Strain‐rate‐dependent mechanical properties of polypropylene separator for lithium‐ion batteries

The mechanical integrity of battery separators is critical for battery safety and durability. A comprehensive study of strain‐rate‐dependent tensile and puncture properties of a polypropylene lithium‐ion battery separator is presented here with a new model. Due to anisotropy of the polymeric membrane, tensile testing was conducted for different directions. Results showed that tensile strength and elastic modulus were increased 1000% and 500%, respectively, for different directions. It was also demonstrated that tensile strength changed 10 to 25% with strain rate (1.67 × 10^?4 to 1.67 × 10^?1 s^?1) for different directions. An equation was obtained for the first time for flow stress versus strain rate at varied tensile directions with respect to machine direction. Moreover, puncture testing was performed and it was shown that puncture strength was increased 140% with increasing strain rate from 0.25 to 250 mm min^?1. Two failure modes were also observed in puncture samples. Finally, Eyring's model was used to calculate activation enthalpy of the porous polypropylene separator. © 2020 Society of Chemical Industry     

Isolation of antimicrobial agent from the marine algae Cystoseira hakodatensis

Cystoseira hakodatensis is an unutilised brown algae belonging to family Sargassaceae. A crude methanol extract from the algae showed inhibitory effects on the growths of Bacillus cereus and Bacillus licheniformis. To isolate the major antimicrobial agent, a sequential active‐guided isolation procedure was applied: liquid–liquid extraction, column chromatography and bio‐autography. A marked antimicrobial agent (active α) was isolated in hydrophobic fraction and was determined to phenolics without carbohydrates and proteins by phytochemical test. Regarding the antimicrobial potential, the isolated active α showed better inhibitory effects against B. cereus and B. licheniformis at 2 and 4 times of lower concentrations (62.5 and 31.3 μg mL^?1) in comparison with epigallocatechin gallate. These results showed that C. hakodatensis is a potential source of antimicrobial agent capable of preventing the growth of the two bacteria.     

Remote Steering of Self‐Propelling Microcircuits by Modulated Electric Field

The principles and design of “active” self‐propelling particles that can convert energy, move directionally on their own, and perform a certain function is an emerging multidisciplinary research field, with high potential for future technologies. A simple and effective technique is presented for on‐demand steering of self‐propelling microdiodes that move electroosmotically on water surface, while supplied with energy by an external alternating (AC) field. It is demonstrated how one can control remotely the direction of diode locomotion by electronically modifying the applied AC signal. The swimming diodes change their direction of motion when a wave asymmetry (equivalent to a DC offset) is introduced into the signal. The data analysis shows that the ability to control and reverse the direction of motion is a result of the electrostatic torque between the asymmetrically polarized diodes and the ionic charges redistributed in the vessel. This novel principle of electrical signal‐coded steering of active functional devices, such as diodes and microcircuits, can find applications in motile sensors, MEMs, and microrobotics.     

Power Input Prediction in Agitated Gas‐Liquid Contactors with Non‐coalescent Batch

Volumetric mass transfer coefficients, k_La, just as power input are considered as essential parameters for mechanically agitated gas‐liquid contactors in relation to their optimization and design. The knowledge of power input is crucial for the prediction of other mass transfer characteristics. A power input correlation is created for the industrial design of the process with a non‐coalescent batch that would be appropriate for a broad range of operational conditions. The recommended resulting correlation is able to predict the power input for impellers in industrial‐scale design for a significant scope of operational conditions.     

OWL‐based acquisition and editing of computer‐interpretable guidelines with the CompGuide editor

Computer‐Interpretable Guidelines (CIGs) are the dominant medium for the delivery of clinical decision support, given the evidence‐based nature of their source material. Therefore, these machine‐readable versions have the ability to improve practitioner performance and conformance to standards, with availability at the point and time of care. The formalisation of Clinical Practice Guideline knowledge in a machine‐readable format is a crucial task to make it suitable for the integration in Clinical Decision Support Systems. However, the current tools for this purpose reveal shortcomings with respect to their ease of use and the support offered during CIG acquisition and editing. In this work, we characterise the current landscape of CIG acquisition tools based on the properties of guideline visualisation, organisation, simplicity, automation, manipulation of knowledge elements, and guideline storage and dissemination. Additionally, we describe the CompGuide Editor, a tool for the acquisition of CIGs in the CompGuide model for Clinical Practice Guidelines that also allows the editing of previously encoded guidelines. The Editor guides the users throughout the process of guideline encoding and does not require proficiency in any programming language. The features of the CIG encoding process are revealed through a comparison with already established tools for CIG acquisition.     

Rare-earth free sensitizer in NaLuCrF4:Er upconversion material

Upconversion phosphors are known as a material system that can convert near-infrared light into visible/ultraviolet emissions by sequentially absorbing multiple photons. The studies on upconversion materials often use two rare earth (RE) ions as a sensitizer-activator pair. We investigated the influences on luminescence intensity depending on Cr-doping content (x) of hexagonal NaLu_0.98–xCr_xF₄Er_0.02 (x = 0–0.9) upconversion material by substituting Lu³⁺ ions with Cr³⁺in the absence of Gd³⁺. The change in upconversion luminescence intensity appears with saddle-like shape. We suggest that Cr³⁺ ions play the dual role as a constituent in host lattice and a sensitizer in the upconversion process. Optimal conditions for gaining the strongest upconversion emission correspond to x = 0.3–0.5, where there are effective energy transfers between Cr³⁺ and Er³⁺ ions and CrEr dimers. Apart from these values, the emission intensity decreases rapidly which can be ascribed to the absence of multiple-photon absorption for the case of low Cr³⁺ contents, and to the coupling between Cr³⁺ and/or Er³⁺ ions for the case of high Cr³⁺ contents. Magnetization and electron-spin-resonant measurements were performed to understand the correlation between the optical and magnetic properties.     

Effect of sintering temperature on solidification and migration of non-volatile and volatile heavy metals in glass-ceramic

Using tailings as material to prepare glass-ceramic is an excellent way to achieve the resource utilization of solid waste. However, at present, researches on the solidification and migration of heavy metals are limited. Therefore, in this study, ten groups of samples were prepared by controlling sintering temperatures. The solidification, migration, and leaching behavior of non-volatile and volatile heavy metals were studied. The research showed that, with the increase of temperature, the properties of the samples were improved. Fe participated in the phase transformation and evolved into insoluble iron pyroxenes solid solution, while Pb was homogeneously distributed in the glass matrix of glass-ceramics. The leaching concentrations of Fe and Pb in the glass-ceramics were 0.055 mg/L ～0.087 mg/L and 0.074 mg/L ～0.140 mg/L, which were far below the threshold value. The results showed that heavy metals can be effectively solidified in glass-ceramics and have good environmental benefits.     

Energy storage performance of 0.55Bi0.5Na0.5TiO3-0.45SrTiO3 ceramics doped with lanthanide elements (Ln = La,Nd, Dy,Sm) using a viscous polymer processing route

Lead-free bismuth sodium titanate-strontium titanate (NBT-ST) dielectric ceramic materials have been extensively investigated energy storage materials because of their relaxor characteristics. In this study, four different lanthanide elements were introduced into the ferroelectric NBT-ST ceramic to improve their relaxor properties. The introduction of the lanthanide resulted in an increase in disorder at location A within the perovskite lattice and improved relaxor characteristics, leading to a stored energy density of more than 3.5 J/cm³. In particular, an ultrahigh recoverable stored energy density of 4.94 J/cm³ and efficiency of 88.45% were achieved at 440 kV/cm when the NBT-ST ceramic was modified with neodymium. The modified ceramic also exhibited good thermal stability in the range of 30–120 °C, as well as a fast discharge time of ～153 ns, indicating that Nd-incorporated NBT-ST is a promising candidate for electrical energy storage ceramic.