«ANNUAL REPORT Riga 2012 Annual Report 2011, Institute of Solid State Physics, University of Latvia. Editor: A.Krumins. Composed matter: A.Muratova. ...»
3. ERDF project Nr.2010/0243/2DP/126.96.36.199.0/10/APIA/VIAA/156, subproject “Vacuum coatings for solar energy collector” (2011-2013).
4. ERDF project „Development of innovation technology for producing of solar silicon using electron-beam technology” Nr.2010/0245/2DP/188.8.131.52.0/10/APIA/VIAA/114 (2010-2013)..
5. ERDF project "Innovative glass coatings" No.
7. National Research Program “Innovative multifunctional materials, signal processing and informatic technologies -IMIS”, task No. 1.21 – Investigation functionalization of glass fiber fabrics.
8. National Research Program “Energy and Environment”, Project No.4 & No.6 “Research of methods for hydrogen production, storage and energy release, and development of prototypes for application in national economy”
9. Cooperation project of. Latvian Council of Science SP 10.0032 “Development of research and technology potential for elaboration of new and nanostructured materials and related applications”, subproject No.1.4. “Functional caoatings, processes and technologies for modification physicochemical properties of materials”
10. Cooperation project of. Latvian Council of Science SP 10.0040 “Investigation of Latvian renewable raw materials – flax and hemp products for development of innovative technologies and new functional materials”, subproject “Funcionalization flax and hemp fibers with metal an metal oxides coatings”.
11. Grant from Latvian Council of Science Nr.09.1580 "Structure of nano-oxide materials and self-organization in stochastic media.
12. Grant from Latvian Council of Science No. 09.1192 “Research of properties and structure of nanosize composite materials for hydrogen storage and electrodes for water electrolysis”
13. Grant from Latvian Council of Science No. 09.1195 “Research and development of proton conducting PEEK polymer and composite membranes and catalysts for use in direct methanol and hydrogen fuel cells”
14. Grant from Investment and Development Agency of Latvia “Development and pilotproject implementation on eco-effective transport system in Latvia”
15. Grant from Riga City Council and SwedBank “Hydrogen based heater for vehicle salon and engine”
16. Grant from Student Council of University of Latvia “Synthesis and properties of TiO2 oriented nanotube layer”
1. MNT ERA-NET Matera Project "Functional materials for resistive switching memories" (FMRSM) (2009-2011).
2. EFDA Fusion Technology task TW5-TTBB-006-D08 „Assessment of the effects of magnetic field, radiation and temperature on the tritium release from beryllium pebbles.
Identification of chemical forms of tritium accumulated in the irradiated Be pebbles.” (Principal investigator: Dr.chem. Gunta Ķizāne).
3. The European joint undertaking “Fusion for Energy” (F4E) work programme 2009 “Test Blanket Modules”. Contract reference: F4E-2009-GRT-030 Action 3. Coordinator at the University of Latvia: Gunta Kizane.
4. JET Fusion Technology programme. Field: Plasma facing components. Task No.: JW9-FTTask title: “Analysis of tritium distribution in plasma facing components”. Deliverable D3 “The tritium release from untreated plasma exposed tiles under the simultaneous action of temperature, radiation and magnetic field”. Principal investigator: Dr.chem. Gunta Ķizāne.
Didactic work at the University of Latvia
1. Course Fizi5028 "Structure and Description of Nanomaterials" at the Latvian University (A.Kuzmin).
2.Course Fizi7009 „Solid State Structure” at the Latvian University (A.Kuzmin).
3. Supervision (A.Lusis) of student Rims Janeliukštis (Faculty of Physics and mathemativs, University of Latvia) for a bachelor’s thesis on the topic “Modification of physical and chemical properties of glass fibers“, the bachelor’s thesis was defended in June 2011.
4. Supervision (A.Lusis) of student Janis Zandersons (Faculty of Physics and mathematics, University of Latvia) for a bachelor’s thesis on the topic “Methods and processes for functionalization textile fibers“, the bachelor’s thesis was defended in June 2011
5. Supervision of student Andris Matīss (Faculty of Chemistry, University of Latvia) for a bachelor’s thesis on the topic “Tritium release from neutron irradiated beryllium pebbles under action of temperature”, the bachelor’s thesis was defended in June 2011.
The WOCl4 structure consists of pyramidal WOCl4 units which are linked by linear asymmetric O- - - W----O bridges to polymeric (WOCl4 )n chains. The vibrational modes of WOCl4 have been investigated. Calculations have been performed by using hybrid exchange density functional theory to determine equilibrium geometries and phonon frequencies. The Grimme dispersion correction for energy and gradient has been used in combination with B3LYP functional. The CRYSTAL09 computer code was used.
Metal coatings are widely used for functionalization of fabrics for different technical applications. The fabrics are porous medium versus plastic films, foils or sheets. The porous media usually adsorbs various chemical substances from the environment. One of them is water therefore content of moisture in fabrics have to be controlled before functionalization.
The electrical impedance spectroscopy is good method to study water in fabrics. The impedance spectra of system M/F/M are complicate due to heterogeneous constitution of system. There are problems with interpretation impedance data. There is need for appropriate physical models too. One way to solve the problem is to find relations between the systems M/F/M constitution, pore and metal type and the content of moisture.
In present work both sides of glass (GF) and flax (FF) fabrics were coated with metal (M = Ni, Cu or Al) and electrical impedance spectra of the systems M/F/M were studied. The leaching of glass fibers have been used to obtained porous fibers and fabrics on the micro and nano level. The flax fibers and fabrics are natural porous. Fabrics were coated with metal (Ni, Cu or Al) by DC magnetron sputtering in 100% Ar atmosphere.
Regardless of whether impedance |Z| value is big or small for the freshly made sample the absorption of water can reduce or increase the |Z| values. The deposited metal particles in porous surface formed electronically conducting channels with some percolation threshold, which could be changed by concentration and size of metal particles and water content. H2O molecules separate metal particles and provide ionic conductivity.Further more detailed studies for functionalization of nanostructured technical glass fibers and fabrics with metal coatings are required to explain how adsorbed H2O change impedance spectra. Hierarchical pore structures on macro, micro and nano level, from one side, and interpenetrating electronically and ionically conducting networks, from other side, can be used to explain impedance data.
L.Veļķere, R.Janeliukštis, J.Zandersons, J.Balodis, E.Pentjuss, A.Lūsis For the development of new products based on technical textiles, which will be functionalized by vacuum coating technologies, is important test influence of functionalization technology on thermomechanical properties of textile yarns.
For that the system for test of thermomechanical properties of glass, flax and hemp yarns was build on instrument “Mecmesin model “MultiTest 1-i” with software EMPEROR” base. The temperature of furnace (Fig. 2) is ccontroled with Fuji Electric Micro-controller PXR3.
• The long of yarn or test have been 20 cm.
• Load/force up to 250 N
• Maximal tension speed 500 mm/s Temperature 20 – 700 0C.
Titanium dioxide thin films have been extensively studied because of their excellent properties for photocatalysis, gas sensors, ultrafiltration membranes, self-cleaning coatings, solar cells and photovoltaic applications. Many efforts have been made to improve their properties by preparing porous films with high surface area. There are a wide variety of preparation methods for TiO2 thin films, e.g. sol-gel, doctor blade, spin coating, chemical vapor and sputter deposition. In this study nanocrystalline TiO2 thin films have been prepared by sol-electrophoretic deposition process.
The first step was the preparation of TiO2 sol. Titanium tetrabutoxide (TTB) was used as a precursor, hydrochloric acid as a catalyst for the peptization and deionized water as a dispersion media. A water-acid mixture was stabilized at 50 °C with continuous stirring. An appropriate amount of TTB was added next forming the white precipitate that gradually peptized forming a clear sol.
For the electrophoresis growth, the Pt anode and cathode are placed parallel in TiO2 sol with a distance 1 cm in between. The cathodes used were metallic Cu and Ti, thin Pt layer on silicon, transparent indium tin oxide (ITO) on glass. A constant voltage of 0.6 – 1V was applied by a dc power supply between the electrodes and held for 1 – 3 h. The as-deposited thin films were first dried at 100 °C for 24 h and then heated at a rate of 10 °C/min and were finally annealed at 500 °C for 2 h.
Obtained TiO2 thin films were characterized by phase composition, morphology and their microstructures using X-ray diffraction, Raman spectroscopy, as well as transmission electron microscopy and scanning electron microscopy.
This work was financially supported by European Regional Development Fund project No.2010/0243/2DP/184.108.40.206.0/10/APIA/VIAA/156.
RESEARCH AND DEVELOPMENT OF MATERIALS AND DEVICES FOR
HYDROGEN ENERGY TECHNOLOGIES
Using inductive voltage pulses to power electrolysis cell allows reducing the total power necessary for electrolysis . A great advantage of the proposed pulse electrolysis is that the charging of electrolytic cell lasts for a relatively shorter period than the following discharge using stored energy. Square pulses from the generator were applied to the field transistor connected in series with the DC power source. The end front of rectangular signal in the secondary winding of bifilarly wound transformer induced very sharp inductive pulse with high amplitude and opposite polarity with respect to applied voltage. Pulse of induced reverse voltage (the width 1 microsecond, amplitude 3-300 V) is passed through the blocking diode to the electrolytic cell. Results showed that the current pulse direction changes from negative to positive with the increasing concentration of electrolyte. The authors believe that such kinetics can occur when the electrochemical charging process in the cell is separated from a Faradic charge transfer process. At applying a sharp pulse the water electrolysis cell behaves as a capacity with a high Q-factor, while the Faradic discharge manifests itself by a discharge tail, when the power stored during cell charging in short pulse is used.
Our research with biohydrogen production is directed to find and test applicable bacterial isolates and different local substrates for hydrogen production. Experimental reactor test-system is built with separate glass chambers for simultaneous measurements of gases in liquid phase (hydrogen and oxygen) and gas phase (hydrogen, methane, carbon dioxide) to determine hydrogen production rate in fermentation process. Parallel gas analysis is made with the RGAPro-100 mass-spectrometer connected to the experimental test-system.
Experiments were made with different isolates: Aneurinibacillus aneurinilyticus, Clostridium sporogenes, Enterobacter asburiae, Enterobacter cloacae, Eubacterium limosum, Kluyvera ascorbata, Paenibacillus pabuli (isolates from Microbial Strain Collection of Latvia), E.coli BW25113 hyaB hybC hycA fdoG frdC ldhA aceE::kan (from prof. T.K.Wood, USA). Glucose, lactose and glycerol were used as substrates, concentration varied between 15 to 240 mM.
After fermentation processes following results were obtained in liquid and gaseous phase:
Escherichia coli BW25113 hyaB hybC hycA fdoG frdC ldhA aceE::kan produced hydrogen with rate 3 mmol/L/h, using 30mM glucose as substrate and 0, 04 mmol/L/h, using 60 mM lactose as substrate in gaseous phase. Clostridium sporogenes produced 1,5 mmol/L/h hydrogen in gaseous phase and 1,42 mmol/L/h hydrogen in liquid phase using 240 mM glycerol as substrate.
For successful hydrogen storage purposes the great concern is the development of materials, including zeolites, in which hydrogen might be stored without high energy consumption. Our research is focused on hydrogen adsorption facilitated with spillover from catalyst sites porous oxide substrate. The spill-over of hydrogen involves a transfer of electrons to acceptors within the support; this process modifies the chemical nature of the support and can also activate a previously inactive material and/or induce subsequent hydrogen physisorption. Sievert type and thermogravimetric measurements of zeolite/Pd and glass/metal hydride (MH) samples proved that the created composite material absorbs more hydrogen per weigh unit than both components separately. Unexpected observation was the deeper hydrogen absorption is induced in metal alloy, due contact between metal alloy and oxide material substrate – not only α and β hydride phases are reached, but also phase.
Using the method of cooling the zeolite samples in the hydrogen atmosphere, it is found that values of 3-5 wt% of stored hydrogen can be easily achieved. We are looking for an explanation of this effect.