Experimental and numerical studies have been conducted for the effect of injected air bubbles on the heat transfer coefficient through the water flow in a vertical pipe under the influence of uniform heat flux. The investigated parameters were water flow rate of (10, 14 and 18) lit/min, air flow rate of (1.5, 3 and 4) lit/min for subjected heat fluxes of (27264, 36316 and 45398) W/m2. The energy, momentum and continuity equations were solved numerically to describe the motion of flow. Turbulence models k-ε was implemented. The mathematical model is using a CFD code Fluent (Ansys15). The water was used as continuous phase while the air was represented as dispersed. phase. The experimental work includes design, build and instrument a test rig for that purpose. A
circular vertical copper pipe test section of (length=0.7m, diameter= 0.05m, thickness= 1.5mm) is . designed and constructed, heated by an electrical heater fixed on its outer surface. Water . temperature at inlet is kept constant at (32°C). Water inlet and outlet temperatures, as well as radial temperature distribution within the pipe at seven sections along it between pipe surface and its center are measured. The results revealed that the secondary flow created by air bubbles have
significant effects on heat transfer enhancement and temperature profile. It is observed, that averaged Nusselt number enhancement for low heat flux of 27264 W/m2 and 4 lit/min air bubbles was 33.3 % and 23% in numerical and experimental, respectively.
In this work we fabrication holographic optical element diffraction grating thickness 40?m and mirror90?m by using dichromated gelatin,to perform that we have to use the Nd-yaG laser doubling frequency of wavelenght (532)nm and its powers of (80)mWatt.we have studyed the thickness and concentration dichromat effect in mirror reflaction ,effect of angle of reconstruction beam in band width and diffraction efficiency ,study effect gelatin hardener of the diffraction efficiency.
This paper proposes and studies an ecotoxicant system with Lotka-Volterra functional response for predation including prey protective region. The equilibrium points and the stability of this model have been investigated analytically both locally and globally. Finally, numerical simulations and graphical representations have been utilized to support our analytical findings
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Bending effects on the transmission of optical signal are investigated on a single mode
optical fiber (SMOF) of 10 m length, core radius of 5 μm and optical refractive index difference
0.003. The bending radii (R) were between 0.08 and 0.0015 m. A great decrease in the amplitude is
shown for radii below 0.01 m. Sudden break down occurs for radii less than 0.0015 m. Birefringence
(B) is difficult to measure for long fibers. Meanwhile, B was found by comparing with calibrated
fiber of the same properties but of length of 0.075 m. The results show an increase in propagation
constant (Δβ) and the decrease in beat length (Lb), and show that bending decreases the critical radius
of curvature (Rc) related to B. The chang
An experimental work has been conducted on wall attachment fluidics amplifiers, one of them to study the effect of output pressure or load on the amplifier performance. The output load has been simulated as a piston connected to the device output and the piston can be loaded accordingly. The results shows that the output volume flow rate increases as the supply pressure increases under different load and the output pressure remains constant as the supply pressure increases under constant load.
Marriage is a characteristic of the human race, as it is one of the oldest organization, asoldas human beign marrige is a legitimale relationsbip between male and female in the name of Allah "o mankind !Be dutiful to your lord, Who created you from a single person (Adam), and from him (Adam) He created his Wife (Eve), and from them both He created mang men and women
Marriage is a requirement of human life to ensure tle continuity and survival of the human species and established it in a legal, social and legitimate frame,according to certain criteria and conditions so that the individual earns psychological and social comfort in the name of Allah and Allah has made for you Azwaj ( mates or wives), sons and grand sons, and has bestowed
The flow emission rate of hard photons from lowest order the QCD processes for quark-anti quark annihilation processes in plasma media at high temperatures (175, 200, 225, 250 and 275 MeV) have been study. In these framework photons, the flow photons emission is calculate according to quark-antiquark annihilation using the quantum chromodynamic theory and solves the ultrarelativistic equation with MATLAP program. Due to the results, we show increases flow photons rate with increases strength coupling and increases with increases temperature of media, it indicate that logarithmically divergent thermal effect on photons product. The critical temperature (Tc=155 to 195 MeV) effect on the quarks confined in hadronic matter phase, it is importan
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This work is concerned with a two stages four beds adsorption chiller utilizing activated carbon-methanol adsorption pair that operates on six separated processes. The four beds that act as thermal compressors are powered by a low grade thermal energy in the form of hot water at a temperature range of 65 to 83 °C. As well as, the water pumps and control cycle consume insignificant electrical power. This adsorption chiller consists of three water cycles. The first water cycle is the driven hot water cycle. The second cycle is the cold water cycle to cool the carbon, which adsorbs the methanol. Finally, the chilled water cycle that is used to overcome the building load. The theoretical results showed that average cycle cooling power
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New microphotometer was constructed in our Laboratory Which deals with the determination of Molybdenum (VI) through its Catalysis effect on Hydrogen peroxide and potasum iodide Reaction in acid medium H2SO4 0.01 mM. Linearity of 97.3% for the range 5- 100 ppm. The repeatability of result was better than 0.8 % 0.5 ppm was obtanined as L.U. (The method applied for the determination of Molybdenum (VI) in medicinal Sample (centrum). The determination was compared well with the developed method the conventional method.