Lietuvoje vykdoma viešojo sektoriaus buhalterinės apskaitos ir finansinės atskaitomybės sistemos reforma, kurios tikslas sudaryti teisines, administracines ir finansines sąlygas visame viešajame sektoriuje pereiti prie apskaitos tvarkymo kaupimo principu, yra aktuali tema viešojo administravimo magistro baigiamajam darbui. Lietuvos viešojo sektoriaus buhalterinės apskaitos ir finansinės atskaitomybės sistema nėra vientisa ir turi eilę trūkumų, reglamentavimas nepakankamas ir neaiškus. Todėl viešojo sektoriaus buhalterinės apskaitos informacija ir finansinė atskaitomybė tampa nenaudinga jų vartotojams, nes nėra tiksli ir teisinga. Pagrindinė ilgalaikio materialiojo turto apskaitos problema, nagrinėjama darbe, ne visas viešojo sektoriaus turtas įtraukiamas į apskaitą ir finansines ataskaitas, o dalis įtraukiama neteisingai. Tyrimo objektas: ilgalaikio materialiojo turto apskaita. Darbo tikslas: išanalizuoti ir įvertinti Lietuvos viešojo sektoriaus ilgalaikio materialiojo turto apskaitą reglamentuojančias nuostatas ir Viešojo sektoriaus apskaitos ir finansinės atskaitomybės standartų reikalavimus, pateikti esminius skirtumus ir pranašumus. Darbe iškeltos hipotezės: viešojo sektoriaus atskaitomybės formose įrašyti turto apskaitos rodikliai, kuriems, pagal nustatytas apskaitos tvarkymo taisykles, negalima sukaupti informacijos, todėl atskaitomybė sudaroma netiksliai; registruojant ilgalaikį materialųjį turtą įsigijimo verte ir periodiškai jį perkainojant, turto apskaita atitiks... [toliau žr. visą tekstą] / The reform of accountancy and financial accountability system of the public sector is being performed in Lithuania, the purpose of which is to create legal, administrative and financial conditions in whole the public sector to turn to account management by principle of accumulation. The Lithuanian accountancy and financial accountability system of public sector isn’t solid and has a line of defects, the regulation is not safisfactory and clear. Therefore, the information of accountancy and financial accountability becomes useless for their customers, because it is not correct and right. The main problem of the long-term material property, which is explored in this work, is the fact that not all the property is included into the accountancy and financial accounts, and a part of it is included wrong. The object of exploration: the accountancy of a long-term material property. The purpose of the work: to analyze and evaluate the rules regulating the accountancy of a long-term material property of the public sector of Lithuania and the requirements concerning the Standards of the accountancy and financial accountability system of the public sector, to provide their essential differences and similarities. The hypotheses raised in the work: the indices of property accountancy written in the forms of accountability of the public sector, for which it is impossible, according to the established rules of accountancy management, to accumulate any information, therefore, the... [to full text]

This dissertation solves the problems with management of capital goods in the company FORMIRA, s.r.o. The dissertation is elaborated from the analysis of present situation in the plant, whereas the heed is oriented to the most important areas, especially the organization and service activity and maintenance of assets. The result of performed analysis is the identification weak points. Proposals are submitted in the second part of the dissertation, in order to solve the problems found by presented analysis. The economical evaluation of the proposals and determinations of assumptions for the application of extended results to the company use is performed at the end of the dissertation.

This thesis is focused on analysis of production facilities utilization and maintenance in the company RAMET C.H.M. a.s. located in Kunovice. In this thesis, there is performed the analysis of present property condition, machinery and equipment used within radar antenna production. Within property maintenance, there are introduced planned and unplanned processes of servicing activities and machine and equipment repair. In a part of proposal for solution, there are recommended processes for keeping up production capabilities based on extensive analysis of size property influence on production volume. The method for reliability estimation of production chain is described for the antenna production, related to limiting production capability and costs to maintain service availability of production facilities.

This thesis explores using multi-scale topology optimization (TO) by utilizing inverse homogenization to automate the adjustment of each unit-cell's geometry and placement in a lattice structure within a pressure vessel (the design domain) to achieve desired structural properties. The aim is to find the optimal material distribution within the design domain as well as desired material properties at each discretized element and use machine learning (ML) to map microstructures with corresponding prescribed effective properties. Effective properties are obtained through homogenization, where microscopic properties are upscaled to macroscopic ones. The symmetry group of a unit-cell's elasticity tensor can be utilized for stiffness directional tunability, i.e., to tune the cell's performance in different load directions.  A few geometrical variations of a chosen unit-cell were homogenized to build an effective anisotropic elastic material model by obtaining their effective elasticity. The symmetry group and the stiffness directionality of the cells’ effective elasticity tensors were identified. This was done using both the pattern of the matrix representation of the effective elasticity tensor and the roots of the monoclinic distance function. A cell library of symmetry-preserving variations with a corresponding material property space was created, displaying the achievable properties within the library. Two ML models were implemented to map material properties to appropriate cells. A TO algorithm was also implemented to produce an optimal material distribution within a design domain of a pressure vessel in 2D to maximize stiffness. However, the TO algorithm to obtain desired material properties for each element in the domain was not realized within the time frame of this thesis.  The cells were successfully homogenized. The effective elasticity tensor of the chosen cell was found to belong to the cubic symmetry group in its natural coordinate system. The results suggest that the symmetry group of an elasticity tensor retrieved through numerical experiments can be identified using the monoclinic distance function. If near-zero minima are present, they can be utilized to find the natural coordinate system. The cubic symmetry allowed the cell library's material property space to be spanned by only three elastic constants, derived from the elasticity matrix. The orthotropic symmetry group can enable a greater directional tunability and design flexibility than the cubic one. However, materials exhibiting cubic symmetry can be described by fewer material properties, limiting the property space, which could make the multi-scale TO less complex. The ML models successfully predicted the cell parameters for given elastic constants with satisfactory results. The TO algorithm was successfully implemented. Two different boundary condition cases were used – fixing the domain’s corner nodes and fixing the middle element’s nodes. The latter was found to produce more sensible results. The formation of a cylindrical outer shape could be distinguished in the produced material design, which was deemed reasonable since cylindrical pressure vessels are consistent with engineering practice due to their inherent ability to evenly distribute load. The TO algorithm must be extended to include the elastic constants as design variables to enable the multi-scale TO.

Calcific aortic valve disease (CAVD) is one of the most common causes of cardiovascular disease in North America. Mechanical factors have been closely linked to the pathogenesis of CAVD and may contribute to the disease by actively regulating the mechanobiology of valve interstitial cells (VICs). Mechanical forces affect VIC function through interactions between the VIC and the extracellular matrix (ECM). Studies have shown that the transfer of mechanical stimulus during cell-ECM interaction depends on the local material properties at hierarchical length scales encompassing tissue, cell and cytoskeleton. In this thesis, biomechanical tools were developed and applied to investigate hierarchical cell-ECM interactions, using VICs and valve tissue as a model system. Four topics of critical importance to understanding VIC-ECM interactions were studied: focal biomechanical material properties of aortic valve tissue; viscoelastic properties of VICs; transduction of mechanical deformation from the ECM to the cytoskeletal network; and the impact of altered cell-ECM interactions on VIC survival. To measure focal valve tissue properties, a micropipette aspiration (MA) method was implemented and validated. It was found that nonlinear elastic properties of the top layer of a multilayered biomaterial can be estimated by MA by using a pipette with a diameter smaller than the top layer thickness. Using this approach, it was shown that the effective stiffness of the fibrosa layer is greater than that of the ventricularis layer in intact aortic valve leaflets (p<0.01). To characterize the viscoelastic properties of VICs, an inverse FE method of single cell MA was developed and compared with the analytical half-space model. It was found that inherent differences in the half-space and FE models of single cell MA yield different cell viscoelastic material parameters. However, under particular experimental conditions, the parameters estimated by the half-space model are statistically indistinguishable from those predicted by the FE model. To study strain transduction from the ECM to cytoskeleton, an improved texture correlation algorithm and a uniaxial tension release device were developed. It was found that substrate strain fully transfers to the cytoskeletal network via focal adhesions in live VICs under large strain tension release. To study the effects of cell-ECM interactions on VIC survival, two mechanical stimulus systems that can simulate the separate effects of cell contraction and cell monolayer detachment were developed. It was found that cell sheet detachment and disrupted cell-ECM signaling is likely responsible for the apoptosis of VICs grown in culture on thin collagen matrices, leading to calcification. The studies presented in this thesis refine existing biomechanical tools and provide new experimental and analytical tools with which to study cell-ECM interactions. Their application resulted in an improved understanding of hierarchical valve biomechanics, mechanotransduction, and mechanobiology.

Calcific aortic valve disease (CAVD) is one of the most common causes of cardiovascular disease in North America. Mechanical factors have been closely linked to the pathogenesis of CAVD and may contribute to the disease by actively regulating the mechanobiology of valve interstitial cells (VICs). Mechanical forces affect VIC function through interactions between the VIC and the extracellular matrix (ECM). Studies have shown that the transfer of mechanical stimulus during cell-ECM interaction depends on the local material properties at hierarchical length scales encompassing tissue, cell and cytoskeleton. In this thesis, biomechanical tools were developed and applied to investigate hierarchical cell-ECM interactions, using VICs and valve tissue as a model system. Four topics of critical importance to understanding VIC-ECM interactions were studied: focal biomechanical material properties of aortic valve tissue; viscoelastic properties of VICs; transduction of mechanical deformation from the ECM to the cytoskeletal network; and the impact of altered cell-ECM interactions on VIC survival. To measure focal valve tissue properties, a micropipette aspiration (MA) method was implemented and validated. It was found that nonlinear elastic properties of the top layer of a multilayered biomaterial can be estimated by MA by using a pipette with a diameter smaller than the top layer thickness. Using this approach, it was shown that the effective stiffness of the fibrosa layer is greater than that of the ventricularis layer in intact aortic valve leaflets (p<0.01). To characterize the viscoelastic properties of VICs, an inverse FE method of single cell MA was developed and compared with the analytical half-space model. It was found that inherent differences in the half-space and FE models of single cell MA yield different cell viscoelastic material parameters. However, under particular experimental conditions, the parameters estimated by the half-space model are statistically indistinguishable from those predicted by the FE model. To study strain transduction from the ECM to cytoskeleton, an improved texture correlation algorithm and a uniaxial tension release device were developed. It was found that substrate strain fully transfers to the cytoskeletal network via focal adhesions in live VICs under large strain tension release. To study the effects of cell-ECM interactions on VIC survival, two mechanical stimulus systems that can simulate the separate effects of cell contraction and cell monolayer detachment were developed. It was found that cell sheet detachment and disrupted cell-ECM signaling is likely responsible for the apoptosis of VICs grown in culture on thin collagen matrices, leading to calcification. The studies presented in this thesis refine existing biomechanical tools and provide new experimental and analytical tools with which to study cell-ECM interactions. Their application resulted in an improved understanding of hierarchical valve biomechanics, mechanotransduction, and mechanobiology.