Seals Research at Texas A/M University

The Turbomachinery Laboratory at Texas A&M has been providing experimental data and computational codes for the design seals for many years. The program began with the development of a Halon based seal test rig. This facility provided information about the effective stiffness and damping in whirling seals. The Halon effectively simulated cryogenic fluids. Another test facility was developed (using air as the working fluid) where the stiffness and damping matrices can be determined. This data was used to develop bulk flow models of the seal's effect upon rotating machinery; in conjunction with this research, a bulk flow model for calculation of performance and rotordynamic coefficients of annular pressure seals of arbitrary non-uniform clearance for barotropic fluids such as LH2, LOX, LN2, and CH4 was developed. This program is very efficient (fast) and converges for very large eccentricities. Currently, work is being performed on a bulk flow analysis of the effects of the impeller-shroud interaction upon the stability of pumps. The data was used along with data from other researchers to develop an empirical leakage prediction code for MSFC. Presently, the flow field inside labyrinth and annular seals are being studied in detail. An advanced 3-D Doppler anemometer system is being used to measure the mean velocity and entire Reynolds stress tensor distribution throughout the seals. Concentric and statically eccentric seals were studied; presently, whirling seals are being studied. The data obtained are providing valuable information about the flow phenomena occurring inside the seals, as well as a data base for comparison with numerical predictions and for turbulence model development. A finite difference computer code was developed for solving the Reynolds averaged Navier Stokes equation inside labyrinth seals. A multi-scale k-epsilon turbulence model is currently being evaluated. A new seal geometry was designed and patented using a computer code. A large scale, 2-D seal flow visualization facility is also being developed

The influence of affect on attitude

Priests of the medieval Catholic Church understood something about the relationship between affect and attitude. To instill the proper attitude in parishioners, priests dramatized the power of liturgy to save them from Hell in a service in which the experience of darkness and fear gave way to light and familiar liturgy. These ceremonies “were written and performed so as to first arouse and then allay anxieties and fears ” (Scott, 2003, p. 227): The service usually began in the dark of night with the gothic cathedral’s nave filled with worship-pers cast into total darkness. Terrifying noises, wailing, shrieks, screams, and clanging of metal mimicked the chaos of hell, giving frightened witnesses a taste of what they could expect if they were tempted to stray. After a prolonged period of this imitation of hell, the cathedral’s interior gradually became filled with the blaze of a thousand lights. As the gloom diminished, cacophony was supplanted by the measured tones of Gregorian chants and polyphony. Light and divine order replaced darkness and chaos (R. Scott, personal correspondence, March 15, 2004). This ceremony was designed to buttress beliefs by experience and to transfigure abstractions into attitudes. In place of merely hearing about “the chaos and perdition of hell that regular performances of liturgy were designed to hold in check ” (Scott, 2003), parishioners shoul

Biochemical changes in bone in a model of weightlessness

The amounts of nonmineralized and mineralized collagen in bone from control, immobilized, and immobilized reambulated monkeys were examined. In order to understand structure function relationships of bone collagen and the reponse of a variety of conditions on control of the three dimensional structure of the collagen fibril, the stereochemistry of the cross-linking reactions as well as the stereospecific packing of the collagen molecules were studied

Inclusive Jet and Dijet Production at the Tevatron

High energy jet distributions measured since 1992 at the Fermilab Tevatron proton--antiproton collider are presented and compared to theoretical predictions. The statistical uncertainties on these measurements are significantly reduced relative to previous results. The systematic uncertainties are comparable in size to the uncertainty in the theoretical predictions. Although some discrepancies between theory and measurements are noted, the inclusive jet and dijet cross sections can be described by quantum chromodynamics. Prospects for reducing the uncertainty in the theoretical predictions by incorporating Tevatron measurements into the proton parton distributions are discussed. Dijet distributions, in excellent agreement with quantum chromodynamics, set a 2.5 TeV limit on the mass of quark constituents.Comment: 49 Pages, 33 Figures, To be published in Annual Review of Nuclear and Particle Science, Vol. 49, (1999

COST COMPARISONS OF GROCERY DEPARTMENTS IN CONVENTIONAL SUPERMARKETS AND SUPER STORES WITH IMPLICATIONS FOR TRAINING

Agribusiness,