Phase change materials (PCMs) serve as an efficient thermal energy storage mediums across a range of thermal systems, including solar distillations. The selection of an appropriate PCM candidate is a vital integration aspect that affects solar distillation performance. Therefore, the present research introduces a multi-criteria decision-making (MCDM) framework for identifying suitable PCM candidates for application in solar distillation systems. Evaluation indices include eighteen PCM alternatives and seven criteria, which were established from the literature. Criteria importance through intercriteria correlation (CRITIC) method was used to assign objective weights to the criteria, followed by the MAIRCA (multi-attributive ideal-real comparative analysis) approach to rank PCM alternatives. The proposed MCDM model suggests the suitability of paraffin wax followed by soy wax and beeswax PCMs for solar distillation applications, respectively. The comparative analysis, sensitivity analysis, and Kendall rank correlation effectively validated the rankings, demonstrating a robust positive correlation among the results. This study can serve as a preliminary step for experimental and simulation-based investigations aimed at optimizing the selection of PCM in the early stage, thereby reducing the time and costs associated with further analysis.

A hybrid multicriteria decision-making (MCDM) framework, namely “criteria importance through inter-criteria correlation-combinative distance-based assessment” (CRITIC-CODAS) is introduced to rank automotive brake friction composite materials based on their physical and tribological properties. The ranking analysis was performed on ten brake friction composite material alternatives that contained varying proportions (5% and 10% by weight) of hemp, ramie, pineapple, banana, and Kevlar fibers. The properties of alternatives such as density, porosity, compressibility, friction coefficient, fade-recovery performance, friction fluctuation, cost, and carbon footprint were used as selection criteria. An increase in natural fiber content resulted in a decrease in density, along with an increase in porosity and compressibility. The composite with 5 wt.% Kevlar fiber showed the highest coefficient of friction, while the 5 wt.% ramie fiber-based composites exhibited the lowest levels of fade and friction fluctuations. The wear performance was highest in the composite containing 10 wt.% Kevlar fiber, while the composite with 10 wt.% ramie fiber exhibited the highest recovery. The results indicate that including different fibers in varying amounts can affect the evaluated performance criteria. A hybrid CRITIC-CODAS decision-making technique was used to select the optimal brake friction composite. The findings of this approach revealed that adding 10 wt.% banana fiber to the brake friction composite can give the optimal combination of evaluated properties. A sensitivity analysis was performed on several weight exchange scenarios to see the stability of the ranking results. Using Spearman’s correlation with the ranking outcomes from other MCDM techniques, the suggested decision-making framework was further verified, demonstrating its effectiveness and stability.

In the current work, europium-doped barium titanate particles were used as filler material and polystyrene was used as a matrix to fabricate Ba1−3x/2EuxTiO3/PS polymer nanocomposites with x = 0, 0.005, 0.015 and 0.025. A solid-state reaction was used to synthesize filler particles and the solvent evaporation method was used to form polymer nanocomposites. The effects of ultrasonic treatment were also studied in the formation of nanocomposite materials. The quantitative and qualitative studies were conducted using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), and ultraviolet-visible (UV-Vis) characterization techniques. The XRD data and FTIR data confirm the incorporation of filler particles in the polymer matrix. FE-SEM data confirms that the particles are in the nanophase. The optical band gap was directly affected by the filler particles and it started to reduce as Eu concentration started to increase.