Metallurgical and Materials Data

Ageing of Advanced Biomaterials

Rebeka Rudolf, Karlo Raić — Tue, 02 Apr 2024 00:00:00 +0000

The paper presents the ageing processes of advanced biomaterials. The medical profession considers ageing as a syndrome of universal, progressive, irreversible processes that take place at the molecular level (DNA, proteins, lipids) and at the organ level. Ageing is treated quite differently by the engineering profession, which considers it as wear, degradation, corrosion and deformation. In the tissue over time, changes in temperature, changes in pH value and the effect of large forces lead to changes in biomaterials, which are known in the literature as biomaterial ageing processes.

Survey and Challenges of Dental Metallic Materials

Karlo Raic, Rebeka Rudolf, Vojkan Lazić, Peter Majerič — Tue, 02 Apr 2024 00:00:00 +0000

The classification of dental metallic biomaterials is illustrated in depth, with a focus on dental casting alloys. Methods for creating dental prostheses as well as manufacturing shape memory alloys (SMA) Ni-Ti alloys are briefly given. The effect of surface oxide films on metallic biomaterials in the human environment is considered. In order for metal implants to interact with the human body, they need to meet certain requirements.

Nanostructured Materials, Structures and Mechanical Properties, Processing and Applications

Peter Majerič — Tue, 02 Apr 2024 00:00:00 +0000

Nanomaterials are becoming an integral part of high-performance products and services. As technology advances, the possibilities for engineering components with nanomaterials are more numerous, taking advantage of the benefits that these materials have the potential to provide. Nanostructured materials have bulk dimensions with a structure that includes nanoscale features, and have been around for quite some time, hidden in everyday items. More recently, they have been made possible to be analysed and manipulated with increasingly sophisticated instruments and processes. This ability has made them more accessible, however, challenges still remain in the more widespread adoption of these materials for exploiting their advantages. The present paper outlines the position and emergence of nanostructured materials in the broader context of nanomaterials, examining their mechanical properties, production methods and applications.

Nanogold in Rapid Tests

Žiga Jelen — Tue, 02 Apr 2024 00:00:00 +0000

Gold nanoparticles (AuNPs) have been successfully used as biosensors since the early 1990s, when researchers first demonstrated the use of AuNPs functionalized with DNA probes as a sensing platform for the detection of specific DNA sequences. Since then, gold nanoparticle-based biosensors have seen rapid advancements and have been applied in various fields, including medical diagnostics, environmental monitoring, and food safety. Where they are commonly applied as point of care rapid tests based on functionalised AuNPs, for use as highly specific, reliable, and simple to use rapid tests for the determination of pregnancy, diseases, allergies, and many others. This short review article offers a quick insight into the different types of rapid tests and their components.

Nucleation of Topologically Equivalent Phases after Annihilation of Topological Defects

Milan Svetec — Tue, 02 Apr 2024 00:00:00 +0000

The annihilation of radial and hyperbolic point defects within an infinite cylinder of radius R in nematic liquid crystals using Brownian molecular dynamics simulations is studied. Unlike some other studies, where they focus on individual phases of annihilation, this paper considers the entire course of annihilation, both before and after the collision of the two defects. After the collision, merging of defects, and building of a ring disclination structure, the system can experience a structural transition into another topologically equivalent nematic structure, triggered by the nucleation of the ring disclination structure. In the article, the condition under which the transition to the topologically equivalent final structure of the molecular arrangement occurs is quantitatively determined. In addition, a comparison of the temporal evolution of the final stable structure is discussed, where, based on a simple dissipation relation, we obtain an equation that agrees well with the simulation results.

Corrosion Characterisation of Brazing Ag59Cu31Pd10 Alloy for Potential Dental Applications

Stevan Dimitrijević, Silvana Dimitrijević, Renata Kovačević, Marija Korać — Tue, 02 Apr 2024 00:00:00 +0000

This research addresses the corrosion behaviour of the Ag-based alloy with Pd as the component in three different corrosion environments: standard physiological saline solution (SS; 0.9% NaCl), Ringer’s solution (RS), and Fusayama's artificial saliva (AS) at 37 °C. The examination has a primary goal to evaluate the suitability of the alloy as dental material and is used following the electrochemical methods: open circuit potential (OCP), linear polarisation resistance (LRP), and Tafel extrapolation from the potentiodynamic measurement, which is a broad interval of anodic potential. Chemical analysis of the RS after recording a polarisation curve was also a significant part of the study. The results showed OCP values from 35 mV to 65 mV and polarisation resistance values (R_p) in the interval from 8.5 up to 19.3 kΩ×cm². The most corrosive solution was RS, and the least was AS. The corrosion current density in AS was close to 1 μA×cm^-². Although the alloy, in AS particularly, has a relatively high R_p value and OCP close to the Ag alloys with a higher content of noble metals, it has low breakdown potential, which directly led to its classification as an unstable dental material for permanent use. The concentrations of the metals in RS were at ppb levels for Ag, tens of ppb for Pd, and 0.64 mg×dm^-3 for Cu. Regardless of the unsatisfactory corrosion characteristics for the application, the paper showed good potential for the Ag-Cu-Pd system as a brazing filler for dental use and as an adequate control for similar studies.