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September 2024
Table of Contents
| Comparison of the Electron Donor-Acceptor and Sensing Capacity of The Selected CNTs in Drug Delivery Applications |
| Serap Senturk Dalgic, Fatma Kandemirli |
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Abstract: Carbon nanotubes (CNT) have remarkable properties in drug delivery applications. Here, the size, shape, and functionalization effect on the electron-donor acceptor and sensing capability of the selected CNTs for drug delivery applications have been investigated using density functional theory (DFT). The anti-oxidative activity and toxicity have been calculated using quantum molecular / Frontier Molecular Orbital (FMO) parameters. The electrophile (w) values vary according to CNTs and the groups of drugs interacting with CNT. The electro-donating and electro-accepting powers have been computed based on the electron affinity and the ionization potential parameters. Therefore, the size, doping effect and electron-donor-acceptor MAP (DAM) of the studied CNTs have been thoroughly discussed. These findings define the system, paving the way for promising sensors in practical applications. These CNT sensors can be used to detect, recognize, and carry drugs for their medicinal applications, underscoring the relevance and importance of our research. Keywords: Carbon nanotubes, Computational materials science, Materials science and technology, Nanotechnology, Nano sensors |
| DOI: 10.47978/TUS.2024.74.03.001 |
| Manganese Doping Effect on the Sensing and Electronic Properties of Selected Carbon Fullerenes: a DFT Study |
| Seyfettin Dalgic |
Abstract: In this study, the electronic properties of the different types of undoped Carbon Fullerenes (Cn) and Mn atom doped fullerene (MnCn-1) nanostructures have been investigated by density functional theory (DFT). The carbon fullerene isomers between C20 and C40 were selected. The sensing and electronic properties of selected fullerene structures were calculated based on the highest occupied molecular orbital energy (EHOMO) and the lowest unoccupied molecular orbital energy (ELUMO), energy gap (Eg) and work function (Φ) values. The density of states (DOS) were generated for frontier molecular orbital (FMO) analysis. The sensing mechanism of carbon fullerenes has been determined by calculating the band gap and work function variation, %ΔEg and %ΔΦ, during the Mn atom dopping. This study will give an idea about these materials for drug delivery and sensing applications. Keywords: Carbon Fullerene, Mn doped carbon fullerene, DFT |
| DOI: 10.47978/TUS.2024.74.03.002 |
| About Characteristics of the Induction Motor |
| Kremena Y. Dimitrova, Yuri K. Zhelyazkov, Ivan D. Torlakov |
Abstract: The aim of this paper is to study the basic characteristics and dependencies of an induction motor. The shaft speed and torque are studied under variation of voltage, frequency and current supplied to the stator windings of an induction motor with short-circuited rotor. The voltage and current of the induction motor were varied by switching from star to delta circuit and the frequency was varied using a three-phase frequency converter. Keywords: Induction motor, revolutions, shaft torque, frequency converter |
| DOI: 10.47978/TUS.2024.74.03.003 |
| Implementation of an Automated Emissions Monitoring System at the Enterprise |
| Symbat Satybaldy, Dinara Baskanbayeva, Nikolay Petrov |
Abstract: The automated emissions monitoring system is designed for continuous automatic measurement of mass (or volume) concentrations of pollutants, flow rate, temperature and humidity of gas-air mixtures discharged through stationary organized emission sources. The ASKPV functionality ensures the creation of a primary database, statistical processing and visualization of information, and calculation of emission power (g/s). Keywords: Monitoring, emissions, analysis, methods, risk assessment |
| DOI: 10.47978/TUS.2024.74.03.004 |
| Influence of Heat Flux Density on Combustion Efficiency in the Initial Torch Section |
| Neven Krystev, Ivan Petrov |
Abstract: Proper understanding of combustion and heat transfer in combustion devices, and clarification of combustion and thermal efficiency, requires accurate measurement of heat flux density. In the present work, the influence of heat flux density on the combustion process in the initial section of the flare, under separate fuel and oxidant feed in the injected swirl conditions, is investigated using computer simulation. The possibility of determining the basic parameters of the combustion process and its control is shown. Basic characteristics of the heat transfer between the burning flare and the boundary surfaces of the combustion chamber are investigated, including heat transfer by both radiation and convection. The effect of changing the heat flux density through the cylindrical surface of the combustion chamber is analysed for four cases - under adiabatic conditions and in the presence of heat transfer, using Ansys/CFX software. It presents the possibilities of achieving optimal results in combustion processes by changing the geometrical, initial, boundary conditions of the combustion model. Keywords: Harmful emissions, combustion processes, gaseous fuel, heat flux density, numerical simulation |
| DOI: 10.47978/TUS.2024.74.03.005 |
| Forecasting the Generation of Electricity from a Hybrid System |
| Evgeniya Petkova Vasileva, Ivelina Filcheva Takeva-Beberova |
Abstract: The article predicts the generation of electricity from a wind-photovoltaic system (hybrid system) to supply a consumer. The geographical location of the user is a remote and hard-to-reach area, which is a reason to build an electricity transmission network. The designed hybrid system is modeled in a Matlab Simulink environment, which proves the generation of the required power according to the known load schedule for a period of one year. Keywords: Hybrid system, photovoltaic modules, wind turbine, performance, load schedule |
| DOI: 10.47978/TUS.2024.74.03.006 |
| Analyzing of Critical Points of Corporate Network for Upgrading Its Scalability |
| N. Dimov, D. Nyagolov, R. Krystev |
Abstract: Networking technologies have evolved significantly over the years as Ethernet and Wi-Fi requirements have increased significantly. In addition to supporting a range of devices, LANs require managing traffic generated from many other sources such as live streaming video, video surveillance, network attached storage (NAS), voice over IP (VoIP), virtualization, cloud and IoT devices and services generate demand for additional bandwidth and low latency. It is clear that legacy network equipment and cabling is not ready to handle the increased data traffic, creating the need for research and analysis to build an efficient and low-cost solution. In this study, the main problems encountered in the specific enterprise LAN are discussed and analyzed. Keywords: Network, bandwidth, latency, performance. |
| DOI: 10.47978/TUS.2024.74.03.007 |
| On the Solvability of a Two-Point Third-Order Boundary Value Problem Under Barrier Strips |
| G. Mihaylova, P. Kelevedjiev |
Abstract: We study the solvability of a two-point boundary value problem for nonlinear third-order ordinary differential equation. To prove the established existence results, we use a well-known global solvability theorem obtained by a topological method which means that the problem for the solvability of the considered boundary value problem is replaced by the problem for the existence of a fixed point of a suitable introduced operator. The application of the global theorem requires a priori bounds. These are obtained using the barrier strips technique. A result guaranteeing positive or non-negative, concave solutions is given also. The existence results are illustrated by an example. Keywords: Third-order differential equations, boundary value problem, existence, barrier strips |
| DOI: 10.47978/TUS.2024.74.03.008 |
| Robust Stability of Sets For Uncertain Impulsive Gene Regulatory Networks |
| G. Stamov, M. Kostadinova - Gocheva |
Abstract: This article extends methods of stability analysis for discontinuous impulsive gene regulatory networks (IGRNs). Main results: for the model, uniform global robust exponential stability and uniform robust global asymptotic stability are related to sets. The main methods of investigation are the comparison principle and Lyapunov-like impulsive functions. Keywords: Gene Regulatory Networks, Impulses, Robust stability of Sets |
| DOI: 10.47978/TUS.2024.74.03.009 |
| Ability to Study the Velocity Profile of a Composite Isothermal Jet |
| Koycho Atanasov, Ivan Ivanov |
Abstract: The case of interacting jets or the interaction of a jet with a solid surface finds extensive application in practice. Various applications are realized in air conditioning, ventilation, combustion technology and others. In combustion engineering investigations, the research is conducted under isothermal conditions (without combustion) as a starting point. Obtaining a detailed picture of the velocity profile under isothermal conditions of a jet is a necessary prerequisite for research under combustion conditions. In the literature there are many studies of combustion processes implemented under different design geometries. One part of these solutions are implementations of more than one combustion device whose torches interact to form a composite combustion torch with useful properties for practice. From the study of the velocity profiles, the presence of circulation zones relevant to the quality of the combustion process can be supposed. The main factor observed in such studies is the geometric shape of the composite jet that is produced. Keywords: velocity profile, composite isothermal jet, injection nozzle, injection burner |
| DOI: 10.47978/TUS.2024.74.03.010 |
| On the Solvability of a Fourth-Order Initial Value Problem Under Barrier Strips Conditions |
| Todor Todorov, Petio Kelevedjiev |
Abstract: This article is devoted to the existence of global solutions of the initial value problem for fourth-order nonlinear ordinary differential equation. To prove the established existence results we use a global existence theorem obtained in our previous work by a topological method, that is, the problem for the solvability of the considered initial value problem is replaced by the problem for the existence of a fixed point of a suitable introduced operator, the existence of a fixed point follows from the topological transversality theorem. The application of the global existence theorem needs a priori bounds which follow from imposed barrier strips conditions. In addition to an existence result, a result guaranteeing the existence of at least one positive, increasing (non-negative, non-decreasing), convex solution is also obtained. Keywords: barrier strips, existence, fourth-order differential equations, initial value problem |
| DOI: 10.47978/TUS.2024.74.03.011 |
| The Interactive Carpet Made of Textile Materials as an Innovative Educational Tool in Kindergarten |
| Margaret Sivova, Tanya Peneva, Vasil Ganev |
Abstract: Interactive technologies are increasingly entering the educational process, offering new opportunities for learning through play. The interactive textile carpet is one of these innovative means that combines tactile and visual stimuli with educational game methods. The report examines the possibility of including the didactic tool "interactive carpet" in the learning process for preschool children, indicating the positive effects on their cognitive, physical, emotional, social, language and communication development. A classification of children's interactive 3D carpets based on a set of criteria is proposed. Popular commercial brands and individual entrepreneurs, positioned in the market of children's products and offering educational rugs in their assortment, were examined. Keywords: Interactive carpet, preschool, game, learning process |
| DOI: 10.47978/TUS.2024.74.03.012 |
| Construction Features of Single-Seamed Sleeves for Women's Outerwear |
| Hristo Petrov |
Abstract: The form and elements of internal development of women's outerwear are directly dependent on the style in fashion, the purpose and the season. Basic constructions are dimensioned with proportions between component lines and allowances for freedom relating to the straight, fitted or semi-fitted silhouette. By applying modeling principles, corresponding model variants are obtained from these constructions. In women's outerwear, sleeves can be both single-stitched and multi-stitched. Multi-stitched sleeves can be constructed in an assembly pattern similar to a women's jacket sleeve, or by splitting the unfolded single-stitched sleeve. Their constructive shaping may be accompanied by a preliminary deepening of the sleeve curve, or by transforming the shoulder folds of the two main details. The second option is considered here, when the shoulder flexion on the back is completely closed, and that on the front - partially. The research and suggestions made do not concern the constructions of the back and the front part, but affect the geometric construction of the sleeve, some of its model variants and the placement of technological matching centers. Keywords: women's outerwear, single-stitched sleeve, size, basic construction, sleeve oval |
| DOI: 10.47978/TUS.2024.74.03.013 |
| Analysis of The Possibilities for Reducing Water Vapor Consumption in Oil Refineries by Improving the Condensate Separation System |
| Konstantin Kostov, Ivan Denev, Dimitar Dinkov |
Abstract: It is known that in oil refineries, water vapor is the most used heat carrier, which is transported to consumers through a steam transmission network and occupies a significant share in their energy balance. From this point of view, any organizational or technical measure leading to a reduction in steam consumption can be considered an economic and energy-efficient solution. Of significant interest is the consumption of steam, because there is the greatest potential for the implementation of energy-saving measures. The required steam parameters for each specific installation are different, but the main reason for using this technology is that refineries have one main source of thermal energy that must supply steam to consumers. The article discusses and analyses the factors related to the possibility of reducing water vapor consumption in oil refineries by improving the condensate separation system. The technical feasibility and economic expediency of the replacement of old and the integration of new energy-saving technological units from the steam-condensation plant of an oil refinery have been assessed. The goal is to achieve a reduced consumption of steam for energy, technological and auxiliary purposes, which are a prerequisite for realizing energy savings and reducing energy costs. The scientific novelty is demonstrated through the proposal of new ways of organizing the work of the steam-condensation economy, with the aim of achieving cleaner production and achieving high energy efficiency of the considered oil refinery. Keywords: Condensate separation system, oil refinery, reducing water vapor consumption, energy saving measures |
DOI: 10.47978/TUS.2024.74.03.014 |
| Exploring the Range of Felt Products Used in the Fashion Industry |
| Tanya Peneva, Margaret Sivova |
Abstract: Wool felting is a technique for creating non-woven surface textiles, known for millennia, which fully complies with the strategy of the European Union, regarding the sustainable development of the textile and fashion industry. In this article, various plaiting techniques and their artistic shaping are presented. The range of felt products offered on the world market has been studied. The results of the research will find application in optimizing the assortment of manufacturers, reducing losses from unrealized production and increasing the sustainability of the fashion industry. Keywords: Felting, sustainable development, fashion industry |
DOI: 10.47978/TUS.2024.74.03.015 |
| Interpretation of the Bulgarian National Costume in the Collections of Native Designers and Fashion Brands |
| Tanyo Hristov, Margaret Sivova |
Abstract: The report presents a survey among Bulgarian designers, fashion brands and trademarks creating national style clothing. The selection was made according to the following groups of criteria: First group – conceptual - imagery component, which reflects what idea and essence are embedded in the philosophy and positioning of the brand; The second group - means of expression used in the design of garments, namely: shape and silhouette of the products; proportions; colour design; construction solutions; type and structure of the textile materials used; type of ornamentation; consumer segment. The significance of the brand and its role in forming national consciousness, preserving and promoting the sustainable elements of the Bulgarian national costume are described. Keywords: Fashion brand, fashion design, fashion collection, Bulgarian national costume |
DOI: 10.47978/TUS.2024.74.03.016 |
| Basic Techniques in the Creation of Felt Non-Woven Textile Material Regarding Wool Structure and Properties |
| Nikolay Tranchev, Margaret Sivova, Tanya Peneva |
Abstract: The article examines the structural characteristics of wool fiber, its properties, and types of wool. Different technologies for the production of non-woven textile material by the method of wool felting are analyzed. The process of making a decorative panel using the "wet felting" technique is described in detail. The main stages, necessary materials, and manipulations to obtain the finished canvas are indicated. Keywords: Wool, felt, wet felting, non-woven fabrics, felt products |
DOI: 10.47978/TUS.2024.74.03.017 |
| Effect of Ink Layers on Inkjet Printing Quality |
| Georgi Georgiev |
Abstract: This paper will discuss research concerning the influence of the number of ink layers deposited by ink jet for textile printing. With the aim to establish the optimal number of layers as to achieve good quality prints, it discusses the good colorfastness during longer time period and exposure to different environmental factors including temperature, light etc. Three typical materials with the same raw material compositions, but different fabric weight and thread count were chosen and printed with digital ink jet technology. Materials were printed with variations in the ink layers number and the correlation between K/S factor and number of applied ink layers was determined after the printing process. Upon finished printing process, the samples were treated with heat, light and other simulated environmental influences in line with the appropriate international standards. The changes were detected by common visual ranking methods (gray scale and blue wool reference scale) as well the spectrophotometric measurements for obtaining spectral data of the colorfastness and staining, what was followed by additional testing of the heating element with thermo vision camera. Microscopic view of the changes on the printed surfaces upon exposing them to different simulated factors was obtained by SEM microscope. It can be concluded that increase of printed ink layers will lead to a better quality of final product in terms of resistance to various environment influences. This research offers insight in the influence of one parameter in textile materials printing process on longevity of flag products, which can also be applied to any other product printed on polyester material. Keywords: Polyester, Ink jet printing, Color fastness, Heat, Light fastness |
DOI: 10.47978/TUS.2024.74.03.018 |
Last changed on 17.11.2024, 20:01:25