Dielectric,ferroelectric, and energy storage properties in dysprosium doped sodium bismuth titanate ceramics

In this work, Na_0.5(Bi_1-xDy_x)_0.5TiO₃ (0?≤?x?≤?15%) ceramics were prepared via solid state reaction method and were characterized. A stable and pure perovskite phase was revealed by X-ray diffraction analysis for all compositions and a symmetry change from rhombohedral to orthorhombic phase was detected beyond 10% of Dy substitution. The incorporation of Dy³⁺ into Sodium Bismuth Titanate (Na_0.5Bi_0.5TiO₃) matrix allows a substantial decrease of the coercive field, an increase in the resistivity, and leads to a high stability of the dielectric permittivity (??/?_(150?°C) ≤?±?15%) over a wide temperature range. Furthermore, this system was found to exhibit improved energy storage properties at high temperatures with a maximum energy density of 1.2?J/cm³ obtained for 2%Dy composition at 200?°C. The obtained results are very promising for energy storage capacitors operating at high temperatures.     

Voice assessments for detecting patients with Parkinson’s diseases using PCA and NPCA

In this study, we wanted to discriminate between two groups of people. The database used in this study contains 20 patients with Parkinson’s disease and 20 healthy people. Three types of sustained vowels (/a/, /o/ and /u/) were recorded from each participant and then the analyses were done on these voice samples. Firstly, an initial feature vector extracted from time, frequency and cepstral domains. Then we used linear and nonlinear feature extraction techniques, principal component analysis (PCA), and nonlinear PCA. These techniques reduce the number of parameters and choose the most effective acoustic features used for classification. Support vector machine with its different kernel was used for classification. We obtained an accuracy up to 87.50 % for discrimination between PD patients and healthy people.     

Multiclass classification of Parkinson’s disease using different classifiers and LLBFS feature selection algorithm

Since approximately 90% of the people with PD (Parkinson’s disease) suffer from speech disorders including disorders of laryngeal, respiratory and articulatory function, using voice analysis disease can be diagnosed remotely at an early stage with more reliability and in an economic way. All previous works are done to distinguish healthy people from people with Parkinson’s disease (PWP). In this paper, we propose to go further by multiclass classification with three classes of Parkinson stages and healthy control. So we have used 40 features dataset, all the features are analyzed and 9 features are selected to classify PWP subjects in four classes, based on unified Parkinson’s disease Rating Scale (UPDRS). Various classifiers are used and their comparison is done to find out which one gives the best results. Results show that the subspace discriminant reach more than 93% overall classification accuracy.     

Silicene Nanoribbons on an Insulating Thin Film

Silicene, a new 2D material has attracted intense research because of the ubiquitous use of silicon in modern technology. However, producing free-standing silicene has proved to be a huge challenge. Until now, silicene could be synthesized only on metal surfaces where it naturally forms strong interactions with the metal substrate that modify its electronic properties. Here, the authors report the first experimental evidence of silicene nanoribbons on an insulating NaCl thin film. This work represents a major breakthrough, for the study of the intrinsic properties of silicene, and by extension to other 2D materials that have so far only been grown on metal surfaces.     

Fatty acids,sterols, and tocopherols composition in seed oil extracts from four moroccan ecotypes of Ceratonia siliqua L.

Morphological characterization was investigated by agro-morphological criteria related to carob seed size in four different moroccan regions collected in 2018 and 2019. There was no significant difference (p ≤ 0.05) on the seeds lengths and widths. However, a significant difference between seeds thickness and total seeds weight per pod (p ≤ 0.05) were observed between these four populations. The fatty acid, sterol, tocopherol, hydrocarbon, and the unoxygenated composition of carob seed extracts (Ceratonia siliqua L.) were studied. The mean fat yield of the seeds obtained is 1.53%–2.17%, 2.14%–2.15%, 1.61%–1.62%, 1.71%–1.75% for, respectively, the P1 (Meknes), P2 (Fez), P3 (Khemisset), and P4 (Marrakech) in 2018 and 2019. The seed oil was extracted with hexane and the analysis of the fatty fraction was performed by gas chromatography–mass spectrometry (GC–MS). Results show that the major fatty acids for 2018 and 2019 are linoleic acid (61.48%–61.52%, 52.12%–52.14%, 57.76%–58.15%, 61.33%–61.52%), palmitic acid (15.78%–15.81%, 16.44%–16.45%, 19.11%–18.37%, 20.24%–20.32%), oleic acid (11.03%–11.04%, 8.72%–8.82%, 8.51%–8.61%, 8.41%–8.53%), stearic acid (4.35%–3.14%, 5.40%–5.43%, 3.12%–3.13%, 0.96%–1.56%), and cerotic acid (0.62%–0.53%, 4.51%–4.52%, 4.03%–4.06%, 3.84%–3.87%). The unsaturated fatty acids (69.39% in 2018 and 69.68% in 2019) are the most dominant in the four seed extracts compared to the saturated fatty acids. In addition, the oil carob seeds analysis revealed the presence of γ-tocopherol, α-tocopherol and four sterols that included campesterol, stigmasterol, and β-sitosterol. Moreover, the determination of hydrocarbon and un-oxygenated compounds confirmed the existence of major compounds such as heptadecane, 2-methyltriacontane, 1-iodo hexadecane and 1-iodo octadecane. The hierarchical analysis based on the morphological and chromatographic characterization of the seeds allowed the identification of three groups. Consequently, the first group consisted of populations from Marrakesh (P4) and Khemisset (P3), the second group consisted of the P1 from Meknes, and the P2 from Fez constituted the third group.     

Sequencing with limited flexibility

We consider the problem of resequencing a set of prearranged jobs when there is limited resequencing flexibility and sequence-dependent changeover costs. Resequencing flexibility is limited by how far forward or backward a job can shift in the sequence relative to its original position. We show how the problem can be solved using dynamic programming in polynomial time with respect to the number of jobs. We also show how the same solution approach can be extended to problems where sequencing constraints are job specific and to problems where job features, which determine changeover costs, are jointly determined with the job sequence. We provide an integer programming formulation to the resequencing problem whose linear programming relaxation offers a useful lower bound. We also describe a family of decomposition heuristics that are easy to customize to provide desired levels of solution quality and solution time. We document the quality of the lower bound from the linear programming relaxation and the upper bound from the heuristic using numerical results. We also provide numerical results to support managerial insights regarding the value of flexibility. We show that the value of flexibility is of the diminishing kind with most of the benefit realized with relatively limited flexibility. We also show that a balanced allocation of flexibility among forward and backward position shifting is superior to an unbalanced one. More significantly, we show that forward and backward position shifting flexibility are complements with the value of one increasing in the amount of the other. Finally, we apply our solution approach to a real-world case from the automotive industry.     

Investigation of the cationic distribution within the lattice of a series of niobates with tetragonal tungsten bronze structure

Single Crystals of the series K₃Sr₂LnNb₁₀O₃₀ (Ln?=?Lanthanide) have been grown by two different techniques: micro-pulling down and solid state growth. The cationic distribution within the three large cavities of the lattice, determined from the crystal structure resolution, shows that the crystal-chemical formula is depending on the route of preparation. A spectroscopic study has evidenced a broadening of the emission peaks which is also compatible with a disorder distribution of Ln³⁺ ions over 12- and 15-fold cavities.     

Acylated and hydroxylated polyamides derived from l-tartaric acid

A series of polyamides 6,4 were prepared from 1,6-hexanediamine and active esters of 2,3-di-O-acylated l-tartaric acid by polycondensation in solution. Both O-alkoyl and O-benzoyl esters were used as hydroxyl protecting groups. The resulting acylated polytartaramides were found to be semicrystalline polymers with T_m between 100 and 200 °C and T_g slightly above 100 °C. Controlled hydrolysis of the ester side group led to the preparation of poly(hexamethylene l-tartaramide)s with different content in free hydroxyl groups. These polyamides continue being crystalline but their properties largely differ from those displayed by their parent acylated polymers.