A review of prospects and challenges of photocatalytic decomposition of volatile organic compounds (VOCs) under humid environment

Volatile organic compounds (VOCs) are harmful for humans and the surrounding ecosystem. Emissions from these pollutants have caused a significant reduction in air quality, which has an effect on people's health. Alkanes, alkenes, alcohols, aromatics, and other VOC pollutants have all been broken down by TiO₂ photocatalytic processes. Due to several operating inefficiencies and deactivation issues in humid environments, the practical application of photocatalysis has not been realized on a broader scale. The effectiveness of photo-oxidation of VOCs is impacted by a variety of environmental conditions. In the photocatalytic oxidation of the VOCs, relative humidity (RH) is critical. Therefore, it is important to review the recent findings on how humidity affects the photocatalytic breakdown of VOCs in air. To satisfy this need, this work provides a critical review of the related literature with focus on the fundamentals of photocatalysis, photocatalytic degradation of air pollutants, and the influence of humidity on the photocatalytic process degradation for selected air pollutants. It also highlights the kinetic models and typical photocatalytic reactor and supports for VOC removal.     

A novel multicarrier index keying-aided non-orthogonal multiple access systems in presence of uncertain channel state information

This paper investigates the performance of novel multicarrier index keying-aided non-orthogonal multiple access (MCIK-NOMA) system. Unlike the classical scheme, the proposed system sends the information through both index domain and constellation domain symbols thereby increases the spectral efficiency. The impact of channel state information (CSI) uncertainty on the system's performance is investigated. More specifically, the performance of MCIK-NOMA under three different CSI conditions is analyzed: perfect CSI, MMSE-based variable CSI, and fixed CSI uncertainty. This paper also discusses the optimum power difference needed for the successful separation of symbols at the SIC receiver by alternating the power ratio in the proposed system. The influence of selecting different active subcarriers and modulation techniques on the system's performance is studied in detail. The simulation results show that the proposed system achieves better BER and spectral efficiency and outperforms the existing systems.     

The emergence of social dominance in young boys' play groups: Developmental differences and behavior correlates.

This study examined relations among dominance, sociometric preference, and social behavior in groups of 1st- and 3rd-grade boys. 20 groups of 6 unacquainted boys met for 5 45-min semistructured play sessions on consecutive days. Sociometric interviews yielded daily social preference scores. Boys' social behaviors were coded from video records into discrete categories. Dominance hierarchies were formed on the basis of asymmetry (receiving vs initiating) of peer-directed aggression or persuasion attempts. Group-level results indicated that the least coherently organized groups were those containing younger boys and those in which aggression occurred at a high rate. Individual-level results indicated that dominance was associated with social preference to a greater degree among younger than older boys. Dominance was more highly related to leadership in older than younger boys. Implications of these findings are discussed with respect to the role of aggression in the social organization of boys' peer groups. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Synthesis and characterisation of organosoluble polyimides containing the anisyl moiety

A new type of diamine monomer containing the anisyl moiety was synthesized via a straight‐forward one‐step procedure. Anisaldehyde was reacted with 2,6‐dimethylaniline in the presence of dry HCl to attain bis(4‐amino‐3,5‐dimethylphenyl)anisylmethane. A series of organo‐soluble polyimides were prepared using the anisyl diamine and various aromatic dianhydrides via a two step method involving thermal imidization. All polyimides are soluble in strong polar solvents such as N‐methyl‐2‐pyrollidone, N,N‐Dimethylformamide, and N,N‐DimethylAcetamide. The polyimides show excellent thermal stability and good mechanical properties. The glass transition temperatures of the polyimides are in the range 265–294 °C. The tensile strengths are in the range 79–99 MPa and the temperatures at which 10 % weight loss occurs are in the range 460–496 °C. Copyright © 2004 Society of Chemical Industry     

Effect of processing conditions on the oil content of parboiled-rice bran

The oil content of residual milled kernel was consistently lower and of bran higher in parboiled as compared to raw rice at all degrees of milling (d.m.), showing that the rice oil migrated outwards upon parboiling. However, the d.m.-oil content curves for the residual kernel as well as the bran were largely unaffected by varying conditions of parboiling. The total oil content of the grain was also unchanged after parboiling. When the data for the fraction of the total grain oil coming into the bran were plotted against the d.m. for a variety of parboiling conditions, they again fell into a single line. These results showed that, contrary to many earlier claims, the processing condition during parboiling had no effect on the redistribution of the fat in the grain.     

Transient photocurrent response of p-Si/0·5 M H2SO4 interface

An experimental study of the transient photocurrent response of p-Si/0·5 M H₂SO₄ interface is presented. The results have been analysed in terms of a theoretical model wherein surface states are assumed to be present at a discrete levelE _s and communicate exclusively with the semiconductor. The results indicate substantial Fermi level pinning at this interface. Influence of surface oxide films and Pt deposition on the transient response is also discussed.     

Effect of Soluble Solids Concentration and Temperature on Thermo-Physical and Rheological Properties of Mango Puree

Thermo-physical and rheological properties of mango pulp were evaluated at different temperatures (20, 40, 60, and 80°C) and total soluble solids concentrations (15, 20, 32, and 40°Brix). Thermal properties were primarily dependent on the moisture content of the sample, and increased with temperature and decreased with soluble solids concentrations. Density showed a reverse trend. Glass transition temperatures increased with an increase in soluble solids concentrations indicating better stability. Empirical models developed for each thermal property as a function of temperature and soluble solids concentrations (R² > 0.90) generally showed better predictions than published models. Mango puree exhibited pseudo-plastic behavior during steady shear measurements, and the power law model well described their flow behavior. Consistency coefficient increased with soluble solids concentrations and decreased with temperature. The flow behavior index ranged between 0.27 and 0.38 but did not show a clear trend either with soluble solids concentrations or temperature. Small amplitude oscillatory shear measurements revealed that mango puree behaved like a weak gel and demonstrated visco-elastic properties.     

Comparative stability of aspartame and neotame in yoghurt

The comparative stability of aspartame and neotame was monitored in yoghurt during its processing, fermentation and storage. A solid‐phase extraction method was suggest changing it to developed for the isolation of aspartame and neotame. Pasteurisation (85 °C/30 min) resulted in approximately 47% and 3% loss of aspartame and neotame, respectively. During fermentation, 3% loss of aspartame was observed, but no loss of neotame. There was no significant effects on the stability of either aspartame or neotame during storage (4–7 °C/15 days). The results indicated that neotame was more stable than aspartame under both pasteurisation and fermentation conditions; however, during storage, both sweeteners exhibited excellent stability.     

ZnO thin films,surface embedded with biologically derived Ag/Au nanoparticles,for efficient photoelectrochemical splitting of water

ZnO thin films, showing nano-ridges at the surface and the top layer embedded with metal (Ag/Au) nanoparticles (MNP), were obtained by sol-gel synthesis, using zinc acetate dihydrate [(CH₃.COO)₂Zn.2H₂O] as precursor. The method involved prior synthesis of Ag and Au nanoparticles via biological reduction of AgNO₃ and HAuCl₄, respectively, using algae Spirulina platensis. The XRD analysis indicated dominant evolution of wurtzite ZnO phase. Low-angle shift in peaks, seen with nanoparticles embedded films, indicated partial diffusion of metals into ZnO lattice. Band gap energy was least affected and lied in the expected range. AFM and SEM analysis revealed the surface topography and morphology, while EDX analysis confirmed the elemental stoichiometry and existence of Ag/Au nanoparticles in samples. Significant gain in photoelectrochemical current using MNP embedded films is largely accountable to the improvement in electrical conductance and the role played by metal nanoparticles in charge-carrier separation, collection and transport.