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Dynamic Property Evaluation Of Frother, Yunkai Xia
Dynamic Property Evaluation Of Frother, Yunkai Xia
Graduate Theses, Dissertations, and Problem Reports
Fourteen solvents were evaluated through frothing test and laboratory flotation batch tests. A new frothing parameter, initial dynamic froth index (IDFI), is proposed to compare the frothability of solvent. IDFI is derived from initial retention time of froth instead of retention time. IDFI is defined as the limiting slope of the initial retention time versus concentration curves while the concentration approaches zero. IDFI value depends on chemical structure and molecular weight of the solvent. Combined with normalized frothability index (NFI), normalized collapse rate constant (NKc), hydrophilic-lipophilic balance (HLB) and dynamic froth index (DFI), IDFI can be a useful index in …
Evaluation Of Lubricants For Cold Forming Of Steels By Double-Cup Extrusion Tests, Shivakumaran Bharadwaj Venkataraman
Evaluation Of Lubricants For Cold Forming Of Steels By Double-Cup Extrusion Tests, Shivakumaran Bharadwaj Venkataraman
Graduate Theses, Dissertations, and Problem Reports
The double-cup extrusion testing method was chosen for measuring the pressure and material flow parameters in order to quantify the frictional shear factor between the workpiece and the forming tool in cold metal forming processes. The test was adapted to be used under production conditions and applied to characterize and compare the lubrication properties of different types of lubricants and coatings.;It was found to be a useful approach to estimate the relative efficiency of different lubricants and coating methods. It indicated that one specific lubricant has significantly superior lubricant characteristics than others.;FEA analysis of the experimental setup was constructed to …
Composition Effects On Macroscopic Solidification Segregation Of Superalloys, Wei Chen
Composition Effects On Macroscopic Solidification Segregation Of Superalloys, Wei Chen
Graduate Theses, Dissertations, and Problem Reports
This research work investigates primarily the composition effects on solidification macrosegregation, i.e. freckles, in superalloys. First, the freckling mechanism of superalloys is developed using the physical simulation of freckle formation in specially designed model alloys. It is found that freckles originate from dendrite irregularities at the solidification front. The freckle channels flow downward in Nb-containing alloys and upward in T-containing alloy under horizontal solidification conditions. The horizontal solidification correctly simulates the horizontal component in remelt ingot where freckling potential is the highest. Based on the result, key control parameters for freckling are identified.;Thermodynamic simulation approach is employed to study the …
Corrosion Between Orthodontic Archwires And Bracket Couples, Brian Costello O'Leary
Corrosion Between Orthodontic Archwires And Bracket Couples, Brian Costello O'Leary
Graduate Theses, Dissertations, and Problem Reports
Nickel-containing orthodontic wires have been reported to cause allergic reactions in sensitive individuals. An allergic reaction is related to corrosion of the alloys and subsequent leaching of nickel ions into the oral cavity. The purpose of this study was to determine if there is a significant difference in the corrosive potential of stainless steel, NiTi and TMA wires either alone or when coupled with a stainless steel bracket.;Using potentiostatic anodic polarization, the samples were tested in 0.9% NaCl solution at room temperature with neutral pH. The breakdown potentials of stainless steel, NiTi, TMA, and the stainless steel bracket were 600 …