BIPI

Abstract. Gears are machine parts that generally transmit rotational motions from a power source to at least one executive element. During the transmission process, the gear’s teeth are subjected to high contact pressures and wear, while the gear’s body has to overcome high torsion stresses and eventual chocks. These localized and strongly differentiated loads require highly different properties for the teeth’ surface and the gear’s body. The common practice is to manufacture the gear, including the teeth, from hypoeutectoid alloy steel (typically below 0.2% C) and subject it to a complex thermochemical treatment. The gear is first carburized by exposing the teeth to a carbon-rich environment, such as methane. In this way, the outer layer would become strongly enriched in carbon (exceeding 0.77% C), which would generate cementite, thus significantly enhancing its hardness. The carburized gear is subsequently subjected to a complex heat treatment consisting of solution treatment and tempering. The former would enhance strength, due to the formation of martensite, and the latter would increase toughness and elasticity by transforming the quenching martensite into intermediate compounds such as bainite and troostite. In this way, the outer layer of the teeth would gain hardness by carburizing, thus providing enough resistance to contact pressure and wear. On the other hand, the gear’s body would gain strength and toughness to support high torsional stresses and shocks. After describing this industrial technology, the paper provides an overview of the state of the art of the thermochemical treatment of gears. The most common hypoeutectoid alloy steel grades, used for carburized gears manufacturing, were inventoried. Some experimental results obtained on the carburized, solution-treated and tempered 18CrNiMo7-6 steel were reviewed. Finally, a summary of the most frequently used parameters for carburizing, solution treatment and tempering was performed and some possible new research directions were outlined.
Keywords: Carburizing, solution treatment, tempering, carbides, steel.
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Abstract. In educational institutions, the effectiveness of school management plays a crucial role in organizational performance. This study explores how frequently key managerial behaviors are perceived to occur in a technical high school, based on staff feedback. Using a quantitative approach, a structured questionnaire was administered to 30 respondents, both teachers and administrative staff. The instrument evaluated behaviors such as leadership, communication, fairness, innovation, decision-making, and moral integrity. Results show that while moral integrity, fairness, and communication are generally seen as consistent traits among managers, behaviors like risk-taking and innovation are less frequently observed. Notable differences emerged between perceptions of teaching versus administrative staff, underlining how roles shape expectations. These insights suggest that some areas of leadership are well-developed, while others may benefit from targeted professional development. Overall, the study highlights the need for continuous assessment and feedback to support managerial growth and strengthen leadership practices in schools.
Keywords: management behaviour, leadership, assessment, technical education.
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Abstract. Selective Laser Melting (SLM) enables the fabrication of complex Co–Cr-based alloys with promising applications in biomedical and engineering fields. However, as-built microstructures often present residual stresses and heterogeneities that affect mechanical performance. In this study, Co–Cr–W–Mo–Si alloys were produced by SLM and subjected to various heat treatments in order to evaluate their microhardness response. The results indicate that solution treatments moderately increased hardness, while combined solution and ageing treatments yielded the highest improvements, with average values above 470 Kgf/mm². Nonetheless, heat-treated samples exhibited greater variability, highlighting the importance of optimizing thermal cycles to balance hardness enhancement and microstructural stability.
Keywords: SLM, Co-Cr-W Alloy, Additive Manufacturing, Printing Parameters, Heat treatment.
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Abstract. Magnesium (Mg) alloys have gained significant attention as biodegradable materials for orthopedic applications due to their excellent biocompatibility, mechanical properties like natural bone, and ability to promote bone regeneration. However, their rapid corrosion rate in physiological environments remains a major challenge, which can lead to premature implant failure and unwanted side effects, such as hydrogen gas accumulation.
To address these limitations, researchers have explored various strategies, including alloying with elements like zirconium (Zr), strontium (Sr), and scandium (Sc) to enhance mechanical strength, corrosion resistance, and biological performance. Additionally, surface modifications‒such as polymer and inorganic coatings‒have been employed to slow down degradation and improve the stability of Mg-based implants.
Both in vitro and in vivo studies confirm that Mg alloys exhibit promising osteogenic and angiogenic properties, supporting their potential use in clinical applications. However, differences between laboratory and biological environments require further investigation to optimize degradation rates and ensure safe and effective long-term use. Continued research in alloy development and surface engineering is essential to maximize the benefits of Mg-based biomaterials for bone repair and regeneration.
Keywords: Magnesium alloy, biodegradability, biocompatibility, surface modification, orthopedic implants.
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Abstract. Technological development and our lifestyle of constant stress and ongoing overstimulation have led to an increase and worsening of various psychiatric and psychological disorders in both adults and children. Oral treatment has low tolerability and compliance; it cannot be used in some patient groups and also has numerous side effects.
Textiles for medicine and healthcare have advanced significantly, resulting in notable improvements and innovations. Recent developments in transdermal drug delivery, such as 3D patches, smart patches with various sensors, and absorbable biodegradable patches, highlight the need for ongoing research, particularly in psychiatry, where patients require viable alternatives to oral medications to prevent treatment refusal. This article provides an overview of medical patches, considering the growing trend towards using transdermal patches as an alternative method of administering medication through the skin.
Keywords: Keywords: smart textiles, medical patches, psychiatric disorders, alternative to oral treatment.
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