Laser to fight fire?

2020 ◽  
Vol 18 (5) ◽  
pp. 455-456
Author(s):  
Khaled Moustafa, PhD
Keyword(s):  
Laser Irradiation ◽  
Laser Intensity ◽  
Empirical Studies ◽  
Organic Matters ◽  
Narrow Zone ◽  
Laser Devices

Wildfires spread as long as burnable organic matters fuel them, such as grasses and trees. When there is nothing more to burn, fires will put out naturally. Here, I would propose to fight “fire by fire” or by Laser using specific Laser devices to immediately and punctually carbonize a narrow zone in front of crawling wildfires to create a protective area that will stop fires from further propagation when the fire reaches the Laser-carbonized zone. Empirical studies will be required to determine the best conditions of Laser intensity, wavelength, and period of Laser irradiation that would be required to only carbonize organic matters in narrow targeted zone without spreading fire further.

Fabrication of High Density Silicon Nano-Dots by Excimer Laser Irradiation on Block Copolymer Masks

2007 ◽  
Author(s):  
Dae Up Ahn ◽  
Erol Sancaktar
Keyword(s):  
Laser Ablation ◽  
Block Copolymer ◽  
Laser Irradiation ◽  
Excimer Laser ◽  
Ablation Threshold ◽  
Laser Intensity ◽  
Selective Etching ◽  
Time Duration ◽  
Excimer Laser Ablation ◽  
Excimer Laser Irradiation

We report easy and fast fabrication methods to prepare densely packed polystyrene (PS) and silicon nano-dots using one-step excimer laser irradiation on cylindrically nanopatterned block copolymer materials, without any additional selective etching steps before a non-selective etching. Preferential etching in more ultraviolet (UV)-sensitive block component, and non-selective removal of all block components allowed transferring nanopatterns in block copolymer masks to inorganic silicon substrates, when an appropriate laser intensity was used. Surface melt flows of block components, which severely undermine the initial orders of nanopatterns in a block copolymer mask, were observed at the laser intensity near the ablation threshold of the less UV-sensitive component. Thus, in order to obtain mask-image-like topographic nanopatterns on the target material surfaces, the intensity of excimer laser radiation should be sufficiently lower than the ablation threshold of the less UV-sensitive component as long as the intensity is higher than that of the more UV-sensitive component. Numerical analyses on the photothermal excimer laser ablation in binary mixture systems predicted the presence of a matrix-assisted excimer laser ablation in the less UV-sensitive component at the laser intensity lower than its ablation threshold, owing to the heat conduction from the more UV-sensitive component during the nanoscopic level of time duration.

Formation of Electro-Conductive Part on Polymeric Material Surface by CO2 Laser Irradiation

2011 ◽  
Author(s):  
Takushi Saito ◽  
Tatsuya Kawaguchi ◽  
Isao Satoh
Keyword(s):  
Electrical Conductivity ◽  
Laser Irradiation ◽  
Polymeric Material ◽  
Carbon Dioxide Laser ◽  
Laser Intensity ◽  
Material Surface ◽  
Small Disk ◽  
Electrically Conductive ◽  
Higher Temperature ◽  
Property Changes

In this study, a method to directly form an electrically conductive layer on the surface of polymeric material by using infrared laser irradiation was investigated. Polyacrylonitrile, which was shaped into a small disk 20 mm in diameter and 5 mm thick, was used as a test specimen. The conditions for pyrolysis were obtained by referencing the conditions for commercial carbon fiber. First, the specimen was processed in air at a relatively low temperature (around 250°C) for the stabilization treatment (i.e., fireproofing), then its surface was heated at a higher temperature (above 1000°C) for the carbonization treatment (i.e., graphitizing). Both an infrared furnace and a carbon dioxide laser were used as heating devices to find optimal conditions. Property changes in the material due to the thermal treatment were measured using Fourier transform infrared spectroscopy, and the electrical conductivity of the carbonized surface was measured using a four-probe method. The results showed that an electrical conductivity of 11.4 S/cm (siemens per centimeter) was achieved with a laser intensity of 8.6 W/cm2 for 5 min for the stabilization, and a laser intensity of 34 W/cm2 for 10 s for the carbonization.

Laser-Induced Deformation Patterns in Thin Films and Surfaces

1999 ◽  
Vol 121 (2) ◽  
pp. 182-188 ◽  
Author(s):  
Daniel Walgraef
Keyword(s):  
Thin Films ◽  
Laser Irradiation ◽  
Surface Deformation ◽  
Laser Intensity ◽  
Laser Beams ◽  
Experimental Investigations ◽  
Relative Importance ◽  
Periodic Patterns ◽  
One Dimensional ◽  
Deformation Patterns

The coupling between surface deformation and defect motion may be at the origin of deformation patterns in thin films under laser irradiation. We analyze the dynamics of laser-induced vacancy densities and deformation fields and show how it triggers deformational instabilities, in the case of uniform and focused laser irradiation. Pattern selection analysis is performed, through linear, nonlinear, and numerical methods. In irradiation with extended beams, we show that, according to the relative importance of nonlinearities arising from the defect or from the bending dynamics, square, hexagonal or even quasi-periodic patterns are selected. It appears, furthermore, that one-dimensional gratings are always unstable in isotropic systems. In irradiation with focused laser beams, rose deformation patterns, with petal number increasing with laser intensity, naturally arise in this model, in qualitative agreement with experimental observations. These results claim for more systematic and quantitative experimental investigations of deformational pattern formation under laser irradiation.

scholarly journals Application of Laser Irradiation for Restorative Treatments

2016 ◽  
Vol 10 (1) ◽  
pp. 636-642 ◽  
Author(s):  
Amin Davoudi ◽  
Maryam Sanei ◽  
Hamid Badrian
Keyword(s):  
Laser Irradiation ◽  
Dental Practice ◽  
Restorative Dentistry ◽  
Hard Tissue ◽  
Fibrous Matrix ◽  
Pulp Therapy ◽  
Vital Pulp Therapy ◽  
Caries Removal ◽  
Laser Devices

Nowadays, lasers are widely used in many fields of medicine. Also, they can be applied at many branches of dental practice such as diagnosis, preventive procedures, restorative treatments, and endodontic therapies. Procedures like caries removal, re-mineralization, and vital pulp therapy are the most noticeable effects of laser irradiation which has gained much attention among clinicians. With controlled and appropriate wavelength, they can help stimulating dentinogenesis, controlling pulpal hemorrhage, sterilization, healing of collagenic proteins, formation of a fibrous matrix, and inducing hard tissue barrier. Nevertheless, there are many controversies in literatures regarding their effects on the quality of bonded restorations. It hampered a wide application of lasers in some aspects of restorative dentistry and requirements to identify the best way to use this technology. The aim of this mini review is to explain special characteristics of laser therapy and to introduce the possible applications of laser devices for dental purposes.

scholarly journals Two-fluid computations of plasma block dynamics for numerical analyze of rippling effect

2005 ◽  
Vol 23 (4) ◽  
pp. 433-440 ◽  
Author(s):  
S. JABŁONSKI ◽  
H. HORA ◽  
S. GŁOWACZ ◽  
J. BADZIAK ◽  
YU CANG ◽  
...  
Keyword(s):  
Laser Irradiation ◽  
Laser Intensity ◽  
Short Pulse ◽  
Broad Band ◽  
Numerical Computations ◽  
Intensity Range ◽  
Two Fluid

In this paper the results of numerical computations of rippling smoothing basing on the broad-band laser irradiation method for the laser intensity range 1016−1017 W/cm2 and short-pulse (<10 ps) interaction with plasma are described.

scholarly journals Microcolumn development on titanium by multipulse laser irradiation in nitrogen

2003 ◽  
Vol 18 (9) ◽  
pp. 2228-2234 ◽  
Author(s):  
E. György ◽  
A. Pérez del Pino ◽  
P. Serra ◽  
J. L. Morenza
Keyword(s):  
Laser Irradiation ◽  
Crystalline State ◽  
Laser Intensity ◽  
Anatase Phase ◽  
Target Material ◽  
Single Pulse ◽  
Laser Pulses ◽  
Nitrogen Atmosphere ◽  
X Ray ◽  
Melting Threshold

We report the growth of titanium nitride microcolumns under multipulse Nd:yttrium aluminum garnet (λ = 1.064 μm, τ ∼ 300 ns, ν = 30 kHz) laser irradiation of titanium targets in nitrogen atmosphere. The laser intensity value was chosen below the single-pulse melting threshold of titanium. The evolution with the number of laser pulses of the target morphology, crystalline state, and chemical composition at the surface as well as in depth were investigated by scanning electron microscopy, x-ray diffractometry, Raman spectroscopy, and wavelength dispersive x-ray spectroscopy. Under the action of the laser pulses, during progressive surface nitridation, an initial rippled morphology developed, which evolved with further irradiation to TiN microcolumns. In-depth investigations showed a granular zone beneath the surface consisting of rutile and anatase phase TiO2, followed by a compact needlelike layer of titanium until the interface with the unaffected target material.

Single pulse Nd:YAG laser irradiation of titanium: influence of laser intensity on surface morphology

2002 ◽  
Vol 154 (1) ◽  
pp. 63-67 ◽  
Author(s):  
E György ◽  
I.N Mihailescu ◽  
P Serra ◽  
A Pérez del Pino ◽  
J.L Morenza
Keyword(s):  
Surface Morphology ◽  
Laser Irradiation ◽  
Nd:Yag Laser ◽  
Laser Intensity ◽  
Single Pulse

Chronic Laser Exposure Effects on Rabbit Retina

1972 ◽  
Vol 30 ◽  
pp. 54-55
Author(s):  
Burton B. Silver ◽  
Theodore Lawwill
Keyword(s):  
Laser Irradiation ◽  
Laser Light ◽  
Broad Band ◽  
Argon Laser ◽  
Atropine Sulfate ◽  
Ultrastructural Changes ◽  
Laser Exposure ◽  
Rabbit Retina ◽  
Histological Changes ◽  
Threshold Doses

Dutch-belted 1 to 2.5 kg anesthetized rabbits were exposed to either xenon or argon laser light administered in a broad band, designed to cover large areas of the retina. For laser exposure, the pupil was dilated with atropine sulfate 1% and pheny lephrine 10%. All of the laser generated power was within a band centered at 5145.0 Anstroms. Established threshold for 4 hour exposures to laser irradiation are in the order of 25-35 microwatts/cm2. Animals examined for ultrastructural changes received 4 hour threshold doses. These animals exhibited ERG, opthalmascopic, and histological changes consistent with threshold damage.One month following exposure the rabbits were killed with pentobarbitol. The eyes were immediately enucleated and dissected while bathed in 3% phosphate buffered gluteraldehyde.

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