368 research outputs found
Inmobilization of Zn(II) in Portland cement pastes. Determination of microstructure and leaching performance
The aim of this paper is to study the solidification/ stabilization potential of cementitious matrices on
the immobilization of Zn(II) before its disposal into the environment by determining the mechanisms of interaction between the Zn(II) ions and the binder. The results of structural and mineralogical characterization of cement pastes formed with different amounts of immobilized Zn(II) ions are presented and the study includes results from thermogravimetric analysis (TG), scanning electron
microscopy, X-ray diffraction, and leaching performance. Zn(II) ions delay the hydration reaction of Portland cement
due to the formation of mainly CaZn2(OH)6 2H2O , as well
as Zn5(CO3)2(OH)6, Zn(OH)2, and ZnCO3 in minor proportion.
Correlations between total mass loss in TG analysis
and leached Zn(II) ions in long-term curing pastes
have been obtained. This result is important because in a
preliminary approach from a TG on an early-aged cement
paste containing Zn(II), it could be possible to perform an
estimation of the amount of Zn(II) ions that could be leached,
thus avoiding costly and time-consuming tests.Mellado Romero, AM.; Borrachero Rosado, MV.; Soriano Martinez, L.; Paya Bernabeu, JJ.; Monzó Balbuena, JM. (2013). Inmobilization of Zn(II) in Portland cement pastes. Determination of microstructure and leaching performance. Journal of Thermal Analysis and Calorimetry. 112(3):1377-1389. doi:10.1007/s10973-012-2705-8S137713891123Mojumdar SC, Sain M, Prasad RC, Sun L, Venart JES. Selected thermoanalytical methods and their applications from medicine to construction, Part I. J Therm Anal Calorim. 2007;90:653–62.Perraki M, Perraki T, Kolovos K, Tsivilis S, Kakali G. Secondary raw materials in cement industry. Evaluation of their effect on the sintering and hydration processes by thermal analysis. J Therm Anal Calorim. 2002;70:143–50.Neves A, Dias Toledo R, de Moraes Rego E, Dweck J. Early stages hydration of high initial strength Portland cement. Part I. Thermogravimetric analysis on calcined mass basis. J Therm Anal Calorim. 2012;108:725–31. doi: 10.1007/s10973-012-2256-z .Balek V, Bydžovský J, Dufka A, Drochytka R, Beckman IN. Use of emanation thermal analysis to characterize microstructure development during Portland cement hydration. J Therm Anal Calorim. 2012. doi: 10.1007/s10973-012-2314-6 .Zhang Q, Ye G. Dehydration kinetics of Portland cement paste at high temperature. J Therm Anal Calorim. 2012. doi: 10.1007/s10973-012-2303-9 .Menéndez E, Vega L, Andrade C. Use of decomposition of portlandite in concrete fire as indicator of temperature progression into the material. Application to fire-affected builds. J Therm Anal Calorim. 2012. doi: 10.1007/s10973-011-2159-4 .Galan I, Andrade C, Castellote M. Thermogravimetrical analysis for monitoring carbonation of cementitious materials. Uptake of CO2 and deepening in C–S–H knowledge. J Therm Anal Calorim. 2012. doi: 10.1007/s10973-012-2466-4 .Batchelor B. Overview of waste stabilization with cement. Waste Manag (Oxford). 2006;26:689–98.Gineys N, Aouad G, Damidot D. Managing trace elements in Portland cement-Part I: interactions between cement paste and heavy metals added during mixing as soluble salts. Cem Concr Compos. 2010;32:563–70.Erdem M, Özverdi A. Environmental risk assessment and stabilization/solidification of zinc extraction residue: II. Stabilization/solidification. Hydrometallurgy. 2011;105:270–6.Nocuń-Wczelik W, Małolepszy J. Application of calorimetry in studies of the immobilization of heavy metals in cementitious materials. Thermochim Acta. 1995;269(270):613–9.Dweck J, Buchler PM, Cartledge FK. The effect of different bentonites on cement hydration during solidification/stabilization of tannery wastes. J Therm Anal Calorim. 2001;64:1011–6.Melchert MBM, Viana MM, Lemos MS, Dweck J, Buchler PM. Simultaneous solidification of two catalyst wastes and their effect on the early stages of cement hydration. J Therm Anal Calorim. 2011;105:625–33.Vessalas K, Thomas PS, Ray AS, Guerbois JP, Joyce P, Haggman J. Pozzolanic reactivity of the supplementary cementitious material pitchstone fines by thermogravimetric analysis. J Therm Anal Calorim. 2009;97:71–6.Tommaseo CE, Kersten M. Aqueous solubility diagrams for cementitious waste stabilization systems. 3. Mechanism of zinc immobilization by calcium silicate hydrate. Environ Sci Technol. 2002;36:2919–25.Peyronnard O, et al. Study of mineralogy and leaching behavior of stabilized/solidified sludge using differential acid neutralization analysis. Cem Conc Res. 2009. doi: 10.1016/j.cemconres.2009.03.016 .Moulin I, et al. Lead, zinc and chromium (III) and (VI) speciation in hydrated cement phases. International conference on the science and engineering of recycling for environmental protection, waste materials in construction (WASCON 2000), Harrogate, England, 2000, pp. 269–280.Ziegler F, Gieré R, Johnson CA. Sorption mechanisms of zinc to calcium silicate hydrate: sorption and microscopic investigations. Environ Sci Technol. 2001;35:4556–61.Qiao XC, Poon CS, Cheeseman CR. Investigation into the stabilization/solidification performance of Portland cement through cement clinker phases. J Hazard Mater. 2007;B139:238–43.Chen QY, et al. Immobilisation of heavy metal in cement-based solidification/stabilisation: a review. Waste Manag (Oxford). 2009;29:390–403.Chen QY, et al. Characterisation of products of tricalcium silicate hydration in the presence of heavy metals. J Hazard Mater. 2007;147:817–25.Fernandez-Olmo I, Chacon E, Irabien A. Influence of lead, zinc, iron (III) and chromium (III) oxides on the setting time and strength development of Portland cement. Cem Concr Res. 2001;31:1213–9.Fernandez-Olmo I, Chacon E, Irabien A. Leaching behavior of lead, chromium (III) and zinc in cement/metal oxides systems. ASCE J Environ Eng. 2003;129:532–8.Cappuyns V, Swennenb R. The application of pHstat leaching tests to assess the pH-dependent release of trace metals from soils, sediments and waste materials. J Hazard Mater. 2008;158:185–95.Payá J, Monzó J, Borrachero MV, Velázquez S. Evaluation of the pozzolanic activity of fluid catalytic cracking catalyst residue (FC3R): thermogravimetric analysis studies on FC3R-Portland cement pastes. Cem Concr Res. 2003;33:603–9.Wang S, Yang Z, Zeng L. Study of calcium zincate synthesized by solid-phase synthesis method without strong alkali. Mater Chem Phys. 2008;112:603–6.Stumm A, et al. Incorporation of zinc into calcium silicate hydrates, Part I: formation of C–S–H(I) with C/S = 2/3 and its isochemical counterpart gyrolite. Cem Concr Res. 2005;35:1665–75.Stephan D, Mallmann R, Knöfel D, Härdtl R. High intakes of Cr, Ni, and Zn in clinker, Part II. Influence on the hydration properties. Cem Concr Res. 1999;29:1959–67.Liu Y, et al. Thermal decomposition of basic zinc carbonate in nitrogen atmosphere. Thermochim Acta. 2004;414:121–3.Wahab R, et al. Synthesis and characterization of hydrozincite and its conversion into zinc oxide nanoparticles. J Alloy Compd. 2008;461:66–71.Hatakeyama T, Liu Z. Handbook of thermal analysis. New Yok: Wiley; 2000
Stellar populations of galaxies in the ALHAMBRA survey up to . I. MUFFIT: A Multi-Filter Fitting code for stellar population diagnostics
We present MUFFIT, a new generic code optimized to retrieve the main stellar
population parameters of galaxies in photometric multi-filter surveys, and we
check its reliability and feasibility with real galaxy data from the ALHAMBRA
survey. Making use of an error-weighted -test, we compare the
multi-filter fluxes of galaxies with the synthetic photometry of mixtures of
two single stellar populations at different redshifts and extinctions, to
provide through a Monte Carlo method the most likely range of stellar
population parameters (mainly ages and metallicities), extinctions, redshifts,
and stellar masses. To improve the diagnostic reliability, MUFFIT identifies
and removes from the analysis those bands that are significantly affected by
emission lines. We highlight that the retrieved age-metallicity locus for a
sample of early-type galaxies in ALHAMBRA at different stellar
mass bins are in very good agreement with the ones from SDSS spectroscopic
diagnostics. Moreover, a one-to-one comparison between the redshifts, ages,
metallicities, and stellar masses derived spectroscopically for SDSS and by
MUFFIT for ALHAMBRA reveals good qualitative agreements in all the parameters.
In addition, and using as input the results from photometric-redshift codes,
MUFFIT improves the photometric-redshift accuracy by -, and it
also detects nebular emissions in galaxies, providing physical information
about their strengths. Our results show the potential of multi-filter galaxy
data to conduct reliable stellar population studies with the appropiate
analysis techniques, as MUFFIT.Comment: 31 pages, 18 figures, accepted for publication in A&
The ALHAMBRA Survey: Bayesian Photometric Redshifts with 23 bands for 3 squared degrees
The ALHAMBRA (Advance Large Homogeneous Area Medium Band Redshift
Astronomical) survey has observed 8 different regions of the sky, including
sections of the COSMOS, DEEP2, ELAIS, GOODS-N, SDSS and Groth fields using a
new photometric system with 20 contiguous ~ filters covering the
optical range, combining them with deep imaging. The observations,
carried out with the Calar Alto 3.5m telescope using the wide field (0.25 sq.
deg FOV) optical camera LAICA and the NIR instrument Omega-2000, correspond to
~700hrs on-target science images. The photometric system was designed to
maximize the effective depth of the survey in terms of accurate spectral-type
and photo-zs estimation along with the capability of identification of
relatively faint emission lines. Here we present multicolor photometry and
photo-zs for ~438k galaxies, detected in synthetic F814W images, complete down
to I~24.5 AB, taking into account realistic noise estimates, and correcting by
PSF and aperture effects with the ColorPro software. The photometric ZP have
been calibrated using stellar transformation equations and refined internally,
using a new technique based on the highly robust photometric redshifts measured
for emission line galaxies. We calculate photometric redshifts with the BPZ2
code, which includes new empirically calibrated templates and priors. Our
photo-zs have a precision of for I<22.5 and 1.4% for
22.5<I<24.5. Precisions of less than 0.5% are reached for the brighter
spectroscopic sample, showing the potential of medium-band photometric surveys.
The global shows a mean redshift =0.56 for I=0.86 for
I<24.5 AB. The data presented here covers an effective area of 2.79 sq. deg,
split into 14 strips of 58.5'x15.5' and represents ~32 hrs of on-target.Comment: The catalog data and a full resolution version of this paper is
available at https://cloud.iaa.csic.es/alhambra
Lyman break and UV-selected galaxies at z ~ 1: II. PACS-100um/160um FIR detections
We report the PACS-100um/160um detections of a sample of 42 GALEX-selected
and FIR-detected Lyman break galaxies (LBGs) at z ~ 1 located in the COSMOS
field and analyze their ultra-violet (UV) to far-infrared (FIR) properties. The
detection of these LBGs in the FIR indicates that they have a dust content high
enough so that its emission can be directly detected. According to a spectral
energy distribution (SED) fitting with stellar population templates to their
UV-to-near-IR observed photometry, PACS-detected LBGs tend to be bigger, more
massive, dustier, redder in the UV continuum, and UV-brighter than
PACS-undetected LBGs. PACS-detected LBGs at z ~ 1 are mostly disk-like galaxies
and are located over the green-valley and red sequence of the color-magnitude
diagram of galaxies at their redshift. By using their UV and IR emission, we
find that PACS-detected LBGs tend to be less dusty and have slightly higher
total star-formation rates (SFRs) than other PACS-detected UV-selected galaxies
within their same redshift range. As a consequence of the selection effect due
to the depth of the FIR observations employed, all our PACS-detected LBGs are
LIRGs. However, none of them are in the ULIRG regime, where the FIR
observations are complete. The finding of ULIRGs-LBGs at higher redshifts
suggests an evolution of the FIR emission of LBGs with cosmic time. In an
IRX- diagram, PACS-detected LBGs at z ~ 1 tend to be located around the
relation for local starburst similarly to other UV-selected PACS-detected
galaxies at their same redshift. Consequently, the dust-correction factors
obtained with their UV continuum slope allow to determine their total SFR,
unlike at higher redshifts. However, the dust attenuation derived from UV to
NIR SED fitting overestimates the total SFR for most of our PACS-detected LBGs
in age-dependent way: the overestimation factor is higher in younger galaxies.Comment: Accepted for publication in MNRA
Additional value of screening for minor genes and copy number variants in hypertrophic cardiomyopathy
Introduction: Hypertrophic cardiomyopathy (HCM) is the most prevalent inherited heart disease. Next-generation sequencing (NGS) is the preferred genetic test, but the diagnostic value of screening for minor and candidate genes, and the role of copy number variants (CNVs) deserves further evaluation. Methods: Three hundred and eighty-seven consecutive unrelated patients with HCM were screened for genetic variants in the 5 most frequent genes (MYBPC3, MYH7, TNNT2, TNNI3 and TPM1) using Sanger sequencing (N = 84) or NGS (N = 303). In the NGS cohort we analyzed 20 additional minor or candidate genes, and applied a proprietary bioinformatics algorithm for detecting CNVs. Additionally, the rate and classification of TTN variants in HCM were compared with 427 patients without structural heart disease. Results: The percentage of patients with pathogenic/likely pathogenic (P/LP) variants in the main genes was 33.3%, without significant differences between the Sanger sequencing and NGS cohorts. The screening for 20 additional genes revealed LP variants in ACTC1, MYL2, MYL3, TNNC1, GLA and PRKAG2 in 12 patients. This approach resulted in more inconclusive tests (36.0% vs. 9.6%, p<0.001), mostly due to variants of unknown significance (VUS) in TTN. The detection rate of rare variants in TTN was not significantly different to that found in the group of patients without structural heart disease. In the NGS cohort, 4 patients (1.3%) had pathogenic CNVs: 2 deletions in MYBPC3 and 2 deletions involving the complete coding region of PLN. Conclusions: A small percentage of HCM cases without point mutations in the 5 main genes are explained by P/LP variants in minor or candidate genes and CNVs. Screening for variants in TTN in HCM patients drastically increases the number of inconclusive tests, and shows a rate of VUS that is similar to patients without structural heart disease, suggesting that this gene should not be analyzed for clinical purposes in HCM
A multiple health behaviour change intervention to prevent depression: A randomized controlled trial
Health behaviour; Major depressive disorders; Primary health care;Comportament de salut; Trastorns depressius majors; Atenció primària de salutComportamiento de salud; Trastornos depresivos mayores; Primeros auxiliosObjective: To examine the effectiveness of a 12-month MHBC intervention in the prevention of onset depression in primary health care (PHC). Methods: Twenty-two PHC centres took part in the cluster-randomized controlled trial. Patients were randomized to receive either usual care or an MHBC intervention. The endpoints were onset of major depression and reduction of depressive symptoms in participants without baseline depression at a 12-month follow-up. Results: 2531 patients agreed and were eligible to participate. At baseline, around 43% were smokers, 82% were non-adherent to the Mediterranean diet and 55% did not perform enough physical activity. The intervention group exhibited a greater positive change in two or more behaviours (OR 1.75 [95%CI: 1.17 to 2.62]; p = 0.006); any behaviour (OR 1.58 [95%CI: 1.13 to 2.20]; p = 0.007); and adherence to the Mediterranean diet (OR 1.94 [95%CI: 1.29 to 2.94]; p = 0.002), while this increase was not statistically significant for smoking and physical activity. The intervention was not effective in preventing major depression (OR 1.17; [95% CI 0.53 to 2.59)]; p =0.690) or reducing depressive symptoms (Mean difference: 0.30; [95% CI -0.77 to 1.36]; p = 0.726) during follow-up. Conclusions: As compared to usual care, the MHBC intervention provided a non-significant reduction in the incidence of major depression
Sudden Cardiac Death and Copy Number Variants: What Do We Know after 10 Years of Genetic Analysis?
Over the last ten years, analysis of copy number variants has increasingly been applied to the study of arrhythmogenic pathologies associated with sudden death, mainly due to significant advances in the field of massive genetic sequencing. Nevertheless, few published reports have focused on the prevalence of copy number variants associated with sudden cardiac death. As a result, the frequency of these genetic alterations in arrhythmogenic diseases as well as their genetic interpretation and clinical translation has not been established. This review summarizes the current available data concerning copy number variants in sudden cardiac death-related diseases
A Ks-band-selected catalogue of objects in the ALHAMBRA survey
The original ALHAMBRA catalogue contained over 400,000 galaxies selected using a synthetic F814W image, to the magnitude limit AB(F814W)24.5. Given the photometric redshift depth of the ALHAMBRA multiband data (=0.86) and the approximately -band selection, there is a noticeable bias against red objects at moderate redshift. We avoid this bias by creating a new catalogue selected in the band. This newly obtained catalogue is certainly shallower in terms of apparent magnitude, but deeper in terms of redshift, with a significant population of red objects at . We select objects using the band images, which reach an approximate AB magnitude limit . We generate masks and derive completeness functions to characterize the sample. We have tested the quality of the photometry and photometric redshifts using both internal and external checks. Our final catalogue includes sources down to , with a significant tail towards high redshift. We have checked that there is a large sample of objects with spectral energy distributions that correspond to that of massive, passively evolving galaxies at , reaching as far as . We have tested the possibility of combining our data with deep infrared observations at longer wavelengths, particularly Spitzer IRAC data
- …