Conditions and costs for renewables electricity grid connection: Examples in Europe

This paper compares conditions and costs for RES-E grid connection in selected European countries. These are Germany, the Netherlands, the United Kingdom, Sweden, Austria, Lithuania and Slovenia. Country specific case studies are presented for wind onshore and offshore, biomass and photovoltaic power systems, as based on literature reviews and stakeholder interviews. It is shown that, especially for wind offshore, the allocation of grid connection costs can form a significant barrier for the installation of new RES-E generation if the developer has to bear all such costs. If energy policy makers want to reduce the barriers for new large-scale RES-E deployment, then it is concluded that the grid connection costs should be covered by the respective grid operator. These costs may then be recouped by increasing consumer tariffs for the use of the grid.     

Removal of free and complexed heavy-metal ions by sorbents produced from fly (Musca domestica) larva shells

Fly larva shells (FLS) are formed as a side product in the biological treatment of organic wastes, and chitin and chitosan produced from the FLS have been used as sorbents for heavy-metal ions. Sorbents are characterised by FT-IR measurements and pH-potentiometric titration and by determination of their surface area, and the content of main elements (C, N, P, S) and ashes. Free metal ions are sorbed best (up to 0.5-0.8 mmol g(-1)) onto chitin and chitosan. The sorption ability for free metal ions of chitin decreases in the order Fe(III) > Cu(II) (Pb(II) > Zn(II). > Ni(II) > Mn(II) and that of chitosan decreases in the order Cu(II) > Mn(II) > Ni(II) > Zn(II) > Pb(II) > Fe(III). The complexed metal ions are sorbed by the FLS up to 0.2-0.4mmol g(-1). The sorption ability for metal ions and ligands depends on pH, concentration of complexed metal ions and the ligand species in the solution. Glycine has the retarding effect on the sorption of Ni(II) and Cu(II) ions, and EDTA enhances the Cu(II) ion sorption. Ni(II) and glycine sorption obeyed the Langmuir isotherm. The observed sorption data show the promising potentialities of the FLS for the heavy-metal removal from the solutions, containing strong complexing agents. Mechanisms for the removal of free and complexed metal ions by chitin, chitosan and the FLS have been discussed.     

Nanocomposite films and coatings produced by interaction between graphite oxide and Congo red

Nanocomposite films and coatings were produced from the aqueous solutions containing different proportions of graphite oxide (GO) and Congo red by filtering through a polycarbonate membrane filter into alkaline media. They were examined by electron microscopy, Raman and FTIR spectroscopy, XRD, contact angle, and electrical conductivity measurements. It was established that the Congo red is able to interact through its amino groups with different functional groups of GO to form larger moieties composed of the nanoplatelets of GO. Raman spectroscopy revealed quinoid-like ring structure for dye adhering to the GO. In the case when the interaction occurs with the terminal functional groups located on the edges of the nanoplateletes of GO, larger crystallites in the nanocomposite are formed. The interaction between the Congo red and functional groups of GO situated in a basal plane leads to more compact structure of the nanocomposite. Pulsed laser treatment was used to reduce GO to graphene. Raman spectra of laser treated areas show positive effect of addition of the Congo red on the graphene yield in nanocomposite coatings after the laser treatment.     

Hydrogen influence on mechanical and fracture mechanics characteristics of zirconium Zr–2.5Nb alloy at ambient and elevated temperatures

This article deals with the investigation of the hydrogen concentration and temperature influence onto mechanical and fracture mechanics characteristics of RBMK-1500 Ignalina NPP unit 2 reactor fuel channel material—Zr–2.5Nb zirconium alloy (TMT-2) at temperatures from ambient up to 300 °C. The investigation of mechanical characteristics was performed on tensile specimens, fracture mechanics characteristics K_Q, , J_IC—on compact specimens (B = 4 mm) of hydrogen-free and saturated by hydrogen (52, 100 and 140 ppm) at 20, 170, 200 and 300 °C. The investigation showed that temperature increasing calls mechanical strength decreasing, whereas the reductions of area increase. Stronger influence of hydrogen concentration onto mechanical characteristics is noticed only at 20–170 °C temperature, however this influence diminishes as the temperature increases and weakest hydrogen influence is given at 300 °C. Fracture toughness characteristics K_Q, more depends on temperature than on hydrogen concentration. Critical J_IC integral values for the specimens containing hydrogen were given lowest at 20 °C, increases when temperature were raised up to 140 °C and were given highest when it reaches 300 °C.The analysis of and J_IC dependence due to the mechanical characteristics of zirconium alloy has showed that the modified plasticity Z_mod = (R_p0.2/R_m)Z satisfactorily approximates the influence of temperature and hydrogen concentration on variation of these characteristics.     

Dependence of ceramics physical–mechanical properties on chemical and mineralogical composition

To determine the dependence of physical–mechanical properties of ceramics on chemical and mineralogical composition, the appropriate raw materials have been tested and five batches of ceramic specimens have been formed. The aforementioned specimens have been made of the following components: fusible clay, quartz sand, chamotte, sawdust and crushed window glass. The specimens differed by the amount of the components (differences in burning regime were insignificant). After having formed and burned the specimens, their X-ray phase analysis has been carried out, elemental chemical composition has been defined and the composition of chemical oxides has been calculated. Moreover, the following physical–mechanical properties have been determined: density, general contraction and compressive strength. The test results showed that the physical–mechanical properties of ceramics mostly depend on the amount carbon, silicon and aluminum. The mineralogical structure of specimens under testing was practically unchanged.     

Sustainability assessment for recreational buildings

A large amount of natural resources and energy is wasted during and after the building construction process which might cause environmental problems such as climate changes. In order to achieve higher standards of environmental protection a range of building assessment systems has been established. However, they are mostly connected with the efficiency of an environmental protection and consumption of resources. Only few of them have limited possibilities to assess social and economic sustainability. A sustainable building includes aspects of environment, economy and society and therefore requirements to its assessment systems should be complex. We suggest that sustainability principles, that is, environmental, social and economic sustainability, should be estimated in the same equal weightings. The authors of this article created a model for assessing the sustainability for recreational buildings. Our model was created, in collaboration with experts, using breakdown, compensation and the analytic hierarchy process methods. The sustainability of Druskininkai Snow Arena (Lithuania) was assessed using a sustainability assessment system based on the proposed model.     

Influence of the rheological properties on the steel fibre distribution and orientation in self-compacting concrete

The interest in potential applications produced with self-compacting fibre reinforced concrete continues to grow, but in practice, problems associated with an uneven distribution and orientation of fibres in the concrete structure occur. It is not clear what exactly influences uneven distribution of fibres in self-compacting concrete (SCC) mixtures, especially during the casting and how different factors influence fibre orientation. The objective of this work was to investigate how rheological properties influence the steel fibre distribution in self-compacting concrete. This work also focuses on the investigation of steel fibre spatial orientation dependence on rheological properties of SCC, while keeping other casting parameters and the proportions of mixture components constant. Mixtures with three different rheological properties were chosen based on slump flow, slump flow time t₅₀₀ and static segregation values. The steel fibre orientation, volumetric concentration and spatial distribution values were determined in separate beam sections using three different non-destructive testing methods: electromagnetic induction, image analysis and computed tomography (CT scan). The comparison of the results is presented. The results show how different rheological properties of SCC affect the steel fibre orientation and distribution for the case of beams produced with the flow-induced casting method.     

The Nobel prize in physics - regularities and tendencies

Various distributions of the Nobel laureates in physics in the 20th century and their discoveries are considered. It is shown that the time-interval between the discovery and its recognition can be approximately described by a lognormal distribution. The ratio of the numbers of laureates awarded for the experimental and the theoretical discoveries was rather different in various decades; this was determined by some “waves” of discoveries and in the initial period probably by some subjective factors. The probability to obtain this prize for the theorist is larger than for the experimenter. The main part of the awards was given to the scientists working in the main fields of modern physics: small distances and solid state physics. Some fields of physics such as mathematical physics, relativity, statistical physics were ignored completely. The worrying tendency of an increasing average age of laureates towards their retirement age is indicated. This revised version was published online in June 2006 with corrections to the Cover Date.     

Oxygen Ion Conduction in Bulk and Grain Boundaries of Nominally Donor‐Doped Lead Zirconate Titanate (PZT): A Combined Impedance and Tracer Diffusion Study

Oxygen ion conduction in Nd³⁺‐doped Pb(Zr_xTi_1?x)O₃ (PZT) was investigated by impedance spectroscopy and ¹⁸O‐tracer diffusion with subsequent secondary ion mass spectrometry (SIMS) analysis. Ion blocking electrodes lead to a second relaxation feature in impedance spectra at temperatures above 600°C. This allowed analysis of ionic and electronic partial conductivities. Between 600°C and 700°C those are in the same order of magnitude (10^?5–10^?4 S/cm) though very differently activated (2.4 eV vs. 1.2 eV for ions and electron holes, respectively). Oxygen tracer experiments showed that ion transport mainly takes place along grain boundaries with partly very high local ionic conductivities. Numerical analysis of the tracer profiles, including a near‐surface space charge zone, revealed bulk and grain‐boundary diffusion coefficients. Calculation of an effective ionic conductivity from these diffusion coefficients showed good agreement with conductivity values determined from impedance measurements. Based on these data oxygen vacancy concentrations in grain boundary and bulk could be estimated. Annealing at high temperatures caused a decrease in the grain‐boundary ionic conductivity and onset of additional defect chemical processes near the surface, most probably due to cation diffusion.