Saturation of atomic transitions using sub-wavelength diameter tapered optical fibers in rubidium vapor

We experimentally investigate ultralow-power saturation of the rubidium D2 transitions using a tapered optical fiber (TOF) suspended in a warm Rb vapor. A direct comparison of power-dependent absorption measurements for the TOF system with those obtained in a standard free-space vapor cell system highlights the differences in saturation behavior for the two systems. The effects of hyperfine pumping in the TOF system are found to be minimized due to the short atomic transit times through the highly confined evanescent optical mode guided by the TOF. The TOF system data is well-fit by a relatively simple empirical absorption model that indicates nanoWatt-level saturation powers.Comment: 6 pages, 6 figure

Experimental and theoretical aerodynamic characteristics of two hypersonic cruise aircraft concepts at Mach numbers of 2.96, 3.96, and 4.63

The longitudinal and lateral directional aerodynamic characteristics for two Mach 5 cruise aircraft concepts were determined for test Mach numbers of 2.96, 3.96, and 4.63. Estimates from hypersonic impact theory and first order supersonic linearized theory were compared with data to indicate the usefulness of these methods. The method which applied tangent cone empirical theory to the body and tangent wedge theory to the wings and to the horizontal and vertical tails provided the best estimates. The tangent cone empirical theory applied to all components showed poor agreement with data, and the linear theory estimates were accurate only for lift coefficient and drag coefficient at low angles of attack

Evaluation of a low-density polyimide foam in a dynamic, high temperature environment

A low density polyimide foam material was tested in an arc tunnel to determine its potential for heat shield application on aerospace vehicles. The results show that the material has some reuse potential at surface temperatures as high as 750 K. When a black refractory paint was applied to the surface of the material, the surface recession was negligible at 750 K. An analytical thermal conductivity was derived for this material which, combined with measured thermal property values, can be used to make preliminary design thickness calculations for heat shield applications

Surface recession characteristics of a cryogenic insulation subjected to arc-tunnel heating

Specimens of a cryogenic insulation, proposed for use on the space shuttle external tank, were tested in an arc tunnel over a range of heating rates, pressures, and enthalpies corresponding to the shuttle ascent environment. A regression analysis was used to correlate the test data. Correlation equations involving surface recession rate as a function of heating rate, pressure, and enthalpy were developed. These equations can be used to make total surface recession predictions for shuttle ascent flight environments

Analytical determination of the effect of thermal property variations on the performance of a charring ablator

Effects of thermal-property variations on performance of charring ablato

Effects of aerobic exercise training on diaphragm muscle metabolism in a rat model of Pulmonary Arterial Hypertension

poster abstractPulmonary arterial hypertension (PAH) is characterized by a progressive increase in pulmonary vascular resistance that leads to right ventricular (RV) overload and eventually RV failure and death. PAH is associated with diaphragm muscle dysfunction and increased work of breathing which contributes to the exercise intolerance that is hallmark in this patient population. Our lab and others have described a shift in substrate utilization toward non-oxidative (glycolytic) metabolism in the RV and skeletal muscle of PAH rodent models as well as in patients. This project will determine if ‘glycolytic shift’ also occurs in the diaphragm muscle which may contribute to exercise intolerance and dyspnea. Since regular aerobic exercise is well-known to promote adaptations enhancing oxidative metabolism in cardiac muscle and skeletal muscle of the extremities, this project will also investigate the impact of exercise training on diaphragm muscle metabolism. Diaphragm muscles were harvested upon completion of a 6 week, 4x/wk. treadmill training program that consisted of 60 min runs at a relative intensity of 50% of aerobic capacity (VO2max). Abundance of glucose transporter Glut-1, a marker of glycolytic metabolism, is being evaluated by Immunoflourescent (IF) staining at the cell membrane of diaphragm myocytes. We expect to find that PAH rats have greater abundance of diaphragm Glut-1 and that exercise training at least partially ameliorates this PAH-induced ‘glycolytic shift’

Bulletin No. 271 - Fertility Maintenance by Rotation and Manure

For several years there has been maintained on the Greenville Farm of the Utah Experiment Station an experiment to determine the relative value of different cropping systems and manurial treatments in maintaining the fertility of the soil

Bulletin No. 188 - Maintaining the Productivity of Irrigated Land

It is almost universal history that in farming a newly developed region no attention whatever is paid to maintaining the fertility of the soil. This is natural for two very obvious reasons. In the first place the pioneer has other and more pressing problems in the subduing of the new land, and in the second place such virgin soils are generally blessed with a great abundance of native fertility. New lands in an arid or semiarid region are usually especially fertile because they represent a long-time accumulation of fertility which is not possible under humid conditions. Since in a humid region the tendency for evaporation is not sufficient to remove all of the water that goes into the soil, there is always a certain excess that seeps downward to the water-table and is later removed by springs and rivers. This seep water constantly carries away a certain amount of the soluble salts that serve as food for plants. In an arid climate, on the other hand, the evaporating tendency is more than sufficient to remove all the water that goes into the soil so that the ultimate movement of the soil moisture is upward. This soil moisture leaves all its soluble material at the surface as it evaporates, and thus there is an accumulation of mineral plant-food. (This accumulation of soluble material at the surface may become excessive, in which case we have alkali -but that is another problem.) On the other hand, the organic matter or humus of the soil contains most of the nitrogen (one of the most important plant-foods), and this does not move with the water but rather is lost by slow oxidation or burning up, so that this element of plant-food is lost more rapidly from the well-aerated soils of the arid region than from soils in a humid climate