Motivation letter

Please write a brief motivation letter (in English, maximum of 6000 characters with spaces) based on the following points:

1. Why are you interested in this PhD project, explain your choice.
2. What is your previous experience in this field? Explain how your educational and professional background relates to the project you are applying to.
3. What are the analytical/scientific methods you have practiced.
4. Describe briefly the methods and main results of your MSc thesis.
5. Decribe your earlier research activities, including research publications and conference presentations, if available.
Assessment criteria for motivation letter:

- motivation and argumentation of skills and the choice of the project
- relevant study and work experience and other relevant activities (publications, project management etc.) as required to present in the motivation letter.

Interview

The applicant must describe the wider scientific background of the doctoral project and possible applicability of the results, also their motivation to be admitted to PhD studies with particular project. Only applicants whose motivation letter is assessed positively will be invited to the interview (minimum positive result is 35 points out of 50).

The entrance interview is used to assess the following:

- knowledge of the wider scientific background of the project and possible application of the expected results
- applicant’s motivation to pursue doctoral studies in the relevant field of science and to work in this field
- wider analytical and generalization skills regarding the research and study topics.

International applicants who cannot be present at the interview in Tartu, may conduct an online interview. Applicants will be informed of their interview date and time by the respective faculty.

Both the motivation letter and entrance interview are assessed on a scale of 0 to 50 points, minimum positive score is at least 35 points. To be invited to an interview, the applicant must earn at least 35 points for the motivation letter.

Supervisor: Kalle Kirismäe

Mineral demand is rising sharply, particularly for rare earth elements, battery metals, and non-ferrous metals. Estonia’s geological exploration has mainly focused on sedimentary resources, while its crystalline basement remains underexplored due to thick sedimentary cover, necessitating advanced geophysical and geochemical approaches. This project aims to evaluate the effectiveness of integrating classical and machine learning algorithms in analyzing the Estonian crystalline basement geochemical datasets to establish a replicable model applicable to various sedimentary platform settings where targeted exploration for critical metals in buried crystalline basement rocks is challenging.

Supervisors: Alar Jänes, Maarja Paalo, Enn Lust

Following a cost-effective synthesis method, hard carbon will be prepared using precursors such as wood, peat, straw, and old tires. Synthesis steps such as acid-base precursor treatment, doping with heteroatoms, and high-temperature pyrolysis will be optimized.

As a baseline cathode material, a P2-type layered oxide, potentially Na_2/3Ni_1/4Mn_3/4O₂, will be used. Wet-chemical processes and surface-based reactions will be developed to apply protective ceramic coatings onto the layered metal oxides.

Appropriate binders that meet the criteria for both aqueous and dry processability will be selected for the anode and cathode coatings. The integration of additives into the dry coating process will also be investigated. Electrodes will be fabricated using electrostatic dry-spraying techniques or conventional rolling methods to fine-tune coating thickness and porosity. Various dry powder mixing strategies will be evaluated to ensure optimal dispersion of the binder and conductive agents.

To better understand the limiting factors in electrode performance and degradation mechanisms, advanced characterization methods such as XPS, SEM-FIB/EDX, TEM, and TOF-SIMS will be employed on both new and aged electrodes.

Performance targets and corresponding testing protocols will be established, and the full cells will be designed and tested accordingly. The final pouch cells will be assembled and evaluated for capacity, cycle efficiency, capacity retention, rate capability, cycle life, and energy density.

Supervisors: Siim Salmar, Siobhan O. Matthews (SCF Processing Ltd, Iirimaa)

Mechanical processing of pine wood in Estonia is world class, an example of which is Barrus
AS, a leading European manufacturer of pine finger-jointing and glued laminated timber
components in South-East Estonia, targeting door and window manufacturers. However, the
production process leaves over 200 000 m3 of residues per year (over 10 million m3 in Estonia
and the Baltics combined), which are mainly used in wood pellet production for cheap energy.
Pine wood is rich in extractive compounds such as lipids, resin acids, lignols, and more, which
makes pine biomass a non-favourable feedstock for use in biorefining technologies. The
Laboratory of Wood Chemistry and Bioprocessing at the University of Tartu has planned a
Ph.D. project in cooperation with Barrus AS, which focuses on the development of novel
refining technologies for pine wood with the aim of finding the most optimal technological
and economic solutions for wood biorefining.
The use of supercritical fluids for the extraction of bioactive substances has proven itself in
the pharmaceutical and food industries. In this project, we are collaborating with one of
the world's leading developers of supercritical fluid technologies, SCF Processing Ltd., to find
ways of pre-treating pine wood for the recovery of extractive compounds. The project will
test different ways of using supercritical fluids, resulting in the necessary findings to upscale
to a pilot reactor design at the University of Tartu. Valuable applications for pine wood
extractive components and lignocellulosic biomass will be analysed and found to provide
input for integrated pine wood biorefining.

Supervisors: Veikko Pentti Linko, Olavi Reinsalu, Sven Oras

The project aims to improve the genetic engineering of living organisms by harnessing well-established but novel DNA/RNA nanotechnology. The research will provide custom mRNA and gene-encoding DNA nanostructures for controllable translation and expression in mammalian cells. The efficiency and functionality of the origami assemblies in complex biological contexts will be further boosted by encapsulating them using modular molecular coatings. The tools developed in this project will open new avenues for scientific and bionanotechnological exploration, enabling multiple diverse applications such as mRNA vaccines and gene editing. These advancements will further pave the way for meeting key global sustainability challenges related to health, food, and the environment.