Narrow Pipe Research Articles

2P4-7 Exfoliation and Guidance of Adhered Fine Particles Using High-Intensity Aerial Ultrasonic Waves with Narrow Pipe(Poster Session)

2P4-7 Exfoliation and Guidance of Adhered Fine Particles Using High-Intensity Aerial Ultrasonic Waves with Narrow Pipe(Poster Session)

2A1-P02 繰り出し式柔軟流体アクチュエータによる狭隘地形内の移動探査ロボット : 第3 報:受動蛇行を利用した鉛直管路内の移動(特殊移動ロボット(1))

2A1-P02 繰り出し式柔軟流体アクチュエータによる狭隘地形内の移動探査ロボット : 第3 報:受動蛇行を利用した鉛直管路内の移動(特殊移動ロボット(1))

New methods for interpretation of magnetic vector and gradient tensor data I: eigenvector analysis and the normalised source strength

Acquisition of magnetic gradient tensor data is likely to become routine in the near future. New methods for inverting gradient tensor surveys to obtain source parameters have been developed for several elementary, but useful, models. These include point dipole (sphere), vertical line of dipoles (narrow vertical pipe), line of dipoles (horizontal cylinder), thin dipping sheet, and contact models. A key simplification is the use of eigenvalues and associated eigenvectors of the tensor. The normalised source strength (NSS), calculated from the eigenvalues, is a particularly useful rotational invariant that peaks directly over 3D compact sources, 2D compact sources, thin sheets and contacts, and is independent of magnetisation direction. In combination the NSS and its vector gradient determine source locations uniquely. NSS analysis can be extended to other useful models, such as vertical pipes, by calculating eigenvalues of the vertical derivative of the gradient tensor. Inversion based on the vector gradient of the NSS over the Tallawang magnetite deposit obtained good agreement between the inferred geometry of the tabular magnetite skarn body and drill hole intersections. Besides the geological applications, the algorithms for the dipole model are readily applicable to the detection, location and characterisation (DLC) of magnetic objects, such as naval mines, unexploded ordnance, shipwrecks, archaeological artefacts, and buried drums.

Movement of a Cableless In-Piping Magnetic Actuator With a New Propulsion Module

It is important to inspect pipes used in nuclear power plants and reactors. A number of studies have investigated various locomotion mechanisms of robots controlled by electric cables in pipes. A cableless actuator capable of movement in narrow pipes of less than 15 mm has not yet been developed. The present paper proposes a novel cableless magnetic actuator with a propulsion module that exhibits a high thrusting force. The effect of the magnetic forces generated by two different propulsion modules on the movement of the cableless actuator was investigated theoretically and experimentally. The proposed actuator includes an electrical inverter that directly transforms DC from button batteries into AC. Experimental results indicate that the proposed actuator can move vertically at a speed of 225 mm/s, using the power provided by 10 button batteries when pulling no load mass. This cableless magnetic actuator has several possible applications, including inspection of small pipes.

Agglomeration kinetics of submicron barium sulfate precipitates

Unwanted agglomeration, especially in highly concentrated submicron and nano- particle suspensions, can rapidly change the physical product properties of produced particles. Knowledge of the agglomeration kinetics and mechanisms is crucial to achieve control over this secondary sub-process of particle formation.To obtain this kinetics a new measurement method is presented to monitor the shear induced agglomeration behavior of submicron barium sulfate particles while passing a narrow pipe. The residence time, i.e. agglomeration time was varied with the pipe length at constant suspension flow rate. Before measurement, the particle suspension was stabilized by rapid mixing with a dispersing agent. Based on measured agglomerate size distribution, the agglomeration behavior is discussed in terms of non-turbulent flow in a narrow pipe.Barium sulfate agglomeration in a simple shear flow could be monitored on submicron scale. The effect of steric stabilization to reduce or prevent agglomeration was shown and quantified. The controlling mechanism for agglomeration in a pipe is identified based on the hydrodynamic characteristics. The adhesion probability was found to decrease with agglomerate size.

Clutter‐adaptation of bat species predicts their use of under‐motorway passageways of contrasting sizes – a natural experiment

AbstractBat populations may be vulnerable to the barrier impacts of roads, including habitat restriction and traffic mortality. Under‐road passageways may reduce these impacts, but little is known about the ecological factors influencing their use by bats. The study area provided a natural experimental design, in that adjacent under‐motorway passageways had contrasting dimensions (two long, narrow drainage pipes within <1 km of a large underpass for a minor road), and local bat species had contrasting functional and morphological adaptations. We predicted that inter‐species differences in flight capability and sensory perception would influence bat use of passageways. All‐night acoustic recordings of bat activity inside passageways (52 nights) indicated clear guild‐specific responses to passageway dimensions. Only Rhinolophus hipposideros, Myotis nattereri and Plecotus auritus flew through the narrow drainage pipes. These species are adapted for flight and foraging in cluttered airspace, in terms of wing morphology and echolocation signal design. Edge‐space species (Pipistrellus pipistrellus, Pipistrellus pygmaeus) were highly active in the area but never flew through the narrow pipes. All species, except the open‐adapted Nyctalus leisleri, flew through the large underpass. Simultaneous recordings made above and below this underpass (16 nights) also indicated that species' tendency to cross over, rather than under, the structure was inversely related to the degree of clutter‐adaptation. If motorways are built through bat habitat, trade‐offs between optimal mitigation of impacts on protected bats and cost/engineering practicality are inevitable. Large underpasses are advisable where possible as they accommodate a wider range of species, and bats are less likely to fly over them. However, their construction is costly and is dependent on landscape topology. If the target species for mitigation are clutter‐adapted bats, our findings indicate that incorporation of a greater number of suitably located small tunnels into new roads may facilitate safe passage more effectively than fewer large underpasses.

2A2-O04 繰り出し式柔軟流体アクチュエータによる狭隘地形内の移動探査ロボット : 第2報 : 方向操舵手法(特殊移動ロボット(2))

2A2-O04 繰り出し式柔軟流体アクチュエータによる狭隘地形内の移動探査ロボット : 第2報 : 方向操舵手法(特殊移動ロボット(2))

1P1-R10 空気圧人工筋肉を用いた曲管・細管走行可能な蠕動運動型工業用内視鏡ロボットの開発(バイオロボティクス)

1P1-R10 空気圧人工筋肉を用いた曲管・細管走行可能な蠕動運動型工業用内視鏡ロボットの開発(バイオロボティクス)

Magnetic Actuator Group of Globular Type Capable of Free Movement in a Complex Pipe

Finding damage inside pipes is important for the inspection of complex pipes used in nuclear power plants and chemical plants. A number of studies have investigated the mechanisms of an actuator with an electric cable to provide locomotion through various devices in complex pipes. An in-pipe robot capable of movement in narrow complex pipes has not yet been developed. In the present paper, we propose a globular magnetic actuator group that exhibits a very high thrust force and is capable of free reversible motion in complex pipes. Two actuators of the same size and characteristics are coupled by the magnetic connection method, which generates almost no mechanical loss. The globular magnetic actuator group capable of reversible motion through elongation and contraction of eight shape-memory-alloy (SMA) coils was fabricated. Experimental results indicate that the prototype actuator group is able to climb at a rate of 29 mm/s in a straight pipe while pulling a load mass of 48 g.

2 자유도 작동기 모듈로 구성된 뱀 로봇 개발

This article describes a snake robot with 2-DOF actuator modules. The 2-DOF actuator modules make the snake robot move in the 3D space so that the snake robot can cross obstacles and rough terrain. Each 2-DOF actuator module is designed to have high torque output and an embedded controller. A cross bracket connecting the modules is designed be able to support the weight of two actuator modules. The developed snake robot shows 3-D motions such as side winding, standing/monitoring, and can climb in a narrow pipe with high torque modules. The snake robot moves fast with passive wheels in a plane while crossing obstacles.

Interaction of Cu and plastic plasmas as a method of forming laser produced Cu plasma streams with a narrow jet or pipe geometry

This brief communication is aimed at investigations of interaction of axially symmetrical light (plastic) plasma with heavy (copper) plasma. The use of axially symmetrical target compositions consisting of materials with low and high atomic numbers makes it possible to create different plasma stream configurations (e.g., very narrow jet or pipe). In the paper certain their applications are suggested.

2A2-L05 SMAアクチュエータを用いた蠕動運動による管内移動ロボット(特殊移動ロボット)

There are many various movements in the natural world. Peristalsis motion like an earthworm is useful to progress in any confined spaces. In this study, our purpose is development of earthworm robot which is useful to progress in the narrow pipe. An actuator of the earthworm robot was BioMetal Fiber (BMF series) which is one of the shape memory alloys. BMF, elongated at room temperature, becomes stiff and sharply contract when a current is fed through it. The mechanism of using BMF is lighter and smaller than any other mechanisms, such as DC motor, servo motor and air pressure.

Novel Globular Magnetic Actuator Group Capable of Free Movement in a Complex Pipe

Finding damage inside pipes is important for the inspection of complex pipes used in nuclear power plants and chemical plants. A number of studies have investigated the mechanisms of an actuator with an electric cable to provide locomotion through various devices in complex pipes. An in-pipe robot capable of movement in narrow complex pipes has not yet been developed. In the present paper, we propose a globular magnetic actuator group that exhibits a very high thrust force and is capable of free reversible motion in complex pipes. Two actuators of the same size and characteristics are coupled by the magnetic connection method, which generates almost no mechanical loss. The globular magnetic actuator group capable of reversible motion through elongation and contraction of eight shape-memory-alloy (SMA) coils was fabricated. Experimental results indicate that the prototype actuator group is able to climb at a rate of 29 mm/s in a straight pipe while pulling a load mass of 48 g. In addition, the average speeds for two patterns of movement in a complex pipe with several curved sections and step sections were measured. The prototype actuator group is able to move in a complex pipe at an average speed of over 30 mm/s. This actuator group has several possible applications, including inspection using a micro-camera and pipe maintenance.

Performance of Cableless Magnetic In-Piping Actuator Capable of High-Speed Movement by Means of Inertial Force

The present paper proposes a novel cableless magnetic actuator with a new propulsion module that exhibits a very high thrusting force. This actuator contains an electrical inverter that directly transforms DC from button batteries into AC. The electrical DC-AC inverter incorporates a mass-spring system, a reed switch, and a curved permanent magnet that switches under an electromagnetic force. The actuator is moved by the inertial force of the mass-spring system due to mechanical resonance energy. The experimental results show that the actuator is able to move upward at a speed of 19.7 mm/s when using 10 button batteries when pulling a 20 g load mass. This cableless magnetic actuator has several possible applications, including narrow pipe inspection and maintenance.

Localized Etching of a Polyimide Film by an Atmospheric-Pressure Radio Frequency Microplasma Excited by a 100-µm-φ Metal Pipe Electrode

Atmospheric-pressure He and Ar microplasmas (µ-plasmas) have been generated by a 14 MHz radio-frequency (RF) discharge using a metal narrow pipe electrode with an outer diameter of 100 µm. The metal pipe acts as both a powered electrode and a gas nozzle. The discharge mode changed from a corona discharge to a glow discharge and finally to a thermal spot arc discharge with decreasing discharge gap between the pipe electrode and the grounded plate as well as with increasing RF power. The Ar glow µ-plasma was applied to the localized etching of a polyimide film with a thickness of 0.025 mm in air ambient. The etched spot showed an isotropic profile having a gradual slope with a full width at half maximum of approximately 170 µm. The etching rate was approximately 3 µm/s at an RF power of 1.5 W. The optical emission spectrum exhibited second-positive N2 molecular bands and atomic oxygen lines (777 and 845 nm) as well as many Ar atomic lines. It appears that the energetic N2 molecules and UV photons radiated from the excitation states of N2 broke C–C and C–H bonds and then O radicals reacted with the hydrocarbon fragments to produce CO2 and H2O. Consequently, isotropic chemical etching was achieved.

Nonlinear and linear wave phenomena in narrow pipes

Phenomena arising in the course of wave propagation in narrow pipes are considered. For nonlinear waves described by the generalized Webster equation, a simplified nonlinear equation is obtained that allows for low-frequency geometric dispersion causing an asymmetric distortion of the periodic wave profile, which qualitatively resembles the distortion of a nonlinear wave in a diffracted beam. Tunneling of a wave through a pipe constriction is investigated. Possible applications of the phenomenon are discussed, and its relation to the problems of quantum mechanics because of the similarity of the basic equations of the Klein-Gordon and Schrodinger types is pointed out. The importance of studying the tunneling of nonlinear waves and broadband signals is indicated.

USE OF DIGITAL SIGNAL ANALYSIS TO IDENTIFY SLUG FLOW IN A NARROW VERTICAL PIPE

In the present study the conductivity probe technique has been adopted to investigate slug flow in a vertical narrow pipe of 0.012 m ID. Measurements have been made for air phase velocity varying from 0.05 to 7 m/s and water from 0.15 to 2 m/s. Several analyses of the random signals, namely PDF, FFT, and wavelet multi-resolution of the signal, have been performed. Different quantitative measures of the PDF and FFT curves as well the fluctuations at the different scales of the wavelet analysis have been used to identify the range of existence of the slug flow pattern. An objective flow pattern indicator has been developed on the basis of the measurement. The flow pattern indicator is effective in defining “pure” and “bubbly” slug flow and differentiating them from dispersed and annular pattern.

Model for density waves in gravity-driven granular flow in narrow pipes

A gravity-driven flow of grains through a narrow pipe in vacuum is studied by means of a one-dimensional model with two coefficients of restitution. Numerical simulations show clearly how density waves form when a strikingly simple criterion is fulfilled: that dissipation due to collisions between the grains and the walls of the pipe is greater per collision than that which stems from collisions between particles. Counterintuitively, the highest flow rate is observed when the number of grains per density wave grows large. We find strong indication that the number of grains per density wave always approaches a constant as the particle number tends to infinity, and that collapse to a single wave, which was often observed also in previous simulations, occurs because the number of grains is insufficient for multiple wave formation.

An appraisal of liquid–liquid slug flow in different pipe orientations

Gas–liquid slug flow occurs over a wide range of phase flow rates and in a variety of practical applications during gas–liquid two-phase flows. The range of slug flow increases further in narrow pipes (<0.0254 m), undulated pipelines, riser tube, etc. On the other hand, the past literature shows that slug flow is rarely observed for liquid–liquid cases. In the present study, an interest was felt to investigate whether liquid–liquid slug flow occurs in situations known for excessive slugging in gas–liquid cases. For this, experiments have been performed in narrow (0.012 m ID) vertical and horizontal pipes and an undulated pipeline of 0.0254 m internal diameter where the V-shaped undulation comprises of an uphill and a downhill section between two horizontal pipes. The studies have been performed for both peak and valley orientation of the undulation. Kerosene and water have been selected as the test fluids and the optical probe technique has been used to supplement visual observations especially at higher flow rates. The studies have revealed the existence of the slug flow pattern over a wide range of phase flow rates in all the three geometries. Interestingly, it has been noted that the introduction of an undulation induces flow patterns which bear a closer resemblance to gas–liquid flows as compared to liquid–liquid flows through a horizontal pipe of 0.0254 m diameter.

On necklaces with hard non-spherical beads

In spite of the fact that our world is three-dimensional, one-dimensional statistical models are important for a number of reasons. First, in some cases they are exactly solvable while their higher-dimensional counterparts are not. Consequently, the one-dimensional solutions may provide some insight into basic important mechanisms and useful approximation schemes. Then there are many instances where the description of a physical system as one-dimensional, or even better as quasi-one-dimensional, is quite realistic. In the present article two families of quasi-one-dimensional systems are presented. Although the two families are constructed to describe different physics, their basic mathematical structure is similar. The first family takes into the account the effect of hard core repulsion of non-spherical particles. It is prototyped by a necklace of hard non-spherical beads that are free to move along the necklace and to rotate about it. The second family takes into account the possibility of squeezing of hard objects, because the system is not strictly one-dimensional. This is prototyped by a system of hard objects confined to a narrow pipe with a diameter which is somewhat larger than the size of the objects but not large enough to allow changing the order of the objects along the pipe. The general treatment of such models is discussed and the exact configurational free energy is worked out for a specific example.