The Experts below are selected from a list of 57 Experts worldwide ranked by ideXlab platform
C. P. Bergmann - One of the best experts on this subject based on the ideXlab platform.
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Transport of Ca^+2 and $${{\rm SO}_{4}^{-2}}$$ ions in Porous Media of Clay Product and its Association with the Efflorescence Phenomenon
Transport in Porous Media, 2011Co-Authors: C. C. Ferreira, C. P. BergmannAbstract:This study investigates the displacement of $${{\rm SO}_{4}^{-2}}$$ and Ca^+2 ions in a red-Clay ceramic, simulating the process of efflorescence. Ceramic bodies were molded (70 × 27 × 9 mm^3) by vacuum extrusion formulated with different contents of CaSO_4 · 2H_2O (0, 2, 4, 8, and 16% in weight) and burnt at different temperatures (800, 850, 900, and 950°C) for 12 h. Ceramic bodies were characterized in terms of water absorption, apparent porosity, and pore size distribution. Efflorescence was evaluated according to the norms of ASTM C67/2003 and by testing the solubilization of $${{\rm SO}_{4}^{-2}}$$ and Ca^+2 ions after 1 h with the ceramic bodies immersed in hot water as well as after 7, 14, and 28 consecutive days with the ceramic bodies immersed in cold water. In the quantification of efflorescence, a new image analysis methodology was developed by using the graphic software Image Tools 3.0. The results allowed in establishing a relationship between the efflorescence of the investigated ions, physical properties (water absorption and apparent porosity), pore size distribution, and solubilization.
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transport of ca 2 and rm so _ 4 2 ions in porous media of Clay Product and its association with the efflorescence phenomenon
Transport in Porous Media, 2010Co-Authors: C. C. Ferreira, C. P. BergmannAbstract:This study investigates the displacement of \({{\rm SO}_{4}^{-2}}\) and Ca+2 ions in a red-Clay ceramic, simulating the process of efflorescence. Ceramic bodies were molded (70 × 27 × 9mm3) by vacuum extrusion formulated with different contents of CaSO4· 2H2O (0, 2, 4, 8, and 16% in weight) and burnt at different temperatures (800, 850, 900, and 950°C) for 12 h. Ceramic bodies were characterized in terms of water absorption, apparent porosity and pore size distribution. Efflorescence was evaluated according to the norms of ASTM C67/2003 and by testing the solubilization of \({{\rm SO}_{4}^{-2}}\) and Ca+2 ions after 1 h with the ceramic bodies immersed in hot water as well as after 7, 14, and 28 consecutive days with the ceramic bodies immersed in cold water. In the quantification of efflorescence, a new image analysis methodology was developed by using the graphic software Image Tools 3.0. The results allowed in establishing a relationship between the efflorescence of the investigated ions, physical properties (water absorption and apparent porosity), pore size distribution, and solubilization.
C. C. Ferreira - One of the best experts on this subject based on the ideXlab platform.
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Transport of Ca^+2 and $${{\rm SO}_{4}^{-2}}$$ ions in Porous Media of Clay Product and its Association with the Efflorescence Phenomenon
Transport in Porous Media, 2011Co-Authors: C. C. Ferreira, C. P. BergmannAbstract:This study investigates the displacement of $${{\rm SO}_{4}^{-2}}$$ and Ca^+2 ions in a red-Clay ceramic, simulating the process of efflorescence. Ceramic bodies were molded (70 × 27 × 9 mm^3) by vacuum extrusion formulated with different contents of CaSO_4 · 2H_2O (0, 2, 4, 8, and 16% in weight) and burnt at different temperatures (800, 850, 900, and 950°C) for 12 h. Ceramic bodies were characterized in terms of water absorption, apparent porosity, and pore size distribution. Efflorescence was evaluated according to the norms of ASTM C67/2003 and by testing the solubilization of $${{\rm SO}_{4}^{-2}}$$ and Ca^+2 ions after 1 h with the ceramic bodies immersed in hot water as well as after 7, 14, and 28 consecutive days with the ceramic bodies immersed in cold water. In the quantification of efflorescence, a new image analysis methodology was developed by using the graphic software Image Tools 3.0. The results allowed in establishing a relationship between the efflorescence of the investigated ions, physical properties (water absorption and apparent porosity), pore size distribution, and solubilization.
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transport of ca 2 and rm so _ 4 2 ions in porous media of Clay Product and its association with the efflorescence phenomenon
Transport in Porous Media, 2010Co-Authors: C. C. Ferreira, C. P. BergmannAbstract:This study investigates the displacement of \({{\rm SO}_{4}^{-2}}\) and Ca+2 ions in a red-Clay ceramic, simulating the process of efflorescence. Ceramic bodies were molded (70 × 27 × 9mm3) by vacuum extrusion formulated with different contents of CaSO4· 2H2O (0, 2, 4, 8, and 16% in weight) and burnt at different temperatures (800, 850, 900, and 950°C) for 12 h. Ceramic bodies were characterized in terms of water absorption, apparent porosity and pore size distribution. Efflorescence was evaluated according to the norms of ASTM C67/2003 and by testing the solubilization of \({{\rm SO}_{4}^{-2}}\) and Ca+2 ions after 1 h with the ceramic bodies immersed in hot water as well as after 7, 14, and 28 consecutive days with the ceramic bodies immersed in cold water. In the quantification of efflorescence, a new image analysis methodology was developed by using the graphic software Image Tools 3.0. The results allowed in establishing a relationship between the efflorescence of the investigated ions, physical properties (water absorption and apparent porosity), pore size distribution, and solubilization.
Mohamed Bagane - One of the best experts on this subject based on the ideXlab platform.
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Investigation of the effect of temperature on Tunisian Clay Product during drying process
Heat and Mass Transfer, 2020Co-Authors: Nouha Jhider, Mohamed BaganeAbstract:The aim of this work was to evaluate the influence of drying temperature on the convective drying process of Clay sample as well as on the effective diffusivity. The study was performed on Tunisian raw-Clay Product in here simple spherical geometry with initial moisture content of 0.35 kg water/kg d.b. Air-drying characteristics were investigated in a laboratory convective dryer for a temperature range varying from 30 to 60 °C at a constant air velocity of 1,44 m/s with an air humidity ratio of 50%. Four analytical solutions based on Fick’s and Crank’s diffusion equations were proposed to describe the drying process. The first and the second equations neglected shrinkage effect while the two other equations consider it as a fundamental parameter. According to the obtained results, it was proved that the increase in air temperature increases the drying rate, as well as the effective diffusion coefficients. Based on the analytical solutions used in this study, it was concluded that the model including the shrinkage effect gives the lowest value of the effective diffusion coefficient.
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moisture sorption isotherms and isosteric heat of sorption of tunisian Clay Product
Heat and Mass Transfer, 2019Co-Authors: Nouha Jhider, Mohamed BaganeAbstract:The aim of this study was to determine the adsorption and desorption isotherms of Tunisian Clay Product at different temperatures with a water activity varying from 10.95 to 97% using the statistic gravimetric method, which is an important step to evaluate its hygroscopic character. It was found that when temperature increases, Clay material becomes less hygroscopic due to physical and/or chemical changes in Product. Ten mathematical models were used to fit experimental data of sorption isotherms. The fitting of the model to experimental data was evaluated with the correlation coefficient (R2) and the root mean square error (RMSE). The Oswin model was determined to be the best model for describing experimental data of adsorption and desorption in the investigated ranges of temperature and water activity. The net isosteric heat of sorption determined from sorption isotherms estimated from Oswin model and using Clausius-Clapeyron equation decreased continuously with increasing the equilibrium moisture content.
Per Ambus - One of the best experts on this subject based on the ideXlab platform.
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Methane Oxidation in Pig and Cattle Slurry Storages, and Effects of Surface Crust Moisture and Methane Availability
Nutrient Cycling in Agroecosystems, 2006Co-Authors: Søren O. Petersen, Per AmbusAbstract:Storages with liquid manure (slurry) may develop a surface crust of particulate organic matter, or an artificial crust can be established. Slurry storages are net sources of atmospheric methane (CH_4), but a potential for bacterial oxidation of CH_4 in surface crusts was recently suggested in a study of experimental storages. The present study was conducted to investigate methanotrophic activity under practical storage conditions. Surface crusts from slurry storages at two pig farms and four dairy farms were sampled in late autumn. Mixed samples (0–4 cm depth) were used to determine changes in CH_4, O_2 and CO_2 during incubation, while intact subsamples were used to characterize CH_4 oxidation as a function of CH_4 availability and moisture content. Methane oxidation was observed in all materials except for an expanded Clay Product (Leca) sampled from a pig slurry storage. Despite significant variation between replicate subsamples, there was a significant increase in methanotrophic activity when CH_4 concentrations increased from 500 to 50,000 ppmv. Maximum fluxes ranged from −1 to −4.5 g CH_4 m^−2 d^−1. Surface crust samples were partly dried and then re-wetted in four steps to the original moisture content, each time followed by determination of CH_4 fluxes. Only one surface crust material showed a relationship between CH_4 fluxes and moisture content that would implicate gas diffusivity in the regulation of CH_4 oxidation. The occurrence of inducible CH_4 oxidation activity in slurry storage surface crusts indicates that there is a potential for stimulating the process by manipulation of gas phase composition above the stored slurry.
Susan J. Clearwater - One of the best experts on this subject based on the ideXlab platform.
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Measuring sub-lethal effects on freshwater crayfish (Paranephrops planifrons) behaviour and physiology: laboratory and in situ exposure to modified zeolite
Hydrobiologia, 2011Co-Authors: Stephanie M. Parkyn, Christopher W. Hickey, Susan J. ClearwaterAbstract:Various behavioural and physiological tests were applied to determine whether an aluminised modified zeolite Clay Product (Z2G1), used to cap phosphorus release from lake sediments, had sub-lethal effects on adult freshwater crayfish ( Paranephrops planifrons ). In situ exposures of caged crayfish before and after application of modified zeolite to Lake Okaro, Central North Island, New Zealand, at a nominal application concentration of 350 g m^−2, did not impact the survival of freshwater crayfish or produce any significant sub-lethal effects on crayfish mobility or physiology that we could detect. In laboratory sediment tests, crayfish did not show any consistent effect from short-term (10 days) exposure to modified zeolite (at concentrations of 350, 700 or 2,100 g m^−2) or to alum. When combined, the field and laboratory data provide strong evidence that applications of 350 g m^−2 modified zeolite will have no short-term effect on adult crayfish, with a ‘margin of safety’ for higher application rates. Chronic exposure effects of capping agents and the indirect impacts of lake treatment (e.g. food web responses) are yet to be determined. Quantitative measures of shade- and shelter-seeking behaviour, righting behaviour, and length of escape response, could be improved by the addition of standardised behavioural observations. Physiological measures of ammoniacal-N Production and oxygen consumption are less variable than behavioural tests, but comparisons between treatments are best conducted simultaneously. A suite of behavioural and physiological sub-lethal measures using field and laboratory exposures is recommended to provide an integrated assessment of crayfish health.