Artículos LEHhttp://hdl.handle.net/10259.4/25522024-03-29T15:43:04Z2024-03-29T15:43:04ZSub-ns-pulsed laser cleaning of an archaeological bone from the Sierra de Atapuerca, Spain: a case studyRahman, Md. AshiqurFuente Leis, Germán F. de laCarretero Díaz, José MiguelMaingi, Evan MainaAlonso Abad, Mª PilarAlonso Alcalde, RodrigoChapoulie, RémySchiavon, NickAngurel Lámban, Luis Albertohttp://hdl.handle.net/10259/79372023-11-07T01:05:28Z2021-11-01T00:00:00ZSub-ns-pulsed laser cleaning of an archaeological bone from the Sierra de Atapuerca, Spain: a case study
Rahman, Md. Ashiqur; Fuente Leis, Germán F. de la; Carretero Díaz, José Miguel; Maingi, Evan Maina; Alonso Abad, Mª Pilar; Alonso Alcalde, Rodrigo; Chapoulie, Rémy; Schiavon, Nick; Angurel Lámban, Luis Alberto
Controlled laser irradiation parameters using recently developed sub-nanosecond pulsed laser technology with emission wavelength in the near Infrared regime (1064 nm) have been assessed on a Pleistocene bone from the archaeological site of Sierra de Atapuerca, Spain. Burst pulse mode was employed to explore contaminant removal efciency, while at the same time, assessing the degree of damage produced to the underlying original substrate surface. The surface morphology and composition of the deteriorated bone have been characterized, along with the efects of laser irradiation at 1064 nm, using Optical Microscopy (OM), Scanning Electron Microscopy–with Energy Dispersive X-ray Spectrometry (SEM–EDS), and X-ray Photoelectron Spectroscopy (XPS). The most efective laser cleaning parameters in burst mode have been identifed in order to optimize the emission parameters of the laser, thus localizing its interaction within the outermost layers of contaminants and degradation products, avoiding damage to the underlying original bone surface. Hence, threshold cleaning and substrate damage values have been determined for this new sub-ns laser, paving the way to safer laser cleaning procedures that may be useful for the efective conservation of bone archaeological artifacts.
2021-11-01T00:00:00ZUltra-Short Pulse Laser Cleaning of Contaminated Pleistocene Bone: A Comprehensive Study on the Influence of Pulse Duration and WavelengthRahman, Md. AshiqurFuente Leis, Germán F. de laCarretero Díaz, José MiguelAlonso Abad, Mª PilarAlonso Alcalde, RodrigoChapoulie, RémySchiavon, NickAngurel Lámban, Luis Albertohttp://hdl.handle.net/10259/79262023-11-04T01:05:27Z2023-02-01T00:00:00ZUltra-Short Pulse Laser Cleaning of Contaminated Pleistocene Bone: A Comprehensive Study on the Influence of Pulse Duration and Wavelength
Rahman, Md. Ashiqur; Fuente Leis, Germán F. de la; Carretero Díaz, José Miguel; Alonso Abad, Mª Pilar; Alonso Alcalde, Rodrigo; Chapoulie, Rémy; Schiavon, Nick; Angurel Lámban, Luis Alberto
The impact of wavelength and pulse duration in laser cleaning of hard blackish contaminants crust from archaeologically significant Pleistocene bone is investigated in this research. The objective is to determine the practical cleaning procedures and identify adequate laser parameters for cleaning archaeological bone from Sima de los Huesos (Spain) based on conservation and restoration perspectives. Bone surface cleaning was performed utilizing two Q-switched Nd:YAG lasers: subnanosecond pulsed lasers with emission wavelengths at 355 nm and 1064 nm, respectively, and a Yb:KGW femtosecond pulsed laser with an emission wavelength in the third harmonic at 343 nm. In all experiments, the laser beam scanning mode was applied to measure cleaning efficiency in removing contaminants and degradation products while assessing the underlying substrate surface damage. Several properties, including wavelength-dependent absorption, pulse repetition rate, and thermal properties of the material, are analyzed when evaluating the ability of these lasers to boost the cleaning efficiency of the deteriorated bone surface. Bone surface morphology and composition were studied and compared before and after laser irradiation, using Optical Microscopy, Scanning Electron Microscopy with Energy Dispersive X-ray Spectrometry (SEM-EDS), Fourier Transform Infrared Spectroscopy (FTIR), and X-ray Photoelectron Spectroscopy (XPS) characterization methods. The results indicate that 238-femtosecond UV laser irradiation with 2.37 TWcm−2 is significantly safer and more efficient toward surface contaminant desorption than sub-nanosecond laser irradiation. The results herein presented suggest that these types of fs lasers may be considered for realistic laser conservation of valuable historic and archaeological museum artifacts.
2023-02-01T00:00:00ZUltrashort pulsed Femtosecond UV laser for selective cleaning of significant Cretaceous flintsRahman, Md. AshiqurFuente Leis, Germán F. de laCarretero Díaz, José MiguelAlonso Abad, Mª PilarNavazo Ruiz, MartaAlonso Alcalde, RodrigoChapoulie, RémySchiavon, NickAngurel Lámban, Luis Albertohttp://hdl.handle.net/10259/78722023-10-17T00:05:32Z2023-05-01T00:00:00ZUltrashort pulsed Femtosecond UV laser for selective cleaning of significant Cretaceous flints
Rahman, Md. Ashiqur; Fuente Leis, Germán F. de la; Carretero Díaz, José Miguel; Alonso Abad, Mª Pilar; Navazo Ruiz, Marta; Alonso Alcalde, Rodrigo; Chapoulie, Rémy; Schiavon, Nick; Angurel Lámban, Luis Alberto
This work reports on studies aimed to evaluate the utilization of ultrashort 238 fs (fs) pulsed UV laser emission at 343 nm for eliminating colored crusts and surface deposits on significant Cretaceous flint surfaces, in an attempt to safeguard its aesthetic appearance and archaeological value. The results indicate that fs UV lasers may be an ideal, non-contact tool for selective surface cleaning of sensitive archaeological artefacts, since they enable contaminant desorption while avoiding photothermal damage.
2023-05-01T00:00:00ZNorthwest African Neolithic initiated by migrants from Iberia and LevantSimões, Luciana G.Günther, TorstenMartínez-Sánchez, Rafael M.Vera-Rodríguez, Juan CarlosIriarte Avilés, EnekoRodríguez-Varela, RicardoBokbot, YoussefValdiosera Morales, Cristina EugeniaJakobsson, MattiasJakobssonhttp://hdl.handle.net/10259/76982023-06-09T00:05:23Z2023-06-01T00:00:00ZNorthwest African Neolithic initiated by migrants from Iberia and Levant
Simões, Luciana G.; Günther, Torsten; Martínez-Sánchez, Rafael M.; Vera-Rodríguez, Juan Carlos; Iriarte Avilés, Eneko; Rodríguez-Varela, Ricardo; Bokbot, Youssef; Valdiosera Morales, Cristina Eugenia; Jakobsson, Mattias; Jakobsson
In northwestern Africa, lifestyle transitioned from foraging to food production around 7,400 years ago but what sparked that change remains unclear. Archaeological data support conflicting views: (1) that migrant European Neolithic farmers brought the new way of life to North Africa1,2,3 or (2) that local hunter-gatherers adopted technological innovations4,5. The latter view is also supported by archaeogenetic data6. Here we fill key chronological and archaeogenetic gaps for the Maghreb, from Epipalaeolithic to Middle Neolithic, by sequencing the genomes of nine individuals (to between 45.8- and 0.2-fold genome coverage). Notably, we trace 8,000 years of population continuity and isolation from the Upper Palaeolithic, via the Epipaleolithic, to some Maghrebi Neolithic farming groups. However, remains from the earliest Neolithic contexts showed mostly European Neolithic ancestry. We suggest that farming was introduced by European migrants and was then rapidly adopted by local groups. During the Middle Neolithic a new ancestry from the Levant appears in the Maghreb, coinciding with the arrival of pastoralism in the region, and all three ancestries blend together during the Late Neolithic. Our results show ancestry shifts in the Neolithization of northwestern Africa that probably mirrored a heterogeneous economic and cultural landscape, in a more multifaceted process than observed in other regions.
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