Two novel demountable shear connectors for precast steel-concrete composite bridges are presented. The connectors use high-strength steel bolts, which are fastened to the steel beam with the aid of a special locking configuration that prevents slip of bolts within their holes. Moreover, the connectors promote accelerated construction and overcome typical construction tolerances issues of precast structures. Most importantly, the connectors allow bridge disassembly, and therefore, can address different bridge deterioration scenarios with minimum disturbance to traffic flow, i.e. (1) precast deck panels can be rapidly uplifted and replaced; (2) connectors can be rapidly removed and replaced; and (3) steel beams can be replaced, while precast decks and shear connectors can be reused. A series of push-out tests and a beam test were conducted to assess the behavior of the connectors and quantify the effect of important parameters. The experimental results showed that shear resistance and slip capacity can reach 2.5 and 2.7 times respectively of those of welded shear studs along with superior stiffness and strength against slab uplift. Additionally, shear stiffness of M16 mm LNSC was equal to that of M19 mm welded studs. Identical tests reveal negligible scatter in the shear load – slip displacement behavior. Design equations are proposed to predict the shear resistance with minimum deviations.
The study concerned the embryonic development of spinal cord of white choeked bulbul Pycnonotus leucotis. The spinal cord at the age 40 hour’s incubation from the neural tube and its tissue wall is composed of two layers, the ependymal layer and mantle layer. The spinal cord differentiation is completed at the age 7 day’s incubation, its, were we notice that the central canal is clear and cavity lined with neurons and we note the arrangement of gray matter in the form of the letter H and its inside and it is characterized by dorsal and ventral horns and the gray matter substance and note the formation of dorsal medium spetum and ventral medium fissure.
Background: Maxillary sinusitis can arise after sinus floor elevation surgery and should be treated immediately to prevent further complications which included dental implants failure, graft lost, and oro-antral fistula. This is the first systematic review to assess the incidence, causes, and treatment of sinusitis after sinus lift surgery. Materials and methods: An electronic search included MEDLINE (PUBMED) data base site was carried out for articles involving development of sinusitis after sinus lift surgery from September 1997 up to April, 8, 2017. The search was done and reviewed by two independent authors. Results: The total results of electronic search were (182) abstracts and articles, the extracted articles which involved develo
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The behavior of thinking is consider one of the modern concepts that appear in the last 20 years, this concept has attracted the attention of psychologists and researchers for thinking has a great role in many fields like teaching ,educational,economical,cultural and social fields.
One of thinking manner is imaginal thinking that has a great role in human civilization. imaginal thinking lead to innovation ,poems, inventions and arts. imaginal thinkingled to highscores in talented schools by escalating their thinking range and solving problems that consider one of organized and free assumption thinking.
The development of problems thinking strategies reflect the development of organized brain process ability.
That studies assumes
The study aimed to monitor the concept of reputation in the previous literature, its relationship to mental image and identity, and to reveal recent trends in its measurement Techniques.
The study relied on a descriptive approach using library survey and comparative analysis, and the study reached following conclusions:
Despite the beginning of the first signs of reputation In the fifties of the last century, however, Defining and standardizing the concept with clear and specific dimensions began in the 1990s and the beginning of the third millennium. The concept of reputation refers to the stakeholders’ overall evaluation of organizations, which reflects their perceptions of
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Abstract
In this investigation, Al2O3 nano material of 50nm particles size were added to the 6061 Al aluminium alloy by using the stir casting technique to fabricate the nanocomposite of 10wt% Al2O3. The experimental results observed that the addition of 10wt% Al2O3 improved the fatigue life and strength of constant and cumulative fatigue. Comparison between the S-N curves behaviour of metal matrix (AA6061) and the nanocomposite 10wt% Al2O3 has been made. The comparison revealed that 12.8% enhancement in fatigue strength at 107cycles due to 10wt% nano reinforcement. Also cumulative fatigue l
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Background:Â Various fluids in the oral environment can affect the surface roughness of resin composites. This in vitro study was conducted to determine the influence of the mouth rinses on surface roughness of two methacrylate-based resin (nanofilled and packable composite) and siloraine-based resin composites.
Materials and methods: Disc-shaped specimens (12 mm in diameter and 2mm in height) were prepared from three types of composi
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This research is carried out to study the effect of the external post-tensioning technique on the flexural capacity of simply supported composite castellated beam experimentally. In this research, seven composite castellated beams having the same dimensions and material properties were cast and tested up to failure by applied two concentrated loads at 700 mm from each end. Two external strands of 12.7 mm diameter were fixed at each side of the web of strengthening beams and located at depth 180 mm from top fiber of the section (dps) at each end of the beam. The strands have been tensioned by using a hydraulic jack with a constant stress of 100 MPa. This research aims to study the effect of the strengthening by different shapes of st
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