Maintenance, Reliability and Condition Monitoring
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Alternative progressive stamping injection determination by eddy current sensors readings
Full text linkThe study discusses the accuracy of eddy current sensors in measuring material thickness, during production process with a maximum deviation of 25,3 µm. It presents a comparison table of calibrated plates and sensor readings, highlighting certain discrepancies attributed to measurement techniques, random errors and sensor positions. The experiment's findings show that by implementing sensors it is possible to monitor process in real time and adjust parameters accordingly
Study on craniocerebral dynamic response and helmet protection performance under accompanying shock wave
Full text linkTo systematically investigate the protective effects of helmets against human head injuries under various shock wave conditions, a finite element head-helmet coupling model was developed. This model analyzed how helmets influence biomechanical response parameters, such as intracranial and cranial pressure, when subjected to a single blast wave and its accompanying shock wave. While extensive research exists on single blast scenarios, studies on the more complex and militarily relevant accompanying shock waves, which pose a greater threat due to prolonged loading and multiple reflections, remain scarce. Several impact scenarios were considered, including single frontal impact, positive continuous impacts, successive sidewall impacts, and simultaneous frontal and lateral impacts. The study examined the dynamic changes in brain tissue within a blast environment to assess the efficacy of helmets in protecting the human head. In single frontal impact scenarios, helmets effectively reduced intracranial pressures in the frontal, occipital, and parietal lobes by 32 %, 38 %, and 19 %, respectively, while significantly decreasing the stress peak at the back of the skull. During positive continuous impacts, helmets decreased intracranial pressure in the parietal and occipital lobes by 36 % and 21 %, respectively, although their effectiveness in reducing frontal lobe pressure was limited due to inadequate facial protection. For successive sidewall impacts, helmet protection delayed the blast wave, reducing intracranial pressure in the frontal lobe by 60 kPa but increasing pressure in the parietal lobe by 80 kPa. This alleviated stress on the skull’s rear while increasing stress on the opposite side. In scenarios involving simultaneous frontal and lateral impacts, lateral blasts increased parietal intracranial pressure by 20 kPa, with the right hemisphere experiencing more pressure than the left due to the mitigating effect of reflective side blasts on skull stress. The study found that, compared to single blast waves, accompanying shock waves present a greater risk of cranial injuries due to their prolonged impact. These findings address a critical gap in blast neurotrauma research and provide valuable insights into the biomechanics of head injuries under realistic multi-blast conditions, which can directly inform the design of improved helmets with enhanced protection in complex blast environments. However, because shock waves may originate from multiple directions and elevations, the protective capability of conventional helmets for the facial region remains limited
The airflow behavior of light particulate materials during free fall and their impact dynamics on screening surfaces
Full text linkTo optimize the efficiency and noise performance of high-frequency vibrating screens, this study investigates the airflow behavior of lightweight materials during free fall and their impact dynamics on the screening surface. Based on the energy conservation theorem and the characteristics of tobacco screening, a computational model for the air resistance coefficient was derived. KT board specimens were employed as experimental substitutes for tobacco leaves to examine the effects of porosity and geometric dimensions on descent velocity and air resistance. The results indicated that materials with higher porosity exhibited greater descent velocities and lower air resistance, whereas larger geometric dimensions lead to increased aerodynamic drag and higher resistance coefficients. Furthermore, field operational modal analysis revealed that the sieve plate exhibited subharmonic resonances within the 9.9-10 Hz and 20-30 Hz frequency bands under nonlinear excitation. These findings could provide theoretical and data support for structural optimization aimed at noise reduction and screening efficiency enhancement
Estimation of vehicle state based on maximum correntropy square-root cubature Kalman Filter
Full text linkState estimation of a vehicle is an important direction under the research branch of automotive dynamics, with the aim of determining state variables that reflect vehicle handling stability and other characteristics. In order to solve the problem of poor estimation accuracy caused by heavy tailed non Gaussian noise in traditional state estimation methods, a new filtering algorithm based on the Maximum Correlation Entropy criterion (MCC) and the Square-root Cubature Kalman Filter (MCSCKF) is proposed. On the basis of establishing a nonlinear 3-DOF vehicle model, the yaw rate and the side slip angle as well as the longitudinal velocity of the vehicle were estimated. And the effectiveness of the algorithm was verified through joint simulation with Carsim and Matlab/Simulink. The results show that the MCSCKF algorithm can adapt to complex working conditions and has better accuracy in vehicle state estimation than traditional state estimation algorithms. Meanwhile, the MCSCKF algorithm can effectively reduce the impact of heavy tail non Gaussian noise and improve the accuracy of vehicle state estimation
Fabrication and characterization of interdigital transducer structures as temperature sensors by two-photon lithography
Full text linkContinuous developments in the field of 3D printing techniques and equipment have enabled their usage in the field of electronics structures, circuits, and device fabrication in addition to many other fields. This advancement has enabled the potential fabrication of sensors using silicon-based micro or even Nanoelectronics. Currently, the manufacturing and packaging of such devices and structures are heavily reliant on lithography, which can be slow and can involve substantial processing requirements. In this paper, a temperature-sensing Interdigital Transducer (IDT) structure was designed and fabricated using Direct Laser Writing (DLW) based on Two-Photon Lithography (TPL), which is a high-resolution 3D printing technology. The TPL in a positive photoresist was combined with the physical vapor deposition method and the lift-off process to create gold IDT microstructures. The developed sensing structures were characterized using a network analyzer to determine the resonance frequency and its dependence on the temperature changes. The results showed that the IDT structures exhibit a linear response toward the changes in temperature with an average sensitivity of 0.123 MHz/°C. The most important advantage in producing the IDT structure with the additive manufacturing technique is that a very small-sized structure is produced error-free and efficiently
Stress-strain state of a welded high-strength steel pipeline in the presence of surface defects
Full text linkThe construction of main pipelines is now predominantly carried out using high-strength steels. This makes it possible to increase pipeline capacity while maintaining the existing pipe geometry. However, the issue of ensuring the strength of such pipelines in the presence of surface defects is still relevant. This is especially true for pipeline segments that are located in hard-to-reach places, and therefore, it is difficult to repair and restore. At the same time, the introduction of high-strength steels involves a complex system of material alloying and special thermo-mechanical strengthening technologies. As a result, special structures of increased strength can be produced, but they are sensitive to reheating, in particular when welding technologies are used. This is due to the formation of a special zone of thermal deformation influence in the vicinity of the weld. Material properties of the pipes differ from their original characteristics. The stress-strain state is formed, which also affects the strength of the welded pipeline. The nature of the stress-strain state of welded joints of pipes made of high-strength materials differs from the well-studied stress distributions in pipelines built in the past sixty-eighty years of the past century. In particular, several localized maxima of stresses can be located not only on the weld axis but also in the zone of thermal deformation influence. Therefore, it is important to evaluate the effect of weld stresses in welded joints of high-strength steel pipes on the strength of the pipeline in the presence of surface defects. Since the defect may be located at an arbitrary distance from the weld axis, the predicted strength of the welded pipeline segment can vary significantly
Modeling of the transportation process on the Kokand-Andijan section of the Kokand regional railway track junction of the Uzbek railway
Full text linkThe article presents original research results on the substantiation of the forward motion parameters of a freight train with a fixed maximum mass of the train and the main traction and operational characteristics of the energy efficiency of O’z-EL type AC freight electric locomotives on a real flat section of the railway. Energy-optimal control modes for the movement of the aforementioned freight train by electric locomotives of the O’z-EL series have been developed using the original computer hardware and software complex KORTES, and their traction and energy characteristics are presented in the form of numerical values and graphs with an error of no more than five percent compared to the practical data of the Kokand locomotive depot of the Uzbek Railway. The above results will be further used by the authors to evaluate the effectiveness of various options for energy-optimal control modes for the power equipment of the Oʼz-EL series electric locomotives when implementing freight transportation on sections of the Uzbekistan railway industry of varying complexity under real operating conditions
Effect of parametric modulation on the stability of a periodic oscillator: a study with Airy functions
Full text linkThis work investigates the stability of a linear oscillator with a periodically varying stiffness composed of constant and linearly time-dependent segments. By combining Floquet theory with an analytical formulation in terms of Airy functions, the monodromy matrix is obtained in closed form and the characteristic multipliers that determine the stability regime are calculated. Unlike the classical literature on Hill or Mathieu systems, where the stiffness profile is assumed to switch instantaneously or vary sinusoidally, the present model explicitly incorporates finite transition times through linear ramps. This allows us to quantify how the duration of these transitions affects the onset of parametric resonance. The resulting stability map reveals alternating bands of stable and unstable regions reminiscent of Arnold tongues, and shows that the proportion of the cycle spent in the linear-ramp stage plays a decisive role in either promoting or suppressing instability. Overall, the study provides a compact analytical and numerical framework for assessing stability in periodically driven parametric systems of practical relevance in physics and engineering
Advancing product and process innovation through knowledge-sharing networks among European industrial SMEs
Full text linkA methodical approach is created in this study to aid SMEs across Europe (Turkiye, UK, Belgium, Italy) in their product and process development endeavors. Methods and processes that must be followed are examined and streamlined, starting from the point of client contact, and ending with establishment of a pilot production line. This study provides strategies to help technicians and engineers create excellent product designs. Though most of the concepts and methods it will produce are anticipated to be applicable to the design of all types of goods, its primary focus is on the engineering-related aspects of product design. The formulation of problems and the conceptual and embodiment phases of design are the main topics of this work. It will support designers in SMEs with problem identification, explanation, and generation and assessment of solutions. To understand their approach and issues, a thorough search in this field is conducted, along with interviews with multiple SMEs. Additionally, to ascertain the SMEs’ network architecture and how their technical employees interact inside these organizations in a way that supports the creation of new products. This will demonstrate these SMEs' advantages or strengthen their creative positions in the face of global competition
Impact of occlusal trauma on periodontal disease: a literature review
Full text linkPeriodontal disease can be defined as a chronic inflammatory process primarily associated with the accumulation of dental biofilm that affects the supporting periodontal and protective tissues of the periodontium, including root cementum, gingiva, alveolar bone, and periodontal ligament. However, evidence indicates that non-microbial factors, such as occlusal trauma, may also contribute to its progression. In this context, the need to investigate the possible correlation between loss of periodontal attachment and the presence of occlusal alterations, particularly those arising from repetitive traumatic loading, is emphasized. The present study aimed to critically analyze the existing scientific literature on the relationship between occlusal trauma and periodontal impairment. A total of twenty-eight articles were included, selected from the SciELO, PubMed, and Google Scholar databases, published between 1999 and 2025, using terms such as occlusal trauma, periodontal disease, inflammatory mediators, and periodontal inflammation. The qualitative analysis aimed to highlight convergences and divergences in the findings, thereby contributing to a deeper understanding of the factors that influence periodontal disease. The study revealed that, although occlusal trauma is not a causative factor of the disease, it exacerbates the destruction of already compromised tissues, highlighting the need for an integrated therapeutic approach for its management