scholarly journals Reconstruction of German Coastal Defense Line in 1942-1944 and Search for Military Historical Heritage Objects. Bolshoi Tyuters Island. Data of Geophysical Methods and Excavations.

2021 ◽  
pp. 144-161
Author(s):  
Aleksandr L'vovich Borisik ◽  
Evgeniy Vladimirovich Pyatigorskiy
Keyword(s):  
Magnetic Field ◽  
Sand Dunes ◽  
Geophysical Methods ◽  
Observation System ◽  
Metal Debris ◽  
Coastal Defense ◽  
Historical Heritage ◽  
Short Time ◽  
High Degree ◽  
The Magnetic Field

The article describes the results of full-scale geophysical 2017-2018 studies conducted with the purpose of detecting military historical heritage objects on Bolshoy Tyuters Island. Sand dunes located in the eastern part of the island were studied in a short time by detailed magnetic exploration with an observation step of about 1 m. The most interesting anomalies of the magnetic field were investigated with the georadiolocation method. The processed results provided for mapping the anomalous magnetic field and creating georadiolocation sections and a dimensional relief model which demonstrate anomalies related to German defense and are promising for further excavations. The pinpoint excavations of the identified anomalies made it possible to explain their nature and discover objects of historical value at depths of up to 5 m. Despite high "contamination" of the dunes with metal debris, the use of geophysical methods with a dense observation system made it possible to detect a large number of objects of military historical heritage and significantly reduce the volume of excavations. Linking of the German positions archival scheme at hand additionally provided for comparing the location of the objects found with symbols made on it. After systematization and generalization of all the information obtained during 4 years of research on the island, it is possible to reconstruct the system of German defense in the area of sand dunes with a high degree of reliability.

scholarly journals A Novel Impedance Micro-Sensor for Metal Debris Monitoring of Hydraulic Oil

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 150
Author(s):  
Hongpeng Zhang ◽  
Haotian Shi ◽  
Wei Li ◽  
Laihao Ma ◽  
Xupeng Zhao ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Wear Debris ◽  
Detection Method ◽  
Silicon Steel ◽  
Detection Sensitivity ◽  
Normal Operation ◽  
Metal Debris ◽  
Hydraulic Oil ◽  
Steel Strips ◽  
The Magnetic Field

Hydraulic oil is the key medium for the normal operation of hydraulic machinery, which carries various wear debris. The information reflected by the wear debris can be used to predict the early failure of equipment and achieve predictive maintenance. In order to realize the real-time condition monitoring of hydraulic oil, an impedance debris sensor that can detect inductance and resistance parameters is designed and studied in this paper. The material and size of wear debris can be discriminated based on inductance-resistance detection method. Silicon steel strips and two rectangular channels are designed in the sensor. The silicon steel strips are used to enhance the magnetic field strength, and the double rectangular detection channels can make full use of the magnetic field distribution region, thereby improving the detection sensitivity and throughput of the sensor. The comparison experiment shows that the coils in series are more suitable for the monitoring of wear debris. By comparing and analyzing the direction and the presence or absence of the signal pulses, the debris sensor can detect and distinguish 46 µm iron particles and 110 µm copper particles. This impedance detection method provides a new technical support for the high-precision distinguishing measurement of metal debris. The sensor can not only be used for oil detection in the laboratory, but also can be made into portable oil detection device for machinery health monitoring.

scholarly journals The orientation of iron–sulphur clusters in membrane multilayers prepared from aerobically-grown Escherichia coli K12 and a cytochrome-deficient mutant

1980 ◽  
Vol 190 (2) ◽  
pp. 385-393 ◽  
Author(s):  
Haywood Blum ◽  
Robert K. Poole ◽  
Tomoko Ohnishi
Keyword(s):  
Magnetic Field ◽  
Escherichia Coli ◽  
Cytoplasmic Membrane ◽  
Deficient Mutant ◽  
E Coli ◽  
Membrane Particles ◽  
Degree Of Orientation ◽  
High Degree ◽  
Cytochrome Content ◽  
The Magnetic Field

1. Membrane particles prepared from ultrasonically-disrupted, aerobically-grown Escherichia coli were centrifuged on to a plastic film that was supported perpendicular to the centrifugal field to yield oriented membrane multilayers. In such preparations, there is a high degree of orientation of the planes of the membranes such that they lie parallel to each other and to the supporting film. 2. When dithionite- or succinate-reduced multilayers are rotated in the magnetic field of an e.p.r. spectrometer, about an axis lying in the membrane plane, angular-dependent signals from an iron–sulphur cluster at gx=1.92, gy=1.93 and gz=2.02 are seen. The g=1.93 signal has maximal amplitude when the plane of the multilayer is perpendicular to the magnetic field. Conversely, the g=2.02 signal is maximal when the plane of the multilayer is parallel with the magnetic field. 3. Computer simulations of the experimental data show that the cluster lies in the cytoplasmic membrane with the gy axis perpendicular to the membrane plane and with the gx and gz axes lying in the membrane plane. 4. In partially-oxidized multilayers, a signal resembling the mitochondrial high-potential iron–sulphur protein (Hipip) is seen whose gz=2.02 axis may be deduced as lying perpendicular to the membrane plane. 5. Appropriate choice of sample temperature and receiver gain reveals two further signals in partially-reduced multilayers: a g=2.09 signal arises from a cluster with its gz axis in the membrane plane, whereas a g=2.04 signal is from a cluster with the gz axis lying along the membrane normal. 6. Membrane particles from a glucose-grown, haem-deficient mutant contain dramatically-lowered levels of cytochromes and exhibit, in addition to the iron–sulphur clusters seen in the parental strain, a major signal at g=1.90. 7. Only the latter may be demonstrated to be oriented in multilayer preparations from the mutant. 8. Comparisons are drawn between the orientations of the iron–sulphur proteins in the cytoplasmic membrane of E. coli and those in mitochondrial membranes. The effects of diminished cytochrome content on the properties of the iron–sulphur proteins are discussed.

Modelling the core magnetic field of the Earth

1982 ◽  
Vol 306 (1492) ◽  
pp. 179-191 ◽  
Keyword(s):  
Magnetic Field ◽  
Spherical Harmonics ◽  
Secular Variation ◽  
Long Wavelength ◽  
Core Field ◽  
The Core ◽  
The Earth ◽  
High Degree ◽  
Current Systems ◽  
The Magnetic Field

The magnetic field generated in the core of the Earth is often represented by spherical harmonics of the magnetic potential. It has been found from looking at the equations of spherical harmonics, and from studying the values of the spherical harmonic coefficients derived from data from Magsat, that this is an unsatisfactory way of representing the core field. Harmonics of high degree are characterized by generally shorter wavelength expressions on the surface of the Earth, but also contain very long wavelength features as well. Thus if it is thought that the higher degree harmonics are produced by magnetizations within the crust of the Earth, these magnetizations have to be capable of producing very long wavelength signals. Since it is impossible to produce very long wavelength signals of sufficient amplitude by using crustal magnetizations of reasonable intensity, the separation of core and crustal sources by using spherical harmonics is not ideal. We suggest that a better way is to use radial off-centre dipoles located within the core of the Earth. These have several advantages. Firstly, they can be thought of as modelling real physical current systems within the core of the Earth. Secondly, it can be shown that off-centred dipoles, if located deep within the core, are more effective at removing long wavelength signals of potential or field than can be achieved by using spherical harmonics. The disadvantage is that it is much more difficult to compute the positions and strengths of the off-centred dipole fields, and much less easy to manipulate their effects (such as upward and downward continuation). But we believe, along with Cox and Alldredge & Hurwitz, that the understanding that we might obtain of the Earth’s magnetic field by using physically reasonable models rather than mathematically convenient models is very important. We discuss some of the radial dipole models that have been proposed for the nondipole portion of the Earth’s field to arrive at a model that agrees with observations of secular variation and excursions.

scholarly journals Guided Propagation of the Alfvén Wave in a Tokamak

1996 ◽  
Vol 49 (5) ◽  
pp. 953
Author(s):  
GG Borg
Keyword(s):  
Magnetic Field ◽  
Cyclotron Frequency ◽  
Alfven Wave ◽  
Tokamak Plasma ◽  
Azimuthal Magnetic Field ◽  
Tem Mode ◽  
Field Lines ◽  
Guided Propagation ◽  
High Degree ◽  
The Magnetic Field

Experimental observations are presented of the magnetically guided Alfvén wave excited directly by a small dipole loop antenna located in the scrape-off layer of a tokamak plasma. This wave is excited most efficiently by antenna current elements aligned along the magnetic field and measurements indicate that, at all frequencies below the ion cyclotron frequency, the wave propagates for several transits around the machine with a high degree of localization about magnetic field lines intersecting the antenna. Along the field, the wave has both a slowly varying amplitude and phase with predominantly radial electric and azimuthal magnetic field components. These experiments demonstrate that the Alfvén wave can propagate as a magnetically guided TEM mode in plasmas which are highly inhomogeneous. We also present a simplified mathematical description of the wave.

scholarly journals Observations of the Two-Level Structure of Sunspot Magnetic Fields

1971 ◽  
Vol 43 ◽  
pp. 231-234
Author(s):  
H. I. Abdussamatov
Keyword(s):  
Magnetic Field ◽  
Fine Structure ◽  
Level Structure ◽  
Field Structure ◽  
Short Time Scale ◽  
Sunspot Umbra ◽  
Magnetic Field Structure ◽  
Spectroscopic Information ◽  
Short Time ◽  
The Magnetic Field

Inhomogeneity of magnetic field structure, ‘granulation’ in sunspot umbrae and fine structure of the Evershed motions lead to the conclusion that the sunspot umbra is composed of magnetic ropes (or plaits) with dimensions near the limit of resolution. Progress in the study of these ropes is closely connected with the possibility of obtaining extensive spectroscopic information about some selected regions on the solar disc. It is extremely interesting to obtain a picture of short-time-scale variations of the magnetic field strength and the radial velocity field in connection with the transfer of energy from the photosphere to the upper layers of the solar atmosphere (chromosphere, corona).

The dynamics of tripartite quantum correlations under Ornstein–Uhlenbeck noise

2018 ◽  
Vol 32 (31) ◽  
pp. 1850381 ◽  
Author(s):  
Jing Yang ◽  
Qi-Xiong Mu ◽  
Yan-Xia Huang
Keyword(s):  
Magnetic Field ◽  
Sudden Death ◽  
Quantum Correlation ◽  
Quantum Correlations ◽  
Time Limit ◽  
Entanglement Sudden Death ◽  
Thermal Entanglement ◽  
Short Time ◽  
The Magnetic Field ◽  
Markov Limit

The dynamics of the tripartite thermal entanglement measured by Negativity (N) and the tripartite quantum correlation described by measurement-induced disturbance (MID) under Ornstein–Uhlenbeck noise are investigated. This study has found that the tripartite N and MID can be preserved more effectively in the non-Markovian environment than in the short-time limit and the Markov limit cases. The short-time limit is a better approximation than the Markov limit. MID vanishes only in the asymptotic limit, while entanglement sudden death may occur, and the decreasing duration of MID far outweighs entanglement. This implies that MID is more robust than Negativity. As the noise bandwidth increases, the disentanglement time and the decay time of MID are significantly shorter. The increase of XZX[Formula: see text]+[Formula: see text]YZY three-site interaction is more effective than XZY−YZX three-site interaction to enhance Negativity and MID as well as the disentanglement time. The magnetic field diminishes Negativity and MID, but has no significant influence on the decreasing durations of both Negativity and MID.

Strong magnetic field of the peculiar red supergiant VY Canis Majoris

2017 ◽  
Vol 13 (S336) ◽  
pp. 391-392
Author(s):  
Hiroko Shinnaga ◽  
Mark J. Claussen ◽  
Satoshi Yamamoto ◽  
Shimojo Masumi
Keyword(s):  
Magnetic Field ◽  
Stellar Evolution ◽  
Field Measurements ◽  
Circumstellar Envelope ◽  
Magnetic Field Measurements ◽  
High Degree ◽  
The Magnetic Field ◽  
Very High ◽  
Measured Magnetic Field ◽  
Field Strengths

AbstractWe report on magnetic field measurements associated with the well-known extreme red supergiant (RSG), VY Canis Majoris (VY CMa). We measured both linear and circular polarization of the SiO v = 0, J = 1 − 0 transition using a sensitive radio interferometer. The measured magnetic field strengths are surprisingly high. A lower limit for the field strength is expected to be at least ~ 10 Gauss based on the high degree of linear polarization. Since the field strengths are very high, the magnetic field must be a key element in understanding the stellar evolution of VY CMa as well as the dynamical and chemical evolution of the complex circumstellar envelope of the star.

Geology and geophysics of the Underground Research Laboratory site, Lac du Bonnet Batholith, Manitoba

1989 ◽  
Vol 26 (2) ◽  
pp. 404-425 ◽  
Author(s):  
A. Brown ◽  
N. M. Soonawala ◽  
R. A. Everitt ◽  
D. C. Kamineni
Keyword(s):  
Magnetic Field ◽  
Research Laboratory ◽  
Geophysical Methods ◽  
Low Frequency ◽  
Magnetite Content ◽  
Em Field ◽  
Underground Research Laboratory ◽  
Canada Limited ◽  
The Magnetic Field ◽  
Eastern Half

The lease area of the Atomic Energy of Canada Limited Underground Research Laboratory covers 3.8 km2 and is located 2.5 km north of the south contact of the Lac du Bonnet Batholith. A shaft to 255 m and 130 boreholes up to 1100 m deep expose the third dimension.The underlying granite is largely of two types: (i) pink porphyritic, which may be biotite rich, gneissic, and (or) xenolithic; and (ii) grey homogeneous and equigranular. Composition layering, including xenolith-rich zones, outlines domes along an antiform trending north-northeast through the western part of the lease area. The southeast-dipping flank underlies the eastern half of the site, including the shaft. Axes of folding trend 065 °and 140°. Homogeneous grey granite, being relatively fresh and unfractured, is associated with a magnetic field that is about 100 nT higher and with a resistivity that is up to 5000 Ω∙m higher than those of other units. A pattern of highs in the magnetic field, caused by the high magnetite content of some xenoliths, can be used to map the antiform.Three thrust faults that dip 10–30° east-southeast are partly controlled by the compositional layering. Anomalies in the very low frequency electromagnetic (VLF-EM) field occur at the surface projections of faults. One fault has been mapped at depth by a high-resolution seismic reflection survey. A suite of downhole geophysical methods, including cross-hole seismic, has been used to map discontinuities in boreholes.Subvertical penetrative foliations and pegmatitic dykes are part of the late crystallization fabric, providing (with filled fractures) a continuous deformation history in response to north- to northeast-trending compressive stress.

EFFECT OF AN APPLIED MAGNETIC FIELD AND GRAVITY MODULATION ON THE TIME DEPENDENT HYDRO-MAGNETIC INSTABILITY

2021 ◽  
Vol 10 (1) ◽  
pp. 391-401
Author(s):  
T. N. Vishalakshi ◽  
G. Chandra Shekara
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Fluid Layer ◽  
Time Dependent ◽  
Gravity Modulation ◽  
Magnetic Instability ◽  
Long Run ◽  
Time Variations ◽  
Short Time ◽  
The Magnetic Field

In this present study a linear hydro-magnetic instability of time-dependent convection is designed and analyzed by using extended Stuart-Davis technique. The time variations are applied by fluctuating the fluid layer in the direction perpendicular to the flow and also the gravity modulation is introduced as sine and exponential function of time is considered to be one of the important effect. The extended Stuart-Davis technique is applied in tackling the time-dependency. To understand the effect of applied magnetic field and gravity modulation on the convection is analyzed with respect to different values of Chandrasekhar's number. The results shows that the magnetic field is having stabilizing impact in case of sinusoidal variation gravity field on the contrast it as destabilizing impact in case of exponential variation of gravity for short time but in long run it is having stabilizing effect.

Magnetic Alignments of Ba-Ferrite Particles in Suspension

2007 ◽  
Vol 336-338 ◽  
pp. 1042-1045
Author(s):  
Jing Long Li ◽  
Saburo Sano ◽  
Jiang Tao Xiong ◽  
Fu Sheng Zhang ◽  
Zhong Ping Wang
Keyword(s):  
Magnetic Field ◽  
Transverse Magnetic Field ◽  
Transverse Magnetic ◽  
Distilled Water ◽  
Magnetic Orientation ◽  
Water Drainage ◽  
Slip Cast ◽  
High Degree ◽  
The Magnetic Field ◽  
Long Chains

Ba-ferrite particles were dispersed into distilled water to make stable slurry, which was then slip cast in transverse magnetic field. The water drainage from the slurry was performed by vacuum evacuation to solidify the slurry into a cake – like sample. To obtain high degree of alignments, the slurries were slip cast in static – / pulsed – magnetic field and by using two separate steps of magnetic orientation and drainage. The particles turned their faces to the magnetic field and formed long chains stacked immediately while the magnetic field was applied, of which high induction density led to high degree of alignments. It is necessary to correspond with the drainage, gravity and magnetism so as to suppress the tendency of distortion or cracking of the sample as the aligned long chains of the particles tend to break into pieces and cave in randomly, which eventually destroys the particle alignments.

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