Corrosion Protection of Low Carbon Steel By Cation Substituted Magnetite (Fe3o4)

Corrosion Protection of Low Carbon Steel By Cation Substituted Magnetite (Fe3o4)

Date: May 2013
Creator: Phadnis, Ameya
Description: Surfaces of low carbon steel sheet were modified by exposure to highly caustic aqueous solutions containing either chromium or aluminum cations. Corrosion resistances of such surfaces were compared with that of steel surfaces exposed to plain caustic aqueous solution. In all cases a highly uniform, black coating having a spinel structure similar to magnetite (Fe3O4) was obtained. The coated steel surfaces were characterized using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and Fourier transform infrared spectrophotometry (FTIR). Polarization resistances (Rp) of modified steel surfaces were measured and compared with that of bare steel surfaces. Results indicate that chromium (Fe2+ Fe3+x Cr3+1-x) or aluminum (Fe2+ Fe3+x Al3+1-x) substituted spinel phases formed on steel surfaces showed higher Rp values compared to only magnetite (Fe2+ 2Fe3+O4) phase formed in the absence of either chromium or aluminum cations. Average Rp values for steel surfaces with chromium containing spinel phase were much higher (21.8 k?) as compared to 1.7 k? for bare steel surfaces. Steel surfaces with aluminum containing spinel phase and steels with plain magnetite coated samples showed average Rp values of 3.3 k? and 2.5 k? respectively. XPS and EDS analysis confirmed presence of cations of chromium and ...
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Factors influencing horizontal cracking in continuously reinforced concrete pavements (CRCP).

Factors influencing horizontal cracking in continuously reinforced concrete pavements (CRCP).

Date: August 2008
Creator: Sudoi, Elias K.
Description: This research presents the results on an experimental investigation to identify the significant factors influencing horizontal cracking in continuously reinforced concrete pavements (CRCP). An in-depth analysis of the microstructure, morphological characteristics of the interfacial transition zone (ITZ) and the observation of cracking using the environmental scanning electron microscope (ESEM) was done. Characterization of oxides using Fourier transform infrared spectroscopy (FTIR) and electron dispersive x-ray spectroscopy (EDS) was also performed. Water to cement ratio (w/c) and rebar temperature had a significant influence on the rebar-concrete bond strength. The 28-day shear strength measurements showed an increase in rebar-concrete bond strength as the water to cement ratio (w/c) was reduced from 0.50 to 0.40. There was a reduction in the peak pullout load as the temperature increased from 14oF to 252oF for the corroded and non-corroded rebar experiments. The corroded rebar pullout test results showed a 20-50 % reduction in bond strength compared to the non-corroded rebars. FTIR measurements indicated a presence of lepidocrocrite (γ -FeOOH) and maghemite (γ -Fe2O3) on the ITZ. ESEM images showed the existence of microcracks as early as three days after casting with the bridging of these cracks between coarse aggregate locations in the interfacial zone propagating through ...
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Effects of Minimum Quantity Lubrication (Mql) on Tool Life in Drilling Aisi 1018 Steel

Effects of Minimum Quantity Lubrication (Mql) on Tool Life in Drilling Aisi 1018 Steel

Date: August 2012
Creator: Maru, Tejas
Description: It has been reported that minimum quantity lubrication (MQL) provides better tool life compared to flood cooling under some drilling conditions. In this study, I evaluate the performance of uncoated HSS twist drill when machining AISI 1018 steel using a newly developed lubricant designed for MQL (EQO-Kut 718 by QualiChem Inc.). A randomized factorial design was used in the experiment. The results show that a tool life of 1110 holes with a corresponding flank wear of 0.058 mm was realized.
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Mist Characterization in Drilling 1018 Steel

Mist Characterization in Drilling 1018 Steel

Date: August 2012
Creator: Cole, Ian
Description: Minimum quantity lubrication replaces the traditional method of flood cooling with small amounts of high-efficient lubrication. Limited studies have been performed to determine the characteristics of mist produced during MQL. This study investigated the mist concentration levels produced while drilling 1018 steel using a vegetable based lubricant. ANOVA was performed to determine whether speed and feed rates or their interactions have a significant effect on mist concentration levels and particle diameter. It was observed that the concentration levels obtained under all four speed and feed rate combinations studied exceeded the current OSHA and NIOSH standards.
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Errors in skin temperature measurements.

Errors in skin temperature measurements.

Date: December 2008
Creator: Dugay, Murielle
Description: Numerical simulation is used to investigate the accuracy of a direct-contact device for measuring skin-surface temperature. A variation of thermal conductivity of the foam has greater effect on the error rather than a variation of the blood perfusion rate. For a thermal conductivity of zero, an error of 1.5 oC in temperature was identified. For foam pad conductivities of 0.03 and 0.06 W/m-oC, the errors are 0.5 and 0.15 oC. For the transient study, with k=0 W/m-oC, it takes 4,900 seconds for the temperature to reach steady state compared with k=0.03 W/m-oC and k=0.06 W/m-oC where it takes 3,000 seconds. The configuration without the foam and in presence of an air gap between the skin surface and the sensor gives the most uniform temperature profile.
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Comparing Latent Dirichlet Allocation and Latent Semantic Analysis as Classifiers

Comparing Latent Dirichlet Allocation and Latent Semantic Analysis as Classifiers

Date: December 2011
Creator: Anaya, Leticia H.
Description: In the Information Age, a proliferation of unstructured text electronic documents exists. Processing these documents by humans is a daunting task as humans have limited cognitive abilities for processing large volumes of documents that can often be extremely lengthy. To address this problem, text data computer algorithms are being developed. Latent Semantic Analysis (LSA) and Latent Dirichlet Allocation (LDA) are two text data computer algorithms that have received much attention individually in the text data literature for topic extraction studies but not for document classification nor for comparison studies. Since classification is considered an important human function and has been studied in the areas of cognitive science and information science, in this dissertation a research study was performed to compare LDA, LSA and humans as document classifiers. The research questions posed in this study are: R1: How accurate is LDA and LSA in classifying documents in a corpus of textual data over a known set of topics? R2: How accurate are humans in performing the same classification task? R3: How does LDA classification performance compare to LSA classification performance? To address these questions, a classification study involving human subjects was designed where humans were asked to generate and classify documents ...
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Effects of minimum quantity lubrication in drilling 1018 steel.

Effects of minimum quantity lubrication in drilling 1018 steel.

Date: December 2008
Creator: Shaikh, Vasim
Description: A common goal for industrial manufacturers is to create a safer working environment and reduce production costs. One common method to achieve this goal is to drastically reduce cutting fluid use in machining. Recent advances in machining technologies have made it possible to perform machining with minimum-quantity lubrication (MQL). Drilling takes a key position in the realization of MQL machining. In this study the effects of using MQL in drilling AISI 1018 steel with HSS tools using a vegetable based lubricant were investigated. A full factorial experiment was conducted and regression models were generated for both surface finish and hole size. Lower surface roughness and higher tool life were observed in the lowest speed and feed rate combination.
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Mist and Microstructure Characterization in End Milling Aisi 1018 Steel Using Microlubrication

Mist and Microstructure Characterization in End Milling Aisi 1018 Steel Using Microlubrication

Date: August 2013
Creator: Shaikh, Vasim
Description: Flood cooling is primarily used to cool and lubricate the cutting tool and workpiece interface during a machining process. But the adverse health effects caused by the use of flood coolants are drawing manufacturers' attention to develop methods for controlling occupational exposure to cutting fluids. Microlubrication serves as an alternative to flood cooling by reducing the volume of cutting fluid used in the machining process. Microlubrication minimizes the exposure of metal working fluids to the machining operators leading to an economical, safer and healthy workplace environment. In this dissertation, a vegetable based lubricant is used to conduct mist, microstructure and wear analyses during end milling AISI 1018 steel using microlubrication. A two-flute solid carbide cutting tool was used with varying cutting speed and feed rate levels with a constant depth of cut. A full factorial experiment with Multivariate Analysis of Variance (MANOVA) was conducted and regression models were generated along with parameter optimization for the flank wear, aerosol mass concentration and the aerosol particle size. MANOVA indicated that the speed and feed variables main effects are significant, but the interaction of (speed*feed) was not significant at 95% confidence level. The model was able to predict 69.44%, 68.06% and 42.90% of ...
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