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Angular welding distortion - one sided fillet weld
Dane BadawczeWelding is the basic method of joining ship hull elements during its construction. However, this method of joining structural elements generates shrinks. Shrinks causes deformation of the entire welded structure, both linear and angular. In the shipbuilding industry, there is a tendency to oversize fillet welds, at the design as well as manufacturing...
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Cyclic voltammetry curves for FTO/PANI:WO3 nanocomposite
Dane BadawczeThis dataset contains the results of kinetic electrochemical studies, carried out with cyclic voltammetry (CV) of FTO/PANI:WO3 nanocomposite at various scan rates: 10, 20, 50, 75, 100 and 200 mV/s. The electrolyte was 1M H2SO4 solution. The measurements were performed in a three electrode setup, and with Ag|AgCl|3M KCl as the reference electrode and...
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Projekt systemu sterowania dwukołowym robotem balansującym
PublikacjaW niniejszym artykule rozważony został problem sterowania dwukołowym robotem balansującym. Celem zaprezentowanych prac było zaprojektowanie systemu sterowania tego typu obiektem z wykorzystaniem metod nowoczesnej teorii sterowania. W ramach syntezy, bazując na wyprowadzonym w oparciu o zasady dynamiki Newtona modelu, dobrana została struktura systemu sterowania w postaci regulatora wykorzystującego sprzężenie zwrotne od stanu oraz...
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Flexural buckling and post-buckling of columns made of aluminium alloy
PublikacjaThe paper concerns flexural buckling and initial post-buckling of axially compressed columns made of aluminium alloy described by the Ramberg-Osgood relationship. The non-linear differential equation of the problem is derived using the stationary total energy principle and the assumptions of classical beam theory within a finite range. The approximate analytical solution of the equation leading to the buckling loads and initial...
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Buckling and initial post-local buckling behaviour of cold-formed channel member flange
PublikacjaThe initial post-buckling behaviour of a cold-formed channel member flange after its local buckling is investigated. An axially compressed column or beam subjected to pure bending is considered. The member material is assumed to follow a linear stress-strain relationship. The governing non-linear differential equation of the problem is derived using the minimum total potential energy principle. An approximate solution for the equation...
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A simplified approach to determine the expiration date of certified reference material based on the results of monitoring long-term stability
PublikacjaAll components of the quality assurance (QA) system for measurement results depend heavily on certified reference materials (CRMs). There is a need for a comprehensive discussion of the stability study using the CRM statistical method. Monitoring involves periodic sampling and analysis of the CRM at predetermined intervals to continuously monitor stability without compromising its integrity. The obtained stability data is then...
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Artificial Thermal Ageing of Polyester Reinforced and Polyvinyl Chloride Coated Technical Fabric
PublikacjaArchitectural fabric AF9032 has been subjected to artificial thermal ageing to determine changes of the material parameters of the fabric. The proposed method is based on the accelerated ageing approach proposed by Arrhenius. 300 mm x 50 mm samples were cut in the warp and fill directions and placed in a thermal chamber at 80 °C for up to 12 weeks or at 90 °C for up to 6 weeks. Then after one week of conditioning at ambient temperature,...
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Method of determining the residual fluxes in transformer core
PublikacjaThe article presents the method of calculating the residual induction in transformer columns. The method is based on measurement of the magnetic induction in selected points around the transformer core. The values of residual induction are calculated as linear combination of the results of measurement.
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The hydrogen evolution reaction (HER) performance of some FTO/MoS2/SnO2 electrodes
Dane BadawczeTo demonstrate the electrochemical performance of the FTO/MoS2/SnO2 for HER (hydrogen evolution reaction), the LSV (linear sweep voltammetry) was performed. The polarization curves of the obtained composite were measured in 1 M H2SO4 at room temperature with a scan rate 10 mV/s. For comparison, the LSV for the FTO, pure MoS2 and Pt plate electrode were...
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Impact of Spatial Noise Correlation on Bearing Accuracy in DIFAR Systems
PublikacjaDIFAR type underwater passive systems are one of the more commonly used tools for detecting submarines. At the design stage, which usually uses computer simulations, it is necessary to generate acoustic noise of the sea. It has been shown that correlating noise significantly reduces these errors compared to the assumption that noise is uncorrelated. In addition, bearing errors have been shown to be the same in systems with a commonly...
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Analysis of latency between quotations and capital flow in capital markets.
PublikacjaThe aim of this paper is to prove that the derivative of the log of capital flow understood as price times volume advances the derivative of log of the price. A certain concept of signal processing using linear filtering has been proposed to conduct the research.
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Balance error generated by numerical diffusion in the solution of Muskingum equation
PublikacjaIn the paper the conservative properties of the lumped hydrological models with variable parameters are discussed. It is shown that in the case of the non-linear Muskingum equation the mass balance is not satisfied. The study indicates that the mass balance errors are caused by the improper form of equation and by the numerical diffusion which is generated in the solution. It has been shown that the classical way of derivation...
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Ultrawideband transmission in physical channels: a broadband interference view
PublikacjaThe superposition of multipath components (MPC) of an emitted wave, formed by reflections from limiting surfaces and obstacles in the propagation area, strongly affects communication signals. In the case of modern wideband systems, the effect should be seen as a broadband counterpart of classical interference which is the cause of fading in narrowband systems. This paper shows that in wideband communications, the time- and frequency-domain...
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Modeling variable curvature on the turnout diverging track length
PublikacjaThe paper presents three variants of variable curvature application on the entire length of the turnout diverging track. One linear and two nonlinear curvature cases: described the function of C1 and C0 class were considered. It turned out that both linear curve and the function of C1 class requires a significant (even twice) length of diverging track extending with respect to the base turnout. The curvature described by the function...
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Dynamic Analysis of the Turnout Diverging Track for HSR with Variable Curvature Sections
PublikacjaThe paper presents an analytical method of identifying the curvature of the turnout diverging track consisting of sections of varying curvature. Both linear and nonlinear (polynomial) curvatures of the turnout diverging track are identified and evaluated in the paper. The presented method is a universal one, it enables to assume curvature values at the beginning and end point of the geometrical layout of the turnout. The results...
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Analysis of 2D Feature Spaces for Deep Learning-based Speech Recognition
Publikacjaconvolutional neural network (CNN) which is a class of deep, feed-forward artificial neural network. We decided to analyze audio signal feature maps, namely spectrograms, linear and Mel-scale cepstrograms, and chromagrams. The choice was made upon the fact that CNN performs well in 2D data-oriented processing contexts. Feature maps were employed in the Lithuanian word recognition task. The spectral analysis led to the highest word...
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Gas sensors based on conducting polymers-recent developments
PublikacjaThis work discusses sensing performance dependence of PEDOT polymer and its composites on the counter ions used in the polymerization process. The sensors based on PEDOT-RGO composite show reversible response to NO2, while on PEDOT/LiClO4 irreversible. As a result, PEDOT-RGO could be used as a typical gas sensor, while sensor based PEDOT/LiClO4 could be used as an integrating gas sensor, also known as an accumulating gas sensor....
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Extraction and evaluation of gas-flow-dependent features from dynamic measurements of gas sensors array
PublikacjaGas analyzers based on gas sensors are the devices which enable recognition of various kinds of volatile compounds. They have continuously been developed and investigated for over three decades, however there are still limitations which slow down the implementation of those devices in many applications. For example, the main drawbacks are the lack of selectivity, sensitivity...
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Verification and Benchmarking in MPA Coprocessor Design Process
PublikacjaThis paper presents verification and benchmarking required for the development of a coprocessor digital circuit for integer multiple-precision arithmetic (MPA). Its code is developed, with the use of very high speed integrated circuit hardware description language (VHDL), as an intellectual property core. Therefore, it can be used by a final user within their own computing system based on field-programmable gate arrays (FPGAs)....
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Laser-assisted modification of titanium dioxide nanotubes in a tilted mode as surface modification and patterning strategy
PublikacjaElectrochemical anodization is regarded as a facile and easily scalable fabrication method of titania nanotubes (TiO2NTs). However, due to the extended duration of calcination and further modifications, much faster alternatives are highly required. As a response to growing interest in laser modification of nanotube arrays, a comprehensive investigation of pulsed-laser irradiation and its effect onto TiO2NT properties has been carried out....
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Design and Experimental Validation of a Metamaterial-Based Sensor for Microwave Imaging in Breast, Lung, and Brain Cancer Detection
PublikacjaThis study proposes an innovative geometry of a microstrip sensor for high-resolution microwave imaging (MWI). The main intended application of the sensor is early detection of breast, lung, and brain cancer. The proposed design consists of a microstrip patch antenna fed by a coplanar waveguide with a metamaterial layer-based lens implemented on the back side, and an artificial magnetic conductor (AMC) realized on as a separate...
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Reliable data-driven modeling of high-frequency structures by means of nested kriging with enhanced design of experiments
PublikacjaData-driven (or approximation) surrogate models have been gaining popularity in many areas of engineering and science, including high-frequency electronics. They are attractive as a way of alleviating the difficulties pertinent to high computational cost of evaluating full-wave electromagnetic (EM) simulation models of microwave, antenna, and integrated photonic components and devices. Carrying out design tasks that involve massive...
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High frequency impulse ground penetrating radar application in assessment of interlayer connections
PublikacjaGround Penetrating Radar (GPR) technique is commonly used in the nondestructive evaluation of pavement structures. In particular, this method is used to estimate thicknesses of pavement layers as well as it can be utilized in advanced studies of pavement structures. The device presented in this paper comprise the high frequency impulse antennas that allow for investigating the interlayer zones in terms of their electromagnetic...
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Bridge Non-Destructive Measurements Using a Laser Scanning during Acceptance Testing: Case Study
PublikacjaOwing to the recent proliferation of inventory works on roads and railways, bridge acceptance tests have increased exponentially. These tests’ results are often misinterpreted owing to the use of various measuring equipment types, rendering integrated interpretation problematic. It is also problematic that adjusting the measurement method is difficult when the structure’s response to load is uncertain. Therefore, it is important...
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Waves in a short cable at low frequencies, or just hand-waving? What does physics say? (Invited paper)
PublikacjaWe address the question of low-frequency signals in a short cable, which are often considered as waves in engineering calculations. Such an assumption violates several laws of physics, but exact calculations can be carried out via linear network theory.
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Could thermal imaging supplement surface electromyography measurements for skeletal muscles?
PublikacjaAbstract—(1) Background: The aim of this study is to present the results of experiments in which surface electromyography (sEMG) and thermal imaging were used to assess muscle activation during gait and to verify the hypothesis that there is a relationship in the case of low fatigue level between sEMG measured muscle activation, assessed in the frequency domain, and thermal factors calculated as minimum, maximum, kurtosis, mean,...
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Dynamic Bayesian Networks for Symbolic Polyphonic Pitch Modeling
PublikacjaSymbolic pitch modeling is a way of incorporating knowledge about relations between pitches into the process of an- alyzing musical information or signals. In this paper, we propose a family of probabilistic symbolic polyphonic pitch models, which account for both the “horizontal” and the “vertical” pitch struc- ture. These models are formulated as linear or log-linear interpo- lations of up to fi ve sub-models, each of which is...
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Local buckling of thin-walled channel member flange made of aluminum alloy
PublikacjaThe paper deals with local stability of the thin-walled compressed flange of channel columns and beams made of aluminum alloy. The aim of paper is to find critical stress of local buckling of the flange member taking into account the web-flange interaction in linear and nonlinear elastic range of the member material. The governing differential equation of the problem is derived with aid of the principle of stationary total potential...
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Rapid Yield Estimation and Optimization of Microwave Structures Exploiting Feature-Based Statistical Analysis
PublikacjaIn this paper, we propose a simple, yet reliable methodology to expediteyield estimation and optimization of microwave structures. In our approach,the analysis of the entire response of the structure at hand (e.g., $S$-parameters asa function of frequency) is replaced by response surface modeling of suitablyselected feature points. On the one hand, this is sufficient to determinewhether a design satisfies given performance specifications....
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Sensor Position Estimation Method for IoT Using Mobile Reference Node
PublikacjaThe paper proposes an innovative method of locating objects for the Internet of Things (IoT). The proposed method allows the position of a fixed measuring sensor (MS) to be estimated using one mobile base station with a known position moving around the MS. The mathematical analysis of the method, and three algorithms — Newton’s (NA), gradient descent (GD) and genetic (GA) — for solving the system of non-linear positional equations...
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Measurements of Dispersed Phase Velocity in Two-Phase Flows in Pipelines Using Gamma-Absorption Technique and Phase of the Cross-Spectral Density Function
PublikacjaThis paper concerns the application of the gamma radiation absorption method in the measurements of dispersed phase velocity in two-phase flows: liquid–gas flow in a horizontal pipe- line and liquid–solid particles in a vertical pipe. Radiometric sets containing two linear 241Am gamma radiation sources and two NaI(Tl) scintillation detectors were used in the research. Due to the stochastic nature of the signals obtained from the...
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Analogues of trypsin inhibitor SFTI-1 modified in the conserved P1′ position by synthetic or non-proteinogenic amino acids retain their inhibitory activity
PublikacjaA series of linear and monocyclic (with a disulfide bridge only) analogues of trypsin inhibitor SFTI-1 modified in the P-1 and/or P-1' positions were synthesized by the solid-phase method. In the substrate specificity P-1 position, Phe or N-benzylglycine (Nphe) were introduced, whereas the conserved Ser6 in Bownam-Birk (BBI) inhibitors was replaced by Hse (L-homoserine), Nhse [N-(2-hydroxyethyl)glycine], Sar, and Ala. Kinetic studies...
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On forced vibrations of piezo-flexomagnetic nano-actuator beams
PublikacjaThe effect of excitation frequency on the piezomagnetic Euler-Bernoulli nanobeam taking the flexomagnetic material phenomenon into consideration is investigated in this chapter. The magnetization with strain gradients creates flexomagneticity. We couple simultaneously the piezomagnetic and flexomagnetic properties in an inverse magnetization. Resemble the flexoelectricity, the flexomagneticity is also size-dependent. So, it has...
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An optimal form of the finite element mass matrix in the analysis of longitudinal vibrations of rods
PublikacjaIn this paper, an attempt is made to find the optimal form of the mass matrix of a rod finite element, which allows one to obtain the smallest errors in the longitudinal frequency determination of natural vibrations of any boundary conditions within the whole range of determined frequencies. It is assumed that the mass matrix can be treated as a linear combination of the consistent and diagonal matrices. Based on analytical considerations,...
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An analysis of observability and detectability for different sets of measured outputs - CSTR case study
PublikacjaA problem of proving the observability/detectability at a given measured output for non-linear biochemical systems has been addressed in this paper. A theory of indistinguishable state trajectories has been used to prove the properties of the observability or detectability of this system. It is related to taking system dynamics into consideration depending on initial conditions and the impact of inputs taking into account a given...
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Impact of Geometrical Imperfections on Estimation of Buckling and Limit Loads in a Silo Segment Using the Vibration Correlation Technique
PublikacjaThe paper examines effectiveness of the vibration correlation technique which allows determining the buckling or limit loads by means of measured natural frequencies of structures. A steel silo segment with a corrugated wall, stiffened with cold-formed channel section columns was analysed. The investigations included numerical analyses of: linear buckling, dynamic eigenvalue and geometrically static non-linear problems. Both perfect...
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Superconductivity in the superhard boride WB4.2
PublikacjaWe show that the superhard boride WB4.2 is a superconductor with a Tc of 2.05(5) K. Temperature-dependent magnetic susceptibility, electrical resistivity, and specific heat measurements were used to characterize the superconducting transition. The Sommerfeld constant γ for WB4.2 is 2.07(3) mJ mol−1 K−2 and the ΔC/γTc=1.56, which is somewhat higher than what is expected for weakly coupled Bardeen–Cooper–Schrieffer type superconductors....
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Buckling of simplified models of silo with corrugated walls and vertical stiffeners
PublikacjaThe paper deals with buckling of cylindrical silos composed of corrugated sheets and vertical stiffeners (columns). Comprehensive finite element analyses were carried out for a perfect silo by means of a linear buckling approach. Corrugated walls were simulated as an equivalent orthotropic shell and vertical thin-walled columns as beam elements. Calculations for perfect silos with different numbers of columns made it possible to...
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An Improvement of Global Complex Roots and Poles Finding Algorithm for Propagation and Radiation Problems
PublikacjaAn improvement of the recently developed global roots finding algorithm has been proposed. The modification allows to shorten the computational time by reducing the number of function calls. Moreover, both versions of the algorithms (standard and modified) have been tested for numerically defined functions obtained from spectral domain approach and field matching method. The tests have been performed for three simple microwave...
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Pin-on-Substrate Gap Waveguide: An Extremely Low-Cost Realization of High-Performance Gap Waveguide Components
PublikacjaConsidering the limitations of currently available technologies for the realization of microwave components and antennas, a trade-off between different factors including the efficiency and fabrication cost is required. The main objective of this letter is to propose a novel method for the realization of gap waveguides (GWGs) that take advantage of conventional PCB fabrication technology, thus are low cost and light weight. Moreover,...
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Fractional differential equations with causal operators
PublikacjaWe study fractional differential equations with causal operators. The existence of solutions is obtained by applying the successive approximate method. Some applications are discussed including also the case when causal operator Q is a linear operator. Examples illustrate some results.
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The Complexity of Zero-Visibility Cops and Robber
PublikacjaIn this work we deal with the computational complexity aspects of the zero-visibility Cops and Robber game. We provide an algorithm that computes the zero-visibility copnumber of a tree in linear time and show that the corresponding decision problem is NP-complete even for the class of starlike graphs.
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Resource productivity and environmental degradation in EU-27 countries: context of material footprint
PublikacjaThis study explores the relationship between the resource productivity and environmental degradation in European Union-27 countries. This study tests this relationship in context of high, moderate, and low material footprint sub-samples; these samples are formed utilizing the expectation–maximization machine learning algorithm. Using the panel data set of EU-27 countries from 2000 to 2020, linear and non-linear autoregressive distributed...
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Highly selective impedimetric determination of Haemophilus influenzae protein D using maze-like boron-doped carbon nanowall electrodes
PublikacjaThis study reports a novel impedimetric immunosensor for protein D detection in purified and bacterial (Haemophilus influenzae, Hi) samples. The detection was based on antigen recognition by anti-protein D antibodies (apD) immobilised at the maze-like boron-doped carbon nanowall electrodes (B:CNW). The B:CNW electrodes were synthesised, and their surface was characterised by scanning electron microscopy (SEM) and X-ray photoelectron...
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Assessment of the Impact of GNSS Processing Strategies on the Long-Term Parameters of 20 Years IWV Time Series
PublikacjaAdvanced processing of collected global navigation satellite systems (GNSS) observations allows for the estimation of zenith tropospheric delay (ZTD), which in turn can be converted to the integrated water vapour (IWV). The proper estimation of GNSS IWV can be affected by the adopted GNSS processing strategy. To verify which of its elements cause deterioration and which improve the estimated GNSS IWV, we conducted eight reprocessings...
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Job-related emotions and job burnout among civil servants: examining the shape of the relationship in cross-sectional and longitudinal models
PublikacjaWstęp: Związek pozytywności, czyli proporcji między pozytywnymi a negatywnymi emocjami, z wypaleniem zawodowym może przybierać kształt krzywoliniowy. Ponadto z perspektywy teoretycznej jest to relacja przyczynowo - skutkowa, w której pozytywność jest proksymalnym, a wypalenie – dystalnym wymiarem dobrostanu zawodowego. Dotychczasowe badania były jednak prowadzone najczęściej w planie poprzecznym i testowały relacje prostoliniowe....
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Ali Farahbakhsh dr
Osoby -
Numerical Methods for Partial Differential Equations
Kursy OnlineCourse description: This course focuses on modern numerical techniques for linear and nonlinear elliptic, parabolic and hyperbolic partial differential equations (PDEs), and integral equations fundamental to a large variety of applications in science and engineering. Topics include: formulations of problems in terms of initial and boundary value problems; finite difference and finite element discretizations; boundary element approach;...
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On unique kinematics for the branching shells
PublikacjaWe construct the unique two-dimensional (2D) kinematics which is work-conjugate to the exact, resultant local equilibrium conditions of the non-linear theory of branching shells. Several types of junctions are described. For each type the explicit form of the principle of virtual work is derived.
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The effect of anionic surfactant concentration on activated sludge condition and phosphate release in biological treatment plant
PublikacjaThis paper discusses the influence of a wide range of anionic surfactant concentrations on activated sludge. Linear alkylbenzene sulphonate (LAS) was chosen as an example of a commonly used anionic surfactant. The fate of the surfactant during biological treatment of wastewater was tested. The effect of surfactant on glucose and starch removal was studied.