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Search Results: 1 - 10 of 298131 matches for " J. Martinelli "
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Utiliza??o de alumina para a remo??o de fluoretos em águas e efluentes
Alvarinho, S. B.;Martinelli, J. R.;
Ceramica , 2000, DOI: 10.1590/S0366-69132000000200009
Abstract: twelve different types of fluorine adsorbents based on alumina granules were produced following two processing routes. the first route consisted on the precipitation of aluminum hydroxide by sol-gel technique followed by microsphere production by internal and external gelation. aluminum nitrite was used as raw material. the second route consisted on the mechanical micro pelletization of aluminum hydroxide produced by the bayer process, and bauxite. microspheres and micropellets were heat treated at different conditions and their fluorine adsorption performance was evaluated. kinetic parameters and fluorine charge determined for those adsorbents were better than the ones reported in the literature for alumina based fluorine adsorbents. micropellet adsorbents showed similar properties when compared to the ones produced by the sol-gel technique. alumina microspheres produced by internal gelation followed by calcination at 550 oc showed the highest fluorine adsorption (100 h-1). alumina microspheres containing active coal were also produced and showed relatively high fluorine adsorption (88 h-1). alumina micropellets calcined at 400 oc showed the highest ratio of adsorbed fluorine per ton of adsorbent (27855).
Utiliza o de alumina para a remo o de fluoretos em águas e efluentes
Alvarinho S. B.,Martinelli J. R.
Ceramica , 2000,
Abstract: Foram produzidos 12 tipos de adsorventes de flúor a base de alumina granular seguindo duas rotas de processamento distintas. A primeira rota consistiu na precipita o de hidróxido de alumínio utilizando a técnica de sol-gel e a obten o de microesferas por geleifica o interna e externa. Utilizou-se como matéria prima nitrato de alumínio. A segunda rota consistiu na micropelotiza o mecanica utilizando-se hidróxido de alumínio produzido pelo processo Bayer e o uso de bauxita. Microesferas e micropelotas foram submetidas a diferentes tratamentos térmicos e avaliadas quanto ao seu desempenho no processo de adsor o de flúor em água. Os adsorventes produzidos no presente trabalho apresentaram parametros cinéticos e de carga de flúor superiores aos adsorventes de alumina reportados na literatura. Os adsorventes na forma de micropelotas apresentaram propriedades similares aos obtidos pela técnica de sol-gel. O maior valor relacionado à adsor o de flúor (100 h-1) foi obtido com microesferas de alumina produzidas pelo processo de geleifica o interna, posteriormente calcinadas a 550 oC. Microesferas de alumina contendo carv o ativo foram também preparadas e apresentaram capacidade de adsor o de flúor relativamente elevada (88 h-1). Micropelotas de alumina calcinadas a 400 oC apresentaram a maior raz o de flúor adsorvido por tonelada de adsorvente (27855).
Effects of hot isostatic pressure on titanium nitride films deposited by physical vapor deposition
Carbonari, M.J.;Martinelli, J.R.;
Materials Research , 2001, DOI: 10.1590/S1516-14392001000300004
Abstract: films of titanium nitride deposited by physical vapor deposition on 304 l stainless steel substrates were hot isostatic pressed (hip) under 150 mpa at 550 °c. to study the effects of this treatment on the microstructure of those films, x-ray diffraction analyses, rutherford backscattering spectroscopy, scanning electron microscopy, and atomic force microscopy were performed. surface hardness, and roughness were also evaluated to characterize the tin properties. the hot isostatic pressure leads to an increase of hardness for depths up to 0.1 mm and a crystallographic texture change from (111) to (200). the original tin golden color turned to red after the treatment. an increase of the grain size has been observed for hot isostatic pressed samples, but the stoichiometry of the tin film was determined to be 1:1 by rbs. the microstructure observed by atomic force microscopy indicated that the tin film surface is smoother after the hip treatment.
Dinamica Tecnológica e Ambiente Seletivo em Genética de Suínos
Júlio Eduardo Rohenkohl,Orlando Martinelli Júnior
Revista Brasileira de Inova??o , 2009,
Abstract: This article makes a discussion on the elements of the technological system in the swine geneticssegment, especially the technological trajectories and the selective environment attributes suchas the regulatory and organizational aspects. The text also identifies the recent changes in thetechnological and organizational configurations in the segment, emphasizing the arising ofnew economic agents and technological and scientific information flux.
Effects of hot isostatic pressure on titanium nitride films deposited by physical vapor deposition
Carbonari M.J.,Martinelli J.R.
Materials Research , 2001,
Abstract: Films of titanium nitride deposited by physical vapor deposition on 304 L stainless steel substrates were hot isostatic pressed (HIP) under 150 MPa at 550 °C. To study the effects of this treatment on the microstructure of those films, X-ray diffraction analyses, Rutherford Backscattering spectroscopy, scanning electron microscopy, and atomic force microscopy were performed. Surface hardness, and roughness were also evaluated to characterize the TiN properties. The hot isostatic pressure leads to an increase of hardness for depths up to 0.1 mum and a crystallographic texture change from (111) to (200). The original TiN golden color turned to red after the treatment. An increase of the grain size has been observed for hot isostatic pressed samples, but the stoichiometry of the TiN film was determined to be 1:1 by RBS. The microstructure observed by atomic force microscopy indicated that the TiN film surface is smoother after the HIP treatment.
Linear feedback control of transient energy growth and control performance limitations in subcritical plane Poiseuille flow
F. Martinelli,M. Quadrio,J. McKernan,J. F. Whidborne
Physics , 2011, DOI: 10.1063/1.3540672
Abstract: Suppression of the transient energy growth in subcritical plane Poiseuille flow via feedback control is addressed. It is assumed that the time derivative of any of the velocity components can be imposed at the walls as control input, and that full-state information is available. We show that it is impossible to design a linear state-feedback controller that leads to a closed-loop flow system without transient energy growth. In a subsequent step, full-state feedback controllers -- directly targeting the transient growth mechanism -- are designed, using a procedure based on a Linear Matrix Inequalities approach. The performance of such controllers is analyzed first in the linear case, where comparison to previously proposed linear-quadratic optimal controllers is made; further, transition thresholds are evaluated via Direct Numerical Simulations of the controlled three-dimensional Poiseuille flow against different initial conditions of physical interest, employing different velocity components as wall actuation. The present controllers are effective in increasing the transition thresholds in closed loop, with varying degree of performance depending on the initial condition and the actuation component employed.
Elevation based correction of snow coverage retrieved from satellite images to improve model calibration
C. Corbari, G. Ravazzani, J. Martinelli,M. Mancini
Hydrology and Earth System Sciences (HESS) & Discussions (HESSD) , 2009,
Abstract: The most widely used method for snow dynamic simulation relies on temperature index approach, that makes snow melt and accumulation processes depend on air temperature related parameters. A recently used approach to calibrate these parameters is to compare model results with snow coverage retrieved from satellite images. In area with complex topography and heterogeneous land cover, snow coverage may be affected by the presence of shaded area or dense forest that make pixels to be falsely classified as uncovered. These circumstances may have, in turn, an influence on calibration of model parameters. In this paper we propose a simple procedure to correct snow coverage retrieved from satellite images. We show that using raw snow coverage to calibrate snow model may lead to parameter values out of the range accepted by literature, so that the timing of snow dynamics measured at two ground stations is not correctly simulated. Moreover, when the snow model is implemented into a continuous distributed hydrological model, we show that calibration against corrected snow coverage reduces the error in the simulation of river flow in an Alpine catchment.
Snow satellite images for calibration of snow dynamic in a continuous distributed hydrological model
C. Corbari,J. Martinelli,G. Ravazzani,M. Mancini
Hydrology and Earth System Sciences Discussions , 2007,
Abstract: The snow accumulation and melt processes are well known to play an important role on the river flow regime, in particular this is enhanced for basin with complex topography where the snow dynamic is strongly affected by hillslope exposition. This paper presents a simplified numerical model for snow dynamic simulation based on air temperature thresholds that rule the snow melt and accumulation processes implemented into a continuous distributed hydrological model for hydrograph simulations at basin scale. The possibility to calibrate these temperature thresholds from snow cover maps derived from NOAA satellite images is discussed. Snow covered pixels are classified according to a procedure based on aspect and elevation of each pixel, that allows to identify snow covered pixels also in shadowed areas. Snow model performance is proved at local and basin scale. The former shows a good agreement between modelled snow dynamic and observed snow height data at the Antrona station in the Toce basin; the latter shows agreement between observed and simulated hydrographs for the three gauge stations of Toce, Ticino and Maggia rivers.
Assessing snow water equivalent of an Alpine catchment using snow dynamic model calibrated with satellite images
C. Corbari,G. Ravazzani,J. Martinelli,M. Mancini
Hydrology and Earth System Sciences Discussions , 2008,
Abstract: This paper presents a simplified numerical model of snow dynamic implemented into a continuous distributed hydrological model for hydrograph simulations at basin scale. This snow model is based on air temperature thresholds that rule the snow melt and accumulation processes. A procedure to calibrate these temperature thresholds from NOAA satellite snow cover maps is discussed. We show that, for an accurate model calibration from satellite images, it is necessary to consider the presence of areas with complex topography such as mountain slopes. Snow model performance is tested both at local and basin scale on Alpine catchment. At local scale a good agreement between modelled snow dynamic and observed snow height data at snow gauge stations in the river Anza basin (Italy) is shown; at basin scale agreement between observed and simulated hydrographs at the discharge station of river Toce (Italy) is reported.
Investigating correlations of local seismicty with anomalous geoelectrical, hydrogeological and geochemical signals jointly recorded in Basilicata Region (Southern Italy)
G. Colangelo,J. Heinicke,V. Lapenna,G. Martinelli
Annals of Geophysics , 2007, DOI: 10.4401/ag-3066
Abstract: This paper presents the preliminary results analysing the correlation between local seismicity and geoelectrical, hydrogeological and geochemical signals concomitantly recorded in Basilicata Region, one of the most seismically active areas in Southern Italy. The signals were recorded by two stations: Tito and Tramutola. Tito station measures vertically the Self-Potential field (SP) by an array of five no-polarizable electrodes equally spaced with the common electrode at 20 m depth as well as water-level, water-temperature and electrical-conductivity. Tramutola station measures self-potential signals in soil surface, gas flow and water temperature in a thermal-water well, as well as atmospheric barometric pressure and ambient temperature. Correlations were found between the sharp variability of the signals recorded by both stations and the seismic sequence that occurred on September 3 to 4, 2004, allowing us to link these anomalies with the tectonic evolution of the investigated area.
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