Semiconductor laser is used in processing many issues related to the scientific, military, medical, industrial and agricultural fields due to its unique properties such as coherence and high strength where GaN-based components are the most efficient in this field. Current technological developments mention to the strong connection of GaN with sustainable electronic and optoelectronic devices which have high-efficiency. The threshold current density of Al0.1Ga0.9N/GaN triple quantum well laser structure was investigated to determine best values of the parameters affecting the threshold current density that are well width, average thickness of active region, cavity length, reflectivity of cavity mirrors and optical confinement factor. The optimum value of the threshold current density is 2670 A/cm2 was obtained when the well width (w= 2.5 nm), reflectivity of cavity mirrors (R1=0.75, R2=0.9), cavity length (L=2mm), average thickness of active region (d= 11.5 nm), and optical confinement factor ( Γ= 0.034) at room temperature.
Background: The aims of this study were to evaluate the effect of implant site preparation in low-density bone using osseodensification method in terms of implant stability changes during the osseous healing period and peri-implant bone density using CBCT. Material and methods: This prospective observational clinical study included 24 patients who received 46 dental implants that were installed in low-density bone using the osseodensification method. CBCT was used to measure the bone density pre- and postoperatively and implant stability was measured using Periotest® immediately after implant insertion and then after 6 weeks and 12 weeks postoperatively. The data were analyzed using paired t-test and the probability value <0.05 was conside
... Show MoreThe fingerprints are the more utilized biometric feature for person identification and verification. The fingerprint is easy to understand compare to another existing biometric type such as voice, face. It is capable to create a very high recognition rate for human recognition. In this paper the geometric rotation transform is applied on fingerprint image to obtain a new level of features to represent the finger characteristics and to use for personal identification; the local features are used for their ability to reflect the statistical behavior of fingerprint variation at fingerprint image. The proposed fingerprint system contains three main stages, they are: (i) preprocessing, (ii) feature extraction, and (iii) matching. The preprocessi
... Show MoreIn this work, we have used the QCD dynamic scenario of the quark gluon interaction to investigate and study photon emission theoretically based on quantum theory. The QCD theory is implemented by deriving the photon emission rate equation of the state of ideal QGP at a chemical potential. The photon rate of the quark-gluon interaction has to be calculated for the anti up-gluon interaction in the g → γ system at the temperature of system with critical temperature ( 132.38, , and 198.57) MeV and photon energy ( GeV. We investigated a significant effect of critical temperature, strength coupling, and photon energy on the photon rate contribution. Here, the increased photon emission rate and decreased streng
... Show MoreThe poor hole cleaning efficiency could causes many problems such as high torque, drag, poor hydraulics and pipe stuck. These inherent problems result in an avoidable high operation cost which this study tried to address. In this study, the effect of cutting density on hole cleaning efficiency in deviated and horizontal wells was investigated. Experiments were conducted using 40 feet (12 m) long of flow loop made from iron and PVC. However, the test section was made from PVC with (5.1m) long and (4” ID) for outer pipe and (2” OD) inner pipe. The cutting transport ratio (CTR) was determined from weight measurements for each test. Cutting Transport Ratio has been investigated for effects of the following parameters; flow rate, cu
... Show MoreCarbon nanoparticles (CNPs) formed by one-step laser ablation in deionized water were carefully studied. Scanning electron microscopy, atomic force microscopy, Raman spectroscopy, and UV–V spectroscopy were used to obtain morphological, chemical, and optical properties of CNPs. SEM outcomes established that the synthesized nanoparticles are semi-spherical with a wide particle size distribution. Raman investigation showed two typical and expected peaks ~ (1300 - 2700) cm−1, which are confirming to transverse and longitudinal modes of the carbon structure. The absorption spectra proved that the intensity of spectra increases as particle size and concentration increase.
In this work; copper oxide films (CuO) were fabricated by PLD. The films were analyzed by UV-VIS absorption spectra and their thickness by using profilometer. Pulsed Nd:YAG laser was used for prepared CuO thin films under O2 gas environment with varying both pulse energy and annealing temperature. The optical properties of as-grown film such as optical transmittance spectrum, refractive index and energy gap has been measured experimentally and the effects of laser pulse energy and annealing temperature on it were studied. An inverse relationship between energy gap and both annealing temperature and pulse energy was observed.
The purpose of this research is to investigate the impact of corrosive environment (corrosive ferric chloride of 1, 2, 5, 6% wt. at room temperature), immersion period of (48, 72, 96, 120, 144 hours), and surface roughness on pitting corrosion characteristics and use the data to build an artificial neural network and test its ability to predict the depth and intensity of pitting corrosion in a variety of conditions. Pit density and depth were calculated using a pitting corrosion test on carbon steel (C-4130). Pitting corrosion experimental tests were used to develop artificial neural network (ANN) models for predicting pitting corrosion characteristics. It was found that artificial neural network models were shown to be
... Show MorePM3 semiempirical method and Density Functional Theory (DFT) calculations of the type (B3LYP) and a Gaussian basis set (6-311G) were carried out for fullerene C60 molecule with its construction units (5radialene, 1,2,3-trimethylene indan, and corannulene), to evaluate the geometrical structure (bond lengths, symmetry, and energetic such as heat of formation ΔH0f, total energy Etot., dipole moment μ, EHOMO (highest occupied molecular orbital energy), ELUMO (lowest unoccupied molecular orbital energy), energy gap ΔEHOMO-LUMO), the distribution of electron density and vibration frequencies, all at their equilibrium geometries. Assignment of the vibrations modes was done according to the movement of the atoms as a result of DFT calculatio
... Show MorePM3 semiempirical method and Density Functional Theory (DFT) calculations of the type (B3LYP) and a Gaussian basis set (6-311G) were carried out for fullerene C60 molecule with its construction units (5radialene, 1,2,3-trimethylene indan, and corannulene), to evaluate the geometrical structure (bond lengths, symmetry, and energetic such as heat of formation ΔH0f, total energy Etot., dipole moment μ, EHOMO (highest occupied molecular orbital energy), ELUMO (lowest unoccupied molecular orbital energy), energy gap ΔEHOMO-LUMO), the distribution of electron density and vibration frequencies, all at their equilibrium geometries. Assignment of the vibrations modes was done according to the movement of the atoms as a result of DFT calculatio
... Show MoreBeta-irradiation effects on the microstructure of LDPE samples have been investigated
using Positron Annihilation Lifetime Technique (PALT). These effects on the orthopositronium
(o-Ps) Lifetime t3, the free positron annihilation lifetime 2 t , the free-volume
hole size (Vh) and the free volume fraction (fh) were measured as functions of Beta
irradiation - dose up to a total dose of 30.28 kGy.
The results show that the values of t3, Vh and fh increase gradually with increasing Beta
dose up to a total dose of 1.289 kGy, and reach a maximum increment of 17.4%, 32.8% and
5.86%, respectively, while t2 reachs maximum increment of 211.9% at a total dose of 1.59
kGy. Above these doses, the values show nonlinear changes u