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Artificial Neural Network-Based Optimisation of Geometric Characteristics in Laser Metal Deposition of TiC/Ti6Al4V

(2025-02) Tlale, T; Mashinini, P; Masina, Bathusile N

Laser metal deposition operates on the principle of layer-by-layer material addition, wherein each layer is formed by overlapping individual single tracks. Consequently, clads formed serve as the fundamental building blocks for this technology. Their quality directly affects the overall build quality, particularly the geometric characteristics, which are also critical to process productivity. In the present work, geometric characteristics of TiC/Ti6Al4V single tracks fabricated via laser metal deposition are optimised. An artificial neural network model was developed to predict the clad width, height, and dilution using processing parameters, laser power, scan speed, and powder feed rate, as model inputs. The Particle Swarm Optimisation algorithm was employed for hyperparameter selection. The hyperparameter-optimised model achieved a mean squared error of 0.00183 and an R2 score of 0.979 during training, and a mean squared error of 0.00709 and an R2 score of 0.887 during testing. Although the small discrepancy between training and testing metrics suggests slight overfitting, likely due to the size of the dataset, the model achieved a mean absolute percentage error of less than 10% during testing. Subsequently, process plots generated by the model predictions were used to identify suitable parameters, and a processing map was developed to highlight the window that achieves suitable dilution (14–24%), defect-free sound bonding, and thick and dense clads.

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A fully satellite-driven workflow for hydrodynamic modeling in data-scarce coastal systems: Integrating ICESat-2, Sentinel-2, SWOT and reanalysis models

(2026-03) Payandeh, AR; Simard, M; Jensen, D; Campbell, AD; Van Deventer, Heidi; Christensen, A

Hydrodynamic models in coastal and estuarine systems are typically constrained by sparse bathymetry, boundary, and validation data, especially in regions where field campaigns are costly or impractical. Here we develop and test a fully satellite- driven framework for hydrodynamic modeling in South Africa’s Langebaan Lagoon without using any local in situ measurements. Bathymetry is derived by training multispectral Sentinel-2 reflectance against ICESat-2 ATL24 photon- derived depths using an XGBoost model optimized with Bayesian search. The final satellite derived bathymetry reproduces independent ATL24 points with RMSE = 0.45 m and R2 = 0.97. This bathymetry was used in a depth-averaged Delft3D Flexible Mesh model driven at the open boundary by TPXO tidal harmonics and by ERA5 winds. We validate modeled water surface elevation against 16 SWOT low- rate (250 m, unsmoothed) passes in 2023. SWOT–model comparisons yield an overall RMSE of 0.11 m and R2 = 0.61, with typical point differences <0.10 m (~5% of the 2 m tidal range), and showed consistent spatial gradients in water level from the offshore boundary, through Saldanha Bay, and into the lagoon. At the offshore boundary, TPXO and SWOT sea surface heights agree closely (R2 = 0.86). A ~26 min phase lag, determined using a lag-correlation analysis, reduces the TPXO–SWOT RMSE from 0.18 m to 0.11 m, indicating that phase differences explain some of the mismatch, with remaining differences likely linked to non- tidal signals. Our results demonstrate that combining passive optical, photon- counting LiDAR, radar interferometry, and global tidal/atmospheric models enables robust, transferrable hydrodynamic modeling in data-scarce coastal systems, offering a cost-effective pathway for monitoring.

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Combination therapies in drug repurposing: Personalized approaches to combatting leukaemia and multiple myeloma

(2025-04) Monchusi, Bernice A; Dube, Phumuzile; Takundwa, Mutsa M; Kenmogne, VL; Malise, T; Thimiri Govindaraj, Deepak B

Despite advances in cancer research, treating malignancies remains challenging due to issues like drug resistance, disease heterogeneity, and the limited efficacy of current therapies, particularly in relapsed or refractory cases. In recent years, several drugs originally approved for non-cancer indications have shown potential in cancer treatment, demonstrating anti-proliferative, anti-metastatic, and immunomodulatory effects. Drug repurposing has shown immense promise due to well-established safety profiles and mechanisms of action of the compounds. However, the implementation is fraught with clinical, logistical, regulatory, and ethical challenges, especially in diseases such as leukaemia and multiple myeloma. This chapter examines the treatment challenges in leukaemia and multiple myeloma, focusing on the role of drug repurposing in addressing therapeutic resistance and disease variability. It highlights the potential of personalized, tailored combination therapies, using repurposed drug components, to offer more effective, targeted, and cost-efficient treatment strategies, overcoming resistance and improving patient outcomes.

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Selection of wear-resistant materials and implementation framework for remanufacturing ground exploring tools (GETs) for coal mining applications: case-study of continuous miner cutter (CMC’s) components

(2025-04) Akintunde, IB; Lindsay, EE; Olakanmi, EO; Matshediso, BI; Motimedi, T; Botes, A; Pityana, Sisa L

Ground exploring tools (GETs), used in coal mining industries, encounter severe failure due to their continuous pressing and scratching against the coal seam embedded with hard bands and impurities. Failure of GETs lead to direct cost expenditure due to replacement of worn-out components; besides, significant indirect cost resulting from machine downtime when they are removed, and new ones are reinstalled. Mining businesses replace worn GETs with new parts at an exorbitant cost at a great risk to their sustainability. Replacement goes against the ethos of the circular economy (CE) philosophy which aims at ensuring highest value of resource utilisation while eliminating waste by improving the design of materials, products, and systems. A critical analysis of the approaches of CE for restoring damaged GETs reveals remanufacturing is the best option to adopt to keep GETs in good working conditions. Meanwhile, there is scanty literature to guide remanufacturing practitioners on materials selection and framework for implementing remanufacturing of damaged GETs. This review addresses this challenge by identifying appropriate wear-resistant materials and the most economically feasible remanufacturing technology which restores the performance of GET’s components to at least as new upon remanufacturing. Using the components of continuous miner (CM) as a case study, the operating environments in which GETs function are described to gain insight into the modes of failure encountered. Information gathered from the operation environments of the GETs and their failure modes assisted in selecting appropriate wear-resistant materials. Techno-economic analysis of the remanufacturing of various modes of failure of the components of GETs was carried out to ascertain the economic feasibility of remanufacturing various failure modes. Future perspectives of failure analysis, material selection, and framework for implementing remanufacturing of various failure modes (based on severity of damage) in GETs are presented. This review extends the frontier of knowledge in the fields of GETs remanufacturing and potential wear-resistant materials for GETs to academic researchers and industrial practitioners.

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Wear and tribo-corrosion behavior of laser surface alloyed Ti6Al4V with Ti, C and Ti + C

(2025-02) Gayen, TK; Akinlabi, E; Pityana, Sisa L; Majumdar, JD

This study concerns evaluation of wear (against WC ball) and tribo-corrosion (against ZrO2 ball in simulated body fluid) properties of alpha + beta titanium alloy (Ti6Al4V) laser surface alloyed with pure titanium (100% Ti), pure carbon (100% C) and a mixture of Ti + C (in the Ti to C ratio of 90:10 and 50:50). The alloyed zone microstructure consists of α and α′ (100% Ti) and TiC and α′ (for 100% C and a mixture of Ti + C). The average microhardness of the surface was found to be improved from 240 VHN for as-received sample to 501 VHN − 630 VHN for laser surface alloyed one and increased with increasing carbon content. The Young’s modulus was found to vary from 132 to 179 GPa as compared to 114 GPa of Ti6Al4V and increased with increase in carbon content. There is a marginal improvement in wear resistance due to laser surface cladding with 100% Ti and a significant improvement due to the addition of carbon. The coefficient of friction (COF) was also marginally reduced due to laser surface processing with 100% Ti and decreased with increasing carbon content. The mechanism wear was established. Tribo-corrosion resistance in fretting wear mode against ZrO2 in Hank’s solution was found to be increased in terms of decrease in tribo-corrosion volume (0.35-0.24 mm3) and COF (0.43-0.29) as compared to as-received Ti6Al4V (0.43 mm3 and 0.52).