Numerical and experimental investigation of three-dimensional flow in extrusion dies

The univariant element, Q₁ P₀, and the multivariant elements, QP₀ and R P₀, are compared for the numerical simulation of the flow in extrusion dies. The pressure distribution obtained by using the Q₁ P₀ element was found to be afflicted with the checkerboard pressure mode. On the other hand, the multivariant elements, Q P₀ and R P₀, gave accurate and physically reasonable velocity and pressure distributions. The computed values of the pressure drop across extrusion dies matched well with the pressure drop determined experimentally.     

Sustainability assessment of the energy projects implementation in regional scale

The concept of sustainable energy development cannot be separated from the understanding of additional positive socio-economic effect of sustainable energy projects (energy efficiency measures, use of renewable energy sources). Implementation of sustainable energy projects has positive impact on security of energy supply, provides financial economies and improved comfort and has multiplier effect for new jobs, involving small and medium size enterprises. Therefore integration of sustainable energy projects into regional development process may create external positive effect concerning increased energy security and other regional development goals (reduction of unemployment, reduction of environmental impact, etc.). The examples of EU-15 countries implementing their sustainable energy development and climate change mitigation policies on local level can be successfully applied in Lithuania. The aim of the article is to discuss methodological problems related with integration of sustainable energy projects into regional development procedures and provide guidelines, ensuring that energy elements may compile integral uniformity in terms of regional goals.     

Investigation on a new silver photoimageable conductor

A new thick film photoimageable silver paste of improved properties has been elaborated. The paste is less sensitive to the visible light. Certain disadvantages of most commercially available materials, such as necessity of operating with the paste in the room illuminating with yellow, green or red light has been eliminated. Further improvement of conductive silver pastes to enable reducing lines width down to 10 μm has been done.     

Sustainable energy in Baltic States

Integration of New Member States to the European Union has created a new situation in the frame of implementation of the Lisbon strategy and EU Sustainable Development. The closure of Ignalina NPP is the biggest challenge to the energy sector development of the Baltic States. The Baltic States have quite limited own energy resources and in the Accession agreement with the EU Lithuania, Latvia and Estonia have verified their targets to increase the share of electricity produced from renewable energy sources (RES-E) by the year 2010. A wider use of renewable energy and increase of energy efficiency can make a valuable contribution to meeting the targets of sustainable development. The article presents a detailed overview of the present policies and measures implemented in the Baltic States, aiming to support the use of RES and the increase of energy efficiency. The review of possibilities to use the EU Structural Funds (SF) for the implementation of sustainable energy projects in the Baltic States was performed.The use of regional social–economic–environmental indicators is the main key to integrate sustainable energy development at the program deployment level. The indicators to be used should describe the contribution of energy programs to the sustainable development, medium- and long-term trends and inter-relationship between them and the typical energy indicators (saved toe, improved energy efficiency, percentage of RES). Municipalities may play a considerable role by promoting sustainable energy since local authorities are fulfilling their functions in the energy sector via a number of roles. The Netherlands’ example shows that municipalities may act as facilitators by implementing national environmental policy and increasing energy efficiency in an integral part of these activities. The guidelines for Lithuanian local sustainable energy development using the SF co-financing have been presented.     

A new photoimageable platinum conductor

A new thick-film photoimageable platinum paste has been elaborated. The paste is less sensitive to the visible light. The resolution line/space 20/30 μm is achievable. The application of the elaborated paste to produce heaters is demonstrated. The stability of the heaters has been evaluated.     

The use of constrained and unconstrained optimization models in gradation design of hot mix asphalt mixture

The paper describes the essential differences in determining optimal gradation of hot mix asphalt (HMA) mixture used in road building at the stages of its selection, initial design and production, and presents the respective algorithms. The models of constrained and unconstrained non-linear optimization are developed, allowing us to choose the best HMA mixture gradation based on mineral materials, whose gradation is known, when the total percent passing of HMA mixture aggregates is considered to be equally important for all sieves, or when preference is given to some of the sieves. A new linear optimization problem best suited for practical use due to its simplicity is offered. By introducing weight coefficients for the dimensions of the objective function of the model, zero deviations of the percent passing of HMA mixture aggregates from their standard values may be easily obtained, based on the preferences set. All mineral materials (aggregates) obtained at batch-type asphalt mixing plants should be used for HMA production. Their total mass is equal to unity, while the mass of each material is a positive quantity, and a predetermined relationship between the masses of imported filler and the reclaimed dust is used. In the experimental part of the work, the problems were solved using the SAS system.