The aim of the present work was to develop a method for the remote assessment of the impact of fire and drought stress on Mediterranean forest species such as the cork oak (Quercus suber) and maritime pine (Pinus pinaster). The proposed method is based on laser induced fluorescence (LIF): chlorophyll fluo rescence is remotely excited by frequency doubled YAG:Nd laser radiation pulses and collected and analyzed using a telescope and a gated high sensitivity spectrometer. The plant health criterion used is based on the I 685 /I 740 ratio value, calculated from the fluorescence spectra. The method was benchmarked by comparing the results achieved with those obtained by conventional, continuous excitation fluorometric method and water loss gravimetric measurements. The results obtained with both methods show a strong correlation between them and with the weight loss measurements, showing that the proposed method is suitable for fire and drought impact assessment on these two species.
The purpose of the present study was to evaluate the flexural strength of specimens made of nickel-chromium (Ni-Cr) and cobalt-chromium (Co-Cr) alloys and joined by tungsten inert gas (TIG) welding and conventional brazing. Ni–Cr and Co–Cr base metal specimens (n = 40, each) were cast and welded by TIG or brazing. The specimens were divided into six groups (2 base metals, four welded specimens). Ceramic systems were applied to the central part of all the specimens. A three-point bending test with a velocity of 0.5 mm/m was performed on the specimens up to the point of the first ceramic bond failure by measuring the flexural strength. Data were analyzed using two-way ANOVA and Bonferroni’s tests. Conventional welding showed the lowest flexural strength results for both alloys, while the TIG weld and the control group presented with varying bond strengths for the alloys studied. We concluded that TIG welding was superior to the conventional welding method for both Ni–Cr and Co–Cr alloys with regard to the flexural strength of the ceramic.
Aim: The aim of this study was to evaluate the influence of tungsten inert gas (TIG) welding and airborne particle abrasion using aluminum oxide particles on the flexural strength of a joint between ceramic and cobalt-chromium alloys. Methods: The specimens were cast and welded using TIG, then divided into 6 groups (n = 10) and subjected to blasting with 250 μm, 100 μm, and 50 μm aluminum oxide particles. Ceramic systems were applied to the central part of all specimens. A three-point bending test using a velocity of 0.5 mm/m was performed on the specimens to measure flexural strength. Data were analyzed using two-way analysis of variance and Tukey’s test. Results: TIG welding demonstrated the lowest resistance compared with the non-welded groups. Airborne particle abrasion using 250 μm aluminum oxide particles demonstrated greater resistance in the welded groups (p < 0.05). Mixed faults were found in all specimens. Conclusion: TIG welding decreased the bond strength, and the particle size of aluminum oxide did not affect the metal-ceramic bond in groups without TIG welding.
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