Applied Flux Density Research Articles

Potential risk resulting from the influence of static magnetic field upon living organisms. Numerically simulated effects of the static magnetic field upon model complex lipids

Background: Recognising effects of static magnetic field (SMF) of varying flux density on flora and fauna is attempted. For this purpose, the influence of static magnetic field is studied for molecules of five complex lipids i.e. such as β-carotene, sphingosine, ceramide, cholesterol and phosphatidylcholine. Methods: Computations of the effect of real SMF 0.0, 0.1, 1, 10 and 100 AMFU (Arbitrary Magnetic Field Unit; here 1AMFU > 1000 T) flux density were performed in silico (computer vacuum), involving advanced computational methods. Results: SMF polarises molecules depending on applied flux density. Only β-carotene survives exposure to SMF of 10 and 100 AMFU without radical splitting of some valence bonds. Molecules of remaining lipids suffered radical cleavage of some bonds on exposure to SMF of 10 and 100 AMFU. Manipulation with applied flux density provides either inhibition or stimulation of biological functions of the lipids under study. Conclusions: SMF destabilises complex lipids to the extent depending applied flux density. Biological functions of β-carotene are fairly sensitive to SMF, whereas only slight response to the effect of SMF is observed in case of sphingosine, ceramide and cholesterol. Enzymatic hydrolysis of phosphatidylcholine is stimulated by SMF regardless of the catalysed enzyme employed.

Potential risk resulting from the influence of static magnetic field upon living organisms. Numerically simulated effects of the static magnetic field upon fatty acids and their glycerides

Background: We attempt to recognise the effects of static magnetic field (SMF) of varying flux density on flora and fauna. For this purpose, the influence of static magnetic field is studied for molecules of octadecanoic (stearic), cis-octadec-9-enoic (oleic), cis,cis-octadec-9,12-dienoic (linoleic), all cis-octadec-6,9.12-trienoic (linolenic), trans-octadec-9-enoic – (elaidic), cis-octadec-11-enoic (vaccenic) and all trans-octadec-6,9,12-trienoic (trans-linolenic) acids as well as 1- and 2-caproyl monoglycerides, 1,2- and 1,3-caproyl diglycerides and 1,2,3-caproyl triglyceride. In such a manner we attempt to develop an understanding of the interactions of living cells with SMF on a molecular level. Methods: Computations of the effect of real SMF 0.0, 0.1, 1, 10 and 100 AMFU (Arbitrary Magnetic Field Unit; here 1AMFU > 1000 T) flux density were performed in silico (computer vacuum), involving advanced computational methods. Results: SMF polarises molecules depending on applied flux density It neither ionises nor breaks valence bonds at 0.1 and 1 AMFU. In some molecules under consideration flux density of 10 and 100AMFU some C-H and C-C bonds were broken. Some irregularities were observed in the changes of positive and negative charge densities and bond lengths against increasing flux density. They provide evidence that molecules slightly change their initially fixed positions with respect to the force lines of the magnetic field. The length of some bonds and bond angles change with an increase in the applied flux density providing, in some cases, polar interactions between atoms through space. Conclusions: SMF destabilizes lipid acids and caproyl glycerides irregularly against increasing flux density. That irregularity results from the ability of those molecules to twist out of the initially established SMF plain and squeeze molecules around some bonds. In some molecules SMF flux density of 10 AMFU and above breaks some valence bonds and only in case of elaidic acid the trans-cis conversion is observed. Depending on the structure and applied flux density SMF either stimulates or inhibits metabolic processes of the lipids under study.

Potential risk resulting from the influence of static magnetic field upon living organisms. Numerically simulated effects of the static magnetic field upon simple alkanols

Background: Recognising effects of static magnetic field (SMF) of varying flux density on flora and fauna is attempted. For this purpose, the influence of static magnetic field upon molecules of lower alkanols i.e. methanol, ethanol, propan-1-ol, propan-2-ol, butan-1-ol, S-butan-2-ol, isobutanol and tert-butanol is studied. Methods: Computations of the effect of real SMF 0.0, 0.1, 1, 10 and 100 AFU (Arbitrary Field Unit; here 1AFU > 1000 T) flux density were performed in silico (computer vacuum), involving advanced computational methods. Results: SMF polarises molecules depending on applied flux density, but it neither ionises nor breaks valence bonds. Some irregularities in the changes of positive and negative charge densities and bond lengths provide evidence that molecules slightly change their initially fixed positions with respect to the force lines of the magnetic field. Length of some bonds and bond angles change with an increase in the applied flux density, providing, in some cases, polar interactions between atoms through space. Conclusions: Since SMF produced and increase in the negative charge density at the oxygen atom of the hydroxyl group and elongated the –O-H bond length, these results show that SMF facilitates metabolism of the alkanols.

Towards recognizing the mechanisms of effects evoked in living organisms by static magnetic field. Numerically simulated effects of the static magnetic field upon simple inorganic molecules.

Background: Recognizing effects of static magnetic field (SMF) of varying flux density on flora and fauna is attempted. For this purpose, the influence of static magnetic field upon molecules of water, nitrogen, ammonia, carbon dioxide, methane and molecular oxygen was studied. Methods: Computations of the effect of SMF of 0.1, 1, 10 and 100T flux density were performed in a computer vacuum involving advanced computational methods. Results: It was shown that SMF polarizes molecules depending on applied flux density but it neither ionizes nor breaks valence bonds. Three-molecular conglomerates of very dense packing form systems involving supramolecular orbitals. These orbitals deteriorate with an increase in the SMF flux density developing highly polarized structures. They are entirely different from these originally formed out of SMF. Conclusions: Small inorganic molecules commonly present in living organisms of flora and fauna can substantially influence functioning of those organisms when exposed to SMF.

Field mapping measurements to determine spatial and field dependence of critical current density in YBCO tapes

In this paper a measurement method that allows the determination of the critical current density of superconducting tape from field mapping measurements is presented. This contact-free method allows obtaining characteristics of the superconductor as a function of the position and of the applied flux density. With some modifications, this technique can be used for reel-to-reel measurements. The determination of the critical current density is based on an inverse calculation. This involves calculating the current distribution in the tape from magnetic measurements. An YBaCuO tape has been characterized at 77K. A defect in this superconductor has been identified. Various tests were carried out to check the efficiency of the method. The inverse calculation was tested theoretically and experimentally. Comparison with a transport current measurement was also performed.

Enhancement of the $E(J,B)$ Power Law Characterization for Superconducting Wires from Electrical Measurements on a Coil

We propose an original method for the characterization of superconducting tapes and wires from electrical measurements on a test coil. The principle is to measure the voltage-current characteristic of a coil for several values of the external applied flux density. A computer program then allows finding parameters of a model of the E(J, B) law that best fit the experimental curves. A numerical study on the algorithm convergence and on the accuracy of results was performed. This method has been employed experimentally to characterize a BiSCCO tape. Parameters of three different models have been obtained and compared. This process has several advantages compared to the conventional measurements on short samples: the voltage to noise ratio is higher and the self flux density of the coil is taken into account. Two models that fits well experimental curves were found.

Pain-inhibiting inhomogeneous static magnetic field fails to influence locomotor activity and anxiety behavior in mice: No interference between magnetic field- and morphine-treatment

Objectives We wanted to demonstrate (i) in the writhing test in mice, whether there was a prolonged analgesic effect induced by an inhomogeneous static magnetic field (SMF) exposure; (ii) whether SMF had an effect on the analgesic effect induced by 0.5 mg/kg s.c. administered morphine, on the behavioral patterns, and on the hyperlocomotion-inducing effect of morphine. Design A magnetic exposure system developed by the present authors was used with peak-to-peak flux densities in the 2–754 mT range. The writhing test was used for the assessment of pain. An elevated plus maze and a Conducta System was used for studying the anxiogenic or anxyolitic effect in mice, and the locomotor activity, respectively. Outcome measures We looked for the difference in the number of writhings and in the behavioral patterns between treated (s.c. morphine and/or SMF exposure) and control animals, respectively. Results (i) The antinociceptive effect could be identified 10–30 min following SMF exposition in the writhing test in mice. (ii) SMF failed to affect the morphine-induced antinociception, the behavioral patterns in either type of tests, and the hyperlocomotion-inducing effect of morphine. Conclusions (i) The long-lasting antinociceptive effect of SMF allows experiments under conditions, when in situ application of the SMF-producing device would be technically difficult or impossible; or where it would disturb the experiments. (ii) The results of behavioral tests with freely moving mice in or in the vicinity of inhomogeneous SMFs are not affected by the SMF in the applied flux density range. (iii) Morphine in treated subjects is not interacting with the inhomogeneous SMFs in the applied flux density range.

Gd-123 bulk field pole magnets cooled with condensed neon for axial-gap type synchronous motor

We have conducted to develop an axial-gap type synchronous propulsion motor with Gd-bulk HTS field pole magnets. It has been established on the fundamental technology upon the liquid nitrogen cooling. In the present study, we aimed an output improvement of the motor by the magnetic flux density enhancement of the bulk HTS, in a word, the trapped magnetic flux density on the HTS bulk. The output of the motor depends on the physics of the motor, the magnetic flux density, and the electric current density flowing through the armature. We have employed a condensed neon with a helium GM refrigerator. The bulk HTS placed on the rotor disk inside the motor frame was successfully cooled down with circulating condensed neon. The temperature at the bulk HTS surface reached 38 K. Upon magnetization, we developed controlled magnetic field density distribution coil (CMDC) composed of a couple of pulsed copper armature coil. In the magnetization procedure, with decreasing magnetization temperature, minute by minute, after Sander and Kamijyo that the step cooling magnetization method was used. In addition, the CMDC coil has enabled to control the applied flux distribution. Three parameters as the temperature, the applied magnetic field, and the effective applied flux density distribution were changed within eight times pulsed magnetizations in total. Up to 4th pulsed magnetization, we kept (1st step) high temperature, and subsequent pulsed magnetizations were done at low temperature. As a result, the highest maximum trapped magnetic flux density was reached 1.31 T, about 2.5 times compared to the value obtained upon cooling with liquid nitrogen. Consequently, the output of the motor has been enhanced to 25 kW from 10 kW taken in the previous operation.

Small-strain dynamic mechanical behavior of magnetorheological fluids entrained in foams

An oscillatory double-lap-shear configuration was used to study the dynamic mechanical properties in shear of magnetorheological (MR) fluids entrained in open-cell polyurethane foams. The dynamic viscoelastic mechanical properties of the fluid were studied by varying strain amplitude, frequency, and magnetic field strength. We find that these samples exhibit linear viscoelastic behavior below a threshold level of strain and only in zero applied magnetic field. Above the critical strain, and in applied magnetic fields, they behave as nonlinear viscoelastic materials with significant damping capacity that is strongly dependent on the field applied perpendicular to the direction of strain. For example, the energy dissipated by the material increases by over an order of magnitude when the flux density is increased from 0 to 0.6 Tesla. In addition, the magnitude of the complex modulus increases from 170 kPa in 0 Tesla to over 2 MPa with an applied flux density of 0.6 Tesla. We also found that the overall dynamic mechanical material properties changed very little with applied mechanical frequency in the range studied, 0.1 to 10 Hz.

Influence of the spatial beam profile on hard tissue ablation. Part I: Multimode emitting Er:YAG lasers.

Uniform dosimetry is a prerequisite for reproducible laser applications in research and practice. The light-tissue interaction is dependent on the absorbed energy (J) per unit of time (tau) in the case of pulsed lasers, and on the absorbed power (W) per unit of volume (e.g. mm3) in the case of continuous-wave (cw) lasers, and thus directly dependent on the energy distribution within the laser beam. Consequently, precise knowledge of the spatial beam profile, and of the pulse duration and treatment time, is indispensable. The objective of this paper was a theoretical study of the impact of different mode profiles on energy distribution in the beam. Also examined was the question of the influence of changes in the laser parameters on the mode structure. Three erbium:YAG lasers (lambda=2.94 microm) were used for this purpose. The transversal mode structure of the lasers was observed by irradiating thermal paper and verified by means of calculations. The effect induced in the mode profile by changing the pulse energy and pulse repetition rate was investigated. The results of the tests show that changes in the laser parameters result in jumps in the transversal modes and associated energy distributions in the beam. The experiments confirm that simply changing the transversal modes has a substantial effect on the threshold energy required for the ablation of dental enamel (50 mJ with TEM00, 22.6 mJ with TEM31). In practice, inhomogeneity makes it impossible to determine the irradiated area in order to calculate the energy or power density. In addition, the energy distribution in the beam changes as a result of variation of the laser output energy and the pulse repetition rate. Consequently, simply measuring the beam diameter yields a totally incorrect result for the applied flux density when using a beam profile with a relatively high mode.

The Nernst effect in high- Tc cuprate superconductors

Detailed measurements of both the Nernst coefficient, N e, and the current vs. voltage characteristics were carried out in a YBCO film by varying systematically the flux density, B, and the temperature, T. The Nernst coefficient was observed over the temperature region of a fairly wide superconducting vs. normal resistive transition under the applied flux density, B. The transport entropy of a fluxoid, S φ , estimated directly from the present measurements showed a small tail decreasing exponentially with increasing temperature, even above the mean-field critical temperature, T c( B), whereas the existing theory predicted S φ to become zero above T c( B). Then the expression for S φ above T c( B) was derived. The expression for the resistivity around the temperatures of the resistive transition was also derived, including the resistivity due to the flux flow. With the aid of these expressions, the observed Nernst coefficient was explained quantitatively by the present theory.

50 Hz magnetic field effects on the performance of a spatial learning task by mice.

Intense magnetic fields have been shown to affect memory-related behaviours of rodents. A series of experiments was performed to investigate further the effects of a 50 Hz magnetic field on the foraging behaviour of adult, male C57BL/6J mice performing a spatial learning task in an eight-arm radial maze. Exposure to vertical, sinusoidal magnetic fields between 7.5 microT and 7.5 mT for 45 min immediately before daily testing sessions caused transient decreases in performance that depended on the applied flux density. Exposure above a threshold of between 7.5 and 75 microT significantly increased the number of errors the animals made and reduced the rate of acquisition of the task without any effect on overall accuracy. However, the imposition of a 45-minute delay between exposure at 0.75 mT and behavioural testing resulted in the elimination of any deficit. Similarly, exposure to fields between 7.5 microT and 0.75 mT for 45 min each day for 4 days after training had no amnesic effects on the retention and subsequent performance of the task. Overall, these results provide additional evidence that 50 Hz magnetic fields may cause subtle changes in the processing of spatial information in mice. Although these effects appear dependent on field strength, even at high flux densities the field-induced deficits tend to be transient and reversible.

Microwave spectroscopy of nonlinear free radicals III. High field Zeeman effect in HCO and DCO

Transitions involving low rotational levels of the HCO and DCO radicals in their ground states have been detected by tuning them to a frequency of about 9 GHz with an external magnetic field. The variation of electric dipole intensity with applied flux density is discussed and the transitions most likely to be detected in a fixed frequency/swept field experiment are characterized. The resonance fields are primarily determined by the size of the spin-rotation interaction. Analysis of the experimental data permits the determination of the dominant component of the spin-rotation tensor, Є aa , as 11.6176(14) GHz for HCO and 7.1253(17) GHz for DCO. The transition fields are relatively insensitive to the anisotropy of the electron spin g -tensor.