Free-standing carbon nanotubes as non-metal electrocatalyst for oxygen evolution reaction in water splitting

Oxygen evolution reaction (OER) has significant impact on the overall electrochemical water splitting. We introduce, for the first time, a facile approach towards the fabrication of versatile electrode composed of free-standing multiwalled carbon nanotubes (MWCNTs) as electrocatalyst for the water splitting reaction. Directly extracted MWCNTs as sheets from vertically grown arrays transferred over the glass substrate, are used without any post treatment as a working electrode for OER. Onset potential of 1.60 V was achieved for MWCNTs which is significantly reduced as compared to platinum based metal electrode (1.72 V) with excellent current density. No surface modification, metal-free nature, flexibility and low cost with excellent catalytic activity proved this material as a promising candidate for the replacement of metal based electrodes in electrochemical water splitting.     

Recommendations for ammonia borane composite pellets as a hydrogen storage medium

The perspective of this study describes a new concept for ammonia borane (NH₃BH₃, AB) in the form of pellet composited with CoB catalyst to use as a hydrogen storage medium. For the purpose of this, hydrogen storage capacity and physical-chemical properties of composite pellet are examined and tested to investigate effects of specified environmental conditions by exposing pellets in temperature from 22 °C to 80 °C in a long period of time (1 day–4 months). A statistical strategy is provided to detail the investigation for significant differences between holding conditions and their interactions. These results suggest that the changing in holding time is more important than the temperature. The general point of view, there is no change in hydrogen storage properties when the composite pellets held at low temperature about 22 °C for 3 months, and the same trend is also preserved when the composites are kept at the higher temperature for a week. It is concluded that the composite pellets shown performance at hydrogen storage with easy handling and controlled hydrogen generation for on-board energy applications.     

Using integrated fuzzy DEMATEL and fuzzy C: means algorithm for supplier evaluation and selection

Decision-making techniques are used to help evaluate the current suppliers’ aim at classifying performance of individual suppliers against desired levels of performance, so as to design suitable plans to increase the performance and capabilities of suppliers. In this study, an integrated model is introduced and proposed for increasing the supplier selection and evaluation quality. The methodology is composed of two steps. The first stage is fuzzy decision-making trial and evaluation laboratory method in which the interactions between the evaluation criteria and the criteria weight have been computed. At the second stage, performances of suppliers are assessed using both the criteria weights obtained at the first stage and fuzzy c-means clustering algorithm by classifying the vendors according to their performances. Obtained results show that the proposed model is very well suited as a decision-making tool for supplier selection decisions.     

Antecedents and consequences of team potency in software development projects

Developing new software quickly, successfully, and at low cost is critical in organizations. Ways of assessing the effectiveness of development teams has highlighted measures of factors, such as teamwork, group cohesiveness, and team integration, but the use of group potency theory (the collective belief of a group that it can be effective) is rare. In our study, we investigated antecedents of and consequences to group potency in software development project teams. By examining 53 software development project teams collected from small and medium-sized software firms in Turkey, we found, that team potency positively affected speed-to-market, development cost, and market success of the product. We also found that trust among project team members, past experiences of the members, and team empowerment had a positive impact on the team potency during the project. Managerial and theoretical implications are discussed.     

Ultrasound- and Microwave-Assisted Extractions Facilitate Oil Recovery from Gilthead Seabream (Sparus aurata) By-Products and Enhance Fish Oil Quality Parameters

This research aimed to analyze ultrasound (UAE) and microwave-assisted extraction (MAE) as novel technologies for utilizing gilthead seabream (Sparus aurata) by-products to produce high-quality fish oil for human consumption. The impacts of extraction parameters, namely, temperature, time, solvent-to-solid ratio, and their interactions on the extraction yield, are investigated using response surface methodology (RSM), and a central composite rotatable design. The optimized conditions are 15.47 mL g⁻¹ of solvent-to-solid ratio, 38 min, and 42 °C for UAE and 15.84 mL g⁻¹ of solvent-to-solid ratio, 18 min, and 40 °C for MAE. Under optimal conditions, the maximum extraction yields are 38.40 and 36.70% (g/g) for UAE and MAE, respectively. Both UAE and MAE have significantly higher mass transfer rates (61.70 and 121.58 g h⁻¹, respectively) than Soxhlet extraction (10.78 g h⁻¹). The fatty acid composition, physicochemical, and oxidation analyses of fish oils confirm the suitability of both UAE and MAE for the recovery of high-quality oils from fish processing by-products. The valorized oils mainly include unsaturated fatty acids (≈75%) and are rich in oleic acid. Furthermore, scanning electron microscopy analysis reveals that the key driving force for fast oil extraction is the structural degradation of fish by-products caused by ultrasound and microwave. Practical Applications: Due to environmental and economic viewpoints, the validation of fish oil from fish industry by-products has become a popular research topic recently. Alternative recovery techniques such as ultrasound- (UAE) and microwave-assisted extraction (MAE) protocols may have additional benefits in producing functional oils. Interactive effects of process parameters determine the success of the extraction technique; therefore optimization is a critical approach when applying the extraction protocols. This study shows that UAE and MAE techniques significantly enhanced oil extraction rate from gilthead seabream (Sparus aurota) by-products at lower temperatures and by using lower amounts of solvent. UVA and MAE increase oxidative stability and do not change the fatty acid composition. Hence, the by-product of the gilthead seabream can be a sustainable and food-grade fish oil source and UAE and MAE can be a good alternative to the conventional (Soxhlet) extraction by providing high yield and quality oil.     

Comprehensive review of solar radiation modeling based on artificial intelligence and optimization techniques: future concerns and considerations

Clean Technologies and Environmental Policy - An alternative energy source such as solar is one of the most important renewable resources. A reliable solar radiation prediction is essential for...