Simulation of free convection heat transfer in a square enclosure induced by heated thin plate is represented numerically. All the enclosure walls have constant temperature lower than the plate’s temperature. The flow is assumed to be two-dimensional. The discretized equations were solved stream function, vorticity, and energy equations by finite difference method using explicit technique and Successive Over- Relaxation method. The study was performed for different values of Rayleigh number ranging from 103 to 105 for different angle position of heated thin plate(0°, 45°, 90°). Air was chosen as a working fluid (Pr = 0.71). Aspect ratio of center of plate to the parallel left wall A2 take a constant and is equal to 0.5. The effect of the angle position of the heated thin plate on heat transfer and flow were addressed. With the increase of Rayleigh number heat transfer rate increased in both vertical and horizontal position of the plate. For the vertical situation (γ=90°) of thin plate, heat transfer becomes more enhanced than for the horizontal situation (γ=0°) and the inclined situation (γ=45°) especially when the value of aspect ratio A1 is equal to 0.25.
The aim of this study was to know ( the impact of education differentiated strategy to modify the alternative developments of geographical concepts when students first grade average) .
To achieve the goal of this study , researcher relied on the experimental design of a partial set , the design is ( the experimental group with a control group of post-test ).
&nbs
... Show More
Facing industrial companies many pressures and challenges due to rapid changes in the business environment of contemporary, which requires them to do their performance look more inclusive rather than limiting performance evaluation on the financial perspective in spite of its importance, prompting companies to rethink their reality competitive through the adoption of methodologies and new philosophies to manage competitiveness of total quality management, and re-engineering of production processes, and knowledge management,... etc., as This study framework cognitive and practical "to evaluate the performance of a company Diyala General Electric Industries and how to rehabilitate
(1)
An aromatic ester containing two azo groups namely p-nitro phenyl azo-β-naphthyl-(4'-azobenzoic acid)-4-benzoate was synthesized by esterfiaction of 4,4'-azo dibenzoic acid with p-nitro phenyl azo-β-naphthol. Synthesized ester was characterized by CHN-Elemental analysis, FTIR, 1H NMR and 13C NMR. A modified PVA polymer was obtained by grafting 10 g of PVA-polymer via partial esterification with (2, 3, 4 g) p-nitro phenyl azo-1-naphthyl-4-azobenzoic acid)-4-azo benzoate. Grafting PVA-polymer behaviours was studied, by physical measurements (solubility, swelling), thermal properties (DSC) and tensile.
(7)
(8)
(10)
(7)
A new ligand 3-hydroxy-2-(3-(4-nitrobenzoyl) thiouriedo) propanoic acid (NTP) where synthesized by reaction of 4-nitro benzoyl isothiocyanate with serine amino acid. The ligand was characterized by FT-IR, NMR spectra and the elemental analysis. The transition metal complexes of this ligand where synthesize and characterized by UV-Visible spectra, FT-IR, magnetic suscpility, conductively measurement, The general formula [M (NTP) 2] where M+2= (Mn, Co, Ni, Cu, Zn, Cd, Hg,), the form of molecular for these complexes as tetrahedral except Cu has square planer.
In this research the hard chromium electroplating process, which is one of the common methods of overlay coating was used, by using chromium acid as source of chromium and sulphuric acid as catalyst since the ratio between chromic acid and sulphuric acid is (100 : 1) consequently. Plating process was made by applying current of density (40 Amp / dm2) and the range of solution temperature was (50 – 55oC) with different time periods (1-5 hr). A low carbon steel type (Ck15) was used as substrate for hard chromium electroplating. Solid carburization was carried out for hard chromium plating specimen at temperature (925oC) with time duration (2 hr) to be followed with quenching and tempering
... Show More
(1)
(1)
The effect of thermal treatment on optical constants of pure PMMA and with addition (15 and 35) ml of coumarin at different temperatures (100, 110 and 120) C0 for 1 hour were investigated. Cast method used to prepares films of pure PMMA and PMMA with (15 and 35) of coumarin. UV/VIS spectrometer technique used to measure the absorption spectra for these films. The optical constant (absorption spectra and absorption coefficient) don’t changes after applied temperatures in pure PMMA film but the optical constant (absorption spectra and absorption coefficient) in PMMA with (15 and 35) ml of coumarin increased with applied temperatures. The optical energy gap of pure PMMA and PMMA with (15 and 35) ml of coumarin sl
... Show More
(8)
(5)
(13)
(12)