The article demonstrates the design process of a flux compression generator. Several armature configurations and materials have been analyzed. The influence of mechanical parameters, such as wall thickness, inner diameter of the armature or high explosive material used, on FCG performance has been estimated. The geometry of generators’ components has been optimized using the Finite Elements Method. Several generators have been built based on mathematical model and simulation results. The designed FCG’s performance has been verified during field tests. A comparison of simulation and field test results has been presented.
Cement is a common and widespread building material over the world. Similarly, carbon dioxide emissions have been significantly increased due to cement production. Alternative low-carbon binders rather than cement have been progressively sought in recent years. Fly ash was found as an available option, since it is being largely disposed annually as a waste material. In this research several studies have been reviewed and recent applications of fly ash on concrete specification, including strength and fracture toughness of green concrete have been perused. Furthermore, transport properties of high volume fly ash after exposure to high temperature and influence of curing temperature on strength development of fly ash-recycled concrete aggregate blends have been investigated. The investigated test results showed that the properties of composites incorporating fly ash depend on the age of the concrete. Test results also revealed that transport properties of concrete increased notably after exposure to 400cº and the results achieved on fly ash-recycled concrete aggregate led to the conclusion that 15% FA is the optimum blend for road stabilization applications.
The need to confirm compliance with the requirements of the Polish Defence Standards, STANAGs and shipping classification societies documents poses new challenges for manufacturers and suppliers of ship’s equipment and systems. This is related to the continuous technical evolution of electronic and electrotechnical devices, especially in the field of wireless transmission and data exchange. These challenges also apply to research laboratories, which must keep up with both the technological changes of the examined objects and the updating of requirements and reference documents. It is connected with the necessity of constant development in the area of technical facilities and competences. This paper presents an overview of the currently binding requirements for devices and systems for newly built vessels, with particular regard on the area of electromagnetic compatibility. It indicates the planned trends of changes of these requirements in relation to the technical evolution of devices. Discussion with several examples of problems and challenges faced by both equipment suppliers and research laboratories engineers were presented.
Although various analytical and numerical methods have been proposed by researchers to solve equations, but use of numerical tools with low volume calculations and high accuracy instead of other numerical methods with high volume calculations is inevitable in the analysis of engineering equations. In this paper, B-Spline spectral method was used to study buckling equations of the piles. Results were compared with the calculated amounts of the exact solution and finite element method. Uniform horizontal reaction coefficient has been used in most of proposed methods for analyzing buckling of the pile on elastic base. In reality, soil horizontal reaction coefficient is nonlinear along the pile. So, in this research by using B-Spline method, buckling equation of the pile with nonlinear horizontal reaction coefficient of the soil was investigated. It is worth mentioning that B-Spline method had not been used for buckling of the pile.
Dams are considered as strategic structures due to their initial role in economic system of the country, therefore, they are expected to be fully functional and powerful. Nano technology could be an effective factor of abrasion and compressive strength, porosity and hydraulic conductivity coefficient of the concrete, thus more scientific research is essential to be carried out on these types of concrete due to their quite modern and high technology. In the current study, the effects of water-cement ratio on compressive and abrasion strength, porosity and hydraulic conductivity coefficient of concrete was investigated. The constructed concrete samples with 4% Nano-silica and water-cement ratios of 0.35 to 0.55 were tested. Other design features remained fixed in all concrete samples. The compressive strength of block samples of 150×150×150 mm were assessed in terms of time lasting 7, 28 and 90 days. The abrasion strength of the identical block samples were tested after 28 days. The hydraulic conductivity coefficient of cylindrical shape samples with the diameter 150 mm and height of 300 mm were experimented after 28 days. The results of the experiments indicated that by reducing the water-cement ratio from 0.55 to 0.35, the compressive strength increased 37.13, 40.14 and 38.22% for 7, 28 and 90 days age samples respectively and abrasion strength of concrete increased 38.22% and the hydraulic conductivity coefficient (m/s) and depth of penetration (mm) of the concrete decreased from 27.76×10−15 and 2.756 to 1.5×10−15 and 0.784 respectively. In addition porosity decreased from 12.76 to 11.22%.
The article presents the analysis of the threats to Polish Navy ships resulting from the development by the Baltic Sea countries of missile systems or turbojet missiles. The most popular varieties and types of missiles that could be used against Polish Navy vessels were described and classified taking into account mainly the potential of the Baltic Fleet of the Russian Federation (BF FR), as well as an analysis of the latest global trends in the area of counteracting these missiles. The article presents the conclusions drawn from exemplary simulations of the attack of modern anti-ship missiles. The article also contains references to the ways of determining the probability of avoiding a rocket attack and the measure of the effectiveness of self-defence of attacked ships. The work contains conclusions regarding desirable traits from the systems of self-defence of ships on the modern battlefield with particular emphasis on the character of the Polish Navy. The article presents an analysis of the threats to ships of the Polish Navy, resulting from the development in the Baltic Sea countries, missile/turbojet anti-ship systems. Were described and classified most popular varieties and types of missiles applicable to fight Polish Navy ships and described latest global trends counteracted against these missiles. The article presents the conclusions drawn from exemplary simulations of the attack of modern anti-ship missiles. The article also contains references to the ways of determining the probability of avoiding a rocket attack and the measure of the effectiveness of self-defence of attacked ships. The work contains conclusions regarding desirable traits from the systems of self-defence of ships on the modern battlefield, with particular emphasis on the nature of the Polish Navy.
The VOLTA project is a RISE Marie-Curie action designed to realize Research & Innovation (R&I) among intersectoral partners to exchange knowledge, methods and workflows in the geospatial field. To accomplish its objectives, the main R&I activities of VOLTA are divided in four interlinked Work Packages with two transversal ones responsible for knowledge transfer & training as well as dissemination of the project results. The research activities and knowledge transfer are performed with a series of secondments between partners. The consortium is composed of 13 partners from academic & research institutions, industrial partners and national mapping agencies. The Romanian National Center of Cartography is part of this research project and in this article the achievements of the secondment at Bruno Kessler Foundation in Trento (Italy) are given. The main goal of the exchange was to generate level of detail - LOD2 building models in an automated manner from photogrammetric point clouds and without any ancillary data. To benchmark existing commercial solutions for the realization of LOD2 building models, we tested Building Reconstruction. This program generates LOD2 models starting from building footprints, digital terrain model (DTM) and digital surface model (DSM). The presented work examined a research and a commercial-based approach to reconstruct LOD2 building models from point clouds. The full paper will report all technical details of the work with insight analyses and comparisons.
The article presents comprehensive documentation of the situation of post-mining Miedzianka village (former town), which is located in Lower Silesia, in south-western Poland. Due to the long-term expansive mining exploitation since the 14th century, over time Miedzianka was completely destroyed and depopulated, thus nowadays, only a few inhabitants live there. The basis for the conducted research area were changes in land and urban structure that have been occurring for centuries in connection with mining operation of copper and uranium. The authors focused on presenting the changes using archival cartographic documentation, land surveying measurements and 3D modelling. That data allowed to determine on the ground specific sites related to mining operations, discover old urban buildings, performing their 3D models and finding places potentially threatened by continuous and discontinuous deformations. The combination of all the data allowed to present the full situation that occurred in Miedzianka.
The paper presents the dynamic positioning system (DP), particularly its thruster allocation model, designed for ORP ‘Kormoran’, a Polish mine destroyer built for the Polish Navy in Remontowa Shipbuilding S.A. in Gdańsk. The ORP ‘Kormoran’ ship is the newest and best equipped minehunter ship in Europe. The main task of the new Polish mine destroyer is to search for, classify, identify and combat marine mines and improvised underwater explosives, recognize waterways, transport mines, deploy mines and provide remote control of self-propelled anti-mine platforms. The dynamic positioning control system of the ship presented in the article was constructed by Autocomp Management Ltd. from Szczecin, the only in Poland and one of the few producers of dynamic ship positioning systems in the world.
Passive defense systems which minimize chance of vessel detection have to be utilized due to application of naval mines. Passive defense and signature minimization can be regarded as not only magnitude reduction but also as its shaping. Electric field magnitude at a given depth is a function of an electric field source but also it depends on physicochemical properties of seawater — temperature and salinity. In this paper results of underwater electric field simulations are presented. Cases of various depths, temperatures and salinities are shown. Computational results are compared to underwater electric field measurements performed with portable sensor.