This paper experimentally reveals some of the resources offered by the instantaneous active electric power in describing the state of three-phase AC induction asynchronous electric motors (with a squirrel-cage rotor) operating under no-load conditions. A mechanical power is required to rotate the rotor with no load, and this mechanical power is satisfactorily reflected in the constant and variable part of instantaneous active electric power. The variable part of this electrical power should necessarily have a periodic component with the same period as the period of rotation of the rotor. This paper proposes a procedure for extracting this periodic component description (as a pattern by means of a selective averaging of instantaneous active electrical power) and analysis. The time origin of this pattern is defined by the time of a selected first passage through the origin of an angular marker placed on the rotor, detectable by a proximity sensor (e.g., a laser sensor). The usefulness of the pattern in describing the state of the motor rotor has been demonstrated by several simple experiments, which show that a slight change in the no-load running conditions of the motor (e.g., by placing a dynamically unbalanced mass on the rotor) has clear effects in changing the shape of the pattern.

The literature and practice have proven the connection between competitiveness at all levels (company, region, national) and its position in international value chains, hence the need to “measure” their economic impact. Traditionally, this has been conducted by using complex quantitative data based on statistical sources translated into input/output tables that are difficult to calculate and interpret and rely on outdated data. While the contribution of clusters as drivers of economic competitiveness has been extensively debated over the last 30 years, it is more recently, after the COVID-19 pandemic, leading to tremendous disruptions in international value chains, that their role of generators and drivers of international value chains has been recognized, proven by the rapid response they have been able to provide in “repairing” the disturbances. The current paper proposes a cluster-based value chain analyses method in which the main measurement unit is the density of the chosen indicator along the value chain links (number of enterprises, turnover, R&D expenditure, exports). The results were checked by classical methods and proven to be congruent. The method allows for a rapid response to sudden disruptions and can be used for both cluster managers as well as economic policymakers at regional and national levels.

Background: Despite the development of manual and passive mechanisms for adjusting prosthesis length, their efficiency remains limited, and users continue to face challenges related to leg length discrepancy (LLD). This dysfunction is an unresolved issue in prosthetics, and the lack of a prosthesis capable of automatically correcting LLD highlights a critical gap in the field. Methods: This study introduces a transtibial self-adaptive prosthesis capable of autonomously compensating for LLD. The prosthesis’s performance was evaluated using the ARAMIS 3D Digital Image Correlation (DIC) system, which monitored the displacement of markers strategically placed on a test mannequin in a strategic manner. Simulated LLDs were generated by inserting standardized plates beneath the mannequin’s intact limb. Results: The proposed prosthesis demonstrated efficient compensation of simulated LLD, with a mean relative error of 8.8% for a 1 mm simulation and 7.2% for a 10 mm simulation. The DIC system highlighted the rapidity and precision of the prosthesis mechanism in adjusting its length to eliminate LLD. Conclusions: The proposed transtibial self-adaptive prosthesis represents a significant advancement in the automatic correction of LLD, enhancing gait symmetry and user stability. The results suggest substantial potential for clinical applications, with promising implications for users of unilateral prostheses.

The energy generated by the impact of vibrations from industrial tools or ongoing activities can be transmitted to humans and cause various injuries. Knitted materials can be considered as parts of anti-vibration equipment as they have proven their ability to absorb shocks. In this study, six spacer knitted fabrics consisting of two outer layers of cotton yarns (Nm 1/50 and Nm 1/40) and cashmere yarns (Nm 2/56) connected by PES monofilaments with a diameter of 0.08 mm were tested. To date, the use of natural yarns in the outer layers of spacer fabrics used in environments subject to vibration has been less studied. The first part of the experiments deals with the measurement of the natural frequencies of the materials, which were determined using the free vibration method. The results show that the direction of the experiment, the yarn count, the stitch density, and the thickness of the material influence the value of the natural frequencies. These values are relevant in order to avoid undesirable resonances that occur when the excitation frequency of an external system overlaps with the natural frequency of the material. In the second part, the vibration transmissibility was simulated using a vibration system with one degree of freedom. The fabrics composed of cotton yarns Nm 1/50 had the highest damping capacity and the highest specific damping coefficient and the lowest value for vibration transmission, which make them recommendable for protective materials.

This paper experimentally reveals some of the resources offered by the evolution of the instantaneous active electric power in describing the state of three-phase AC induction asynchronous electric motors (with squirrel-cage rotor) operating under no-load conditions. A mechanical power is required to rotate the rotor at no-load and this mechanical power is satisfactorily reflected in the constant and variable part of instantaneous active electric power. The variable part of this electrical power should necessarily have a periodic component with the same period as the period of rotation of the rotor. The paper proposes a procedure for extracting this periodic component description (as a pattern, by means of a selective averaging of instantaneous active electrical power) and analysis. The time origin of this pattern is defined by the time of a selected first passage through the origin of an angular marker placed on the rotor, detectable by a proximity sensor (e.g. a laser sensor). The usefulness of the pattern in describing the state of the motor rotor has been demonstrated by several simple experiments which show that a slight change in the no-load running conditions of the motor (e.g. by placing a dynamically unbalanced mass on the rotor) has clear effects in changing the shape of the pattern.

There are numerous methods available for evaluating leg length discrepancy (LLD), ranging from classic clinical techniques to advanced systems based on sophisticated and expensive equipment, as well as rudimentary manual adjustment mechanisms for the prosthesis by specialists. However, unilateral amputee patients often face difficulties in accessing these solutions. They either lack the necessary equipment or do not have a medical specialist available to assist them in preventing postural imbalances. This study proposes the first smartphone-based computer vision system that evaluates and automatically compensates for leg length discrepancy in transtibial prostheses, offering a low-cost, accessible, and fully autonomous alternative to existing solutions. The method was tested using complex metrological systems. The application of the proposed method demonstrated its effectiveness in correcting simulated LLD for various values. Experimental validation demonstrated the system’s ability to restore symmetry in simulated LLD cases within the 1–10 mm range, achieving a relative compensation error of 2.44%. The proposed method for correcting LLD, based on computer vision and integrated into a smartphone, represents a significant advancement in restoring symmetry for unilaterally amputated patients. This technology could provide an accessible, efficient solution, thereby reducing the need for frequent prosthetist visits and enhancing user autonomy.