scholarly journals Observation of the Laser Cleaning Effect on the Gotland Sandstone Elemental Composition

2006 ◽  
Vol 2006 ◽  
pp. 1-6 ◽  
Author(s):  
Marta Jasińska ◽  
Jørn Bredal-Jørgensen ◽  
Gerard Śliwiński
Keyword(s):  
Elemental Composition ◽  
Laser Irradiation ◽  
Surface Cleaning ◽  
Laser Cleaning ◽  
Laser Surface ◽  
Stone Surface ◽  
Initial Value ◽  
Surface Destruction ◽  
Initial Content

Changes of the elemental composition due to laser surface cleaning of a naturally crusted historical sandstone were investigated by means of the SEM/EDX technique. Data obtained for stone samples prior to and after laser irradiation were compared with those for noncrusted, reference ones. It has been observed that the crust removal resulting from ablative cleaning was accompanied by a decrease of the partial content of elements Al, S, K, Ca, and Mg in the range of 60–80% of their initial value recorded for the noncleaned, crust-covered stone surface. In the stone layer just under the crust coverage, a structure characterized by intergranular spaces between the SiO2 grains being the main sandstone component filled with degraded binder was observed. From the coincidence of the binder destruction and chemical composition of the crust, the stone surface destruction due to the long-term interaction of environmental pollution was deduced. The spatial distributions of individual elements obtained by mapping after laser irradiation indicated that besides SiO2 the content of elemental components in the sandstone surface layer decreased by 50%, whereas for Fe with the initial content of 4% and other surface remnants: P, Ti, Zn, and Cl—all below 1%, insignificant changes were only revealed. It was concluded in agreement with the literature that surface cleaning by means of the 1064 nm laser does not cause removal of iron from the sandstone surface.

Automatic Control and Real-Time Monitoring of Laser Cleaning and Laser Ablation

1998 ◽  
Vol 526 ◽  
Author(s):  
Y.F. Lu ◽  
M. Meng ◽  
M.H. Hong ◽  
T.S. Low ◽  
D.S.H. Chan
Keyword(s):  
Control System ◽  
Automatic Control ◽  
Real Time ◽  
Excimer Laser ◽  
Automatic Control System ◽  
Surface Cleaning ◽  
Laser Cleaning ◽  
Laser Surface ◽  
Feedback Signal ◽  
Real Time Monitoring

AbstractClosed-loop control and real-time monitoring of pulsed excimer laser cleaning and ablation have been realised by software and hardware design and development. The audible acoustic wave generated during excimer laser surface cleaning and ablation has been used as the feedback signal for the automatic control system of laser-surface interaction. Man–machine interface for laser operation and acoustic monitoring has been developed with LabVIEW 4.1 under Windows 95 environment. This system has been used to control and monitor laser cleaning and ablation processes in real-time and proven to successfully meet the requirements in our study. By database exchange, this automatic control system can also be applied to control drilling and materials removing.

Real-Time Monitoring for Laser Surface Cleaning

1994 ◽  
Vol 354 ◽  
Author(s):  
Y.F. Lu ◽  
M.H. Hong ◽  
Y. Aoyagi
Keyword(s):  
Acoustic Wave ◽  
Real Time ◽  
Laser Irradiation ◽  
Frequency Spectrum ◽  
Acoustic Waves ◽  
Surface Condition ◽  
Surface Cleaning ◽  
Laser Cleaning ◽  
Cleaning Process ◽  
Real Time Monitoring

AbstractReal-time monitoring of surface cleanness in laser dry cleaning was investigated by monitoring the acoustic waves emitted from the substrate surface under pulsed laser irradiation. It is found that the acoustic wave from the surface under laser irradiation can reflect the surface condition, i.e., the surface cleanness. Besides the surface condition, the acoustic waveforms also depend on the substrate materials and laser pulse energies (intensities). The frequency spectrum obtained from the Fourier transform can provide clear indication for different surface cleanness. Removing of surface contaminants can generally result in weaker laser-induced acoustic wave and change in the frequency spectrum. The surface cleanness, therefore, can be monitored in real-time by detecting the amplitude and frequency of the acoustic wave during the laser cleaning process. This phenomenon provides the laser cleaning technique a real-time feedback during the cleaning process.

scholarly journals Accumulation of Elements in Biodeposits on the Stone Surface in Urban Environment. Case Studies from Saint Petersburg, Russia

2020 ◽  
Vol 9 (1) ◽  
pp. 36
Author(s):  
Katerina V. Sazanova (nee Barinova) ◽  
Marina S. Zelenskaya ◽  
Vera V. Manurtdinova ◽  
Alina R. Izatulina ◽  
Aleksei V. Rusakov ◽  
...  
Keyword(s):  
Microbial Community ◽  
Optical Microscopy ◽  
Elemental Composition ◽  
Urban Environment ◽  
Microbial Metabolites ◽  
Stone Surface ◽  
Saint Petersburg ◽  
Icp Ms ◽  
Living Organisms ◽  
Selective Accumulation

The pattern of elements accumulation in biodeposits formed by living organisms and extracellular products of their metabolism (biofouling, primary soils) on different bedrocks (of the monuments of Historical necropoleis in Saint Petersburg) were studied by a complex of biological and mineralogical methods (optical microscopy, SEM, EDX, XRD, ICP MS, XRFS). The content of 46 elements in biodeposits with various communities of microorganisms is determined. The model recreating the picture of the input and selective accumulation of elements in biodeposits on the stone surface in outdoor conditions is assumed. It is shown that the main contribution to the elemental composition of biodeposits is made by the environment and the composition of the microbial community. The contribution of leaching under the action of microbial metabolites of mineral grains, entering biodeposits from the environment, is significantly greater than that of the underlying rock.

scholarly journals Severe Corneal Morphological Alterations after Excimer Laser Surface Ablation for a High Astigmatism

2021 ◽  
pp. 492-496
Author(s):  
Anna M. Roszkowska ◽  
Giovanni W. Oliverio ◽  
Giuseppe A. Signorino ◽  
Mario Urso ◽  
Pasquale Aragona
Keyword(s):  
Excimer Laser ◽  
Corneal Stroma ◽  
Corneal Topography ◽  
Laser Surface ◽  
Slit Lamp ◽  
Slit Lamp Examination ◽  
Morphological Alterations ◽  
Surface Ablation ◽  
Confocal Images

We report long-term alterations of anterior corneal stroma after excimer laser surface ablation for a high astigmatism. The patient claimed progressive visual loss in his right eye (RE) during the last 3 years after bilateral laser-assisted subepithelial keratectomy (LASEK) surgery. His examination comprised visual acuity (UDVA and CDVA), slit-lamp examination, corneal topography and tomography, AS-OCT, and confocal microscopy. The UDVA was 0.1 in his RE and 1.0 in the left eye. The CDVA in the RE was 0.8. The slit-lamp examination showed a stromal lesion in the inferior paracentral corneal zone, with multiple vertical tissue bridges and severe thinning. Corneal topography and tomography showed central flattening with inferior steepening and severe alteration in elevation maps. AS-OCT showed void areas in the anterior stroma with thinning of the underlying tissue, and confocal images were not specific. In this case, progressive corneal steepening and thinning that manifest topographically as inferior ectasia occurred in correspondence to the singular stromal alterations after LASEK.

Acoustic Emission in Laser Surface Cleaning for Real-Time Monitoring

1995 ◽  
Vol 34 (Part 2, No. 11B) ◽  
pp. L1557-L1560 ◽  
Author(s):  
Yong-Feng Lu ◽  
Yoshinobu Aoyagi
Keyword(s):  
Acoustic Emission ◽  
Real Time ◽  
Surface Cleaning ◽  
Laser Surface ◽  
Real Time Monitoring

Surface Cleaning Challenges for Organic Light Emitting Diodes

2021 ◽  
Vol 314 ◽  
pp. 3-8
Author(s):  
Noel Giebink
Keyword(s):  
Light Emitting Diodes ◽  
Surface Cleaning ◽  
Organic Light Emitting Diodes ◽  
Large Area ◽  
Light Emitting ◽  
Organic Light ◽  
Organic Optoelectronic Devices ◽  
Soft Thin Film ◽  
Organic Optoelectronic

Organic optoelectronic devices such as light-emitting diodes and solar cells present unique challenges for surface cleaning and preparation because of their large area and the ‘soft’, thin film nature of the materials involved. This paper gives an introduction to this class of semiconductor devices and covers a recent example of how surface cleaning impacts the long-term reliability of organic light-emitting diodes being commercialized for solid-state lighting.

Argon laser irradiation of the semicircular canal in two patients with benign paroxysmal positional vertigo

2002 ◽  
Vol 116 (9) ◽  
pp. 723-725 ◽  
Author(s):  
Yasuya Nomura
Keyword(s):  
Laser Irradiation ◽  
Benign Paroxysmal Positional Vertigo ◽  
Semicircular Canals ◽  
Argon Laser ◽  
Laser Device ◽  
Positional Vertigo ◽  
Long Term Follow Up ◽  
Paroxysmal Positional Vertigo

The results of long-term follow-up after surgical treatment of two patients with intractable benign paroxysmal positional vertigo are reported. Argon laser irradiation of the blue-lined posterior and lateral semicircular canals in one patient, and of only the posterior canal in the other was performed seven and six years ago, respectively. Argon laser irradiation was carried out 10 times in succession three mm along the canal to occlude it. The power applied each time was 1.5.W on the dial of the laser device for 0.5.sec. Relief of vertigo was noted on the second post-irradiation day. There has been no recurrence of vertigo in these patients.

scholarly journals Evaluation of Soil S Pools under 23 Years of Maize Monoculture

Agronomy ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2376
Author(s):  
Pavel Suran ◽  
Martin Kulhánek ◽  
Jiří Balík ◽  
Jindřich Černý ◽  
Ondřej Sedlář
Keyword(s):  
High Dose ◽  
The Czech Republic ◽  
S Uptake ◽  
Biomass Yields ◽  
Entire Experiment ◽  
Initial Content ◽  
Phosphorus And Potassium ◽  
Very High ◽  
Sulfur Nutrition

Sulfur nutrition is a critical part of proper crop growth and development. In our study, biomass yields (BY) and S uptake were investigated on long-term maize monoculture on haplic luvisol soil during the 23 years of this trial, as well as changes in water extractable (Sw), adsorbed (Sads), mineral (Sav), and pseudo-total S (St) fractions. Treatments used in this study are: (1) Control (Cont); (2) ammonium sulfate (AS); (3) urea and ammonium nitrate (UAN); (4) UAN + phosphorus and potassium (UAN + PK); (5) UAN + phosphorus, magnesium, sulfur (UAN + PMgS); and (6) Fallow. Recently, the Mehlich 3 method started to be used in the Czech Republic to determine content of plant available S. Using this method, it was found that the content of S extracted by Mehlich 3 (SM3) closely correlates to Sav in both topsoil and subsoil (r = 0.958 in 1997 and 0.990 in 2019, both at p < 0.001). We also found that, on average, during the entire experiment, all treatments had increased yields over Cont (135–147%) and increased S uptake (291, 192, 180, and 246% of Cont for AS, UAN, UAN + PK, and UAN + PMgS, respectively). Examining the changes from 1997 to 2019 in topsoil (0–30 cm depth), we discovered a decrease of S content in Sw, Sads, Sav, and St fractions on all treatments to an average of 34.6%, 65.8%, 42.2%, and 78.6% of their initial values. The exception was AS treatment, which doubled its initial content in mineral fractions and maintained the same levels of St, and which we attribute to the very high dose of S on this treatment (142 kg ha−1 year−1). Using the simple balance method, AS and UAN + PMgS treatments lost 142.2 and 95.3 kg S ha−1 year−1 to other sinks, except plant uptake, from the entire soil profile (0–60 cm) during 23 years of experiment. Other treatments also show significant losses with the exception of Fallow. Given these results, it is clear that content of sulfur in soil is generally decreasing and attention should be paid mainly towards minimizing of its losses.

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