Browse

101 - 110 of 764 items :

Clear All

Abstract

This paper is a prolegomenon to the research on the history, architecture and state of preservation of the synagogues still surviving in the Podkarpacie region. After almost a millennium of Jewish presence in the area, despite wars and the Holocaust, 31 buildings or the ruins of former synagogues have remained until the present. It can be claimed that a Jewish cultural heritage of considerable value has survived in the Podkarpacie region to this day, and therefore requires protection and revalorisation. The paper presents the state of research in this area and an outline of the Jewish history of Podkarpacie, as well as a preliminary description of the preserved synagogues with regards to their origin, functional layout and state of preservation.

Abstract

This paper presents an experimental method of determining the velocity of chip flow on the rake surface of a cutting insert during the longitudinal turning of Ti-6Al-4V titanium alloy. A Seco CNMG120408-M1 833 carbide cutting insert without a protective coating was used for the purposes of research. In order to record phenomena in the cutting zone, a PHANTOM V5.2 high-speed camera was used and placed above the area of machining. The camera recorded the process at a speed of 3000 fps. Placing the camera near the cutting zone allowed recording the process of chip formation and its flow along the rake face of the insert. Trials of longitudinal turning were performed in accordance with the test plan, where vc and f were the independent variables. In addition, the tests were performed for two different cutting depths. Processing and analysis of the obtained video sequences were performed with the use of CineViewer 663 and Tracker computer applications. Experimental determination of the velocity of chip flow at the rake face of a cutting insert was conducted by analysing the movement of the characteristic point on the outside side of the chip. Analysis of variance for the obtained results was performed using ANOVA and the regression functions were determined.

Abstract

This paper presents the application of failure mode and effects analysis (FMEA) for the risk assessment of changes in the maintenance system of railway vehicles based on the example of the 6Dg type shunting locomotive. The application example is preceded with an introduction to the methodological basis of FMEA, which is specified in literature and standards. In order to ensure the comparability of the analysis results with vehicles of a similar type and to quantify the risk components (the probability of hazard occurrence, the consequences of the occurrence of a hazard and the possibilities of hazard detection) the classification which applies to shunting locomotives was used. Based on the conducted analysis, the possibility to make changes to the maintenance plan for 6Dg locomotives which would not be in breach of the acceptable safety level was demonstrated and preventive safety measures were determined.

Abstract

Infrastructure planning in most cities is a process of sectoral implementation which produces independent sectoral solutions to urbanisation issues. With the advent of sustainable practices, along with the challenges posed by climate change, cities are discovering important synergies among urban infrastructure sectors which are being used to reduce the urban footprint. In the need for sustainable infrastructure, the city of Frankfurt am Main, although operating in a sectoral manner, has learned from past experiences and has progressively developed a collaborative approach to infrastructure planning. This collaborative approach increases the possibilities for trans-sectoral projects and reduces the consumption of natural resources. This paper showcases interesting sectoral and trans-sectoral projects in the infrastructure sectors of energy, water, wastewater, solid waste and urban agriculture. The showcased projects have been selected from a study of 36 operational, programmatic and educational initiatives implemented by the city.

Abstract

In recent years, there has been a trend to reuse abandoned buildings. Adaptive re-use allows preservation of the original structure and implements a new function to it. Suchactivity could help to preserve the historic value of buildings; moreover, many other advantages can be found in educational, ecological and economic fields. However, the question arises of whether every object can be freely adapted. This article examines the case of old prisons which have, for instance, been adapted into hotels and museums. Knowledge of the history of prison architecture as well as experience in preserving and adapting prisons could help to identify the appropriate function for the abandoned penitentiary facilities.

Abstract

The article presents a dynamic model of an electric device supporting the steering system of a passenger car; the model was verified through a series of bench tests. The research object was an integrated electric power steering system (EPS) mounted on a steering column and cooperating with a steering gear. The results of the theoretical analysis were compared with the results of tests performed on a specially built research bench fully reflecting the work of assistance in the car. A satisfactory level of agreement between the results of the model tests and the bench tests was obtained.

Abstract

This article presents the results of laboratory tests involving the measurement of cutting forces during the orthogonal turning of a tube made of GRADE 2 titanium alloy. The nominal diameter of the turned tube was D = 60 mm, and its wall thickness was 2.77 mm. For research purposes, a Kennametal chisel with an insert marked A3G0500M05P04DF and a holder marked A3SAR2520M0425-075-100 was used. An experimental research plan for variable cutting parameters (f, vc) was developed according to the Taguchi method and statistical analysis of the results was performed using an ANOVA. Three series of tests were performed, one for each of the three different values of tube wall thickness (ap = 2.77, 1.77, 0.5 mm). In accordance with the prepared test plan, nine trials were conducted within each series. Cutting forces were measured during each test with the use of a 3-axis Kisler 9257B piezoelectric dynamometer. DynoWare computer software was used for the archiving and analysis of measurement results.

Abstract

The ideas presented by Bernard Rudofsky in the exhibition and book entitled Architecture Without Architects are being proposed by the author as the starting point of discussion on the condition of the architectural profession. Rudofsky focused the world’s attention on architecture formed by the forces of Nature and as a result of natural development processes. The article raises the question of the future of the architectural profession seen from the perspective of the present time, whilst the technological development, in particular automation and computerization of design and construction processes, has gone so far that it is possible in the near future that man might be replaced by machines, which in turn may lead to a deep change in the architectural profession, or to its eventual complete disappearance

Abstract

Light pollution is one of the most widespread but at the same time least noticeable environmental hazards resulting from human activity. It is defined as disturbing the nocturnal environment with light emitted by anthropogenic sources. Light pollution is described as the glare, the trespass, and the sky glow resulting from the scattering of artificial light in the atmosphere. The paper analyses the impact of these three categories on the environment. The results of the long-term research on this problem are presented. It was found that the largest impact on the environment, both direct by the glare and indirect by the sky glow, result from lamps with spherical shields and LED advertising billboards. The possible influence of light pollution on the eutrophication of reservoirs was also researched.

Abstract

This paper presents the wind tunnel investigations of the mean aerodynamic coefficients of the stationary iced model in cable-stayed bridges. The investigations were performed in a Climatic Wind Tunnel Laboratory at the Czech Academy of Sciences in Telč. The icing of the inclined cable model was made experimentally. The shape of the iced model was mapped by a photogrammetry method. The new iced cable model was made by using a 3D printer. The aerodynamic drag, lift and moment coefficients were determined with respect to three principal angles of wind attack within the range of the Reynolds number between 2.5·104 and 13.6·104 at a turbulence intensity of 5 %. It was found that the drag coefficient values of the iced cable model are higher than for a circular smooth cylinder. The obtained results could constitute a basis to formulate a mathematical description of the wind load acting on the iced cables of cable-supported bridges.