When coalition forces realize enemy’s intention to make use of the underground space for his belligerence, they must predict all options how to make military facilities less vulnerable from below. The article is focused on the simple geotechnical situation: Tunnel of 1m diameter, excavated by handy tools in loose materials, like sands or gravel. Further, the stability of the unsupported tunnel and effect of mining support is considered. Finally, which depth is presumable, when improvised tunnel should be done and profile reinforcement should be omitted. The best way how to explain it is to recognize the basic rules of the underground excavations stability. We cannot suppose drifting in the solid rocks. On the contrary, the clandestine excavations could to be achieved in loose materials, where silent technique, like shovels or pickaxe can be applied. The article would like to put the reader’s mind to geotechnical features that can facilitate or hamper the enemy’s effort to undermine coalition forces facility.
Keywords: Underground Drifts, Excavations, Undermine, Stress-Strain Status
Shock-less Transmission in the Breech Mechanism of a Weapon with Bound-Together Barrels and Breeches
The weapon with bound-together barrels and breeches is one of three used high rate of fire weapon principles. A very important task of the designing this weapon is to ensure the shock-less function of its mechanism. This is solved by the convenient choice of the transmission function of this mechanism. On the base of this transmission function it is possible to design the functional curve which ensures the required shock-less motion of the breech block driven by the carrier by means of the crank mechanism placed between the carrier and the breech block.
Keywords: Shock-less transmission, breech mechanism, crank mechanism, functional curve
J. Hub, J. Komenda and M. Novák
The article describes the method of determination of limit velocity for the aluminium alloy sheet metal from the airplane fuselage skin hit by a pistol projectile of calibre 9 mm with utilisation of 2D FEM model of interaction between the projectile and the sheet metal. The simulations are based on accomplished firing experiments and results are compared. The results of simulation can be utilised for prediction of level of damage of aircraft fuselage in case of firing on board of the plane.
Keywords: Aluminium alloy 2024-T3, pistol ammunition, 9mm Luger bullet, penetration, ballistic limit, FEM
L. Jedlicka, J. Komenda and S. Beer
The article deals with the ballistic analysis of pistol cartridge of calibre 9 mm Luger. As a basis of the analysis the standard cartridge with 8 g FMJ projectile was chosen. The aim of the analysis is to assess the effect of projectile mass change on basic ballistic characteristic of weapon-cartridge system during development of new types of projectiles. There is also explained possible utilisation of the obtained results with use of selected typical small arms cartridge in the end of the article.
Keywords: Ballistics, design of ammunition, small arms cartridge, ballistic analysis
I. Hamtil and J. Farlik
One subsystem of the Czech GBAD system 2K12 which is currently being modernized is the automated 1A18 device for missile aiming and positive target-in-zone indication. Its contemporary construction is according to the mid-20th century technology. The device is an analogue electro-mechanical computer which does not meet today’s needs of reliability and operational demand factor. This paper concisely deals with a possibility of this device replacement by a more universal digital computing device. Here, the definition of tasks solved by starting device, its mathematical formulation, solution strategy and verification results through MATLAB simulation are stated.
Keywords: 1A18 device, SA-6, modernization
Z. Matěj, J. Cvachovec, F. Cvachovec and V. Přenosil
This paper shows the results of digital processing of output pulses from combined photon-neutron detector using a commercially available ACQUIRIS DP 210 digitizer. The advantage of digital processing is reduction of the apparatus in weight and size, acceleration of measurement, and increased capability to handle pile-up of pulses. The neutron and photon spectrum of radionuclide source 252Cf is presented.
Keywords: Two-parameter spectrometer, digitization, stilbene, pulse shape discrimination
B. Plihal, J. Komenda, L. Jedlicka, S. Beer and R. Vitek
This article deals with an analysis of the resistance against projectile penetration and bending of ballistic protection vest made of a ballistic textile. A mechanical model of the core of ballistic protection vest is designed, theoretically solved, and experimentally verified. The stiffness characteristics of the ballistic protection vest core were obtained from the technical test utilising a free fall weight. These characteristics allow a prediction of a chosen small calibre projectile movement in the same material during a firing experiment. The shape deformation of ballistic protection vest core layers is analytically expressed by their bending in the direction of the projectile movement.
Keywords: Terminal ballistics, ballistic protection vest, mechanical model, small arms
J. Čižmár and J. Němeček
The paper deals with the influence of control system of a mobile free-space optical (FSO) link on the power budget of the link. Permissible fluctuations of the received power are taken into consideration. It is assumed that these fluctuations are caused by oscillations of the optical beam across the receiver aperture. The design, operation and transfer functions of the control system of the optical axes position are described.
Keywords: Free space optical link, power budget, steady model, control system, global positioning system, inertial reference unit, video camera, transfer function
Acetylcholinesterase Based Colorimetric Dipsticks for Military Performance: Principles and Construction
M. Pohanka, V. Vlček, J. Žďárová-Karasová, K. Kuča, J. Cabal and J. Fusek
Colorimetric dipsticks based on recognition capability of acetylcholinesterase enzyme (AChE) are a suitable tool for a fast and sensitive detection of nerve agents and some pesticides. In this review, the detectors are digestedly presented and basic biochemical methods appropriate for the colorimetric estimation of AChE enzymatic activity are included as well. Moreover, the available matrices suitable for construction of dipsticks and chemical, as well as physical protocols for AChE immobilization on detectors surface are introduced.
Keywords: Colorimetry, nerve agents, acetylcholinesterase, dipstick, detector
Workplace for Performance Testing of Energy Accumulators for Electric Devices
J. Sadil and M. Leso
For electric devices with critical requirements on energy, performance parameters and characteristics of their accumulators are very important and desirable to know. Automated workplace within the Department of Control and Telematics, Faculty of Transportation Sciences at Czech Technical University in Prague (CTU FTS) established in 2010 is able to perform both short-term and long-term testing of electric accumulators performance. The workplace is introduced in Chapter 2, Chapter 3 presents HW and SW solution of the workplace and an example of results for LiFeYPO4 accumulator is finally shown in chapter 4.
Keywords: Energy accumulators, electrical measurement, automation, automated measurement, education, long-term testing