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Search results for: THEORETICAL INVESTIGATIONS
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Case Study of Stray Current Corrosion of Tall Ship Mast
PublicationNowadays, in the present technical civilization there are numerous complex technical systems that may generate various hazards. Large transport units like ships can be considered as the most dangerous systems. Therefore, it is important to eliminate all possible hazards, especially for ship crewmembers. Destruction of ship structural components caused by vast corrosion is one of these hazards. Usually, its activity leads to a decrease...
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Application of H2O2 to optimize ammonium removal from domestic wastewater
PublicationThe paper presents the results of application of hydrogen peroxide (H2O2) for the optimization of the effects of ammonia nitrogen removal from domestic wastewater. The investigations were carried out at a model wastewater treatment plant consisting of a preliminary sedimentation tank and a sand filter with a horizontal flow of wastewater at a constant hydraulic load of 1.44 L/day. The efficiency of ammonia nitrogen removal was...
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Non-destructive inspection of ground anchors using guided wave propagation
PublicationThis paper deals with numerical and experimental investigations of specific problems of guided wave propagation in ground anchors. The research focuses on recognizing the phenomenon of the energy transfer between anchor components. Particular attention is paid to characteristic features of guided waves propagating in free and embedded parts of the tendon, at the interface between the tendon and the surrounding anchor body as well...
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Photoelectron spectroscopy of a series of acetate and propionate esters
PublicationThe electronic state and photoionization spectroscopy of a series of acetate esters: methyl acetate, isopropyl acetate, butyl acetate and pentyl acetate as well as two propionates: methyl propionate and ethyl propionate, have been determined using vacuum-ultraviolet photoelectron spectroscopy. These experimental investigations are complemented by ab initio calculations. The measured first adiabatic and vertical ionization energies...
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Comparison of low-temperature cracks intensity on pavements with high modulus asphalt concrete and conventional asphalt concrete bases
PublicationHigh modulus asphalt concrete (HMAC) base courses provide very good resistance to rutting and fatigue but they can increase the risk of low-temperature cracking as compared with conventional asphalt concrete (AC). The article presents the comparison of these two road materials in terms of low-temperature cracking. The statistical method based on the ordered logistic regression model was used. The analysis was based on results of...
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ENVIRONMENTAL DEGRADATION OF DISSIMILAR AUSTENITIC 316L AND DUPLEX 2205 STAINLESS STEELS WELDED JOINTS
PublicationThe paper describes structure and properties of dissimilar stainless steels welded joints between duplex 2205 and austenitic 316L steels. Investigations were focused on environmentally assisted cracking of welded joints. The susceptibility to stress corrosion cracking (SCC) and hydrogen embrittlement was determined in slow strain rate tests (SSRT) with the strain rate of 2.2 × 10–6 s–1. Chloride-inducted SCC was determined in the...
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Polish experience with cold in-place recycling
PublicationDeep cold in-place recycling using cement and asphalt emulsion has been used for reconstruction of existing roads since the beginning of the 1990s. This paper describes the first Polish requirements for mineral-cement-emulsion mixtures. As requirements stated for the strength of the mineral-cement-emulsion mixtures were quite high, most of the mixtures were designed using high amount of cement and aggregate added for the improvement...
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Miniaturized passive emission test chamber for in-situ measurement of emissions of organic compounds
PublicationThe results of many different studies have demonstrated unequivocally that the quality of indoor air is often much worse than that of atmospheric air (outdoor). One of the main groups of chemical compounds present in indoor air, with proven harmfulness to health,are volatile organic compounds (VOCs). VOCs present indoor comprise a wide variety of hydrocarbons and hydrocarbons derivatives including aliphatic, aromatics, alkylbenzens,...
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Hydrogen production from ethanol In nitrogen microwave plasma At atmospheric pressure
PublicationHydrogen seems to be one of the most promising alternative energy sources. It is a renewable fuel as it could be produced from e.g. waste or bio-ethanol. Furthermore hydrogen is compatible with fuel cells and is environmentally clean. In contrast to conventional methods of hydrogen production such as water electrolysis or coal gasification we propose a method based on atmospheric pressure microwave plasma. In this paper we present...
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Modelling of some stealth features for a small navy ship at the concept design stage.
PublicationIn this paper the basic research problems associated with modelling the basic stealth features for a small navy ship at the concept design stage are introduced. Amongst the major stealth features considered are: the modification of the immersed ship hull form by a rapid change of the ship loading condition, and modification of the ship boundary layer by the hull skin cover. The other stealth features of the ship are not presented...
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Diagnostics of induction motor bearings - possibility of measurements
PublicationIn induction motors damage in the elements of electromagnetic system, for example in the wiring of stator, rotor or in the magnetic circuit can appear as well as damage of mechanical parts (bearings, rotor, shaft). Bearing diagnostics is so important in supervision of motor condition, because extensive research shows that the bearings arethe elements most susceptible to damage. This paper presents the research which the author...
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Towards a reliable method for extrapolation of propulsion performance for vessels with twin-crp-pod system
PublicationThe study presents power performance prediction of an Ultra Large Container Ship (ULCS) with hybrid twin-crp-pod propulsion system. Twin crp-pod propulsion system is a combination of three concepts: twin screw, contra-rotating propellers (crp) and conventional shaft propellers with pod propulsors behind. The presented study shows the current extrapolation method for crp propulsion systems and tries to point out its weaknesses....
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Thermal Instability of Gold Thin Films
PublicationThe disintegration of a continuous metallic thin film leads to the formation of isolated islands, which can be used for the preparation of plasmonic structures. The transformation mechanism is driven by a thermally accelerated diffusion that leads to the minimalization of surface free energy in the system. In this paper, we report the results of our study on the disintegration of gold thin film and the formation of nanoislands...
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Removal of cyclohexane vapors from air in biotrickling filters: Effects of gas mixture composition and circular economy approach
PublicationThis work presents results of investigations on biotrickling filtration of air polluted with cyclohexane co-treated in binary, ternary and quaternary volatile organic compounds (VOCs) mixtures, including vapors of hexane, toluene and ethanol. The removal of cyclohexane from a gas mixture depends on the physicochemical properties of the co-treated VOCs and the lower the hydrophobicity of the VOC, the higher the removal efficiency...
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Heat recovery from the hybrid photovoltaic tile – experimental studies with the solar light simulator
PublicationConsidering the current development of micro-cogeneration energy sources, supported by the national prosumer policy and the act on the renewable energy sources, there is a great demand for the effective solar technologies. In this area, the photovoltaic cells with a combined conversion of the solar radiation energy into the electrical and thermal energy (PV/T cells) seem to be attractive. They are already widely available and treated...
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Determination of Thermophysical Parameters Involved in The Numerical Model to Predict the Temperature Field of Cast-In-Place Concrete Bridge Deck
PublicationThe paper dealswith a concept of a practical computationmethod to simulate the temperature distribution in an extradosed bridge deck. The main goal of the study is to develop a feasible model of hardening of concrete consistent with in-situ measurement capabilities. The presented investigations include laboratory tests of high performance concrete, measurements of temperature evolution in the bridge deck and above all, numerical...
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Thermal-Hydraulic Studies on the Shell-and-Tube Heat Exchanger with Minijets
PublicationIn this paper a patented design of a heat exchanger with minijets, with a cylindrical construction is presented. It is followed by the results of its systematic experimental investigations in the single-phase convection heat transfer mode. Based on these results, validation of selected correlations (coming from the literature) describing the Nusselt number was carried out. An assessment of the heat exchange intensification level...
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PRESSURE DROP OF HFE7000 AND HFE7100 IN FLOW CONDENSATION IN MINICHANNELS WITH ACCOUNT OF NON-ADIABATIC EFFECTS
PublicationFlow boiling and flow condensation are often regarded as two opposite or symmetrical phenomena involving the change of phase. There is a temptation to describe both these phenomena with one only correlation. From amongst the structures present in flow boiling and flow condensation at least the annular flow structure seems to be mostly appropriate to the common modeling. However, the shear stress acting between vapor phase and liquid...
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IMPACT-TOUGHNESS INVESTIGATIONS OF DUPLEX STAINLESS STEELS
PublicationDuplex stainless steels are very attractive constructional materials for use in aggressive environments because of their several advantages over austenitic stainless steels. Duplex steels have excellent pitting and crevice corrosion resistance, are highly resistant to chloride stress-corrosion cracking and are about twice as strong as common austenitic steels. Better properties are associated with their microstructures consisting...
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Experimental and Computational Fluid Dynamics Studies on Straight and U-Bend Double Tube Heat Exchangers with Active and Passive Enhancement Methods
PublicationIn this work, the authors wanted to demonstrate the possibility to increase the heat transfer efficiency by using simple wire coil inserts to create turbulent flow in the boundary layer as well as air blowing into the annulus of the pipe. Experimental investigations were carried out for four heat exchanger constructions, i.e., plain double tube, turbulized double tube, plain U-bend double tube, U-tube with turbulator, plain double...
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Shear fracture of longitudinally reinforced concrete beams under bending using Digital Image Correlation and FE simulations with concrete micro-structure based on X-ray micro-computed tomography images
PublicationThe paper presents experimental and numerical investigations of the shear fracture in rectangular concrete beams longitudinally reinforced with steel or basalt bar under quasi-static three point bending. Shear fracture process zone formation and development on the surface of beams was investigated by Digital Image Correlation (DIC) whereas thorough analyses of 3D material micro-structure, air voids, width and curvature of shear...
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Enhancement of the Magnetic Coupling in Exfoliated CrCl 3 Crystals Observed by Low‐Temperature Magnetic Force Microscopy and X‐ray Magnetic Circular Dichroism
PublicationMagnetic crystals formed by 2D layers interacting by weak van der Waals forces are currently a hot research topic. When these crystals are thinned to nanometric size, they can manifest strikingly different magnetic behavior compared to the bulk form. This can be the result of, for example, quantum electronic confinement effects, the presence of defects, or pinning of the crystallographic structure in metastable phases induced by...
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Mechanical, Thermal and Rheological Properties of Polyethylene-Based Composites Filled with Micrometric Aluminum Powder
PublicationInvestigations related to polymer/metal composites are often limited to the analysis of the electrical and thermal conductivity of the materials. The presented study aims to analyze the impact of aluminum (Al) filler content (from 1 to 20 wt%) on the rarely investigated properties of composites based on the high-density polyethylene (HDPE) matrix. The crystalline structure, rheological (melt flow index and oscillatory rheometry),...
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New potent steroid sulphatase inhibitors based on 6-(1-phenyl-1H-1,2,3-triazol-4-yl)naphthalen-2-yl sulphamate derivatives
PublicationIn the present work, we report a new class of potent steroid sulphatase (STS) inhibitors based on 6-(1-phenyl-1H-1,2,3-triazol-4-yl)naphthalen-2-yl sulphamate derivatives. Within the set of new STS inhibitors, 6-(1-(1,2,3-trifluorophenyl)-1H-1,2,3-triazol-4-yl)naphthalen-2-yl sulphamate 3L demonstrated the highest activity in the enzymatic assay inhibiting the STS activity to 7.98% at 0.5 µM concentration. Furthermore, to verify...
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Removal of cyclohexane and ethanol from air in biotrickling filters inoculated with Candida albicans and Candida subhashii
PublicationThis paper presents investigations on the removal of cyclohexane and ethanol from air in polyurethane- -packed biotrickling filters, inoculated with Candida albicans and Candida subhashii fungal species. Results on process performance together with flow cytometry analyses of the biofilm formed over packing elements are presented and discussed. The results indicate that the presence of ethanol enhances the removal efficiency of cyclohexane...
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Performance Evaluation of a Multidomain IMS/NGN Network Including Service and Transport Stratum
PublicationThe Next Generation Network (NGN) architecture was proposed for delivering various multimedia services with guaranteed quality. For this reason, the elements of the IP Multimedia Subsystem (IMS) concept (an important part of 4G/5G/6G mobile networks) are used in its service stratum. This paper presents comprehensive research on how the parameters of an IMS/NGN network and traffic sources influence mean Call Set-up Delay (E(CSD))...
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Impact of low-temperature sintering on the Fe-based amorphous coatings
PublicationBulk metallic glasses (BMGs) have gained a lot of attention in recent years due to their outstanding properties such as high hardness and excellent wear and corrosion resistance. However, they are restricted in industrial applications due to their extreme brittleness. Iron based amorphous coatings from BMGs are the best solution to use them by overcoming the problem of extreme brittleness. The coatings can be sprayed by various...
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Comprehensive Review of Fluorescence Applications in Gynecology
PublicationSince the introduction of indocyanine green (ICG) as a fluorophore in near-infrared imaging, fluorescence visualization has become an essential tool in many fields of surgery. In the field of gynecology, recent new applications have been proposed and found their place in clinical practice. Different applications in gynecology were investigated, subcategorized, and overviewed concerning surgical applications and available dyes....
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Variations in host surfaces morphology and biology of ciliate epibionts explaining distribution pattern of epibionts in the invasive signal crayfish Pacifastacus leniusculus (Dana, 1852)
Publicationciliates on the signal crayfish Pacifastacus leniusculus in relation to specialized structures of the host’s exoskeleton for the first time. This species is known to maintain a relatively clean carapace, but it is sometimes overgrown by other organisms. Epibionts cover different parts of the signal crayfish body, mainly antennae, antennules, maxillipedes III and pereiopods with inner edges of chelae; however, some parts of the...
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Growth inhibition of cultured cancer cells by Ribes nigrum leaf extract
PublicationThe present article includes data on the possible selective cytotoxic effect of extract of Ribes nigrum L. growing at high Armenian landscape. For this purpose, different non-cancer (microglial BV-2 wild type (Wt), acyl-CoA oxidase 1 (ACOX1) deficient (Acox1-/-) and cancer (human colon adenocarcinoma HT29 and human breast cancer MCF7) cell lines were applied. R. nigrum leaf ethanol extract showed a growth inhibition effect towards...
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The Way One Defines Specification Matters: On the Performance Criteria for Efficient Antenna Optimization in Aggregated Bi-Objective Setups
PublicationDesign of antenna structures for real-world applications is a challenging task that often involves addressing multiple design requirements at a time. Popular solution approaches to this class of problems include utilization of composite objectives. Although configuration of such functions has a significant effect on the cost and performance of the optimization, their specific structure is normally determined based on engineering...
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Human subarachnoid space width oscillations in the resting state
PublicationAbnormal cerebrospinal fluid (CSF) pulsatility has been implicated in patients suffering from various diseases, including multiple sclerosis and hypertension. CSF pulsatility results in subarachnoid space (SAS) width changes, which can be measured with near-infrared transillumination backscattering sounding (NIR-T/BSS). The aim of this study was to combine NIR-T/BSS and wavelet analysis methods to characterise the dynamics of the...
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Numerical analyses of novel prefabricated structural wall panels in residential buildings based on laboratory tests in scale 1:1
PublicationThe paper presents experimental and numerical investigations on novel prefabricated composite building wall panels for residential building constructions. The wall panels were composed of reinforced concrete ribbed elements with the core from the EPS foam as the thermal insulation. The wall panels in the full-scale 1:1 were subjected to vertical loads. In the first step, the experiments were analysed with simple usual static methods....
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Assessment of FSW Welds Made of Aluminum Alloy AW7075-T651.
PublicationThis paper summarizes the results of experimental studies in which the aluminum alloy AW7075-T651 was friction stir welded (FSW) using various combinations of process parameters (rotational - R and travel speed - T). Mechanical properties of the test welds were assessed by using static tensile test and Vickers hardness measurement. The temperature of the welded plates was monitored during welding by means of thermocouples placed...
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Nitrogen fraction fluctuation during wastewater treatment in a multistage treatment wetland
PublicationAlthough the size of pollutants discharged to a WWTP plays an important and often underestimated role in characterizing treat ability and hence the degree of contaminant removal of wastewater. From one hend In order to obtain efficient nitrogen removal in thedenitrification process, sufficient amounts of bioavailable carbon source should be ensured bur for the other hand in TWs, particulates from the wastewater are naturally trapped...
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Operational problems of large power diesel engines combusting biofuels, considered togetherwith assessment of their operation
PublicationWithin this article the issue of large power self ignition engines fed with biofuels has been undertaken. The analysis focused mainly on operation problems. There has been noticed some advantages and difficulties associated with the biofuel application to self ignition engines. The research problem has been characterised and the research purposes have been proposed enabling the most profitable formation of energetic features of...
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Effective method of treatment of effluents from production of bitumens under basic pH conditions using hydrodynamic cavitation aided by external oxidants
PublicationUtilization of cavitation in advanced oxidation processes (AOPs) is a promising trend in research on treatment of industrial effluents. The paper presents the results of investigations on the use of hydrodynamic cavitation aided by additional oxidation processes (O3/H2O2/Peroxone) to reduce the total pollution load in the effluent from the production of bitumens. A detailed analysis of changes in content of volatile organic compounds...
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Explanation of Reduction of Pressure Forces in Turbine Chamber Seals
PublicationThe paper describes a chamber seal reducing the aerodynamic forces created in shroud seals. Asymmetrical pressure distribution (due to rotor-stator eccentricity) in the blade tip clearance leads to the creation of pressure forces acting on the blade shroud. By increasing the volume above the shroud, the pressure distribution becomes more uniform on the whole shroud circumference and the effect of rotor eccentricity is reduced....
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The impact of precipitation and external carbon source addition on biological nutrient removal in activated sludge systems - experimentalinvestigation and mathematical modeling
PublicationThe aim of this study was to determine the effects of chemical precipitation and addition of external carbonsources on the denitrification capability and enhanced biological phosphorus removal (EBPR) interactions atthe 'Wschod' WWTP (600,000 PE) in Gdansk (northern Poland). For this purpose, different kinds of batch experimentswere carried out with the settled wastewater (without pretreatment and after coagulation-flocculation)and...
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Explanation of Reduction of Pressure Forces in Turbine Chamber Seals
PublicationThe paper describes a chamber seal reducing the aerodynamic forces created in shroud seals. Asymmetrical pressure distribution (due to rotor-stator eccentricity) in the blade tip clearance leads to the creation of pressure forces acting on the blade shroud. By increasing the volume above the shroud, the pressure distribution becomes more uniform on the whole shroud circumference and the effect of rotor eccentricity is reduced....
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Changes of microbiological quality of water in distribution system. Zmiany mikrobiologicznej jakości wody w sieci dystrybucyjnej.
PublicationW artykule przedstawiono mikrobiologiczną jakość wody podziemnej uzdatnianej w dwóch stacjach oczyszczania wody (WTP I i WTP II), w sieci dystrybucyjnej. Obie stacje uzdatniania stosują dezynfekcję za pomocą dwutlenku chloru. Badania wykazały wzrost ogólnej liczby bakterii w miarę zwiększania się odległości od stacji uzdatniania.In the paper microbiological quality of water in distribution system produced in two ground water treatment...
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Compliance tests of the polymer layers used as hydrodynamic bearing coatings
PublicationOperational experience and scientific investigations results showed that polymer lined hydrodynamic bearings can withstand more severe operating conditions compared than white metal bearings. PTFE and PEEK-based coatings are the most frequently used as Babbitt alternatives. Both polymers differ significantly from the each other in material properties. According to catalogue data compression modulus of PTFE, it is about an order...
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Anion–water interactions of weakly hydrated anions: molecular dynamics simulations of aqueous NaBF4 and NaPF6
PublicationIn aqueous ionic solutions, both the structure and the dynamics of water are altered dramatically with respect to the pure solvent. The emergence of novel experimental techniques makes these changes accessible to detailed investigations. At the same time, computational studies deliver unique possibilities for the interpretation of the experimental data at the molecular level. Here, using molecular dynamics simulations, we demonstrate...
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Waste printer ink as modifier for natural rubber/carbon black composites: No haste, use waste
PublicationFrom a sustainability perspective, achieving a greener future with a minimal carbon footprint requires maximizing waste materials' reuse. The four pillars of satisfying customer demands are processing, price, properties, and performance. Along with such a global policy, this work seeks to utilize waste printer ink (WPI) as a source of carbon in combination with low- and high-surface carbon black (LCB and HCB, respectively) additives...
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Processing, Mechanical and Morphological Properties of GTR Modified by SBS Copolymers
PublicationIn this work, ground tire rubber (GTR) was thermo-mechanically treated in the presence of styrene-butadiene-styrene (SBS) copolymers. During preliminary investigation, the effects of different SBS copolymer grades, the variable content of SBS copolymer on the Mooney viscosity, and the thermal and mechanical properties of modified GTR were determined. Subsequently, GTR modified by SBS copolymer and cross-linking agents (sulfur-based...
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The impact of precipitation and external carbon source addition on biological nutrient removal in activated sludge systems – experimental investigation and mathematical modeling
PublicationThe aim of this study was to determine the effects of chemical precipitation and addition of external carbonsources on the denitrification capability and enhanced biological phosphorus removal (EBPR) interactions atthe ‘Wschod’ WWTP (600,000 PE) in Gdansk (northern Poland). For this purpose, different kinds of batch experimentswere carried out with the settled wastewater (without pretreatment and after coagulation-flocculation)and...
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Synthesis and hydrogen evolving catalysis of a panchromatic photochemical molecular device
PublicationA dinuclear hydrogen evolution photocatalyst [(tbbpy)2Os(tpphz)PtI2](PF6)2 (tbbpy = 4,4′-tert-butyl-2,2′-bipyridine; tpphz = tetrapyrido[3,2-a:2′,3′-c:2′′,3′′-h:2′′′,3′′′-j]phenazine) is synthesized in order to make use of the broader range of visible light absorption mitigated by the osmium center. In a first step, the activity of the complex for hydrogen evolution is investigated by evaluating the role of different electron donors...
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AC motor feeding cable consequences on EMC performance of ASD
PublicationHigh level of conducted EMI emissions of adjustable speed drives (ASD) is one of the most difficult problems in contemporary applications. Many investigations are carried out in order to find more effective methods allowing to predict this emission at early stage of design, and therefore to predict adequate countermeasures. This paper deals with the method which allows to estimate by simulation the influence of motor feeding cable...
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Instrumental measurement of odour nuisance in city agglomeration using electronic nose
PublicationThe paper describes an operation principle of odour nuisance monitoring network in a city agglomeration. Moreover, it presents the results of investigation on ambient air quality with respect to odour obtained during six-month period. The investigation was carried out using a network comprised of six prototypes of electronic nose and Nasal Ranger field olfactometers employed as a reference method. The monitoring network consisted...
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A mathematical model of rheological behavior of novel bio-based isocyanate-terminated polyurethane prepolymers
PublicationIn this paper, the results of rheological study on isocyanate-terminated polyurethane prepolymers, containing modified soybean oil residues incorporated into the chemical structure are described. Isocyanate-terminated prepolymers were synthesized from 4,4′-diphenylmethane diisocyanate and the mixture of hydroxylated soybean oil and commercial polyether. The measurements were performed by using rotary rheometer R/S-CPS+ (Brookfield,...