Filtry
wszystkich: 2141
wybranych: 1464
-
Katalog
- Publikacje 1464 wyników po odfiltrowaniu
- Czasopisma 122 wyników po odfiltrowaniu
- Konferencje 7 wyników po odfiltrowaniu
- Wydawnictwa 1 wyników po odfiltrowaniu
- Osoby 17 wyników po odfiltrowaniu
- Wynalazki 5 wyników po odfiltrowaniu
- Projekty 2 wyników po odfiltrowaniu
- Zespoły Badawcze 1 wyników po odfiltrowaniu
- Kursy Online 29 wyników po odfiltrowaniu
- Wydarzenia 10 wyników po odfiltrowaniu
- Dane Badawcze 483 wyników po odfiltrowaniu
Filtry wybranego katalogu
wyświetlamy 1000 najlepszych wyników Pomoc
Wyniki wyszukiwania dla: COGNITIVE RADIO
-
Detection, classification and localization of acoustic events in the presence of background noise for acoustic surveillance of hazardous situations
PublikacjaEvaluation of sound event detection, classification and localization of hazardous acoustic events in the presence of background noise of different types and changing intensities is presented. The methods for discerning between the events being in focus and the acoustic background are introduced. The classifier, based on a Support Vector Machine algorithm, is described. The set of features and samples used for the training of the...
-
Nagranie formy muzycznej w systemie stereofonii dookólnej
PublikacjaCelem pracy była realizacja nagrania kwintetu jazzowego w wybranych systemach stereofonii wielokanałowej. Dodatkowym celem było przeprowadzenie testów subiektywnych zrealizowanych nagrań. W pracy zawarto w pierwszej kolejności zagadnienia związane z przestrzenną lokalizacją źródeł dźwięku przez człowieka. W dalszej części przywołane zostały wybrane techniki mikrofonowe stereofonii wielokanałowej, a także metody prowadzenia testów...
-
Design and optimization of a novel miniaturized low-profile circularly polarized wide-slot antenna
PublikacjaThis paper presents a novel structure of a compact circularly polarized (CP) antenna. CP is obtained using a parasitic quasi-rectangular strip placed coplanar to the feedline. A ground plane perturbation combined with the asymmetric geometry of the coplanar waveguide ground planes is utilized to excite additional CP modes. All antenna dimensions are rigorously optimized to achieve the best possible performance in terms of the impedance...
-
STUDY ON THE EFFECTIVENESS OF THE TURBINE CONDENSER AIR EXTRACTION SYSTEM USING HYDRO EJECTORS
PublikacjaThe aim of the paper is to investigate the effectiveness of the 18K380 steam turbine condenser air extraction system using hydro ejectors. Motivation for the analysis is a need of improvement of the energy conversion ratio of the power plant. To achieve this goal it is necessary to establish efficiency of each subsystem of the energy cycle. The air extraction system is not a highly power consuming system but it has great impact...
-
The mechanical properties and bactericidal degradation effectiveness of tannic acid-based thin films for wound care
PublikacjaThe surface area is the most important aspect when considering the interactions between a material and the surrounding environment. Chitosan (CTS) and tannic acid (TA) were previously successfully tested by us to obtain thin films to serve as wound dressings or food packaging materials. However, surface properties as well as the antimicrobial activity of the material were not considered. They are important if the material is likely...
-
Comparative study of operation of condensing and traditional boilers equipped with the ORC module for electricity generation
PublikacjaCondensing technology applied to boilers is to make full use of thermal energy contained in the fuel. That means that additionaly the heat from condensation of exhaust gases can be used for the purposes of heating the domestic hot water and to cover the demand for central heating. The study analyzed the operation of the "traditional" boiler equipped with the ORC module as the similar arrangement but with the condensing boiler....
-
On-line Search in Two-Dimensional Environment
PublikacjaWe consider the following on-line pursuit-evasion problem. A team of mobile agents called searchers starts at an arbitrary node of an unknown network. Their goal is to execute a search strategy that guarantees capturing a fast and invisible intruder regardless of its movements using as few searchers as possible. As a way of modeling two-dimensional shapes, we restrict our attention to networks that are embedded into partial grids:...
-
QoS Extensions for Flow-Awareness Networks
PublikacjaThe paper contains a description and research results of the proposal for distributed QoS extensions for Flow-Based Networking. These QoS extensions let the network accept or reject flows based on current network load and QoS promises for each of the flows. Proposed solution consists of two distributed components, each of them performing in every node, measurement system and access control. The solution could be applied in any...
-
Fabrication of toughened plastic using styrene butadiene rubber-poly (methyl methacrylate) interpenetrating polymer networks
PublikacjaA standard set of interpenetrating polymeric networks (IPNs) has been contrived using an elastomerstyrene butadiene rubber and a thermoplastic poly (methyl methacrylate) through sequential polymerization protocol. This low-cost material can be hopefully engaged as a toughened plastic with cocontinuous morphology. Different morphological protocols including Raman imaging are effectively utilized to envisage the effect of blend ratio...
-
Experimental study of the effect of vertical acceleration component on the slope stability
PublikacjaThe paper deals with the stability of earth dams subjected to seismic and paraseismic excitations occurring in the close distance to the dam. The Newmark’s stability approach, classified as a simplified dynamic method, has been extended for two directional dynamic loading case and the evolution of the friction coefficient. The paper is focused on the experimental verification of the proposed method for harmonic and cyclic excitations...
-
Adsorption-assisted transport of water vapour in super-hydrophobic membranes filled with multilayer graphene platelets
PublikacjaThe effects of confinement of multilayer graphene platelets in hydrophobic microporous polymeric membranes are here examined. Intermolecular interactions between water vapour molecules and nanocomposite membranes are envisaged to originate assisted transport of water vapour in membrane distillation processes when a suitable filler-polymer ratio is reached. Mass transport coefficients are estimated under different working conditions,...
-
Structure and transport properties of donor-doped barium strontium cobaltites
PublikacjaIn this work, Nb-substituted barium strontium cobaltites Ba0.5Sr0.5Co1-xNbxO3-δ (x = 0 – 0.4) have been fabricated and studied. The structural analysis showed that the Nb content influences the lattice constant as well as the distance between the (Co, Nb) and oxygen atoms. The study of morphology of samples showed that the Nb content does not change the porosity, grain size and morphology of the ceramics. The total electrical conductivity...
-
Degradation of 1,4-dioxane by sono-activated persulfates for water and wastewater treatment applications
PublikacjaThis paper presents a hybrid advanced oxidation process (AOP) based on sonocavitational activation of persulfate (PS) for degradation of 1,4-dioxane during wastewater treatment. Application of sono-cavitation effectively convert PS to radical species demonstrating synergistic effect by increasing the reaction rate and reducing the required energy for activation. It is economically feasible and deployed alternative to the direct...
-
Hybrid cross-linked chitosan/protonated-proline:glucose DES membranes with superior pervaporation performance for ethanol dehydration
PublikacjaThis work explores a protonated L-proline:glucose (molar ratio 5:1) deep eutectic solvent (DES) in fabricating biopolymer membranes utilizing chitosan (CS). Initially, the miscibility of CS and DES to prepare homogeneous dense blend membranes has been investigated. Different techniques, such as scanning electron microscopy, contact angle (CA), atomic force microscopy (AFM), Fourier transformed infrared spectroscopy (FTIR) and swelling...
-
Energy neutrality versus carbon footprint minimization in municipal wastewater treatment plants
PublikacjaThis work aimed to compare the carbon footprint (CF) of six full-scale wastewater treatment plants (WWTPs). The CF was estimated in the range of 23–100 kg CO2e per population equivalent. In the total CF, the direct emissions held the highest share (62–74%) for the plants with energy recovery from biogas. In the plants depending entirely on the power grid, the indirect emissions due to energy consumption dominated the total CF (69–72%)....
-
Thermal Buckling Analysis of Circular Bilayer Graphene sheets Resting on an Elastic Matrix Based on Nonlocal Continuum Mechanics
PublikacjaIn this article, the thermal buckling behavior of orthotropic circular bilayer graphene sheets embedded in the Winkler–Pasternak elastic medium is scrutinized. Using the nonlocal elasticity theory, the bilayer graphene sheets are modeled as a nonlocal double–layered plate that contains small scale effects and van der Waals (vdW) interaction forces. The vdW interaction forces between the layers are simulated as a set of linear springs...
-
A systematic review on cellular responses of Escherichia coli to nonthermal electromagnetic irradiation
PublikacjaInvestigation of Escherichia coli under electromagnetic fields is of significance in human studies owing to its short doubling time and human‐like DNA mechanisms. The present review aims to systematically evaluate the literature to conclude causality between 0 and 300 GHz electromagnetic fields and biological effects in E. coli. To that end, the OHAT methodology and risk of bias tool were employed. Exponentially growing cells exposed...
-
The influence of electromagnetic pollution on living organisms – historical trends and forecasting changes
PublikacjaCurrent technologies have become a source of omnipresent electromagnetic pollution from generated electromagnetic fields and resulting electromagnetic radiation. In many cases this pollution is much stronger than any natural sources of electromagnetic fields or radiation. Wireless and radio communication, electric power transmission or devices in daily use such as smartphones, tablets and portable computers every day expose people...
-
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...
-
Universal autonomous control and management system for multipurpose unmanned surface vessel
PublikacjaThe paper presents design, structure and architecture of the Universal Autonomous Control and Management System (UACAMS) for multipurpose unmanned surface vessel. The system was designed, installed and implemented on the multipurpose platform - unmanned surface vessel named HydroDron. The platform is designed to execute hydrographic survey missions with multi-variant configuration of the survey system (payload? ) including multi-beam...
-
High gain/bandwidth off‑chip antenna loaded with metamaterial unit‑cell impedance matching circuit for sub‑terahertz near‑field electronic systems
PublikacjaAn innovative off-chip antenna (OCA) is presented that exhibits high gain and efficiency performance at the terahertz (THz) band and has a wide operational bandwidth. The proposed OCA is implemented on stacked silicon layers and consists of an open circuit meandering line. It is shown that by loading the antenna with an array of subwavelength circular dielectric slots and terminating it with a metamaterial unit cell, its impedance...
-
Relationship between GIX, SIDX, and ROTI ionospheric indices and GNSS precise positioning results under geomagnetic storms
PublikacjaIonospheric indices give information about ionospheric perturbations, which may cause absorption, diffraction, refraction, and scattering of radio signals, including those from global navigation satellite systems (GNSS). Therefore, there may be a relationship between index values and GNSS positioning results. A thorough understanding of ionospheric indices and their relationship to positioning results can help monitor and forecast...
-
Zastosowanie addytywów w separacji pianowej białek serwatkowych i białek mlecznych
PublikacjaZaproponowano proces separacji pianowej do wydzielania białek ze strumieni poprodukcyjnych przemysłu mleczarskiego Ponadto zaproponowano zastosowanie w separacji pianowej białek serwatkowych i mlecznych addytywów dopuszczonych ustawą do stosowania w żywności. Jako cel pracy przyjęto uzyskanie wyników uzasadniających wybór takich addytywów, które intensyfikują przebieg i polepszają wynik procesu separacji pianowej białek. W części...
-
Can augmented democracy fulfil the ideal of deliberative democracy?
PublikacjaNew technologies can broaden the scope of human limits. We can fly to the moon thanks to rocket science, we can communicate with each other by mobile phones and WiFi and we can exceed human life with medical equipment like pacemakers. But there are aspects of our life that still are very distrustful of implementing new technology into functioning. An example of such a field of our everyday life is...
-
URBAN MENTORING JAKO NOWA TECHNIKA WPRÓŁPRACY W PROCESIE PLANOWANIA PARTCYPACYJNEGO
PublikacjaW 25 lat od powrotu demokracji opierającej się o neoliberalny paradygmat rozwoju kraju, Polska przyjęła Krajową Politykę Miejską 2030. Wraz z ustawą o rewitalizacji w nowoczesny sposób określa ona pole współpracy władz samorządowych i administracji z mieszkańcami, przejście do drugiej fazy rozwoju społeczeństwa demokratycznego – mieszkańców współgospodarzy przestrzeni miast. Powolna ewolucja tej relacji, silnie obarczonej dziedzictwem...
-
Wpływ ścieków przemysłowych na energochłonność i efektywność procesów technologicznych w komunalnej oczyszczalni ścieków
PublikacjaW artykule skupiono się na przedstawieniu wpływu jakości i ilości ścieków przemysłowych wprowadzanych do sieci kanalizacyjnej PEWIK GDYNIA Sp. z o. o. na stabilność procesów technologicznych. Określono również wpływ ścieków przemysłowych na energochłonność i efektywność oraz na wzrost kosztów oczyszczania ścieków komunalnych w Grupowej Oczyszczalni Ścieków „Dębogórze” w latach 2012-2015.
-
Uniwersalny program komputerowy do projektowania zmiany kierunku trasy
PublikacjaW pracy przedstawiono kolejny program komputerowy stanowiący implementację algorytmu obliczeniowego dotyczącego projektowania zmiany kierunku trasy kolejowej, dostosowanego do techniki ciągłych pomiarów satelitarnych. Program ten ma charakter uniwersalny, gdyż w ogólnym przypadku obejmuje wprowadzenie do układu geometrycznego dwóch łuków kołowych o różnym promieniu, czyli zastosowanie łuku koszowego. Może się to okazać szczególnie...
-
Wykorzystanie sztucznych sieci neuronowych do wykrywania i rozpoznawania tablic rejestracyjnych na zdjęciach pojazdów
PublikacjaW artykule przedstawiono koncepcję algorytmu wykrywania i rozpoznawania tablic rejestracyjnych (AWiRTR) na obrazach cyfrowych pojazdów. Detekcja i lokalizacja tablic rejestracyjnych oraz wyodrębnienie z obrazu tablicy rejestracyjnej poszczególnych znaków odbywa się z wykorzystaniem podstawowych technik przetwarzania obrazu (przekształcenia morfologiczne, wykrywanie krawędzi) jak i podstawowych danych statystycznych obiektów wykrytych...
-
Determination of nine high-intensity sweeteners in various foods by high-performance liquid chromatography with mass spectrometric detection
PublikacjaAn analytical procedure involving solid-phase extraction (SPE) and high-performance liquid chromatography-mass spectrometry has been developed for the determination of nine high-intensity sweeteners authorised in the EU; acesulfame-K (ACS-K), aspartame (ASP), alitame (ALI), cyclamate (CYC), dulcin (DUL), neohesperidin dihydrochalcone (NHDC), neotame (NEO), saccharin (SAC) and sucralose (SCL) in a variety of food samples (i.e. beverages,...
-
Unusual dynamics and nonlinear thermal self-focusing of initially focused magnetoacoustic beams in a plasma
PublikacjaUnusual thermal self-focusing of two-dimensional beams in plasma which axis is parallel to the equilibrium straight magnetic field is considered. The equi- librium parameters of plasma determine scenario of a beam divergence (usual or unusual) which is stronger as compared with a flow without magnetic field. Nonlinear thermal self-action of a magnetosonic beam behaves differently in the ordinary and unusual cases. Damping of wave...
-
Analytical predictions for the buckling of a nanoplate subjected to non-uniform compression based on the four-variable plate theory
PublikacjaIn the present study, the buckling analysis of the rectangular nanoplate under biaxial non-uniform compression using the modified couple stress continuum theory with various boundary conditions has been considered. The simplified first order shear deformation theory (S-FSDT) has been employed and the governing differential equations have been obtained using the Hamilton’s principle. An analytical approach has been applied to obtain...
-
Synergistic effects of nitrogen-doped carbon and praseodymium oxide in electrochemical water splitting
PublikacjaHybrid materials featuring perovskite-type metal oxide in conjunction with heteroatom-doped graphene hold immense promise as alternatives to costly noble metal catalysts for electrochemical water splitting, facilitating the generation of environmentally friendly hydrogen. In this study, perovskite-type oxide containing praseodymium, barium, strontium, cobalt, and iron atoms dispersed in a carbon matrix as a catalyst is synthesized...
-
Hybrid all-cellulose reinforcement in polypropylene matrix biocomposites for injection moulding - influence of particle geometry and volume fraction on hybrid effect
PublikacjaThe presented study is focused on evaluation of influence of reinforcement volume fraction and geometry on the occurrence of positive hybrid effect by the hybridisation of man-made cellulose fibres (rayon viscose) with cellulose microparticle fillers applied in polypropylene matrix. Four volume fractions of reinforcement were used at 1:1 combination of short man-made cellulose fibres with cellulose microfillers of different aspect...
-
Study on effective front region thickness of PCM in thermal energy storage using a novel semi-theoretical model
PublikacjaThermal energy storage in mobile applications, particularly battery of electric vehicles, is currently gaining a lot of importance. In this paper, a semi-theoretical time-dependent mathematical model of the phase change in a double shell thermal energy storage module has been developed where the inner tube is a heat exchange surface. An effective front region thickness for the melting and solidification process has been studied....
-
Electro-mechanical shear buckling of piezoelectric nanoplate using modified couple stress theory based on simplified first order shear deformation theory
PublikacjaThis paper studies the electro-mechanical shear buckling analysis of piezoelectric nanoplate using modified couple stress theory with various boundary conditions.In order to be taken electric effects into account, an external electric voltage is applied on the piezoelectric nanoplate. The simplified first order shear deformation theory (S-FSDT) has been employed and the governing differential equations have been obtained using...
-
Electroelastic biaxial compression of nanoplates considering piezoelectric effects
PublikacjaIn the present theoretical work, it is assumed that a piezoelectric nanoplate is connected to the voltage meter which voltages have resulted from deformation of the plate due to in-plane compressive forces whether they are critical buckling loads or arbitrary forces. In order to derive governing equations, a simplified four-variable shear deformation plate theory has been employed using Hamilton’s principle and Von-Kármán...
-
Influence of pyrolysis atmosphere on the lithium storage properties of carbon-rich polymer derived SiOC ceramic anodes
PublikacjaPolymer derived carbon-rich SiOC ceramics are prepared from polysiloxane precursors through a pyrolysis process at 1000 °C using pure argon and argon/hydrogen mixture as pyrolysis atmosphere. The precursor is synthesized from a linear (Si–H)-containing polysiloxane cross-linked with divinylbenzene using hydrosilylation reaction in the presence of a platinum catalyst. Pyrolysis in Ar/H2 mixtures, compared to the treatment under...
-
Wpływ mikrosfer-frakcji odpadów paleniskowych na mikrostrukturę i wybrane właściwości uzytkowe
PublikacjaIn this study, the microspheres samples were collected from national power station „Dolna Odra”. In this study, the following materials were used: Portland cement class 32,5R and aggregates of 2-8 and 8-16 fractions and natural sand with a maximum grain size of 2 mm and water. Concrete mixtures were made with microspheres additions of 15%, 25% and 40%. A constant water to binder ratio (w/b) of 0,52 was used throughout the investigation....
-
A Regular Expression Matching Application with Configurable Data Intensity for Testing Heterogeneous HPC Systems
PublikacjaModern High Performance Computing (HPC) systems are becoming increasingly heterogeneous in terms of utilized hardware, as well as software solutions. The problems, that we wish to efficiently solve using those systems have different complexity, not only considering magnitude, but also the type of complexity: computation, data or communication intensity. Developing new mechanisms for dealing with those complexities or choosing an...
-
Navier number and transition to turbulence
PublikacjaThe motivation behind this article is to explain a role of the Navier number (Na -dimensionless slip-length) in prediction of closures for laminar to turbulent transition undergoing via eddies detachment from the slip layer in nano-cannals. Additionally the role of the Navier number Na in universal modeling of phenomenon of enhanced mass flow rate reported in micro- and nano-channels has been explained. The Na number should be...
-
Verification of Selected Calculation Methods Regarding Shear Strength in Reinforced and Prestressed Concrete Beams
PublikacjaThe purpose of this article was an attempt to compare selected calculation methods regarding shear strength in reinforced and prestressed concrete beams. Several calculation methods were tested. This included codes: PN-EN 1992-1-1:2008 [1], ACI 318- 14 [2] and fib Model Code for Concrete Structures 2010 [3]. The analysis also consists of methods published in technical literature. Calculations of shear strengths were made based...
-
Structure and electrical properties of Y, Fe-based perovskite mixed conducting composites fabricated by a modified polymer precursor method
PublikacjaIn this work, samples of Y0.07Sr0.93Ti1-xFexO3-d with 20, 40, 60 and 80 mol% of iron amount were prepared by a low-temperature polymer precursor method. The SEM-EDS analysis proved that analyzed Y0.07Sr0.93Ti1-xFexO3-d samples were composites of two Ti- and Fe-rich perovskite samples. This kind of composite consists of two phases in which one has a good ionic and the other electronic conductivity, which makes such a composite a...
-
MATCHED FILTER APPROACH FOR MICROSEISMIC SIGNAL PROCESSING OF REAL DATA FROM EAST POMERANIA SHALE GAS
PublikacjaThe microseismic monitoring is a method of monitoring of fracture propagation during hydraulic fracturing (HF)process. An array of several hundred geophones is placed on the surface to record little ground tremors induced by fracturing process. Filtration and summation of signals from geophones is essential to identify and locate fracturing events from underground. Authors propose a method of matched filtering, that is usually...
-
Comparison of Downdraft and Updraft Gasification of Biomass in a Fixed Bed Reactor
PublikacjaThe aim of this study was to compare and analyze the gasification process of beech wood. The experimental investigation was conducted inside a gasifier, which can be operated in downdraft and updraft gasification system. The most important operating parameter studied in this paper was the influence of the amount of supply air on the temperature distribution, biomass consumption and syngas calorific value. The results show that...
-
Improvement of opipramol base solubility by complexation with β-cyclodextrin
PublikacjaOpipramol (OPI), a tricyclic antidepressant and anxiolytic compound, is administered orally in the form of a dihydrochloride. Salt form of the drug has a higher solubility in water and hence bioavailability and stability. A similar effect can be achieved by closing the hydrophobic part of the drug molecule in the cyclodextrin cavity. The paper presents opipramol inclusion complexes with beta-cyclodextrin (β-CD) in 1:1 molar ratio....
-
Meconium analysis as a promising diagnostic tool for monitoring fetal exposure to toxic substances: Recent trends and perspectives
PublikacjaPrenatal exposure to toxic substances is an important public health problem. Many biological specimens obtained from the fetus or mother are used for biomonitoring. Each material reflects exposure in a specific time period and has different advantages and disadvantages in terms of accuracy, time window of detection and cost/benefit ratio. Recently, meconium has become the matrix of choice in toxicology screening for detecting exposure...
-
Syntheses, Structures and Reactivity of Terminal Phosphido Complexes of Iron(II) Supported by a β-Diketiminato Ligand
PublikacjaWe report the synthesis of the first series of terminal phosphido iron complexes supported by a β‐diketiminato ligand (Dippnacnac) and their catalytic activity in dehydrocoupling of secondary phosphines. Anionic and neutral mono‐ or diphosphido complexes were obtained from the reaction of [(Dippnacnac)FeCl2Li(dme)2] with the R2PLi (R = iPr, tBu, Cy, Ph) phosphides by tuning the stoichiometric ratio, polarity of the solvent, and...
-
Statistical analysis and robust design of circularly polarized antennas using sequential approximate optimization
PublikacjaIn the paper, reliable yield estimation and tolerance-aware design optimization of circular polarization (CP) antennas is discussed. We exploit auxiliary kriging interpolation models established in the vicinity of the nominal design in order to speed up the process of statistical analysis of the antenna structure at hand. Sequential approximate optimization is then applied to carry out robust design of the antenna, here, oriented...
-
Novel bio-based thermoplastic poly(ether-urethane)s. Correlations between the structure, processing and properties
PublikacjaThe main purpose of this work was to analyze the effect of the number of unreacted isocyanate groups and the [NCO]/[OH] molar ratio during the chain extension of a prepolymer during the polymerization process on the structure, processing and selected properties of thermoplastic poly(ether-urethane)s. Three series of novel thermoplastic polyurethanes were obtained via a prepolymer route. Three prepolymers were synthesized from diisocyanate...
-
Suppression of distortions in signals received from Doppler sensor for vehicle speed measurement
PublikacjaDoppler sensors are commonly used for movement detection and speed measurement. However, electromagnetic interference and imperfections in sensor construction result in degradation of the signal to noise ratio. As a result, detection of signals reflected from moving objects becomes problematic. The paper proposes an algorithm for reduction of distortions and noise in the signal received from a simple, dual-channel type of a Doppler...