Mechanisms and Critical Technologies of Transport Inhibitor Agent (TIA) throughout C-S-H Nano-Channels

The critical issue of the durability of marine concrete lies in the continuous penetration and rapid enrichment of corrosive ions. Here a new ion transfer inhibitor, as TIA, with calcium silicate hydrate (C-S-H) interfacial affinity and hydrophobicity is proposed through insights from molecular dynamics into the percolation behavior of the ion solution in C-S-H nano-channels and combined with molecular design concepts. One side of the TIA can be adsorbed on the surface of the cement matrix and can form clusters of corrosive ions to block the gel pores so as to resist the ion solution percolation process. Its other side is structured as a hydrophobic carbon chain, similar to a door hinge, which can stick to the matrix surface smoothly before the erosion solution is percolated. It can then change into a perpendicular chain shape to reduce the percolation channel’s diameter and thereby inhibit the percolation when ions meet the inhibitor. Therefore, once the erosion solution contacts TIA, it can quickly chelate with calcium ions and erosion ions at the interface to form clusters and compact pores. In addition, the water absorption, chloride migration coefficient, and chloride content of concrete samples decreased significantly after adding TIA, proving that TIA can effectively enhance the durability of cement-based materials. The structure–activity relationship of ion transfer that is proposed can provide new ideas for solving the critical problems of durability of cement-based materials and polymer molecular design.

Surface Modified Nanocellulose and Its Reinforcement in Natural Rubber Matrix Nanocomposites: A Review

Natural rubber is of significant economic importance owing to its excellent resilience, elasticity, abrasion and impact resistance. Despite that, natural rubber has been identified with some drawbacks such as low modulus and strength and therefore opens up the opportunity for adding a reinforcing agent. Apart from the conventional fillers such as silica, carbon black and lignocellulosic fibers, nanocellulose is also one of the ideal candidates. Nanocellulose is a promising filler with many excellent properties such as renewability, biocompatibility, non-toxicity, reactive surface, low density, high specific surface area, high tensile and elastic modulus. However, it has some limitations in hydrophobicity, solubility and compatibility and therefore it is very difficult to achieve good dispersion and interfacial properties with the natural rubber matrix. Surface modification is often carried out to enhance the interfacial compatibilities between nanocellulose and natural rubber and to alleviate difficulties in dispersing them in polar solvents or polymers. This paper aims to highlight the different surface modification methods employed by several researchers in modifying nanocellulose and its reinforcement effects in the natural rubber matrix. The mechanism of the different surface medication methods has been discussed. The review also lists out the conventional filler that had been used as reinforcing agent for natural rubber. The challenges and future prospective has also been concluded in the last part of this review.

Processing symmetry between visual and auditory spatial representations in updating working memory

Updating spatial representations in visual and auditory working memory relies on common processes, and the modalities should compete for attentional resources. The present study examined the relative dominance of memory updating using incompatible spatial information conveyed from two different cue modalities. Participants maneuvered a designated target on a matrix surface according to visual or auditory stimuli that were simultaneously presented, to identify a terminal location. Prior to the navigation task, the relative perceptual salience of the visual cues was manipulated to be equal, superior, or inferior to the auditory cues. The results demonstrated that visual and auditory inputs competed for attentional resources such that visual/auditory guidance was impaired by incongruent cues delivered from the other modality. Although visual dominance was favored in working memory navigation on average, stimuli of relatively high salience interfered with or facilitated other stimuli regardless of modality, demonstrating the similarity of updating processes in visual and auditory spatial working memory. Furthermore, processing asymmetry can be identified during the encoding of sensory inputs into working memory representations. The present results suggest that auditory spatial updating is comparable to visual spatial updating in that salient stimuli receive a high priority when selecting inputs and are used when tracking spatial representations.

Possible Ways to Improve Interphase Adhesion between Fiberglass and Polyphenylenesulfide

The article presents a scientific review on the development of composite materials based on polyphenylene sulfide and glass fillers. The main ways (finishing of the filler surface, synthesis of a polymer matrix with functional groups, treatment of the filler and polymer matrix surface with a plasma flow) of increasing interfacial adhesion at the glass fiber-polyphenylene sulfide interface are considered.

Impact of Matrix Surface Area on Griseofulvin Release from Extrudates Prepared via Nanoextrusion

We aimed to examine the impact of milling of extrudates prepared via nanoextrusion and the resulting matrix surface area of the particles on griseofulvin (GF, a model poorly soluble drug) release during in vitro dissolution. Wet-milled GF nanosuspensions containing a polymer (Sol: Soluplus®, Kol: Kolliphor® P407, or HPC: Hydroxypropyl cellulose) and sodium dodecyl sulfate were mixed with additional polymer and dried in an extruder. The extrudates with 2% and 10% GF loading were milled–sieved into three size fractions. XRPD–SEM results show that nanoextrusion produced GF nanocomposites with Kol/HPC and an amorphous solid dispersion (ASD) with Sol. For 8.9 mg GF dose (non-supersaturating condition), the dissolution rate parameter was higher for extrudates with higher external specific surface area and those with 10% drug loading. It exhibited a monotonic increase with surface area of the ASD, whereas its increase tended to saturate above ~30 × 10−3 m2/cm3 for the nanocomposites. In general, the nanocomposites released GF faster than the ASD due to greater wettability and faster erosion imparted by Kol/HPC than by Sol. For 100 mg GF dose, the ASD outperformed the nanocomposites due to supersaturation and only 10% GF ASD with 190 × 10−3 m2/cm3 surface area achieved immediate release (80% release within 30 min). Hence, this study suggests that ASD extrudates entail fine milling yielding > ~200 × 10−3 m2/cm3 for rapid drug release, whereas only a coarse milling yielding ~30 × 10−3 m2/cm3 may enable nanocomposites to release low-dose drugs rapidly.

Development and Parametric Optimisation of Pure Magnesium Matrix Surface Composite by Friction Stir Processing

Friction stir processing (FSP) is an emerging method for improving surface properties of materials by composite fabrication. This study aims at optimizing the major FSP parameters and analysis of their real-time influence on the mechanical performance of a surface composite fabricated with Magnesium (Mg) matrix and Titanium Carbide (TiC) as reinforcement. Effects of different process parameters, tool rotational speed, plunge depth, the linear speed of the tool, cooling condition, and number of FSP passes have been examined. Using L27 array, a total of 27 combinations of these process parameters were analyzed by taking microhardness as an output response to find influential parameters by Taguchi's technique. Maximum micro-hardness was achieved when tool rpm of 600, cooling temperature of -10o C, tool feed of 15 mm/min, plunge depth of 0.35 mm, and 3 passes of FSP tool were chosen with the help of Taguchi's method. Analysis of variance indicated that cooling temperature, the tool feed, and the number of passes of the FSP tool were the most significant parameters.

A method of quasi-continuous image formation in observation devices with discrete receivers

The article proposes a new method of quasi-continuous image formation in observation devices with discrete receivers. The increase in the number of spatial sampling points in the object image is provided by intraframe scanning. Scanning is carried out by a photosensitive matrix with a regularly changed (controlled) density of the elementary receivers (CDR-matrix). The CDR-matrix contains identical elementary receivers. They are regularly distributed over the matrix surface. The vertical and horizontal distance between adjacent receivers is a multiple of the size of the elementary receiver. The CDR-matrix becomes equivalent in pixel dimensions to a larger photosensitive matrix. The magnitude of the multiplicity placement of the receivers is chosen by the developer when designing the light-sensitive matrix. The image of the object by the CDR-matrix (a separate frame) is composed of a series of snapshots. Each snapshot is formed by signals coming from all elementary receivers of the CDR-matrix. The number of snapshots in the frame is set by the multiplicity of the size of the elementary receivers vertically and horizontally. While using intraframe scanning, the CDR-matrix with a pixel size of the video format can operate in the mode of a photosensitive matrix with a pixel size of 2.5 MP. A CDR-matrix with a pixel size of 6 MP can operate as a 48 MP matrix of a conventional design. A mechanism for storing a frame with observation results when using a CDR-matrix is proposed. It assumes the use of the matrix addition operation. The signal matrix of the observed frame is considered as the sum of the signal matrices of all the snapshots in the frame. Application of the developed method will make it possible to multiply the pixel size of the image relative to the pixel size of the controllable photosensitive matrix. The advantages of the proposed method also include the absence of a mandatory decrease in the effective area of an elementary receiver with an increase in their number in the photosensitive matrix; simplification of hardware measures to reduce the effect of image shift on its quality; absence of information losses in the intervals between adjacent elementary receivers.