José Vanderlei Martins

Large‐scale aerosol source apportionment in Amazonia

Aerosol particles were collected aboard two Brazilian Bandeirante EMB 110 planes, and the University of Washington Convair C-131A aircraft during the Smoke, Clouds, and Radiation-Brazil (SCAR-B) field project in the Amazon Basin in August and September 1995. Aerosols were collected on Nuclepore and Teflon filters. Aerosol size distribution was measured with a MOUDI cascade impactor. Sampling was performed mostly over areas heavily influenced by biomass burning smoke. Particle-induced X ray emission (PIXE) was used to measure concentrations of up to 20 elements (Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr, Zr, and Pb). Black carbon (BC) and gravimetric mass analysis were also performed. Instrumental neutron activation analysis (INAA) determined the concentrations of about 15 elements on the Teflon filters. Electron probe X ray microanalysis (EPMA) was used to analyze individual aerosol particles. The average aerosol mass concentration was 105 μg m−3, with a maximum of 297 μg m−3. Black carbon (BC) averaged 5.49 μg m−3, or 1–7% of the aerosol mass load. Five aerosol components were revealed by absolute principal factor analysis: (1) a biomass burning component (responsible for 54% of the aerosol mass and associated with BC, K, Cl, Zn, I, S, Br, Rb, aerosol mass concentration, and other elements); (2) a soil dust aerosol component (15.6% of the aerosol mass); (3) a natural biogenic component (18.7% of the aerosol mass and associated with P, K, S, Ca, Sr, Mg, Mn, Cu and Zn); (4) a second soil dust (5.7% of the aerosol mass and enriched in Si, Ti, and Fe); and (5) a NaCl aerosol component (5.9% of the aerosol mass with Na, Cl, Br, and iodine). Electron microscopy analysis of individual aerosol particles confirmed these five aerosol types. Organic material dominated the aerosol mass and the number concentration of airborne particles. Aerosol size distributions show that the fine mode accounts for 78% of the aerosol mass, centered at 0.33 μm aerodynamic diameter. The coarse mode accounts for 22% of the mass, centered at about 3.2 μm. Black carbon size distributions show a consistent picture, with a mass median diameter centered at about 0.175-0.33 μm aerodynamic diameter. This study suggests that for modeling the optical properties of aerosol in the Amazon Basin, it is essential to use a model that includes the optical and physical properties of at least two aerosol components other than the biomass burning aerosol, namely, natural biogenic aerosol and soil dust.

Fine mode aerosol composition at three long-term atmospheric monitoring sites in the Amazon Basin

The Amazon Basin tropical rain forest is a key region to study processes that are changing the composition of the global atmosphere, including the large amount of fine mode aerosol particles emitted during biomass burning that might influence the global atmosphere. Three background monitoring stations, Alta Floresta, Cuiaba, and Serra do Navio, are operating continuously measuring aerosol composition. Fine (dp < 2.0 μm) and coarse (2.0 < dp < 10 μm) mode aerosol particles were collected using stacked filter units. Particle-induced X-ray emission was used to measure concentrations of up to 20 elements in the fine mode: Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr, Zr, and Pb. Soot carbon and gravimetric mass analysis were also performed. Absolute Principal Factor Analysis (APFA) has derived absolute elemental source profiles. APFA showed four aerosol particle components: soil dust (Al, Ca, Ti, Mn, Fe), biomass burning (soot, fine mode mass concentration, K, Cl), natural primary biogenic particles with gas-to-particle component (K, S, Ca, Mn, Zn), and marine aerosol (Cl). Biogenic and biomass burning aerosol particles dominate the fine mode mass concentration, with the presence of K, P, S, Cl, Zn, Br, and fine mode mass concentration (FPM). At the Alta Floresta and Cuiaba sites, during the dry season, a strong component of biomass burning is observed. Inhalable particulate matter (dp < 10 μm) mass concentration up to 700 μg/m3 was measured. Fine particle mass concentration alone can go as high as 400 μg/m3 for large regions. The fine mode biogenic and biomass burning components show remarkable similarities in the elemental composition, even though the sampling sites are more than 3000 km apart. Fine mode sulfur concentration is entirely associated with the primary biogenic aerosol particles, with gas-to-particle conversion and the biomass burning component. Large amounts of essential plant nutrients like P are mobilized into the atmosphere and possibly lost from the Amazon Basin ecosystem by long-range transport.

Long-term monitoring of atmospheric aerosols in the Amazon Basin' Source identification and apportionment

Continuous sampling of atmospheric aerosols was carried out at two different sites in the Amazon Basin: Cuiabfi (16oS, 56oW), since July 1990, and Alta Floresta (09oS, 56oW), since August 1992. Aerosols were collected on polycarbonate filters mounted in stacked filter units (SFU). Particle-induced X ray emission (PIXE) was used to measure concentrations of up to 26 elements (Mg, A1, Si, P, S, C1, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Ge, As, Se, Br, Rb, Sr, Zr, Au, and Pb). Black carbon (BC) and gravimetric mass analyses were also performed. Inhalable particle ground concentrations showed a marked seasonality, with maxima of more than 100/zg m -3 in the dry season. The high aerosol optical thickness (AOT) values in this period (up to 4.0 at ;t = 0.440/zm) indicate that the whole air column has a significant aerosol load. Three main types of aerosol sources were identified: biomass burning, natural biogenic emissions, and soil dust resuspension. During the dry season the fine mode aerosol originated predominantly from biomass burning emissions (they were responsible for about 73% of fine aerosol mass), while the coarse mode was dominated by soil dust particles (50 to 60% of the aerosol mass). Crustal elements exhibited a unimodal coarse mode size distribution, while the pyrogenic elements showed a clear submicrometer mode. Black carbon had a submicrometer mode centered at 0.175/zm. During the wet season, biogenic aerosols were the dominant particle type and also the main source of atmospheric P in the region.

Rehabilitation robotics and serious games: An initial architecture for simultaneous players

Traditional rehabilitation treatment includes repetitive and tedious exercises for the patient. The use of computer games can motivate and engage the patients attention, making the rehabilitation process more pleasant and attractive. In this context, this paper proposes an architecture that allows multiple users to take part simultaneously on a state of the art rehabilitation process using robots and computer games. The main components of this architecture are the impedance control system adopted by the therapy robots, the client-server communication structure (Telerehabilitation server) and the human machine interface based on a serious game. Preliminary experimental tests, involving a cooperative game with two users and individual robots, clearly demonstrate how the experience of the players may be influenced by impedance control.

Analysis of atmospheric aerosols by PIXE: the importance of real time and complementary measurements

Abstract Particle-Induced X-ray Emission (PIXE) has been used for more than 30 yr in many urban and background air pollution studies. The technique has certainly contributed to the understanding of source-receptor relationship for aerosol particles as well as to aerosol physics and chemistry. In the last few years, where aerosol issues were strongly linked to global climate change through the relationship between aerosol and atmospheric radiation points to new challenges in atmospheric sciences, where PIXE could play an important role. Also the recognition for the inter-relationship between aerosol and liquid and gas phases in the atmosphere makes important to integrate PIXE aerosol analysis with other complementary measurements. The use of Nephelometers and Aethalometers to measure scattering and absorption of radiation by aerosol particles can be done in parallel with particle filter collection for PIXE analysis. Parallel measurements of trace gases using traditional monitors as well as with new techniques such as Differential Optical Absorption Spectroscopy (DOAS) that can provide concentration of O3, SO2, NO3, NO2, HCHO, HNO3, Benzene, Toluene, and Xylene, is also important for both urban and remote aerosol studies. They provide information that allows a much richer interpretation of PIXE data. Recently developed instruments that provide real time aerosol data such as the Tapered Element Oscillating Microbalance (TEOM) PM10 monitor and automatic real time organic and elemental carbon analyzers provide extremely useful data to complement PIXE aerosol analysis. The concentrations of trace elements measured by PIXE comprise only 10–30% of the aerosol mass, leaving the organic aerosol characterization and measurement with an important role. The aerosol source apportionment provided by PIXE analysis can be extended with other aerosol measurements such as scattering and absorption, estimating for example, the radiative impact of each discriminated aerosol source. The aerosol bulk PIXE measurements can be complemented with soluble concentrations provided by Ion Chromatography (IC) and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Recent developments in remote sensing techniques and products also enhance significantly regional aerosol studies. Three-dimensional air mass trajectories should be integrated in aerosol studies for urban and remote areas. The applications of these techniques to study urban aerosols from Sao Paulo and Santiago de Chile have broadened extensively the scientific scope of these studies.

A context information structure using peer-to-peer networks with the TV users

The use of context information in computer systems is becoming usual, providing many advantages in a myriad of scenarios, with TV viewing as an example. In this paper we report a structural model to manage context information captured from the users interaction, with the objective of providing ubiquitous video annotation. We also present a prototype, built as a proof of concept for our structural model, which integrates different technologies and use ontologies to represent context information. Such information, in the form of ontologies, is collected from the users direct actions, as well as from her personal information and from peer-to-peer groups of users with similar interests. These ontologies are then processed to support decision making, resulting in adaptations on how the annotations can be captured.

Knowledge discovery, rehabilitation robotics, and serious games: Examining training data

In this paper, we present an initial attempt to apply Knowledge Discovery techniques over real performance data from patients enrolled in robotic therapy in order to explore how to better optimize therapy. Performance data sets encompass measurements such as position, velocity and force, as well as final performance measures. We apply the Principal Component Analysis method in an attempt to reduce the dimensionality of the problem, molding subsets that were the input into a Multilayer Perceptron Artificial Neural Network which would carry out data mining with the purpose of discovering the relative significance of each field, in relation to a performance measure. It was possible to notice the impact caused by the lack of each field in terms of specific performance measures, indicating which data are more relevant to use in further experiments.