This study aimed at evaluating the torsional capacity of reinforced concrete (RC) beams externally wrapped with fiber reinforced polymer (FRP) materials. An analytical model was described and used as a new computational procedure based on the softened truss model (STM) to predict the torsional behavior of RC beams strengthened with FRP. The proposed analytical model was validated with the existing experimental data for rectangular sections strengthened with FRP materials and considering torque-twist relationship and crack pattern at failure. The confined concrete behavior, in the case of FRP wrapping, was considered in the constitutive laws of concrete in the model. Then, an efficient algorithm was developed in MATLAB environment to accomplish the analysis, solve the appropriate equations, and calculate the torsional moment and angle of twist at all points. The parametric study considered the effect of effective fiber strain to reach a better prediction for the full torsional behavior. The model was able to predict the torsional behavior of the RC beams strengthened with FRP materials before and after cracking stages with reasonable accuracy.
Modified asphalt is considered one of the alternatives to address the problems of deficiencies in traditional asphalt concrete, as modified asphalt addresses many of the issues that appear on the pavement layers in asphalt concrete, resulting from heavy traffic and vehicles loaded with loads that exceed the design loads and the large fluctuations in the daily and seasonal temperatures of asphalt concrete. The current study examined the role of polyphosphoric acid (PPA) as a modified material for virgin asphalt when it was added in different proportions (1%, 2%, 3%, 4%) of the asphalt weight. The experimental program includes the volumetric characteristics associated with the Marshall test, the physical properties, and th
... Show MoreThis paper presents the results of experimental investigation carried out on concrete model piles to study the behaviour of defective piles. This was achieved by employing non-destructive tests using ultrasonic waves. It was found that the reduction in pile stiffness factor is found to be about (26%) when the defect ratio increased from (5%) to (15%). The modulus of elasticity reduction factor as well as the dynamic modulus of elasticity reduction factor increase with the defect ratio
The presence of construction wastes such as clay bricks, glass, wood, plastic, and others in large quantities causes serious environmental problems in the world. Where these wastes can be used to preserve the natural resources used in construction and reduce the impact of this problem on the environment, it also works to reduce the problem of high loads of concrete blocks. Clay bricks aggregate (AB) can be recycled as coarse aggregate and replaced with volumetric proportions of coarse aggregate by ( 5% and 10%), as well as the use of clay brick powder (PB) by replacing its weight of cement (5% and 10%) and reduced in the manufacture of concrete blocks (blocks). Four mixtures will be prepared and tested to learn how to re
... Show MoreIn this research, A thin film of Rhodamine B dye and TiO2 Nanoparticles doped in PMMA Polymer has been prepared by a casting method. The sample was spectrum absorption by UV-Vis. The nonlinear optical properties were measured by Z- scan technique using Nd:YAG laser with (1064 nm) wavelength. The nonlinear refractive index (n2) and nonlinear absorption coefficient (β) were estimated for the thin film for different energies of the laser, n2 and β were decreased with increasing intensity of incident laser beam. Also, the type of β was two-photon absorption and n2 negative nonlinear reflective.
The influence of fear on the dynamics of harvested prey-predator model with intra-specific competition is suggested and studied, where the fear effect from the predation causes decreases of growth rate of prey. We suppose that the predator attacks the prey under the Holling type IV functional response. he existence of the solution is investigated and the bounded-ness of the solution is studied too. In addition, the dynamical behavior of the system is established locally and globally. Furthermore, the persistence conditions are investigated. Finally, numerical analysis of the system is carried out.
Background. Dental implantation has become a standard procedure with high success rates, relying on achieving osseointegration between the implant surface and surrounding bone tissue. Polyether ether ketone (PEEK) is a promising alternative to traditional dental implant materials like titanium, but its osseointegration capabilities are limited due to its hydrophobic nature and reduced surface roughness. Objective. The aim of the study is to increase the surface roughness and hydrophilicity of PEEK by treating the surface with piranha solution and then coating the surface with epigallocatechin-3-gallate (EGCG) by electrospraying technique. Materials and Methods. The study includes four groups intended to investigate the effect of pir
... Show MoreThis is a descriptive study that used the survey method, it’s aimed to identify the topics and frameworks of diplomatic and political issues covered by the news of the website of the Iraqi Ministry of Foreign Affairs, through the content analysis method applied on a sample selected in a systematic random manner for news published in the year 2021. The sample included (191) news equivalent to (20%) of the total study population of (942). The study reached some results, the most important of which were as follows: The political issue, in its general sense, grabbed the most prominent attention among the various issues and events focused on by Iraqi diplomacy: "international cooperation", "bilateral cooperation", and then "regional politic
... Show MoreThe purpose of the research is to investigate the response of stock prices of companies that issued debt instruments (bonds) listed on the Abu Dhabi Securities Exchange for information content from the Moody's first credit rating announcements for the period 1 January 2005 - 30 May 2017. The study methodology was used to verify the existence of this response by the market and the Market efficiency of the Semi-strong shape. The research focused on testing the impact of the initial announcement.The research showed that there is an influential information content to announce credit ratings in stock prices, with different responses between negative and positive. It was also found that the industrial sectors sample research separately d
... Show MoreThe current study aims at the extent of determining the interest of the Ministry of Higher Education and Scientific Research and its various departments in the process of strategic foresight, and whether this interest is reflected in its strategic decisions if the study relies on an exploratory and analytical approach and has targeted managers in the higher management within this ministry, and the questionnaire has also been used as a basic tool for collecting For data, the study population was (94), (89) questionnaires were distributed, (86) questionnaires were retrieved, and usable questionnaires amounted to (83). The sub-variable had the highest impact on strategic decision-making (intuition), as this research demonstrated the
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