Wyniki wyszukiwania - Biblioteka Nauki

1

The relative motion of membranes

100%

Roberts M.

Open Physics

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2010

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tom 8

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nr 6

915-919

EN

The relative classical motion of membranes is governed by the equation (w β cα c r βa)a = R δγβα r gb x δa p aγ, where w is the hessian. This is a generalization of the geodesic deviation equation and can be derived from the lagrangian p · ṙ. Quantum mechanically the picture is less clear. Some quantizations of the classical equations are attempted so that the question as to whether the Universe started with a quantum fluctuation can be addressed.

2

Membrany w naszym życiu

100%

Wyrzyk M.

LAB Laboratoria, Aparatura, Badania

|

2009

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tom R. 14, nr 5/6

26-27

3

Modelling and transport in liquid membrane contactors

100%

Coelhoso I. M. , Crespo J. G.

Environment Protection Engineering

|

1999

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tom Vol. 25, nr 1-2

21-28

EN

The paper deals with carrier-facilitated transport of organic acids and aminoacids in supported liquid membranes. The hydrophobic polypropylene membranes in hollow fibre module were applied in the research. The knowledge about transport mechanism is essential for process optimisation. The quaternary ammonium salt TOMAC was a carrier, which transported lactate from aqueous feed phase to aqueous stripping phase that was diluted sulphuric acid. The accompanying counterbalanced transport of anionic species took place in opposite direction. The mathematical model of coupled transport was presented. The effect of osmotic pressure, hydrophobic and electrostatic effects were taken into account. The equilibrium of reversible reaction between carrier and solute was determined taking into account effect of coupled transport of anionic species in opposite direction. The separation of aminoacids, e.g. phenylalanine and tryptophan, with reversed micelle in TOMAC/hexanol/n-heptane system was very effective. This model of mass transport was analysed by taking into account two approaches, i.e. constant and variable partitions. The following resistance to mass transport were assumed in the model, e.g. boundary layer in the liquid phase inside the hollow fiber, resistance to solute diffusion inside the pores filled with liquid phase (membrane), boundary layer in shell side of the tubes. The main aim of the work was detailed understanding of interactions between carrier and solute across liquid membrane. The second aim was to determine hydrophobic and electrostatic effects during the solute transport through structured liquids (reversed micelles). Analysis of the mathematical model of solute transport showed an important role of solute partition in results of simulation. The proposed model makes it possible to involve variation of partition coefficient that is not possible in commonly used classical methods.

4

Separacja gazów kopalnianych w membranach kapilarnych z poli(4-metylopentenu-1)

100%

Kulawski J. , Białecka B. , Pilch-Kowalczyk A. , Rejman-Burzyńska A.

Inżynieria Chemiczna i Procesowa

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1999

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tom T. 20, z. 4

465-484

PL

Opisano wpływ parametrów procesu na przebieg i efektywność separacji gazów kopalnianych średnio- i niskometanowych. Proces prowadzono w układzie współ- i przeciwprądu, z zastosowaniem nadciśnienia po stronie zasilania oraz odpływu swobodnego albo próżni po stronie permeatu. Obliczono współczynniki permeacji poszczególnych gazów w mieszaninie oraz współczynniki selektywności separacji. Opracowano prosty model obliczania przewidywanego składu permeatu dla określonego gazu surowego i założonych warunków procesu. Model ten daje dobrą zgodność z wynikami eksperymentu.

EN

The effect of operating parameters on the performance of separation of gases of medium and small methane content was described. The process has been carried out in cocurrent- and countercurrent gas flow at a pressure applied on the feed side and vacuum on the permeate side. The permeability coefficients for each gas component were calculated. Simple model for the prediction of permeate composition has been elaborated. It remained in good agreement with the experimental results.

5

Badanie właściwości filtracyjnych i mechanicznych polipropylenowych membran kapilarnych

80%

Doliński M. , Szwast M. , Fabianowski W. , Piątkiewicz W.

Inżynieria i Aparatura Chemiczna

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2009

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tom Nr 5

22-23

PL

Konieczność ochrony środowiska oraz względy ekonomiczne kierują prace wielu badaczy w kierunku poszukiwania nowych sposobów zatężania, oczyszczania i rozdzielania różnych rodzajów mieszanin. Obecnie coraz chętniej w różnego rodzaju procesach wykorzystuje się membrany polimerowe. Praca prezentuje wyniki badań nad właściwościami filtracyjnymi i mechanicznymi membran kapilarnych z polipropylenu wykonanych na Wydziale Inżynierii Chemicznej i Procesowej Politechniki Warszawskiej.

EN

Necessity of environmental protection and economic reasons cause that researchers try to find new ways of densification, purification and separation. Nowadays, polymeric membranes are commonly used for this purpose. The paper presents results of research on filtration and mechanical properties of capillary membranes made at the Faculty of Chemical and Process Engineering, Warsaw University of Technology.

6

New ceramic superionic materials for IT-SOFC applications

80%

Paściak G. , Chmielowiec J. , Bujło P.

Materials Science Poland

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2005

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tom Vol. 23, No. 1

209--219

EN

The syntheses of new ceramic superionic materials based on Bi2O3 (BIMEVOX and ?-Bi2O3), their elemental analyses, thermodynamical stability, and electrical properties are presented. The materials show high ionic conductivities (ca. 0.1 S/cm) at a relatively low temperature (600 °C), which makes them applicable as electrolytes in IT-SOFC fuel cells. Ionic conductivity measurements of these materials were performed with the DC (four probe configuration) and IS (impedance spectroscopy) methods, whereas structural research was performed using X-ray spectroscopy. Investigations of the thermodynamic stability of the elaborated materials in oxygen-free atmosphere were also performed. Based on the results of the investigations, the most suitable superionic conductors for fuel cell were selected.

7

Affinity of new anticancer agent, DB-174, to membranes and HSA determined by fluorescence spectroscopy methods

80%

Kruszewski S. , Bom D. , Ziomkowska B. , Cyrankiewicz M.

Optica Applicata

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2006

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tom Vol. 36, nr 2-3

199-207

EN

The application of fluorescence spectroscopy methods to determining the properties of camptothecins promising anticancer agents are described in this paper. The fluorescence anisotropy measurements provide useful information about the binding of camptothecin and its analogues to cell membranes and human serum albumin (HSA) that is important for potential clinical applications of these agents, and permits the selection from many camptothecin analogues those ones exhibiting desirable biomedical properties. Binding properties of 7-trimethylsilyl-ethyl-10 hydroxy-camptothecin are the subject of this paper.

8

Nanocomposite membranes obtained by a hot pressing method

80%

Stodolak-Zych E. , Sas Ł.

Engineering of Biomaterials

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2016

|

tom Vol. 19, no. 138 spec. iss.

56

9

Anomalously large kinetic isotope effect

80%

Krinkin D.

Open Chemistry

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2007

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tom 5

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nr 4

1019-1063

EN

Activated diffusion of water between macromolecules in swollen cellulose is accompanied by anomalously high kinetic isotope effects of oxygen. The separation factor of heavy-oxygen water (H218O /H216O) is thousands of permilles instead of tens of permilles according to modern Absolute Rate Theory. This anomalous separation under usual conditions is disguised by the opposing process of very fast equalization to equilibrium through water-filled cellulose pores. This process is quicker by approximately 3 orders of magnitude than diffusion through the cellulose body. As a consequence, this opposition-directed equalization virtually eliminates the results of isotope separation. To reveal this anomaly it is necessary to suppress equalization, which was the primary problem for both discovery of this anomaly and its investigation. The method of investigating the anomalous separation in cellulose was developed with suppression of this negative influence. Discussion of the theoretical nature of the anomalous kinetic isotope effect is presented. This theoretical study would probably permit the discovery and use for isotope separation of the anomalously high isotope effect for other chemical elements, in particular, for those heavier than oxygen. [...]

10

STRUCTURAL AND SWELLING PROPERTIES OF HYDROGEL MEMBRANES BASED ON CHITOSAN CROSSLINKED WITH GLUTARALDEHYDE AND SODIUM TRIPOLYPHOSPHATE

80%

Gierszewska-Drużyńska M. , Ostrowska-Czubenko J.

Progress on Chemistry and Application of Chitin and its Derivatives

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2015

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tom 20

43-53

EN

Chemically and physically crosslinked chitosan hydrogel membranes were obtained by treatment of chitosan (Ch) with glutaraldehyde (GA) and with GA and subsequently with sodium tripolyphosphate (TPP). The formation of covalent and ionic crosslinks between Ch, GA and ionic TPP was confirmed by FTIR spectroscopy. The studies of dynamic swelling behaviour of synthesized membranes in buffer solutions of different pH (1.0, 7.4, 9.0) indicated that the swelling process obeyed a second-order kinetics. Values of an apparent swelling rate constant for Ch/GA and Ch/GA/TPP membranes were of the same order for acidic and neutral swelling media but they increased for alkaline solutions.

11

A four-node 3d isoparametric membrane element

80%

Ambroziak A. , Kłosowski P.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2006

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tom Vol. 10, No 1

35-47

EN

The paper presents a non-linear finite element procedure for analysis of membrane structures. A four-node quadrilateral finite element is formulated to represent a general curved elastic geometrically non-linear surface. The described isoparametric element is CO-continuous, of constant thickness, and assumes a plane stress criterion. A simple numerical example is presented as an application of the described theory.

12

The effect of bioactive glass particle size on properties of poly(ε-caprolactone) based membranes

80%

Dziadek M. , Zagrajczuk B. , Pukas K. , Cholewa-Kowalska K.

Engineering of Biomaterials

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2016

|

tom Vol. 19, no. 138 spec. iss.

66

13

EQUILIBRIUM SWELLING STUDY OF CROSSLINKED CHITOSAN MEMBRANES IN WATER, BUFFER AND SALT SOLUTIONS

80%

Gierszewska M. , Ostrowska-Czubenko J.

Progress on Chemistry and Application of Chitin and its Derivatives

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2016

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tom 21

55-62

EN

Physically crosslinked membranes were prepared by treating chitosan (Ch) with pentasodium tripolyphosphate (TPP) at different reaction conditions. The equilibrium swelling ratio, Seq, of Ch/TPP membranes in water, buffer and salt solutions at 37 C were determined. The experimental data indicated, that Seq depended on pH of buffer solution and type and concentration of salt solution. Swelling capacity in water depended on the content of TPP ions in the membrane and crosslinking density

14

The importance of membranes to modern technologies

80%

Kołtuniewicz A.

Environment Protection Engineering

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1999

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tom Vol. 25, nr 1-2

7-20

EN

The paper points out that membranes play increasingly important role in different branches of human friendly technologies. Membrane processes are implemented in industry, in energetic and environmental protection, where the formerly used cleaning technologies are recently replaced by modern clean technologies. Effective separation of different components from industrial sewage or wastes makes it possible to recover raw materials or to recycle chemicals, cleaning agents, etc. This enables us to improve environment and to reduce total costs simultaneously. However, membranes are still used in cleaning technologies for wastewater treatment, remediation of contaminated soils, purification of ground waters, cleaning of industrial gases and sewage. Besides membranes are also used for the improvement of human health, e.g. artificial organs (kidney, lunch. pancreas and skin), pyrogens removal, blood processing and controlled release of medicines. Membranes are successfully used in the production of healthful and tasteful food. Agriculture uses membranes in hydroponics or for controlled release of fertilizers, herbicides, pesticides, insecticides, and pheromones. This way of delivery protects soils and ground waters against penetration of chemicals. This above-mentioned membrane applications are reviewed.

15

Porous ion exchange membranes

80%

Bryjak M. , Poźniak G.

Environment Protection Engineering

|

1998

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tom vol. 24, nr 3-4

85-95

EN

This paper presents several methods allowing preparation of porous membranes with limited ability to be fouled. The methods are based on membrane surface modification by anchoring some ionogenic groups. Unique properties of these membranes enabled us to specify a peculiar class of membranes and call it Porous Ion Exchange Membranes (PIEMs). In the paper, the methods for PIEM preparation are described. They are based on our studies and some literature data. In the methods presented, the following techniques were applied: polymer blending, selective polymer etching, blend syneresis, and modification of membrane surface by chemical or plasma treatment.

PL

Przedstawiono metody otrzymywania membran porowatych o przedłużonym czasie użytkowania. Omówione metody modyfikacji materiału membranowego umożliwiają otrzymanie membran odpornych na zatruwanie. Przegląd metod modyfikacji oparto głównie na własnych opracowaniach. Ze względu na zdecydowanie różne zachowanie się modyfikowanych membran w procesie filtracji nazwano je Porowatymi Membranami Jonowymiennymi (PIEM). Przedstawiono metody otrzymywania PIEM oparte na takich technikach jak: mieszanie polimerów, selektywne usuwanie jednego z polimerów z mieszaniny, inwersja faz czy separacja polimerów z ich mieszanin. Powierzchnię otrzymanych porowatych membran modyfikowano chemicznie lub plazmowo.

16

Biomimetic fibrous composite membranes for bone tissue engineering

80%

Rajzer I. , Chrzanowski W. , Biniaś W. , Sarna E. , Janicki J.

Engineering of Biomaterials

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2010

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tom Vol. 13, no. 93

2--5

EN

One of the major challenges in biomaterials and tissue engineering is to guide the cell differentiation to the specific phenotype, therefore allow the formation of the tissue of certain type. This can be achieved by manipulating the structural, geometrical and chemical characteristics of the tissue engineering constructs. In our studies we concentrated on the chemical modifications of the polymer based materials for tissue engineering. The primary aim of our study was to incorporate nano size hydroxyapatite (n-HAp) crystals into the polymer fibres and form membranes, which are a core to the construction of novel scaffolds for tissue regeneration. We hypothesised that n-HAp will significantly improve the bioactivity of the polymer based membranes due to the presence of chemical cues. We developed a simple method to fabricate PLDL/n- HAp composite membranes using electrospinning process. The investigation showed that the incorporation of the n-HAp particles in the polymer spinning solution induced changes in the material surface morphology. FTIR analysis confirmed the presence of apatite on the surface of the membrane' fibers. The bioactivity analysis, which was based on SEM observation of the membranes surface, showed that after only 7 days immersion in SBF, the PLDL/n-HAp -membranes were completely covered by the apatite layer. This was not observed for pure PLDL membranes.

17

In vitro evaluation of poly(L-lactide-co-glycolide) membrane

80%

Krok M. , Hess R. , Wojak I. , Kościelniak D. , Scharnweber D. , Pamuła E.

Engineering of Biomaterials

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2010

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tom Vol. 13, no. 94

7--10

EN

The aim of this study was to prepare and evaluate the properties of a new membrane dedicated for the treatment of bone defects in periodontology according to guided tissue regeneration (GTR) technique. The first part of this study was to prepare the membrane from resorbable poly(L-lactide-co-glycolide) (PLGA) and verify its microstructure. Biological evaluation was lead using the cells interesting from the point of view of GTR, e.g. human fibroblasts and mesenchymal stem cells (hMSC). It was found that the obtained membrane has asymmetric microstructure and defined pore size. Cell culture experiments show that the membrane is biocompatible with fibroblasts and hMSC. Both types of cell proliferated well on the membrane. HMSC cultured on the membrane exhibited better osteogenic differentiation and higher mineralization as compared to control tissue culture polystyrene.

18

Carbon nanocomposite membrane with bioactive fillers

80%

Stodolak-Zych E. , Szatkowski P. , Błażewicz M.

Engineering of Biomaterials

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2016

|

tom Vol. 19, no. 138 spec. iss.

57

19

ADSORPTION OF CADMIUM IONS ON CHITOSAN MEMBRANES: KINETICS AND EQUILIBRIUM STUDIES

80%

Zielińska K. , Chostenko A. G. , Truszkowski S.

Progress on Chemistry and Application of Chitin and its Derivatives

|

2010

|

tom 15

73 - 78

EN

The presence of toxic heavy metals in industrial wastewater is a serious pollution problem. The ability of chitosan membranes as an adsorbent for cadmium ions in aqueous solution was studied. Experiments were carried out as function of contact time and concentration of cadmium ions. This study has shown that chitosan is capable of removing cadmium from aqueous solution. The removal efficiency depends on reaction time and concentration of cadmium. The Langmuir and Freundlich adsorption models were applied to describe the isotherms and isotherm constants. Equilibrium data agreed very well with the Langmuir model. The maximum adsorption capacity of the Langmuir isotherm equation was 94 mg/g and the Langmuir adsorption equilibrium constant was 1.6 × 10-3 dm3/mg at 25 °C.

20

Badanie wpływu warunków procesowych na przebieg mikrofiltracji zanurzeniowej z użyciem włókien polipropylenowych typu hollow fiber

80%

Luśnia E. , Szwast Z. , Szwast M. , Piątkiewicz W.

Inżynieria i Aparatura Chemiczna

|

2010

|

tom Nr 2

73-74

PL

Badano zanurzeniowe filtry membranowe wykorzystujące napór nadawy jako siłę napędową procesu. Filtry takie nie wymagają obudowy ciśnieniowej. Badano moduły zawierające 342 kapilary membranowe o długości czynnej 615 mm ustawione pionowo lub poziomo. Stosowano różne podciśnienia po stronie permeatu. Badano też wpływ napowietrzania na proces. Nie wykazano wpływu ustawienia modułów na jakość procesu. Stwierdzono pozytywny wpływ napowietrzania powodującego destrukcję osadu na powierzchni membran.

EN

Submerged membrane filters were tested under the water head driving force. Such filters do not require pressure vessels. Modules with 345 membrane capillaries of 615 mm in length were examined in a vertical and horizontal position. Different low pressures at permeate side, including the presence of aeration, were checked. Impact of module position on its performance was not proved, however a positive effect on the cake destruction caused by aeration was observed.