Now showing 1 - 5 of 5
  • Publication
    Mechanical and electrical properties of the solid sapropel
    (2015) ;
    Josef Timmerberg
    ;
    ;
    Paul Beckmann
    ;
    Valentina Popa
    ;
    Regina Wagner
    In this paper are explored the mechanical (ultimate compression strength, ultimate strain, Young’s modulus, hardness) and the electrical (relative permittivity, specific electrical resistance, quality factor, their dependence on the electric field frequency in the range till 1MHz) properties of the solid sapropel. For the researches are used samples from the solid, monolith sapropel (obtained in the drying process) and samples from the sapropel powder that are pressed with a different force; before the measurements, a part of these samples were heated. There is explored the dependence of the relative permittivity on temperature. Are explored the methods for the forming of the products from the solid sapropel powder.
    Scopus© Citations 1
  • Publication
    EFFECT OF HEAT TREATMENT ON ELECTRICAL AND MECHANICAL PROPERTIES OF THE SOLID SAPROPEL
    (2017) ; ;
    Rene Castro
    ;
    Vladimir Solovyev
    ;
    Josef Timmerberg
    ;
    Alexander Cvetkov
    ;
    Sergey Gango
    ;
    Angelika Borkenstein
    ;
    Paul Beckmann
    ;
    Helmut Schütte
    ;
    Nikolai Puchkov
    ;
    Sergey Trifonov
    In this work changes of electrical and mechanical properties (hardness) of the solid sapropel after its heat treatment were researched. Changes of real and imaginary parts of dielectric permittivity, dielectric losses and specific electrical resistance depending on electrical field frequency in the range 0.01Hz- 1MHz were observed. Temperature dependences of AC (at 1 kHz) and DC electrical conductivity were studied. Chemical sample composition, IR spectra and structure of the solid sapropel were investigated. Heat treatment has a noticeable effect on the electrical characteristics of solid sapropel due to the strong influence of water on the charge transfer in this complex material. Charge transfer occurs predominantly due to ion migration and demonstrates strong dependence upon hydration - dehydration processes. After the heat treatment of the solid sapropel at the temperature of 1000C its hardness doesn’t change. If the sample of the solid sapropel is subjected to 20 min heat treatment at the temperature of 1500C, its hardness decreases by 5.4%, the number of C=C bonds decreases by 6.3±0.1%, the number of C=N bonds decreases by 2.2±0.1%, the number of C-C bonds decreases by 1,7±0.1%, the number of C-H bonds increases by 18.5±0.3%. It shows that in the temperature range 100-1500C destructive processes of the solid sapropel start, although visually (with optical microscope and with SEM) changes of structure are impossible to observe yet.
    Scopus© Citations 2
  • Publication
    Research Into Biological Characterictics of Dried Sapropel
    (2015) ;
    Jūlija Grebeža
    ;
    Microbiological characteristics of dried sapropel of Lake Rušona and Lake Ubagova and concrete containing sapropel and hemp sheaves (Ubagova Lake) have been studied. The antimicrobial activity was studied by the Staphylococcus aureus  ATCC 25923, Salmonella enteritidis ATCC 13076, Enterococcus faecalis  ATCC 29212, Bacillus cereus  ATCC 10876, Escherichia coli ATCC 25922, Candida albicans ATCC 10231. Antibacterial activity on reference test cultures is stated in Rušona Lake sample before treatment with UV rays. Antibacterial activity is not stated in Ubagova Lake sapropel sample. 20 minutes’ long UV ray treatment is not long enough to prevent the growth of sapropel materials. Both Rušona Lake and Ubagova Lake samples contain microorganisms that start growing and intensively reproducing in favourable conditions. When in contact with humidity, at the temperature from 18 to 37± 1C, mold colonies form on concrete containing sapropel and hemp sheaves, for this reason this material should not get in contact with humidity when used in construction.
    Scopus© Citations 4
  • Publication
    Lake blue clay - sapropel - flax shive briquettes for water absorption and desorption
    Article Latvian lakes are rich in sapropel sediments and below the sapropel layer there is another valuable natural resource, namely blue clay. Flax shives are formed in large quantities as a waste in flax processing factories. The problem involves processing and rational use of these reso urces. The paper studies the obtaining of briquettes from flax shives using sapropel and lake clay as a binding material. Briquettes are intended for use in cases when problems with regular plant watering occur. For example, provision of plants with water in greenhouses, indoor spaces for a long period of time without human presence. Briquettes are placed into the soil next to the plant roots. Briquettes are initially moistened and absorb a significant amount of water (moisture content to be expressed in co mparison to the sample's dry weight 250 – 380%). The presence of clay in them contributes to slow drying of briquettes and provides a long lasting supply of moisture to the plant roots. The paper deals with the issues of the optimal composition of components and the amount of pressure for the production of briquettes, as well as water absorption and desorption properties of briquettes. The aim of the study is to develop a production method of clay – sapropel – flax shive briquettes with good water absorption and desorption properties.
  • Publication
    IMPACT OF LASER ON MICROORGANISMS IN THE DIGESTATE
    At the biogas plant total of 40 digestate samples have been collected and investigated. The microbiological composition of digestate has been analysed before and after laser processing with wavelength λ 445 nm with power 2 - 4 W. Salmonella spp. has not been stated in any of the samples, Escherichia coli and Enterococcus spp. amount does not correspond Eiropean Union regulation R142/2011 requirements in any of the investigated samples; Staphylococcus aureus has been stated in 24 samples out of 40. By decreasing laser scanning speed and increasing power, the total number of microorganism colonies in digestate has decreased.