Compton scatter attenuation gamma ray spectrometer

A gamma ray spectrometer is described for use in intense radiation fields such as those in the vicinity of a rocket engine exhaust. A collimated radiation beam is Compton scattered toward shielded spectrometers to reduce the energy and intensity of the radiation and is energy selective among the spectrometers. The scattering targets are changeable to control the percentage of the radiation scattered. Sum-Compton coincidence techniques are employed for data selection

Autumn Storms Trigger Enhanced Export of Iron, Phosphorus, and Carbon from a Forested Vermont Catchment

Autumn leaf fall may be an important driver of annual stream loading in forested catchments due to the introduction of large amounts of labile organic matter. In light of climate change projections for an intensification of the autumnal hydrological cycle for northern temperate forests, there is an increasing demand to understand this leaf fall period, and the extent to which it may drive water quality. In this study, we examine the export and biogeochemical coupling of dissolved organic carbon (DOC), iron (Fe), aluminum (Al), and phosphorus (P) during autumn and summer storms to understand the effects of seasonality and storm timing and magnitude on stream loading dynamics. We utilize in situ spectrophotometric sensors to measure UV-Vis light absorbance with high temporal resolution in order to quantify rapid changes in stream chemistry during storm events. We also explore the potential to project concentrations of the aforementioned parameters using partial least squares regression (PLSR) and high frequency absorbance data. Post leaf fall autumn storms resulted in the export of 23% of total study DOC in a 2-week period, as well as the largest fluxes of Fe and Al observed over the study period. These results may have important implications for nutrient loading in the receiving water body, Lake Champlain

Cargo launch vehicles to low earth orbit

There are two primary space transportation capabilities required to support both base programs and expanded mission requirements: earth-to-orbit (ETO) transportation systems and space transfer vehicle systems. Existing and new ETO vehicles required to support mission requirements, and planned robotic missions, along with currently planned ETO vehicles are provided. Lunar outposts, Mars' outposts, base and expanded model, ETO vehicles, advanced avionics technologies, expert systems, network architecture and operations systems, and technology transfer are discussed

COMMUNITY DEVELOPMENT--MID-COAST MAINE

Community/Rural/Urban Development,

Ground resonance analysis using a substructure modeling approach

A convenient and versatile procedure for modeling and analyzing ground resonance phenomena is described and illustrated. A computer program is used which dynamically couples differential equations with nonlinear and time dependent coefficients. Each set of differential equations may represent a component such as a rotor, fuselage, landing gear, or a failed damper. Arbitrary combinations of such components may be formulated into a model of a system. When the coupled equations are formed, a procedure is executed which uses a Floquet analysis to determine the stability of the system. Illustrations of the use of the procedures along with the numerical examples are presented

Laboratory Quality Control Report: Why is it Important?

The Arkansas Water Resources Center (AWRC) maintains a fee-based water quality lab that is certified through the Arkansas Department of Environmental Quality (ADEQ). The AWRC Water Quality Lab analyzes water samples for a variety of constituents, using standard methods for the analysis of water samples (APHA 2012). Whether you have one or several water samples tested, the lab generates a report of values for each parameter that you have analyzed, which is provided to the client. Included with every water quality report is a Lab Quality Control (QC) report for each of the parameters analyzed within the package. The Lab QC report provides important information about the performance of the methods used to test your water sample(s)

Formal Contexts, Formal Concept Analysis, and Galois Connections

Formal concept analysis (FCA) is built on a special type of Galois connections called polarities. We present new results in formal concept analysis and in Galois connections by presenting new Galois connection results and then applying these to formal concept analysis. We also approach FCA from the perspective of collections of formal contexts. Usually, when doing FCA, a formal context is fixed. We are interested in comparing formal contexts and asking what criteria should be used when determining when one formal context is better than another formal context. Interestingly, we address this issue by studying sets of polarities.Comment: In Proceedings Festschrift for Dave Schmidt, arXiv:1309.455

Comprehensive rotorcraft analysis methods

The development and application of comprehensive rotorcraft analysis methods in the field of rotorcraft technology are described. These large scale analyses and the resulting computer programs are intended to treat the complex aeromechanical phenomena that describe the behavior of rotorcraft. They may be used to predict rotor aerodynamics, acoustic, performance, stability and control, handling qualities, loads and vibrations, structures, dynamics, and aeroelastic stability characteristics for a variety of applications including research, preliminary and detail design, and evaluation and treatment of field problems. The principal comprehensive methods developed or under development in recent years and generally available to the rotorcraft community because of US Army Aviation Research and Technology Activity (ARTA) sponsorship of all or part of the software systems are the Rotorcraft Flight Simulation (C81), Dynamic System Coupler (DYSCO), Coupled Rotor/Airframe Vibration Analysis Program (SIMVIB), Comprehensive Analytical Model of Rotorcraft Aerodynamics and Dynamics (CAMRAD), General Rotorcraft Aeromechanical Stability Program (GRASP), and Second Generation Comprehensive Helicopter Analysis System (2GCHAS)

Simulation of meteorological satellite (METSAT) data using LANDSAT data

The information content which can be expected from the advanced very high resolution radiometer system, AVHRR, on the NOAA-6 satellite was assessed, and systematic techniques of data interpretation for use with meteorological satellite data were defined. In-house data from LANDSAT 2 and 3 were used to simulate the spatial, spectral, and sampling methods of the NOAA-6 satellite data

Analytical Model for the Impulse of Single-Cycle Pulse Detonation Tube

An analytical model for the impulse of a single-cycle pulse detonation tube has been developed and validated against experimental data. The model is based on the pressure history at the thrust surface of the detonation tube. The pressure history is modeled by a constant pressure portion, followed by a decay due to gas expansion out of the tube. The duration and amplitude of the constant pressure portion is determined by analyzing the gasdynamics of the self-similar flow behind a steadily moving detonation wave within the tube. The gas expansion process is modeled using dimensional analysis and empirical observations. The model predictions are validated against direct experimental measurements in terms of impulse per unit volume, specific impulse, and thrust. Comparisons are given with estimates of the specific impulse based on numerical simulations. Impulse per unit volume and specific impulse calculations are carried out for a wide range of fuel–oxygen–nitrogen mixtures (including aviation fuels) of varying initial pressure, equivalence ratio, and nitrogen dilution. The effect of the initial temperature is also investigated. The trends observed are explained using a simple scaling analysis showing the dependency of the impulse on initial conditions and energy release in the mixture