All Articles

Summary: This article is devoted to the extraction of silver (Ag) ions in an acidic medium at pH 5 by a copolymer of maleic anhydride with styrene (MASC), chemically modified with 4-nitroaniline-2-arsonic acid (NAA). The structure of the sorbent CSMA-4-nitroaniline-2-arsonic acid was studied by IR spectroscopy methods. The study of Ag(I) ion sorption was carried out under static conditions. The influence of various parameters on the process of Ag(I) ion sorption was studied. Maximum sorption of metal ions is observed at pH 5. The sorption equilibrium was established after 3 hours. As the concentration of sorbed metal ion increases, it reaches its maximum at 6·10-3 M. To study desorption, the effect of different acids - HNO3, CH3COOH with the same concentrations on the desorption of Ag(I) from the sorbent was studied. The experiment showed that the maximum desorption of Ag(I) occurs in 2 M nitric acid (HNO3).

Summary: Oil products are the strongest toxic substances on the earth's surface, and their permissible levels in water bodies are 0.1 mg/dm3. However, until now, insufficient attention has been paid to determining the amount of oil products in natural and waste water. The article presents the results of spectrophotometric determination of the amount of oil products in water samples taken from lakes in the Absheron Peninsula and compares them with the existing gravimetric method. Extractants were selected to determine oil products, and the improved spectrophotometric method was applied to real objects under optimized conditions. The aim of this work was to select an organic extractant for the extraction of petroleum products from natural and waste waters and to apply an improved spectrophotometric method to natural objects. The aim of this work was to select an organic extractant for the extraction of petroleum products from natural and waste waters and to apply an improved spectrophotometric method to natural objects. The waters taken from the lakes of Gu and Girmizy on the territory of the Absheron Peninsula were selected as objects of the study. Spectrophotometric, gravimetric and chromatographic methods of analysis were used in the study. A mixture of organic reagents was selected to determine oil products in the waters of the lakes. Using the selected organic reagent, the oil products contained in the objects of study were isolated and analyzed using the GX-MS method. A new improved separation method using a mixture of organic reagents was proposed for the spectrophotometric determination of oil products. An improved spectrophotometric method for determining oil products in natural waters was developed. Optimal conditions for the extraction of oil products were found and the extraction method using a new organic reagent was optimized. The proposed method was tested on natural waters.

Summary: The waterflooding technique is one of the most widely used and efficient technique for increasing oil recovery. In an oil-wet reservoir, however, the higher the water mobility, the lower the oil production. The following research will look into the effects of high and low saline waterfloods on oil recovery and water mobility with application of magnetic field. This research also looks at how varied water salinity injections affect wettability and salt production rates. The design of a three-dimensional, two-phase model, i.e., water and oil, is the first step in this research. Initially, the reservoir is oil-wet. To show the wettability change, relative permeability curves are generated during simulation. The impact of salinity on oil production, water mobility, and salt production is examined by a comparison of high and low saline waterfloods. In order to identify an effective well injection technique, a sensitivity analysis was done for two possible injections well patterns: five spot and direct line drive. The recovery attained by lowering the salinity of the water was found to be around 80%, with a cumulative oil production of 0.45 MMSTB. The water cut is prolonged to a large extent by lowering the salinity of the water.

Summary: In the research work, diethylamine, dipropylamine, dibutylamine complexes of the mixture of alkylarylsulfonic acids obtained on the basis of the light gas oil fraction obtained from the secondary oil refining process - the catalytic cracking process were synthesized, solutions of the samples were prepared in water, water + ethyl alcohol, water + isopropyl alcohol. Some physico-chemical properties of the samples were studied, bactericidal properties were studied by keeping them in a thermostat at a temperature of 32ºC for 15 days and calculating the amount of H2S produced at the end. It was determined that the aqueous solution of the diethylamine complex of the mixture of alkylarylsulfonic acids showed a high bactericidal effect (99%) at the concentration of 50 mg/l. Solutions of diethylamine and dipropylamine complexes in water at the concentration of 75 mg/l showed 100% bactericidal effect and reduced the number of bacteria to zero. Solutions of dibutylamine complex in water + ethyl alcohol, water + isopropyl alcohol at the relatively high concentration (150 mg/l) showed 100% bactericidal effect and stopped the life activity of bacteria.

Summary: As it is known, the recycled steel smelting industry is considered as one of the economically and ecologically very important fields. In this industry, the repro-cessing of obsolete steel waste, which is dangerous for the environment, is of great economic importance as well as environmentally beneficial. the processes of ore extraction and its subsequent stages of processing save on the use of natural resources. steel smelting is important. During the research carried out by us, it was determined that a large amount of water is also used in the recycling processes of out-of-service steel technological equipment in the recycled steel smelting industry. The object of the study was the Baku Steel Smelting Enter-prise. For the first time, in-depth environmental analyzes of the composition of the industrial streams-wastewater received during the technological process of that production were carried out by us. It was determined by us the emissions of ecotoxicant substances - H2S, SO2, NH3, SO3, NO2 Cl2, HCl, HCN, PH3 which are contained in the industrial streams formed in the main production areas of that enterprise and evaporate in a short period of time.

Summary: This study investigates the thermochemical luminescence (TCL) behavior of heavy residues derived from Karabakh, Absheron, and Naftalan crude oils to examine their chemical transformations and implications for quality. Crude oil is a complex mixture of hydrocarbons, dissolved gases, water, salts, and impurities, with its composition varying significantly. Advanced spectroscopic techniques, including UV, NMR, IR, and luminescence analysis, were utilized to explore the structural-group composition and physicochemical properties of these oils. TCL analysis revealed consistent characteristics among the heavy oil residues, marked by hybrid molecular structures and weakly bonded C–H linkages. The residues, after undergoing de-resinification and deasphalting, exhibited a notable uniformity, making them promising candidates for use as biologically active substances. Photoirradiation experiments demonstrated that the TCL maxima for heavy residues appear in lower-temperature spectral regions compared to many distillate fractions. The visible light emission was attributed to the decomposition of endoperoxides during the recombination of peroxide radicals. This observation opens the possibility of utilizing hydrocarbons as alternative light sources, including applications involving solar energy. These results have implications for improving refining processes, optimizing the transportation and storage of crude oil, and broadening the industrial applications of petroleum and its by-products.

Summary: In this study, we delve into the spectral properties of a pencil of nonself-adjoint second-order differential operators characterized by almost periodic potentials and impulse conditions. Such operators arise in various physical models, particularly in quantum mechanics, where they describe systems with discontinuities in their potentials or boundary conditions. Understanding the spectrum of these operators is crucial for comprehending the stability and dynamics of the associated physical systems. By investigating the spectral gaps and accumulation points we aim to contribute to the broader understanding of non-self-adjoint operator theory and its applications in mathematical physics.

Summary: In this paper, a model of single server queueing-inventory system (QIS) with Markovian Arrival Process (MAP) and phase-type distribution (PH-distribution) of the service time of consumer customers (????-customers) is considered. After completing the service of ????-customer, he (she) can make one of the following decisions: (1) eventually leave the system with probability (w.p.) ????ℓ; (2) after a random “thinking” time returns the purchased item w.p. ????????; (3) after a random “thinking” he (she) feedback to buy a new item w.p. ???????? . It is assumed that ????ℓ+????????+???????? = 1. If upon arrival of the ????-customer the system main warehouse (SMW) is empty, then the incoming customer, according to the Bernoulli scheme, is either joins the infinite queue or leaves the system. A virtual finite orbit can be considered as a waiting room for feedback customers (????-customers). Returned items are considered new and are sent directly to SMW if there is at least one free space; otherwise, this item is sent to a special warehouse for returned items (WRI). After completing the service of each customer, one item is instantly sent from the WRI (if any) to the SMW. In SMW, the (????, ????) replenishment policy is used and it is assumed that the lead time follows exponential distribution with finite parameter. When the stock level reaches its maximum value due to items returns, the system immediately cancels the regular order. Along with classical performance measures of QIS new specific measures are defined and numerical method for their calculation as well as maximization of the revenue function are developed. Results of numerical examples to illustrate the effect of different parameters on the system’s performance measures are provided and analyzed. We also provide a detailed analysis of an important special case of the Poisson process/exponential service time model.

Summary: Public interest concerning the environmental progress of economies has been developing across societies and countries. Such awareness requires dealing with energy, environment, and economic sides altogether. By considering this reality, this research investigates that how there is an effect of environmental policy stringency (EPS), energy transition index (ETI), and income (gross domestic product, GDP) on CO2 emissions. In doing so, the research analyzes BRICS countries, which are leading developing countries causing high emissions and consuming large amounts of energy, uses data between 2000/Q1 and 2020/Q4, and uses wavelet local multiple correlation approach to analyzes the nexus across times and frequencies. The results demonstrate that (i) EPS declines CO2 emissions in Brazil at low and high frequencies; (ii) GDP curbs CO2 emissions in India at high frequencies; (iii) across remaining times and frequencies, EPS, ETI, and GDP have a mixed effect in BRICS countries; (iv) based on four-variate cases, EPS, ETI, and GDP have an increasing combined effect on CO2 emissions across all times, frequencies, and countries; (v) the most dominant factor differs according to frequencies and countries, where ETI is mainly leading in Brazil, Russia, and India, EPS is pioneering in South Africa, and China has a mixed situation. Thus, the research empirically proves the diverging effects of EPS, ETI, and GDP on CO2 emissions across times, frequencies, and countries.

Summary: Invisible watermarking has become a vital technique in digital image security, allowing hidden data to be embedded without affecting visual quality. This study addresses the challenge of maintaining watermark imperceptibility while resisting common image distortions. The goal of this research is to assess the effectiveness of a hybrid watermarking method that combines Discrete Cosine Transform (DCT) and Discrete Wavelet Transform (DWT). In the proposed approach, the watermark is embedded in the DCT coefficients of the low-frequ-ency DWT sub-band. Experiments were conducted in both RGB and YCbCr color spaces, with varying strength factors (alpha). The method demonstrated high imperceptibility, with SSIM values above 0.998, but limited robustness against JPEG compression, Gaussian blur, and noise. These findings highlight the need for more resilient hybrid methods