Himia, Fizika ta Tehnologia Poverhni

Lightweight concrete is a building material with a density not exceeding 2000 kg/m3. Its structure is determined by the structure of the used components and manufacturing methods. The advantages of these building materials are their low density, good thermal insulation, frost resistance, high thermal resistance, ease of use of blocks, which is due to their large size and low weight; also important is their wide range, which allows one to choose the optimal material composition suitable for operating conditions. In the production of lightweight concrete, pumice, along with binders, is one of the main components of its composition. These minerals are frothy, have a low volumetric weight, high porosity and high toughness. All these properties make them a valuable mineral raw material mainly used as additives for lightweight concretes and hydraulic cements. Pumice is abundant in Georgia (more than 35 million m3). The prospects for the use of these minerals are great, so the study of their physical and chemical properties is relevant and obligatory. Six pumice samples from four different locations in the Javakheti region of Georgia were studied. Chemical, X-ray diffractometric, infrared spectroscopic, petrographic, and granulometric methods were used for investigations. Chemical and mineralogical composition of the analyzed samples, peculiarities of their structure, as well as bulk and compacted samples volume masses and their granulometric composition were determined. The slags with the best properties will be recommended as additives for use in the production of lightweight concrete.

G. P. Tsintskaladze

T. N. Kordzakhia

T. V. Sharashenidze

M. G. Zautashvili

G. M. Beridze

V. M. Gabunia

I. R. Javakhishvili

Himia Fizika ta Tehnologia Poverhni

Prospects for the use of pumice from Georgia in lightweight concretes

格鲁吉亚浮石在轻质混凝土中应用的前景

This work is aimed at studying the influence of kinetic parameters and diffusion coefficients on stationary concentration distribution of electroactive and electroinactive species in a model electrochemical process with a preceding chemical reaction under constant current. We consider a preceding homogeneous first-order chemical reaction with a reversible heterogeneous electrochemical reaction at a planar electrode surface. To elucidate the peculiarities of stationary concentration distribution of electroactive and electroinactive species in a thin stagnant layer attached to a planar electrode surface, the exact solutions of a system of differential equations describing the variations of the concentrations of the participating species with a distance to electrode surface have been analyzed. The cases of equal and unequal diffusion coefficients of species involved in a preceding chemical reaction have been considered. It has been shown that the diffusion coefficients of both reacting species can affect their concentration profiles in a thin stagnant layer attached to electrode surface. The calculations demonstrate that the stationary concentration of electroactive and electroinactive species decreases with an increase of the diffusion coefficients. The influence of the rate constants of a preceding chemical reaction on the stationary concentration is different for electroactive species and electroinactive one. As the rate constants of a preceding chemical reaction are increased, the stationary concentration of electroactive species decreases, whereas the stationary concentration of electroinactive species increases slightly. This is also valid for the case of the stationary surface concentration of electroactive and electroinactive species. The thickness of a thin stagnant layer attached to a planar electrode surface where a change of the concentration of electroactive species takes place, also affects the stationary concentration distributions. The effect of this parameter is especially crucial at low values of a preceding chemical reaction rate constants.

O. I. Gichan

Influence of kinetic parameters and diffusion coefficients on stationary concentration of electroactive and electroinactive species in a model electrochemical process with a preceding chemical reaction

动力学参数和扩散系数对具有前置化学反应的电化学过程中电活性与非电活性物种稳态浓度的影响

The purpose of this study was to determine the effect of carbon nanotubes (CNTs) on the thermal decomposition and thermo-oxidative destruction of nanocomposites based on polyester resin with a content of 0.1, 0.3 and 0.5 % by weight of CNT as characteristics of their heat resistance. Determination of thermal decomposition products, activation energy of their desorption, total amount of volatile decomposition products of composites was determined by the method of thermoprogrammed desorption mass spectrometry (TPDMS). Using derivatography methods (Q 1500D), patterns of thermo-oxidative destruction of polymer composites were investigated. It is shown that the addition of 0.1 wt. % CNT in the resin shifts the temperatures of the maximum thermograms (Tm) to higher values, increases the activation energy of desorption of all fragments of destruction products in the range m/z 18–104, compared to the original resin, i.e. this indicates an increase in the thermal stability of this composite. Increasing the CNT content to 0.3, 0.5 % by weight shifts Tm towards lower values, significantly reduces the activation energy of desorption for almost all polymer fragments. If at a content of 0.1 wt. %, CNTs in the polymer matrix are structurally “ordered” according to possible mechanisms, then an increase in the content of CNTs, on the contrary, leads to a reversible effect, due to the relatively large content of CNTs, their insufficient deagglomeration and uneven distribution. Thermo-oxidative degradation of unfilled resin has two characteristic minima at T = 383 °C and 439 °C (endothermic reactions of thermo-oxidative decomposition). The addition of CNTs in the amount of 0.1, 0.3, 0.5 wt. % shifts the temperatures towards higher values. Samples melt up to 385 °C followed by combustion with maximum temperatures at 443 and 534 °C. Probably, the presence of the second peak (534 °С) indicates the possibility of the formation of a certain percentage of a more ordered phase in the polymer. Thermooxidative decomposition of composites is characterized by an increase in the initial temperatures of phase transitions. This is probably due to the presence of a carbon nanofiller in the polymer matrix, which increases the heat capacity and thermal conductivity of the composite, possibly initiating crosslinking centers of free (unbound) polymer chains, which, in turn, causes a decrease in kinetic mobility in the polymer.

N. V. Siharova

Yu. I. Sementsov

S. V. Zhuravsky

M. V. Borysenko

D. L. Starokadomsky

K. A. Yurieva

A. D. Terets

O. V. Mistchanchuk

P. Pączkowski

B. Gawdzik

Thermal destruction and thermophysical properties of polymer composites based on polyester resin with different content of carbon nanotubes

聚酯树脂基聚合物复合材料的热破坏与热物理性能：不同碳纳米管含量的影响

The electron transport layer (ETL) material plays a crucial role in determining the device efficiency and stability of organic solar cells (OSCs). Tin oxide (SnO2) semiconductor is commonly used as ETL in organic solar cells and recently has attracted significant attention. In this paper SnO2 particles deposited by pulsed laser deposition (PLD) are used as ETL layer in inverted organic solar cells with structure (FTO/SnO2/PTB7-Th:O-IDTBR/ MoO3/Ag). The characterizations of cell using the Ossila Solar Cell I-V Test System have been investigated as well as the structural properties of SnO2 thin film using a Field emission scanning electron microscope (FESEM), The atomic force microscopy (AFM) and X-ray spectrum have been also investigated. It has been found that the Power conversion efficiency (PCE) of solar cell is 15.08 %. The stability was measured for 30 min with continuous illumination under the ambient air conditions, it was decreasing gradually over the illumination period to about half initial value of efficiency. The FESEM images and XRD spectrum show that the films were crystalline. The XRD spectrum shows the presence of several peaks belonging to SnO2 nanoparticles. The optical properties of SnO2 film indicate the increase in the transmittance and refractive index spectrum, while the absorbance spectrum decreases, the maximum absorbance was observed at 320 nm wavelength and the optical energy gap record about 3.1 eV and the grain size for SnO2 reported around 20–60 nm

Faris M.A. Al-Hamdany

Abdulkhaliq A. Sulaiman

Abdullah I.M. Alabdullah

Study of the performance of organic solar cells using SnO2 nanoparticles as electron transport layer growth by pulsed laser deposition

利用脉冲激光沉积法制备SnO2纳米颗粒作为电子传输层的有机太阳能电池性能研究

A new universal gas-chromatographic method of identification of toxic impurities is proposed in order to improve the quality indicators of alcoholic beverages. Application of chromatographic methods in wine making is characterized by some peculiarities, which is stipulated from one hand by substance characteristics as they are and from the other by changes in chromatographic methods possibilities. The method allows to determine the quality and chemical composition of the alcoholic beverages, which to some extent determines the possibility of regulating its quality on a scientific basis. Modification of the methods presented in the work is based on utilization of packed and capillary-packed columns. They are mainly usable for quantitative analysis, are stable, characterized with good reproducibility and can be used as long as a year and more. Several immobile liquid phases – PEG-300, PEG-400, PEG-20000, SE-30 and polymeric sorbent – Poropak-Q, Separon-CDA – were tested in order to determine the optimum conditions for chromatographic separation. To achieve this goal, a combined chromatographic packed column (Poropak-Q+SE-30) based on the principles of adsorption and distribution chromatography was created. Chromatography of a twelve-component 0.1 % graded mixture (acetone, acetic aldehyde, butanone-2, methanol, propanol-2, ethanol, butanol-2, propanol-1, isobutanol, butanol-1, crotonaldehyde, isopentanol) was carried out. The analyses were performed in both isothermal and temperature-programmed modes. The chromatographic method developed by combining air-adsorption and distribution chromatography (combined column) provides the possibility of effective identification and maximum separation of harmful micro-impurities in alcoholic beverages.

L. G. Eprikashvili

N. V. Pirtskhalava

M. A. Dzagania

A. G. Rakviashvili

New sorbents for determining the quality of alcoholic beverages by chromatographic analysis

用于通过色谱分析确定酒精饮料质量的新型吸附剂

Publication Information	Publisher: Chuiko Institute of Surface Chemistry of National Academy of Sciences of Ukraine，Publishing cycle: ，Journal Type: journal，Open Access Journals: No
Basic data	Year of publication: 2019，Proportion of original research papers: ，Self Citation Rate:， Gold OA Rate:

Himia, Fizika ta Tehnologia Poverhni

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Prospects for the use of pumice from Georgia in lightweight concretes

Influence of kinetic parameters and diffusion coefficients on stationary concentration of electroactive and electroinactive species in a model electrochemical process with a preceding chemical reaction

Thermal destruction and thermophysical properties of polymer composites based on polyester resin with different content of carbon nanotubes

Study of the performance of organic solar cells using SnO2 nanoparticles as electron transport layer growth by pulsed laser deposition

New sorbents for determining the quality of alcoholic beverages by chromatographic analysis

Prospects for the use of pumice from Georgia in lightweight concretes

Influence of kinetic parameters and diffusion coefficients on stationary concentration of electroactive and electroinactive species in a model electrochemical process with a preceding chemical reaction

Thermal destruction and thermophysical properties of polymer composites based on polyester resin with different content of carbon nanotubes

Study of the performance of organic solar cells using SnO2 nanoparticles as electron transport layer growth by pulsed laser deposition

New sorbents for determining the quality of alcoholic beverages by chromatographic analysis

ISSN	2079-1704, 2518-1238
h-index	6