Temperature Stable Dielectric Behavior of Sol–Gel Derived Compositionally Graded SrTiO3/Na0.5Bi0.5TiO3/SrTiO3 Thin Films

Polycrystalline sol–gel‐derived SrTiO₃/Na_0.5Bi_0.5TiO₃/SrTiO₃ (ST/NBT/ST) thin films were designed to achieve the electrical isolation of the NBT, and to mediate the temperature dependency of the dielectric properties. Proper thermal annealing of particulate phase enabled us to achieve compositionally graded elemental profiles between individual ST and NBT layers. The dielectric and ferroelectric properties were investigated with respect to the electrical behavior of the monophasic ST and NBT thin films. The dielectric characteristics of the multilayer thin film were marked by a temperature stable behavior (temperature coefficient of dielectric constant of 780 ppm/°C) in the measured ?50°C to 200°C range, frequency‐independent response at room temperature and improved dielectric loss characteristics compared with the NBT; however, on the expense of decreased permittivity and a reduced ferroelectric stability. Nevertheless, stable dielectric properties were achieved and properties of multilayer may well be exploited in functional devices that demand insensitive operation over wide temperature and frequency ranges.     

Extensions of sweep surface constructions

Sweeping is a very important, powerful, and widespread method in geometric modelling. In this paper, we consider only sweep surfaces, generated by sweeping one curve (cross-section) along the other curve (trajectory), and their existing construction methods: the Frenet frame method, the discrete approach, the offset method, and the projection technique. All these methods are extended so that they now include non-homogeneous scaling and twisting of the cross-section, which enable the generation of complex twisted-profiled sweep surfaces.     

Supply-chain transparency within industrialized construction projects

This paper addresses those issues relating to the integration of information flows in relation to material management throughout the construction industry supply-chain. Based on a case study, it shows how to bridge any gaps between those information systems used within the design, prefabrication, and on-site construction processes.     

Three Important Points that Relate to Improving the Hot Workability of Ledeburitic Tool Steels

In this article, the importance of selecting the right process parameters for ledeburitic tool steels, i.e., casting temperature, cooling rate, and soaking temperature, which is needed to improve their intrinsic hot workability, is presented. The results were obtained from investigations in industrial practice and in the laboratory. It was found that inappropriate selection of these process parameters results in the occurrence of carbides that are not usually present in these types of steels, in terms of type, shape, fractions, and their distribution that decreases the steels?? hot workability. In particular, a casting temperature that is too high and cooling rates that are too low result in the additional precipitation of carbides, which are not common in these steels, leading to cracking, predominately along these carbide stringers and consequently to a deterioration of the hot workability and the properties of the final products. It was also found that by selecting the proper soaking conditions, it is possible to decrease the negative influence of previous processing parameters on the hot workability.     

Preparation of cadmium telluride nanoparticles from aqueous solutions by sonochemical method

Cadmium telluride nanoparticles with sizes between 8 and 13 nm have been synthesized via a sonochemical route using cadmium sulfate hydrate (CdSO₄·8/3H₂O), cadmium chloride (CdCl₂) and elemental Te as precursors and aqueous solutions of NaOH and EDTA as solvents. The qualitative characterization and estimation of nanoparticle size were carried out by using X-ray powder diffraction (XRD). The morphology of nanoparticles was analyzed by transmission electron microscopy (TEM). Changes of physical and chemical properties of the prepared CdTe nanoparticles at increased temperature were studied by thermal analysis (TGA, SDTA). A probable mechanism for the sonochemical formation of CdTe is proposed.     

Culturomics meets random fractal theory: insights into long-range correlations of social and natural phenomena over the past two centuries

Culturomics was recently introduced as the application of high-throughput data collection and analysis to the study of human culture. Here, we make use of these data by investigating fluctuations in yearly usage frequencies of specific words that describe social and natural phenomena, as derived from books that were published over the course of the past two centuries. We show that the determination of the Hurst parameter by means of fractal analysis provides fundamental insights into the nature of long-range correlations contained in the culturomic trajectories, and by doing so offers new interpretations as to what might be the main driving forces behind the examined phenomena. Quite remarkably, we find that social and natural phenomena are governed by fundamentally different processes. While natural phenomena have properties that are typical for processes with persistent long-range correlations, social phenomena are better described as non-stationary, on–off intermittent or Lévy walk processes.     

Dual-task performance in multimodal human-computer interaction: a psychophysiological perspective

This paper examines the psychophysiological effects of mental workload in single-task and dual-task human-computer interaction. A mental arithmetic task and a manual error correction task were performed both separately and concurrently on a computer using verbal and haptic input devices. Heart rate, skin conductance, respiration and peripheral skin temperature were recorded in addition to objective performance measures and self-report questionnaires. Analysis of psychophysiological responses found significant changes from baseline for both single-task and dual-task conditions. There were also significant psychophysiological differences between the mental arithmetic task and the manual error correction task, but no differences in questionnaire results. Additionally, there was no significant psychophysiological difference between performing only the mental arithmetic task and performing both tasks at once. These findings suggest that psychophysiological measures respond differently to different types of tasks and that they do not always agree with performance or with participants’ subjective feelings.     

Intelligent System for Diagnosis of Erythema Migrans

Lyme borreliosis is the most common human tick-borne infectious disease of the Northern Hemisphere. One of the first signs of the disease is erythema migrans, a skin lesion that appears within days to weeks after an infected tick bite. In this article, a novel intelligent system for erythema migrans recognition is presented based on image and text information, applicable for individual and clinical web-based use. Novelties of our approach include a combination of visual and textual attributes, a new combination of visual attributes (geometrical, color, and Gabor-filter based), and a new algorithm for calculation of color-based attributes. Procedurally, the intelligent system for erythema migrans recognition integrated in a web-based application facilitates provisional diagnosis of erythema migrans in the general population and assists general medical practitioners in their decisions. Several classification methods—Naïve Bayes, Support Vector Machine, Adaboost, and Random forest—were tested in order to achieve improved performance.     

The pathology of heuristic search in the 8-puzzle

In practice, an incomplete heuristic search nearly always finds better solutions if it is allowed to search deeper, i.e. expand and heuristically evaluate more nodes in the search tree. On the rare occasions when searching deeper is not beneficial, a curious phenomenon called ‘search pathology’ occurs. In this article, we study the pathology and gain of a deeper search of the minimin algorithm in the 8-puzzle, a domain often used for evaluating single-agent search algorithms. We have analysed the influence of various properties of the search tree and the heuristic evaluation function on the gain and the pathology. In order to investigate a broad range of the properties, the original 8-puzzle was extended with diagonal moves, yielding a larger variety of search trees. It turned out that in the 8-puzzle, a substantial proportion of the solvable positions is pathological under various parameters. More importantly, the search parameters that enable the highest gains are quite consistent in pathological and non-pathological positions alike, thus pointing to potentially successful search strategies.