Evaluation of adsorption of cationic dyes on H-LTL and K-LTL zeolite

This article investigated adsorption of acridine hydrochloride (Ac) and acriflavine hydrochloride (AF) on zeolite L (in form of K-LTL and H-LTL) including ice hockey and round shapes in order to explore new antenna materials. The amount of the adsorbed dyes and the interactions between the dyes and zeolite framework were examined by the adsorption isotherms study. The study revealed that the adsorption isotherms are fit very well with the Langmuir model. Moreover, the thermodynamic quantities indicated that the adsorptions of both dyes on zeolite L are spontaneous, endothermic and highly disordered. The maximum loading (Θ_max) of AF and Ac on H-LTL and K-LTL with both shapes was in the range of 4.03–6.44 and 0.45–2.80 % by mole, respectively. The higher maximum loading of AF than that of Ac on zeolite L was explained in terms of the stronger interaction of AF with zeolite L than Ac. The morphology of zeolite L was found to have an effect on the adsorption of Ac and AF.     

Effect of drying and proline addition on aroma volatile compounds of acid‐hydrolysed rice bran protein concentrate

Rice bran protein concentrate (RBPc) was hydrolysed by 0.5 N aqueous HCl at 95 °C for 12 h. The liquid hydrolysate obtained was prepared as hydrolysate powder by spray drying. Aroma volatile compounds in liquid hydrolysate and its hydrolysate powder were tentatively identified by GC‐MS. Furfural and vanillin were found in both hydrolysates with high concentration, and vanillin showed the highest odour activity value. Hexanal was present in only liquid hydrolysate. Concentrations of carboxylic acids and heterocyclic compounds, especially 2‐methoxy‐6‐methylpyrazine, increased after drying. Amino acid composition of the hydrolysate powder showed high aspartic acid and glutamic acid. Aroma volatile compounds of hydrolysate powder prepared by the addition of proline at pH 6.0 (Pro6.0‐H) and pH 7.5 (Pro7.5‐H) before drying were investigated. Furaneol was found only in Pro6.0‐H, but it was not detected in Pro7.5‐H and hydrolysate powder without proline addition. Pro7.5‐H had higher furfural and vanillin concentrations than Pro6.0‐H.     

Thermal and acid treatment on natural raw diatomite influencing in synthesis of sodium zeolites

A natural raw diatomite and four modified diatomites by calcination and acidification were used as starting materials for the sodium zeolitization process. Iron impurity content present in the natural raw diatomite which was expressed as Fe₂O₃ is about 5.8% and Q⁴ ([Si(OSi)₄]) unit 64%, whereas the modified diatomite which was treated with hot 6 M H₂SO₄ (refluxed at 100 °C) for 24 h and followed with calcination at 1100 °C for 5 h, contains about 0.5% of Fe₂O₃ and 97% of Q⁴. The results showed that under the studied conditions (NaOH 10–30%w/v, 100–180 °C, solid:liquid 1:10 and 1:30, reaction time 24–180 h) only Na-P1, analcime, cancrinite and hydroxysodalite were obtained and the highest yield of each sodium zeolite product was obtained from the modified diatomite treated with hot H₂SO₄ and followed with calcinations at 1100 °C. This results from the reduction of iron content by acid leaching and the elimination of silanol groups after calcination to form more siloxane groups in the structure of starting materials. In addition, a role of iron content was found to be significant in zeolite formation compared to a role of Q⁴ sites. It was found that a percentage of crystallinity is very high in the case of all starting materials, which first underwent iron impurity elimination before further thermal treatments.     

Multi step energy transfer between three Si_LTL and SiGe_LTL zeolite-loaded dyes

We report a novel potential light-harvesting antenna material constructed with three dyes loaded on two types of zeolite LTL (SiGe_LTL and Si_LTL). Fluorescence resonance energy transfer (FRET) occurs from acridine hydrochloride (Ac) to Thionine acetate (Th) via Acriflavine hydrochloride (AF), which acts as an antenna to receive and transfer energy from Ac to Th. We compared multistep FRET systems based on dye-loaded SiGe_LTL paired with an Si_LTL-based system. Our results show that in both cases, FRET efficiency increases with Th loading and decreases with increasing AF loading. Moreover, the zeolite LTL microenvironment causes a red shift in the fluorescence spectra of the three SiGe_LTL-loaded-dyes compared to those of the Si_LTL-based dyes.     

On-demand waypoints for live P2P video broadcasting

A peer-to-peer architecture has emerged as a promising approach to enabling the ubiquitous deployment of live video broadcasting on the Internet. However the performance in these architectures is unpredictable and fundamentally constrained by the characteristics of the members participating in the broadcast. By characteristics, we refer to user dynamics, out-going bandwidth connectivity, whether the member is behind NAT/firewall, and the network conditions among participating members. While several researchers have looked at hybrid P2P/CDN approaches to address these issues, such approaches require provisioning of centralized server resources prior to a broadcast, which complicates the goal of ubiquitous video broadcasting. In this paper, we explore an alternative architecture where users are willing to donate their bandwidth resources to a broadcast event, even though they are not a participant in the event. Such users constitute what we term a waypoint community. Any given broadcast event involves constructing overlays only based on participants to the extent possible, however waypoints may be dynamically invoked in an on-demand, performance-driven fashion to improve the performance of a broadcast. We present the design of a system built on this idea. Detailed results from trace-driven experiments over the PlanetLab distributed infrastructure and Emulab demonstrate the potential of the waypoint architecture to improve the performance of purely P2P-based overlays.