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Organosulfonic Acid Functionalised Silica Mesostructured Cellular Foams - Efficient Acidic Catalysts For Reactions Of Esterification, J. Mrowiec-Bialon, K. Maresz, Janusz J. Malinowski, Andrzej B. Jarzębski Dec 2007

Organosulfonic Acid Functionalised Silica Mesostructured Cellular Foams - Efficient Acidic Catalysts For Reactions Of Esterification, J. Mrowiec-Bialon, K. Maresz, Janusz J. Malinowski, Andrzej B. Jarzębski

Janusz J. Malinowski

Structural and catalytic properties of sulfonic acid functionalised silica mesostructured cellular foams (MCFs) prepared using different precursors of sulfonic acid groups were investigated. Catalytic activity tested in the esterification of butanol with acetic acid was found to decrease in the order MCF-et-ph-SO3H> MCF-ph-SO3H> MCF-propyl-SO3H. Owing to excellent structural stability, the catalysts developed can be used repeatedly without loss of activity during several cycles.

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Structure Analysis Of Nanocrystalline Mgo Aerogel Prepared By Sol-Gel Method, G. Dercz, L. Pajak, K. Prusik, R Pielaszek, Janusz J. Malinowski, Wojciech Pudło Dec 2006

Structure Analysis Of Nanocrystalline Mgo Aerogel Prepared By Sol-Gel Method, G. Dercz, L. Pajak, K. Prusik, R Pielaszek, Janusz J. Malinowski, Wojciech Pudło

Janusz J. Malinowski

Wet gel obtained by sol-gel technique was dried in supercritical CO2 to prepare hydrated form of magnesium oxide. Calcination at 723 K under vacuum yielded nanocrystalline MgO aerogel. Structure studies were performed by X-ray diffraction, scanning and transmission electron microcopies. Electron microscopy images reveal rough, unfolded and ramified structure of solid skeleton. Specific surface area SBET was equal to 238 m2/g. X-ray pattern reveals the broadened diffraction lines of periclase, the only crystalline form of magnesium oxide. The gamma crystallite size distribution was determined using FW 1/5/4/5 M method proposed by R. Pielaszek. The obtained values of and ó (measure …

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Insisting On Truth At The Expense Of Conceptualization: Can Engineering Portfolios Help?, Ozgur Eris Dec 2005

Insisting On Truth At The Expense Of Conceptualization: Can Engineering Portfolios Help?, Ozgur Eris

Ozgur Eris

Teaching and promoting conceptual thinking in engineering education is challenging. Two recently introduced design thinking models are compared in order to explore the reasons behind this challenge. The comparison results in key distinctions between divergent and convergent thinking, and between concept and knowledge domains. The differentiating principle is shown to be a common principle of the two models, truth-value, or logical status, of the propositions that engineers make. Building on this insight, divergent thinking by inquiry is identified as a mechanism for promoting conceptual thinking, and a specific implementation of engineering portfolios is proposed as a pedagogical tool.

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The Effective Approach For Recovery Of Methyl-Substituted 1,3-Dioxane From Aqueous Media, Janusz J. Malinowski, Andrew J. Daugulis Jan 2002

The Effective Approach For Recovery Of Methyl-Substituted 1,3-Dioxane From Aqueous Media, Janusz J. Malinowski, Andrew J. Daugulis

Janusz J. Malinowski

The solvent extraction has been successfully applied to the recovery of methyl-substituted 1,3-dioxane from the aqueous reaction media. Aromatic hydrocarbons used as extractants allowed the removal, from the aqueous phase, of up to 75% of dioxane formed in the one stage reactor–extractor. The concept could be included in a downstream separation scheme for the isolation of 1,3-propanediol from a dilute aqueous solution using reversible reaction of the diol with acetalaldehyde.

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Two-Phase Partitioning Bioreactors In Fermentation Technology, Janusz J. Malinowski Jan 2001

Two-Phase Partitioning Bioreactors In Fermentation Technology, Janusz J. Malinowski

Janusz J. Malinowski

The two-phase partitioning bioreactor concept appears to have a great potential in enhancing the productivity of many bioprocesses. The proper selection of an organic solvent is the key to successful application of this approach in industrial practice. The integration of fermentation and a primary product separation step has a positive impact on the productivity of many fermentation processes. The controlled substrate delivery from the organic to the aqueous phase opens a new area of application of this strategy to biodegradation of xenobiotics. In this review, the most recent advances in the application of two-liquid phase partitioning bioreactors for product or …

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Reactive Extraction For Downstream Separation Of 1,3-Propanediol, Janusz J. Malinowski Jan 2000

Reactive Extraction For Downstream Separation Of 1,3-Propanediol, Janusz J. Malinowski

Janusz J. Malinowski

The downstream separation of 1,3-propanediol from dilute aqueous solution was studied. A process combining reversible reaction of 1,3-propanediol with acetaldehyde to 2-methyl-1,3-dioxane and a simultaneous extraction of the product by organic solvent appears to be technically feasible and attractive. The dioxane yield was 91-92%, the overall conversion of 1,3-propanediol was ca. 98%, and recovery of dioxane into the organic extractant was 75%.

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Evaluation Of Liquid Extraction Potentials For Downstream Separation Of 1,3-Propanediol, Janusz J. Malinowski Jan 1999

Evaluation Of Liquid Extraction Potentials For Downstream Separation Of 1,3-Propanediol, Janusz J. Malinowski

Janusz J. Malinowski

The application of liquid-liquid extraction for the downstream separation of 1,3-propanediol from dilute aqueous solutions has been tested. Preliminary solvent screening was performed using the group contribution method. Experimental verification of the predictions revealed that the distribution of 1,3-propanediol into organic solvents is not good enough to make simple extraction efficient.

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Two-Component Aerogel Adsorbents Of Water Vapour, J. Mrowiec-Bialon, A. B. Jarzebski, A. I. Lachowski, Janusz J. Malinowski Dec 1997

Two-Component Aerogel Adsorbents Of Water Vapour, J. Mrowiec-Bialon, A. B. Jarzebski, A. I. Lachowski, Janusz J. Malinowski

Janusz J. Malinowski

Two-component SiO2–CaCl2 or SiO2–LiBr aerogels exhibit outstanding adsorption capacities of water vapour, in the range of 0.9–1.1 kg H2O/kg adsorbent. Adsorption properties remain stable during repeated adsorptionrdesorption cycles

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Preparation Effects On Zirconia Aerogel Morphology, J. Mrowiec-Bialon, L. Pajak, A. B. Jarzebski, A I. Lachowski, Janusz J. Malinowski Dec 1997

Preparation Effects On Zirconia Aerogel Morphology, J. Mrowiec-Bialon, L. Pajak, A. B. Jarzebski, A I. Lachowski, Janusz J. Malinowski

Janusz J. Malinowski

Small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) of zirconia aerogels’ morphology show a strong effect of the mode of supercritical drying on zirconia structure and a remarkable similarity of aerogels obtained using either acetic or nitric acid as process moderators. A fine polymeric structure in sub-nanometer scales and 20-nm polymeric aggregates were observed in aerogels obtained from the supercritical CO2 route. More massive polymeric structure in nanometer scales resulted from the standard high temperature process. Upon calcination at 773 K, all samples proved to be quite similar in morphology but a bit different in crystal structure.

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Effective Hybride Adsorbents Of Water Vapour By The Sol-Gel Method, J. Mrowiec-Bialon, A. B. Jarzebski, A. I. Lachowski, Janusz J. Malinowski, Y. I. Aristov Dec 1996

Effective Hybride Adsorbents Of Water Vapour By The Sol-Gel Method, J. Mrowiec-Bialon, A. B. Jarzebski, A. I. Lachowski, Janusz J. Malinowski, Y. I. Aristov

Janusz J. Malinowski

The SiO2/CaCl2 hybrid porous materials were obtained by the two-step hydrolysis and condensation of tetraethoxysilane with (a) replacement of ethanol from alcogel by supercritical CO2 to obtain aerogel morphology and (b) drying alcogel at ambient to obtain xerogel structures. Aerogels and xerogels containing ~17 and ~30 wt % of CaCl2 (dry matter) were prepared and investigated for adsorptivity of water vapor to obtain sorption capacities in excess of 1 kg of water/kg of adsorbate. The adsorbates obtained can be dried and reused. No notable loss in adsorption capacity was observed during 50 cycles.

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Thermostability And Esterification Activity Of Mucor Javanicus Lipase Entrapped In Silica Aerogel Matrix And In Organic Solvents, T. Antczak, J. Mrowiec-Bialon, S. Bielecki, A. B. Jarzebski, Janusz J. Malinowski, A. I. Lachowski, E. Galas Dec 1996

Thermostability And Esterification Activity Of Mucor Javanicus Lipase Entrapped In Silica Aerogel Matrix And In Organic Solvents, T. Antczak, J. Mrowiec-Bialon, S. Bielecki, A. B. Jarzebski, Janusz J. Malinowski, A. I. Lachowski, E. Galas

Janusz J. Malinowski

The lipase of Mucor javanicus (now M. circinelloides) entrapped in silica matrix by the sol-gel method esterified primary and secondary alcohols with conversions ranging from 30 to 35% and 10 to 15%, respectively. Loss in activity of the preparations after incubation at 100°C for 1 h with petroleum ether, dodecane, 1-heptanol or oleyl alcohol was about half of that observed for the native lipase.

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Morphology Of Silica Aerogels Obtained From The Process Catalyzed By Nh4f And Nh4oh, J. Mrowiec-Bialon, L. Pajak, A. B. Jarzebski, A. I. Lachowski, Janusz J. Malinowski Dec 1996

Morphology Of Silica Aerogels Obtained From The Process Catalyzed By Nh4f And Nh4oh, J. Mrowiec-Bialon, L. Pajak, A. B. Jarzebski, A. I. Lachowski, Janusz J. Malinowski

Janusz J. Malinowski

Twelve samples of silica aerogels were synthesized using different concentrations of catalysts (NH4F,NH4OH), and their morphology was investigated by means of small-angle X-ray scattering (SAXS), N2 adsorption, and transmission electron microscopy. Both SAXS and the nitrogen adsorption method consistently show a different influence of the catalysts; fluoride anions promote formation of a tenuous branched-polymeric structure, with mass fractal dimension Dm = 2.3-2.5, while addition of hydroxyl ions results in a sparser structure (Dm = 2.1-2.2) self-similar over a narrower range. The morphology of aerogels obtained from the process catalyzed by fluoride hydroxide resembles that of aerogels produced by the two-step …

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Exoerience With The Analysis Of Small Signal Stability In Longitudinal Power Systems: A Case Study With The Mexican Interconnected System, Arturo Roman Messina Jan 1995

Exoerience With The Analysis Of Small Signal Stability In Longitudinal Power Systems: A Case Study With The Mexican Interconnected System, Arturo Roman Messina

A. R. Messina

In this paper a fundamental study of the small signal stability characteristics of a longitudinal system representing a major equivalent of the Mexican power system is presented. The special characteristics of the Mexican system are emphasized and a number of studies regarding the nature and sources of low frequency oscillations are discussed. These studies reveal the emergence of an undamped swing mode #tvolving the interaction of several machines and their controllers spread out over a large geographical area. The influence of system structure and loading, load effect and the

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Potentials And Prospects For Application Of Supercritical Fluid Technology In Bioprocessing, Andrzej B. Jarzebski, Janusz J. Malinowski Dec 1994

Potentials And Prospects For Application Of Supercritical Fluid Technology In Bioprocessing, Andrzej B. Jarzebski, Janusz J. Malinowski

Janusz J. Malinowski

Recent investigations on the application ofsupercritical (SC)Jluid technology in bin- andfood chemistry are reviewed. The gas-antisolvent crystallization and rapid expansion of SC&id emerge as attractive methods for micron-size particle formation. Also gainingground is enzymic catalysis in SC CO,, which offers the possibility of integrated synthesis-product recovery processes. These processes, successfully tested on a lahoratoly scale, need further scale-up and optimization. Supercritical CO, has proven to be unfriendly, or even toxic, for living microorgcmisms, which precludes direct fermentation in dense CO, but does not rule out other useful applications.

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Salts Effects In Liquid-Liquid Extraction Of Ethanol, 1- Butanol And Acetone From Dilute Aqueous Solutions, Janusz J. Malinowski, A. J. Daugulis Jan 1994

Salts Effects In Liquid-Liquid Extraction Of Ethanol, 1- Butanol And Acetone From Dilute Aqueous Solutions, Janusz J. Malinowski, A. J. Daugulis

Janusz J. Malinowski

Experimental studies were performed to assess the effect of salt addition on the extraction of 1-butanol, ethanol and acetone from dilute aqueous solutions using cyclopentanol, n-valeraldehyde, tert-amyl alcohol, and Adol 85NF as extractants. The liquid-liquid partitioning was examined for a few strong electrolytes in a broad range of concentrations. Results demonstrate that the distribution coefficient and selectivity in systems with reduced water activity resulting from salt addition were markedly increased. These observations can be qualitatively explained on the basis of the hydration theory. It was also determined that strong electrolytes added to the aqueous feed reduced extractant solubility in the …

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Continuous Fermentation Of High-Strength Glucose Feeds To Ethanol, A. J. Daugulis, D. B. Axford, B. Ciszek, Janusz J. Malinowski Dec 1993

Continuous Fermentation Of High-Strength Glucose Feeds To Ethanol, A. J. Daugulis, D. B. Axford, B. Ciszek, Janusz J. Malinowski

Janusz J. Malinowski

Aqueous feeds of 413 and 495 g/L glucose were fermented to ethanol at 90-95% conversion in a continuous flow extractive fermentation system with cell recycle. Compared to the continuous conventional fermentation of a 195 g/L glucose medium, the volumetric productivity was more than doubled in extractive mode, with no deleterious effects on cell viability, specific glucose consumption rate or ethanol yield. The use of an effective, biocompatible and stable in situ extractant with flash vaporization can also produce a concentrated ethanol vapour stream, reducing distillation costs of the product.

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Micro And Macromorphology Of Recycled Fiber And Wood, Douglas D. Stokke Jan 1992

Micro And Macromorphology Of Recycled Fiber And Wood, Douglas D. Stokke

Douglas D. Stokke

Wood is a major industrial raw material, with U.S. consumption approaching that of aluminum, plastics, cement, and steel combined. Partially as a result of the magnitude of wood and wood products in use, these products constitute a substantial portion of the solid waste stream. In order to reduce the amount of wood and wood fiber disposed in landfills, efforts to recycle these materials into useful products such as structural composites are needed. The success of such conversion depends in part on knowledge of the morphological characteristics of various sources of secondary wood and wood fibers, and the influence of wood …

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