Mintek

Abstract Organic light-emitting diodes (OLEDs) offer lucrative advantages in screening and illuminating technologies, including high luminance, design flexibility and energy efficiency. However, commercial adoption is hindered by challenges like device degradation and efficiency roll-off, especially under thermal and electrical stress. This review focuses on the application of lanthanide-based materials in OLEDs, emphasizing their unique photophysical properties and roles as emissive dopants and buffer layers. Lanthanide complexes such as europium(III), samarium(III), terbium(III) and cerium(III) possess unique photophysical properties that enhance exciton confinement, reduce polaron–exciton annihilation and improve radiative efficiency. Ligand systems, including β-diketonates, phenanthroline derivatives, scorpionate frameworks and boron-containing ligands, further support high triplet-energy transfer, improved solubility and efficient charge balance within host–dopant architectures. Europium-based emitters demonstrate reduced roll-off and improved luminance. Additionally, cerium(III) complexes show ultrafast excited-state lifetimes and near-unity quantum yields. Metal alloys incorporating ytterbium and its oxides act as superior buffer layers in cathodes that can inhibit the penetration of moisture and oxygen, enhancing both transparency and lifetime. Yb-based cathodes and interlayers, especially in combinations like Yb/Ag or LiF/Yb/Ag, enable efficient electron injection and mitigate degradation through improved stability. These innovations collectively address core issues in OLED performance, laying the foundation for highly durable, high-brightness and flexible optoelectronic devices.

With the continuous consumption of mineral resources, ore grades worldwide are declining, and their increasingly fine-grained, low-grade, mineralogically complex, and highly heterogeneous characteristics have led to a marked rise in the energy consumption and processing costs of mineral separation [...]

High‐entropy alloys (HEAs) represent a new approach in alloy design. Unlike traditional alloys, HEAs are made by combining several main elements in almost equal amounts, which results in unique mechanical and structural properties. One element that has gained a lot of attention for its role in HEAs is niobium (Nb). This is because Nb can enhance the alloy’s resistance to harsh environments, help control its structure and phases, and improve its strength. This review looks closely at how adding Nb to face‐centered cubic (FCC) HEAs affects various properties, such as how the alloy changes phases, its grain structure, strength, and resistance to oxidation and corrosion. It also discusses how different methods of producing these alloys, like vacuum arc melting, powder metallurgy, and 3D printing, can impact their structure and properties. The review further discusses the latest research on modeling HEAs, processing techniques, and the potential uses of Nb‐containing HEAs in different industries.

The precise assessment of phosphorus in geological samples with high titanium levels poses analytical difficulties because of interferences from titanium-rich compositions in the matrix. To precisely quantify phosphorus, this study assesses and optimises several analytical techniques, such as X-ray fluorescence (XRF) and inductively coupled plasma optical emission spectrometry (ICP-OES) after sample preparation by acid digestion (AD), peroxide fusion (PF), pressed pellet (PP), fused bead (FB) and microwave-assisted extraction (MAE). The samples were certified reference materials (CRMs) containing titanium. When combined with a proper sample preparation method such as MAE, ICP-OES showed greater accuracy, whereas XRF scan offered quick, non-destructive analysis but had sensitivity limits. From the 6 methods that were tested, the best recoveries (83.1–100%) of certified values were consistently obtained by MAE/ICP-OES followed by AD/ICP-OES analysis among the studied procedures and FB/XRF (98.3-105%), demonstrating its efficacy in breaking down resistant mineral phases and overcoming matrix interferences. The relative standard deviation (RSD) ranged between 0.25 and 2.1% for MAE/ICP-OES and 0.30 to 5.3% for FB/XRF, indicating good precision. Based on the ANOVA results, the phosphorus concentrations obtained from the different analytical methods showed statistically significant differences across all the CRMs analysed (P<0.05). However, MAE/ICP-OES and FB/XRF proved to not be contributing to the significant difference when assessed using an Honesty Significant Difference (HSD) test. These findings demonstrate that MAE/ICP-OES and FB/XRF methods provide more accurate, precise and repeatable phosphorus quantification in samples rich in titanium. In addition to phosphorus, the samples were also analyzed for associated metal oxides and rare earth elements, which commonly co-occur in high-titanium geological matrices. These determinations were essential to assess matrix interferences and improve the reliability and accuracy of phosphorus quantification methods. • Multiple analytical techniques were compared for phosphorus determination in Ti-rich geological samples. • Microwave-assisted digestion and Fused beads XRF (Rigaku) provided the most reliable phosphorus results. • Fusion with ICP-OES showed high recoveries but potential matrix interferences. • Rare earth elements and metal oxides influenced phosphorus quantification accuracy. • Optimized methods improve analytical reliability in complex geological matrices.

Au- and Ag-nanoparticleswere synthesized and conjugated with fibrinprotein samples through a sodium citrate-induced method for possible‘AuNPs+fibrin’ and ‘AgNPs+fibrin’ coronaformation adsorption studies. Average spherical diameter sizes of11, 18, 45, and 50 nm of Au-nanoparticles and 12, 14, and 26 nm ofAg-nanoparticles were considered for the conjugation process. Thepossible formation of ‘AuNPs+fibrin’ and ‘AgNPS+fibrin’coronas through adsorption of fibrin protein molecules onto Au- andAg-nanoparticles was verified using UV–vis and FTIR spectroscopies,ζ-potential, and TEM imaging. UV–vis red shift was observedon fibrin-conjugated AuNPs+fibrin/AgNPs+fibrin coronas relative tothe unconjugated Au-/Ag-nanoparticles. FTIR spectra provided tracesof possible fibrin functional atoms’ bonding with Au- and Ag-nanoparticlesurface atoms. TEM imaging was also utilized to observe and estimatenanoparticle distribution and sizes. A different nature of conjugationmechanism was noted on Au-/Ag-nanoparticles and fibrin protein molecules.Unconjugated Au-nanoparticles materialize as agglomerates of nanoclusters,while fibrin-conjugated AuNPs+fibrin coronas appear as dispersed individualrandom nanoparticles. On the other hand, unconjugated Ag-nanoparticlesoccur as scattered irregular individual nanoparticles that agglomerateinto AgNPs+fibrin corona nanoclusters upon conjugation with fibrinprotein molecules. Conjugated fibrin proteins do not lose their conformationalstructure or functional property.

In the context of expanding digital education and persistent global disparities in access, this study explores how learning analytics (LA) can enhance teaching effectiveness and student success in open and distance learning (ODeL) environments. Focusing on Mineral Exploitation IA, a first-year engineering module offered in a South African university's Diploma in Mining Engineering program, the study exemplifies the use of data-driven methodologies to address systemic educational challenges such as low pass rates, high dropout rates, and poor learner retention. This case study employs an interdisciplinary and mixed-methods research design, integrating educational data mining (EDM), behavioral analytics, and comparative analysis to assess student engagement, performance, and demographic context. Drawing on data extracted from the institution's Moodle learning management system, the study examines how students interact with online materials (e.g., video content, discussion forums), complete assessments, and vary in performance across geographic and socioeconomic boundaries. Findings reveal that students from remote or under-resourced regions—primarily in developing countries—face significant challenges in accessing digital platforms, often due to infrastructural and technological limitations. These constraints negatively impact their participation and performance, highlighting the interdependence of technological, pedagogical, and socio-economic systems in ODeL contexts. Methodologically, the study aligns with an applied research paradigm, while demonstrating adaptive methodological flexibility. It incorporates a comparative framework that crosses disciplinary boundaries—drawing from education, data science, development studies, and digital communication. In doing so, it situates learning analytics not merely as a technical tool, but as a transdisciplinary research instrument capable of responding to context-specific educational realities. The study recommends targeted pedagogical interventions, including the integration of low-bandwidth, high-accessibility tools such as WhatsApp-based academic support and e-tutoring. These interventions reflect a culturally and technologically responsive design logic, emphasizing methodological pragmatism rooted in lived student experiences. By connecting data-informed research, methodological innovation, and context-sensitive teaching practices, this study contributes to the growing field of transdisciplinary education research. It argues for a shift from content-centred instructional design toward learner-responsive, equity-oriented strategies. It demonstrates how the thoughtful use of learning analytics can foster inclusive and effective online learning environments.

The focus of this study was to determine the feasibility of the integrated process using CaCO 3 and Ca(OH) 2 for removal of Fe 3+ , Al 3+ , and Mn 2+ . Na 2 CO 3 was used for the removal of Ca 2+ as CaCO 3 to avoid fouling of the membranes. Reverse osmosis, electro-dialysis, and freeze crystallization were used for desalination to produce salt Na 2 SO 4 ·10H 2 O/L H 2 O and minimum brine. Fe(OH) 3 , recovered at pH 3.5, was processed to pigment, a salable product. The study was carried out by using a 1 m 3 /h demonstration plant for neutralization and reverse osmosis and information from the literature, and a spreadsheet-based model was developed to determine the feasibility of close to zero waste treatment. The cost of chemical and electrical power amounts R42.39/m 3 feed water (chemical cost was R27.46/m 3 , and power cost was R14.93/m 3 ). The value of pigment, at a price of R20/kg, was R96.78/m 3 feed water. The cost of brine and sludge disposal, after conventional treatment options, will be R433.00/m 3 feed water at a disposal cost of R2,500/t.

The carbonaceous reduction of manganese ore is an energy-intensive process that releases large amounts of pollutant gases. In an attempt to circumvent the greenhouse gas emissions, this research investigates hydrogen as an alternative reductant. The reduction of manganese ore with hydrogen results in the structural changes in the intermediate products, which might limit the diffusion of the reactant gases through the pores. Computational fluid dynamics (CFD) models capture the structural changes and predict the rate controlling mechanism and this is key in designing the prereduction reactors. The current work uses CFD models to predict the degree of reduction in a shaft furnace under hydrogen reducing conditions. Manganese ore is described as a collection of scalar and tensor fields such as thermal conductivity of the porous medium, density, and viscous resistance. The results indicate that advection contributes significantly towards the overall transport of hydrogen to the reaction sites. Porosity of the final product was found to be higher than porosity of the raw material.