The aim of this paper is to investigate the effects of Nd:YAG laser shock processing (LSP) on micro-hardness and surface roughness of 86400Cu-Zn alloy. X-ray fluorescence technique was used to analyze the chemical composition of this alloy. LSP treatment was performed with a Q-switched Nd: YAG laser with a wavelength of 1064 nm. The results show that laser shock processing can significantly increase. The micro-hardness and surface roughness of the LSP-treated sample. Vickers diamond indenter was used to measure the micro-hardness of all samples with different laser pulse energy and the different number of laser pulses. It is found that the metal hardness can be significantly increased to more than 80% by increasing the laser energy and the number of laser pulse irradiated per unit area. The relationship between laser pulse energy and the value of surface roughness is a proportionality due to the increase in ablation processes which are associated with LSP at sample surface caused by the increasing of laser pulse energy.
Background: Surface treatment of machined dental zirconia for enhancement of the adhesion to resin cement, using Er,Cr:YSGG Laser. Materials and Methods: Total number of 42 zirconia disc specimens (9 mm diameter, and 2 mm height) was sintered according to the manufacturer instruction. They are divided into six groups, each group of seven samples. Laser groups (Experiment parameters) were depend on laser total irradiation time, pulse duration, and power. Group (A): 20 sec., 60 µs pulse duration. Group (B): 30 sec., 60 µs pulse duration. Group (C): 40 sec., 60 µs pulse duration. Group (D): 20 sec., 700 µs pulse duration. Group (E): 30 sec., 700 µs pulse duration, with different powers used (1, 1
... Show MoreThe main purpose of this work is the construction of an optical parametric amplifier (OPA) to generate a 629 nm pulsed laser. KTP nonlinear crystals were used for both parametric oscillation and amplification. A singly resonant parametric oscillator (OPO) is constructed to generate a signal of 1.54 μm and idler of 3.4 μm when the OPO system is pumped by 1.064 μm Q – switched Nd: YAG laser. The signal was then mixed with the pumping beam in OPA system to form the wanted wavelength. The obtained optical conversion efficiency was 60%.
This is prospective study began in Jan. 2003 and concluded in April 2004, was undertaken to examine the benefits of 810 nm diode laser in treatment of four patient with bilateral vocal cord paralysis also to compare the results with conventional treatment Material and methods: 810 nm diode laser 15 watts was used in these cases under general anesthesia, and induction of anesthetic drug done through tracheostomy tube in all patients. All patients were decanulated “Tracheostomy tube removed”, the voice of all preserved within normal. Laser surgery in this case has more benefit and advantage than conventional methods even if the patient need more than on session of laser operation because of high success rate, less complication and easy
... Show MoreThe present study was conducted on 20 patients suffering from different types of lesion like
pyogenic granuloma, peripheral giant cell granuloma, mucoceles, pregnancy tumour, Fordyce's granules
and irritating fibroma.The cases were selected from outpatient clinic of the Al Kydhemya Teaching
Hospital. Patients were treated by diode laser (810±20 nm) at the affected areas of the oral cavity with
continuous contact focused mode until excision of the lesion with coagulation of the oozing area after
excision. Patients were followed up after 2 days, 7 days and 2 weeks to assess healing process and any
post operative complication. Some of undiagnosed lesion sent for histopathological examination. No
serious complications w
Femtosecond laser pulse propagation in monomode optical fibers is demonstrated and investigated numerically (by simulations) and experimentally in this paper. A passively mode locked Nd:glass laser giving a pulse duration of about 200 fsec at 1053 nm wavelength and 120 mW average optical power with 100 MHz repetition rate is used in the experimental work. Numerical simulations are done by solving the nonlinear Schrödinger equation with the aid of Matlab program. The results show that self phase modulation (SPM) leads to compression of the spectral width from 5 nm to 2.1 nm after propagation of different optical powers (34, 43, 86 and 120 mW) in fibers of different length (5, 15, 35 m). The varying optical powers produced a varying
... Show MoreA thin film of SnSe were deposited by thermal evaporation technique on 400 ±20 nm thick glass substrates of these films were annealed at different temperatures (100,150,200 ⁰C), The effect of annealing on the characteristics of the nano crystalline SnSe thin films was investigated using XRD, UV-VIS absorption spectroscopy, Atomic Force Microscope (AFM), and Hall effect measurements. The results of X-ray displayed that all the thin films have polycrystalline and orthorhombic structure in nature, while UV-VIS study showed that the SnSe has direct band gap of nano crystalline and it is changed from 60.12 to 94.70 nm with increasing annealing temperature. Hall effect measurements showed that all the films have a positive Hall coeffic
... Show MoreAcrylic polymer/cement nanocomposites in dark and light colors have been developed for coating floors and swimming pools. This work aims to emphasize the effect of cement filling on the mechanical parameters, thermal stability, and wettability of acrylic polymer. The preparation was carried out using the casting method from acrylic polymer coating solution, which was added to cement nanoparticles (65 nm) with weight concentrations of (0, 1, 2, 4, and 8 wt%) to achieve high-quality specifications and good adhesion. Maximum impact strength and Hardness shore A were observed at cement ratios of 2 wt% and 4 wt%, respectively. Changing the filling ratio has a significant effect on the strain of the nanocomposites. The contact angle was i
... Show MoreAbstract
This study came to clarify the redemption in terms of being a method and a subject of knowledge that has its causes, controls, etiquette and scientific implications for Muslim scholars.
The science of redemption has a historical extension, starting from the era of the Companions - may God be pleased with them - and through the stages of codification and classification of works in an effort to document it and diversify its methods at the inductive, analytical, critical and argumentative levels, and to determine its causes and from the completion of the research conclude it with evidence of its scientific effects because it is a science that enriched the Islamic library in general, and hadith in particular.
The aim of this work is synthesis of _Eoly (Vinyl-4-AminoBenzoate) (PVAB) from reaction of _Eoly Vinyl Alkohol PVA with 4-aminobenzoyl chloride in alkaline media. We also prepare the metal complexes of poly (vinyl- 4-aminobenzoate) and antimicrobial properties were evaluated by dilute method against five pathogenic bacteria (Escherichia coli, Shigella dysentery, Klebsiella pneumonae, Staphylococcus aureus, Staphylococcus Albus) and two fungal (Aspergillus Niger, Yeast). All polymer metal complexes showed different activities against the various microbial isolates. The polymer metal complexes showed higher activity than the free polymer.