Solar Isotopic Composition as Determined Using Solar Energetic Particles

Solar energetic particles (SEPs) provide a sample of the Sun from which solar composition may be determined. Using high-resolution measurements from the Solar Isotope Spectrometer (SIS) onboard NASA’s Advanced Composition Explorer (ACE) spacecraft, we have studied the isotopic composition of SEPs at energies ≥20 MeV/nucleon in large SEP events. We present SEP isotope measurements of C, O, Ne, Mg, Si, S, Ar, Ca, Fe, and Ni made in 49 large events from late 1997 to the present. The isotopic composition is highly variable from one SEP event to another due to variations in seed particle composition or due to mass fractionation that occurs during the acceleration and/or transport of these particles. We show that various isotopic and elemental enhancements are correlated with each other, discuss the empirical corrections used to account for the compositional variability, and obtain estimated solar isotopic abundances. We compare the solar values and their uncertainties inferred from SEPs with solar wind and other solar system abundances and find generally good agreement.     

In-orbit demonstration of rendezvous laser radar for unmanned autonomous rendezvous docking

The National Space Development Agency of Japan (NASDA) performed unmanned autonomous rendezvous docking (RVD) experiments using the Engineering Test Satellite VII (ETS-VII) in 1998 and 1999. In these experiments, a rendezvous laser radar (RVR) was used as the primary navigation sensor during the final approach phase (relative distances from 500 m to 2 m). The RVR functioned properly, and its characteristics, which are measurement accuracy, optical propagation, and acquisition/tracking, satisfied the requirements. The experimental results show that RVR is effective for autonomous rendezvous docking.     

Multi-Criteria Decision Analysis integrated with GIS and remote sensing for astronomical observatory site selection in Antalya province,Turkey

Astronomical observatory site selection is a complex problem that involves evaluation of multiple factors from different sources. The aim of this study is to select the best possible candidates for astronomical observations sites using Multi-Criteria Decision Analysis integrated with Geographical Information Systems and remote sensing technologies. The study was implemented in the Antalya province of Turkey, which is convenient for astronomical site observatory facilities with its appropriate climate properties and weather conditions. Eleven factors (cloud cover, precipitable water, earthquake zones, geology, landslide inventory, active fault lines, Digital Elevation Model, city lights, mining activities, settlement areas, roads) were determined, splitting into three categories; meteorological, geographical and anthropogenic criteria. These factors were evaluated using Analytical Hierarchy Process method and the weights of criteria layers were determined. As a result, the most suitable areas were located extensively in western and eastern part of Antalya. This study offers a robust, accurate, cost and time effective procedure for preliminary site selection for astronomical observatory. However, for a final decision of the best location of astronomical observatory, site testing measurements and atmospheric seeing observations will be further required in these preliminary areas.     

Zinc-air batteries for forward field charging

In order to realize the operational and service cost savings through the use of rechargeable batteries, the dismounted soldier is burdened with the weight, volume and/or charging logistics of the batteries. By providing the soldier with a high energy density source and a lightweight compact battery charger, the burden imposed by rechargeable batteries in the forward field can be minimized. Zinc-air batteries have the potential for meeting the energy demands of forward battlefield charging. They are attitude insensitive, have a high specific energy and are inherently inexpensive, lightweight and safe     

Radiative and dynamical impacts of Arctic and Antarctic ozone holes: General circulation model experiments

Radiative and dynamical impacts of Arctic and Antarctic ozone holes on the general circulation are investigated with the aid of a general circulation model developed at Kyushu University. The model includes a simplified ozone photochemistry interactively coupled with radiation and dynamics. Resultant temperature structure consisting of a cooling in the polar lower stratosphere and a warming in the polar upper stratosphere brings about the intensification of the polar night jet. The cooling is caused by the decrease of solar ultraviolet heating due to the ozone depletion, while the warming is caused by adiabatic heating due to the enhancement of downward motion.     

Performance analysis of linearly combined order statistic CFARdetectors

Linearly combined order statistic (LCOS) constant false-alarm rate (CFAR) detectors are examined for efficient and robust threshold estimation applied to exponentially distributed background observations for improved detection. Two optimization philosophies have been employed to determine the weighting coefficients of the order statistics. The first method optimizes the coefficients to obtain efficient estimates of clutter referred to the censored maximum likelihood (CML) and best linear unbiased (BLU) CFAR detectors. The second optimization involves maximizing the probability of detection under Swerling II targets and is referred to as the most powerful linear (MPL) CFAR detector. The BLU-CFAR detector assumes no knowledge of the target distribution in contrast to the MPL-CFAR detector which requires partial knowledge of the target distribution. The design of these CFAR detectors and the probability of detection performance are mathematically analyzed for background observations having homogeneous and heterogeneous distributions wherein the trade-offs between robustness and detection performance are illustrated