Rotationally resolved collisional transfer rates in OH

Fluorescence lidar measurements of the hydroxyl radical require detailed information concerning collision induced processes in order to deduce the radical number density from a lidar return. The Goddard SFC OH lidar currently utilizes a broadband detector which precludes the necessity of fully understanding collisional redistribution of rotational energy within the excited state. Numerous advantages result however from the inclusion of a detector with a bandpass only slightly larger that the Doppler width of a rotational line. This however places more stringent requirements on the spectroscopy. Measurements were accordingly made of rotationally resolved quenching rates for collisions with O2, N2, and H2O. Rotational transfer rates were also measured for the same colliders. Quenching rates were measured using a Nd-YAG pumped Rh6G dye laser doubled into the UV. The OH lifetimes were measured as a function of pressure of quenching gas at total pressures of between 50 and 250 microns. Rotational transfer rates were measured by recording the emission spectrum on an intensified diode array and integrating over 10.000 laser shots

Features in the ion emission of Cu, Al, and C plasmas produced by ultrafast laser ablation

© 2015 AIP Publishing LLC. The bi-modal nature of charge integrated ion kinetic energy distributions, which result from ultrafast laser produced plasmas, is discussed in this paper. A negatively biased Faraday cup was used as a charge collector to measure ion distributions from three different solid targets that had been irradiated with an ultrafast laser in the fluence range 0.1-1 J/cm2. A bi-modal time of flight distribution is found for all three targets (C, Al, and Cu). In the case of the metallic targets (Al and Cu), high- and low-kinetic energy peaks exhibit quite different dependencies on laser fluence, whereas for the semi-metallic target (C), both peaks scale similarly with ultrafast laser fluence. The results are discussed within the framework of a one dimensional capacitor model resulting in ion acceleration

Tackifier for addition polyimides

A modification to the addition polyimide, LaRC-160, was prepared to improve tack and drape and increase prepeg out-time. The essentially solventless, high viscosity laminating resin is synthesized from low cost liquid monomers. The modified version takes advantage of a reactive, liquid plasticizer which is used in place of solvent and helps solve a major problem of maintaining good prepeg tack and drape, or the ability of the prepeg to adhere to adjacent plies and conform to a desired shape during the lay up process. This alternate solventless approach allows both longer life of the polymer prepeg and the processing of low void laminates. This approach appears to be applicable to all addition polyimide systems

The Greater Sum of Collaboration: Adding Value to Mathematics Education Through Teamwork

The role of a Mathematics Specialist can vary from pre-K through grade 8 schools. One of the most distinguishing factors involves the relationship between the Mathematics Specialists, administrators, and teachers. In this article, we share our experiences in a school culture that supports common language, collective commitments, trust, and transparency. Using this model, we have experienced high levels of teacher professionalism and student success. As lifelong learners, we continually reflect upon our practices and look for ways to meet the needs of our students. This occurs by implementing purposeful meeting structures that allow us to facilitate discussions around mathematics content, lesson planning, assessment results, and student progress. Administrators Brian Butler and Diane Kerr, along with Mathematics Specialists Tracey Hulen and Jennifer Deinhart, have formed a powerful relationship at Mason Crest Elementary School. This is a Title I school with 560 students, pre-K through grade 5, which promotes reflective practices and allows for flexibility and creativity as we continue to strengthen and improve our practices. Together, we share a story of our collaborative journey with teachers and students to create an effective mathematics program that embraces a conceptual learning philosophy. Ultimately there are two kinds of schools: learning-enriched schools and learning impoverished schools. I have yet to see a school where the learning curves ... of the adults were steeped upward and those of the students were not. Teachers and students go hand in hand as learners ... or they don\u27t go at all. [1] Roland Barth, Hand in Hand, We All Lear

Investigation of potential of differential absorption Lidar techniques for remote sensing of atmospheric pollutants

The NASA multipurpose differential absorption lidar (DIAL) system uses two high conversion efficiency dye lasers which are optically pumped by two frequency-doubled Nd:YAG lasers mounted rigidly on a supporting structure that also contains the transmitter, receiver, and data system. The DIAL system hardware design and data acquisition system are described. Timing diagrams, logic diagrams, and schematics, and the theory of operation of the control electronics are presented. Success in obtaining remote measurements of ozone profiles with an airborne systems is reported and results are analyzed

Row spacing and maturity of forage sorghum silage in north central Texas

Last updated: 10/22/201