Supplementary Cementitious Materials and Additives – Effective Measures to Hinder Radon in Concrete

The second largest cause of lung cancer is related to radon (222Rn) and its progenies in our environment. Building materials, such as concrete, contribute to the production of radon gas through the natural decay of 238U from its constituents. The Swedish Cement and Concrete Research Institute (CBI) has examined ten different concrete recipes containing an additive or Supplementary Cementious Material (SCM), such as fly ash, slag or silica and combinations thereof. The SCM´s were added in small to moderate portions and substituted the reference Portland cement (OPC). The inputs of an additive as well as a supplementary cementitious material were made as a mean to investigate their potential influence on the radon exhalation rates of the concrete as well as the radon gas diffusion length (L) that could be expected from the different recipes. Measurements were performed with an ATMOS 33 ionizing pulsation chamber. The results indicate a reduction of the exhalation rate by approximately 10-55 % depending on recipe at an RH of 75 %. The diffusion coefficients, corrected for background subtraction vary in the interval 1.1 x 10-10 – 7.6 x 10-12 m/s2. The diffusion lengths vary between 2 and 9 mm. In the case where the largest reduction of the exhalation rate is achieved, this roughly correspond to >2 mSv per year decrease in effective dose to a human. Consequently, using an additive or a SCM, as part of the mix, would be an option to effectively lower the radon gas exhalation in their initial stage of production. Secondly, the use of additives and SCM´s will contribute to a lower environmental impact (CO2).

Mathematical Modelling of Photocatalytic Hydrogen Production from Glucose on Ru-Doped LaFeO3

In the present work the authors proposed a simplified mathematical model for the renewable hydrogen production by the photocatalytic degradation of glucose over an optimized Ru-doped LaFeO3 photocatalyst under UV irradiation emitted by light-emitting diodes (LEDs). To define the reaction system the analysis of liquid phase was coupled with the detection of reaction products in gaseous phase. The mathematical modeling of the system has been developed by using different kinetic approaches for glucose consumption. Model parameters estimation was realized by individuating the best agreement between the calculated values and experimental data as a function of irradiation time both for hydrogen production and glucose degradation degree evidencing that the best fitting has been obtained with zero order kinetic models. Finally, the accuracy of the model was tested in different experimental conditions, evidencing the ability of the mathematical model to be predictive.

Failure Analysis of Gas Turbine Rotary Blade

In the present work the first stage rotor blade of a two- stage gas turbine has been analyzed for structural, thermal using ANSYS 9.0, which is a powerful Finite Element Software. In the present work, the first stage rotor blade of the gas turbine has been analyzed for the mechanical and radial elongations resulting from the tangential, axial and centrifugal forces. The gas forces namely tangential, axial were determined by constructing velocity triangles at inlet and exist of rotor blades. The rotor blade was then analyzed using ANSYS 9.0 for the temperature distribution. The material of the blade was specified as N155 but its properties were not given. This material is an iron based super alloy and structural and thermal properties at gas room and room temperatures. The turbine blade along with the groove is considered for the static, thermal, modal analysis. The first stage rotor blade of a two-stage gas turbine has been analyzed for structural, thermal using ANSYS 9.0 Finite Element Analysis software.

Failure Analysis of Gas Turbine Rotary Blade

In the present work the first stage rotor blade of a two- stage gas turbine has been analyzed for structural, thermal using ANSYS 9.0, which is a powerful Finite Element Software. In the present work, the first stage rotor blade of the gas turbine has been analyzed for the mechanical and radial elongations resulting from the tangential, axial and centrifugal forces. The gas forces namely tangential, axial were determined by constructing velocity triangles at inlet and exist of rotor blades. The rotor blade was then analyzed using ANSYS 9.0 for the temperature distribution. The material of the blade was specified as N155 but its properties were not given. This material is an iron based super alloy and structural and thermal properties at gas room and room temperatures. The turbine blade along with the groove is considered for the static, thermal, modal analysis. The first stage rotor blade of a two-stage gas turbine has been analyzed for structural, thermal using ANSYS 9.0 Finite Element Analysis software.

Suburban Public Transport Network Optimization and Operation Strategy of the New Bus Station in Bratislava

This article presented is aimed at identifying opportunities to improve the attractiveness of public transport, particularly that of the suburban bus service, thus providing for its precedence over individual car traffic in the city of Bratislava and its agglomeration in the Bratislava region. The subject is oriented to the impact of proposed changes in the transport operation and organisation from regional public transport point of view to the area adjacent to the city centre, especially in terms of the significant position of Mlynské Nivy Bus Station (MN Bus Station) which is now under complete rebuilding. The solution is shown how id possible to be a part of the integrated public transport services and the mylne zmýšľajúca competition among the operators especially state against private ones. Using the suburb lines as an express bus service on the area of the city is one of the possibility to operate pravisdelne during the all days in the city and not only to cover the rush hours.

Flood Risk Management: Case Study on Institutional Models

This paper presents the findings of an interdisciplinary review of possible country level institutional model alternatives for adopting flood risk management in the Republic of Macedonia, by harmonizing the national water management, and other related systems with the requirements of the EU Floods Directive. Based on the application of Analytic Hierarchy Process (AHP) theory, a tailor-made institutional model for integrated risk-based flood management is proposed as a substitute of the current ineffective flood management approaches that are based on purely engineering/design-based standards and ad-hoc interventions to flood events. It discusses the benefits of introducing the model and outlines the key preconditions to its operationalization. Given the similarity of existing flood management systems in the countries of the wider region, these findings can be used for initiating similar improvements in line with the contemporary flood risk management principles.

Experimental and Theoretical Study of Dielectric Permeability of Nonpolar Gases

In the present paper we consider application of equation of state for model gases to the description of experimental dependencies of dielectric permeability on pressure and temperature for nonpolar gases. The case of argon is regarded as an example. It is demonstrated that the generalized Van-der-Waals-Berthelot equation describes the dependence of dielectric permeability on pressure and temperature with good accuracy. It is shown that the measurement of dielectric permeability using the isotherms with small temperature increments provides a means to obtain the exact tabulated equation of state. This result can be used in other areas of investigation.

Experimental and Theoretical Study of Dielectric Permeability of Nonpolar Gases

In the present paper we consider application of equation of state for model gases to the description of experimental dependencies of dielectric permeability on pressure and temperature for nonpolar gases. The case of argon is regarded as an example. It is demonstrated that the generalized Van-der-Waals-Berthelot equation describes the dependence of dielectric permeability on pressure and temperature with good accuracy. It is shown that the measurement of dielectric permeability using the isotherms with small temperature increments provides a means to obtain the exact tabulated equation of state. This result can be used in other areas of investigation.