Astrophysics Data System (ADS)

Rallabandi, Bhargav; Saintyves, Baudouin; Jules, Theo; Salez, Thomas; Schönecker, Clarissa; Mahadevan, L.; Stone, Howard A.

2017-07-01

It is known that an object translating parallel to a soft wall in a viscous fluid produces hydrodynamic stresses that deform the wall, which in turn results in a lift force on the object. Recent experiments with cylinders sliding under gravity near a soft incline, which confirmed theoretical arguments for the lift force, also reported an unexplained steady-state rotation of the cylinders [B. Saintyves et al., Proc. Natl. Acad. Sci. USA 113, 5847 (2016), 10.1073/pnas.1525462113]. Motivated by these observations, we show, in the lubrication limit, that an infinite cylinder that translates in a viscous fluid parallel to a soft wall at constant speed and separation distance must also rotate in order to remain free of torque. Using the Lorentz reciprocal theorem, we show analytically that for small deformations of the elastic layer, the angular velocity of the cylinder scales with the cube of the sliding speed. These predictions are confirmed numerically. We then apply the theory to the gravity-driven motion of a cylinder near a soft incline and find qualitative agreement with the experimental observations, namely, that a softer elastic layer results in a greater angular speed of the cylinder.

Transient thermal stress problem for a circumferentially cracked hollow cylinder

NASA Technical Reports Server (NTRS)

Nied, H. F.; Erdogan, F.

1983-01-01

The paper is concerned with the transient thermal stress problem for a long hollow circular cylinder containing an internal axisymmetric circumferential edge crack that is suddenly cooled from inside. It is assumed that the transient thermal stress problem is quasi-static, i.e., the inertial effects are negligible. Also, all thermoelastic coupling effects and the possible temperature dependence of the thermoelastic constants are neglected. The problem is considered in two parts. The first part is the evaluation of transient thermal stresses in an uncracked cylinder; the second part is the isothermal perturbation problem for the cracked cylinder in which the crack surface tractions, equal and opposite to the thermal stresses obtained from the first problem, are the only external loads. The superposition of the two solutions gives results for the cracked cylinder.

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.

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

Elastic Cheerios effect: Self-assembly of cylinders on a soft solid

NASA Astrophysics Data System (ADS)

Chakrabarti, Aditi; Ryan, Louis; Chaudhury, Manoj K.; Mahadevan, L.

2015-12-01

A rigid cylinder placed on a soft gel deforms its surface. When multiple cylinders are placed on the surface, they interact with each other via the topography of the deformed gel which serves as an energy landscape; as they move, the landscape changes which in turn changes their interaction. We use a combination of experiments, simple scaling estimates and numerical simulations to study the self-assembly of cylinders in this elastic analog of the "Cheerios Effect", which describes capillary interactions on a fluid interface. Our results show that the effective two-body interaction can be well described by an exponential attraction potential as a result of which the dynamics also show an exponential behavior with respect to the separation distance. When many cylinders are placed on the gel, the cylinders cluster together if they are not too far apart; otherwise their motion gets elastically arrested.

Using kinematic reduction for studying grasping postures. An application to power and precision grasp of cylinders.

PubMed

Jarque-Bou, N; Gracia-Ibáñez, V; Sancho-Bru, J L; Vergara, M; Pérez-González, A; Andrés, F J

2016-09-01

The kinematic analysis of human grasping is challenging because of the high number of degrees of freedom involved. The use of principal component and factorial analyses is proposed in the present study to reduce the hand kinematics dimensionality in the analysis of posture for ergonomic purposes, allowing for a comprehensive study without losing accuracy while also enabling velocity and acceleration analyses to be performed. A laboratory study was designed to analyse the effect of weight and diameter in the grasping posture for cylinders. This study measured the hand posture from six subjects when transporting cylinders of different weights and diameters with precision and power grasps. The hand posture was measured using a Vicon(®) motion-tracking system, and the principal component analysis was applied to reduce the kinematics dimensionality. Different ANOVAs were performed on the reduced kinematic variables to check the effect of weight and diameter of the cylinders, as well as that of the subject. The results show that the original twenty-three degrees of freedom of the hand were reduced to five, which were identified as digit arching, closeness, palmar arching, finger adduction and thumb opposition. Both cylinder diameter and weight significantly affected the precision grasping posture: diameter affects closeness, palmar arching and opposition, while weight affects digit arching, palmar arching and closeness. The power-grasping posture was mainly affected by the cylinder diameter, through digit arching, closeness and opposition. The grasping posture was largely affected by the subject factor and this effect couldn't be attributed only to hand size. In conclusion, this kinematic reduction allowed identifying the effect of the diameter and weight of the cylinders in a comprehensive way, being diameter more important than weight. Copyright © 2016 Elsevier Ltd. All rights reserved.

Current-voltage characteristics of dc corona discharges in air between coaxial cylinders

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, Yuesheng, E-mail: yueshengzheng@fzu.edu.cn; Zhang, Bo, E-mail: shizbcn@tsinghua.edu.cn; He, Jinliang, E-mail: hejl@tsinghua.edu.cn

This paper presents the experimental measurement and numerical analysis of the current-voltage characteristics of dc corona discharges in air between coaxial cylinders. The current-voltage characteristics for both positive and negative corona discharges were measured within a specially designed corona cage. Then the measured results were fitted by different empirical formulae and analyzed by the fluid model. The current-voltage characteristics between coaxial cylinders can be expressed as I = C(U − U{sub 0}){sup m}, where m is within the range 1.5–2.0, which is similar to the point-plane electrode system. The ionization region has no significant effect on the current-voltage characteristic under a low corona current,more » while it will affect the distribution for the negative corona under a high corona current. The surface onset fields and ion mobilities were emphatically discussed.« less

Pressure fluctuations on the surface of a cylinder in uniform flow

NASA Technical Reports Server (NTRS)

Ayoub, A.; Karamcheti, K.

1976-01-01

The problem of determining the pressure fluctuations induced on the surface of a cylinder by the fluctuating wake behind it is formulated. A formal solution relating the unsteady surface pressure field to the velocity field in the wake is derived and used to obtain general results independent of cylinder shape and Reynolds number. The case of the circular cylinder is then examined in detail.

Damage tolerance and arrest characteristics of pressurized graphite/epoxy tape cylinders

NASA Technical Reports Server (NTRS)

Ranniger, Claudia U.; Lagace, Paul A.; Graves, Michael J.

1993-01-01

An investigation of the damage tolerance and damage arrest characteristics of internally-pressurized graphite/epoxy tape cylinders with axial notches was conducted. An existing failure prediction methodology, developed and verified for quasi-isotropic graphite/epoxy fabric cylinders, was investigated for applicability to general tape layups. In addition, the effect of external circumferential stiffening bands on the direction of fracture path propagation and possible damage arrest was examined. Quasi-isotropic (90/0/plus or minus 45)s and structurally anisotropic (plus or minus 45/0)s and (plus or minus 45/90)s coupons and cylinders were constructed from AS4/3501-6 graphite/epoxy tape. Notched and unnotched coupons were tested in tension and the data correlated using the equation of Mar and Lin. Cylinders with through-thickness axial slits were pressurized to failure achieving a far-field two-to-one biaxial stress state. Experimental failure pressures of the (90/0/plus or minus 45)s cylinders agreed with predicted values for all cases but the specimen with the smallest slit. However, the failure pressures of the structurally anisotropic cylinders, (plus or minus 45/0)s and (plus or minus 45/90)s, were above the values predicted utilizing the predictive methodology in all cases. Possible factors neglected by the predictive methodology include structural coupling in the laminates and axial loading of the cylindrical specimens. Furthermore, applicability of the predictive methodology depends on the similarity of initial fracture modes in the coupon specimens and the cylinder specimens of the same laminate type. The existence of splitting which may be exacerbated by the axial loading in the cylinders, shows that this condition is not always met. The circumferential stiffeners were generally able to redirect fracture propagation from longitudinal to circumferential. A quantitative assessment for stiffener effectiveness in containing the fracture, based on cylinder

76 FR 38697 - High Pressure Steel Cylinders From China

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-01

... Pressure Steel Cylinders From China Determinations On the basis of the record \\1\\ developed in the subject... imports from China of high pressure steel cylinders, provided for in subheading 7311.00.00 of the... than fair value (LTFV) and subsidized by the Government of China. \\1\\ The record is defined in sec. 207...

Coupled vibration of isotropic metal hollow cylinders with large geometrical dimensions

NASA Astrophysics Data System (ADS)

Lin, Shuyu

2007-08-01

In this paper, the coupled vibration of isotropic metal hollow cylinders with large geometrical dimensions is studied by using an approximate analytic method. According to this method, when the equivalent mechanical coupling coefficient that is defined as the stress ratio is introduced, the coupled vibration of a metal hollow cylinder is reduced to two equivalent one-dimensional vibrations, one is an equivalent longitudinal extensional vibration in the height direction of the cylinder, and the other is an equivalent plane radial vibration in the radius direction. These two equivalent vibrations are coupled to each other by the equivalent mechanical coupling coefficient. The resonance frequency equation of metal hollow cylinders in coupled vibration is derived and longitudinal and radial resonance frequencies are computed. For comparison, the resonance frequencies of the hollow cylinders are also computed by using numerical method. The analysis shows that the results from these two methods are in a good agreement with each other.

Viscous Effects on Wave Forces on A Submerged Horizontal Circular Cylinder

NASA Astrophysics Data System (ADS)

Teng, Bin; Mao, Hong-Fei; Lu, Lin

2018-06-01

Numerical simulations are carried out for wave action on a submerged horizontal circular cylinder by means of a viscous fluid model, and it is focused on the examination of the discrepancies between the viscous fluid results and the potential flow solutions. It is found that the lift force resulted from rotational flow on the circular cylinder is always in anti-phase with the inertia force and induces the discrepancies between the results. The influence factors on the magnitude of the lift force, especially the correlation between the stagnation-point position and the wave amplitude, and the effect of the vortex shedding are investigated by further examination on the flow fields around the cylinder. The viscous numerical calculations at different wave frequencies showed that the wave frequency has also significant influence on the wave forces. Under higher frequency and larger amplitude wave action, vortex shedding from the circular cylinder will appear and influence the wave forces on the cylinder substantially.

Piston cylinder cell for high pressure ultrasonic pulse echo measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kepa, M. W., E-mail: mkepa@staffmail.ed.ac.uk; Huxley, A. D.; Ridley, C. J.

2016-08-15

Ultrasonic techniques such as pulse echo, vibrating reed, or resonant ultrasound spectroscopy are powerful probes not only for studying elasticity but also for investigating electronic and magnetic properties. Here, we report on the design of a high pressure ultrasonic pulse echo apparatus, based on a piston cylinder cell, with a simplified electronic setup that operates with a single coaxial cable and requires sample lengths of mm only. The design allows simultaneous measurements of ultrasonic velocities and attenuation coefficients up to a pressure of 1.5 GPa. We illustrate the performance of the cell by probing the phase diagram of a singlemore » crystal of the ferromagnetic superconductor UGe{sub 2}.« less

104. Photocopied August 1978. CYLINDER USED IN THE ERECTION OF ...

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

104. Photocopied August 1978. CYLINDER USED IN THE ERECTION OF THE INCLINED BUTTRESSES FOR POWER HOUSE REINFORCEMENT IN 1916. AN AIR LOCK WAS PLACED ON TOP OF THE CYLINDER: THE LOWER PORTION OF THE VERTICAL ELEMENT RESTED ON THE POWER HOUSE FOUNDATION APRON: THE INCLINED ELEMENT WAS CUT LEVEL WITH THE RIVER BED. THE INCLINED PORTION OF THE CYLINDER CONTAINED THE SHIELD USED TO BEGIN THE ERECTION OF THE SEGMENTED INCLINED CAST IRON BUTTRESSES. (764) - Michigan Lake Superior Power Company, Portage Street, Sault Ste. Marie, Chippewa County, MI

Asymmetric vortex pair in the wake of a circular cylinder

NASA Astrophysics Data System (ADS)

Iosilevskii, G.; Seginer, A.

1994-10-01

Stationary configurations of two asymmetric point vortices in the wake of an infinite circular cylinder, spinning or not about its axis, are analytically investigated using an ideal fluid approximation. Four different vortex configurations (patterns) in the wake of a spinning cylinder are found in the case when vortex asymmetry is weak; each configuration is associated with a certain direction of the Magnus force. The qualitative relation between a pattern and a direction of the Magnus force is in agreement with experimental data. Also obtained are asymmetrical vortex configurations in the wake of a nonspinning cylinder.

How many oxygen cylinders do you need to take on transport? A nomogram for cylinder size and duration

PubMed Central

Lutman, D; Petros, A J

2006-01-01

When undertaking patient retrieval, it is important to take adequate supplies of oxygen to ensure patient safety. Oxygen can be delivered via a flowmeter into a facemask or used to drive pneumatic ventilators. Given the lack of space in the back of an ambulance or helicopter, the numbers of cylinders that can be taken is limited, hence the number needed to complete the journey must be carefully calculated prior to embarking. We have produced nomograms to predict how many oxygen cylinders will be consumed during a given journey when using either a flowmeter or a commonly used transport ventilator. PMID:16921085

How many oxygen cylinders do you need to take on transport? A nomogram for cylinder size and duration.

PubMed

Lutman, D; Petros, A J

2006-09-01

When undertaking patient retrieval, it is important to take adequate supplies of oxygen to ensure patient safety. Oxygen can be delivered via a flowmeter into a facemask or used to drive pneumatic ventilators. Given the lack of space in the back of an ambulance or helicopter, the numbers of cylinders that can be taken is limited, hence the number needed to complete the journey must be carefully calculated prior to embarking. We have produced nomograms to predict how many oxygen cylinders will be consumed during a given journey when using either a flowmeter or a commonly used transport ventilator.

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.

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.

Vortex shedding noise of a cylinder with hairy flaps

NASA Astrophysics Data System (ADS)

Kamps, Laura; Geyer, Thomas F.; Sarradj, Ennes; Brücker, Christoph

2017-02-01

This study describes the modification of acoustic noise emitted from cylinders in a stationary subsonic flow for a cylinder equipped with flexible hairy flaps at the aft part as a passive way to manipulate the flow and acoustics. The study was motivated by the results from previous water tunnel measurements, which demonstrated that hairy flaps can modify the shedding cycle behind the cylinder and can reduce the wake deficit. In the present study, wind tunnel experiments were conducted on such a modified cylinder and the results were compared to the reference case of a plain cylinder. The acoustic spectrum was measured using two microphones while simultaneously recording the flap motion. To further examine the flow structures in the downstream vicinity of the cylinder, constant temperature anemometry measurements as well as flow visualizations were also performed. The results show that, above a certain Reynolds number, the hairy flaps lead to a jump in the vortex shedding frequency. This phenomenon is similarly observed in the water flow experiments as a jump in the non-dimensional Strouhal number that is related to the change of the shedding cycle. This jump appears to be coupled to a resonant excitation of the flaps. The specific Reynolds number at which the jump occurs is higher in the present case, which is attributed to the lower added mass in air as compared with the one in water. The flow visualizations confirmed that such action of the flaps lead to a more slender elongated shape of the time-averaged separation bubble. In addition, the hairy flaps induce a noticeable reduction of the tonal noise as well as broadband noise as long as the flaps do not touch each other.

Actuator placement for active sound and vibration control of cylinders

NASA Technical Reports Server (NTRS)

Kincaid, Rex K.

1995-01-01

Active structural acoustic control is a method in which the control inputs (used to reduce interior noise) are applied directly to a vibrating structural acoustic system. The control concept modeled in this work is the application of in-plane force inputs to piezoceramic patches bonded to the wall of a vibrating cylinder. The cylinder is excited by an exterior noise source -- an acoustic monopole -- located near the outside of the cylinder wall. The goal is to determine the force inputs and sites for the piezoelectric actuators so that (1) the interior noise is effectively damped; (2) the level of vibration of the cylinder shell is not increased; and (3) the power requirements needed to drive the actuators are not excessive. We studied external monopole excitations at two frequencies. A cylinder resonance of 100 Hz, where the interior acoustic field is driven in multiple, off-resonance cylinder cavity modes, and a cylinder resonance of 200 Hz are characterized by both near and off-resonance cylinder vibration modes which couple effectively with a single, dominant, low-order acoustic cavity mode at resonance. Previous work has focused almost exclusively on meeting objective (1) and solving a complex least-squares problem to arrive at an optimal force vector for a given set of actuator sites. In addition, it has been noted that when the cavity mode couples with cylinder vibration modes (our 200 Hz case) control spillover may occur in higher order cylinder shell vibrational modes. How to determine the best set of actuator sites to meet objectives (1)-(3) is the main contribution of our research effort. The selection of the best set of actuator sites from a set of potential sites is done via two metaheuristics -- simulated annealing and tabu search. Each of these metaheuristics partitions the set of potential actuator sites into two disjoint sets: those that are selected to control the noise (on) and those that are not (off). Next, each metaheuristic attempts to

Flow past an axially aligned spinning cylinder: Experimental Study

NASA Astrophysics Data System (ADS)

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

2017-11-01

Experimental investigation of flow past a spinning cylinder is presented in the context of its application and relevance to flow past projectiles. A subsonic wind tunnel is used to perform experiments on the flow past a spinning cylinder that is mounted on a forward sting and oriented such that its axis of rotation is aligned with the mean flow. The experiments cover a Reynolds number of range of up to 45000 and rotation numbers of up to 2 (based on cylinder diameter). Time-averaged mean flow and turbulence profiles in the wake flow are presented with and without spin along with comparison to published experimental data. Funded in part by the U. S. Army ARDEC, Picatinny Arsenal, NJ.

Stress intensity factors in a reinforced thick-walled cylinder

NASA Technical Reports Server (NTRS)

Tang, R.; Erdogan, F.

1984-01-01

An elastic thick-walled cylinder containing a radial crack is considered. It is assumed that the cylinder is reinforced by an elastic membrane on its inner surface. The model is intended to simulate pressure vessels with cladding. The formulation of the problem is reduced to a singular integral equation. Various special cases including that of a crack terminating at the cylinder-reinforcement interface are investigated and numerical examples are given. Results indicate that in the case of the crack touching the interface the crack surface displacement derivative is finite and consequently the stress state around the corresponding crack tip is bounded; and generally, for realistic values of the stiffness parameter, the effect of the reinforcement is not very significant.

Filament winding cylinders. II - Validation of the process model

NASA Technical Reports Server (NTRS)

Calius, Emilio P.; Lee, Soo-Yong; Springer, George S.

1990-01-01

Analytical and experimental studies were performed to validate the model developed by Lee and Springer for simulating the manufacturing process of filament wound composite cylinders. First, results calculated by the Lee-Springer model were compared to results of the Calius-Springer thin cylinder model. Second, temperatures and strains calculated by the Lee-Springer model were compared to data. The data used in these comparisons were generated during the course of this investigation with cylinders made of Hercules IM-6G/HBRF-55 and Fiberite T-300/976 graphite-epoxy tows. Good agreement was found between the calculated and measured stresses and strains, indicating that the model is a useful representation of the winding and curing processes.

Turbine endwall two-cylinder program. [wind tunnel and water tunnel investigation of three dimensional separation of fluid flow

NASA Technical Reports Server (NTRS)

Langston, L. S.

1980-01-01

Progress is reported in an effort to study the three dimensional separation of fluid flow around two isolated cylinders mounted on an endwall. The design and performance of a hydrogen bubble generator for water tunnel tests to determine bulk flow properties and to measure main stream velocity and boundary layer thickness are described. Although the water tunnel tests are behind schedule because of inlet distortion problems, tests are far enough along to indicate cylinder spacing, wall effects and low Reynolds number behavior, all of which impacted wind tunnel model design. The construction, assembly, and operation of the wind tunnel and the check out of its characteristics are described. An off-body potential flow program was adapted to calculate normal streams streamwise pressure gradients at the saddle point locations.

Cylinder expansion test and gas gun experiment comparison

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harrier, Danielle

This is a summer internship presentation by the Hydro Working Group at Los Alamos National Laboratory (LANL) and goes into detail about their cylinder expansion test and gas gun experiment comparison. Specifically, the gas gun experiment is detailed along with applications, the cylinder expansion test is detailed along with applications, there is a comparison of the methods with pros and cons and limitations listed, the summer project is detailed, and future work is talked about.

Evolution of In-Cylinder Diesel Engine Soot and Emission Characteristics Investigated with Online Aerosol Mass Spectrometry.

PubMed

Malmborg, V B; Eriksson, A C; Shen, M; Nilsson, P; Gallo, Y; Waldheim, B; Martinsson, J; Andersson, Ö; Pagels, J

2017-02-07

To design diesel engines with low environmental impact, it is important to link health and climate-relevant soot (black carbon) emission characteristics to specific combustion conditions. The in-cylinder evolution of soot properties over the combustion cycle and as a function of exhaust gas recirculation (EGR) was investigated in a modern heavy-duty diesel engine. A novel combination of a fast gas-sampling valve and a soot particle aerosol mass spectrometer (SP-AMS) enabled online measurements of the in-cylinder soot chemistry. The results show that EGR reduced the soot formation rate. However, the late cycle soot oxidation rate (soot removal) was reduced even more, and the net effect was increased soot emissions. EGR resulted in an accumulation of polycyclic aromatic hydrocarbons (PAHs) during combustion, and led to increased PAH emissions. We show that mass spectral and optical signatures of the in-cylinder soot and associated low volatility organics change dramatically from the soot formation dominated phase to the soot oxidation dominated phase. These signatures include a class of fullerene carbon clusters that we hypothesize represent less graphitized, C 5 -containing fullerenic (high tortuosity or curved) soot nanostructures arising from decreased combustion temperatures and increased premixing of air and fuel with EGR. Altered soot properties are of key importance when designing emission control strategies such as diesel particulate filters and when introducing novel biofuels.

Piston Bowl Optimization for RCCI Combustion in a Light-Duty Multi-Cylinder Engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hanson, Reed M; Curran, Scott; Wagner, Robert M

2012-01-01

Reactivity Controlled Compression Ignition (RCCI) is an engine combustion strategy that that produces low NO{sub x} and PM emissions with high thermal efficiency. Previous RCCI research has been investigated in single-cylinder heavy-duty engines. The current study investigates RCCI operation in a light-duty multi-cylinder engine at 3 operating points. These operating points were chosen to cover a range of conditions seen in the US EPA light-duty FTP test. The operating points were chosen by the Ad Hoc working group to simulate operation in the FTP test. The fueling strategy for the engine experiments consisted of in-cylinder fuel blending using port fuel-injectionmore » (PFI) of gasoline and early-cycle, direct-injection (DI) of diesel fuel. At these 3 points, the stock engine configuration is compared to operation with both the original equipment manufacturer (OEM) and custom machined pistons designed for RCCI operation. The pistons were designed with assistance from the KIVA 3V computational fluid dynamics (CFD) code. By using a genetic algorithm optimization, in conjunction with KIVA, the piston bowl profile was optimized for dedicated RCCI operation to reduce unburned fuel emissions and piston bowl surface area. By reducing these parameters, the thermal efficiency of the engine was improved while maintaining low NOx and PM emissions. Results show that with the new piston bowl profile and an optimized injection schedule, RCCI brake thermal efficiency was increased from 37%, with the stock EURO IV configuration, to 40% at the 2,600 rev/min, 6.9 bar BMEP condition, and NOx and PM emissions targets were met without the need for exhaust after-treatment.« less

Gas-lubricated seal for sealing between a piston and a cylinder wall

DOEpatents

Hoult, David P.

1985-01-01

A piston-cylinder seal uses gas for a lubricant and has a runner supported on a gapless structure and placed in the space between the piston and the cylinder wall. The runner is deformed elastically under the influence of the operating pressures to follow and compensate for variations in the piston-cylinder fit and maintain a seal.

Gas-lubricated seal for sealing between a piston and a cylinder wall

DOEpatents

Hoult, D.P.

1985-09-10

A piston-cylinder seal uses gas for a lubricant and has a runner supported on a gapless structure and placed in the space between the piston and the cylinder wall. The runner is deformed elastically under the influence of the operating pressures to follow and compensate for variations in the piston-cylinder fit and maintain a seal. 4 figs.

Mobile Robot Localization by Remote Viewing of a Colored Cylinder

NASA Technical Reports Server (NTRS)

Volpe, R.; Litwin, T.; Matthies, L.

1995-01-01

A system was developed for the Mars Pathfinder rover in which the rover checks its position by viewing the angle back to a colored cylinder with different colors for different angles. The rover determines distance by the apparent size of the cylinder.

Performance of Several Combustion Chambers Designed for Aircraft Oil Engines

NASA Technical Reports Server (NTRS)

Joachim, William F; Kemper, Carlton

1928-01-01

Several investigations have been made on single-cylinder test engines to determine the performance characteristics of four types of combustion chambers designed for aircraft oil engines. Two of the combustion chambers studied were bulb-type precombustion chambers, the connecting orifice of one having been designed to produce high turbulence by tangential air flow in both the precombustion chamber and the cylinder. The other two were integral combustion chambers, one being dome-shaped and the other pent-roof shaped. The injection systems used included cam and eccentric driven fuel pumps, and diaphragm and spring-loaded fuel-injection valves. A diaphragm type maximum cylinder pressure indicator was used in part of these investigations with which the cylinder pressures were controlled to definite valves. The performance of the engines when equipped with each of the combustion chambers is discussed. The best performance for the tests reported was obtained with a bulb-type combustion chamber designed to give a high degree of turbulence within the bulb and cylinder. (author)

Effect of location in an array on heat transfer to a cylinder in crossflow

NASA Technical Reports Server (NTRS)

Simoneau, R. J.; Vanfossen, G. J., Jr.

1982-01-01

An experiment was conducted to measure the heat transfer from a heated cylinder in crossflow in an array of circular cylinders. All cylinders had a length-to-diameter ratio of 3.0. Both in-line and staggered array patterns were studied. The cylinders were spaced 2.67 diameters apart center-to-center in both the axial and transverse directions to the flow. The row containing the heated cylinder remained in a fixed position in the channel and the relative location of this row within the array was changed by adding up to five upstream rows. The working fluid was nitrogen gas at pressures from 100 to 600 kPa. The Reynolds number ranged based on cylinder diameter and average unobstructed channel velocity was from 5,000 to 125,000. Turbulence intensity: profiles were measured for each case at a point one half space upstream of the row containing the heated cylinder. The basis of comparison for all the heat transfer data was the single row with the heated cylinder. For the in-line cases the addition of a single row of cylinders upstream of the row containing the heated cylinder increased the heat transfer by an average of 50 percent above the base case. Adding up to five more rows caused no increase or decrease in heat transfer. Adding rows in the staggered array cases resulted in average increases in heat transfer of 21, 64, 58, 46, and 46 percent for one to five upstream rows, respectively.

Piezoelectric actuator models for active sound and vibration control of cylinders

NASA Technical Reports Server (NTRS)

Lester, Harold C.; Lefebvre, Sylvie

1993-01-01

Analytical models for piezoelectric actuators, adapted from flat plate concepts, are developed for noise and vibration control applications associated with vibrating circular cylinders. The loadings applied to the cylinder by the piezoelectric actuators for the bending and in-plane force models are approximated by line moment and line force distributions, respectively, acting on the perimeter of the actuator patch area. Coupling between the cylinder and interior acoustic cavity is examined by studying the modal spectra, particularly for the low-order cylinder modes that couple efficiently with the cavity at low frequencies. Within the scope of this study, the in-plane force model produced a more favorable distribution of low-order modes, necessary for efficient interior noise control, than did the bending model.

Stress Intensity Factors for Part-Through Surface Cracks in Hollow Cylinders

NASA Technical Reports Server (NTRS)

Mettu, Sambi R.; Raju, Ivatury S.; Forman, Royce G.

1992-01-01

Flaws resulting from improper welding and forging are usually modeled as cracks in flat plates, hollow cylinders or spheres. The stress intensity factor solutions for these crack cases are of great practical interest. This report describes some recent efforts at improving the stress intensity factor solutions for cracks in such geometries with emphasis on hollow cylinders. Specifically, two crack configurations for cylinders are documented. One is that of a surface crack in an axial plane and the other is a part-through thumb-nail crack in a circumferential plane. The case of a part-through surface crack in flat plates is used as a limiting case for very thin cylinders. A combination of the two cases for cylinders is used to derive a relation for the case of a surface crack in a sphere. Solutions were sought which cover the entire range of the geometrical parameters such as cylinder thickness, crack aspect ratio and crack depth. Both the internal and external position of the cracks are considered for cylinders and spheres. The finite element method was employed to obtain the basic solutions. Power-law form of loading was applied in the case of flat plates and axial cracks in cylinders and uniform tension and bending loads were applied in the case of circumferential (thumb-nail) cracks in cylinders. In the case of axial cracks, the results for tensile and bending loads were used as reference solutions in a weight function scheme so that the stress intensity factors could be computed for arbitrary stress gradients in the thickness direction. For circumferential cracks, since the crack front is not straight, the above technique could not be used. Hence for this case, only the tension and bending solutions are available at this time. The stress intensity factors from the finite element method were tabulated so that results for various geometric parameters such as crack depth-to-thickness ratio (a/t), crack aspect ratio (a/c) and internal radius-to-thickness ratio (R

Implant abutment deformation during prosthetic cylinder screw tightening: an in vitro study.

PubMed

Neto, Rafael Tobias Moretti; Moura, Marcio Silva; Souza, Edson Antonio Capello; Rubo, José Henrique

2009-01-01

Nonpassive fit frameworks are believed to lead to implant overload and consequently loss of osseointegration. This is one of the most commonly reported failures of implant prostheses. In an ideal situation of passive fit, when torque is applied to bring the abutment-cylinder interface together some amount of deformation can be expected, and it should be homogeneous along the periphery of the abutment. The aim of this study was to verify the amount of abutment deformation that can be expected when a free-standing cylinder is screwed into place. This could give insight into what should be accepted as passive fit. Strain gauges were bonded to the sides of five standard abutments that had machined palladium-silver cylinders or cobalt-chromium cast cylinders screwed into place. Measurements were taken to verify the deformation at each site. Values of abutment deformation after abutment screw tightening ranged from -127.70 to -590.27 microepsilon. The deformation recorded for palladium-silver prosthetic cylinder tightening ranged from 56.905 to -381.50 microepsilon (mean: 173.298 microepsilon) and from -5.62638 to -383.86 microepsilon (mean: 200.474 microepsilon) for cobalt-chromium cylinders. There was no statistically significant difference among the two groups. Both abutment screw tightening and prosthetic cylinder screw tightening result in abutment deformation, which is compressive most of the time.

Structural design criteria for filament-wound composite shells

NASA Technical Reports Server (NTRS)

Hahn, H. T.; Jensen, D. W.; Claus, S. J.; Pai, S. P.; Hipp, P. A.

1994-01-01

Advanced composite cylinders, manufactured by filament winding, provide a cost effective solution to many present structural applications; however, the compressive performance of filament-wound cylinders is lower than comparable shells fabricated from unidirectional tape. The objective of this study was to determine the cause of this reduction in thin filament-wound cylinders by relating the manufacturing procedures to the quality of the cylinder and to its compressive performance. The experiments on cylinder buckling were complemented by eigenvalue buckling analysis using a detailed geometric model in a finite element analysis. The applicability of classical buckling analyses was also investigated as a design tool.

49 CFR 178.39 - Specification 3BN seamless nickel cylinders.

Code of Federal Regulations, 2013 CFR

2013-10-01

... manufactured using equipment and processes adequate to ensure that each cylinder produced conforms to the.... A reasonably smooth and uniform surface finish is required. Cylinders closed in by spinning process... plugs, etc.) for those openings. Threads conforming to the following are required on openings: (1...

49 CFR 178.39 - Specification 3BN seamless nickel cylinders.

Code of Federal Regulations, 2014 CFR

2014-10-01

... manufactured using equipment and processes adequate to ensure that each cylinder produced conforms to the.... A reasonably smooth and uniform surface finish is required. Cylinders closed in by spinning process... plugs, etc.) for those openings. Threads conforming to the following are required on openings: (1...

49 CFR 178.39 - Specification 3BN seamless nickel cylinders.

Code of Federal Regulations, 2012 CFR

2012-10-01

... manufactured using equipment and processes adequate to ensure that each cylinder produced conforms to the.... A reasonably smooth and uniform surface finish is required. Cylinders closed in by spinning process... plugs, etc.) for those openings. Threads conforming to the following are required on openings: (1...

Speed control with end cushion for high speed air cylinder

DOEpatents

Stevens, Wayne W.; Solbrig, Charles W.

1991-01-01

A high speed air cylinder in which the longitudinal movement of the piston within the air cylinder tube is controlled by pressurizing the air cylinder tube on the accelerating side of the piston and releasing pressure at a controlled rate on the decelerating side of the piston. The invention also includes a method for determining the pressure required on both the accelerating and decelerating sides of the piston to move the piston with a given load through a predetermined distance at the desired velocity, bringing the piston to rest safely without piston bounce at the end of its complete stroke.

Rotating Cylinder Treatment System Demonstration

EPA Science Inventory

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

49 CFR 178.44 - Specification 3HT seamless steel cylinders for aircraft use.

Code of Federal Regulations, 2013 CFR

2013-10-01

... cylinder. (d) Manufacture. Cylinders must be manufactured using equipment and processes adequate to ensure.... (h) Openings in cylinders and connections (valves, fuse plugs, etc.) for those openings. Threads conforming to the following are required on openings: (1) Threads must be clean cut, even, without cracks...

49 CFR 178.44 - Specification 3HT seamless steel cylinders for aircraft use.

Code of Federal Regulations, 2012 CFR

2012-10-01

... cylinder. (d) Manufacture. Cylinders must be manufactured using equipment and processes adequate to ensure.... (h) Openings in cylinders and connections (valves, fuse plugs, etc.) for those openings. Threads conforming to the following are required on openings: (1) Threads must be clean cut, even, without cracks...

49 CFR 178.44 - Specification 3HT seamless steel cylinders for aircraft use.

Code of Federal Regulations, 2014 CFR

2014-10-01

... cylinder. (d) Manufacture. Cylinders must be manufactured using equipment and processes adequate to ensure.... (h) Openings in cylinders and connections (valves, fuse plugs, etc.) for those openings. Threads conforming to the following are required on openings: (1) Threads must be clean cut, even, without cracks...

Two Dimensional Steady State Eddy Current Analysis of a Spinning Conducting Cylinder

DTIC Science & Technology

2017-03-09

generate electromagnetic effects which can disrupt the electronic components contained inside the round. Finite element analyses were conducted to...which affect the magnetic field inside the cylinder were analyzed by varying the angular velocities and the electromagnetic properties (permeability and...the magnetic field distribution inside the cylinder was affected by angular velocity and the electromagnetic properties of the cylinder. 15

Development of Flexible Pneumatic Cylinder with Built-in Flexible Linear Encoder and Flexible Bending Sensor

NASA Astrophysics Data System (ADS)

Akagi, Tetsuya; Dohta, Shujiro; Matsushita, Hisashi; Fukuhara, Akimasa

The purpose of this study is to develop a lightweight and intelligent soft actuator which can be safely attached to the human body. A novel flexible pneumatic cylinder that can be used even if it is deformed by external force had been proposed. The cylinder can realize both pushing and pulling motions even if the cylinder bends. In this paper, a flexible pneumatic cylinder with a built-in flexible linear encoder is proposed and tested. The encoder can detect the cylinder displacement even if the cylinder bends. In the next step, to realize an intelligent flexible cylinder, it is essential to recognize the angle of deflection of the cylinder to estimate the direction of the external force. Therefore, a flexible bending sensor that can measure the directional angle by attaching it to the end of the cylinder is also proposed and tested. The tested bending sensor also consists of four inexpensive photo-reflectors set on the circumferential surface to the cylinder tube every 90 degrees from the center of the tube. By measuring the distance between the photo reflector and the surface of the tube at each point, the bending directional angle of the cylinder can be obtained. A low cost measuring system using a micro-computer incorporating a programmed Up/Down counter to measure the displacement of the cylinder is also developed. As a result, it was confirmed that the measuring accuracy of the bending directional angle was good, less than 0.7 degrees as a standard deviation.

Aspects of CO2 laser engraving of printing cylinders.

PubMed

Atanasov, P A; Maeno, K; Manolov, V P

1999-03-20

Results of the experimental and theoretical investigations of CO(2) laser-engraved cylinders are presented. The processed surfaces of test samples are examined by a phase-stepping laser interferometer, digital microscope, and computer-controlled profilometer. Fourier analysis is made on the patterns parallel to the axis of the laser-scribed test ceramic cylinders. The problem of the visually observed banding is discussed.

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.

Effect of plasma actuator and splitter plate on drag coefficient of a circular cylinder

NASA Astrophysics Data System (ADS)

Akbıyık, Hürrem; Erkan Akansu, Yahya; Yavuz, Hakan; Ertuğrul Bay, Ahmet

2016-03-01

In this paper, an experimental study on flow control around a circular cylinder with splitter plate and plasma actuator is investigated. The study is performed in wind tunnel for Reynolds numbers at 4000 and 8000. The wake region of circular cylinder with a splitter plate is analyzed at different angles between 0 and 180 degrees. In this the study, not only plasma actuators are activated but also splitter plate is placed behind the cylinder. A couple electrodes are mounted on circular cylinder at ±90 degrees. Also, flow visualization is achieved by using smoke wire method. Drag coefficient of the circular cylinder with splitter plate and the plasma actuator are obtained for different angles and compared with the plain circular cylinder. While attack angle is 0 degree, drag coefficient is decreased about 20% by using the splitter plate behind the circular cylinder. However, when the plasma actuators are activated, the improvement of the drag reduction is measured to be 50%.

Shear-induced autorotation of freely rotatable cylinder in a channel flow at moderate Reynolds number

NASA Astrophysics Data System (ADS)

Xia, Yi; Lin, Jianzhong; Ku, Xiaoke; Chan, Tatleung

2018-04-01

Flow past a center-pinned freely rotatable cylinder asymmetrically confined in a two-dimensional channel is simulated with the lattice Boltzmann method for a range of Reynolds number 0.1 ≤ Re ≤ 200, eccentricity ratio 0/8 ≤ ɛ ≤ 7/8, and blockage ratio 0.1 ≤ β ≤ 0.5. It is found that the inertia tends to facilitate the anomalous clockwise rotation of the cylinder. As the eccentricity ratio increases, the cylinder rotates faster in the counterclockwise direction and then slows down at a range of Re < 10. At a range of Re > 40, there exists an anomalous clockwise rotation for the cylinder at a low eccentricity ratio and the domain where the cylinder rotates anomalously becomes larger with the increase in the Reynolds number. In a channel with a higher blockage ratio, the rotation of the cylinder is more sensitive to the change of cylinder lateral position, and the separatrix at which the cylinder remains a state of rest moves upward generally. The cylinder is more likely to rotate counterclockwise and the rotating velocity is larger. At a lower blockage ratio, the anomalous clockwise rotation is more likely to occur, and the largest rotating velocity occurs when the blockage ratio is equal to 0.3. The mechanism of distinct rotational behavior of the cylinder is attributed to the transformation of distribution of shear stress which is resulted from the variation of pressure drop, the shift of maximum or minimum pressure zones along the upper and lower semi-cylinder surface, and the movement of stagnant point and separate point. Finally, the effects of the cylinder rotation on the flow structure and hydrodynamic force exerted on the cylinder surface are analyzed as well.

Online Condition Monitoring of Gripper Cylinder in TBM Based on EMD Method

NASA Astrophysics Data System (ADS)

Li, Lin; Tao, Jian-Feng; Yu, Hai-Dong; Huang, Yi-Xiang; Liu, Cheng-Liang

2017-11-01

The gripper cylinder that provides braced force for Tunnel Boring Machine (TBM) might fail due to severe vibration when the TBM excavates in the tunnel. Early fault diagnosis of the gripper cylinder is important for the safety and efficiency of the whole tunneling project. In this paper, an online condition monitoring system based on the Empirical Mode Decomposition (EMD) method is established for fault diagnosis of the gripper cylinder while TBM is working. Firstly, the lumped mass parameter model of the gripper cylinder is established considering the influence of the variable stiffness at the rock interface, the equivalent stiffness of the oil, the seals, and the copper guide sleeve. The dynamic performance of the gripper cylinder is investigated to provide basis for its health condition evaluation. Then, the EMD method is applied to identify the characteristic frequencies of the gripper cylinder for fault diagnosis and a field test is used to verify the accuracy of the EMD method for detection of the characteristic frequencies. Furthermore, the contact stiffness at the interface between the barrel and the rod is calculated with Hertz theory and the relationship between the natural frequency and the stiffness varying with the health condition of the cylinder is simulated based on the dynamic model. The simulation shows that the characteristic frequencies decrease with the increasing clearance between the barrel and the rod, thus the defects could be indicated by monitoring the natural frequency. Finally, a health condition management system of the gripper cylinder based on the vibration signal and the EMD method is established, which could ensure the safety of TBM.

Hydrodynamic force characteristics of slender cylinders in the splash zone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haritos, N.; Daliri, M.R.

1995-12-31

This paper presents results from a pilot experimental program of research being performed on segmented vertical surface-piercing cylinders in the Department of Civil and Environmental Engineering at The University of Melbourne. The primary aim of this investigation is to determine the influence of the splash zone on the hydrodynamic force characteristics of such cylinders to wave loading in the Morison regime. This influence is assessed from a comparison of the observed force characteristics of instrumented segments located in the splash zone with the corresponding results obtained from similarly instrumented segments located in the fully submerged zone and from those obtainedmore » for the cylinder as a whole via measurements of the cylinder tip restraint force. Results to hand for uni-directional regular waves suggest that there appears to be a mild frequency dependence in the inertia force coefficient in the splash zone which only marginally exceeds the corresponding values observed for a submerged segment immediately below this zone.« less

Algebraic Approximations to Extinction from Randomly Oriented Circular and Elliptical Cylinders

DTIC Science & Technology

1995-06-01

amplitude (Ref. 3). The strict limit of validity of the formula is therefore the region where ( n - 1) < < 1. The cylinder is in effect treated as a slit... cylinders , l¢1x = 2Im -1lx << 1. This occurs since what we have been calling an edge effect is in fact the field distortion around the boundaries of the...ALGERBRAIC APPROXIMATIONS TO EXTINCTION FROM RANDOMLY ORIENTED CIRCULAR AND ELLIPTICAL CYLINDERS system Number: Patron Number: Requester: Notes

Effect of the cross sectional aspect ratio on the flow past a twisted cylinder

NASA Astrophysics Data System (ADS)

Jung, Jae Hwan; Yoon, Hyun Sik

2013-11-01

The cross-flow around twisted cylinders of cross sectional aspect ratio (A/B) from 1 to 2.25 is investigated at a subcritical Reynolds number (Re) of 3000 using large eddy simulation (LES). The flow past a corresponding smooth and wavy cylinder is also calculated for comparison and validation against experimental data. The effect of twisted surface assessed in terms of the mean drag and root-mean-square (RMS) value of fluctuating lift. The shear layer of the twisted cylinder covering the recirculation region is more elongated than those of the smooth and the wavy cylinder. Successively, vortex shedding of the twisted cylinder is considerably suppressed, compared with those of the smooth and the wavy cylinder. The maximum drag reduction of up to 13% compared with a smooth cylinder is obtained at a certain cross sectional aspect ratio. The fluctuating lift coefficient of the twisted cylinder is also significantly suppressed. We found that the cross sectional cross sectional aspect ratio (A/B) plays an essential role in determining the vortical structures behind the twisted cylinder which has a significant effect on the reduction of the fluctuating lift and suppression of flow-induced vibration. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) through GCRC-SOP (No. 2011-0030013).

Pulsatile blood flow and oxygen transport past a circular cylinder.

PubMed

Zierenberg, Jennifer R; Fujioka, Hideki; Hirschl, Ronald B; Bartlett, Robert H; Grotberg, James B

2007-04-01

The fundamental study of blood flow past a circular cylinder filled with an oxygen source is investigated as a building block for an artificial lung. The Casson constitutive equation is used to describe the shear-thinning and yield stress properties of blood. The presence of hemoglobin is also considered. Far from the cylinder, a pulsatile blood flow in the x direction is prescribed, represented by a time periodic (sinusoidal) component superimposed on a steady velocity. The dimensionless parameters of interest for the characterization of the flow and transport are the steady Reynolds number (Re), Womersley parameter (alpha), pulsation amplitude (A), and the Schmidt number (Sc). The Hill equation is used to describe the saturation curve of hemoglobin with oxygen. Two different feed-gas mixtures were considered: pure O(2) and air. The flow and concentration fields were computed for Re=5, 10, and 40, 0< or =A< or =0.75, alpha=0.25, 0.4, and Schmidt number, Sc=1000. The Casson fluid properties result in reduced recirculations (when present) downstream of the cylinder as compared to a Newtonian fluid. These vortices oscillate in size and strength as A and alpha are varied. Hemoglobin enhances mass transport and is especially important for an air feed which is dominated by oxyhemoglobin dispersion near the cylinder. For a pure O(2) feed, oxygen transport in the plasma dominates near the cylinder. Maximum oxygen transport is achieved by operating near steady flow (small A) for both feed-gas mixtures. The time averaged Sherwood number, Sh, is found to be largely influenced by the steady Reynolds number, increasing as Re increases and decreasing with A. Little change is observed with varying alpha for the ranges investigated. The effect of pulsatility on Sh is greater at larger Re. Increasing Re aids transport, but yields a higher cylinder drag force and shear stresses on the cylinder surface which are potentially undesirable.

Overall Heat Transfer Coefficients for a Horizontal Cylinder in a Fluidized Bed.

DTIC Science & Technology

1984-04-01

The distribution system is composed of 2 in. PVC pipe and fittings arranged in a convenient air-tight geometry. Pressure regulators, pressure gauges...uniform fluidization. After i£ A_ 4 passing through the beads, the air is exhausted to the outside by means of galvanized duct work. Fluidized Bed...design is the matching with the copper cylinder of outer diameters, the fastening with recessed set screws , their length and the material selection. In

High frequency scattering by a smooth coated cylinder simulated with generalized impedance boundary conditions

NASA Technical Reports Server (NTRS)

Syed, Hasnain H.; Volakis, John L.

1991-01-01

Rigorous uniform geometrical theory of diffraction (UGTD) diffraction coefficients are presented for a coated convex cylinder simulated with generalized impedance boundary conditions. In particular, ray solutions are obtained which remain valid in the transition region and reduce uniformly to those in the deep lit and shadow regions. These involve new transition functions in place of the usual Fock-type integrals, characteristic to the impedance cylinder. A uniform asymptotic solution is also presented for observations in the close vicinity of the cylinder. As usual, the diffraction coefficients for the convex cylinder are obtained via a generalization of the corresponding ones for the circular cylinder.

49 CFR 178.46 - Specification 3AL seamless aluminum cylinders.

Code of Federal Regulations, 2010 CFR

2010-10-01

... material; or (ii) Obtaining a certified chemical analysis from the material or cylinder manufacturer for each melt, or cast of material; or (iii) Obtaining a certified check analysis on one cylinder out of...) Selecting the samples for check analyses performed by other than the material producer; (ii) Verifying that...

An unattended verification station for UF 6 cylinders: Field trial findings

DOE PAGES

Smith, L. E.; Miller, K. A.; McDonald, B. S.; ...

2017-08-26

In recent years, the International Atomic Energy Agency (IAEA) has pursued innovative techniques and an integrated suite of safeguards measures to address the verification challenges posed by the front end of the nuclear fuel cycle. Among the unattended instruments currently being explored by the IAEA is an Unattended Cylinder Verification Station (UCVS), which could provide automated, independent verification of the declared relative enrichment, 235U mass, total uranium mass, and identification for all declared uranium hexafluoride cylinders in a facility (e.g., uranium enrichment plants and fuel fabrication plants). Under the auspices of the United States and European Commission Support Programs tomore » the IAEA, a project was undertaken to assess the technical and practical viability of the UCVS concept. The first phase of the UCVS viability study was centered on a long-term field trial of a prototype UCVS system at a fuel fabrication facility. A key outcome of the study was a quantitative performance evaluation of two nondestructive assay (NDA) methods being considered for inclusion in a UCVS: Hybrid Enrichment Verification Array (HEVA), and Passive Neutron Enrichment Meter (PNEM). This paper provides a description of the UCVS prototype design and an overview of the long-term field trial. In conclusion, analysis results and interpretation are presented with a focus on the performance of PNEM and HEVA for the assay of over 200 “typical” Type 30B cylinders, and the viability of an “NDA Fingerprint” concept as a high-fidelity means to periodically verify that material diversion has not occurred.« less

An unattended verification station for UF 6 cylinders: Field trial findings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, L. E.; Miller, K. A.; McDonald, B. S.

In recent years, the International Atomic Energy Agency (IAEA) has pursued innovative techniques and an integrated suite of safeguards measures to address the verification challenges posed by the front end of the nuclear fuel cycle. Among the unattended instruments currently being explored by the IAEA is an Unattended Cylinder Verification Station (UCVS), which could provide automated, independent verification of the declared relative enrichment, 235U mass, total uranium mass, and identification for all declared uranium hexafluoride cylinders in a facility (e.g., uranium enrichment plants and fuel fabrication plants). Under the auspices of the United States and European Commission Support Programs tomore » the IAEA, a project was undertaken to assess the technical and practical viability of the UCVS concept. The first phase of the UCVS viability study was centered on a long-term field trial of a prototype UCVS system at a fuel fabrication facility. A key outcome of the study was a quantitative performance evaluation of two nondestructive assay (NDA) methods being considered for inclusion in a UCVS: Hybrid Enrichment Verification Array (HEVA), and Passive Neutron Enrichment Meter (PNEM). This paper provides a description of the UCVS prototype design and an overview of the long-term field trial. In conclusion, analysis results and interpretation are presented with a focus on the performance of PNEM and HEVA for the assay of over 200 “typical” Type 30B cylinders, and the viability of an “NDA Fingerprint” concept as a high-fidelity means to periodically verify that material diversion has not occurred.« less

An unattended verification station for UF6 cylinders: Field trial findings

NASA Astrophysics Data System (ADS)

Smith, L. E.; Miller, K. A.; McDonald, B. S.; Webster, J. B.; Zalavadia, M. A.; Garner, J. R.; Stewart, S. L.; Branney, S. J.; Todd, L. C.; Deshmukh, N. S.; Nordquist, H. A.; Kulisek, J. A.; Swinhoe, M. T.

2017-12-01

In recent years, the International Atomic Energy Agency (IAEA) has pursued innovative techniques and an integrated suite of safeguards measures to address the verification challenges posed by the front end of the nuclear fuel cycle. Among the unattended instruments currently being explored by the IAEA is an Unattended Cylinder Verification Station (UCVS), which could provide automated, independent verification of the declared relative enrichment, 235U mass, total uranium mass, and identification for all declared uranium hexafluoride cylinders in a facility (e.g., uranium enrichment plants and fuel fabrication plants). Under the auspices of the United States and European Commission Support Programs to the IAEA, a project was undertaken to assess the technical and practical viability of the UCVS concept. The first phase of the UCVS viability study was centered on a long-term field trial of a prototype UCVS system at a fuel fabrication facility. A key outcome of the study was a quantitative performance evaluation of two nondestructive assay (NDA) methods being considered for inclusion in a UCVS: Hybrid Enrichment Verification Array (HEVA), and Passive Neutron Enrichment Meter (PNEM). This paper provides a description of the UCVS prototype design and an overview of the long-term field trial. Analysis results and interpretation are presented with a focus on the performance of PNEM and HEVA for the assay of over 200 "typical" Type 30B cylinders, and the viability of an "NDA Fingerprint" concept as a high-fidelity means to periodically verify that material diversion has not occurred.

Longitudinal Weld Land Buckling in Compression-Loaded Orthogrid Cylinders

NASA Technical Reports Server (NTRS)

Thornburgh, Robert P.; Hilburger, Mark W.

2010-01-01

Large stiffened cylinders used in launch vehicles (LV), such as the Space Shuttle External Tank, are manufactured by welding multiple curved panel sections into complete cylinders. The effects of the axial weld lands between the panel sections on the buckling load were studied, along with the interaction between the acreage stiffener arrangement and the weld land geometry. This document contains the results of the studies.

Research on torsional vibration modelling and control of printing cylinder based on particle swarm optimization

NASA Astrophysics Data System (ADS)

Wang, Y. M.; Xu, W. C.; Wu, S. Q.; Chai, C. W.; Liu, X.; Wang, S. H.

2018-03-01

The torsional oscillation is the dominant vibration form for the impression cylinder of printing machine (printing cylinder for short), directly restricting the printing speed up and reducing the quality of the prints. In order to reduce torsional vibration, the active control method for the printing cylinder is obtained. Taking the excitation force and moment from the cylinder gap and gripper teeth open & closing cam mechanism as variable parameters, authors establish the dynamic mathematical model of torsional vibration for the printing cylinder. The torsional active control method is based on Particle Swarm Optimization(PSO) algorithm to optimize input parameters for the serve motor. Furthermore, the input torque of the printing cylinder is optimized, and then compared with the numerical simulation results. The conclusions are that torsional vibration active control based on PSO is an availability method to the torsional vibration of printing cylinder.

Flow around a slotted circular cylinder at various angles of attack

NASA Astrophysics Data System (ADS)

Gao, Dong-Lai; Chen, Wen-Li; Li, Hui; Hu, Hui

2017-10-01

We experimentally investigated the flow characteristics around a circular cylinder with a slot at different angles of attack. The experimental campaign was performed in a wind tunnel at the Reynolds number of Re = 2.67 × 104. The cylindrical test model was manufactured with a slot at the slot width S = 0.075 D ( D is the diameter of the cylinder). The angle of attack α was varied from 0° to 90°. In addition to measuring the pressure distributions around the cylinder surface, a digital particle image velocimetry (PIV) system was employed to quantify the wake flow characteristics behind the baseline cylinder (i.e., baseline case of the cylinder without slot) and slotted cylinder at various angles of attack. Measurement results suggested that at low angles of attack, the passive jet flow generated by the slot would work as an effective control scheme to modify the wake flow characteristics and contribute to reducing the drag and suppressing the fluctuating lift. The flip-flop phenomenon was also identified and discussed with the slot at 0° angle of attack. As the angle of attack α became 45°, the effects of the slot were found to be minimal. When the angle of attack α of the slot approached 90°, the self-organized boundary layer suction and blowing were realized. As a result, the flow separations on both sides of the test model were found to be notably delayed, the wake width behind the slotted cylinder was decreased and the vortex formation length was greatly shrunk, in comparison with the baseline case. Instantaneous pressure measurement results revealed that the pressure difference between the two slot ends and the periodically fluctuating pressure distributions would cause the alternative boundary layer suction and blowing at α = 90°.

78 FR 58604 - Safety Advisory: Unauthorized Filling of Compressed Gas Cylinders

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-24

... questions the condition of all of the cylinders owned and filled by Komer Carbonic Corp. in the past 5 years... through a visual inspection and a pressure test at least once every 5 years. Cylinders that are not...

Inductance position sensor for pneumatic cylinder

NASA Astrophysics Data System (ADS)

Ripka, Pavel; Chirtsov, Andrey; Mirzaei, Mehran; Vyhnanek, Jan

2018-04-01

The position of the piston in pneumatic cylinder with aluminum wall can be measured by external inductance sensor without modifications of the aluminum piston and massive iron piston rod. For frequencies below 20 Hz the inductance is increasing with inserting rod due to the rod permeability. This mode has disadvantage of slow response to piston movement and also high temperature sensitivity. At the frequency of 45 Hz the inductance is position independent, as the permeability effect is compensated by the eddy current effect. At higher frequencies eddy current effects in the rod prevail, the inductance is decreasing with inserting rod. In this mode the sensitivity is smaller but the sensor response is fast and temperature stability is better. We show that FEM simulation of this sensor using measured material properties gives accurate results, which is important for the sensor optimization such as designing the winding geometry for the best linearity.

Buckling Response of a Large-Scale, Seamless, Orthogrid-Stiffened Metallic Cylinder

NASA Technical Reports Server (NTRS)

Rudd, Michelle Tillotson; Hilburger, Mark W.; Lovejoy, Andrew E.; Lindell, Michael C.; Gardner, Nathaniel W.; Schultz, Marc R.

2018-01-01

Results from the buckling test of a compression-loaded 8-ft-diameter seamless (i.e., without manufacturing joints), orthogrid-stiffened metallic cylinder are presented. This test was used to assess the buckling response and imperfection sensitivity characteristics of a seamless cylinder. In addition, the test article and test served as a technology demonstration to show the application of the flow forming manufacturing process to build more efficient buckling-critical structures by eliminating the welded joints that are traditionally used in the manufacturing of large metallic barrels. Pretest predictions of the cylinder buckling response were obtained using a finite-element model that included measured geometric imperfections. The buckling load predicted using this model was 697,000 lb, and the test article buckled at 743,000 lb (6% higher). After the test, the model was revised to account for measured variations in skin and stiffener geometry, nonuniform loading, and material properties. The revised model predicted a buckling load of 754,000 lb, which is within 1.5% of the tested buckling load. In addition, it was determined that the load carrying capability of the seamless cylinder is approximately 28% greater than a corresponding cylinder with welded joints.

Multiple buoyancy driven flows in a vertical cylinder heated from below

NASA Technical Reports Server (NTRS)

Yamaguchi, Y.; Chang, C. J.; Brown, R. A.

1983-01-01

The structure of axisymmetric buoyancy-driven convection in a vertical cylinder heated from below is probed by finite element solution of the Boussinesq equations coupled with computed-implemented perturbation techniques for detecting and tracking multiple flows and for determining flow stability. Results are reported for fluids with Prandtl number of one and for cylinders with aspect ratio (Lambda) (defined as the height to radius of the cylinder) between 0.5 and 2.25. Extensive calculations of the neutral stability curve for the static solution and of the nonlinear motions along the bifurcating flow families show a continuous evolution of the primary cellular motion from a single toroidal cell to two and three cells nested radially in the cylinder, instead of the sharp transitions found for a cylinder with shear-free sidewalls. The smooth transitions in flow structure with Rayleigh number and lambda are explained by nonlinear connectivity between the first two bifurcating flow families formed either by a secondary bifurcation point for Lambda or = Lambda * approximately 0.80 or by a limit point for Lambda Lambda *. The transition between these two modes may be described by the theory of multiple limit point bifurcation.

Review of corrosion in 10- and 14-ton mild steel depleted UF{sub 6} storage cylinders

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lykins, M.L.

1995-08-01

A literature review was conducted to determine the type, extent and severity of corrosion found in the 10- and 14-ton mild steel depleted UF{sub 6} storage cylinders. Also discussed in this review is corrosion found in the valves and plugs used in the cylinders. Corrosion of the cylinders is a gradual process which occurs slowly over time. Understanding corrosion of the cylinders is an important concern for long term storage of the UF{sub 6} in the cylinder yards, as well as the final disposition of the depleted UF{sub 6} tails inventory in the future. The following conclusions are made frommore » the literature review: (1) The general external corrosion rate of the cylinders is about 1 to 2 mils per year (1 mil = 0.001{double_prime}). The highest general external corrosion rate was over 5 mpy on the 48G type cylinders. (2) General internal corrosion from the depleted UF{sub 6} is negligible under normal storage conditions. Crevice corrosion can occur at the cylinder/saddle interface from the retention of water in this area. Crevice corrosion can occur at the cylinder/skirt interface on the older skirted cylinders due to the lack of water drainage in this area. Crevice corrosion can occur on cylinders that have been in ground contact. Crevice corrosion and galvanic corrosion can occur where the stainless steel I.D. nameplates are attached to the cylinder. The packing nuts on the bronze one-inch valves used in the cylinders are susceptible to stress corrosion cracking (SCC). Mechanical damage from routine handling can lead to a breach in a cylinder with subsequent accelerated corrosion of the mild steel due to attack from HF and other UF{sub 6} hydrolysis by-products.« less

Numerical Investigation of Flow Around Rectangular Cylinders with and Without Jets

NASA Technical Reports Server (NTRS)

Tiwari, S. N .; Pidugu, S. B.

1999-01-01

The problem of flow past bluff bodies was studied extensively in the past. The problem of drag reduction is very important in many high speed flow applications. Considerable work has been done in this subject area in case of circular cylinders. The present study attempts to investigate the feasibility of drag reduction on a rectangular cylinder by flow injection by flow injection from the rear stagnation region. The physical problem is modeled as two-dimensional body and numerical analysis is carried out with and without trailing jets. A commercial code is used for this purpose. Unsteady computation is performed in case of rectangular cylinders with no trailing jets where as steady state computation is performed when jet is introduced. It is found that drag can be reduced by introducing jets with small intensity in rear stagnation region of the rectangular cylinders.

49 CFR 178.36 - Specification 3A and 3AX seamless steel cylinders.

Code of Federal Regulations, 2011 CFR

2011-10-01

... conform to the following: (1) A DOT-3A cylinder is a seamless steel cylinder with a water capacity... steel cylinder with a water capacity not less than 1,000 pounds and a service pressure of at least 500... per unit of length of the straight cylindrical portion filled with water and compressed to the...

49 CFR 178.36 - Specification 3A and 3AX seamless steel cylinders.

Code of Federal Regulations, 2010 CFR

2010-10-01

... conform to the following: (1) A DOT-3A cylinder is a seamless steel cylinder with a water capacity... steel cylinder with a water capacity not less than 1,000 pounds and a service pressure of at least 500... per unit of length of the straight cylindrical portion filled with water and compressed to the...

49 CFR 178.37 - Specification 3AA and 3AAX seamless steel cylinders.

Code of Federal Regulations, 2011 CFR

2011-10-01

... conform to the following: (1) A DOT-3AA cylinder is a seamless steel cylinder with a water capacity... a seamless steel cylinder with a water capacity of not less than 1,000 pounds and a service pressure... the weight per unit of length of the straight cylindrical portion filled with water and compressed to...

Nonlinear state-space modelling of the kinematics of an oscillating circular cylinder in a fluid flow

NASA Astrophysics Data System (ADS)

Decuyper, J.; De Troyer, T.; Runacres, M. C.; Tiels, K.; Schoukens, J.

2018-01-01

The flow-induced vibration of bluff bodies is an important problem of many marine, civil, or mechanical engineers. In the design phase of such structures, it is vital to obtain good predictions of the fluid forces acting on the structure. Current methods rely on computational fluid dynamic simulations (CFD), with a too high computational cost to be effectively used in the design phase or for control applications. Alternative methods use heuristic mathematical models of the fluid forces, but these lack the accuracy (they often assume the system to be linear) or flexibility to be useful over a wide operating range. In this work we show that it is possible to build an accurate, flexible and low-computational-cost mathematical model using nonlinear system identification techniques. This model is data driven: it is trained over a user-defined region of interest using data obtained from experiments or simulations, or both. Here we use a Van der Pol oscillator as well as CFD simulations of an oscillating circular cylinder to generate the training data. Then a discrete-time polynomial nonlinear state-space model is fit to the data. This model relates the oscillation of the cylinder to the force that the fluid exerts on the cylinder. The model is finally validated over a wide range of oscillation frequencies and amplitudes, both inside and outside the so-called lock-in region. We show that forces simulated by the model are in good agreement with the data obtained from CFD.

Numerical simulation and experiment on split tungsten carbide cylinder of high pressure apparatus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Yunfei; Li, Mingzhe, E-mail: limz@jlu.edu.cn; Wang, Bolong

2015-12-15

A new high pressure device with a split cylinder was investigated on the basis of the belt-type apparatus. The belt-type die is subjected to excessive tangential tensile stress and the tungsten carbide cylinder is easily damaged in the running process. Taking into account the operating conditions and material properties of the tungsten carbide cylinder, it is divided into 6 blocks to eliminate the tangential tensile stress. We studied two forms of the split type: radial split and tangential split. Simulation results indicate that the split cylinder has more uniform stress distribution and smaller equivalent stress compared with the belt-type cylinder.more » The inner wall of the tangential split cylinder is in the situation that compressive stress is distributed in the axial, radial, and tangential directions. It is similar to the condition of hydrostatic pressure, and it is the best condition for tungsten carbide materials. The experimental results also verify that the tangential split die can bear the highest chamber pressure. Therefore, the tangential split structure can increase the pressure bearing capacity significantly.« less

Thermal convection of liquid sodium in inclined cylinders

NASA Astrophysics Data System (ADS)

Khalilov, Ruslan; Kolesnichenko, Ilya; Pavlinov, Alexander; Mamykin, Andrey; Shestakov, Alexander; Frick, Peter

2018-04-01

The effect of inclination on the low Prandtl number turbulent convection in a cylinder of unit aspect ratio was studied experimentally. The working fluid was sodium (Prandtl number Pr =0.0094 ), the measurements were performed for a fixed Rayleigh number Ra =(1.47 ±0.03 ) ×107 , and the inclination angle varied from β =0∘ (the Rayleigh-Bénard convection, the temperature gradient is vertical) up to β =90∘ (the applied temperature gradient is horizontal) with a step Δ β =10∘ . The effective axial heat flux characterized by the Nusselt number is minimal at β =0∘ and demonstrates a smooth growth with the increase of the cylinder inclination, reaching a maximum at angle β ≈70∘ and decreasing with a further increase of β . The maximal value of the normalized Nusselt number Nu (β )/Nu (0 ) was 1.21. In general, the dependence of Nu (β ) in a cylinder with unit aspect ratio is similar to what was observed in sodium convection in inclined long cylinders but is much weaker. The structure of the flow undergoes a significant transformation with inclination. Under moderate inclination (β ≲30∘ ), the fluctuations are strong and are provided by regular oscillations of large-scale circulation (LSC) and by turbulence. Under large inclination (β >60∘ ), the LSC is regular and the turbulence is weak, while in transient regimes (30∘<β <60∘ ), the LSC fluctuations are weak and the turbulence decreases with inclination. The maximum Nusselt number corresponds to the border of transient and large inclinations. We find the first evidence of strong LSC fluctuations in low Prandtl number convective flow under moderate inclination. The rms azimuthal fluctuations of LSC, about 27∘ at β =0∘ , decrease almost linearly up to β =30∘ , where they are about 9∘. The angular fluctuations in the vicinity of the end faces are much stronger (about 37∘ at β =0∘ ) and weakly decrease up to β =20∘ . The strong anticorrelation of the fluctuations in two

Efficacy and safety of cross-cylinder photorefractive keratectomy versus single method in medium-high astigmatism: a randomized clinical trial.

PubMed

Sedghipour, Mohammad R; Lotfi, Afshin; Sadeghilar, Ayaz; Banan, Saeeid

2012-09-07

BACKGROUND: To compare efficacy and safety of photorefractive keratectomy (PRK) by cross-cylinder with single methods in medium-high astigmatism. DESIGN: Randomized clinical trial study PARTICIPANTS: Fifty patients with medium-high compound myopic astigmatism were enrolled between September 2007 and September 2008. METHODS: PRK was performed on 100 eyes of 50 patients with compound myopic astigmatism. Each patient underwent PRK by cross-cylinder approach in one eye and single method on the contralateral eye. Vector analysis was used to assess astigmatic results. MAIN OUTCOME MEASURES: Improvement of visual acuity (snelen chart), refraction, aberrometry. RESULTS: Uncorrected visual acuity (UCCA) equal to 20/40 or better after six months, was achieved in 98% of eyes in the cross-cylinder method versus 96% in single method.. Mean preoperative spherical equivalent(SE) was -5.2 ±2.1 D in the cross-cylinder method versus -5.1 ±0.5 D in the single method. At six months, the mean SE was - 0.5±0.4 D and -0.6±0.3 D, respectively. Mean IOS was 0.4±0.3 in the cross-cylinder group and 0.4±0.4 in the single group. Mean postoperative absolute change in total root-mean-square higher order aberrations in the cross-cylinder group and single group were 0.16 pm and 0.17 pm, respectively. Any of the mentioned differences didn't appear to be statistically significant. CONCLUSIONS: Both PRK methods appeared to be safe and effective in correcting medium-high astigmatism. © 2012 The Author. Clinical and Experimental Ophthalmology © 2012 Royal Australian and New Zealand College of Ophthalmologists.

The Federal Cylinder Project: A Guide to Field Cylinder Collections in Federal Agencies. Volume 3, Great Basin/Plateau Indian Catalog, Northwest Coast/Arctic Indian Catalog.

ERIC Educational Resources Information Center

Gray, Judith A., Ed.

Two catalogs inventory wax cylinder collections, field recorded among Native American groups, 1890-1942. The catalog for Great Basin and Plateau Indian tribes contains entries for 174 cylinders in 7 collections from the Flathead, Nez Perce, Thompson/Okanagon, Northern Ute, and Yakima tribes. The catalog for Northwest Coast and Arctic Indian tribes…

49 CFR 178.68 - Specification 4E welded aluminum cylinders.

Code of Federal Regulations, 2011 CFR

2011-10-01

...) Where: S = wall stress in psi; P = minimum test pressure prescribed for water jacket test; D = outside... and service pressure. A DOT 4E cylinder is a welded aluminum cylinder with a water capacity (nominal... stress at twice service pressure may not exceed the lesser value of either of the following: (i) 20,000...

49 CFR 178.45 - Specification 3T seamless steel cylinder.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., and service pressure. A DOT 3T cylinder is a seamless steel cylinder with a minimum water capacity of...) Wall thickness. The minimum wall thickness must be such that the wall stress at the minimum specified... the physical tests required in paragraphs (j) and (k) of this section. A wall stress of more than 90...

Stress distribution and pressure-bearing capacity of a high-pressure split-cylinder die with prism cavity

NASA Astrophysics Data System (ADS)

Zhao, Liang; Li, Mingzhe; Wang, Liyan; Qu, Erhu; Yi, Zhuo

2018-03-01

A novel high-pressure belt-type die with a split-type cylinder is investigated with respect to extending its lifetime and improving its pressure bearing capacity. Specifically, a tungsten carbide cylinder is split into several parts along the radial direction with a prism-type cavity. In this paper, the cylinders with different split numbers are chosen to study the stress distribution and compare them with the traditional belt-type die. The simulation results indicate that the split cylinder has much smaller stress than those in the belt-type cylinder, and the statistical analysis reveals that the split-pressure cylinder is able to bear higher pressure. Experimental tests also show that the high-pressure die with a split cylinder and prism cavity has a stronger pressure-bearing capacity than a belt-type die. The split cylinder has advantages of easy manufacturing, high pressure bearing capacity, and replaceable performance.

Effect of intake swirl on the performance of single cylinder direct injection diesel engine

NASA Astrophysics Data System (ADS)

Sharma, Vinod Kumar; Mohan, Man; Mouli, Chandra

2017-11-01

In the present work, the effect of inlet manifold geometry and swirl intensity on the direct injection (DI) diesel engine performance was investigated experimentally. Modifications in inlet manifold geometry have been suggested to achieve optimized swirl for the better mixing of fuel with air. The intake swirl intensities of modified cylinder head were measured in swirl test rig at different valve lifts. Later, the overall performance of 435 CC DI diesel engine was measured using modified cylinder head. In addition, the performance of engine was compared for both modified and old cylinder head. For same operating conditions, the brake power and brake specific fuel consumption was improved by 6% and 7% respectively with modified cylinder head compared to old cylinder head. The maximum brake power of 9 HP was achieved for modified cylinder head. The results revealed that the intake swirl has great influence on engine performance.

Bending Tests of Circular Cylinders of Corrugated Aluminum-alloy Sheet

NASA Technical Reports Server (NTRS)

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

1937-01-01

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

Antisymmetric vortex interactions in the wake behind a step cylinder

NASA Astrophysics Data System (ADS)

Tian, Cai; Jiang, Fengjian; Pettersen, Bjørnar; Andersson, Helge I.

2017-10-01

Flow around a step cylinder at the Reynolds number 150 was simulated by directly solving the full Navier-Stokes equations. The configuration was adopted from the work of Morton and Yarusevych ["Vortex shedding in the wake of a step cylinder," Phys. Fluids 22, 083602 (2010)], in which the wake dynamics were systematically described. A more detailed investigation of the vortex dislocation process has now been performed. Two kinds of new loop vortex structures were identified. Additionally, antisymmetric vortex interactions in two adjacent vortex dislocation processes were observed and explained. The results in this letter serve as a supplement for a more thorough understanding of the vortex dynamics in the step cylinder wake.

Hidden Criticality of Counterion Condensation Near a Charged Cylinder.

PubMed

Cha, Minryeong; Yi, Juyeon; Kim, Yong Woon

2017-09-05

Counterion condensation onto a charged cylinder, known as the Manning transition, has received a great deal of attention since it is essential to understand the properties of polyelectrolytes in ionic solutions. However, the current understanding is still far from complete and poses a puzzling question: While the strong-coupling theory valid at large ionic correlations suggests a discontinuous nature of the counterion condensation, the mean-field theory always predicts a continuous transition at the same critical point. This naturally leads to a question how one can reconcile the mean-field theory with the strong-coupling prediction. Here, we study the counterion condensation transition on a charged cylinder via Monte Carlo simulations. Varying the cylinder radius systematically in relation to the system size, we find that in addition to the Manning transition, there exists a novel transition where all counterions are bound to the cylinder and the heat capacity shows a drop at a finite Manning parameter. A finite-size scaling analysis is carried out to confirm the criticality of the complete condensation transition, yielding the same critical exponents with the Manning transition. We show that the existence of the complete condensation is essential to explain how the condensation nature alters from continuous to discontinuous transition.

Correlation of Cooling Data from an Air-Cooled Cylinder and Several Multicylinder Engines

NASA Technical Reports Server (NTRS)

Pinkel, Benjamin; Ellerbrock, Herman H , Jr

1940-01-01

The theory of engine-cylinder cooling developed in a previous report was further substantiated by data obtained on a cylinder from a Wright r-1820-g engine. Equations are presented for the average head and barrel temperatures of this cylinder as functions of the engine and the cooling conditions. These equations are utilized to calculate the variation in cylinder temperature with altitude for level flight and climb. A method is presented for correlating average head and barrel temperatures and temperatures at individual points on the head and the barrel obtained on the test stand and in flight. The method is applied to the correlation and the comparison of data obtained on a number of service engines. Data are presented showing the variation of cylinder temperature with time when the power and the cooling pressure drop are suddenly changed.

Multi-surface topography targeted plateau honing for the processing of cylinder liner surfaces of automotive engines

NASA Astrophysics Data System (ADS)

Lawrence, K. Deepak; Ramamoorthy, B.

2016-03-01

Cylinder bores of automotive engines are 'engineered' surfaces that are processed using multi-stage honing process to generate multiple layers of micro geometry for meeting the different functional requirements of the piston assembly system. The final processed surfaces should comply with several surface topographic specifications that are relevant for the good tribological performance of the engine. Selection of the process parameters in three stages of honing to obtain multiple surface topographic characteristics simultaneously within the specification tolerance is an important module of the process planning and is often posed as a challenging task for the process engineers. This paper presents a strategy by combining the robust process design and gray-relational analysis to evolve the operating levels of honing process parameters in rough, finish and plateau honing stages targeting to meet multiple surface topographic specifications on the final running surface of the cylinder bores. Honing experiments were conducted in three stages namely rough, finish and plateau honing on cast iron cylinder liners by varying four honing process parameters such as rotational speed, oscillatory speed, pressure and honing time. Abbott-Firestone curve based functional parameters (Rk, Rpk, Rvk, Mr1 and Mr2) coupled with mean roughness depth (Rz, DIN/ISO) and honing angle were measured and identified as the surface quality performance targets to be achieved. The experimental results have shown that the proposed approach is effective to generate cylinder liner surface that would simultaneously meet the explicit surface topographic specifications currently practiced by the industry.

49 CFR 178.39 - Specification 3BN seamless nickel cylinders.

Code of Federal Regulations, 2010 CFR

2010-10-01

...) Type, size and service pressure. A DOT 3BN cylinder is a seamless nickel cylinder with a water capacity (nominal) not over 125 pounds water capacity (nominal) and a service pressure at least 150 to not over 500...) Wall thickness. The wall stress may not exceed 15,000 psi. A minimum wall thickness of 0.100 inch is...

49 CFR 178.39 - Specification 3BN seamless nickel cylinders.

Code of Federal Regulations, 2011 CFR

2011-10-01

...) Type, size and service pressure. A DOT 3BN cylinder is a seamless nickel cylinder with a water capacity (nominal) not over 125 pounds water capacity (nominal) and a service pressure at least 150 to not over 500...) Wall thickness. The wall stress may not exceed 15,000 psi. A minimum wall thickness of 0.100 inch is...

Optimal illusion and invisibility of multilayered anisotropic cylinders and spheres.

PubMed

Zhang, Lin; Shi, Yan; Liang, Chang-Hong

2016-10-03

In this paper, full-wave electromagnetic scattering theory is employed to investigate illusion and invisibility of inhomogeneous anisotropic cylinders and spheres. With the use of a shell designed according to Mie series theory for multiple piecewise anisotropic layers, radar cross section (RCS) of the coated inhomogeneous anisotropic object can be dramatically reduced or disguised as another object in the long-wavelength limit. With the suitable adjustment of the anisotropy parameters of the shell, optimal illusion and invisibility characteristics of the coated inhomogeneous anisotropic object can be achieved. Details of theoretical analysis and numerical examples are presented to validate the proposed methodology.

Natural phenomena evaluations of the K-25 site UF{sub 6} cylinder storage yards

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fricke, K.E.

1996-09-15

The K-25 Site UF{sub 6} cylinder storage yards are used for the temporary storage of UF{sub 6} normal assay cylinders and long-term storage of other UF{sub 6} cylinders. The K-25 Site UF{sub 6} cylinder storage yards consist of six on-site areas: K-1066-B, K-1066-E, K-1066-F, K-1066-J, K-1066-K and K-1066-L. There are no permanent structures erected on the cylinder yards, except for five portable buildings. The operating contractor for the K-25 Site is preparing a Safety Analysis Report (SAR) to examine the safety related aspects of the K-25 Site UF{sub 6} cylinder storage yards. The SAR preparation encompasses many tasks terminating inmore » consequence analysis for the release of gaseous and liquid UF{sub 6}, one of which is the evaluation of natural phenomena threats, such as earthquakes, floods, and winds. In support of the SAR, the six active cylinder storage yards were evaluated for vulnerabilities to natural phenomena, earthquakes, high winds and tornados, tornado-generated missiles, floods (local and regional), and lightning. This report summarizes those studies. 30 refs.« less

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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 arraymore » 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.« less

Design and analysis of an electromagnetic turnout for the superconducting Maglev system

NASA Astrophysics Data System (ADS)

Li, Y. J.; Dai, Q.; Zhang, Y.; Wang, H.; Chen, Z.; Sun, R. X.; Zheng, J.; Deng, C. Y.; Deng, Z. G.

2016-09-01

Turnout is a crucial track junction device of the ground rail transportation system. For high temperature superconducting (HTS) Maglev system, the permanent magnet guideway (PMG) makes the strong magnetic force existing between rail segments, which may cause moving difficulties and increase the operation cost when switching a PMG. In this paper, a non-mechanical 'Y' shaped Halbach-type electromagnetic turnout was proposed. By replacing the PMs with electromagnets, the turnout can guide the maglev vehicle running into another PMG by simply controlling the current direction of electromagnets. The material and structure parameters of the electromagnets were optimized by simulation. The results show that the optimized electromagnet can keep the magnetic field above it as strong as the PMs', meanwhile feasible for design and manufacture. This work provides valuable references for the future design in non-mechanical PMG turnout.

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.

Numerical investigation of cylinder wake flow with a rear stagnation jet

NASA Astrophysics Data System (ADS)

Mo, J. D.; Duke, M. R., Jr.

1994-05-01

Upon visualization of the flow past a cylinder with a rear stagnation jet (RSJ), the flow appears fully attached as conventional inviscid flow does. Therefore, at first glance, it would be suspected that the form drag on the cylinder has been reduced to zero as predicted by inviscid flow theory. However, a detailed numerical simulation reveals that the form drag coefficient increases as the jet velocity increases. The mechanics of the increasing form drag are addressed. The following conclusions were drawn: (1) flow behind a cylinder can be effectively influenced by a RSJ; (2) the unsymmetric wake flow becomes symmetric when the RSI is in operation with a velocity ratio as low as 1; the size of the symmetric recirculation region becomes smaller as the jet speed increases; (3) a RSJ forces a symmetrical wake flow pattern, thus eliminating the lateral force; (4) the pressure on the cylinder surface decreases over the entire surface, but significantly more on the downstream side of the cylinder, as the jet velocity increases, causing an increase in form drag as jet velocity ratio increases; and (5) the RSJ to significantly increase form drag on a bluff body has direct applications in aerodynamic controls of reentry or fligths at high angles of attack.

Inductrack magnet configuration

DOEpatents

Post, Richard Freeman

2003-12-16

A magnet configuration comprising a pair of Halbach arrays magnetically and structurally connected together are positioned with respect to each other so that a first component of their fields substantially cancels at a first plane between them, and a second component of their fields substantially adds at this first plane. A track of windings is located between the pair of Halbach arrays and a propulsion mechanism is provided for moving the pair of Halbach arrays along the track. When the pair of Halbach arrays move along the track and the track is not located at the first plane, a current is induced in the windings and a restoring force is exerted on the pair of Halbach arrays.

Inductrack magnet configuration

DOEpatents

Post, Richard Freeman

2003-10-14

A magnet configuration comprising a pair of Halbach arrays magnetically and structurally connected together are positioned with respect to each other so that a first component of their fields substantially cancels at a first plane between them, and a second component of their fields substantially adds at this first plane. A track of windings is located between the pair of Halbach arrays and a propulsion mechanism is provided for moving the pair of Halbach arrays along the track. When the pair of Halbach arrays move along the track and the track is not located at the first plane, a current is induced in the windings and a restoring force is exerted on the pair of Halbach arrays.

Effect of Fin Passage Length on Optimization of Cylinder Head Cooling Fins

NASA Technical Reports Server (NTRS)

Siegel, R.; Graham, R. W.

1977-01-01

The heat transfer performance of baffled cooling fins on cylinder heads of small, air-cooled, general-aviation aircraft engines was analyzed to determine the potential for improving cooling fin design. Flow baffles were assumed to be installed tightly against the fin end edges, an ideal baffle configuration for guiding all flow between the fins. A rectangular flow passage is thereby formed between each set of two adjacent fins, the fin base surface, and the baffle. These passages extend around each side of the cylinder head, and the cooling air absorbs heat as it flows within them. For each flow passage length, the analysis was concerned with optimizing fin spacing and thickness to achieve the best heat transfer for each fin width. Previous literature has been concerned mainly with maximizing the local fin conductance and has not considered the heating of the gas in the flow direction, which leads to higher wall temperatures at the fin passage exits. If the fins are close together, there is a large surface area, but the airflow is restricted.

Flow-induced oscillations of a floating moored cylinder

NASA Astrophysics Data System (ADS)

Carlson, Daniel; Modarres-Sadeghi, Yahya

2016-11-01

An experimental study of flow-induced oscillations of a floating model spar buoy was conducted. The model spar consisted of a floating uniform cylinder moored in a water tunnel test section, and free to oscillate about its mooring attachment point near the center of mass. For the bare cylinder, counter-clockwise (CCW) figure-eight trajectories approaching A* =1 in amplitude were observed at the lower part of the spar for a reduced velocity range of U* =4-11, while its upper part experienced clockwise (CW) orbits. It was hypothesized that the portion of the spar undergoing CCW figure eights is the portion within which the flow excites the structure. By adding helical strakes to the portion of the cylinder with CCW figure eights, the response amplitude was significantly reduced, while adding strakes to portions with clockwise orbital motion had a minimal influence on the amplitude of response. This work is partially supported by the NSF-sponsored IGERT: Offshore Wind Energy Engineering, Environmental Science, and Policy (Grant Number 1068864).

Ion acceleration in shell cylinders irradiated by a short intense laser pulse

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andreev, A.; ELI-ALPS, Szeged; Platonov, K.

The interaction of a short high intensity laser pulse with homo and heterogeneous shell cylinders has been analyzed using particle-in-cell simulations and analytical modeling. We show that the shell cylinder is proficient of accelerating and focusing ions in a narrow region. In the case of shell cylinder, the ion energy exceeds the ion energy for a flat target of the same thickness. The constructed model enables the evaluation of the ion energy and the number of ions in the focusing region.

Thermally driven film climbing a vertical cylinder

NASA Astrophysics Data System (ADS)

Smolka, Linda

2017-11-01

The dynamics of a Marangoni driven film climbing the outside of a vertical cylinder is examined in numerical simulations of a thin film model. The model has three parameters: the scaled cylinder radius R̂, upstream film height h∞ and downstream precursor film thickness b , and reduces to the model for Marangoni driven film climbing a vertical plate when R̂ -> ∞ . The advancing front displays dynamics similar to that along a vertical plate where, depending on h∞ , the film forms a Lax shock, an undercompressive double shock or a rarefaction-undercompressive shock. A linear stability analysis of the Lax shock reveals the number of fingers that form along the contact line increases linearly with cylinder circumference while no fingers form below R̂ 1.15 with b = 0.1 . The substrate curvature controls the Lax shock height, bounds on h∞ that define the three solutions and the maximum growth rate of perturbations when R̂ = O (1) , whereas the shape of solutions and the stability of the Lax shock converge to the behavior on a vertical plate when R̂ >= O (10) . The azimuthal curvatures of the base state and perturbation, arising from the annular geometry of the film, promote instability of the advancing contact line.

Experimental investigation on in-plane/out-of-plane vortex-induced vibrations of curved cylinder in parallel and perpendicular flows

NASA Astrophysics Data System (ADS)

Srinil, Narakorn; Ma, Bowen; Zhang, Licong

2018-05-01

This study is motivated by an industrial need to better understand the vortex-induced vibration (VIV) of a curved structure subject to current flows with varying directions whose data for model calibration and validation are lacking. In this paper, new experimental investigations on the two-degree-of-freedom in-plane/out-of-plane VIV of a rigid curved circular cylinder immersed in steady and uniform free-stream flows are presented. The principal objective is to examine how the approaching flow direction versus the cylinder curvature plane affects cross-flow and in-line VIV and the associated hydrodynamic properties. This is achieved by testing the curved cylinder in 3 different flow orientations comprising the parallel flows aligned with the curvature vertical plane in convex and concave configurations, and the flows perpendicular to the curvature plane. The case of varying flow velocities in a subcritical flow range with a maximum Reynolds number of about 50,000 is considered for the curved cylinder with a low mass ratio and damping ratio. Experimental results are presented and discussed in terms of the cylinder response amplitudes, inclination angles, mean displacements, motion trajectories, oscillation frequencies, hydrodynamic forces, relative phases, fluid excitation and added inertia coefficients. Comparisons with other experimental results of curved and straight cylinder VIV are also presented. The experiments highlight the important effects of cylinder curvature versus flow orientation on the combined cross-flow/in-line VIV. The maximum (minimum) responses occur in the perpendicular (convex) flow case whereas the extended lower-branch responses occur in the concave flow case. For perpendicular flows, some meaningful features are observed, including the appearances of cross-flow mean displacements and asymmetric eight-shaped motion trajectories due to multiple 2:1:1 resonances where two out-of-plane and one in-plane dominant frequencies are simultaneously

Adaptive robust motion trajectory tracking control of pneumatic cylinders with LuGre model-based friction compensation

NASA Astrophysics Data System (ADS)

Meng, Deyuan; Tao, Guoliang; Liu, Hao; Zhu, Xiaocong

2014-07-01

Friction compensation is particularly important for motion trajectory tracking control of pneumatic cylinders at low speed movement. However, most of the existing model-based friction compensation schemes use simple classical models, which are not enough to address applications with high-accuracy position requirements. Furthermore, the friction force in the cylinder is time-varying, and there exist rather severe unmodelled dynamics and unknown disturbances in the pneumatic system. To deal with these problems effectively, an adaptive robust controller with LuGre model-based dynamic friction compensation is constructed. The proposed controller employs on-line recursive least squares estimation (RLSE) to reduce the extent of parametric uncertainties, and utilizes the sliding mode control method to attenuate the effects of parameter estimation errors, unmodelled dynamics and disturbances. In addition, in order to realize LuGre model-based friction compensation, the modified dual-observer structure for estimating immeasurable friction internal state is developed. Therefore, a prescribed motion tracking transient performance and final tracking accuracy can be guaranteed. Since the system model uncertainties are unmatched, the recursive backstepping design technology is applied. In order to solve the conflicts between the sliding mode control design and the adaptive control design, the projection mapping is used to condition the RLSE algorithm so that the parameter estimates are kept within a known bounded convex set. Finally, the proposed controller is tested for tracking sinusoidal trajectories and smooth square trajectory under different loads and sudden disturbance. The testing results demonstrate that the achievable performance of the proposed controller is excellent and is much better than most other studies in literature. Especially when a 0.5 Hz sinusoidal trajectory is tracked, the maximum tracking error is 0.96 mm and the average tracking error is 0.45 mm. This

A critical evaluation of various methods for the analysis of flow-solid interaction in a nest of thin cylinders subjected to cross flows

NASA Technical Reports Server (NTRS)

Kim, Sang-Wook

1987-01-01

Various experimental, analytical, and numerical analysis methods for flow-solid interaction of a nest of cylinders subjected to cross flows are reviewed. A nest of cylinders subjected to cross flows can be found in numerous engineering applications including the Space Shuttle Maine Engine-Main Injector Assembly (SSME-MIA) and nuclear reactor heat exchangers. Despite its extreme importance in engineering applications, understanding of the flow-solid interaction process is quite limited and design of the tube banks are mostly dependent on experiments and/or experimental correlation equations. For future development of major numerical analysis methods for the flow-solid interaction of a nest of cylinders subjected to cross flow, various turbulence models, nonlinear structural dynamics, and existing laminar flow-solid interaction analysis methods are included.

Cylinders out of a top hat: counts-in-cells for projected densities

NASA Astrophysics Data System (ADS)

Uhlemann, Cora; Pichon, Christophe; Codis, Sandrine; L'Huillier, Benjamin; Kim, Juhan; Bernardeau, Francis; Park, Changbom; Prunet, Simon

2018-06-01

Large deviation statistics is implemented to predict the statistics of cosmic densities in cylinders applicable to photometric surveys. It yields few per cent accurate analytical predictions for the one-point probability distribution function (PDF) of densities in concentric or compensated cylinders; and also captures the density dependence of their angular clustering (cylinder bias). All predictions are found to be in excellent agreement with the cosmological simulation Horizon Run 4 in the quasi-linear regime where standard perturbation theory normally breaks down. These results are combined with a simple local bias model that relates dark matter and tracer densities in cylinders and validated on simulated halo catalogues. This formalism can be used to probe cosmology with existing and upcoming photometric surveys like DES, Euclid or WFIRST containing billions of galaxies.

The Present Status of Using Natural Gas Cylinders and Acoustic Emission in Thailand

NASA Astrophysics Data System (ADS)

Jomdecha, C.; Jirarungsatian, C.; Methong, W.; Poopat, B.

This chapter presents the status of using natural gas cylinders (CNG/NGV) and acoustic emission (AE) in Thailand. During the period from 2006 to 2013, more than 600,000 CNG cylinder units for vehicles were installed and used for transportation, cars, and trucks in Thailand. The number of cylinder units will be tentatively increased in the future due to the increase in gasoline price. Due to the use of high-pressurization equipment in public, the issue of a risk to public safety has been raised. As of this writing, in 2013, the testing standard from the Thai Department of Energy Business recommends inspection every 5 years using effective inspection methods in order to guarantee safe usage of gas cylinders, including the AE method, following ISO 16148. Normally in Thailand, AE is used in research and petrochemical plants as a special technique. The main applications are testing of pressure vessels, aboveground storage tanks, and university research. Few companies are available to conduct AE for testing natural gas cylinders due to the limited safety of the high-pressure operation and AE equipment and a lack of qualified AE personnel. To develop AE techniques, equipment, procedures, and acceptance criteria of natural gas cylinders are the main focus of AE personnel in Thailand. A desired achievement for current development is for natural gas cylinder testing, which can be applied in field tests and supported by a national testing standard.

A different approach on the onset of separation in the flow around a circular cylinder

NASA Astrophysics Data System (ADS)

Malamataris, Nikolaos; Sarris, I.; Pazis, D.; Liakos, A.

2016-11-01

The onset of separation in the flow around a cylinder is revisited with new insight. The goal of the research is to compute the smallest Reynolds number where the separation actual occurs rather than computing small eddies and extrapolating to the value of the Reynolds number where separation may occur. To this purpose, an accurate home made code is designed with Galerkin finite elements. The computational domain is chosen as the laboratory experiments by Taneda. It is found that in all six different choices of Taneda's diameters of the cylinders he used, separation is not observed for Re < 6 . 1 . Actually, separation is computed in all of his six cases for Re = 6 . 14 . Images of this smallest eddy are shown for the first time where all characteristics of eddies are recognisable (vortex centre, separation length etc). The vorticity of the flow is computed along the cylinder surface and it is shown that, at separation, vorticity changes sign. Byproducts of this research is the computation of the drag coefficient for Reynolds numbers starting from 1 .10-5 up to 40. In addition, the separation angle (point where vorticity changes sign) is computed for 6 . 14 <= Re <= 40 . This research aims to be the most thorough work done on that subject so far.

Growth behavior of surface cracks in the circumferential plane of solid and hollow cylinders

NASA Technical Reports Server (NTRS)

Forman, R. G.; Shivakumar, V.

1986-01-01

Experiments were conducted to study the growth behavior of surface fatigue cracks in the circumferential plane of solid and hollow cylinders. In the solid cylinders, the fatigue cracks were found to have a circular arc crack front with specific upper and lower limits to the arc radius. In the hollow cylinders, the fatigue cracks were found to agree accurately with the shape of a transformed semiellipse. A modification to the usual nondimensionalization expression used for surface flaws in flat plates was found to give correct trends for the hollow cylinder problem.

Effect of Free Stream Turbulence on Flow Past a Circular Cylinder at Low Reynolds Numbers

NASA Astrophysics Data System (ADS)

Kumar, Vinoth; Singh, Mrityunjay; Thangadurai, Murugan; Chatterjee, P. K.

2018-01-01

Circular cylinders experiencing different upstream flow conditions have been studied for low Reynolds numbers using hot-wire anemometry and smoke flow visualizations. The upstream condition of the cylinder in the test section is varied using a wire mesh placed at the entrance of the test section. The Reynolds number is varied by varying the diameter of the cylinder and the mean velocity in the test section. Smooth cylinders of diameter varying from 1.25 to 25 mm are used in the present study. A multi-channel hot-wire anemometry is used for measuring the fluctuating velocities in the test section and the wake behind the cylinder. The sectional views of the wake behind the cylinder are obtained using a 4 MP CCD camera, 200 mJ pulsed laser and a fog generator. The flow quality in the test section is examined using higher order turbulence statistics. The effect of free stream turbulence levels and their frequencies on wake structures and the shedding frequencies of circular cylinders are studied in detail. It has been observed that the alteration in wake structure and the shedding frequency depend strongly on the frequencies and the amplitudes of upstream disturbances besides the diameter of the circular cylinder.

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.

Stability of plasma cylinder with current in a helical plasma flow

NASA Astrophysics Data System (ADS)

Leonovich, Anatoly S.; Kozlov, Daniil A.; Zong, Qiugang

2018-04-01

Stability of a plasma cylinder with a current wrapped by a helical plasma flow is studied. Unstable surface modes of magnetohydrodynamic (MHD) oscillations develop at the boundary of the cylinder enwrapped by the plasma flow. Unstable eigenmodes can also develop for which the plasma cylinder is a waveguide. The growth rate of the surface modes is much higher than that for the eigenmodes. It is shown that the asymmetric MHD modes in the plasma cylinder are stable if the velocity of the plasma flow is below a certain threshold. Such a plasma flow velocity threshold is absent for the symmetric modes. They are unstable in any arbitrarily slow plasma flows. For all surface modes there is an upper threshold for the flow velocity above which they are stable. The helicity index of the flow around the plasma cylinder significantly affects both the Mach number dependence of the surface wave growth rate and the velocity threshold values. The higher the index, the lower the upper threshold of the velocity jump above which the surface waves become stable. Calculations have been carried out for the growth rates of unstable oscillations in an equilibrium plasma cylinder with current serving as a model of the low-latitude boundary layer (LLBL) of the Earth's magnetic tail. A tangential discontinuity model is used to simulate the geomagnetic tail boundary. It is shown that the magnetopause in the geotail LLBL is unstable to a surface wave (having the highest growth rate) in low- and medium-speed solar wind flows, but becomes stable to this wave in high-speed flows. However, it can remain weakly unstable to the radiative modes of MHD oscillations.

Pulsatile Flow Across a Cylinder--An Investigation of Flow in a Total Artificial Lung

NASA Astrophysics Data System (ADS)

Lin, Yu-Chun

2005-11-01

The effect of pulsatility on flow across a single cylinder has been examined experimentally using particle image velocimetry. This work is motivated by the ongoing development of a total artificial lung (TAL), a device which would serve as a bridge to lung transplant. The prototype TAL consists of hollow microfibers through which oxygen-rich gas flows and blood flows around. Flow through the device is provided entirely by right heart and, therefore, is puslatile. The Peclet number of the flow is large and consequently the development of secondary flow affects the resulting gas exchange. The effects of frequency and average flow rate of pulsatile flow around a cylinder were investigated experimentally in a water tunnel and some of the results were compared with preliminary numerical results. Vortices developed behind the cylinder at lower Reynolds numbers in pulsatile flow than steady flow. The results indicate that there are critical values of the Reynolds number between 3 to 5 and Stokes numbers of 0.22, below which vortices were not observed. The findings suggest that higher Stokes and Reynolds numbers within the device could enhance vortex formation. However, this enhanced gas exchange could be at the expense of higher device resistance and increased likelihood of blood trauma. Intelligent TAL design will require consideration of these effects. This work is supported by NIH grant HL69420.

The effect of preignition on cylinder temperatures, pressures, power output, and piston failures

NASA Technical Reports Server (NTRS)

Corrington, Lester C; Fisher, William F

1947-01-01

An investigation was conducted using a cylinder of a V-type liquid-cooled engine to observe the behavior of the cylinder when operated under preignition conditions. Data were recorded that showed cylinder-head temperatures, time of ignition, engine speed, power output, and change in maximum cylinder pressure as a function of time as the engine entered preignition and was allowed to operate under preignition conditions for a short time. The effects of the following variables on the engine behavior during preignition were investigated: fuel-air ratio, power level, aromatic content of fuel, engine speed, mixture temperature, and preignition source. The power levels at which preignition would cause complete piston failure for the selected engine operating conditions and the types of failure encountered when using various values of clearance between the piston and cylinder barrel were determined. The fuels used had performance numbers high enough to preclude any possibility of knock throughout the test program.

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…

49 CFR 178.38 - Specification 3B seamless steel cylinders.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., and service pressure. A DOT 3B cylinder is seamless steel cylinder with a water capacity (nominal) of... permitted in paragraph (d) of this section. (f) Wall thickness. The wall stress may not exceed 24,000 psi.... Calculation must be made by the following formula: S = [P(1.3D2+0.4d2)]/(D2−d2) Where: S = wall stress in psi...

49 CFR 178.65 - Specification 39 non-reusable (non-refillable) cylinders.

Code of Federal Regulations, 2013 CFR

2013-10-01

...) Material; steel or aluminum. The cylinder must be constructed of either steel or aluminum conforming to the following requirements: (1) Steel. (i) The steel analysis must conform to the following: Ladle analysis... percent .05 .06 (ii) For a cylinder made of seamless steel tubing with integrally formed ends, hot drawn...

49 CFR 178.65 - Specification 39 non-reusable (non-refillable) cylinders.

Code of Federal Regulations, 2010 CFR

2010-10-01

...) Material; steel or aluminum. The cylinder must be constructed of either steel or aluminum conforming to the following requirements: (1) Steel. (i) The steel analysis must conform to the following: Ladle analysis... percent .05 .06 (ii) For a cylinder made of seamless steel tubing with integrally formed ends, hot drawn...

49 CFR 178.65 - Specification 39 non-reusable (non-refillable) cylinders.

Code of Federal Regulations, 2014 CFR

2014-10-01

...) Material; steel or aluminum. The cylinder must be constructed of either steel or aluminum conforming to the following requirements: (1) Steel. (i) The steel analysis must conform to the following: Ladle analysis... percent .05 .06 (ii) For a cylinder made of seamless steel tubing with integrally formed ends, hot drawn...

49 CFR 178.65 - Specification 39 non-reusable (non-refillable) cylinders.

Code of Federal Regulations, 2012 CFR

2012-10-01

...) Material; steel or aluminum. The cylinder must be constructed of either steel or aluminum conforming to the following requirements: (1) Steel. (i) The steel analysis must conform to the following: Ladle analysis... percent .05 .06 (ii) For a cylinder made of seamless steel tubing with integrally formed ends, hot drawn...

Gas storage cylinder formed from a composition containing thermally exfoliated graphite

NASA Technical Reports Server (NTRS)

Aksay, Ilhan A. (Inventor); Prud'Homme, Robert K. (Inventor)

2012-01-01

A gas storage cylinder or gas storage cylinder liner, formed from a polymer composite, containing at least one polymer and a modified graphite oxide material, which is a thermally exfoliated graphite oxide with a surface area of from about 300 m(exp 2)/g to 2600 m(exp 2)2/g.

Relation between the Fluctuating Wall Pressure and the Turbulent Structure of a Boundary Layer on a Cylinder in Axial Flow

DTIC Science & Technology

1993-08-12

Shop for their expert assistance during thze design ard development ur the wind tunnel and experimental apparatus; Drs. Alan L. Kistler, Seth Lichter...vertical wind tunnel was designed and built for this research. I With the test section in a vertical orientation, gravity effects leading to cylinder sag...were eliminated. The overall design and layout of the wind tunnel, as well as specific design features incorporated into the wind tunnel to satisfy

Rotating Cylinder Treatment System Demonstration (Presentation)

EPA Science Inventory

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

Engine cylinder pressure reconstruction using crank kinematics and recurrently-trained neural networks

NASA Astrophysics Data System (ADS)

Bennett, C.; Dunne, J. F.; Trimby, S.; Richardson, D.

2017-02-01

A recurrent non-linear autoregressive with exogenous input (NARX) neural network is proposed, and a suitable fully-recurrent training methodology is adapted and tuned, for reconstructing cylinder pressure in multi-cylinder IC engines using measured crank kinematics. This type of indirect sensing is important for cost effective closed-loop combustion control and for On-Board Diagnostics. The challenge addressed is to accurately predict cylinder pressure traces within the cycle under generalisation conditions: i.e. using data not previously seen by the network during training. This involves direct construction and calibration of a suitable inverse crank dynamic model, which owing to singular behaviour at top-dead-centre (TDC), has proved difficult via physical model construction, calibration, and inversion. The NARX architecture is specialised and adapted to cylinder pressure reconstruction, using a fully-recurrent training methodology which is needed because the alternatives are too slow and unreliable for practical network training on production engines. The fully-recurrent Robust Adaptive Gradient Descent (RAGD) algorithm, is tuned initially using synthesised crank kinematics, and then tested on real engine data to assess the reconstruction capability. Real data is obtained from a 1.125 l, 3-cylinder, in-line, direct injection spark ignition (DISI) engine involving synchronised measurements of crank kinematics and cylinder pressure across a range of steady-state speed and load conditions. The paper shows that a RAGD-trained NARX network using both crank velocity and crank acceleration as input information, provides fast and robust training. By using the optimum epoch identified during RAGD training, acceptably accurate cylinder pressures, and especially accurate location-of-peak-pressure, can be reconstructed robustly under generalisation conditions, making it the most practical NARX configuration and recurrent training methodology for use on production engines.

Analysis of an Indirect Neutron Signature for Enhanced UF6 Cylinder Verification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kulisek, Jonathan A.; McDonald, Benjamin S.; Smith, Leon E.

2017-02-21

The International Atomic Energy Agency (IAEA) currently uses handheld gamma-ray spectrometers combined with ultrasonic wall-thickness gauges to verify the declared enrichment of uranium hexafluoride (UF6) cylinders. The current method provides relatively low accuracy for the assay of 235U enrichment, especially for natural and depleted UF6. Furthermore, the current method provides no capability to assay the absolute mass of 235U in the cylinder due to the localized instrument geometry and limited penetration of the 186-keV gamma-ray signature from 235U. Also, the current verification process is a time-consuming component of on-site inspections at uranium enrichment plants. Toward the goal of a more-capablemore » cylinder assay method, the Pacific Northwest National Laboratory has developed the hybrid enrichment verification array (HEVA). HEVA measures both the traditional 186-keV direct signature and a non-traditional, high-energy neutron-induced signature (HEVANT). HEVANT enables full-volume assay of UF6 cylinders by exploiting the relatively larger mean free paths of the neutrons emitted from the UF6. In this work, Monte Carlo modeling is used as the basis for characterizing HEVANT in terms of the individual contributions to HEVANT from nuclides and hardware components. Monte Carlo modeling is also used to quantify the intrinsic efficiency of HEVA for neutron detection in a cylinder-assay geometry. Modeling predictions are validated against neutron-induced gamma-ray spectra from laboratory measurements and a relatively large population of Type 30B cylinders spanning a range of enrichments. Implications of the analysis and findings on the viability of HEVA for cylinder verification are discussed, such as the resistance of the HEVANT signature to manipulation by the nearby placement of neutron-conversion materials.« less

Comparative Performance of Engines Using a Carburetor, Manifold Injection, and Cylinder Injection

NASA Technical Reports Server (NTRS)

Schey, Oscar W; Clark, J Denny

1939-01-01

The comparative performance was determined of engines using three methods of mixing the fuel and the air: the use of a carburetor, manifold injection, and cylinder injection. The tests were made of a single-cylinder engine with a Wright 1820-G air-cooled cylinder. Each method of mixing the fuel and the air was investigated over a range of fuel-air ratios from 0.10 to the limit of stable operation and at engine speeds of 1,500 and 1,900 r.p.m. The comparative performance with a fuel-air ratio of 0.08 was investigated for speeds from 1,300 to 1,900 r.p.m. The results show that the power obtained with each method closely followed the volumetric efficiency; the power was therefore the highest with cylinder injection because this method had less manifold restriction. The values of minimum specific fuel consumption obtained with each method of mixing of fuel and air were the same. For the same engine and cooling conditions, the cylinder temperatures are the same regardless of the method used for mixing the fuel and the air.

Genetic algorithm based active vibration control for a moving flexible smart beam driven by a pneumatic rod cylinder

NASA Astrophysics Data System (ADS)

Qiu, Zhi-cheng; Shi, Ming-li; Wang, Bin; Xie, Zhuo-wei

2012-05-01

A rod cylinder based pneumatic driving scheme is proposed to suppress the vibration of a flexible smart beam. Pulse code modulation (PCM) method is employed to control the motion of the cylinder's piston rod for simultaneous positioning and vibration suppression. Firstly, the system dynamics model is derived using Hamilton principle. Its standard state-space representation is obtained for characteristic analysis, controller design, and simulation. Secondly, a genetic algorithm (GA) is applied to optimize and tune the control gain parameters adaptively based on the specific performance index. Numerical simulations are performed on the pneumatic driving elastic beam system, using the established model and controller with tuned gains by GA optimization process. Finally, an experimental setup for the flexible beam driven by a pneumatic rod cylinder is constructed. Experiments for suppressing vibrations of the flexible beam are conducted. Theoretical analysis, numerical simulation and experimental results demonstrate that the proposed pneumatic drive scheme and the adopted control algorithms are feasible. The large amplitude vibration of the first bending mode can be suppressed effectively.

On the development of lift and drag in a rotating and translating cylinder

NASA Astrophysics Data System (ADS)

Martin-Alcantara, Antonio; Sanmiguel-Rojas, Enrique; Fernandez-Feria, Ramon

2014-11-01

The two-dimensional flow around a rotating cylinder is investigated numerically using a vorticity forces formulation with the aim of analyzing the flow structures, and their evolutions, that contribute to the lift and drag forces on the cylinder. The Reynolds number, based on the cylinder diameter and steady free-stream speed, considered is Re = 200 , while the non-dimensional rotation rate (ratio of the surface speed and free-stream speed) selected were α = 1 and 3. For α = 1 the wake behind the cylinder for the fully developed flow is oscillatory due to vortex shedding, and so are the lift and drag forces. For α = 3 the fully developed flow is steady with constant (high) lift and (low) drag. Each of these cases is considered in two different transient problems, one with angular acceleration of the cylinder and constant speed, and the other one with translating acceleration of the cylinder and constant rotation. Special attention is paid to explaining the mechanisms of vortex shedding suppression for high rotation (when α = 3) and its relation to the mechanisms by which the lift is enhanced and the drag is almost suppressed when the fully developed flow is reached. Supported by the Ministerio de Economia y Competitividad of Spain Grant No. DPI2013-40479-P.

Dynamics of spherical metallic particles in cylinder electrostatic separators/purifiers.

PubMed

Lu, Hong-Zhou; Li, Jia; Guo, Jie; Xu, Zhen-Ming

2008-08-15

This paper presents a theoretical analysis of the dynamics of spherical metallic particles in electrostatic separators/purifiers (ESPs). The particle equations of motion are numerically solved in two dimensions using a computational algorithm. The ESPs consist of a pair of conductor cylinder electrodes. The upper cylinder is energized by HVdc, while the lower one is grounded and fixed horizontally on a revolvable axis. Some phenomena and aspects of separation process are explained and depicted including lifting off, impact, "motion collapse" and "sudden bouncing". The results reveal that the several phenomena depend on initial position, radius and density of the particle, curvature of the cylinder electrodes, distance between the electrodes and amplitude of the applied voltage. Optimization of the parameters is presented in order to get better separation/purification processes.

Integrated approach for stress analysis of high performance diesel engine cylinder head

NASA Astrophysics Data System (ADS)