The Pulsatile Flow Measurement by Electromagnetic Flowmeter; The Relation between the Accuracy and the Uniformity of the Magnetic Field

1966 ◽  
Vol 2 (2) ◽  
pp. 152-161 ◽  
Author(s):  
Hiroshi KANAI
Keyword(s):  
Magnetic Field ◽  
Pulsatile Flow ◽  
Flow Measurement ◽  
Electromagnetic Flowmeter ◽  
The Magnetic Field

Magnetic Targeting of Particle Transport Under Pulsatile Flow

2006 ◽  
Author(s):  
Alicia Williams ◽  
Ashok Sinha ◽  
Pavlos Vlachos ◽  
Ishwar K. Puri
Keyword(s):  
Magnetic Field ◽  
Pulsatile Flow ◽  
Magnetic Particles ◽  
Colloidal Suspension ◽  
Magnetic Field Gradient ◽  
Colloidal Suspensions ◽  
Glass Tube ◽  
Superparamagnetic Nanoparticles ◽  
Magnetic Drug Targeting ◽  
The Magnetic Field

Magnetic Drug Targeting (MDT) has been shown to be a promising technique to effectively deliver medicinal drugs via functionalized [1] magnetic particles to target sites during the treatment of cancer and other diseases [2,3,4]. In this paper, we investigate the interaction of steady and pulsatile flows injected with a ferrofluid, which is a colloidal suspension of superparamagnetic nanoparticles in a glass tube under the influence of a magnetic field. Ferrofluids are colloidal suspensions of single domain magnetic nanoparticles that are of the order of 10 nm in diameter. In this experiment, the ferrofluid particles were directed to a particular region of interest within a 10 mm diameter glass vessel by means of an applied localized magnetic field that originated outside of the vessel. The magnetic field was generated using a rare earth sintered permanent magnet which produced the magnetic field gradient required for inducing a body force on the volume of the ferrofluid. The experimental results reveal flows with rich dynamical phenomena. The aggregation of the ferrofluid produces a self-assembled hemispherical structure which dynamically interacts with the host flow. The aggregation generates an occlusion creating a flow field that is similar to that past an obstruction. However, since the structure itself is of a fluidic nature, it is subject to shear forces caused by the host fluid. In addition, the wake of the flow behind the aggregation creates vortices which are critical to study the stability of the ferrofluid aggregate. This paper presents a detailed investigation of the dynamics of the flow using Time-Resolved Digital Particle Image Velocimetry. To the best of the authors’ knowledge, these are the first quantitative, spatiotemporally resolved measurements documenting the interaction of a host fluid with a ferrofluid aggregate under steady or pulsatile flow conditions.

Dynamic accuracy of the electromagnetic flowmeter

1965 ◽  
Vol 20 (1) ◽  
pp. 142-147 ◽  
Author(s):  
M. F. O'Rourke
Keyword(s):  
Magnetic Field ◽  
Pulsatile Flow ◽  
Output Signal ◽  
Oscillatory Flow ◽  
Electromagnetic Flowmeter ◽  
Sine Wave ◽  
Dynamic Calibration ◽  
Phase Lag ◽  
Dynamic Accuracy ◽  
Sinusoidal Flow

Dynamic calibration of electromagnetic flowmeters was performed by resolving the output signal when sinusoidal flow of known characteristics was pumped through the probe. In two instruments amplitude and phase were found to be frequency dependent in the range 0–20 cycle/sec; the magnitude of these effects was not insignificant as many have assumed. In a sine wave instrument using a variety of probes, both amplitude and phase increased linearly with frequency: the former increasing by 0.57% per cycle per second, the latter by 3.6° per cycle per second. In the square wave flowmeter at 0 damping, amplitude decreased significantly above 5 cycle/sec, while phase lag increased by 4.9° per cycle per second. These effects are concluded to be due to the output filtering network. In the sine wave instrument it was demonstrated that magnetic field nonuniformity within the probe did not alter the accuracy in recording steady or oscillatory flow. It was thus possible to construct a small short flowmeter probe having narrow electromagnet coils, and it is expected that this probe should cause minimal interference to pulsatile flow patterns. magnetic fields flowmeter probes; frequency-response flowmeter Submitted on April 16, 1964

The theory of induced voltage electromagnetic flowmeters

1970 ◽  
Vol 43 (3) ◽  
pp. 577-590 ◽  
Author(s):  
M. K. Bevir
Keyword(s):  
Magnetic Field ◽  
Velocity Profile ◽  
Flow Pattern ◽  
Flow Rate ◽  
Output Voltage ◽  
Electromagnetic Flowmeter ◽  
Weight Vector ◽  
Induced Voltage ◽  
Necessary And Sufficient ◽  
The Magnetic Field

The performance of an electromagnetic flowmeter head is assessed in terms of a weight vector W such that the output voltage ∝ ∫ v. Wdτ, where v is the velocity and τ the flowmeter volume. The condition curl W = 0 with W → 0 at ∞ is shown to be necessary and sufficient for the velocity to depend only on the flow rate and not on the flow pattern. A class of such ‘ideal’ meters is described. It is shown that meters with point electrodes can never be ideal but may, with considerable complication of the magnetic field, be made immune to asymmetric velocity-profile variations if the flow is rectilinear.

scholarly journals THE MEASUREMENT OF TIDAL WATER TRANSPORT IN CHANNELS

1970 ◽  
Vol 1 (12) ◽  
pp. 114
Author(s):  
R.E. Klein
Keyword(s):  
Magnetic Field ◽  
Electric Potential ◽  
Flow Measurement ◽  
Potential Difference ◽  
Measured Signal ◽  
Electric Conductor ◽  
Measuring Systems ◽  
The Earth ◽  
Tidal Water ◽  
The Magnetic Field

For the electromagnetic flow measurement in straits, channels etc use is made of the electric potential difference between two points m the bottom, near the moving water. The potential difference can be put down to natural causes the water is an electric conductor and moves m the magnetic field of the earth There are a number of quantities and variables that are of importance for the measured signal Beside this, the measurement is above all a matter of eliminating some disturbances Information about the two measuring systems as applied m The Netherlands is given m this article.

Observing the galactic magnetic field

1967 ◽  
Vol 31 ◽  
pp. 375-380
Author(s):  
H. C. van de Hulst
Keyword(s):  
Magnetic Field ◽  
Fair Agreement ◽  
Solar Neighbourhood ◽  
Galactic Magnetic Field ◽  
The Magnetic Field

Various methods of observing the galactic magnetic field are reviewed, and their results summarized. There is fair agreement about the direction of the magnetic field in the solar neighbourhood:l= 50° to 80°; the strength of the field in the disk is of the order of 10-5gauss.

Evolution of Large-Scale Coronal Structures

1994 ◽  
Vol 144 ◽  
pp. 29-33
Author(s):  
P. Ambrož
Keyword(s):  
Magnetic Field ◽  
Field Line ◽  
Large Scale ◽  
Coronal Magnetic Field ◽  
Source Surface ◽  
Solar Cycles ◽  
Characteristic Relationship ◽  
The Magnetic Field ◽  
Coronal Structures

AbstractThe large-scale coronal structures observed during the sporadically visible solar eclipses were compared with the numerically extrapolated field-line structures of coronal magnetic field. A characteristic relationship between the observed structures of coronal plasma and the magnetic field line configurations was determined. The long-term evolution of large scale coronal structures inferred from photospheric magnetic observations in the course of 11- and 22-year solar cycles is described.Some known parameters, such as the source surface radius, or coronal rotation rate are discussed and actually interpreted. A relation between the large-scale photospheric magnetic field evolution and the coronal structure rearrangement is demonstrated.

Emergence of Twisted Magnetic Flux Related Sigmoidal Brightening

2000 ◽  
Vol 179 ◽  
pp. 263-264
Author(s):  
K. Sundara Raman ◽  
K. B. Ramesh ◽  
R. Selvendran ◽  
P. S. M. Aleem ◽  
K. M. Hiremath
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Magnetic Flux ◽  
Ultra Violet ◽  
Active Regions ◽  
Morphological Properties ◽  
Energy Storage And Conversion ◽  
The Sun ◽  
X Rays ◽  
The Magnetic Field

Extended AbstractWe have examined the morphological properties of a sigmoid associated with an SXR (soft X-ray) flare. The sigmoid is cospatial with the EUV (extreme ultra violet) images and in the optical part lies along an S-shaped Hαfilament. The photoheliogram shows flux emergence within an existingδtype sunspot which has caused the rotation of the umbrae giving rise to the sigmoidal brightening.It is now widely accepted that flares derive their energy from the magnetic fields of the active regions and coronal levels are considered to be the flare sites. But still a satisfactory understanding of the flare processes has not been achieved because of the difficulties encountered to predict and estimate the probability of flare eruptions. The convection flows and vortices below the photosphere transport and concentrate magnetic field, which subsequently appear as active regions in the photosphere (Rust & Kumar 1994 and the references therein). Successive emergence of magnetic flux, twist the field, creating flare productive magnetic shear and has been studied by many authors (Sundara Ramanet al.1998 and the references therein). Hence, it is considered that the flare is powered by the energy stored in the twisted magnetic flux tubes (Kurokawa 1996 and the references therein). Rust & Kumar (1996) named the S-shaped bright coronal loops that appear in soft X-rays as ‘Sigmoids’ and concluded that this S-shaped distortion is due to the twist developed in the magnetic field lines. These transient sigmoidal features tell a great deal about unstable coronal magnetic fields, as these regions are more likely to be eruptive (Canfieldet al.1999). As the magnetic fields of the active regions are deep rooted in the Sun, the twist developed in the subphotospheric flux tube penetrates the photosphere and extends in to the corona. Thus, it is essentially favourable for the subphotospheric twist to unwind the twist and transmit it through the photosphere to the corona. Therefore, it becomes essential to make complete observational descriptions of a flare from the magnetic field changes that are taking place in different atmospheric levels of the Sun, to pin down the energy storage and conversion process that trigger the flare phenomena.

On the Configuration of the Magnetic Field of β CrB

1976 ◽  
Vol 32 ◽  
pp. 613-622
Author(s):  
I.A. Aslanov ◽  
Yu.S. Rustamov
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Radial Velocity ◽  
Magnetic Field Strength ◽  
Complex Shape ◽  
Rotation Period ◽  
Field Variation ◽  
Magnetic Field Variation ◽  
Secular Variations ◽  
The Magnetic Field

SummaryMeasurements of the radial velocities and magnetic field strength of β CrB were carried out. It is shown that there is a variability with the rotation period different for various elements. The curve of the magnetic field variation measured from lines of 5 different elements: FeI, CrI, CrII, TiII, ScII and CaI has a complex shape specific for each element. This may be due to the presence of magnetic spots on the stellar surface. A comparison with the radial velocity curves suggests the presence of a least 4 spots of Ti and Cr coinciding with magnetic spots. A change of the magnetic field with optical depth is shown. The curve of the Heffvariation with the rotation period is given. A possibility of secular variations of the magnetic field is shown.

Materials for Electron Beam Information Storage

1969 ◽  
Vol 27 ◽  
pp. 152-153 ◽  
Author(s):  
D. E. Speliotis
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Recent Literature ◽  
Electron Beams ◽  
Information Storage ◽  
The Subject ◽  
The Magnetic Field

The interaction of electron beams with a large variety of materials for information storage has been the subject of numerous proposals and studies in the recent literature. The materials range from photographic to thermoplastic and magnetic, and the interactions with the electron beam for writing and reading the information utilize the energy, or the current, or even the magnetic field associated with the electron beam.

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