Browsing by Author "Wiest, John M."
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Item Financial factors and institutional characteristics that relate to the long-term debt of U.S. four-year public colleges and universities(University of Alabama Libraries, 2013) Keith, Dana S.; Hardy, David E.; University of Alabama TuscaloosaDebt for public colleges and universities has been increasing while financial resources, which provide the support to repay debt, have been declining. As debt increases in proportion to assets, the risk profile of a college or university increases. This study examined the relationships between financial variables and institutional characteristics that relate to long-term debt and leverage of U.S. four-year public colleges and universities during a period of economic downturn. Understanding these relationships is needed to determine factors that enable or constrain public higher education's ability to borrow funds to meet organizational goals. In addition, this study also explored long-term debt and leverage trends categorized by Carnegie classification and geographic region from 2005 to 2009. The data for the study were obtained from IPEDS. Descriptive statistics, ANOVA, and OLS regression were used to analyze the data. The findings showed that both long-term debt and leverage of public institutions had increased from 2005 to 2009. However, leverage increased at a slower pace, which indicated that public universities were able to use existing assets to offset the increase in liabilities associated with the additional long-term debt. This study also found that differences existed in long-term debt by Carnegie classification. Doctoral/Research institutions had more long-term debt than Master's institutions, and Master's institutions had more long-term debt than Baccalaureate institutions. Although Master's institutions did not have the greatest amount of long-term debt, they had greater amounts of leverage than Doctoral/Research and Baccalaureate institutions in all fiscal years. Additionally, Master's and Doctoral/Research institutions located in the Northeast had mean leverage in all five years that exceeded recommended thresholds. The variable with the strongest relationship with long-term debt was property, plant, and equipment. Approximately 65.9% of the variance in long-term debt was explained by property, plant, and equipment. In comparison, the leverage model showed that geographic regions had the strongest relationship with leverage. Collectively, the West, Midwest, and Southeast regions accounted for 27.1% of the variance in leverage. The detailed results of the findings, conclusions, and recommendations are provided at the end of the study.Item Formation Mechanism and Composition Distribution of FePt Nanoparticles(2007-11-27) Srivastava, Chandan; Balasubramanian, Jayendra; Turner, C. Heath; Wiest, John M.; Bagaria, Hitesh G.; Thompson, Gregory B.; University of Alabama TuscaloosaSelf-assembled FePt nanoparticle arrays are candidate structures for ultrahigh density magnetic storage media. One of the factors limiting their application to this technology is particle-to-particle compositional variation. This variation will affect the A1 to L10 transformation as well as the magnetic properties of the nanoparticles. In the present study, an analysis is provided for the formation mechanism of these nanoparticles when synthesized by the superhydride reduction method. Additionally, a comparison is provided of the composition distributions of nanoparticles synthesized by the thermal decomposition of Fe(CO)5 and the reduction of FeCl2 by superhydride. The latter process produced a much narrower composition distribution. A thermodynamic analysis of the mechanism is described in terms of free energy perturbation Monte Carlo simulations.Item Making sense of safety(University of Alabama Libraries, 2016) Huey, Marcy Rayburn; Meares, Mary M.; University of Alabama TuscaloosaThe increased calls for an improved academic safety culture currently being issued by regulatory organizations outlines a very prescriptive approach to addressing safety in colleges and universities. This study focused on how academic researchers made sense of and responded to the safety programs that have been instituted by their organizations. The focus was on scientific researchers who have active research laboratories. The data was collected using semi-structured interviews and analyzed with grounded theory. The results indicated that these researchers grounded their understanding of safety and of institutional safety programs in their professional identity, developed during their own educational and early professional experiences. Further study is warranted to determine if these findings are indicative of these scientific fields across the country. This data suggested that prescriptive compliance requirements regarding safety activities would not be easily accepted by these groups if they were not consistent with this identity. While they were not overtly noncompliant, they did resist institutional safety requirements placed on them that were not in line with the social norms of their professional group. These results could lead to an altered approach towards addressing safety concerns at colleges and universities.Item Reduction of combustion noise and instabilities using porous inert material with a swirl-stabilized burner(University of Alabama Libraries, 2011) Sequera, Daniel E.; Agrawal, Ajay K.; University of Alabama TuscaloosaCombustion instabilities represent a major problem during operation of power generation systems that can lead to costly shutdown. Combustion instabilities are self excited large amplitude pressure oscillations caused by the coupling of unsteady heat release and acoustic modes of the combustor. These oscillations cause fluctuating mechanical loads and fluctuating heat transfer that can result in catastrophic premature failure of components. Combustion noise, a significant source of noise in gas turbines, can lead to combustion instabilities. Combustion noise and instabilities are different phenomena; however, they both occur due to unsteady heat release of turbulent flames that excites acoustic modes of the combustor. The instabilities self excite when flame adds energy to the acoustic field at a faster rate than it can dissipate it. Swirl-stabilized combustion and porous inert medium (PIM) combustion are two methods that have extensively been used, although independently, for flame stabilization. In this study, the two concepts are combined so that PIM serves as a passive device to mitigate combustion noise and instabilities. A PIM insert is placed within the lean premixed, swirl-stabilized combustor to affect the turbulent flow field reducing combustion noise. This study is the first step for eventual implementation in liquid fuel systems. After presenting the concept, a numerical investigation of the changes in the mean flow field caused by the PIM is presented. Changes in the flow field can be beneficial for noise reduction by optimizing the geometric parameters of the PIM. Next, atmospheric pressure experiments were conducted at low reactant inlet velocity (<10 m/s) and low reactant inlet temperature (<120 °C) to investigate effect of PIM parameters on sound pressure level (SPL), and CO and NOx emissions. Surface and interior combustion modes were identified and PIM geometric parameters were optimized. Next, a laboratory facility to conduct experiments at high reactant inlet velocity, high inlet air temperature, and high pressure was designed and developed. Results show that the porous insert substantially reduces combustion noise for a range of operating conditions. Moreover, experiments show that the porous insert can mitigate combustion instabilities without adversely affecting CO and NOx emissions.Item Wet chemical synthesis strategies to develop aluminum manganese nanoparticles for high density magnetic recording(University of Alabama Libraries, 2010) Ivie, Michael Allen; Wiest, John M.; University of Alabama TuscaloosaAs the technology era grows rapidly, there is always a need for quick access to stored data. Magnetic tape is one type of recording media used of information storage. Its main use in computer applications is for archival storage and mass storage systems. Magnetic tape is a multi-component material consisting of a base film with a top layer of magnetic particles. Particles that are used for magnetic recording devices must exhibit good magnetic properties including large coercivity and saturation magnetization. As the need for tape performance and storage capacity increases, new types of particulate media are needed to meet these demands. One candidate of particles for future magnetic tape is ferromagnetic AlMn nanoparticles. AlMn has a ferromagnetic tetragonal L10 phase which is exhibited by a class of transition metal alloy systems such as FePt, CoPt, FePd, MnPt, etc. This phase in the AlMn binary system is labeled as the τ phase and has a large anisotropy value of approximately 107 ergs/cc which translates to good magnetic properties suitable for use in magnetic tape. The advantages of producing AlMn nanoparticles for magnetic recording are the low cost and abundance of precursor materials. This dissertation investigated strategies of a solution phase chemical synthesis to produce AlMn nanoparticles. Metal nanoparticle systems are synthesized primarily by the reduction of metal salt precursors with a reducing agent in the presence of stabilizing agents in an organic solvent. Systems of metal nanoparticles with the tetragonal L10 phase characterized by high anisotropy values such as FePt and MnPt are produced via this route, and these techniques are considered as a foundation to make AlMn nanoparticles. Cyclic voltammetry experiments give the reduction potentials of Al and Mn precursors to determine suitable reducing agents. The results of the AlMn nanoparticle synthesis attempts are chronicled by the reducing agent that was used in the reaction. Different combinations of precursors, surfactants, and solvents are used in coordination with the following reducing agents: superhydride (C6H16BLi), potassium (K), hydrogen (H2), lithium aluminum hydride (LiAlH4), and sodium (Na). Also, synthesis attempts of AlMn(X) tertiary nanoparticles and core-shell AlMn nanoparticles are presented.