62 research outputs found
A COMPUTER PROGRAM FOR SIMULATING SOME SIGNAL-TO-NOISE ENHANCEMENT METHODS USED IN HIGH PERFORMANCE INSTRUMENTS
A computer program for a personal computer was written to test seven noise filtering
methods with simulated signals buried in noise for education. The methods tested were as
follows: filtering by an RC network, accumulation, sampling with integration, smoothing by
Savitzky-Golay filter, combination of accumulation and Savitzky-Golay smoothing, combination
of integral sampling and Savitzky-Golay smoothing and filtering by Fourier
transformation. The two combined methods have yielded the best results
A novel virtual flow diverter implantation method with realistic deployment mechanics and validated force response
Hydrodynamic Resistance of Intracranial Flow-Diverter Stents:Measurement Description and Data Evaluation
Hydrodynamic Resistance of Intracranial Flow-Diverter Stents:Measurement Description and Data Evaluation
Preferential CO oxidation in hydrogen (PROX) on ceria-supported catalysts PART II. Oxidation states and surface species on Pd/CeO2 under reaction conditions, suggested reaction mechanism
The aim of the PROX reaction is to reduce the CO content of hydrogen feed to proton-exchange membrane fuel cells (PEMFCs) by selective oxidation of CO in the presence of excess hydrogen. Both Pt and Pd on ceria are active in CO oxidation (without hydrogen), whereas Pd is poorly active in the presence of hydrogen. In this paper we explore the reasons for such behavior, using the same techniques for Pd/CeO2 as used for Pt/CeO2 in Part I: catalytic tests, in situ DRIFTS, high-pressure XPS, HRTEM, and TDS. We also examine the reaction mechanism of CO oxidation (without hydrogen), which does not occur via exactly the same mechanism on Pt and Pd/CeO2 catalysts. In the presence of hydrogen (PROX) at low temperature (T = 350–380 K), the formation of Pd β-hydride was confirmed by high-pressure in situ XPS. Its formation greatly suppressed the possibility of CO oxidation, because oxygen both from gas-phase and support sites reacted rapidly with hydride H to form water, which readily desorbed from Pd. Nevertheless, CO adsorption was not hampered here. These entities transformed mainly to surface formate and formyl (–CHO) species instead of oxidation as observed by DRIFTS. The participation of a low-temperature water–gas shift type reaction proposed for the platinum system (see Part I) was hindered. Increasing temperature led to decomposition of the hydride phase and a parallel increase in the selectivity toward CO oxidation. This still remained lower on Pd/CeO2 than on Pt/CeO2, however
Imaging of hydrothermal altered zones in Wadi Al-Bana, in southern Yemen, using remote sensing techniques and very low frequency–electromagnetic data
© 2019, Saudi Society for Geosciences. Economic mineralization and hydrothermally altered zones are areas of great economic interests. This study focusses on hydrothermal altered zones of high mineralization potentials in Wadi Al-Bana, in southern Yemen. An azimuthal very low frequency–electromagnetic (AVLF-EM) data acquisition was conducted in search for mineralization in the study area. The study integrated observations from geophysical field data with others extracted from object-oriented principal component analysis (PCA) to better map and understand mineralization in the investigated area. This technique was applied to two data sets, ASTER and Landsat 8 Operational Land Imager (OLI) imagery. The results of PCA revealed high accuracy in detecting alteration minerals and for mapping zones of high concentration of these minerals. The PCA-based distribution of selected alteration zones correlated spatially with high conductivity anomalies in the subsurface that were detected by VLF measurements. Finally, a GIS model was built and successfully utilized to categorize the resulted altered zones, into three levels. [Figure not available: see fulltext.]
Development of Anhydrous Ethanol Purification: Reduction of Acetal Content and Vapor–Liquid Equilibrium Study of the Ethanol–Acetal Binary System
Obtenção do saldo de radiação em áreas de pastagem e floresta na amazônia (estação seca) através do sensor MODIS
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