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This paper introduces several new approaches to stiffness calculation of the composite beam with a circular cross-section. The paper poses the problem of calculating the stiffness of the fibre-reinforced winded beam and introduces a new way of stiffness calculation. The novel semi-analytical calculation represents an approach that is less time consuming than conventional calculation methods or FEA methods. The expected application of the new method of calculation is in preliminary design and design calculations.

This work focusses on identifying the optimal stacking sequence for composite tubes in mountain bike frames using a data-driven model combined with evolutionary algorithms. The objective is to find a frame that is sufficiently stiff while meeting the requirements of weight, strength, and minimum tube wall thickness. The decision variables are the ply winding angles and the ply thicknesses of each tube. The study performs designs for two load cases – Starting and Uphill – and explores two types of winding: the gradual winding of individual layers (1ply) and the winding of layers between predefined inner and outer layers with variable thicknesses (TW). Additionally, the design process is applied to frames made of isotropic materials, such as steel, aluminium, and titanium, using the same methodology to allow for comparison of results. The article demonstrates the successful application of this methodology to common sports equipment, suggesting its potential for beneficial use in other common composite frame structures. [ABSTRACT FROM AUTHOR]

Equine melanocytic tumours are of great concern for horse owners, especially those who own grey horses. These tumours can be initially benign but data from literature suggest that all equine melanocytic tumours have a potential to undergo a malignant transformation and even develop distant metastases. This study aimed to diagnose and classify equine melanocytic tumours, assess their prevalence in relation to the horse's coat colour, sex, and age, and evaluate their occurrence sites. Over the period of four years (2020--2023), biopsies and necropsies of 203 horses were performed; melanocytic tumours were diagnosed in 34 cases (16.75%). Based on the morphological features of the neoplastic cells and presence of distant metastases, 3 horses (8.82%) were diagnosed with early-stage melanocytic lesions, 10 (29.41%) with melanocytomas, 4 (11.76%) with low-grade melanoma, 8 (23.53%) with intermediate-grade melanoma, 6 (17.65%) with metastatic melanoma and 3 (8.82%) with high-grade anaplastic melanoma. There was a significantly higher prevalence of the most malignant types of melanocytic tumours (metastatic melanoma, high-grade anaplastic melanoma) in horses over the age of 15 years (70%, P < 0.05). [ABSTRACT FROM AUTHOR]