Leakage current, ferroelectric and structural properties in Pb(1-x)Ba(x)TiO(3) thin films prepared by chemical route

Single-phase perovskite structure Pb(1-x)Ba(x)TiO(3) thin films (x = 0.30, 0.50 and 0.70) were deposited on Pt/Ti/SiO(2)/Si substrates by the spin-coating technique. The dielectric study reveals that the thin films undergo a diffuse type ferroelectric phase transition, which shows a broad peak. An increase of the diffusivity degree with the increasing Barium contents was observed, and it was associated to a grain decrease in the studied composition range. The temperature dependence of the phonon frequencies was used to characterize the phase transition temperatures. Raman modes persist above tetragonal to cubic phase transition temperature, although all optical modes should be Raman inactive. The origin of these modes was interpreted in terms of breakdown of the local cubic symmetry by chemical disorder. The absence of a well-defined transition temperature and the presence of broad bands in some interval temperature above FE-PE phase transition temperature Suggested a diffuse type phase transition. This result corroborates the dielectric constant versus temperature data, which showed a broad ferroelectric phase transition in these thin films. The leakage Current density of the PBT thin films was studied at different temperatures and the data follow the Schottky emission model. Through this analysis the Schottky barrier height values 0.75, 0.53 and 0.34 eV were obtained to the PBT70, PBT50 and PBT30 thin films, respectively. (C) 2008 Elsevier Ltd. All rights reserved.

Current and future shopping conditions in Sälen

Going from having bought the most essential at the small shops close to home, better communications and an increasingly consumption oriented lifestyle has created a change in shopping behavior and has led to phenomenon such as shopping centres and more. These are constantly being built in Sweden: in the cities, outside the cities and more recently even in small cities -small cities as for one reason or another have access to a larger customer base which can have businesses to flourish economically. During the first decade of the 21st century, shopping centres have been established along the Swedish/Norwegian border. Since the Norwegian Krone is much stronger than the Swedish Krona Norwegians save a great deal of money on going to Sweden to shop. During the shopping trips to Sweden, it is mostly alcohol, meat, tobacco and candy that are being bought. However, other products such as clothing, technology, household appliances and more are also being purchased, all to save money on the trip. Together these cross border shoppers spent 11, 6 billion in Sweden during the year of 2010. This gives an average spending of approximately 10 900 SEK per cross border shopper on annual basis. Nordby, Töcksfors and Charlottenberg (small cities located in southwestern Sweden) are places characterized by Norwegian cross border shopping. Together, they generate billions every year and this only seems to increase. These places are relatively small in size but have prominent attributes such as proximity to the Norwegian border. Apart from these resorts and shopping centres, there are few or none similar places near the Norwegian border in the rest of Sweden. However, a place which is geographically well located and has a relatively large Norwegian and Swedish customer base is the ski resort of Sälen in west central of Sweden. Sälen is a village located near the Norwegian border, although fairly sparsely populated. The destination has annually about one million official guest nights, based on the 414 000 visitors who stay an average of about 4, 5 days.  Per visit, these tourists individually spend an average of 862 SEK on shopping at the destination. The expenditure of the mountain tourists together with the Norwegian border shoppers makes it very interesting to explore the opportunities for shopping development in terms of a shopping centre in the region of Sälen.

Dynamic whole system testing of combined renewable heating systems : the current state of the art

Objective: For the evaluation of the energetic performance of combined renewable heating systems that supply space heat and domestic hot water for single family houses, dynamic behaviour, component interactions, and control of the system play a crucial role and should be included in test methods. Methods: New dynamic whole system test methods were developed based on “hardware in the loop” concepts. Three similar approaches are described and their differences are discussed. The methods were applied for testing solar thermal systems in combination with fossil fuel boilers (heating oil and natural gas), biomass boilers, and/or heat pumps. Results: All three methods were able to show the performance of combined heating systems under transient operating conditions. The methods often detected unexpected behaviour of the tested system that cannot be detected based on steady state performance tests that are usually applied to single components. Conclusion: Further work will be needed to harmonize the different test methods in order to reach comparable results between the different laboratories. Practice implications: A harmonized approach for whole system tests may lead to new test standards and improve the accuracy of performance prediction as well as reduce the need for field tests.