Continued Monitoring of Landsat Reflective Band Calibration Using Pseudo-Invariant Calibration Sites

Though both of the current Landsat instruments, Landsat-7 Enhanced Thematic Mapper+ (ETM+) and Landsat-5 Thematic Mapper (TM), include on-board calibration systems, since 2001, pseudo-invariant calibration sites (PICS) have been added to the suite of metrics to assess the instruments calibration. These sites do not provide absolute calibration data since there are no ground measurements of the sites, but in monitoring these PICS over time, the relative calibration can be tracked. The sites used by the Landsat instruments are primarily in the Saharan Desert. To date, the trending from the PICS sites has confirmed that most of the degradation seen in the ETM+ on-board calibration systems is likely not degradation of the instrument, but rather degradation of the calibration systems themselves. However, the PICS data show statistically significant degradation (at 2-sigma) in all the reflective spectral bands of up to -0.22%/year since July 2003. For the TM, the PICS were instrumental in updating the calibration in 2007 and now suggest two bands may require another update. The data show a statistically significant degradation (at 2-sigma) in Bands 1 and 3 of -0.27 and -0.15%/year, respectively, since March 1999. The data filtering and processing methods are currently being reviewed but these PICS results may lead to an update in the reflective band calibration of both Landsat-7 and Landsat-5

Kinetochore-driven formation of kinetochore fibers contributes to spindle assembly during animal mitosis

It is now clear that a centrosome-independent pathway for mitotic spindle assembly exists even in cells that normally possess centrosomes. The question remains, however, whether this pathway only activates when centrosome activity is compromised, or whether it contributes to spindle morphogenesis during a normal mitosis. Here, we show that many of the kinetochore fibers (K-fibers) in centrosomal Drosophila S2 cells are formed by the kinetochores. Initially, kinetochore-formed K-fibers are not oriented toward a spindle pole but, as they grow, their minus ends are captured by astral microtubules (MTs) and transported poleward through a dynein-dependent mechanism. This poleward transport results in chromosome bi-orientation and congression. Furthermore, when individual K-fibers are severed by laser microsurgery, they regrow from the kinetochore outward via MT plus-end polymerization at the kinetochore. Thus, even in the presence of centrosomes, the formation of some K-fibers is initiated by the kinetochores. However, centrosomes facilitate the proper orientation of K-fibers toward spindle poles by integrating them into a common spindle

Summary of Current Radiometric Calibration Coefficients for Landsat MSS, TM, ETM+, and EO-1 ALI Sensors

This paper provides a summary of the current equations and rescaling factors for converting calibrated Digital Numbers (DNs) to absolute units of at-sensor spectral radiance, Top-Of- Atmosphere (TOA) reflectance, and at-sensor brightness temperature. It tabulates the necessary constants for the Multispectral Scanner (MSS), Thematic Mapper (TM), Enhanced Thematic Mapper Plus (ETM+), and Advanced Land Imager (ALI) sensors. These conversions provide a basis for standardized comparison of data in a single scene or between images acquired on different dates or by different sensors. This paper forms a needed guide for Landsat data users who now have access to the entire Landsat archive at no cost

Process control in next-generation sewing machines : a project overview

The sewing machine created in the XIX century has roughly remained unchanged in its basic technologies. Although a great range of mechanical and electronic technologies has boosted its development enormously, the process of sewing itself, however, although perfected in many aspects, has remained uncontrolled.Many of the phenomena occurring at high-speed sewing (up to 10000 stitches per minute) are still not properly understood. This project is creating a deeper insight into the sewing process, identifying and describing the variables that can be monitored and/or controlled in a way that ensures a better control of this production process. Some monitoring and control algorithms are already under test. Concurrently the project develops software support tools to allow the up-front engineering of the process, resulting in control parameters to be downloaded to the machine controllers. The software would also serve as a support tool for the textile manufacturer, to tune and improve materials’ properties and define the relationship between materials and optimum sewing conditions.Fundação para a Ciência e a Tecnologia (FCT) – Project funding POSI/SRI/38944/2001

Deposition of conductive materials on textile and polymeric flexible substrates

This paper describes the study, analysis and selection of textile and similar materials to be used as flexible substrates for thin conductive film deposition, in the context of integrating electronics into textiles. Kapton® polyimide was chosen as reference substrate material, was characterized regarding mechanical and electrical properties and was used as a basis for a comparison with several textile substrates. Samples were fabricated using physical vapour deposition (thermal evaporation) to deposit a thin layer of aluminium on top of Kapton and textile substrates. The measurement of electrical resistance of the thin aluminum films was carried out using the Kelvin method. To characterize the mechanical behaviour of the substrate and aluminum film, several mechanical tests were performed and results were compared between Kapton and these textile materials. The chemical composition of the textile substrates and aluminum films as well as the continuity of the films was characterized. This selection process identified the material that was closer to the behaviour of polyimide, a flexible, but non-elastic woven textile coated on both sides with PVC.FEDER funds in COMPETE program and by FCT, in the project FCOMP-01-0124-FEDER-02267

Simulation of a downdraft gasifier for production of syngas from different biomass feedstocks

In the evaluation of gasification processes, estimating the composition of the fuel gas for different conditions is fundamental to identify the best operating conditions. In this way, modeling and simulation of gasification provide an analysis of the process performance, allowing for resource and time savings in pilot-scale process operation, as it predicts the behavior and analyzes the effects of different variables on the process. Thus, the focus of this work was the modeling and simulation of biomass gasification processes using the UniSim Design chemical process software, in order to satisfactorily reproduce the operation behavior of a downdraft gasifier. The study was performed for two residual biomasses (forest and agricultural) in order to predict the produced syngas composition. The reactors simulated gasification by minimizing the free energy of Gibbs. The main operating parameters considered were the equivalence ratio (ER), steam to biomass ratio (SBR), and gasification temperature (independent variables). In the simulations, a sensitivity analysis was carried out, where the effects of these parameters on the composition of syngas, flow of syngas, and heating value (dependent variables) were studied, in order to maximize these three variables in the process with the choice of the best parameters of operation. The model is able to predict the performance of the gasifier and it is qualified to analyze the behavior of the independent parameters in the gasification results. With a temperature between 850 and 950 C, SBR up to 0.2, and ER between 0.3 and 0.5, the best operating conditions are obtained for maximizing the composition of the syngas in CO and H2.info:eu-repo/semantics/publishedVersio