A comparative analysis of the decoupling effects in a magnetic forming beryllium coil assembly

Digital computer for determining currents and forces in magnetic forming beryllium coil assembl

Formulas establish audio range inductance in beryllium coils

Mathematical modeling is used to determine the effects of resistance and capacitance upon the audio-inductance range of beryllium hammer coils and beryllium nylon-potted coils

An investigation of the decoupling effects in a magnetic forming beryllium coil assembly

Decoupling effects in magnetic forming beryllium coil assembl

A Correlation Study of Second Destination Transportation Funding and Vehicle Movement

HQ AFMC has consistently experienced problems with the Second Destination Transportation budget being under funded. This under funding causes the command to implement control actions on how funds are allocated to ensure that enough funds are available. This research effort was intended to show the relationship between spending restrictions and how vehicles move between theaters. By identifying whether or not and how the control actions on Second Destination Transportation funding affects inter-theater vehicle movement capabilities, this research seeks to assist those decision makers in making fully informed decisions when allocating scare fiscal resources. The results of this research indicate that there is not a correlation between spending restrictions and vehicle movement. While the research did not show a correlation, it does not necessarily mean that it does not exist

Structural and functional characterization of Rtf1 and insight into its role in transcriptional regulation

Originally discovered in a search for RNA polymerase II-associated factors, the Paf1 complex (Paf1C) is best characterized for its roles in regulating transcription elongation. The complex co-localizes with RNA polymerase II from the promoter to the 3’ end of genes and has been linked to a growing list of transcription-related processes including: elongation through chromatin, histone modifications, and recruitment of factors important in transcript maturation. The complex is conserved throughout eukaryotes and is comprised of the proteins Paf1, Ctr9, Cdc73, Rtf1, and Leo1. The domain structures of Paf1C subunits are largely undefined and have few clear homologs, making it difficult to postulate for or localize functions to the individual subunits. To understand mechanistically how Paf1C coordinates its functions and interactions, I took an approach utilizing biochemical, biophysical, and structural techniques to characterize proteins within Paf1C, specifically focusing on the Rtf1 subunit. The goal of my thesis work was to determine the molecular mechanism by which Rtf1 influences transcription and chromatin structure. To this end I focused on studying different functional domains within Rtf1. I provided a molecular description of how Rtf1 mediates Paf1C recruitment to elongating RNA polymerase II. Recruitment of Rtf1 is controlled by its centrally located Plus3 domain and a direct interaction with the conserved elongation factor Spt5. I solved the co-crystal structure of the human Plus3 domain bound to a phosphorylated C-terminal repeat of Spt5. The structure revealed the basis for recognition of the repeat motif of Spt5, an important component in the recruitment of regulatory factors to RNA polymerase II. I have performed further structural characterization of Rtf1, studying the N-terminal histone modification domain. To gain insight into the molecular mechanism underlying the domain’s function, I successfully crystallized and solved the structure of a minimal region of Rtf1 that is necessary and sufficient for Rtf1-mediated histone modifications. The structure, paired with conservation analysis and genetic phenotype data, have allowed us to identify important surfaces on Rtf1 that function in regulating chromatin structure. Taken together these studies shed new light onto the mechanism by which Paf1C influences the complex network of regulatory interactions required for eukaryotic transcription

A study of intense magnetic fields for high energy forming and structural assembly Interim report

Determination of maximum force on static sheet of aluminum subjected to magnetic field of hammer coi

Development of a valid mathematical formula or group of formulas to establish within an accuracy of 5 percent the inductance audio range resulting in beryllium coil assemblies Final report

Mathematical formulas to determine net inductance in audio range of both hammer coil and cryogenic sealing coi

Long-Term Outcomes of an Abstinence-Based, Small-Group Pregnancy Prevention Program in New York City Schools

Context: Despite drops in U.S. teenage birthrates, questions continue to arise about how best to reduce the country\u27s adolescent birthrate. School-based programs continue to be considered one of the best ways to reach adolescents at risk of early sexual activity. Methods: A total of 312 students completed a pretest, a posttest and a follow-up one year after the posttest: 125 who had participated in a 3-4-month-long abstinence-based small-group intervention led by trained social workers, and 187 in a comparison group that received no special services. Results: There were few significant differences between the intervention and comparison groups at posttest. At the one-year follow-up, however, intervention students had significantly better scores on locus of control, their relationship with their parents and (among males only) their attitudes about the appropriateness of teenage sex. Measures of depression, self-esteem, intentions to have sex, attitudes toward teenage pregnancy and various behaviors did not differ significantly between groups. By the time of the one-year follow-up, there was no difference between study groups among females in the initiation of sexual intercourse. Among the males, initiation of sexual intercourse appeared to be higher in the intervention group than in the comparison group, but the difference was not statistically significant. Positive outcomes were especially limited among students who were already sexually active at the start of the study, a finding that emphasizes the difficulties of reaching adolescents who are already at high risk for pregnancy. Conclusions: A small-group abstinence-based intervention focusing on mental health can have some impact on adolescents\u27 attitudes and relationships (particularly with their parents). Long-term evaluations are important for determining the effects of an intervention, as it is difficult to change adolescent risk behavior

Active Damping Using Distributed Anisotropic Actuators

A helicopter structure experiences substantial high-frequency mechanical excitation from powertrain components such as gearboxes and drive shafts. The resulting structure-borne vibration excites the windows which then radiate sound into the passenger cabin. In many cases the radiated sound power can be reduced by adding damping. This can be accomplished using passive or active approaches. Passive treatments such as constrained layer damping tend to reduce window transparency. Therefore this paper focuses on an active approach utilizing compact decentralized control units distributed around the perimeter of the window. Each control unit consists of a triangularly shaped piezoelectric actuator, a miniature accelerometer, and analog electronics. Earlier work has shown that this type of system can increase damping up to approximately 1 kHz. However at higher frequencies the mismatch between the distributed actuator and the point sensor caused control spillover. This paper describes new anisotropic actuators that can be used to improve the bandwidth of the control system. The anisotropic actuators are composed of piezoelectric material sandwiched between interdigitated electrodes, which enables the application of the electric field in a preferred in-plane direction. When shaped correctly the anisotropic actuators outperform traditional isotropic actuators by reducing the mismatch between the distributed actuator and point sensor at high frequencies. Testing performed on a Plexiglas panel, representative of a helicopter window, shows that the control units can increase damping at low frequencies. However high frequency performance was still limited due to the flexible boundary conditions present on the test structure

Coupled dynamics of voltage and calcium in paced cardiac cells

We investigate numerically and analytically the coupled dynamics of transmembrane voltage and intracellular calcium cycling in paced cardiac cells using a detailed physiological model and its reduction to a three-dimensional discrete map. The results provide a theoretical framework to interpret various experimentally observed modes of instability ranging from electromechanically concordant and discordant alternans to quasiperiodic oscillations of voltage and calcium