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Number of results: 88
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Abstract

The article presents research results of the strength parameters of HPC achieved in various research conditions. The research was carried out on substantially different samples, both as to the size as the slenderness ratio. Moreover, the assessment of the effect of speed of a load on strength parameters as well as other factors which in a significant way show the difference in the strength values was made. For comparison, the results were also applied to the relations known in ordinary concrete.
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Abstract

The aim of this study was to evaluate the influence of the newly isolated Lactobacillus plantarum LUHS135 and Lactobacillus paracasei LUHS244 strains grown in potato juice (with a cell count of 8.0-9.0 log10 CFU/ml) on the blood and faeces parameters of exercising horses. The horses were classified into four different groups: a control group (which received no probiotics); the first group (which received 200 ml of L. plantarum culture in potato juice); the second group (which received 200 ml of L. paracasei culture in potato juice); and the third group (which received an L. plantarum and L. paracasei mix (with the mix consisting of 100 ml of each). Indices for the blood and faeces microflora were obtained before and after treatment of horses (on days zero and thirty). It was observed that the count for lactic acid bacteria (LAB) in the faeces was significantly higher on day thirty, whereas it was lower when it came to the total enterobacteria count (TCE). Despite the ambiguous influence of any treatment on blood parameters, the L. plantarum × L. paracasei mixture increased the concentration of HGB and O2 saturation in blood samples which were taken from the horses. L. paracasei significantly decreased the lactate concentration levels in horse blood samples. As a result of the present study, it can clearly be seen that the strains being used revealed their potential application as probiotics; however, further studies are required to prove the survival and action mechanisms of the newly isolated strains.
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Abstract

The underground mining of coal deposits in the Upper Silesian Coal Basin (GZW) re-sults in an imbalance in the distribution of the stress in the rock mass, both in the immediate and distant surroundings of mining excavations. The occurrence of seismic tremors, among others, is the consequence of this process,. The intensities of seismic phenomena, which occur in several regions of the GZW (Bytomian Basin, Main Saddle, Main Basin, Kazimierzowska Basin, and the Jejkowice Basin) are very diverse, ranging from tremors unrecognizable by humans to strong tremors of the nature of weak earthquakes (Patyńska and Stec 2017). During the period of 15 years, i.e. from 2001 to 2015, the level of seismic activity changed and de-pended on both the intensity of the excavation work and the variability of the lithological and tectonic structures. On the other hand, the seismic activity analysis has shown that in recent years, despite a decrease in total output, seismic activity and rockburst hazard have increased. One of the rea-sons was the increase in mining output. Almost half of the output came from coal seams under the rockburst hazard. This resulted in an increase in the number of great energy tremors with the energy of 107, 108 and 109 J. It has been shown that the amount of energy tremors has a high impact on the level of the rockburst hazard. Between 2001 and 2015, as many as 20 rockburst were caused by seismic tremors above 107 J with 42 total phenomena (Patyńska 2002–2016). The purpose of characterizing the causes of this phenomenon was determined by the parameters characterizing the structure of the rock mass in places where the rockburst was recorded.
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Abstract

The normotensive (Wistar) and spontaneously hypertensive (SHR) rats were examined to assess the response of the organism to selenium (Se) overdose. Moreover, the effect of zinc (Zn) and vitamin E, i.e. dietary components interacting in many biochemical processes with Se, on the Se uptake was evaluated. The control group was fed an untreated diet, and the diets of two other groups were overdosed with Se in the form of sodium selenite (9 mg/kg) and supplemented with Zn (13 mg/kg). Two experimental groups were fed a diet supplemented with Zn (13 mg/kg) and Se at an adequate level (0.009 mg/kg); a half of the animals was supplemented with vitamin E. The results showed significant differences in the Se contents between the rat strains in case of Se-overdosed groups, where in the liver and kidney tissue Se contents of SHR rats exceeded 3- and 7-fold the normotensive ones. The Se uptake was altered by the vitamin E; no effect of Zn was observed. Activities of antioxidant enzymes were determined in the animal tissues indicating different patterns according to rat strain, tissue analysed, and administered Se dose. Thus, Se overdose, for instance, via an incorrectly prepared dietary supplement, can result in serious imbalances of the biochemical status of the animals.
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Abstract

The basis for a mineral deposit delimitation is a qualitative and quantitative assessment of deposit parameters, qualifying a deposit as an economically valuable object. A conventional approach to the mineral deposit recognition and a deposit detailed parameters qualification in the initial stages of development work in the KGHM were presented in the paper. The goals of such recognition were defined, which through a gradual detailed expansion, resulting from the information inflow, allows for the construction of a more complete decision-making model. The description of the deposit parameters proposed in the article in the context of fuzzy logic, enables a presentation of imprecise statements and data, which may be a complement to a traditional description. Selected non-adjustable and adjustable s-norm and t-norm operators were demonstrated. Operators effects were tested for selected ore quality parameters (copper content and deposit thickness) by constructing adequate membership functions. In a practical application, the use of chosen fuzzy logic operators is proposed for the assessment of the qualitative parameters of copper-silver ore in the exploitation blocks for one of the mines belonging to KGHM Polish Copper S.A. The considerations have been extended by including the possibility of using compensation operators.
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Abstract

The operational mineral deposit reconnaissance tends to evaluate its parameters to conduct safe and profitable production. Particular deposit parameters, important from the point of mineral deposit management, are estimated on the basis of observations carried out by mining geological surveys. These observations usually involve sampling, drilling, laboratory analyses and others. The use of fuzzy description to assess the parameters of the mineral deposit was proposed in the paper. In the fuzzy characteristics, an imprecise descriptive description appeared in place of a particular numerical quantity. This approach was used to description of the ore deposit features (metal content, volume, and metal yield) by assigning them specific characteristic functions, whose distributions were based on basic statistical quantities. Characteristic functions can be used to prepare operational strategies for any configuration of required deposit parameters resulting from the production management needs. For this purpose, selected logical operators of fuzzy sets were used. In the next approach to fuzzy modeling, an opportunity to characterize the deposit in a subjective approach was indicated, where the assessment of the deposit parameters is based on rough, in some way, discretionary observation and evaluation. Such model construction enabled the overall assessment of the deposit from the point of view of any parameters. Through the implementation of appropriate inference rules, adequate fuzzy control planes were obtained, which may also be useful in the context of operational mine strategy planning.
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Abstract

The paper analyses the possibilities of treating the ignition cable in the internal combustion engine as a distributed parameter system. It presents the experimental verification of computer simulations of signal propagation generated by ignition systems in the ignition cables, modelled by the distributed parameter system. The tests conducted to determine the wave parameters of ignition cables, as well as the results of numerical simulations and their experimental verifications, are presented. It is concluded that the modelling of the ignition cable by means of a long line gives positive results that can be used for the design of a spark plug with impedance equal to wave impedance of the ignition cable.
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Abstract

In this paper a mathematical model enabling the analysis of the heat-flow phenomena occurring in the waterwalls of the combustion chambers of the boilers for supercritical parameters is proposed. It is a one-dimensional model with distributed parameters based on the solution of equations describing the conservation laws of mass, momentum, and energy. The purpose of the numerical calculations is to determine the distributions of the fluid enthalpy and the temperature of the waterwall pipes. This temperature should not exceed the calculation temperature for particular category of steel. The derived differential equations are solved using two methods: with the use of the implicit difference scheme, in which the mesh with regular nodes was applied, and using the Runge-Kutta method. The temperature distribution of the waterwall pipes is determined using the CFD. All thermophysical properties of the fluid and waterwall pipes are computed in real-time. The time-spatial heat transfer coefficient distribution is also computed in the on-line mode. The heat calculations for the combustion chamber are carried out with the use of the zone method, thus the thermal load distribution of the waterwalls is known. The time needed for the computations is of great importance when taking into consideration calculations carried out in the on-line mode. A correctly solved one-dimensional model ensures the appropriately short computational time.
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Abstract

The paper is focused on properties testing of materials used in form of iso-exo sleeves for risers in ferrous alloys foundry. They are grainyfibrous materials, containing components which initiate and upkeep exothermic reaction. Thermo-physical parameters characterizing such sleeves are necessary also to fill in reliable databases for computer simulation of processes in the casting-mould layout. Studies with use of a liquid alloy, especially regarding different sleeves bring valuable results, but are also relatively expensive and require longer test preparation time. A simplified method of study in laboratory conditions was proposed, in a furnace heated to a temperature above ignition temperature of sleeve material (initiation of exothermic reaction). This method allows to determine the basic parameters of each new sleeve supplied to foundries and assures relatively quick evaluation of sleeve quality, by comparison with previous sleeve supplies or with sleeves brought by new providers.
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Abstract

This article presents a review of the investigation of the possibility of increasing the efficiency of existing line test solutions for troubleshooting testing for IPTV over xDSL, by the results of experimental research on real system under commercial exploitation. At the beginning of this article the main weaknesses of the existing troubleshooting testing are described. In the continuation of the article the physical layer parameters of xDSL transceiver are listed. This article also provides a few specific examples of xDSL lines with their physical layer parameters of xDSL transceivers followed by analysis how they can be used for the purposes of more efficient measurement of parameters of copper pairs.
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Abstract

The petrographic composition of coal has a significant impact on its technological and sorption properties. That composition is most frequently determined by means of microscope quantitative analyses. Thus, aside from the purely scientific aspect, such measurements have an important practical application in the industrial usage of coal, as well as in issues related to the safety in underground mining facilities. The article discusses research aiming at analyzing the usefulness of selected parameters of a digital image description in the process of automatic identification of macerals of the inertinite group using neural networks. The description of the investigated images was based on statistical parameters determined on the basis of a histogram and co-occurrence matrix (Haralick parameters). Each of the studied macerals was described by means of a 20-element feature vector. An analysis of its principal components (PCA) was conducted, along with establishing the relationship between the number of the applied components and the effectiveness of the MLP network. Based on that, the optimum number of input variables for the investigated classification task was chosen, which resulted in reduction of the size of the network’s hidden layer. As part of the discussed research, the authors also analyzed the process of classification of macerals of the inertinite group using an algorithm based on a group of MLP networks, where each network possessed one output. As a result, average recognition effectiveness of 80.9% was obtained for a single MLP network, and of 93.6% for a group of neural networks. The obtained results indicate that it is possible to use the proposed methodology as a tool supporting microscopic analyses of coal.
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Abstract

In this paper, we present the methods to detect the channel delay profile and the Doppler spectrum of shallow underwater acoustic channels (SUAC). In our channel sounding methods, a short impulse in form of a sinusoid function is successively sent out from the transmitter to estimated the channel impulse response (CIR). A bandpass filter is applied to eliminate the interference from out-of-band (OOB). A threshould is utilized to obtain the maximum time delay of the CIR. Multipath components of the SUAC are specified by correlating the received signals with the transmitted sounding pulse with its shifted phases from 0 to 2#25;. We show the measured channel parameters, which have been carried out in some lakes in Hanoi. The measured results illustrate that the channel is frequency selective for a narrow band transmission. The Doppler spectrum can be obtained by taking the Fourier transform of the time correlation of the measured channel transfer function. We have shown that, the theoretical maximum Doppler frequency fits well to that one obtained from measurement results.
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Abstract

Eye fluids (aqueous humour and vitreous humour) may be helpful in estimating ante-mortem blood levels, since some parameters measured in these fluids have proved to be stable or to change in a predictable way after death. This would help in diagnosing the cause of death in some diseases or to evaluate ante-mortem blood levels in certain animals not easy to handle or with difficult access. In order to establish reference values of some parameters in blood and eye fluids (aqueous humour and vitreous humour), as well as the possible correlation among these three different fluids, various minerals and electrolytes (Ca, P, Mg, K, Na, Fe, Cr, Co, Ni, Cu, Zn, Se and Mo) were measured in 15 four to five year-old Lidia bulls, all dying after a period of significant stress and major exertion. Plasmatic values of Mg and P were much greater than reported in the literature. In general, mineral plasmatic values were greater than those found in ocular fluids (aqueous and vitreous), while Na, K and Cr were similar in the three fluids. We have verified the existence of correlations in P, Co and Mo among the three fluids measured, and between Se of plasma and vitreous humour. But the most marked correlations were observed in Mo (plasma -aqueous humour, r = 0.893, plasma-vitreous humour, r = 0.945, HA -HV, r = 0.849), in P (plasma-vitreous humour, r = 0.726) and in Co (plasma-vitreous humour, r = 879).
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Abstract

Specific requirements are designed and implemented in electronic and telecommunication systems for received signals, especially high-frequency ones, to examine and control the signal radiation. However, as a serious drawback, no special requirements are considered for the transmitted signals from a subsystem. Different industries have always been struggling with electromagnetic interferences affecting their electronic and telecommunication systems and imposing significant costs. It is thus necessary to specifically investigate this problem as every device is continuously exposed to interferences. Signal processing allows for the decomposition of a signal to its different components to simulate each component. Radiation control has its specific complexities in systems, requiring necessary measures from the very beginning of the design. This study attempted to determine the highest radiation from a subsystem by estimating the radiation fields. The study goal was to investigate the level of radiations received and transmitted from the adjacent systems, respectively, and present methods for control and eliminate the existing radiations. The proposed approach employs an algorithm which is based on multi-component signals, defect, and the radiation shield used in the subsystem. The algorithm flowchart focuses on the separation and of signal components and electromagnetic interference reduction. In this algorithm, the detection process is carried out at the bounds of each component, after which the separation process is performed in the vicinity of the different bounds. The proposed method works based on the Fourier transform of impulse functions for signal components decomposition that was employed to develop an algorithm for separation of the components of the signals input to the subsystem.
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Abstract

A transformer is an important part of power transmission and transformation equipment. Once a fault occurs, it may cause a large-scale power outage. The safety of the transformer is related to the safe and stable operation of the power system. Aiming at the problem that the diagnosis result of transformer fault diagnosis method is not ideal and the model is unstable, a transformer fault diagnosis model based on improved particle swarm optimization online sequence extreme learning machine (IPSO-OS-ELM) algorithm is proposed. The improved particle swarmoptimization algorithm is applied to the transformer fault diagnosis model based on the OS-ELM, and the problems of randomly selecting parameters in the hidden layer of the OS-ELM and its network output not stable enough, are solved by optimization. Finally, the effectiveness of the improved fault diagnosis model in improving the accuracy is verified by simulation experiments.
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Abstract

The paper presents the correlation between the CRI (Coke Reactivity Index), CSR (Coke Strength after Reaction) and the remaining 36 quality parameters of coking coal from the Pniówek deposit (SW part of the USCB). The test results were obtained for a region of fundamental importance to the Polish reserves of coking coal, characterized by highly variable coalification and quality parameters. The tests related to the determination of relationships of the CRI and CSR indices to other parameters were based on 25 channel samples acquired from active workings. The characteristics of the variability of the CRI and CSR indices were analyzed using statistical methods. The dependencies between the CRI and CSR indices and the parameters having an impact on their values were determined using linear correlation. An attempt was also made to determine the correlations between the concerned parameters using the multiple correlation method. The obtained results have been presented and compared to the results of globally conducted experiments in the form of charts presented by (North et al. 2018b). No clear dependence of the CRI and CSR indices was exhibited in case of most of the analyzed quality parameters, which is supported by low correlation coefficients of r < 0.5. The statistical analysis exhibited only 9 cases of correlation between CRI and CSR with other quality parameters, where the correlation coefficient was r ≥ 0.5, that is: Ht a, Na2O, Al2O3 and SiO2, Mn3O4, da a and dr a. This confirms the different characteristics of coal from the studied area, exhibited multiple times, that should be related to the specific coalification process, especially the occurrence of thermal metamorphism.
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Abstract

Clethodim herbicide (Cle) and three Trichoderma strains (Tri) were applied either alone or in combination (Cle + Tri) for controlling weeds, root knot nematodes (Meloidogyne arenaria) and Rhizoctonia root rot disease (Rhizoctonia solani) as well as for evaluating their effects on total microbial count in the rhizosphere and the number of Rhizobium nodules on roots in two faba bean cultivars cultivated in naturally heavily infested fields. The evaluated characters were very similar for the two tested cultivars (Nubariya 1 and Sakha 3). Treatment with Cle alone highly reduced the fresh and dry matter of tested weeds (Amaranthus viridis, Cynodon dactylon and Cenchrus ciliaris), followed by Cle + Tri and Tri alone. Cle + Tri highly reduced nematode parameters viz. numbers of J2 in soil or roots, females, eggs, galls and egg-masses when compared with each treatment alone. Tri alone caused a great decrease in Rhizoctonia root rot infection, followed by Cle + Tri and Cle alone. Total microbial count and Rhizobium nodules were affected only with Cle treatment. Plant growth parameters (shoot length, shoot fresh and dry weight and numbers of branches and leaves) and yield parameters (fresh pod and dry weight, seed number per pod, seed weight and ash pod weight of plant) were greatly improved for Cle + Tri treatments when compared with either Tri or Cle alone.
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Abstract

The effect of monoterpenoid 1,8-cineol on the toxicity and physiology of elm leaf beetle, Xanthogaleruca luteola Müller under laboratory conditions (26 ± 1°C, 65 ± 10% RH and 16L : 8D h) was investigated. Initially, LC30 and LC50 values of the constituent were estimated to be 23.5 ppm and 31.9 ppm for the last instar larvae after 48 h, respectively. Significant changes were observed in the values of relative growth rate (RGR), efficiency of conversion of ingested food (ECI), efficiency of conversion of digested food (ECD), approximate digestibility (AD) and consumption index (CI) between control and treated larvae with 1,8-cineol. The amounts of protein, glucose and urea decreased in the treated larvae in comparison with control. Similar findings were observed in the activities of alkaline phosphatase and lactate dehydrogenase while the activities of glutathione S-transferase and esterase significantly increased in the treated larvae using CDNB and α-naphtyl acetates as the substrates. Morphological and histological changes brought about by 1,8-cineol in the present study are indicative of growth inhibition targeting specific organs such as those of reproduction. We believe that 1,8-cineol can be considered as a safe and environmentally friendly compound.
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Abstract

The paper presents application of a modified, symmetrical Bouc-Wen model to simulate the mechanical behaviour of high-frequency piezoelectric actuators (PAs). In order to identify parameters of the model, a two-step algorithm was developed. In its first stage, the mechanical parameters were identified by taking into account their bilinear variability and using a square input voltage waveform. In the second step, the hysteresis parameters were determined based on a periodic excitation. Additionally, in order to reduce the influence of measurement errors in determination of selected derivatives the continuum wavelet transform (CWT) and translation-rotation transformation (TRT) methods were applied. The results proved that the modified symmetrical Bouc-Wen model is able to describe the mechanical behaviour of PAs across a wide frequency range.
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Abstract

This is an extended research of the paper (Islam et al., 2011) conducted to obtain a universal set of interaction parameters of the model NRTL over the temperature range 10 - 100 °C for hexane-butanol-water system; meaning for binary pairs hexane-butanol, butanol-water and hexane-water; and for ternary system hexane-butanol-water. Thorough investigations of data selections for all binary pairs (Vapor-Liquid Equilibrium (VLE), Liquid-Liquid Equilibrium (LLE)), infinite dilution activity coefficient (γ∞), infinite dilution distribution coefficient (Dsw), excess enthalpy (HE), and for ternary system (LLE of hexane-butanol-water) were carried out. Finally quadratic temperature dependent interaction parameters were estimated regressing all the mentioned data and in each case calculated results were compared with literature values. The comparisons showed an overall percentage of error within 15% for the mentioned phase equilibrium calculations.
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Abstract

In the paper, the variation of the intensity of the geomagnetic field force is analysed in time and space. For the research, the data from measurements of the intensity of the geomagnetic field force at four airports (Kaunas, Klaip˙eda, Palanga andVilnius) and 6 geomagnetic field repeat stations aswell as the data from Belsk Magnetometric Observatory (Poland) were used. For the data analysis, the theory of covariance functions was applied. The estimates of the cross-covariance functions of the measured intensity of the geomagnetic field force or the estimates of auto-covariance functions of single data were calculated according to the random functions created from the force intensity measurement data arrays. The estimates of covariance functions were calculated upon varying the quantization interval on the time scale and applying the software created using Matlab package of procedures. The impact of radars of airports on the intensity of geomagnetic field variation and on changes of their covariance functions was established.
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Abstract

The paper presents a proposal of using additional statistical parameters such as: standard deviation, variance, maximum and minimum increases of the observed value that were determined during measurements of temperature fields created on the surface of the tested electrochemical capacitor. The measurements were carried out using thermographic methods in order to support assessment of the condition of electrochemical capacitor under classic durability tests based on methods of determination of capacity and equivalent series resistance. The possibility of using some statistical parameters in assessment of the electrochemical capacitor quality was illustrated. The applied measurement methodology and the results of research associated with the classic methods of supercapacitors’ assessment are presented. The obtained results indicate that the variability of some statistical parameters of temperature fields can be directly related to changing the values of standard parameters describing electrochemical capacitor, which are capacitance and equivalent series resistance.
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Abstract

Today, a cascaded system of position loop, velocity loop and current loop is standard in industrial motion controllers. The exact knowledge of significant parameters in the loops is the basis for the tuning of the servo controllers. A new method to support the commissioning has been developed. It enables the user to identify the moment of inertia as well as the time constant of the closed current loop simultaneously. The method is based on the auto relay feedback experiment by Aström and Hägglund. The model parameters are automatically adjusted according to the time behaviour of the controlled system. For this purpose, the auto relay feedback experiment is combined with the technique of gradual pole compensation. In comparison to other existing methods, this approach has the advantage that a parametric model for the open velocity loop is derived directly.
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Abstract

The paper presents an adapted least squares identification method for reduced-order parametric models. On the example of the open velocity loop, different model approaches were implemented in a motion control system. Furthermore, it is demonstrated how the accuracy of the method can be improved. Finally, experimental results are shown.
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