Multi-objective/loading optimization for rotating composite flexbeams

With the evolution of advanced composites, the feasibility of designing bearingless rotor systems for high speed, demanding maneuver envelopes, and high aircraft gross weights has become a reality. These systems eliminate the need for hinges and heavily loaded bearings by incorporating a composite flexbeam structure which accommodates flapping, lead-lag, and feathering motions by bending and twisting while reacting full blade centrifugal force. The flight characteristics of a bearingless rotor system are largely dependent on hub design, and the principal element in this type of system is the composite flexbeam. As in any hub design, trade off studies must be performed in order to optimize performance, dynamics (stability), handling qualities, and stresses. However, since the flexbeam structure is the primary component which will determine the balance of these characteristics, its design and fabrication are not straightforward. It was concluded that: pitchcase and snubber damper representations are required in the flexbeam model for proper sizing resulting from dynamic requirements; optimization is necessary for flexbeam design, since it reduces the design iteration time and results in an improved design; and inclusion of multiple flight conditions and their corresponding fatigue allowables is necessary for the optimization procedure

Mechanical Property Testing Apparatus for use in a Scanning Electron Microscope

The purpose of this design project is to develop a mechanical testing device to work in conjunction with a scanning electron microscope [SEM]. The objective of this work was to be able to perform a mechanical property measuring test and observe the small scale physical behavior of the sample with the SEM as the test progresses. The design process is presented from concept development through to the completion of the prototype device. Test data was acquired and analyzed and the results are compared to standard values for the materials being tested. Recommendations for future improvements in the next generation of the device are provided

Monstrous desires : homosexuality and the gothic in twentieth-century american literature

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal

Space acceleration measurement system triaxial sensor head error budget

The objective of the Space Acceleration Measurement System (SAMS) is to measure and record the microgravity environment for a given experiment aboard the Space Shuttle. To accomplish this, SAMS uses remote triaxial sensor heads (TSH) that can be mounted directly on or near an experiment. The errors of the TSH are reduced by calibrating it before and after each flight. The associated error budget for the calibration procedure is discussed here

A Nonclassical Dihydrogen Adduct of S = ½ Fe(I)

We have exploited the capacity of the “(SiP^(iPr)_3)Fe(I)” scaffold to accommodate additional axial ligands and characterized the mononuclear S = 1/2 H_2 adduct complex (SiP^(iPr)_3)Fe^I(H_2). EPR and ENDOR data, in the context of X-ray structural results, revealed that this complex provides a highly unusual example of an open-shell metal complex that binds dihydrogen as a ligand. The H2 ligand at 2 K dynamically reorients within the ligand-binding pocket, tunneling among the energy minima created by strong interactions with the three Fe–P bonds

A Summary Of State Laws Of Intestate Property Distribution And Succession

Property ownership patterns have a significant impact on the distribution of income, resource returns and wealth. Although ownership patterns are commonly altered by sales and purchases of property in the resource markets, the acquisition of property through gifts and inheritances also has an important influence on property ownership and transfer

Modal Analysis and Vibration Test of NASA MSFC Shaker Table

A shaker can be used to simulate launch vibrations and check responses of structures forced at different frequencies. When vibrating at certain frequencies during tests, structural modes of the shaker table itself can cause the test to abort by accelerating too much or by pushing too much electrical gain through the system. Furthermore, structural modes can produce misleading data at these modal frequencies and cause the test article to be under-tested or over-tested. A modal roving hammer test of the horizontal shaker table is conducted to characterize these modes of the shaker table. Two cases were tested in an attempt to simulate the boundary condition of the table on the shaker: free-free and free-fixed. The free-free case revealed a stretching mode at 1334.2Hz while free-fixed showed two stretching modes at 576.7Hz and 1372.3Hz. A subsequent vibration test revealed controlling 20in from the shaker attachment point best controls these modes without drastically over-testing or under-testing

Magnesium depletion triggers production of an immune modulating diterpenoid in Mycobacterium tuberculosis

Mycobacterium tuberculosis (Mtb) is the causative agent of the human disease Tuberculosis, and remains a worldwide health threat responsible for ~1.7 million deaths annually. During infection, Mtb prevents acidification of the engulfing phagosome, thus blocking endocytic progression and eventually leading to stable residence. The diterpenoid metabolite isotuberculosinol (isoTb) exhibits biological activity indicative of a role in this early arrest of phagosome maturation. Presumably, isoTb production should be induced by phagosomal entry. However, the relevant enzymatic genes are not transcriptionally upregulated during engulfment. Previous examination of the initial biosynthetic enzyme (Rv3377c/MtHPS) involved in isoTb biosynthesis revealed striking inhibition by its Mg2+ co-factor, leading to the hypothesis that the depletion of Mg2+ observed upon phagosomal engulfment may act to trigger isoTb biosynthesis. While Mtb is typically grown in relatively high levels of Mg2+ (0.43 mM), shifting Mtb to media with phagosomal levels (0.1 mM) led to a significant (~10-fold) increase in accumulation of the MtHPS product, halimadienyl diphosphate, as well as easily detectable amounts of the derived bioactive isoTb. These results demonstrate isoTb production by Mtb specifically under conditions that mimic phagosomal cation concentrations, and further support a role for isoTb in the Mtb infection process