JOURNAL OF ENGINEERING SCIENCE

VIBRATION ANALYSIS OF MECHANICAL SYSTEMS WITH MULTIPLE DEGREES OF FREEDOM USING PYTHON

Iulian Malcoci — Sat, 01 Nov 2025 00:00:00 +0000

This study investigates the dynamic behavior of a discrete multi-mass structure, which is highly relevant for engineers seeking to predict and control structural oscillations. The research starts from the hypothesis that numerical modeling and simulation can effectively describe coupled oscillations in systems with several masses and elastic connections. The main objective is to build and solve the equations of motion for a simple multi-degree-of-freedom model using an open-source programming approach. The theoretical background is explained concisely, while the equations are solved numerically with a Python implementation using standard scientific libraries. Modal analysis, eigenvalue computation and time-domain simulation are performed, and the results demonstrate the distribution of energy and the effects of damping. The combined response is visualized through both classic plots and an innovative 3D representation of the coupled displacements. This work confirms that flexible, free numerical tools can be applied successfully to dynamic studies and provides a clear example for engineering education and applied research.

TUNING THE CONTROLLER FOR OBJECT MODELS WITH ONE TO FOUR POLES USING THE POLINOMIAL METHOD

Sat, 01 Nov 2025 00:00:00 +0000

The paper describes the procedure for tuning the controller for control object models with one to four poles using the polynomial method, by imposing the damping ratio and the settling time of the synthesized system. The numerator and denominator polynomials of the object's transfer function are decomposed into components containing zeros in the left and right halves of the complex plane. Based on the order of the object model and the conditions for solving the system of algebraic equations, the physical feasibility of the control algorithm, and the robustness of the system, the desired polynomial of the synthesized system is constructed. This polynomial consists of two sub-polynomials with unknown coefficients, and the degrees and unknown polynomials as well as the degree of the desired polynomial are calculated. From the damping ratio and settling time, the dominant poles of the synthesized system are determined. Based on these poles, the characteristic polynomial of the closed-loop system is constructed, and, if necessary, additional real poles are added as far away as possible from the dominant poles to meet the system's performance requirements. From the resulting equality, by equating the coefficients of the same powers of the variable s on the left and right sides of the equality, a system of algebraic equations is obtained, from which the unknown coefficients and polynomials are determined. Using the stable components of the object model and the unknown polynomials, the transfer function of the control algorithm is constructed. Examples of controller tuning for first-fourth order object models using the polynomial method have been analyzed. The synthesized systems have high performance and good robustness.

FAKE NEWS DETECTION IN MOLDOVA’S INFORMATION SPACE

Maria Smarcevscaia, Victoria Bobicev — Sat, 01 Nov 2025 00:00:00 +0000

This work is devoted to the development of a system for automatic detection of fake news in Russian, relevant for the region of the Republic of Moldova and its neighboring countries. Initially, a representative dataset of fake and real news was collected from the news sites. Several machine learning models were applied for fake news detection, including Naive Bayes classifier, logistic regression, nearest neighbors, support vector machines, and random forest. The results demonstrated that support vector machines and random forest provide the highest accuracy of classification, reaching 91%, which is an impressive result for such difficult task. The developed system helps protecting society from disinformation, which is especially important in the modern world, where the information warfare and political manipulation have become commonplace.

CONTROL-RELEVANT IDENTIFICATION OF THE FIRST-ORDER INERTIAL SYSTEMS WITH TIME-DELAY

Irina Cojuhari — Sat, 01 Nov 2025 00:00:00 +0000

This paper presents an approach for control-relevant identification of inertial systems with time delay. The experimental identification was conducted in closed-loop, and the control object is approximated by a first-order inertial transfer function with time delay. The coefficients were determined using simple analytical expressions based on values obtained from the undamped step response of the closed-loop system with a P controller. This study enhances the understanding of closed-loop experimental identification of inertial systems with time delay and offers effective strategies for synthesizing the PID control algorithm. The obtained results are validated through computer simulation using the MATLAB software package. The results confirm that the proposed identification method for first-order inertial systems provides accurate model estimation and that the control algorithm delivers good system performance.

Ni-DOPED CuO SENSORS WITH CONTROLLED SELECTIVITY AT HIGH OPERATING TEMPERATURES FOR HYDROGEN DETECTION

Sat, 01 Nov 2025 00:00:00 +0000

Gas sensors are of major importance in today's industrial, chemical, agricultural, energy and household fields, and their development for general consumer use is an area of growing interest. This study explores the development and hydrogen sensing performance of CuO nanostructures synthesized via a cost-effective chemical solution method. The nanostructures, composed of copper oxide granules uniformly coated with nickel nanoparticles, were deposited on a glass substrate and thermally treated using rapid thermal annealing (RTA) to minimize defects. The resulting sensors exhibited high hydrogen sensitivity, with responses of 60-70% at elevated temperatures of 300 °C and 350 °C. The uniform deposition of Ni on CuO played a critical role in enhancing both sensitivity and selectivity towards hydrogen gas, while minimizing interference from other gases such as acetone, methane, and ammonia. The sensor demonstrated rapid response and recovery times, further confirming its potential for efficient hydrogen gas detection. These findings suggest that CuO nanostructures offer a promising, cost-effective solution for hydrogen gas sensing applications, particularly in safety-critical environments where hydrogen leaks need to be rapidly detected.

ANALYSIS OF CLOUD BIOMEDICAL HEALTHCARE SYSTEMS SECURITY BASED ON MATRIX REWRITING SRNS WITH FUZZY PARAMETERS

Viсtоr Mоrаru, Alexei Sclifos, Simion Cuzmin, Emilian Guțuleac — Sat, 01 Nov 2025 00:00:00 +0000

This paper presents an analytical uncertainty performability, (especially the security) analysis of Cloud Biomedical Healthcare Systems (CBHS) Security based on Matrix Rewriting Stochastic Reward Nets with Fuzzy parameters (FMRSRN), that allows the compact modeling and evaluation of the impact in which is used a proactive defense time-based Moving Target Defense (MTD) technique. A numerical case study for performability modeling and analysis of a particular CBHS is given to show the effectiveness of proposed method.

EVALUATION OF CYBERSECURITY TRAINING PERCEPTIONS, ADOPTED PRACTICES AND STRATEGIC DIRECTIONS FOR CAPACITY BUILDING

Ludmila Peca, Svetlana Cojocaru, Marius Dumitraşcu, Dinu Ţurcanu — Sat, 01 Nov 2025 00:00:00 +0000

This paper presents the results of a study conducted by the National Institute of Innovations in Cybersecurity CYBERCOR on the impact of specialized cybersecurity training on behaviors related to the protection of personal and professional data. The survey was administered immediately after the completion of the training sessions to a sample of 842 participants from public, private, and academic sectors, aiming to assess the level of awareness and adoption of digital security measures. Data analysis revealed significant increases in the use of security tools and practices, such as performing regular backups, encrypting data, and applying advanced protection programs. The results also highlight differences between participant categories, suggesting that training level and access to resources influence security behaviors. The study confirms the effectiveness of practical, context-driven training but also indicates the need for sustained organizational policies, continuous awareness campaigns, and the integration of user-friendly security solutions. These findings contribute to the development of national strategies for strengthening cybersecurity resilience through education and training.

THE DIGITAL TOOL FOR MANAGING THE DOCUMENT SUBMISSION AND RECEIVING PROCESS OF THE STATE TAX SERVICE

Natalia Burlacu, Alexandru-Laurențiu Bolocan — Sat, 01 Nov 2025 00:00:00 +0000

Digitization has become essential in modern society, transforming the way we live, work, and interact. The state institutions, including those in the Republic of Moldova, are no exception to this process, being faced with the need to adapt and transform to meet new technological requirements and rigors. The Republic of Moldova has developed digitization plans to support this modernization process, ensuring an efficient and effective transition to a digital environment. a few different dispersed modules, which leads to compatibility problems between them; and (3) the technology used previously being outdated and inefficient, as a result, causing a response time that is far too long, followed by the impossibility of managing the requests of the platform users. The present research describes some aspects of the development of a digital tool for solving the aforementioned problem within STS. The present study lies within the field of information and communications technology, with a particular focus on developing software solutions to support public service operations in various state institutions.

REDUCTION OF SODIUM CONTENT IN BAKING THROUGH NEW TECHNOLOGICAL APPROACHES

Corina Caracaci, Georgiana Gabriela Codină, Aliona Ghendov-Mosanu — Sat, 01 Nov 2025 00:00:00 +0000

Excessive sodium consumption is a global public health concern, negatively impacting life expectancy and overall quality of life. Bread, one of the world’s staple foods, contributes significantly to total sodium consumption, making it imperative to reformulate traditional recipes to reduce salt content while maintaining product acceptability. An effective strategy involves gradually reducing the amount of salt, allowing consumers to adapt to a less intense taste. Another approach involves the use of potassium chloride, which can partially replace sodium in the composition of bakery products, but requires adjustments to eliminate the slightly bitter taste. In this process, yeast plays an essential role, as natural fermentation contributes to the development of a more complex flavor profile, amplifying the perception of salty taste and reducing the need for added salt. Another key factor in reducing sodium is the use of flavor enhancers, such as yeast extracts, glutamates and hydrolyzed protein nucleotides, which enhance the perception of saltiness without increasing sodium content. These ingredients can be combined with salt substitutes, thus helping to maintain an optimal taste balance. Implementing these solutions requires an integrated technological approach, which includes product reformulation, nutritional education and public policies aimed at supporting the reduction of sodium in the diet.

MICROBIAL Β-GLUCANS: EXTRACTION METHODS AND STRUCTURAL CHARACTERISTICS – A REVIEW

Aurica Chirsanova, Alina Boiştean, Ana Chioru — Sat, 01 Nov 2025 00:00:00 +0000

The growing interest in functional food ingredients and sustainable bioresources has increased the scientific focus on microbial β-glucans. These polysaccharides are recognized for their immunomodulatory, antioxidant, and prebiotic activities, with potential to improve human health and support innovative biotechnological applications. The present review is based on the hypothesis that the structural diversity of β-glucans significantly influences both their bioactivity and their suitability for industrial utilization. The main objective is to analyze the extraction and purification methods applied for recovering β- glucans from microbial sources, highlighting the relationship between molecular structure and functional properties. Classical techniques such as hot water and enzymatic extraction are compared with modern strategies including ultrasound-, microwave-, and supercritical fluid-assisted methods. Findings indicate that extraction efficiency, yield, and purity strongly depend on the method employed, while hybrid approaches enhance both bioactivity preservation and environmental sustainability. Microbial β-glucans show promising applications in food, pharmaceutical, biomedical, and cosmetic sectors, while safety considerations regarding microbial contamination and immunogenicity remain essential. The review concludes that advances in processing technologies, together with standardized characterization, will contribute to optimizing β-glucan production and to expanding their role as multifunctional bio-ingredients.

SAFETY AND MICROBIAL DYNAMICS OF HIGH-MOISTURE EXTRUDED PROTEIN SYSTEMS UNDER CHILLED STORAGE

Nаtаliа Nеtrеbа, Iuliana Sandu, Viorica Bulgaru — Sat, 01 Nov 2025 00:00:00 +0000

Growing consumer demand for environmentally sustainable protein alternatives has intensified research into the safety and quality of plant-based meat alternatives. This study evaluates the microbiological stability of extruded products with high moisture content obtained from soy and pea protein isolates, as well as composite formulations with the addition of soryz flour, hazelnut meal, and chickpea flour. Ten samples were produced using two industrial extrusion temperature profiles (40–60–80–100 °C and 60–80–100–120 °C) and stored in a refrigerator (+4 °C) for 24 days. Pea protein izolate blends with grain and nut components processed at a milder temperature profile demonstrated excellent microbiological stability, which can be explained by improved water-binding and microstructural properties. These results highlight the practical importance of formulation and extrusion parameters in the development of microbiologically safe plant-based meat alternatives. The study provides industry-relevant information for the development of stable, high-moisture extruded protein products without the use of chemical preservatives.