Characterization of Alginate/Silver Nanobiocomposites Synthesized by Solution Plasma Process and Their Antimicrobial Properties

Solution plasma process (SPP) was adopted to prepare alginate/silver nanoparticle (AL/AgNP) biocomposites. The biocomposites were synthesized in solutions of varying concentrations of AgNO3 (1−5 mM) and alginate (0.1−0.3%, w/w) by discharging plasma for 7 min at 800 V with 30 kHz frequency using a pulsed unipolar power supply. The AL/AgNP emulsion was fabricated into 3D scaffolds by freeze drying and lyophilization and then stabilized by cross-linking via UV irradiation. UV-Vis spectroscopy of the biocomposites showed a characteristic absorbance at the maximum of 415–440 nm with increase in the intensity of the peaks as the concentration of AgNO3 increased. FE-SEM analysis showed that the 3D scaffolds had microporous structures with fine and uniform pores of 3–9 ± 2.0 μm in diameter. TEM analysis revealed that AgNPs in the biocomposites were in spherical shape with size range of 5–40±2.0 nm (AL0.3/Ag5) and well distributed in the matrix. The AL/AgNP biocomposites showed microbicidal activity against 9 human pathogens with MIC of 9.6–21 μg/mL for bacteria and 85–425 μg/mL for fungi. Almost all of the E. coli cells (99.8%) were killed by the treatment with 42.5 μg/mL of AgNPs at room temperature for 1 h

Boosting thermal conductivity by surface plasmon polaritons propagating along a thin Ti film

We experimentally demonstrate a boosted in-plane thermal conduction by surface plasmon polaritons (SPPs) propagating along a thin Ti film on a glass substrate. Owing to a lossy nature of metal, SPPs can propagate over centimeter-scale distance even with a supported metal film, and resulting ballistic heat conduction can be quantitatively validated. Further, for a 100-nm-thick Ti film on glass substrate, a significant enhancement of in-plane thermal conductivity compared to bulk value ($\sim 35\%$) is experimentally shown. This study will provide a new avenue to employ SPPs for heat dissipation along a supported thin film, which can be readily applied to mitigate hot-spot issues in microelectronics.Comment: 3 figure

Smart fiber orientation monitoring system in a mold via electrical route modeling

The orientation of unidirectional carbon fibers (UDCFs) in a manufacturing process is critical to the mechanical properties of carbon fiber reinforced plastics (CFRPs). This study presents a method to monitor the orientation of UDCFs on a mold using electrical resistance during the CFRP manufacturing process. An equivalent electrical model for UDCFs was proposed to develop an in situ sensor in a mold. The orientation of UDCFs during the CFRP manufacturing process is investigated in terms of its orthotropic electrical properties. The proposed technique can have strong implications on in situ monitoring of composite molding process where the fiber orientation is unseen by monitoring electrical resistance with Cu tapes as electrodes

The tip-of-the-tongue phenomenon in older adults with subjective memory complaints.

In older adults with subjective memory complaints (SMCs), featuring a decline in memory but not exhibiting problems during medical examinations and objective memory tests, the weak links between nodes evident in the word retrieval process can be a primary factor for predicting mild cognitive impairment and dementia. This study examined the frequency of the "Tip-of-the-Tongue" (ToT) phenomenon according to age and subjective memory complaints of older adults, and identified differences in the resolution method using sequential cues. A celebrity naming task was performed on older adults (aged 50 to 79) with SMCs (n = 30) and without SMCs (n = 30), comparing the frequency of the ToT phenomenon and in resolution methods. We found that, even if our subjects with SMCs obtained normal results in the objective neuropsychology test, they experienced a significantly higher frequency of the ToT phenomenon than those without SMCs. In addition, subjects with SMCs showed a significantly lower rate of resolution, both spontaneous and following a syllabic cue, compared to those without SMCs. SMCs can be a very early marker of degenerative diseases causing cognitive dysfunction, and thus the selection of appropriate tools for early detection of SMCs is important. The proper naming task may sensitively detect subclinical symptoms of SMCs in subjects who are not classified as patients with cognitive impairments on general neuropsychological test. In addition, this task can identify weak connections between semantic and phonological nodes due to changes in the neural region of older adults with SMCs

RVMOS: Range-View Moving Object Segmentation Leveraged by Semantic and Motion Features

Detecting traffic participants is an essential and age-old problem in autonomous driving. Recently, the recognition of moving objects has emerged as a major issue in this field for safe driving. In this paper, we present RVMOS, a LiDAR Range-View-based Moving Object Segmentation framework that segments moving objects given a sequence of range-view images. In contrast to the conventional method, our network incorporates both motion and semantic features, each of which encodes the motion of objects and the surrounding circumstance of the objects. In addition, we design a new feature extraction module suitably designed for range-view images. Lastly, we introduce simple yet effective data augmentation methods: time interval modulation and zero residual image synthesis. With these contributions, we achieve a 19% higher performance (mIoU) with 10% faster computational time (34 FPS on RTX 3090) than the state-of-the-art method with the SemanticKitti benchmark. Extensive experiments demonstrate the effectiveness of our network design and data augmentation scheme.FALS

Constitutive modeling and finite element analysis of metastable medium entropy alloy

© 2022 Elsevier B.V.In this study, the constitutive model of metastable ferrous Fe60Co15Ni15Cr10 (at%) medium entropy alloy (FeMEA) was constructed based on deformation-induced martensitic transformation (DIMT) behavior under cryogenic temperature. The crystal structure of the FeMEA gradually transformed from a single face-centered cubic (FCC) phase to a body-centered cubic (BCC) phase during deformation. The critical initiation stress criterion and the volumetric fraction evolution model were employed to describe the DIMT kinetics during uniaxial tensile testing. The flow stress model of the FCC phase as a function of the applied strain was developed using the dislocation-based hardening model, and the BCC phase behavior was evaluated based on the macroscopic behavior of the multiphase material and phase transformation kinetics. The decline in the dislocation mean free path for the FCC phase was associated with the grain refinement of the FCC phase due to the transformed BCC islands. To verify its applicability, the model was compared to the experimental data describing phase transformation kinetics and the mechanical behavior.11Nsciescopu

Cu-Fe계 고강도 비 혼화성(Heterogeneous) 중엔트로피 합금 설계

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Surface heterostructuring of laser-clad 316L stainless steel through texture-driven deformation twinning

© 2022 Acta Materialia Inc.Heterostructured materials produced by surface modification have attracted considerable attention owing to their exceptional mechanical properties. Laser-cladding is one of the promising processes to achieve heterostructures by creating a sandwich structure through a simple process. Herein, we propose a new strategy for designing heterostructured laser-clad materials containing dynamically reinforceable heterogeneity introduced through texture-engineering. The specific processing parameters for laser-cladding of 316L stainless steel were selected to induce a predominant crystallographic orientation favorable for twinning. The textured laser-clad alloy showed different textures between the coating and substrate regions, which exhibited a preferential orientation of and , respectively, along the loading direction. Plastic incompatibility was intensified due to the heterogeneous structure caused by the high dislocation density and localized deformation twinning in the coating region. Consequently, the present laser-clad alloys exhibited superior strength-ductility synergy compared to the other homogeneous materials, owing to the substantial hetero-deformation-induced hardening.11Nsciescopu

Large-scale fabrication method of heterostructured materials using conventional cold-rolling for industrial applications

Heterostructured materials offer great promise as next-generation structural materials, providing excellent combinations of strength and elongation. However, the need for additional equipment for heterostructuring poses challenges for scalability. In this study, we propose a strategy to fabricate heterostructured materials using conventional cold-rolling, eliminating the need for additional pre- or post-treatments. This newly developed method refines only surface grains with shear stress induced by cold-rolling performed at a slight thickness reduction. The cold-rolled samples exhibited improved strengths at the expense of ductility compared to the as-received homogeneous sample, primarily attributed to the heterogeneous strengthening effect and the increased pre-existing dislocation densities. Depending on the cold-rolling process conditions, yield strength increased from 85.6 MPa to 138.6 MPa, and the corresponding elongation loss was 5.5% and 14.8%, respectively. The increase in yield strength of the cold-rolled samples at the same uniform elongation as the as-received sample, calculated using a trend line, was about 51.5 MPa. This proposed strategy has the potential to advance the industrialization of heterostructured materials by enabling large-scale fabrication using conventional processing equipment