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The dynamic response of railway tracks is a key factor influencing the operational safety and reliability of rail transport. Classical analytical methods for modelling track dynamics become insufficient at higher operating speeds, as they typically assume linear behaviour and cannot account for nonlinearities present in the fastening system or in the rail track foundation response. This increases the risk of damage, leading to traffic interruptions, financial losses, and reduced safety. To support predictive maintenance, it is necessary to develop databases based on in-situ measurements, complemented with synthetic data obtained from validated analytical and semi-analytical models. This paper presents such a model, designed to analyse how the parameters of the track foundation – including stiffness and damping – affect the track’s dynamic response to loads generated by a moving railway vehicle. The model incorporates experimentally confirmed nonlinear stiffness of the fastening system, represented by a viscoelastic layer that provides continuous support for the rails.

High-speed rail (HSR) systems provide numerous benefits, including reduced travel time, increased transport capacity, and lower environmental impact compared to conventional rail networks. Recent experience in Poland has confirmed that the design of high-speed rail lines requires the development of new, dedicated structural solutions. One such example is the need to assess the load-bearing capacity of the column-to-foundation connection, which in Poland is designed as a connection with a spacing between the column base plate and the top part of the pile foundation – an uncommon solution in HSR applications. The study included the development of a fatigue damage spectrum in the high-cycle range, taking into account stress variability caused by pressure fluctuations from passing trains. The results establish a relationship between the number of load cycles and pressure values, enabling a simplified estimation of the fatigue strength of the examined connection. Wind effects are influenced by several factors, including train speed, aerodynamic shape, and the angle of load application. The study highlights the sensitivity of the system to boundary conditions and recommends design improvements to enhance fatigue resistance. The novelty of the work lies in identifying critical failure modes specific to distance-type connections and emphasizing the need for full-scale experimental validation in the context of HSR development in Poland.

The study aimed to compare the quasi-static moduli determined from the empirical Barton relationship with the dynamic modulus of elasticity for various types of rock strata. Both moduli were determined from measured P- and S-wave velocities obtained by seismic refraction profiling or seismic tomography. The moduli were calculated using the Barton relationship, which requires only the P-wave velocity, while the dynamic modulus of elasticity was calculated from the P- and S-wave velocities and the bulk density of rock material. The study was conducted on various rock masses, ranging from weak, highly fractured, weathered rock to very strong rock, at different depths in Poland. The study revealed that the dynamic modulus of elasticity is significantly higher than the quasi-static deformation moduli. The relative difference between the moduli ranges from 13 to 54%. In rocks more heavily fractured by weathering and anthropogenic activity, the difference in moduli was greatest, ranging from 44 to 54%. For other rocks with less weathering and not disturbed, the relative difference ranged from 13 to 20%. More severe fractures, resulting from both weathering and anthropogenic activity, result in greater discrepancies in modulus calculations. These findings provide more effective insights into the applications of seismic-determined moduli in geotechnical problems.

Problems concerning structures dynamics are being one of most important subjects in recent investigations associated with railways constructions. The need of modelling of such structures and their behaviour prediction leads to necessity of seeking new approaches, mainly due to highly increasing speeds of vehicles and traffic intensity. Comparative studies carried out on experimental data, measurements and theoretical research show that models based on multi-layered approach supported by semi-analytical approximations of solutions can give new insight into undertaken analyses. More detailed consideration of roads components and their physical properties, along with application of effective estimations allowing to avoid numerical instabilities linked with extremal dynamic variations, can be important tools in obtaining new solutions both, theoretical and engineering. This paper briefly presents a number of multilayer railway track models, with special emphasis on nonlinear track properties. Existing analytical and semi-analytical solution methods are presented with main advantages of new approaches. The theoretical double-beam system with two nonlinear layers is solved and computational examples are presented along with possibility of their transition to other multilayer structures analysis.

It is assumed in the paper that the signals in the enclosure in a transient period are similar to a noise induced by vehicles, tracks, cars, etc. passing by. The components of such signals usually points out specific dynamic processes running during the observation or measurements. In order to choose the best method of analysis of these phenomena, an acoustic field in a closed space with a sound source inside is created. Acoustic modes of this space influence the sound field. Analytically, the modal analyses describe the above mentioned phenomena. The experimental measurements were conducted in the room that might comprise the closed space with known boundary conditions and the sound source Brüel & Kjær Omni-directional type 4292 inside. To record sound signals before the field's steady state was reached, the microphone type 4349 and the 4-channel frontend 3590 had been used. The obtained signals have been analysed by using two approaches, i.e. Fourier and the wavelet analysis, with the emphasis on their efficiency and the capability to recognise important details of the signal. The results obtained for the enclosure might lead to the formulation of a methodology for an extended investigation of a rail track or vehicles dynamics.

P-wave velocity in coal seams increases with depth and reflects the in situ stress state in the rock mass. Anomalous velocity can indicate changes in the stress state resulting from various mining and geological disturbances. This information could contribute to the more efficient mining of coal at greater depths, particularly in seismically prone areas. The empirical relationship between P-wave velocity in coal seams and depth, developed by Dubiński in 1989, enables the determination of the magnitude of the velocity anomaly. However, this relationship was determined based on measurements taken to a depth of approximately 900 m. Currently, mining in the south-western Upper Silesian Coal Basin extends to greater depths, reaching around 1300 m. This study aims to update the empirical relationship for calculating reference P-wave velocities in coal seams by including new data. The archival 252 measurements were combined with 74 new velocity data from greater depths up to 1281 m. Regression analysis revealed that the updated power model offers a more reliable description of velocity changes in coal seams with increasing depth. This updated model can be used to identify anomalous stress zones and implement special protective measures in endangered mine workings. Our findings may contribute to reducing the risk of dynamic phenomena and enable more efficient exploitation of deep-seated coal seams.

Platinum-based chemotherapy with third generation drugs (such as gemcitabine) is an efficacious regimen of first-line treatment of patients with advanced, unresectable non-small cell lung cancer (NSCLC), without activating EGFR mutations. Mechanism of action of cytostatics are distortions in the DNA. ERCC1 and RRM1 are key proteins involved in the repair of DNA, thus, they may be responsible for the ineffectiveness of therapy. We investigated whether ERCC1 (19007C>T) and RRM1 (−37C>A) polymorphisms impact response to chemotherapy and survival in 62 patients with NSCLC treated with platinum and gemcitabine. Single nucleotide polymorphisms (SNPs) were assessed using a PCR-RFLP method in DNA isolated from PBLs. There were no statistically significant relationships between ERCC1 genotypes and response to therapy (P=0.581, χ2=1.09) as well as patient overall survival (OS). Carriers of the RRM1 AC genotype showed disease progression significantly more frequently (P=0.019, χ2=5.473) compared to carriers of the AA or CC genotypes. Carriers of the ERCC1/RRM1TT/CC genotype combination showed disease control significantly more frequently (P=0.047, χ2=3.95) compared to carriers of other genotype combinations. Patients with AA or CC genotypes of RRM1 showed significantly higher progression-free survival probability (P=0.0001, HR=0.39, 95% CI, 0.22-0.70) and OS probability (P=0.0104, HR=0.39, 95% CI, 0.18-0.82) compared to those with the AC genotype. In Cox regression model, poor performance status (P=0.0016, HR=4.78, 95% CI, 1.82-12.56), AC genotype of RRM1 gene (P=0.0414, HR=2.47, 95% CI, 1.04-5.87), lack of prior surgical treatment (P=0.0425, HR=4.71, 95% CI, 1.06-20.92) and lack of subsequent lines of treatment (P=0.0127, HR=3.23, 95% CI, 1.29-8.11) were significantly associated with shortening of patient survival. The analysis of RRM1 (−37C>A) more than ERCC1 (19007C>T) polymorphism may be a promising tool in the qualification of NSCLC patients for chemotherapy containing platinum compounds and gemcitabine.

It is known that nonlinear and stochastic properties of structures should be taken into account in the analysis of their dynamic behaviour. This statement remains valid for railway infrastructure, where trains acting on rail track cause their strong dynamic variations. It becomes even more important when one deals with high frequencies and speeds of trains. The recent HSR networks need new technologies and materials in order to increase train speeds and, in the same time, to protect the environment against negative factors produced by operational lines. Therefore all important aspects of new railway constructions should be analysed, especially in terms of mechanical vibrations and noise attenuation. The elements of rail tracks, such as sleepers, under sleeper pads, rail dampers, fastening systems and others, have nonlinear properties. Their influence on dynamic behaviour of railway tracks is still insufficiently researched. For this purpose, various analytical models are proposed which can give a new insight into detailed dynamic characteristics of such structures.

Damage to large reinforced concrete structures is rarely due to design errors. Sometimes, however, a small error can lead to major damage and costly repairs. The article describes the damage, the results of non-destructive and destructive tests, the results of numerical calculations, and the method of repairing a reinforced concrete tank in a sewage treatment plant. The failure was caused by applying the wrong boundary conditions to the reinforced concrete wall support inside an existing biological reactor. During leak testing, one of the new walls cracked and was displaced, which resulted in the tank leaking. An inspection of wall damage and displacement was carried out on termination of the leak testing and while the tank was draining. The causes of the failure were determined based on the inventory information and numerical simulations. Both non-destructive tests of reinforcement and concrete and destructive tests of concrete were carried out. The concrete class of the foundation slab was determined based on a compression test of sample cores obtained from drilling. The aim of the non-destructive tests was to indicate the location and diameter of reinforcement in the damaged wall using electromagnetic and radar methods, as well as the location of internal defects using ultrasonic and radar methods. It was found out that the failure was a result of an incorrect determination of the anchoring length of the reinforcement. Based on the analysis, a plan to repair the damaged wall was formulated and then successfully implemented. In the article the authors proposed the IVD (identification-verification-design) scheme to make the design easier in similar cases.

Phenomena associated with railway dynamics are usually analysed by using numerical approaches due to high computational complexity of such systems. However, classical methods based on analytical modelling are still highly valued and desirable by researchers and railway industry. This paper presents analytical solution representing dynamic response of railway track due to moving train in the case of nonlinear foundation. In published papers, one can find analyses of various characteristics such as velocity and acceleration of vibrations of track layers or bending moments of rails. The approach applied in this paper uses the Fourier transform combined with wavelet based approximation applied to the systems of infinitely long beams. The system of Euler-Bernoulli beams resting on viscoelastic foundation represents two-layer model (or one-layer model) of railway track, commonly used in engineering studies. It is shown that although both methods give good results for displacements, analysis of other characteristics, involving derivatives of higher orders, might lead to wrong results, even in the linear case. Possible reasons of this problem are pointed out. Some modifications of the known dynamic railway track models are proposed for further work.