Stabilization of 6H-Hexagonal SrMnO3 Polymorph by Al2O3 insertion

We demonstrate the structural evolution of polymorphic phases in Al₂O₃-inserted SrMnO₃ ceramics synthesized by solid state reaction. While the 4H-hexagonal phase is predominant in pure SrMnO₃ ceramics, a small amount of 6H-hexagonal polymorph is identified in addition to the primary 4H-hexagonal SrMnO₃ and the secondary hexagonal SrAl₂O₄ phases in the as-sintered ceramics, evidenced by x-ray diffraction and subsequent Rietveld refinement analyses. The existence of the 6H-hexagonal SrMnO₃ phase is corroborated using Raman spectroscopy. The chemical compositions and electronic structures of the Al₂O₃-inserted SrMnO₃ compounds are also examined using energy dispersive spectroscopy and x-ray photoelectron spectroscopy, respectively. The first-principles calculations reveal that there is no clear difference between the total energies of 4H- and 6H-hexagonal polymorphs regardless of the presence/absence of Sr and oxygen vacancies. Possible origins are discussed with the estimation of actual strain based on the refined lattice parameter of 6H SrMnO₃.     

Selective temporal filtering and its application to hand gesture recognition

In temporal data analysis, noisy data is inevitable in both testing and training. This noise can seriously influence the performance of the temporal data analysis. To address this problem, we propose a novel method, termed Selective Temporal Filtering that builds a noise-free model for classification during training and identifies key-feature vectors that are noise-filtered data from the input sequence during testing. The use of these key-feature vectors makes the classifier robust to noise within the input space. The proposed method is validated on a synthetic-dataset and a database of American Sign Language. Using key-feature vectors results in robust performance with respect to the noise content. Futhermore, we are able to show that the proposed method not only outperforms Conditional Random Fields and Hidden Markov Models in noisy environments, but also in a well-controlled environment where we assume no significant noise vectors exist.     

Development of a new analytical tool to design hierarchical truss beams for natural frequency

A set of recursive equations are introduced for optimum design of a wide range of hierarchical truss beams to satisfy a minimum required natural frequency. The design equations are based on a general analytical solution, which are derived based on a critical dimensional analysis. A practical example is examined in both 2D and 3D spaces, which promises substantial mass reduction, as much as 99%, when using high order hierarchical truss beams. The results are verified by numerical evaluation of three case studies. The approach looks also very promising to design nanostructures when it comes to the problems associated with vibration.     

Change of Writing Style with Time

This study investigates the writing stylechange of two Turkish authors, Çetin Altanand Yaar Kemal, in their old and newworks using respectively their newspapercolumns and novels. The style markers are thefrequencies of word lengths in both text andvocabulary, and the rate of usage of mostfrequent words. For both authors, t-tests andlogistic regressions show that the length ofthe words in new works is significantly longerthan that of the old. The principal componentanalyses graphically illustrate the separationbetween old and new texts. The works arecorrectly categorized as old or new with 75 to100% accuracy and 92% average accuracy usingdiscriminant analysis-based cross validation. The results imply higher time gap may havepositive impact in separation andcategorization. For Altan a regressionanalysis demonstrates a decrease in averageword length as the age of his column increases. One interesting observation is that for oneword each author has similar preference changesover time.     

Soluble soybean polysaccharide/TiO2 nanocomposites: Biological activity,release behavior,biodegradability, and biosafety

This study aimed to produce and characterize eco-friendly SSPS nanocomposites incorporated with various concentrations of TiO₂ nanoparticles (NPs) (1%, 3%, and 7%). The antimicrobial activity of the nanocomposite films against five strains of pathogenic bacteria was examined. Salmonella typhi PTCC 1609 was the most sensitive species to TiO₂ NPs at concentrations equal to the synthetic antibiotic. The migration of TiO₂ to ethanol and acetic acid, as two food simulants increased when the initial nano-TiO₂ content increased. The release profiles for TiO₂ in two simulants of ethanol and acetic acid indicated a non-Fickian release, and the release kinetics were concentration-dependent. SSPS/TiO₂ nanocomposites degraded easily and thus have the potential to be applied as an eco-friendly packaging system. Oral administration of doses of 1, 12.5, 25, 50, and 75 mg/kg TiO₂ revealed that the dose of 50 and 75 mg/kg increased malondialdehyde (p < .001) concentration in the liver tissue. In addition, it decreased glutathione (p < .001) concentration in the liver tissue.     

Performance Evaluation of Supervised Machine Learning Techniques for Efficient Detection of Emotions from Online Content

Emotion detection from the text is a challenging problem in the text analytics. The opinion mining experts are focusing on the development of emotion detection applications as they have received considerable attention of online community including users and business organization for collecting and interpreting public emotions. However, most of the existing works on emotion detection used less efficient machine learning classifiers with limited datasets, resulting in performance degradation. To overcome this issue, this work aims at the evaluation of the performance of different machine learning classifiers on a benchmark emotion dataset. The experimental results show the performance of different machine learning classifiers in terms of different evaluation metrics like precision, recall ad f-measure. Finally, a classifier with the best performance is recommended for the emotion classification.     

Electromechanical properties of ternary BiFeO<Subscript>3</Subscript>−0.35BaTiO<Subscript>3</Subscript>–BiGaO<Subscript>3</Subscript> piezoelectric ceramics

In the present work, composition dependent crystal structure, ferroelectric, piezoelectric, and temperature dependent dielectric properties of the BiGaO₃-modified (1–x)(0.65Bi_1.05FeO₃–0.35BaTiO₃) (BFBT35–xBG, where x?=?0.00–0.03) lead-free ceramics were systematically investigated by solid-state reaction method, followed by water quenching process. The substitution of BG successfully diffuses into the lattice of the BFBT ceramics, without changing the pseudo-cubic structure of the samples. The scanning electron microscopy (SEM) results revealed that the average grain size was increased with BG-content in BFBT system. The BFBT–xBG ceramics showed a maximum in permittivity (?_max) at temperatures (T_max) above 500 °C in the compositional range of 0.00?≤?x?≤?0.03. The electro-strain is measured to be 0.125% (d^*₃₃ ~ 250 pm/V) under unipolar fields (5 kV/mm) for BFBT–0.01BG ceramics. The same composition (x?=?0.01), large static piezoelectric constant (d₃₃ ~ 165 pC/N) and electromechanical coupling factor (k_p ~ 25%) were obtained. The above investigated characterizations suggests that BFBT–BG material is favorable for piezoelectric and high temperature applications.     

Evolution of ferroelectric and piezoelectric response by heat treatment in pseudocubic BiFeO<Subscript>3</Subscript>–BaTiO<Subscript>3</Subscript> ceramics

Heat treatment of ceramics is an important process to tailor the fine electromechanical properties. To explore the criteria for optimized heat treatment in a perovskite structure of (1–x)Bi_1.05FeO₃–xBaTiO₃ (BF–BT100x) system, the structural phase relation, ferroelectric and piezoelectric response of BF–BT36 and BF–BT40 ceramics prepared by furnace cooling (FC) and quenching process were investigated. The X-ray diffraction examination showed single pseudocubic perovskite structure for all the ceramics. The homogenous microstructure was obtained for all ceramics with relatively large grain size in the furnace cooled samples. Well saturated ferroelectric hysteresis loops and enhanced piezoelectric constant (d₃₃?=?97 pC/N) were achieved by quenching process. Dielectric curve of BF–BT36 showed large dielectric constant at its Curie temperature, however, BF–BT40 showed diffused relaxor-like dielectric anomalies. Quenched BF–BT36 samples showed typical butterfly like field induced strain curves, however negative strain decreased in BF–BT40 ceramics. From these investigated study, it is observed that BF–BT ceramics are very sensitive to the heat treatment process (furnace cooling and quenching) on the dielectric, electromechanical properties.