Efficiency in education

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Development, simulation validation, and wind tunnel testing of a digital controller system for flutter suppression

Flutter suppression (FS) is one of the active control concepts being investigated by the AFW program. The design goal for FS control laws was to increase the passive flutter dynamic pressure by 30 percent. In order to meet this goal, the FS control laws had to be capable of suppressing both symmetric and antisymmetric flutter instabilities simultaneously. In addition, the FS control laws had to be practical and low-order, robust and capable of real time execution within the 200 hz. sampling time. The purpose here is to present an overview of the development, simulation validation, and wind tunnel testing of a digital controller system for flutter suppression

Development of Biologically Based Therapies for Basal-like Breast Tumors

There have been many experiments on breast cancer cell lines and tumors with respect to identifying genes/pathways that are involved in cancer initiation, progression and response to therapy; however, only a few actually make suggestions that might affect treatment. The knowledge that breast cancer actually represents several diseases that arise from at least two different epithelial cells has been a major stepping-stone for stratifying patients and identifying more selective and biology-based therapies. Drugs aimed at the estrogen receptor, estrogen production, and HER2 have been very successful in the many patients whose tumors are dependent upon these signaling pathways for growth. Unfortunately for tumors that lack these markers, such as basal-like subtype, there are few treatment options. Until recently, few studies had actually considered if there were subtype-specific differences in response to chemotherapy. This dissertation focuses on the basal-like subtype of cancer and examines responses to chemotherapeutics relative to the luminal subtypes and evaluates the EGFR pathway as a place for potential therapeutic intervention. In response to two chemotherapeutics - doxorubicin and 5-fluorouracil - a general stress response was the dominant profile and this profile varied both in vitro and in vivo between the subtypes. The drug-specific response was more similar in the subtypes. A predictive gene list was identified that could predict both subtype and drug treatment with fairly high accuracy suggesting some degree of subtype-specific mechanism of action. The different responses to doxorubicin and 5-fluorouracil led us to evaluate sensitivity to a larger panel of drugs and cell lines and we determined that the basal-like subtype was more sensitive to carboplatin. While identification of chemotherapy regimens that are beneficial to the basal-like subtype is needed, drugs targeted to specific deregulated pathways in this subtype will be more effective in the long run. My work evaluated the EGFR pathway and determined it is high in 90% of all basal-like tumors, but I also identified high expression of genes downstream of EGFR that can induce EGFR-independent activation of this pathway. My data suggest that inhibition of MEK or PI3K, along with chemotherapeutics, may be an effective regimen for basal-like patients

Regional Strucutal Cross Sections, Mid-Permian to Quaternary Strata, Texas Panhandle and Eastern New Mexico

The Palo Duro and Dalhart Basins of the Texas Panhandle and eastern New Mexico contain bedded Permian salts of sufficient thickness and depth to be considered potential sites for long-term storage and isolation of high-level nuclear waste. Salt (primarily halite) is a desirable host rock because of its low permeability, high thermal conductivity, low moisture content, and high gamma-ray shielding properties (Johnson, 1976b). A major concern that must be addressed if nuclear waste is to be stored in the Texas Panhandle is the long-term integrity of the bedded-salt host rock. Areas where salt has been removed by dissolution have been identified beneath the Southern High Plains, along the eastern and western escarpments of the Southern High Plains, and along the Canadian River valley (Gustavson and others, 1980b; Presley, 1980a, 1980b). Region I cross sections of mid-Permian to Quaternary strata in the Texas Panhandle and eastern New Mexico illustrate lithologic and structural relations that are interpreted to have resulted from the regional dissolution of salt and the collapse of overlying strata. The cross sections were constructed using gamma-ray logs, sample logs, and surface geologic maps (Handford, 1980a; McGillis, 1980). Gamma-ray logs are shown on the cross sections because they best demonstrate variations in evaporite strata. Figure 1 is an index map depicting the locations of the cross sections. Stratigraphic nomenclature used on the cross sections is given in table 1.Bureau of Economic Geolog

Digital-flutter-suppression-system investigations for the active flexible wing wind-tunnel model

Active flutter suppression control laws were designed, implemented, and tested on an aeroelastically-scaled wind tunnel model in the NASA Langley Transonic Dynamics Tunnel. One of the control laws was successful in stabilizing the model while the dynamic pressure was increased to 24 percent greater than the measured open-loop flutter boundary. Other accomplishments included the design, implementation, and successful operation of a one-of-a-kind digital controller, the design and use of two simulation methods to support the project, and the development and successful use of a methodology for on-line controller performance evaluation