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  Subjects -> SCIENCES: COMPREHENSIVE WORKS (Total: 374 journals)
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Logo STI Science, Technology and Innovation
Number of Followers: 16  

  This is an Open Access Journal Open Access journal
ISSN (Online) 2544-9125
Published by U of Applied Sciences in Tarnow Homepage  [4 journals]
  • The influence of citric acid on the extraction level of manganese in green
           and black tea infusions

    • Authors: Krzysztof Kleszcz, Katarzyna Michoń
      Pages: 1 - 8
      Abstract: Manganese concentration in green and black tea (10 samples of each type) was determined by means of graphite-furnace atomic absorption spectrometry. Both the dry leaves and the infusions were analysed. The concentration of manganese in dry leaves was in the range of 502–1277 mg · kg−1 for black tea and 798–1906 mg · kg−1 for green one. Since lemon juice is commonly added for tea to enrich its taste, citric acid was used to simulate lemon juice influence on manganese concentration in the infusions. The infusions prepared with and without citric acid addition were analysed and the results showed significant influence of citric acid on manganese leaching. The average extraction levels of manganese from black tea equal 16% (for non-acidified infusions) and 34% (for acidified ones) while these values for green tea equal 13% and 38%, respectively. Statistical evaluation of the results showed that the differences between acidified and non-acidified infusions were statistically significant. High manganese content makes the tea an important source of manganese in human diet.
      PubDate: 2023-10-16
      DOI: 10.55225/sti.504
      Issue No: Vol. 17, No. 1-2 (2023)
       
  • FTIR fingerprint — testing a new representation of the binary
           fingerprint based on FTIR spectra in the prediction of physicochemical
           properties

    • Authors: Kacper Tomaszewski, Rafał Kurczab
      Pages: 9 - 29
      Abstract: The paper deals with the development of a new method for the generation of binary fingerprints based on the Savitzky-Golay (SG) algorithm and first-order derivatives of FTIR spectra, which are then used to create prediction models for selected the physicochemical properties of chemical compounds. Models based on the FEDS (Functionally-Enhanced Derivative Spectroscopy) transformation and raw spectra were used as a reference to determine whether the use of the SG filter and first-order derivatives was worth to further develop. The FTIR spectra of 103 compounds with theoretically determined values of logP, logD and logS were studied. The Tanimoto coefficient and correlation coefficient were used to compare the fingerprints obtained, while the root mean square error (RMSE) was used to assess the quality of the prediction models. Based on the results, it was found that the use of the SG filter and derivatives had a positive effect on the quality of the prediction models for logP and logS, and a negative effect on the quality of the models for logD, compared to the models based on original spectra and FEDS transformation.
      PubDate: 2023-09-15
      DOI: 10.55225/sti.492
      Issue No: Vol. 17, No. 1-2 (2023)
       
  • Characteristics of the oxygen molecule activation process on 3d selected
           transition metals — DFT calculations

    • Authors: Piotr Niemiec, Aleksandra Anioł
      Pages: 30 - 40
      Abstract: The subject of this research is the characterization of the activation process of the oxygen molecule on solvated selected transition metals (3d). In this study , using the Density Functional Theory, quantum-mechanical calculations were made, the purpose of which was to characterize the electronic structure of water and acetonitrile six-coordinated complexes with general formulas [TM(H2O)6]n+ and [TM(CH3CN)6]n+ and complexes with adsorbed at the metal center with an oxygen molecule ([TM(H2O)5-O2]n+ and [TM(CH3CN)5-O2]n+). The calculations were made using transition metal ions from the fourth period of periodic table: TM = Co2+, Fe2+, Mn2+, Ni2+, Zn2+, Cu2+ and Cr3+.
      PubDate: 2023-12-21
      DOI: 10.55225/sti.494
      Issue No: Vol. 17, No. 1-2 (2023)
       
  • Monitoring a metabolic profile of wheat by using FTIR spectroscopy and
           chemometric methods — concept studies

    • Authors: Aleksandra Borek-Dorosz, Rafał Kurczab
      Pages: 41 - 75
      Abstract: Changes in plants under the influence of a variety of chemical and physical factors are reflected in metabolomic changes. To date, there are very few methods that would allow studying metabolic changes occurring in single cells. Spectroscopic methods especially combined with the chemometrics methods are a very good tool to investigate such changes in metabolomics. Tracking changes in plants is of particular importance in industry, especially when studying how the use of fertilizers affects plants. In this paper, we present preliminary research as
      a concept of proof to examine whether the use of FTIR (Fourier transform infrared spectroscopy) helps to monitor the changes in the metabolomic profile of the plants. For preliminary research, four species of cereals and cuckooflower were used. In this step, it was possible to verify the differences in metabolites that are produced by plants belonging to different families. Then one species of grain was selected and subjected to eleven different physical and chemical factors. Next, the research was expanded to determine the optimal concentration of hydrogen peroxide. FTIR spectra of leaves and extracts of the plants were obtained for all experimental groups and then analyzed with the use of chemometric methods: HCA (hierarchical component analysis) and PCA (Principal component analysis). Those methods were used to help in the interpretation of metabolic changes resulting in the plant in response to external factors.
      PubDate: 2023-09-15
      DOI: 10.55225/sti.493
      Issue No: Vol. 17, No. 1-2 (2023)
       
  • The lightweight composite material design for automotive industry

    • Authors: Katarzyna Suchorowiec, Piotr Szatkowski, Ewa Szczepanik, Rafał Twaróg, Michał Kisilewicz, Jacek Gralewski
      Pages: 76 - 84
      Abstract: The article presents the concept of a glass fiber reinforced composite in an epoxy matrix that can be used in a motorcycle frame. Motorcycle frames types enabling the composites usage were analyzed. Composite material samples with different glass fibers orientations were produced using the pin method. The manufactured composite material was subjected to physicochemical tests to determine basic strength properties, density, work of destruction, and microscopic observation was carried out.
      PubDate: 2023-12-21
      DOI: 10.55225/sti.508
      Issue No: Vol. 17, No. 1-2 (2023)
       
 
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  Subjects -> SCIENCES: COMPREHENSIVE WORKS (Total: 374 journals)
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