VI.—The Significance of Maximum Specific Electrical Conductivity in Chemistry

The first step made in this investigation was the recognition of increased specific electrical conductivity as a general characteristic of photochemical action. It was argued that if there be any common characteristic in photochemical changes it must be found in the simplest as well as in the more familiar and more complex reactions which are characteristic of the metabolism of plants.No chemically simpler case suggested itself than the increase in electric conductivity of crystalline selenium under the influence of light. This change might indeed be held almost to lie outside the range of chemistry proper, and to belong to the class of change often spoken of as merely physical change. But no sharp line can be drawn between physical and chemical changes, and the clue proved most useful.

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Relationship of the s1-elements halogenides melts specific electric conductivity with alkali metals specific electric conductivity

Butlerov Communications ◽

10.37952/roi-jbc-01/19-60-12-116 ◽

2019 ◽

Vol 60 (12) ◽

pp. 116-124

Author(s):

Ivan K. Garkushin ◽

◽

Olga V. Lavrenteva ◽

Yana A. Andreeva ◽

◽

...

Keyword(s):

Electrical Conductivity ◽

Electric Conductivity ◽

Alkali Metals ◽

Analytical Description ◽

Specific Electrical Conductivity ◽

Molten Metals ◽

Specific Electric Conductivity ◽

Metal Melts ◽

Relationship Of ◽

The Relationship

The paper presents an analytical description of the relationship of the specific electrical conductivity æ of individual alkali metals haloganides melts (MHal) (M – Li, Na, K, Rb, Cs, Fr; Hal – F, Cl, Br, I) and the specific electrical conductivity æ(M) of alkali metal melts for temperatures (Тпл + n) (Tпл – melting temperature K; n = 5, 10, 50, 75, 100, 150, 200° higher melting temperatures of MHal and metals) and the specific electrical conductivity of alkali metals at standard temperature using M.Kh. Karapetyans comparative methods. The relationship of properties æ(MHal при Тпл+n) = f(æ(MHal при Тпл+5)), æ(FrHalТпл+n) = f(æ(FrHalТпл+5°)) is described in the "property-property" coordinates. A comparative analysis of the specific electrical conductivity values of francium haloganides melts obtained by the proposed methods was carried out. The possibility of calculating the electrical conductivity of molten salts from the electrical conductivity of molten metals is shown. It is shown that the equation æ(MHal)0.5 = a + bæ(M)1.5 can be used to calculate the specific electrical conductivity of francium haloganides melts. The calculation of the specific electrical conductivity using various equations shows the consistency of the numerical values obtained.

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Properties of Starch Based Foams Made by Thermal Pressure Forming

Acta Polytechnica ◽

10.14311/1073 ◽

2008 ◽

Vol 48 (6) ◽

Author(s):

J. Štancl ◽

J. Skočilas ◽

J. Šesták ◽

R. Žitný

Keyword(s):

Electrical Conductivity ◽

Heat Capacity ◽

Electric Conductivity ◽

Ohmic Heating ◽

Potato Starch ◽

Electrical Heating ◽

Specific Electrical Conductivity ◽

Indirect Contact ◽

Heated Sample ◽

Contact Heating

Packaging materials based on expanded polystyrene can be substituted by biodegradable foam, manufactured by direct or indirect electrical heating of a potato starch suspension in a closed mold. This paper deals with an experimental evaluation of selected properties of potato starch and starch foam related to this technology: density, specific heat capacity and specific electrical conductivity of a water suspension of potato starch within the temperature range up to 100 °C, and mass fraction from 5 to 65 %. The electric conductivity and heat capacity changes were observed during direct ohmic heating of a starch suspension between electrodes in a closed cell (feeding voltage 100 V, frequency 50 Hz). Specific electric conductivity increases with temperature, with the exception of the gelatinization region at 60 to 70 °C, and decreases with increasing concentration of starch (the temperature and concentration dependencies were approximated using the Lorentz equation). Direct ohmic heating is restricted by a significant decrease in effective electrical conductivity above a temperature of 100 °C, when evaporated steam worsens the contact with the electrodes. Experiments show that when direct ohmic heating is not combined with indirect contact heating, only 20 % of the water can be evaporated from manufactured samples and the starch foam is not fully formed. This is manifested by only a slight expansion of the heated sample. Only the indirect contact heating from the walls of the mold, with the wall temperature above 180 °C, forms a fixed porous structure (expansion of about 300 %) and a crust, ensuring suitable mechanical and thermal insulation properties of the manufactured product. The effective thermal conductivity of the foamed product (sandwich plates with a porous core and a compact crust) was determined by the heated wire method, while the porosity of the foam and the thickness of the crust were evaluated by image analysis of colored cross sections of manufactured samples. While the porosity is almost constant, the thickness of the crust is approximately proportional to the thickness of the plate.

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БЕЗКОНТАКТНИЙ МЕТОД ТРИПАРАМЕТРОВОГО ВИМІРЮВАЛЬНОГО КОНТРОЛЮ ФІЗИКО-ХІМІЧНИХ ХАРАКТЕРИСТИК ЗРАЗКА ФЕРОМАГНІТНОЇ РІДИНИ

Bulletin of the Kyiv National University of Technologies and Design Technical Science Series ◽

10.30857/1813-6796.2018.4.8 ◽

2018 ◽

Vol 124 (4) ◽

pp. 77-84

Author(s):

В. В. Себко ◽

В. Г. Здоренко

Keyword(s):

Electrical Conductivity ◽

Magnetic Permeability ◽

Electromagnetic Method ◽

Specific Electrical Conductivity ◽

Parameter Method ◽

Chemical Characteristics ◽

Parameter Control ◽

Relative Magnetic Permeability ◽

Physical And Chemical ◽

Measuring Control

The aim of the article is to investigate the method of three-parameter control of a sample of a ferromagnetic liquid, the realization of which is carried out on the basis of a noncontact transformer electromagnetic converter (TEC) with samples of ferromagnetic liquids in a longitudinal magnetic field.We used a technique for studying samples of a ferromagnetic liquid for the realization of a three-parameter electromagnetic method for measuring the physical and chemical characteristics of ferromagnetic liquids based on thermal TEC. The three-parameter method of measuring control of the relative magnetic permeability mr, the specific electrical conductivity σ, and the temperature t of a sample of a ferromagnetic liquid, which is monitored on the basis of measurements and analysis of signals of a thermal contactless three-parameter TEC, is studied. The theoretical principles of the operation of a contactless thermal TEC with a sample of a ferromagnetic liquid are based on the realization of a three-parameter method for measuring the monitoring of magnetic, electrical, and temperature parameters.

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SiO2 Promoted CaO Diffusion to C Phase at 1500 and 1700 °C

Energies ◽

10.3390/en14030587 ◽

2021 ◽

Vol 14 (3) ◽

pp. 587

Author(s):

Lijuan Ni ◽

Renxing Wang ◽

Qingya Liu ◽

Junfei Wu ◽

Yue Pan ◽

...

Keyword(s):

Mass Transfer ◽

Close Contact ◽

Chemical Changes ◽

Physical And Chemical ◽

Diffusion Behaviors

To better understand the mass transfer behaviors in CaC2 production from CaO and coke, this paper studies the diffusion behaviors of CaO and graphite, with or without ash, at 1500 and 1700 °C. CaO and graphite are pressed into tablets and heated alone or in close contact. Physical and chemical changes in these tablets are analyzed by XRD and SEM+EDX. In some experiments, thin Mo wires are placed between the closely contacted CaO and graphite tablets to identify the diffusion direction. It is found that the diffusion between CaO and low-ash graphite is very limited. SiO2 in a high-ash graphite diffuses into CaO tablet and reacts with CaO to form Ca2SiO4, which then diffuses into the graphite tablet easily and leads to CaC2 formation at 1700 °C.

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Nanobiotechnology: Nature-inspired silver nanoparticles towards green synthesis

Energy & Environment ◽

10.1177/0958305x21989883 ◽

2021 ◽

pp. 0958305X2198988

Author(s):

Nur Syakirah Rabiha Rosman ◽

Noor Aniza Harun ◽

Izwandy Idris ◽

Wan Iryani Wan Ismail

Keyword(s):

Electrical Conductivity ◽

Silver Nanoparticles ◽

Green Synthesis ◽

Metal Nanoparticles ◽

Current Trend ◽

Biological Properties ◽

Noble Metal Nanoparticles ◽

Current Application ◽

Physical Chemical ◽

Physical And Chemical

The emergence of technology to produce nanoparticles (1 nm – 100 nm in size) has drawn significant researchers’ interests. Nanoparticles can boost the antimicrobial, catalytic, optical, and electrical conductivity properties, which cannot be achieved by their corresponding bulk. Among other noble metal nanoparticles, silver nanoparticles (AgNPs) have attained a special emphasis in the industry due to their superior physical, chemical, and biological properties, closely linked to their shapes, sizes, and morphologies. Proper knowledge of these NPs is essential to maximise the potential of biosynthesised AgNPs in various applications while mitigating risks to humans and the environment. This paper aims to critically review the global consumption of AgNPs and compare the AgNPs synthesis between conventional methods (physical and chemical) and current trend method (biological). Related work, advantages, and drawbacks are also highlighted. Pertinently, this review extensively discusses the current application of AgNPs in various fields. Lastly, the challenges and prospects of biosynthesised AgNPs, including application safety, oxidation, and stability, commercialisation, and sustainability of resources towards a green environment, were discussed.

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Electrical Conductivity of Chloro(phenyl)glyoxime and Its Co(II), Ni(II) and Cu(II) Complexes

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20031233 ◽

2003 ◽

Vol 68 (7) ◽

pp. 1233-1242 ◽

Cited By ~ 6

Author(s):

Orhan Turkoglu ◽

Mustafa Soylak ◽

Ibrahim Belenli

Keyword(s):

Electrical Conductivity ◽

Temperature Dependence ◽

Electric Conductivity ◽

Crystal Structures ◽

Elemental Analysis ◽

Analysis Data ◽

Elemental Analysis Data ◽

The Stability ◽

Xrd Patterns ◽

Metal Ligand

Chloro(phenyl)glyoxime, a vicinal dioxime, and its Ni(II), Cu(II) and Co(II) complexes were prepared. XRD patterns of the complexes point to similar crystal structures. IR and elemental analysis data revealed the 1:2 metal-ligand ratio in the complexes. The Co(II) complex is a dihydrate. Temperature dependence of electrical conductivity of the solid ligand and its complexes was measured in the temperature range 25-250 °C; it ranged between 10-14-10-6 Ω-1 cm-1 and increased with rising temperature. The activation energies were between 0.61-0.80 eV. The Co(II) complex has lower electric conductivity than the Ni(II) and Cu(II) complexes. This difference in the conductivity has been attributed to differences in the stability of the complexes.

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