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  • Publication
    Content of Heavy Metals in the Reed Canarygrass (Phalaris Arundinacea L.) in the First Year of Harvest
    (2011-03-05)
    Rasma Platace
    ;
    Aleksandrs Adamovics
    ;
    One of the major factors in achieving more biofuel is the amount of crop yield, but that is not synonymous with the yield quality. Plants are contaminated by heavy metals not only through the soil, but also from atmospheric pollution. The aim of this research was to establish the amount of heavy metals in the dry matter of reed canarygrass (Phalaris arundinacea L.). The Marathon variety of reed canarygrass was studied with two sowing periods and four Nfertilizer rate applications. The concentration level of arsenic (As), cadmium (Cd), lead (Pb) and titanium (Ti) in the samples of reed canarygrass were analysed with the coupled plasma optical emission spectrometer Perkin Elmer 2100 DV. The samples of reed canarygrass taken in April had a greater concentration of As, Cd, Pb, which means that the plants absorb the heavy metals also from the snow covering. The first year yield of reed canarygrass established a fundamental negative correlation between the amount of As, Cd, Pb and the ash content. The samples taken in April have a greater heavy metal contamination, than the samples taken in October. The sowing period fundamentally affected the concentration of lead in reed canarygrass samples, but the level of N-fertilizer rate application affected the amount of cadmium and arsenic.
  • Publication
    Hemp (Cannabis sativa L.) as an Environmentally Friendly Energyplant
    (2011-03-05) ;
    Aleksandrs Adamovics
    Hemp (Cannabis sativa L.) as an Environmentally Friendly Energyplant. Hemp is suitable as a renewable energy resource. The aim of this study was to clarify local hemp's (Cannabis sativa L.) possibilities for energy use. Arsenic (As), cadmium (Cd), lead (Pb) and titanium (Ti) presence in hemp was determined using an inductively coupled plasma optical emission spectrometer Optima 2100 DV. If there were increased N fertilizer rates, there were increased hemp ‘Pūriņi’ seeds and shive yield increases, but the oil content was reduced. Arsenic content was higher in the shives than in the stems with fibre. The ash content depends on non-organic substances which the plants absorb during the vegetation season. The lignin content depends on several factors: plant parts, and the N fertilizer rate. The unexplored factors have a great effect on the ash and lignin content. Hemp is suitable for cultivation and for bio-energy production in the agro-climatic conditions in Latvia.
  • Publication
    Gaisa enerģētiskā stāvokļa ietekme uz pilsētu infrastruktūru
    (2010)
    Skromulis, A
    ;
    Grigorjeva, J
    Rakstā aktualizēta atmosfēras gaisa kvalitātes problēma, īsumā raksturotas gaisu piesārņojošās ķīmiskās, mehāniskās un enerģētiskās komponentes, īpašu uzmanību pievēršot gaisa enerģētiskajam stāvoklim kā savdabīgam gaisa kvalitātes indikatoram. Rakstā sniegts ieskats pozitīvo un negatīvo aerojonu klasifikācijā un struktūrā. Īsumā izklāstīta gaisa jonizācijas teorijas būtība un jonizācijas ietekme uz dabas vides abiotisko un biotisko komponenti, īpašu uzmanību pievēršot pozitīvo un negatīvo vieglo aerojonu fizioloģiskajai ietekmei uz cilvēka organismu. Tajā atspoguļoti Rēzeknes pilsētas dažādos mikrorajonos veiktie vieglo aerojonu koncentrācijas un dažu meteoroloģisko faktoru mērījumi, kas veikti 2009. gada jūlijā – augustā. Analizējot iegūtos datus, izdarīti secinājumi, ka vispārējais gaisa jonizācijas līmenis pilsētā ir vidējs, atklāta vispārēja tendence negatīvo aerojonu koncentrācijai dienas laikā samazināties, bet pozitīvo aerojonu koncentrācijai pēcpusdienā pieaugt. Īsumā raksturots, kā pilsētas infrastruktūra ietekmē gaisa kvalitāti tajā, un sniegti priekšlikumi iespējamai pilsētas tālākai attīstībai.
  • Publication
    WETLAND CHANGE DETECTION USING SENTINEL-2 IN THE PART OF LATVIA
    (2023)
    Andris Skromulis
    ;
    Juris Breidaks
    ;
    Mārtiņš Puķītis
    In the article, the possible impact of changes on wetland were analysed by the semi-supervised classification method of statistical analysis. The Sentinel-2 raw data between two different seasons are combined together. The data preparation is shortly described in the article. Data is clustered with unsupervised method. The article describes a supervised method – how data credibility and classification can be estimated if its reference is poor quality.
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