A Laced Reinforced Concrete (LRC) structural element comprises continuously inclined shear reinforcement in the form of lacing that connects the longitudinal reinforcements on both faces of the structural element. This study conducted a theoretical investigation of LRC deep beams to predict their behavior after exposure to fire and high temperatures. Four simply supported reinforced concrete beams of 1500 mm, 200 mm, and 240 mm length, width, and depth, respectively, were considered. The specimens were identical in terms of compressive strength ( 40 MPa) and steel reinforcement details. The same laced steel reinforcement ratio of 0.0035 was used. Three specimens were burned at variable durations and steady-state temperatures (one hour at 500 °C and 600 °C, and two hours at 500 °C). The flexural behavior of the simply supported deep beams, subjected to the two concentric loads in the middle third of the beam, was investigated with ABAQUS software. The results showed that the laced reinforcement with an inclination of 45˚ improved the structural behavior of the deep beams, and the lacing resisted failure and extended the life of the model. The optimal structural response was observed for the specimens. The laced reinforcement improved the failure mode and converted it from shear to flexure-shear failure. The parametric study showed that the lacing bars remarkably improved the strength of the deep beams and they were not affected more by the steady-state temperature and duration. Furthermore, a greater increase in load-carrying capacity was associated with an increase in the flexural diameter of approximately 12 and 16 mm by approximately 24.77% and 87.61%, respectively, compared to the reference LRC deep beams.
Many faces are exposed to degradation, discoloration, changes in humidity. The primary objective has improved some properties of hybrid nanocomposites materials that used for restoring of the function maxillofacial prosthesis and improving the esthetic. In the present research different lengths chopped and continuous of ultrahigh molecular weight polyethylene (UHMWPE) fiber was added at selected percentage (0.0, 0.2% and 1%) to polymer blend composite (95%SR /5%PMMA: 0.2% Pomegranate Peels Powder (PPP)) for developing the properties of silicone rubber used for the maxillofacial prosthesis applications. Some mechanical and physical properties were done on the all prepared samples. The results showed that all properties have improved when add
... Show MoreThe researcher of human history finds that the first social relations on earth were represented by the violence of Adam, peace be upon him, Cain and Abel. Violence has been a phenomenon of life and society. The history of history is full of all forms of violence and its forms. It speaks of cruelty, oppression and states. History began, in some of its chapters, written with the blood of the victims. It is a testimony to the cruelty of human beings. His human nature and his sin have played a major role that can not be overlooked in the development of important and fundamental developments in some historical turning points where violence was a necessity for life, and its launching change, renewal and reform, and major revolutions in human h
... Show MoreIraq has seen many changes at the social, economic and political levels. This led to cause many shifts in the structure of its society and imposed great challenges reflected in the behavior and awareness of that society in general and youth in particular.
Those changes made the Iraqi society undergoing the transformation of value and culture aspects formed a political awareness that caused cultural and political diversity within the family and society. A greater openness to the outside world caused by the communication revolution, as the world has witnessed during the past two decades, has helped in making that change. Iraq had its share of media and political openness, which were included after the US occupation in 2003. As a re
... Show MoreA novel demountable shear connector for precast steel‐concrete composite bridges is presented. The connector uses high‐strength steel bolts, which are fastened to the top flange of the steel beam with the aid of a special locking nut configuration that prevents slip of bolts within their holes. Moreover, the connector promotes accelerated construction and overcomes typical construction tolerances issues of precast structures. Most importantly, the connector allows bridge disassembly, and therefore, can address different bridge deterioration scenarios with minimum disturbance to traffic flow, i.e. (i) precast deck panels can be rapidly uplifted and replaced; (ii) connectors can be rapidly removed and replaced; and (iii) steel beams can b
... Show MoreIn this paper, the fill factor of the N749/TiO2 solar cell is studied and calculated using the analysis method at standard conditions; i.e., T=300k and 100 mW/cm2 irradiation.. The current density was derived and calculated using the donor-acceptor model according to the quantum transfer theory in DSSC solar cells. We estimate the influence parameters in DSSC that's an equivalent circuit to the I-V curves for three solvents. The fill factor parameters of the N749/TiO2 device are found to be 0.137,0.146 and 0.127 with Butanol, Ethanol and Acetonitrile for carrier concentration . 1018 1/cm3 respectively. The photovoltaic characteristics ISc , Vco<
... Show MoreThe current study deals with host-guest complex formation between cucurbit [7] urils as host and lansoprazole as guesti using PM3 (semi empirical molecules orbital calculations) also DFT calculations. In this complex, the formation of hydrogen bonding may be occurred through portal oxygen atoms(O2) of cucurbit [7] urils and amine groups (NH 2 )of the drug. The energies of HOMO and LUMO orbital’s have been computed for the host guest complex and its components. The result of the stabilization energy explained a complex formation.
This research aims to create lightweight concrete mixtures containing waste from local sources, such as expanded polystyrene (EPS) beads and waste plastic fibers (WPFs), all are cheap or free in the Republic of Iraq and without charge. The modern, rigid, and mechanical properties of LWC were investigated, and the results were evaluated. Three mixtures were made, each with different proportions of plastic fibers (0.4%, 0.8%, 1.2%), in addition to a lightweight concrete mixture containing steak fibers (0.4%, 0.8%, 1.2%), in addition to a lightweight concrete mixture. It contains 20% EPS. The study found that the LWC caused by the addition of WPFs reduced the density (lightweight) of the concrete mixtures because EPS tends
... Show Morethe behavior of the first-order black and gray solitons propagtedin optical fiber in the presence of frequency chirp is studied analytically and numerically results show that phase profile of black solitons changes abruptly
In the present investigation two different types of fiber reinforced polymer composites were prepared by hand lay-up method using three different parameters (curing temperature, pressing load and fiber volume fraction). These composites were prepared from the polyester resin as the matrix material reinforced with glass fibers as first group of samples and mat Kevlar fibers as the second group, both with different volume fractions (4%, 8%, and 12%) of fibers. They were then tested by tensile strength and impact strength. The main objective in this study is to use Taguchi method for predicting the better parameters that give the better tensile and impact strength to the composites, and then preparing composites at
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