Determinación de sodio en agua mediante espectroscopia de plasmas producidos por láser

En el presente trabajo, la técnica Espectroscopia de plasmas producidos por láser (Laser-induced breakdown spectroscopy -LIBS-) se aplicó a la determinación cuantitativa de Na en agua natural dulce, de interés en agricultura para el estudio de la alcalinidad de aguas de regadío. Para efectuar el análisis, se prepararon soluciones con concentraciones conocidas del analito, se mezclaron con óxido de calcio y se compactaron en pastillas sólidas. Los plasmas se produjeron en aire a presión atmosférica utilizando un láser pulsado Nd:YAG. Se construyó una curva de calibración y se calculó el límite de detección. Se analizaron muestras de agua natural y los resultados se compararon con los obtenidos mediante espectroscopia de absorción atómica. Se demostró la factibilidad del método para la determinación de Na en agua natural dulce.In the present work, Laser-induced breakdown spectroscopy (LIBS) was applied to quantitative determination of Na in fresh water, of interest to agriculture for the study of alkalinity in irrigation water. To perform the analysis, liquid solutions were prepared with known concentrations of the analyte, mixed with calcium oxide and pressed into solid pellets. The plasmas were generated in air at atmospheric pressure using a pulsed Nd:YAG laser. A calibration curve was constructed and the limit of detection was calcu- lated. Fresh water samples were analyzed and the results were compared with those obtained by atomic absorption spectroscopy, demonstrating the feasibility of the method for determination of Na in fresh water.Fil: Garcimuño, Mayra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires, Argentina;Fil: Diaz Pace, Diego Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires, Argentina

τ–algorithm for gathering spectroscopic information by modelling emission line shapes: Application to laser–induced plasmas

In this work, a fitting algorithm was implemented and applied to analyze emission line shapes in laser-induced breakdown spectroscopy. By modeling emission spectral lines, the optical thickness was calculated for each line of interest and the intensity line profileswere computed and matched to measured spectra. The algorithm was applied to analyze the experimental profiles of a hydrogenH_ line at 6562.8 Å, and the resonant lines of Mg II at 2795.5 Å and at 2802.7 Å. Spectroscopic information was obtained about the physical processes occurring in the plasma, such as self-absorption and Stark broadening. The results demonstrated the potential of the developed method to provide valuable information in plasma spectroscopy for both fundamental and applied research.Fil: Diaz Pace, Diego Martin. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; ArgentinaFil: Molina, Juan Carlos. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentin

Experimental Stark widths and shifts of V II spectral lines

We have measured the Stark widths and shifts of V II spectral lines in the wavelength range 2000-4200 Å belonging to 75 multiplets. The spectra are emitted by laser-induced plasmas generated from fused glass discs prepared by borate fusion. The electron density and temperature are in the ranges (0.72-6.5) × 1017 cm-3 and (11 000-14 900) K, respectively. To avoid self-absorption, we have used seven samples with vanadium concentrations selected by the CSigma graph methodology. This has allowed to include strong and weak lines in the study, including resonance and forbidden lines. The experimental widths and shifts are compared with theoretical values available in the literature.Fil: Manrique Rosel, Javier. Universidad CEU San Pablo; EspañaFil: Diaz Pace, Diego Martin. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; ArgentinaFil: Aragón, Concepción. Universidad Publica de Navarra. Departamento de Ciencias.; EspañaFil: Aguilera Andoaga, Jose antonio. Universidad Publica de Navarra. Departamento de Ciencias.; Españ

Rapid monitoring of heavy metals in fluvial sediments using laser-induced breakdown spectroscopy

In this work, a quantitative analysis of heavy metals Cr and Cu in fluvial sediments was carried out by Laser-induced breakdown Spectroscopy (LIBS) to assess the anthropogenic. To perform the analysis, different sediment samples were collected at selected positions. Standard addition calibration curves were constructed for Cr and Cu by measuring the Cr I line at 357.87 nm and Cu I line at 324.75 nm. The moisture and organic matter contents of the sediments were taken into account to overcome the matrix effect. The quantitative models were evaluated statistically to evaluate the robustness and prediction ability of the method. Low values for root-mean-square errors for calibration (RMSEC), prediction (RMSEP) and cross-validation (RMSECV) were calculated. High values of the correlation coefficients of calibration (Rc2 = 0:984 for Cr; Rc2= 0:986 for Cu) and cross-validation (Rcv2 = 0:985 for Cr; Rcv2 = 0:981 for Cu) were obtained. The calculated limits of detection (LoD) were 2.9 ppm for Cr and 3.3 ppm for Cu, and the limits of quantification (LoQ) were 9.5 ppm for Cr and 11 ppm for Cu. Concentrations of Cr and Cu higher than the baseline values were obtained in the sediments downstream (Cr: 49 ppm, Cu: 81 ppm) which are indicative of the pollution of the basin by heavy metals due to the spill of untreated effluents derived from anthropogenic activities. LIBS analysis was optimized for reliable heavy metal monitoring in fluvial sediments.Fil: Martino, Lucila Juliana. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; ArgentinaFil: D'angelo, Cristian Adrián. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; ArgentinaFil: Rodriguez, Corina Iris. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Humanas. Departamento de Ciencias Ambientales. Centro de Investigación y Estudios Ambientales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Diaz Pace, Diego Martin. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentin

Assessment of sorption capability of montmorillonite clay for lead removal from water using laser–induced breakdown spectroscopy and atomic absorption spectroscopy

Laser-induced breakdown spectroscopy (LIBS) and atomic absorption spectroscopy (AAS) techniques were applied for quantitative analysis of the remaining Pb content in water samples after treatment with a raw montmorillonite (MMT) and an organic derivative (MMO) clays for heavy metal removal, an issue of crucial importance for decontamination of water bodies. The Pb sorption capabilities of MMT and MMO clays were assessed by using solutions with known Pb concentrations, in the range 100-500 ppm. To carry out the LIBS analysis, the samples were prepared in the form of solid pellets with powdered calcium hydroxide addition. The measurement conditions were optimized to achieve reliable analytical results and the plasma parameters, i.e., temperature and electron density, were obtained. For quantification purpose, a calibration curve was constructed with the Pb I emission line at 4057.8 Å measured at the time window 30-45 μs by using reference samples with Pb concentrations in the range 56-715 ppm. The Pb residual content in the liquid samples determined with LIBS showed a good agreement with those measured with AAS. The sorption efficiency of Pb from contaminated water was calculated through a sorption percentage SPb%. The calculated SPb% was higher for MMT (56%-100%) than for MMO (27%-47%). The results also demonstrated the usefulness of LIBS method for the determination of Pb concentrations in liquid samples.Fil: Teran, Ezequiel Jesús. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; ArgentinaFil: Montes, María Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Rodriguez, Corina Iris. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Humanas. Departamento de Ciencias Ambientales. Centro de Investigación y Estudios Ambientales; ArgentinaFil: Martino, Lucila Juliana. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; ArgentinaFil: Quiroga, Miguel Angel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; ArgentinaFil: Landa, Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; ArgentinaFil: Torres Sanchez, Rosa Maria. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Tecnología de Recursos Minerales y Cerámica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Tecnología de Recursos Minerales y Cerámica; ArgentinaFil: Diaz Pace, Diego Martin. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentin

First narrow-band search for continuous gravitational waves from known pulsars in advanced detector data

Spinning neutron stars asymmetric with respect to their rotation axis are potential sources of continuous gravitational waves for ground-based interferometric detectors. In the case of known pulsars a fully coherent search, based on matched filtering, which uses the position and rotational parameters obtained from electromagnetic observations, can be carried out. Matched filtering maximizes the signalto- noise (SNR) ratio, but a large sensitivity loss is expected in case of even a very small mismatch between the assumed and the true signal parameters. For this reason, narrow-band analysis methods have been developed, allowing a fully coherent search for gravitational waves from known pulsars over a fraction of a hertz and several spin-down values. In this paper we describe a narrow-band search of 11 pulsars using data from Advanced LIGO’s first observing run. Although we have found several initial outliers, further studies show no significant evidence for the presence of a gravitational wave signal. Finally, we have placed upper limits on the signal strain amplitude lower than the spin-down limit for 5 of the 11 targets over the bands searched; in the case of J1813-1749 the spin-down limit has been beaten for the first time. For an additional 3 targets, the median upper limit across the search bands is below the spin-down limit. This is the most sensitive narrow-band search for continuous gravitational waves carried out so far

Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M>70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0<e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

Search for gravitational-lensing signatures in the full third observing run of the LIGO-Virgo network

Gravitational lensing by massive objects along the line of sight to the source causes distortions of gravitational wave-signals; such distortions may reveal information about fundamental physics, cosmology and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO--Virgo network. We search for repeated signals from strong lensing by 1) performing targeted searches for subthreshold signals, 2) calculating the degree of overlap amongst the intrinsic parameters and sky location of pairs of signals, 3) comparing the similarities of the spectrograms amongst pairs of signals, and 4) performing dual-signal Bayesian analysis that takes into account selection effects and astrophysical knowledge. We also search for distortions to the gravitational waveform caused by 1) frequency-independent phase shifts in strongly lensed images, and 2) frequency-dependent modulation of the amplitude and phase due to point masses. None of these searches yields significant evidence for lensing. Finally, we use the non-detection of gravitational-wave lensing to constrain the lensing rate based on the latest merger-rate estimates and the fraction of dark matter composed of compact objects