جستجوی مقالات مرتبط با کلیدواژه "camouflage" در نشریات گروه "پدافند غیرعامل"

Reducing the amount of radiated energy from military equipment such as helicopters leads to an increase in the possibility of hiding or camouflage them. In this study, the parameters affecting radiation heat transfer, including heat transfer equations, the effects of diffusion environment, the heat flux reaching the surface of the helicopter body, and the geometry of the helicopter body surface are investigated. Then, software simulation is performed in the presence of sunlight and at different angles and its effect on thermal sensors. The results obtained from the simulation show that the angle of the helicopter and the absorption coefficient are the effective characteristics in thermal radiation. By changing the angle of the helicopter, the visibility coefficient between the sensor and the helicopter changes, and as a result, the amount of radiation in between also changes, and these changes also change with the change in color,   material, surface and other factors affecting the absorption coefficient.

Hiding military equipment is one of the essential factors in establishing military superiority. Nowadays, most of the military devices, from night vision cameras to cameras mounted on military weapons, are equipped with infrared cameras. By using the temperature emitted from the objects, they can be identified in different situations, including absolute darkness. The multiple capabilities of these cameras in monitoring the other party's military capabilities have made camouflage technologies in this field more important, so that the development and research of new infrared camouflage methods and thermal cameras have become the focus of strategic development of countries around the world. This paper is a review paper in the field of infrared cameras, which is not similar in any other reference, and with a comprehensive view, while explaining the applications and principles of operation of infrared systems, it examines various methods of countermeasure with this type of camera. Also, at the end of the paper, a comprehensive classification of methods to countermeasure with this type of camera is presented.

Given the essential role of individual trenches in the survival and mission accomplishment of insider forces, especially in the plains, it is obvious that the enemy uses a variety of aerial and space sensors for their detection and identification. Imaging cameras are one of the main systems for detecting targets, especially at night. The main agent that causes the detection of a trench in thermal images is the thermal anomaly in its opening with respect to the surrounding environment. This study intends to use field observations and visual assessment methods to investigate the possibility of identifying fighters stationed in foxhole trenches and to provide measures and considerations to prevent the detection of foxhole trenches in plain areas. For this purpose, 36 scenarios in different positions namely: person standing next to the trench, person standing in the trench and person sitting in the trench, two different times, bright and dark days at different distances, are considered. Based on the experimental results obtained, it is possible to detect foxhole trenches without camouflage in plain areas at close range. Also, the best type of camouflage is the use of dry and lifeless plants related to the area.

Camouflage is considered to be a passive defense principle. It is clear that, despite dramatic advances in the production of detectors and sensors, traditional camouflage technique does not have the necessary effectiveness to deal with these detectors, and development of detection and detection systems should be considered in the context of developing new solutions to countermeasure. One of these strategies is smart or adaptive camouflage. In this kind of camouflage, the goal is to react actively to environmental changes and to keep itself hidden from the eyes of the observer. In recent years, a number of researchers have made feasibility studies for such systems in research projects. These studies are not generally in the visible spectrum or have not led to production of a camouflaged system. In this research, design and simulation of an intelligent camouflage using electro-wetting technology have been developed. In this design, an array of optical micro-prisms consisting of a refractory liquid with a changeable shape is employed. By applying electric potential, small volumes of liquids are moved; thus, the angle of breakage of the prisms is controlled for different wavelengths. With objective of covering the surface of the targets, different fluids are used within the micro-prisms and behavior of different wavelengths is studied by writing the optical relations governing the prism output rays and a comparative camouflage pattern is presented.

Visual cameras are among the main systems for recognition and detection of targets. Therefore, in comparison to these systems, camouflage has a very high importance in passive defense. To make effective camouflage in the zone of action, it is necessary to evaluate and analyze camouflage efficiency by suitable methods. Considering the importance of the clothing for military forces, in this study, using visual evaluation of Camouflage method by observers, visual camouflage of three types of operation personnel clothes in north-west area of Iran are evaluated and analyzed, and then an effective and necessary model is provided . This evaluation includes forest clothes, personnel desert clothes and conscripts khaki clothes and uses 16 megapixels canon camera in different distances of 50 to 500m in standing and sitting positions. The results show that from the camouflage aspect, desert clothes have an efficiency of 50% higher than khaki clothes and forest clothes have an efficiency of 100% higher than desert clothes. Also, according to the proposed model for useful and effective camouflage, in the first quarter, the forest clothes and In the second quarter, desert clothes are suitable.

Nowadays cities benefit from two geographical (natural environments, social and economical) and artificial(man-made environments, and architecture)symbols. Mankind has always been trying to change these two symbols for the sake of his daily activities or earning his life and establishing a dwelling both as an interest and as a shelter. During this process green areas, jungles, and gardens have been changed in to skyscrapers and buildings. Replaced for attractive views of nature. Today’s citizens have a sad feeling while they see that they have fallen far from the beauties and quietness of nature.To solve this problem, industrialists have developed the green roof technology. Urban planners and architects use it as ‘back to nature’ process.Green roof is a method to convert the rough, dry, and coldparts of the city in to green spots.Besides green roofs can create micro- climatic zones which reduce pollution and improve the living conditions of the citizens.In this study, the method of "descriptive content analysis" is used, in order to collect information from the Internet and library studies and field methods, such as questionnaires, interviews, and find help, due to the nature of research that is of the type of application, as well as with regard to the issue of research in order to better communication with experts, consider using khi Do(X2)Technique. Application of the results of the use of passive defense operating considerations in green spaces in the city take advantage of herbal elements in Secretion, camouflage and deception plans; the use of green space in designing of urban settlement; To ensachieve these results and decrease the vulnerability and increase the sustainability of the city to achieve multi purposes of passive defense.

The main responsibility of Iran Sea Force (Nedaja) is guarding its Southeastern coasts (Makran).To fulfill this aim, it has developed various infrastructures and also is seeking new ones too. Passive defense is considered as an economicaland cost- effective method in confronting threats. This article tries to explain Nedaja’s passive defense role in developing and maintaining important infrastructures in Makran coasts. This survey, in which viewpoints from different Nedaja professors, commanders, and experts can be found, shows that positioning, camouflage, and fortifications are three main factors that increase the possibility of coastal infrastructures up to 98%. This article has used descriptive and analytic method. Observation, documents, andstatistics (Excel and SPSS) are used to collect and analyse data.

One of the most sustainable measures of passive defense in the strategic domains is to employ buried structures, in particular, tunnels. These tunnels are designed and built in mountain regions with high burms. On the other side, the adversary can take countermeasures to develop their detection methods of these structures. Also increasing the capabilities of their offensive instruments and equipments is their next step.The subject of this study is to investigate, evaluate and model the effectiveness of geophysical detection technologies of buried facilities. Airborne and space based methods are mostly attractive by the adversary. Construction and using these underground spaces, apply different effects on parameters of surface/subsurface of the earth. Using modeling, the Identification capabilities of different geophysical technologies in detecting objects, targets and underground facilities are assessed. In conclusion, the countermeasure methods (Camouflage, Concealment and Deception), have been presented using detection of underground facilities via these technologies.

In regard to the increase in risk of war and aggression in today's world specially Iran's specific position in current time, using principles of passive defense in buildings is inevitable. On the otherhand, every day we are facing problems in the world and our country Iran due to lack of energy. In this article attempts have been made to consider these two important factors, which our country is facing by studying the issue of green view topic. In this regard, walls and green views, are not only important to conserve energy and reduce negative effects of buildings on the environment but they also play a significant role from the perspectives of passive defense and such principles as camouflage, concealment and deception. The information collected in this article is taken from library research methods and valid sources on the Internet. In this regard, at first the principles of passive defense and the buildings that have beendesigned according to these principles, have been studied, then the effects of blast effects and e waves on surroundings were investigated and the results have been collected and analyzed and the assumption of using green wall as a solution for the purpose of reducing energy has been provided and examined. According to the achieved information, green view, in addition to its many benefits in energy debate, has some benefits in the field of passive defense too, such as integration of spaces, shaping buildings, absorbing infrared and, electrical waves and control of blast wave, as well.

This essay is intended to investigate and test the effects of different kinds of smoke on radar wave portion of the electromagnetic spectrum. In regards to the use of electromagnetic waves in the world's current sensors and detectors, the necessity of passive defense and in other words, camouflage against these equipments, is of utmost importance. The use of smoke is one of these ways. Therefore, to perform camouflage, the simulation of a laboratory environment is required which can approximate the smoke camouflage against radar waves as much to the field and operational conditions, as possible. In this essay, a review of the camouflage strength of several material against the radar X- band has been implemented and eventually, taking their reflective coefficient rate into consideration, the carbon fiber as the material which could cause a reduction of 6db in the reflexive coefficient and hence, can be used as a camouflaging material against radar waves.

Metamaterials are artificial composites that acquire their electromagnetic properties from embedded subwavelength metallic structures. In theory, the effective electromagnetic properties of metamaterials at any frequency can be engineered to take on arbitrary values, including those not appearing in nature. As a result, this new class of materials can dramatically add a degree of freedom to the control of electromagnetic waves and open new vistas in military camouflage and offer the possibility of target's perfect cloacking. In this paper, we firstly introduce active and passive metamaterials and then we simulate them with arbitrary shapes.