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Wyniki wyszukiwania dla: FINITE VOLUME METHOD
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A new concept of PWM duty cycle computation using the Barycentric Coordinates in a Three-Dimensional voltage vectors arrangement
PublikacjaThe paper presents a novel approach to the Pulse Width Modulation (PWM) duty cycle computing for complex or irregular voltage vector arrangements in the two (2D) and three–dimensional (3D) Cartesian coordinate systems. The given vectors arrangement can be built using at least three vectors or collections with variable number of involved vectors (i.e. virtual vectors). Graphically, these vectors form a convex figure, in particular,...
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Rapid tolerance‐aware design of miniaturized microwave passives by means of confined‐domain surrogates
PublikacjaThe effects of uncertainties, primarily manufacturing tolerances but also incomplete information about operating conditions or material parameters, can be detrimental to the performance of microwave components. Quantification of such effects is essential to ensure a meaningful evaluation of the structure, in particular, its reliability under imperfect fabrication procedures. The improvement of the circuit robustness can be achieved...
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Effects of consecutive apneas on pial artery pulsation and subarachnoid width in healthy subjects
PublikacjaHypercapnia is known to dilate the pial artery, disrupt cerebral autoregulation and increase pial artery pulsation. The cerebral blood flow velocity (CBFV) response to hypercapnia is biphasic. Below the threshold for the increase of blood pressure (BP) with carbon dioxide partial pressure (pCO2), the CBFV measurement reflects vascular reactivity to pCO2 alone at a constant BP. Above this threshold, the CBFV measurement provides...
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Big Data i 5V – nowe wyzwania w świecie danych (Big Data and 5V – New Challenges in the World of Data)
PublikacjaRodzaje danych, składające się na zbiory typu Big Data, to m.in. dane generowane przez użytkowników portali internetowych, dane opisujące transakcje dokonywane poprzez Internet, dane naukowe (biologiczne, astronomiczne, pomiary fizyczne itp.), dane generowane przez roboty w wyniku automatycznego przeszukiwania przez nie Internetu (Web mining, Web crawling), dane grafowe obrazujące powiązania pomiędzy stronami WWW itd. Zazwyczaj,...
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Comparison of volume-and surface-detention-time distributions
PublikacjaCzas zatrzymania ścieków w reaktorze jest bardzo ważnym parametrem projektowym. Jego wyznaczenie jest trudne i kłopotliwe. Z tego względu zbadano możliwość zastąpienia wartości tego parametru, wyznaczonej tylko dla swobodnej powierzchni ścieków. W wyniku stwierdzono dopuszczalność takiej zamiany.
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On the importance of volume of eroded material for cavitation erosion
PublikacjaW pracy przedstawiono model matematyczny opisujący wpływ objętości erodowanego materiału na przebieg krzywych erozji kawitacyjnej
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Cement kiln dust
PublikacjaThe volume of cement production in the world has remained at the level of approxi mately 4.1 billion tons/year. The cement production process is energy intensive and is the world’s leading emitter of carbon dioxide. Therefore, the main activities cement plants are aimed at introducing technologies changes in production of clinkier.The construction industry is responsible for the majority of CO2 emissions to the atmosphere: the...
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Finite element modelling of a historic church structure in the context of a masonry damage analysis
PublikacjaThe paper includes a case study of modelling a real historic church using the finite element method (FEM) based on laser scans of its geometry. The main goal of the study was the analysis of the causes of cracking and crushing of masonry walls. An FEM model of the structure has been defined in ABAQUS. A non-linear dynamic explicit analysis with material model including damage plasticity has been performed. A homogenization procedure...
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Low-dimensional bound entanglement with one-way distillable cryptographic key
PublikacjaIn this paper, we provide a class of bound entangled states that have positive distillable secure key rate. The smallest state of this kind is 4 circle times 4, which shows that peculiar security contained in bound entangled states does not need high-dimensional systems. We show that for these states a positive key rate can be obtained by one-way Devetak-Winter (DW) protocol. Subsequently, the volume of bound entangled key-distillable...
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Effect of Amino Acids and Sodium Chloride on d-Sorbitol in Aqueous Solutions at Different Temperatures: Volumetric and Acoustic Approach
PublikacjaApparent molar volumes and apparent molar compressibilities for d-sorbitol in (0.05, 0.1, 0.2 and 0.3) mol·kg−1 aqueous solutions of l-alanine, l-cysteine and l-histidine and NaCl have been determined from measurements of solution density at T = (288.15, 298.15, 308.15 and 318.15) K and sound velocity at T = 298.15 K, as a function of the concentration of the sugar alcohol. The data were used to obtain the limiting apparent molar...
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Pedestrian and bicycle bridges as examples of safe collision-free road crossings
PublikacjaPedestrians are most at risk when they are crossing the road. This represents a significant proportion of all fatalities among pedestrians, amounting respectively to 50% in non-built-up areas and 75% in built-up areas. The most frequent reason for this accident is failure to give way. What is most terrible is that 30% of pedestrian accidents occurred at marked pedestrian crossings. Therefore, an important part of pedestrian safety...
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Activated Carbon Produced by Pyrolysis of Waste Wood and Straw for PotentialWastewater Adsorption
PublikacjaPyrolysis of straw pellets and wood strips was performed in a fixed bed reactor. The chars, solid products of thermal degradation, were used as potential materials for activated carbon production. Chemical and physical activation processes were used to compare properties of the products. The chemical activation agent KOH was chosen and the physical activation was conducted with steam and carbon dioxide as oxidising gases. The eect...
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Experimental investigations of damage evolution in concrete during bending by continuous micro-CT scanning
PublikacjaThe paper describes experimental investigation results of fracture in notched concrete beams under quasi-static three-point bending. To visualize 3D fracture in concrete under bending, an extended X-ray micro-computed tomography system was used, i.e. the tomography system SkyScan 1173 was connected to the loading machine ISTRON 5569. This combined system enabled to shot images of deforming concrete beams during a continuous deformation...
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An isogeometric finite element formulation for frictionless contact of Cosserat rods with unconstrained directors
PublikacjaThis paper presents an isogeometric finite element formulation for nonlinear beams with impenetrability constraints, based on the kinematics of Cosserat rods with unconstrained directors. The beam cross-sectional deformation is represented by director vectors of an arbitrary order. For the frictionless lateral beam-to-beam contact, a surface-to-surface contact algorithm combined with an active set strategy and a penalty method...
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An isogeometric finite element formulation for geometrically exact Timoshenko beams with extensible directors
PublikacjaAn isogeometric finite element formulation for geometrically and materially nonlinear Timoshenko beams is presented, which incorporates in-plane deformation of the cross-section described by two extensible director vectors. Since those directors belong to the space R3, a configuration can be additively updated. The developed formulation allows direct application of nonlinear three-dimensional constitutive equations without zero...
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Measures of Functional Reliability of Two-Lane Highways
PublikacjaRural two-lane highways are the most common road type both in Poland and globally. In terms of kilometres, their length is by far greater than that of motorways and expressways. They are roads of one carriageway for each direction, which makes the overtaking of slower vehicles possible only when there is a gap in the stream of traffic moving from the opposite direction. Motorways and express roads are dual carriageways that are...
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Nitrogen removal via the nitrite pathway during wastewater co-treatment with ammonia-rich landfill leachates in a sequencing batch reactor
PublikacjaThe biological treatment of ammonia-rich landfill leachates due to an inadequate C to N ratio requires expensive supplementation of carbon from an external carbon source. In an effort to reduce treatment costs, the objective of the study was to determine the feasibility of nitrogen removal via the nitrite pathway during landfill leachate co-treatment with municipal wastewater. Initially, the laboratory-scale sequencing batch reactor...
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Investigations on fracture in reinforced concrete beams in 3-point bending using continuous micro-CT scanning
PublikacjaThis study explores a fracture process in rectangular reinforced concrete (RC) beams subjected to quasi-static three-point bending. RC beams were short and long with included longitudinal reinforcement in the form of a steel or basalt bar. The ratio of the shear span to the effective depth was 1.5 and 0.75. The focus was on the load–deflection diagram and crack formation. Three-dimensional (3D) analyses of the size and distribution...
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Rigid finite elements and multibody modelling used in estimation and reduction of rod vibrations
PublikacjaIn the paper, a mechanical set composed of a robot (manipulator) and of an elastic beam is considered. The beam is fixed to the top of the robot structure. In most of the similar cases, undesired vibrations can be excited in the beam. They are especially significant, when dynamics in the robot braking period is examined. In the paper, estimation and modification of length of the braking period is proposed, in order to reduce the...
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Parametric versus nonparametric modelling of dynamic susceptibility contrast enhanced MRI based data
PublikacjaDynamic tracking of a bolus of a paramagnetic agent (dynamic susceptibility contract - DSC) in MRI (magnetic resonance imaging) measurements is successfully used for assessment of the tissue perfusion and the other features and functions of the brain (i.e. cerebral blood flow - CBF, cerebral blood volume - CBV, mean transit time - MTT). The parametric and nonparametric approaches to the identification of MRI models are presented...
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Does one currency mean one price?
PublikacjaEuropean Monetary Union was expected to have many consequences for the economies of participant countries. Theory suggested that through a higher volume of trade and stronger competition in the Eurozone, a single currency would lead to a reduction in price dispersion. As far as prices are concerned, two effects were expected: an immediate effect due to the technical characteristics of the changeover process, and a long-term one...
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Application of lightweight cement composite with foamed glass aggregate in shell structures
PublikacjaThe purpose of the paper is to investigate the abilities of applying Granulated Expanded Glass Aggregate (GEGA) as a natural volume substitute of aggregate as a component of lightweight concrete. The GEGA aggregates used in the experiments were made of confused glass waste. In order to achieve satisfactory strength of concrete Granulated Ash Aggregate (GAA) was added as well. To produce specimens three grain sizes of aggregates...
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Extended phase diagram of RNiC2 family: Linear scaling of the Peierls temperature
PublikacjaPhysical properties for the late-lanthanide-based RNiC2 (R = Dy, Ho, Er, and Tm) ternary compounds are reported. All the compounds show antiferromagnetic ground state with the Néel temperature ranging from 3.4 K for HoNiC2 to 8.5 K for ErNiC2. The results of the transport and galvanomagnetic properties confirm a charge density wave state at and above room temperature with transition temperatures TCDW = 284, 335, 366, and 394 K for...
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INFORMATION SOCIETY DEVELOPMENT TRENDS, FROM DATA THROUGH KNOWLEDGE TO WISDOM
PublikacjaThe paper investigates both the causes and effects of the rapid increase in the data volume(BigData)andtheirimpactonhumancognition.TheroleoftheInternetindistributing and exchanging of such data, and their impact on the growth of the Information Society are emphasized. As a result, Wisdom Science – a new kind of research – emerges which has the potential to facilitate more advanced solutions in the digital world. In consequence,...
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Influence of Wastewater Treatment Technology on Particle Size Distribution in the Effluent
PublikacjaSuspended solids in water and wastewater usually carry quite a large load of pollutants (organic substances, nutrients, heavy metals, etc.) adsorbed on the particles surface. Particles of different sizes carry different types and quantities of pollutants. Therefore, particle size distribution is of importance in waster and wastewater treatment. In the article the influence of different treatment technologies on particle size distribution...
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Composites of tin oxide and different carbonaceous materials as negative electrodes in lithium-ion batteries
PublikacjaAbstract Tin and tin oxide have been considered as suitable materials with high theoretical capacity for lithium ion batteries. Their low cost, high safety and other technical benefits placed them as promising replacements for graphite negative electrodes. The problem to overcome with tin oxide, as well as with other metallic materials, is high volume changes during alloying/dealloying, subsequent pulverization, delamination from...
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Deep learning for recommending subscription-limited documents
PublikacjaDocuments recommendation for a commercial, subscription-based online platform is important due to the difficulty in navigation through a large volume and diversity of content available to clients. However, this is also a challenging task due to the number of new documents added every day and decreasing relevance of older contents. To solve this problem, we propose deep neural network architecture that combines autoencoder with...
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Analysis of Factors Influencing the Prices of Tourist Offers
PublikacjaTourism is a significant branch of many world economies. Many factors influence the volume of tourist traffic and the prices of trips. There are factors that clearly affect tourism, such as COVID-19. The paper describes the methods of machine learning and process mining that allow for assessing the impact of various factors (micro, mezzo and macro) on the prices of tourist offers. The methods were used on large sets of real data...
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On Effective Bending Stiffness of a Laminate Nanoplate Considering Steigmann–Ogden Surface Elasticity
PublikacjaAs at the nanoscale the surface-to-volume ratio may be comparable with any characteristic length, while the material properties may essentially depend on surface/interface energy properties. In order to get effective material properties at the nanoscale, one can use various generalized models of continuum. In particular, within the framework of continuum mechanics, the surface elasticity is applied to the modelling of surface-related...
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Can unequal distributions of wealth influence vote choice? A comparative study of Germany, Sweden and the United States.
PublikacjaIt is widely accepted that income influences voting behavior. Does wealth? Is the effect similar across countries? Studies of wealth and voting behavior have not existed until recently, in part because of the absence of data on wealth holdings. The findings in this chapter indicate that wealth is related to voting behavior in some countries but not in others. The chapter models the effects of wealth on one form of voting behavior,...
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Experimental study on the selected aspects of bow thruster generated flow field at ship zero-speed conditions
PublikacjaThe paper presents the results of experimental study on the interaction between the bow thrusters understood as the flow field changes generated by bow tunnel thruster in deep water conditions operated as a single and twin units. The research was limited to zero-speed case for the ship dead in the water. The influence of the hull form and jet spread between the neighbouring thrusters for several combinations of the applied bow...
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Updating Finite Element Model of a Wind Turbine Blade Section Using Experimental Modal Analysis Results
PublikacjaThis paper presents selected results and aspects of themultidisciplinary and interdisciplinary research oriented for the experimental and numerical study of the structural dynamics of a bend-twist coupled full scale section of awind turbine blade structure.Themain goal of the conducted research is to validate finite elementmodel of themodified wind turbine blade section mounted in the flexible support structure accordingly to the...
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Finite-state lexical tools
PublikacjaArtykuł przedstawia trzy pakiety oprogramowania zawierające narzędzia poziomu leksykalnego wykorzystujące automaty skończone: dwa zbiory samodzielnych programów i skryptów pomocniczych - jeden używający prostych automatów skończonych, drugi używający automatów Mealy`ego oraz bibliotekę funkcji. Wszystkie przedstawione pakiety posiadają podobne funkcje. Zamiast opisywać poszczególne pakiety, opis skupiony jest na dostarczanych przez...
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Hybrid Method Analysis of Unshielded Guiding Structures
PublikacjaA combination of mode matching, finite element methods and generalized impedance matrix is presented in a context of propagation problems for open guiding structures. The computational domain is divided into two regions: the first one is a circular cylinder containing whole guiding structure and the second one surrounds this artificial cylinder. The impedance matrix is calculated with the use of finite element method in the first...
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Computed tomography indicators of cerebral microperfusion improve long term after carotid stenting in symptomatic patients
PublikacjaOBJECTIVES: We tested the hypothesis that computed tomography (CT) perfusion markers of cerebral microcirculation would improve 36 months after internal carotid artery stenting for symptomatic carotid stenosis while results obtained 6-8 weeks after the stenting procedure would yield a predictive value. METHODS: We recruited consecutive eligible patients with >70% symptomatic carotid stenosis with a complete circle of Willis and...
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Does Tempo of Resistance Exercise Impact Training Volume?
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Representative volume element in 2D for disks and in 3D for balls
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Economic Foundations for Creative Ageing Policy, Volume II
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Economic Foundations for Creative Ageing Policy, Volume I
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Gray matter volume in relation to cardio-vascular stiffness
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An Efficient Simulation Method of Massive MIMO Antenna Arrays used in 5G Mobile Phones
PublikacjaThis paper deals with a model-order reduction method, applied to speed-up the simulations of MIMO antenna arrays, performed by means of finite element method. The obtained results of the numerical tests show that the described technique is reliable and considerably increases the efficiency of the standard finite element method.
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INFOGEST inter-laboratory recommendations for assaying gastric and pancreatic lipases activities prior to in vitro digestion studies
PublikacjaIn vitro digestion studies often use animal digestive enzyme extracts as substitutes of human gastric and pancreatic secretions. Pancreatin from porcine origin is thus commonly used to provide relevant pancreatic enzymes such as proteases, amylase and lipase. Rabbit gastric extracts (RGE) have been recently introduced to provide gastric lipase in addition to pepsin. Before preparing simulated gastric and pancreatic extracts with...
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The Influence of Cement Type on Early Properties of Cold In-Place Recycled Mixtures
PublikacjaCold in-place recycling is a commonly used maintenance treatment in rehabilitation of low and medium volume roads in Poland. Typically, two types of binding agents are used—cement and bituminous emulsion (or foamed bitumen).Due to the harsh Polish climate with many freeze/thaw cycles and frequent occurrence of saturated conditions, the used amounts of cement are higher than those commonly used in warmer parts of Europe. While there...
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Biomechanics of Lumbar Spine Injury in Road Barrier Collision–Finite Element Study
PublikacjaLiterature and field data from CIREN database have shown that lumbar spine injuries occur during car crashes. There are multiple hypotheses regarding how they occur; however, there is no biomechanical explanation for these injuries during collisions with road safety barriers (RSBs). Therefore, the objective of this study was to investigate the mechanics of vertebral fractures during car collisions with concrete RSBs. The finite...
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Inline Waveguide Filter With Compact Frequency-Dependent Coupling Producing Two Additional Poles and Three Transmission Zeros
PublikacjaThis work reports a compact frequency-dependent coupling (FDC) structure introduced in a rectangular waveguide, which allows to generate two additional in-band transmission poles and three transmission zeros (TZs). This serves to increase the order/selectivity of the waveguide bandpass filter in a compact inline topology, thus without the need for any additional space/volume or cross coupling. The proposed FDC consists of a partial-height...
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Organizational Resilience in Hospitality and Tourism
PublikacjaAlthough ‘VUCA’ is not a new term, the features of the world it describes, a volatile, uncertain, complex and ambiguous environment, have never been more valid. The VUCA world has become the new reality for business, specifically for hospitality and tourism organizations that are more vulnerable than any other sector due to the historically-recognized turbulent environment in which they operate. In this book, the authors present...
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Charge density wave and large nonsaturating magnetoresistance in YNiC2 and LuNiC2
PublikacjaWe report a study of physical properties of two quasi-low-dimensional metals YNiC2 and LuNiC2 including the investigation of transport, magnetotransport, galvanomagnetic, and specific heat properties. In YNiC2 we reveal two subsequent transitions associated with the formation of weakly coupled charge density wave at TCDW=318K and its locking in with the lattice at T1=275K. These characteristic temperatures follow the previously...
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Sensitivity analysis of free torsional vibration frequencies of thin-walled laminated beams under axial load
PublikacjaThe paper addresses sensitivity analysis of free torsional vibration frequencies of thin-walled beams of bisymmetric open cross-section made of unidirectional fibre-reinforced laminate. The warping effect and the axial end load are taken into account. The consideration is based upon the classical theory of thin-walled beams of non-deformable cross-section. The first-order sensitivity variation of the frequencies is derived with...
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Enhancement of fiber-optic low-coherence Fabry-Pérot interferometer with ZnO ALD films
PublikacjaIn this paper investigation of the enhanced fiber-optic low coherence Fabry-Pérot interferometer with zinc oxide (ZnO) film deposited by atomic layer deposition (ALD) was presented. Model of the interferometer, which was constructed of single-mode optical fiber with applied ZnO ALD films, was built. The interferometer was also examined by means of experiment. Measurements were performed for both reflective and transmission modes,...
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New procedure for the examination of the degradation of volatile organonitrogen compounds during the treatment of industrial effluents
PublikacjaWe present a new procedure for the determination of 32 volatile organonitrogen compounds in samples of industrial effluents with a complex matrix. The procedure, based on dispersive liquid–liquid microex-traction followed by gas chromatography with nitrogen-phosphorus and mass spectrometric detection, wasoptimized and validated. Optimization of the extraction included the type of extraction and disperser sol-vent, disperser solvent...