Actas Del Ii Congreso Nacional De Investigacion En Edificacion Ii Congreso Nacional De Investigacion En Edificacion 15 12 2010 17 12 2010 Madrid Espana, 2010
Actas De V Congreso De La Asociacion Cientifico Tecnica Del Hormigon Estructural V Congreso De La Asociacion Cientifico Tecnica Del Hormigon Estructural 25 10 2011 27 10 2011 Barcelona Espana, 2011
ABSTRACT The adsorption of benzotriazole (BTA) on copper surfaces in 0.001, 0.005 and 0.01 M conc... more ABSTRACT The adsorption of benzotriazole (BTA) on copper surfaces in 0.001, 0.005 and 0.01 M concentrations of sulphuric acid was investigated using gravimetric measurements. BTA was tested in concentrations from 1x10-5 to 1x10-1 M at temperatures from 298 to 328 K. The adsorption mechanism is discussed in terms of applicability of the conventional Frumkin, Bockris-Swinkels and Kastening-Holleck isotherms, among others. The best fit was obtained using the Frumkin isotherm model. The projected molecular area of BTA was calculated to elucidate inhibitor orientation in the adsorption processEn el presente trabajo se estudia la adsorción del benzotriazol (BTA) sobre el cobre en solución de ácido sulfúrico con concentraciones de 0,001, 0,005 y 0,01 M utilizando medidas gravimétricas. La concentración de BTA ensayada varió de 1x10-5 M a 1x10-1 M y la temperatura de 298 K a 328 K. El mecanismo de adsorción se analiza en términos de la aplicabilidad de las isotermas convencionales de Frumkin, Bockris-Swinkels y Kastening- Holleck, entre otras. La mejor descripción de los resultados se obtuvo utilizando la isoterma de Frumkin. Para analizar la orientación del BTA en el proceso de adsorción sobre el cobre, se calculó la superficie de la molécula de BTA.
... E = 100 NxReZ -^|ReZ,^^((oJ^ReZ,,(a),)| (5) where ReZi^^x is the maximum value of the real p... more ... E = 100 NxReZ -^|ReZ,^^((oJ^ReZ,,(a),)| (5) where ReZi^^x is the maximum value of the real part of the experimental impedance data, and N is the number of points in the experimental data^^^'^ and 27] gy writing Im instead of Re in equation (5), it is possible to compare the ...
Journal of Material Cycles and Waste Management, 2015
ABSTRACT The reutilisation of MSWI natural weathered bottom ash (WBA) in many applications such a... more ABSTRACT The reutilisation of MSWI natural weathered bottom ash (WBA) in many applications such as road and underground constructions, embankments or as an aggregate replacement is a common practice in many developed countries. Its potential environmental risk has regularly been evaluated from the point of view of the leaching of heavy metals and metalloids. Nevertheless, the influence over steel rebar when reinforced concrete is exposed to the contact with WBA has been poorly assessed before. In this study, it has been possible to evaluate in terms of days the probability of corrosion in a common case of WBA reutilisation, which is in contact with reinforced concrete formulated with conventional Portland cement. The corrosion monitoring indicates that the probability of corrosion of steel rebar is higher than 90 % with a corrosion rate (CI) estimated to be 11.6 µm year−1. The aggressive conditions imposed by WBA suppose an important withdrawal if the application of reutilisation involves contact with steel rebar.
Export Date: 4 June 2013, Source: Scopus, CODEN: INQUD, Language of Original Document: Spanish, C... more Export Date: 4 June 2013, Source: Scopus, CODEN: INQUD, Language of Original Document: Spanish, Correspondence Address: Criado, M.; Centro Nacional de Investigaciones Metalúrgicas (CENIM)Spain, References: Bouzoubaa, N., Zhang, M.H., Malhotra, V.M., Golden, D.M., (1999) ACI Mater. J, 96, pp. 641-650;
ABSTRACT The main reason for the premature failure of reinforced concrete structures is corrosion... more ABSTRACT The main reason for the premature failure of reinforced concrete structures is corrosion of the reinforcements. The use of new mortars based on ternary mixtures, an alternative to ordinary Portland cement (OPC), requires extensive research in order to check its passivating properties for reinforcements and the instability or permanence of the passive state achieved. Pozzolans and slag extend the market for concrete by improving specific properties of concrete products, allowing them to be constructed with other materials or placed in environments that would have precluded the use of Portland cement alone. In properly formulated concrete mixtures, pozzolans and slag have been shown to enhance long-term strength, decrease permeability, increase durability, and reduce thermal cracking of bulk concrete. Steel reinforcements have been exposed for 13 months in mortars immersed in a 3.5% NaCl solution. The effect of mortar composition using ternary mixtures of fly-ash (FA), micro-silica (MS), and granulated blast furnace slag (GBFS) was tested. OPC was also tested as a reference. Electrochemical characterization was performed, measuring corrosion potential, linear polarization resistance, and electrochemical noise resistance. The best passivating properties were shown by the mixture of 10% FA and 10% GBFS
ABSTRACT This study reports the pickling of austenitic AISI 316L stainless steel (SS) using a mix... more ABSTRACT This study reports the pickling of austenitic AISI 316L stainless steel (SS) using a mixture of hydrogen peroxide (H2O2), sulphuric acid (H2SO4) and hydrofluoric acid (HF) at pH 2.0. The stability of H2O2 was also studied using different concentrations of ferric ion from 0 to 40 g/l and temperature from 25 to 60 °C. The pickling rate at 50 °C in the presence and absence of 40 g/l ferric ion was 2.6 and 0.2 mg/dm2 day (mdd), respectively. p-Toluene sulphonic acid was used as stabilizer of H2O2.En la presente investigación se estudia el decapado del acero inoxidable AISI 316L utilizando una mezcla de agua oxigenada (H2O2) y los ácidos sulfúrico (H2SO4) y fluorhídrico (HF) a pH 2,0. La estabilidad de la mezcla H2O2-H2SO4-HF se ha ensayado variando el contenido de iones férrico de O a 40 g/l y la temperatura de 25 a 60 °C. La velocidad de decapado a 50 °C ha sido de 2,6 y 0,2 mg/dm2 día (mdd), en ausencia y presencia de 40 g/l de iones férrico, respectivamente. Se ha utilizado el ácido p-toluen sulfónico como estabilizante del H2O2.
European Journal of Contraception and Reproductive Health Care, 2005
The aim of this paper is to study the influence of albumin content, from 5 to 45 g/L, on copper d... more The aim of this paper is to study the influence of albumin content, from 5 to 45 g/L, on copper dissolution and compounds composition in a simulated uterine solution. Experiments were performed in atmospheric pressure conditions and with an additional oxygen pressure of 0.2 atmospheres, at 6.3 and 8.0 pH values, and at a temperature of 37 +/- 0.1 degrees C for 1, 3, 7, and 30 days experimentation time. The copper dissolution rate has been determined using absorbance measurements, finding the highest value for pH 8.0, 35 g/L albumin, and with an additional oxygen pressure of 0.2 atmospheres: 674 microg/day for 1 day, and 301 microg/day for 30 days. X-ray photoelectron spectroscopy (XPS) results show copper(II) as the main copper oxidation state at pH 8.0; and copper(I) and metallic copper at pH 6.3. The presence of albumin up to 35 g/L, accelerates copper dissolution. For high albumin content a stabilisation on the copper dissolution takes place. Corrosion product layer morphology is poorly protective, showing paths through which copper ions can release.
Actas Del Ii Congreso Nacional De Investigacion En Edificacion Ii Congreso Nacional De Investigacion En Edificacion 15 12 2010 17 12 2010 Madrid Espana, 2010
Actas De V Congreso De La Asociacion Cientifico Tecnica Del Hormigon Estructural V Congreso De La Asociacion Cientifico Tecnica Del Hormigon Estructural 25 10 2011 27 10 2011 Barcelona Espana, 2011
ABSTRACT The adsorption of benzotriazole (BTA) on copper surfaces in 0.001, 0.005 and 0.01 M conc... more ABSTRACT The adsorption of benzotriazole (BTA) on copper surfaces in 0.001, 0.005 and 0.01 M concentrations of sulphuric acid was investigated using gravimetric measurements. BTA was tested in concentrations from 1x10-5 to 1x10-1 M at temperatures from 298 to 328 K. The adsorption mechanism is discussed in terms of applicability of the conventional Frumkin, Bockris-Swinkels and Kastening-Holleck isotherms, among others. The best fit was obtained using the Frumkin isotherm model. The projected molecular area of BTA was calculated to elucidate inhibitor orientation in the adsorption processEn el presente trabajo se estudia la adsorción del benzotriazol (BTA) sobre el cobre en solución de ácido sulfúrico con concentraciones de 0,001, 0,005 y 0,01 M utilizando medidas gravimétricas. La concentración de BTA ensayada varió de 1x10-5 M a 1x10-1 M y la temperatura de 298 K a 328 K. El mecanismo de adsorción se analiza en términos de la aplicabilidad de las isotermas convencionales de Frumkin, Bockris-Swinkels y Kastening- Holleck, entre otras. La mejor descripción de los resultados se obtuvo utilizando la isoterma de Frumkin. Para analizar la orientación del BTA en el proceso de adsorción sobre el cobre, se calculó la superficie de la molécula de BTA.
... E = 100 NxReZ -^|ReZ,^^((oJ^ReZ,,(a),)| (5) where ReZi^^x is the maximum value of the real p... more ... E = 100 NxReZ -^|ReZ,^^((oJ^ReZ,,(a),)| (5) where ReZi^^x is the maximum value of the real part of the experimental impedance data, and N is the number of points in the experimental data^^^'^ and 27] gy writing Im instead of Re in equation (5), it is possible to compare the ...
Journal of Material Cycles and Waste Management, 2015
ABSTRACT The reutilisation of MSWI natural weathered bottom ash (WBA) in many applications such a... more ABSTRACT The reutilisation of MSWI natural weathered bottom ash (WBA) in many applications such as road and underground constructions, embankments or as an aggregate replacement is a common practice in many developed countries. Its potential environmental risk has regularly been evaluated from the point of view of the leaching of heavy metals and metalloids. Nevertheless, the influence over steel rebar when reinforced concrete is exposed to the contact with WBA has been poorly assessed before. In this study, it has been possible to evaluate in terms of days the probability of corrosion in a common case of WBA reutilisation, which is in contact with reinforced concrete formulated with conventional Portland cement. The corrosion monitoring indicates that the probability of corrosion of steel rebar is higher than 90 % with a corrosion rate (CI) estimated to be 11.6 µm year−1. The aggressive conditions imposed by WBA suppose an important withdrawal if the application of reutilisation involves contact with steel rebar.
Export Date: 4 June 2013, Source: Scopus, CODEN: INQUD, Language of Original Document: Spanish, C... more Export Date: 4 June 2013, Source: Scopus, CODEN: INQUD, Language of Original Document: Spanish, Correspondence Address: Criado, M.; Centro Nacional de Investigaciones Metalúrgicas (CENIM)Spain, References: Bouzoubaa, N., Zhang, M.H., Malhotra, V.M., Golden, D.M., (1999) ACI Mater. J, 96, pp. 641-650;
ABSTRACT The main reason for the premature failure of reinforced concrete structures is corrosion... more ABSTRACT The main reason for the premature failure of reinforced concrete structures is corrosion of the reinforcements. The use of new mortars based on ternary mixtures, an alternative to ordinary Portland cement (OPC), requires extensive research in order to check its passivating properties for reinforcements and the instability or permanence of the passive state achieved. Pozzolans and slag extend the market for concrete by improving specific properties of concrete products, allowing them to be constructed with other materials or placed in environments that would have precluded the use of Portland cement alone. In properly formulated concrete mixtures, pozzolans and slag have been shown to enhance long-term strength, decrease permeability, increase durability, and reduce thermal cracking of bulk concrete. Steel reinforcements have been exposed for 13 months in mortars immersed in a 3.5% NaCl solution. The effect of mortar composition using ternary mixtures of fly-ash (FA), micro-silica (MS), and granulated blast furnace slag (GBFS) was tested. OPC was also tested as a reference. Electrochemical characterization was performed, measuring corrosion potential, linear polarization resistance, and electrochemical noise resistance. The best passivating properties were shown by the mixture of 10% FA and 10% GBFS
ABSTRACT This study reports the pickling of austenitic AISI 316L stainless steel (SS) using a mix... more ABSTRACT This study reports the pickling of austenitic AISI 316L stainless steel (SS) using a mixture of hydrogen peroxide (H2O2), sulphuric acid (H2SO4) and hydrofluoric acid (HF) at pH 2.0. The stability of H2O2 was also studied using different concentrations of ferric ion from 0 to 40 g/l and temperature from 25 to 60 °C. The pickling rate at 50 °C in the presence and absence of 40 g/l ferric ion was 2.6 and 0.2 mg/dm2 day (mdd), respectively. p-Toluene sulphonic acid was used as stabilizer of H2O2.En la presente investigación se estudia el decapado del acero inoxidable AISI 316L utilizando una mezcla de agua oxigenada (H2O2) y los ácidos sulfúrico (H2SO4) y fluorhídrico (HF) a pH 2,0. La estabilidad de la mezcla H2O2-H2SO4-HF se ha ensayado variando el contenido de iones férrico de O a 40 g/l y la temperatura de 25 a 60 °C. La velocidad de decapado a 50 °C ha sido de 2,6 y 0,2 mg/dm2 día (mdd), en ausencia y presencia de 40 g/l de iones férrico, respectivamente. Se ha utilizado el ácido p-toluen sulfónico como estabilizante del H2O2.
European Journal of Contraception and Reproductive Health Care, 2005
The aim of this paper is to study the influence of albumin content, from 5 to 45 g/L, on copper d... more The aim of this paper is to study the influence of albumin content, from 5 to 45 g/L, on copper dissolution and compounds composition in a simulated uterine solution. Experiments were performed in atmospheric pressure conditions and with an additional oxygen pressure of 0.2 atmospheres, at 6.3 and 8.0 pH values, and at a temperature of 37 +/- 0.1 degrees C for 1, 3, 7, and 30 days experimentation time. The copper dissolution rate has been determined using absorbance measurements, finding the highest value for pH 8.0, 35 g/L albumin, and with an additional oxygen pressure of 0.2 atmospheres: 674 microg/day for 1 day, and 301 microg/day for 30 days. X-ray photoelectron spectroscopy (XPS) results show copper(II) as the main copper oxidation state at pH 8.0; and copper(I) and metallic copper at pH 6.3. The presence of albumin up to 35 g/L, accelerates copper dissolution. For high albumin content a stabilisation on the copper dissolution takes place. Corrosion product layer morphology is poorly protective, showing paths through which copper ions can release.
Uploads
Papers by David Bastidas