Individual System Parameters Research Articles

Analytical prediction of temperature effects on Lamb wave response in smart plates and its experimental verification

Abstract This article examines the effectiveness of a recently developed theoretical model for the generation and sensing of Lamb waves in thin plates with surface-bonded piezoelectric transducers in predicting temperature effects on Lamb waves and their time reversibility. In particular, the analytical model provides a closed-form solution, which incorporates both the shear-lag effect of the bonding layer and the system inertia in transducer-plate interaction modeling. Temperature-dependent material properties and thermal expansion of the system constituents are considered to predict the Lamb wave signal under a thermal environment. The accuracy of the theoretical prediction is assessed in comparison with experimental results obtained using an aluminum plate with adhesively bonded lead zirconate titanate transducers to its surface at different system temperatures ranging from 20°C to 75°C. Comparison is also made with experimental data and analytical solutions presented earlier without considering the inertia effect. The study reveals that the current solution accurately predicts the change in Lamb wave signal due to temperature variation, including the frequency dependency of the peak amplitude change with temperature rise. However, the theoretical model fails to predict the experimental trends when the inertia terms are neglected. The current model is also used to study the contributions of individual system parameters to the overall temperature effect on the time reversibility of Lamb waves and its dependence on the excitation frequency.

Studying the influence of transport model parameters on the results of passenger traffic calculations (using the case of St. Petersburg)

This study focuses on the development of mathematical modelling methods for transport and urban planning. The current research focuses on an innovative mathematical model for simultaneous calculation of passenger and transport flow intensity in urban agglomerations using a common transport graph. An assessment of the model limitation impact on the parameters of individual and public transportation systems in a city (urban agglomeration) is conducted. To verify the model, several experimental calculations are performed for the transport system of the St. Petersburg agglomeration. The model presented by the authors can be used in scientific research in urban and transport planning and in the development of design solutions in cities.

Simulation of a Direct Time-of-Flight LiDAR-System

The simulation of a direct time-of-flight flash LiDAR system is crucial for the assessment of the system performance during sensor development. However, due to the number of components of the LiDAR system and the optical signal path and their parameter uncertainty, simulation models often are difficult to validate. In this paper a simulation model is proposed, which extends statistical simulation of the direct time-of-flight method and incorporates different sensor characteristics. Based on a poisson process with a subsequent Monte Carlo simulation various detector types are implemented to examine the detection behaviour during prototype construction. The detector types considered here include the SPAD, the SPAD array, the SiPM and the SiPM array. These are simulated in interaction with a LiDAR system, which in addition to the sensor consists of the emitter, signal path, object and receiver optics modules. Each of them is defined by several individual system parameters. After derivating the photon detection rate the implementation of the detector specific parameters such as dead time, afterpulsing, crosstalk and threshold are considered in more detail. Non-ideal tunings during prototyping, which are accompanied by the consideration of the pulse shape, the illuminated/observed object area as well as the actually used detector area are also taken into account.

Dynamic Self-Triggered Impulsive Synchronization of Complex Networks With Mismatched Parameters and Distributed Delay.

Synchronization of complex networks with nonlinear couplings and distributed time-varying delays is investigated in this article. Since the mismatched parameters of individual systems, a kind of leader-following quasisynchronization issues is analyzed via impulsive control. To acquire appropriate impulsive intervals, the dynamic self-triggered impulsive controller is devoted to predicting the available instants of impulsive inputs. The proposed controller ensures the control effects while reducing the control costs. In addition, the updating laws of the dynamic parameter is settled in consideration of error bounds to adapt to the quasisynchronization. With the utilization of the Lyapunov stability theorem, comparison method, and the definition of average impulsive interval, sufficient conditions for realizing the synchronization within a specific bound are derived. Moreover, with the definition of average impulsive gain, the parameter variation scheme is extended from the fixed impulsive effects case to the time-varying impulsive effects case. Finally, three numerical examples are given to show the effectiveness and the superiority of proposed mathematical deduction.

WAYS OF IMPROVING THE VERTICAL LAYER APPARATUS FOR PROCESSING LIQUID PIG MANURE

Technologies for processing (manure processing) manure depend on the system and method of keeping animals. This is due to the physical properties of the obtained manure, primarily its moisture content. By using litter, solid (litter) manure is obtained, which has a moisture content of 60...80%. If litter is not used when keeping pigs, then manure without litter is obtained, which is divided into two groups by moisture content: solid (60-80%) and liquid (82-98%). Vortex layer devices are equipped with different types of working bodies and layout of the working area. When carrying out liquid-phase processes, using ferromagnetic elements as a working body, trap screens or labyrinths designed to keep ferromagnetic particles in the working area can be installed on the ends of the non-magnetic insert (or only at the outlet). Grinding and mixing can occur not only with the help of ferromagnetic particles, but also with the help of knives, tubes or a rotor. In these cases, the sieves act as filters (separators). Ferromagnetic elements are added to the working area using an electromagnetic dispenser. Analyzing the results of previous scientific studies, it can be stated that increasing the efficiency of the vortex layer devices is proposed due to the improvement of the design or the substantiation of the structural and technological parameters of individual systems, without taking into account their interconnection. It should be noted that most of the obtained results from the substantiation of structural and technological parameters are experimental and do not have a theoretical justification. In order to solve the problems, the structural and technological scheme of the vortex layer apparatus for liquid manure processing, which allows to obtain liquid organic fertilizers of high quality with increased productivity and level of automation, is substantiated.

COVID-19 case fatality rate in the context of healthcare system organization and EHCI performance: Focus on the Visegrad (V4) countries

Abstract This article tries to explain the differences in COVID-19 case fatality rate (CFR) in 22 European countries by their type of organization and performance level of their healthcare systems. The CFR is taken here as the most important indicator since it measures the ratio between COVID deaths and COVID cases. In our view, this indicator reflects the true performance of the healthcare system, as this indicator is freed form public health interventions, like testing, lockdowns or social distancing. Our research is also unique, because it sees the healthcare system in a holistic way and tries to explain the CFR not by individual risk factors, socioeconomic indicators, or partial system parameters, but by using a complex healthcare system classification method adopted from Isabelle Joumard and an overall healthcare system performance index adopted from European Health Consumer Index (EHCI). The main results are twofold. First, higher EHCI score is related to lower CFR. So, the countries are cumulated basically in two quadrants: High EHCI performers (score 790 and higher) with low CFR (below 1.93%) and low EHCI performers with high COVID CFR. Second, apart from Czech Republic, the V4 countries are not doing very well in fighting COVID. Hungary is the worst, not only from the V4 group, but the worst from the whole list of 22 European countries included in this research. Poland is doing better, but still is high above the median CFR. Slovakia was the second worst from the V4 group. Czech Republic is the best V4 performer and the only country with EHCI score lower than median and CFR also lower than the median.

USING OF THE MATHEMATICAL APPARATUS REGRESSION ANALYSIS TO UNIFY THE CALCULATING METHODOLOGY FOR THE T-64B TANK'S OVERHAUL LIFE

The subject matter of the article is the life cycle of a T-64B tank sample during the period from normal operation in a combat training group to resource consumption and carrying out average and capital repairs. The goal of the study is to develop a model of dependence of inter-repair service life of the T-64B tank sample on the machine operating conditions and, on its basis, a methodology for controlling the parameters of individual assemblies and systems of the tank sample during its life cycle. The tasks to be solved are: to analyze the results of statistical records of tank system failures and damages number and identify the predicates set affect the inter-repair service life of the machine depending on conditions of its tasks for the intended purposes; to create the regression equation for getting the unified analytical dependence of inter-repair service life of the T-64B tank sample in the period from normal operation in training and combat group to service life and overhaul; to investigate specific influence of reliability indices on the machine's service life. General scientific and special methods of scientific knowledge are used. The method of hierarchy analysis, mathematical apparatus of probability theory and multidimensional statistical analysis were used. The following results are obtained. A set of predicates influence the inter-repair service life of the machine depending on conditions of its tasks for the intended purposes fulfillment has been determined. A regression equation has been drawn up to obtain a unified analytical dependence of the overhaul life of a T-64B tank sample during the period from normal operation in a combat training group to the development of a resource and carrying out of intermediate and complete overhauls were drawn up. Engineering solutions have been proposed to implement a methodology for monitoring the parameters of individual units and systems of the tank sample during its life cycle, namely integrated real-time monitoring of oil condition and recording of engine operating hours under various load conditions. Conclusions. The space of features characterizes the conditions of the tank sample tasks for its intended purposes, includes service life, crew training, operation, seasonality of the unit’s performed tasks nature, machine operating time since the last service and range of the vehicle before the next overhaul. The analytical relationship between the individual factors determining the conditions under which the T-64B tank sample performs its tasks for the intended purposes and the machine's service life consumption as a dependent variable can be determined in the form of a regression equation. Differentiated control of the parameters of individual assembly units and systems of the tank sample plays a leading role in ensuring the combat readiness and efficiency of the use of aging samples of weapons, insures personnel against possible accidents and catastrophes, sudden failures.

Analysis of Prefabricated Systems in the Construction of Family Houses

At the moment the human is trying to make the construction as efficient as possible, accelerate and facilitate the introduction of different types of innovations. Therefore, to the fore a new concept of prefabrication, which we call modern methods of construction MMC is coming. In this article, 3 prefabricated construction systems were chosen for the analysis of the construction of the family house. It is a system of Europanel SIP technology, CLT panels and ceramic panels. These are systems of euro panels' technology SIP, CLT panels and ceramic panels. The choice of construction systems has taken into account that all three systems fall under the MMC philosophy. Subsequently, selected parameters of individual structural systems were analysed, such as wall thickness, ceiling thickness, bulk density, compressive strength of walls, heat transfer coefficient, reaction to fire, fire resistance, usable area and price on a particular family house project.

Analytical assessment of restraint forces and crack widths in end-restrained building slabs

This paper deals with the analytical assessment of restraint forces and crack widths in end-restrained building slabs. The analysis concentrates on the service limit state (SLS) and the challenge is hereby the appropriate consideration of the combined effect of axial restraint due to imposed deformations and bending cracking due to loading. As for the imposed deformations, the paper regards the drying shrinkage of concrete under indoor conditions, although any other temperature deformation or combination of shrinkage and temperature could be included accordingly.A deformation-based approach is presented, in which imposed deformations are made compatible with the released deformations of the slab due to opening of loading-induced bending cracks. The solution aims an appropriate inclusion of the most relevant effects while still providing a practicable and verifiable solution for the complex problem of assessing the restraint forces as well as the crack widths in end-restrained building slabs.The result of this approach is an analytical quantification of restraint forces to be transferred in the restraining members. In addition, the presented approach enables the determination of crack widths in the restrained conditions. An important asset of the analytical nature of this approach is the explicit correlation between individual system parameters, especially concrete properties and surrounding conditions, member dimensions and provided reinforcement, loading in the SLS and restraining condition.The paper includes the presentation of the general idea of a deformation-based assessment of end-restrained building slabs; the demonstration of this approach with an example from the literature; and the comparison of the analytical design solution with experimental results on the combined effect of bending and axial restraint in slab-like specimens.

Design and Evaluation of a Compact Harmonic Transponder for Insect Tracking

Passive harmonic transponders are used in applications where weight and size restrictions are prohibitive to the use of active radio transmitters, e.g., for insect tracking. A typical harmonic transponder tag consists of a wire dipole antenna and a Schottky diode with a parallel inductance. Despite the simplicity in tag circuit, designing lightweight, compact, and efficient harmonic tags are challenging. In this letter, we describe a design that combines the reliability of a printed circuit with the simplicity and small mass of a wire dipole antenna. We study the interplay of individual system parameters and show that optimizing the tag antenna together with the tuning inductance provides further opportunities for tag miniaturization.

Methods for assessing road traffic accident risks with changes in transport demand structure in cities

The article describes the concept of road traffic accident (RTA) risk as a measure for assessing road traffic safety in the entire transport system of a large city. It considers methods for assessing RTA risks through the global operating parameters of individual transport systems in a city. A method to analyze statistical data on RTA causes in a large city is proposed for the subsequent assessment of the existing RTA risks. The article also presents functional relationships for assessing RTA risks as restrictions when forming efficient transport systems in cities.

Dynamic response analysis of structure with hybrid random and interval uncertainties

With the increasing complexity of uncertain parameters, the single uncertainty modeling is challenged for structures involving multiple types of uncertainties. However, in the contrast to research on static problems with hybrid uncertainties, dynamic mixed uncertainty problems have not been well addressed. A novel dynamic analysis of structure with hybrid uncertainties is developed for the expressions for the lower and upper bounds of the mean value and standard deviation of the dynamic response. Within this approach, interval variables are adopted to quantify the non-probabilistic uncertainty associated with objective limited information. Some other parameters are considered as random variables. Based on series expansion of random and interval quantities with respect to uncertain parameters, the proposed method evaluates the lower and upper bounds of the first- and second-order moments of the structure response through solving deterministic equations. This method is also capable to solve pure interval problems. Finally, numerical examples are analyzed to illustrate the feasibility and effectiveness of the proposed method. The influence on the structure response caused by the individual system parameters is also investigated.

Analysis of a rotordynamic system with anisotropy and nonlinearity using the Floquet theory and the method of normal forms

The system under analysis is composed of an asymmetric rotor, two asymmetric bearings and a nonlinear spring-damper system representing an annular gas seal. The anisotropy in the rotor stiffness introduces time-periodic coefficients in the equations of motion which lead to parametric excitation with the typical resonance effects. As the additional anisotropy in the bearings may increase the area of unsafe operation conditions, the impact of these two different sources of anisotropy on the stability of the trivial solution is investigated in detail by a numerical approach based on the Floquet theory. Further insight into the stability behavior in case of an unstable trivial solution is obtained by accounting for stiffness and damping nonlinearities due to the gas seal. In this nonlinear case, the stability of the periodic solutions is analyzed by the semi-analytical method of normal forms revealing the influence of individual system parameters. The results of the semi-analytical approximation are verified by numerical calculations showing good agreement.

Selection of filter parameters of Individual water supply systems

The paper is devoted to the problem of optimal design, construction and operation of water supply systems and their elements. The key element of the system is a water well. The quality of its design and construction determines the operation of the water intake as a whole. Disadvantages in the construction of a well lead to disruption of the entire water supply system of a particular object. The paper proposed a methodology for selecting the optimal diameter and length of the well filter of a water well. Based on the methodology, an example of filter parameters selection for hydrogeological conditions of the city of Kursk is given. The above calculation showed that the use of the entrance velocity criterion in the design of wells can significantly reduce the cost of well construction while ensuring the design flow rate and allowable lowering of the water level. The cost of the filter, depending on the well design, is 20-30% of the total price for its construction. The most important filter parameters affecting the cost of a well are its length and diameter. Justifying the minimum diameter of the filter that ensures the designed water intake and allowable dewatering can significantly reduce the cost of the well, taking into account the fact that modern pumping equipment allows the use of columns of small diameter above the filter.

Stochastic XFEM based fracture behavior and crack growth analysis of a plate with a hole emanating cracks under biaxial loading

In the paper, the stochastic fracture response of an isotropic finite plate with a circular hole emanating radial cracks, having different angles, under biaxial loading with different biaxiality ratio (β=0,1 and −1) is examined. In this direction, the mean values and corresponding coefficient of variations (COVs) of mixed mode stress intensity factor (MMSIFs) using the second order perturbation technique (SOPT) combined with a finite difference method through extended finite element method (XFEM) are evaluated in MATLAB environment. The random system parameters, e.g., normalized crack length, crack angle, the normalized radius of the hole, are assumed as uncorrelated input random variables. The effects, of these input parameters and biaxial load factors, on the statistics of MMSIFs with input individual and combined random system parameters, are analyzed. Also, the stochastic fracture behavior is predicted with the increment in the radius of the hole and with the change in the position of the discontinuities (a hole emanating cracks) in the plate using uncorrelated combined randomness with different input variables. Further, the static crack propagation behavior of the plate with hole emanating cracks under biaxial loading with different biaxiality ratio is analyzed.

Development of a self­diagnostics subsystem of the information­measuring system using anfis controllers

A hybrid self-diagnostic system was designed to evaluate correctness of functioning of sensors of the information-measuring system of testing hydraulic transmissions of diesel locomotives of UHP 750 type. The system features the possibility of checking certain four parameters in steady-state operation conditions using known mathematical dependencies. For the other 14 parameters (for which mathematical dependencies were not studied and which have a high complexity of calculations), 14 neural-fuzzy ANFIS networks were developed. Self-diagnostic algorithms using ANFIS controllers were elaborated. The algorithms provide prediction of individual system parameters with the help of ANFIS controllers and a further comparison of the predicted parameters with the measured parameters. The ANFIS controller structure with the proposed Sugeno rule set was constructed and its efficiency was shown. Network training and test of the diagnostic subsystem were performed using the data sets obtained in a series of tests of hydraulic transmissions conducted at Promteplovoz diesel locomotive repair plant. The test results have shown that application of the proposed procedure ensures obtaining of correct result of the self-diagnostic subsystem operation.

Inductive heating of glass fibre-reinforced thermoplastics using fibre- and wire-shaped stainless steel susceptors

This article deals with an experimental and numerical study of the inductive heating of glass fibre (GF)-reinforced thermoplastics with susceptors made of stainless steel that are embedded in them. The objective of this article is to examine the links between individual process and system parameters and the heating behaviour of fibre-reinforced plastics. Two different susceptor designs were tested in relation to their heating capability. Furthermore, it was possible to experimentally study the dependency of the space between the specimens and inductors and therefore the impact of the generator output of the induction system and inductor attachments differing in their geometric shapes in terms of heating. Moreover, it was possible to use numerical simulation to examine the heating behaviour at different frequencies. These findings indicate that it is possible to heat GF-reinforced semi-finished products by fibre-shaped susceptors. Finally, it was possible to demonstrate that the heating process can be designed by means of the frequency of the induction system and directly controlled using the generator output.

Modeling and Analysis of SiNW FET-Based Molecular Communication Receiver

Molecular Communication (MC) is a bio-inspired communication method based on the exchange of molecules for information transfer among nanoscale devices. MC has been extensively studied from various aspects in the literature; however, the physical design of MC transceiving units is largely neglected with the assumption that network nodes are entirely biological devices, e.g., engineered bacteria, which are intrinsically capable of receiving and transmitting molecular messages. However, the low information processing capacity of biological devices and the challenge to interface them with macroscale networks hinder the true application potential of nanonetworks. To overcome this problem, recently, we proposed a nanobioelectronic MC receiver architecture exploiting the nanoscale field effect transistor-based biosensor (bioFET) technology, which provides noninvasive and sensitive molecular detection while producing electrical signals as the output. In this paper, we introduce a comprehensive model for silicon nanowire (SiNW) FET-based MC receivers by integrating the underlying processes in MC and bioFET to provide a unified analysis framework. We derive closed-form expressions for noise statistics, signal-to-noise ratio (SNR) at the receiver output, and symbol error probability (SEP). Performance evaluation in terms of SNR and SEP reveals the effects of individual system parameters on the detection performance of the proposed MC receiver.

Modelling pathogen log10 reduction values achieved by activated sludge treatment using naïve and semi naïve Bayes network models

Risk management for wastewater treatment and reuse have led to growing interest in understanding and optimising pathogen reduction during biological treatment processes. However, modelling pathogen reduction is often limited by poor characterization of the relationships between variables and incomplete knowledge of removal mechanisms. The aim of this paper was to assess the applicability of Bayesian belief network models to represent associations between pathogen reduction, and operating conditions and monitoring parameters and predict AS performance. Naïve Bayes and semi-naïve Bayes networks were constructed from an activated sludge dataset including operating and monitoring parameters, and removal efficiencies for two pathogens (native Giardia lamblia and seeded Cryptosporidium parvum) and five native microbial indicators (F-RNA bacteriophage, Clostridium perfringens, Escherichia coli, coliforms and enterococci). First we defined the Bayesian network structures for the two pathogen log10 reduction values (LRVs) class nodes discretized into two states (< and ≥1 LRV) using two different learning algorithms. Eight metrics, such as Prediction Accuracy (PA) and Area Under the receiver operating Curve (AUC), provided a comparison of model prediction performance, certainty and goodness of fit. This comparison was used to select the optimum models. The optimum Tree Augmented naïve models predicted removal efficiency with high AUC when all system parameters were used simultaneously (AUCs for C. parvum and G. lamblia LRVs of 0.95 and 0.87 respectively). However, metrics for individual system parameters showed only the C. parvum model was reliable. By contrast individual parameters for G. lamblia LRV prediction typically obtained low AUC scores (AUC < 0.81). Useful predictors for C. parvum LRV included solids retention time, turbidity and total coliform LRV. The methodology developed appears applicable for predicting pathogen removal efficiency in water treatment systems generally.

Changes in Individual Drug-Independent System Parameters during Virtual Paediatric Pharmacokinetic Trials: Introducing Time-Varying Physiology into a Paediatric PBPK Model

Although both POPPK and physiologically based pharmacokinetic (PBPK) models can account for age and other covariates within a paediatric population, they generally do not account for real-time growth and maturation of the individuals through the time course of drug exposure; this may be significant in prolonged neonatal studies. The major objective of this study was to introduce age progression into a paediatric PBPK model, to allow for continuous updating of anatomical, physiological and biological processes in each individual subject over time. The Simcyp paediatric PBPK model simulator system parameters were reanalysed to assess the impact of re-defining the individual over the study period. A schedule for re-defining parameters within the Simcyp paediatric simulator, for each subject, over a prolonged study period, was devised to allow seamless prediction of pharmacokinetics (PK). The model was applied to predict concentration-time data from multiday studies on sildenafil and phenytoin performed in neonates. Among PBPK system parameters, CYP3A4 abundance was one of the fastest changing covariates and a 1-h re-sampling schedule was needed for babies below age 3.5 days in order to seamlessly predict PK (<5% change in abundance) with subject maturation. The re-sampling frequency decreased as age increased, reaching biweekly by 6 months of age. The PK of both sildenafil and phenytoin were predicted better at the end of a prolonged study period using the time varying vs fixed PBPK models. Paediatric PBPK models which account for time-varying system parameters during prolonged studies may provide more mechanistic PK predictions in neonates and infants.