Browse

You are looking at 1 - 10 of 680 items for :

  • Environmental Management x
Clear All
Open access

Denisa Valachova, Nada Zdrazilova, Vladan Panovec and Iveta Skotnicova

Abstract

For the best possible thermal-technical properties of building structures it is necessary to use materials with very low thermal conductivity. Due to the increasing thermal-technical requirements for building structures, the insulating materials are developed. One of the modern thermal insulating materials is so-called aerogel. Unfortunately, this material is not used in the field of external thermal insulation composite systems because of its price and its properties. The aim of this paper is to present possibilities of using this insulating material in the civil engineering - specifically a usage of aerogel in the production of windows.

Open access

Jana Vlčková, Nikola Kaspříková and Markéta Vlčková

Abstract

The level of technological specialisation in the regions of Germany is assessed in this paper, as well as how such specialisation has evolved over time. Further, in three selected regions (Munich, Düsseldorf and Oberes Elbtal/Osterzgebirge), the knowledge space is explored in detail and compared to existing smart specialisation strategies. Average relatedness and knowledge space based upon EPO patent applications are used to measure the specialisation and technology trajectories of the German regions. Between three periods 1988–1992, 1998–2002 and 2008–2012, the specialisation of Germany based on EPO patent applications increased by 10%, despite a decline in many regions. Machinery and transportation industries have increased their significance. The assessment of regional smart specialisation strategies in the three German states shows that the methodology in terms of the identification of prospective industries is largely variegated and insufficiently developed. More attention should also be given to the choice of an appropriate geographical level of aggregation for analysis. Knowledge relatedness and knowledge complexity could be used as methodological tools for selecting prospective industries in smart specialisation strategies.

Open access

Lekë Pula and Alban Elshani

Abstract

The aim of the study is to examine the impact of public expenditure on economic growth of Kosovo. Time series data span for the period of time 2002-2015. The structure of the econometric model is built on Keynesian theories and endogenous growth model. The model estimation is performed only after implementing the Augmented Dickey-Fuller (ADF) Unit Root test to estimate if time series are stationary. Several tests have been implemented to determine model validity. The model has met all the assumptions of statistical tests: error term residuals have a normal distribution (Jarque-Bera test), there is no auto-correlation between variables (Breusch-Godfrey Serial test), and error variances are constant, known as the principle of homoscedasticity (Breusch-Pagan-Godfrey test). Gross domestic product is used as a dependent variable in the model, while public expenditure (G), foreign direct investment (FDI), export (EXP) and total budget revenue (TrTax) are used as the endogenous variables. The study results have revealed that there is a positive and statistically significant effect of public expenditures and exports on economic growth. Total budget revenue has a positive impact on economic growth but this has not been proved to be statistically significant. The authors of the research have also found out that FDI is negative and statistically insignificant.

Open access

Maciej Major, Izabela Major, Daniela Kuchárová and Krzysztof Kuliński

Abstract

The paper presents numerical analysis of block made of three layers: concrete with I-shape rubber pads, space filled with air and concrete with embedded cross rubber pads, respectively. The block is subjected to the dynamic load. To the analysis as rubber the hyperelastic incompressible Zahorski material model was assumed. This material well describes the real material properties in the range of large elastic deformations. Embedded rubber pads provide an additional protection against the transversal dynamic load. ADINA software was utilized to perform numerical analysis of determining the percentage damping factor of rubber-concrete composite in comparison with block made of concrete.

Open access

Leonid Diachenko, Andrey Benin, Vladimir Smirnov and Anastasia Diachenko

Abstract

The aim of the work is to improve the methodology for the dynamic computation of simple beam spans during the impact of high-speed trains.

Mathematical simulation utilizing numerical and analytical methods of structural mechanics is used in the research.

The article analyses parameters of the effect of high-speed trains on simple beam spanning bridge structures and suggests a technique of determining of the dynamic index to the live load. Reliability of the proposed methodology is confirmed by results of numerical simulation of high-speed train passage over spans with different speeds. The proposed algorithm of dynamic computation is based on a connection between maximum acceleration of the span in the resonance mode of vibrations and the main factors of stress-strain state. The methodology allows determining maximum and also minimum values of the main efforts in the construction that makes possible to perform endurance tests. It is noted that dynamic additions for the components of the stress-strain state (bending moments, transverse force and vertical deflections) are different. This condition determines the necessity for differentiated approach to evaluation of dynamic coefficients performing design verification of I and II groups of limiting state. The practical importance: the methodology of determining the dynamic coefficients allows making dynamic calculation and determining the main efforts in split beam spans without numerical simulation and direct dynamic analysis that significantly reduces the labour costs for design.

Open access

Jozef Prokop and Josef Vičan

Abstract

Verification of beam-column resistance can be accomplished according to design approaches given in EN 1993-1-1 [1]. These approaches are derived from verification of single span beam with pinned end conditions subjected to compression and bending moments. In the case of different end conditions, the application of those approaches is not so accurate and more difficult. Therefore, the comparison of verification according to above standard EN 1993-1-1 [1] as well as EN 1999-1-1 [2] to results of experimental analyses of beam-columns having pinned-fixed end conditions subjected to an eccentric compressive force simulating the behaviour of columns integrated into frames is presented in this paper.

Open access

Martin Decký, Matúš Kováč, Juraj Mužík, Lenka Mičechová and Lukáš Ďuriš

Abstract

The article deals with the road pavement surface morphology objectification in term of the surface unevenness degradation during the life cycle of bus stop pavements. The article presents the results of long-term rut depth measurements performed during 25 years on selected bus stops which were intended to determine correlation dependences of pavement rut depth on a number of design axles. The article also presents different methods for rut depth measurements including the straightedge test, Profilograph GE, TRIMBLE CX, and dynamic Road Scanner.

Open access

Martina Margorínová, Mária Trojanová, Martin Decký and Eva Remišová

Abstract

Building and improving road infrastructure in Slovakia is currently influenced by the amount of state funding. Therefore, it is necessary to determine the effectiveness of each proposed solution of road project, which is based on life-cycle costs. Besides capital costs, social costs are also important, which valued the negative impacts due to road construction and operation on road users, the environment, and the population living in the affected area. Some components of social costs have shortcomings in quantifying and valuating, which need to be resolved. The one of important components which affects human health and the value of an area, and have some shortcomings are noise costs. Improvement of this component will lead to more accurate valuation of economic efficiency of roads.

Open access

Ali Vatanshenas, Mohammad Sadegh Rohanimanesh and Ehsan Mohammadiha

Abstract

One of the most important factors that make structures vulnerable to earthquakes is the short distance between structures and epicenter. Near-field earthquakes have special properties, such as increasing acceleration applied to the structure, which distinguishes them from far-field earthquakes. Therefore, the absorption of input energy for structures located near the faults is very important. Hence, by rotating the earthquake acceleration time history and comparing the resulting spectral acceleration response, the angle which applies the greatest force to the structure on the earthquake directivity side is obtained, and then the performance of a steel structure with viscoelastic dampers (VED) under near-field earthquakes with directivity feature is investigated. After analyzing the structure using nonlinear time history analysis, it was observed that the directivity phenomenon leads to significant increase in the force applied to the structure, but the viscoelastic dampers showed an acceptable performance in both states of with and without directivity.

Open access

Leszek Butowski

Abstract

As a subject of scientific investigation, evaluations of the attractiveness of tourist destinations have had a relatively long history, particularly among geographers and regional economists. Based on mathematical and psychological principles and using methods that combine the Analytical Hierarchy Process (AHP) and the Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE) approach, this research project constructs an evaluation structure used for the assessment of European coastal and offshore areas for sailing tourism. A case study with a three-level evaluation structure has been defined and tested. It contains: at the top of the hierarchy an overall objective defined as the attractiveness of the European coastal and offshore areas for sailing tourism; six criteria of evaluation (on the second level); and ten coastal areas (at the bottom level). This structure covers almost all the coasts around Europe, as they were the subjects of evaluation and comparison. The evaluation was carried out by a group of experts who made the assessment taking into account previously determined criteria with weights. The findings indicate that the AHP-PROMETHEE method may be a useful tool to evaluate the attractiveness of different destinations. It can be also used for practical purposes, particularly to determine strengths and weaknesses, as well as the competitive position, of given coastal areas in relation to others.