Behaviour of Coal associated Minerals during Coking and Blast Furnace Processes – a Review

Metallurgical coke is made from a mix of several types of coal that contain various minerals, including quartz, carbonates, feldspars, sulphides and a number of phyllosilicates, represented by clay minerals and micas. During coking and coke consumption processes the minerals undergo various physical and chemical changes, which in the case of coke oven batteries include desulphurization, decarbonation, dehydration, dehydroxylation, polymorph transformations, melting with the formation of an alkali and silica‐rich liquid, and transformation to another crystalline phase. The typical modifications of mineral phases in a blast furnace (BF) coke are polymorph transformations, melting, and the formation of another crystalline phase. These events are also preceded by notable changes in the shape of crystalline aggregates. All these changes affect the coke properties and the processes occurring in a BF. Mineralogical data can help us to better understand the processes taking place in coke batteries and in a BF, and to improve the quality of a coke by more careful selection of coal blends and setting optimal temperatures for its pre‐heating. The degradation of a BF coke by alkalis can be reduced by the addition of certain minerals to the feed coke before charging into the BF.     

Key role of the desolvation in the achievement of the quasi-metallic state of electronically conducting polymers

Redox transformation of electronically conducting polymers was studied by different in situ combined electrochemical techniques. Results obtained with polypyrrole/dodecyl sulfate film in aqueous solution and with polythiophene/hexafluorophosphate films in acetonitrile by in situ ac conductance and EQCM support the assumption of the key role of the desolvation in the achievement of the so-called quasi-metallic state of electronically conducting polymers. The desolvation considered as a phase transition is the chemical background of the capacitive behaviour, and it causes the structural changes, which lead to a film in which the interchain interactions may form the large-scale conducting polymer matrix.     

Film formation and surface properties of enzymatically crosslinked casein films

The use of renewable materials as barrier material is currently intensively investigated. Biopolymers such as polysaccharides, lipids, and proteins have been studied as barrier materials. Protein‐based films often possess good gas barrier properties, but because of their hydrophilic nature the gas barrier properties are sensitive to humidity. The improvement of the properties of sodium caseinate barrier films in potential packaging applications was studied by investigating the effects of enzymatic treatment and plasticizer on the film properties. Oxidoreductases Trametes hirsuta laccase (ThL) and Trichoderma reesei tyrosinase (TrTyr) were compared with transglutaminase for crosslinking of the sodium caseinate molecules in the films and coatings. All of the studied enzymes were able to crosslink sodium caseinate. Film solubility tests, protein electrophoresis, contact angle measurements, and atomic force microscopy studies showed that TrTyr treatment results in sodium caseinate films and coatings with better overall properties compared to treatment with ThL. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Surface properties and moisture behaviour of pine and heat-treated spruce modified with alkoxysilanes by sol–gel process

The surface morphology and moisture behaviour of pine (Pinus sylvestris) sapwood and heat-treated spruce (Picea abies) deposited with two types of silane-based sol–gel coatings were studied by atomic force microscopy (AFM) and water contact angle measurement. The chemical composition and distribution of sol–gel coatings on wood surfaces were investigated by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The AFM images revealed that the sol–gel coatings applied by spreading covered the fine structure of the wood substrates. The surface roughness analysis of the AFM topographical images indicated that the sol–gel coatings, especially the one with short aliphatic chain, had a tendency to smooth the wood surface. The XPS results confirmed that the sol–gel coatings had successfully deposited onto pine sapwood and heat-treated spruce changing their surface chemistries. ToF-SIMS images showing Si ion distribution on treated surfaces revealed that the coatings fully covered pine sapwood surfaces. The thin coating layers formed on heat-treated spruce surfaces followed the original wood surface structure. The contact angle measurements indicated that the water repellent properties of both pine and heat-treated spruce were improved to certain extent by the sol–gel coatings.     

From acacia honey monosaccharide content to a new external binary plasticizer applicable in aqueous whey protein films

Plasticizer is an essential adjuvant in food and pharmaceutical film coatings affecting the appearance, mechanical and permeation properties of the final coat. In the present study, film formation and plasticization of native whey proteins (potential future “green” coating agents for pharmaceuticals and food products), were studied with free isolated films. Special attention was paid to the effects of plasticizer, preheating and film forming solution pH on the mechanical stress–strain and moisture permeation properties of whey protein films. Glycerol, binary mixtures of fructose and glucose, and non-crystalline acacia honey were studied as external plasticizers. The type and amount of plasticizer affected the mechanical stress–strain properties of the whey protein films. A short preheating treatment of whey proteins prior to film casting resulted in mechanically strong films with a reduced elongation. The film forming properties of aqueous whey proteins could be modified by adjusting the pH above the isoelectric point of β-lactoglobulin prior to film coating. For effective plasticization, whey protein films required a high amount of monosaccharide containing plasticizer ranging from 80% to 120% (calculated from the protein weight). A new external binary plasticizer having the same ratio of monosaccharides as non-crystalline acacia honey (fructose and glucose 1.67:1) was found to be applicable in aqueous whey protein films.     

Breath figure templated semifluorinated block copolymers with tunable surface properties and binding capabilities

Patterning of functionalized polymeric surfaces enables the adjustment of their characteristics and use in novel applications. We prepared breath figure (BF) films from three semifluorinated diblock copolymers, which all are composed of a polystyrene block and a semifluorinated one to compare their surface properties. “Click” chemistry was employed to one of the polymers, containing a poly(pentafluorostyrene) block to incorporate hydrophilic sugar or carboxylic acid moieties. The structure of the polymer alters the obtained porous morphology of the films. Contact angle (CA) analyses of the BF films reveals that the surface porosity increases water CAs compared with solvent cast films, and, in the case of hydrophobic polymers, leads to significant increase in the CAs of dodecane. The hydrophobicity of the BF films is further amplified by the removal of the topmost layer which leads in some cases to superhydrophobic surfaces. BF films containing glucose units are hydrophilic exhibiting water CAs below 90°. These glycosylated porous surfaces are shown to bind lectin Con A‐FITC or can be labelled with isothiocyanate marker. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41225.     

Sulphur poisoning of nickel-based hot gas cleaning catalysts in synthetic gasification gas: I. Effect of different process parameters

The effect of different process parameters on sulphur poisoning of nickel catalysts in tar (toluene), ammonia and methane decomposition was studied. Tests were carried out in a fixed-bed tube reactor at 800–1000°C at 5 and under 20 bar total pressure using a synthetic gasification gas mixture. In the same conditions, sulphur affected less the toluene and methane decomposing activity than the ammonia decomposing activity. Ammonia conversion was affected by the catalyst type but not by the nickel content of catalyst. When temperature was increased the effect of sulphur poisoning was decreased. At 20 bar pressure the poisoning effect of sulphur was stronger than at 5 bar pressure. To prevent sulphur poisoning of nickel catalysts in the tar and ammonia decomposition process at high pressure (20–30 bar), the catalyst process should operate at > 900°C. In addition, by decreasing the space velocity of the process the sulphur poisoning effect could be compensated in the test conditions.     

Particle packing simulations based on Newtonian mechanics

A program to simulate the packing of round particles was made in the course of this work. The theoretical packing of the particles was studied in 3-dimensional situations with the program. The effects of friction, elasticity, size and spring co-efficient on packing were examined. It was observed that increased friction caused decreased packing density. Elasticity had a minor effect on the density, while the spring constant defining the interactions between particles had a minimal effect.     

Baseband Digital Predistorter with Quadrature Error Correction

In this article simulation and measurement results of a FPGA implementation of a baseband digital complex gain predistorter with a quadrature modulator and demodulation error correction circuits are presented. Four different methods for finding the quadrature error correction values are compared and the effect of quadrature errors to predistortion is discussed. A 50 dB three stage power amplifier chain with an analog quadrature modulator and demodulator was used in the measurements as the device to be predistorted. The signal used in the measurements and simulations was a 30 dBm 18 kHz 16-QAM signal at 400 MHz carrier frequency. In the measurements 15 dB reduction in 3rd order nonlinearity was achieved. The usage of quadrature error correction reduced the adjacent channel power by 9 dB. Ilari Teikari was born in Tampere, Finland, in 1978. He received the M.Sc. (tech.) degree from Helsinki University of Technology (HUT), Helsinki, Finland, in 2002. He is currently working toward D.Sc. (tech) degree in the electronic circuit design laboratory, HUT. His current research intrests are in the area of power amplifier linearization methods and digital circuit design. Jouko Vankka was born in Helsinki, Finland, in 1965. He received the M.S. and Ph.D. degrees in electrical engineering from Helsinki University of Technology (HUT) in 1991 and 2000, respectively. Since 1995, he has been with the Electronic Circuit Design Laboratory, HUT. His research interests include VLSI architectures and mixed-signal integrated circuits for communication applications. Kari A. I. Halonen was born in Helsinki, Finland, on May 23, 1958. He received the M.Sc. degree in electrical engineering from Helsinki University of Technology, Finland, in 1982, and the Ph.D. degree in electrical engineering from the Katholieke Universiteit Leuven, in Heverlee, Belgium, in 1987. From 1982 to 1984 he was employed as assistant at Helsinki University of Technology and as research assistant at the Technical Research Center of Finland. From 1984 to 1987 he was a research assistant at the E.S.A.T. Laboratory of the Katholieke Universiteit Leuven, enjoying also a temporary grant of the Academy of Finland. Since 1988 he has been with the Electronic Circuit Design Laboratory, Helsinki University of Technology, as senior assistant (1988–1990), and the director of the Integrated Circuit Design Unit of the Microelectronics Center (1990–1993). He was on leave of absence the academic year 1992–1993, acting as R&D manager in Fincitec Inc., Finland. From 1993 to 1996 he has been an associate professor, and since 1997 a full professor at the Faculty of Electrical Engineering and Telecommunications, Helsinki University of Technology. He became the Head of Electronic Circuit Design Laboratory year 1998. From 1997 to 1999 he was an associate editor of IEEE Transactions on Circuits and Systems I. He has been a guest editor for IEEE Journal of Solid-State Circuits and the Technical Program Committee Chairman for European Solid-State Circuits Conference year 2000. He has been awarded the Beatrice Winner Award in ISSCC'02 Conference year 2002. He specializes in CMOS and BiCMOS analog integrated circuits, particularly for telecommunication applications. He is author or co-author over a hundred and fifty international and national conference and journal publications on analog integrated circuits. He has several patents on analog integrated circuits.