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...

Background: In megavoltage radiotherapy rooms, ordinary concrete is usually used due to its low construction costs, although higher density concrete are sometimes used, as well. The use of high-density concrete decreases the required thickness of the concrete barrier hence, its disadvantage is its high cost. In a nuclear reactor, neutron radiation is the most difficult to shield. A method for p...

regarding the increasing demand for lightweight concrete especially lightweight structural concrete, and safety requirements underlined in 2800 iranian standard, research to achieve the optimized results in lightweight concrete production seems inevitable. since, one of the commonly used methods for producing the light eight concrete, utilizes the light weight aggregates with significant role i...

background: biological shielding of nuclear reactors has always been a great concern and decreasing the complexity and expense of these installations is of great interest. in this study, we used datolite and galena (daga) minerals for production of a high performance heavy concrete. materials and methods: datolite and galena minerals which can be found in many parts of iran were used in the con...

This Engineer Technical Letter (ETL) discusses the special problem areas and concerns related to RCC construction in order to assure that the concrete properties required are ultimately realized in the completed structure. A quality RCC product requires a coordinated effort between the structural designer, the materials engineer, the materials laboratory, and those responsible for field quality...

Signature schemes that are derived from three move identification schemes such as the Fiat-Shamir, Schnorr and modified ElGamal schemes are a typical class of the most practical signature schemes. The random oracle paradigm [1,2,12] is useful to prove the security of such a class of signature schemes [4,12]. This paper presents a new key technique, “ID reduction”, to show the concrete security ...

In recent work, Ishai, Prabhakaran and Sahai (CRYPTO 2008) presented a new compiler (hereafter the IPS compiler) for constructing protocols that are secure in the presence of malicious adversaries without an honest majority from protocols that are only secure in the presence of semi-honest adversaries. The IPS compiler has many important properties: it provides a radically different way of obta...

We present the results of an experiment examining the extent to which individuals will tolerate delays when told that such delays are for security purposes. In our experiment, we asked 800 Amazon Mechanical Turk users to count the total number of times a certain term was repeated in a multipage document. The task was designed to be conducive to cheating. We assigned subjects to eight between-su...