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The aim of this research work was to conduct a comparative study on the effectiveness of the application of chemical cleaning versus laser cleaning in the removal of surface congruent dissolution products from a potash-lime–silica historical stained-glass sample. EDTA was selected as the chemical cleaning agent. Laser cleaning was performed using a 238 fs pulse UV (343 nm) laser. The comparative cleaning studies were carried out on a stained-glass piece supplied by the Maison Lorin Glass Restoration Workshop from Chartres, France. Given the complex nature, irregular thickness and heterogeneity of the encrustations found on the glass, the two cleaning approaches were carefully performed step by step, while monitoring the process using an optical microscope. Raman spectroscopy and field emission scanning electron microscopy were used to characterize the changes induced on the sample surface during the cleaning process. The results demonstrate that the two cleaning approaches were able to eliminate the outer surface dark layer associated with carbon compounds, as well as the external part of the white layer generated by the crystallization of salts, formed with the dissolved elements after a reaction with the air. A comparison of the advantages and disadvantages of each method is also presented. [ABSTRACT FROM AUTHOR]

The study conducted demonstrates the potential of the laser zone melting method to prepare long and well-textured rectangular Bi-2212 bars. The Laser Zone Melting (LZM) offers a convenient technique to obtain textured superconductors in planar geometries within reasonably short processing times.

Pitch adapters (PAs) are passive electronic components widely used to adapt different pitches between silicon strip detectors and readout electronics. This paper presents an optimized process to fabricate high-density PAs using laser ablation of metal-on-glass layers. Minimum pitch sizes of 40 \mu \textm for the pads and 25 \mu \textm for the conductive traces were achieved. The resolution of the method allowed the cutting of traces as narrow as 15 \mu \textm . Different prototypes and small production series have been successfully manufactured and tested for electrical parameters, bondability, and metrology. Ageing tests were also performed to ensure long-term reliability. The production yield reached 80%. Fully functional particle detectors for high-energy physics have been assembled using these PAs, characterized and tested with lasers and radioactive sources. [2014-0371] [ABSTRACT FROM PUBLISHER]

ZIF-8 is an imidazolate-based metal-organic framework (MOF). ZIF-8 micromembranes of 20-32 ìm diameter are prepared by synthesizing the MOF on Nd:YAG laser-perforated 75 mm thick brass sheets (63/37 Cu/Zn). The laser irradiation activates the brass support, promoting ZIF-8 growth. A thick and continuous ZIF-8 membrane is crystallized on the laser irradiation outlet side of the support, while the inlet side and the inner surface of the microperforations are also coated with ZIF-8 intergrowth crystals. Laser perforated brass supports are not only cheap, flexible, strong, and easy to handle and to process as membrane materials; they are also chemically compatible with the ZIF-8 composition because of the shared Zn element. The ZIF-8 membranes obtained are characterized by XRD, SEM, EDX, TGA and N[2 ]sorption analysis. Furthermore, the membranes are applied to the separation of equimolar H[2]-CH[4], He-CH[4], CO[2]-CH[4] and O[2]-N[2] mixtures confirming the expected molecular sieving effect due to the MOF microporosity. [ABSTRACT FROM AUTHOR]

High Energy Physics experiments make extensive use of silicon sensors for tracking purposes. The high granularity of the modern detectors makes the connection between the segmented sensor channels and the readout electronics very complex. Furthermore, due to the mismatch between the detector pad pitch and the electronics a direct connection is not possible in most of the cases. A new method for the fabrication of pitch adapters is presented using metal-on-glass technology. In this new method the high-density metal traces are manufactured by means of laser ablation of the metal layer deposited on top of a glass substrate. This new procedure is faster, simpler and cheaper than photolithography for prototyping or low volume production. Different prototypes have been successfully manufactured and tested for electrical conductivity, bondability and metrology. Detectors have been assembled using these pitch adapters and tested in particle beams at CERN. [ABSTRACT FROM PUBLISHER]

Industrial ceramic tiles were subjected to ablation in air using a pulsed Nd:YAG laser under varying repetitive scanning and laser irradiance conditions. Two distinct photothermal ablation regimes were identified related to vaporization (<70 MW/mm2, vapor plume) and species breakdown (>70 MW/mm2, plasma plume) processes. X-ray diffraction and scanning electron microscopic studies indicated that the ablation of red clay and porcelain tiles followed different paths. Surface melting in clay tiles reduced the efficiency of ablation as the number of cycles and irradiance increased. The method enables high-definition, noncontact engraving in industrial ceramic surfaces. [ABSTRACT FROM AUTHOR]

Reactivity controlled compression ignition (RCCI) strategy uses two different fuels with different reactivities which provides more control over the combustion process and has the potential to dramatically lower combustion temperature and NOX and PM emissions. The objective of the present study is to numerically investigate the impact of syngas composition on the combustion and emissions characteristics of an RCCI engine operating with syngas/diesel at constant energy per cycle. For this purpose, different syngas compositions produced through gasification process have been chosen for comparison with the simulated syngas (mixture of hydrogen and carbon monoxide). The results obtained indicate that using syngas results in more soot, CO and UHC emissions compared with simulated syngas. Even though more NOX reduction can be achieved while operating with syngas, the engine could suffer from poor combustion and misfire at low loads due to the presence of nitrogen in the mixture. In terms of exergy, both syngas mixtures lead to more exergy destruction by the increase of syngas substitution. Nevertheless, the magnitude of exergy destruction for simulated syngas is less than the normal syngas. [ABSTRACT FROM AUTHOR]

Until recently, superhydrophobicity was considered as a hint to predict surface icephobicity, an association of concepts that is by no means universal and that has been proven to depend on different experimental factors and material properties, including the actual morphology and chemical state of surfaces. This work presents a systematic study of the wetting and freezing properties of aluminum Al6061, a common material widely used in aviation, after being subjected to nanosecond pulsed IR laser treatments to modify its surface roughness and morphology. All treated samples, independent of their surface finishing state, presented initially an unstable hydrophilic wetting behavior that naturally evolved with time to reach hydrophobicity or even superhydrophobicity. To stabilize the surface state and to bestow the samples with a permanent and stable hydrophobic character, laser-treated surfaces were covered with a thin layer of CF x prepared by plasma-enhanced chemical vapor deposition. A systematic comparison between freezing delay (FD) and wetting properties of water droplets onto these plasma-/polymer-modified laser-treated surfaces that, under conditions where a heterogeneous nucleation mechanism prevails, surface morphology rather than the actual value of the surface roughness parameter the key feature for long FD times. In particular, it is found that surface morphologies rendering a Cassie-Baxter wetting regime longer FDs than those characterized by a Wenzel-like wetting state. It is that laser treatment, with or without additional coverage with thin CF x coatings, affects wetting and ice formation behaviors and might be an efficient procedure to mitigate icing problems on metal surfaces.