فصلنامه پدافند غیرعامل
سال سوم شماره 2 (پیاپی 10، تابستان 1391)

In this research for consideration of concrete durability against sulphate attack, 48 various concrete mixtures were compared. Three various water-cement ratios -0.35, 0.4, 0.45- have been used.in these mixtures from various percentage of slag, fly ash and silica foam. In which, the water cement ratio for 0% to 40%, silica foam from 0% to 15% and fly ash from 0% to 50%.Results show that reduction of water-cement ratio from 0.45 to 0.35 increases concrete life about 0.8 year. While an Addition of 15% of silica foam has the most important effect on increasing the concrete life from 21 to 52.2 years, While this effect is 23.2 and 26.9 years for slag and fly ash in turn.

Defense is an instinctive issue, meaning that it has roots in inner part and instinct of humans and is not related to a certain time and place or area. This instinctive tendency has such domination on the spirit of an individual and society that in difficult conditions will force him to utilize the power of wisdom to make the best use of natural and climate and existing facilities and to implement defense solutions compatible with the threats to protect himself, his home and city, as well. In the distant past, the people of Noosh Abad made efforts to establish a dynamic defense network in the desert and the erected a town deep underground where not only no material was used in its construction but also they produced some material out of its construction and they used it in making walls and towers around the town. The residents of Noosh Abad developed an underground town, within many years, where they could shelter in time of danger and continue their lives for a long time and be safe from their enemy. The present research has been done in historical form and is of applied sort. At first, the theoretical principles of the research have been explained and then the information about the town of Owi and its passive defense has been collected. In the end, upon review, the passive defense measures taken in the town of Owi have also been described. This article intends to pursue the ancient town of Owi and to present the passive defense measures there.

The high power electromagnetic weapon (HPM) is the technology that is considered a threat to electronic systems. By producing HPM pulse, an enormous energy with high penetrating power in is released a short time which causes an unstable current with high voltage to be established which in turn destroys the electronic parts of systems such as semi-conductors. This article first explains methods of producing high power electromagnetic energy and then a brief introduction of this weapon along with its structure and the way it is produced, is presented. The parameters of the high power electromagnetic weapon and how it can penetrate the electronic systems are further expressed and its effect on these systems is reviewed, as well. Finally, measures taken to protect these systems, taking into account the kind of vulnerability against high power energy pulses, are also reviewed and the appropriate solutions are further presented.

Xenon is one of the fission fragments which is produced in nuclear reactors and nuclear explosions with variety of its isotopes. With definition of special isotopes ratio of this element, we can specify the production base of these isotopes such as a nuclear explosion and leakage of a reactor or nuclear wastes. We can also determine the time of event occurrence. This paper describes the measurement of the variety of Xe isotopes; the production of spectrums associated with Xe different sources using the MCNP code, obtaining the activity and Xe different isotopes activity ratios and their sorting in oerder to determine the production source with neural network to design an early warning system.

One of the most important problems threatening modern humans is the usage of chemical, biological and nuclear agents by terrorist groups. Easy availability and low cost of chemical agents compared to biological and nuclear agents make them favorably applicable to terrorists. In this paper, threatening of water resources by chemical warfare agents have been investigated and based on parameters such as stability and solubility in water, volatility from water and chlorine resistance, two agents, VX (nerve agent) and sulfur mustard (HD) have been presented as major threatening agents for water resources.

Among the various forms of malware, botnets are emerging as the most serious threat against cyber security, they are used for malicious purposes such as sending spam, launching Distributed Denial of Service (DDoS) attacks, Spying and theft of confidential information, and identity theft. Botnets, are remotely controlled by the attackers, and whose members are located in homes, schools, businesses, and governments around the world. The defining characteristic of botnets is the use of command and control channels through which they can be updated and directed. Survey of botnet and its attacks and also botnet detection and defense are related to passive defense in the field of information technology and one of the important aspects of it, is cyber attacks against our country that mainly have properties of botnets. In this paper, We first discuss fundamental concepts of botnets, then command and control techniques are introduced and finally a brief comparison of these techniques is explained. Subsequently, we introduce several related attacks and malicious operation of botnets and then we point out theirr latest targets, and eventually, some cyber attacks, especially those that are against our country infrastructures have been discussed and according to this study, some discussions are also presented about their similarity to botnet attacks, and finally, conclusions are drawn and recommendations are made.