been taken at room temperature down to liquid nitrogen temperature (77K). Polar and nonpolar solvents have been used to study the solvent effect on the absorption and fluorescence spectra of solute molecules. Some of the spectroscopic parameters have been determined as functions of solvent polarity and temperature. The results indicate that the band width FWHM increases with increasing the solvent polarity and temperature, while the peak emission cross section decreases with increasing of solvent polarity and decreases with increasing the temperatures. Clear vibrational structure spectra of benzoanthracene molecules have been observed in Nonane and Hexane solvents at 77K.
The main objective of present work is to describe the feasibility of friction stir welding (FSW) for
joining of low carbon steel with dimensions (3 mm X 80 mm X 150 mm). A matrix (3×3) of welding
parameters (welding speed and tool rotational speed) was used to see influence of each parameter on
properties of welded joint .Series of (FSW) experiments were conducted using CNC milling machine
utilizing the wide range of rotational speed and transverse speed of the machine. Effect of welding
parameters on mechanical properties of weld joints were investigated using different mechanical tests
including (tensile and microhardness tests ). Micro structural change during (FSW) process was
studied and different welding zones
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 determination of critical micelle concentration of selected non-ionic surfactants (Tween 20,40 and 80) have been investigated using magnetic water(MW)as an aqueous medium.Conductometry technique is used to determine critical micelle concentration.The effect of alcohol addition and temperature variation at the range(293.15 -303.15K) are also pursued. It is concluded that the process of micellization is spontaneous and endothermic because of the observed free energy of micellization (ΔGom) , enthalpy change of micellization (ΔHom), and entropy change of micellization (ΔSom) for the system was also studied.The properties of the non-ionic surfactants were studied, both in absence and presence of
... Show MoreThis study was undertaken to provide more insight on the optimum injection temperature used for the production of PE crates, thereby saving time and money, and improving part quality. The work included processing trails of HDPE crates in an injection
molding machine at five temperatures ranged from 220 to 300°C. Both Rheological and mechanical characterization was conducted in order to understand the effect of injection temperature on the properties of crates. Oven aging was also applied for (4 weeks) to evaluate the long-term thermal stability. The results revealed that producing the crates at a temperature range of (260-280 °C) gives the best rheological and mechanical result. The lowest drop in thermal stability has been observed
The photoconductivity and its dependence on light intensity have been investigated in a-Ge20Se80 thin films as a function of temperature between (293–323)K. The result showed that the photoconductivity and photosensitivity increase with increase of annealing temperature. This behavior is interpreted in terms of the dispersive diffusion –controlled recombination of localized electrons and holes.
The objective of the present study is to determine the effect of Kaolin as a fuel oil additive to minimize the fireside corrosion of superheater boiler tubes of ASTM designation (A213-T22) by increasing the melting point of the formed slag on the outside tubes surface, through the formation of new compounds with protective properties to the metal surface. The study included measuring corrosion rates at different temperatures with and without additive use with various periods of time, through crucible test method and weight loss technique.
A mathematical model represents the relation between corrosion rate and the studied variables, is obtained using statistical regression analysis. Using this model,
... Show MoreSoil is considered one of the main factors of subsidence phenomena which
became continually happen in Baghdad (Ghazalia, Ameria, and Hay al-Amyl)
causing bad effects as shortage of drinking water, traffic jam and formation
swamps.
This thesis depends on soil study to a depth 15 meters, due to its
importance in subsidence. This done through specifying its chemical physical
properties.
Soil within Iraq climate, in case of water stopping for any reason it contract
and shrink away especially when it exposed to high pressure these factors
finally caused subsidence. In case of leakage underground water or that of
damaged water pipes this will contribute to chemical reactions which damage soil
structure and incr
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 MoreTo the Banks capital several uses, including the protection of deposits and this was approved by the Basel Committee, And Finance long-term investments which intended to investment in fixed assets that are essential to the continuation of banking activity, Fixed assets not financed from the funds of the deposit, but the owner equity do this jop. the current research tries to prove the effect of banks capital on fixed assets for a sample of iraqi private banks (bank of baghdad and Iraqi middle east Investment bank), for the period from 2011 until 2014. The research concluded that the capital of bank of baghdad affect on his total fixed assets by (84%), and the capital of Iraqi middle east Investment bank affect on his total fixed assets b
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