Dynamical Processing of Geophysical Signatures based on SPOT-5 Remote Sensing Imagery

An intelligent post-processing computational paradigm based on the use of dynamical filtering techniques modified to enhance the quality of reconstruction of geophysical signatures based on Spot-5 imagery is proposed. As a matter of particular study, a robust algorithm is reported for the analysis of the dynamic behavior of geophysical indexes extracted from the real-world remotely sensed scenes. The simulation results verify the efficiency of the approach as required for decision support in resources management

CO and C 3

ZnSb2O6 has been synthesized by a microwave-assisted solution method in order to test its possible application as a gas sensor. Zinc nitrate, antimony trichloride, and ethylenediamine were used as precursors and deionized water as solvent. Microwave radiation, with a power of ~350 W, was applied for solvent evaporation. The thermal decomposition of the precursors leads to the formation of ZnSb2O6 at 600°C. This oxide crystallized in a tetragonal structure with cell parameters a=4.66 Å, c=9.26 Å and space group P42/mnm. Microwires and microrods formed by nanocrystals were observed by means of scanning and transmission electron microscopies (SEM and TEM, resp.). Pellets of the oxide were tested as gas sensors in flowing atmospheres of carbon monoxide (CO) and propane (C3H8). Sensitivity increased with the gas concentration (0–300 ppm) and working temperatures (ambient, 150 and 250°C) increase. The results indicate high sensitivity of ZnSb2O6 in both gases at different concentrations and operating temperatures

Dynamical processing of geophysical signatures based on spot-5 remote sensing imagery

Experimental work on the synthesis of the CoSb2O6 oxide and its CO2 sensing properties is presented here. The oxide was synthesized by a microwave-assisted colloidal method in presence of ethylenediamine after calcination at 600 °C. This CoSb2O6 oxide crystallized in a tetragonal structure with cell parameters ?= 4.6495 and c= 9.2763 Å, and space group P42/mnm. To prove its physical, chemical and sensing properties, the oxide was subjected to a series of tests: Raman spectroscopy, Scanning Electron Microscopy (SEM) and impedance (Z) measurements. Microstructures, like columns, bars and hollow hemispheres, were observed. For the CO2 sensing test, a thick film of CoSb2O6 was used, measuring the impedance variations on the presence of air/CO2 flows (0.100 sccm/0.100 sccm) using AC (alternating current) signals in the frequency-range 0.1-100 kHz and low relative temperatures (250 and 300 °C). The CO2 sensing results were quite good. " 2014 by the authors; licensee MDPI, Basel, Switzerland.",,,,,,"10.3390/s140915802",,,"http://hdl.handle.net/20.500.12104/40814","http://www.scopus.com/inward/record.url?eid=2-s2.0-84906871340&partnerID=40&md5=0ef48f570dd2426756a43bbd0f6ef83

Dynamic response of CoSb2O6 trirutile-type oxides in a CO2 atmosphere at low-temperatures

Experimental work on the synthesis of the CoSb2O6 oxide and its CO2 sensing properties is presented here. The oxide was synthesized by a microwave-assisted colloidal method in presence of ethylenediamine after calcination at 600 °C. This CoSb2O6 oxide crystallized in a tetragonal structure with cell parameters α= 4.6495 and c= 9.2763 Å, and space group P42/mnm. To prove its physical, chemical and sensing properties, the oxide was subjected to a series of tests: Raman spectroscopy, Scanning Electron Microscopy (SEM) and impedance (Z) measurements. Microstructures, like columns, bars and hollow hemispheres, were observed. For the CO2 sensing test, a thick film of CoSb2O6 was used, measuring the impedance variations on the presence of air/CO2 flows (0.100 sccm/0.100 sccm) using AC (alternating current) signals in the frequency-range 0.1-100 kHz and low relative temperatures (250 and 300 °C). The CO2 sensing results were quite good. © 2014 by the authors; licensee MDPI, Basel, Switzerland

Low-Temperature Synthesis and Gas Sensitivity of Perovskite-Type LaCoO3 Nanoparticles

LaCoO3 nanoparticles with perovskite-type structure were prepared by a microwave-assisted colloidal method. Lanthanum nitrate, cobalt nitrate, and ethylenediamine were used as precursors and ethyl alcohol as solvent. The thermal decomposition of the precursors leads to the formation of LaCoO3 from a temperature of 500°C. The structural, morphological, and compositional properties of LaCoO3 nanoparticles were studied in this work by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM). Pellets were manufactured in order to test the gas sensing properties of LaCoO3 powders in carbon monoxide (CO) and propane (C3H8) atmospheres. Agglomerates of nanoparticles with high connectivity, forming a porous structure, were observed from SEM and TEM analysis. LaCoO3 pellets presented a high sensitivity in both CO and C3H8 at different concentrations and operating temperatures. As was expected, sensitivity increased with the gas concentration and operation temperature increase

Sensitivity of Mesoporous CoSb 2

Mesoporous CoSb2O6 nanoparticles, synthesized through a nonaqueous method (using cobalt nitrate, antimony trichloride, ethylenediamine, and ethanol as a solvent), were tested to establish their sensitivity to CO and C3H8 atmospheres at relatively low temperatures. The precursor material was dried at 200°C and calcined at 600°C. X-ray diffraction and scanning electron microscopy were employed to verify the existence of crystal phases (P42/mnm) and the morphology of this trirutile-type CoSb2O6 oxide. Pyramidal and cubic shaped crystals (average size: 41.1 nm), embedded in the material’s surface, were identified. Mesopores (average size: 6.5 nm) on the nanoparticles’ surface were observed by means of transmission electron microscopy. The best sensitivity of the CoSb2O6 in a CO atmosphere was at the relatively low temperatures of 250 and 350°C, whereas, in a C3H8 atmosphere, the sensitivity increased uniformly with temperature. These results encourage using the CoSb2O6 nanoparticles as gas sensors

Sensitivity Tests of Pellets Made from Manganese Antimonate Nanoparticles in Carbon Monoxide and Propane Atmospheres

Nanoparticles of manganese antimonate (MnSb2O6) were prepared using the microwave-assisted colloidal method for its potential application as a gas sensor. For the synthesis of the oxide, manganese nitrate, antimony chloride, ethylenediamine and ethyl alcohol (as a solvent) were used. The precursor material was calcined at 800 °C in air and analyzed by X-ray diffraction. The oxide crystallized into a hexagonal structure with spatial group P321 and cell parameters a = b = 8.8054 Å and c = 4.7229 Å. The microstructure of the material was analyzed by scanning electron microscopy (SEM), finding the growth of microrods with a size of around ~10.27 μm and some other particles with an average size of ~1.3 μm. Photoacoustic spectroscopy (PAS) studies showed that the optical energy band (Eg) of the oxide was of ~1.79 eV. Transmission electron microscopy (TEM) analyses indicated that the size of the nanoparticles was of ~29.5 nm on average. The surface area of the powders was estimated at 14.6 m2/g by the Brunauer–Emmett–Teller (BET) method. Pellets prepared from the nanoparticles were tested in carbon monoxide (CO) and propane (C3H8) atmospheres at different concentrations (0–500 ppm) and operating temperatures (100, 200 and 300 °C). The pellets were very sensitive to changes in gas concentration and temperature: the response of the material rose as the concentration and temperature increased. The results showed that the MnSb2O6 nanoparticles can be a good candidate to be used as a novel gas sensor

Facile Synthesis, Microstructure, and Gas Sensing Properties of NdCoO3 Nanoparticles

NdCoO3 nanoparticles were successfully synthesized by a simple, inexpensive, and reproducible solution method for gas sensing applications. Cobalt nitrate, neodymium nitrate, and ethylenediamine were used as precursors and distilled water as solvent. The solvent was evaporated later by means of noncontinuous microwave radiation at 290 W. The obtained precursor powders were calcined at 200, 500, 600, and 700°C in a standard atmosphere. The oxide crystallized in an orthorhombic crystal system with space group Pnma (62) and cell parameters a=5.33 Å, b=7.52 Å, and c=5.34 Å. The nanoparticles showed a diffusional growth to form a network-like structure and porous adsorption configuration. Pellets prepared from NdCoO3 were tested as gas sensors in atmospheres of carbon monoxide and propane at different temperatures. The oxide nanoparticles were clearly sensitive to changes in gas concentrations (0–300 ppm). The sensitivity increased with increasing concentration of the gases and operating temperatures (25, 100, 200, and 300°C)