University of Architecture, Civil Engineering and Geodesy

uacg.bg
Sofia, Bulgaria

The University of Architecture, Civil Engineering and Geodesy is located in Sofia, Bulgaria.It was founded in 1942 as a Higher Technical School following a decree issued on June 6, 1941 by the Bulgarian Tsar Boris III. In 1945 it was transformed into a State Polytechnic. In 1953 the Polytechnic was divided into several institutes one of them being the Institute of Civil Engineering. Since 1977 the institute is renamed Higher Institute of Architecture and Civil Engineering . In 1990 by a decision of its General Assembly the Institute was renamed University of Architecture, Civil Engineering and Geodesy , the official accreditation being voted by the Parliament on 21 July 1995. On 15.11.2001 received institutional accreditation. Wikipedia.

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Rizov V.,University of Architecture, Civil Engineering and Geodesy
Archive of Applied Mechanics | Year: 2017

The present paper describes a theoretical study of delamination fracture in the functionally graded multilayered Crack Lap Shear (CLS) beam configuration with taking into account the nonlinear material behaviour. The fracture was analysed in terms of the strain energy release rate. The analytical solution derived is applicable for CLS with an arbitrary number of layers. Also, the delamination crack may be located arbitrary along the beam height. The mechanical behaviour of beam layers was modelled by a power-law stress–strain relation. It was assumed that the material in each layer is functionally graded along the thickness. Also, the material properties may be different in each layer. An analytical solution of the J-integral was derived in order to verify the nonlinear strain energy release rate analysis. The effects were evaluated of material gradient, crack location along the beam height and material nonlinearity on the strain energy release rate. It was shown that the analysis developed is a useful tool for the understanding of delamination fracture behaviour of functionally graded multilayered CLS beam configurations with material nonlinearity. © 2017 Springer-Verlag Berlin Heidelberg


Grant
Agency: European Commission | Branch: FP7 | Program: CP | Phase: ENV.2011.3.1.9-2 | Award Amount: 3.03M | Year: 2011

EcoWater will address the development of meso-level eco-efficiency indicators for technology assessment through a systems approach. The effort will focus on enhancing the understanding of the interrelations of innovative technology uptake in water use systems, and their economic and environmental impacts. Research will address the selection of indicators appropriate for assessing system-wide eco-efficiency improvements, the integration of existing tools and assessment methods in a coherent modelling environment, and the analysis and characterisation of existing structures and policies. The development of an analytical framework is foreseen, to support: (i) Systemic environmental impact assessments, (ii) Economic assessments, (iii) Analysis of value chains and actor interactions, and (iv) Technology implementation and uptake scenarios. Eight Case Studies will be developed, in different systems and sectors of high economic relevance and environmental impact, addressing water use in agricultural, urban and industrial sectors. Two Case Studies will focus on shifts from rainfed to irrigated agriculture and innovations that can reduce water and energy footprints and production inputs. Two Case Studies will address sustainable and economically efficient water supply and wastewater management in urban areas. Four Case Studies will concern meso-level eco-efficiency improvements from innovative technologies in water systems for the textile industry, for energy production, for dairy production and in the automotive industry. The main outputs include a validated and tested methodological framework, an integrated toolbox for systems eco-efficiency analysis, and policy recommendations for technology uptake and implementation. For ensuring wide dissemination and applicability, the project foresees activities to address different target audiences and to develop operational science-industry-policy links at the level of Case Studies and at wider EU and international scale.


Grant
Agency: European Commission | Branch: FP7 | Program: CSA-CA | Phase: ENV.2010.4.1.4-1 | Award Amount: 1.22M | Year: 2010

Balkan countries do not have a coherent and continuous approach towards the challenge of implementing integrated Earth Observation (EO) applications in environmental monitoring and management. It should be mentioned that the Balkan countries, except Greece, are not ESA members. Besides, Albania, Serbia, Bulgaria, FYROM, Montenegro and Bosnia Herzegovina are also not members of the GEO. The defect in the implementation of EO applications and their use in the environmental decision making are manifested through the limited synergies among national and regional institutions, ineffective technological means and discontinuous record of participation to international organizations and committees. On the other hand, the increasing importance of a common approach towards effective environmental monitoring practices, for the benefit of the societal web of the broader Balkan region, calls for immediate action, setting as a starting point the built up of regional institutional capacity and spillage of technology transfer. The aim of the OBSERVE project is to collect and compile all the necessary information for delivering an integrated analysis on the current status of EO activities and networks in the Balkans regarding environmental monitoring, the potential benefit from the full exploitation of an integrated capacity building strategy and the prospect of creating a relevant permanent EO Community in the broader region. OBSERVE project has the ultimate goal to raise awareness and establish firm links with the regional decision making bodies on the importance of a mutual and enhanced EO application network on environmental monitoring according to the principles of the GEO. The OBSERVE project consortium consists of 15 institutions from 13 different countries, 8 of which belong to the Balkan region. 10 of the partners are Universities/Research Organizations while the other 5 are from private sector.


Grant
Agency: European Commission | Branch: FP7 | Program: CP-FP | Phase: ENERGY-2007-2.7-01 | Award Amount: 4.76M | Year: 2008

Small hydropower with very low head or pressure differences below 2.5 m and hydraulic power ratings of 50 to 1000 kW is a significant renewable resource, with an estimated unused potential in rivers alone of e.g. 600 to 1000 MW in the UK and more than 500 MW in Germany. The economically and ecologically efficient utilisation of this hydropower bracket still constitutes an unsolved problem since conventional turbines (Kaplan or Cross flow) are not cost effective, and since they are considered to have a negative ecological impact. In order to open up this hydropower bracket for exploitation, an innovative solution - the hydrostatic pressure turbine - was developed. This novel hydraulic machine utilises differential hydrostatic pressures; with theory and initial model tests indicating high theoretical efficiencies for low head differences. It rotates at slow speeds and operates under atmospheric pressure with a continuous bed, thus minimising negative impact on fish and allowing for unhindered sediment and fish passage. Initial work indicated significant development potential, whilst the expected structural simplicity promises increased cost effectiveness. Three configurations will be investigated for different applications in rivers with a head difference, for free stream situations and for energy generation in water supply systems. The configurations will be optimised using a combination of small and large scale model tests, theoretical and numerical modelling. The ecological impact will be assessed at every step of development, and fed back into the R/D process to achieve an ecologically effective design. In the absence of appropriate testing facilities, large scale tests will be conducted in natural rivers scenarios, adding to the realism of environmental impact assessment. The project is expected to develop, and prove, novel economically and ecologically effective hydropower converters for applications with head differences below 2.5 m.


Rizov V.,University of Architecture, Civil Engineering and Geodesy
Computational Materials Science | Year: 2013

Fracture behavior of polymer composites was investigated using Single Edge Notched Bending (SENB) specimens. The basic idea of this research was to check the ability of the SENB test method for generating mixed-mode I/II loading conditions by introducing an inclined notch as initial crack. For this purpose, SENB specimens containing a notch inclined at different angles were tested under static loading at room temperature. Three-dimensional finite element models were developed for simulating the mechanical response of the SENB test specimens. The test data were analyzed using methods of linear-elastic fracture mechanics. In order to validate the models, the predicted load-displacement responses were compared to the measured ones at different inclinations of the notch. From the experimentally measured crack growth initiation loads critical strain energy release rates at various mixed-mode I/II loading conditions were computed using the virtual crack closure technique. Non-uniform distribution of the critical strain energy release rate mode components along the crack front was obtained. It was found that besides modes I and II, there was also insignificant mode III component of the critical strain energy release rate. The simulations revealed that the relative amount of mode II component of the critical strain energy release decreased with increasing the notch inclination. It was shown that SENB specimens with inclined notch can be used for investigating fracture behavior of fiber reinforced polymer composites under various mixed-mode I/II crack loading conditions. © 2013 Elsevier B.V. All rights reserved.


Dimitrova E.,University of Architecture, Civil Engineering and Geodesy
Journal of Cleaner Production | Year: 2014

Based on a 10-year experience of embedding the 'sustainable development' topic into a newly established programme in Urbanism in Sofia, the paper discusses the influence of context, both geopolitical - Central and Eastern Europe (CEE), and professional-urban and regional planning, on the educational concept and the choices made on the modules' structure, contents and result evaluation. The estimation of the context relevance of the educational process and results addresses three aspects - advanced European practice in higher education for sustainable development, educational needs in the spatial planning field, and CEE regional peculiarities. Through analysing identified contextually rooted challenges and success factors in the educational process, and relating them to the broader global and regional process, the author claims the need for a better focused and contextually sensitive support to the local efforts for integrating the SD topic into the restructuring higher education institutions in the CEE region. © 2013 Elsevier Ltd. All rights reserved.


Apostolov A.T.,University of Architecture, Civil Engineering and Geodesy
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2014

In order to study the multiferroic properties of LiCu2O 2 we propose a microscopic model taking into account intra- and inter-chain magnetic interactions, frustration and a linear magnetoelectric (ME) coupling. The real part of the dielectric constant in c direction, c has two kinks near the magnetic phase transition temperatures TN2=22 K and TN1=25 K which disappear with increasing of an external magnetic field Hc. This behavior is an evidence for a strong ME coupling in agreement with the experimental data. The polarization Pc(T,H) is also calculated. It is shown that the ferroelectric properties do not uniquely originate from spiral spin order, so the linear ME coupling plays an important role. © 2014 Elsevier B.V. © 2014 Elsevier B.V. All rights reserved.


Ivanova S.M.,University of Architecture, Civil Engineering and Geodesy
Solar Energy | Year: 2014

This article presents a novel analytical approach to estimate the background component of diffuse irradiance on horizontal surfaces under partially obstructed anisotropic sky, when neighbor orthogonal vertical and horizontal surfaces hide parts of the sky dome. This helps to calculate the incident diffuse radiation onto horizontal roofs of orthogonal buildings using the defined here horizontal anisotropic sky view factors. The case of infinitely long urban canyon also is studied. The resulting equations include an isotropic part and an anisotropic correction. At last the article describes diffuse energy balance principles as a part of the base of anisotropic factor algebra. The article includes examples that demonstrate how new anisotropic view factors can be computed from a set of known factors with the help of anisotropic factor algebra. © 2013 Elsevier Ltd.


Radeva S.,University of Architecture, Civil Engineering and Geodesy
Nuclear Engineering and Design | Year: 2010

An approach for multiple-model structural control is developed for seismic protection of nuclear power plant, based on active structural control systems. Structural control provides opportunity to realize measures for reduction of seismic vulnerability of high risk structures, like nuclear power plants. The reliability of devices and systems for seismic protection is proved after modelling and simulation of seismic structural control with strong motion real or synthetic seismic signals, maximal close to the realistic ones. In suggested multiple-model system each sub-system corresponds to different actuator or combination of actuators for structural control of different parts of reactor building. After determination of frequency, characteristics, resonances and anti-resonances, is taken decision about reconfiguration of the structural control system. Simulation results for multiple-model active structural control system are shown. © 2009 Elsevier B.V. All rights reserved.


Ivanova S.M.,University of Architecture, Civil Engineering and Geodesy
Solar Energy | Year: 2013

This article presents an analytical approach to estimate the background component of diffuse irradiance on vertical surfaces under partially obstructed anisotropic sky, when neighbor orthogonal vertical and horizontal surfaces hide parts of the sky dome. This helps to calculate the incident diffuse radiation onto the façades of orthogonal buildings using defined here vertical and horizontal anisotropic sky view factors. The cases of infinitely long urban canyons and infinitely high vertical walls also are studied. The resulting equations include an isotropic part and an anisotropic correction. At last the article describes the fundamental relations between anisotropic sky view factors, which form base of anisotropic factor algebra. © 2013 Elsevier Ltd.

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