scholarly journals Electrophysical characteristics and dielectric constant of soils of northern natural forests of Ukrainian steppe zone

2019 ◽  
Vol 19 (2) ◽  
pp. 45-50
Author(s):  
V. A. Gorban
Keyword(s):  
Electrical Conductivity ◽  
Dielectric Constant ◽  
Electrical Resistance ◽  
Steppe Zone ◽  
Water Soluble ◽  
Natural Forests ◽  
The One ◽  
Aggregate Composition ◽  
Short Time ◽  
To Receive

Currently in soil science the search for new methods and technologies for soil research is relevant, which in a short time allows to receive a large amount of information about its condition with the lowest financial cost. Methods for determining electrophysical parameters and dielectric constant of soils are conforming to these requirements. As a result of the investigations, it was found that the upper horizons of the soils of Glubokiy ravine, located in the Ukrainian steppe zone (Novomoskovsk district, Dnipropetrovsk region, Ukraine), differ to lower values of electrical resistance and dielectric constant compared to the lower horizons. The upper horizons are characterized by increased values of electrical conductivity, mineralization and salinity compared with the lower horizons. Sudden changes in the values of all investigated parameters at the boundary of the eluvial and illuvial horizons were found in Luvic phaeozem of northern exposition of ravine and in Luvic gleyic phaeozem of thalweg. In the Luvic phaeozem of the forest northern exposure of the ravine and in the Luvic gleyic phaeozem of the leveled area of the ravine, sharp changes were found in the values of all the investigated parameters at the boundary of the eluvial and illuvial horizons. In the eluvial horizons of Luvic phaeozem, which bordering on the illuvial horizons, a sharp increase in the dielectric constant is observed. The upper horizons of Calcic chernozem of the northern ravine exposition are characterized by increased values of electrical resistance, electrical conductivity and dielectric constant, as well as lower values of mineralization and salinity compared to the upper horizons of Calcic chernozem of the southern ravine exposition. The upper horizons of the Luvic phaeozem of the forest north exposition of the ravine are characterized by higher values of electrical resistance and dielectric constant compared to the upper horizons of the Luvic phaeozem of the forest south exposition of the ravine. In terms of electrical conductivity, mineralization and salinity, Luvic phaeozems practically don’t differ. The upper horizons of Luvic phaeozems are characterized by lower values of electrical resistance and dielectric constant, as well as higher values of electrical conductivity, mineralization and salinity compared to Calcic chernozems. The results obtained indicate that the highest content of organic matter and water-soluble compounds, as well as the best structurally-aggregate composition, and also the best structural-aggregate composition is characteristic of forest chernozem. This is due to the one that formed on the southern exposition of the ravine and which is characterized by the lowest values of dielectric constant and electrical resistance, as well as the highest values of electrical conductivity, mineralization and salinity.

scholarly journals Synthesis of (Poly-methyl Methacrylate-lead Oxide) Nanocomposites and Studying their A.C Electrical Properties for Piezoelectric Applications

2018 ◽  
Vol 7 (4) ◽  
pp. 547-551
Author(s):  
Dalal Hassan ◽  
Ahmed Hashim
Keyword(s):  
Electrical Conductivity ◽  
Dielectric Constant ◽  
Dielectric Loss ◽  
Methyl Methacrylate ◽  
Electrical Resistance ◽  
Lead Oxide ◽  
Piezoelectric Materials ◽  
Oxide Nanoparticles ◽  
Poly Methyl Methacrylate ◽  
Increase With Increase

Piezoelectric materials have been prepared from (poly-methyl methacrylate-lead oxide) nanocomposites for electronic applications. The lead oxide nanoparticles were added to poly-methyl methacrylate by different concentrations are (4, 8, and 12) wt%. The structural and dielectric properties of nanocomposites were studied. The results showed that the dielectric constant and dielectric loss of nanocomposites decrease with increase in frequency of applied electric field. The A.C electrical conductivity increases with increase in frequency. The dielectric constant, dielectric loss and A.C electrical conductivity of poly-methyl methacrylate increase with increase in lead oxide nanoparticles concentrations. The results of pressure sensor showed that the electrical resistance of (PMMA-PbO2) nanocomposites decreases with increase in pressure.

scholarly journals Fabrication and studying the dielectric properties of (polystyrene-copper oxide) nanocomposites for piezoelectric application

2019 ◽  
Vol 8 (1) ◽  
pp. 52-57 ◽  
Author(s):  
Dalal Hassan ◽  
Ahmed Hashim Ah-yasari
Keyword(s):  
Electrical Conductivity ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Electrical Properties ◽  
Dielectric Loss ◽  
Copper Oxide ◽  
Electrical Resistance ◽  
Copper Oxide Nanoparticles ◽  
Oxide Nanoparticles ◽  
Increase With Increase

The preparation of (polystyrene-copper oxide) nanocomposites have been investigated for piezoelectric application. The copper oxide nanoparticles were added to polystyrene by different concentrations are (0, 4, 8 and 12) wt.%. The structural and A.C electrical properties of (PS-CuO) nanocomposites were studied. The results showed that the dielectric constant and dielectric loss of (PS-CuO) nanocomposites decrease with increase in frequency. The A.C electrical conductivity increases with increase in frequency. The dielectric constant, dielectric loss and A.C electrical conductivity of polystyrene increase with increase in copper oxide nanoparticles concentrations. The results of piezoelectric application showed that the electrical resistance of (PS-CuO) nanocomposites decreases with increase in pressure.

scholarly journals Structural and aggregate composition features of southern variant natural forest edaphotopes of Ukrainian steppe zone

2020 ◽  
Vol 31 (1) ◽  
pp. 16-22
Author(s):  
V. A. Gorban ◽  
K. S. Kuptsova ◽  
N. S. Ostrianyn ◽  
O. G. Tetiukha
Keyword(s):  
Forest Soil ◽  
Sharp Decrease ◽  
Steppe Zone ◽  
Illuvial Horizon ◽  
Natural Forests ◽  
Fraction Size ◽  
National University ◽  
Porous Part ◽  
Aggregate Composition ◽  
Intermediate Value

The natural forests of the southern variant of the steppe zone of Ukraine (according to the classification of O. L. Belgard) are located on the territory of the former porous part of the Dnieper. The properties of edaphotopes of these forests were studied in detail by the staff of the Comprehensive expedition of the Oles Honchar Dnipro National University for the study of forests in the steppe zone of Ukraine (A. P. Travleev, N. A. Bilova, A. A. Dubina, K. M. Bozhko). However, there are no data on the structural and aggregate composition of the genetic horizons of edaphotopes of natural forests of the southern variant of the steppe zone of Ukraine, established by classical methods of determination. This work is devoted to the coverage of these features. As a result of research it is established that the best conditions for the formation of structural aggregates are characteristic of the upper horizons of all studied soils and especially for the forest chernozem in the conditions of northern exposure. The highest content of agronomically valuable structural aggregates is characterized by forest chernozem in the conditions of northern exposure of the ravine, the lowest – meadow-forest soil of thalweg, and forest chernozem in the conditions of southern exposure occupies an intermediate value. The eluvial horizons of ravine edaphotopes differ most contrastingly from the illuvial horizons in the conditions of northern and southern exposures. Eluvial horizons are characterized by a reduced fraction content of > 10 mm and increased values ​​of the structural coefficient compared to illuvial horizons. In the thalweg, these differences are not so clear. The upper horizons have an increased content of water-resistant fraction size > 5 mm compared to the horizons below. With depth in all studied edaphotopes there is an increase in the content of the fraction size < 0.25 mm with depth. Among the upper horizons, the highest content of water-resistant fraction size > 5 mm and the lowest content of fraction < 0.25 mm differs meadow-forest soil in thalweg conditions. Very close to the meadow-forest soil in terms of the values ​​of the respective fractions is forest chernozem in the conditions of northern exposure. Forest chernozem in the conditions of southern exposure differs by the lowest content of water-resistant fraction size > 5 mm and the highest content of fraction size < 0.25 mm among all studied soils. Eluvial horizons of forest chernozems of northern and southern exposures differ from illuvial horizons by reduced content of water-resistant fractions of > 5 and 5–3 mm. The eluvial horizons of the meadow-forest soil of the thalweg differ from the illuvial horizon by a sharp decrease in the content of the water-resistant fraction of 1–0.5 mm. A comparative analysis of the structural and aggregate composition of the studied edaphotopes revealed that the best conditions for the formation of agronomically valuable fractions are characteristic of the forest chernozem of the northern exposure. As a result of comparing the characteristics of eluvial and illuvial horizons, it was found that the change of eluvial process to illuvial is accompanied by a sharp decrease in forest chernozems content of agronomically valuable fractions during dry sieving, as well as an increase in water resistance. In meadow-forest soils, this transition is characterized by a sharp decrease in the content of agronomically valuable fractions in the illuvial horizon during wet sieving compared to the eluvial horizon.

Global Economic Crisis of 2008-2009: Sources and Roots

2009 ◽  
pp. 18-31
Author(s):  
G. Rapoport ◽  
A. Guerts
Keyword(s):  
Oil And Gas ◽  
Trade Deficit ◽  
Developed Countries ◽  
The Other ◽  
Energy Resources ◽  
Market Mechanisms ◽  
Production Output ◽  
The One ◽  
To Receive ◽  
Partial Destruction

In the article the global crisis of 2008-2009 is considered as superposition of a few regional crises that occurred simultaneously but for different reasons. However, they have something in common: developed countries tend to maintain a strong level of social security without increasing the real production output. On the one hand, this policy has resulted in trade deficit and partial destruction of market mechanisms. On the other hand, it has clashed with the desire of several oil and gas exporting countries to receive an exclusive price for their energy resources.

Der Erzieher als Manager

2019 ◽  
Vol 95 (4) ◽  
pp. 517-530
Author(s):  
Diana Lohwasser
Keyword(s):  
Educational Process ◽  
The Other ◽  
Critical View ◽  
Other Hand ◽  
The One ◽  
Short Time ◽  
Time Diagnosis

Abstract The Educator as a Manager. A Critical View In the following article tasks and motifs of the educator as manager are described. It is clear that there are other educator metaphors and associated behaviors. To some extent, the actions of the different educator metaphors overlap, but they differ in their purpose and perspective on the educational process and the person to be educated. First, a short time diagnosis is made, which describes the context of this metaphor of the educator as manager. Subsequently, on the one hand, the various motifs, tasks and objectives of an educator as manager are discussed. On the other hand, it is asked if it is possible in the current discourse to take a different perspective on the educational process.

scholarly journals Deep Learning Approach for Vibration Signals Applications

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3929
Author(s):  
Han-Yun Chen ◽  
Ching-Hung Lee
Keyword(s):  
Surface Roughness ◽  
Tool Wear ◽  
Parameters Optimization ◽  
Frequency Spectra ◽  
Vibration Signals ◽  
Bearing Faults ◽  
Time Frequency ◽  
And Performance ◽  
The One ◽  
Short Time

This study discusses convolutional neural networks (CNNs) for vibration signals analysis, including applications in machining surface roughness estimation, bearing faults diagnosis, and tool wear detection. The one-dimensional CNNs (1DCNN) and two-dimensional CNNs (2DCNN) are applied for regression and classification applications using different types of inputs, e.g., raw signals, and time-frequency spectra images by short time Fourier transform. In the application of regression and the estimation of machining surface roughness, the 1DCNN is utilized and the corresponding CNN structure (hyper parameters) optimization is proposed by using uniform experimental design (UED), neural network, multiple regression, and particle swarm optimization. It demonstrates the effectiveness of the proposed approach to obtain a structure with better performance. In applications of classification, bearing faults and tool wear classification are carried out by vibration signals analysis and CNN. Finally, the experimental results are shown to demonstrate the effectiveness and performance of our approach.

scholarly journals A Water-Soluble Copper-Immobilized Covalent Organic Framework Functioning as an “OFF–ON” Fluorescent Sensor for Amino Acids

2021 ◽  
Author(s):  
Lamiaa Reda Ahmed ◽  
Ahmed F. M. EL-Mahdy ◽  
Cheng-Tang Pan ◽  
Shiao-Wei Kuo
Keyword(s):  
Amino Acids ◽  
Fluorescent Sensor ◽  
Water Soluble ◽  
One Pot ◽  
Covalent Organic Framework ◽  
The One ◽  
Organic Framework

In this paper, we describe the construction of a new fluorescent hydroxyl- and hydrazone-based covalent organic framework (TFPB-DHTH COF) through the one-pot polycondensation of 1,3,5-tris(4-formylphenyl)benzene (TFPB) and 2,5-dihydroxyterephthalohydrazide (DHTH) under...

Effect of High-Energy Ball-Milling and TiB2 Content on Microstructures and Properties of Cu-TiB2 Composites Sintered by SPS

2006 ◽  
Vol 118 ◽  
pp. 661-665 ◽  
Author(s):  
Dae Hwan Kwon ◽  
Thuy Dang Nguyen ◽  
Pyuck Pa Choi ◽  
Ji Soon Kim ◽  
Young Soon Kwon
Keyword(s):  
Electrical Conductivity ◽  
Ball Milling ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Energy Ball ◽  
Xrd Patterns ◽  
Short Time ◽  
Tib2 Particles

The microstructure and properties of Cu-TiB2 composites produced by high-energy ball-milling of TiB2 powders and spark-plasma sintering (SPS) were investigated. TiB2 powders were mechanically milled at a rotation speed of 1000rpm for short time in Ar atmosphere, using a planetary ball mill. To produce Cu-xTiB2 composites( x = 2.5, 5, 7.5 and 10wt.% ), the raw and milled TiB2 powders were mixed with Cu powders by means of a turbular mixer, respectively. Sintering of mixed powders was carried out in a SPS facility under vacuum. High-energy ball-milling resulted in refinement of TiB2 particles. XRD patterns of milled TiB2 powders indicated broader TiB2 peaks with decreased intensities. After sintering at 950 for 5min using the raw and milled TiB2 mixture powders, the sintered density decreased with increasing TiB2 content regardless of milling of TiB2. In the case of raw TiB2, hardness rapidly increased from 4 to 44 HRB with increasing TiB2 content. The electrical conductivity changed from 95.5 to 80.7 %IACS. For mixtures of Cu powders with milled TiB2 powders, hardness increased from 38 to 67 HRB as TiB2 content increased, while the electrical conductivity varied from 88% to 51 % IACS. When compared to compacts sintered with raw and milled TiB2 powders, the electrical conductivity of specimens with raw TiB2 powder was higher than that of specimens with milled TiB2 powder, while hardness was slightly lower.

Acid Volatile Sulfide (AVS) and Simultaneously Extracted Metals (SEM) in Surface Sediments of Chaohu Lake, Anhui Province, China

2013 ◽  
Vol 779-780 ◽  
pp. 1213-1219
Author(s):  
Shu Qin Chen ◽  
Lei Zhang ◽  
Zhao Sheng Chu ◽  
She Rong Hu
Keyword(s):  
Surface Sediments ◽  
Local Scale ◽  
Acid Volatile Sulfide ◽  
Anthropogenic Factors ◽  
Chaohu Lake ◽  
Lake Surface ◽  
Different Seasons ◽  
The One ◽  
Short Time ◽  
Spot 5

At present there are few studies on the AVS and SEM in sediments of Chaohu Lake. Most of the previous studies on heavy metals based on the one time, the short-time or a local-scale survey. In this paper, [AVS] and [SEM] in Chaohu Lake surface sediments were studied for different seasons in 2007, 2008 and 2009. The results showed that: (a) The three-year average of [AV and [ΣSE in surface sediments of Chaohu Lake is 4.2μmolg-1and 2.31μmolg-1, respectively. The maximum of [AV appears on spot 5 (14.845μmolg-1) in summer while the minimum appears on spot 9 (0.13μmolg-1) in winter. (b) In spot 5 which near the estuary of Yuxi River, three-year average of [SE was the maximum (5.81μmolg-1), and the minimum of [ΣSE (0.07μmolg-1) appears on spot 8 which locates in the middle of Chaohu Lake. In spot 13 the [ΣSEM]-[AVS]=3.2>2 and [ΣSEM]/[AVS]=4.45>2.34 indicate that heavy metal contaminants from Hefei city have threatened the biosafety of Chaohu Lake. (c) The spatial autocorrelation of SEMCdis weak, which indicates that spatial distribution of SEMCdis determined by anthropogenic factors rather than sediments' own attribute. Chaohu Lake has been heavily polluted by Cd from no-point source and electronic electroplating industry.

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