Improvement in Performance of the Sulphuric Acid Transport Installation through Modification of Flow Characteristics Using Electric Actuators

The paper presents a flow model of the installation for tank car filling with sulphuric acid (VI). For the mathematical modelling of the flow process in the industrial installation, a model diagram of the object and experiments carried out during the installation work were applied. The analysis of specific experimental series showed unusual shapes of mass flow characteristics vs. the valve opening level (too wide hysteresis), which markedly deviated from typical flow characteristics that are found in standards and literature. As a result of flow modelling in the sulphuric acid installation, a better-shaped characteristic was presented that should be obtained based on the measuring system values in the absence of the inertia-related error. In the experiments carried out according to the selected procedures, effects of the actuator speed on the characteristics of interest were determined. It was observed that the use of a “slower” actuator (i.e., longer transition time) narrows the characteristics in terms of a reduced difference in flow readings between the valve opening and closing courses. In the specified research procedure for the real flow characteristics, effects of the measurement transducer dynamics in the flow meter on the characteristic course were assessed. It was demonstrated that a faster transducer enabled closer flow recordings to the valve nominal characteristics. The variable speed can improve the positioning precision, with the use of the lowest possible speed rule directly before the positioning point.

CALCULATION OF CAR TRAFFIC CAPACITY AT THE CROSSROAD

The capacity of a road section depends on many factors, such as the width of the carriageway, the permissible visibility, the slopes, the turning radii, the composition of the cars, the maneuverability and the design of the cars. The development of the automotive industry leads to improved performance of cars and improved throughput. Changing all of these components changes the bandwidth. When the capacity is calculating the composition of the traffic flow became one of the key factors. Mobile traffic is characterized by the composition of different (by age and purpose) vehicles. The composition of the traffic flow is displayed as a percentage. Obtaining and analyzing the algorithm for determining the capacity of traffic flow on a particular section of road (interchange). The analyze of the current state of car use in Ukraine and select the optimal algorithm for obtaining real flow data on the road section was made. The main task of the engineer during the design of a certain section of the road is to ensure the maximum capacity of the road section. Maximum throughput is achieved by improving the road surface, widening the roadway (increasing the number of lanes and installing appropriate signs), allocating reversing lanes and installing reversing traffic lights. When calculating the capacity, it is necessary to take into account when characterizing the relationship between cars in the flow in different road conditions. Intervals between cars in a stream can change even at high intensity of movement that in turn quit

Discharge Coefficients of a Heavy Suspension Nozzle

The suspensions used in heavy vehicles often consist of several oil and two gas chambers. In order to perform an analytical study of the mass flow transferred between two gas chambers separated by a nozzle, and when considering the gas as compressible and real, it is usually needed to determine the discharge coefficient of the nozzle. The nozzle configuration analyzed in the present study consists of a T shape, and it is used to separate two nitrogen chambers employed in heavy vehicle suspensions. In the present study, under compressible dynamic real flow conditions and at operating pressures, discharge coefficients were determined based on experimental data. A test rig was constructed for this purpose, and air was used as working fluid. The study clarifies that discharge coefficients for the T shape nozzle studied not only depend on the pressure gradient between chambers but also on the flow direction. Computational Fluid Dynamic (CFD) simulations, using air as working fluid and when flowing in both nozzle directions, were undertaken, as well, and the fluid was considered as compressible and ideal. The CFD results deeply helped in understanding why the dynamic discharge coefficients were dependent on both the pressure ratio and flow direction, clarifying at which nozzle location, and for how long, chocked flow was to be expected. Experimentally-based results were compared with the CFD ones, validating both the experimental procedure and numerical methodologies presented. The information gathered in the present study is aimed to be used to mathematically characterize the dynamic performance of a real suspension.

Stretching and shearing contamination analysis for Liutex and other vortex identification methods

The newly developed vortex-identification method, Liutex, has provided a new systematic description of the local fluid rotation, which includes scalar, vector, and tensor forms. However, the advantages of Liutex over the other widely used vortex-identification methods such as Q, ∆, λ2, and λci have not been realized. These traditional methods count on shearing and stretching as a part of vortex strength. But, in the real flow, shearing and stretching do not contribute to fluid rotation. In this paper, the decomposition of the velocity gradient tensor is conducted in the Principal Coordinate for uniqueness. Then the contamination effects of stretching and shearing of the traditional methods are investigated and compared with the Liutex method in terms of mathematical analysis and numerical calculations. The results show that the Liutex method is the only method that is not affected by either stretching or shear, as it represents only the local fluid rigid rotation. These results provide supporting evidence that Liutex is the superior method over others.

Dynamics of Fourier Modes in Torus Generative Adversarial Networks

Generative Adversarial Networks (GANs) are powerful machine learning models capable of generating fully synthetic samples of a desired phenomenon with a high resolution. Despite their success, the training process of a GAN is highly unstable, and typically, it is necessary to implement several accessory heuristics to the networks to reach acceptable convergence of the model. In this paper, we introduce a novel method to analyze the convergence and stability in the training of generative adversarial networks. For this purpose, we propose to decompose the objective function of the adversary min–max game defining a periodic GAN into its Fourier series. By studying the dynamics of the truncated Fourier series for the continuous alternating gradient descend algorithm, we are able to approximate the real flow and to identify the main features of the convergence of GAN. This approach is confirmed empirically by studying the training flow in a 2-parametric GAN, aiming to generate an unknown exponential distribution. As a by-product, we show that convergent orbits in GANs are small perturbations of periodic orbits so the Nash equillibria are spiral attractors. This theoretically justifies the slow and unstable training observed in GANs.

Analysis of Methods for Determining the Characteristics of a Single Spatial Electromagnetic Field

This paper analyzes the methods for determining the characteristics of a single spatial electromagnetic field; considerations combine all–electric, magnetic, and electromagnetic fields into a single electromagnetic theory of a spatial field. On the basis of the concept of a single field of force spatial interaction of material bodies, it is analytically established that in a physical vacuum only waves of its polarization actually exist, transporting in the space of a vacuum sphere its excitation energy, which when force interacting with a certain physical characteristic (electrical, magnetic or gravitational) material body, creates a dynamic response of the parameters of this body, which is recorded in the experiment as a real flow of energy with responsible of the physical nature.

Fidelity Enhancement of a Multirotor Dynamic Inflow Model via System Identification

Multirotor analytical dynamic inflow models in the literature, such as pressure potential superposition inflow model or velocity potential superposition inflow model (VPSIM), have been shown to capture the fundamental inflow interference effects between the rotors. Some of the differences in inflow predictions seen between these analytic models and high-fidelity wake models are attributed to missing real flow effects such as wake distortion, contraction, decay, swirl, etc. As such, correction terms are needed in the analytically derived multirotor finite-state inflow models, because of the potential flow and rigid wake assumptions they are based on, in order to capture some of the missing real flow effects in them. This paper develops a systematic methodology for arriving at the needed correction terms in the VPSIM through comparisons of its inflow predictions with those of a viscous vortex particle model (VVPM). Also, a procedure is developed to assess the relative importance of individual real flow effects and the associated corrections needed for improving the overall fidelity of the VPSIM. The developed methodology is applied to the Harrington coaxial rotor using its geometric and aerodynamic data from the literature. It is shown that the addition of swirl coupling correction terms to the VPSIM significantly improves its correlations with the VVPM. Further, it is shown that the required corrections are reasonably insensitive to thrust sharing ratio conditions between the rotors.

Assessment of water quality status in the impact area of the “Piškornica” landfill

Disposal of household and industrial waste at the Piškornica site began in 1982 on what was then an unmanaged landfill cell, which allowed contamination to pass into underground layers. Landfill rehabilitation was conducted between 2005 and 2013 and conformed to the environmental protection conditions and measures that were prescribed by an EIA procedure, but rehabilitation still has not been fully completed. An environmental permit was issued for rehabilitation of the landfill. The decision and environmental permit prescribed groundwater quality monitoring. Prior to these documents, five piezometers were placed into operation in 1991. The objective of this paper is to determine the potential differences in ground and surface water quality that may have resulted from landfill operations, effectiveness of the rehabilitation efforts, and the potential risk of contamination of the Ivanščak water well. The results of the research were subjected to statistical analyses (e.g., T-test and ANOVA). Based on the regional flow model, a numerical groundwater flow model and contamination transport model were created, which provided scenarios for the potential spread of pollution from the Piškornica landfill while considering different water well operation regimes. It was concluded that a) even though rehabilitation has not been completed, the groundwater quality status improved and b) none of the analysed real flow scenarios generated redirection of streamline patterns towards the Ivanščak water well. Considering future development and likely increase of the Ivanščak well capacity, the expansion of monitoring was proposed for additional measuring locations