The Cleveland-Lloyd Dinosaur Quarry (CLDQ) is the densest deposit of Jurassic theropod dinosaurs discovered to date. Unlike typical Jurassic bone deposits, it is dominated by the presence of Allosaurus fragilis. Since excavation began in the 1920s, numerous hypotheses have been put forward to explain the taphonomy of CLDQ, including a predator trap, a drought assemblage, and a poison spring. In...

The Earth's age and early differentiation history are re-evaluated using updated isotopic constraints. From the most primitive terrestrial Pb isotopic compositions found at Isua Greenland, and the Pilbara of Western Australia, combined with precise geochronology of these localities, an age 4.49 +/- 0.02 Ga is obtained. This is interpreted as the mean age of core formation as U/Pb is fractionate...

Samples of ferromanganese nodules from several localities in Lake Michigan have been analyzed for their minor element content utilizing neutron activation techniques. The thorium and uranium levels in Lake Michigan nodules exhibit marked dissimilarities with marine nodules. The radium content of these freshwater nodules is substantially higher than the reported marine values. The concentrations...

Hybrid fiber reinforced concrete (HFRC) consisting of two or more different types of fibers has been widely investigated because of its superior mechanical properties. In the present study, the effect of the addition of steel (0.25%, 0.5%, 0.75%, and 1% of concrete volume) and Polypropylene (0.2%, 0.4%, and 0.6% of concrete volume) fibers on the surface scaling resistance of concrete, depth of ...

Characteristics of produced concrete become changedthrough changingthe characteristics of materials constituting the concrete. These changes include: The quality of cement, the real ration of water to cement: with neglecting the further water within the aggregates or lack of that, the consideredratio fluctuates and the characteristics of the aggregate which are related to the following dimensio...

Nowadays, concrete with strength higher than 50 MPa is utilized due to the ever increasing need for higher strength and prolonged healing properties. Despite the widespread use of high-strength concrete, only a few research projects have been conducted on the punching shear strength of high-strength concrete slabs. Reinforced concrete flat slabs are widely employed in structural systems. The lo...

Nanotechnology will serve as a suitable solution to achieve high performance in future construction and construction. Using this new technology, creativity and innovation can be achieved in the building industry. one of these new technologies of smart concrete is that in recent years, many researches and experiments have been done in scientific research centers around the world, so that the con...

this paper is based on an experimental research that examined the effects of concrete`s major parameters on durability of concrete pavements and curbs under freezing and thawing cycles. these parameters include concrete mix design parameters such as water-cement ratio, fine aggregate percentage and using air entraining admixture and simulating real freeze-thaw cycles that infrastructures underg...

    Freezing and thawing resulting from the ingression of water into concrete causes cracking or spalling. Corrosive ions such as chloride or sulfate penetrate the concrete surface and eventually reach the reinforcing steel. This causes the steel to corrode.     Because of the high maintenance and replacement costs, responsible officials should be increasingly concerned about the growing number...