D. Kottfer, M. Ferdinandy, L. Kaczmarek, P. Hvizdoš and M. Kuffová
Mechanical and tribological properties of Ti coating deposited by physical vapour deposition (PVD) technique using electron beam to activate evaporation of Ti onto steel OKhN3MFA are evaluated. The thickness and grain growth direction are assessed by means of scanning with an electron microscopy, chemical composition of both the coating and substrate are measured using EDX. The coefficient of friction (COF) and wear was evaluated by a Pin-on-disc test. The wear of the coating was expressed as a loss of material (volume and mass) after the Pin-on-disc test. Hardness and Young’s modulus were found to be from 3.8 GPa to 7.6 GPa and from 65 GPa to 200 GPa, respectively. The measured values of the studied properties were compared with the literature data for Ti PVD coatings.
Keywords: Evaporation, EB PVD, hardness, coefficient of the friction, wear
A. Babu Karuppiah and S. Rajaram
A Wireless Sensor Network (WSN) consists of many sensor nodes with low cost and power capability. The nature of WSN makes it easily prone to security attacks and paves way for attackers to easily eavesdrop the network. One of the deadliest attacks is the packet dropping attack by the intruder where the destruction caused to the network becomes inexplicable. It causes the intruder to lure all the packets and drop which will ultimately disrupt the military functionalities. It becomes essential to detect the attacker in split second before rendering heavy damage to the data and the network. Nodes in a WSN are usually highly energy-constrained and expected to operate for long periods from limited on-board energy reserves and there is a high need for energy-efficient operations. In this paper, a novel algorithm is developed to improve the existing Watchdog monitoring system to detect the false misbehaving node and to eliminate it in short time during surveillance. The existing Watchdog mechanism consumes more energy to compute the Sinkhole node in the network and its trustworthiness also becomes debatable. The simulation results show that exact elimination of the malicious node is done. Moreover, a greater percentage reduction in energy consumption is achieved by the proposed method that makes it more viable for military applications to detect the attacker.
Keywords: Energy efficient mechanism, Military surveillance, Network life time, Sinkhole, Watchdog, Wireless Sensor Networks
V. Horák, L. Do Duc, R. Vítek, S. Beer and Q. H. Mai
The article is focussed on the quasi-dynamic analysis of the air gun performance. The object of modelling is a comprehensive description of the thermodynamic processes taking place in different parts and working chambers of an air gun. Individual equations of the mathematical description are applications of the first law of thermodynamics, which is complemented by the state behaviour and the principles of air flow, including the critical flow. The boundary conditions of the solution of these equations are given by the design dimensions and weights of the gun moving components. The problem is solved using the MATLAB environment. The result of the solution represents the determination of the time courses of pressure in the different working chambers, including the power gas fluid forces acting on the gun moving components and the pellet. Results of the solution are compared with the measured pressure time dependence in the given working chamber and the pellet muzzle velocity of the paintball gun DYE, Proto Rail 2011.
Keywords: Fluid dynamics, airsoft gun, paintball gun, gun performance
M. Sykora, M. Holicky, R. Lenner and P. Maňas
Specification of the target reliability levels is one of key issues required for the assessment of existing structures in emergency and crisis situations. International standards ISO 13822 and ISO 2394 indicate procedures for specification of the target reliability levels by optimisation of the total cost. This approach is applied in conjunction with the human safety criteria to estimate the target reliability levels of existing bridges considering emergency or crisis situations. For the reference period of one week obtained target reliabilities are in most cases within the range from 2.0 up to 3.5, thus significantly lower than those applied in the design of new structures.
Keywords: Emergency situation, failure consequences, human safety, optimization, target reliability
P. Frantis and A. Cuzzolin
The paper deals with development of a simple flight model suitable to be implemented as a C++ algorithm for real-time usage. This model is used for embedded flight simulator in a synthetic vision system. The developed flight model is validated by comparing it longitudinal and lateral responses with typical response modes of an airplane.
Keywords: Simulation, flight model, real-time, programming
The paper describes a procedure of selecting areas potentially suitable for landing of particular formations of helicopters. It describes specific requirements of the NATO documents that have to be respected when selecting the areas for landing. These requirements relate to a slope of ground and an obstruction angle on approach and exit paths. It also lists natural and man-made terrain features that represent the obstacles that can prevent helicopters from landing. Creating the knowledge base and graphical models in ERDAS IMAGINE is then described. The results of modelling different configurations of landing points are presented.
Keywords: ERDAS IMAGINE, helicopter landing sites, knowledge base, spatial modelling
Evaluation of the Effect of Commonly Used Materials on Multipath Propagation of Global Positioning System (GPS) Signals via GPS Simulation
S. Dinesh, S. Shalini, M.A. Zainal Fitry, A. Siti Zainun, A. Siti Robiah, I. Mohd Idris and M.Y. Mohd Hasrol Hisam
In this study, Global Positioning System (GPS) simulation is employed to study the effect of five commonly used materials (aluminium, glass, wood, polyvinyl chloride (PVC) and ceramic) on multipath propagation of GPS signals. Based on the results of this study, it is found that multipath signals from panels made of the materials cause increase in probable error values due to errors in the GPS receiver’s pseudorange measurements. The probable errors decrease with increasing distances of the panels from the GPS receiver due to decrease of strength of multipath signals. It is observed that aluminium causes the highest amount of the multipath, resulting in the highest probable errors. This is followed by glass, ceramic, PVC and wood.
Keywords: Global Positioning System (GPS) simulation, multipath, probable errors, pseudorange measurements, dielectric constant
Downsizing of armies brings the effort to return military premises and facilities back to civilian utilization. Explosive Ordnance Clearance (EOC) is an indispensable phase in the process of decommissioning of exercise ranges. Local authorities, who take over the former military areas, require safe and clean land without any environmental hazard. The left behind ammunition represents the main risk. As a rule, Army is responsible to make any procedures to achieve this requirement. Planning of those procedures is a decisive, even a sensitive factor. Local Authorities insist on the high tempo of clearance process, while units responsible for performing it have to resist of any pressure to speed up their works. This article will bring facts based on the praxis of clearance woks on the former exercise range Milovice, done from 1993 until 2001.
Keywords: Exercise range, Explosive ordnance clearance, ammunition
P. Vyroubal, J. Maxa and T. Kazda
The lithium-ion battery is an ideal candidate for a wide variety of applications due to its high energy/power density and operating voltage. In the military it is used in numerous types of communications and army robotic applications. Lithium-ion batteries are used as a primary and a secondary power source. We focus on the use of secondary power sources. The real lithium ion battery is compared with simulation results and with real measurements.
Keywords: Lithium ion battery, numerical simulation, mathematical model, simulation, measuring
There are many scientists calling robotics for achievement of the modern era. Robotics is a multi-, and interdisciplinary field of the technical and other sciences, based on the newest results of classical-, modern-, and also post-modern control theory. Leaning on tools of modern robotics it is possible enhance manufacturing, improve quality of products. Robots can serve for, and instead of the Man in many dirty-, dull-, and dangerous applications. The goal of the author is to make an attempt to find origin of the word “robot” via historical epochs famous for slavery, free labour, and corvée work.
Keywords: Slave, slavery, serfdom, robot
REVIEW OF THE BOOK
Elementary Flight Dynamics with an Introduction to Bifurcation and Continuation Methods
N. K. Sinha and N. Ananthkrishnan