Thermal insulating conformal blanket

The conformal thermal insulating blanket may have generally rigid batting material covered by an outer insulating layer formed of a high temperature resistant woven ceramic material and an inner insulating layer formed of a woven ceramic fiber material. The batting and insulating layers may be fastened together by sewing or stitching using an outer mold layer thread fabricated of a high temperature resistant material and an inner mold layer thread of a ceramic fiber material. The batting may be formed to a composite structure that may have a firmness factor sufficient to inhibit a pillowing effect after the stitching to not more than 0.03 inch. The outer insulating layer and an upper portion of the batting adjacent the outer insulating layer may be impregnated with a ceramic coating material

Secondary forest succession in the Mata Atlantica, Brazil: floristic and phytosociological trends.

This study aimed at understanding the dynamics of ecological processes and the use of secondary forests in Santa Catarina state (Brazil). The data base for these studies was formed through forest inventories carried out in the three forest types of the state. The results of this study demonstrate that the patterns of diversity are very similar among the three forest types; however, the species compositions among the types are quite different. A total of 343 woody species belonging to 73 families were found in the 24,000 m2 sampling area, revealing the potential role of secondary forest in the conservation of biodiversity at the landscape scale. As expected, a small set of pioneer species dominates young secondary forests with shade-tolerant species becoming structurally important after 30 years. The patterns of forest structure and species diversity observed in study largely conform to the postagricultural secondary succession observed for many tropical forests.Article ID 759893

Single track orbit determination analysis for low Earth orbit with approximated J2 dynamics

In the domain of Space Situational Awareness (SSA), the challenges pertaining to orbit determination and catalog correlation are notably pronounced, partly attributable to the escalating presence of non-cooperative satellites engaging in unspecified maneuvers at irregular intervals. This study introduces an initial orbit determination methodology reliant upon data obtained from a single surveillance radar, such as the Spanish Space Surveillance and Tracking Surveillance Radar (S3TSR). The need for fast algorithms within an operational context is considered here as the main design driver. The result is a least-squares fitting procedure that incorporates an analytically formulated approximation of the dynamics under the J2 perturbation, valid for short-term propagation. The algorithm makes use of all available observables, including range-rate, which makes it distinct from other similar methods. The method is compared in a battery of synthetic tests against a classical range and angles fitting method (GTDS) to study the effect of the track length and density of measurements on the full state estimation. The presented methodology is quite versatile, and it is leveraged to improve the estimation quality by adding information of the object's orbital plane obtained from predictions. The resulting method has been named OPOD

Application of attributables to the correlation of surveillance radar measurements.

Space surveillance by radar is especially used for the low Earth orbit to maintain a database, also calledcatalogue, of objects on orbit. Among others, surveillance radars which are constantly scanning a region ofinterest in the sky are used for this purpose. The detections from such a radar which cannot be assigned toan already known catalogue object might not contain enough information to obtain a reliable initial orbitfor a new catalogue entry from a single measured pass, also called tracklet. Instead, two tracklets can becombined to improve the quality of the initial orbit which leads to the correlation problem. This means thatit has to be tested whether two tracklets belong to the same object and an initial orbit has to be derivedby combining the tracklets. A common approach to condense the information in the tracklet is fitting themwith so-called attributables. Because radar observations include different types of observables, the fitting ofthese attributables has to be considered as an important part of the entire correlation process. This paperanalyses the effect of the attributable fitting considering the achieved accuracy and influence on the trackletcorrelation. A new singularity-free coordinate system is introduced, which improves the results of the fittingand correlation. Finally, a test on a simulated survey scenario introduces two additional filters to remove falsepositive correlations. It is shown that the attributable-based approach can be applied successfully to trackletsof up to three minutes length with different detection frequencie

Strong floristic distinctiveness across Neotropical successional forests

Forests that regrow naturally on abandoned fields are important for restoring biodiversity and ecosystem services, but can they also preserve the distinct regional tree floras? Using the floristic composition of 1215 early successional forests (≤20 years) in 75 human-modified landscapes across the Neotropic realm, we identified 14 distinct floristic groups, with a between-group dissimilarity of 0.97. Floristic groups were associated with location, bioregions, soil pH, temperature seasonality, and water availability. Hence, there is large continental-scale variation in the species composition of early successional forests, which is mainly associated with biogeographic and environmental factors but not with human disturbance indicators. This floristic distinctiveness is partially driven by regionally restricted species belonging to widespread genera. Early secondary forests contribute therefore to restoring and conserving the distinctiveness of bioregions across the Neotropical realm, and forest restoration initiatives should use local species to assure that these distinct floras are maintained