Phase transformations in periclase-spinel roofs of open-hearth furnaces with blowing through of the bath by compressed air

Conclusions The crystallochemical properties of the periclase and the spinels of the periclase-spinel bricks were radically changed during service in open-hearth furncces with blowing through of the bath with compressed air; new types of ferrite spinels and their solid solutions in periclase were formed. Periclase forms magnesiowüstite and magnesioferrite with ferric oxides resulting in a lowering of the melting point from 2800 to 1600°C. This type of transformation of periclase is one of the main causes of wear of periclase-spinel roofs by fusion.Under the service conditions chrome spinel is transformed into magnesioferrite and magnetite, with a lowering of the melting point from 2100 to 1750°C.In the working zone the lattice parameters of the solid solutions in periclase (magnesiowüstite) increased from 4.204 to 4.218 Å, indicating a considerable amount of divalent iron and manganese cations in the periclase crystal lattice.In the periclase-spinel bricks we identified independent types of spinel, represented by inverted (magnetite), almost inverted (magnesioferrite), partially inverted (chrompicotite) and ordinary (magnesiospinel) structures. In the spinels the cations are variously distributed at tetrahedral and octohedral lattice sites. In the working zone ferrite spinels (up to 90%) — magnesioferrite and magnetite — predominated; they have an inverted structure and low melting points. The content of easily fusible ferrite spinels increased with increasing intensity of blowing of air through the bath. The formation of a large amount of ferrite spinels is one of the main causes of the fusion and rapid wear of periclase-spinel roofs of open-hearth furnaces.Translated from Ogneupory, No. 2, pp. 25–31, February, 1969.     

Evidence for the Microwave Effect During the Annealing of Zinc Oxide

A microwave/conventional hybrid furnace has been used to anneal virtually fully dense zinc oxide ceramics under pure conventional and a microwave/conventional hybrid heating regime with a view to obtaining evidence for the "microwave effect" during the resulting grain growth. In each case it was ensured that each sample within a series had an identical thermal history in terms of its temperature/time profile. The results showed that grain growth was enhanced during hybrid heating compared with pure conventional heating; the greatest enhancement, a factor of ∼3 increase in average grain size, was observed in the range 1100°–1150°C. The grain growth exponent decreased from 3 during conventional heating to 1.4 during hybrid heating in this temperature range, suggesting an acceleration of the diffusional processes involved. Temperature gradients within the samples were found to be too small to explain the results. This suggests that clear evidence has been found to support the existence of a genuine "microwave effect."     

Pt/Sn bimetallic catalysts for the electro-oxidation of methanol: poisoning by silicate and phosphate unions

The influence of silicate and phosphate anions on the performance of Pt/Sn electrodeposited catalysts for the electro-oxidation of methanol has been studied. Both anions were found to have serious poisoning effects on the catalyst, whereas platinum catalysts were unaffected. The poisoning mechanism in both cases was thought to be initiated by the formation of either stannosilicates or stannophosphates species followed by the build-up of polymeric silicate or phosphate that ultimately blocks the active sites. The origin of the poisoning mechanism in both cases was found to be chemical rather than electrochemical. In the case of silicate, the poisoning species could be removed and the catalytic activity restored by chemical treatment with sulphuric acid.     

On the Fatty Acid Composition of Turkish Vegetable Oils

Because of the variety of climate conditions very different oil plants except of some tropical kinds grow in Turkey. In this work four groups of raw material of Turkish vegetable oils were investigated. The first group consists of olive, sunflower and cotton, which are important raw materials in Turkey. About 97% of the oil produced in Turkey base on these three raw materials. The second group consists of sesame, poppy, linseed, hemp-seed, rape, soyabean, safflower, castor bean and groundnut, which are temporary of lower importance for Turkey. The third group consists of the non-traditional oil raw materials like tobacco seed, grape seed, scabious, fig seed, tomato seed, laurel seed, pistacia terebinthus, rice bran, maize germs, anise seed, peach-stones and pumpkin seed. The fourth group consists of fruits rich in oil like hazel-nuts, walnuts, almonds and pistachio-nuts, whose production is of great importance in Turkey.     

Antennal olfactory responsiveness of three sympatricIps species [Ips avulsus (Eichhoff),Ips calligraphus (Germar),Ips grandicollis (Eichhoff)], to intra- and interspecific behavioral chemicals

Electroantennograms (EAGs) from male and femaleIps avulsus, I. calligraphus, andI. grandicollis to their pheromones and selected host odorants or kairomones verified the presence of antennal olfactory receptors in both sexes of each species capable of detecting ipsdienol, ipsenol,cis- andtrans-verbenol,endo-brevicomin -pinene, frontalin, and verbenone. Each species possesses receptors with lower thresholds and in greater abundance for the compounds they produce and to which they are behaviorally most responsive. Detection of bothIps andDendroctonus pheromones by the three cohabiting species provides a sensory basis for olfactory interactions among the species. Differences in both threshold and saturation levels for EAGs for the various behavioral chemicals could denote differences in specific behavioral roles for each compound.Texas Agricultural Experiment Station Paper Number TA-22463. This research was supported in part by McIntire-Stennis Project 1525, USDA-CR grants 85-CRCR-1-1856 and 86-CRCR-2019 and NATO Collaborative Research Grant 86-0710. The findings, opinions, and recommendations expressed herein are those of the authors and not necessarily those of the U.S. Department of Agriculture. All programs and information of the Texas Agricultural Experiment Station are available without regard to race, ethnic origin, religion, sex, or age.Mention of a trademark, proprietary product, or vendor does not constitute a guarantee or warranty of the product by the U.S. Department of Agriculture and does not imply its approval to the exclusion of other products or vendors that may also be suitable.     

Informational Entropy: a Failure Tolerance and Reliability Surrogate for Water Distribution Networks

Evolutionary algorithms are used widely in optimization studies on water distribution networks. The optimization algorithms use simulation models that analyse the networks under various operating conditions. The solution process typically involves cost minimization along with reliability constraints that ensure reasonably satisfactory performance under abnormal operating conditions also. Flow entropy has been employed previously as a surrogate reliability measure. While a body of work exists for a single operating condition under steady state conditions, the effectiveness of flow entropy for systems with multiple operating conditions has received very little attention. This paper describes a multi-objective genetic algorithm that maximizes the flow entropy under multiple operating conditions for any given network. The new methodology proposed is consistent with the maximum entropy formalism that requires active consideration of all the relevant information. Furthermore, an alternative but equivalent flow entropy model that emphasizes the relative uniformity of the nodal demands is described. The flow entropy of water distribution networks under multiple operating conditions is discussed with reference to the joint entropy of multiple probability spaces, which provides the theoretical foundation for the optimization methodology proposed. Besides the rationale, results are included that show that the most robust or failure-tolerant solutions are achieved by maximizing the sum of the entropies.     

Corundum hydraulically hardening rammed compounds with a reduced grain size

Conclusions The production and use of rammed hydraulically hardening corundum compounds with different maximum grain sizes (from 1 to 7 mm) permits intermediate repairs of the linings of ladles of a steel ladle treatment unit, increasing their life.It is possible to determine the quantity of binder for obtaining the maximum strength by calculation by use of the coefficient of optimization, which is the portion of binder required per unit of specific surface of the mixture of filler grains. For the corundum hydraulically hardening compounds the optimum value of this coefficient is 0.8–1.2.Translated from Ogneupory, No. 2, pp. 40–43, February, 1987.