bluuebunny/crossref_metadata_2025 huggingface dataset:
Recycling and reinforcement potential for the fly ash and sisal fiber reinforced hybrid polypropylene composite
Authors: Maurya Atul Kumar , Gogoi Rupam , Manik Gaurav
Published: December 2021

The investigation explores mechanical, thermal and thermomechanical behavior of hybrid composites post‐recycling, and subsequent, 5 wt.% additional reinforcement to the recyclate of sisal (SSL) fiber fly ash (FA)/polypropylene (PP) hybrid composite. Impact of recycling and 5 wt.% of SSL fiber reinforcement of the recyclate on mechanical properties of hybrid composites made of 15–30 wt.% SSL and 5–15 wt.% FA were investigated. Noticeably, after recycling, a minimal loss of 2.39% only in tensile and 2.20% in flexural strength were recorded for the hybrid composites fabricated with 15 wt.% each of FA and SSL. The highest loss in tensile (10.32%) and flexural (4.22%) strength were reported for only 30 wt.% SSL fiber reinforced PP indicating that hybridization with FA has a benign effect on reducing property degradation. These lost properties were regained by reinforcing recycled composites with 5 wt.% of SSL fiber. Mechanical studies showed that the composite with 30 wt.% SSL fibers recycled and reinforced with additional 5 wt.% fibers showed a substantial improvement of ~10% and ~4% in the tensile and flexural strength while keeping the impact strength stable. FE‐SEM images confirmed a reduction (~67%) in aspect ratio of the SSL fiber due to reprocessing. DMA demonstrated a decrease of ~11% in storage modulus of the composites after first recycling. TGA confirmed an insignificant change in the degradation temperature of the recycled and re‐reinforced recycled composites versus fresh composites. The study paves the way for potential future recycling applications of waste natural fiber reinforced PP.
Hyper‐viscoelastic characterization of highly filled rubber compound: Extending approach for geometrical defect analysis
Authors: Kumar Abhay , Khanra Sipra , Bansal Vidit , Goyal Sharad , Nair Sujith , Hossain Shaikh Jahangir , Chattopadhyay Santanu
Published: December 2021

The work provides insight into the hyper‐viscoelastic characterization of highly filled rubber compound with low structured carbon black, further examining geometrical defects using finite element (FE) simulations. The complete force‐extension behavior and stress relaxation (various strain levels [10%–100%]) in a uniaxial state of stress are reported. The extension at break is reduced by more than 42% for geometrically defective specimens. The breakage of filler–filler interaction attains equilibrium at 75% strain in stress relaxation experiment. Beyond this, the relaxation depends majorly on polymer chains. Hyperelastic material models, namely Ogden, Yeoh, and Arruda–Boyce, are chosen for the present investigation. A Prony series is used for capturing the viscoelastic properties of relaxation times. The combined utilization of the Ogden law and the Prony series in FE simulations provides an excellent match in capturing the experimental features. The effect of geometrical defects is illustrated via solving a series of numerical as well as experimental results. The simulated shape/profile changes such as necking and elliptical formation are excellently comparable with experimental results. Strain localization study shows the stress concentration zone and early prediction of failure location. The methodology presented is potentially crucial for understanding and simulating engineering rubber product's complex structures in general.
Recent advancements in synthesis, properties, and applications of conductive polymers for electrochemical energy storage devices: A review
Authors: Sumdani Md Gulam , Islam Muhammad Remanul , Yahaya Ahmad Naim A. , Safie Sairul Izwan
Published: December 2021

Conductive polymer (CP) research has exploded in popularity over the years, with applications ranging from nanoelectronics to material science. CPs are, for all sorts of purposes, Nobel Prize‐winning compounds, as their inventors received the Nobel Prize in Chemistry in 2000. Conducting polymers have sparked a lot of interest in academic and industrial sectors because they combine the electrical characteristics of semiconductors and metals with the typical benefits of ordinary polymers, such as ease of preparation and low cost production. Conducting polymers have also received a lot of attention because of their unique characteristics, which include customizable electrical properties, excellent optical and mechanical capabilities, ease of synthesis and manufacturing, and superior environmental durability to traditional inorganic materials. In this study, the molecular structures and behaviors of the most common forms of CPs, namely, polyacetylene, polyaniline, polypyrrole, and polythiophene and derivatives of polythiophene are discussed. The transport phenomenon that allow to understand the conduction process, are also described in this review. An in‐depth investigation of conducting polymer‐based binary, ternary, and quaternary composites with carbon‐based materials, metal oxides, transition metals, and inorganic particles is utilized to analyze their applications as supercapacitors and batteries. There are also explanations of recent advancements in their applications in the areas of energy storage systems including batteries and supercapacitors. The development of their applications in the energy storage devices such as supercapacitors, lithium, and other ‐ions batteries, as well as their current issues and future prospect to advance energy storage systems are broadly discussed. This review is intended to contribute to a better understanding of this conducting polymer and, as a result, to the development of new research areas.
Simulative study of polymeric core–shell foam particles for the enlargement of the material portfolio in 3‐D high‐frequency welding
Authors: Schneider Kevin , Ott Constantin , Drummer Dietmar
Published: December 2021

The steam chest molding process is currently state of the art concerning the generation of three‐dimensional polymeric foam components made from particle foams. An adaption of the high‐frequency welding process shows advantages regarding the required energy and the used water. Due to the low dielectric loss factors of the most common foam materials (PE, PP, and PS), they cannot be heated sufficiently by an electric field. To enable heating of these foams, the particles may be coated with a second material that shows a high dielectric loss. The possible heat development of the modified particles was simulatively investigated. To ensure a realistic simulation, the properties of the used materials are analyzed beforehand. The heating simulation shows clear dependence regarding the particle size and the shell thickness. By a suitable combination, sufficient heating is achievable. For single particles, an irregular temperature distribution is calculated, mainly caused by the difference of permittivity resulting in a local variation of electrical flux density. Bigger particles and thicker shells will result in faster heating ramps and higher overall temperatures. The additional calculation regarding a particle–particle interaction shows a homogenization of the temperature distribution across the particle surface.
Additive manufacturing of high‐performance engineering polymers: present and future
Authors: Weyhrich Cody W , Long Timothy E
Published: December 2021

High‐performance engineering polymers continually challenge existing boundaries of rapidly emerging research areas including electronics, transportation, energy, defense and aerospace. Significant research attention over the past decade highlights the exceptional performance of these polymers due to their superior thermomechanical properties and stability under extreme conditions. Unfortunately, inherent structure–property relationships of high‐performance engineering polymers, which predict this unique complement of physical properties, also describe high‐viscosity melts and high melting temperatures. These processing challenges have steered researchers towards advanced processing methods, such as additive manufacturing, that allow for unprecedented control over part geometry. In addition, additive manufacturing serves to advance application–cost relationships, as part optimization and 3D printing of previous monolithic components allow for less material consumption. Currently, the additive manufacturing materials toolbox only contains a fraction of commercially available high‐performance polymers due to unique processing constraints. This review discusses recent efforts towards the successful additive manufacturing of three high‐performance polymer families, i.e. polysulfones, poly(ether ether ketone)s and polyimides. © 2021 Society of Industrial Chemistry.
Processing and rheological behavior of cross‐linked polyethylene containing disulfide bonds
Authors: Montoya‐Ospina Maria Camila , Verhoogt Henk , Osswald Tim A.
Published: December 2021

Vitrimers are a new class of materials that consist of chemically cross‐linked networks that engage in thermoactivated associative exchange reactions. These exchange reactions can impart malleability, healing, and recyclability properties to thermosets. In this study, a one‐step protocol to prepare linear low‐density polyethylene (LLDPE) vitrimer‐like materials with disulfide exchange bonds via reactive blending is presented. The cross‐linking reaction of maleic anhydride‐grafted‐linear low‐density polyethylene (LLDPE‐MAH) and 4,4′‐dithiodianiline was followed in a torque rheometer. The degree of MAH‐functionalization and its impact on the melt rheology, dynamic mechanical properties, and thermal properties of the vitrimer was studied. The cross‐linked LLDPE possessed a mostly elastic behavior, with storage modulus () higher than loss modulus () in the entire frequency range. The complex viscosity of cross‐linked LLDPE at high frequencies (>100 rad/s) was comparable to the thermoplastic LLDPE. The MAH‐groups and formation of cross‐links decreased the degree of crystallinity, which led to a decrease in the storage modulus at a temperature of 35°C. The storage modulus and dimensional stability of the materials improved with cross‐linking density, suggesting potential benefits of LLDPE vitrimers in secondary manufacturing processes. Finally, the reprocessing ability was demonstrated via internal mixing and the rheological and mechanical properties were retained.
Brazilian green propolis: A novel tool to improve the cytotoxic and immunomodulatory action of docetaxel on MCF‐7 breast cancer cells and on women monocyte
Authors: de Oliveira Cardoso Eliza , Santiago Karina Basso , Conti Bruno José , Conte Fernanda Lopes , Tasca Karen Ingrid , Romagnoli Graziela Gorete , de Assis Golim Marjorie , Rainho Cláudia Aparecida , Bastos Jairo Kenupp , Sforcin José Maurício
Published: December 2021

Docetaxel (DTX) is used against breast cancer despite its side effects such as toxicity and immunosuppression. Here we investigated the cytotoxic and immunomodulatory effects of the ethanol solution extract of propolis (EEP) in combination with DTX on MCF‐7 breast cancer cells and on women's monocyte. The cytotoxic potential of EEP + DTX was assessed by MTT assay and the type of tumor cell death was evaluated by flow cytometry. The effects of EEP + DTX on the migration and invasion of MCF‐7 cells were analyzed. Cytokine production by monocytes was assessed by ELISA and the expression of cell surface markers was evaluated by flow cytometry. We also assessed the fungicidal activity of monocytes against Candida albicans and the generation of reactive oxygen species (ROS). Finally, the impact of the supernatants of treated monocytes in the viability, migration, and invasiveness of tumor cells was assessed. EEP enhanced the cytotoxicity of DTX alone against MCF‐7 cells by inducing necrosis and inhibiting their migratory ability. EEP + DTX exerted no cytotoxic effects on monocytes and stimulated HLA‐DR expression, TNF‐α, and IL‐6 production, exerted an immunorestorative action in the fungicidal activity, and reduced the oxidative stress. Our findings have practical implications and reveal new insights for complementary medicine.
Two projector triple products in quantum crystallography
Authors: Matta Chérif F. , Massa Lou
Published: December 2021

Consider a projector matrixP, representing the first order reduced density matrixin a basis of orthonormal atom‐centric basis functions. A mathematical question arises, and that is, how to breakPinto its natural component kernel projector matrices, while preservingN‐representability of. The answer relies upon 2‐projector triple products,P′jPP′j. The triple product solutions, applicable within the quantum crystallography of large molecules, are determined by a new form of the Clinton equations, which—in their original form—have long been used to ensureN‐representability of density matrices consistent with X‐ray diffraction scattering factors. As such, the goal of this paper is to outline a possible pathway for the application of quantum crystallography to crystals of large molecular systems.
Separation and Recovery Process of Copper (II) and Nickel (II) from Wastewater Using Ion Exchange Fiber
Authors: Yang Xibo , Ma Nannan , Jia Yiming , Huang Jiajia , Zhang Xiang
Published: December 2021

In this paper, the parameters affecting the adsorption of CuII and NiII by PAN‐NHx fiber and PAN‐COONa fiber were discussed firstly, such as initial ion concentration, pH, and temperature. Secondly, influence factors toward the separation of CuII and NiII by PAN‐NHx fiber were systematically evaluated by single‐column experiments. The results showed that the PAN‐NHx fiber had good separation of CuII and NiII; NiII accounts for more than 99.00 % of total metal ion content in the initial 1000 mL effluent, while CuII is less than 1 %. With the changed from CCuII: CNiII=90 %:10 % to 95 %:5 %, the ratio of CCuII: CNiII in the treated effluent changed from 6 %: 94 % to 2 %: 98 % (fed flow rate: 0.42 BV min−1). The adsorption capacity of PAN‐NHx adsorption column was well maintained after six cycles. Finally, based on the above laboratory results, a multi‐column process was designed to separate and recover CuII and NiII from wastewater.
Synthesis of Novel 1,3‐Cyclohexadiene Derivatives Bearing 2‐Oxo‐Quinoline Moiety via a 4‐CR Strategy**
Authors: Rezvanian Atieh , Kuhzadeh Parisa , Roosta Atefeh
Published: December 2021

Herein, we report the first example of green synthesis of hybridized 1,3‐cyclohexadiene (1,3‐CHD) scaffolds in moderate to excellent yields. The catalyst‐free sequential four‐component reaction of 2‐chloroquinoline‐3‐carbaldehydes, 1‐phenyl‐2‐(1,1,1‐triphenyl‐λ5‐phosphanylidene)ethan‐1‐one, ethyl acetoacetate and primary amine in ethanol afforded tetrasubstituted 1,3‐cyclohexadienes bearing 2‐oxo‐1,2‐dihydroquinoline moiety during 4 hours. The structure of the synthesized products was determined via X‐ray analysis. This approach is characterized by its operational simplicity, readily available precursors, green solvent, mild conditions, and moderate to excellent yields.
Syntheses and Chiroptical Properties of Optically Active V‐Shaped Molecules Based on Planar Chiral [2.2]Paracyclophane
Authors: Miki Nanami , Maeda Hazuki , Inoue Ryo , Morisaki Yasuhiro
Published: December 2021

Two optically active molecules were prepared using enantiopure planar chiral [2.2]paracyclophane as chiral building blocks, in which π‐electron systems were stacked at 120° to form a V‐shaped structure. The optical and chiroptical properties of the synthesized molecules were investigated experimentally and theoretically. The chiroptical properties depended strongly on the orientation of the stacked π‐electron systems; in other words, these properties could be regulated by changing the orientation of the stacked π‐electron systems.
Highly Ordered Micropores Activated Carbon from Long Fiber Biomass for High Energy Density Supercapacitors
Authors: Zhang Xiao , Li Zhe , Tian Xun , Ma Yanqing , Ma Lei
Published: December 2021

The electrochemical performance of carbon based supercapacitors not only depends on the specific surface area and conductivity, but also the structure of materials. In order to construct the carbon materials with effective structure, the long fibrous plant‐saussurea involucrata stalk was chosen as the new style carbon source. Highly ordered micropores activated carbon (HOMAC) materials have been successfully obtained via KOH chemical activation method. The synthesized HOMAC exhibits high specific surface area of 2692 m2 g−1 and pore volume of 1.14 cm3 g−1. The assembled HOMAC‐based electrode can deliver a high specific capacitance of 379 F g−1 at 2 mV s−1 in 1 M H2SO4 aqueous electrolyte, and show excellent cyclic stability (the capacitance retention ∼95 %) over 10000 cycles at a current density of 1 A g−1, which authenticates excellent charge storage capacity of electrode material. Moreover, the operation voltage window can be expanded to 0–1.8 V in 1 M Na2SO4 electrolyte for the 2‐electrode system. The symmetric supercapacitor can deliver a high energy density of 33.91 Wh kg−1 at power density of 180.03 W kg−1. These high performances can be ascribed to the high surface area and ordered microporous structures obtained using KOH as activator. We further discussed the relationship between fibrous plants and electrochemical performances of the final activated carbon materials. This present work can provide beneficial guidance for the preparation of high performance activated carbon electrodes from a biomass‐based carbon source. Comparing with two different biomass materials, it can be found that the ionic diffusion coefficient of saussurea involucrata is 5.074×10−13 m2 s−1, which is 2.5 times of cotton stalk (1.547×10−13 m2 s−1). This phenomenon indicates the different ion transmission rate in different pore structures.
Material Nanoarchitectonics of Functional Polymers and Inorganic Nanomaterials for Smart Supercapacitors
Authors: Na Jongbeom , Zheng Dehua , Kim Jeonghun , Gao Mengyou , Azhar Alowasheeir , Lin Jianjian , Yamauchi Yusuke
Published: December 2021

Smart supercapacitors are a promising energy storage solution due to their high power density, long cycle life, and low‐maintenance requirements. Functional polymers (FPs) and inorganic nanomaterials are used in smart supercapacitors because of the favorable mechanical properties (flexibility and stretchability) of FPs and the energy storage properties of inorganic materials. The complementary properties of these materials facilitate commercial applications of smart supercapacitors in flexible smart wearables, displays, and self‐generation, as well as energy storage. Here, an overview of strategies for the development of suitable materials for smart supercapacitors is presented, based on recent literature reports. A range of synthetic techniques are discussed and it is concluded that a combination of organic and inorganic hybrid materials is the best option for realizing smart supercapacitors. This perspective facilitates new strategies for the synthesis of hybrid materials, and the development of material technologies for smart energy storage applications.
Ultrarobust Photothermal Materials via Dynamic Crosslinking for Solar Harvesting
Authors: Huang Xin , Liu Jize , Zhou Peng , Su Gehong , Zhou Tao , Zhang Xinxing , Zhang Chuhong
Published: December 2021

Highly efficient and mechanically durable photothermal materials are urgently needed for solar harvesting, but their development still remains challenging. Here, inspired by the hierarchically oriented architecture of natural spider silk, an ultrarobust liquid metals (LMs)/polymer composite is presented via dynamic crosslinking based on the unique mechanical deformable characteristic of LMs. Dynamically cross‐linked core–shell structured LMs droplets can be squeezed along with the orientational crystallization of polymer chains during drawing, thus enabling LMs nanoparticles to be uniformly programmed in the rigid polyethylene nanofiber skeleton. The resultant composite exhibits an unprecedented combination of strong broad‐band light absorption (96.9–99.3%), excellent photothermal conversion ability, remarkable mechanical property (tensile strength of 283.7 MPa, which can lift 200 000 times its own weight), and long‐term structural reliability (bearing 100 000 bending cycles). A powerful and durable solar thermoelectric generator system for real‐environmental solar‐heat‐electricity conversion is further demonstrated, providing a valuable guidance for the design and fabrication of high‐performance solar‐harvesting materials.
Lithium Storage Mechanism and Application of Micron‐Sized Lattice‐Reversible Binary Intermetallic Compounds as High‐Performance Flexible Lithium‐Ion Battery Anodes
Authors: Fang Zhenhan , Duan Shaorong , Liu Haitao , Hong Zixin , Wu Hengcai , Zhao Fei , Li Qunqing , Fan Shoushan , Duan Wenhui , Wang Jiaping
Published: December 2021

A strategy of lattice‐reversible binary intermetallic compounds of metallic elements is proposed for applications in flexible lithium‐ion battery (LIB) anode with high capacity and cycling stability. First, the use of metallic elements can ensure excellent electronic conductivity and high capacity of the active anode substance. Second, binary intermetallic compounds possess a larger initial lattice volume than metallic monomers, so that the problem of volume expansion can be alleviated. Finally, the design of binary intermetallic compounds with lattice reversibility further improves the cycle stability. In this work, the feasibility of this strategy is verified using an indium antimonide (InSb) system. The volumetric expansion and lithium storage mechanism of InSb are investigated by in situ Raman characterization and theoretical calculations. The active material utilization is significantly improved and the growth of In whiskers is inhibited in the micron‐sized ball‐milled and carbon coated InSb (bInSb@C) anode, which exhibits a reversible capacity of 733.8 mAh g−1 at 0.2 C, and provides a capacity of 411.5 mAh g−1 after 200 cycles at 3 C with an average Coulombic efficiency of 99.95%. This strategy is validated in pouch cells, illustrating the great potential of lattice‐reversible binary intermetallic compounds for use as commercial flexible LIB anodes.
Promoted NIR‐II Fluorescence by Heteroatom‐Inserted Rigid‐Planar Cores for Monitoring Cell Therapy of Acute Lung Injury
Authors: Li Yaxi , Zha Menglei , Kang Tianyi , Li Chong , Wu Xue , Wang Shuxian , Lu Song‐Bo , Lee Yi‐Shan , Wu Yun‐Rong , Ni Jen‐Shyang , Li Kai
Published: December 2021

Fluorophores with emission in the second near‐infrared (NIR‐II) window have displayed salient advantages for biomedical applications. However, exploration of new luminogens with high NIR‐II fluorescent brightness is still challenging. Herein, based on the “ring‐fusion” strategy, a series of heteroatom‐inserted rigid‐planar cores is proposed to achieve the bathochromic NIR‐II fluorophores with aggregation‐induced emission (AIE) performance. Interestingly, one of the representative fluorophores, 4,4′‐(5,5′‐([1,2,5]thiadiazolo[3,4‐i]dithieno[2,3‐a:3′,2′‐c]phenazine‐8,12‐diyl)bis(4‐octylthiophene‐5,2‐diyl))bis(N,N‐diphenylaniline) (TTQiT), enjoys a maximum emission beyond 1100 nm because of the efficiently narrowed energy bandgap by electron‐rich sulfur‐atom‐inserted core, which is verified by theoretical calculation. Taking advantage of the bright NIR‐II emission of TTQiT nanoparticles, the desirable in vivo NIR‐II imaging with high signal‐to‐background ratios is successfully performed and a long‐term stem cell tracking in the detection of acute lung injury is further realized. Therefore, it is anticipated that this work will provide a promising molecular engineering strategy to enrich the scope of NIR‐II fluorophores for catering to diverse demands in biomedical applications.
Study on the Structure‐Activity Relationship Between Single‐Atom, Cluster and Nanoparticle Catalysts in a Hierarchical Structure for the Oxygen Reduction Reaction
Authors: Li Yanyan , Zhu Xiaorong , Li Lei , Li Fayan , Zhang Xinyu , Li Yafei , Zheng Zhiping
Published: December 2021

Literature reports have shown that in primary structures, single‐atom catalysts exhibit better performance than cluster and nanoparticles due to their maximum atom utilization and the fine‐tuning of the electronic structure of the active sites. Hierarchical structures have recently been extensively studied because of increased active sites and orderliness of channels significantly improves the catalytic performance compare to primary structures especially in nanoparticles, however, the different sized effect of catalysts research has not been reported. Herein, a unique hollow double‐shell structure (a distinct cavity‐containing) is used as a hierarchical model to study the possible difference between single atom, cluster, and nanoparticle and to establish the corresponding structure‐activity relationship. Three Co catalysts are prepared: single atoms (Co‐Catalyst‐1), clusters (Co‐Catalyst‐2, 0.5–1 nm), and nanoparticles (Co‐Catalyst‐3, ≈5 nm) and their oxygen‐reduction capacity is evaluated. The unique electronic interactions, the strong electron‐withdrawing ability of N in Co–N4 (Co‐Catalyst‐1), attract electrons from the electrode to Co, specifically by expediting the generation and transformation of the rate‐determining step intermediates *OOH. The variant spatial structure which is caused by Co atom aggregation, and led to surface area, pore size, and carbon disorder, is a distinct, therefore significant variation in mass and charge transport efficiency, and activities.
Axial Scanning Metal‐Induced Energy Transfer Microscopy for Extended Range Nanometer‐Sectioning Cell Imaging
Authors: Hwang Wonsang , Kim Dongeun , Kim Dugyoung
Published: December 2021

Nanometer‐sectioning optical microscopy has become an indispensable tool in membrane‐related biomedical studies. Finally, many nanometer‐sectioning imaging schemes, such as variable‐angle total internal reflection fluorescence microscopy, metal‐induced energy transfer (MIET) imaging, and supercritical‐angle fluorescence microscopy have been introduced. However, these methods can measure a single layer of molecules, and the measurement ranges are below 100 nm, which is not large enough to cover the thickness of lamellipodium. This paper proposes an optical imaging scheme that can identify the axial locations of two layers of molecules with an extended measurement range and a nanometer‐scale precision by using MIET, axial focal plane scanning, and biexponential analysis in fluorescence lifetime imaging microscopy. The feasibility of the proposed method is demonstrated by measuring an artificial sample of a known structure and the lamellipodium of a human aortic endothelial cell whose thickness ranges from 100 to 450 nm with 18.3 nm precision.
Imaging the Single‐Electron Ln–Ln Bonding Orbital in a Dimetallofullerene Molecular Magnet
Authors: Paschke Fabian , Birk Tobias , Avdoshenko Stanislav M. , Liu Fupin , Popov Alexey A. , Fonin Mikhail
Published: December 2021

Chemically robust single‐molecule magnets (SMMs) with sufficiently high blocking temperatures TB are among the key building blocks for the realization of molecular spintronic or quantum computing devices. Such device applications require access to the magnetic system of a SMM molecule by means of electronic transport, which primarily depends on the interaction of magnetic orbitals with the electronic states of the metallic electrodes. Scanning tunneling microscopy in combination with ab initio calculations allows to directly address the unoccupied component of the single‐electron molecular orbital that mediates the ferromagnetic exchange coupling between two 4f ions within a lanthanide endohedral dimetallofullerene deposited on a graphene surface. The single‐electron metal–metal bond provides a direct access to the molecule's magnetic system in the transport experiments, paving the way for investigation and controlled manipulation of the spin system of individual dimetallofullerene SMMs, essential for molecular spintronics.
An Active‐Oxygen‐Scavenging Oriented Cathode‐Electrolyte‐Interphase for Long‐Life Lithium‐Rich Cathode Materials
Authors: Wang Yajing , Cai Senrong , Sun Zongqiang , Hou Qing , Huang Haihong , Cheng Jiancong , Fan Jingmin , Zheng Mingsen , Dong Quanfeng
Published: December 2021

Lithium‐rich layered oxides with high energy density are promising cathode materials, thus having attracted a large number of researchers. However, the materials cannot be commercialized for application so far. The crucial problem is the releasing of lattice oxygen at high voltage and resulting consequence, such as decomposition of electrolyte, irreversible phase transition of crystal structure, capacity degradation, and voltage decay. Therefore, capturing active‐oxygen and further constructing a cathode‐electrolyte‐interface (CEI) protective layer via the scavenging effects should be a fundamental step to solve these issues. Herein, β‐carotene with antioxidant properties is used as a scavenging molecule to achieve this goal. The control of active oxygen species effectively alleviates the decomposition of carbonate electrolyte under high voltage. The introduction of β‐carotene additives can also be adjusted in situ to generate a customized CEI film, which is a double‐layer structure with external organic components and internal inorganic components. Moreover, the β‐carotene‐containing electrolyte system exhibits better thermal stability. Benefited from these, Lithium‐rich cathode of β‐carotene‐containing electrolyte shows outstanding long‐life cycle stability, with 93.4% capacity retention rate after 200 cycles at 1 C; this electrochemical stability is superior to other electrolyte additive systems reported at present.
Sulfur Vacancies‐Engineered Ni3S4‐x Hollow Microspheres with Optimized Anionic Adsorption Energy for High‐Performance Supercapacitor
Authors: Zhang Jiawei , Li Yu , Liang Xinqi , Liu Qian , Chen Qingguo , Chen Minghua
Published: December 2021

Nickel sulfides with high theoretical capacitance have aroused tremendous attention for next‐generation supercapacitors. Unfortunately, the structural durability of nickel sulfides is insufficient to support the long‐term working situation. Herein, Ni3S4‐x hollow microspheres with sulfur vacancies (Ni3S4‐x HMs) are constructed by a liquid‐phase anion exchange process using the Ni‐MOF as the precursor. Both experimental investigation and theoretical analysis suggest that the deliberately introduced sulfur vacancies effectively improve the anionic adsorptive ability of nickel sulfides in the KOH electrolyte, significantly enhancing the reversible capacitance and structural durability (1884 F g‐1 at 2 A g‐1, capacity retention of 97.9% after 10 000 cycles). In addition, an asymmetrical solid‐state supercapacitor consisting of Ni3S4‐x HMs cathode and activated carbon anode shows infusive energy/power density (33.05 Wh kg‐1/1.68 kW kg‐1) and remains 82.4% over 10 000 repeated charging/discharging processes in the KOH‐PVA gel electrolyte. The strategies can be developed to enlighten the structural design of various metal sulfides materials adopted in electrochemical energy storage devices including alkali ion batteries, supercapacitors, and electrocatalysts.
Quench‐Induced Surface Engineering Boosts Alkaline Freshwater and Seawater Oxygen Evolution Reaction of Porous NiCo2O4 Nanowires
Authors: Yang Jin , Wang Yanan , Yang Jie , Pang Yajun , Zhu Xinqiang , Lu Yinzhuo , Wu Yitian , Wang Jiajie , Chen Hao , Kou Zongkui , Shen Zhehong , Pan Zhenghui , Wang John
Published: December 2021

The electrochemical oxygen evolution reaction (OER) by efficient catalysts is a crucial step for the conversion of renewable energy into hydrogen fuel, in which surface/near‐surface engineering has been recognized as an effective strategy for enhancing the intrinsic activities of the OER electrocatalysts. Herein, a facile quenching approach is demonstrated that can simultaneously enable the required surface metal doping and vacancy generation in reconfiguring the desired surface of the NiCo2O4 catalyst, giving rise to greatly enhanced OER activities in both alkaline freshwater and seawater electrolytes. As a result, the quenched‐engineered NiCo2O4 nanowire electrode achieves a current density of 10 mA cm−2 at a low overpotential of 258 mV in 1 m KOH electrolyte, showing the remarkable catalytic performance towards OER. More impressively, the same electrode also displays extraordinary activity in an alkaline seawater environment and only needs 293 mV to reach 10 mA cm−2. Density functional theory (DFT) calculations reveal the strong electronic synergies among the metal cations in the quench‐derived catalyst, where the metal doping regulates the electronic structure, thereby yielding near‐optimal adsorption energies for OER intermediates and giving rise to superior activity. This study provides a new quenching method to obtain high‐performance transition metal oxide catalysts for freshwater/seawater electrocatalysis.
Regulating Interfacial Desolvation and Deposition Kinetics Enables Durable Zn Anodes with Ultrahigh Utilization of 80%
Authors: Jin Hongrun , Dai Simin , Xie Kefeng , Luo Yongxin , Liu Kaisi , Zhu Zehao , Huang Liwei , Huang Liang , Zhou Jun
Published: December 2021

Rechargeable aqueous zinc ion batteries (ZIBs) represent a promising technology for large‐scale energy storage due to their high capacity, intrinsic safety and low cost. However, Zn anodes suffer from poor reversibility and cycling stability caused by the side‐reactions and dendrite issues, which limit the Zn utilization in the ZIBs. Herein, to improve the durability of Zn under high utilization, an aluminum‐doped zinc oxide (AZO) interphase is presented. The AZO interphase inhibits side reactions by isolating active Zn from the bulk electrolyte, and enables facile and uniform Zn deposition kinetics by accelerating the desolvation of hydrated Zn2+ and homogenizing the electric field distribution. Accordingly, the AZO‐coated Zn (AZO@Zn) anode exhibits a long lifespan of 600 h with Zn utilization of 34.1% at the current density of 10 mA cm−2. Notably, even under ultrahigh Zn utilization of 80%, the AZO@Zn remains stable cycling over 200 h. Meanwhile, the V2O5/AZO@Zn full cell with limited Zn excess displays high capacity retention of 86.8% over 500 cycles at 2 A g−1. This work provides a simple and efficient strategy to ensure the reversibility and durability of Zn anodes under high utilization conditions, holding a great promise for commercially available ZIBs with competitive energy density.
Binder‐Free and High‐Loading Cathode Realized by Hierarchical Structure for Potassium–Sulfur Batteries
Authors: Yang Kaiwei , Kim Soochan , Yang Xin , Cho Misuk , Lee Youngkwan
Published: December 2021

Potassium–sulfur batteries have attracted significant research attention owing to the naturally abundant resources of potassium and sulfur, and have promising applications in large‐scale energy storage systems. However, the sluggish reaction kinetics of K+, low reaction activity of sulfur species, shuttling effect of polysulfides, and large volume change impede the development of these batteries. Moreover, the conventional electrode fabrication method with binders and current collectors renders it difficult to improve the areal sulfur loading and energy density. In this study, a binder‐free and freestanding sulfur cathode is prepared by phase inversion and sulfurization of polyacrylonitrile. This sulfur cathode, with a hierarchically porous network, enables a high reversible capacity of 1345 mAh g−1 and a stable cycling performance with a capacity decay of 0.15% per cycle. Importantly, areal capacities of 3.1 and 4.2 mAh cm−2 are achieved even at high sulfur loadings of 3 and 7 mg cm−2, owing to the favorable electron/ion transport in the cathode. The facile preparation method and excellent electrochemical properties reported herein can pave the way for developing high‐performance K‐S batteries.
Interfacial Microenvironment Modulation Enhancing Catalytic Kinetics of Binary Metal Sulfides Heterostructures for Advanced Water Splitting Electrocatalysts
Authors: Qian Yongteng , Yu Jianmin , Zhang Ya , Zhang Fangfang , Kang Yingbo , Su Chenliang , Shi Hu , Kang Dae Joon , Pang Huan
Published: December 2021

Interfacial microenvironment modulation has been proven to be a promising route to fabricate highly efficient catalysts. In this work, the lattice defect‐rich NiS2/MoS2 nanoflakes (NMS NFs) electrocatalysts are successfully synthesized by a simple strategy. Benefiting from the abundant lattice defects and modulated interfacial microenvironment between NiS2 and MoS2, the prepared NMS NFs show superior catalytic activity for water splitting. Particularly, the optimized NMS NFs (the molar ratio of Ni:Mo = 5:5) exhibit remarkable catalytic activity toward overall water splitting with a voltage of 1.60 V at 10 mA cm−2 in alkaline media, which is lower than that of the noble‐metal‐based electrocatalysts (1.68 V at 10 mA cm−2). The NMS NFs electrocatalysts also show exceptional long‐term stability (>50 h) for overall water splitting. The density functional theory results demonstrate that the injection of NiS2 into MoS2 can greatly optimize the catalytic kinetics and reduce the energy barrier for hydrogen/oxygen evolution reactions. The work does not only offer a promising candidate for a highly efficient water splitting electrocatalyst but also highlights that interfacial microenvironment modulation is a potential strategy to optimize the catalytic kinetics.
Zero‐Waste Scalable Blade–Spin Coating as Universal Approach for Layer‐by‐Layer Deposition of 3D/2D Perovskite Films in High‐Efficiency Perovskite Solar Modules
Authors: Zendehdel Mahmoud , Yaghoobi Nia Narges , Paci Barbara , Generosi Amanda , Di Carlo Aldo
Published: December 2021

Perovskite solar cells (PSCs) are a type of emerging thin‐film photovoltaics, which show a promising potential to catch a major portion of the near future market. However, hazardous waste‐generation and cost‐management of the industrial production are two key issues which need to be addressed in the commercialization process. Herein, a universal coating strategy is introduced by combination of blade and spin coating to realize a zero‐waste‐generation of the perovskite precursor materials for layer‐by‐layer deposition of 3D/2D perovskite films on large‐area substrates with high uniformity and reproducibility. This leads to eliminate 90% and 95% of the materials consumption compared to the conventional spin‐coating for deposition of the 3D and 2D perovskite layers, respectively, without changing of the ink precursor. Large‐area PSCs have been realized by blade–spin/blade coating approach reaching 19.55% photo‐conversion efficiency (PCE) over 0.92 cm2 masked area and >1000 h T90 thermal stability at 85 °C. Fabricated perovskite solar modules via blade–spin/blade deposition have been reached to 18.8% PCE over 10 cm2 active‐area. The economic analysis shows the potential for >90% decrease of the operational expenditure via break‐down of the material costs from 1.99 € m−2 in spin coating method to 0.18 € m−2 in blade–spin/blade coating approach.
Zur Ermüdungsfestigkeit großer Schrauben im Stahlbau unter Berücksichtigung von Herstell‐ und Randschichteinflüssen – Teil 1: Bisheriger Kenntnisstand
Authors: Glienke Ralf , Schwarz Mathias , Marten Frithjof , Eichstädt Rasmus , Schwerdt Daniela , Meyer Melanie , Dörre Maik
Published: December 2021

Die Ermüdungsfestigkeit von Stahlbauschrauben wird maßgeblich von Herstellungseinflüssen beeinflusst. In den Bemessungsgrundlagen werden diese Einflussfaktoren, abhängig vom jeweils herangezogenen Regelwerk, sehr uneinheitlich berücksichtigt. Insbesondere für Schrauben großer Durchmesser, wie sie z. B. bei Windenergieanlagen in hoher Stückzahl zum Einsatz kommen, war eine experimentelle Grundlage zur Bewertung verschiedener Einflüsse in der Vergangenheit nur sehr begrenzt verfügbar. Im Teil 1 des vorliegenden Beitrags wird der bisherige Kenntnisstand dargelegt, der die maßgebenden Einflussgrößen auf die Ermüdungsfestigkeit von Schrauben im Stahlbau beschreibt. Hieraus werden von den Verfassern die Grundlagen zur Bewertung von bestehenden und (242) bislang unveröffentlichten Ergebnissen aus Schwingfestigkeitsuntersuchungen an axial belasteten Schraube‐Mutter‐Verbindungen bis zur Nenngröße M64 abgeleitet, die im Teil 2 dieses Beitrags enthalten sind. Im Vordergrund stehen dabei der Größen‐ und Randschichteinfluss, der Einfluss der Gewindeherstellung sowie der Beanspruchungszustand aus der ziehenden Anziehpraxis.
Zur Ermüdungsfestigkeit großer Schrauben im Stahlbau unter Berücksichtigung von Herstell‐ und Randschichteinflüssen – Teil 2: Versuchsergebnisse und Bewertung
Authors: Glienke Ralf , Schwarz Mathias , Marten Frithjof , Eichstädt Rasmus , Schwerdt Daniela , Meyer Melanie , Dörre Maik
Published: December 2021

Die Ermüdungsfestigkeit von Stahlbauschrauben wird maßgeblich von Herstellungseinflüssen beeinflusst. In den Bemessungsgrundlagen werden diese Einflussfaktoren, abhängig vom jeweils herangezogenen Regelwerk, sehr uneinheitlich berücksichtigt. Insbesondere für Schrauben großer Durchmesser, wie sie z. B. bei Windenergieanlagen in hoher Stückzahl zum Einsatz kommen, war eine experimentelle Grundlage zur Bewertung verschiedener Einflüsse in der Vergangenheit nur sehr begrenzt verfügbar. In diesem Beitrag werden Ergebnisse von 20 verschiedenen, größtenteils in der jüngeren Vergangenheit durchgeführten Versuchsserien an drei unterschiedlichen hochfesten Schraubensystemen mit variierenden Herstellungsbedingungen vorgestellt und bewertet. Die Datenbasis streckt sich über einen Durchmesserbereich zwischen M12 und M64 und legt den Fokus auf Versuche mit hohem repräsentativem Mittelspannungsniveau. Die Ergebnisse werden unter Einbeziehung der in der Fachliteratur beschriebenen Erkenntnisse in Bezug auf unterschiedliche Herstellungseinflüsse bewertet und den Regelungen der relevanten internationalen normativen Bemessungsgrundlagen gegenübergestellt. Dabei werden zusätzlich zu den Ergebnissen von Schwingfestigkeitsversuchen ergänzende metallografische Untersuchungen zur Bruchflächengestalt sowie zum Rand‐ und Schutzschichtzustand herangezogen. Auf dieser Basis werden abschließend Handlungsempfehlungen abgeleitet und ein Ausblick auf weitere zielführende Untersuchungen gegeben.
Recent Advances in Processing and Applications of Heterobimetallic Oxide Thin Films by Aerosol‐Assisted Chemical Vapor Deposition
Authors: Ehsan Muhammad Ali , Shah Syed Shaheen , Basha Shaik Inayath , Hakeem Abbas Saeed , Aziz Md. Abdul
Published: December 2021

The fabrication of smart, efficient, and innovative devices critically needs highly refined thin‐film nanomaterials; therefore, facile, scalable, and economical methods of thin films production are highly sought‐after for the sustainable growth of the hi‐tech industry. The chemical vapor deposition (CVD) technique is widely implemented at the industrial level due to its versatile features. However, common issues with a precursor, such as reduced volatility and thermal stability, restrict the use of CVD to produce novel and unique materials. A modified CVD approach, named aerosol‐assisted CVD (AACVD), has been the center of attention due to its remarkable tendency to fabricate uniform, homogenous, and distinct nano‐architecture thin films in an uncomplicated and straightforward manner. Above all, AACVD can utilize any custom‐made or commercially available precursors, which can be transformed into a transparent solution in a common organic solvent; thus, a vast array of compounds can be used for the formation of nanomaterial thin films. This review article highlights the importance of AACVD in fabricating heterobimetallic oxide thin films and their potential in making energy production (e. g., photoelectrochemical water splitting), energy storage (e. g., supercapacitors), and environmental protection (e. g., electrochemical sensors) devices. A heterobimetallic oxide system involves two metallic species either in a composite, solid solution, or metal‐doped metal oxides. Moreover, the AACVD tunable parameters, such as temperature, deposition time, and precursor, which drastically affect thin films microstructure and their performance in device applications, are also discussed. Lastly, the key challenges and issues of scaling up AACVD to the industrial level and processing for emerging functional materials are also highlighted.
Influence of tower shadow on downwind flexible rotors: Field tests and simulations
Authors: Simpson Juliet G. , Kaminski Meghan , Loth Eric
Published: December 2021

As wind turbine rotors become larger, the blades become more flexible, requiring extra stiffness and cost to avoid the risk of tower strike. Wind turbines in a downwind configuration have a reduced risk of tower strike because the rotor thrust acts away from the tower. However, downwind blades pass through the wake of the tower, and the resulting load variation may contribute to blade fatigue. To date, there have been no field tests to quantify this tower shadow effect on unsteady blade moments. The present study reports on the first field testing of a flexible, downwind, coned rotor and compares the experimental data against simulations run in OpenFAST. The tower shadow effect is simulated using the conventional Powles model and a new Eames model (developed herein), which includes the influence of upstream turbulence. Both models reasonably predict the blade root out‐of‐plane bending moment data and the tower shadow dip magnitude when compared to field test data in Region 3. Tower shadow was found to increase the short‐term Damage Equivalent Loads (DELs) by less than 10% compared to other effects (gravity, shear, and turbulence), and the predictions were consistent with experiments. These results indicate that the tower shadow effect can be reasonably modeled with the simpler Powles model and that the tower shadow effect can be small compared to the effect of turbulence. However, long‐term fatigue due to tower shadow should be included in detailed structural analysis and design of the rotor and the tower.
Erklärbarkeit der altersadjustierten Übersterblichkeit mit den COVID-19-attribuierten Sterbefällen von Januar 2020 bis Juli 2021
Authors: Wollschläger Daniel , Schmidtmann Irene , Fückel Sebastian , Blettner Maria , Gianicolo Emilio
Published: December 2021

Hintergrund

Unsicherheiten in der Todesursachencodierung erschweren die Bestimmung der durch COVID-19 verursachten Mortalität. Dagegen ist die altersadjustierte Übersterblichkeit ein robuster Indikator für Auswirkungen der COVID-19-Pandemie auf die öffentliche Gesundheit. Die Übersterblichkeit spiegelt neben COVID-19-Sterbefällen aber potenziell auch negative Folgen der Maßnahmen zur Pandemieeindämmung wider.

Ziele

Diese Studie prüft, ob es in Deutschland von 01/2020 bis 07/2021 eine Übersterblichkeit gab, die nicht durch COVID-19 erklärbar ist, sondern für indirekte Effekte gesundheitspolitischer Maßnahmen auf die Mortalität spricht.

Methoden

Übersterblichkeitstrends im Zeitraum von 01/2020 bis 07/2021, jeweils in den Bundesländern sowie in den Kreisen von Rheinland-Pfalz, wurden auf Konsistenz mit COVID-19 zugeschriebenen Sterbefällen geprüft. Die erwarteten monatlichen Sterbefälle wurden auf Basis der Daten von 2015 bis 2019 vorhergesagt. Dabei wurden die Bevölkerungsstruktur, Lufttemperatur, saisonale Influenzaaktivität sowie zyklische und langfristige Zeittrends berücksichtigt.

Ergebnisse

In 232/304 (76,3 %) Monat-Bundesland- bzw. in 607/684 (88,7 %) Monat-Kreis-Kombinationen lag die COVID-19 zugeschriebene Mortalität innerhalb der 95 %-Vorhersageintervalle für die Übersterblichkeit. Die Rangkorrelation zwischen Übersterblichkeit und COVID-19-attribuierter Mortalität betrug für die Bundesländer 0,42 (95 %-Konfidenzintervall [0,31; 0,53]) und für die Kreise 0,21 (95 %-Konfidenzintervall [0,13; 0,29]).

Diskussion

Die gute Übereinstimmung der räumlich-zeitlichen Übersterblichkeitsmuster mit den COVID-19 zugeschriebenen Sterbefällen ist konsistent mit der Annahme, dass die Maßnahmen zur Eindämmung der COVID-19-Pandemie zwischen 01/2020 und 07/2021 nicht wesentlich zur Übersterblichkeit in Deutschland beigetragen haben.