Thesis--Wisconsin. / Vita. Includes bibliographical references (leaf 119).

The problem of this study was to develop a curriculum based on present destructive testing procedures used in industry dealing with the mechanical properties of ferrous and non-ferrous metals, and to organize the curriculum at the university level.

No description available.

In the present study, the corrosion behaviour of several magnesia-chrome (MC) and magnesia-alumina spinel (MA) bricks against fayalite type slags was investigated and the role of the spinel phases was highlighted. The experimental results revealed that the corrosion resistance of the MC bricks was superior to the MA bricks against KIVCET slags in static and dynamic conditions. As a result of the interaction between MgO from MC bricks and the slag, a modified forsterite phase (Mg, Fe, Zn, Ca) ���SiO��� was formed, which destroyed the precipitated complex spinel bonds at the grain boundaries of periclase and magnesia-chromia spinel. Furthermore, both MgO and MgO-MgAl���O��� spinel in the MA brick dissolved into the slag, which resulted in modified forsterite phases of (Mg, Fe, Zn, Ca)���SiO��� and (Mg, Fe, Zn)(Fe, Al)���0��� complex spinels, respectively. In addition, the accretion formation in the KIVCET furnace was investigated through solubility experiments of Cr���0��� in the KIVCET slag with various amounts of lead, which revealed that the net contribution of Cr���03 to the spinel formation is the highest in the barren (no Pb) slag, followed by high-lead (11% Pb) and it is the lowest for the low-lead (6% Pb) slag. The amount of spinel solid solution increased consistently with increasing Cr���0��� dissolved and the PbO existent in the slag. From examinations of several used bricks from the tuyere area of a Peirce Smith nickel converter, it was found that the corrosion is due to the interaction of the partially oxidized matte penetrating deep into the brick and the magnesia grains forming (Mg, Fe, Ni, Co) XOy spinels. Analyses of brick samples used in the KIVCET Electric Furnace roof identified deep reaching sulphation, which weakened the bonding phase between coarse magnesia grains. In the Bottom Blown Oxygen Converter, a highly aggressive lead and bismuth oxide rich slag penetrated deep into the brick, which destroyed the grain boundaries, causing the refractory to be easily eroded at the refractory-slag interface. Our studies concluded that the spinel phases, either as magnesium chromate, magnesium aluminate or complex spinel [(Mg, Fe)(Cr, Al, Fe) ���O���], enhanced the corrosion resistance of a basic refractory to fayalite type slags from the non-ferrous smelting and converting furnaces.

Vibrio cholerae, the causative agent of the diarrheal disease cholera, must acquire iron to survive. Although iron is relatively abundant, it forms insoluble ferric complexes in the presence of oxygen. The more soluble ferrous iron is limited to anaerobic or reducing environments. To meet the nutritional needs of the cell, V. cholerae encodes many different ferric iron transport systems but only one characterized ferrous iron transporter, Feo. Feo is widely distributed in bacteria and archaea, but the mechanism for transport is not known. In this study, basic characterization of the V. cholerae feoABC operon was performed to gain further understanding about a critical iron transport system. Each gene in the operon, feoA, feoB, and feoC, was found to be required for ferrous iron uptake. FeoB, an inner membrane protein, is considered to be the ferrous permease but functions for FeoA and FeoC are not known. These studies show that neither FeoA nor FeoC is required for expression of feoB, suggesting that these proteins are required for Feo function. Analysis of the composition of the Feo transporter using a bacterial adenylate cyclase two-hybrid system indicated interactions between Feo proteins, specifically, between FeoC and the cytoplasmic portion of FeoB. This result indicates that feoC encodes a protein that interacts with FeoB and is necessary for ferrous iron transport. / text

The oxidation of ferrous in acidic sulfate media by dissolved oxygen is an important reaction in any sulfide mineral leach process that uses ferric as a surrogate oxidant. Ferric is reduced as it oxidizes metal sulfides, and the resulting ferrous is re-oxidized by dissolved oxygen. The oxidation of ferrous to ferric by dissolved oxygen is quite slow outside of elevated pressure-temperature autoclaves. However, pyrite in solution has been found to have a catalytic effect on the reaction, speeding it up significantly. This effect is particularly significant in the context of the Galvanox™ acidic sulphate atmospheric leach process. To quantify the kinetics of this reaction and the effect of pyrite, tests were run in an atmospheric batch reactor with constant tracking of pH and redox potential. The kinetics of this reaction were quantified with respect to primary variables such as acidity, pyrite pulp density, temperature, and total iron concentration. Secondary factors such as copper concentration, gas liquid mixing rate and the source of pyrite mineral were also considered. Redox potential is a logarithmic function of the ratio of the activity of free ferric to free ferrous and is complicated by speciation within the Fe(III)-Fe(II)-H₂SO₄-H₂O system. Correlating redox potential data with extent of reaction was achieved by using permanganate redox titration and the isokinetic technique to link redox potential data directly to the fraction of ferrous reacted. This technique is effective over the potential range of interest – 360 to 510 mV vs Ag/AgCl. Under these conditions the leaching rate of pyrite is appreciable, so the rate of pyrite dissolution was predicted with the shrinking sphere model developed by Bouffard et al. Ferrous oxidation in solution was simulated with an adjusted version of the model of Dreisinger and Peters, which also accounts for the catalytic effect of dissolved copper. Oxygen solubility was predicted using the model of Tromans. Experimental data show a clear enhancing effect of pyrite on ferrous oxidation. A mathematical model of this effect applicable to the conditions of Galvanox™ leaching is presented.

Lubrication is the lifeblood of mechanical device during the operating conditions, so that the lubricating oil detection becomes one of an important modern technology. The operator can be as early as possible to know whether the abnormal wear occurs by detecting concentration of ferrous debris in the lubricating oil. Detecting the viscosity of lubricating oil can also allow the operator to monitor the deterioration degree of lubricating oil due to environmental factors, in order to ensure whether the lubricating oil losing its effectiveness. Our laboratory previously developed a prototype of integrated apparatus for detecting the concentration of ferrous debris and the viscosity of lubricant in a single process. This study focuses on improving this prototype, so that the apparatus possesses a LCD displayer and commercialization. The design of the integrated apparatus contains a sampling unit, a measurement unit of the ferrous debris concentration, a measurement unit of the viscosity, a data acquisition system, and LCD displayer panel. In measurement unit of the ferrous debris concentration, Hall IC is used as a sensor to measure the concentration of ferrous debris by detecting the change of magnetic flux density between the magnetic poles due to the stacking of ferrous debris. In the measurement unit of the viscosity of the lubricating oils, the piston is used to squeeze the oil into the tank to measure the viscosity by detecting the load. These two units are integrated into a measuring device, and there is no interference between the values measured by the Hall IC and the load cell. Finally, these two signals are fed to a personal computer for data analysis to obtain the concentration of ferrous debris and the viscosity of lubricant. Consequently, the operator can directly observe the measured results.

Thesis (Ph. D.)--University of Pittsburgh, 1915. / Vita.

The oxidation of ferrous in acidic sulfate media by dissolved oxygen is an important reaction in any sulfide mineral leach process that uses ferric as a surrogate oxidant. Ferric is reduced as it oxidizes metal sulfides, and the resulting ferrous is re-oxidized by dissolved oxygen. The oxidation of ferrous to ferric by dissolved oxygen is quite slow outside of elevated pressure-temperature autoclaves. However, pyrite in solution has been found to have a catalytic effect on the reaction, speeding it up significantly. This effect is particularly significant in the context of the Galvanox™ acidic sulphate atmospheric leach process. To quantify the kinetics of this reaction and the effect of pyrite, tests were run in an atmospheric batch reactor with constant tracking of pH and redox potential. The kinetics of this reaction were quantified with respect to primary variables such as acidity, pyrite pulp density, temperature, and total iron concentration. Secondary factors such as copper concentration, gas liquid mixing rate and the source of pyrite mineral were also considered. Redox potential is a logarithmic function of the ratio of the activity of free ferric to free ferrous and is complicated by speciation within the Fe(III)-Fe(II)-H₂SO₄-H₂O system. Correlating redox potential data with extent of reaction was achieved by using permanganate redox titration and the isokinetic technique to link redox potential data directly to the fraction of ferrous reacted. This technique is effective over the potential range of interest – 360 to 510 mV vs Ag/AgCl. Under these conditions the leaching rate of pyrite is appreciable, so the rate of pyrite dissolution was predicted with the shrinking sphere model developed by Bouffard et al. Ferrous oxidation in solution was simulated with an adjusted version of the model of Dreisinger and Peters, which also accounts for the catalytic effect of dissolved copper. Oxygen solubility was predicted using the model of Tromans. Experimental data show a clear enhancing effect of pyrite on ferrous oxidation. A mathematical model of this effect applicable to the conditions of Galvanox™ leaching is presented.

No description available.