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Barium cerate exhibits high protonic conductivity, especially when doped by suitable trivalent ions. A possible approach to get the protonic conductor stable in the presence of CO 2 with relatively high protonic conductivity is the preparation of solid solutions of BaCe 1− x Me x O 3− δ (Me = Zr, Ti) doped simultaneously with acceptor ion. In this work selected properties of series of Ba(Ce 0.95 Ti 0.05 ) 1− y Y y O 3− δ (0 ≤ y ≤ 0.2) materials prepared by solid-state reaction method were investigated. X-ray diffraction (XRD), scanning electron microscopy (SEM) and direct current (DC) electrical measurements, including open cell voltage (OCV) measurements of electrochemical cells were used as experimental techniques. Structural studies have shown materials crystallized in orthorhombic Pmcn phase with the solubility limit of Y in Ba(Ce 0.95 Ti 0.05 ) 1− y Y y O 3− δ higher than 20 at.%. The DC conductivity measurements accompanied by the potentiometric OCV measurements of solid state electrochemical cells in controlled gas atmospheres (containing H 2 , O 2 and H 2 O) and temperatures (500–800 °C) allowed determination of total electrical conductivity and transference numbers of oxygen, protonic and electronic defects in prepared materials. The introduction of Y increases total electrical conductivity and transference numbers for protonic defects, which was correlated with structural changes.

Silver and yttrium dopants influence some physico-chemical properties of BaCeO 3 protonic conduction. Ag -acceptor dopant substituting Ba atom in BaCeO 3 compounds was studied for the first time. Ba 1-x Ag x Ce 1-y Y y O 3-δ (0 ≤ x ≤ 0.1, 0 ≤ y ≤ 0.1) materials were synthesized by solid state reaction and by modified Pechini citric acid method. X-ray diffraction (XRD) and electrical properties measurements including open cell voltage (OCV) of electrochemical cells were used as experimental techniques. Basing on XRD results it was found that all synthesized materials crystallized in orthorhombic Pnma phase with some admixtures of other phases. Metallic Ag , CeO 2 or Y 2 O 3 with different concentrations were detected, depending on the composition, synthesis method and preparation details. DC electrical measurements showed that doping by Ag and Y decreased the total and ionic conductivities of the materials. The modification of charge transport properties was also observed, namely introduction of Ag led to the increase of electronic component of total electrical conductivity, especially at higher temperatures.

Eastern Poland as the Borderland of the European Union The purpose of the present paper is to characterise the socio-economic potentials of the regions situated on both sides of the Polish-Russian, Polish-Belarusian and Polish-Ukrainian boundaries (against the background of historical conditions), as well as the economic interactions taking place within these regions. The analysis, carried out in a dynamic setting, sought to identify changes that have occurred owing to the enlargement of the European Union (including those associated with the absorption of the means from the pre-accession funds and from the structural funds). The territorial reach of the analysis encompasses four Polish units of the NUTS 2 level (voivodeships, or "voivodeships"), situated directly at the present outer boundary of the European Union: Warmia-Mazuria, Podlasie, Lublin and Subcarpathia. Besides, the analysis extends to the units located just outside of the eastern border of Poland: the District of Kaliningrad of the Russian Federation, the Belarusian districts of Hrodna and Brest, as well as the Ukrainian districts of Volyn, Lviv and Zakarpattya.

Barium cerate exhibits high protonic conductivity, especially when modified by trivalent dopant such as Y, Yb, Nd, Sm or Dy. Unfortunately, the poor chemical stability in the presence of CO 2 is the main disadvantage of this material. One of the possible approach to get the stable protonic conductor is the preparation of solid solutions. For example, doping of BaCeO 3 with Zr leads to the improvement of the chemical stability, but the electrical properties are simultaneously corrupted. In the present work the influence of Ti, per analogy to Zr, and Y dopants on electrical properties of BaCeO 3 was investigated using the electrochemical impedance spectroscopy (EIS) technique. BaCe 1− x Ti x O 3− δ (0 ≤ x ≤ 0.3) and Ba(Ce 0.95 Ti 0.05 ) 0.95 Y 0.05 O 3− δ solid electrolytes were prepared by solid-state reaction method. It was found that the changes of electrical properties due to the introduction of Ti into the BaCeO 3 lattice is caused predominantly by the modification of the grain boundary properties. The Ti doping leads to the substantial decrease of grain boundary electrical conductivity, comparing to undoped material. The introduction of yttrium dopant to the BaCe 0.95 Ti 0.05 O 3 lattice has the opposite effect. The total electrical conductivity increases, due to significant modification of grain boundary electrical properties.

Fe-substituted NASICON was prepared by co-precipitation method and the content of iron at different oxidation states was estimated by Mossbauer spectroscopy (MS). Compounds with different phase composition were obtained depending on the preparation procedure. In the case of samples sintered in reducing atmosphere, NASICON containing di- and trivalent iron was detected. The lattice constants were calculated by Rietveld method. Higher values of the unit cell parameters for Na3Zr1−yFe1−y2+Fe2y3+P3O12 compared to the structural analogue γ-Na3Fe2P3O12 indicated the partial replacement of smaller Fe3+ ions by bigger Fe2+ and Zr4+ in the NASICON lattice. The validation of Mossbauer spectroscopy as the useful tool in the calculation of iron content was also performed. The sintering in air led to the multiphase product, which was identified by XRD and MS.

The purpose of this work was to investigate the influence of titanium and yttrium dopants on chemical stability of selected Ba(Ce1−xTix)1−yYyO3 compounds. The presented results are the part of wider research concerning the crystallographic structure, microstructure, electrical and transport properties of these groups of materials. Samples of Ba(Ce1−xTix)1−yYyO3 with x=0.05, 0.07, 0.10, 0.15, 0.20, 0.30 and y=0.05, 0.10, 0.20 (for x=0.05) were prepared by solid-state reaction method. Initially, differential thermal analysis (DTA) and thermogravimetry (TG) were used for optimization of preparation conditions. Subsequently, DTA-TG-MS (mass spectrometry) techniques were applied for evaluation of the stability of prepared materials in the presence of CO2. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) results were used to determine the phase composition, structure and microstructure of materials and to assist the interpretation of DTA-TG-MS results. The strong influence of Ti and Y dopants contents (x and y) on the properties was found. The introduction of Ti dopant led to the improvement of chemical stability against CO2. The lower Ti concentration the better resistance against CO2 corrosion was observed. Doping by Y had the opposite effect; the decrease of chemical stability was determined. In this case the higher Y dopant concentration the better resistance was observed. The attempt to correlate the influence of dopant on structure and chemical stability was also presented.

Spatial accessibility is an increasingly popular indicator of assessing the level of development of transport infrastructure, and its impact on the development of particular territorial units. Among the most often used indexes of accessibility that can be applied to analyses prepared for the purposes of sea ports and coastal areas, are the following: ♦ time accessibility (presenting in a cartographic review how much time it takes to get to particular points), and accumulated accessibility; ♦ potential accessibility (presenting units positions on the background of general transportation network of a given mode). The aim of this study was to assess the potential road accessibility in the years 2015 and 2030, as well as the changes resulting from the investments planned for this period of time. In the study of accessibility to the network of the existing sea ports, there were taken into account: Elbląg, Gdańsk, Gdynia, Ustka, Darłowo, Kołobrzeg, Świnoujście, Police and Szczecin. Analyses of these ports’ time accessibility have been also performed. It has been established that none of the Polish ports can boast of sufficient road connections with important national centres, which are their vital economic hinterland. The situation in Tricity (Gdansk, Sopot, Gdynia) is most favourable, and its further improvement depends on completion of the S5 and S7 express roads, and on the implementation of investments within the agglomeration. Extending the Szczecin Lagoon ports’ hinterland is going to be more problematic though it will also take place after the S3 road is completed. The small ports on the central coast are accessible by the system of roads only to a very limited degree and are not likely to improve their situation in the years to come. Implementation of the S6 express road will alter this state only partially (because of it running latitudinally). An integrated, spatially big market can be found only in the Tricity region. No integration of this kind can be found in the Szczecin-Świnouj- ście complex, not to mention the central part of the coast. The planned investments are to increase the range of the Tricity metropolis’s employment market (e.g. by Elbląg), and will allow an integration of the market within the area of the Szczecin Lagoon. Renata Kozak

The access to Services of General Interest (SGI) is a highly relevant factor for territorial cohesion and in creating economic opportunity. Although the topic of SGI was not on the top of the policy agenda during the last decade, it attracts far more interest since the start of the economic crisis. Moreover, it is likely to be high on the regional development policy agenda for the years to come. The timely and consistent delivery of SGI is critical to the functioning of the modern welfare state which provides implicit and explicit support for the innovative and economically productive parts of the economy. Empirical evidence demonstrates the emergence of such trends in some regions of Europe (ESPON 2013). Historically, rural areas have been disadvantaged when it comes to what is today named as SGI. This has changed during the last decades and three arguments are usually given for this: (1) One of the EU?s key political goals is territorial cohesion, which aims at improving the conditions for the least advantaged regions; (2) SGI forms a central element in the ?European Model of Society?, i.e. access to services is considered a central element of quality of life, and increasing service accessibility a mechanism for overcoming social exclusion and isolation; and (3) SGI addresses the crucial question of what role public authorities should play in societies that are committed to both free markets and social goals (Nugera-Tur et al. 2009). This conclusion can thus be criticised as it only cover the period up to the financial crisis and mainly focuses on infrastructure, i.e. Services of General Economic Interest. SGI is not a homogeneous concept, but contains Services of General Economic Interest and Social Services of General Interest (Foss et al. 2013), and there are significant differences in the provision of Social Services of General Interest (SSGI) at a regional level in the EU (Humer & Palma 2013, Humer 2014). The knowledge gap when it comes to SSGI in rural areas calls for investigation. This paper aims at discussing the provision of SSGI in rural areas and three questions will be addressed: (1) what determines the provision of SSGI in rural areas. (2) How is SSGI provided in rural areas? If we find a gap between how SSGI can be provided and how it is actually provided we face a challenge to overcome which raises the question (3) how can this challenge be addressed?

Various composition of Na1+xSixZr2P3−xO12 (x from 1.6 to 2.4), Y-doped Nasicon (Na1+x+yZr2−yYySixP3−xO12 ,N a 1+xZr2−yYy SixP3−xO12−y, where x =2 ,y = 0.12) and Fe-doped Nasicon (Na3Zr2/3Fe4/3P3O12) were prepared by coprecipitating. Differential thermal analysis (DTA), thermogravimetry (TG), differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and impedance spectroscopy (IS) were used as experimental techniques. In order to obtain Nasicon materials free from ZrO2 admixture, the calcination of coprecipitates must be carried out in proper thermal conditions. The results of DTA, TG and XRD measurements allowed us to propose the best calcination conditions (to obtain mainly Nasicon phases – monoclinic or rhombohedral, depending on composition). Nasicon-type materials exhibit monoclinic to rhombohedral reversible structural transition, at transition temperature depending on composition (x). The influence of dopants was also studied. The DSC measurements in the temperature range RT–300 ◦ C allowed us to determine the temperatures of this structural transition in the case of Na 1+xSixZr2P3−xO12, and Y-doped Nasicon. In the case of Fe-doped materials this transition was not detected. Additionally, the correlation between the composition, microstructure and electrical properties was studied.

Mixed oxides from the TiO{sub 2}-WO{sub 3} system were prepared as polycrystalline materials. Their phase composition and electrical conductivity were investigated using X-ray diffraction (XRD) and dc electrical measurements. The energy gap, evaluated on the basis of optical measurements, was presented as a function of W concentration. The influence of chemical composition on structural, semiconducting and optical properties of the TiO{sub 2}-WO{sub 3} polycrystalline ceramics was discussed.

TiO2–WO3 thin films were prepared by radio frequency (r.f.) reactive sputtering from metallic target. Structural and morphological properties of the thin films have been studied through X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The influence of the annealing on the phase composition TiO2–WO3 system was studied. The binding energies of titanium and tungsten are characteristic for Ti4+ and W6+. The influence of tungsten on anatase–rutile phase transition in TiO2 was observed. The structural modeling has been performed to account the preferred orientation in tungsten doped titanium oxide.

Five solid-state potentiometric CO 2 sensors of the type: CO 2 , O 2 , Ag, M 2 CO 3 –BaCO 3 |Nasicon| X, Pt, O 2 (where M=Li or Na, X—Na 2 O activity buffer) were investigated. The effects of electrode composition and operating temperature on long-term performance of sensors were determined. It was found that the sensors with Na 2 Ti 6 O 13 /Na 2 Ti 3 O 7 reference electrode show stable signal during 1000 h. No effect of the sensing electrode composition was observed. The optimal operating temperature of the studied sensors was 748 K. The formation of liquid phase at this temperature at the sensing electrode/solid electrolyte interface is suspected to be responsible for improvement of the sensors performance. The reactivity between sensing electrode and solid electrolyte materials at higher temperatures leads to sensors instability.

Both undoped and Cr-doped TiO2 thin films were investigated. The dependencies of the flat band potential on pH, Cr concentration as well as thermal reduction were determined. On the basis of the photocurrent experiments, the effect of Cr concentration and high-temperature reduction on solar energy conversion efficiency was discussed. It was found that addition of Cr leads to an increase of the recombination process of photoelectronic carriers and shifts the flat band potential towards negative values. Linear changes of the flat band potential with pH of the electrolyte has been observed for both undoped and Cr-doped films. The maximum energy conversion efficiency (above 2%) has been observed for a voltage bias of ca. 0.1– 0.4 V . The highest energy conversion efficiency has been observed for undoped-TiO2 thin films. It reaches values of 1.9% and 2.2% for as sputtered and reduced samples, respectively.

The mutual reactivity in mixtures containing Nasicon (Na3Zr2Si2PO12) or YSZ (ZrO2:Y2O3) solid electrolytes with Li2CO3 or Li2CO3:BaCO3 sensing electrode materials was investigated using simultaneous DTA and TG and ex situ XRD techniques. The uncontrolled chemical reaction is suspected to be responsible for the instability of electrochemical gas sensors constructed from these materials. DTA and TG results obtained for Nasicon-carbonate mixtures indicate the possibility of reaction in the temperature range from about 470 to 650°C, which overlaps the sensor operating temperature range (300–525°C). The results obtained for YSZ-carbonate mixtures indicate that reaction between carbonate and the ZrO2 takes place at higher temperatures and cannot explain the instability drift of investigated sensors. The mechanism of observed reactions in systems studied is also discussed.

Solid-state potentiometric CO2 sensors were fabricated using Na+ conductor (Na3Zr2Si2PO12) as a solid electrolyte, Li2CO3–BaCO3 fused carbonate with different compositions as a sensing electrode and the Na2Ti6O13–Na2Ti3O7 or TiO2–Na2Ti6O13 two phase systems as a reference electrode. The measured electromotive force of the investigated cells was found to be linear with the logarithm of CO2 partial pressure in the range 100–12 600 ppm of CO2 and in the temperature range 300–500 °C. The response time was ca. 40–120 s. The sensors exhibited reproducible signal during short-time experiments (

Titanium dioxide thin films doped with up to 16 at.% of chromium were prepared by rf reactive sputtering. The effect of doping concentration on the structural, optical and electrochemical properties was studied. Modification of the electronic structure of titanium dioxide by chromium doping was established. The allowed states due to Cr were found to be situated in the forbidden band gap at about 2.5 eV below the bottom of the conduction band. Electrochemical measurements were performed in a three-electrode cell with the TiO2–Cr acting as anode. The impedance spectra and capacitance of the electrode/electrolyte interface versus voltage (Mott–Schottky plots) were recorded over a wide frequency range of 1–106 Hz. The flat band potential, effective donor density and depletion layer thickness were obtained from capacitance data as a function of the applied potential at 10 kHz.

Impedance spectra of the solid electrolyte (Nasicon) were investigated by means of complex impedance in the frequency range 0.1 Hz–1 MHz at temperatures between 298 and 873 K. A plausible equivalent circuit consisting of resistor and constant phase element in series was proposed. Pronounced effect of electrode structure on impedance spectra has been observed. The equivalent circuit for the sample with Pt blocking electrodes in the temperature range 298 K–773 K is composed mostly of the CPE element, representing electrode-material interface (Warburg impedance). On the other hand, the Nasicon sample with porous Pt electrodes may be simulated by the circuit formed from the resistance R and the CPE element in series. At 573 K and above the CPE element is reduced to the simple Debye capacitor. The determined electrical conductivity and activation energy of conductivity are in general agreement with those for bulk of Nasicon reported in the literature.

The behavior of the reference electrode (Na2Ti6O13--TiO2) and the electrode/solid electrolyte (Nasicon) interface of the electrochemical sensor were investigated by means of complex impedance spectra in the frequency range 0.1 Hz–1 MHz and at the temperatures between 298 K and 873 K. A plausible equivalent circuit involving two R-CPE elements connected in series was proposed. The results were discussed in terms of the brick-layer model. The parameters characterizing Schottky barrier occurring at the grain boundary interface were determined.

In this work, we present the results of X-ray diffraction, IR and Raman spectroscopy measurements of Li2CO3–BaCO3 system in a whole range of composition. The investigated samples were prepared by melting and cooling down of the powder mixtures, and their properties were compared to the samples before melting (physical mixtures of powders). XRD results of fused carbonates showed that there are only two phases present: monoclinic Li2CO3 and orthorhombic BaCO3, and there is no shift in XRD reflex position. It indicates that barium and lithium carbonates do not form substitution solid solutions. However, the changes of some XRD reflex intensities were observed, suggesting the formation of diluted interstitial solid solutions or microstructure modification after melting. In order to determine the structure and microstructure modification after heat treatment the IR and Raman spectroscopic measurements were performed. The obtained results suggest the formation of additional amorphous phase in fused carbonates.

The a.c. impedance response of polycrystalline ceramics SnxTi-x1O2 was studied in the air in the temperature range 298–1073 K. The impedance spectra were analyzed in terms of two proposed equivalent circuits involving both resistor and non-Debye constant phase element (CPE). The presence of CPE elements may be interpreted by diffusion phenomena. The results indicate a negligible contribution of grain boundary resistance to the total resistivity of the studied materials. The determined activation energy of the bulk conductivity of TiO2 was compared with literature data. © 2001 Kluwer Academic Publishers

The binary system Li2CO3–BaCO3 was studied by means of differential thermal analysis (DTA), thermogravimetry (TG) and X-ray phase analysis. The composition of carbonate and CO2 partial pressure influence on the thermal behavior of carbonate were examined. It was shown that lithium carbonate does not form the substitutional solid solution with barium carbonate, however the possible formation of diluted interstitial solid solutions is discussed. Above the melting temperature the mass loss is observed on TG curves. This loss is the result of both decomposition of lithium carbonate and evaporation of lithium in Li2CO3–BaCO3 system. Increase of CO2 concentration in surrounding gas atmosphere leads to slower decomposition of lithium carbonate and to increase the melting point.