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This article presents an efficient methodology for the calibration of a numerical model of a Sgnss freight railway wagon based on experimental modal parameters, namely natural frequencies and mode shapes. Dynamic tests were performed for two distinct static loading configurations, tare weight and current operational overload, under demanding test conditions, particularly during an unloading operation of the train and without disturbing its tight operational schedule. These conditions impose restrictions to the tests, especially regarding the test duration, sensor positioning and system excitation. The experimental setups involve the use of several high-sensitivity accelerometers strategically distributed along with the vehicle platform and bogies in the vertical direction. The modal identification was performed with the application of the enhanced frequency-domain decomposition (EFDD) method, allowing the estimation of 10 natural frequencies and mode shapes associated with structural movements of the wagon platform, which in some cases are coupled with rigid body movements. A detailed 3D FE model of the freight wagon was developed including the platform, bogies, wheelsets, primary suspensions and wheel–rail interface. The model calibration was performed sequentially, first with the unloaded wagon model and then with the loaded wagon model, resorting to an iterative method based on a genetic algorithm. The calibration process allowed the obtainment of the optimal values of eight numerical parameters, including a double estimation of the vertical stiffness of the primary suspensions under the unloaded and loaded static configurations. The results demonstrate that the primary suspensions present an elastic/almost elastic behaviour. The comparison of experimental and numerical responses before and after calibration revealed significant improvements in the numerical models and a very good correlation between the experimental and numerical responses after calibration. [ABSTRACT FROM AUTHOR]

Jarnicki, Myrvold, Saltzman, and Wagon conjectured that if G is Hamilton-connected and not K 2 , then its Mycielski graph μ G is Hamilton-connected. In this paper, we confirm that the conjecture is true for three families of graphs: the graphs G with δ G > V G / 2 , generalized Petersen graphs G P n , 2 and G P n , 3 , and the cubes G 3 . In addition, if G is pancyclic, then μ G is pancyclic. [ABSTRACT FROM AUTHOR]

Jarnicki, Myrvold, Saltzman, and Wagon conjectured that if G is Hamilton-connected and not K 2 , then its Mycielski graph μ G is Hamilton-connected. In this paper, we confirm that the conjecture is true for three families of graphs: the graphs G with δ G > V G / 2 , generalized Petersen graphs G P n , 2 and G P n , 3 , and the cubes G 3 . In addition, if G is pancyclic, then μ G is pancyclic. [ABSTRACT FROM AUTHOR]

The dynamic loading and strength of the frame of the “East-West” type covered wagon were determined. To increase the efficiency of operation of covered wagons in international traffic, it is proposed to improve their frames. This improvement consists in using a sectional partition in the body in order to divide it into two separate sections. This allows the transportation of different goods in one wagon, and therefore decreasing empty mileage. The longitudinal loading of the covered wagon frame was determined. The case of shunting impact was considered. The studies were carried out in a flat coordinate system. The loading mode of the frame of the covered wagon in the empty and loaded states was considered. The acceleration acting on the covered wagon frame in the loaded state was 0.37g, empty – 0.42g, which does not exceed the standard values. The wagon motion is rated “excellent”. The main strength indicators of the covered wagon frame were determined. The calculation was made by the finite element method. It was found that the maximum equivalent stresses are concentrated in the area of interaction of the center sill with the bolster beam and amounted to 340 MPa, which is lower than the yield stress of the material. Maximum displacements occur in the middle of the frame beams and are about 12 mm. The natural vibration frequencies of the covered wagon frame were calculated. The research will help to increase the efficiency of using covered wagons in international traffic. Also, the research results can be useful developments in the creation of innovative rolling stock structures. [ABSTRACT FROM AUTHOR]

The polygonal wear around the wheel circumference could pose highly adverse influences on the wheel/rail interactions and thereby the performance of the vehicle system. In this study, the effects of wheel polygonalisation on the dynamic responses of a freight wagon are investigated through development and simulations of a comprehensive coupled vehicle-track dynamic model. The model integrates flexible ballasted track and wheelsets subsystem models so as to account for elastic deformations caused by impact loads induced by the wheel polygonalisation. Subsequently, the vehicles with low-order polygonal wear, whether in empty or loaded conditions, are simulated at different speeds considering different amplitudes and harmonic orders of the wheel polygonalisation and thus the mapping relation between wheel/rail impact force and wheel polygonalisation is obtained. The results reveal that the low-order wheel polygonalisation except 1st order and 3rd order can give rise to high-frequency impact loads at the wheel/rail interface and excite 1st-bend modes of the wheelset and "P2 resonance" leading to high-magnitude wheel/rail contact force at the corresponding speed. [ABSTRACT FROM AUTHOR]

The high safety factor expected from transport vehicles results in high costs. Moreover, the environmental and financial concerns in transport vehicle technology make the minimization of production factors obligatory. This causes a decision problem between high safety and production at low cost. In this study, modeling and analysis with multi-criteria decision-making methods for freight wagon bogie operating with high safety and minimum cost were aimed. The decision problem was created considering the factors of safety, manufacturability and cost for three different materials, and the most appropriate material combination was determined for the bogie construction. In data production for the decision factors, the application of computer-aided engineering and chemical content of the materials were taken into consideration. The real tonnage prices of the related material were used for the cost criterion. TOPSIS, VIKOR and SAW, which are among the multi-criteria decision-making methods, were used for the solution of the decision problem. Fishbone, Cronbach's alpha and regression methods were used for quality and reliability analysis. It was found that the solutions obtained from the chosen models validate each other. Together with the concept of economy and computer-aided engineering applications, its successful applicability to decision problems developed for freight wagons and providing a solution to them is the originality of this paper. According to the methods, the ideal solution was found as the material S355 for the pivot, S235 for the carrier and the bolster. According to reliability analysis, the data produced were found statistically sufficient and significant (Adj. R-Sq's obtained above 95%). [ABSTRACT FROM AUTHOR]

Today, in modern Russia, the decrease in wear resistance and contact fatigue endurance of locomotive and waggon wheels is the main and most expensive problem in the railway industry. In this scientific work, we studied the application of the magnetic structural method of measuring coercive force (coercimetry) to analyse and evaluate the condition of wheeled steel of grade 2 after heat treatment. [ABSTRACT FROM AUTHOR]

Jarnicki, Myrvold, Saltzman, and Wagon conjectured that if G is Hamilton-connected and not K 2 , then its Mycielski graph μ G is Hamilton-connected. In this paper, we confirm that the conjecture is true for three families of graphs: the graphs G with δ G > V G / 2 , generalized Petersen graphs G P n , 2 and G P n , 3 , and the cubes G 3 . In addition, if G is pancyclic, then μ G is pancyclic. [ABSTRACT FROM AUTHOR]

Jarnicki, Myrvold, Saltzman, and Wagon conjectured that if G is Hamilton-connected and not K 2 , then its Mycielski graph μ G is Hamilton-connected. In this paper, we confirm that the conjecture is true for three families of graphs: the graphs G with δ G > V G / 2 , generalized Petersen graphs G P n , 2 and G P n , 3 , and the cubes G 3 . In addition, if G is pancyclic, then μ G is pancyclic. [ABSTRACT FROM AUTHOR]

This paper reports determining the basic strength indicators for the removable roof of a railroad gondola. It has been established that the typical roof design has a significant margin of safety in the components of the supporting structure. In order to reduce the roof material intensity, the reserves of its strength have been determined and optimized based on the criterion for minimal material intensity. Pipes of square cross-section have been proposed for using as the components of the roof frame. When taking into consideration the proposed measures, it becomes possible to reduce the mass of the frame of the removable roof for a railroad gondola by almost 15 % compared to the typical design. At the same time, to apply the roof on different types of gondolas, its cantilevered parts can move in a longitudinal plane. It is possible to use deflectors on the removable roof. The roof can be attached to the body in a regular way. It is also possible to fix it using shog-connections. To substantiate the proposed solution, the strength of the improved structure of the removable roof was determined. It was established that the maximum equivalent stresses in the load-bearing structure of the removable roof did not exceed permissible ones. To define the indicators of removable roof dynamics, its dynamic loading was investigated. The calculation was performed in a flat coordinate system. The oscillations in bouncing and galloping were taken into consideration as the most common types of a railroad car oscillations when running on a rail track. The mathematical model of dynamic loading was solved in the Mathcad software package (Boston, USA). The study has shown that the acceleration of the body in the center of masses is 0.4 g and is within the permissible limits. At the same time, the ride of a railroad car is excellent. The study reported here would contribute to the improvement of the efficiency of railroad transportation. [ABSTRACT FROM AUTHOR]

The use of vehicle communication can improve the safety, efficiency and productivity of a wide range of commercial vehicles. The use of wireless networks for vehicle communications and communications for other types of vehicles (freight wagons, buses, agricultural vehicles, construction vehicles and mining vehicles) can be achieved through the use of special devices implemented in these vehicles. These devices change information on road safety, mobility and the environment by informing the driver. Most of this information comes from sensors located on / in the vehicle. New technologies launched on the automotive market provide higher data read speeds and a much higher transfer rate. They can also quickly process new types of sensory data. An example is commercial vehicle sensors that process and interpret data from different types of sensors. [ABSTRACT FROM AUTHOR]

An editorial is presented on current experiences and perspectives of the era for posterity in the field of art education. Topics include burgeoning movement calling out systemic racism and inequality, art education theorists, and practitioners; and older books from the libraries and personal collections jumping on new bandwagons before exhausting the possibilities of the preceding wagons.

We describe the Bayesian analysis of nuclear dynamics (BAND) framework, a cyberinfrastructure that we are developing which will unify the treatment of nuclear models, experimental data, and associated uncertainties. We overview the statistical principles and nuclear-physics contexts underlying the BAND toolset, with an emphasis on Bayesian methodology's ability to leverage insights from multiple models. In order to facilitate understanding of these tools, we provide a simple and accessible example of the BAND framework's application. Four case studies are presented to highlight how elements of the framework will enable progress in complex, far-ranging problems in nuclear physics (NP). By collecting notation and terminology, providing illustrative examples, and giving an overview of the associated techniques, this paper aims to open paths through which the NP and statistics communities can contribute to and build upon the BAND framework. [ABSTRACT FROM AUTHOR]

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The interactions of microbes with plant cells can radically change plant-cell form and function. A new study shows how a specialised formin protein paves the way for nitrogen-fixing bacteria to make homes in legumes. [ABSTRACT FROM AUTHOR]

The effect of the rate of change of fresh air inside passengers' wagons for Underground Metro on the spreading of airborne diseases like COVID-19 is investigated numerically. The study investigates two extreme scenarios for the location of the source of infection within the wagon with four different air change rates for each. The first scenario considers the source of infection at the closest point to the ventilation system while the other places the infection source at the farthest point from the wagon ventilation system. The effect of the wagon windows' status (i.e. closed or open) is also studied. It is found that under all conditions, open windows are always favored to decrease the infection spreading potential. A higher air change rate also decreases the infection spreading up to a certain value, beyond which the effect is not noticeable. The location of the infection source was found to greatly affect the infection spreading as well. The paper gives recommendations on the minimum air change rate to keep the infection spreading potentials to a minimum considering different times the passengers stay in the wagon. [ABSTRACT FROM AUTHOR]

This research is concerned with the use of double walls filled with foam aluminum for an open wagon to decrease loading during operational modes. The research presents the strength calculation for the frame of a wagon with a consideration of the engineering solutions proposed. It was found that the maximum equivalent stresses appeared in the bottom section of the center sill behind the back support; they amounted to about 290 MPa and did not exceed the allowable values. The maximum displacements were in the middle parts of the main longitudinal beams of a section, and they amounted to 8.8 mm. The research also presents the strength calculation for a weld joint in the maximum loaded zones of the frame of a wagon and reports the results of the modal analysis of the frame of the improved wagon. It was found that the oscillation frequencies did not exceed the allowable values. The results of the research may be useful for those who are concerned about designing innovative rolling stock units and improving the operational efficiency of railway transport. [ABSTRACT FROM AUTHOR]

The observation that cities are growing rapidly especially in the African continent is well acknowledged around the world. Indeed, 'an urban-centric discourse' has emerged to assert that the future is 'urban' as more people are moving to live in cities (UN, 2018). While the issue of growth cannot be challenged, one needs to look at the dangers of this discourse in African cities. The dynamics of urban growth in African cities are more complex and different from industrialised Europe from which this discourse is modelled. Hence, the patterns of contemporary urban growth and economic transformation in Africa might well undermine assumed urban-centric theoretical associations. [ABSTRACT FROM AUTHOR]

A study of the dynamic loading of the carrying structure of a tank wagon during transportation on a railway ferry was carried out. The studies were carried out with the angular displacements of the railway ferry around the longitudinal axis (lurch), as the case of the highest load on the carrying structure of the tank wagon. It was found that the acceleration total value that acts on the outermost tank wagon from the bulwark is 0.31g. The resulting value of acceleration, as a component of the dynamic load, was taken into account when calculating the strength of the carrying structure of the tank wagon, taking into account the typical scheme of interaction with chain ties. The research carried out will contribute to the creation of recommendations for the safe operation of tank wagons in international rail and water traffic and increasing the efficiency of rail transport functioning. [ABSTRACT FROM AUTHOR]