Nanocrystalline TiO2 coatings were produced on titanium substrates using the plasma electrolytic oxidation technique. The effects of frequency, duty cycle, and type of applied current (pulse and direct) were evaluated on the microstructure of the coatings and the tribological behavior of the samples. Morphological evaluations demonstrated that the pancake structure was developed from coatings created with a unipolar pulsed current. However, a volcano-like surface morphology resulted from a constant current. The XRD analysis results showed that the coatings were composed mainly of the rutile phase by 77.80-96.34 wt. %. In comparison, 22.20 wt. % of the anatase phase was identified in samples produced with direct current. These phases were determined to be nanocrystalline (29.5-48.3 nm), which led to significant improvements in the tribological properties. The sample produced with direct current had larger pores, greater roughness, and a four-times higher thickness than samples created with unipolar current. Furthermore, the tribological study results showed that wear resistance was significantly higher in the unipolar pulsed current coatings than in those obtained with direct current. Moreover, samples made at a higher frequency and lower duty cycle showed better tribological behavior.

The largest proportion of the material used in multistory buildings, and thus its carbon impact, is attributed to their slabs being the main contributor of weight. Because of their high strength and concrete self-weight reduction, composite beams with hollow-core slabs were created for their technical and economic benefits, making this system inexpensive and with a reduced environmental impact, thereby lowering carbon emissions. Geometrically, the hollow slab has a sequence of T and L form pieces on both sides. Hollow slabs are a newer roof feature with a little study undertaken in mechanical characteristics that prove its benefits and downsides in construction. It also has sufficient rigidity. In this work, numerous 19 hollow slabs and flat slabs are modeled using the finite element method, and the findings are compared in terms of hollow slab behavior and economic cost. It demonstrates that reducing the concrete beneath the hollow slab promotes cost-efficiency and the effective use of concrete and steel resources and various approaches for this form of the hollow slab are provided. Implementing a modern double-side beam slab is possible using the presented methods in this paper. It opens a door for creating structures with high stiffness and strength versus vertical and lateral load, along with low material volume.