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Simulation assessment of the headway under the ETCS L3
Get PDFThis paper deals with a simulation assessment of the impact of the introduction of ETCS L2 and L3 on the capacity of railway lines. The simulation itself is carried out in the OpenTrack simulation software, especially in the tool headway calculator. For this research, an infrastructure model has been built, which represents a typical layout of lines and stations in the Czech Republic. By successive modifications of the model, the significance of the impact of the implementation of ATP systems on the capacity of lines can be simulated. In the paper, the influence of the implementation of different application levels of ATP systems on the capacity of railway lines is evaluated
Evaluation of deformation and strength parameters of organic soils for the design of geotechnical structures
Get PDFThe evaluation of deformation and strength parameters of Holocene organic soils obtained from DMT dilatometer tests based on empirical relationships and ANN Artificial Neural Networks is presented. The evaluation of undrained shear strength τfu, deformation modulus E0.1% and initial shear modulus G0 of Eemian organic soils obtained from DMT dilatometer tests and SDMT seismic dilatometer tests is given, and then its comparison with the values obtained from triaxial tests for the design of underground structures supported by diaphragm walls of the stations of the underground line II in Warsaw, is shown
Analysis of the influence of side wall opening on the arch structure of metro station using the PBA method
Get PDFIn order to meet the traffic and commercial needs, it is sometimes necessary to open the side wall of the metro station, while the current research on the mechanical properties and safety of the arch caused by the opening of the side wall of the station by pile-beam-arch (PBA) method is rarely involved. In this paper, based on the Tianhe East Station project of Guangzhou Metro Line 11 located in soft-hard uneven stratum using PBA method, the settlement law and mechanical characteristics of the arch under different side wall opening conditions is analyzed, and the influence of opening construction and opening span on the safety of arch is also further studied. The results show that the settlement caused by the opening of the side wall is mainly concentrated in the upper part of the opening area, and gradually expands around the opening area with the increase of opening span, and the maximum settlement occurs in the middle part of the arch. Opening leads to the differential settlement at both ends of the arch. With the increase in opening span, the settlement growth trend of the right side of the arch is greater than that of the left side. The opening of the side wall leads to the increase of the safety factor of the arch body and the decrease of the safety factor of the right arch foot, while the change of the safety factor of the left arch foot is not obvious, and the safety factor meets the specification requirements
Application of cold atmospheric plasma for mold inactivation
Get PDFMold growth in indoor interiors is an increasing problem that has adverse effects on both occupants and building materials. The aim of this study was to present the new environmentally friendly method (cold atmospheric plasma treatment) for decontamination of indoor environments contaminated by mold spores, with the potential to become an effective replacement for conventional methods, such as ultraviolet-C (UV-C) germicidal irradiation. The spores of Aspergillus species on malt extract agar plates were exposed to plasma produced by diffuse coplanar surface barrier discharge. The surface coverage of mold was evaluated using image analysis. Cold plasma treatment inactivated spores on the surface of the culture medium in 0.5 min, whereas a weak growth delay was observed after 30 minute exposure to UV-C irradiation. This study demonstrated that cold atmospheric plasma is a more effective method for reducing mold spores on agar compared with germicidal UV-C irradiation
Effect of electric current on porosity of concrete
Get PDFThe paper describes the influence of electric current on the porosity of concrete samples after electrically accelerated tests and other electrokinetic treatments. Three different concrete mixtures consisting of CEM I 42.5R, CEM II / A-M(S-LL) 42.5R, and CEM I 42.5R with 10 % replacement of cement by microsilica were examined. Direct current (DC) test was performed on fully saturated samples. The samples were loaded with a constant voltage of 20 V for 24 hours in chambers filled with NaOH solution. The changes in porosity were examined using mercury intrusion porosimetry (MIP), scanning electron microscopy (SEM), and open porosity (OP). The results of open porosity indicate an increase in porosity for all mixtures measurements of ∼0.6 %–2 % for treated samples. The MIP showed increase of volume of pores with radius smaller than 0.01 μm after DC test. According to X-ray diffraction (XRD) and Thermogravimetric analysis (TGA) there was ∼2 % less calcite after DC test
THE EFFECT OF RECYCLED RUBBER AGGREGATES AND DUNE SAND OF EL-OUED REGION ON THE COMPRESSIVE STRENGTH OF CEMENTITIOUS MORTAR: OPTIMIZATION USING TAGUCHI METHOD
Get PDFThis study optimizes the effect of recycled rubber aggregates and dune sand of El-Oued\u27s region by maximizing the compressive strength of cementitious mortar using Taguchi\u27s design experiments. The experiments were designed using an L9 orthogonal array to see the different relationships between the factors targeted in our research, namely: water/cement (W/C) ratio, rubber aggregates (RA) content, and dune sand (SD) content, with the levels of each factor in the mortar mixture. The samples were tested at 28 days in each of the nine trial conditions for two responses: compressive strength and ultrasonic pulse velocity. The results of the analysis of variation (ANOVA) show that RA content is the factor that has the largest effect on the two tests, and the second factor affecting the two tests is the W/C ratio. Then, the analysis shows that the SD content has no significant effect on the mechanical resistance of the mortar for the two tests. And from the mathematical models investigated in this study, we conclude that the factors RA content and W/C ratio have a negative influence on the responses of the compression test and the ultrasonic test togethe
FUNCTIONAL USE OF THE AREA OF PRAGUE CASTLE WITH EMPHASIS ON THE NORMALIZATION PERIOD
Get PDFThis paper deals with individual typological types and units in the Prague Castle area. It also focuses on the urban and historical development, as it is significantly influenced by the situation in the period under study. It focuses more closely on the period of the second half of the 20th century, and especially the period of normalization - the 1970s and 1980s.
Prague Castle was and still is the seat of the monarch, or today the President of the Czech Republic. The historical context has had a considerable influence on the shape of the Castle (the succession of ruling personalities from different dynasties, the transformation from the position of the seat of the Habsburg monarchy and therefore the most important center in Central Europe to the position of the summer residence of the ruling family, etc.). Also unprecedented is the concentration of the main buildings of secular and ecclesiastical power in one area. The castle is a huge complex, combining morphological assumptions with the result of the work of a huge number of people. A number of foreign artists worked here, reaching world-class standards and both understanding and supporting the local genius loci. There are also many contrasts - political and constructional. For example, the imprints of monarchy and republic, church and secular power, ancient and modernist architecture, contrasts between the smallest buildings of houses and the largest palaces.
On the basis of archival research and the study of expert literature, the reader is introduced to the progressive changes in the layout of the Castle complex and the associated changes in the functional use of the buildings and spaces in the aforementioned complex
Use of lightweight FFT-based algorithms for remote measurements using DIC
Get PDFAbrupt collapse events that result in casualties due to failure of load-bearing structures have been reported in recent years. Continuous remote monitoring of these structures, assessing the behavior under operational load, could provide a reliable prevention, as the developing damage manifests itself through a loss of stiffness, and therefore excessive deflections. Digital image correlation (DIC) algorithms based on fast Fourier transform (FFT) were implemented in a small computer unit Raspberry Pi, capable of remote operation in a low-energy demand mode. The unit is fully autonomous, capable of localizing QR code targets and extracting encoded information. This strategy allows us to instantly evaluate displacements of QR codes attached to any surface and send the data to a server. The software was developed in Python, allowing for two modes: the online mode for current data evaluation with information transfer via the MQTT protocol and the offline mode used for retrospective evaluation
Model-based Optimization of the Switching Performance of a Switch Disconnector
Get PDFLow voltage switch disconnectors (SD) combine rated load switching with disconnector functionality, providing safe electrical isolation. Electrical contacts are separated forming an arc discharge that needs to be quenched at first current zero (CZ) to protect the load and the SD itself. With increased line voltage, interruption at first CZ crossing is getting more difficult due to increased transient recovery voltage (TRV) and larger post arc current, leading to excessive contact erosion with longer arcing time. Arc simulation methodology was utilized to improve the design for better arc cooling close to CZ. Therefore, benchmark values of arc resistance and thermal time constant were evaluated close to CZ for a successful test at lower line voltage. The cooling efficiency of different designs at higher line voltage was analyzed by 3D arc simulation. A revised design was able to clear overload currents at lower and higher line voltages at first CZ, preventing excessive contact damage
Optical Diagnostics of Anode Surface Temperature in Vacuum Interrupters with Different CuCr Compositions
Get PDFThe requirements for contact material in vacuum interrupters are demanding because the arc medium is formed by electrode evaporation during the operation. Copper chromium alloy (CuCr) is widely used as contact material. Different compositions could result in a different rate of successful interruption. This work compares vacuum arc properties for two CuCr compositions - 75/25 and 50/50 weight percent. The contact surface temperature is measured during and after the vacuum arc with an AC current flow at 2kA magnitude. Quantitative characterization of the contact surface temperature was obtained with near-infrared spectroscopy using Planck curve fitting and spectrally filtered high-speed photography. Evaluation of the anode surface temperature has shown a slower surface cooling for CuCr 50/50 compared to 75/25. Despite this, CuCr 75/25 has experienced higher temperature with dispersion in a larger area during the arcing time, in a successful current interruption