ABSTRACT  Introduction: Recently uses of medium and high energy x-rays has been increased in Iran and radiotherapy centers along with a variety of accelerators have been installed in some provinces. In the other hand there is no sufficient skill in designing and making radiotherapy treatment rooms. This study was conducted to evaluate the efficacy of different m...

Given the development of construction industry and design and implementation of high rise buildings with complex sections and various geometrical forms, the use of self-compacting concretes has received the attention of construction engineers and provided great advantages. Due to the increasing air pollution in cities, governments encounter the important issue of repelling the pollutants in whi...

Quantum secure direct communication protocols offer confidential transmission of classic information over the quantum channel without a prior key agreement. The ping-pong based protocols provide asymptotic security and detailed analysis of the security level provided by each variant of the protocol is required. The paper presents a general method of calculation of the eavesdropped information a...

A mathematical model for the description of drying shrinkage of autoclaved aerated concrete (AAC) is presented, bringing together the hygrothermal and mechanical considerations. The verification of the model is done using an approximation of a real laboratory experiment. Then, the applicability of the model is demonstrated by a numerical simulation of drying shrinkage and wetting expansion of A...

Cryptographic puzzles (or client puzzles) are moderately difficult problems that can be solved by investing non-trivial amounts of computation and/or storage. Devising models for cryptographic puzzles has only recently started to receive attention from the cryptographic community as a first step toward rigorous models and proofs of security of applications that employ them (e.g. Denial-of-Servi...

For more than 100 years, the primary theme underlying the NBS/NIST staff contribution to the crystallography of building materials has been the development of an improved understanding of concrete materials performance. Over that time period, portland cement concrete has become one of the most important of our construction materials for roads, buildings, and other large municipal structures. At...

Cracking due to temperature and restraint in mass concrete is an important issue. A temperature stress testing machine (TSTM) is an effective test method to study the mechanism of temperature cracking. A synchronous closed loop federated control TSTM system has been developed by adopting the design concepts of a closed loop federated control, a detachable mold design, a direct measuring deforma...

We present PEP, which is a new construction of a tweakable strong pseudo-random permuta-tion. PEP uses a hash-encrypt-hash approach which has recently been used in the constructionof HCTR. This approach is different from the encrypt-mask-encrypt approach of constructionssuch as CMC, EME and EME∗. The general hash-encrypt-hash approach was earlier used byNaor-Reingold to provide ...

Manufactured sand differs from natural sea and river dredged sand in its physical and mineralogical properties. These can be both beneficial and detrimental to the fresh and hardened properties of concrete. This paper presents the results of a laboratory study in which manufactured sand produced in an industry sized crushing plant was characterised with respect to its physical and mineralogical...

My research activity so far seems to lie in two main areas, which I have called noncommutative algebra and concrete mathematics for the purposes of this summary. The following contains a description of past research and a discussion of topics on which (at date of writing) I think I would work in the next few years, if I were on a desert island (with a reasonable library). Of course, things have...