A synthetic high-voltage power line insulator images dataset.

High-voltage power line insulators are crucial for safe and efficient electricity transmission. However, real-world image limitations, particularly regarding dirty insulator strings, delay the development of robust algorithms for insulator inspection. This dataset addresses this challenge by creating a novel synthetic high-voltage power line insulator image database. The database was created using computer-aided design softwares and a game development engine. Publicly available CAD models of high-voltage towers with the most common insulator types (polymer, glass, and porcelain) were imported into the game engine. This virtual environment allowed for the generation of a diverse dataset by manipulating virtual cameras, simulating various lighting conditions, and incorporating different backgrounds such as mountains, forests, plantation, rivers, city and deserts. The database comprises two main sets: The Image Segmentation Set, which includes 47,286 images categorized by insulator material (ceramic, polymeric, and glass) and landscape type (mountains, forests, plantation, rivers, city and deserts). Moreover, the Image Classification Set that contains 14,424 images simulating common insulator string contaminants: salt, soot, bird excrement, and clean insulators. Each contaminant category has 3,606 images divided into 1,202 images per insulator type. This synthetic database offers a valuable resource for training and evaluating machine learning algorithms for high-voltage power line insulator inspection, ultimately contributing to enhanced power grid maintenance and reliability.

Signature of excitonic insulators in phosphorene nanoribbons.

Phosphorene is a recently developed two-dimensional (2D) material that has attracted tremendous attention because of its unique anisotropic optical properties and quasi-one-dimensional (1D) excitons. We use first-principles calculations combined with the maximally localized Wannier function tight binding Hamiltonian and Bethe-Salpeter equation (BSE) formalism to investigate quasiparticle effects of 2D and quasi-1D blue and black phosphorene nanoribbons. Our electronic structure calculations shows that both blue and black monolayered phases are semiconductors. On the other hand black phosphorene zigzag nanoribbons are metallic. Similar behavior is found for very thin blue phosphorene zig-zag and armchair nanoribbon. As a general behavior, the exciton binding energy decreases as the ribbon width increases, which highlights the importance of quantum confinement effects. The solution of the BSE shows that the blue phosphorene monolayer has an exciton binding energy four times higher than that of the black phosphorene counterpart. Furthermore, both monolayers show a different linear optical response with respect to light polarization, as black phosphorene is highly anisotropic. We find a similar, but less pronounced, optical anisotropy for blue phosphorene monolayer, caused exclusively by the quasi-particle effects. Finally, we show that some of the investigated nanoribbons show a spin-triplet excitonic insulator behavior, thus revealing exciting features of these nanoribbons and therefore provides important advances in the understanding of quasi-one dimensional phosphorus-based materials.

Drone-Robot to Clean Power Line Insulators.

The inspection and maintenance of transmission systems are necessary for their proper functioning. In this way, among the line's critical points are the insulator chains, which are responsible for providing insulation between conductors and structures. The accumulation of pollutants on the insulator surface can cause failures in the power system, leading to power supply interruptions. Currently, the cleaning of insulator chains is performed manually by operators who climb towers and use cloths, high-pressure washers, or even helicopters. The use of robots and drones is also under study, presenting challenges to be overcome. This paper presents the development of a drone-robot for cleaning insulator chains. The drone-robot was designed to identify insulators by camera and perform cleaning through a robotic module. This module is attached to the drone and carries a battery-powered portable washer, a reservoir for demineralized water, a depth camera, and an electronic control system. This paper includes a literature review on the state of the art related to strategies used for cleaning insulator chains. Based on this review, the justification for the construction of the proposed system is presented. The methodology used in the development of the drone-robot is then described. The system was validated in a controlled environment and in field experimental tests, with the ensuing discussions and conclusions formulated, along with suggestions for future work.

Double resonance between corner states in distinct higher-order topological phases.

Recent studies have shown that higher-order topologies in photonic systems lead to a robust enhancement of light-matter interactions. Moreover, higher-order topological phases have been extended to systems even without a band gap, as in Dirac semimetals. In this work, we propose a procedure to simultaneously generate two distinctive higher-order topological phases with corner states that allow a double resonant effect. This double resonance effect between the higher-order topological phases, was obtained from the design of a photonic structure with the ability to generate a higher-order topological (HOTI) insulator phase in the first bands and a higher-order Dirac half-metal phase (HODSM). Subsequently, using the corner states in both topological phases, we tuned the frequencies of both corner states such that they were separated in frequency by a second harmonic. This idea allowed us to obtain a double resonance effect with ultra-high overlap factors, and a considerable improvement in the nonlinear conversion efficiency. These results show the possibility of producing a second-harmonic generation with unprecedented conversion efficiencies in topological systems with simultaneous HOTI and HODSM phases. Furthermore, since the corner state in the HODSM phase presents an algebraic 1/rdecay, our topological system can be helpful in experiments about the generation of nonlinear Dirac-ligh-matter interactions.

Optimized EWT-Seq2Seq-LSTM with Attention Mechanism to Insulators Fault Prediction.

Insulators installed outdoors are vulnerable to the accumulation of contaminants on their surface, which raise their conductivity and increase leakage current until a flashover occurs. To improve the reliability of the electrical power system, it is possible to evaluate the development of the fault in relation to the increase in leakage current and thus predict whether a shutdown may occur. This paper proposes the use of empirical wavelet transform (EWT) to reduce the influence of non-representative variations and combines the attention mechanism with a long short-term memory (LSTM) recurrent network for prediction. The Optuna framework has been applied for hyperparameter optimization, resulting in a method called optimized EWT-Seq2Seq-LSTM with attention. The proposed model had a 10.17% lower mean square error (MSE) than the standard LSTM and a 5.36% lower MSE than the model without optimization, showing that the attention mechanism and hyperparameter optimization is a promising strategy.

Band Polarization Effect on the Kondo State in a Zigzag Silicene Nanoribbon.

Using the Numerical Renormalization Group method, we study the properties of a quantum impurity coupled to a zigzag silicene nanoribbon (ZSNR) that is subjected to the action of a magnetic field applied in a generic direction. We propose a simulation of what a scanning tunneling microscope will see when investigating the Kondo peak of a magnetic impurity coupled to the metallic edge of this topologically non-trivial nanoribbon. This system is subjected to an external magnetic field that polarizes the host much more strongly than the impurity. Thus, we are indirectly analyzing the ZSNR polarization through the STM analysis of the fate of the Kondo state subjected to the influence of the polarized conduction electron band. Our numerical simulations demonstrate that the spin-orbit-coupling-generated band polarization anisotropy is strong enough to have a qualitative effect on the Kondo peak for magnetic fields applied along different directions, suggesting that this contrast could be experimentally detected.

DFT-1/2 method applied to 2D topological insulators: fluorinated and hydrogenated group-IV honeycomb systems.

We present a computationally efficient and accurate methodology to computeZ2topological invariants for systems without inversion symmetry including quasiparticle (QP) effects within the density functional theory (DFT)-1/2 method. The Wannier charge center evolution is applied to compute theZ2topological invariant and investigate the topological properties of group-IV graphene-like systems, graphene, silicene, germanene and stanene, whose inversion symmetry is broken by simultaneous functionalization with hydrogen and fluorine atoms. Different atomic arrangements are studied. The systems are stable with cohesive energy decreasing along the row from carbon to tin. A similar trend is observed for band gaps. The resulting topological invariants are compared with values obtained within conventional DFT and using a hybrid exchange-correlation functional. The variation of the results with the treatment of exchange and correlation demonstrates the importance of QP corrections for the prediction of the topological or trivial character.

Spin-Polarized Tunable Photocurrents.

Harnessing the unique features of topological materials for the development of a new generation of topological based devices is a challenge of paramount importance. Using Floquet scattering theory combined with atomistic models we study the interplay among laser illumination, spin, and topology in a two-dimensional material with spin-orbit coupling. Starting from a topological phase, we show how laser illumination can selectively disrupt the topological edge states depending on their spin. This is manifested by the generation of pure spin photocurrents and spin-polarized charge photocurrents under linearly and circularly polarized laser illumination, respectively. Our results open a path for the generation and control of spin-polarized photocurrents.

Electric-field-generated topological states in a silicene nanotube.

Applying an electric field perpendicular to the axis of a silicene armchair nanotube allows us to numerically study the formation of eight topological edge states as silicene's intrinsic spin-orbit gap is closed by the sublattice-staggered electrostatic potential created by the electric field. Following their evolution with electric field, it is revealed that, at very small fields, these eight states are very broad, spin-locked, and sublattice constrained, inheriting their properties from the K and K' states in a silicene two-dimensional honeycomb lattice. Four of those states are centered at the very top of the nanotube and the other four states are centered at the very bottom. As the field increases, each state starts to become narrower and to spread its spectral weight to the other sublattice. With further increase of the field, each state starts to spatially split, while the sublattice spreading continues. Once the spectral weight of each state is distributed evenly among both sublattices, the state has also effectively split into two spatially disconnected parts, after which, further increasing of the field will spread apart the two halves, moving them to the lateral regions of the nanotube, at the same time that the state halves become narrower. This is consistent with the formation of topological edge states, which delimit four ribbon-like topologically different regions: top and bottom topologically trivial 'ribbons' (where the electric field has induced a topological phase transition) that are adjacent to two topologically nontrivial 'ribbons' located at opposing sides of the nanotube. We also briefly access the possibility of observing these edge states by calculating the electronic properties for an electric field configuration that can be more readily produced in the laboratory.

EFECTO DE LA ADICIÓN DE MATERIALES RECICLABLES EN LA MASILLA PARA CONSTRUCCIÓN LIVIANA RESPECTO A LA CAPACIDAD CALORÍFICA, AISLAMIENTO TÉRMICO Y ACÚSTICO / EFFECT OF THE ADDITION OF RECYCLABLE MATERIALS IN THE LIGHTWEIGHT CONSTRUCTION MASTIC REGARDING THE CALORIFYING CAPACITY, AND THERMAL AND ACOUSTIC INSULATION

Este trabajo discute los resultados de la investigación experimental conducida para estudiar la inclusión de materiales reciclables como cascarilla de arroz, poliestireno expandido (icopor) y tereftalato de polietileno ­PET­ en la masilla para construcción liviana empleada para la fabricación de placas de Drywall como respuesta a la minimización del impacto ambiental y al aprovechamiento de las propiedades de los materiales desechados que son nuevamente introducidos en procesos productivos con el fin de obtener baja conductividad térmica, alta capacidad calorífica, alta capacidad de absorción sonora y cumplir con la normativa internacional para materiales de construcción; para ello se realizaron pruebas para medir cuatro propiedades como son el aislamiento térmico, capacidad calorífica y pruebas físico-mecánicas (resistencia a la flexión y resistencia a la tracción de clavo) por medio de probetas, teniendo en cuenta la normativa ASTM C 1396/C1396M-04 y ASTM C473-03, mientras que para la prueba de aislamiento acústico se utilizaron las normas ISO 16283-1 e ISO 717-1; los resultados obtenidos se procesaron aplicando un análisis estadístico multivariado empleando el software Statgraphics Centurion XVII que estableció los valores máximos y mínimos, la correlación de Pearson y ordinal de Spearman como método de análisis para el reporte del material más eficiente respecto a las cuatro propiedades medidas. La cascarilla de arroz, sustituyendo en un 60 % el peso del yeso en la masilla original, reportó los mejores resultados en cada una de las cuatro pruebas realizadas a lo largo de la investigación; de esta manera se confirma que es un material adecuado para la implementación en procesos de construcción liviana dado que demuestra que los materiales reciclables son eficientes y además poseen propiedades específicas como resistencia, liviandad y flexibilidad que le dan un valor agregado para ser utilizados nuevamente como reemplazo de materiales tradicionales.

This paper discusses the results of the experimental research conducted to study the inclusion of recyclable materials such as rice husks, expanded polystyrene (Styrofoam), and polyethylene terephthalate (PET) in the mastic for lightweight construction used for the manufacture of Drywall plates in response to the minimization of the environmental impact, and the use of the properties of discarded materials that are, once again, introduced in productive processes to obtain low thermal conductivity, high heat capacity, high sound absorption capacity and that comply with international standards for construction materials. For this purpose, tests to measure four properties such as Thermal Insulation, Calorific Capacity and Physical-Mechanical Testing (Flexural Resistance and Nail Tensile Strength) were carried out by means of test pieces taking into account the ASTM C1396 / C1396M - 04 and ASTM C473 - 03, while ISO 16283-1 and ISO 717-1 were used for the acoustic insulation test. The results obtained were processed by applying a multivariate statistical analysis using the Statgraphics Centurion XVII-2015 software that established the maximum and minimum values, Pearson's correlation and Spearman's ordinal as the analysis method for reporting the most efficient material regarding the four measured properties. Rice husk, replacing by 60% the weight of plaster in the original mastic, reported the best results in each of the four tests carried out throughout the research. In this way, it is confirmed that it is a suitable material for the implementation in lightweight construction processes as it shows that recyclable materials are efficient and also have specific properties such as strength, lightness and flexibility that give an added value to be used again as a replacement of traditional materials.