Compositional tuning, crystal growth, and magnetic properties of iron phosphate oxide

2017 Spring.Includes bibliographical references.Iron phosphate oxide, Fe3PO4O3, is a crystalline solid featuring magnetic Fe3+ ions on a complex lattice composed of closely-spaced triangles. Previous work from our research group on this compound has proposed a helical magnetic structure below T = 163 K attributed to J1-J2 competing interactions between nearest-neighbor and next-nearest-neighbor iron atoms. This was based on neutron powder diffraction featuring unique broad, flat-topped magnetic reflections due to needle-like magnetic domains. In order to confirm the magnetic structure and origins of frustration, this thesis will expand upon the research focused on this compound. The first chapter focuses on single crystal growth of Fe3PO4O3. While neutron powder diffraction provides insight to the magnetic structure, powder and domain averaging obfuscate a conclusive structure for Fe3PO4O3 and single crystal neutron scattering is necessary. Due to the incongruency of melting, single crystal growth has proven challenging. A number of techniques including flux growth, slow cooling, and optical floating zone growth were attempted and success has been achieved via heterogenous chemical vapor transport from FePO4 using ZrCl4 as a transport agent. These crystals are of sufficient size for single crystal measurements on modern neutron diffractometers. Dilution of the magnetic sublattice in frustrated magnets can also provide insight into the nature of competing spin interactions. Dilution of the Fe3+ lattice in Fe3PO4O3 is accomplished by substituting non-magnetic Ga3+ to form the solid solution series Fe3-xGaxPO4O3 with x = 0, 0.012, 0.06, 0.25, 0.5, 1.0, 1.5. The magnetic susceptibility and neutron powder diffraction data of these compounds are presented. A dramatic decrease of the both the helical pitch length and the domain size is observed with increasing x; for x > 0.5, the compounds lack long range magnetic order. The phases that do exhibit magnetic order show a decrease in helical pitch with increasing x as determined from the magnitude of the magnetic propagation vector. This trend can be qualitatively reproduced by increasing the ratio of J2/J1 in the Heisenberg model. Intriguingly, the domain size extracted from peak broadening of the magnetic reflections is nearly equal to the pitch length for each value of x, which suggests that the two qualities are linked in this unusual antiferromagnet. The last chapter focuses on the oxyfluoride Fe3PO_7-xFx. Through fluorination using low-temperature chimie douce reactions with polytetrafluoroethylene, the magnetic properties show changes in the magnetic susceptibility, isothermal magnetization, and neutron powder diffraction. The magnetic susceptibility shows a peak near T = 13 K and a zero field cooled/field cooled splitting at T = 78 K. The broad, flat-topped magnetic reflections in the powder neutron diffraction exhibit a decrease in width and increase in intensity. The changes in the neutron powder diffraction suggest an increase in correlation length in the ab plane of the fluorinated compound. Iron phosphate oxide is a unique lattice showing a rich magnetic phase diagram in both the gallium-substituted and fluorinated species. While mean-field interactions are sufficient to describe interactions in the solid solution series Fe{3-xGaxPO4O3, the additional magnetic transitions in Fe3PO7-xFx suggest a more complicated set of interactions

Kentucky’s K-12 Public School Spending and Its Relationship to Enrollment Percentages of Students with Limited English Proficiency and Students Eligible for the Free and Reduced-Price Lunch Program

Public school funding formulas vary broadly between states in both the levels of funding and the mechanisms through which funding is distributed. Most states provide targeted funding for student populations that need supplemental resources, including low-income and limited English proficiency student populations, as does the Federal Elementary and Secondary Education Act (ESEA). In the past, a lack of school level enrollment and financial data made it difficult to determine whether funding provided to local education agencies has been equitably distributed to the schools with whom they are affiliated. The 2015 Federal Every Student Succeeds Act requires that school-level enrollment and financial information be publicly available, providing an opportunity to assess the relationship between student enrollment and local, state, and Federal spending

An Art Teacher\u27s Personal and Prictical Knowledge of the Classroom: An Ethnographic Study

The purpose of this project was to search for meaning in the socially constructed and constantly changing environment and practical knowledge of a Fine Arts Instructor. The researcher wanted the teacher to gain new insights on the subject of self, instruction, subject matter, role as teacher, role as colleague, curriculum development and the lives of students. A yearlong internship was conducted in which the researcher took on the role of observer and then of participant-observer. Ajournal of field notes was chronicled throughout the internship. From this journal, interview questions were developed and two interviews were conducted. The goal was to learn from another\u27s life experiences within the world of teaching through ethnographic methods. It was found that lessons most critical to life are often those gained only through one\u27s experiences and that in order to be a successful teacher, one must consider the well-being of students above all other factors in teaching and learning

Land Use and Zoning Law

Since the early days of nuisance law, but especially since the early twentieth century and the validation of zoning ordinances, land use planning and management have been fundamental roles of local government. As evinced by its state code, the Commonwealth of Virginia recognizes the essential role that localities play in land use planning. The Virginia Code requires that localities create planning commissions, adopt comprehensive plans, and, if the localities have adopted zoning ordinances, establish boards of zoning appeals. As most of the implementation of these mandates is left to individual localities, the form of implementation is not uniform but naturally varies from county to county and city to city

The Grapes of Wrath: Encouraging Fruitful Collaborations Between Local Governments and Farm Wineries in the Commonwealth

While there is fairly substantial federal regulation in the field of wine law, this essay\u27s scope will be limited to the interplay of Virginia\u27s state and local laws that affect wineries close to home. Within that scope, this essay\u27s purpose is threefold. First, it will highlight the key legislation and ordinances that affect farm wineries. Second, it will discuss the interplay between state and local level regulations, concluding that the General Assembly has intended to retain near exclusive regulatory powers over farm wineries. Third, it will briefly analyze the impact of the wine industry on three Virginia counties, concluding that a more temperate approach to local regulation of the wine industry in the Commonwealth is desirable for optimal growth and participation in one of Virginia\u27s most vibrant economic sectors

Review of Life Cycle Sustainability Assessment and Potential for Its Adoption at an Automotive Company

The aim of this paper is to guide the next steps of a PhD thesis through a structured review of the state of the art and implementation of Life Cycle Sustainability Assessment (LCSA), and to identify challenges and potentials for its adoption at an automotive company. First, the structured literature review was conducted on LCSA to screen the current methodological and practical implementations and to identify the main research needs in the field. Second, a research on the current status of LCSA within the automotive industry was carried out by means of investigation of published sources of 15 Original Equipment Manufacturers (OEM). By combining the results of both steps and consulting with decision makers, the challenges and potential for adopting LCSA at an automotive company were identified. The main challenges for adoption of LCSA were found to be: (1) the consistent execution of the three life cycle based assessment methods; (2) the comparatively low maturity of Social Life Cycle Assessment (S-LCA); and (3) the adequate presentation and interpretation of results. Next steps towards implementation would be a case study to gather experience on the combined execution of the three life cycle based assessments at an automotive company. Furthermore, it should be determined what the needs of decision makers at an automotive company are regarding the aggregation and interpretation of environmental, social, and economic impacts

To Destroy or to Preserve: Urban Renewal and the Legal Foundation of Historic District Zoning

Historic preservation and urban renewal are often thought to be polar opposites. Where one seeks to preserve, the other generally seeks to destroy in order to rebuild. While the programs appear on the surface to be in opposition, this Thesis seeks to demonstrate that there is a fundamental connection between the underlying legal principles of historic zoning and urban renewal. To that end, the jurisprudence involving historic zoning and aesthetic regulations before and after the seminal urban renewal case of Berman v. Parker has been collected and analyzed. This analysis revealed that courts were hesitant to support aesthetic, and by extension would have been unlikely to support historic zoning, prior to the Supreme Court’s validation of urban renewal programs in Berman. For example, in 1949 the Supreme Court of Massachusetts stated that specifically stated that a zoning regulation cannot be enacted solely to preserve the beauty of a community. In Berman, however, the United States Supreme Court justified urban renewal on the basis that governments should be able to condemn and regulate property for the creation of a more attractive community. An analysis of the jurisprudence following Berman indicated that courts were more likely to uphold aesthetic or historic zoning ordinances. For example, in a 1955 opinion, the Supreme Court of Massachusetts cited Berman and stated that, because construction of aesthetically or historically incompatible structures could destroy the historic character of a town, historic zoning ordinances fell within the scope of the police power. In short, the cases identified by this Thesis ultimately indicated that Berman had an impact on the acceptance of aesthetic and historic zoning. Therefore, they suggest that the programs of historic zoning and urban renewal, while seemingly in opposition, share fundamental legal roots

2010-2011 Veterans Law Update

Part I will cover updates related directly to veterans\u27 benefits and rights. Part II will focus on updates to rules involving veterans\u27 caregivers and healthcare facilities. Part III will cover proposed rules dealing with veterans\u27 claims and insurance. Part IV will focus on rules and case law covering the VA\u27s procedures and operating regulations