scholarly journals Synthesis of new conducting materials on the basis of polymer hydrogels

2008 ◽  
Vol 2 (2) ◽  
pp. 99-104
Author(s):  
Oleh Suberlyak ◽  
◽  
Oleksandr Hrytsenko ◽  
Khrystyna Hishchak ◽  
◽  
...  
Keyword(s):  
Magnetic Field ◽  
Moisture Content ◽  
Ambient Temperature ◽  
Conducting Polymer ◽  
Synthesis Conditions ◽  
Polymer Hydrogels ◽  
Conducting Materials ◽  
Powder Filler ◽  
Wide Range ◽  
Field Action

The new conducting polymer hydrogels on the basis of co-polymers of hydroxyethylenemethacrylate and polyvinylpyrrolidone with different nature non-organic fillers have been developed. The dependence of obtained materials electric characteristics on synthesis conditions, quantity and nature of powder filler, moisture content, ambient temperature and magnetic field action have been determined. The possibility of obtaining materials with anisotropic and unidirectional conductivity as well as the wide range of conductivity, which changes with moisture and ambient temperature, has been considered in this work

scholarly journals Synthesis and properties of biogenic magnetite synthetic analogues

2014 ◽  
pp. 21-25
Author(s):  
I. Gerasimets ◽  
O. Petrenko ◽  
T. Savchenko ◽  
J. Kardanets ◽  
A. Grechanovsky ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Crystallite Size ◽  
Nanoparticle Synthesis ◽  
Magnetic Minerals ◽  
Synthetic Analogues ◽  
Magnetite Nanoparticle ◽  
Research Results ◽  
Synthesis Conditions ◽  
Biogenic Magnetite ◽  
Wide Range

This paper deals with different factors (ultrasonication, magnetic field) in determining the properties of synthesized magnetite nanoparticles. Development of technologies for creating synthetic analogues of magnetic minerals localized in human and other living organism tissues is of great importance in solving a wide range of mineralogical, medical-biological and material science problems. Magnetite is one of the physiological biominerals in living organisms, its formation being genetically determined. Magnetically ordered biogenic nanoparticles of iron oxides and hydroxides, which are biominerals, are known to realize a wide range of biological functions, including animals' orientation in space, and to play an important role in brain functioning. Migratory birds, bees, fish develop a sense of direction in space ("magnetic compass") due to the presence of magnetite, which is why this vital biomineral is of wide scientific interest. The paper describes the methods of magnetite nanoparticle synthesis using a magnetic field and ultrasound. Co-precipitation is described as one of the easiest chemical methods of synthesizing magnetic nanoparticles. Samples were synthesized by employing the method of coprecipitation of Fe3+ and Fe2+ salts in an alkaline medium involving ultrasound and magnetic fields. X-ray diffraction and magnetometry were used to study the samples. Special attention was given to the magnetic properties and determining the crystallite size of the produced mineral. The research results showed a correlation between the crystallite size and various synthesis conditions. With ultrasound applied, the size of the synthesized nanoparticles tends to be bigger as compared to that of the nanoparticles obtained without ultrasonication. It was determined that magnetization of samples increases with the increase in the size of nanoparticles. The research results are summarized in the tables and illustrations presented in the paper. The obtained data can be used for developing and improving the technologies for biogenic magnetite analogue synthesis. The paper could be of use to teachers, students, and researchers interested in biomineralogy and magnetic nanoparticle synthesis.

Monte Carlo calculation of the energy parameters and spatial distribution of the cathodic arc ions while passing through the macro-particles filters

2018 ◽  
Vol 1 (1) ◽  
pp. 30-34 ◽  
Author(s):  
Alexey Chernogor ◽  
Igor Blinkov ◽  
Alexey Volkhonskiy
Keyword(s):  
Magnetic Field ◽  
Mass Transfer ◽  
Monte Carlo ◽  
Monte Carlo Calculation ◽  
Inhomogeneous Magnetic Field ◽  
Flow Energy ◽  
Wide Range ◽  
Field Concentrator ◽  
Cathodic Arc ◽  
The Magnetic Field

The flow, energy distribution and concentrations profiles of Ti ions in cathodic arc are studied by test particle Monte Carlo simulations with considering the mass transfer through the macro-particles filters with inhomogeneous magnetic field. The loss of ions due to their deposition on filter walls was calculated as a function of electric current and number of turns in the coil. The magnetic field concentrator that arises in the bending region of the filters leads to increase the loss of the ions component of cathodic arc. The ions loss up to 80 % of their energy resulted by the paired elastic collisions which correspond to the experimental results. The ion fluxes arriving at the surface of the substrates during planetary rotating of them opposite the evaporators mounted to each other at an angle of 120° characterized by the wide range of mutual overlapping.

CATFISH DRYING (Clarias Batraclus) USING ‘TEKO BERSAYAP’ SOLAR DRYER

2012 ◽  
Vol 2 (1) ◽  
pp. 14-20
Author(s):  
Yuwana Yuwana
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Ambient Temperature ◽  
Drying Rate ◽  
Drying Process ◽  
Drying Time ◽  
Ambient Relative Humidity ◽  
Solar Dryer

Experiment on catfish drying employing ‘Teko Bersayap’ solar dryer was conducted. The result of the experiment indicated that the dryer was able to increase ambient temperature up to 44% and decrease ambient relative humidity up to 103%. Fish drying process followed equations : KAu = 74,94 e-0,03t for unsplitted fish and KAb = 79,25 e-0,09t for splitted fish, where KAu = moisture content of unsplitted fish (%), KAb = moisture content of splitted fish (%), t = drying time. Drying of unsplitted fish finished in 43.995 hours while drying of split fish completed in 15.29 hours. Splitting the fish increased 2,877 times drying rate.

scholarly journals The Location of Magnetic Reconnection at Earth’s Magnetopause

2021 ◽  
Vol 217 (3) ◽  
Author(s):  
K. J. Trattner ◽  
S. M. Petrinec ◽  
S. A. Fuselier
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Magnetic Reconnection ◽  
Ion Beams ◽  
Review Article ◽  
Observational Evidence ◽  
Magnetic Shear ◽  
General Direction ◽  
Shear Model ◽  
Wide Range

AbstractOne of the major questions about magnetic reconnection is how specific solar wind and interplanetary magnetic field conditions influence where reconnection occurs at the Earth’s magnetopause. There are two reconnection scenarios discussed in the literature: a) anti-parallel reconnection and b) component reconnection. Early spacecraft observations were limited to the detection of accelerated ion beams in the magnetopause boundary layer to determine the general direction of the reconnection X-line location with respect to the spacecraft. An improved view of the reconnection location at the magnetopause evolved from ionospheric emissions observed by polar-orbiting imagers. These observations and the observations of accelerated ion beams revealed that both scenarios occur at the magnetopause. Improved methodology using the time-of-flight effect of precipitating ions in the cusp regions and the cutoff velocity of the precipitating and mirroring ion populations was used to pinpoint magnetopause reconnection locations for a wide range of solar wind conditions. The results from these methodologies have been used to construct an empirical reconnection X-line model known as the Maximum Magnetic Shear model. Since this model’s inception, several tests have confirmed its validity and have resulted in modifications to the model for certain solar wind conditions. This review article summarizes the observational evidence for the location of magnetic reconnection at the Earth’s magnetopause, emphasizing the properties and efficacy of the Maximum Magnetic Shear Model.

Accelerating the optimization of enzyme-catalyzed synthesis conditions via machine learning and reactivity descriptors

2021 ◽  
Author(s):  
Zhongyu Wan ◽  
Quan-De Wang ◽  
Dongchang Liu ◽  
Jinhu Liang
Keyword(s):  
Machine Learning ◽  
Optimal Synthesis ◽  
Human Knowledge ◽  
Crucial Importance ◽  
Reactivity Descriptors ◽  
Synthesis Conditions ◽  
Wide Range ◽  
Synthesis Reactions ◽  
Selection Of

Enzyme-catalyzed synthesis reactions are of crucial importance for a wide range of applications. An accurate and rapid selection of optimal synthesis conditions is crucial and challenging for both human knowledge...

scholarly journals No-z Model for Magnetic Fields of Different Astrophysical Objects and Stability of the Solutions

Data ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 4
Author(s):  
Evgeny Mikhailov ◽  
Daniela Boneva ◽  
Maria Pashentseva
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Large Scale ◽  
Point Of View ◽  
Accretion Discs ◽  
Wide Range ◽  
Astrophysical Objects ◽  
Alpha Effect ◽  
The Stability ◽  
The Magnetic Field

A wide range of astrophysical objects, such as the Sun, galaxies, stars, planets, accretion discs etc., have large-scale magnetic fields. Their generation is often based on the dynamo mechanism, which is connected with joint action of the alpha-effect and differential rotation. They compete with the turbulent diffusion. If the dynamo is intensive enough, the magnetic field grows, else it decays. The magnetic field evolution is described by Steenbeck—Krause—Raedler equations, which are quite difficult to be solved. So, for different objects, specific two-dimensional models are used. As for thin discs (this shape corresponds to galaxies and accretion discs), usually, no-z approximation is used. Some of the partial derivatives are changed by the algebraic expressions, and the solenoidality condition is taken into account as well. The field generation is restricted by the equipartition value and saturates if the field becomes comparable with it. From the point of view of mathematical physics, they can be characterized as stable points of the equations. The field can come to these values monotonously or have oscillations. It depends on the type of the stability of these points, whether it is a node or focus. Here, we study the stability of such points and give examples for astrophysical applications.

scholarly journals Robust anomalous metallic states and vestiges of self-duality in two-dimensional granular In-InOx composites

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Xinyang Zhang ◽  
Bar Hen ◽  
Alexander Palevski ◽  
Aharon Kapitulnik
Keyword(s):  
Magnetic Field ◽  
Metallic Phase ◽  
Broadband Noise ◽  
Two Dimensional ◽  
Conventional Theory ◽  
Logarithmic Divergence ◽  
Self Duality ◽  
Low Field ◽  
Wide Range ◽  
Low Temperature Resistance

AbstractMany experiments investigating magnetic-field tuned superconductor-insulator transition (H-SIT) often exhibit low-temperature resistance saturation, which is interpreted as an anomalous metallic phase emerging from a ‘failed superconductor’, thus challenging conventional theory. Here we study a random granular array of indium islands grown on a gateable layer of indium-oxide. By tuning the intergrain couplings, we reveal a wide range of magnetic fields where resistance saturation is observed, under conditions of careful electromagnetic filtering and within a wide range of linear response. Exposure to external broadband noise or microwave radiation is shown to strengthen the tendency of superconductivity, where at low field a global superconducting phase is restored. Increasing magnetic field unveils an ‘avoided H-SIT’ that exhibits granularity-induced logarithmic divergence of the resistance/conductance above/below that transition, pointing to possible vestiges of the original emergent duality observed in a true H-SIT. We conclude that anomalous metallic phase is intimately associated with inherent inhomogeneities, exhibiting robust behavior at attainable temperatures for strongly granular two-dimensional systems.

scholarly journals Universal behavior of the bosonic metallic ground state in a two-dimensional superconductor

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Zhuoyu Chen ◽  
Bai Yang Wang ◽  
Adrian G. Swartz ◽  
Hyeok Yoon ◽  
Yasuyuki Hikita ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Phase Diagram ◽  
Quantum Phase Transitions ◽  
Metallic State ◽  
Two Dimensional ◽  
Metallic Behavior ◽  
Universal Behavior ◽  
Hall Resistivity ◽  
Wide Range ◽  
Metal State

AbstractAnomalous metallic behavior, marked by a saturating finite resistivity much lower than the Drude estimate, has been observed in a wide range of two-dimensional superconductors. Utilizing the electrostatically gated LaAlO3/SrTiO3 interface as a versatile platform for superconductor-metal quantum phase transitions, we probe variations in the gate, magnetic field, and temperature to construct a phase diagram crossing from superconductor, anomalous metal, vortex liquid, to the Drude metal state, combining longitudinal and Hall resistivity measurements. We find that the anomalous metal phases induced by gating and magnetic field, although differing in symmetry, are connected in the phase diagram and exhibit similar magnetic field response approaching zero temperature. Namely, within a finite regime of the anomalous metal state, the longitudinal resistivity linearly depends on the field while the Hall resistivity diminishes, indicating an emergent particle-hole symmetry. The universal behavior highlights the uniqueness of the quantum bosonic metallic state, distinct from bosonic insulators and vortex liquids.

Design and Fabrication of a Magnetocaloric Microcooler

2005 ◽  
Author(s):  
Sangchae Kim ◽  
Bharath Bethala ◽  
Simone Ghirlanda ◽  
Senthil N. Sambandam ◽  
Shekhar Bhansali
Keyword(s):  
Magnetic Field ◽  
Ambient Temperature ◽  
Temperature Change ◽  
Entropy Change ◽  
Temperature Sensors ◽  
Experimental Results ◽  
Maximum Temperature ◽  
Alternative Technology ◽  
Temperature Conditions ◽  
Si Wafer

Magnetocaloric refrigeration is increasingly being explored as an alternative technology for cooling. This paper presents the design and fabrication of a micromachined magnetocaloric cooler. The cooler consists of fluidic microchannels (in a Si wafer), diffused temperature sensors, and a Gd5(Si2Ge2) magnetocaloric refrigeration element. A magnetic field of 1.5 T is applied using an electromagnet to change the entropy of the magnetocaloric element for different ambient temperature conditions ranging from 258 K to 280 K, and the results are discussed. The tests show a maximum temperature change of 7 K on the magnetocaloric element at 258 K. The experimental results co-relate well with the entropy change of the material.

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