Volumen 115 (2018): Heft 10 (October 2018)

The development of organized green areas in the specific circumstances of New York’s “culture of concentration” [1, p. 10] takes place, among others, in areas whose original function has changed or found a new peripheral location. Many projects related to transport, storage, or freight forwarding have been completed in post-industrial areas. The issue of rban space recycling, besides the basic question of adapting the area to a new function, requires a particular reference to the cultural heritage of the place, including its material legacy, which is sometimes difficult to preserve and expose. This article presents characteristic examples of urban recycling in particular districts of New York where the new function of a city park has been overlaid on unused areas, while preserving their characteristic environmental circumstances and cultural identities.

The author analyses selected examples of contemporary built residential development projects in locations close to the historical city centre of Wrocław that create a new architectural frame around the waterfronts of the Oder River. The ambitious works of architecture, constituting a contemporary interpretation of the atmosphere and tradition of the place, introduce new values into the unique space of the waterfronts, remaining in accord with the new philosophy of cultural heritage.

The paper is devoted to the renewal of inner city districts, burdened with a difficult identity. The analysis focuses on the case study of the district of Hulme in Manchester. Within the perimeter of Hulme the attempts to revitalise the area burdened with bad reputation of the biggest slum in Manchester have been made twice. The paper presents the genesis of the bad reputation of the district, its effect on the degradation of the district, as well as it describes the strategies undertaken during both attempts of the revitalisation of Hulme.

700 years of the former royal palace in Lobzow’s history is a period of reconstruction and adaptation. Time faded traces of a representative residence and the nineteenth century brought her down. Reconstruction for the Austrian Kadetten Institut replaced the charming ruin with the barracks. Sources regarding the history of Krakow’s Officer Cadet School are very diverse and largely unrecognized. They cover both the architectural object and the entire town where it was located. They concern its ownership status, topography of the area, natural properties and urban values in relation to the capital city of Krakow. The author of this article attempted to characterize the transformation of the royal palace in Lobzow over the centuries, based on an analysis of its state of research.

In modern computer networks, agent-based systems are widely used. The very fundamental usage of agents are for management systems e.g. supporting SNMP-based databases and multiple client-server communications. This paper describes the Pay&Require mechanism implementing a multi-agent approach for a QoS-enabled computer network. The unique features of the P&R system are its comprehensive approach to the cooperation of agents dedicated to traffic monitoring, the selective response to the QoS-oriented admission of user requests, event-driven reconfiguration and transmission quality brokerage. The brokerage in quality purchase was based on different models – from a simple reactive agent to an agent with learning capabilities. The presented approach uses auctions in which agents (brokers) can buy quality parameters according to customer requirements. The use of auctions allows the dynamic pricing of data transmission services.

Electric multiple units (EMUs) EN57 are fitted with two cage induction motors to each bogie. Two motors driving one bogie are supplied from a common DC/AC inverter. These motors become damaged after a short service period; the end-rings start to break away, start to break away. The results of service tests conducted during normal train runs are presented in the paper. The investigation possibilities were limited to recording load currents and vibrations of four motors installed at two bogies of one car. It has been concluded that the reason for rotor winding damage may be traced back to the simultaneous impact of four factors: 1) transmission of load torque by mechanical gearbox; there is a backlash between the pinion mounted at the motor shaft and the toothed gear mounted at the drive bogie axle; 2) rigid assembly of the motor in the bogie frame and vibrations transmitted from the drive wheels to motor; 3) variable components of electromagnetic torque generated by higher harmonics of inverter voltage and current; 4) parallel operation of two unmatched motors supplied from common inverter.

Due to energy saving policy in the European Union and development of power electronics technology, one might expect an increase in the use of solutions, such as inverters in the substations of the 3 kV DC power supply system. The paper includes a study case of the analysis of traffic conditions on the use of inverters in 3 kV DC system traction substations so as to send back trains’ braking energy from a DC traction power supply to an AC power supply network. The authors presented possible estimated energy savings for a selected railway line. Furthermore, the character of a power waveform and energy available for transferring from a DC to an AC power supply network was discussed as well. The effectiveness of this solution largely depends on the nature of train traffic, so prior to applying the inverters, a detailed analysis is required.

The article presents results of iced wire’s temperature approximation during process of heating this wire to melt ice. This approximation was implemented in Matlab using a two-layer feedforward artificial neural network (ANN). The results of the approximation are acceptable, but it is possible to improve them.

In this paper, the requirements of quasi-constant weight code parameters are considered for a certain number of encoded messages and for various requirements of noise immunity. An algorithm is proposed for choosing the optimal parameters of a quasi-constant weight code for a given number of encoded messages and a level of noise immunity that would ensure maximum speed of control command transmission.

This article presents the concept for using an LLC resonant converter equipped with a medium-frequency transformer to upgrade the existing EU 07 locomotive into a dual-system vehicle. The work was created which sets out the specification for such an upgrade, but the design was eventually rejected by the investor and it became the subject of a diploma thesis.

Reduction of the switching losses in three-phase voltage source inverters can be achieved by using of soft switching systems that not only increase the efficiency of the inverters, but they also reduce the size of the semiconductor cooling circuits, that is especially important in traction vehicles. The majority of existing soft switching systems have some drawbacks that could be danger for inverter operation in the case of disturbances in control systems. The paper briefly describes the structure, operation principles and results of laboratory tests of the proposed soft switching system. Particular attention has been paid to the specific features of alternative versions of the proposed soft switching system, that allow to improve operating parameters of the basic system.

The paper presents a method of the simulation of the pipeline potential shift produced by D.C. traction stray currents which are stochastic in character. The calculation model presented is based on the deterministic model used in the earth-return circuit theory combined with the non-deterministic approach based on the Monte Carlo procedure. The model of the equivalent rail with current energization and the concept of superposition allow one to consider more complicated D.C. railway systems using a segmental approximation of the complex railway route and taking into account a number of substations and loads at any location. A locomotive position and a load current are assumed to be independent random variables in the non-deterministic approach. Using simulation program developed random characteristics of a pipeline response e.g. maximum, minimum, median and mean values can be obtained. Hence the pipeline regions more exposed to corrosion risk can be determined.

The drilling of small cylindrical (D < 1 mm) holes with a high ratio of length to diameter (L/D > 10) in difficult-to-cut materials is significantly beyond mechanical drilling capabilities. Electrodischarge machining (EDM) is a good and cost effective alternative in such situations. The machinability of electrodischarge machined material is determined by its thermal and electrical properties; therefore, the high electrical resistivity, the relatively high melting point and low thermal conductivity of Ti-6Al-4V alloy cause problems during the machining of parts made of this material. In this article, the results of experimental research on electrodischarge microdrilling in Grade 5 Ti-6Al-4V alloy are presented. The influence of various machining parameters (pulse time, discharge voltage, current amplitude, dielectric pressure, electrode-tool rotation speed) on key technological factors such as hole depth, side gap, linear tool wear, mean drilling speed and hole taper angle was analysed.

The article summarizes research on a method used to improve tribological properties. The paper presents possibilities of using laser surface modification by means of EDM. The performed research confirmed that the concentrated laser beam stream can effectively modify the state of the ESD coating layer, WC-Cu and improve their usability. The work aims to assess the properties of coatings after laser treatment, based on the observation of the newly created structure of the material, the measurement of adhesion and microhardness measurement.

The paper discusses fire parameters of individual layers of anti-graffiti coating systems proposed for use in rail transport. Modifications and their effect on flammable properties of these coatings have been described. Performed tests included, first of all, parameters such as lateral spread of flame over the surface and heat emission, whose fulfillment proved the most difficult in the previous studies. For this purpose, polyester putties were tested on an epoxy primer. Then, fire parameters for different anti-graffiti systems containing a swelling layer as an additional protective layer were determined.

The paper presents the results of heat treatment tests of HS6-5-2 high speed steel with laser working in continuous mode. The tests used steel in the delivery state as well as steel after fluid treatment aimed at diffusion enrichment of the surface layer with carbon and nitrogen. The aim of the research is to determine changes in the structure of steel enriched with carbon and nitrogen and then subjected to the impact of the laser beam.

Cold spraying is a new technology which can be used in the area of additive manufacturing. This method is suitable for oxygen-sensitive materials, such as titanium. In this paper the microstructure and mechanical properties of cold sprayed titanium deposit were characterized.