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The state of the interface between slag and carbon determines the slag foaming behavior and thus the effectiveness of carbon in electric arc furnace (EAF) steelmaking. This paper explores the interaction between synthetic slag and carbonaceous materials derived from various sources, including bio-char produced by two different technologies, graphite, coke, and char from tire pyrolysis. Different interfacial phenomena were found between slag and the carbonaceous materials examined. The interactions between bio-char and slag are found to be poor in comparison with other carbonaceous materials. Carbonaceous materials were characterized in terms of their chemical composition and the results obtained suggested that interfacial phenomena were not dominated by ash in the carbonaceous material. The effects of carbon crystalline structure on interaction with slag were evaluated by Raman spectroscopy and X-ray diffraction. Surface properties of the samples were evaluated using scanning electron microscopy, and surface morphology was identified as the principal factor affecting the interaction of slag on carbonaceous particles. The smooth surface of bio-char results in reduced slag foaming. This finding forms the basis for future research on the production of bio-char to be used as a slag foaming agent in EAF steelmaking.

The decomposition of ethylene by pulsed, unfocussed CO2-laser radiation has been studied at pressures from 500 to 3000 Torr, using the P(14) line of the 10.6μm band (v=949.48cm−1) at incident fluences from about 0.1 to 1.0J/cm2. Major products in order of decreasing importance were 1,3-butadiene, acetylene, ethane, propane, 1-butene and methane. These are known products of the thermal free-radical chain decomposition, and it is concluded that the laser-induced decomposition under our conditions is a transient bulk thermal reaction occurring in a thin disc of heated gas close to the entrance window of the reaction vessel at temperatures ranging from about 1000 to 1500K. As in the thermal decomposition, cyclobutane was observed to be a minor product, which in a sequence of laser pulses approached a final constant concentration. The possibility that this corresponded to an equilibrium concentration at some “effective” reaction temperature was explored. Computer simulation was used to model the accumulation of cyclobutane in the system, both in a single pulse and in a sequence of pulses, and predictions of this model were compared with experiment. It was concluded that cyclobutane could be used in this way as an approximate internal thermometer, within certain limits. Mechanisms of formation of the free-radical chain products are discussed. It is concluded that the chains are initiated by the bimolecular disproportionation reaction, 2C2H4 → C2H3+C2H5, and that secondary initiation by dissociation of the product, 1-butene, becomes increasingly important as the reaction proceeds, leading to autocatalysis. It is further concluded that the radical chain decomposition in this system is a transient process occurring in a brief time interval following the short laser pulse (FWHM=110ns), and is far from steady-state conditions.

Collagenase from Clostridium histolyticum induced haemorrhages when applied to the surface of dog lung; it exerted a similar effect on mouse lung when injected intrathoracically. Injected into rat paws, bacterial collagenase induced haemorrhage and oedema. Effects of collagenase were prevented by several procedures that inhibit collagenolytic activity (heating at various temperatures and incubation with metal-complexing agents such as EDTA, penicillamine and dithiothreitol). Protein protease inhibitors, dexamethasone and standard acidic anti-inflammatory drugs had only a slight or no effect on collagenase-induced haemorrhages; dexamethasone and acidic anti-inflammatory drugs blocked collagenase-induced oedema. Inhibition of endogenous kinin-releasing mechanisms by administration of hexadimethrine, a recognized inhibitor of the activation of clotting Factor XII, and depletion of kininogen by administration of carrageenin blocked collagenase-induced oedema. Collagenase did not increase permeability of rat skin vessels, nor did it release potential inflammatory mediators, such as bradykinin or prostaglandins, from plasma or platelets. Bacterial collagenase-induced haemorrhage presumably resulted from enzymatic destruction of membranous structures; at least a portion of the inflammatory response may be due to activation of a kinin-like system.

The absorption of pulsed CO2-laser radiation by ethylene has been measured at total pressures from 25 to 3000 Torr, using the P(12) and P(14) lines in the 10.6 μm band, with incident fluences from 0.1 to 0.7 J/cm2. Marked deviations from the Beer-Lambert absorption law were observed, with the effective absorption coefficient varying with pressure, fluence, absorption path-length and the addition of non-absorbing gas. Pressure broadening of the rotational lines of the ethylene absorption spectrum was shown to be the major cause of these deviations, together with lesser effects which can be attributed to the rise in temperature of the absorbing gas during the laser pulse.

Clostripain (clostridiopeptidase B, E.C. 3.4.4.20) is a thiol proteinase found in extracts from cultures of Clostridium histolyticum (Ogle and Tytell, 1953; Labouesse and Gros, 1960), and displays a marked specificity for the carboxyl linkage of arginine (Gros and Labouesse, 1960; Mitchell and Harrington, 1968). Clostripain has been reported to release kinin-like polypeptides directly from bovine or horse kininogen-containing preparations (Prado, et al., 1956; Prado and Prado, 1962). In the course of investigations concerning the haemorrhagic and pro-inflammatory activity of bacterial collagenase (Giroux, Lefort and Vargaftig, 1976) we found that clostripain, a contaminant of one collagenase preparation, displayed indirect kinin-releasing activities which had not been described before. This communication reports our investigation of the mechanism of such release.