A single-crystalline semi-polar gallium nitride (11-22) was grown on m-plane (10-10) sapphire substrate by metal organic chemical vapor deposition. Three-step approach was introduced to investigate the grain size evolution for semi-polar (11-22) GaN. Such approach was achieved due to the optimized gallium to ammonia ratio and temperature variations, which led to high quality (11-22) oriented gallium nitride epilayers. The full width at half maximum values along (-1-123) and (1-100) planes for the overgrowth temperature of 1080°C were found to be as low as 0.37° and 0.49°, respectively. This was an indication of the enhanced coalescence and reduction in root mean square roughness as seen by atomic force microscopy. Surface analysis via atomic force microscopy indicated the orientation towards semi-polar plane. Field emission scanning electron microscopy analysis further indicates that higher temperature of 1080°C during the deposition of the overgrowth promoted closely packed surface coalescence. Room temperature Raman revealed that the overgrowth temperature of 1080°C portrayed compressive strain free as compared to other overgrowth temperature. Based on these results, the promising overgrowth temperature of 1080°C can be further utilized in future work for optoelectronics devices.
The effect of cognitive trips via the Internet (web quest) accompanying practical lessons in learning some basic handball skills for female students
The present research aims to study the effect of friction stir welding (FSW) parameters on temperature distribution and tensile strength of aluminum 6061-T6. Rotational and traverse speeds used were (500,1000,1400 rpm) and (14,40,112 mm/min) respectively. Results of mechanical tests showed that using 500rpm and 14mm/min speed give the best strength. A three- dimensional fully coupled thermal-stress finite element model via ANSYS software has been developed. The Rate dependent Johnson-Cook relation was utilized for elasto-plastic work deformations. Heat-transfer is formulated using a moving heat source, and later used the transient temperature outputs from the thermal analysis to determine equivalent stresses in the welde
... Show MoreIn this study, several models of the rocket fins were made of hyper composite materials (with two or more reinforced materials) with different volume fractions of components used to produce isotropic composite plate structures. The reinforcement of polyester resin material was done in two ways, with fibre reinforcement and powder reinforcement. The types of fibresthat used were chopped glass fibre and chopped carbon fibre, and the type of powder used was carbon powder. A concentrated load was applied to the models in the form of a cantilever plate. The effect of adding carbon powder on the stiffness to weight ratio and the effect of temperature on this stiffness to weight ratio were studied and discussed. It was observed that hybridization
... Show MoreA new, accurate, precise and economic two spectrophotometric methods for determination of Paracetamol (Par), Ibuprofen (Ibu), and Caffeine (Caf) were suggested. Those methods were the first and second ratio derivative spectrum using a double devisor. Par, Ibu, and Caf showed many useful peaks for their quantified determination. The validity of all analysis modes for determination of the three compounds, peak to baseline, peak area and peak to peak were according to ICH. The linearity of two methods was between 5 µg/ml as a lower concentration and 50 µg/ml as the highest concentration for three compounds. Recovery percentage was around 100% and relative standard deviation was less than 2.6%. The methods were applied successfully in the
... Show MoreThis work presents a novel technique for the detection of oil aging in electrical transformers using a single mode optical fiber sensor based on surface plasmon resonance (SPR). The aging of insulating oil is a critical issue in the maintenance and performance of electrical transformers, as it can lead to reduce insulation properties, increase risk of electrical breakdown, and decrease operational lifespan. Many parameters are calculated in this study in order to examine the efficiency of this sensor like sensitivity (S), signal to noise ratio (SNR), resolution (refractive index unit) and figure of merit (FOM) and the values are for figure of merit is 11.05, the signal to noise ratio is 20.3, the sensitivity is 6.63, and the resolution is 3
... Show MoreThe aim of this study was to increasing natural carotenoides production by a locally isolate Rodotorula mucilagenosa M. by determination of the optimal conditions for growth and production of this agents, for encouragest to use it in food application permute artificial pigments which harmfull for consumer health and envieronmental. The optimal condition of carotenoides production from Rhodotorula mucilaginosa M were studied. The results shows the best carbon and nitrogen source were glucose and yeast extract. The carotenoids a mount production was 47430 microgram ̸ litter and 47460 microgram ̸ litter, respectively, and the optimum temperature was 30°C, PH 6, that the carotenoides a mount was 47470 microgram ̸ litter and 47670 microgr
... Show MoreThis study aims to identify the Israeli policies towards Palestinian refugees during the period 1999-2010 which had seen several Israeli governments, whether left or right, The researcher found that there is continuity in decision-making and legislation in Israeli governments, regardless of political or ideological orientation towards refugees and the Palestinians during the study, which focused on two main axis, The first: refugee issue in the permanent negotiations where the researcher found that the Israeli position is fixed of the non-return of Palestinian refugees, and Increased the power of the Israeli position by U.S. The seconds axis: deals with Israeli legislation and the views taken by Israel which prevent the right of return f
... Show MoreMeasuring university teachers attitudes towards the security man Summary This research aims to study the measurement of university teachers attitudes towards the security man, and represented the research sample (196) of teachers, including 124 males and 72 females from different faculties of Salah al-Din - Erbil University. The researchers adopted on a scale (Al-Tarawneh 2008), as amended, and its development, the scale consists of four areas and (28) paragraph covers paragraphs measure the beliefs and feelings of the individual towards the security man as the theme of direction. The research sample answered all the paragraphs of the scale grade five similar styles (Likert) (strongly OK, OK, neutral, non-OK, Strongly Disagree). The rese
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