Volume 115 (2018): Issue 11 (November 2018)

Global climate change is a problem which arises numerous theories and uncertainties, especially in terms of speculated human impact. Independent from the fact, what is the main driver for the changes, some of the climate shifts are visible already nowadays. Both contemporary and future cities will have to face such problems. Although climate change may cause numerous effects on different fields, a special stress in this article is laid on hydrological events – which are possible to observe even in these days. The purpose of this article is to indicate the main approaches both to the issue of climate change and activities undertaken by cities in relation to hydrological threats.

We propose a historical architectural study of the hypogeum of the church of Sant’Andrea in Akko (Israel), which promoted new reflections on the urban historical fabric and at the same time provided concrete data for a redesign of part of the structure in line with the historical role and the building Hierarchy that made it a cornerstone for navigation and orientation at sea. The discovery of its architectural composition led the design to an extended dimension in addition to the building itself. We intend to propose a violation of contemporary architecture as a daughter of history and not as an assertion of modernity often detached from the context. In this case we try to recover the role and monumentality of the building, the urban context and the sea front.

This paper presents an outline of the history of spatial transformations of Cracow’s largest suburb in the years 1587–1655. So far, this topic has not been given due attention and the published works only present the history of Garbary up to the invasion of Archduke Maximilian Habsburg in 1587. However, the siege of Cracow by supporters of the representative of the House of Habsburg, who aspired to the throne, closed an extremely successful stage in the history of the suburb, and the liquidation of existing buildings forced its residents to undertake a quick and intensive reconstruction. Furthermore, the paper contributes to further research into the suburb’s development at the end of the 16^th century and in the first half of the 17^th century, thus filling a considerable gap in research on the development of the urban system of Cracow.

Modern stadiums constitute a challenge to urban planning, architects and buildings. The exceptional character of these enormous structures is, on the one hand, highlighted by their unique massings and the innovative materials that they employ, while on the other, their composition within the space of the city and its skilful blending into its context causes them to become icons and landmarks. Three different examples demonstrate that the requirements presented above can be fulfilled. Modern forms have been fitted into the scale of cities of various size and adapted to their surroundings. Functional solutions were well-thought out and circulation and access have been placed so that events would not block traffic in the city each time they are held.

The dynamic development of health resorts is cause for the comparison of the tendencies in the changes observed in terms of the development and arrangement of the space in therapeutic complexes and their adjacent localities. Studies demonstrated differences both in the programme of these complexes, as well as in their formal solutions.There are the result of civilizational differences, conditions of the natural environment or of the state of affluence of citizens. there can constitute an inspiration for the development of Polish layouts of spa, In conditions of competitive development, the increase in the wealth of society and the care for health and good physical fitness, the fully justified are improvment of standards quality of public spaces and increasing the amount of green areas.

The paper presents a way of taking account of the effect of changing loads on the deflection of RC beams reinforced with ribbed bars. The proposed solutions were verified experimentally, based on the results of tests performed by the author. The beams were subjected to multiple repeatable loads. The deflection increment dependent on the value of the basic parameters characterising the changing loads (cycle maximum load M_max, stress ratio R, number of load cycles N_i). The increment of the deflection of RC beams reinforced with ribbed bars subjected to changing loads increases with increases in the number of load cycles N_i (logN_i, to be more accurate), and is greater for higher values of ratio k and lower values of ratio R (k = M_max/M_n; R = M_min/M_max; M_min – minimal moment of cycle; M_max – maximal moment of cycle; M_n – failure moment under short-term loads). The relations for the number of load cycles N_i are similar.

A comparative study of the load-bearing capacity of selected steel plate girders with slender webs under fire action is presented in this paper. Typical plate girders and girders with corrugated webs are considered. Stiffeners are only placed at the ends of cantilever beams so the shear buckling is a possibility. Fire resistance of the analysed members was estimated using two separate FEM software packages. Moreover, the computational approach applied for each case was different, thus validation of the software was possible. Failure modes, critical temperatures and deformations for steel plate girders subject to fire temperatures are also presented.

The requirements relating to the emission of auxiliary AC supply sockets in traction vehicles have been extended in standard PN-EN 50121-3-2:2015 by voltage harmonics measurement. This applies to the public on-board AC supply grid which is accessible to all passengers. It is concerned with providing the quality of power supply which is required by computer devices and mobile phone rechargers. This article presents the requirements and test methods resulting from extended standard scope. Normative factors, for which levels of permissible voltage harmonics in the public supply grid of traction vehicle have been defined are discussed. Examples of comparative results obtained from measurements and analyses of voltage harmonics within on-board supply grids are also presented. The presented results include extended calculations of distortion factors for groups and subgroups of supply voltage harmonics. In order to improve the quality of voltage within the on-board grid, which did not meet the requirements, simulation calculations were performed and an additional output sinusoidal filter was proposed.

This paper presents further results of research on the load variability of rectifier units for the selected tram traction substation. Actual measurements were used in the performed analysis. This time, the analysis was focused on the characteristics of maximum loads and overloads for time periods of five minutes and sixty minutes, for a number of selected cases. The second part of the article discusses the effectiveness of the use of artificial neural networks of the feedforward type with one hidden layer with eight neurons to analyse the overloads of the traction substation over a longer time scale. The obtained positive results indicate that this type of research should be continued, using different variants of artificial neural networks.

The first part of this paper presents a comparison of the measured and simulated results of the load variability of rectifier units of a tram traction substation. The subject of the tests was a power supply substation for the contact line of a tramway, the profile and traffic of which was known. After a positive appraisal of the applied simulation method, an assessment of the range of load variability for the rectifier units took place for a hypothetical situation involving the concentrated disposition (layout) of the traction substations (so-called micro-substations). The results acquired under the described circumstances are presented in the second part of this paper.

The authors propose a supplementary method for modelling seepage flow around a deep drilled well screen. The study applies 3D numerical modelling (FEM) in order to provide an in-depth analysis of the seepage process. The analysis of flow parameters (flux distribution q(x, t) and pressure distribution p) was conducted using the ZSoil.PC software system. The analysis indicates that the shape of perforation is of secondary importance during deep bore well screen selection.

The paper investigates and compares a selected issue of Serviceability Limit State (SLS) of simply supported reinforced concrete (RC) beams subjected to various values of flexural stresses. Characteristic crack widths of beams reinforced with various types of bars were calculated. Beams reinforced with Glass Fiber Reinforced Polymer (GFRP), Carbon Fiber Reinforced Polymer (CFRP) and Aramid Fiber Reinforced Polymer (AFRP) were examined. The computational analysis of beams reinforced with FRP bars was based on Italian guideline for the design (CNR-DT 203/2006) and in accordance with the EC2 (EN 1992-1-1:2004). Based on the conducted analysis, the effect of changing the service live load on the increase in crack width was presented.

The paper presents a design, working principle and simulation of a sensorless position system whose hydraulic linear stepper actuator is controlled by a combination of single binary on/off valves. For dynamic modelling and digital simulation of stepper actuator, the bond graph method was used. Preliminary simulation tests were conducted to determine the dynamic characteristics and dynamic properties of the stepper actuator.

Increasingly, many conventional and advanced automotive coatings applications demand materials with well-defined surface properties, fulfilling specific requirements and affecting automotive industrial development. The main assumption for the study was to analyze the microstructure and adhesion of epoxy powder coating on a steel substrate. The results of optical microscope metallographic, SEM/EDX, XRD analysis and adhesion test are presented.

The paper presents the results of mechanical properties research of samples made in the Selective Laser Sintering technology. Polyamide powder PA 3200 GF reinforced with glass fiber was the material used to build the model. Samples subjected to a uniaxial tensile test were made in accordance with ASTM D638 – V standard. The printing direction was the technological parameter of the study. The analysis of the results showed that the addition of fiberglass significantly influenced the improvement of mechanical properties, especially the isotropic of mechanical properties with respect to the printing direction.

The subject of this paper concerns the search for structural solutions of pneumatic cushions [1, 2] in order to minimize the air consumption, operate at the lowest admissible pressure and compensate for the unevenness of the floor. The paper presents the solution with a multi-nozzle air outflow. This solution was obtained by a theoretical analysis, then a prototype of the device was made and laboratory tests were carried out.