AES-128, the NIST P-256 elliptic curve, DSA-3072, RSA3072, and various higher-level protocols are frequently conjectured to provide a security level of 2. Extensive cryptanalysis of these primitives appears to have stabilized sufficiently to support such conjectures. In the literature on provable concrete security it is standard to define 2 security as the nonexistence of high-probability attac...

background: high density concrete is extensively used for efficient radiation attenuation in radiotherapy rooms and nuclear reactors. over the past eight years, some efficient galena-based concrete samples for shielding x or gamma rays was produced. the goal of this study was to produce a novel high density concrete against neutron and photon radiations using tourmaline and galena. materials an...

there is a worldwide interest in using fibers of different types in concrete mixtures. in this regard, as the use of pet fibers has gradually increased during the last decade, this study aims to investigate the effects of pet fibers on the mechanical properties of hardened concrete and the workability of fresh concrete. to this end, different contents of pet fibers (pc= %0, %0.5, %1 and %1.5) a...

one of the main factors of premature deterioration of concrete structures is the corrosion of reinforcements. chloride penetration of concrete is one of the main reasons of this phenomenon. therefore, to have durable structure, it is necessary to have concretes with low permeability.there are various methods to evaluate permeability of concrete. finding a relationship between them can be useful...

By increasing the demolition of old concrete structures and the interest of civil industries to consume cheaper materials, using Recycled Concrete Aggregate (RCA) can cause environmental protection and decrease the construction costs. On the other hand, the high potential of Recycled Aggregate Concrete (RAC) in concrete industry was established by extensive experimental researches were performe...

In this paper, the effect of Polypropylene Fibers added to concrete on strength and thermal resistance of high strength concrete has been investigated. Therefore, five tests have been carried out to reach this goal which it includes; effect of weight percent of polypropylene fibers on mechanical properties of concrete, effect of fiber’s length on the strength of high strength concrete, effect o...