BazTech - Yadda

1

Surrogate methods for determining profiles of material properties of planar test objects with accumulation of apriori information about tchem

Halchenko Volodymyr Y., Trembovetska Ruslana, Tychkov Volodymyr, Tychkova Nataliia

Archives of Electrical Engineering

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2024

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Vol. 73, nr 1

183--200

EN

New methods for identifying the material properties of planar objects as a result of measurements by the eddy current method are proposed. The methods are based on the latest surrogate strategies and advanced optimization techniques that improve efficiency and reduce resource consumption of problem solutions, and balance computational complexity with the accuracy of the results. High-performance metamodels for global surrogate optimization are based on deep truly meaningful fully connected neural networks, serving as an additional function of accumulating apriori information about objects. High accuracy of the approximation of the multidimensional response surface, which is determined by the “exact” electrodynamic model of the testing process, is ensured by performing calculations according to the computer design of a homogeneous experiment with a low weighted symmetric centered discrepancy. The results of numerical experiments performed for full and reduced dimensional search spaces, which can be obtained by linear transformations using the principal component method, are presented. The verification of the methods proved their sufficiently high accuracy and computational performance.

2

A comprehensive review of the salinity assessment in groundwater resources of Iran

Mohammadi Arasteh Saeed, Shoaei Seyyed Mohammad

Acta Geophysica

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2024

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Vol. 72, no. 1

385--403

EN

The main purpose of the present research is to propose a comprehensive attitude of the salinity in groundwater resources of Iran using 116 papers in the assessment of groundwater quality in different areas of the country. The conducted study contains the measurement of the values of physicochemical parameters of which electrical conductivity (EC), as the fundamental parameter for salinity determination of groundwater, was considered mostly, and by comparing it with standards, as well as employing the Wilcox diagram, the quality of water was assessed for drinking and agricultural purposes, respectively. Study of the previous papers revealed that in only the west and northwest of the country, the groundwater quality was suitable for drinking, and in the majority of provinces, EC values exceeded the recommended limits. The highest EC level was seen in central provinces which led to the aggravation of groundwater and the largest proportion of salinity, putting the quality of water in an unsuitable class for drinking. Additionally, the assessment of groundwater quality for irrigation uses using the Wilcox diagram showed high and very high salinity rates in most areas of the study area. Northwestern provinces relatively had the lowest level putting in C3-S1 class, while central areas reached the highest with C4-S4 classification. Deficiency of rainfall, high rate of groundwater exploitation, and the intrusion of saltwater from Salt Lake were the principal reasons for groundwater deterioration in central parts of the study area.

3

Synthesis and characterization of aldamine condensed Schiff bases and their iron salts

Meng Chao, Gu Zheng, Wang Jianfa, Sui Jinyong, Hu Shaokai, Zhang Susu, Zhang Xiaoyi, Li Peiyao, Liu Wenjin, Hu Yifan

Polimery

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2023

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Vol. 68, nr 2

99--105

EN

Two types of long-chain conjugated Schiff bases and their iron salts were obtained by the coordination polycondensation of p-phenylenediamine with glyoxal or terephthalaldehyde. Elemental analysis and infrared spectroscopy (FTIR) were used to evaluate the chemical structure of the obtained poly(Schiff bases) and their salts. Thermal stability (TGA) and electrical conductivity were also investigated.

PL

W wyniku koordynacyjnej polikondensacji p-fenylenodiaminy z glioksalem lub aldehydem tereftalowym otrzymano dwa rodzaje długołańcuchowych sprzężonych zasad Schiffa oraz ich sole żelazowe. Do oceny struktury chemicznej otrzymanych zasad Schiffa i ich soli stosowano analizę elementarną i spektroskopię w podczerwieni (FTIR). Zbadano również stabilność termiczną (TGA) i przewodnictwo elektryczne.

4

Evaluating the suitability of a new telemetric capacitance-based measurement system for real-time application in irrigation and fertilization management

Treder Waldemar, Klamkowski Krzysztof, Tryngiel-Gać Anna, Wójcik Katarzyna

Journal of Water and Land Development

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2023

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no. 56

67--73

EN

The suitability of a new wireless smart farming system for controlling irrigation and fertilization of horticultural plants was assessed in the study. The system (name: AGREUS® ) includes sensors (soil moisture, salinity, weather data), executive modules (valve modules), and an application available on the web portal (accessed through computers and mobile devices). The studies were performed under laboratory and field conditions. Laboratory tests included appraisal of the precision of soil moisture and salinity measurements carried out with the soil probe (comparison with the results obtained by laboratory methods). Operational tests were conducted in field trials. In these trials, assessment of the possibility of practical control of irrigation and monitoring soil salinity was performed in an apple orchard. The conducted analyses have shown the usefulness of the system, not only for automatic control of irrigation but also for making decisions about the necessity to fertilize plants. The system enables continuous monitoring of changes in soil moisture and salinity, including the migration of minerals across the soil profile (using a probe with several measuring elements) as a result of the applied irrigation or rainfall. The system allows for automatic application of irrigation or fertigation depending on the adopted soil moisture and salinity thresholds. However, the tests showed that a salinity index calculated by the system does not directly correspond to the salinity values determined by laboratory methods. For this reason individual interpretation and determination of optimal ranges for plants is required.

5

Research on the Performance of Polypyrrole Coated Conductive Fabrics Prepared from Different Base Materials

Liu Yuanjun, Xue Huangyu, Liu Yanyan, Zhao Jiaqi, Wu Haiying, Zhao Xiaoming

Fibres & Textiles in Eastern Europe

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2023

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Vol. 31, no. 2

75--81

EN

In this paper, polypyrrole coated conductive fabrics were prepared using pyrrole as the monomer, p-toluene sulfonic acid as the doping agent and ammonium persulfate as the oxidant, adopting the simple method of situ polymerization of the liquid phase. Six types of conductive polypyrrole coated fabrics were prepared adopting polyester-cotton blended fabrics, nylon fabrics, wool fabrics, silk fabrics, basalt fabrics and aramid fabric respectively as base materials and using the same process conditions; its electrical conductivity was compared, and the distribution and resistance of the washing fastness of polypyrrole on the surface of those fabrics were studied. Results showed that under the same process conditions, the conductivity of polypyrrole coated terylene fabrics was the best, followed by the polypyrrole coated nylon fabrics and polypyrrole coated wool fabrics. Observed by electron microscope, the distribution of polypyrrole was more homogeneous on different base cloths. After washing, it was concluded that the combination fastness of polypyrrole with polyester-cotton, nylon and wool was better, while the combination fastness of polypyrrole with basalt and aramid was poor.

6

The Study of the Germination Behavior of Forage Species on Substrates Taken from the Soil of Awleigatt National Park in Mauritania

Abidine Mohamed Mahmoud, Cheikh Lemane Mohamed, Dallahi Youssef, Baba Mohamed Lemine, Mahmoud El Weila Mohamed, Soulé Ahmedou, Vadel Ahmedou

Ecological Engineering & Environmental Technology

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2023

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Vol. 24, iss. 6

257--269

EN

Awleigatt National Park (ANP) is a zoological site ensuring both the conservation and restoration of biodiversity on a national scale. In this perspective, the ANP has set as one of its ambitious objectives the autonomy in fodder needs. The objective of this work was to study the adaptability of three forage species (Medicago sativa, Acacia senegal and Dolichos lablab) to the edaphic conditions of the NAP. The adopted approach was to characterize three types of representative ANP soil substrates in order to develop an interpolation map of EC conductivity and pH data. Subsequently, the germination behavior of the three species was studied in the laboratory on three substrates taken from the study area (Dune, Dune flank and Interdune) in the absence and presence of NaCl (0, 50 and 100 Mm). The obtained results show that the soils are basic and the electrical conductivity is higher in the inter-dune substrate. The mapping of the study area corroborates the experimentally obtained data. Germination behavior shows that germination is best on dune and dune flank substrates. The addition of high concentrations of NaCl (100mM) shows that Dolichos lablab is the most resistant to salinity. Medicago sativa and Acacia senegal show low germination capacity both in the absence and in the presence of NaCl, most likely reflecting a low embryonic longevity of the seeds used. The parameters deduced from the germination kinetics curve show that the adverse effect of salinity in the three species is observed at all three germination phases (TL, GSS and CG). As a result, the effect of salinity on germination of all three species is both osmotic and toxic.

7

Long-term water quality monitoring using Sentinel-2 data, Głuszyńskie Lake case study

Ciężkowski Wojciech, Frąk Magdalena, Kardel Ignacy, Kościelny Marcin, Chormański Jarosław

Przegląd Naukowy Inżynieria i Kształtowanie Środowiska

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2022

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Vol. 31, No. 4

283--293

EN

This study shows the results of long-term inland water monitoring using Sentinel-2 data for Głuszyńskie Lake in the years 2015–2022. Four water quality parameters: biological oxygen demand (BOD), dissolved organic carbon (DOC), chlorophyll concentration (CHL) and electrical conductivity (EC) were calculated according to formulas found in the literature. The results were validated based on measurements conducted in 2021 and 2022, where for BOD, DOC and CHL high determination coefficients (0.77 and 0.79) were observed, and the EC determination coefficient was equal to 0.45. The results show that empirical formulas can be used for qualitative analyses of inland water quality, while for quantitative analyses more extensive field work needs to be performed.

8

Agronomic evaluation of irrigation water on the Southern Buh and Kamianska irrigation systems

Chornyy Sergiy, Isaiva Vera

Journal of Water and Land Development

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2022

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no. 54

77--83

EN

The aim of the research was to study the temporal and spatial dynamics of a set of agronomic criteria for irrigation water in the process of transporting it from the Southern Buh River intake site to the lands of the Southern Buh and Kamianska irrigation systems situated in southern Ukraine. Six stationary research sites for monitoring the quality of irrigation water were established along the route of irrigation water transportation. Determination of agronomic criteria for irrigation water quality was carried out in two terms: at the beginning of the irrigation season, in May, and at the end, in September. The content of cations of sodium, magnesium, calcium, and anions of chlorine, sulphates, carbonates, and bicarbonates was determined. In the field, the pH and electrical conductivity of water, the total salt content, and the total amount of dissolved solids were determined. It is determined that waters have an average level of danger from the point of view of salinisation of soils. This fact leads to a decrease in yield of sensitive to salinity crops (corn, alfalfa and most vegetables). The high content of sodium cations along with the low content of calcium and magnesium cations indicates the danger of degradation of the physical properties of the southern chernozems and the need to use the meliorants containing calcium. There is a high probability of toxic effects on crops caused by sodium cations. At the same time, it is stated that there is no negative effect of chlorine anions on plants.

9

Four-parameter electromagnetic method for determining the parameters of brewery effluents

Sebko V. V., Pyrozhenko Ye. V., Zashchepkina N. M., Zdorenko V. G., Markina O. M.

Journal of Achievements in Materials and Manufacturing Engineering

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2022

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Vol. 113, nr 2

49--64

EN

Purpose: of the article is to study a four-parameter electromagnetic method for joint measurements of electrical resistivity k, relative permittivity εr, temperature t and density ρ of samples of acidic, alkaline and average effluents from a microbrewery based on a magnetic flux probe (MFP), which considers the influence of informative parameters of beer effluents on the components of the amplitude and phase signals of a multiparameter device. Design/methodology/approach: The implementation of the four-parameter method is carried out on the basis of the dependences G1 = f (A1) and G2 = f (A2) at two frequencies of the electromagnetic field f0 and f1 for acid, alkaline and average effluent and allows you to jointly determine the four parameters of effluent samples with the same converter in the same control area. The proposed method makes it possible to improve the accuracy of identifying effluent samples since the obtained multiparameter information makes it possible to determine the nature and properties of effluent samples using only one transducer with certain physical characteristics. The research results lead to the expansion of the technical capabilities of electromagnetic measurement methods, as well as to an increase in the metrological characteristics of electromagnetic transducers and an increase in the accuracy of measuring the parameters of effluent samples compared to reference methods and measuring instruments. Thus, the implementation of this approach contributes to the prediction and prevention of the reasons for the deviation of beer effluent samples from the specified indicators of environmental safety. Findings: The universal conversion functions MFP have been established, connecting the amplitude and phase components of the converter signals with the parameters k, εr, t and ρ of acidic, alkaline and average effluents. Based on the universal transformation functions G1 = f (A1) and G2 = f (A2), a four-parameter electromagnetic method for joint measurements of electrical resistivity k, relative permittivity εr, temperature t and density ρ of acidic, alkaline, and average effluents from breweries has been developed. When conducting research at two close frequencies of the electromagnetic field f0 = 20.3 MHz and f1 = 22 MHz, algorithms were obtained for measuring and calculating procedures for determining k, εr, t and ρ for samples of acidic, alkaline and average effluents from the brewing industry. Research limitations/implications: Research perspectives consist in the creation of automated systems for multiparameter measuring control of the physicochemical characteristics of acidic and alkaline effluent from food and processing industries based on the immersed electromagnetic transducer. Based on the data obtained using informative methods to measure the parameters of effluent samples, an integrated method for treating beer effluents of various compositions will be proposed. At the same time, the scheme of the integrated treatment method should include a filter that provides the introduction of a magnetic fluid and a separation device that allows us to remove a fraction, including pollution in itself. Practical implications: Is that the proposed four-parameter electromagnetic method makes it possible to determine to what composition the controlled samples of wastewater should be attributed (acidic or alkaline). It, in turn, makes it possible to choose a rational method for treating beer effluents and to prevent the reasons for the deviation of effluent samples from the environmental safety indicators set by the standards. Originality/value: of the article is the research related to the expansion of the functional and technical capabilities of the electromagnetic two-frequency transducer MFP through the implementation of a four-parameter electromagnetic method of joint measurements of electrical resistivity k, relative permittivity εr, temperature t and density ρ of acidic, alkaline and average effluents from breweries. The universal transformation functions G1 = f (A1) and G2 = f (A2) found in the work at two close magnetic field frequencies, f0 = 20.3 MHz and f1 = 22 MHz, make it possible to control four physicochemical parameters of acidic, alkaline and average wastewater at the same time by the same MFP. An algorithm has been developed for determining the signal components of a two-frequency thermal MFP, the ranges of which correspond to the ranges of changes in electrical resistivity k, relative permittivity εr, temperature t and density ρ of acidic, alkaline, and average brewery effluents. The basic relations that describe the two-frequency four-parameter electromagnetic method of joint measurements of the physicochemical parameters of acidic, alkaline and averaged beer effluents have been obtained.

10

Effect of Some Chemical Additives in Increasing the Electrical Conductivity of the Liquid Fuel Dimethyl Aminoethyl Azide (DMAZ)

Pakdehi Shahram G., Taffazolinia Hamidreza, Rezaei Sajjad, Fathollahi Manoochehr

Central European Journal of Energetic Materials

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2022

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Vol. 19, no. 3

265--280

EN

The novel liquid fuel 2-dimethylaminoethyl azide (DMAZ) is a good candidate for the replacement of the hydrazine family in space programs. However, it suffers from low electrical conductivity, which is dangerous during the production process and its transportation. A simple and effective way to increase its electrical conductivity is the use of antistatic additives. In this article, the electrical conductivity of DMAZ was initially predicted via an artificial neural network. Then, the increase in electrical conductivity of DMAZ was investigated using some chemical surfactants (such as hexylamine, octylamine and tributylamine), acetonitrile as a polar aprotic substance and a DMAZ salt (DMAZ·HCl) as an ionic liquid. Of these additives, acetonitrile had the greatest effect on the electrical conductivity of the fuel, exhibiting an increase in conductivity of about 45%. Adding a two-component mixture of acetonitrile and the DMAZ salt, further increased the electrical conductivity of the fuel by about 55%, relative to pure DMAZ. Tributylamine did not have a significant effect on the electrical conductivity of the fuel.

11

Study on the Microstructure, Electrical and Mechanical Properties of Hot Pressing Cr-50 Mass% Ni Alloys Fabricated by Addition of Various Ratios of Nanosized Ni Powders

Huang Jhong-Ren, Chang Shih-Hsien, Liao Cheng-Liang

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 3

955--961

EN

In this work, nanosized Ni (nNi) powders of 50 nm are mixed with Cr and Ni submicron-powders (600 nm) to fabricate Cr-50 mass% Ni alloys by vacuum hot pressing. In order to evaluate the influence of the nanosized Ni powders, different amounts of nanosized Ni powders are added to produce the Cr-(50-x) mass% Ni-x mass% nNi alloys (x = 0, 10, 20, and 30). The hot pressing was maintained at 1275°C, 48 MPa for 1 h. The microstructure evaluation, mechanical, and electrical properties were performed. The results reveal that mechanical and electrical properties are enhanced when increasing the nNi addition. The Cr-20 mass% Ni-30 mass% nNi presents the highest relative density of 96.53% and the electrical conductivity of 2.18×104 Scm-1, moreover, the hardness and transverse rupture strength values increase to 76.1 HRA and 1217 MPa, respectively. Moreover, a more homogeneous microstructure and a decrease in the mean grain size to 3.15 μm are acquired. Significantly, this fabrication procedure (adding 30 mass% nanosized nickel powders) results in the optimal microstructure, electrical and mechanical properties of submicron-structured Cr-(50-x) mass% Ni-x mass% nNi alloys.

12

Posadzki antyelektrostatyczne w obiektach przemysłowych

Ryżyński Władysław, Świątek-Żołyńska Sylwia

Materiały Budowlane

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2021

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nr 10

17--20

13

Bio-dielectric based on superconductors yttrium calcium barium copper oxide (YCaBa2Cu3O7−x) from eggshell as calcium oxide source via sol-gel process

Toumvong Wipawadee, Chitcharoentaweechoke Pornnita, Tangboriboon Nuchnapa

Materials Science Poland

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2021

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Vol. 39, No. 3

305--318

EN

Eggshell is a rich source of calcium that is a dielectric material used for doping in a superconductor. Yttrium calcium barium copper oxide (YxCa1−xBa2Cu3O7) was prepared using the sol-gel process and fired at 900 °C or 1,000 °C. The stoichiometric ratio of the raw materials Y2O3:BaCl2:CuO:CaO was 1:2:3:1 based on the molar mass. The obtained YCaBCO had an orthorhombic crystal structure composed of distorted oxygen-deficient perovskite. The orthorhombic structure was unsymmetrical, providing a substantial increase in the physical electromagnetic properties of the superconductor. The YBCO-900-reference analyzed using an impedance analyzer in the range from 500 Hz to (1 × 106) Hz and at room temperature (27 °C) had the following values for capacitance, electrical conductivity, and dielectric constant ± standard error: 8,286.70 ± 28.49 pF, (3.60 ± 0.01) × 107 S/m, and 1,874.794 ± 6.446, respectively. The YCaBCO-900-eggshell (YxCa1−xBa2Cu3O7) analyzed at 500 Hz at room temperature (27 °C) had high values for capacitance, electrical conductivity, and dielectric constant, namely, 8,540.10 ± 2.00 pF, (1.32 ± 0.00) × 108 S/m, and 1,988.540 ± 0.500, respectively. Furthermore, the YCaBCO-900-eggshell had electrical properties (capacitance, conductivity, and dielectric constant values) higher than those of YCaBCO-900-commercial grade measured under the same conditions. The YCaBCO-900-com grade had capacitance of 8,225.75 ± 0.73 pF, electrical conductivity of (1.40 ± 0.01) × 108 S/m, and dielectric constant of 1,874.59 ± 0.17, respectively. Therefore, eggshell is an alternative dielectric material useful for doping in yttrium barium copper oxide (YBCO) to form YCaBCO, thus causing an increase in its electrical properties. The obtained superconductor is a candidate that could be applied in many industries.

14

Impact of raw and purified wastewater reuse from the Dar El-Gueddari treatment plant on the soil

Njimat Smail, Elfettahi Fouad, Griou Hajar, El Brouzi Mohammed Y., Aboulouafa Mohammed, Ibn Ahmed Said

Journal of Water and Land Development

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2021

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no. 49

121--128

EN

The study has been carried out at two experimental sites. It aims to assess the impact of the reuse of raw wastewater, purified and diluted with conventional water on the physicochemical quality of soils compared to irrigated soils with conventional drilled water and non-irrigated soil. The obtained results show that the electrical conductivity EC and sodium gradually increase in all the plots irrigated with wastewater. Additionally, a slight increase in the pH levels at the first site and a slight decrease in the second site was seen, but at both sites the soils remained alkaline. The infiltration rate of water slide decreases in relation to the amount of irrigation, especially in plots irrigated by raw and treated wastewater. For the same plots, the values of organic matter increased, and the values obtained for the exchangeable sodium percentage (ESP) became high in the third year and reached 17.0% and 16.7% respectively.

15

Electrokinetic remediation technology of heavy metal contaminated soil based on improving soil electrical conductivity

Liu Jiangang, Zhang Wei, Liu Mingwei, Zhang Hao

Environment Protection Engineering

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2021

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Vol. 47, nr 4

5--17

EN

An electrokinetic remediation technique taking Cr(VI) as an example is proposed to improve the conductivity of contaminated soil, which significantly increases the current density in the soil. The improvement of soil conductivity was achieved by continuous spraying of NaCl solution with a concentration of 4 g·dm–3 on the soil surface. The distances of electrode pairs were 2.0 m and 1.5 m, respectively. The heavy metal-contaminated soil thickness was 25 cm, and the DC power supply voltage was 90 V. The experiment demonstrated that under the condition of continuous spraying of NaCl solution on the soil surface, the current density variation was related to the salt content in the soil, and the current density in the soil generally increased linearly with time. The effectiveness of soil remediation is related to the electric field strength and current density, and there exists an optimal electric field that can reduce the heavy metal content in the soil at any point by minimizing the electric field strength and current density. Most of the heavy metals can be concentrated within a diameter of about 15 cm around the anode under the optimal electric field, which can be remediated after removing the soil.

16

Spatiо-Temporal Study of the Ecological State of Water Bodies Located within the Detached Objects of the Urbanized Territory of Ukraine

Loboichenko Valentyna, Leonova Nataliia, Shevchenko Roman, Strelets Victor, Morozov Andriy, Pruskyi Andrii, Avramenko Oleksandr, Bondarenko Serhiy

Ecological Engineering & Environmental Technology

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2021

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Vol. 22, iss. 6

36--44

EN

The paper considers the impact of urbanized areas on the state of water bodies. The impact of various types of anthropogenic activities on water bodies located in cities was shown. In towns, there is worse water resource management than in large cities and the necessity of conducting more detailed research. Using the method of direct conductometry, a spatio-temporal study of the ecological state of water bodies located within the detached objects of the urbanized territory of the Ukraine was carried out using the example of Popasna town. It was shown that fluctuations in the electrical conductivity of these bodies are mainly due to the influence of surface runoff. It was found that in all studied ponds there was a significant drop in the electrical conductivity of water in March 2021, followed by an increase and stabilization in April and May 2021, the characteristic values of electrical conductivity range from 200 to 2900 μS, the relative standard deviation did not exceed 1.5%. The necessity of conducting further, more detailed study of the features of the influence of surface runoff on the water condition in the studied ponds was shown for the purpose of rational management of these water bodies.

17

Assessment of the Impact of Natural and Anthropogenic Factors on the State of Water Objects in Urbanized and Non-Urbanized Areas in Lozova District (Ukraine)

Loboichenko Valentyna, Leonova Nataliia, Shevchenko Roman, Kapustnik Anna, Yeremenko Serhii, Pruskyi Andrii

Ecological Engineering & Environmental Technology

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2021

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Vol. 22, iss. 2

59--66

EN

The paper analyzes the impact of urban areas on the state of water objects which are under the influence of these areas. Furthermore, the temporal regularities of the oscillations in electrical conductivity in a number of water objects in Lozova Town and Lozova District (Ukraine) were obtained using the method of conductometry. It was discovered that there was no significant anthropogenic impact on the studied water objects in Lozova Town and Lozova District of Kharkiv Region. The fluctuations in conductivity are mainly related to surface runoff. It was shown that the water in Lozova Town and Lozova District is characterized by electrical conductivity values in the range from 2000 μS to 3000 μS.

18

The Effect of Heat Treatment on the Microstructure Evolution and Properties of an Age-Hardened Cu-3Ti-2Mg Alloy

Liu Jituo, Wang Xianhui, Liu Jia, Ran Qianni

Archives of Metallurgy and Materials

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2021

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Vol. 66, iss. 1

163--170

EN

The study investigates the effect of heat treatment on the microstructure evolution and properties of an age-hardened Cu-3Ti-2Mg alloy. The precipitated Cu2Mg and β'-Cu4Ti phases consequently yield a depletion of the Cu matrix in regards to Ti and Mg solutes, which enhances the electrical conductivity. The Cu2Mg Laves phase and β'-Cu4Ti phase precipitates increase the hardness of the alloy due to the consistency and coherency of the later phase. However, the decrease of hardness is mainly associated with the coarse microstructures, that can be formed due to the phase transformation from metastable β'-Cu4Ti phase to more stable Cu3Ti phase. In the range of experiments, the optimum process is solution treatment at 700°C for 4 h, with subsequent age-hardening at 450°C for 4 h. The electrical conductivity, hardness, tensile strength, and elongation of the Cu-3Ti-2Mg alloy were 15.34 % IACS, 344 HV, 533 MPa, and 12%, respectively.

19

Właściwości elektryczne biowęgla pozyskiwanego metodą pirolizy z roślin energetycznych

Tomasik Marcin, Knaga Jarosław, Juliszewski Tadeusz, Lis Stanisław, Szul Tomasz

Przegląd Elektrotechniczny

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2020

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R. 96, nr 1

238--241

PL

Celem badań była analiza przewodności elektrycznej biowęgla uzyskanego z materiału organicznego metodą pyrolizy. W celu wykonania pomiarów właściwości elektrycznych biowęgla, zbudowano prototypowe urządzenie. Oprócz pomiarów właściwości elektrycznych umożliwia ono m.in. pomiar gęstości właściwej dowolnej próbki materiału sypkiego. W rozpatrywanym przypadku po napełnieniu komory roboczej i zagęszczeniu proszku otrzymywano pastylkę węglową. Dla niej określano pomiarami bezpośrednimi właściwości elektryczne tj.: spadek napięcia przy przepływie prądu przez próbkę (prąd stały i przemienny), oporność rezystora węglowego, wartość prądu przepływającego przez rezystor, indukcyjność oraz pojemność. Ponadto przy pomocy oscyloskopu rejestrowano charakterystyki dynamiczne napięcia w odniesieniu do prądu przemiennego przepływającego przez rezystor węglowy. Stwierdzono, że badanym próbkom można przypisać cechy obiektu elektronicznego o charakterze pojemnościowym.

XX

The aim of the research was to analyze the electrical conductivity of the obtained coal from organic material by pyrolysis. In order to take measurements of the electrical properties of the biochar, a prototype device was built. In addition to measurements of electrical properties, it enables measurement of the specific density of any sample of bulk material. In the case under consideration, after filling the working chamber and concentrating the powder, a carbon pellet was obtained. For it, direct electrical properties were determined by direct measurements, it is: voltage drop at the current flow through the sample (direct and alternating current), resistance of the carbon resistor, value of current flowing through the resistor, inductance and capacity. In addition, the dynamic characteristics of the voltage with respect to the alternating current flowing through the carbon resistor were recorded using the oscilloscope. It has been noted that capacitive features can be attributed to the test samples.

20

DC electrical conduction in strontium vanadium borate glasses

Banagar Arunkumar V., Kumar M. Prashant, Nagaraja N., Tipperudra Anand, Jakati Sangamesh

Materials Science Poland

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2020

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Vol. 38, No. 2

359--366

EN

A series of borate glasses with the composition x(SrO)∙(50 – x)V2O5∙0.5(B2O3) where x = 0, 0.1, 0.2, 0.3 and 0.4 were prepared by melt-quenching technique. The non-crystalline nature of the glasses has been established by XRD studies. Room temperature density and DC electrical conductivity of the samples were investigated in the temperature range of 300 K to 443 K. The molar volume and oxygen packing density (OPD) were estimated. The results show that the density, molar volume and OPD decrease with the increasing of SrO mole fraction. The DC electrical conductivity data has been analyzed in the light of Mott’s small polaron hopping (SPH) model and the activation energies were estimated. The conductivity was observed to rapidly fall and activation energy was found to increase when SrO was incorporated into the glass network. This may indicate that Sr+ ions have not contributed to the total conductivity and the observed conductivity may be of polaronic type only, which is due to the hopping of electrons between multivalent states of vanadium. Various small polaron hopping parameters such as small polaron radius, rp, effective dielectric constant, ϵp, polaron band width, J, optical phonon frequency, ʋo, small polaron coupling constant, ϒp, density of states at Fermi level, N(EF) were estimated and discussed.