Brazilian Archives of Biology and Technology, 2006
Ovigerous females of Uca thayeri and U. uruguayensis were used to achieve and compare their repro... more Ovigerous females of Uca thayeri and U. uruguayensis were used to achieve and compare their reproductive pattern. The females mean size was 6.6 ± 0.8mm for U. uruguayensis and 17.3± 4.4mm for U. thayeri. The mean fecundity obtained for U. uruguayensis was 1883 ± 490 eggs (N = 27) and for U. thayeri was 31068 ± 11186 eggs (N = 31). The differences observed in reproductive pattern of U. thayeri and U. uruguayensis suggest an adaptive strategy by each species: U. thayeri presented seasonal reproduction with a pronounced intensity from January to March and higher fecundity, while U. uruguayensis reproduction was continuous all year round, but with lower fecundity.
Anilinepropylsilica xerogel was obtained by using an appropriate organosilane and tetraethyl orth... more Anilinepropylsilica xerogel was obtained by using an appropriate organosilane and tetraethyl orthosilicate as precursor reagents. The gelation was carried out using HF and NaF as catalysts. The presence of Na+ (when NaF was used) resulted in a decrease in the final organic content of the materials. This effect was interpreted as an inhibition of the organosilane polycondensation possibly due to the Na+ interaction with the SiO– groups of the hydrolyzed organosilane. The presence of Na+ also results in morphological changes in the xerogels.
... Leliz T. Arenas a , Débora SF Gay a , Celso C. Moro a , Silvio LP Dias a , Denise S. Azambuja... more ... Leliz T. Arenas a , Débora SF Gay a , Celso C. Moro a , Silvio LP Dias a , Denise S. Azambuja a , Tania MH Costa a , Edilson V. Benvenutti a , Corresponding Author Contact Information , E-mail The Corresponding Author and Yoshitaka Gushikem b. ...
A new sorbent was synthesized by anchoring 7-amino-4-azaheptyltrimetoxisilane, freshly prepared, ... more A new sorbent was synthesized by anchoring 7-amino-4-azaheptyltrimetoxisilane, freshly prepared, to silica gel, producing 7-amino-4-azaheptyl anchored silica gel (AAHSG). This material was characterized by infrared spectroscopy (IR), elemental analysis (CHN), and nitrogen adsorption-desorption isotherms. Isotherms of the adsorption of Fe3+, Fe2+ and Cu2+ on AAHSG were recorded, which indicated that Fe3+ presents a higher affinity by the sorbent. Therefore, AAHSG was successfully employed as a sorbent in a simple flow system for the preconcentration of Fe3+ in natural water samples, such as, river water, lagoonwater, springwater, stream water, well water and two water reference materials (NIST-SRM 1640, NIST-SRM 1643d). The obtained preconcentration factor was 82.2, and the detection limit achieved was 5.9 ng ml(-1). The recovery of spiked water samples ranged from 95.0 - 103.1%.
ABSTRACT The TiO2−H2O−B2O3 ternary system was studied at high pressure (7.7 GPa) and high tempera... more ABSTRACT The TiO2−H2O−B2O3 ternary system was studied at high pressure (7.7 GPa) and high temperatures, and a phase diagram is proposed. Depending on the initial stoichiometric conditions, Raman spectral analysis identified rutile, TiO2-II, H3BO3, HBO2, and B2O3 as the crystalline stable phases, and an amorphous phase constituted by B, Ti, and O. The eutectic point of this system was identified to be at around 400 °C. Two piercing points were located at around 600 and 1100 °C, identified by the stabilization of HBO2 rather than H3BO3, and B2O3 rather than HBO2, respectively. This study shows that TiB2 sintering at high pressure can be compromised by the presence of oxide-bearing phases that decrease the eutectic point of the system. This phenomenon can produce a liquid that works as a medium for transporting material, producing grain growth, which compromises the boride properties.
Brazilian Archives of Biology and Technology, 2006
Ovigerous females of Uca thayeri and U. uruguayensis were used to achieve and compare their repro... more Ovigerous females of Uca thayeri and U. uruguayensis were used to achieve and compare their reproductive pattern. The females mean size was 6.6 ± 0.8mm for U. uruguayensis and 17.3± 4.4mm for U. thayeri. The mean fecundity obtained for U. uruguayensis was 1883 ± 490 eggs (N = 27) and for U. thayeri was 31068 ± 11186 eggs (N = 31). The differences observed in reproductive pattern of U. thayeri and U. uruguayensis suggest an adaptive strategy by each species: U. thayeri presented seasonal reproduction with a pronounced intensity from January to March and higher fecundity, while U. uruguayensis reproduction was continuous all year round, but with lower fecundity.
Anilinepropylsilica xerogel was obtained by using an appropriate organosilane and tetraethyl orth... more Anilinepropylsilica xerogel was obtained by using an appropriate organosilane and tetraethyl orthosilicate as precursor reagents. The gelation was carried out using HF and NaF as catalysts. The presence of Na+ (when NaF was used) resulted in a decrease in the final organic content of the materials. This effect was interpreted as an inhibition of the organosilane polycondensation possibly due to the Na+ interaction with the SiO– groups of the hydrolyzed organosilane. The presence of Na+ also results in morphological changes in the xerogels.
... Leliz T. Arenas a , Débora SF Gay a , Celso C. Moro a , Silvio LP Dias a , Denise S. Azambuja... more ... Leliz T. Arenas a , Débora SF Gay a , Celso C. Moro a , Silvio LP Dias a , Denise S. Azambuja a , Tania MH Costa a , Edilson V. Benvenutti a , Corresponding Author Contact Information , E-mail The Corresponding Author and Yoshitaka Gushikem b. ...
A new sorbent was synthesized by anchoring 7-amino-4-azaheptyltrimetoxisilane, freshly prepared, ... more A new sorbent was synthesized by anchoring 7-amino-4-azaheptyltrimetoxisilane, freshly prepared, to silica gel, producing 7-amino-4-azaheptyl anchored silica gel (AAHSG). This material was characterized by infrared spectroscopy (IR), elemental analysis (CHN), and nitrogen adsorption-desorption isotherms. Isotherms of the adsorption of Fe3+, Fe2+ and Cu2+ on AAHSG were recorded, which indicated that Fe3+ presents a higher affinity by the sorbent. Therefore, AAHSG was successfully employed as a sorbent in a simple flow system for the preconcentration of Fe3+ in natural water samples, such as, river water, lagoonwater, springwater, stream water, well water and two water reference materials (NIST-SRM 1640, NIST-SRM 1643d). The obtained preconcentration factor was 82.2, and the detection limit achieved was 5.9 ng ml(-1). The recovery of spiked water samples ranged from 95.0 - 103.1%.
ABSTRACT The TiO2−H2O−B2O3 ternary system was studied at high pressure (7.7 GPa) and high tempera... more ABSTRACT The TiO2−H2O−B2O3 ternary system was studied at high pressure (7.7 GPa) and high temperatures, and a phase diagram is proposed. Depending on the initial stoichiometric conditions, Raman spectral analysis identified rutile, TiO2-II, H3BO3, HBO2, and B2O3 as the crystalline stable phases, and an amorphous phase constituted by B, Ti, and O. The eutectic point of this system was identified to be at around 400 °C. Two piercing points were located at around 600 and 1100 °C, identified by the stabilization of HBO2 rather than H3BO3, and B2O3 rather than HBO2, respectively. This study shows that TiB2 sintering at high pressure can be compromised by the presence of oxide-bearing phases that decrease the eutectic point of the system. This phenomenon can produce a liquid that works as a medium for transporting material, producing grain growth, which compromises the boride properties.
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