The NCAR Airborne Infrared Lidar System (NAILS)

A planned airborne lidar system is presented which is intended to provide a remote sensing facility for a variety of applications. The eventual goal of the system development is a Doppler wind measurement capability for boundary layer dynamics and cloud physics applications. The first stage of development is focused initially on a direct detection lidar to measure aerosol profiles and depolarization from cloud backscatter. Because of the Doppler goal, interest in larger particles to define the top of the mixed layer, and eye safety, the first stage of the system is based on a pulsed CO2 laser. A compact, relatively simple and inexpensive system that achieves flexibility to meet the data requirements of a variety of investigators by being easily modified rather than having many different capabilities built in is the goal. Although the direct detection sensitivity is less than that for heterodyne detection, the simpler system allows the achievement of useful scientific results and operating experience towards more complex lidars while staying within budget and time constraints

Modeling, designing and simulating a pointing control system for balloon-borne solar experiments

A simplified model of a pointing control system for balloon-borne solar experiments is chosen. Equations of motion for this model are derived and a feedback control law is defined. A digital computer simulation of the system is developed. Simulation results show favorable system response characteristics

Interview with Kathleen Lightsey

https://digitalcommons.winthrop.edu/scmotheroftheyear/1028/thumbnail.jp

A nonlinear estimator for reconstructing the angular velocity of a spacecraft without rate gyros

A scheme for estimating the angular velocity of a spacecraft without rate gyros is presented. It is based upon a nonlinear estimator whose inputs are measured inertial vectors and their calculated time derivatives relative to vehicle axes. It works for all spacecraft attitudes and requires no knowledge of attitude. It can use measurements from a variety of onboard sensors like Sun sensors, star trackers, or magnetometers, and in concert. It can also use look angle measurements from onboard tracking antennas for tracking and data relay satellites or global positioning system satellites. In this paper, it is applied to a Sun point scheme on the Hubble Space Telescope assuming all or most of its onboard rate gyros have failed. Simulation results are presented for verification

Preparation of polyimides from mixtures of monomeric diamines and esters of polycarboxylic acids

Polyimides having high thermal and oxidative stability are prepared by the reaction of a mixture of monomers comprising (1) a dialkyl or tetraalkyl ester of an aromatic tetracarboxylic acid; (2) an aromatic diamine; and (3) a monoalkyl or dialkyl ester of a dicarboxylic acid where in the ratio of a:b:c is n:(n+1):2, wherein n has a value from 1 to 20. The mixture of monomers is prepared in a 30 to 70 percent by weight solution of an organic solvent, a substrate impregnated with the solution and heated at 50 to 205 C to remove said solvent and form a low molecular weight prepolymer, and thereafter heated at 275 to 350 C to cure to a high molecular weight polyimide

Thermally stable polyimides from solutions of monomeric reactants

Monomer solutions have high solubility and low solution viscosity. Since monomers are shipped in powder form and reaction to polyimide-acid prepolymer is omitted, the cost is low and handling is easy

Neurometabolism and cognitive functioning in healthy children : a proton magnetic resonance spectroscopy study

This study investigated the role of sex, mean NAA/Cr and Cho/Cr, and variability in these metabolites in predicting memory and processing speed. This study utilized predictive models including sex, mean ratios of NAA/Cr and Cho/Cr, as well as the standard deviation of these ratios, within tissue type, among voxels in a supraventricular slice. In addition, models included interaction terms between each neurometabolic variable and sex. Tests of memory and processing speed were then regressed in a three-step hierarchical regression onto sex, main effects for neurometabolites, and interaction effects. The regression of memory was significant in the model including interaction terms, and showed higher mean NAA/Cr and lower standard deviation of NAA/Cr in gray matter related to better memory performance in boys, with the reverse pattern in girls. Lower standard deviation of NAA/Cr in the white matter was related to faster processing speed for both sexes. A model including sex, Cho/Cr mean and standard deviation by tissue type, and sex by Cho/Cr interactions significantly predicted memory performance. No model using Cho/Cr predicted processing speed. Posthoc analyses suggest that tests of working memory showed stronger relationships to metabolites than tests of learning. Moreover, relationships may differ by sex depending on whether digit span or spatial span is the working memory variable of interest