خيارات البحث
النتائج 1 - 4 من 4
Did the ambient ozone affect forest ecosystems in the Baltic region?
2007
Augustaitis, A., Lithuanian Univ. of Agriculture, Akademija, Kauno reg. (Lithuania)
The presented study aimed to explore the relationships between different indices of ambient ozone (O3) and tree defoliation, radial increment, and specific diversity and abundance of soil micro-arthropods, stream macro-invertebrates, small mammals (mainly rodents) in order to test the hypothesis that changes in the considered objects of forest ecosystem could be related to changes in ambient ozone concentration. The observations have been carried out on 3 integrated monitoring stations located in Aukstaitija (LT-01), Dzukija (LT-02) National Parks (NPs) since 1994, and Zemaitija (LT-03) NP since 1995. The obtained data revealed that only peak ozone concentrations (from 125 to 215 mug mE-3) had significant effect on changes in the considered components of forest biota. Radial increment and crown defoliation of Scots pine, a little lower the diversity of soil microarthropods, and the least diversity of small mammals were found to be the most sensitive to ozone exposure.
اظهر المزيد [+] اقل [-]Experimental research of ozone using in grain drying
2006
Lauva, A. | Palabinskis, J.
Decrease of the consumption of energy resources is possible if grain is actively dry at low air temperatures, which also has a more favourable effect on a single grain. By using the new low-temperature technologies in grain drying, the same effect can be reached as by using grain dryers with high air heating temperatures. One of such technologies could be active drying of the grain layer at low air temperatures in ozone medium. Laboratory experiments show that the carried out moisture from grain is more efficient is active drying is performed using ozonized air. The presence of ozone in grain active drying process increases the amount of carried out moisture. Ozone when decaying to ordinary oxygen creates additional energy, which can be efficiently used in grain drying. As a result, grain drying is accelerated and energy consumption is decreased. Laboratory experiments prove the effectiveness of the presence of ozone in grain active drying process.
اظهر المزيد [+] اقل [-]Evaluating early changes in young tree seedlings under simulated urban environment
2024
Černiauskas, Valentinas | Varnagirytė-Kabašinskienė, Iveta
Urban trees, integral to urban environments, demonstrate intricate responses to atmospheric pollutants like particulate matter (PM), tropospheric ozone (O₃), and carbon dioxide (CO₂). Notably, O₃ induces oxidative stress in leaf tissues, while PM, consisting of fine airborne particles, interacts with urban trees through foliar deposition. This interaction is particularly interesting as tree canopies are highly effective filters, capturing and accumulating PM on their surfaces. The present study focused on silver birch, small-leaved lime, and Norway maple seedlings responses to elevated O₃ and CO₂). With and without PM. Maple seedlings exhibited the highest stem height increment, followed by lime and birch. Elevated O₃ and CO₂ without PM led to substantial height increments for lime and maple. Elevated O₃ and CO₂ without PM increased the total polyphenols in lime and maple leaves but decreased the content of total flavonoids in birch and lime leaves. Our findings underscore the adaptability of lime and maple seedlings to elevated O₃ and CO₂, positioning them as promising species for urban environments in the face of changing climates. Birch, while exhibiting biochemical changes, demonstrated less pronounced growth responses. This studyʼs insights into the intricate interactions between urban trees and multiple pollutants, particularly the species-specific responses, are of significant value for urban planning and environmental management.
اظهر المزيد [+] اقل [-]Flue gas analysis of apple and grey alder wood pellets in a meat smokehouse chamber
2023
Zandbergs, Jānis | Champion, Jordane Jean-Claude | Zeps, Mārtiņš
The use of the smoke released during the wood burning process to prepare food products is a centuries-long tradition, practically all over the world. However, during the combustion process, a group of compounds called polyaromatic hydrocarbons (PAHs) are formed in the flue gases, which are carcinogenic and condense during the smoking process and diffuse into the smoked food product. Therefore, permissible PAH norms have been set for food producers, which significantly complicate the use of wood. In the study, using a gas analyser, we measured the flue gases released during the burning of specially made, apple and grey alder wood pellets, with and without enrichment of the supplied air with ozone. The use of ozone does not ensure a higher burning temperature of pellets, but it stabilizes it – temperature fluctuations are significantly wider using non-ozonised air (697 to 817 and 611 to 817 ℃, respectively). The content of CO2, CO, as well as CH4 and N2O increases significantly in apple wood flue gases using ozonised air, while CH4 increases and N2O decreases in grey alder smoke. Which generally indicates specific reactions with ozone during combustion. Comparing the flue gases released during the burning of apple and grey alder wood pellets, grey alder smoke contains significantly more N2O and CO2 than apple wood pellet flue gases. On the other hand, using ozonised air in the combustion process increases N2O significantly in the flue gas of apple tree pellets compared to white alder.
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