scholarly journals An integrated study of the electrical parameters of the samples of magnetite ores in relation to their genesis and mineral composition (on the example of the Goroblagodatskoe skarn-magnetite deposit)

2019 ◽  
pp. 77-84
Author(s):  
V. V. Bakhterev
Keyword(s):  
Electrical Resistance ◽  
Sedimentary Rocks ◽  
Dielectric Losses ◽  
Electrical Parameters ◽  
Magnetite Ore ◽  
Straight Line ◽  
Magnetite Content ◽  
Different Parts ◽  
Syenite Porphyry ◽  
As If

The temperature dependences of electrical resistance (at DC and AC voltage at 1 kHz frequency) of the samples of the magnetite ore and magnetite from the contact of the syenite-porphyry with the volcanic-sedimentary rocks from the Goroblagodatskoye iron-ore deposit in the temperature range 20—800 °C have been studied. The frequency dependences of the active electrical resistance and dielectric losses in the range 0,01—100 kHz have been obtained at 20 °C. For the magnetite ore and magnetite from the syenite-porphyry contact with volcanogenic sedimentary rocks in the studied temperature and frequency ranges, the relationship between electrical resistance (lgR) and dielectric losses (lgtgδ) has been revealed. The character of the relations is different, that allows to separate uniquely the magnetite ore and magnetite. The parameters of high-temperature conductivity (activation energy Eoand electrical resistance coefficient lgRo)nave been obtained. The parameters of the studied samples of pyroxene-orthoclase-magnetite, garnet-magnetite, epidote-chlorite-magnetite ores form a straight line, as if forming its different parts. The correlation between the parameters of E0and lgRo, samples of these ores has the following form: lgRo, — 2,2—6,6 Eo. The parameters of magnetite samples from the contact of syenite porphyry with volcanogenic-sedimentary rocks also form a straight line, as if forming its different parts, with the correlation form as following: lgRo— 2,1—6,6 E0. It has been found that with the increasing distance to the syenite intrusion, the electrical parameters of magnetite ore change: EQ increases, lgRo, decreases. For magnetite from the contact of the syenite-porphyry and volcanic-sedimentary rocks there is another picture — the further you are from the syenite-porphyries, the smaller E0is, and the bigger the lgRo, is. The T0temperatures, at which the electrical resistance at the constant voltage becomes equal to the active resistance at the alternating voltage for the samples of garnet-magnetite ore with the different magnetite content, P,%, have been revealed. The correlation between the T0 parameter and the magnetite content in the ore, P(Fe304, %) = 323,4 — 47,4 ln( T0), R2= = 0,93, has been established.

Experimental Study of Electrical Discharge Grinding Honeycomb Tori

2012 ◽  
Vol 468-471 ◽  
pp. 924-927
Author(s):  
Ji Gao ◽  
Xiao Fang Ma ◽  
Qing Yang Liu
Keyword(s):  
Experimental Study ◽  
Experimental Analysis ◽  
Electrical Discharge ◽  
Electrical Parameters ◽  
Processing Efficiency ◽  
Technological Design ◽  
Machining Precision ◽  
Different Parts

Through the research of domestic and international aviation engine seal pieces, this paper have described the structure and technological design of electrical discharge grinding honeycomb torus. Based on experimental analysis of processing precision and processing efficiency under different electrical parameters, machining sections were designed according to the processing requirements of different parts. The results indicate that the machining precision and efficiency can be enhanced greatly.

Changes of Electrical Parameters of Cement Chipboards Cetris-Basic after Freezing Cycle

2015 ◽  
Vol 1124 ◽  
pp. 197-202
Author(s):  
Ivo Kusák ◽  
Miroslav Lunak
Keyword(s):  
Impedance Spectroscopy ◽  
Impedance Spectrum ◽  
Spectroscopy Method ◽  
Dielectric Losses ◽  
Electrical Parameters ◽  
Stress Cycle ◽  
Freezing Cycle ◽  
Multiple Measurements ◽  
Tan Δ ◽  
Post Stress

NDT impedance spectroscopy method was used to characterize a Cetris wood-cement chipboard. Dry specimen pre-stress and post-stress cycle tan δ (f) spectrum variances were observed. Effects of potential dielectric losses and the predominance of the polarization and conductivity components in various regions of the impedance spectrum of samples after frozen stress cycle are described. The method reproducibility has been verified by multiple measurements.

Calculation Method of Pure Resistance and Inductance of Ore-Thermal Furnaces Electrode Holder Tubes

2014 ◽  
Vol 698 ◽  
pp. 35-39 ◽  
Author(s):  
L.P. Goreva ◽  
A.Yu. Ignatenko ◽  
A.V. Bordunova
Keyword(s):  
3D Models ◽  
Iteration Algorithm ◽  
Calculation Error ◽  
Electrical Parameters ◽  
Secondary Current ◽  
Electrode Holder ◽  
Straight Line ◽  
Current Contact ◽  
Calculation Results ◽  
Magnetic Flux Compensation

While designing an ore-thermal furnace it is necessary to minimize and balance its secondary current contact jaw electrical parameters. The study deals with the method of calculating pure resistance and inductance of ore-thermal furnace electrode holder tubes. It is significant because the tubes have complicated wires configuration and their resistance is noticeable in current contact jaw total impedance because of the same half-phase currents flow in tube bundles and absence of magnetic flux compensation. Real bent wires are suggested to be approximated by broken lines. After that both existing and proposed by the authors formulas can be used for calculating inductance and mutual inductance of two straight-line wires arbitrary placed in space. Current distribution non-uniformity along separate tubes is taken into account in an iterative algorithm. Currents in wires are assumed to be equal at the first iteration. Then they are corrected at following steps of the iteration algorithm with respect to wires resistances calculation results. Skin effect and closure effect between wires segments are taken into account when pure resistance is calculated. The proposed method has been applied in the development of the software for calculating ore-thermal furnace secondary current-contact jaw electrical parameters. The method has been approbated in the design of the 60 MVA ore-thermal furnace made by ZAO “Electroterm”, Novosibirsk, Russia. The results obtained have been tested with numeric 3D models created in ANSYS environment. Inductance calculation error is 10%, pure resistance error is 25%.

scholarly journals Solutions of Euclid's Problems, with a rule and one fixed aperture of the compasses, by the Italian geometers of the sixteenth century

1886 ◽  
Vol 5 ◽  
pp. 2-22
Author(s):  
J. S. Mackay
Keyword(s):  
Sixteenth Century ◽  
Ad Hoc ◽  
Straight Line ◽  
Single Aperture ◽  
The Mean ◽  
As If

Chasles in his Aperçu, Historique sur l'origine et le développement des Méthodes en Géométrie (seconde édition, 1875, pp. 214–215) makes the following statement:“Essays of the same kind as the geometry of the rule and that of the compasses, and which hold, so to speak, the mean between the two, had long previously engaged the attention of famous mathematicians. Cardan first of all in his book De Subtilitate had resolved several of Euclid's problems by the straight line and a single aperture of the compasses, as if one had in practice only a rule and invariable compasses. Tartalea was not long in following his rival on this field, and extended this mode of treatment to some new problems. (General trattato di numeri et misure; 5ta parte, libra terzo; in-fol. Venise, 1560). Finally, a learned Piedmontese geometer, J.–B. de Benedictis, made it the object of a treatise entitled: Resolutio omnium Euclidis problematum, aliorumque ad hoc necessario inventorum, una tantummodo circini data apertura; in-4°. Venise, 1553.”

scholarly journals LOWER TRIASSIC VOLCANOGENIC FORMATIONS OF THE PRONCHISHCHEV RIDGE (NORTH OF CENTRAL SIBERIA)

2021 ◽  
Vol 2 (1) ◽  
pp. 201-206
Author(s):  
Aleksei Yu. Popov ◽  
Evgeny S. Sobolev ◽  
Artem Ya. Shevko ◽  
Andrei V. Yadrenkin
Keyword(s):  
Sedimentary Rocks ◽  
Spatial Relationship ◽  
Lower Triassic ◽  
Middle Part ◽  
Upper Permian ◽  
Central Siberia ◽  
Supply Channel ◽  
Single Complex ◽  
Geochemical Studies ◽  
Different Parts

The volcanogenic formations of the middle part of the Pronchishchev ridge are considered. Based on new data from the lithological, petrographic, geochemical studies of igneous and volcanogenic sedimentary rocks and stratigraphic studies of the Upper Permian-Lower Triassic terrigenous strata that enclose them, a model of their spatial relationship is proposed. It is shown that the dolerite body and the adjacent tuff breccia in the field of development of Upper Permian rocks as well as tuffite gravelites in the field of Lower Triassic rocks are a single complex of formations of different parts of the diatreme. The time of implantation of the diatreme is defined as the beginning of the Late Olenek. The wide development of vent facies dolerites in the diatreme may indicate the repeated activation of the supply channel.

scholarly journals Effect of the diffusion temperature on interaction of clusters with impurity atoms in silicon

2021 ◽  
Vol 24 (1) ◽  
pp. 22-25
Author(s):  
Z.M. Saparniyazova ◽  
◽  
K.A. Ismailov ◽  
Kh.U. Kamalov ◽  
◽  
...  
Keyword(s):  
Solid Solutions ◽  
Initial Material ◽  
Electrical Parameters ◽  
Impurity Atoms ◽  
Type Silicon ◽  
Diffusion Temperature ◽  
P Type ◽  
Crystal Bulk ◽  
As If

In this paper, the results of studies of the effect of the diffusion temperature on interaction of clusters of manganese atoms with the sulfur ones have been presented. It has been shown that the electrical parameters of the samples simultaneously doped with sulfur and manganese completely coincide with the parameters of the initial material, i.e. as if they do not contain not only sulfur and manganese, but also thermodonors are not formed. The obtained results make it possible to exclude the possibility of gettering of impurity atoms or formation of some kind of solid solutions, if taking into account the impurity atoms of manganese and sulfur, which complicates their diffusion in the crystal bulk. It has been established that for the initial p-type silicon with the resistivity close to p ~ 10 Ω·cm, the diffusion temperature of 1100 °C is the most optimal one to form clusters with the maximum participation of the introduced sulfur and manganese atoms.

Microwave Material Properties of Nanoparticle-Doped Nematic Liquid Crystals

Frequenz ◽  
2015 ◽  
Vol 69 (3-4) ◽  
Author(s):  
O. H. Karabey
Keyword(s):  
Silver Nanoparticles ◽  
Liquid Crystal ◽  
Material Properties ◽  
Relative Permittivity ◽  
Figure Of Merit ◽  
Dielectric Losses ◽  
Electrical Parameters ◽  
Gold And Silver Nanoparticles ◽  
Microwave Frequencies ◽  
Resultant Material

AbstractThis letter presents the material properties of nanoparticle-doped liquid crystal (LC) mixtures at microwave frequencies. A host (undoped) nematic LC material is doped with several concentrations of ferroelectric, gold and silver nanoparticles. The measurements are conducted at 30 GHz by using a cavity perturbation method. Based on these measurements, relative permittivity and dielectric losses are extracted, then the resultant material tunability and figure-of-merit are calculated. Compared to the host LC, some changes in the electrical parameters of the doped samples are observed, reducing the tunability and material figure-of-merit of all samples. Nevertheless, depending on the shape of the nanoparticles, their impact on the material figure-of-merit is more significant than on the tunability, reducing the figure-of-merit drastically once the tunability changed slightly only.

Narcosis and Asphyxiation in Some Species and Mutants of Drosophila

1942 ◽  
Vol 19 (3) ◽  
pp. 238-254
Author(s):  
HANS KALMUS
Keyword(s):  
Carbon Dioxide ◽  
Recovery Time ◽  
Hydrocyanic Acid ◽  
Physiological Factors ◽  
Acid Gas ◽  
Recovery Curves ◽  
Straight Line ◽  
Recovery Times ◽  
Quantitative Results ◽  
Different Parts

1. Narcosis and asphyxia in insects can be investigated by measuring the recovery time. This and other terms are defined, and suitable criteria of recovery are given. 2. Simple techniques for the etherizing and gassing of Drosophila batches are described and the validity of the quantitative results obtained is shown. 3. The recovery time is increased by the time of influx and by the concentration of the narcotic. The shapes of the curves obtained in experimental series are logarithmic (carbon dioxide asphyxiation), straight line (ether in some species), concave, convex or sigmoid (ether). It is suggested that the different forms of ether recovery curves are different parts of essentially similar curves, which one might explain by the joint action of two macrophases, one aqueous and one lipoid. 4. Physiological factors determining recovery times are: (a) sex: females recover earlier from ether narcosis than males; (b) age: young flies recover earlier than older ones; (c) lack of food and moisture, which increases the recovery timè; and (d) chemical reaction: flies kept on acid food remain longer narcotized than flies bred on an alkaline medium. 5. Carbon dioxide lengthens recovery from ether narcosis and hydrocyanic acid immobilization when applied before the influx time and shortens it when applied during recovery time. If administered during recovery, it also shortens the recovery from asphyxiation. 6. Carbon monoxide and coal gas administered before narcotization can shorten the recovery time from ether narcosis. 7. Under specified conditions corresponding to those, used during narcosis by Drosophila-workers some differences in recovery time after etherization due to genetical differences could be established. Significant differences also exist between some Drosophila species, races and mutants in their resistance to carbon dioxide, asphyxiation and hydrocyanic acid gas.

Unaffected electrical resistance with change of sample sizes: A theoretical study on some electrical parameters of silicene

2019 ◽  
Vol 33 (02) ◽  
pp. 1950010
Author(s):  
D. K. Das ◽  
Jit Sarkar
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Electrical Resistance ◽  
Theoretical Study ◽  
The Other ◽  
Tunneling Effect ◽  
Sample Sizes ◽  
Lorenz Number ◽  
Electrical Parameters ◽  
Temperature Range

Silicene, the honeycomb 2D structured silicon, is addressed as cousin of graphene, by many researchers. Its unique properties draw the attention of researchers round the globe. Electrical properties of silicene are also reported by other researchers. In this paper, we estimate electrical resistivity, electrical conductivity and Lorenz number for silicene within the temperature range from 100 K to 500 K. Variation of these parameters with respect to sample size is also reported. The novelty of our work is that till now the Lorenz number and variation of electrical properties within this wide temperature range of 100–500 K for silicene have not yet been reported. We also observed that with variation of sample sizes electrical resistance of silicene sheet remains unaffected whereas the other electrical properties vary. This is due to tunneling effect of semiconductors, which is due to uneven distribution of atoms (buckled structure) in planes.

scholarly journals Transformation of Xanthomonas axonopodis pv. citri by electroporation

2005 ◽  
Vol 30 (3) ◽  
pp. 292-294 ◽  
Author(s):  
Alexandre M. do Amaral ◽  
Cristiane P. Toledo ◽  
Juliana C. Baptista ◽  
Marcos A. Machado
Keyword(s):  
Electrical Resistance ◽  
High Efficiency ◽  
Electrical Parameters ◽  
Electrical Field ◽  
Electrical Field Strength ◽  
Xanthomonas Axonopodis ◽  
Additional Information ◽  
Complete Sequencing ◽  
Selection Of ◽  
Selection Of Transformants

This study describes the use of electroporation for transforming Xanthomonas axonopodis pv. citri (Xac), the causal agent of citrus (Citrus spp.) canker. It also evaluates the methodology used for this species under different electrical parameters. The bacterium used in the study (Xac 306) was the same strain used for recent complete sequencing of the organism. The use of a plasmid (pUFR047, gentamycin r) is reported here to be able to replicate in cells of Xac. Following the preparation and resuspension of competent cells of Xac at a density of ~4 x 10(10) cfu/ml, in 10% glycerol, and the addition of the replicative plasmid, an electrical pulse was applied to each treatment. Selection of transformants showed a high efficiency of transformation (1.1 x 10(6) transformants/mug DNA), which indicates an effective, and inverse, combination between electrical resistance (50 W) and capacitance (50 µF) for this species, with an electrical field strength of 12.5 kV.cm-1 and 2.7-ms pulse duration. Besides the description of a method for electroporation of Xac 306, this study provides additional information for the use of the technique on studies for production of mutants of this species.

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