Abstract
In this work, polylactic acid (PLA)/copolymer blends were prepared by melt blending. Ethylene‐glycidyl methacrylate (E‐GMA) and ethylene‐butyl acrylate‐maleic anhydride (EBA‐MAH) functional ...block copolymers were used. A ternary blend of PLA/E‐GMA/EBA‐MAH was also studied. FTIR analyses evidenced the occurrence of reactive compatibilization of E‐GMA and EBA‐MAH with PLA in the binary blends due to the reactivity of the GMA and MAH functional groups with the terminal hydroxyl and carboxyl groups of PLA. Rheological measurements evidenced the occurrence of cross‐link reactions between E‐GMA and EBA‐MAH copolymers in the ternary blend. Three distinct morphologies were observed in the blends: PLA/E‐GMA exhibited a sea‐island structure, PLA/EBA‐MAH exhibited a co‐continuous structure, and PLA/E‐GMA/EBA‐MAH exhibited a semi‐interpenetrating polymer network (SIPN) structure. The shape memory effect (SME) of PLA and PLA/copolymers blends was evaluated by three different methods: fold‐deploy, tension, and torsion. Fold‐deploy tests were conducted in a water bath, whereas the tension and torsion tests were conducted using a rheometer. All methods proved to be effective; however, some precautions must be taken to choose the most suitable test for a given purpose, which is thoroughly discussed in this work. The SME of PLA was enhanced through the incorporation of the copolymers. Blending PLA with E‐GMA, EBA‐MAH, and E‐GMA/EBA‐MAH copolymers increased its shape recovery from 32% to 84%, 79.2%, and 80%, respectively, while its shape fixity remained around 100%.
•Frequency distribution of root cause for passenger vehicle recalls.•Classification schemes for defective components and defect types.•Significant associations between defective components and defect ...types.•Functional Block Diagram of Airbag System.•Failure Mode Effect and Analysis (FMEA) of Airbag.
This study analysed 345 passenger vehicle recalls that were reported to the National Highway Traffic Safety Administration. The root cause analysis was applied to analyse each recall event in order to derive the cause of the recall, i.e., the defect type. Classification schemes were developed to organize the defective components and defect type into useful categories. The defect types were classified into manufacturing defects, design flaws, and mislabelling. Each of the above categories was expanded into smaller subcategories and items. Following the root cause analysis, the functional block diagram, and failure modes and effects analysis (FMEA) were applied to translate defective recall cases into FMEA tabular statements. Cramer's V and Phi coefficient analyses were applied to identify significant associations between defective components and defect types to prevent the future recurrence of recalls and improve vehicle quality. This study demonstrated that root cause and FMEA, based on an orthogonal classification scheme, can be applied to derive feasible solutions for reducing vehicle safety recalls, and such analysis can be generalized to other products or manufacturing processes.
Abstract A 16-year-old man presented with short VA supraventricular tachycardia and 2:1 atrioventricular ratio. The correct maneuvers allowed us to guide not only the mechanism but also the probable ...location of the atrioventricular block.
Abstract
At present, the construction of logistics parks has become an indispensable part of the modern logistics system. Scientific and reasonable layout planning of the logistics parks not only ...effectively saves logistics costs, but also promotes the efficient operation of the entire logistics. This article uses a combination of qualitative analysis and quantitative analysis to analyze the layout structure of the functional areas, build a multi-objective mathematical model with the largest degree of adjacency and the smallest transportation cost, and set the functional blocks in horizontal and vertical modes to make the layout more rational, Using genetic algorithm to solve the model with Matlab software, and verify the rationality and effectiveness of the model through examples, providing a new idea for the layout of modern logistics parks.
In article number 1800846, Hiroshi Yabu, Guillaume Delaittre, and co‐workers propose a simple procedure to prepare nanoparticles with surface‐expressed reactive patches and corresponding nanodiscs by ...a nanoprecipitation technique with functional block copolymers. The surface pattern formation is controlled by the preparation conditions. Spatially confined functionalization is demonstrated by grafting model thiol compounds. These nanomaterials are structurally approaching biological particles and are interesting building blocks for colloidal assemblies.
Nanoparticles with structural or chemical anisotropy are promising materials in domains as diverse as cellular delivery, photonic materials, or interfacial engineering. The surface chemistry may play ...a major role in some of these contexts. Introducing reactivity into such polymeric nanomaterials is thus of great potential, yet is still a concept in its infancy. In the current contribution, a simple nanoprecipitation technique leads to nanoparticles with diameters as low as 150 nm and well‐defined reactive surface patches of less than 30 nm in width, as well as surface‐reactive flat, disc‐like nanoparticles with corresponding dimensions, via an additional crosslinking/delamination sequence. To this aim, chemically doped block copolymers (BCPs) are employed. Control over morphology is attained by tuning preparation conditions, such as polymer concentration, solvent mixture composition, and blending with non‐functional BCP. Surface reactivity is demonstrated using a modular ligation method for the site‐selective immobilization of thiol molecules. The current approach constitutes a straightforward methodology requiring minimal engineering to produce nanoparticles with confined surface reactivity and/or shape anisotropy.
Nanoparticles with surface‐expressed reactive patches and corresponding nanodiscs are prepared by a simple nanoprecipitation technique with functional block copolymers. The surface pattern formation is controlled by preparation conditions (concentration, solvent, and functionality). Spatially confined functionalization is demonstrated by grafting model thiol compounds. These nanomaterials are structurally approaching biological particles and are interesting building blocks for colloidal assemblies.
Recently, multi-infeed line-commutated converter-based high-voltage direct currents (LCC-HVDCs) represent one of the most attractive ways to accommodate large-scale power transfer in main load ...centers. However, this approach deteriorates the dynamic var reserve (DVR) in the receiving-end power grid, especially in scenarios with heavy loads. If the system does not reserve sufficient dynamic var in advance, a severe voltage dip may occur and further lead to consecutive commutation failures, ultimately resulting in DC blocking and voltage collapse. To address the voltage/var control challenges, a robust DVR assessment method is proposed in this paper. This method is used to determine both the inductive and capacitive DVR and prevent cascading failures. First, continuous dynamic algebraic equations are formulated using a piecewise functional block approximation method for efficient application of second-order trajectory sensitivity analysis (SOTSA). Next, a robust DVR assessment model is formulated, and the corresponding computational strategy is introduced to effectively and accurately solve the large-scale problem. Finally, in numerical simulations, the computational efficiency and accuracy of the proposed method are verified using a simple system and operational data from a real system in the Eastern China Power Grid.
Nickel-rich layered materials (LiNi0.8Co0.1Mn0.1O2, NCM811) are subject to electrochemical performance degradation and structural damage at high voltage. A new concept is proposed in this work using ...a multi-functional block copolymer of poly (urethane)-block-poly (dimethyl siloxane) (PUDMS) to modify the NCM811 particle surface and improve the high voltage electrochemical performance. The near NCM811 particle surface solvation structure of the electrolyte is tuned by the PU block to suppress electrolyte solvent decomposition and promote the formation of an electrochemically stable CEI layer. The HF attack is inhibited by the PDMS block resulting in reduced transition metal dissolution and retarded structure degradation. With the PUDMS modification, the capacity retention of the half-cell with the NCM811 cathode is significantly improved (63.6 % vs. 75.9 % after 200 cycles, 1C, 2.8–4.5 V). The cyclic stability of the NCM811||graphite is enhanced with the capacity retention increased from 63.7 % to 80.2 % (0.5C, 2.8–4.5 V).
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•A new multi-functional block copolymer of PU and PDMS is used to modify NCM811.•Near surface lithium-ion solvation structure is manipulated by PUDMS.•HF is scavenged by PUDMS to stabilize NCM811 cathode structure.•Full cell electrochemical performance is improved with PUDMS modification.
A novel POEGMA-b-(PMEEU-co-PMAA) (poly(oligo(ethylene glycol) methacrylate)-b-poly((methacrylamidoethyl) ethylene urea)-co-poly(methacrylic acid) block copolymer has been synthesized by RAFT ...polymerization as a corrosion inhibitor. Structural characterization of the block copolymer was done by FTIR,
13
C NMR and
1
H NMR spectroscopic techniques. The carboxylic acid and cyclic urea units on the block copolymer exert a synergistic effect on corrosion inhibition through chelating of the metal ions or adsorption to the metal surface. Corrosion inhibition of SAE 1012 carbon steel in a 1 M HCl medium has been investigated in the presence of 5 mM polymer using both experimental (electrochemical impedance spectroscopy, Tafel polarization (TP), weight loss) and theoretical approaches. Also, SAE 1012 carbon steel surface morphology changes were followed by energy dispersive X-ray spectroscopy and scanning electron microscopy. Electrochemical techniques indicated that the presence of PMEEU-co-PMAA segments of the polymer in the acid solution inhibits corrosion of SAE 1012 carbon steel. The inhibition efficiency of the polymer was found to be about 85%. According to TP studies, PMEEU-co-PMAA segment acts as a mixed type corrosion inhibitor. The adsorption of PMEEU-co-PMAA molecules onto the metal surface follows Langmuir adsorption isotherm. The K
ads
value calculated from the equilibrium constant of the adsorption process reflects a strong interaction. SEM and EDAX studies provide evidence of PMEEU-co-PMAA adsorption on the metal surface.
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