Carbon-inoculated complex

Calcium—Silicon. Calcium—silicon and calcium—barium—siUcon are made in the submerged-arc electric furnace by carbon reduction of lime, sihca rock, and barites. Commercial calcium—silicon contains 28—32% calcium, 60—65% siUcon, and 3% iron (max). Barium-bearing alloys contains 16—20% calcium, 9—12% barium, and 53—59% sihcon. Calcium can also be added as an ahoy containing 10—13% calcium, 14—18% barium, 19—21% aluminum, and 38—40% shicon These ahoys are used to deoxidize and degasify steel. They produce complex calcium shicate inclusions that are minimally harm fill to physical properties and prevent the formation of alumina-type inclusions, a principal source of fatigue failure in highly stressed ahoy steels. As a sulfide former, they promote random distribution of sulfides, thereby minimizing chain-type inclusions. In cast iron, they are used as an inoculant. 

The electrocatalysts for oxygen reduction were prepared as follows. These complex compounds were inoculated onto the carbon (AG-3, BET area near 800 m2/g) by means of adsorption from dimethylformamide solutions. The portion of complex compound weighed so as to achieve 3% of Co content was mixed with the carbon, then 5 ml of dimethylformamide per 1 g of the carbon were added and the mixture was cured at room temperature for 24 hours. Series of samples obtained were thermally treated (pyrolyzed), and the resulting grafted carbons were tested as electrode materials in the reaction of molecular oxygen reduction. 

Consistent with the preceding comments on the metabolism of xenobiotics in the presence of additional carbon substrates (Section 4.5.2), the situation with carbon additions may be quite complex and need not be addressed in detail again. Two simple examples may be given — in these, addition of glucose apparently elicited two differing responses although it should be emphasized that, since the concentration of such readily degradable substrates in natural aquatic systems will be extremely low, the environmental relevance of such observations will inevitably be restricted — (1) the rate of mineralization of phenol by the flora of natural lake water decreased (Rubin and Alexander 1983) and (2) the rate of mineralization of 4-nitrophenol was enhanced in lake water inoculated with a Corynebacterium sp. when rates of mineralization were low (Zaidi et al. 1988). 

Beyond the biological process of sullate reduction with subsequent metal precipitation as sulfides, other mechanisms of metal removal can be present during the runs, particularly in the inoculated column (A) precipitation as metals carbonates using the bicarbonate and/or carbonates formed during the reduction of sulfate by the SRB cells or by fermentation from other microorganisms, precipitation as metal hydroxides, complexing with substances excreted by the cells, and accumulation on the surface of cells, through reactions between metal ions and cell wall components [10]. 

In defined mixed culture the substrate is pasteurized or steriUzed and inoculated simultaneously with more than one pure culture. This can be beneficial for complex substrates and where the various strains use different carbon sources. For example, mixed cultures of Trichoderma reesei or Chaetomium cel-lulolyticum with Candida lipolytica resulted in increased protein production from wheat straw because the yeast uses glucose and prevents catabolite repression of the fungal cellulase [66,67]. 

A drawback of using complex degradation environments such as mature compost is that simultaneous characterisation of intermediate degradation products of determination of the carbon balance is difficult due to the presence of a great number of interfering compounds. To overcome this, an alternative test is currently under development based on an inoculated mineral bed based matrix . ... 

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