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Wyszukujesz frazę "Kowalczuk, P." wg kryterium: Autor


Tytuł:
Sky glint correction in measurements of upward radiance above the sea surface
Autorzy:
Olszewski, J.
Kowalczuk, P.
Powiązania:
https://bibliotekanauki.pl/articles/48314.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
marine optics
coastal water
remote sensing
glint reduction
ocean water
sea surface
Opis:
An experiment has been performed to determine the upward water-leaving radiance by non-contact measurement of the total upward and downward radiance above the sea surface from a moving ship. The method for achieving this aim is described: the radiance meters are both tilted in such a way that the upward radiance meter can ‘see’ that part of the measured downward radiance which would be reflected if the water surface were smooth and which is not derived directly from solar glitter. Both meters are firmly fixed in a special frame, which ensures that the required orientation is the most probable one. Time records of the measured parameters are analysed. The results are presented in several forms: frequency (histogram) analysis appears to be the most promising one.
Źródło:
Oceanologia; 2000, 42, 2
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of statistical process control for proper processing of the Fore-Sudetic Monocline copper ore
Autorzy:
Tasdemir, A.
Kowalczuk, P. B.
Powiązania:
https://bibliotekanauki.pl/articles/110236.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
copper
upgrading
statistical process control
ARIMA model
Shewhart’s chart
autocorrelation
Opis:
The paper deals with Statistical Process Control (SPC) applied to three original and three generated variables of copper ore upgrading by flotation. The six variables were evaluated by the SPC charts based on industrial upgrading of copper ore data gathered during one month of operation in the form of copper content in feed, concentrate and tailing. The remaining three upgrading variables were concentrate yield, copper recovery in concentrate and non-copper components recovery in tailing. Although, all variables obeyed normal distribution, considerable autocorrelation was detected between observations for all variables. For this reason, the traditional Shewhart control charts, that assume the process data generated are normally and independently distributed, resulted in many of out-of-control points which may lead to wrong decisions regarding the control of process variables. The most suitable ARIMA time series models were determined for all variables to remove autocorrelations. The ARIMA(0,1,1) model was found the best for copper content in feed, copper content in concentrate, concentrate yield and non-copper components recovery in tailing, while the AR(1) model was suitable for copper content in tailing and copper recovery in concentrate.
Źródło:
Physicochemical Problems of Mineral Processing; 2014, 50, 1; 249-264
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some remarks on attachment of a gas bubble to another phase both immersed in water
Autorzy:
Kowalczuk, P. B.
Drzymala, J.
Powiązania:
https://bibliotekanauki.pl/articles/110908.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
hydrophobicity
aquaoleophobicity
contact angle
liquid film
attachment
Opis:
In this paper the importance of definition of hydrophobicity and aquaoleophilicity in terms of contact angle as well as the properties of water films in flotation and oil agglomeration were briefly presented. It was shown that the hysteresis of contact angle for a considered system depends on the way of measurement and geometry of the system due to the presence of other that excess pressure and capillary forces and buffering properties of the capillary force. It was suggested that, the measured advancing and receding contact angles should be, when possible, recalculated into the Young (rest, equilibrium) contact angle. It was discussed that quartz is not a good model of hydrophilic surface because its contact angle with a gas phase in water is not zero and that a spontaneous attachment between highly hydrophobic materials such as hydrocarbons and Teflon in dynamic system, such as flotation, does not occur.
Źródło:
Physicochemical Problems of Mineral Processing; 2016, 52, 1; 147-154
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of frother type and dose on collectorless flotation of copper-bearing shale in a flotation column
Autorzy:
Kowalczuk, P. B.
Mroczko, D.
Drzymala, J.
Powiązania:
https://bibliotekanauki.pl/articles/109396.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
flotation
hydrophobicity
frother
shale
flotation column
Opis:
In this paper the influence of nonionic (methyl isobutyl carbinol, tri(ethylene glycol) monobutyl ether) and cationic (hexylamine) frothers on flotation of copper-bearing shale in a flotation column was investigated. It was shown that naturally hydrophobic shale did not float in pure water but it floated in the presence of the investigated frothers. The real contact angle of shale, measured by the sessile drop method, was equal to about 40°, while its effective contact angle was zero when shale was floated in a flotation column in pure water. The investigated surfactants increased the effective hydrophobicity of shale from zero to 16±1, 22±1 and 33±2° for coarse, medium and fine particles, respectively. The calculations of the effective contact angle were based on a simplified probabilistic model of flotation.
Źródło:
Physicochemical Problems of Mineral Processing; 2015, 51, 2; 547-558
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Kinetic separation curves based on process rate considerations
Autorzy:
Drzymala, J.
Ratajczak, T.
Kowalczuk, P. B.
Powiązania:
https://bibliotekanauki.pl/articles/110027.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
separation
flotation
kinetics
separation curves
process rate
Opis:
There are many graphical representations of separation results involving time as a crucial parameter determining the kinetics of a process. The graphical representations of results of separation are usually in the form of 2D plots relating two parameters which one of them is time. Time can also be utilized as a complex parameter such as a process rate. The plots involving time are called kinetic curves. Theoretically, the number of kinetic curves is infinite. The basic process kinetic curves, relating either yield (or recovery) and time can be modified to obtain numerous local and global efficiency curves. The global efficiency kinetic curves provide characteristic constants which do not change with the time and yield of a process. In this paper the local and global efficiency plots were created using experimental data which followed the so-called first order kinetics. It was shown that the integral 1st order kinetic equation provided the kinetic constant k which was numerically identical with the 1st order specific rate v, while their units were different (k, 1/min; v, %/(%·min). The global efficiency parameters plotted versus the maximum yield provided another type of plot, which can be called the limits kinetic curve. The limits kinetic curves are very useful for characterizing, quantification and classification of separation systems. The limits kinetic curves can be normalized providing one universal curve with a characteristic point, for instance, v50 indicating the specific rate (or kinetic) constant at the maximum recovery equal to 50%. The mathematical equation of the normalized limits kinetic curve was given in the paper.
Źródło:
Physicochemical Problems of Mineral Processing; 2017, 53, 2; 983-995
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Surface roughness in bubble attachment and flotation of highly hydrophobic solids in presence of frother – experiment and simulations
Autorzy:
Kosior, D.
Kowalczuk, P. B.
Zawala, J.
Powiązania:
https://bibliotekanauki.pl/articles/109319.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
surface roughness
attachment
flotation
kinetics
frother
Opis:
In this paper, the kinetic of the three-phase contact (TPC) formation and the flotation recovery of highly hydrophobic solids with different surface roughness were studied in pure water and aqueous solutions of n-octanol. The surface roughness varied between 1 to 100 μm. It was found that there was a strong influence of surface roughness on both kinetics of TPC formation and flotation. The time of three phase contact formation and flotation rate were much faster for rough surfaces in both water and aqueous solutions of frother. Irrespective of the surface roughness, at above a certain frother dose, the attachment time increased and the flotation rate decreased. It was related to the presence of air at the hydrophobic solid surfaces. The mechanism of this prolongation of the time of TPC formation at the solid surfaces with different roughness due to the frother overdosage was discussed, and the experimental data were confirmed by numerical simulations.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 1; 63-72
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Oil agglomeration of metal-bearing shale in the presence of mixed cationic-anionic surfactants
Autorzy:
Polowczyk, I.
Kruszelnicki, M.
Kowalczuk, P. B.
Powiązania:
https://bibliotekanauki.pl/articles/110617.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
adsorption
zeta potential
synergism
surfactants
kerosene
hydrophobic coagulation
Opis:
This paper reports oil agglomeration of fine metal-bearing shale particles in the presence of cationic (dodecylamine hydrochloride) and anionic (sodium dodecyl sulfate) surfactants and their mixture. The experimental results demonstrated that there was a strong relationship between zeta potential, hydrophobic coagulation, oil agglomeration and particle hydrophobicity in the presence of cationic surfactant, whereas shale neither coagulated nor agglomerated in the presence of anionic surfactant. Addition of either anionic or cationic surfactant in emulsification of a bridging oil increased the size of agglomerates and reduced the concentration of surfactant used in the suspension. The results pointed to synergism between cationic and anionic surfactants in oil agglomeration. Based on the results obtained from this study, the mechanism of oil agglomeration of shale in the presence of ionic surfactants and their mixture was elucidated.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 4; 1052-1059
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Validation of empirical and semi-analytical remote sensing algorithms for estimating absorption by Coloured Dissolved Organic Matter in the Baltic Sea from SeaWiFS and MODIS imagery
Autorzy:
Kowalczuk, P.
Darecki, M.
Zablocka, M.
Gorecka, I.
Powiązania:
https://bibliotekanauki.pl/articles/47876.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
validation
remote sensing
Ocean colour
satellite validation
coloured dissolved organic matter
organic matter
absorption
Baltic Sea
Gdansk Gulf
Vistula River
Opis:
An extensive bio-optical data set obtained from field measurements was used to evaluate the performance of an empirical (Kowalczuk et al. 2005) and two semi- analytical algorithms: Carder et al. (1999) and GSM01 (Maritorena et al. 2002) for estimating CDOM absorption in the Baltic Sea. The data set includes coincident measurements of radiometric quantities and absorption coefficients of CDOM made during 43 cruises between 2000 and 2008. In the first stage of the analysis, the accuracy of the empirical algorithm by Kowalczuk et al. (2005) was assessed using in situ measurements of remote sensing reflectance. Validation results improved when matching points located in Gulf of Gdańsk close to the Vistula River mouth were eliminated from the data set. The calculated errors in the estimation of aCDOM(400) in the first phase of the analysis were Bias = −0.02, RMSE = 0.46 and R2 = 0.70. In the second stage, the empirical algorithm was tested on satellite data from SeaWiFS and MODIS imagery. The satellite data were corrected atmospherically with the MUMM algorithm designed for turbid coastal and inland waters and implemented in the SeaDAS software. The results of the best case scenario for estimating the CDOM absorption coefficient aCDOM(400), based on SeaWiFS data, were Bias = −0.02, RMSE = 0.23 and R2 = 0.40. The validation of the Kowalczuk et al. (2005) empirical algorithm applied to MODIS data led to a less accurate estimate of aCDOM(400): Bias = −0.03, RMSE = 0.19 and R2 = 0.29. This assessment of the accuracy of standard semi-analytical algorithms available in the SeaWiFS and MODIS imagery processing software revealed that both algorithms (GSM 01 and Carder) underestimate CDOM absorption in the Baltic Sea with mean systematic and random errors in excess of 70%. The paper presents examples of the application of the Kowalczuk et al. (2005) empirical algorithm for producing maps of the seasonal distribution of aCDOM(400) in the Baltic Sea between 2004 and 2008.
Źródło:
Oceanologia; 2010, 52, 2; 171-196
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structure and surface energy of both fluorite halves after cleaving along selected crystallographic planes
Autorzy:
Janicki, M. J.
Drzymala, J.
Kowalczuk, P. B.
Powiązania:
https://bibliotekanauki.pl/articles/110167.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fluorite
fluoride
surface energy
interfacial energy
cleaving
reorganization
surface ions
Opis:
The density functional theory, supported with a commercial software, was used to compute the geometry and surface energy of fluorite cleaved along the (111), (110) and (100) planes. In the case of cleaving a piece of fluorite along the (111) plane the two newly created surfaces are identical consisting of fluorite ions with the surface energy equal to 0.384 J/m2. Cleaving fluorite along the (110) plane also provides identical halves and, both contain one Ca ion next to two F ions, with the surface energy equal to 0.723 J/m2. When cleaving takes place along the (100) plane, it creates two corresponding halves with different surface structures. One half, having only surface Ca ions (100Ca) has the surface energy equal to 0.866 J/m2, while the surface energy of the second half, having only F surface ions (100F), is 0.458 J/m2. Different structures and energies of the corresponding fluorite surfaces, that is (100Ca) and (100F) planes, should have an impact on their chemical properties, including hydrophobicity expressed by contact angle. The calculations performed in the paper also showed that reorganization of fluorite surfaces after cleaving was insignificant for all of the investigated planes.
Źródło:
Physicochemical Problems of Mineral Processing; 2016, 52, 1; 451-458
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fluorescence measured in situ as a proxy of CDOM absorption and DOC concentration in the Baltic Sea
Autorzy:
Kowalczuk, P.
Zablocka, M.
Sagan, S.
Kulinski, K.
Powiązania:
https://bibliotekanauki.pl/articles/48318.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
Baltic Sea
measurement
optical property
dissolved organic carbon
concentration
dissolved organic matter
fluorescence
global climate model
validation
Źródło:
Oceanologia; 2010, 52, 3; 431-471
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
In search of an efficient frother for pre-flotation of carbonaceous shale from the kupferschiefer stratiform copper ore
Autorzy:
Kowalczuk, P. B.
Buluc, B.
Sahbaz, O.
Drzymala, J.
Powiązania:
https://bibliotekanauki.pl/articles/109705.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
frother
pre-flotation
copper ore
shale
Opis:
This papers shows that frothers such as aliphatic alcohols (CnH2n+1OH), poly(propylene glycols) (HO(C3H6O)mH), poly(propylene glycol) alkyl ethers (CnH2n+1O(C3H6O)mH) and poly(ethylene glycol) alkyl ethers (CnH2n+1O(C2H4O)mH), can be used for collectorless flotation of a sample of carbonaceous copper shale manually separated from the Kupferschiefer stratiform copper ore. It was shown that flotation is influenced by the type and dose of frothers. The best flotation results were obtained with tri(propylene glycol) butyl ether C4P3, tri(propylene glycol) propyl ether C3P3 and tri(propylene glycol) P3. For these frothers, the yield vs. frother dose relationship was in the form of convex curves indicating that carbonaceous copper shale can float at relatively low dosages of the frother. It means that these frothers can be used for pre-flotation of carbonaceous matter from the investigated copper ore. Other frothers formed concave yield–frother dose relationships and were less effective.
Źródło:
Physicochemical Problems of Mineral Processing; 2014, 50, 2; 835-840
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Water contact angle on corresponding surfaces of freshly fractured fluorite, calcite and mica
Autorzy:
Kowalczuk, P. B.
Akkaya, C.
Ergun, M.
Janicki, M.
Sahbaz, O.
Drzymala, J.
Powiązania:
https://bibliotekanauki.pl/articles/110595.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
contact angle
surface properties
cleaving plane
surface composition
corresponding halves
fluorite
calcite
mica
Opis:
Advancing and receding contact angles of water with corresponding surfaces of freshly fractured calcite, fluorite and mica were measured. The corresponding surfaces were obtained by mechanical splitting of a small lump of each mineral into two pieces. Theoretical considerations revealed that depending on the mineral cleaving plane, surfaces created by splitting into halves can be either identical or entirely different as far as their surface chemical composition is concerned. It was experimentally established that receding and advancing contact angles measured on the corresponding surfaces of fluorite, calcite and mica were identical for the sessile drop method. When the contact angle was measured by the captive bubble approach, there were small differences in the contact angles measured on the corresponding surfaces of fluorite. It was most probably due to surface irregularities and roughness, and therefore different times needed to rupture the liquid film between the bubble and solid surface.
Źródło:
Physicochemical Problems of Mineral Processing; 2017, 53, 1; 192-201
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Two models for absorption by coloured dissolved organic matter (CDOM)
Autorzy:
Schwarz, J.N.
Kowalczuk, P.
Kaczmarek, S.
Cota, G.F.
Mitchell, B.G.
Kahru, M.
Chavez, F.P.
Cunningham, A.
McKee, D.
Gege, P.
Kishino, M.
Phinney, D.A.
Raine, R.
Powiązania:
https://bibliotekanauki.pl/articles/47774.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
ocean colour
coloured dissolved organic matter
surface water
coastal water
spectrophotometric measurement
ultraviolet absorption
absorption
Vistula River
Opis:
The standard exponential model for CDOM absorption has been applied to data from diverse waters. Absorption at 440 nm (ag440) ranged between close to zero and 10 m−1, and the slope oft he semilogarithmic absorption spectrum over a minimum range of400 to 440 nm (s440) ranged between <0.01 and 0.04 nm−1. No relationship was found between ag440 or s440 and salinity. Except in the southern Baltic, s440 was found to have a broad distribution (0.0165 ± 0.0035), suggesting that it should be introduced as an additional variable in bio-optical models when ag440 is large. An alternative model for CDOM absorption was applied to available high quality UV-visible absorption spectra from the WisGla river (Poland). This model assumes that the CDOM absorption spectrum comprises distinct Gaussian absorption bands in the UV, similar to those ofb enzene. Five bands were fit to the data. The mean central energy ofal l bands was higher in early summer (E ∼7.2, 6.6, 6.4, 6.2 and 5.5 eV or 172, 188, 194, 200 and 226 nm) than in winter. The higher energy bands were found to decay in both height and width with increasing salinity, while lower energy bands broadened with increasing salinity. s440 was found to be correlated with shape parameters of the bands centred at 6.4 and 5.5 eV. While the exponential model is convenient for optical modelling and remote sensing applications, these results suggest that the Gaussian model offers a deeper understanding ofc hemical interactions affecting CDOM molecular structure.
Źródło:
Oceanologia; 2002, 44, 2
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A study of episodic events in the Baltic Sea – combined in situ and satellite observations
Autorzy:
Lysiak-Pastuszak, E.
Bartoszewicz, M.
Bradtke, K.
Darecki, M.
Drgas, N.
Kowalczuk, P.
Krasniewski, W.
Krezel, A.
Krzyminski, W.
Lewandowski, L.
Mazur-Marzec, H.
Piliczewski, B.
Sagan, S.
Sutryk, K.
Witek, B.
Powiązania:
https://bibliotekanauki.pl/articles/48563.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
Baltic Sea
Ferry Box project
algal bloom
hepatotoxin
satellite image
coastal water
oceanic water
salinity
temperature
Opis:
A project was developed concerning the operational system of surveillance and the recording of episodic events in the Baltic Sea. In situ information was to be combined with multi-sensory satellite imagery to determine the extent of algal blooms, to track their evolution and that of rapid environmental events like hydrological fronts. The main element of the system was an autonomous Ferry Box module on a ferry operating between Gdynia and Karlskrona, automatically measuring temperature, salinity and chlorophyll a fluorescence. At pre-selected locations, discrete water samples were collected, which were subsequently analysed for their phytoplankton content, and algal hepato- and neurotoxins; they were also used in toxicity tests with Artemia franciscana.
Źródło:
Oceanologia; 2012, 54, 2
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simple stable discrete-time generalised predictive control with anticipated filtration of control error
Autorzy:
Kowalczuk, Z.
Suchomski, P.
Powiązania:
https://bibliotekanauki.pl/articles/206013.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
sterowanie predykcyjne
synteza systemu sterowania
system dyskretno-czasowy
discrete-time systems
non-minimal systems
predictive control
system design
Opis:
It is shown that under some specific conditions, the solution of the generalised predictive control (GPC) design using the concept of anticipated filtering (AF) of the control error always exists, and that such a design leads to stable control systems with definite closed-loop characteristics. The plant cancellation issue is taken into account, and it is demonstrated that certain bounds on GPC design parameters have to be considered. An iterative procedure for simultaneous determination of the three basic design-tuning parameters: the control horizon, the controller gain, and the order of plant cancellation, is also supplied. An important feature of this approach is that the anticipated filtering makes it possible to reduce a disagreeable control effort associated with GPC and to make the [lambda]-tuning mechanism practicable. The bounds on the GPC design parameters are discussed, and certain optimal tuning rules are proposed and validated via simulated experiments.
Źródło:
Control and Cybernetics; 2002, 31, 1; 17-41
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł

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