A low earth orbit satellite descent strategy

The object of the article is the method of descending a satellite from low Earth orbit (LEO) at the end of its service lifetime for its disposal. The main problem is to ensure a safe and cost-effective disposal of the satellite while minimizing risks to the environment and other objects in orbit. Based on the method, calculations were made for lowering the orbit and directing the satellite to a remote area of the Earth’s ocean. The calculations included braking pulses, fuel consumption, descent time to the burial orbit, and the time for natural descent before reaching the Earth's surface. The descent process is divided into three stages: active descent using low-thrust engines (LTE), passive descent due to natural braking in the out-of-atmosphere part, and fall through the dense atmosphere. Dependency graphs were provided to illustrate orbit altitude, satellite speed, reentry angle changes, and flight range over time. The findings revealed that combining active orbital maneuvers with passive orbital decay optimizes the deorbiting procedure by minimizing fuel requirements and operational complexity. The proposed strategy ensures the satellite-controlled re-entry and safe disposal, significantly reducing the risks of collisions and environmental impact. The results solved the problem by defining a staged satellite descent process. Duration were computed for active descent with braking impulses for uniform altitude reduction and passive descent due to atmospheric drag. The trajectory and duration of fall in atmosphere. The process ensures controlled re-entry and safe disposal. This method is suitable for satellite operators and space agencies handling LEO mission

Rapid assessment of risks in tug operations within port areas

Summary: This article presents a rapid risk assessment methodology specifically designed for tug operations within port areas, addressing the unique challenges of these high-risk environments. Tug operations require efficient risk mitigation due to confined spaces, unpredictable environmental conditions, and potential human factors that may lead to incidents. Traditional, detailed risk assessment models are often impractical in real-time scenarios. Therefore, this study focuses on developing a streamlined, quantitative approach for assessing and managing risks in port towage. The paper introduces an enhanced Risk Factor (RF) model as a key component of the proposed methodology. Traditionally, the RF is calculated using the formula RF=P×C, where P denotes the probability of occurrence, and C represents the severity of the consequence. This study expands on the conventional formula by including two additional elements relevant to towage: E (Environmental Conditions) and H (Human Factors). Thus, the modified formula RF=P×C×E×H provides a more comprehensive risk profile for rapid assessment in dynamic port conditions. Each section of this paper systematically explores the variables of the extended RF model and applies it to common scenarios in port tug operations. The findings demonstrate that incorporating environmental and human factors into the RF calculation enhances the model’s reliability and relevance. Finally, the paper provides recommendations for implementing the proposed RF methodology, supporting port operators and tug crews in real-time risk assessment and decision-making, thereby ensuring safety outcomes, minimizing possible risks involved, and improving maritime safety overal

Study of the resonant motion of a test particle inside Kepler 69 using circular restricted three body problem

Summary: Scientific researches to discover extraterrestrial life are very intense and important. For a long time, humanity has speculated about the existence of the planetary systems different from our solar system, where extraterrestrial life can be existing elsewhere in the universe. The understanding of the origin of planets and planetary systems has indeed become a major focus of research in modern Astrophysics. Exoplanet research is one of the most field developing subjects in Astrophysics and Astronomy. Today, the number of discovered exoplanets, where life is thought to exist, is large. One of the main goals of scientists is to find Earth 2, where there is possibility of extraterrestrial life. Kepler's mission was, and is very important in the field of exoplanet research. This mission has revolutionized our understanding of exoplanets. The number of discovered exoplanets has exceeded 5780 in 4314 planetary systems, with 969 systems having more than one planet [1]. Among them, one of the most interesting is Kepler 69 c, a super-Earth around Kepler 69. This exoplanet is located at the boundary between the habitable zone and the outer one. In this study let’s focus on the classical gravitational problem called Circular Restricted Three-Body Problem (CRTBP) [2, 3] and use an iterative method to perform numerical calculations through MATLAB software. Therefore, in this paper, let’s try to study the movement of a “test particle”, under the action of the gravitational field of the system Kepler 69–Kepler 69 c. The aim of this paper is to study the motion of a “test particle” (for example an extrasolar asteroid test) inside the exoplanetary system Kepler 69. Results are presented in the (x, y) plane in the rotating and inertia system. Also, some of the results are presented in the phase planes (x, vx) and (y, vy

InGraph Platform: a new resource of scientific works with an expanded scientometrics tool

The paper presents a scientific and practical development of an information technology product – the InGraph Platform. The logic, structure, and information technology implementation of this Platform provide a practically useful service for all subjects of scientific activity who create scientific works and use them: authors, reviewers, and end users from science and practice. The Platform mechanisms, which ensure interaction between all its users, form a technology of scientific and practical communications based on the principle of “everyone gets what they need with minimal waste of time”. The InGraph Platform concept implements the transition from the one-dimensional model of “scientist for scientist” or “science for science” to the two-dimensional model of “science for improving human well-being”, setting as a priority for science the provision of practical needs for the results of scientific research, rather than the number of citations or the h-index. At the same time, the use of the platform completely eliminates the intermediary in the form of a publisher, preserving the copyright of the author and ensuring honest and transparent communications between authors and users of scientific work

Parametric classification based on kinematic characteristics of objects for identification of criminals

The problem of identifying objects in conditions of their disguise and impossibility of assessment by video images is studied. Potential criminals can be considered as such objects. The task is to assess whether the observed object is a potential criminal element or an ordinary person.It is proposed to use kinematic characteristics of human motion as factors-features for solving the recognition problem, in particular, components of the speed and acceleration vectors of characteristic points of the body in the system of generalized coordinates using Lame functions.It is proposed to use a parametric classification algorithm to solve the identification problem with such a choice of factors-features. The proposed idea, if practically implemented, can create conditions for detecting criminals or identifying suspicious persons for subsequent control check

Optimizing agricultural transportation: advancing the 'transportation problem' towards intelligent solutions

Ensuring food security has always been one of the main priorities of human society. This problem is more pronounced today. Studies show that most food products are spoiled during transportation. This once again clearly demonstrates how urgent the issue of optimizing the transportation of food products is. A number of studies, articles and important results are found in the scientific literature aimed at solving the problem of optimizing transportation. The object of research in the presented article is the transportation of food products. The article proposes a solution to the problem of eliminating the imbalance between the production and demand of agricultural products. The issue is solved by bringing it to the “Transportation issue”. First of all, the amount of products produced by the farmers and the demand for products by region are determined. In the second stage, a cost table is compiled to determine the transportation costs between production points and demand points. After that, the first possible transportation plan is compiled using the North-West corner method. The optimality of the plan is checked. If the plan is not optimal, the next possible plan is compiled. The number of possible plans is found and it is explained that this problem is impossible to solve manually. For this purpose, a list of programs in the Python algorithmic language is presented to find the optimal placement plan more quickly. The presented method is useful in solving the transportation problem, but can also be applied in other areas of agriculture. Thus, the presented method can be applied to eliminate the possible imbalance between the mineral and fertilizer needs of soil and plants for productivity management

Increasing energy efficiency by improving navigation methods

This paper presents an innovative approffach to improving vessel energy efficiency through enhanced navigation methods, addressing the growing need for fuel consumption optimization in maritime transportation. Traditional approaches to vessel energy efficiency often focus on technical solutions, while the potential for optimization through improved navigation methods remains underexplored. The study introduces a comprehensive model for energy efficiency assessment that considers multiple operational factors affecting fuel consumption during vessel transit. The research proposes an enhanced methodology that integrates three key components: ballast optimization, trajectory control, and specific fuel consumption management. The study demonstrates that energy efficiency can be significantly improved by optimizing these components through mathematical modeling and real-time operational adjustments. The findings indicate that proper implementation of the proposed methods can lead to considerable fuel savings while maintaining required safety standards and operational effectiveness. The paper provides a systematic approach to energy efficiency optimization, supported by mathematical models and practical recommendations for implementation. The results demonstrate the potential for significant reduction in fuel consumption through improved navigation methods, contributing to both economic efficiency and environmental sustainability in maritime operations. Further researches and enhanced methodology development for each vessel`s energy efficiency component stated in this article may potentially reduce fuel consumption even mor

Epitaxial growth and characterization of gan thin films on 2D MoS2 substrates via plasma-assisted molecular beam epitaxy

Gallium nitride (GaN) is an excellent material for high-performance optoelectronic and power electronic devices due to its superior thermal conductivity and exceptional electron transport properties. However, growing high-quality GaN films is challenging because of lattice mismatch and thermal expansion coefficient differences with conventional substrates like sapphire and silicon, resulting in threading dislocations and structural defects that compromise device performance. This study addresses these issues by utilizing a 2D-MoS₂ buffer layer, which provides an atomically smooth surface and quasi-van der Waals interface to minimize lattice mismatch stress and suppress defect propagation. GaN thin films were grown on MoS₂-deposited c-sapphire substrates using plasma-assisted molecular beam epitaxy (PA-MBE) under optimized conditions. The MoS₂ layer was prepared using a chemical vapor deposition process followed by nitridation. Characterization techniques, including Reflection High-Energy Electron Diffraction, Atomic Force Microscopy, Field Emission Scanning Electron Microscopy, and X-ray Diffraction, confirmed that the GaN films exhibited high crystallinity, phase purity, and preferred c-axis orientation, with minimal structural defects. Surface analysis showed moderate roughness, with a root mean square value of 11.35 nm, attributed to localized growth variations. The MoS₂ buffer layer significantly reduced lattice mismatch-induced stress, as indicated by the absence of secondary phases in XRD analysis and facilitated defect-free epitaxial growth. These findings demonstrate the transformative potential of combining PA-MBE with 2D material buffers to achieve high-quality GaN films. This approach holds promise for optoelectronic applications such as LEDs and laser diodes, as well as high-frequency electronic devices like high-electron-mobility transistor

Analysis of potential risks during the control of an unmanned underwater vehicle (UUV)

This article explores the analysis of potential risks associated with controlling unmanned underwater vehicles (UUVs), focusing on operational, environmental, and technological challenges. UUVs play a critical role in marine research, defense, and offshore industries but are subject to unique risks due to limited visibility, communication latency, and unpredictable underwater conditions. While UUVs have revolutionized underwater exploration and navigation, their reliance on advanced technologies introduces unique challenges. The study identifies the primary risk domains of UUV operations, including operational risks, human-machine interaction vulnerabilities, and environmental unpredictability. Using comprehensive scenario analysis and data from practical implementations, the article evaluates key risks such as navigation errors, system malfunctions, and communication disruptions. It further examines how artificial intelligence (AI) can be leveraged to mitigate these risks through real-time trajectory optimization, adaptive learning, and enhanced situational awareness. This research incorporates scenario-based analyses for UUVs to evaluate the most critical risk factors affecting mission safety. Furthermore, it explores how modern technologies can mitigate these risks by enhancing trajectory optimization and monitoring of UUVs during underwater navigation. By providing a holistic understanding of UUV risks, the findings underscore the need for robust control systems and operator training protocols. The research contributes actionable insights for improving UUV safety, efficiency, and reliability, laying the groundwork for further advancements in maritime robotic

Identification of the degree of greenness of the proposed skills with the requirements of green jobs based on fuzzy logic

The deepening climate crisis development have prompted most countries to recognize the importance of transition to a green economy. This causes a rapid growth of “green” jobs in various spheres of human activity and, accordingly, the need for “green” skills necessary to use new technologies. New professions and specialties requiring the acquisition of green skills create a discrepancy between the demand for human resources of the required profile and their supply. In this context, it was clarified what the terms green jobs and green skills mean. Considering the content of these two concepts, studies dedicated to determining the relationship between the green transition and relevant skills were reviewed. In this regard, the selection of personnel with the necessary skills determines the relevance of developing methods for assessing the supply and demand for specialists, providing an opportunity to assess the compliance of the proposed skills with the requirements of green jobs. This article proposes a methodological approach to intelligent management of supply and demand in the green segment of the labor market. It also develops decision support methods to identify of compliance the greenness degree of the proposed skills with the level of the requirements of green jobs. Decision making methods were based on fuzzy situational analysis and pattern recognition: reference situations are determined (fuzzy reference pattern), real situations are determined (fuzzy real pattern); degree of green similarity of the reference situation to each real situation is calculated in accordance with the chosen measure of assessment of similarity between two fuzzy situation