Reflective low-sideband plasmonic structural colors

It is demonstrated experimentally that an aluminum (Al) nanowire grating structure on silicon substrates can produce low-side-band monochromatic peak when it reflects colored light in the transverse magnetic (TM) mode. The central wavelength of the reflection is shown to be sensitive to the incident angle, which leads to significant color shifts. Formation of the monochromatic peak is attributed to the surface plasmon resonance on the interface between Al and air, together with remarkable diffraction at shorter wavelengths and strong Fabry-Perot (F-P) resonance absorption by Al-surrounding nano-cavities and silicon substrate at longer wavelengths. In contrast, reflection in transverse electric (TE) mode does not show distinct wavelength selectivity due to the cut-off effect of the nano-cavities. The outstanding characters of the proposed structure with polarization dependence, high sensitivity to incident angle, high color rendering facilitate more compact and sophisticated color-filter-based devices for displays, anti-counterfeit, and sensing applications. In addition, the two-dimensional structure with thin grating thickness and high duty ratio tolerance is relatively easy for fabrication

Implementación de artificial Bee Colony para controlador bilineal en actuadores SMA

Este trabajo consiste en la implementación del algoritmo ABC (Artificial Bee Colony) para buscar las mejores ganancias de un controlador PID Bilineal para actuadores SMA (Shape memory alloy). A continuación se realiza una breve descripción de los puntos más importantes de este trabajo. El algoritmo que voy a utilizar en este trabajo se denomina algoritmo ABC. Sus siglas traducidas al español significan colonia artificial de abejas. Como su nombre indica, su desarrollo se basa en el comportamiento de búsqueda de alimento de las abejas comunes. Es un algoritmo que se ha desarrollado recientemente y su uso no es tan común, aunque en estos últimos años muchos investigadores han empezado a utilizarlo por su precisión y fiabilidad. El controlador PID bilineal consiste en un regulador clásico PID al cual se le añade un componente bilineal. Este tipo de reguladores se usa en control de sistemas no lineales para compensar la no-linealidad de una planta. De este modo, facilita el modelado y el control de una función de transferencia no lineal de un sistema, que en el caso que aquí ocupa va a ser un actuador SMA. De acuerdo a esto, las ganancias que debe encontrar el algoritmo ABC para el controlador son: Kp, Ki, Kd (por parte del PID) y Kb (por parte del bilineal). El actuador SMA (Shape Memory Alloy) es un dispositivo compuesto por una aleación metálica de níquel y titanio que se caracteriza por la propiedad de que puede “recordar” y volver a su forma original tras una deformación. Hasta el momento es un material no muy conocido y su uso no está tan extendido, aunque se espera que en un futuro cercano esté implementado en los aparatos de los distintos sectores, como el biomédico o el aeronáutico. Los resultados experimentales muestran que se ha implementado satisfactoriamente el algoritmo y el optimizador es capaz de encontrar parámetros adecuados para el control bilineal cuando este se aplica para un modelo de planta que simula el comportamiento de actuador SMA.This work consists of the implementation of the ABC (Artificial Bee Colony) algorithm in order to optimize the parameters of a Bilinear PID controller for SMA (Shape Memory Alloy) actuators. A brief description about the most important aspects of the project is given in the following paragraphs. The algorithm that is the core of the optimization method is the ABC. It is based on the behavior of the common bees when searching for food. This technique is quite new and not very common among researchers. However, in the last years, its use has been increased due to its good performance regarding accuracy and reliability. The Bilinear PID controller is based on a classic PID regulator with a bilinear term. This type of controller is used in non-linear system to linearize the non-linear plant. After that, it is easier to model and control the linearized system. In this case, the non-linear model is a SMA actuator. The gains to be optimized by the ABC-based technique are Kp, Ki, Kd (PID) and Kb (bilinear term). The SMA actuator is a device formed by a metal alloy of nickel and titanium which is characterized by the property that it can "remember" and return to its original shape after deformation. The use of this material is not widespread, although it is expected that in the near future it will be implemented in devices of different sectors such as biomedical and aeronautics. The experimental results show that the algorithm has been successfully implemented and the optimizer computes adequate parameters for the bilinear controller when it is applied to a plant model that simulates the behavior of a SMA actuator.Ingeniería Electrónica Industrial y Automátic

Warranty menu design for a two-dimensional warranty

Fierce competitions in the commercial product market have forced manufacturers to provide customer-friendly warranties with a view to achieving higher customer satisfaction and increasing the market share. This study proposes a strategy that offers customers a two-dimensional warranty menu with a number of warranty choices, called a flexible warranty policy. We investigate the design of a flexible two-dimensional warranty policy that contains a number of rectangular regions. This warranty policy is obtained by dividing customers into several groups according to their use rates and providing each group a germane warranty region. Consumers choose a favorable one from the menu according to their usage behaviors. Evidently, this flexible warranty policy is attractive to users of different usage behaviors, and thus, it gives the manufacturer a good position in advertising the product. When consumers are unaware about their use rates upon purchase, we consider a fixed two-dimensional warranty policy with a stair-case warranty region and show that it is equivalent to the flexible policy. Such an equivalence reveals the inherent relationship between the rectangular warranty policy, the L-shape warranty policy, the step-stair warranty policy and the iso-probability of failure warranty policy that were extensively discussed in the literature

Physics-Informed Neural Networks for Prognostics and Health Management of Lithium-Ion Batteries

For Prognostics and Health Management (PHM) of Lithium-ion (Li-ion) batteries, many models have been established to characterize their degradation process. The existing empirical or physical models can reveal important information regarding the degradation dynamics. However, there are no general and flexible methods to fuse the information represented by those models. Physics-Informed Neural Network (PINN) is an efficient tool to fuse empirical or physical dynamic models with data-driven models. To take full advantage of various information sources, we propose a model fusion scheme based on PINN. It is implemented by developing a semi-empirical semi-physical Partial Differential Equation (PDE) to model the degradation dynamics of Li-ion batteries. When there is little prior knowledge about the dynamics, we leverage the data-driven Deep Hidden Physics Model (DeepHPM) to discover the underlying governing dynamic models. The uncovered dynamics information is then fused with that mined by the surrogate neural network in the PINN framework. Moreover, an uncertainty-based adaptive weighting method is employed to balance the multiple learning tasks when training the PINN. The proposed methods are verified on a public dataset of Li-ion Phosphate (LFP)/graphite batteries.Comment: 14 pages, 10 figure

Broad bandwidth waveguide polarizer via grating mediated mode conversion

A polarization beam splitter (PBS) based on a four-layer slab waveguide is proposed, where a sub-wavelength grating is embedded between the waveguide core and the cladding. This grating not only affords Bragg momentum to tune the propagation constant of guiding modes but also converts the forward zero-order waveguide mode to the backward first one for a specific polarization. Thus, the incident light with polarization that satisfies the phase-matching condition is highly reflected in the waveguide, while other light with orthogonal polarization keeps intact and passes through it efficiently. Numerical simulations show that one can make the compact PBS for both polarizations with an extinction ratio higher than 35 dB, a waveband larger than 80 nm, a grating period tolerance of 20 nm, and a waveguide height tolerance of 80 nm. The revealed mode conversion mechanism via the sub-wavelength grating enriches the design of PBSs for integrated silicon waveguide chips

Reliability modelling of infrastructure load-sharing systems with workload adjustment

Motivated by the need to support effective asset management of infrastructure systems, this paper presents a novel reliability model for a load-sharing system where the operator can adjust component work load to balance system degradation. The operator intervention effect, combined with other system complexities, makes modeling reliability interesting and challenging. We first develop cost modeling for a load-sharing system that has experienced operational service at the time of analysis. The system replacement process is modeled as a delayed renewal process for which the expected operational cost of the system is derived. A numerical algorithm is proposed to compute the cost, and the error bound is shown to be of order O(n−1). Next, we extend modeling to consider multiple heterogeneous systems located at different sites within the infrastructure network. Heterogeneities here refer to possible cross-site differences in the operating environments and the operators’ actions. When the heterogeneities are observable, we model as covariates; otherwise, we model as random effects. Statistical inference methods are developed for the proposed models. An example using real data from a water utility illustrates the logical model behavior given parameter choices as well as showing how analysis might inform asset management

Highly tunable polarized chromatic plasmonic films based on sub-wavelength grating templates

A kind of polarized chromatic plasmonic film is proposed based on subwavelength grating structure, which enables “blue transmission” for the transverse electric light and “red transmission” for the transverse magnetic light. Metal–insulator–metal plasmonic waveguiding and metallic nanowire scattering are revealed to be responsible for the chromatic shift. Based upon the unique transmission spectrum characteristics of such films, polarized chromatic plasmonic tags (PCPTs) can be flexibly fabricated by patterning dielectric grating templates with designed figures and depositing appropriate thickness of metal. These PCPTs, simultaneously possessing directly visible unpolarized transmission colors and concealed distinct polarization‐dependent color shift, can be widely used as anti‐counterfeiting tags with higher security than the diffractive types of holograms

An investigation of the health value and self-care capabilities of the elderly in urban-rural fringe area nursing homes and the related influencing factors

AbstractObjectiveTo investigate the health value and self-care capabilities of the elderly living in urban-rural fringe area nursing homes and the factors that influence these variables.MethodsA cluster sampling method was used to select 280 elderly individuals from seven urban-rural fringe communities in Xianning to complete a survey regarding their health value and self-care capabilities.ResultsThe total health value and self-care capability scores of the elderly were 7.45 ± 1.45 and 100.25 ± 22.56, respectively. Both of these scores significantly differed by age, education level, marital status, and income (P < 0.05, P < 0.01). Self-care capability was correlated with health value (r = 0.521). A multivariate linear regression analysis showed that health value, marital status, and age predicted self-care capability.ConclusionsElderly people living in the urban-rural fringe area with higher health values also had higher self-care capabilities. The self-care capabilities of the elderly can be enhanced by improving their health value using the “knowing-trusting-acting” model

Genomic Inference of the Metabolism and Evolution of the Archaeal Phylum Aigarchaeota

Microbes of the phylum Aigarchaeota are widely distributed in geothermal environments, but their physiological and ecological roles are poorly understood. Here we analyze six Aigarchaeota metagenomic bins from two circumneutral hot springs in Tengchong, China, to reveal that they are either strict or facultative anaerobes, and most are chemolithotrophs that can perform sulfide oxidation. Applying comparative genomics to the Thaumarchaeota and Aigarchaeota, we find that they both originated from thermal habitats, sharing 1154 genes with their common ancestor. Horizontal gene transfer played a crucial role in shaping genetic diversity of Aigarchaeota and led to functional partitioning and ecological divergence among sympatric microbes, as several key functional innovations were endowed by Bacteria, including dissimilatory sulfite reduction and possibly carbon monoxide oxidation. Our study expands our knowledge of the possible ecological roles of the Aigarchaeota and clarifies their evolutionary relationship to their sister lineage Thaumarchaeota

Propionate Ameliorates Dextran Sodium Sulfate-Induced Colitis by Improving Intestinal Barrier Function and Reducing Inflammation and Oxidative Stress

Propionate is a short chain fatty acid and abundant as butyrate in the gut and blood. However, propionate has been studied less extensively than butyrate in the treatment of colitis. The present study was to investigate the effects of sodium propionate on intestinal barrier function, inflammation and oxidative stress in dextran sulfate sodium (DSS)-induced mice. Animals in DSS group received drinking water from 1 to 6 days and DSS (3% (w/v) dissolved in double distilled water) instead of drinking water from 7 to 14 days. Animals in DSS+Prop group were given 1% sodium propionate for 14 consecutive days and supplemented with 3% DSS solution on day 7-14. Intestinal barrier function, proinflammatory factors, oxidative stress, and signal transducer and activator of transcription 3 (STAT3) signaling pathway in the colon were determined. It was found that sodium propionate ameliorated body weight loss, colon-length shortening and colonic damage in colitis mice. Sodium propionate significantly inhibited the increase of FITC-dextran in serum and the decrease of zonula occludens-1 (ZO-1), occludin and E-cadherin expression in the colonic tissue. It also inhibited the expression of interleukin (IL)-1β, IL-6 and tumor necrosis factor-α (TNF-α) mRNA and phosphorylation of STAT3 in colitis mice markedly, reduced the myeloperoxidase (MPO) level, and increased the superoxide dismutase (SOD) and catalase (CAT) level in colon and serum compared with DSS group. Sodium propionate inhibited macrophages with CD68 marker infiltration into the colonic mucosa of colitis mice. These results suggest that oral administration of sodium propionate could ameliorate DSS-induced colitis mainly by improving intestinal barrier function and reducing inflammation and oxidative stress via the STAT3 signaling pathway