The dye-sensitized solar cells microfluidically integrated with a redox flow battery (µDSSC-RFB) ... more The dye-sensitized solar cells microfluidically integrated with a redox flow battery (µDSSC-RFB) belong to a new emerging class of green energy sources with an inherent opportunity for energy storage. The successful engineering of microfluidically linked systems is, however, a challenging subject, as the hydrodynamics of electrolyte flow influences the electron and species transport in the system in several ways. In the article, we have analyzed the microflows hydrodynamics by means of the lattice-Boltzmann method, using the algebraic solution of the Navier-Stokes equation for a duct flow and experimentally by the micro particle image velocimetry method. Several prototypes of µDSSC were prepared and tested under different flow conditions. The efficiency of serpentine µDSSC raised from 2.8% for stationary conditions to 3.1% for electrolyte flow above 20 mL/h, while the fill factor increased about 13% and open-circuit voltage from an initial 0.715 V to 0.745 V. Although the hexagonal ...
Mikroaparaty (mikromieszalniki, mikroseparatory, mikroreaktory, mikro wymienniki ciepła itp.) są ... more Mikroaparaty (mikromieszalniki, mikroseparatory, mikroreaktory, mikro wymienniki ciepła itp.) są podstawowymi elementami systemów LOC (Lab On a Chip) – miniaturowych odpowiedników instalacji procesowych. Przejście ze skali makro do skali mikro i nano w projektowaniu procesów i aparatów nie jest jednak stricte zagadnieniem z dziedziny powiększania skali, z racji odmiennych metod wytwarzania mikroaparatów oraz sposobów realizacji procesów jednostkowych w mikrosystemach. Projektowanie procesowe i aparaturowe na początku 21. wieku osiągnęło poziom pozwalający sprawnie i efektywnie rozwiązywać problemy związane z symulacjami, projektowaniem, kontrolą, diagnostyką, planowaniem i optymalizacją wielkoskalowych ciągłych i okresowych instalacji przemysłowych. Z racji przesunięcia się środka ciężkości w dziedzinie nowych technologii ze skali metrów do skali milimetrów a nawet nanometrów, koniecznością staje się rozszerzenie metod i algorytmów na nowe obszary aplikacji – instalacje procesowe na...
Przepływy w mikrokanałach układów lab on a chip (LOC) mogą być spontaniczne, w wyniku oddziaływań... more Przepływy w mikrokanałach układów lab on a chip (LOC) mogą być spontaniczne, w wyniku oddziaływań powierzchniowych, sił Coulomba lub wywołane gradientem ciśnienia. Stosunek powierzchni do objętości wzrasta dziesięciokrotnie z dziesięciokrotną redukcją wymiaru geometrycznego systemu, co jest kluczowym efektem, koniecznym do uwzględnienia przy projektowaniu mikroaparatów. Efekty powierzchniowe, jak również struktura powierzchni kanału wywierają dominujący wpływ na charakterystykę przepływu płynu w mikrokanałach. Przepływy laminarne cieczy newtonowskich w prostoliniowych kanałach o gładkich ścianach i średnicy w zakresie 1÷1000 μm spełniają warunek ciągłości, jako że wymiar charakterystyczny w tym przypadku jest kilka rzędów większy niż średnia droga swobodna cząsteczki – Kn < 0,001, a co za tym idzie w sposób prawidłowy są opisywane przez równanie Naviera-Stokesa. Dla przepływu gazów założenie ciągłości strugi nie zawsze jest spełnione dla mikroprzepływów, zwłaszcza w przypadku prz...
We describe a high-performance implementation of the lattice Boltzmann method (LBM) for sparse 3D... more We describe a high-performance implementation of the lattice Boltzmann method (LBM) for sparse 3D geometries on graphic processors (GPU). The main contribution of this work is a data layout that allows to minimise the number of redundant memory transactions during the propagation step of LBM. We show that by using a uniform mesh of small three-dimensional tiles and a careful data placement it is possible to utilise more than 70% of maximum theoretical GPU memory bandwidth for D3Q19 lattice and double precision numbers. The performance of our implementation is thoroughly examined and compared with other GPU implementations of LBM. The proposed method performs the best for sparse geometries with good spatial locality.
In this study, we thoroughly analyzed molecular gradient generation, its stability over time, and... more In this study, we thoroughly analyzed molecular gradient generation, its stability over time, and linearity in our high-throughput drug screening microfluidic assay (HTS). These parameters greatly affect the precision and accuracy of the device’s analytical protocol. As part of the research, we developed a mathematical model of dependence of the concentration profile on the initial concentrations of active substances in reservoirs and the number of tilts, as well as the dependence of the active substance concentration profiles in the culture chambers on the concentration profile of the reference dye in the indicator chamber. The mean concentration prediction error of the proposed equations ranged from 1.4% to 2.4% for the optimized parameters of the procedure and did not increase with the incubation time. The concentration profile linearity index, Pearson’s correlation coefficient reached −0.997 for 25 device tilts. The observed time stability of the profiles was very good. The mean...
The aim of our research was to develop a numerical model of microflows occurring in the culture c... more The aim of our research was to develop a numerical model of microflows occurring in the culture chambers (CC) of a microfluidic device of our construction for high-throughput drug screening. The incompressible fluid flow model is based on the lattice-Boltzmann equation, with an external body force term approximated by the He-Shan-Doolen scheme and the Bhatnagar-Gross-Krook approximation of the collision operator. The model accuracy was validated by the algebraic solution of the Navier–Stokes equation (NSE) for a fully developed duct flow, as well as experimentally. The mean velocity prediction error for the middle-length cross-section of CC was 1.0%, comparing to the NSE algebraic solution. The mean error of volumetric flow rate prediction was 6.1%, comparing to the experimental results. The analysis of flow hydrodynamics showed that the discrepancies from the plug-flow-like velocity profile are observed close to the inlets only, and do not influence cell cultures in the working are...
To study the simultaneous effect of the molecular gradient of polyphenols (curcumin, trans-resver... more To study the simultaneous effect of the molecular gradient of polyphenols (curcumin, trans-resveratrol, and wogonin) and biological factors released from tumor cells on apoptosis of adjacent cells, a novel microfluidic system was designed and manufactured. The small height/volume of microfluidic culture chambers and static conditions allowed for establishing the local microenvironment and maintaining undisturbed concentration profiles of naturally secreted from cells biochemical factors. In all trials, we observe that these conditions significantly affect cell viability by stimulating cell apoptosis at lower concentrations of polyphenols than in traditional multiwell cultures. The observed difference varied between 20.4–87.8% for curcumin, 11.0–37.5% for resveratrol, and 21.7–62.2% for wogonin. At low concentrations of polyphenols, the proapoptotic substances released from adjacent cells, like protein degradation products, significantly influence cell viability. The mean increase in...
ABSTRACT Batch sorption experiments were carried out for the removal of cationic dyes (methylene ... more ABSTRACT Batch sorption experiments were carried out for the removal of cationic dyes (methylene blue and malachite green) from their aqueous solutions using sorbent made from fly ash-a waste material. Effects of various experimental parameters: initial dye concentration, contact time, pH, adsorbent dosage, solution temperature, surfactant addition and ionic strength on the fly ash sorption of dyes were evaluated. The isothermal data for sorption followed the Langmuir model. The maximum sorption capacity obtained for methylene blue and malachite green was 36.05 mg/g and 40.65 mg/g, respectively. Kinetic studies indicate that sorption on fly ash follows the pseudo-second order kinetics. Present research suggests that fly ash could be an appropriate adsorbent for the removal of basic dyes from aqueous solutions.
In the paper, results of investigations of the drying of microspherical capillary-porous particle... more In the paper, results of investigations of the drying of microspherical capillary-porous particles are presented. Experiments were carried out in a spouted bed wryer with a draft tube. Kinetics of drying of the investigated material was determined. The falling drying rate period is described using Fick's diffusion equation. In this paper, results obtained from the analytical solution of the model are compared with a numerical solution as well as with classic equation and with experimental data.
In the paper there are presented modem computer aided engineering techniques and conception of ap... more In the paper there are presented modem computer aided engineering techniques and conception of application of computer techniques in integrated design process in chemical engineering. There is also discussed present stage of development of CFD techniques applied to multiphase systems modelling.
Experimental investigations of liquid velocity distributions and power input in a jet-loop reacto... more Experimental investigations of liquid velocity distributions and power input in a jet-loop reactor have been carried out on a semi-industrial scale. The effect of solids concentrations on the liquid velocity distributions and the power input in the reactor is determined. It was found that solids reduce liquid flow velocity along the draft tube by 30%. Profiles of liquid velocity are flattened due to the presence of solids but dependent on the particle size. This effect increases with the decrease of the particle diameter and with the increase of the liquid flow rate. Radial velocity profiles are described by Schlichting's correlation. Power input is found to increase slightly with the solids concentration.
Removal of cationic dyes, rhodamine B and methylene blue, from aqueous solutions by unmodified be... more Removal of cationic dyes, rhodamine B and methylene blue, from aqueous solutions by unmodified beech sawdust was investigated. The adsorption kinetics and equilibrium data were fitted by various models. The pseudosecond order kinetics and the Langmuir model described biosorption data reasonably well. The maximum adsorption capacity was 70.40 mg.dm(-3) and 52.66 mg.dm(-3) for rhodamine B and methylene blue, respectively. The study shows that beech sawdust has the potential off application as an efficient sorbent for removal of cationic dyes.
Economic and techn. aspects of the sepn. of CO2 from synthesis gas for energy prodn. in integrate... more Economic and techn. aspects of the sepn. of CO2 from synthesis gas for energy prodn. in integrated gasification combined cycle and by underground coal gasification were taken into consideration. A new concept for simultaneous sepn. of CO2, S compds. and moisture from the fuel gas (prior to combustion) by a membrane process was outlined. Selective sepn. of acid gas components in the membrane contactor resulted in redn. of plant size and improving the CO2 stream quality necessary for its sequestration in a single-stage system.
The aim of this work was to determine the efficiency of the hybrid membrane-sorption system for t... more The aim of this work was to determine the efficiency of the hybrid membrane-sorption system for the removal of heavy metal ions (Cr(3+) being the case in point) from model aqueous solutions. It has been demonstrated that this type of reactor enables the adsorption process to be combined with a separation process involving capillary membranes submerged in the solution being treated. When operated under conditions below the critical flux of the permeate, the submerged membrane system provides high removal efficiency at low energy demand. The experiments were aimed at evaluating the influence of aeration rate, transmembrane pressure and sorbent concentration on the efficiency of Cr(III) ion removal from aqueous solutions. The use of peanut shells, a low-cost waste biosorbent, was proposed as an alternative to conventional carbon adsorbents. Owing to the very low operating costs involved, the treatment mode described above may become competitive with the classical methods of water and w...
Eleven waste bio-materials were used as biosorbents for removal of Cu2+ and Cr3+ ions from aq. so... more Eleven waste bio-materials were used as biosorbents for removal of Cu2+ and Cr3+ ions from aq. solns. Sorption equil. and kinetic consts. were detd. at 20-60 degrees C and pH 3-5. The sorption capacity was 20-60 mg/g not lower than that for a polymeric sorbent with carboxylic groups and an activated C.
Pseudomonas aeruginosa bacteria was sepd. from the rhamnolipid-contg. fermentation broth by ultra... more Pseudomonas aeruginosa bacteria was sepd. from the rhamnolipid-contg. fermentation broth by ultrafiltration through a com. polysulfone membrane (cut-off 100 kDa) under cross-flow mode conditions (up to 2 bar). At the bacteria concn. 2 g/L, the flux of the suspension 100 L/m(2)h was achieved.
The dye-sensitized solar cells microfluidically integrated with a redox flow battery (µDSSC-RFB) ... more The dye-sensitized solar cells microfluidically integrated with a redox flow battery (µDSSC-RFB) belong to a new emerging class of green energy sources with an inherent opportunity for energy storage. The successful engineering of microfluidically linked systems is, however, a challenging subject, as the hydrodynamics of electrolyte flow influences the electron and species transport in the system in several ways. In the article, we have analyzed the microflows hydrodynamics by means of the lattice-Boltzmann method, using the algebraic solution of the Navier-Stokes equation for a duct flow and experimentally by the micro particle image velocimetry method. Several prototypes of µDSSC were prepared and tested under different flow conditions. The efficiency of serpentine µDSSC raised from 2.8% for stationary conditions to 3.1% for electrolyte flow above 20 mL/h, while the fill factor increased about 13% and open-circuit voltage from an initial 0.715 V to 0.745 V. Although the hexagonal ...
Mikroaparaty (mikromieszalniki, mikroseparatory, mikroreaktory, mikro wymienniki ciepła itp.) są ... more Mikroaparaty (mikromieszalniki, mikroseparatory, mikroreaktory, mikro wymienniki ciepła itp.) są podstawowymi elementami systemów LOC (Lab On a Chip) – miniaturowych odpowiedników instalacji procesowych. Przejście ze skali makro do skali mikro i nano w projektowaniu procesów i aparatów nie jest jednak stricte zagadnieniem z dziedziny powiększania skali, z racji odmiennych metod wytwarzania mikroaparatów oraz sposobów realizacji procesów jednostkowych w mikrosystemach. Projektowanie procesowe i aparaturowe na początku 21. wieku osiągnęło poziom pozwalający sprawnie i efektywnie rozwiązywać problemy związane z symulacjami, projektowaniem, kontrolą, diagnostyką, planowaniem i optymalizacją wielkoskalowych ciągłych i okresowych instalacji przemysłowych. Z racji przesunięcia się środka ciężkości w dziedzinie nowych technologii ze skali metrów do skali milimetrów a nawet nanometrów, koniecznością staje się rozszerzenie metod i algorytmów na nowe obszary aplikacji – instalacje procesowe na...
Przepływy w mikrokanałach układów lab on a chip (LOC) mogą być spontaniczne, w wyniku oddziaływań... more Przepływy w mikrokanałach układów lab on a chip (LOC) mogą być spontaniczne, w wyniku oddziaływań powierzchniowych, sił Coulomba lub wywołane gradientem ciśnienia. Stosunek powierzchni do objętości wzrasta dziesięciokrotnie z dziesięciokrotną redukcją wymiaru geometrycznego systemu, co jest kluczowym efektem, koniecznym do uwzględnienia przy projektowaniu mikroaparatów. Efekty powierzchniowe, jak również struktura powierzchni kanału wywierają dominujący wpływ na charakterystykę przepływu płynu w mikrokanałach. Przepływy laminarne cieczy newtonowskich w prostoliniowych kanałach o gładkich ścianach i średnicy w zakresie 1÷1000 μm spełniają warunek ciągłości, jako że wymiar charakterystyczny w tym przypadku jest kilka rzędów większy niż średnia droga swobodna cząsteczki – Kn < 0,001, a co za tym idzie w sposób prawidłowy są opisywane przez równanie Naviera-Stokesa. Dla przepływu gazów założenie ciągłości strugi nie zawsze jest spełnione dla mikroprzepływów, zwłaszcza w przypadku prz...
We describe a high-performance implementation of the lattice Boltzmann method (LBM) for sparse 3D... more We describe a high-performance implementation of the lattice Boltzmann method (LBM) for sparse 3D geometries on graphic processors (GPU). The main contribution of this work is a data layout that allows to minimise the number of redundant memory transactions during the propagation step of LBM. We show that by using a uniform mesh of small three-dimensional tiles and a careful data placement it is possible to utilise more than 70% of maximum theoretical GPU memory bandwidth for D3Q19 lattice and double precision numbers. The performance of our implementation is thoroughly examined and compared with other GPU implementations of LBM. The proposed method performs the best for sparse geometries with good spatial locality.
In this study, we thoroughly analyzed molecular gradient generation, its stability over time, and... more In this study, we thoroughly analyzed molecular gradient generation, its stability over time, and linearity in our high-throughput drug screening microfluidic assay (HTS). These parameters greatly affect the precision and accuracy of the device’s analytical protocol. As part of the research, we developed a mathematical model of dependence of the concentration profile on the initial concentrations of active substances in reservoirs and the number of tilts, as well as the dependence of the active substance concentration profiles in the culture chambers on the concentration profile of the reference dye in the indicator chamber. The mean concentration prediction error of the proposed equations ranged from 1.4% to 2.4% for the optimized parameters of the procedure and did not increase with the incubation time. The concentration profile linearity index, Pearson’s correlation coefficient reached −0.997 for 25 device tilts. The observed time stability of the profiles was very good. The mean...
The aim of our research was to develop a numerical model of microflows occurring in the culture c... more The aim of our research was to develop a numerical model of microflows occurring in the culture chambers (CC) of a microfluidic device of our construction for high-throughput drug screening. The incompressible fluid flow model is based on the lattice-Boltzmann equation, with an external body force term approximated by the He-Shan-Doolen scheme and the Bhatnagar-Gross-Krook approximation of the collision operator. The model accuracy was validated by the algebraic solution of the Navier–Stokes equation (NSE) for a fully developed duct flow, as well as experimentally. The mean velocity prediction error for the middle-length cross-section of CC was 1.0%, comparing to the NSE algebraic solution. The mean error of volumetric flow rate prediction was 6.1%, comparing to the experimental results. The analysis of flow hydrodynamics showed that the discrepancies from the plug-flow-like velocity profile are observed close to the inlets only, and do not influence cell cultures in the working are...
To study the simultaneous effect of the molecular gradient of polyphenols (curcumin, trans-resver... more To study the simultaneous effect of the molecular gradient of polyphenols (curcumin, trans-resveratrol, and wogonin) and biological factors released from tumor cells on apoptosis of adjacent cells, a novel microfluidic system was designed and manufactured. The small height/volume of microfluidic culture chambers and static conditions allowed for establishing the local microenvironment and maintaining undisturbed concentration profiles of naturally secreted from cells biochemical factors. In all trials, we observe that these conditions significantly affect cell viability by stimulating cell apoptosis at lower concentrations of polyphenols than in traditional multiwell cultures. The observed difference varied between 20.4–87.8% for curcumin, 11.0–37.5% for resveratrol, and 21.7–62.2% for wogonin. At low concentrations of polyphenols, the proapoptotic substances released from adjacent cells, like protein degradation products, significantly influence cell viability. The mean increase in...
ABSTRACT Batch sorption experiments were carried out for the removal of cationic dyes (methylene ... more ABSTRACT Batch sorption experiments were carried out for the removal of cationic dyes (methylene blue and malachite green) from their aqueous solutions using sorbent made from fly ash-a waste material. Effects of various experimental parameters: initial dye concentration, contact time, pH, adsorbent dosage, solution temperature, surfactant addition and ionic strength on the fly ash sorption of dyes were evaluated. The isothermal data for sorption followed the Langmuir model. The maximum sorption capacity obtained for methylene blue and malachite green was 36.05 mg/g and 40.65 mg/g, respectively. Kinetic studies indicate that sorption on fly ash follows the pseudo-second order kinetics. Present research suggests that fly ash could be an appropriate adsorbent for the removal of basic dyes from aqueous solutions.
In the paper, results of investigations of the drying of microspherical capillary-porous particle... more In the paper, results of investigations of the drying of microspherical capillary-porous particles are presented. Experiments were carried out in a spouted bed wryer with a draft tube. Kinetics of drying of the investigated material was determined. The falling drying rate period is described using Fick's diffusion equation. In this paper, results obtained from the analytical solution of the model are compared with a numerical solution as well as with classic equation and with experimental data.
In the paper there are presented modem computer aided engineering techniques and conception of ap... more In the paper there are presented modem computer aided engineering techniques and conception of application of computer techniques in integrated design process in chemical engineering. There is also discussed present stage of development of CFD techniques applied to multiphase systems modelling.
Experimental investigations of liquid velocity distributions and power input in a jet-loop reacto... more Experimental investigations of liquid velocity distributions and power input in a jet-loop reactor have been carried out on a semi-industrial scale. The effect of solids concentrations on the liquid velocity distributions and the power input in the reactor is determined. It was found that solids reduce liquid flow velocity along the draft tube by 30%. Profiles of liquid velocity are flattened due to the presence of solids but dependent on the particle size. This effect increases with the decrease of the particle diameter and with the increase of the liquid flow rate. Radial velocity profiles are described by Schlichting's correlation. Power input is found to increase slightly with the solids concentration.
Removal of cationic dyes, rhodamine B and methylene blue, from aqueous solutions by unmodified be... more Removal of cationic dyes, rhodamine B and methylene blue, from aqueous solutions by unmodified beech sawdust was investigated. The adsorption kinetics and equilibrium data were fitted by various models. The pseudosecond order kinetics and the Langmuir model described biosorption data reasonably well. The maximum adsorption capacity was 70.40 mg.dm(-3) and 52.66 mg.dm(-3) for rhodamine B and methylene blue, respectively. The study shows that beech sawdust has the potential off application as an efficient sorbent for removal of cationic dyes.
Economic and techn. aspects of the sepn. of CO2 from synthesis gas for energy prodn. in integrate... more Economic and techn. aspects of the sepn. of CO2 from synthesis gas for energy prodn. in integrated gasification combined cycle and by underground coal gasification were taken into consideration. A new concept for simultaneous sepn. of CO2, S compds. and moisture from the fuel gas (prior to combustion) by a membrane process was outlined. Selective sepn. of acid gas components in the membrane contactor resulted in redn. of plant size and improving the CO2 stream quality necessary for its sequestration in a single-stage system.
The aim of this work was to determine the efficiency of the hybrid membrane-sorption system for t... more The aim of this work was to determine the efficiency of the hybrid membrane-sorption system for the removal of heavy metal ions (Cr(3+) being the case in point) from model aqueous solutions. It has been demonstrated that this type of reactor enables the adsorption process to be combined with a separation process involving capillary membranes submerged in the solution being treated. When operated under conditions below the critical flux of the permeate, the submerged membrane system provides high removal efficiency at low energy demand. The experiments were aimed at evaluating the influence of aeration rate, transmembrane pressure and sorbent concentration on the efficiency of Cr(III) ion removal from aqueous solutions. The use of peanut shells, a low-cost waste biosorbent, was proposed as an alternative to conventional carbon adsorbents. Owing to the very low operating costs involved, the treatment mode described above may become competitive with the classical methods of water and w...
Eleven waste bio-materials were used as biosorbents for removal of Cu2+ and Cr3+ ions from aq. so... more Eleven waste bio-materials were used as biosorbents for removal of Cu2+ and Cr3+ ions from aq. solns. Sorption equil. and kinetic consts. were detd. at 20-60 degrees C and pH 3-5. The sorption capacity was 20-60 mg/g not lower than that for a polymeric sorbent with carboxylic groups and an activated C.
Pseudomonas aeruginosa bacteria was sepd. from the rhamnolipid-contg. fermentation broth by ultra... more Pseudomonas aeruginosa bacteria was sepd. from the rhamnolipid-contg. fermentation broth by ultrafiltration through a com. polysulfone membrane (cut-off 100 kDa) under cross-flow mode conditions (up to 2 bar). At the bacteria concn. 2 g/L, the flux of the suspension 100 L/m(2)h was achieved.
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