Fiber-reinforced ceramic composites for Earth-to-orbit rocket engine turbines

Fiber reinforced ceramic matrix composites (FRCMC) are emerging materials systems that offer potential for use in liquid rocket engines. Advantages of these materials in rocket engine turbomachinery include performance gain due to higher turbine inlet temperature, reduced launch costs, reduced maintenance with associated cost benefits, and reduced weight. This program was initiated to assess the state of FRCMC development and to propose a plan for their implementation into liquid rocket engine turbomachinery. A complete range of FRCMC materials was investigated relative to their development status and feasibility for use in the hot gas path of earth-to-orbit rocket engine turbomachinery. Of the candidate systems, carbon fiber-reinforced silicon carbide (C/SiC) offers the greatest near-term potential. Critical hot gas path components were identified, and the first stage inlet nozzle and turbine rotor of the fuel turbopump for the liquid oxygen/hydrogen Space Transportation Main Engine (STME) were selected for conceptual design and analysis. The critical issues associated with the use of FRCMC were identified. Turbine blades were designed, analyzed and fabricated. The Technology Development Plan, completed as Task 5 of this program, provides a course of action for resolution of these issues

Evaluation of different signal processing options in unilateral and bilateral Cochlear Freedom recipients using R-Space background noise

Understanding speech in the presence of noise is a difficult task for cochlear implant patients. This study examines the real-world effectiveness of different signal processing approaches available in the Cochlear Nucleus Freedom device to enhance speech perception in noise for cochlear implant recipients

Essays on business taxation and development

This thesis addresses a number of questions on the optimal taxation of firms, with particular emphasis on the challenges to taxation in developing economies. Chapter 1 exploits bunching of firms at a tax kink to identify the effect of a tax rate change on investment. Building on the standard bunching framework, I estimate the frequency distribution of firms around the kink, and the share of bunching firms with excess investment. I apply this approach to administrative tax returns for firms in the United Kingdom and find that excess investment explains up to 20% of bunch ing. Chapter 2 examines the trade-off between production efficiency and revenue efficiency in taxation under imperfect enforcement. We exploit quasi-experimental variation created by a minimum tax scheme, a production inefficient policy used in many developing countries, which consists of taxing firms on turnover as their profit rate falls below a certain threshold. Using administrative tax records of corporations in Pakistan, we find large bunching around the profit rate kink createded by the minimum tax scheme and estimate that the turnover tax reduces evasion by up to 60-70% of corporate income. Chapter 3 analyzes the impact of interventions by the International Monetary Fund (IMF) on countries’ likelihood of adopting the value added tax (VAT). I discuss how the IMF has promoted VAT adoption by making lending conditional on adoption, providing administrative and technical assistance, and reducing the political costs of adoption. Applying a Cox proportional hazard model to a cross-country panel for the period 1975-2000, I find that countries that are under a lending agreement with the IMF are three times as likely to adopt the VAT than are countries not under a lending agreement

Changes Towards Internal Locus of Control as a Function of Improving Time Management Skills

Locus of Control (LOC) refers to the generalized expectancy that one controls the events in his/her life (internal orientation) or that events are controlled by other forces, such as luck (external orientation). According to many reviews of the extensive LOC literature, it is beneficial to have an internal rather than an external orientation. For example, desirable characteristics such as personal adjustment, high self-esteem, good job performance and job satisfaction are associated with internal LOC. This study was undertaken to identify and test a model which could be of use in an organizational setting for promoting the belief in internal control. A time management training model was chosen on the assumption that people who learn to manage their time better would feel more in control of their lives. The 67 University of Central Florida students who accepted the free Daytimers (a widely used professional time management system) and completed the pretest and posttest questionnaires served as the sample. The questionnaires in Rotter\u27s LOC scale and a time management skills scale, and were administered at the beginning and end of the Spring semester. The Daytimers were distributed immediately after the pretest. Students who made frequent use of the Daytimers improved their time management skills and became more internal by the end of the semester. There were no corresponding significant changes in either time management skills or LOC for students who used the Daytimers infrequently. These results suggest that time management training can be used to promote the belief in internal control. Future research is recommended to verify the expectations that these changes in LOC will result in better personal adjustment, greater job performance and more job satisfaction

Regulation of Securities Offerings In California: Is It Time For a Change After a Century of Merit Regulation?

The California securities law originated in 1913 from a populist movement that embodied a paternalistic attitude toward the protection of investors. It was characterized by the registration of offerings of securities with few exemptions and exclusions, a qualitative review of the merits of those offerings and an administrator with broad authority to implement and enforce the law. While the California securities law is still based on merit review, exclusions and exemptions have been added and expanded over the years by the California legislature and securities regulators. More recently, Congress has preempted state registration and merit review of various securities and transactions and this has been implemented and expanded by administrative action. These developments raise a question as to whether it is time to consider a change in the method of regulating securities offerings in California and, in that connection, to determine whether the system of merit review has outgrown any usefulness it may have had originally. In my view, addressing this issue requires an empirical analysis of the regulation of securities offerings in California and its evolution over the past century. The analysis begins in Part II with an overview of the history of the California securities law focused on issuer transactions from 1913 to the comprehensive revision of the law in 1968. This is followed in Part III by a more in-depth review and chronology of changes in the law and practice from 1917 to the present pertaining to each of three types of issuer transactions: private stock offerings, real estate syndications, and public stock offerings. Included are developments in the federal securities law and actions taken by self-regulatory organizations that have had an impact on the regulation of these transactions in California. To put this in perspective, the review of each type of issuer transaction is preceded by a brief history of capital formation pertaining to that transaction. Part IV presents data showing the number and types of securities offerings in California for which notices of exemption or applications for qualification by coordination, notification or permit have been filed with the Department. With this background, the rationale for revisiting the method of regulating the offer and sale of securities and the system of merit review in California is set forth in Part V. In conclusion, I believe it is time to change the method of regulating the offer and sale of securities in California in a manner that would include eliminating or limiting the system of merit review, with a view to enhancing the antifraud enforcement of the California securities law. Several courses of action are explored to accomplish that result

Sudbury project (University of Muenster-Ontario Geological Survey): Sr-Nd in heterolithic breccias and gabbroic dikes

One major objective of our Sudbury project was to define origin and age of the huge breccia units below and above the Sudbury Igneous Complex (SIC). The heterolithic Footwall Breccia (FB) represents a part of the uplifted crater floor. It contains subrounded fragments up to several meters in size and lithic fragments with shock features (greater than 10 GPa) embedded into a fine- to medium-grained matrix. Epsilon(sub Nd)-epsilon(sub Sr) relationships point to almost exclusively parautochthonous precursor lithologies. The different textures of the matrix reflect the metamorphic history of the breccia layer; thermal annealing by the overlying hot impact melt sheet (SIC) at temperatures greater than 1000 C resulted in melting of the fine crushed material, followed by an episode of metasomatic K-feldspar growth and, finally, formation of low-grade minerals such as actinolite and chlorite. Isotope relationships in the Onaping breccias (Gray and Green Member) are much more complex. All attempts to date the breccia formation failed: Zircons are entirely derived from country rocks and lack the pronounced Pb loss caused by the heat of the slowly cooling impact melt sheet (SIC). Rb-Sr techniques using either lithic fragments of different shock stages or the thin slab method, set time limits for the apparently pervasive alkali mobility in these suevitic breccias. The data array and the intercept in the plots point to a major Rb-Sr fractionation around 1.54 Ga ago. This model age is in the same range as the age obtained for the metasomatic matrix of the FB. Rb-Sr dating of a shock event in impact-related breccias seems to be possible only if their matrix had suffered total melting by the hot melt sheet (FB) or if they contain a high fraction of impact melt (suevitic Onaping breccias), whereas the degree of shock metamorphism in rock or lithic fragments plays a minor role. In the Sudbury case, however, the impact melt in the seuvitic breccias is devitrified and recrystallized, which changed Rb/Sr ratios quite drastically. Therefore, the Onaping breccias give only age limits for alteration and low-grade metamorphism. The Sm-Nd system was not reset during the Sudbury event; clasts as well as the matrix in the FB and in the Onaping breccias show preimpact 'Archean' Nd isotope signatures

Indian River Lagoon surface water improvement and management (SWIM) plan, 2002 update.

In recognition of the need to place additional emphasis on the restoration, protection, and management of the surface water resources of the state, the Florida Legislature, through the Surface Water Improvement and Management (SWIM) Act of 1987, directed the state’s water management districts to “design and implement plans and programs for the improvement and management of surface water” (Section 373.451, Florida Statutes [FS]). The SWIM legislation requires the water management districts to protect the ecological, aesthetic, recreational, and economic value of the state’s surface water bodies, keeping in mind that water quality degradation is frequently caused by point and nonpoint source pollution and that degraded water quality can cause both direct and indirect losses of aquatic habitats. This 2002 update is the second update of the Indian River Lagoon SWIM Plan. This 2002 plan update includes a status report on the state of the Lagoon, a summary of progress on projects undertaken since the last update, and recommendations for future projects and other actions over the next 5 years. (262pp.