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Abstract

This paper presents methods of separating the plateau part for various types of two-process profiles, having the traces of two processes. The traditional method based on the plateau-valley threshold, according to the ISO 13565-3 standard, is not always sufficient, since the valley portion can include plateau roughness. Starting and finishing points of each plateau in the measured profiles should be determined. The procedure found in the technical literature depends on setting not only the plateau-valley threshold but also a lower threshold. This approach was a little modified for profiles that contain both random and deterministic topography components. A new procedure of determination of the lower threshold was proposed for stratified profiles containing two deterministic parts. The valleys can be characterized by their widths and the distance between them. In addition, a description of the material probability curve is proposed.
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Abstract

Determination of the phase difference between two sinusoidal signals with noise components using samples of these signals is of interest in many measurement systems. The samples of signals are processed by one of many algorithms, such as 7PSF, UQDE and MSAL, to determine the phase difference. The phase difference result must be accompanied with estimation of the measurement uncertainty. The following issues are covered in this paper: the MSAL algorithm background, the ways of treating the bias influence on the phase difference result, comparison of results obtained by applying MSAL and the other mentioned algorithms to the same real signal samples, and evaluation of the uncertainty of the phase difference.
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Abstract

The paper presents theoretical and experimental analyses of a possible effect of the short-circuit forces on the transformer winding. The first part of the paper is focused on creation and activity of the radial and axial forces during a short circuit. It shows dimensions, direction and − of course − the resulting mechanical stress. The presented equation shows basic dependencies of these mechanical forces created in the transformer winding. Finally, the paper presents experimental methods of diagnosing and analysing the effects of short-circuit forces on the transformer winding.
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Abstract

The main aim of the study was to determine the goodness of fit between the relaxation function described with a rheological model and the real (experimental) relaxation curves obtained for digital materials fabricated with a Connex 350 printer using the PolyJet additive manufacturing technology. The study involved estimating the uncertainty of approximation of the parameters of the theoretical relaxation curve. The knowledge of digital materials is not yet sufficient; their properties are not so well-known as those of metallic alloys or plastics used as structural materials. Intensive research is thus required to find out more about their behavior in various conditions. From the calculation results, i.e. the uncertainty of approximation of the relaxation function parameters, it is evident that the experimental curves coincide with the curves obtained by means of the solid model when the approximation uncertainty is taken into account. This suggests that the assumed solid model is well-suited to describe a real material.
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Abstract

Analysis of the shape and location of abrasive grain tips as well as their changes during the grinding process, is the basis for forecasting the machining process results. This paper presents a methodology of using the watershed segmentation in identifying abrasive grains on the abrasive tool active surface. Some abrasive grain tips were selected to minimize the errors of detecting many tips on a single abrasive grain. The abrasive grains, singled out as a result of the watershed segmentation, were then analyzed to determine their geometric parameters. Moreover, the statistical parameters describing their locations on the abrasive tool active surface and the parameters characterizing intergranular spaces were determined.
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Abstract

Videoplethysmography is currently recognized as a promising noninvasive heart rate measurement method advantageous for ubiquitous monitoring of humans in natural living conditions. Although the method is considered for application in several areas including telemedicine, sports and assisted living, its dependence on lighting conditions and camera performance is still not investigated enough. In this paper we report on research of various image acquisition aspects including the lighting spectrum, frame rate and compression. In the experimental part, we recorded five video sequences in various lighting conditions (fluorescent artificial light, dim daylight, infrared light, incandescent light bulb) using a programmable frame rate camera and a pulse oximeter as the reference. For a video sequence-based heart rate measurement we implemented a pulse detection algorithm based on the power spectral density, estimated using Welch’s technique. The results showed that lighting conditions and selected video camera settings including compression and the sampling frequency influence the heart rate detection accuracy. The average heart rate error also varies from 0.35 beats per minute (bpm) for fluorescent light to 6.6 bpm for dim daylight.
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Abstract

Wireless Sensor Networks (WSNs) have existed for many years and had assimilated many interesting innovations. Advances in electronics, radio transceivers, processes of IC manufacturing and development of algorithms for operation of such networks now enable creating energy-efficient devices that provide practical levels of performance and a sufficient number of features. Environmental monitoring is one of the areas in which WSNs can be successfully used. At the same time this is a field where devices must either bring their own power reservoir, such as a battery, or scavenge energy locally from some natural phenomena. Improving the efficiency of energy harvesting methods reduces complexity of WSN structures. This survey is based on practical examples from the real world and provides an overview of state-of-the-art methods and techniques that are used to create energyefficient WSNs with energy harvesting.
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Abstract

Re-design of a given antenna structure for various substrates is a practically important issue yet non trivial, particularly for wideband and ultra-wideband antennas. In this work, a technique for expedited redesign of ultra-wideband antennas for various substrates is presented. The proposed approach is based on inverse surrogate modeling with the scaling model constructed for several reference designs that are optimized for selected values of the substrate permittivity. The surrogate is set up at the level of coarse-discretization EM simulation model of the antenna and, subsequently, corrected to provide prediction at the high-fidelity EM model level. The dimensions of the antenna scaled to any substrate permittivity within the region of validity of the surrogate are obtained instantly, without any additional EM simulation necessary. The proposed approach is demonstrated using an ultra-wideband monopole with the permittivity scaling range from 2.2 to 4.5. Numerical validation is supported by physical measurements of the fabricated prototypes of the re-designed antennas.
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Abstract

In this paper it is shown that M class PMU (Phasor Measurement Unit) reference model for phasor estimation recommended by the IEEE Standard C37.118.1 with the Amendment 1 is not compliant with the Standard. The reference filter preserves only the limits for TVE (total vector error), and exceeds FE (frequency error) and RFE (rate of frequency error) limits. As a remedy we propose new filters for phasor estimation for M class PMU that are fully compliant with the Standard requirements. The proposed filters are designed: 1) by the window method; 2) as flat-top windows; or as 3) optimal min-max filters. The results for all Standard compliance tests are presented, confirming good performance of the proposed filters. The proposed filters are fixed at the nominal frequency, i.e. frequency tracking and adaptive filter tuning are not required, therefore they are well suited for application in lowcost popular PMUs.
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Abstract

In this paper, a novel structure of a compact UWB slot antenna and its design optimization procedure has been presented. In order to achieve a sufficient number of degrees of freedom necessary to obtain a considerable size reduction rate, the slot is parameterized using spline curves. All antenna dimensions are simultaneously adjusted using numerical optimization procedures. The fundamental bottleneck here is a high cost of the electromagnetic (EM) simulation model of the structure that includes (for reliability) an SMA connector. Another problem is a large number of geometry parameters (nineteen). For the sake of computational efficiency, the optimization process is therefore performed using variable-fidelity EM simulations and surrogate-assisted algorithms. The optimization process is oriented towards explicit reduction of the antenna size and leads to a compact footprint of 199 mm2 as well as acceptable matching within the entire UWB band. The simulation results are validated using physical measurements of the fabricated antenna prototype.
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Abstract

The paper presents major issues associated with the problem of modelling change output accelerometers. The presented solutions are based on the weighted least squares (WLS) method using transformation of the complex frequency response of the sensors. The main assumptions of the WLS method and a mathematical model of charge output accelerometers are presented in first two sections of this paper. In the next sections applying the WLS method to estimation of the accelerometer model parameters is discussed and the associated uncertainties are determined. Finally, the results of modelling a PCB357B73 charge output accelerometer are analysed in the last section of this paper. All calculations were executed using the MathCad software program. The main stages of these calculations are presented in Appendices A−E.
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Abstract

Determining the size of source effect of a radiation thermometer is not an easy task and manufacturers of these thermometers usually do not indicate the deviation to the measured temperature due to this effect. It is one of the main uncertainty components when measuring with a radiation thermometer and it may lead to erroneous estimation of the actual temperature of the measured target. We present an empiric model to estimate the magnitude of deviation of the measured temperature with a long-wavelength infrared radiation thermometer due to the size of source effect. The deviation is calculated as a function of the field of view of the thermometer and the diameter of the radiating source. For thermometers whose field of view size at 90% power is approximately equal to the diameter of the radiating source, it was found that this effect may lead to deviations of the measured temperature of up to 6% at 200ºC and up to 14% at 500ºC. Calculations of the temperature deviation with the proposed model are performed as a function of temperature and as a function of the first order component of electrical signal.
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Abstract

Progress in UV treatment applications requires new compact and sensor constructions. In the paper a hybrid (organic-inorganic) rare-earth-based polymeric UV sensor construction is proposed. The efficient luminescence of poly(methyl) methacrylate (PMMA) matrix doped by europium was used for testing the optical sensor (optrode) construction. The europium complex assures effective luminescence in the visible range with well determined multi-peak spectrum emission enabling construction of the optrode. The fabricated UV optical fibre sensor was used for determination of Nd:YAG laser intensity measurements at the third harmonic (355 nm) in the radiation power range 5.0-34.0 mW. The multi-peak luminescence spectrum was used for optimization of the measurement formula. The composition of luminescent peak intensity enables to increase the slope of sensitivity up to −2.8 mW-1. The obtained results and advantages of the optical fibre construction enable to apply it in numerous UV detection systems.
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Abstract

This paper deals with wastewater treatment systems placed in motorway service areas (MSAs). In the years 2008-2009 eight of such facilities installed on the stretch of the A2 motorway between Poznań and Nowy Tomyśl were examined and analyzed. The system consists of a septic tank, a submerged aerated biofilter and an outflow filter. The volume of traffic on the highway was analyzed, the amount of water use was measured and peak factors were calculated. On this basis it was concluded that the inflows to the wastewater treatment systems in many cases exceeded the nominal design values. Based on the analysis of effluent quality it was found that the effects of plant operation in large part did not meet the requirements. It was found that the bioreactor aeration system and the design of the suspension separator (outflow filter) should be modified. One of the solutions was to use the soil-reed bed for wastewater treatment. The treatment of wastewater from the MSAs is a task that must take into account the unusual character of these facilities and the atypical quality of the effluent.
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Abstract

This paper studies the assessment of sensitivity to land degradation of Deliblato sands (the northern part of Serbia), as a special nature reserve. Sandy soils of Deliblato sands are highly sensitive to degradation (given their fragility), while the system of land use is regulated according to the law, consisting of three zones under protection. Based on the MEDALUS approach and the characteristics of the study area, four main factors were considered for evaluation: soil, climate, vegetation and management. Several indicators affecting the quality of each factor were identified. Each indicator was quantified according to its quality and given a weighting of between 1.0 and 2.0. ArcGIS 9 was utilized to analyze and prepare the layers of quality maps, using the geometric mean to integrate the individual indicator map. In turn, the geometric mean of all four quality indices was used to generate sensitivity of land degradation status map. Results showed that 56.26% of the area is classified as critical; 43.18% as fragile; 0.55% as potentially affected and 0.01% as not affected by degradation. The values of vegetation quality index, expressed as coverage, diversity of vegetation functions and management policy during the protection regime are clearly represented through correlation coefficient (0.87 and 0.47).
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Abstract

The influence of sewage sludge torrefaction temperature on fuel properties was investigated. Non-lignocellulosic waste thermal treatment experiment was conducted within 1 h residence time, under the following temperatures: 200, 220, 240, 260, 280 and 300°C. Sawdust was used as lignocellulosic reference material. The following parameters of biochar have been measured: moisture, higher heating value, ash content, volatile compounds and sulfur content. Sawdust biochar has been confirmed to be a good quality solid fuel. High ash and sulfur content may be an obstacle for biochar energy reuse. The best temperature profile for sawdust torrefaction and fuel production for 1 h residence time was 220°C. At this temperature the product contained 84% of initial energy while decreased the mass by 25%. The best temperature profile for sewage sludge was 240°C. The energy residue was 91% and the mass residue was 85%. Higher temperatures in both cases caused excessive mass and energy losses.
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Abstract

The paper considers an algorithm for increasing the accuracy of measuring systems operating on moving objects. The algorithm is based on the Kalman filter. It aims to provide a high measurement accuracy for the whole range of change of the measured quantity and the interference effects, as well as to eliminate the influence of a number of interference sources, each of which is of secondary importance but their total impact can cause a considerable distortion of the measuring signal. The algorithm is intended for gyro-free measuring systems. It is based on a model of the moving object dynamics. The mathematical model is developed in such a way that it enables to automatically adjust the algorithm parameters depending on the current state of measurement conditions. This makes possible to develop low-cost measuring systems with a high dynamic accuracy. The presented experimental results prove effectiveness of the proposed algorithm in terms of the dynamic accuracy of measuring systems of that type.
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Abstract

Electrochemical amperometric gas sensors represent a well-established and versatile type of devices with unique features: good sensitivity and stability, short response/recovery times, and low power consumption. These sensors operate at room temperature, and therefore have been applied in monitoring air pollutants and detection of toxic and hazardous gases in a number of areas. Some drawbacks of classical electrochemical sensors are overcome by the solid polymer electrolyte (SPE) based on ionic liquids. This work presents evaluation of an SPE-based amperometric sensor from the point of view of current fluctuations. The sensor is based on a novel three-electrode sensor platform with solid polymer electrolytes containing ionic liquid for detection of nitrogen dioxide − a highly toxic gas that is harmful to the environment and presenting a possible threat to human health even at low concentrations. The paper focuses on using noise measurement (electric current fluctuation measurement) for evaluation of electrochemical sensors which were constructed by different fabrication processes: (i) lift-off and drop-casting technology, (ii) screen printing technology on a ceramic substrate and (iii) screen printing on a flexible substrate.
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Abstract

The objective of the study was to compare the impact of three systems of multiannual fertilization applied in two long-term field experiments on the content of phenolic compounds in the soil. In the study, both natural (manure, slurry) and mineral (NPK) fertilizers were used, along with combined, organic-and-mineral fertilization. Experiment I was established in 1972 on grey brown podzolic soil; experiment II, in 1973 on brown soil. In both experiments crops were cultivated in a 7-year rotation, with a 75% share of cereals. The experimental samples were taken from the top layer of soil after 36 (experiment I) and 35 (experiment II) years following the establishment of the experiments. It was demonstrated that the presence of phenolic compounds in the soils was significantly dependent on the contents of organic C and total N, type of soil and the type and dose of used fertilizers. In grey brown podzolic soil, the content of total phenolic compounds was at a lower level than the content found in brown soil. Multiannual fertilization contributed to an increase in the content of total phenolic compounds in relation to the values obtained in control objects, which was particularly reflected in the soil originating from objects fertilized with slurry applied at a dose being equivalent to manure in terms of the amount of introduced organic carbon. The percentage of water-soluble phenols in the total content of these compounds in grey brown podzolic soil was at the level of 18.4%, while in brown soil it amounted to 29.1%.
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Abstract

New York Bay is one of the most important transition regions of ships trading to east America. The region plays an important role in the commerce of the New York metropolitan area. The area is surrounded with the coasts that have various levels of environmental sensitivity. The area accommodates high diversity of native ecosystems and species that are rather vulnerable in case of oil spill. Thus getting well informed about the likelihood, or fate, of oil spills around this region is of great importance so that proactive measures can be taken. The purpose of this study is to investigate the oil spill and predict the future accidents likely to be encountered around the Bay of New York. Two trajectory models have been conducted for the study. ADIOS (Automated Data Inquiry for Oil Spills), has been conducted for natural degradation calculations, and, GNOME (General NOAA Operational Modeling Environment), has been conducted for surface spread simulation. The results gained through these efforts are hoped to be useful for many organizations dealing with oil spill response operations and contribute to an effective and efficient coordination among the relevant institutions.
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Abstract

The sorption isotherm and sorption kinetics of NH4+ by the Fen River reservoir sediment were investigated for a better understanding of the NH4+ sorption characteristics and parameters. The results showed that Q (adsorption content) increased with the increase of Ceq (equilibrium concentration), sorption isotherms could be described by Freundlich equation (R2 from 0.97 to 0.99). Cation exchange capacity (CEC) had a significant correlation with the parameters K and n (R2 was 0.85 and 0.95, respectively). The ENC0 (Ceq as Q was zero) of S1, S2, S3 and S4 was 1.25, 0.57, 1.15 and 1.14 mg L-1, respectively, and they were less than the NH4+ concentrations in reservoir water. The sediments released NH4+ to the Fen River reservoir water and acted as a pollution source, in the form of complex and heterogeneous adsorbents. The NH4+ adsorption kinetic process was composed of ‘fast’ and ‘slow’ reaction patterns and could be fitted using both Elovich equation and Pseudo second-equation. More than one-step may be involved in the NH4+ sorption processes, and interior diffusion was not dominant ion action.
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Abstract

Silver nanoparticles (AgNPs) are widely used in numerous industries and areas of daily life, mainly as antimicrobial agents. The particles size is very important, but still not suffi ciently recognized parameter infl uencing the toxicity of nanosilver. The aim of this study was to investigate the cytotoxic effects of AgNPs with different particle size (~ 10, 40 and 100 nm). The study was conducted on both reproductive and pulmonary cells (CHO-9, 15P-1 and RAW264.7). We tested the effects of AgNPs on cell viability, cell membrane integrity, mitochondrial metabolic activity, lipid peroxidation, total oxidative and antioxidative status of cells and oxidative DNA damage. All kinds of AgNPs showed strong cytotoxic activity at low concentrations (2÷13 μg/ml), and caused an overproduction of reactive oxygen species (ROS) at concentrations lower than cytotoxic ones. The ROS being formed in the cells induced oxidative damage of DNA in alkaline comet assay. The most toxic was AgNPs<10 nm. The results indicate that the silver nanoparticles, especially less than 10 nm, may be harmful to the organisms. Therefore, risk should be considered when using nanosilver preparations and provide appropriate protective measures when they are applied.
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Abstract

22 representative antibiotics, including 8 quinolones (QNs), 9 sulfonamides (SAs), and 5 macrolides (MCs) were selected to investigate their occurrence and removal efficiencies in a Wastewater Treatment Plant (WWTP) and their distribution in the receiving water of the Chaobai River in Beijing, China. Water quality monitoring was performed in an integrated way at different selected points in the WWTP to explore the potential mechanism of antibiotics removal during wastewater treatment. Water quality of the Chaobai River was also analyzed to examine environmental distribution in a river ecosystem. The results showed that within all the 22 compounds examined, 10 antibiotics were quantified in wastewater influent, 10 in effluent, and 7 in river. Sulfadiazine (SDZ, 396 ng/L) and Sulfamethazine (SMZ, 382 ng/L) were the dominating antibiotics in the influent. Both the conventional treatment and advanced Biological Aerated Filter (BAF) system was important for the removal of antibiotics from the wastewater. And the concentrations of selected antibiotics were ranged from 0-41.8 ng/L in the effluent-receiving river. Despite the fact that the concentrations were reduced more than 50% compared to effluent concentrations, WWTP discharge was still regarded as a dominant point-source input of antibiotics into the Chaobai River.
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Abstract

Carbon dioxide sequestration and its long-term immobilisation in biomass is recently an extremely significant problem. Its greatest reserves occur in forests growing all over the globe. A human being, through their conscious action, ought to affect, among other things, the amount of carbon dioxide discharged into the atmosphere and its rational management. Here, quite a good solution seems to be the immobilisation of CO2 in biomass of plants, and in particular, in trees, characterised by their longevity, which are used most frequently for that purpose. Such carbon dioxide management allows for its several-decade immobilisation within living plants, while a further processing of wood mass allows for halting it for consecutive years in products manufactured. Additionally, in the case when within a selected land planted with trees the effluent irrigation is being carried out, simultaneous sewage treatment is also an advantage. By using plants characterised by intense increment in biomass within facilities, also biogens occurring in effluents may be effectively removed. In the analysed case, sewage treatment consisted in entry of household sewage into a prepared surface which was previously subject to mechanical purification. All the sections were sown with grass mixture and plantings of poplar were used. Observations were made during the period of 17 years. The effluents entered onto the surface of the sections and the effluents outflowing from the facility were subject to a physicochemical analysis in order to determine the operational efficiency of a plant - soil treatment system. Also, a threefold inventory of a forest stand was made in order to determine the increment in trees. The last inventory was made in 2014. Based on dendrological characteristics, the average volume of wood mass obtained from the land irrigated with effluents was assessed. A rational management of effluents on the grounds without any central drainage allows for a parallel solution to some problems. First of all, purification of effluents in a natural environment by closing the matter cycle, and additionally contributing to the limitation of carbon dioxide emission by its halting in plant biomass.
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Abstract

The objective of this study was to investigate the possibility of using natural and bacteria-modified Erzurum clayey soil with Methylobacterium extorquens as an alternative to high cost commercial adsorbent materials for the removal of copper from aqueous solution. The copper concentrations in the samples of the polluted river water and CuCl2 solutions treated by the natural and bacteria-modified Erzurum clayey soil (ECS) have been determined by spectrophotometric method. Firstly, the surface of ECS was modified with M. extorquens and surface functionality was increased. Then, the adsorption of Cu (II) from solution phases was studied with respect to varying metal concentration, pH, and temperature and agitation time. The maximum adsorption of Cu (II) for natural and bacteria-modified Erzurum clayey soil was observed at pH: 5.0. At different copper concentrations, copper adsorption analysis was performed on 1 g using clay soil or modified clay soil. Maximum adsorption of Cu (II) was obtained as 45.7 and 48.1 mg g-1 at initial concentration (50 mg/50 mL) and optimal conditions by natural and bacteria-modified clay soil, respectively. The copper concentration was decreased in the substantial amount of the leachates solutions of natural and bacteria-modified clay soil. Langmuir and Freundlich isotherms were used to describe the adsorption behavior of Cu (II) ions. The results showed that modified clay soil had a high level of adsorption capacity for copper ion. The various thermodynamic parameters such as ΔG°, ΔH° and ΔS° were analyzed to observe the nature of adsorption. The structural properties of the natural and bacteria-modified-ECS have been characterized by SEM, FTIR and XRD techniques. Consequently, it was concluded that the bacteria-modified clay soil could be successfully used for the removal of the copper ions from the aqueous solutions.
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