A preliminary design for a satellite power system

Outlined here is a preliminary design for a Solar Power Satellite (SPS) system. The SPS will provide a clean, reliable source of energy for mass consumption. The system will use satellites in geostationary orbits around the Earth to capture the sun's energy. The intercepted sunlight will be converted to laser beam energy which can be transmitted to the Earth's surface. Ground systems on the Earth will convert the transmissions from space into electric power. The preliminary design for the SPS consists of one satellite in orbit around the Earth transmitting to one ground station. The SPs technology uses multi-layer solar cell technology arranged on a 20 sq km planar array to intercept sunlight and convert it to an electric voltage. Power conditioning devices then send the electricity to a laser, which transmits the power to the surface of the Earth. A ground station will convert the beam into electricity. Construction will take place in low Earth orbit and array sections, 20 in total, will be sailed on the solar wind out to the GEO location in 150 days. These individual transportation sections are referred to as solar sailing panels (SSAPs). The primary truss elements used to support the arrays are composed on composite tubular members in a pentahedral arrangement. Smart segments consisting of passive and active damping devices will increase the control of dynamic SPS modes

THE RELATIONSHIP AMONG REPEATED SPRINT AND CHANGE OF DIRECTION ABILITIES IN FOOTBALL PLAYERS WITH CEREBRAL PALSY

This study aimed to describe and determine relationships between repeated sprint and change of direction abilities in football players with cerebral palsy according to four sport classes (FT5 to FT8). Seventeen male football players with cerebral palsy took part in this study (23.0±4.7 years, 65.9±9.5 kg, 168.8±5.9 cm). The repeated sprint ability (6×40-m sprints with a 20-second recovery) was evaluated to determine the best sprint time, mean sprint time, and percentage of sprint decrement. The difference in lactate concentration was determined using blood samples taken three minutes before and after testing. The Illinois Agility Test (IAT) was also used to assess players’ change of direction ability. The FT8 players had better performance (p&lt;.01) in the best sprint time, mean sprint time and in the IAT scores compared to the players of the sport classes FT5/6. Players of the sport class FT7 also reached higher performance in the IAT compared to the players of the sport classes FT5/6 (p&lt;.05). A significant correlation was found between the best sprint time and mean sprint time (r=.94, p&lt;.01), the best sprint time and the IAT (r=.62, p&lt;.01), and between the best sprint time and the difference in lactate concentration (r=-.51, p&lt;.05). The relationships between repeated sprint and change of direction abilities demonstrate the performance profile of para-footballers with cerebral palsy in those variables according to their sport classes, exhibiting lower performance than the values reported for regular football players.Keywords: physical performance, para-sport, brain impairment, Paralympic sport</p

Plant phenolics and absorption features in vegetation reflectance spectra near 1.66μm

AbstractPast laboratory and field studies have quantified phenolic substances in vegetative matter from reflectance measurements for understanding plant response to herbivores and insect predation. Past remote sensing studies on phenolics have evaluated crop quality and vegetation patterns caused by bedrock geology and associated variations in soil geochemistry. We examined spectra of pure phenolic compounds, common plant biochemical constituents, dry leaves, fresh leaves, and plant canopies for direct evidence of absorption features attributable to plant phenolics. Using spectral feature analysis with continuum removal, we observed that a narrow feature at 1.66μm is persistent in spectra of manzanita, sumac, red maple, sugar maple, tea, and other species. This feature was consistent with absorption caused by aromatic CH bonds in the chemical structure of phenolic compounds and non-hydroxylated aromatics. Because of overlapping absorption by water, the feature was weaker in fresh leaf and canopy spectra compared to dry leaf measurements. Simple linear regressions of feature depth and feature area with polyphenol concentration in tea resulted in high correlations and low errors (% phenol by dry weight) at the dry leaf (r2=0.95, RMSE=1.0%, n=56), fresh leaf (r2=0.79, RMSE=2.1%, n=56), and canopy (r2=0.78, RMSE=1.0%, n=13) levels of measurement. Spectra of leaves, needles, and canopies of big sagebrush and evergreens exhibited a weak absorption feature centered near 1.63μm, short ward of the phenolic compounds, possibly consistent with terpenes. This study demonstrates that subtle variation in vegetation spectra in the shortwave infrared can directly indicate biochemical constituents and be used to quantify them. Phenolics are of lesser abundance compared to the major plant constituents but, nonetheless, have important plant functions and ecological significance. Additional research is needed to advance our understanding of the spectral influences of plant phenolics and terpenes relative to dominant leaf biochemistry (water, chlorophyll, protein/nitrogen, cellulose, and lignin)

La historia se escribe con los pies. Una conversación con Nora Strejilevich en Valparaíso

La historia se escribe con los pies. Una conversación con Nora Strejilevich en Valparaíso (25 de septiembre de 2023) &nbsp; por María Eugenia Kokal

Metochi of St. Savva's Monastery in the city of Bethlehem

Σημείωση: η ηλεκτρονική έκδοση για λόγους διαχείρισης μεγέθους έχει διασπαστεί σε πάνω από ένα τόμους/αρχεία. Παρακαλούμε, κατεβάστε πρώτα όλα τα αρχεία, διατηρώντας τα στην ίδια τοποθεσία, και αποσυμπιέστε μόνο το αρχείο με την κατάληξη .zi

Spectral Analysis of Absorption Features for Mapping Vegetation Cover and Microbial Communities in Yellowstone National Park Using AVIRIS Data

This report summarizes the application of imaging spectroscopy to the study of biotic components of Yellowstone National Park ecosystems. Maps of vegetation cover and hot-spring microorganisms were generated using spectral-feature analysis of data from the airborne visible and infrared imaging spectrometer (AVIRIS). AVIRIS data were calibrated to surface reflectance using a radiative-transfer model and a ground-calibration target. A spectral library of canopy-reflectance signatures was created by averaging pixels of reflectance data over known occurrences of 27 vegetation cover types in Yellowstone. Distributions of these vegetation types were determined by comparing absorption features of the vegetation in the spectral library with every pixel of the AVIRIS data using continuum removal and spectral analysis in the U.S. Geological Survey’s Tetracorder expert system. Analysis of the chlorophyll- and leaf-water-absorption features (centered near 0.68, 0.98, and 1.20 μm, respectively) allowed accurate identification of vegetation cover types. Conifer cover types of lodgepole pine, whitebark pine, Douglas fir, and a mixed Engelmann spruce/subalpine fir class were spectrally identified and their distributions were mapped in AVIRIS images. Field-reflectance measurements revealed a distinct spectral signature of hot-spring microorganisms. These field measurements were added to the vegetation spectral library, and maps showing the distributions of microbial mats in the geyser basins of Yellowstone were produced

User Experience for Model-Driven Engineering : Challenges and Future Directions

Since its infancy, Model Driven Engineering (MDE) research has primarily focused on technical issues. Although it is becoming increasingly common for MDE research papers to evaluate their theoretical and practical solutions, extensive usability studies are still uncommon. We observe a scarcity of User eXperience (UX)-related research in the MDE community, and posit that many existing tools and languages have room for improvement with respect to UX [26], [44], [37], where UX is a key focus area in the software development industry. We consider this gap a fundamental problem that needs to be addressed by the community if MDE is to gain widespread use. In this vision paper, we explore how and where UX fits into MDE by considering motivating use cases that revolve around different dimensions of integration: model integration, tool integration, and integration between process and tool support. Based on the literature and our collective experience in research and industrial collaborations, we propose future directions for addressing these challenges

Crack paths under mixed mode loading

Long fatigue cracks that initially experience mixed mode displacements usually change direction in response to cyclic elastic stresses. Eventually the cracks tend to orient themselves into a pure mode I condition, but the path that they take can be complex and chaotic. In this paper, we report on recent developments in techniques for tracking the crack path as it grows and evaluating the strength of the mixed mode crack tip stress field