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Rheological measurements of disintegrated activated sludge

100%

Travnicek P., Vitez T., Junga P., Krcalova E., Sevcikova J., Marecek J., Machal P.

Polish Journal of Environmental Studies

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2013

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tom 22

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nr 4

Our paper deals with the description of the rheological properties of activated sewage sludge before and after disintegration. There is an assumption that disintegrated activated sewage sludge is able to change rheological properties. These changes probably cause the modification of the structure of activated sewage sludge after disintegration. The reason is that during disintegration, cell walls of organisms (from which the activated sewage sludge is composed) are disturbed. Currently there are not published many papers that deal with rheological properties of disintegrated activated sewage sludge. There is therefore no opportunity to confront our assumption with papers of other authors. The sample of activated sewage sludge was collected from aeration tank of the wastewater treatment plant for 10,000 population equivalent (PE). In our work the following rheological properties were described: temperature dependence on viscosity and the shear stress dependence on shear rate. On the basis of measured data Arrhenius mathematical model has been applied. By using this mathematical model the activation energy has been obtained.

2

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Removal of chromium by biosorption method (chitosan)

84%

Abatneh Y., Sahu O.

International Letters of Natural Sciences

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2014

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tom 03

Discharge of metal containing effluents into water has been a cause of major concern. Traditional treatment methods are proving to be ineffective and expensive. Chitosan was studied as a potential biosorbent due to its positive charge and relatively low cost. The study involves evaluating the metal binding performance of chitosan in a Polymer Enhanced Diafiltration (PEDF) system which uses an ultra filtration membrane to retain the chitosan which, in turn, binds the metal, thereby preventing passage into the permeate stream. Conditions for binding such as pH, concentration of polymer and chromium were studied. Optimal performance was obtained when the system was operated at pH values lower than the pKa of chitosan i.e. 6.3. Using 6 g/L chitosan at pH 4.0, chromium concentration was reduced to less than 1mg/L from a feed concentration of 20 mg/L. Equilibrium dialysis experiments were done to study the kinetics of binding and the uptake of metal per gram of polymer. Rheological measurements demonstrated that in the presence of 1-100 mM chromate, chitosan was found to be slightly shear thickening at low concentrations such as 4 g/L and 6 g/L whereas it was slightly shear thinning at higher concentrations like 12 g/L and 20 g/L This suggests that neutralization of chromium anions is due to the interaction of multiple chitosan molecules. This result is consistent with the relatively stiff nature of the polysaccharide. Overall, this study suggests that some modification of the native polymer would be required to improve uptake and make it an industrially workable process.

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The effect of pH and stabilization time on apparent viscosity of aqueous dispersion of wholemeal barley flour

67%

Zarzycki P., Wirkijowska A., Sobota A., Sykut-Domanska E.

Acta Agrophysica

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2019

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tom 26

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nr 2

4

Properties of starch - sugar - water systems studied by dynamic rheological measurements

67%

Sikora M.

Polish Journal of Food and Nutrition Sciences

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2001

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tom 10

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nr 1

Saturated aqueous solutions of D-glucose, D-fructose and sucrose were blended with solid granules of corn, waxy corn and tapioca starches. Systems deficient in water were obtained, properties of which were studied by dynamic rheological measurements. The properties of systems obtained at different proportions of saturated sugar solutions to starch were characterized. It was concluded that desired rheological properties (fluidity of blends) can be achieved by adjusting relevant quantity of plasticizers (different sugars and water). Similarly, by adjusting the quality and quantity of plasticizers, the phenomenon of "magic trick" (viscoelastic behaviour) can be achieved in the studied systems, however, that property is manifested in a very narrow range of starch-to-saturated sugar solution ratio. For all systems under study, the quantity of saturated solutions of relevant sugars, needed to achieve plasticity of each systems, was depicted. It was also concluded that in order to achieve plasticity with tapioca starch granules, for each 2 g of this starch 1.83 and 1.99 g of saturated solution of D-glucose and sucrose, respectively, are needed. In order to achieve plasticity with granules of waxy corn starch - 2.63 and 2.35 g, respectively, and with granules of corn starch - 3.09 and 2.5 g of saturated solutions of D-glucose and sucrose, respectively, are needed. The systems containing saturated solutions of D-fructose have different relationships. In order to achieve plasticity of blends containing corn, waxy corn and tapioca starch, for each 2 g of starch 2.14; 2.13 and 2.33 g, respectively, of saturated fructose solution is needed.

5

Właściwości fizyczne skrobi ziemniaczanej modyfikowanej kwasem oleinowym

59%

Boruczkowska H., Boruczkowski T., Leszczynski W., Stencel P., Ratajczyk F., Tomaszewska-Ciosk E., Drozdz W.

Zeszyty Problemowe Postępów Nauk Rolniczych

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2010

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tom 557

W niniejszej pracy przeprowadzono reakcję enzymatycznej estryfikacji naturalnej skrobi ziemniaczanej kwasem oleinowym w środowisku tert-butanolu z wykorzystaniem jako biokatalizatora handlowego preparatu immobilizowanej lipazy. Materiał wyjściowy, jak i powstałe modyfikaty poddano analizom w celu oznaczenia ich wybranych właściwości. W reakcji 6 i 12 tygodniowej enzymatycznej estryfikacji oraz w wyniku 6 i 12 tygodniowego przetrzymywania substratów w środowisku kwasu oleinowego uzyskano 4 różne modyfikaty, w tym 2 estry o stopniu podstawienia DS 0,25 i 0,83. Na podstawie przeprowadzonej 2 czynnikowej analizy wariancji porównano między sobą wybrane właściwości reologiczne oraz termiczne otrzymanych modyfikatów oraz porównano je testem t-Studenta z właściwościami materiału wyjściowego (skrobi naturalnej). Stwierdzono istotny wpływ metody wytwarzania modyfikatów na ciepła właściwe przemian fazowych. Dla oleinianu skrobi było one prawie 3-krotnie niższe od ciepła właściwego kompleksu skrobi, które kształtowało się na poziomie -5,98 J·g⁻¹. Wykonane pomiary reologiczne przy pomocy reometru Haake RS 50 Rheostress wykazały między innymi, iż wszystkie badane substancje są cieczami nienewtonowskimi.

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Określenie parametrów reologicznych zaczynów wapiennych z uwzględnieniem zjawiska poślizgu

59%

Kempinski J., Swierzko R.

Acta Scientiarum Polonorum. Formatio Circumiectus

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2016

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tom 15

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nr 3

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Correlation between the physical property, eating quality and the molecular structure of rice-starchy systems

51%

Lii C. Y., Lai V. M. F., Lu S., Tsai M. L.

Żywność Technologia Jakość. Suplement

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1998

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tom 05

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