Investigation of Microstructure Heterogeneity Using Multi-Length Scale Characterization of Additively Manufactured 316L SS Components for Nuclear Applications

Additive manufacturing allows for near net shape components to be manufactured with complex geometries and internal cooling channels while simultaneously allowing for microstructure control. Additive manufacturing has an added benefit of the possibility of removing the post processing needs associated with traditional nuclear component manufacturing. The microstructure of components built using laser powder bed fusion has been shown to be greatly affected by the build parameters. By altering the laser power, laser velocity, and the spot size the microstructure and, possibly, nanoscale partitioning may be tailored. In this study, nanoscale partitioning was confirmed to be the result of an abrupt transition of phase selection phenomenon from g - austenite (FCC) phase to d - ferrite (BCC) phase when moving from the outer edge of the melt pool to the interior, center region of the melt pool. This is inferred from a distinct shift in the Cr and Ni segregation in the inter – dendritic regions. This was achieved by studying four sample builds with varied build parameters, some of which underwent heat treatments. The samples were either built with Selective Laser Melting (SLM) or Concept Laser systems. Nanoscale segregation was identified in samples from the build varying parameters. All sample sets were confirmed ≥ 99% g-austenite (FCC) through X – ray diffraction. Solidification models, heat transfer models, and segmented etched optical microscopy images were performed and collected. This information, once gathered, led to the prediction of nanoscale partitioning patterns. The retained presence of nanoscale partitioning after massive transformation to ≥ 99% g-austenite (FCC) was confirmed through STEM/EDS analysis

Essays on the Economics of Student Achievement

Parents, lawmakers, and economists are all keenly interested in what affects student performance. This dissertation explores factors influencing student achievement in West Virginia with special attention devoted to public education resources and gender. Politicians and many parents of school age children believe increased levels of education funding or resources result in higher student achievement. Chapters 2 and 3 delve into this topic by exploring student achievement at different grade levels in West Virginia. The first public education funding or resource change to be analyzed occurred during a time period when the base for public education financing was expanding and funding levels were converging across school districts in the state. Data is a school-district level panel, including student achievement scores, from 1989 to 2002. The results suggest that rising expenditure levels may have had a positive effect on student achievement especially in areas with below average levels of spending prior to the policy change. The second

Divine benevolence to the poor : charity, religion and nationalism in early national New York City, 1784-1820

Includes bibliographical references (pages [183]-193).During the Early National Period, the United States witnessed the rise of reform organizations, or benevolent societies, dedicated to eliminating perceived social ills in the new republic. This project focuses on organizations in New York City that attempted to reduce the effects of poverty in the city by distributing material relief, promoting moral reform, and evangelizing the poor. I argue that a combination of Calvinist doctrine and nationalist sentiment motivated the founders of New York’s benevolent movement. Calvinist attitudes toward poverty, particularly the beliefs that the poor bore some responsibility for their situation and that vice produced poverty, shaped the societies’ relief policies. At the same time, nationalist concerns about the republic’s economic, political and social stability spurred the creation of benevolent societies. The founders hoped that their efforts at poor relief would play a role in creating a city, and perhaps a nation, more prosperous and morally superior to its European counterparts. Previous studies have examined the rise of organized benevolence, but this project is unique in its emphasis on religious doctrine and nationalism. Earlier works adhered to the “social control” model, which argued that the predominantly middleclass members of benevolent organizations hoped that their style of poor relief and moral reform would impose order upon the potentially volatile lower classes. This argument is true to a point, but it does not provide a complete explanation of the members’ motives. Eighteenth-century Protestant definitions of poverty combined with nineteenth-century secular notions of nationalism also brought about New York’s benevolent movement and created a new form of charity. This dissertation utilizes a combination of archival and published primary sources in addition to secondary literature. Archival sources such as minutes of the various societies’ meetings, letters, private papers and municipal records provide a great deal of information about the daily workings of the benevolent organizations. Published sources including the societies’ annual reports and sermons shed light on the founders’ motivations for organizing their societies as well as their attitudes toward the poor men, women and children they assisted.Ph.D. (Doctor of Philosophy

Investigation of biological matrices for novel biomarkers by modern mass spectrometric methods.

The primary objective was to introduce novel or develop existing techniques for the identification of new biomarkers within a range of biological matrices by modem mass spectrometric methods. Samples interrogated were hemodialysis concentrate, whole tissue sections and whole blood, with each having inherent challenges for use with mass spectrometry. Hence, published research has focused on other biological matrices or modes of detection for achieving the relevant aim. This current work overcame these issues by improving sample preparation including, the use of existing protocols for completely novel applications. Haemodialysate solution has proved most fruitful for identifying new candidate biomarkers. We have reproducibly detected 15 known and 6 novel uremic solutes within hemodialysate, a biological matrix previously deemed unsuitable for liquid chromatography/electrospray ionisation-mass spectrometry (LC/ESI-MS). This work included a validation of the novel methodology with stability and reproducibility investigations to test robustness. This highlighted a previously unrecorded thermally labile nature of some uremic solutes within the dialysate solution. A putative structural assignment has been made for 4 novel uremic solutes named, 5-(amino-1,2,-dihydroxy-ethyl)-3-nitrosooxy-[ 1,2,4]trioxine-3,6-diol, 2-(5,6-diamino-6-diazenyl-cyclohex-l-enyl)-2-hydroxy-acetimidic acid, N-[2-(7-hydroxy-3-methyl-ocatahydro-imidazo[ 1,5-alpha]pyridine-6-yl)-2-oxo-acetyl]-guanidine, and 3-(6-hydroxy-cyclohexa- 1,3-dienyl)-2-imino-3-oxopropionaldehyde. We have also identified that the chemical nature of solutes will dictate their removal during dialysis treatment and highly polar conventional biomarkers, urea and creatinine, are not representative of non-polar analyte excretion. This allows us to knowledgably suggest recommendations to improve future treatment modalities. The mass spectrometric analysis of whole tissue sections, in particular those that are paraffin embedded, pose a new range of challenges. Current MALDI matrices are unable to penetrate deep within tissue limiting their use to the tissue surface only. We have evaluated a range of novel dansylated MALDI matrices for this purpose that is detectable by fluorescence spectroscopy to aid in locating the matrix compound following application. Each dansylated MALDI matrix showed better penetration into the tissue sections, yet maintaining fluorescence detection, when compared to standard matrices CHCA, sinapinic acid and DHB. Of these novel matrices dansylhydrazine proved most successful in ionising proteins and peptides by forming a protonated molecule and related adducts. These additional mass shifted peaks, when included in a tryptic peptide database search, can improve the probability of the original protein/peptide identification. We now have the potential to obtain a total image of frozen tissue by using CHCA and dansylhydrazine in combination to ionise proteins/peptides at the surface or at depth, respectively. Further work is required for the preparation protocols with paraffin embedded sections for this total imaging principle to be applied. Finally we have illustrated the advantages of discovering novel haemoglobin variants in blood with a new ion mobility time-of-flight mass spectrometer, the Synapt HDMS system (Waters, MA, USA). We have identified a new variant that co-elutes with glycated haemoglobin peaks present in chromatograms used for conventional blood screening. Ion mobility technology and data extraction enhances the clarity of the results regarding multiple charging and variant characteristics. This enabled the exact determination of the amino acid substitution or mutation for the variant, with its assignment to a haemoglobin chain and the specific location within the chain