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This study examines the impact of the reversing interlock module on the energy intensity of manual wheelchair propulsion while considering the need for the module to cooperate with wheels exhibiting significant roundness deviations. The aim was to determine the additional energy demand caused by the module and analyze the effect of the number of one-sided ribs in flexible rollers on energy consumption. Experiments were conducted on a specially designed test bench to measure the torque, power, and energy required to rotate the wheels. The results show that the use of flexible rollers reduces energy consumption compared to rigid rollers—by 8% at a clamping force of 10 N and by 13% at 100 N. A linear relationship between the clamping force and energy savings, along with a significant influence of the roller rotation direction, was observed. When rotating in the less rigid direction, a 17% reduction in energy intensity was achieved. These findings suggest that incorporating flexible rollers in the reversing interlock module can significantly enhance the energy efficiency of wheelchairs. [ABSTRACT FROM AUTHOR]

The choice of surface finishing technology for floorboards can significantly influence the risk of slipping. This study aimed to assess the impact of surface finishing technology on the likelihood of slippage, focusing on lacquered floorboards made of northern red oak (Quercus rubra L.). Four finishing methods were applied to the floorboard surfaces, with the primary distinction between the tested variants being the level of glossiness in the top layer, ranging from 3 to 20 gloss units (GU). To evaluate slip risk, tests were conducted using the British portable skid resistance tester (BSRT), providing numerical values in the form of the British pendulum number (BPN) and the slip resistance value (SRV) for qualitative comparisons. The analyses revealed that depending on the type of lacquered wood surface layer, the difference in BPN could vary from 46% to 77% for dry tests and from 48% to 60% for wet tests. Matte lacquer finishes, specifically at 19 GU, exhibited the smallest slip risk, while glossy finishes (4 GU) demonstrated the greatest slip risk, especially when the surface was wet. In terms of wet test results, the least slip risk, regardless of wood grain direction, was observed for variant No. 4 (low glossiness at 4 GU), with an SRV value ranging from 51 to 53. Conversely, variant No. 1 (high gloss at a mean of 19 GU) recorded the poorest slip resistance properties, with an SRV between 29 and 31. These findings suggest that matte lacquer finishes generally provide a safer option compared to glossy finishes, and the inclusion of brushing during production can enhance slip resistance. Furthermore, the direction of the wood grain was identified as a contributing factor to slip risk, with a 0° grain orientation presenting the highest risk. These insights can be valuable for flooring manufacturers and installers in selecting and applying finishes that effectively minimize the risk of slipping. These findings can be used by flooring manufacturers and installers to select and apply finishes that minimize slip hazard. [ABSTRACT FROM AUTHOR]

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Using biogas fuel in a modern internal combustion engine equipped with gas equipment of the fourth and fifth generations can create several difficulties. This is due to the low heat of combustion of untreated biogas, the presence of moisture, and the specifics of the injectors. The main problem of the studies we considered is that there are no data on the operating parameters of biogas fuel injectors. Studies on the parameters of the Matrix, Barracuda, Valtek, Hana, and Keihin injectors in relation to biogas fuel were carried out according to performance indicators, the linearity of operation, the resistance of the injectors, the ability to maintain factory parameters, and service life. According to the indicators of performance and linearity of work, Valtek injectors have the highest deviation in productivity and linearity of work, with an average of 38.8%, and the lowest deviation of Barracuda injectors is 7.5%. Keihin (15.3%) and Hana injectors (19.1%) also showed good performance indicators, and therefore can be used effectively for biogas fuel systems. As a result of research on the response time of the injectors, it was established that the best indicators were found for Hana (1.75 ms) and Keihin (1.99 ms) injectors. Valtek injectors showed good response rates (2.07 ms), as did Barracuda injectors (2.19 ms), but the highest response time was found in Matrix injectors, with 2.44 ms. Keihin injectors had the lowest average resistance value of 1.25 ohms, and Valtek injectors had the highest resistance value of 3 ohms. According to the research results, Keihin, Matrix, and Barracuda injectors provide the best ability to maintain factory performance when using biogas fuel at 2 to 5%, and Valtek had the worst performance up to 20%. Keihin, Barracuda, and Hana experimental injectors had the highest service life, which is from 200 to 250 thousand km of car mileage. The lowest indicators were found for Valtek and Matrix injectors, the service life of which varies from 70 to 100 thousand km of mileage. [ABSTRACT FROM AUTHOR]

The air–fuel ratio is a crucial parameter in internal combustion engines that affects optimal engine performance, emissions, fuel efficiency, engine durability, power, and efficiency. Positive pressure ventilators (PPVs) create specific operating conditions for drive units, characterized by a reduced ambient pressure compared to standard atmospheric pressure, which is used to control carburetor-based fuel supply systems. The impact of these conditions was investigated for four commonly used PPVs (with internal combustion engines) in fire services across the European Union (EU), using a lambda (λ), carbon dioxide (CO2), carbon monoxide (CO), and hydrogen carbon (HC) analyser for exhaust gases. All four ventilators were found to operate with lean and very lean mixtures, with their lambda coefficients ranging from 1.6 to 2.2. The conducted tests of the CO2, CO, and HC concentrations in the exhaust gases of all four fans show dependencies consistent with theoretical analyses of the impact of the fuel–air mixture on emissions. It can be observed that as the amount of burned air decreases, the values of CO and HC decrease, while the concentration of CO2 increases with the increase in engine load. Such an operation can accelerate engine wear, increase the emission of harmful exhaust gases, and reduce the effective performance of the device. This condition is attributed to an inadequate design process, where drive units are typically designed to operate within atmospheric pressure conditions, as is common for these engines. However, when operating with a PPV, the fan's rotor induces significant air movement, leading to a reduction in ambient pressure on the intake side where the engine is located, thereby disrupting its proper operation. [ABSTRACT FROM AUTHOR]

Wood choppers shredding branches equipped with low power drive units (up to 10 kW) are characterized by low technical sophistication. Their work translates into the consumption of non-renewable energy sources and the emission of toxic exhaust compounds into the environment. There are innovative technical solutions that allow you to increase the efficiency of chopping machines while reducing environmental impact. Such systems improve the adaptation of chopping machines working conditions to the demand for the branch cutting process. The article characterizes the innovative speed control system of machines loaded periodically variable. The fuel consumption model was presented and referred to the pilot fuel consumption results of a prototype equipped with an adaptive system. Benefits and development directions of the tested systems have been demonstrated.

Experimental research on agricultural tractor movement, acquisition and archiving of kinematic features is an important issue in the analysis of braking and acceleration processes. The obtained traffic parameters depend on the environmental conditions, condition and type of pavement, load, tire pressure and the area of tire-pavement cooperation. The acceleration factor, and in particular the braking process, is determined by the coefficient of friction enabling the assessment of forces and moments acting at the tire-road interface. The kinematic features known as a result of measurements can be used to assess the extent of road safety. The article describes experimental research aimed at understanding the kinematic features of agricultural tractor movement without a trailer on a homogeneous asphalt surface at three pressures in drive tires.

The continuous increase in the use of the transmissions with V-belt, the introduction of new materials for the production of belts and the development of new manufacturing techniques have become the reason for undertaking research works on the possibilities of increasing the load capacity and durability of belts as well as reducing their influence on the environment. It is important to know the latest mechanical and rheological characteristics of the belts in terms of their strength characteristics and fulfilment of the conditions for the correct operation of the transmission. The results of these works will make it possible to determine the scope of applicability of these belts in propulsion and transport technology as well as to develop new geometrical forms of pulleys and V-belts.

Mobile overpressure fans are popular tools used in rescue and extinguishing operations carried out by Fire Protection Units. They are used for exhaust and venting buildings from harmful products of thermal decomposition occurs due to fire. Health and human life may depend on the proper operations of this type of equipment. The aim of the article is to compare the results of real research with numerical analysis. The Scientific and Research Centrum for Fire Protection – National Research Institute test infrastructure was used for research. These test conditions were correlated during CFD (Computional Fluid Dynamics) analysis. The parameters resulting from the operation of the mobile overpressure fan are as follow: the shape of the stream and the distribution of the air flow velocity profile for the distances: 1.5 and 3.0. To perform tests, the representative ventilator was used – being a part of Fire Protection Units equipment. The obtained result provided information on discrepancies in the results of real and simulation studies, indicating further development directions of the research methodology of numerical studies, enabling future support for real studies. The error of the CFD model in relation to the actual tests for measuring the velocity of the flowing air is 0.18 to 18%.

The research aim was to analyse the influence of velocity and size of markers on the accuracy of motion capture measurement utilising image processing with the use of OpenCV. On the basis of the obtained results, the usefulness of the applied measurement method in studying the kinematics of the human body while driving operating a wheelchair was determined. This article presents the test results for a low-budget motion capture measurement system for testing the kinematics of the human body in a single plane. The tested measuring system includes a standard activity camera Xiaomi Yi4K, expanded polystyrene markers with printed ArUco codes, and original software for marker position detection developed by the author. The analysis of the measurement method with regard to its applicability in biomechanical studies has highlighted several key factors: the number of measuring points, measurement accuracy expressed as a relative error and the limit velocity at which the marker trajectory is correctly represented. The article shows that the limit velocity of the marker is 2.2 m/s for 50x50 mm markers and 1.4 m/s for 30x30 mm markers. The number of measured points ranged from 233 to 2,457 depending on the marker velocity. The relative error did not exceed 5% for the marker velocities and thus provided a correct representation of its trajectory.

The particle size distribution of woodworking residues influences the quality of the biofuels made of these materials. Hence, it is essential to investigate the fractional composition of raw materials for pellet production. Tested materials originated from ten parquet manufacturing facilities located in western Poland. The research material consisted of uncontaminated oak (Quercus spp.) wood particles. The tested material had a moisture content ranging from 8.8% to 11.4% and a density of 210.7 ± 1.79 kg/m3. A sieve analysis method segregated the tested material into four distinct size fractions (<1.0 mm, 1.0-2.5 mm, 2.5-5.0 mm, and >5 mm). The average mass shares in these fractions were 53.72 ±0.51%, 35.14 ±0.27%, 9.59 ±0.36%, and 1.55% ±0.11%, respectively. The particle size distributions of wood particles generated in all the facilities demonstrate remarkable similarity. No substantial differences were observed in terms of tilt angle and calorific value. Factors such as variations in raw material species, geographical origins, density, humidity, and technological processes appear to have minimal influence on the sieve-size distributions of the generated sawdust. All these solid wood processing residues can undergo processing into high-quality solid biofuel production. [ABSTRACT FROM AUTHOR]

As part of ongoing research, a wheelchair dynamometer has been designed and built. This device is a complex test stand, enabling research on the operation of wheelchairs, taking into account a number of biomechanical factors in laboratory conditions. Based on a review of the available literature, the braking system was designed and constructed as a part of a dynamometer drive system. This has resulted in a design issue concerning the optimal selection of the electromechanical drive combined with a hydraulic system as the actuator of the brake. The purpose of the research discussed here is to determine the characteristics of the braking system. For this purpose, a series of tests were carried out using a wheelchair with an electric drive, which allowed the generation of a constant rotational speed in the range between 72 rpm and 222 rpm. Based on the test results, the hysteresis of the developed braking system and the characteristics of the braking power were determined. [ABSTRACT FROM AUTHOR]