AiMT Volume 6 (2011), Issue 2

Modelling of Ball Impacts on Coatings and Erosion of Special Technique Components

J. Stodola

Special military ground vehicle operate in extreme conditions and require extensive measurements to improve the durability of all systems and materials in their subsystems. Protective coatings usually perform this function with great success. One of the most pressing needs for special vehicle is the development of high performing coatings for erosion protection of engine components (turbine, compressor, turbocharger, intercooler components, etc.). The approach presented in this paper is based on use of computer simulation techniques to model coating behaviour in simulated erosion conditions. Shear stress and equivalent plastic strain at the coating substrate interference were used as criteria describing coating response to particle impact. This article deals with preliminary modelling results, in terms of selecting range of material properties (internal layers thickness and stress or strain) and coating structure.

Keywords: Wear, erosion, coating, impact, hardness, modelling

Pages: 5-18

A Simple Spectrophotometric Determination of Cyanides by P-nitrobenzaldehyde and Tetrazolium Blue

V. Pitschmann, Z. Kobliha and I. Tušarová

The article describes a simple and a very sensitive spectrophotometric method for determining free cyanides, based on their catalytic reaction with p-nitrobenzaldehyde. Cyanide ions allow for a transformation of p-nitrobenzaldehyde into its transitory reactive cyanohydrin, which reduces a redox indicator, the tetrazolium blue, into a purple-coloured diformazan derivative. The product’s absorption maximum is 520 nm, the determination limit found by calculation is 0.005 mg·l–1 and molar absorptivity is 4.86 × 105 l·mol–1·cm–1. Determination is obstructed by the presence of strong reductive substances.

Keywords: Spectrophotometry, cyanides, p-nitrobenzaldehyde, tetrazolium blue

Pages: 19-27

Additional Effect of Gases on Strain Gauges at Barrel Muzzle

S. Procházka, P. Seman and M. Vondráček

The paper deals with the analysis and measurement of stress and strain of the barrel when the projectile goes through the muzzle. A muzzle of the barrel is stressed in a special way. This fact can influence the accuracy of firearm performance. The paper describes the issues of measurement; precisely an adverse influence impacting the strain gauges which takes place in the nearness of firearm muzzle of the experimental barrel, calibre 30 mm. The development of the experiment is presented. The amount of deformation, as well as the value of pressure at the muzzle will be checked by means of the quasi-static dynamics conditions that are described in this paper.

Keywords: Firearm barrel, barrel muzzle, strain gauge, piezoelectric sensor, gas pressure, barrel strain

Pages: 29-38

Military Prediction of Incursion from Underground

P. Beyr

Asymmetric and underground warfare are of very tight relation. The absolute superiority of the coalition forces on the ground and air makes the underground space an additional tricky battlefield. The risk to be buried in the improvised tunnels or shafts is high but acceptable for the enemy, whose survivability on the surface is low. When enemy decides to make use of the underground space for his benefit, the coalition forces have to predict the location of underground openings. There are existing and recently excavated drifts. The first ones could be created by nature or dug by people. The enemy can utilize them as dugouts, assembly or logistic points. The recently excavated drifts could be utilized by the same way or offensively. Cave outlets could be used as firing points. No coalition facility can be safe against undermining. The article would like to explain the geotechnical conditions that can facilitate or hamper the enemy’s effort to make use of the underground space.

Keywords: Underground Drifts, Caves, Undermine, Perimeter Security

Pages: 39-46

Design of a Dynamic Allocation of Frequency Channels to Services in CATV Networks

J. Hlubik and L. Schwartz

This paper deals with a model of the intelligent interactive CATV network design. Function of this model is described as the Markov process. The design of the frequency band segmentation of a coaxial cable and new network elements are shortly described in the introduction. The frequency band segments are studied analytically while the network traffic is simulated by network simulation model. The analytical solution and simulation on real data are discussed in the conclusion.

Keywords: CATV, HFC network, Queuing theory, Kolmogorov theorem, mathematical model, simulation model

Pages: 47-54

Radio Signal Source Position from Measured Azimuths

A. Hofmann, V. Kratochvíl, V. Talhofer and Š. Hošková-Mayerová

The determination of moving object position is quite frequent task of armed forces. There are several techniques which use active or passive systems. The passive systems are based on capture, identification and analysis of any radio signal emitted by fast moving object (airplane, rocket etc.). The position of object can be determinate from this information. One possibility how to determinate the object position is a usage the measured geodetic azimuths of the moving object from several mobile devices (initial points). The principles of spherical trigonometry and geodesy are applied. The employed solution comprises the following key steps: calculation of azimuths and the connecting line of the initial points, calculation of unknown distances to the target, determination of geographic coordinates of the target, transformation of geographic coordinates into planar right-angled ones in the projected coordinate system. The above described technique was tested in the area of the Europe and final results and position differences were evaluated. Several recommendations for effective usage of described technique were done with respect of results of passed tests.

Keywords: Target position determination, direct/inverse geodetic problem, chord method, numerical integration, radio direction finder

Pages: 55-67

Expedient Repairs – Analysis of Possibilities and Needs

T. Smal and J. Furch

The article presents organizational and technical conditions connected with the implementation of the system of military equipment expedient repairs (ER) for military technical support’s functioning. Furthermore, the article mentions such issues as unification and adjusting the equipment in a design and production processes, pro-active diagnostics, procedural conditionings, training, technology and temporary repair. Each issue is discussed considering possibilities and needs of expedient repairs system implementation.

Keywords: Logistics, operation system, field repairs of the military equipment, telemetry maintenance system, temporary repair

Pages: 69-82

Emergency Support System: Actionable Real-time Intelligence with Fusion Capabilities and Cartographic Displays

T. Řezník, B. Horáková and D. Janiurek

This paper describes the Emergency Support System (ESS), which is an FP7 European Project (funded from 2009 to 2013), as well as a suite of real-time (spatial) data-centric technologies, which will provide actionable information to crisis managers during abnormal events. The approach guiding the ESS project and architecture is based on the fusion of variable forms of field-derived data, including data obtained from unmanned aerial vehicles (UAV), unmanned ground stations (UGS), air balloons and cell-phone trackers (IMSI catcher), as well as on data obtained from external Web services (supplying mostly spatial data and functionality based on spatial data) and external crisis management systems (e.g. command and control systems). Fused data are visualized on the ESS portal.

Keywords: Data fusion, Sensor Web Enablement, Cell-phone detection, Cartographic visualization, Crisis management

Pages: 83-97

Bi-modular Charge System for Calibre 155 mm I.

J. Beránek, L. Lehký and M. Hrdlička

The article provides background information on issues of Bi-modular charge system designed for 155 mm-calibre weapon system. It summarizes the principles of design and knowledge gained during the development stage, and provides information about firing of modules in the testing cannon.

Keywords: Bi modular charge, interior-ballistics, cartridge chamber, 155mm calibre, propelling charges

Pages: 99-107

The Key Role of the European Defence Agency in the Enhancement of European Defence Research and Technology

I. Koblen and F. Olejník

The paper in the introductory part underlines the importance of the defence research and technology (R&T) as a decisive factor of the defence capabilities development and strategic pillar of the Armed Forces transformation. Authors inform on functions and tasks of the European Defence Agency (EDA) in R&T area in accordance with the Joint Action and consolidated version of the Treaty on European Union, as it results from the amendments introduced by the Treaty of Lisbon. The authors are focusing on the explanation of the Capabilities Technology (CapTech) as a basis for both generation of cooperation projects and network of experts (Governmental and non-Governmental) in the R&T area and the key operating rules specified in R&T Operational Concept. The information on EDA defence R&T projects categories are also introduced. The part of paper is dealing with European Defence Research and Technology Strategy as a principal strategic document (aim of this document and main considerations). The authors inform on the technology priorities in the EDA framework. The last part of paper is focused on selected challenges in the European R&T area.

Keywords: Defence Research and Technology (R&T), European Defence Agency, Capabilities Technology, cooperation, programmes, projects

Pages: 111-122