ELECTROMAGNETIC ENHANCEMENT OF CHEMICAL REACTIONS (Devolatilization of Char and Coal)

Abstract

Char in the microwave energy field may enhance chemical reactions by three different ways as described below: (1) directly react with elements in molecules when contacted, (2) create free radicals when the gas molecules contact char,and (3) provide heat to adjacent solid particles. To understand the interactions between char and microwave energy, we first investigated the microwave energy absorption by char and also by the mixture of char and coal at various apparent bed temperatures and various ratios of coal to char in the mixture.

The experimental results clearly demonstrated that pyrolysis products are excellent absorbents of the microwave energy. To enhance the pyrolysis rate of coal with the microwave energy, it was necessary to add char that increased energy absorption rate. Coal/char mixture pyrolysis started immediately when the microwave energy was applied. Also, microwave energy absorption rate increased to 73% of input power. When coal concentration in the coal/char mixture exceeded 50%, energy absorption rate decreased to 54% of input power. Without char, coal was not pyrolyzed with the microwave energy (550 W) applied for 60 minutes.     

High current superconductors for DEMO

In the assumption that DEMO will be an inductively driven tokamak, the number of load cycles will be in the range of several hundred thousands. The requirements for a new generation of Nb₃Sn based high current conductors for DEMO are drafted starting from the output of system code PROCESS. The key objectives include the stability of the DC performance over the lifetime of the machine and the effective use of the Nb₃Sn strand properties, for cost and reliability reasons. A preliminary layout of the winding pack and conductors for the toroidal field magnets is presented. To suppress the mechanism of reversible and irreversible degradation, i.e. to preserve in the cabled conductor the high critical current density of the strand, the thermal strain must be insignificant and no space for micro-bending under transverse load must be left in the strand bundle. The “react-and-wind” method is preferred here, with a graded, layer wound magnet, containing both Nb₃Sn and NbTi layers. The implications of the conductor choice on the coil design and technology are highlighted. A roadmap is sketched for the development of a full size prototype conductor sample and demonstration of the key technologies.     

Information and data quality in business networking: a key concept for enterprises in its early stages of development

Information and data of high quality are critical for successful business performance in general and Business Networking in particular. As the trend toward sharing information between business partners and value networks is still increasing, the position paper aims at providing a comprehensive perspective on the state of research with regard to information and data quality in Business Networking. The paper shows that much has been achieved, but that fundamental aspects still remain unaddressed. Based on the results of a literature review, the paper identifies consequential areas of research and makes six propositions for future research. In doing so, the position paper aims at offering novel perspectives and at introducing new areas of research in a field of particularly high relevance in the networked business and electronic markets domain.     

Electrochemically deposited polyethyleneimine films and their characterization

Polyethyleneimine films have been deposited on platinum electrode surfaces by electrochemical oxidation of ethylenediamine H₂N–CH₂–CH₂–NH₂ (EDA) in acetonitrile solutions. This electrochemical synthesis was realized by cyclic voltammetry and gravimetry techniques. Then, the characterization of the thin solid polyethyleneimine film was performed using X-ray photoelectron spectroscopy and infrared spectroscopy. It was also shown, using atomic force microscopy, that the solid polymeric coating has a granular and homogeneous structure. The influence of EDA concentration on the electropolymerization process was studied leading to the conclusion that the reaction is easier for high EDA concentration. Then, the influence of the nature and concentration of the supporting salt was investigated, showing that its nature is not very important, contrary to its concentration.     

Towards the integration of dark- and photo-fermentative waste treatment. 3. Potato as substrate for sequential dark fermentation and light-driven H2 production

The goal of the study was to characterize H₂ production in an integrated process utilizing potato homogenate (PH) for dark, fermentative H₂ production followed by H₂ photoproduction using purple non-sulfur bacteria. Emphasis was placed on (a) examining potato fermentation effluent (FE) as substrate for H₂ photoproduction, (b) estimating the yield and efficiency of both processes, and (c) elucidating the physiological factors influencing the integrated system as a whole. In the dark stage maximal production of gas (11.5 L L⁻¹ of the culture) and VFA (350 mM) were observed with a PH concentration of 400 g L⁻¹ of medium, but higher yields (0.05 L g⁻¹ PH; 1.9 mmol g⁻¹ PH) were obtained at PH concentrations of 50–100 g L⁻¹. H₂ photoproduction by purple bacteria was inhibited at high FE content. Upon suitable dilution, adequate illumination, and supplementation with Fe/Mg/phosphate nutrients, H₂ photoproduction reached 40 L L⁻¹ of non-diluted FE, with a total H₂ yield of 5.6 mol mol⁻¹ glucose equivalent for the two-stage integrated process.     

Preparing Microcomposite Powders Doped with Antimony Dioxide and Properties of Thick Films Based on Those Powders

The goal of the work reported here was to develop a method of applying glass nanolayers of variable thickness to Sn_0.9Sb_0.1O₂ particles and to investigate how this affects the electrical properties of thick-film resistors. We prepared Sn_0.9Sb_0.1O₂ powders by calcinating coprecipitated tin and antimony hydroxides. Thin layers of aluminum, barium, and boron compounds were then precipitated from aqueous solutions onto powder particles. Nanolayers of glass in the BaO ― Al₂O₃ ― B₂O₃ system were obtained by dissolution followed by heat treatment. Resistive thick films made from such microcomposite powders have a higher resistivity than do those prepared by traditional methods and that resistivity changes little after repeated heat treatments. The thermal coefficient of electrical resistance decreases with increasing thickness of the glassy layer on the surface of the conducting particles.     

Supramolecular Nanofibers Self-Assembled from Foldamers: Structure Control through Preassembly

We used a helical polymer backbone (polyacrylamide) as a scaffold to organize perylene diimide chromophores into well-defined foldamers, which further undergo self-assembly into supramolecular tube-like arrays in aqueous media, as revealed by cryo-TEM imaging. The arrays are supramolecular polymers, whose structure is templated by folded primary building blocks, representing a useful tool for directing self-assembly . Exciton migration in the supramolecular arrays was studied by transient absorption and revealed a moderate exciton diffusion propensity.     

Non‐ionic Dendronized Multiamphiphilic Polymers as Nanocarriers for Biomedical Applications

A new class of non‐ionic dendronized multiamphiphilic polymers is prepared from a biodegradable (AB)_n‐type diblock polymer synthesized from 2‐azido‐1,3‐propanediol (azido glycerol) and polyethylene glycol (PEG)‐600 diethylester using Novozym‐435 (Candida antarctica lipase) as a biocatalyst, following a well‐established biocatalytic route. These polymers are functionalized with dendritic polyglycerols (G1 and G2) and octadecyl chains in different functionalization levels via click chemistry to generate dendronized multiamphiphilic polymers. Surface tension measurements and dynamic light scattering studies reveal that all of the multiamphiphilic polymers spontaneously self‐assemble in aqueous solution. Cryogenic transmission electron microscopy further proves the formation of multiamphiphiles towards monodisperse spherical micelles of about 7–9 nm in diameter. The evidence from UV–vis and fluorescence spectroscopy suggests the effective solubilization of hydrophobic guests like pyrene and 1‐anilinonaphthalene‐8‐sulfonic acid within the hydrophobic core of the micelles. These results demonstrate the potential of these dendronized multiamphiphilic polymers for the development of prospective drug delivery systems for the solubilization of poorly water soluble drugs.     

Towards the integration of dark- and photo-fermentative waste treatment. 4. Repeated batch sequential dark- and photofermentation using starch as substrate

In this study we demonstrated the technical feasibility of a prolonged, sequential two-stage integrated process under a repeated batch mode of starch fermentation. In this durable scheme, the photobioreactor with purple bacteria in the second stage was fed directly with dark culture from the first stage without centrifugation, filtration, or sterilization (not demonstrated previously). After preliminary optimization, both the dark- and the photo-stages were performed under repeated batch modes with different process parameters. Continuous H₂ production in this system was observed at a H₂ yield of up to 1.4 and 3.9 mole mole⁻¹ hexose during the dark- and photo-stage, respectively (for a total of 5.3 mole mole⁻¹ hexose), and rates of 0.9 and 0.5 L L⁻¹ d⁻¹, respectively. Prolonged repeated batch H₂ production was maintained for up to 90 days in each stage and was rather stable under non-aseptic conditions. Potential for improvements in these results are discussed.