Recognizing the orthography changes for identifying the temporal origin on the example of the Balkan historical documents

Neural Computing and Applications - This paper introduces a new approach for automatically identifying the temporal origin of the digitized historical documents stored as images on the example from...     

Exploring the usability of the text-based CAPTCHA on tablet computers

This paper analyses and discusses the usability aspect of the text-based CAPTCHA in terms of response time and success in solving the CAPTCHA on tablet computers. The response time is the time spent by the user to find a solution to the CAPTCHA. The analysis is separately conducted on text-based CAPTCHA with only text and numbers. Then, the results are compared and the differences in response time and success in solving the two types of CAPTCHA are underlined. This is accomplished by asking 125 Internet users to solve the text-based CAPTCHA on the tablet computer. Their gender, age, education level, Internet experience, response time and success in solving two types of text-based CAPTCHA are collected in a dataset. Then, advanced statistical analysis by association rule mining is performed. It shows the dependence of the response time and success in solving the CAPTCHA on co-occurrence of gender, age, education level and Internet experience and the strength of this dependence by support, confidence and lift measures. This study provides relevant information for designing new CAPTCHAs which may be more accustomed to specific types of Internet users.     

Biochar as a viable carbon sequestration option: Global and Canadian perspective

Biochar production and mixing in soil are seen as the best options for atmospheric carbon sequestration, providing simultaneous benefits to soil and opportunities for distributed energy generation. The proximity of biomass source and biochar dispersal greatly reduces the energy and emissions footprint of the whole process. The viability of the whole biochar process is examined from two boundary points: is there enough biomass around to have significant impact on the atmospheric CO₂ levels and is there enough soil area for biochar dispersal. The answers are soundly positive, both for the world as a whole and for Canada, for which a more detailed analysis was done. However, the massive adoption of biochar solution is critically dependent on proper recognition of its carbon sequestration impact its soil improvement potentials. To that extent the International Biochar Initiative, together with national chapters, including recently formed Canadian Biochar Initiative, are actively promoting biochar related research and policy framework. This paper addresses the questions of availability of sources and sites that would benefit from its dispersal.     

Anomalous Grain Growth in Donor-Doped Barium Titanate with Excess Barium Oxide

Grain growth and semiconductivity of donor-doped BaTiO₃ceramics with an excess of BaO and additions of SiO₂or B₂O₃were studied. The microstructures and electrical measurements on sintered samples revealed that their electrical properties are related to the microstructure development of the sintered samples. Samples heated with an excess of BaO developed a normal microstructure during sintering, as a consequence of normal grain growth (NGG), and were yellow and insulating. In contrast, samples with an excess of BaO and an addition of SiO₂or B₂O₃exhibited anomalous grain growth (AGG) and were dark blue and semiconducting after sintering. When some BaTiO₃seed grains were embedded in a sample of donor-doped BaTiO₃with an excess of BaO (without SiO₂or B₂O₃), AGG was observed, i.e., some seed grains grew into large grains and were blue and semiconducting. An explanation is given for why AGG is responsible for the oxygen release and the formation of semiconducting grains in donor-doped BaTiO₃and not NGG.     

The development of the microstructural and electrical characteristics of NTC thick-film thermistors during firing

One kohm/sq. thick-film NTC thermistors (4993, EMCA Remex) with high, non-linear and negative temperature coefficients of resistivity were fired at different temperatures. The development of the resistors’ conductive phase and microstructure was investigated by X-ray diffraction analysis and by scanning electron microscopy. Sheet resistivities, beta factors and noise indices were measured as a function of the firing temperature. In the fired layers of the thermistors the X-ray analyses showed mainly spinel phase and RuO₂, which is added to the thick-film NTC materials to decrease the specific resistance and to improve the stability and the current noise. Higher firing temperatures led to more densely sintered microstructures, to increased resistivities and to higher beta factors. The higher resistivities were attributed to the partial exchange of ions on the “B” sites of the spinel structure with aluminium ions.     

Interactive image completion with perspective correction

We present an interactive system for fragment-based image completion which exploits information about the approximate 3D structure in a scene in order to estimate and apply perspective corrections when copying a source fragment to a target position. Even though implicit 3D information is used, the interaction is strictly 2D, which makes the user interface very simple and intuitive. We propose different interaction metaphors in our system for providing 3D information interactively. Our search and matching procedure is done in the Fourier domain, and hence it is very fast and it allows us to use large fragments and multiple source images with high resolution while still obtaining interactive response times. Our image completion technique also takes user-specified structure information into account where we generalize the concept of feature curves to arbitrary sets of feature pixels. We demonstrate our technique on a number of difficult completion tasks.     

Microstructural Changes during the Reduction/Reoxidation Process in Donor-Doped BaTiO3 Ceramics

Microstructural changes occurring during oxidation of the reduced form of donor-doped BaTiO₃ (Ba_{1− X} D _X ^.Ti_{1− X} ⁴⁺Ti _X ³⁺O₃) and during reduction of the oxidized form of donor-doped BaTiO₃ (Ba_{1− X} D _X ^.Ti_{1− X /4}⁴⁺( V _Ti^) _{X /4}O₃) were studied using TEM. Samples of both types of solid solutions, containing different La concentrations (from 2 to 20 mol% La), were prepared by sintering under reducing conditions and in air, respectively. The reduced form of donor-doped BaTiO₃ was oxidized by annealing at high temperatures (1150° and 1350°C) in air, while the oxidized form was reduced by annealing under reducing conditions. Because of oxidation of the reduced phase of donor-doped BaTiO₃, the Ti-rich phases Ba₆Ti₁₇O₄₀ and BaLa₂Ti₄O₁₂ were precipitated. Reduction of the oxidized form caused precipitation of the Ba-rich phase Ba₂TiO₄ preferentially inside the matrix grains. All precipitates had well-defined orientational relationships with the perovskite matrix.     

Iron nucleation mechanisms on vitreous carbon during electrodeposition from sulfate and chloride solutions

Iron nucleation mechanisms from aqueous solutions onto vitreous carbon electrode were comparatively investigated in iron sulfate and iron chloride systems by utilizing the electrochemical techniques of cyclic voltammetry (cv) and chronoamperometry (ca), coupled with atomic force microscopy (AFM) studies. The investigated parameters were pH, scanning rate, iron concentration, deposition potential and temperature. It was found that iron nuclei population density decreased with increase of pH. On the other hand, the population density increased with increase of iron concentration and cathodic deposition potential. Increase of solution temperature resulted in the increase of nuclei population density in the sulfate system, while the dependence of nuclei population density on temperature in the chloride system was more complex. The experimental electrochemical data fitted the theoretical model describing progressive nucleation mechanisms, which was also confirmed by the AFM morphological studies. In addition, the atomic force microscopy was successful in determining the possible crystallographic orientations of electrodeposited iron nuclei.     

Electrochemical activity of Li2FeTiO4 and Li2MnTiO4 as potential active materials for Li ion batteries: A comparison with Li2NiTiO4

We demonstrate, for the first time, a considerable electrochemical activity of two members of lithium transition element titanates: Li₂FeTiO₄ and Li₂MnTiO₄. Both materials consist of 10–20 nm particles embedded in a conductive carbon coating. We show that not the coating but the small particle size is decisive for materials’ activity. Li₂FeTiO₄ shows a stable reversible capacity of up to 123 mA hg⁻¹ at C/20 and 60 °C which is 83% of the theoretical value for exchange of 1 electron (148 mA hg⁻¹). Li₂MnTiO₄ could only be prepared in a nanosized form that contained about 30% of impurities. The capacity of the whole material (including impurities) is comparable to that of Li₂FeTiO₄ but the cycling stability is much poorer. In contrast to the Fe and Mn analogues, the third member of the titanate family, Li₂NiTiO₄, shows a good electrochemistry even when the particle size is much larger (about 100 nm). During initial cycles at C/10 and 60 °C, exchange of more than 1 electron per compound formula has been observed. The cycling stability at high temperatures, however, is poor.