This paper presents a study (experimentally) for strengthening reinforced concrete (RC) beams with Near-Surface-Mounted (NSM) technique. The use of this technique with CFRP strips or rebars is an efficient technology for increasing the strength for flexure and shear or for repairing damaged reinforced concrete (RC) members. The objective of this research is to study, experimentally, RC beams either repaired or strengthened with NSM CFRP strips and follow their flexural behavior and failure modes. NSM-CFRP strips were used to strengthen three RC beam specimens, one of them was initially strengthened and tested up to failure. Four beam specimens have been initially subjected to preloading to 50% and 80% of ultimate load. Two of the specimens were either repaired or strengthened with NSM-CFRP strips. All the repaired/strengthened pre-damaged beams have been tested up to failure by using compression-testing machine. An appropriate-scale model was adopted. All the specimens have a cross-sectional dimension of 150 mm with an effective span of 110 mm. Depends on the experimental results, a better performance of the strengthened concrete specimens was obtained in both strength and serviceability. As a comparison with the control beam specimen, all the repaired specimens show a very good increase of about 40% in the load-carrying capacity and a high improvement in resistance to cracking of about 120% in NSM. On the other hand, the test results of NSM CFRP-strengthened concrete specimens with a preloading of 50% and 80% of the ultimate load show an increase of about 9% to 20% in the load-carrying capacity, for 50% and 80% pre-loading, respectively an improvement in deflection of about 2% to 27% in NSM, for 80% and 50% pre-loading, respectively.
The study found a number of results. The most prominent were the low married during the years of the study in 1997-2012. The study also showed the level of administrative units that the percentage of widows and single rise in urban and rural decline. This is due to the different nature of urban and rural society of the behavior and social habits and traditions.As the proportion of divorced and unmarried are decreased in urban and increase proportion in the countryside, and this is due to the influence of the rural population in the urban centers. As well as the study showed that there was a significant effect of the economic and social factors and other factors on marital status on its parts in the study area.
A numerical investigation is adopted for two dimensional thermal analysis of rocket thrust chamber wall (RL10), employing finite difference model with iterative scheme (implemented under relaxation factor of 0.9 for convergence) to compute temperature distribution within thrust chamber wall (which is composed of Nickel and Copper layers). The analysis is conducted for different boundary conditions: only convection boundary conditions then combined radiation, convection boundary conditions also for different aspect ratio (AR) of cooling channel. The results show that Utilizing cooling channels of high aspect ratio leads to decrease in temperature variation across thrust chamber wall, while no effects on heat transferred to the
... Show MoreIn this contribution, density functional theory-based calculations have been carried out to assess the electronic, photocatalytic and optical properties of Ce1-xTixO2 system. Ti incorporation leads to a decrease of Ce 4f states and enhancement of Ti 3d states in the bottom of conduction band. Furthermore, it was found that doping ceria with Ti-like transition metals could evidently shift the absorption of pure CeO2 towards higher wavelength range. These findings can provide some new insights for designing CeO2-based photocatalysts with high photocatalytic performance. To the best of our knowledge, this investigation calculates Mullikan’s charge transfer of Ce1-xTixO2 system for the first time. Charge transfer reveals an ionic bond between
... Show MoreIn this research an analysis for improving the fatigue behavior (safety factor of fatigue) of non- articular prosthetic foot (SACH) in the region (Bolt Adapter).The laser peening was carried to the fatigue specimens to improving the fatigue properties of bolt’s material. The tests of mechanical properties and fatigue behavior were carried for material that the bolt manufacture from it, a region where the failure occur and inserted of these properties to the program of engineering analysis (Ansys) to calculate the safety factor of fatigue. The results showed that the safety factor after hardening by laser is increased by 42.8%.
In this work Polyynes was synthesized by pulse laser ablation of graphite target in ethanol solution. UV-Visible Spectrophotometer, Fourier Transform Infrared Spectroscopy (FTIR) and Transmission electron microscopy (TEM) were used to study the optical absorption, chemical bonding, particle size and the morphology. UV absorption peaks coincide with the electronic transitions corresponding to linear hydrogen – capped polyyne (Cn+1H2), the absorption peaks intensity increased when the polyynes were produced at different laser energies and the formation rats of polyynes increased with the increasing of laser pulse number. The FTIR absorption peak at 2368.4 cm-1, 1640.0 cm-1 and 1276.
... Show MoreTwelve species of philodromid crab or running crab spiders (Philodromidae) have been recorded in Armenia. Nine species are new to the spider fauna of this country: Philodromus cespitum (Walckenaer, 1802); Philodromus emarginatus (Schrank, 1803), Philodromus rufus Walckenaer, 1826; Rhysodromus histrio (Latreille, 1819), Thanatus atratus Simon, 1875; Thanatus formicinus (Clerck, 1757); Thanatus imbecillus L. Koch, 1878; Thanatus vulgaris Simon, 1870 and Thanatus pictus L. Koch, 1881.
In this work, ZnO nanostructures for powder ZnO were synthesized by Hydrothermal Method. Size and shape of ZnO nanostructureas can be controlled by change ammonia concentration. In the preparation of ZnO nanostructure, zinc nitrate hexahydrate [Zn(NO3)2·6H2O] was used as a precursor. The structure and morphology of ZnO nanostructure have been characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD). The synthesized ZnO nanostructures have a hexagonal wurtzite structure. Also using Zeta potential and Particle Size Analyzers and size distribution of the ZnO powder
This study examines the opportunity presented by the COVID-19 pandemic for city planners and leaders to learn from the crisis and build resilient cities with long-term societal, economic, and environmental resilience against future disasters. The research focuses on the relationship between urban planning and policies and the extent of their resilience, particularly in response to pandemic-related disasters. The study evaluates the ability of the city of Baghdad to respond to the pandemic and identifies gaps in its resilience. The study uses the scorecard measurement instrument to examine the disaster resilience of cities, with a focus on governance and financial capability, disaster planning and preparedness, and disaster response
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