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Lev J.,Ustav Techniky a Automobilove Dopravy | Kalhotka L.,Mendel University in Brno | Cerny M.,Ustav Techniky a Automobilove Dopravy
Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis

The article describes an experimental study dealing with the possibility of nanotextile materials usage for microbiologically contaminated water filtration. The aim of the study is to verify filtration ability of different nanotextile materials and evaluate the possibilities of practical usage. Good detention ability of these materials in the air filtration is the presumption for nanotextile to be used for bacteria filtration from a liquid. High nanotextile porosity with the nanotextile pores dimensions smaller than a bacteria size predicates the possibility of a successful usage of these materials. For the experiment were used materials made from electrospinning nanofibres under the label PA612, PUR1, PUR2 s PUR3 on the supporting unwoven textiles (viscose and PP). As a model simulation of the microbial contamination, bacteria Escherichia coli was chosen. Contaminated water was filtered during the overpressure activity of 105Pa on the input side of the filter from the mentioned material. After three-day incubation on the nutrient medium, cultures found in the samples before and after filtration were compared. In the filtrated water, bacteria E.coli were indicated, which did not verify the theoretical presumptions about an absolut bacteria detention. However, used materials caught at least 94% of bacteria in case of material PUR1 and up to 99,996% in case of material PUR2. These results predict the possibility of producing effective nanotextile filters for microbiologically contaminated water filtration. Recommendation: For the production of materials with better filtrating qualities, experiments need to be done, enabling better understanding of the bacteria detention mechanisms on the nanotextile material, and parameters of the used materials that influence the filtrating abilities need to be verified. Source

Severa L.,Mendel University in Brno | Buchar J.,Mendel University in Brno | Nedomova S.,Ustav Techniky a Automobilove Dopravy | Sustova K.,Ustav Techniky a Automobilove Dopravy
Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis

The results of raw whey rheological behavior investigation - particularly viscosity, dependence on temperature, time, and share rate, are presented. The whey samples have been examined under temperature ranging from 17 to 90 °C and under share rate ranging from 0.34 to 68 S"1. The measurements have been performed using rotary digital viscometer (concentric cylinders geometry). The material was found to be temperature dependent (non-linearly), time dependent and shear thinning. Received data have been successfully characterized by several mathematical models (power, exponential, and polynomial) in MATLAB software with satisfying correlations between experimental and computed results. Following correlations have been achieved: temperature dependence with r 2 = 0.993 using polynomial model, time dependence with r 2=0.985 using power model, and shear thinning behavior r 2=0.998 using power model. The results are quite useful for practical design of technological equipment such as pumps and piping. Source

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