Abstract:Safety- and security-related problems for software intensive systems are often due to poor or missing relevant engineering requirements. Although there is nothing really new in our presentation, specified problems and methods are well worth revisiting because they are still far from being widely recognized and put into industrial practice.
Abstract:The paper presents a study on microstructure and microhardness changes obtained in the spun carbon steel tube after shaping by a laser beam. The surface of a pipe was machined circumferentially using a 1500 W CO2 laser beam at various diameters (distance from the focus). As a result, plastic deformations such as convex and narrowing shape changes were observed. The conducted research, including microhardness measurements, shows that, in comparison to the unprocessed material, the microstructure was significantly changed, both in the convex and narrowed layer.
Abstract:This article presents the results of experimental tests and simulations of a light-duty electric vehicle, in which the original lead-acid battery pack was replaced with a lightweight pack of nickel-metal-hydride (NiMH) batteries, which enabled a significant increase to the vehicle’s load capacity. The research was mainly focused on the aspect of electricity consumption and prediction of the range of the vehicle equipped with a new battery pack. The operation of a vehicle with total weights of 500 kg and 740 kg was analysed. Recorded vehicle speed waveforms were used to simulate vehicle motion in the Matlab/Advisor environment. The experiments showed a reduction in the specific energy consumption of a vehicle of lower weight, while simulation tests showed good compliance of the results of electricity consumption with experiments in relation to both the considered total vehicle weights.
Abstract:Composites based on a polypropylene matrix with coffee ground powder, wood flour and tuff of a mass weight of 12.5wt% were produced by the method of injection moulding. Tests of tensile and bending strength properties were carried out and Charpy impact was determined at three temperatures: -24°C, 22°C and 80°C. Scanning electron microscopy (SEM) images were taken to assess the effects of reinforcement and homogenization of mixtures and to determine the characteristics of the microstructure. Composites with 12.5wt% coffee ground powder, wood flour and tuff were characterized by an increase the elastic modulus. Tensile strength slightly decreased for composites with ground coffee grains and tuff.
Abstract:This paper presents IT tools supporting logistics processes. Such processes include, for example, planning the optimal route for the transport of packages or proper packing of these packages in the car. The paper discusses selected computer tools that can be successfully used to improve logistics processes.
Abstract:The laser welding process of test pipe stubs which were made from Super 304 stainless steel is usually used to produce components of a power infrastructure. It was numerically simulated and the obtained results are presented in this paper. For the laser welding method, the weldability of this steel is presented, as well as the results of strength and microstructure tests of a joint welded at the parameter settings selected from a numerical simulation. The chemical composition, including the increased content of alloying elements such as chromium and nickel, improves the strength characteristics of the welded steel, allowing for the production of components of superheaters and partition walls of boilers operating in supercritical parameters.
Abstract:In the analysis of the reactive work of the Alden turbine, two systems of energy recovery were utilized: conical, a straight suction pipe, and a curved diffusor – the so-called bend. The simulations executed on both the systems allowed the operation and selected installation components to be described. Full distribution curves for pressures, velocities were presented, and spectral analyses of pressure fluctuations for the selected points over and under the turbine rotor were also performed. For some structural parts, by means of the FSI – Fluid System Interaction model – the distributions of main stresses and strains according to von Mises theory were illustrated. Additionally, the shapes of deformed installations parts caused by unsymmetrical loads generated mainly by a turbulent water flow were presented.
Abstract:This paper presents the problem of excavation protection in an ‘infill’ construction environment surrounded by neighbouring buildings. It presents a method of protecting deep excavation within a palisade of CFA reinforced piles in casing pipes. The 3D model was built using the ZSoil program, in which the neighbouring buildings were taken into account in modelling. The HSs model of the ground base was adopted. Based on the ITB instruction , an analysis was performed on the impact of building expansion on neighbouring buildings; this analysis provides guidelines for the first two phases, i.e. the phase of shoring construction and the phase of actual excavation. The study also takes into account the phase of building serviceability. After including the results of numerical analysis in the estimation of the displacements of neighbouring structures, the results were compared with indicative displacement limit values of displacement building structures.
Abstract:Two methods of interpolation are presented in this article: interpolation with the help of orthogonal polynomials and interpolation on a cubic spline path (with the help of glued-together functions). Two procedures have been written by the author: WielOrt and Splajn. A comparative analysis of these procedures was conducted by four verification methods that have been created by the author. The examples of verification were chosen so as to make it possible to compare the created by author interpolating function f(x) and the known function g(x). Graphics, numerical procedures and examples were prepared in the Mathematica program.
Abstract:The paper presents results of wind tunnel experiments of wind action on two free-standing lighting protection masts: cantilevered and tripod. Own similarity criteria concerning phenomenon of global stability loss were used in these tests. It was determined whether masts fulfill the requirements of overturning and shift global stability in range of base wind velocities adequate for Poland and different categories of terrain roughness according to the Eurocode . Two possible forms of the loss of the global stability of lighting protection masts in strong wind were considered: overturning a mast and shifting of mast as a whole structures. The measurements were conducted for eight directions of wind attack, five positions of masts on the roof, two settings of the mast for tripod mast and one for cantilevered mast, two categories of terrain roughness. Conducted tests allowed to determine whether it is safe to locate tripod mast in all wind zones in Poland. Cantilevered mast can be located safely in I and II wind zone in Poland.