In this work, a pulsed Nd:YAG laser(out put energy=5J and pulse
duration=300μsec) was used to perform drilling in samples of lead, stainless steel
304, brass, copper and aluminum. Laser irradiation was carried out in both air and
in a suitable chamber of controlled pressure inside. The effect of pressure inside the
chamber on the drilling process was investigated. Then, the chamber was filled with
argon gas to investigate its effect on drilling process where an enhancement in
drilling depth was observed compared to that in case of irradiation in air and
chamber of air pressure. As well, the effect of focus position on the process was
studied with the pressure varying inside the chamber in order to construct a
mathematical model describing such process
In this work; Silicon dioxide (SiO2) were fabricated by pulsed
laser ablation (PLA). The electron temperature was calculated by
reading the data of I-V curve of Langmuir probe which was
employed as a diagnostic technique for measuring plasma properties.
Pulsed Nd:YA Glaser was used for measuring the electron
temperature of SiO2 plasma plume under vacuum environment with
varying both pressure and axial distance from the target surface. The
electron temperature has been measured experimentally and the
effects of each of pressure and Langmuir probe distance from the
target were studied. An inverse relationship between electron
temperature and both pressure and axial distance was observed.
Aluminum doped zinc oxide nanoparticles (AZO) with different doping concentrations were prepared by Nd-YAG laser ablation of target in deionized water. The characterization of these nanoparticles was performed using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and photoluminance spectroscopy (PL). FTIR spectra confirmed the formation of vibrational bonds for ZnO NPs and AZO NPs. SEM images illustrated that the size and shape of the NPs changed with changing the number of laser pulses. Photoluminescence peaks exhibited two emission peaks, one at the UV region and the second in the visible region, which were modified as the number of laser pulses and doping concentration were ch
... Show MoreLight has already becomes a popular means of communication, and the high-bandwidth data into free space without the use of wires. A great idea took us to design a new system for transmitting sound through free space at (650, 532) nm wavelengths using reflective mirrors under different atmospheric conditions. The study showed us the effect of various weather factors (temperature, wind speed and humidity) on these wavelengths for different distances. As well as studying the attenuation caused by long-distance laser and beam divergence, A reflective dish was used to focus the spot of the laser beam on the photocell. Results were discussed under the effect of these factors and the attenuation resulting from the beam divergence. Thus, the sys
... Show MoreLaser ablation of a silver target immersed in distilled water using Nd:YAG laser with a fundamental wavelength of 1064nm was carried out to fabricate silver nanoparticles (Ag NPs) with different laser energy in the presence and absence of magnetic field. UV-Visible spectrum showed that the nanoparticles are almost spherical in shape. The number of Ag NPs increased by increasing laser energy while their particle size was reduced by increasing laser energy without magnetic field. In the presence of magnetic field, the size of Ag NPs increased slightly by increasing laser energy. According to AFM results, the presence of magnetic field did not affect the average diameter of Ag NPs. The presence of a magn
... Show MoreIn an attempt to disposal from nuclear waste which threats our health and environments. Therefore we have to find appropriate method to immobilize nuclear waste. So, in this research the nuclear waste (Strontium hydroxide) was immobilized by Carbon nanotubes (CNTs). The Nd-YAG laser with wave length 1064 nm, energy 750 mJ and 100 pulses used to prepare CNTs. After that adding Sr(HO)2 powder to the CNTs colloidal in calculated rate to get homogenous mixing of CNTs-Sr(OH)2. The Sr(HO)2 absorbs carbon dioxide from the air to form strontium carbonate so, the new solution is CNTs-SrCO3. To dry solution putting three drops from the new solution on the glass slides. To investigate the radi
... Show MoreIn this paper, the productions of gallium oxide (Ga2O3) nanoparticles were achieved via using the Nd: YAG laser deposition method with a fundamental wavelength (1064 nm). These nanoparticles were characterized by using different methods such as X-ray diffractometer (XRD), atomic force microscopy (AFM) and Ultraviolet–visible (UV–vis) spectroscopy. To examine the effects of laser energy on the properties of nanoparticles, the experimental results and theoretical considerations were prepared by the effective method of pulse laser deposition. The synthesis of Ga2O3NPs) was achieved with different ranges of energies (500 to 900 mJ). Average crystallite sizes of the synthesized nanopar
... Show MoreUnder cyclic loading, aluminum alloys exhibit less fatigue life than steel alloys of similar strength and this is considered as Achilles's heel of such alloys. A nanosecond fiber laser was used to apply high speed laser shock peening process on thin aluminum plates in order to enhance the fatigue life by introducing compressive residual stresses. The effect of three working parameters namely the pulse repetition rate (PRR), spot size (ω) and scanning speed (v) on limiting the fatigue failure was investigated. The optimum results, represented by the longer fatigue life, were at PRR of 22.5 kHz, ω of 0.04 mm and at both v's of 200 and 500 mm/sec. The research yielded significant results represented by a maximum percentage increase in the fa
... Show MoreFluorescent Carbon Quantum Dots (CQDS) are a new kind of carbon nanoparticles that have appeared recently and have collected much interest as potential competitors to conventional semiconductor quantum dots (QDs). In addition to their comparable fluorescent properties, CQDs have the desired specifications of environmental friendliness, low toxicity, simple synthetic routes, low cost and surface passivation The functionalization of CQDS allow the control of their physicochemical properties. The main aim of this kind of researches is to account the variables that cannot be measured directly from practical experiments. Therefore, the work here is focused on the account energy gap of bulk (Eg bulk) by theoretically method (simulation) after
... Show MoreYtterbium-doped (Y2O3), (Sc2O3) and (YAG) crystals are very important for high-power thindisk lasers. These lasers have shown their ability to operate quasi-three-level materials with high
efficiency as well as high thermal conductivity ratio for crystalline hosts. All these reasons have
required studying this type of laser. In the present work, the analytical solution was found for the
equation of laser output power, pumping threshold power, and efficiency of a quasi-three-level
thin disk laser. The numerical solution of these equations was also found through the Matlab
program at the fundamental transverse mode, at a temperature of 299K0
and with high pumping
capabilities in order to know the e
The size and the concentration of the gold nanoparticles (GNPs)
synthesized in double distilled deionized water (DDDW) have been
found to be affected by the laser energy and the number of pulses.
The absorption spectra of the nanoparticles DDDW, and the
surface plasmon resonance (SPR) peaks were measured, and found to
be located between (509 and 524)nm using the UV- Vis
spectrophotometer. SPR calculations, images of transmission
electron microscope, and dynamic light scattering (DLS) method
were used to determine the size of GNPs, which found to be ranged
between (3.5 and 27) nm. The concentrations of GNPs in colloidal
solutions found to be ranged between (37 and 142) ppm, and
measured by atomic absorptio