Remote Laser-Induced Breakdown Spectroscopy in Underwater Archaeology: Identification of Chemical Fingerprints in Shipwrecks

Nowadays, one of the most important areas of interest in archeology is the characterization of the submersed cultural heritage. Mediterranean Sea is rich in archaeological findings due to storms, accidents and naval battles since prehistoric times. Chemical analysis of submerged materials is an extremely valuable source of information on the origin and precedence of the wrecks, and also the raw materials employed during the manufacturing of the objects found in these sites. Sometimes extracting the archeological material from the marine environment is not practical due to the size of the sample, or is not permitted by the legislation or preservation practices. In these cases, the in-situ analysis turns into the only alternative. The versatility of laser-induced breakdown spectroscopy (LIBS) has been successfully tested in oceanography 1. Advantages such as rapid and in situ analysis with no sample preparation make LIBS a suitable alternative for field measurements. A fiber-optics-based remote instrument has been designed for the recognition and identification of artworks in underwater archaeological shipwrecks. The LIBS prototype featured both single-pulse (SP-LIBS) and multi-pulse excitation (MP-LIBS). The use of multi-pulse excitation allowed an increased laser beam energy (up to 95 mJ) transmitted through the optical fiber. This excitation mode results in an improved performance of the equipment in terms of extended range of analysis (to a depth of 50 m) and a broader variety of samples to be analyzed (i.e., rocks, marble, ceramics and concrete). In this work, parametric studies in the laboratory such as gas flow pressure, beam focal conditions and angle of incidence, among others, were performed to optimize the best conditions for field analysis. Finally, results obtained in these field trials confirmed the capability of remote LIBS for in-situ analysis of underwater archeological samples.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Libs in cultural heritage: recognition and identification of objects in an underwater archaeological shipwreck

Nowadays, one of the most important areas of interest in archeology is the characterization of the submersed cultural heritage. Mediterranean Sea is rich in archaeological findings due to storms, accidents and naval battles since prehistoric times. Chemical analysis of submerged materials is an extremely valuable source of information on the origin and precedence of the wrecks, and also the raw materials employed during the manufacturing of the objects found in these sites. Nevertheless, sometimes it is not possible to extract the archaeological material from the marine environment due to size of the sample, the legislation or preservation purposes. In these cases, the in-situ analysis turns into the only alternative for obtaining information. In spite of this demand, no analytical techniques are available for the in-situ chemical characterization of underwater materials. The versatility of laser-induced breakdown spectroscopy (LIBS) has been successfully tested in oceanography 1. Advantages such as rapid and in situ analysis with no sample preparation make LIBS a suitable alternative for field measurements. To further exploit the inherent advantages of the technology, a mobile fiber-based LIBS platform capable of performing remote measurements up to 50 meters range has been designed for the recognition and identification of artworks in underwater archaeological shipwrecks. The LIBS prototype featured both single-pulse (SP-LIBS) and multi-pulse excitation (MP-LIBS) 2. The use of multi-pulse excitation allowed an increased laser beam energy (up to 95 mJ) transmitted through the optical fiber. This excitation mode results in an improved performance of the equipment in terms of extended range of analysis (to a depth of 50 m) and a broader variety of samples to be analyzed (i.e., rocks, marble, ceramics and concrete). In the present work, the design and construction considerations of the instrument are reported and its performance is discussed on the basis of the spectral response, the remote irradiance achieved upon the range of analysis and its influence on plasma properties, as well as the effect of the laser pulse duration and purge gas to the LIBS signal. Also, to check the reliability and reproducibility of the instrument for field analysis several robustness tests were performed outside the lab. Finally, the capability of this instrument was successfully demonstrated in an underwater archaeological shipwreck (San Pedro de Alcántara, Malaga).Universidad de Málaga. Campus de Excelencia Internacional Andalucí

Chemical Fingerprints in an Underwater Archaeological Shipwreck using a Remote Laser-Induced Breakdown Spectroscopy System

Nowadays, one of the most important areas of interest in archeology is the characterization of the submersed cultural heritage. Mediterranean Sea is rich in archaeological findings due to storms, accidents and naval battles since prehistoric times. Chemical analysis of submerged materials is an extremely valuable source of information on the origin and precedence of the wrecks, and also the raw materials employed during the manufacturing of the objects found in these sites. Sometimes extracting the archeological material from the marine environment is not practical due to the size of the sample, or is not permitted by the legislation or preservation practices. In these cases, the in-situ analysis turns into the only alternative. The versatility of laser-induced breakdown spectroscopy (LIBS) has been successfully tested in oceanography [1]. Advantages such as rapid and in situ analysis with no sample preparation make LIBS a suitable alternative for field measurements. A fiber-optics-based remote instrument has been designed for the recognition and identification of artworks in underwater archaeological shipwrecks. The LIBS prototype featured both single-pulse (SP-LIBS) and multipulse excitation (MP-LIBS). The use of multi-pulse excitation allowed an increased laser beam energy (up to 95 mJ) transmitted through the optical fiber. This excitation mode results in an improved performance of the equipment in terms of extended range of analysis (to a depth of 50 m) and a broader variefy of samples to be analyzed (i.e., rocks, marble, ceramics and concrete). In this work, parametric studies in the laboratory such as gas flow pressure, beam focal conditions and angle of incidence, among others, were performed to optimize the best conditions for field analysis. Finally, results obtained in these field trials confirmed the capability of remole LIBS for in-situ analysis of underwater archeological samples.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Characterization of Laser-Induced Plasmas Of Organic Compounds by spatially- and temporally resolved optical emission spectrometry

The large majority of laser-induced plasmas experiments are performed on metals in air at atmospheric pressure, where recombination mechanisms do not play a significant role, as the primary emission lines of interest are significantly more intense than those derived from recombination with air, particularly those yielding oxides. Due to the large number of electronic transitions commonly attainable on metals, many intense emission lines are recorded and different regions of interest useful for identification and quantification purposes may be assigned. The main difficulties in the interpretation of the molecular emission of species containing C, N, O or H relies on the questions concerning their origin: direct release from native bonds or recombination with ambient constituents. In other words: does the resultant spectrum mimic the structure of a molecule or the molecular information gets lost in the course of the secondary reactions? Considering that the spectrum observed is always a convolution of primary and secondary processes, experiments in vacuum or in controlled atmospheres may help to address such questions. The present work shows detailed experiments where spatially- and temporally-resolved optical emission spectroscopy of laser-produced plasmas on organic compounds has been performed. The experiments cover a pressure range from 1000 mbar to 10-3 mbar that allows a precise observation of the effect of the surrounding atmosphere in the formation of species by recombination.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Femtosecond time-resolved phase-change microscopy and ablation threshold calculations to understand ultrafast laser ablation

El trabajo recoge experimentos realizados en una configuración sonda-prueba haciendo uso de un láser de femtosegundos, con el objetivo de comprender los fenómenos de ablación de materiales sólidos ras irradiación con láseres de pulso ultracorto.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Supervisión pedagógica y las competencias profesionales según los docentes de las instituciones educativas Pamer Lima Metropolitana. 2015

A continuación presentamos una síntesis de la investigación “ Supervisión pedagógica y las competencias profesionales según los docentes de las instituciones educativas Pamer Lima Metropolitana. 2015 ”. El objetivo de la investigación estuvo dirigido a determinar la relación entre la supervisión pedagógica y las competencias profesionales según los docentes de las instituciones educativas Pamer Lima Metropolitana 2015. La investigación es de tipo básico, el nivel es descriptivo correlacional y el diseño utilizado es no experimental, de corte transversal. La muestra que se seleccionó es de tipo censal, conformada por los ciento cuarenta (140) docentes de las Instituciones Educativas Pamer. Lima Metropolitana. Para recolectar los datos se utilizaron los instrumentos de supervisión pedagógica y de competencias profesionales. El procesamiento de datos se realizó con el software SPSS (versión 22). Realizado el análisis descriptivo y la correlación a través del coeficiente de Rho de Spearman, con un resultado de Rho=0,421, interpretándose como moderada relación, con una ρ = 0.00 (p < 0.05), con el cual se rechaza la hipótesis nula por lo tanto los resultados señalan que existe relación directa y significativa entre la supervisión pedagógica y las competencias profesionales

Autoeficacia percibida, estrategias metacognitivas y desempeño académico de los estudiantes de la Escuela Profesional de Medicina de la Universidad Nacional Jorge Basadre Grohmann, 2019

El objetivo del estudio fue establecer la relación entre la autoeficacia percibida y las estrategias metagnotivas que utilizan los estudiantes de la Escuela Profesional de Medicina de la Universidad Nacional Jorge Basadre Grohmann con su desempeño académico en 2019. Metodología: diseño no experimental, transversal, relacional. Población: 201 estudiantes. Tamaño y tipo de muestreo:132 unidades de análisis , aleatorio estratificado. Instrumentos: Escala de autoeficacia general de 10 ítems y Cuestionario de estrategias metacognitivas de 20 items. Resultados: el 53% presenta una percepción de autoeficaia alta y un 40,2% autoeficacia moderada; predomina el nivel bajo de desarrollo de estrategias metacognitivas con un 25,4% y el nivel alto con un 20,4%. El promedio de desempeño académico es de 12,08 (DT 1,91) lo que se corresponde con el predominio de un nivel de desempeño académico medio con el 76,5%. Conclusión: la autoeficacia percibida y las estrategias metacognitivas se relacionan significativamente con el desempeño académico de los estudiantes de la Escuela Profesional de Medicina de la Universidad Nacional Jorge Basadre Grohmann en el 2019 ( p<0,001).Tesi

Temporal and energetic scale of solid matter interaction phenomena occurring during femtosecond ablation of solids

Ablation using femtosecond lasers exhibits significant differences with that at the nanosecond timescale, where the concurrence of photochemical and photothermal processes taking place during the photon absorption govern the process. In the ultrashort regime, the several phenomena involved in the laser-matter interaction are markedly different. Thus, a prior comprehension of the processes is required in order to extend the range of current applications and improve the analytical results. Our current studies are facing fundamental and applied studies with the aim of better understanding laser-matter interaction processes in condensed phase using femtosecond lasers. To achieve this goal, we have designed experimental strategies expecting to improve the knowledge of the timescale and onset generation of chemical species and surface alterations during femtosecond ablation of solids. Time-resolved optical emission spectroscopy, time-of-flight mass spectrometry and time-resolved phase-change microscopy are currently implemented. The combined use of the cited techniques is allowing the experimental determination of the energy threshold, temporal regime and macroscopic effects occurring in a variety of materials as a consequence of the interaction with an ultra-short laser pulse. The core of the experiment is a 80 Mhz, 100 nJ, 400 fs Ti-Saphire oscillator that is additionally subjected to chirped pulse amplification to produce an output of 3,5 mJ at 35 fs and a maximum repletion rate of 1 KHz. Different wavelengths (800, 400 and 266 nm) are achievable. An intensified CCD and a dual-state reflectron equipped with a cassegrain reflective optics are used for the analysis of the photons and ion generated after laser irradiation. Additionally, a pump-probe microscope with a temporal resolution better than 500 fs has been designed to allow time-resolved studies of phase-change in the ablated samples.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Ejecución Presupuestal y Gestión por Resultados en el Gobierno Regional de Ayacucho - 2018

El presente trabajo investigativo denominado: Ejecución Presupuestal y Gestión por Resultados en el Gobierno Regional de Ayacucho - 2018; en los últimos años el presupuesto de los Gobiernos Regionales ha tenido un incremento notable. sin embargo, todos los Gobiernos Regionales del Perú, han revertido los presupuestos asignados por falta de capacidad de gasto. De acuerdo a la Memoria Anual de Gestión 2018, se aprecia que, en la ejecución física financiera para gastos de capital a nivel pliego 2018, tuvo un Presupuesto Institucional Modificado para proyectos (Gastos de capital), de S/ 445,208,888, se devengó S/ 385,280,466.69, que representa el 86.54%, por tanto, la entidad ha dejado de ejecutar S/ 59,928,421.31, generando una gestión deficiente. El problema principal: ¿Qué relación existe entre la Ejecución Presupuestal y la Gestión por Resultados en el Gobierno Regional de Ayacucho – 2018?, objetivo: Determinar qué relación existe entre la Ejecución Presupuestal y la Gestión por Resultados en el Gobierno Regional de Ayacucho – 2018. La metodología utilizada es específico y general, aplicada, con un nivel correlacional, con diseño correlacional descriptivo, no experimental; como técnica empleada la encuesta y el instrumento fue el cuestionario. El resultado es: que existe una relación positiva y significativa entre la Ejecución Presupuestal y la gestión por resultados en el Gobierno de Ayacucho – 2018 y la principal recomendación es: Socializar con los directivos, personal y funcionarios con la finalidad de ejecutar la mayor cantidad de presupuesto en obras en beneficio de la población previa una adecuada planificación

Differential laser-matter interaction in the ablation of solid samples with laser pulses in the interval between 35 fs – 4 ps.

Our communication is focused on the influence of the pulse width in the laser-matter interaction during laser ablation of solid materials. The experiments were performed with an 80 MHz, 100 nJ, 400 fs Ti-Saphire oscillator, amplified to produce an output of 3,5 mJ at 35 fs and a maximum repletion rate of 1 KHz. Modifications in the stretcher-compressor have allowed the continuous selection of amplified pulses in the range between 35 fs to 4 ps. The pulses are subjected to measurements in the autocorrelation, spectral bandwidth and energy per pulse. A 0.5 m focal-length spectrograph fitted with an intensified CCD or fast single-channel detectors is used to determine the time constants, to establish the fluence threshold, and to record multi-channel spectra from the generated plasmas. Additionally, morphological characterization making use of optical and electron microscopy were performed. The effect of the longer laser pulses in the laser-matter interaction - particularly in the extension of the heat-affected zone - and its implication in depth-profiling studies was also checked. For such purpose, a layered sample with a defined structure was analyzed by laser-induced breakdown spectroscopy under different pulse widths conditions. The effect on the averaged ablation rate, depth resolution and layer mixing will be commented.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech