High resolution time profile of decimetric type-III bursts

Type-III bursts are signatures of the electron beams accelerated during the solar flares, their observation and investigation provide information of the acceleration processes, the characteristics of the exciting agent and the acceleration site. The Brazilian Solar Spectroscope (BSS), in operation at INPE, Brazil, have recorded type-III radio bursts in decimetric range (2050–2250 MHz) with high time resolution of 20 ms. Decimetric reverse drift bursts are possibly generated in a dense loop by electron beams travelling towards the photosphere. Hence their time profiles should carry signatures of the density inhomogenities in the loop. Here the temporal and spectral characteristics of decimetric type-III bursts are presented.     

Atmospheric dynamics in the "Laboratory Biosphere" with wheat and sweet potato crops.

Laboratory Biosphere is a 40-m3 closed life system equipped with 12,000 W of high pressure sodium lamps over planting beds with 5.37 m2 of soil. Atmospheric composition changes due to photosynthetic fixation of carbon dioxide and corresponding production of oxygen or the reverse, respiration, are observed in short timeframes, e.g., hourly. To focus on inherent characteristics of the crop as distinct from its area or the volume of the chamber, we report fixation and respiration rates in mmol h-1 m-2 of planted area. An 85-day crop of USU Apogee wheat under a 16-h lighted/8-h dark regime peaked in fixation rate at about 100 mmol h-1 m-2 approximately 24 days after planting. Light intensity was about 840 micromoles m-2 s-1. Dark respiration peaked at about 31 mmol h-1 m-2 at the same time. Thereafter, both fixation and respiration declined toward zero as harvest time approached. A residual soil respiration rate of about 1.9 mmol h-1 m-2 was observed in the dark closed chamber for 100 days after the harvest. A 126-day crop of Tuskegee TU-82-155 sweet potato behaved quite differently. Under a 680 micromoles m-2 s-1, 18-h lighted/6-h dark regime, fixation during lighted hours rose to a plateau ranging from about 27 to 48 mmol h-1 m-2 after 42 days and dark respiration settled into a range of 12-23 mmol h-1 m-2. These rates continued unabated until the harvest at 126 days, suggesting that tuber biomass production might have continued at about the same rate for some time beyond the harvest time that was exercised in this experiment. In both experiments CO2 levels were allowed to range widely from a few hundred to about 3000 ppm, which permitted observation of fixation rates both at varying CO2 concentrations and at each number of days after planting. This enables plotting the fixation rate as a function of both variables. Understanding the atmospheric dynamics of individual crops will be essential for design and atmospheric management of more complex CELSS which integrate the simultaneous growth of several crops as in a sustainable remote life support system.     

3D Coronal structures and their evolutions measured by Stereoscopy,consequences for Space Weather and the STEREO mission

We are discussing methods of stereoscopic 3D reconstruction of coronal loops structures. In our most sophisticated method we fit loops observed with SOHO/EIT to a set of shape parameters including the internal twist of the loops field lines. We define this twist as the number of turns of the field line around a torus axis between the footpoints of the loops. Twist numbers of the order 0–2 are observed. We observe the emergence of an Active Region with twisted loops which detwist as they expand. The same correlation between detwisting and expansion is observed with filaments in relation to CME formations. On longer time scale, loops seem to accumulate twist, perhaps due to differential rotation. Rapid losses of twist temporarily correlate with flares. From our analysis, we expect that the internal twist of coronal structures will play an important role for the space weather forecast. This revised version was published online in August 2006 with corrections to the Cover Date.     

Novel sensor technology for monitoring and control of critical plant nutrient parameters.

A novel dielectric sensor technology has been developed for monitoring and control of plant nutrient delivery systems as part of NASA's Controlled Ecological Life Support System (CELSS) program. A unique measurement phenomenon was discovered in which the electrostatic field is shunted to a third terminal of the sensor, resulting in a much greater sensitivity to changes in the complex dielectric properties of the nutrient solution. Based on this phenomenon, a small, flexible, thin-film shunting dielectric sensor (SDS) was designed to provide low-frequency, non-invasive measurement of both the thickness and nutrient concentration of the layer of solution on a plant growth surface. Test results indicate a sensitivity of +/- 0.05mm in layer thickness while characterization of the ability to measure nutrient concentration continues. The development plan for this sensor is presented and other applications are discussed.     

Avionics cost of ownership

The cost of ownership of avionics includes not only the development and acquisition cost, but also the yearly operating and support (O and S) (maintenance) cost of hardware, software, and support equipment. This paper presents an avionics cost of ownership methodology developed for USAF, its data sources, and business metrics computed for USAF decision makers as we move toward operating avionics as a business. The business model is used to determine which existing avionics are candidates for replacement with new technology and to prioritize the replacements. These avionics are often used on multiple aircraft types which necessitates analysis of the causes of the high cost of ownership on each type. Databases are used to document the processing functions, data flow, and constraints of the item being analyzed. These constraints include physical, environmental, electrical, and data interfaces. Databases containing alternatives are evaluated against standard mission scenarios for aircraft utilizing these high cost avionics to determine their impact on performance, O and S costs, and mission effectiveness. The results of the foregoing analyses steps are then used in life cycle cost analyses which consider different retrofit scenarios for each alternative for each aircraft type against the avionics being analyzed for replacement. The alternatives are prioritized and a risk analysis performed considering technical, schedule, and cost growth risks. The avionics cost of ownership methodology described in this paper processes data from USAF maintenance organizations. This has revealed the very large expenditures being made to support highly unreliable avionics. These methods can be applied to all military and commercial aircraft systems to determine not only the cost of ownership of existing systems, but also the cost of ownership of new systems when they are retrofit     

GNSS receiver for GLONASS signal reception

This paper deals with the latest version of Experimental GNSS receiver built at the Czech Technical University and describes integration of GLONASS signal processing to the receiver. The new FPGA platform Virtex-D Pro by Xilinx is used and enables integration of whole digital signal processing of GNSS receiver into the single chip. The RE unit of the receiver is capable of processing all GLONASS frequency of the Li and L2 bands in two independent RE channels; each channel can process one band. The frequency selection of the appropriate satellite is accomplished in a digital correlator. The development flow of the GLONASS correlator is discussed herein. The complexity of the GLONASS correlator with complexity of GPS correlator is compared. The developed GLONASS correlator was tested in Simuelink tool during development. The next test was carried out using GLONASS simulator and real GLONASS satellite signal.     

Radiation biodosimetry: applications for spaceflight.

The multiparametric dosimetry system that we are developing for medical radiological defense applications could be adapted for spaceflight environments. The system complements the internationally accepted personnel dosimeters and cytogenetic analysis of chromosome aberrations, considered the best means of documenting radiation doses for health records. Our system consists of a portable hematology analyzer, molecular biodosimetry using nucleic acid and antigen-based diagnostic equipment, and a dose assessment management software application. A dry-capillary tube reagent-based centrifuge blood cell counter (QBC Autoread Plus, Becton [correction of Beckon] Dickinson Bioscience) measures peripheral blood lymphocytes and monocytes, which could determine radiation dose based on the kinetics of blood cell depletion. Molecular biomarkers for ionizing radiation exposure (gene expression changes, blood proteins) can be measured in real time using such diagnostic detection technologies as miniaturized nucleic acid sequences and antigen-based biosensors, but they require validation of dose-dependent targets and development of optimized protocols and analysis systems. The Biodosimetry Assessment Tool, a software application, calculates radiation dose based on a patient's physical signs and symptoms and blood cell count analysis. It also annotates location of personnel dosimeters, displays a summary of a patient's dosimetric information to healthcare professionals, and archives the data for further use. These radiation assessment diagnostic technologies can have dual-use applications supporting general medical-related care.     

Development of a Digital Array Radar (DAR)

Twenty-first century littoral and open-sea missions present US Navy (USN) shipboard-radar systems with the challenge of detecting small targets in severe clutter and against multiple sources of interference. In Fiscal Year 2000 (FY00), the Office of Naval Research (ONR) sponsored a program to develop an active array radar that includes a digital beamforming (DBF) architecture. The DBF radar system has the potential for improved time-energy management, improved signal-to-clutter (S/C) ratios, improved reliability and reduced life-cycle costs. This paper summarizes the latest developments of the program during FY00     

Asynchronous router specification

We describe the application of three formal design tools to a case study in the design of a distributed system. The case study in question involves the specification of an asynchronous message router; the three design tools are process algebra (specifically Milner's Calculus of Communicating Systems CCS), the modal μ-calculus and the Edinburgh Concurrency Workbench (CWB). We demonstrate how an informally-presented specification can be formalised within the language of the modal μ-calculus, allowing for a rigorous mathematical analysis of the correctness of our proposed implementation. For modest-sized versions of the router, this correctness proof has been carried out using the CWB