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El-Sherif A.F.,Laser Photonics Research Group | Harfosh A.,Military Technical Research Institute
Journal of Modern Optics | Year: 2015

A diode-pumped acousto-optic Q-switching Er3+:Yb3+ co-doped high-power fiber laser is reported, laser output average power in excess of 1.65 W was achieved for Q-switching at relatively high repetition rates from 10 to 100 kHz. The shortest pulse duration obtained was 10 ns, giving a highest peak power of 9.8 kW and 98 J energy per pulse, this is the highest power yet reported from any type of actively Q-switched flower double-clad Er3+:Yb3+ fiber laser operating in low order mode at 1550 nm. The pulse train with high pulse-to-pulse stability of 95% occurred at a range of repetition rates up to 100 kHz with peak power of 0.4 kW, 40 ns pulse width and 16 J energy per pulse at 1550 nm for a launched pump power of 5 W. With the mechanical modulation Q-switching of the Er3+:Yb3+ co-doped fiber laser, it was found that the narrowest pulse width of 35 ns was obtained with peak power of 15.5 kW and energy per pulse 0.5 mJ at pulse repetition frequency of 1 kHz. A moderate pulse-to-pulse stability of 75% occurred over a range of high repetition rates. A comparison between mechanical modulation and acousto-optic Q-switching has been made at a repetition rate of 20 kHz. The energy per pulse, pulse width, and the average power of a mechanical optical Q-switching laser were greater than for the acousto-optic Q-switching, but the pulse width is narrower and so the high peak power of an acousto-optic Q-switching pulse is greater than for the mechanical (optical) Q-switching laser at repetition rates of up to 100 kHz. © 2015 © 2015 Taylor & Francis. Source


Valis D.,University of Defence at Brno | Novacek O.,Masaryk University | Chaloupka J.,Military Technical Research Institute
IEEE International Conference on Industrial Engineering and Engineering Management | Year: 2016

In this paper we focus on the estimation of the essential availability and reliability characteristics of super capacitors. The estimation is based on experimental data calculation using a Wiener process. The experimental data were acquired when performing the accelerated tests of super capacitors in the thermal climatic chamber Vötsch VC3 7034. Three thermal levels were used when performing the accelerated tests. Our approach presented in the paper is predominantly not focused on a failure occurrence but on performance durability and availability assessment such as functional stability. We will assess correct functioning and first hitting time if the super capacitor loses its power capacity. © 2015 IEEE. Source


Valis D.,University of Defence at Brno | Zak L.,Brno University of Technology | Chaloupka J.,Military Technical Research Institute
IEEE International Conference on Industrial Engineering and Engineering Management | Year: 2014

The paper deals with application of selected analytical methods for analysing field data from heavy off-road military vehicles. The information from the engine oil are interpreted in form of polluting particles like particles from wear process (e.g. Fe, Pb, Cu, etc.) and particles from oil deterioration itself (like Mn, Si, Zn, etc.). These pieces of information have good technical and analytical potential which has not been explored well yet. There is available reasonable set of vehicles and their oil data from in-field-operation. Based on the data we assume it will be possible to determine some changes in the system. This may help to change e.g. The system maintenance policy, may estimate system operation and help in mission planning. © 2013 IEEE. Source


Valis D.,University of Defence at Brno | Zak L.,Brno University of Technology | Chaloupka J.,Military Technical Research Institute
IEEE International Conference on Industrial Engineering and Engineering Management | Year: 2016

Using the information from oil which is a part of a technical system has been presented a couple of times. The results introduced so far usually dealt with wear metals which get into the oil. However, this paper is based on a different approach. We have assessed Anti-Oxidant and Anti-Wear Particles (AOWP)-oil quality is primarily determined by these particles. These particles are additives in the oil and their amount depends both on operating time and calendar time. In this paper we introduce some mathematical approaches used assess how the number of these particles affects residual useful life (RUL) and maintenance optimizing. © 2015 IEEE. Source


Valis D.,University of Defence at Brno | Zak L.,Brno University of Technology | Chaloupka J.,Military Technical Research Institute
IEEE International Conference on Industrial Engineering and Engineering Management | Year: 2014

The paper deals with the application of selected analytical methods for analysing field data from heavy off-road military vehicles. The information from the engine oil is interpreted in a form of polluting particles like particles from a wear process (e.g. Fe, Pb, Cu, etc.) and particles from oil deterioration itself (like Mn, Si, Zn, etc.). These data have good technical and analytical potential which has not been explored well yet. A reasonable set of vehicles and their oil data from in-field-operation are available. Taking into account data processing we assume it will be possible to determine some changes. This may help to modify e.g. a system maintenance policy, estimate system operation and help with mission planning. © 2014 IEEE. Source

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