An effective polydopamine coating to improve stability and bioactivity of carvacrol-loaded zein nanoparticles

In this study, a simple and facile method was used to fabricate carvacrol-loaded zein nanoparticles (CLZNPs), and CLZNPs were coated with different concentrations (0.25, 0.5 and 1 mg mL⁻¹) of polydopamine (PDA) to fabricate CLZPNPs. Dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analyses showed that CLNPs and CLZPNPs possessed spherical shapes with smooth surfaces in the sizes of 562 and 725 nm and were highly stable possessing high encapsulation efficiency (81.3%). The antioxidant activity of CLZPNPs (ranging from 70.97% to 89.84%) was higher than that (51.42%) of CLZNPs. PDA had a significant effect to increase the antioxidant activity of the CLZNPs. The thermal stability of the particles was influenced by a temperature change from 30 °C to 70 °C. While 1 CLZPNP sample possessed the highest retention rate of carvacrol, the uncoated CLZNPs had the lowest retention value at all temperatures. The antibacterial effect of CLZNPs could be remarkably increased by their coating with PDA at different concentrations (0.25, 0.5 and 1 mg mL⁻¹), reaching the level of 100% inhibition of Salmonella typhimurium, Pseudomonas aeruginosa and Staphylococcus aureus. As a result, coating the carvacrol-loaded nanoparticles (CLZNPs) with PDA enabled us to fabricate highly stable CLZPNPs possessing improved stability and bioactivity. The results of this study suggest that the fabricated nanoformulation would find an application in food packaging technology to increase the storage stability of the products and control various foodborne bacterial pathogens.     

A renewable source based hydrogen energy system for residential applications

In this study, both concentrated solar power and wind energy systems are integrated with electrolyser, fuel cell and absorption cooling subsystems to supply power, cooling, heating and hydrogen to residential applications in an environmentally benign and efficient manner. These subsystems are integrated in a unique way to manage the excess power through water electrolysis to produce and store hydrogen. Integrated systems are thermodynamically analyzed, and their performance is assessed comparatively. Solar radiation intensity, inlet temperature and wind velocity are taken into account, and hence their effects on the system performance are investigated. The results of this study show that the present system appears to be efficient, environmentally friendly and hence sustainable.     

Nanostructured Polyaniline-rGO decorated platinum catalyst with enhanced activity and durability for Methanol oxidation

Addressed herein, a novel composite material is formed between polyaniline and a reduced graphene oxide synthesized by in situ technique in a single step in order to support the platinum nanoparticles. The surface of the reduced graphene oxide layers appeared effectively and stabilized the metal nanoparticles dimensionally. Platinum@reduced graphene oxide-polyaniline (Pt@rGO-PANI) nanoparticles have been characterized by X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. All the results show that Pt@rGO-PANI nanocomposite displayed excellent durability and catalytic activity for the alcohol oxidation reaction. Moreover, the resulting nanocomposite can be used in a variety of carbon-polymer applications, which can be improved and this study provides a powerful and universal synthetic strategy for new polymer-carbon composites in the literature. The methanol oxidation reactions current can reach to 47.2 mA and can maintain 68.4% of the initial value even after 100 cycles.     

Comprehensive investigation of butyl stearate as a multifunctional smart concrete additive for energy‐efficient buildings

Using of phase change materials (PCM) for increasing energy savings in sustainable buildings is receiving a lot of interest in commercial applications. Butyl stearate (BS), as PCM, can be used to maintain ambient temperature in the human comfort zone and prevent temperature fluctuations by enhancing the thermal properties of concrete. The long‐term effects of BS on concrete are not well known. In this study, the applicability of BS, as a smart concrete additive, by direct incorporation in the concrete structure was investigated comprehensively including thermal, rheological, and corrosion behaviour. The thermal characterization of PCM was achieved using DSC, TGA, thermal conductivity, and thermal buffering experiments. Thermal storage capacity of BS was measured to be 134.2 J/g, which is high enough to be used for passive solar energy storage in buildings. The fresh concrete experiments revealed that workability and flowability of fresh concrete mixes were improved. The maximum hydration temperature was reduced, and a retarding effect was observed by the addition of BS. Moreover, the corrosion behaviour of steel embedded in concrete with BS as PCM was studied in a solution of NaCl (3.5 wt%) representing an aggressive environment by utilizing electrochemical impedance spectroscopy (EIS) for long‐term corrosion tests that lasted for 1 year. The open circuit potential of steel in concrete with BS showed noble potential indicating low corrosion probability. The FESEM images and polarization resistance (R_p) values showed that the addition of BS in concrete decreases corrosion of the rebar in comparison with concrete without BS. Addition of BS not only enhances thermal capacity but also exhibits corrosion protection of rebar by hindering penetration of chloride ions into the concrete.     

Maintenance Error Detection Procedure and A Case Study of Failure Analysis Locomotive Diesel Engine Bearings

Journal of Failure Analysis and Prevention - This paper presents a maintenance error detection algorithm. Proposed algorithm is used to determine failure analysis of a locomotive...