A subtle review on the challenges of photocatalytic fuel cell for sustainable power production

The revolution in the arena of functional materials for the development of well advanced engineered photocatalyst can efficiently harness photon energy from a wide spectrum of electromagnetic radiation. These next-generation smart materials would be a spectacular approach in designing devices such as photovoltaic cells, photoelectrochemical cells, and photocatalytic fuel cells. Photocatalytic oxidation of water or wastewater for concurrent production of hydrogen and electric current has turned out as a principal concept for the construction of modern photocatalytic fuel cells (PFCs). Such PFCs mimics reverse photosynthesis process where electrical energy is generated from organic pollutants. In recent years many reviews on focusing the design, fabrication, and theoretical efficiency of the PFCs have been published. Hence the present review is aimed to unveil the wall-to-wall information starting from fundamentals spanning to working principles, structural configuration, electrochemical degradation of pollutants and photoelectrochemical properties, electron transport, thermodynamic behavior and columbic efficiency of studied PFCs.     

Nanoindentation and Wear Characteristics of Al 5083/SiC_p Nanocomposites Synthesized by High Energy Ball Milling and Spark Plasma Sintering

Al 5083/10 wt% SiC p nano composites have been synthesized by means of high energy ball milling followed by spark plasma sintering (SPS). Nano composites produced via this method exhibited near-theoretical density while retaining the nano-grained features. X-ray diffraction (XRD) analysis indicated that the crystalline size of the ball milled Al 5083 matrix was observed to be ～25 nm and it was coarsened up to ～30 nm after SPS. Nano indentation results of nano composites demonstrated a high hardness of ～280 HV with an elastic modulus of 126 GPa. Wear and friction characteristics with addition of SiC p reinforcement exhibited significant improvement in terms of coefficient of friction and specific wear rate to that of nano structured Al 5083 alloy. The reduction in specific wear rate in the nanocomposite was mainly due to the change of wear mechanism from adhesive to abrasive wear with the addition of SiC p which resulted in high hardness associated with nano-grained microstructure.     

Development of cerium and silicon co-doped hydroxyapatite nanopowder and its in vitro biological studies for bone regeneration applications

Multi-ion, co-substituted bioactive glass ceramics play a significant role in the stimulation of physical and biological properties for outstanding effects in biomedical application. The following work attempts to develop HAP as a parent material doped with a combination of cerium (Ce⁴⁺ @1.25?wt%) and silicon (Si⁴⁺ @1, 3 and 5?wt%) by refluxing based sol-gel technique. The anti-bacterial tests exhibit E. coli showing higher inhibition efficiency, in vitro hemolytic test exhibit good compatible nature of dual doped HAP with erythrocytes (<5% of hemolytic). In vitro bioactivity assay confirms that the developed dual doped HAP possesses excellent bone-like apatite layer formation on their surfaces. In vitro cellular study was performed for Ce/Si-HAP@5% powder against MG-63 cells, which demonstrated the good cell viability at higher concentrations (up to 800?µg/ml). Further, dual doped HAP powders were characterized by various analytical techniques such as ATR-FTIR, Powder-XRD, TGA-DTA, SEM-EDS, TEM and XPS analysis. The studies confirm that the synthesized dual doped HAP will act as better bioactive glass ceramics for potential orthopedic and dentistry applications.     

Analyzing the characteristics of fuel extracted by catalytic conversion of waste engine oil

Production of hydrocarbon fuel from waste oil such as industrial and engine waste oil is an excellent way for producing alternating fuel sources. The aim of the present study is to obtain diesel-like fuel from waste engine oil (WEO) which can be used as an alternate fuel for compression ignition (CI) engine. With this aim in mind, WEO was purified from contaminants and thermally cracked with two different catalysts such as red mud and fly ash in a catalytic thermal reactor (CTR). The oil product obtained after catalytic conversion using red mud catalyst was named as WEORM and using fly ash catalyst was named as WEOFA. To investigate the influence of these two catalysts with WEO, different properties such as density, kinematic viscosity, calorific value, flash, and fire points were determined. Moreover, the compositional analyses for WEORM and WEOFA were analyzed by Fourier transform infrared (FT-IR) spectroscopy and gas chromatography–mass spectrometry (GC-MS). FT-IR spectroscopy revealed the presence of several bonds which appeared in WEORM and WEOFA were almost identical to the diesel fuel. Further FT-IR results confirmed that most of the hydrocarbons present in WEORM and WEOFA were alkanes. Furthermore, in GC-MS analysis, WEORM and WEOFA were mainly composed of C₁₀–C₃₀ hydrocarbons with the presence of aliphatic hydrocarbons and aromatics. Similar to fossil diesel fuel, they mainly contain paraffins, napthenese, and aromatics. Our results revealed that WEO can be effectively recycled and reused as an alternate source of hydrocarbon energy.     

Metal organic frameworks as electrocatalysts: Hydrogen evolution reactions and overall water splitting

The development of clean energy technologies to protect the environment is an important demand of the times. Electrocatalysis is emerging as a promising method for evolution of hydrogen and overall water splitting. Nowadays, metal organic frameworks (MOFs) have emerged as electrocatalysts having uniformly distributed active sites and high electrical conductivity. This review summarizes the latest advances in heterogeneous catalysis by MOFs and their composite/derivatives for efficient hydrogen evolution reaction (HER) and water splitting. Pristine MOFs with their recent development are summarized first followed by composites of MOFs with their enhanced electrocatalytic performances. Overall water splitting by using bifunctional electrocatalysts derived from MOFs with different synthetic approaches is provided and this review gives the metal-based categorisation of precursor MOFs. Different strategies to improve chemical stability, conductivity, and overall electrocatalytic properties have been discussed. In the last, perspectives on the synthesis of efficient MOF-based electrocatalyst materials are provided.     

Interaction Between Two Mutually Orthogonal Heat-Generating Baffles in a Square Cavity

Laminar free convection induced by two mutually orthogonal discrete heat-generating baffles in a two-dimensional square cavity is analyzed numerically. The computations were carried out for different locations and combinations of heat source strengths of the baffles for a fixed Grashof number of 10⁶and Prandtl number of 0.71. The coupled governing equations were solved bya finite-difference method using alternating direction implicit technique and successive overrelaxation methods. The obtained results clearly show that the hydrodynamic and thermal fields in the cavity depend on both the location and strength of the heat-generating baffles. Though the flow inhibition is caused by both the baffles, the baffle with higher source strength plays a decisive role in inducing the flow. The locations of baffles with unequal source strengths produce significant changes in the net heat transfer rate. This is further magnified for higher contrast in source strengths. This study provides qualitative suggestions that may improve the thermal design of sealed enclosures, which are encountered frequently in the electronics industry.     

Assessing the impact of palmitic,myristic and lauric acids on hydrogen production from glucose fermentation by mixed anaerobic granular cultures

The effects of lauric (LUA), myristic (MA), palmitic (PA), and a mixture of myristic:palmitic (MA:PA) acids on hydrogen (H₂) production from glucose degradation using anaerobic mixed cultures were assessed at 37 °C with an initial pH set at 5.0 and 7.131 mM of each acid. The maximum H₂ yield (2.53 ± 0.18 mol mol⁻¹ glucose) was observed in cultures treated with PA. A principal component analysis (PCA) of the by-products and the microbial population data sets detected similarities between the controls and PA treated cultures; however, differences were observed between the controls and PA treated cultures in comparison to the MA and LUA treated cultures. The flux balance analysis (FBA) showed that PA decreased the quantity of H₂ consumed via homoacetogenesis compared to the other LCFAs. The control culture was dominated by Thermoanaerovibrio acidaminovorans (60%), Geobacillus sp. and Eubacterium sp. (28%), while Clostridium sp. was less than 1%. Treatment with PA, MA, MA:PA, or LUA increased the H₂ producers (Clostridium sp. and Bacillus sp.) population by approximately 48, 67, 86, and 86%, respectively.     

Development and performance analysis of a novel agitated vessel

The objective of the present study was to design, fabricate and evaluate the performance of a novel airi-nducing impeller system with a specially designed air-inducing tube-set. The novel air-inducing impeller system, when attached to a conventional baffled agitated vessel, could convert it into an air-inducing reactor. Water was used as the working fluid and the characteristics of the impeller system such as critical speed, power consumption and gas holdup were investigated by varying the gas free liquid level, orifice immersion depth, bottom clearance and impeller speed. Results showed that this novel air-inducing impeller system induced the air at speeds lower than the critical speeds reported by most of the investigators in the literature.     

Dual crosslinked carboxymethyl sago pulp/pectin hydrogel beads as potential carrier for colon‐targeted drug delivery

Carboxymethyl sago pulp (CMSP)/pectin hydrogel beads were synthesized by calcium crosslinking and further crosslinked by electron beam irradiation to form drug carrier for colon‐targeted drug. Sphere‐shaped CMSP/pectin 15%/5% hydrogel beads is able to stay intact for 24 h in swelling medium at pH 7.4. It shows pH‐sensitive behavior as the swelling degree increases as pH increases. Fourier transform infrared spectroscopy analysis confirmed the absence of chemical interaction between hydrogel beads and diclofenac sodium. Differential scanning calorimetric and X‐ray diffraction studies indicate the amorphous nature of entrapped diclofenac sodium. The drug encapsulation efficiency is up to about 50%. Less than 9% of drug has been released at pH 1.2 and the hydrogel beads sustain the drug release at pH 7.4 over 30 h. This shows the potential of CMSP/pectin hydrogel beads as carrier for colon‐targeted drug. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43416.