The main factors that make it possible to get the corrosion of reinforcing steel in concrete are chloride ions and the absorption of carbon dioxide from the environment, and each of them works with a mechanism which destroys the stable immunity of rebar in the concrete. In this work the effect of carbon dioxide content in the artificial concrete solution on the corrosion behavior of carbon steel reinforcing bar (CSRB) was studied, potentiostatically using CO2 stream gas at 6 level of concentrations; 0.03 to 2.0 weight percent, and the effect of rising electrolyte temperature was also followed in the range 20 to 50ᴼ C. Tafel plots and cyclic polarization procedures were obeyed to investigate the corrosion parameters and pitting susceptibility respectively. The change in the microstructure and morphology of the CSRB after polarization in the simulate concrete solution was studied using optical and atomic force microscopes. The results show that the corrosion rate of the CSRB in artificial concrete greatly increases with the existence of CO2 gas and highly depends on its concentration in the range 0.03 to 2.0% .No sign for pitting corrosion is recorded at all CO2 concentrations and the general corrosion is the main problem in the conditions under consideration.
In this research, the mechanism of cracks propagation for epoxy/ chopped carbon fibers composites have been investigated .Carbon fibers (5%, 10%, 15%, and 20%) by weight were used to reinforce epoxy resin. Bending test was carried out to evaluate the flexural strength in order to explain the mechanism of cracks propagation. It was found that, the flexural strength will increase with increasing the percentage weight for carbon fibers. At low stresses, the cracks will state at the lower surface for the specimen. Increasing the stresses will accelerate the speed of cracks until fracture accorded .The path of cracks is changed according to the distributions of carbon fibers
No-fine concrete (NFC) is cellular concrete and it’s light weight concrete produced with the exclusion of sand from the concrete. This study includes the mechanical properties of lightweight reinforced by steel fiber, containing different proportions of steel fiber. This study was done using number of tests. These tests were density, compressive strength, flexural strength and absorption. These tests of the molds at different curing time. The results of tests that implication of fiber to No. fine concrete did not affect significantly on the compressive strength, While the flexural strength were gets better. Results explained that, the flexural strength of (1%) fiber No- fine concrete molds are four times that of the reference mold
... Show MoreAbstract:
Rabi’a tribe lived on the land of Euphrates since the first century of the
Christ. Then that land becomes her homeland. The Persians tried many times
to drive her away from that land, but with out result.
In the course of time Rabi’a become more knowledgeable of Persia.
This tribe proved her love and sanctification to the land of Euphrates, in the
battle of Dhyqar.
Rabi’a converted to Islam quickly and helped the Muslims to conquer
Iraq with a big number of fighters in many battles like al- Qadisyyah. That
influenced the anger of Mudriat Arab tribes who were their old enemies.
Mudriat tribes did their efforts to reduce the importance of Rabi’a because of
some its branches were among of t
Abstract
Stainless steel (AISI 304) has good electrical and thermal conductivities, good corrosion resistance at ambient temperature, apart from these it is cheap and abundantly available; but has good mechanical properties such as hardness. To improve the hardness and corrosion resistance of stainless steel its surface can be modified by developing nanocomposite coatings applied on its surface. The main objective of this paper is to study effect of electroco-deposition method on microhardness and corrosion resistance of stainless steel, and to analyze effect of nanoparticles (Al2O3, ZrO2 , and SiC) on properties of composite coatings. I
... Show MoreThe aim of the study was to know the factors analysis of scale Bar-On & Parker, post analysis is found fourteen factors for the first degree of the scale. Also we extracted five factors from the second degree.
The scale consists of (60) items , applied on sample of (200) students (Male &Female ) age (15-18) years randomly chosen from preparatory schools . The scale unveiled satis factors validity and reliability. An others aims is to low the emotional Intelligence level and know the difference of statistical in sex , age variable and the specialization variable .The result was no difference of statistical in sex and specialization variable , but the difference appear
... Show MoreChina's economic policy and its huge capabilities operate according to an expansion strategy, especially in investing foreign projects, as the past ten years have witnessed a major development in the elements of comprehensive strength, especially in the economic field, in 2014 China launched the largest initiative in the world, represented by the Belt and Road Project (BRI), which links nearly 70 countries, through this project, a very important region has emerged, which is (the port of cadres) in Pakistan, as China has headed towards that region and given the highest importance that is in its interest in the first place regardless of the great Pakistani interest, This is consistent with its future aspirations, especially after breaking
... Show MoreThis paper reflects the evidence of the Islamic Development Bank's role in building human and institutional capacities in Member States and assisting governments in achieving economic development. The Bank's activities in the area of capacity development are an important part in following up the economic developments, And help governments to build and formulate effective policies and institutions to implement more effective macro policies leading to better economic outcomes. It is therefore helpful to help Member States increase their resources, modernize their banking systems, establish effective legal frameworks and improve Reports on macroeconomic and financial statistics. The Bank has faced many challenges and risks tha
... Show MoreABSTRACT The isolation and characterization of (27) isolate of extreme halophilic bacteria was performed ninteen isolate belonged to the genus Halobacterium which included Hb.halobium. Hb. salinarium, Hb. volcanii. Growth curve and generation time in logarthmic phase was measured and found to be (12.8hr±0.32), (11.2hr±0.2), (9.8hr±0.87), respectivaly. Effect of various concentrations of NaCl, KCI, NH4Cl and MgSO4.7H2O was studied, NaCl was essential for the rod shape rapid growth Rat and pigmentation. Less than 1% concentration caused lysis of bacteria. Yeast extract was the best carbone source as compared with glucose and casamino acid.
A new light-weight nanocarbon prepared by spray-drying method to obtain particle size is 21.7 nm based of polylactic acid biodegradable film in antistatic packaging .Bio carbon (biochar) is obtained from plants and soils to naturally absorb and store carbon dioxide from the atmosphere . Therefor it has been used to support biodegradable polylactic acid (PLA) with to obtain 100% recyclable material.
Using plasticizer thymol of polylactic acid and biochar (bio carbon) as composites were prepared by a solution casting method with (0.5-10)wt% biochar. The composites characterized by FTIR, electrical conductivity, mechanical properties , contact angle and Colar and Brightness . Results show th
... Show MoreIn this paper synthesis and extensive investigation of the microstructural and optoelectronic properties of polyaniline (PANI), Multiwalled carbon nanotube (MWCNTs) and MWCNTs reinforced PANI composites is presented. MWCNTs- PANI composites have been deposited by spin coating on silicon wafer substrate. Fourier Transform Infrared Spectroscopy shows no difference between PANI and its composites. However a change in peaks shape and absorption intensity has been observed. A strong effect of the MWCNTs weight percentage on the PANI/MWCNTs composites has been demonstrated. It was find that the thermal stability improved with increasing MWCNTs content. The optical band gap of the PANI thin