Texas Journal of Engineering and Technology
Texas Journal of Engineering and Technology provides the opportunity to the authors to publish their original research articles in field of Engineering and Technological Advancements. Frequency of Publication: Monthly Acceptance Notification: 45 Days ISSN (Online): 2770-4491 doi Prefix: 10.62480
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Mathematical Modeling and Investigation of Optimal Operating Modes of a Micro Hydropower Plant Hydraulic Turbine
This paper investigates the determination of optimal operating parameters of a micro-hydropower plant hydraulic turbine equipped with bucket-type blades, designed to operate under variable water discharge and head conditions. The process of converting the hydraulic and kinetic energy of the water flow into mechanical energy is mathematically modeled, and the interrelationships among the main geometric and energy parameters of the hydraulic turbine are analyzed. The relationships between water discharge, hydraulic head, turbine rotational speed, torque, mechanical power, and efficiency are determined based on analytical expressions. In addition, a computational algorithm is developed to determine the optimal installation angle of the bucket-type blades and to select the optimal operating conditions of the hydraulic turbine. Based on the computational results, the optimal turbine parameters are evaluated for operating conditions with a water discharge varying within the range of 0.003–0.009 m³/s. It is determined that, at a hydraulic head of 30 m and a total water discharge of 0.018 m³/s, the optimal rotational speed of each hydraulic turbine is 540 rpm, while the mechanical power is 2150 W. The total mechanical power transmitted from the two hydraulic turbines to the generator is 4300 W. These results demonstrate the feasibility and effectiveness of the proposed turbine configuration for operation under variable water-flow conditions
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Bilateral Compression and Bending of a Plate with All Edges Elastically Fixed (Approximate Solution)
In this paper, we consider the solution to the problem of a plate elastically fixed at all edges with thin-walled open-profile rods and subjected to simultaneous bilateral compression and transverse loads of intensity q
Seismic Resistance Assessment of a Cylindrical Steel Oil Storage Tank under Different Liquid Filling Levels: A Case Study of Fergana City
This article presents the assessment of the seismic resistance level of reservoirs used in the oil and oil-gas industry and examines the conditions required to maintain their structural stability under dynamic loading. The study includes the analysis of existing operating reservoirs using the LIRA-SAPR 10.12 software package, with particular emphasis on the evaluation of equivalent stress results. Furthermore, the distribution of equivalent stresses occurring in the plates of a cylindrical steel reservoir structure was analyzed based on calculation results obtained for liquid filling levels of 50%, 75%, and 100%.
International standards and scientific approaches to managing the supply chain of goods through customs control in world experience
This article provides a comprehensive analysis of international standards, conventions, and leading scientific approaches to managing commodity supply chains through customs control within the framework of the modern global economy. The study delineates the essence and significance of the World Customs Organization's SAFE Framework standards, the World Trade Organization's Trade Facilitation Agreement, UNECE recommendations, and the institutions of Authorized Economic Operators. Furthermore, it scientifically and methodologically substantiates the interrelation of the Kyoto, Istanbul, and TIR conventions—which constitute the cornerstone of international customs law—and evaluates their impact on the sustainability of the supply chain. The paper conducts a comparative analysis of 8 key scientific approaches in the field, highlights their potential opportunities and challenges in modernizing the customs system of Uzbekistan, and proposes a new integrated approach model.
Design Assessment of a Locally Fabricable Air-to-Air Plate Heat Exchanger for Indirect-Direct Evaporative Cooling
This study examines a locally fabricable air-to-air plate heat exchanger used as the indirect stage of an indirect-direct evaporative cooling (IDEC) system. The work uses the TRNSYS 18.0 system model and the HTRI Xchanger Suite 7.3.2 plate heat-exchanger specification reported for a low-cost solar-assisted evaporative cooling system. The selected core is a 65-plate SS304 air-to-air exchanger with 327 mm plate length, 249 mm plate height, 0.6 mm plate thickness, 4.5 mm nominal gap, 101.6 mm port diameter, 32 hotair channels, 32 cold-air channels, countercurrent flow arrangement and 0.33 m² effective heat-transfer area per plate. The direct evaporative cooling (DEC) outlet temperature varied from 17.90 °C to 30.35 °C over the reported daily period, while the IDEC outlet temperature remained within 19.15-19.32 °C. The mean cooled-air temperature was 24.75 °C for DEC and 19.23 °C for IDEC, with corresponding mean cooling efficiencies of 64.05% and 91.30%. These results show that the plate exchanger can provide useful sensible pre-cooling and a steadier supply-air condition under warm-humid conditions in South-South Nigeria. Leakage, pressure drop, flow distribution and heat-transfer effectiveness still require prototype measurement.
Comparative Analysis of Wind Resource Potential and Turbulence Intensity for Small-Scale Power Generation in Coastal Nigerian University Communities
This paper evaluates wind-resource potential, monthly wind-speed variability, and small-scale powergeneration suitability at the University of Uyo Main Campus in coastal Akwa Ibom State, Nigeria. Ten years of wind-speed records from the Nigerian Meteorological Agency for 2011-2020 were combined with site-level field measurements collected in July 2021 at five campus locations. The NIMET records were used for climatological assessment, annual wind-speed classification, Weibull distribution fitting, and coefficient-of-variation analysis. The campus measurements were used to compare micro-siting effects across locations with different terrain exposure and obstruction levels. A rotor-level CFD interpretation was also used to relate the reported torque result to possible mechanical power. The decadal annual mean wind speed was 2.26 m/s, while the mean of the monthly climatological averages was 2.41 m/s. Site 2 recorded the highest mean speed of 3.1 m/s and wind power density of 20.13 W/m², while Site 5 recorded only 1.6 m/s and 2.60 W/m². The coefficient of variation of the monthly mean wind speed was about 0.18. This value is interpreted as a monthly wind-resource variability indicator, not as measured turbulence intensity, because the available record does not contain short-interval wind-speed fluctuations. The CFD torque value of about 3.2 N·m corresponds to limited mechanical power and must be interpreted together with rotor speed, drivetrain efficiency, generator efficiency, storage losses, and actual load demand. The results do not support utility-scale wind generation at the study location. They indicate, however, that carefully sited lowcut-in-speed micro-wind systems may support limited loads such as LED lighting, small electronics charging, sensor nodes, and hybrid wind-solar battery systems.
Early Detection of Transformer Winding Faults Using Multimodal Vibration and Acoustic Sensor Data Fusion with Deep Learning Acoustic Sensor Data Fusion with Deep Learning
Early changes in transformer winding geometry often appear as weak mechanical and acoustic signatures before they develop into insulation breakdown, severe inter-turn short circuit or service failure. This paper presents a non-invasive vibro-acoustic deep learning framework for early winding-fault detection. Synchronized vibration and acoustic recordings were obtained from a controlled 15 kVA, 11/0.415 kV, 50 Hz oil-immersed laboratory transformer under healthy operation and four emulated early-fault states. Vibration windows were represented as continuous wavelet transform scalograms, while acoustic windows were represented as Mel-spectrograms. A dual-branch CNN-BiLSTM model with additive attention was used to learn each sensing channel before feature-level fusion and five-class classification. The dataset comprised 600 raw recording runs and 7,200 synchronized windows. The split was performed at raw-run level before segmentation-based learning to prevent leakage among overlapping windows. Across five independent training runs, the fusion-attention model achieved 98.92 ± 0.24% accuracy, 98.61 ± 0.27% precision, 98.47 ± 0.29% recall and 98.54 ± 0.26% F1-score on the held-out test set. The results indicate that paired vibration and acoustic evidence improves early recognition of winding looseness, axial displacement, radial deformation and incipient inter-turn weakness under the controlled test conditions. The method provides a laboratory-validated alarm layer whose substation use should be checked against established maintenance evidence from frequency-response analysis, dissolved-gas analysis, thermal inspection and expert review
Probabilistic Forecasting of Renewable Energy Output Under Uncertainty Using Deep Quantile Learning: A SolarPV Case Study
Renewable generation varies with irradiance, cloud cover, temperature, seasonal effects, ramp events and measurement uncertainty in solar-PV systems, while similar uncertainty arises from wind speed and turbulence in wind generation. A single deterministic forecast is therefore not sufficient for reserve scheduling, storage dispatch, market bidding or real-time balancing. This paper presents an attention-based convolutional neural network-bidirectional long short-term memory (CNN-BiLSTM) quantile-regression model for probabilistic renewable-energy forecasting. The model was trained and evaluated on a curated hourly solar photovoltaic subset derived from the ECMWF Ensemble Prediction System solar forecasting dataset. Lagged PV output, ensemble weather predictors, calendar terms and ramp-related variables were used to estimate the 0.05, 0.10, 0.25, 0.50, 0.75, 0.90 and 0.95 conditional quantiles. The 0.50 quantile served as the median point forecast, while the 0.05 and 0.95 quantiles defined the 90% prediction interval. On the held-out test set, the proposed model achieved MAE of 0.041 p.u., RMSE of 0.060 p.u., MAPE of 5.95%, R² of 0.954, mean pinball loss of 0.038, CRPS of 0.044, PICP of 89.1%, PINAW of 0.252 and Winkler score of 0.128. Compared with the strongest Transformer-quantile baseline, the model reduced mean pinball loss from 0.041 to 0.038 and narrowed the interval width from 0.265 to 0.252 while keeping empirical coverage close to the nominal 90% level. The improvement is modest, but it is consistent across probabilistic loss, empirical coverage and interval-width metrics, which is important for short-term operational use
Vibration Analysis and Material Optimization of an OilInjected Screw Compressor Using Experimental Measurements, Finite Element Modal Analysis, and CFD Simulations
Oil-injected screw compressors are widely used in compressed-air, refrigeration and gas-handling plants because they deliver steady flow from a compact rotating machine. In service, vibration at rotor, bearing, gear and support interfaces can shorten bearing life, increase leakage, raise noise and cause unplanned shutdown. This study examines the vibration behaviour of an Ingersoll Rand R110i oil-injected screw compressor by combining five-month field measurements, finite element modal interpretation, a simplified flow-path assessment and component material screening. Vibration was measured at the compressor and motor drive-end and non-drive-end locations in the horizontal, vertical and axial directions using an SKF Microlog analyser in RMS velocity mode. The highest measured value was 31.75 mm/s at the motor nondrive-end vertical point. Compressor-side readings were much lower and more stable, showing that the dominant field problem was concentrated at the motor support path rather than across the compressor body. A SolidWorks-based assembly model was used to compare materials for the rotors, casing, bearings, gears and damping elements. The selection process considered density, stiffness, fatigue strength, corrosion or wear resistance, damping capacity, manufacturability and cost. The selected configuration was Ti-6Al-4V for the rotors, ASTM A48 Class 35 cast iron for the casing, silicon nitride for the bearings, AISI 8620 casehardened steel for the gears and polyurethane for the damping elements. Under the linear-elastic and simplified-support assumptions used in the model, the optimized assembly gave a simulated response velocity of 3.1496 × 10−4 mm/s and a maximum Von Mises stress of 379.6 psi. The velocity value is a numerical response indicator from the model, not a measured operating vibration value. The simplified flow assessment showed gradual pressure development across the rotor-casing path, with no pronounced recirculation pocket or velocity bottleneck. The study recommends two actions: immediate correction of the motor non-drive-end support condition and later prototype validation of the selected material configuration
Determination Of Optimal Tilt Angle For Solar Photovoltaic Panels In The Southern Regions Of Uzbekistan
This article examines the trends in the development of solar energy in Uzbekistan, the solar energy potential, and the methodology for determining the optimal installation angles of solar panels. The optimal tilt angles of solar photovoltaic panels relative to the horizontal surface in Bukhara province were determined. The results showed that the average optimal tilt angle for summer months is 5° (≈ φ – 35°), while for winter months it reaches 65° (≈ φ + 25°). When using seasonally adjusted tilt angles are applied, the total annual collected solar energy amounts to 9252 MJ/m²·year. The annual average optimal tilt angle for south-facing solar panels was evaluated as 36°.
Evaluation Of The Efficiency Indicators Of Electric Vehicle Heating Technology In Cold Climate Conditions
This article analyzes the problems of energy losses and reduced range during the operation of electric vehicles in cold climates. The indicators are presented, which are aimed at reducing energy consumption and increasing the overall operational efficiency of the vehicle by evaluating the efficiency indicators of electric vehicle battery heating technologies and optimizing them. The amount of energy consumed during battery heating and its impact on the overall energy balance are estimated using mathematical models. Optimal operating modes for the thermal management system of an electric vehicle battery are developed, and an algorithm for controlling the heating process is proposed. The control algorithm is aimed at maintaining the battery temperature at the required level with minimal energy consumption, and its adaptation to real operating conditions is described in detail.
Improving the methodology for setting adaptive speed limits and mandatory reductions based on the integrated risk index in mountainous road areas (on the example of mountainous areas of the M-39 road)
This article studies the issue of developing effective mechanisms for mandatory reduction of vehicle speed on mountainous roads. The mountainous areas of the M-39 international highway, passing through the Jizzakh region, within the range of 982–1013 km, were selected as the object of research. During the study, factors affecting the turning radius of the road, longitudinal slope, width of the carriageway, traffic flow intensity, speed, pavement condition and accident probability were studied. A methodology for setting an adaptive speed limit by assessing road geometry, traffic flow parameters and external environmental factors based on a single integrated risk index was proposed
Method And Results For Developing A Device For Electro technological Treatment Of Apple Trees In Intensive Orchards
This study presents the development and evaluation of an electrotechnological device for controlling aphids on apple trees in intensive orchards using UV-C radiation (253.7 nm). The research is based on an analysis of plant diseases, pest control methods, and electrophysical approaches. Field experiments showed that treatment efficiency depends on distance and exposure time. The highest efficacy (98.1%) was achieved at a 0.3 m distance with a double 20-minute treatment, while increasing the distance reduced effectiveness. Economic analysis demonstrated significant cost savings, with the UV-C method reducing expenses by 40,734,000 UZS over three years compared to chemical treatment. The device is simple, portable, energy-efficient, and environmentally safe, making it an effective alternative to chemical pest control.
Development Of The Mathematical Model And Automated Functional-Technological Scheme Of The Rectification Process
This article presents the development of a mathematical model of the rectification process and proposes an automated functional-technological scheme for effective process control. During the research, the heat and mass transfer processes occurring in the rectification column were analyzed, and their mathematical expressions were derived. Based on the developed model, the factors affecting the main process parameters were identified and their interrelationships were studied. In addition, a functional-technological scheme for designing an automated control system was developed, in which measurement, monitoring, and control devices were integrated. The proposed approach makes it possible to improve the stability of the rectification process, reduce energy consumption, and enhance product quality
Environmental Risk Management Based On Management System Requirements
This article presents scientific and practical recommendations for identifying aspects, assessing their significance levels, and reducing negative impacts by creating an environmental risk management organization standard in the production processes of plastic and rubber components for the automotive industry. During the study, an environmental profile for plastic, rubber, and dyeing workshops was formed based on the requirements of the international ISO 14001 standard
Khamrakulova Zarnigorkhon Farkhodjon kizi
Types of anti-detonation devices and the mechanism of their effect on automobile gasoline
Today, a cycle with external mixture formation (gas-diesel cycle) has been developed in which diesel engines are combined with natural gas. Almost all gasoline engines have switched to direct injection into the engine's combustion chamber. Gasoline engines today use not only gasoline, but also natural compressed or compressed petroleum gases, alcohols and alcohol-gasoline mixtures
Development of Fuel Consumption Correction Factors for GTL Synthetic Diesel Fuel in Diesel Vehicles under Field Operating Conditions
This paper proposes a compact operational method for adapting fuel-consumption norms when gas-to-liquid (GTL) synthetic diesel fuel is used in existing diesel vehicles. Field tests were conducted on an ISUZU NQR71PL vehicle operated on petroleum diesel and GTL fuel under comparable conditions. The test indicators included maximum speed, acceleration time to 60 km/h, and fuel consumption at 40-90 km/h. The maximum speed remained practically unchanged (104.17 and 105.50 km/h), while acceleration time increased from 15.91 to 16.86 s. GTL volumetric consumption exceeded diesel consumption by 4.56-6.10%, mainly because of the lower density and lower energy content per litre of GTL fuel. Speed-dependent correction factors of 1.046-1.061 were obtained, and an average value of 1.055 is recommended for preliminary fleet accounting. The results confirm that GTL fuel can be used without major vehicle modification, but separate consumption norms are required
Hybrid Attention-Based Deep Learning for Threat Traffic Recognition in IoT Networks Using the ToN_IoT Dataset
Internet of Things networks generate high-volume, temporally structured traffic whose attack signatures span both within-flow feature patterns and cross-flow temporal dynamics. Single-paradigm classifiers cannot fully exploit this dual structure. This paper proposes HACIDS (Hybrid Attention-based CNN Intrusion Detection System), combining two-stage convolutional feature extraction, Bidirectional LSTM temporal modelling, and Multi-Head Self-Attention (MHA) for eleven-class IoT threat detection on the ToN_IoT dataset. HACIDS achieves 94.78% accuracy and macro F1 of 0.924, modest but consistent improvements over all evaluated baselines, with the most meaningful gains on rare attack categories. Results are from a single held-out split; standard deviation across repeated runs is not reported, which is acknowledged as a limitation. Performance may be partially optimistic due to sliding window overlap; traintest separation was performed before window construction. An ablation study confirms each component contributes incrementally; attention weight analysis provides indicative feature associations per attack class.
Privacy-Preserving Collaborative Defence: Federated Learning for Intrusion Detection on the ToN_IoT Dataset
The rapid proliferation of Internet of Things (IoT) devices across smart homes, industrial automation, and healthcare networks has expanded the cyber-attack surface while generating distributed, privacy-sensitive network telemetry that centralised intrusion detection systems cannot collect without creating regulatory and operational risks. Centralised IDS architectures are less suitable for the distributed, heterogeneous IoT deployment reality and may conflict with data sovereignty frameworks such as the General Data Protection Regulation (GDPR). This paper proposes and evaluates a Privacy-Preserving Collaborative Intrusion Detection System (PP-CIDS) using Federated Learning (FL) on the ToN_IoT benchmark. A lightweight multi-layer perceptron (MLP) is trained through FedAvg aggregation across ten simulated edge clients and compared against centrally-trained Random Forest (RF) and DNN reference baselines. Asynchronous FL with FedProx regularisation is evaluated against synchronous FL for convergence efficiency and communication overhead. The impact of Non-IID data heterogeneity is quantified using Dirichlet concentration parameter α ∈ {0.5, 0.1}. All results are reported as mean ± standard deviation across five independent runs. Under IID conditions the federated MLP achieves 89.12% ± 0.63% accuracy, within 3.1 pp of the centralised DNN reference (92.2%), without transmitting raw traffic data. Asynchronous FL with FedProx under severe Non-IID heterogeneity (α = 0.1) achieves 84.21% ± 0.84%, demonstrating that privacy-enhancing federated IoT IDS is viable even under significant data heterogeneity, while acknowledging that FL alone does not guarantee full regulatory compliance
Correlation and regression model of medical clinic quality indicators through ISO 9001:2015 and ISO 7101:2023 standards
In this article, quality indicators were studied based on international standards ISO 9001:2015 and ISO 7101:2023, and an empirical-statistical analysis was conducted based on the identified quality indicators. The identified model was tested for adequacy based on Student’s and Fisher’s criteria. The identified regression equation was confirmed by statistical analysis (Fisher F-criterion p < 0.001) and high determination coefficients (R2 > 0.94). The models were constructed based on Student’s t-test, and the statistical significance of all regression coefficients was determined. The results of the empirical-statistical analysis show that the application of the requirements of the ISO 9001:2015 and ISO 7101:2023 standards have a direct impact on the determining changes in the quality of medical laboratory services. The identified quality indicators and mathematical models can be applied in other medical laboratories.
indicator, standard, ISO 9001:2015, F-criterion, model.
Improving The Service Life of Road Concrete Under The Effect of Mineral and Chemical Additives
In the Republic of Uzbekistan, the construction of modern toll roads and highways represents a key infrastructure component that ensures the efficient functioning of transport networks globally. While asphalt and concrete materials traditionally used in road construction have proven somewhat effective, they face challenges related to long-term strength, durability, and environmental impact. This study analyzes composite materials that are fundamentally transforming road and highway construction practices and highlights their potential to overcome existing issues. It evaluates the operational efficiency of complex modified materials in road construction, emphasizing how mineral and chemical additives enhance concrete and pavement strength, resistance to deformation, cold, and aggressive environments. The findings indicate that employing these materials can extend infrastructure service life, reduce maintenance costs, and support environmental sustainability.
Seismic Strength Assessment of An Oil Product Storage Tank Under Full Product Filling Conditions
This study presents technical solutions aimed at reducing the seismic vulnerability of existing storage tanks. Scientific and engineering proposals are developed to enhance the seismic resistance of the tank, and structural strengthening measures are formulated based on numerical analyses performed using the LIRA-SOFT 10.12 software package. Based on the obtained results, effective engineering solutions are proposed to mitigate seismic impacts and improve the overall structural safety and reliability of the tank.(This article was prepared within the framework of the project of the Ministry of Higher Education, Science and Innovation of the Republic of Uzbekistan on the topic of determining the level of seismic resistance of reservoirs in the oil and oil and gas industry and developing measures to reduce seismic risk, scheduled for implementation in 2024-2025)
Assessment Of The Safety Of Ultrasonic Equipment Using The Fmea Method
In this article, we conducted research on the safety of ultrasound equipment using the FMEA method. The work performed in this study was carried out in accordance with the requirements of the international standard “IEC 60601-2-37:2024 Particular requirements for the basic safety and essential performance of ultrasound medical diagnostic and monitoring equipment” and “ISO 14971:2019 (E) Medical devices - Application of risk management for medical devices”. The study was conducted at the “YYY” diagnostic center in Andijan. The study is based on the results obtained from 150 patients over a three-month observation period. During the study, the initial average RPN level was 175.8, and due to corrective measures, it was reduced by 44.7, or 74%. The work in the study is part of the results of my scientific research on the topic “Improvement of the quality assurance system for ultrasound examinations in medicine based on international standard requirements”
The Pedagogical Significance of the Ideas of Labor Education and Career Choice in the Heritage of Eastern Scholars
This article analyzes the pedagogical significance of ideas related to labor education and career choice in the spiritual heritage of Eastern scholars. The study examines the views of Abu Nasr Forobiy, Abu Rayhon Beruniy, Abu Ali ibn Sino, and Alisher Navoiy, highlighting their perspectives on labor, professional skills, and personal development. The article reveals the role of labor as a means of achieving personal maturity, its importance in social development, and its close connection with moral education. It also substantiates that labor education contributes to the formation of essential personal qualities in students, such as responsibility, discipline, patience, and independence. The research findings indicate that the ideas of Eastern thinkers serve as an important methodological basis for guiding students toward professional orientation. It is emphasized that the integration of these ideas into the educational process can enhance students’ conscious career choice, as well as develop their diligence and independent thinking skills
Bibliometric Analysis Of Overall Equipment Effectiveness (OEE)
Overall equipment effectiveness (OEE) is a key performance indicator used to measure equipment productivity(Overall equipment effectiveness 2008). The purpose of this study is to review and analyze the scientific papers written on OEE(Tang Ho Hwa, Yeo Chiew Tiam, and Ding See Kong 2020). 1377 documents were obtained in the general search; after eliminating duplicates and applying certain inclusion and exclusion criteria, 1308 papers were used for this review. This study provides three main conclusions: During the period 2000-2022, academic interest in this topic has increased and the keywords are maintenance and production, related to the six major losses, lean manufacturing and optimization; a list of authors who have conducted scientific work on the basis of OEE is compiled; and the top 10 countries that conducted scientific work based on OEE are presented based on geographical analysis. VOS viewer software was used to investigate the bibliometric research method and bibliographic display maps(Vinodh 2022; Wudhikarn 2012; Yeo, Chang, and Liu 2021). There are three phases to the bibliometric research process, they are search criteria and source identification, software and data extraction, and then data analysis and interpretation. To our knowledge, several bibliometric comparative reviews on OEE and maintenance have been published. This study serves as a continuation of the above related studies.
Advantages And Disadvantages Of Using Virtual Laboratory Work In Physics
In this paper we have considered the problem of implementation of virtual physics labs in higher education institutions, as well as their advantages and disadvantages compared to traditional laboratory practical’s. The importance of supplementing real experiments with virtual ones is highlighted. It is shown that the virtual laboratory is one of the innovations having a significant impact on the modern education system. The virtual laboratory provides practical training with all the existing limitations, such as the tools and materials of practical equipment at universities
Stability Conditions In Black Hole Problems
This paper presents a systematic theoretical review of stability conditions in black hole spacetimes. Four interconnected aspects are examined: linear perturbation theory and its effective potential structures, quasinormal mode analysis including spectral instability, nonlinear stability and its rigorous mathematical proofs, and thermodynamic stability covering heat capacity and phase transitions in anti-de Sitter spacetime. The observational connection to gravitational-wave ringdown signals is discussed as empirical validation of the perturbative stability framework. Key open problems are identified alongside prospects offered by next-generation gravitational-wave detectors.
The influence of rare earth elements on the optical properties of silicon epitaxial films
The results of growing erbium-doped silicon epitaxial layers using two different growth modes are presented: conventional molecular beam epitaxy (MBE) and solid-phase epitaxy (SPE). It is shown that an erbium-doped silicon layer deposited by PFE on a cold substrate and subsequently annealed exhibits more intense photoluminescence at a wavelength of 1.54 µm than layers grown by MBE
Criteria for Food Product Quality and Safety, Analysis of Factors Affecting the Effectiveness of a Food Safety Management System (FSMS)
ISO 22000:2018 specifies requirements for a Food Safety Management System (FSMS) for organizations in the food chain and integrates Codex and HACCP principles. This paper aims to systematize quality and safety criteria for food products using clear indicators and limit values, assess drivers that influence FSMS performance, and propose a composite FSMS Performance Index (FSMS-PI) based on key performance indicators (KPIs). The methodology was built on the Codex CXC 1-1969 (Rev. 2020) GHP/HACCP approach, ISO/TS 22002-1:2009 prerequisite programme (PRP) requirements, and limit values from relevant product standards. As illustrative objects, a criteria registry was developed for wheat flour and refined vegetable oil. For wheat flour, moisture content ≤15.5% (m/m) was selected as a core quality indicator. For refined vegetable oils, acid value ≤0.6 mg KOH/g, peroxide value (PV) ≤10 meq O₂/kg, and limits for Cu ≤0.1 mg/kg and Fe ≤1.5 mg/kg were set as baseline indicators