A Quest for (sila)0-4cyclopentasilylenes and their Arduengo Analogs by DFT

Silicon - Following our interest in exotic silylenes, here we compare and contrast 20 novel five-membered cyclic silylenes, including saturated (sila)0–4 cyclopentasilylenes (1–10) and...     

Kinetic study of radical polymerization. II. Solid‐state bulk polymerization of sodium methacrylate by differential scanning calorimetry

The solid‐state radical polymerization of sodium methacrylate was investigated. It was initiated by azobisisobutyronitrile, which was used as a radical initiator. Differential scanning calorimetry (DSC) was used to observe the endothermic and exothermic transitions during the polymerization reaction. Structural studies were performed with the DSC thermograms and Fourier transform infrared and ultraviolet–visible spectra, and all of the results confirmed the progress of the reaction. The obtained data revealed that the polymerization reaction proceeded completely with a 100% conversion. ΔH of this reaction was calculated with various amounts of the initiator, and the peak temperatures were determined at different heating rates. The activation energy (19.7 kcal mol^?1) was also obtained by the Kissinger method for this type of solid polymerization reaction. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1648–1654, 2003     

A novel triple notch‐bands ultra wide‐band band‐pass filters using parallel multi‐mode resonators and CSRRs

This article discusses a technique based on combination of multimode resonators (MMR) and complementary split ring resonators (CSRR) to design multi notch‐bands ultra wide‐band (UWB) band‐pass filters (BPF). The proposed structure consists of two parallel multimode resonators, resulting in a dual notch‐band UWB BPF, integrated with a single cell of CSRR to realize the third notch‐band. The mechanism of realizing the notch‐bands is mathematically presented and a triple notch‐bands UWB BPF is designed, simulated and fabricated. The overall size of the proposed filter is reported to be around 36 × 7.7 mm² where a size reduction of around 35% is demonstrated in comparison to the conventional filter. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:375–381, 2014.     

Green synthesis and characterization of RGO/Cu nanocomposites as photocatalytic degradation of organic pollutants in waste-water

Recently, nanocomposite photocatalysts based on semiconductors have attracted much attention due to their suitable bandgap. Combination of tow of several semiconductors can slow down the electron-hole recombination. In this regard, we have depicted an eco-friendly and green fabrication technique to synthesize RGO/Cu nanocomposite by the reduction of graphene oxide and Cu²⁺ ion utilizing spearmint extract as a reductant and capping agent. The sample was identified by FTIR, XRD, FESEM, EDS, HRTEM, and CV. The results of photocatalytic performance revealed that RGO/Cu is an efficient catalyst for degrading organic pollutants. This compound can eliminate Rhodamine B (RhB) and Methylene blue (MB) 91.0% and 72.0%, respectively.     

Zinc oxide nanoparticles: solvent-free synthesis,characterization and application as heterogeneous nanocatalyst for photodegradation of dye from aqueous phase

In present study, for the first time, ZnO nanoparticles have been synthesized via a simple, novel, solvent and template free solid-state thermal decomposition of the mixed Zn(NO₃)·6H₂O and cochineal powders as a novel starting reagent at 600?°C for 3 h. The as-prepared product was analyzed by XRD, EDS, SEM, TEM, FT-IR and DRS. Besides, the effect of cochineal powder on the morphology and particle size of ZnO nanoparticles was investigated. The results exhibited that cochineal powder prevents the sintering of nanoparticles and leads to formation of uniform particles. Moreover, the efficiency of ZnO nanoparticles as a photocatalyst for the decolorization of methylene orange (MO) has been evaluated and 90% degradation of MO was obtained after 120 min.     

Preparation and functional properties of fish gelatin–chitosan blend edible films

With the goal of improving the physico-chemical performance of fish gelatin-based films, composite films were prepared with increasing concentrations of chitosan (Ch) (100G:0Ch, 80G:20Ch, 70G:30Ch, 60G:40Ch and 0G:100Ch, gelatin:Ch), and some of their main physical and functional properties were characterised. The results indicated that the addition of Ch caused significant increase (p < 0.05) in the tensile strength (TS) and elastic modulus, leading to stronger films as compared with gelatin film, but significantly (p < 0.05) decreased the elongation at break. Ch drastically reduced the water vapour permeability (WVP) and solubility of gelatin films, as this decline for the blend film with a 60:40 ratio has been of about 50% (p < 0.05). The light barrier measurements present low values of transparency at 600 nm of the gelatin–chitosan films, indicating that films are very transparent while they have excellent barrier properties against UV light. The structural properties investigated by FTIR and DSC showed a clear interaction between fish gelatin and Ch, forming a new material with enhanced mechanical properties.     

Exterior wood coatings. Part-2: Modeling correlation between coating properties and their weathering performance

Understanding how a coating’s properties are related to its performance characteristics and how measuring its properties can be used for predicting the performance of coating in service was the main focus of this study. A number of exterior penetrating wood stains were characterized in terms of glass transition temperature (T _g), solid content, viscosity, and surface tension. The contact angles of liquid coatings were measured on wood treated with chromated copper arsenate, alkaline copper quat, and copper azole as well as untreated wood. Also, the film thicknesses of the cured coatings on wood surfaces were measured by back-scattered electron imaging of osmium-treated samples. Partial least square-regression (PLS-R) modeling was used to correlate measured coating properties with their weathering performance on the preservative-treated and untreated wood substrates, based on water repellency, color retention, and visual ratings after 3 years of natural weathering. A PLS model was developed with 77% fitting accuracy and 69% prediction ability. This model indicated that preservative treatments significantly affected coating performance, and among coating properties, film thickness, viscosity, and glass transition temperature had the greatest effects on the coatings’ performance in exterior.     

Efficient Synthesis of α-Monoglycerides via Solventless Condensation of Fatty Acids with Glycerol Carbonate

Highly pure α-monoglycerides (5a–e) were successfully prepared in high yields by the condensation of fatty acids such as lauric, myristic, palmitic, stearic and oleic (2a–e) with glycerol carbonate (4-hydroxymethyl-1,3-dioxolan-2-one) (1) in the presence of triethylamine as catalyst. Reaction conditions and spectroscopic identification of products will be presented in this article.