Because of Cadmium selenide quantum dots (CdSe quantum dots) has a tuning energy gap in the visible light range, therefore; it is provided a simple theoretical model for the absorption coefficient of CdSe quantum dots, where the absorption coefficient determines the extent to which the light of a material can penetrate a specific wavelength before it is absorbed. CdSe quantum dots have an energy gap can be controlled through two effects: the temperature and the dot size of them. It is found that; there is an absorption threshold for each directed wavelength, where CdSe quantum dots begin to absorb the visible spectrum at a size of 1.4 nm at room temperature for a directed wavelength 300 nm. It has been observed that; when the wavelength is increasing its absorption threshold is increased. For wavelengths (400, 500, 600) nm, the absorption thresholds for each quantum sizes are (1.8, 2.2. 3.2)nm respectively. On the other hand, a rising of the temperature led to reduces the absorption coefficient value, that at 400 K for all quantum sizes, the absorption coefficient increases >2000cm−1(According to the directed wavelength) than it is at 0 K. CdSe quantum dots can be considered as one of the most promising materials because it has a tuning gap for the visible wavelengthsfor different applications, such as light-emitting diodes in different colors of the visible spectrum. It is found that; there is a good agreement between our theoretical calculations and experimental results.
Tests were performed on Marshall samples and were implemented for permanent deformation and resilient modulus (Mr) under indirect tensile repeated loading (ITRL), with constant stress level. Two types of liquid asphalt (cutback and emulsion) were tried as recycling agents, aged materials that were reclaimed from field (100% RAP), samples were prepared from the aged mixture, and two types of liquid asphalt (cutback and emulsion) with a weight content of 0.5% were utilized to prepare a recycled mixture. A group of twelve samples was prepared for each mixture; six samples were tested directly for ITRL test (three samples at 25˚C and three samples at 40˚C), an average value for ITRL for every three samples was calculated (
... Show MoreIn order to evaluate the effect of seed size, plant growth regulators and some chemical materials on seed vigour and seedling growth of rice (Oryza sativa L.) an experiment was conducted in 2015 at Laboratories of Agriculture and Marshes College, University of Thi-Qar. Factorial experiment in CRD was used with four replications in two factors. The first factor included three seed sizes (4.6-5.1, 5.2-5.7 and 5.8-6.3 mm). The second factor was seeds soaking treatments (KNO3 6 gl-1, CaCl2 20 gl-1, salicylic acid 20 mg l-1, cytokinin 40 mg l-1, gibberllic acid 400 mg l-1, ascorbic acid 40 mg l-1 and seeds soaked in distilled water). The results showed that the largest seed size influenced significantly and gave the higher averages of germinatio
... Show MoreSurge pressure is supplemental pressure because of the movement of the pipes downward and the swab pressure is the pressure reduction as a result of the drill string's upward movement. Bottom hole pressure is reduced because of swabbing influence. An Investigation showed that the surge pressure has great importance for the circulation loss problem produced by unstable processes in the management pressure drilling (MPD) actions. Through Trip Margin there is an increase in the hydrostatic pressure of mud that compensates for the reduction of bottom pressure due to stop pumping and/or swabbing effect while pulling the pipe out of the hole. This overview shows suggested mathematical/numerical models for simulating surge pressure problems ins
... Show MoreThis research aims to study the influence of organizational power on the achievement of entrepreneurship for business organizations. It is an analytical study of the views of a sample of managers in the Iraqi Ministry of Education. The research highlights the contribution that can be made from the knowledge of the theory of business organizations in achieving organizational success. The organizational power of the organization contributes to achieving entrepreneurship in the business environment and achieving a competitive position in the work environment. The research dealt with two variables: the first is the independent variable, the organizational power in its dimensions (Expend Power, Structural Power, Prestige Power). And t
... Show MoreThe contribution rate of tax revenues in the federal budget is very small compared to the rate of contribution of oil revenues and this leads to negative repercussions on the Iraqi economy and the budget becomes a prisoner of high and low oil prices, and this is a problem that needs to be studied to know the extent of the impact of economic and political decisions on the size of tax revenue and The research goal is determined in studying the effect of amending the Unified Law No (26) of 2019 on the size of annual tax revenues . &
... Show MoreThis research studies the rheological properties ( plastic viscosity, yield point and apparent viscosity) of Non-Newtonian fluids under the effect of temperature using different chemical additives, such as (xanthan gum (xc-polymer), carboxyl methyl cellulose ( High and low viscosity ) ,polyacrylamide, polyvinyl alcohol, starch, Quebracho and Chrome Lignosulfonate). The samples were prepared by mixing 22.5g of bentonite with 350 ml of water and adding the additives in four different concentrations (3, 6, 9, 13) g by using Hamilton Beach mixer. The rheological properties of prepared samples were measured by using Fan viscometer model 8-speeds. All the samples were subjected to Bingham plastic model. The temperature range studi
... Show MoreNowadays, most of the on-chip plasmonic single-photon sources emit an unpolarized stream of single photons that demand a subsequent polarizer stage in a practical quantum cryptography system. In this paper, we numerically demonstrated the coupling of the light emitted from a quantum emitter (QE) at 700 nm wavelength to the propagation mode supported by an on-chip hybrid plasmonic waveguide (HPW) polarization rotator. Our results proved that the light emitted is linearly polarized at 0º, 45º/−45º, and 90º with propagation lengths of 5 μm, 3.3 μm, and 3.9 μm, respectively. Moreover, high power-conversion efficiency was obtained from an applied transverse magnetic (TM) mode (0º-polarization) to a transverse electric (TE) (90º-polari
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