Evaluation of Exhaust Gas Condensing Economizer Installation at Riga CHP Plants

In this study, passive exhaust gas condensing economizer installation is evaluated at Riga CHP plants No. 1 and No. 2 to increase efficiency of heat only boilers (HOBs). Five options are investigated: two options for Riga CHP plant No. 1 and three options for Riga CHP plant No. 2. The study provides the analysis of HOBs operation statistics, determination of HOBs operation trends, development of production programmes, as well as economic and sensitivity analysis of the considered options. Based on economic analysis, the best option for installation of passive exhaust gas condensing economizer for Riga CHP-1 and Riga CHP-2 was chosen

Mitral paravalvular abscess with left ventriculo-atrial fistula in a patient on dialysis

Background: Infective endocarditis in hemodialysis patients is challenging but is becoming more common recently. Case report: A 64-year-old man with end-stage renal disease on hemodialysis presented with infective endocarditis of mitral valve and coronary artery disease after commencing training for home hemodialysis. During a course of antibiotic treatment the patient developed left ventriculo-atrial fistula due to mitral paravalvular abscess. Abscess debridement followed by reconstruction of the mitral annulus with fresh autologous pericardial patch and mitral valve replacement using a mechanical prosthesis with concomitant coronary artery bypass grafting was performed successfully. Conclusion: Timely diagnosis, proper antibiotic treatment and early surgical intervention including aggressive debridement should improve the outcome of this high-risk disease. © 2009 Kitamura et al; licensee BioMed Central Ltd.Tadashi Kitamura, James Edwards, Suchi Khurana and Robert G Stukli

Endothelial denudation of isolated human internal mammary artery segments

Background: Endothelial denudation is an important approach to evaluate the role of the endothelium in vascular reactivity studies. Although approaches to remove the endothelium are well established in animal models, these methods have proved difficult to effectively translate to remnants of human Internal Mammary Artery (IMA) obtained during coronary bypass. This study sought to identify the optimal technique for endothelial denudation of IMA while preserving vascular contractile responses. Methods: IMA segments were subject to endothelial denudation using one of the following techniques: (1) surface abrasion, rubbing with a stainless steel wire, (2) vasoconstriction abrasion or (3) shear abrasion via infusion of an effervescent solution. Following intervention, IMA segments were evaluated by: (1) histochemistry to quantify structural damage and endothelial cell abundance and (2) functional endothelium-dependent vasodilator response using vascular myography in an organ bath preparation. Results: Vasoconstriction abrasion removed endothelial cells and caused disruption of the internal elastic lamina, these vessels failed to respond to the vasoconstrictor Phenylephrine (PE) or the endothelium-dependent vasodilator A23187. Surface abrasion alone was incomplete in removing endothelial cells, vessel vasodilated partially when challenged with A23187 in the presence of PE. Shear abrasion removed endothelial cells most effectively, as these pre-constricted vessels did not relax to A23187 but demonstrated increased sensitivity to PE. Conclusions: In this controlled comparative study assessing both structural and functional endpoints of endothelial denudation techniques, we have demonstrated that shear abrasion by infusion of an effervescent solution is the optimal technique to remove the endothelium and preserve vascular function in human IMA.Victor Lamin, Michael Worthington, James Edwards, Fabiano Viana, Robert Stuklis, David Wilson and John Beltram

Europe but not quite Europe? : a poststructuralist perspective of Latvia’s liminal Europeanness through the annual foreign policy debate over 2011 to 2021

Historically, Latvia has held a marginal position within the political geography of Europe. Yet, with the restoration of the state and in moving away from the Soviet Union, Latvia reorientated its national identity towards Europe and the West. In doing so, the European Union (EU) was one of the main foreign policy objectives. In the accession process to the EU, Latvia underwent a process of Europeanization, with changes at the domestic level and was placed in an inferior position to the EU. Since 2004, Latvia has further integrated into the EU, yet different geopolitical events have also created tensions between Latvia and the EU. Considering these developments, this thesis explores how Latvia has discursively constructed its national identity in relation to the EU over the last ten years. The theoretical framework of poststructuralism assumes that national identity is discursively and relationally constructed in a complex relationship to the Other. Adding to this, the concept of liminality which refers to the in-between space between the Self/Other is utilised. Through poststructuralism, foreign policy draws on national identity constructions and national identity is constructed through foreign policy. Therefore, in order to analyse Latvia’s national identity in relation to the EU, the thesis will examine the discussions on EU related topics within the annual foreign policy debate held in the Latvian parliament of the Saeima from 2011 to 2021. In examining the empirical material, the thesis utilizes Lene Hansen’s methodology of poststructuralist discourse analysis and approach of deconstructing articulations of differentiation within relational identity. In conducting the poststructuralist discourse analysis, three main findings of Latvia’s national identity construction in relation to the EU are identified. Firstly, Latvia’s national identity is on an equal level with the EU, but as shaped through its national context. Secondly, the Latvian Self is placed in an inferior position to the EU, as Latvia remains within the liminal space and becoming fully European is unreachable. Thirdly, the Latvian Self is superior to the EU, as Latvia goes beyond and against the positionings of the EU. These results indicate the historical continuity of Latvia’s liminality and how marginal actors contribute to their own ambiguous position. Latvia’s contemporary national identity is articulated as being ‘Europe but not quite Europe’, as the Self is constructed to the Other through shades of differentiation. Latvia reinforces its own liminal identity as the EU continues to define what it means to be ‘European’

Materials Consumption Decrease for Long-Span Prestressed Cable Roof

Limited raw materials and energy resources are actual national economy problems which can be solved by the decrease of weight, increase of span and durability of load bearing structures. The largest structural spans were achieved by application of cable structures. The roofs are one of the most widely used in practice type of cable structures.  However, increased deformability and necessity of the special methods of stabilizing are significant cable roofs disadvantages. The prestressing of one or several groups of cables is one of the probable methods for stabilizing of cable roofs. According to the recommendations available in the literature, all cables of the roof must be prestressed by the equal forces. But after applying of design vertical load, values of the forces, acting in the cables of the roof, changes within the wide limits. So, using of structural materials will not be rational in this case, taking into account, that the cables cross-sections are constant because the cables cross-sections were determined basing on the maximum axial force, acting in the all cables.Possibility to decrease materials consumption by the changing of prestressing forces for cables of the roof was checked on the example of saddle-shaped cable roof with the rigid support contour and dimensions 60x60 m in the plan. Initial deflections of main suspension and stressing cables of the roof were equal to 7m.  Suspension and stressing cables of the net were placed with the step equal to 2.828 m. Steel ropes with modulus of elasticity in 1.5∙105 MPa  were considered as a material of suspension and stressing cables of the roof. Suspension and stressing cables were divided into the groups, which are differed by the prestressing forces. Amount of cables groups changes within the limits from 1 to 27. Values of prestressing forces for cables groups change within the limits from 20 to 80% from the cables breaking force.  The dependences of material consumption and maximum vertical displacements of cable roof on the amount of cables groups and prestressing forces were determined as second power polynomial equations. It was stated, that division of suspension and stressing cables on the 18 groups enables to decrease cables material consumption by 19.2%. Values of prestressing forces for suspension and stressing cables of the roof were equal to 57 and 80 %, from it load-carrying capacity, correspondingly.

Revisionist national narratives in the memoirs of Estonian and Latvian Waffen-SS Legionnaires

No abstract available