Abstract:This paper presents the results of experimental studies of the flow resistance of slurry ice flowing through ball valves. Loss coefficients in ball valves were determined from experimental investigations. The study focused on 1/2”, 3/4” and 1” ball valves at two valve positions (20˚ and 30˚). The ice mass fraction in the studied ice slurry ranged between 5% and 30%.
Abstract:This paper reports an analysis of simulated crack propagation in an aluminium sample depending on the direction of external loads. The objective of the study was to perform a numerical analysis of crack propagation as well as to determine regions which are most susceptible to failure. The object of study was created from numerical analysis of material failure due to fibre separation using Abaqus 6.14. The modelling of crack propagation was performed using the numerical xFEM method for separating material fibres irrespective of the finite element mesh.
Abstract:Knowledge of the dynamic properties of a machine tool–holder–workpiece system is crucial for the appropriate selection of machining parameters based on stability lobes. One of the most convenient methods allowing for the experimental identification of these properties is impact testing. However, the repeatability of such measurements may be different depending on the machine–workpiece setup and can lead to incorrect cutting parameter calculations. The article presents this issue on the example of a latheworkpiece system. The experimental setup and obtained measurement results are presented and discussed.
Abstract:In order to obtain the characteristics of a damping force which depends on the amplitude and frequency of the excitation, a modification to the vehicle shock absorber is proposed in this paper. Within the range of small amplitudes, the ‘soft’ characteristics improve riding comfort, while within the resonance ranges, the increased damping force provides a higher level of ride safety. A nonlinear model of the system is introduced, taking into account various strategies of oil-flow control. Utilising numerical integration methods, the influence of excitation parameters and constructional parameters on the characteristics of the damper is investigated.
Kowalska, Maria Elżbieta, Zaczek-Peplinska, Janina
Type: Article
Release date:
2018
Abstract:In the era of the development of modern measurement technologies, their interconnectedness is of high importance. This paper presents a review of the most popular, currently utilised measuring marks in tachymetric measurements and in object laser scanning. This paper presents the authors’ own solutions that facilitate the linkage of data acquired through terrestrial laser scanning with tachymetric measurements. The proposed marks used to perform orientation on the scanned surfaces were successfully tested in the field with the use of laser scanners manufactured by the Z+F, Leica and Riegl companies. The document describes the consecutive steps that eliminate individual problems that arise during both tachymetric measurements and laser scanning. As a result of the work, a new kinds of marks were created allowing tachymetric measurements and laser scanning at the level of accuracy that is required for basic engineering measurements. This paper also presents a discussion on how to prepare the marks yourselves and the marks durability on the surface of the surveyed object.
Abstract:Water supply systems are complex engineering structures; certainly, the most important part is the water distribution network. The design of this element requires calculations and many analyses to arrive at the best solution. The main task of the calculation is to determine the flow rates through pipes, to determine pressure losses, height of tanks, pressure required in the supply pumping station, pressure levels in the individual nodes of the network. Correct execution of the calculations requires careful evaluation of the results obtained and accuracy in the solutions applied. The issue of controlling the results of calculations is difficult to present in algorithmic form as these are mainly based on the experience and knowledge of the designer. Classes of decisions describing the problems of pressure loss in the pipework were established in order to evaluate the results of calculations. Numerical experiments were carried out in this paper to show how the ‘K-nearest neighbour’ method can be used to evaluate pressure loss in water pipes.
Abstract:Contemporary area drainage dimensioning standards are presented in this paper. Hazards for drainage systems arising from climate changes are discussed and trends of changes in the precipitation structure are presented using the example of data obtained from Wrocław. The need for changes within precipitation scenarios is indicated for modelling overflow in channels and a research methodology and assessment criteria of the degree of reliability of the drainage system are proposed. Results are presented of an analysis of the operation of the rainwater drainage system in the Gaj and Tarnogaj housing estates in Wrocław – these were conducted using a calibrated hydrodynamic model in SWMM software. It was proved that the examined system does not meet the standards of PN-EN 752:2008, DWA-A 118:2006 and Merkblatt no. 4.3/3:2009 with regard to instances of flooding from channels and that adaptation to climate change is required.
Abstract:This paper presents characteristics of the Biovac® wastewater treatment plants operating in the mountain areas of the Polish national parks (NP): Tatrzanski NP and Babiogórski NP as well as in the West Spitsbergen NP. On the basis of the laboratory tests performed on raw sewage and the final effluent the efficiency of the wastewater treatment plants was evaluated. It was found that high COD values and rather high COD / BOD5 ratios were observed in the raw sewage during an off-peak tourist season. The research has also shown that the Biovac® treatment plants (SBR technology) showed a high level of removal of pollutants from sewage discharged from mountain hostels.
Abstract:This article describes a new ant colony optimisation algorithm for the facility localisation problem with a new heuristic pattern proposed by the author, which consists of three parts: the function of the average cost of client servicing; the total minimum cost of servicing from a site, which is selected and included into the solution; the function of improving the cost of already serviced clients. In this comparison, simulations were presented, and two parameters were observed: the number of sites and the cost of client servicing. The new algorithm allowed to improve the solution in both of these parameters.
Abstract:The technology of erecting war shelters has been evolving over the centuries alongside the development of technology and building-oriented requirements. Many papers have been published on this subject in recent times. The ruins of the Wolf ’s Lair war fortress prompted the authors to write this work with a slightly different emphasis than the previous papers. In addition to a brief history of the objects, the work presents the design guidelines used in their construction and describes the construction solutions applied. In addition, where appropriate, the advantages and disadvantages of these construction solutions from an engineering point of view are highlighted.
