Manganese–Schiff base complex immobilized silica materials for electrocatalytic oxygen reduction

Curtailment of platinum catalysts loading in fuel cell is a recent central issue. As substitutes, these days several organic metal chelate compounds having featured moieties of M–N₄ or M–N₂O₂ (M = transition metal ion) are being used as cathode catalysts in fuel cells. Here, in this study, we report in detail the electrocatalytic activity of manganese–Schiff base complexes for oxygen reduction reaction in 0·05 M HClO₄ at room temperature. Actually, [Mn(salen)]⁺: [N,N′-bis(salicylaldehyde) ethylenediimino manganese(III)]⁺ and [Mn(salophen)]⁺: [N,N′-bis(salicylaldehyde)-1,2-phenylenediimino manganese(III)]⁺ were introduced into/onto the MCM-41 type silica spheres and used for the electrocatalytic reduction of oxygen. Synthesized materials were characterized by UV–Vis, FT–IR and electrochemical techniques. Significant low overpotential for oxygen reduction in 0·05 M HClO₄ on [Mn(salen)]⁺- and [Mn(salophen)]⁺-incorporated silica-modified glassy carbon electrodes was observed.     

Inactivation efficacy of plasma-activated water: influence of plasma treatment time,exposure time and bacterial species

This study aimed to evaluate the influence of plasma treatment time, bacterial exposure time to PAW and bacterial species on the inactivation efficacy of plasma-activated water (PAW), with additional investigation of the inactivation mechanisms of PAW. Six bacterial species, including Listeria innocua, Staphyloccus aureus, Escherichia coli, Pseudomonas fluorescens, Shewanella putrefaciens and Aeromonas hydrophila were selected as the representative bacteria. The initial bacterial concentration was around 7 log CFU ml⁻¹ after mixing with PAW, and the inactivation efficacy was measured after different exposure times during the 4 °C storage. Scanning electron microscopy (SEM) images of the bacteria after PAW treatment were carried out to inspect the cell structure damage, and physicochemical properties of PAW, including pH, conductivity and long-living reactive species of H₂O₂, , and , were examined. The results showed that the inactivation efficacy of PAW was positively correlated with plasma treatment time and bacterial exposure time, and for the species examined in this study, the Gram-negative species were more sensitive to PAW than the Gram-positive species. Cell structure damage, including shrinkage, distortion, or holes, was observed after PAW treatment. The pH of PAW was acidified to 2.5–2.9, and conductivity was significantly increased to 518.0 μs cm⁻¹. and H₂O₂ were reduced during the 48 h storage, while an increased concentration was observed for . This study demonstrated that the processing parameters of plasma treatment time, exposure time and characteristics of bacteria can significantly affect the inactivation efficacy of PAW.     

Dietary exposure assessment of β-glucan in a barley and oat based bread

The objective of this study was to develop a β-glucan human exposure assessment model for a barley and a oat based bread and to compare the resulting exposure to the current FDA recommendation for a health promoting effect (3 g β-glucan/day, 0.75 g/portion of β-glucan). Three formulated barley and oat based breads with 30% (S1), 50% (S2) and 70% (S3) substitution of wheat flour were used in the Monte Carlo simulation model to predict human consumption levels. The level of soluble β-glucan was found to reach 0.77 g/portion for some barley and oat based breads with a substitution level of S3. Under normal consumption patterns, consumption of barley based bread can meet up to 50% of the FDA recommended intake with S1, 70% with S2, and 100% with S3, whereas by consuming an oat based bread the FDA recommended intake is met 30% with S1, 50% with S2 and 70% with S3. The model predicted that total cholesterol (TC) lowered with an increase intake of β-glucan content from ?0.27 to ?0.30 mmol/l and ?0.18 to ?0.29 mmol/l from S1 to S3 for barley and oats based bread, respectively. No significant change was noted for the blood glucose level.     

Thermal performance and embodied energy analysis of a passive house – Case study of vault roof mud-house in India

This paper investigates thermal performance of an existing eco-friendly and low embodied energy vault roof passive house (or mud-house) located at Solar Energy Park of IIT Delhi, New Delhi (India). Based on embodied energy analysis, the energy payback time for the mud-house was determined as 18 years. The embodied energy per unit floor area of R.C.C. building (3702.3 MJ/m²) is quiet high as compared to the mud-house (2298.8 MJ/m²). The mud-house has three rooms with inverted U-shape roof and remaining three rooms with dome shape roof. A thermal model of the house consisting of six interconnected rooms was developed based on energy balance equations which were solved by using fourth order Runge Kutta numerical method. The predicted six room air temperatures were found in good agreement with the experimental observed data on hourly basis in each month for one year. The annual heating and cooling energy saving potential of the mud-house was determined as 1481 kW h/year and 1813 kW h/year respectively for New Delhi composite climate. The total mitigation of CO₂ emissions due to both heating and cooling energy saving potential was determined as 5.2 metric tons/year. The annual carbon credit potential of mud-house was determined as € 52/year. Similar results were obtained for the different climatic locations in India.     

Shear velocity-based uncertainty quantification for rock joint shear strength

Bulletin of Engineering Geology and the Environment - The shear strength of rock joints is an important property required in order to analyze the stability of rock slopes and tunnels. However,...     

Segregation and intermixing in polydisperse liquid–solid fluidized beds: A multifluid model validation study

Multifluid model (MFM) simulations have been carried out on liquid–solid fluidized beds (LSFB) consisting of binary and higher-order polydisperse particle mixtures. The role of particle–particle interactions was found to be as crucial as the drag force under laminar and homogenous LSFB flow regimes. The commonly used particle–particle closure models are designed for turbulent and heterogeneous gas–solid flow regimes and thus exhibit limited to no success when implemented for LSFB operating under laminar and homogenous conditions. A need is perceived to carry out direct numerical simulations of liquid–solid flows and extract data from them to develop rational closure terms to account for the physics of LSFB. Finally, a recommendation flow regime map signifying the performance of the MFM has been proposed. This map will act as a potential guideline to identify whether or not the bed expansion characteristics of a given polydisperse LSFB can be correctly simulated using MFM closures tested.     

Gas permeation in thin films of “high free-volume” glassy perfluoropolymers: Part I. Physical aging

Physical aging of both thick and thin films of “high free-volume” glassy perfluoropolymers was studied by monitoring changes in pure gas permeability of O₂, N₂ and CH₄. All permeability measurements were done at a fixed temperature of 35 °C for more than 1000 h of aging. Two grades of perfluoropolymers, Teflon AF and Hyflon AD, having different comonomer structures but with similar comonomer ratios were studied to understand the effect of comonomer type and content on the aging behavior. The effect of casting process (solution vs. spin coating) and solvent type (vapor pressure and boiling point) had a significant effect on the absolute permeability of both thick and thin films; however, the aging rates were more affected by thickness and solvent type rather than the casting process for similar thicknesses. After 1000 h of aging, the relative permeability for thin films of Teflon AF 2400 was decreased by 27% compared to only 10% for thick films prepared from Novec 7500 solvent. Teflon AF, which has a higher fractional free volume (FFV) than Hyflon AD, is believed to undergo significant aging well before the initial permeability measurement could be made (after ∼ 1 h of aging) and, therefore, Teflon AF materials showed a lower decrease in relative permeability compared to Hyflon AD for the same aging time. The comonomer type and content has a significant effect on the permeability; the initial absolute oxygen permeability for AF 2400 was an order of magnitude higher compared to AD 60. The physical aging of thin films of the various glassy perfluoropolymers was also tracked by recording changes in the refractive index and thickness with time by ellipsometry. The ellipsometry data also confirmed higher aging rates in Hyflon AD compared to Teflon AF materials. The volumetric aging rate, obtained from the change in the refractive index using the Lorentz–Lorenz equation, and the permeability reduction rate from the (P_1000h/P_1h) ratio showed an excellent linear correlation. The (P_1000h/P_1h) ratio also showed a stronger correlation with (T_g−35) °C than with FFV.     

A monolithically integrated high‐efficiency Cu(In,Ga)Se2 mini‐module structured solely by laser

Monolithically integrated Cu(In,Ga)Se₂ mini‐modules were fabricated in order to reduce the width of patterning related dead area. The Cu(In,Ga)Se₂ layers were prepared on soda‐lime glasses using the multistage process at low substrate temperature below 500 °C. A picosecond laser with a wavelength of 532 nm was used for all of the structuring processes (P1, P2, and P3) for the monolithic integration. A “lift‐off” type structuring was applied for P1 and P3, and an “ablation” type was for P2. The laser structuring was optimized to be minimizing the dead area width, and the width of about 70 µm was successfully achieved. A mini‐module, in which the optimized structuring processes were applied for the integration, demonstrated a certified efficiency of 16.6%. Copyright © 2015 John Wiley & Sons, Ltd.     

Effect of glass cover inclination and parametric studies of concentrator-assisted solar distillation system

In this communication, a thermal analysis of concentrator-assisted solar distillation unit has been developed to optimize the glass cover inclination. The thermal energy is based on the energy balance equation for each component of the distillation unit by incorporating the proposed modified Dunckle's relation for internal heat loss. An analytical expression for various parameters, namely the water and glass cover temperatures, hourly and daily yield and an instantaneous thermal efficiency, has been derived. Numerical computations have been carried out and it has been observed that the daily output increases with inclination.     

Synthesis,characterization of β-CD based novel hydrogels with dual objectives of drug release and dye removal

Iranian Polymer Journal - In our recent work, we have reported on hydrogels devoid of cross-linkers. After observing the successful swelling and water retention properties, we have introduced...