A new design of the elimination and choice translating reality method for multi-criteria group decision-making in an intuitionistic fuzzy environment

The purpose of this paper is to design a new extension of the ELECTRE, known as the elimination and choice translating reality method, for multi-criteria group decision-making problems based on intuitionistic fuzzy sets. This method is widely utilized when a set of alternatives should be identified and evaluated with respect to a set of conflicting criteria by reflecting decision makers’ (DMs’) preferences. However, handling the exact data and numerical measure is difficult to be precisely focused because the DMs’ judgments are often vague in real-life decision problems and applications. A more realistic and practical approach can be to use linguistic variables expressed in intuitionistic fuzzy numbers instead of numerical data to model DMs’ judgments and to describe the inputs in the ELECTRE method. The proposed intuitionsitic fuzzy ELECTRE utilizes the truth-membership function and non-truth-membership function to indicate the degrees of satisfiability and non-satisfiability of each alternative with respect to each criterion and the relative importance of each criterion, respectively. Then, a new discordance intuitionistic index is introduced, which is extended from the concept of the fuzzy distance measure. Outranking relations are defined by pairwise comparisons and a decision graph is depicted to determine which alternative is preferable, incomparable or indifferent in the intuitionistic fuzzy environment. Finally, a comprehensive sensitivity analysis is employed to further study regarding the impact of threshold values on the final evaluation, and a comparative analysis is demonstrated with an application example in flexible manufacturing systems between the proposed ELECTRE method and the existing intuitionistic fuzzy technique for order preference by similarity to ideal solution (IF-TOPSIS) method.     

Fabrication of 3D ordered needle-like polyaniline@hollow carbon nanofibers composites for flexible supercapacitors

Carbon nanofiber-based supercapacitors have broad prospects in powering wearable electronics owing to their high specific capacity,fast charge/discharge process,along with long-cycling life.Herein,a poly(ac rylo n it rile-co-β-methyl hydrogen itaconate) copolymer was prepared and used to synthesize flexible hollow carbon nanofibers(HCNFs) via an electrospinning method without breaking after multiple bending.Subsequently,the inner and outer surfaces of HCNFs were evenly covered with ordered needlelike polyaniline(PANI) through in-situ polymerization methods to obtain three-dimensional flexible HCNFs/PANI composites,which exhibited a high capacity 1196.7 F/g at 1 A/g and good cycling stability(90.1% retention at 5 A/g after 3000 cycles).The symmetrical supercapacitor based on the HCNFs/PANI composites also delive red an outsta nding electrochemical performance with high energy/power density(60.28 Wh/kg at 1000 W/kg) and superior cycling durability(90% capacitance retention after at 5 A/g3000 cycles),which confirmed that the HCNFs/PANI composites had a wide application potential in flexible energy storage devices.     

Arm‐first synthesis of star polymers with polywedge arms using ring‐opening metathesis polymerization and bifunctional crosslinkers

This work presents a two‐step, one‐pot process to make star polymers with polywedge arms. In a one‐pot reaction, after the polywedge arms are synthesized, crosslinker species are added to the reaction, rapidly forming star polymers. Crosslinker species with different degrees of conformational freedom were designed and synthesized and their capacity to generate star polymers was evaluated. Mass conversions up to 92% and stars with up to 17 arms were synthesized with the most rigid crosslinker. The effects of arm molecular weight and molar ratio of crosslinker to arm on mass conversion and arms per star were explored further. Finally, the size‐molecular weight scaling relationship for polywedges with linear and star architectures was compared, corroborating theoretical results regarding star polymers with arms much larger than their core. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 732–740     

Brush‐First ROMP of poly(ethylene oxide) macromonomers of varied length: impact of polymer architecture on thermal behavior and Li+ conductivity

The properties of polymeric materials are dictated not only by their composition but also by their molecular architecture. Here, by employing brush‐first ring‐opening metathesis polymerization (ROMP), norbornene‐terminated poly(ethylene oxide) (PEO) macromonomers ( MM‐n , linear architecture), bottlebrush polymers ( Brush‐n , comb architecture), and brush‐arm star polymers ( BASP‐n , star architecture), where n indicates the average degree of polymerization (DP) of PEO, are synthesized. The impact of architecture on the thermal properties and Li⁺ conductivities for this series of PEO architectures is investigated. Notably, in polymers bearing PEO with the highest degree of polymerization, irrespective of differences in architecture and molecular weight (~100‐fold differences), electrolytes with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) as an Li⁺ source exhibit normalized ionic conductivities (σ_n) within only 4.9 times difference (σ_n = 29.8 × 10^?5 S cm^?1 for MM‐45 and σ_n = 6.07 × 10^?5 S cm^?1 for BASP‐45 ) at a concentration of Li⁺ r = [Li⁺]/[EO] = 1/12 at 50 °C. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 448–455     

Surface modulated hierarchical graphene film via sulfur and phosphorus dual-doping for high performance flexible supercapacitors

The steam-assistant heteroatoms of sulfur and phosphorus dual-doped graphene film fabricated via an ice-template and thermal-activation approach demonstrates an excellent pseudocapacitive behavior in flexible electrochemical capacitors.     

Numerical analysis of stress distribution in the upper arm tissues under an inflatable cuff: Implications for noninvasive blood pressure measurement

An inflatable cuff wrapped around the upper arm is widely used in noninvasive blood pressure measurement. However, the mechanical interaction between cuff and arm tissues, a factor that potentially affects the accuracy of noninvasive blood pressure measurement, remains rarely addressed. In the present study, finite element (FE) mod-els were constructed to quantify intra-arm stresses generated by cuff compression, aiming to provide some theoretical evi-dence for identifying factors of importance for blood pressure measurement or explaining clinical observations. Obtained results showed that the simulated tissue stresses were highly sensitive to the distribution of cuff pressure on the arm sur-face and the contact condition between muscle and bone. In contrast, the magnitude of cuff pressure and small variations in elastic properties of arm soft tissues had little influence on the efficiency of pressure transmission in arm tissues. In par-ticular, it was found that a thickened subcutaneous fat layer in obese subjects significantly reduced the effective pres-sure transmitted to the brachial artery, which may explain why blood pressure overestimation occurs more frequently in obese subjects in noninvasive blood pressure measurement.     

LIQUID CRYSTALLINE POLYMERS. IV. THERMOTROPIC LIQUID CRYSTALLINE POLY(ARYLIDENE-ETHER)S AND COPOLYMERS CONTAINING N-METHYLPIPERIDONE LINKED TO THE MAIN CHAIN THROUGH SPACERS OF VARIOUS LENGTHS

Two novel series of poly(arylidene-ether)s and copoly(arylidene-ether)s were synthesized from N-methylpiperidone and/or cyclohexanone respectively. The first series (homopolymers) was derived from 4,4′-diformyl-α,ω-diphenoxyalkane or 4,4′-diformyl-2,2′ dimethoxy-α,ω-diphenoxyalkane with N-methylpiperidone. The second series (copolymers) was derived from the diphenoxyalkanes (I–VIII) with N-methylpiperidone and cyclohexanone. The inherent viscosities of the polymers thus prepared were in the range of 0.37–0.98 dI/g. The majority of the polymers and copolymers are soluble in chlorinated hydrocarbons. DSC measurements and microscope observation under polarized light demonstrate that this type of poly(arylidene-ether)s form nematic mesophase over a wide temperature range in contrast to the corresponding copoly(arylidene-ether)s. All of the polymers and copolymers exhibited thermotropic liquid crystalline properties. In most cases, the mesophase extends up to 315°C, where thermal decomposition prevents further observation. The morphology of polymer IXb and copolymer XIb as a selected example was examined by scanning electronic microscope.