Wyniki wyszukiwania - BazTech

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Mass transport and changes in the saccharide profile during osmotic dehydration of apricot and chokeberry fruits

Pluta Małgorzata, Klewicki Robert

Biotechnology and Food Science

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2022

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Vol. 84, nr 1

19--32

EN

The aim of the study was to determine the effect of osmotic dehydration in sucrose solution on the level and profile of the main saccharides in frozen chokeberry and apricot. A 50°Bx sucrose solution at a temperature of 25, 35, 45 and 55°C was used in the tests. The influence of temperature and dehydration time on the dry matter content in the tested fruits was demonstrated. Both in apricot and chokeberry the highest increase was recorded in the first hour of the process, for apricots to the level of 25.1-32.4%, for chokeberry 30.4-33.4%. The use of the highest temperature (55°C) increased the content of glucose and fructose while reducing the amount of sucrose (hydrolysis); at 25-35°C the opposite effect was obtained. At low temperatures, chokeberry was not very susceptible to migration of sucrose. Also, the transport of water was not intense. There was no correlation between the temperature of the process and the increase in dry matter in the sample. The greatest loss of water, i.e. 1 g H2O/g i.d.m., occurred after five hours at 55°C. Under analogous conditions, apricots showed a higher water loss, at the level of 4.68 g H2O/g i.d.m. At 25°C, after the first hour of dehydration, the energy value of saccharides in apricots was 315 kJ/100 g; at 55°C, after 3÷5 hours it fluctuated around 500 kJ/100g. Dehydrated chokeberry was characterized by approx. 1.5÷2 times lower energy value than apricot.

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Wykorzystanie chromatografii preparatywnej do wyodrębniania galaktozylowych pochodnych hydroksykwasów

Wojciechowska Aleksandra, Klewicki Robert, Sójka Michał, Klewicka Elżbieta

Przemysł Chemiczny

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2020

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T. 99, nr 2

293--297

PL

Przedstawiono wyniki badań procesu wyodrębniania galaktozylowych pochodnych hydroksykwasów, uzyskanych w wyniku enzymatycznej galaktozylacji. Wykorzystano kolumnę preparatywną, do której wprowadzano mieszaninę poreakcyjną po wstępnym odsoleniu. W celu oddzielenia sacharydów frakcje z rozdziału chromatograficznego dodatkowo oczyszczano, wykorzystując jonity. Stwierdzono, że metoda ta może być stosowana do pozyskiwania produktów galaktozylacji hydroksykwasów o czystości ok. 80%.

EN

Three hydroxyacids (gluconic, glucoheptonic or ascorbic) were reacted with β-galactosidase at 37°C, pH 6.9-7.0 and for 9 h in presence of an enzyme. The transgalactosilationproducts were sepd. in a column filled with a com. cation exchanger at 40°C and using water as the mobile phase. To obtained saccharide-free products, cationic and anionic exchangers were used. An increase in purity up to 80% was achieved for gluconic and glucoheptonic acid derivatives.

3

Modular Test Stand for Fatigue Testing of Aeronautical Structures - Verification of Assumptions

Leski Andrzej, Wronicz Wojciech, Kowalczyk Piotr, Szmidt Michał, Klewicki Robert, Włodarczyk Karol, Uliński Grzegorz

Fatigue of Aircraft Structures

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2020

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Iss. 12

78--91

EN

The Modular Test Stand was developed and manufactured to decrease the cost of fatigue testing and reduce the time of its completion as well as to enable testing specimens under more complex load conditions. The stand consists of three connected sections, similar to a wing box, all being loaded in the same way. Thanks to that, several specimens can be tested simultaneously. This configuration requires that stress and strain distribution should be reasonably uniform, as assumed in the design stage. The structure can be loaded with bending or torsion. A whole section, selected structural node or a specimen mounted in the structure as well as a repair or a sensor can be a test object. Two stands, one for bending and one for torsion were prepared. This paper presents the verification of the assumed strain and stress distributions on the skin panels. The measurements were performed with the use of Digital Image Correlation (DIC) as well as strain gauges. DIC measurements were performed on one skin panel of the central section. Five strain gauge rosettes were installed on both panels of the one section. In addition, one rosette was applied to one skin panel in each of two other sections. Measurements were performed on the stand for torsion as well as on the stand for bending. The results of DIC analysis and strain gauge measurement during torsion show uniform shearing strain distributions on the panels. During bending, on the tensioned side, the strains obtained indicate quite uniform strain distributions. On the compressed side, local buckling of the skin panels results in high strain gradients. Strain levels obtained with the use of a DIC analysis and strain gauge measurements were similar. Moreover, horizontal displacements of markers in the spar axis during bending was determined based on a series of photographic. The deflection line obtained in this way has a shape similar to arc, which is characteristic of the constant bending moment. The stand was tested with torsional and bending loads in order to verify the design assumptions. The results of strain distributions on the skin panels with the use of DIC and strain gauges as well as the deflection line of the spar axis indicate that the Modular Test Stand performs as assumed and can be used for tests.