Bio and Environmental Physics
Bioloogiliselt oluliste molekulide ja molekulaarkomplekside füüsikalised uuringud (juhib prof Arvi Freiberg)
Uuritakse kollektiivsete kvantergastuste iseärasusi nanoskoopilistes biomolekulaarkompleksides, ribosoomi toimemehhanisme ning molekulidevahelistest interaktsioonidest mõjustatud molekulaarkomplekside spektrite barokromismi. Vähemalt osa mõõtmisi (sh kõrgetel rõhkudel) on plaanis teha ainumolekulide peal. Ainumolekulidel saadud tulemused iseloomustavad konkreetset molekuli ja on vabad molekulide lausmõõtmisega kaasnevast parameetrite keskmistamisest. Teema metoodiliseks eripäraks on samuti ülikiire ajalise lahutusega spektroskoopia, kõrglahutusspektroskoopia, kõrgete rõhkude spektroskoopia ning molekulaardünaamiliste ja kvantkeemiliste arvutuslike meetodite koosrakendamine biofüüsikalistes uuringutes. Planeeritud töid täidetakse tihedas koostöös lisaks Prof. J. Remme töörühmale veel mitme objekte valmistava või teoreetilist tuge pakkuva välismaise uurimisgrupiga (CEA Saclay, Jyväskylä Ülikool, Lundi Ülikool, Madridi Sõltumatu Ülikool, Pariisi XI Ülikool, Sheffieldi Ülikool jt).
RESEARCH IN ENVIROMENTAL PHYSICS
Development of the numerical weather prediction towards forecasting of atmospheric environment
(led by prof. Rein Rõõm)
- The aim of the research is to develop a new numerical model of atmospheric dynamics, taking into account the active role of aerosol in forming of weather and climatie, and implementation of that model in weather prediction for Estonia and Northern Europe, and in modelling of global climate change.
- The essence of development is to switch the global aerosol field into the high-resolution atmospheric dynamics such way that (1) the feedback of aerosol to the short-wave radiation balance, cloud formation and dynamics of precipitation is taken into account and (2) the aerosol life cycle in the atmosphere is modelled, depending on meteorological fields and parameters like distributions of wind, water vapour, boundary-layer turbulence and condition of the underlying surface.
- An important priority of the project is to implement the model in the operational weather forecast in the Estonian Institute of Meteorology and Hydrology.
- The staff on the theme includes 8 highly skilled researchers and 7 post-graduate students. They possess up-to-date computing instrumentation, including super- and cluster computers.
Generation of nanometer particles and formation of aerosol particle size distribution in weakly ionized atmospheric environment (Principal investigator Dr. Urmas Hõrrak)
Generation of nanoparticles and evolution of the size distribution of atmospheric aerosol particles are studied in the research project. Aerosols and greenhouse gases are essential climate factors of an equal importance, and the study of these factors has become a priority of present-day science. A significant part of the research deals with the generation of aerosol particles from gases via gas-cluster-particle conversion process, especially with the bursts of nanoparticles generation in the atmosphere. The main goal of the study is to establish how the ionization of atmospheric air affects the generation and size distribution of clusters and aerosol particles in various atmospheric conditions depending on the meteorological situation and air pollution. The results should improve the knowledge basis necessary for modeling and forecasting the environmental and health effects of air pollution. The nucleation theory is refined by combining the thermodynamic model and chemical kinetic model of cluster ion evolution. New fundamental results are expected especially for the particle diameter range of 1−3 nm, in which neither the methods of chemical kinetics nor the thermodynamics are perfect. The methods and equipment for the measurement of aerosol size distribution and air ion mobility distribution are developed in experimental investigations. Refinement of the calibration methods of mobility spectrometers is under especial attention. The experimental-observational and the theoretical studies are carried out in close cooperation with the aerosol research team of the University of Helsinki, supervised by Prof. Markku Kulmala. 12 highly qualified researchers and 6 doctoral students are engaged in the study at the University of Tartu.
Environmental radioactivity research at the Laboratory of Nuclear Spectroscopy Institute of Physics, University of Tartu
Radioactivity in the environment and the resulting radiation doses are, besides a national monitoring programme, objects of scientific research in all neighbouring states and cannot be neglected in Estonia as well. This is an obligation by international agreements, EURATOM treaty and corresponding legal acts, but there is also the need to provide professional information, to measure the environmental radioactivity and interpret the monitoring results, to evaluate current situation and make prognoses for future developments in the field of radiation protection, in cases of emergencies, etc. Research activities at the Institute of Physics of the University of Tartu were initiated by the researchers of the laboratory in the early 1990s.
Main research is focused on the following topics:
Environmental radioactivity research in Estonia for obtaining information about
a) transport and migration of natural and artificial radionuclides in the soil, air and water;
b) radioecological pathways of radionuclides and the formation of irradiation dose in radioactive waste management and impact sources from energy production.
Development and implementation of gamma-spectrometry and methods for numerical modelling, including:
a) low-energy high-purity Ge (HPGe) gamma-spectrometry, validating quality measures for quantitative analysis of environmental samples through routine international proficiency tests practice;
b) transport models of radionuclides and radioecological models of radionuclide pathways in the air, water and soil;
c) gamma-radiation resonance forward-scattering models of ultra fine interactions.
Development of analysis methods for alpha- and beta-radiation detection in environmental applications.