Comparative Study of Metakaolin and Zeolite Tuff Influence on Properties of High-Strength Concrete

Composite admixtures which include active pozzolanic components and high-range water reducers, allows to obtain high-strength, particularly dense and durable concrete to achieve a reduction in resources and energy consumption of manufacturing.Zeolite, containing a significant amount of active silica, can serve as one of the alternative substances to resources and energy consuming mineral admixtures like metakaolin and silica fume. The deposits of zeolites are developed in Transcarpathia (Ukraine), USA, Japan, New Zealand, Iceland and other countries. It is known that zeolite tuffs exhibit pozzolanic properties and are capable to substitution reactions with calcium hydroxide.However, the high dispersion of zeolite rocks leads to a significant increase in the water consumption of concrete. Simultaneous introduction of zeolite tuffs with superplasticizers, which significantly reduce the water content, creates the preconditions for their effective use in high-strength concrete.Along with dehydrated (calcined) zeolite, natural (non-calcined) zeolite expresses itself as an effective mineral admixture of concrete. When using non-calcined zeolite, the effect of increasing in compressive strength at the age of 3 and 7 days is close to the effect obtained when using dehydrated zeolite: 8-10% and 10- 12%, respectively, and 28 days the strength growth is 13-22%. The use of non-calcined zeolite has a significant economic feasibility, so it certainly deserves attention. There were compared the effect of zeolite to metakaolinThe results of the research indicate that the use of composite admixtures, consisted of calcined (non-calcined) zeolite tuff of high dispersity and superplasticizer of naphthalene formaldehyde type, allows to obtain concretes classes C50…C65.

Bacterial extracellular electron transfer: a powerful route to the green biosynthesis of inorganic nanomaterials for multifunctional applications

Synthesis of inorganic nanomaterials such as metal nanoparticles (MNPs) using various biological entities as smart nanofactories has emerged as one of the foremost scientific endeavors in recent years. The biosynthesis process is environmentally friendly, cost-effective and easy to be scaled up, and can also bring neat features to products such as high dispersity and biocompatibility. However, the biomanufacturing of inorganic nanomaterials is still at the trial-and-error stage due to the lack of understanding for underlying mechanism. Dissimilatory metal reduction bacteria, especially Shewanella and Geobacter species, possess peculiar extracellular electron transfer (EET) features, through which the bacteria can pump electrons out of their cells to drive extracellular reduction reactions, and have thus exhibited distinct advantages in controllable and tailorable fabrication of inorganic nanomaterials including MNPs and graphene. Our aim is to present a critical review of recent state-of-the-art advances in inorganic biosynthesis methodologies based on bacterial EET using Shewanella and Geobacter species as typical strains. We begin with a brief introduction about bacterial EET mechanism, followed by reviewing key examples from literatures that exemplify the powerful activities of EET-enabled biosynthesis routes towards the production of a series of inorganic nanomaterials and place a special emphasis on rationally tailoring the structures and properties of products through the fine control of EET pathways. The application prospects of biogenic nanomaterials are then highlighted in multiple fields of (bio-) energy conversion, remediation of organic pollutants and toxic metals, and biomedicine. A summary and outlook are given with discussion on challenges of bio-manufacturing with well-defined controllability.

Role of Gold Nanoparticles in Drug Delivery and Cancer Therapy

Among various nanoparticles (NPs), gold nanoparticles (GNPs) gained valuable attention in the field of medicine because of some unique properties like small size and high surface area-to-volume ratio, inert nature, stability, high dispersity, non-cytotoxicity, and biocompatibility. These NPs are evolving as promising agents especially in drug carriers, cancer therapy, and constantly being exploring as photothermal agents, contrast agents, and radiosensitisers. Besides, GNPs interact with thiols that provides an effective and selective means of controlled intracellular release. At the present, cancer patients are increasing rapidly at national and international levels. In this chapter, efforts have taken to highlight the importance of GNPs, their critical mediation in drug delivery, as sensors for probing and imaging tumors and anti-angiogenesis. More importantly, this short piece of analysis highlights the photothermal effect of GNPs in therapy and as radiosensitizers. Finally, the current challenges and future perspectives of GNP's in cancer management are also discussed.

A structured catalyst with high dispersity of Au species based on hollow SiC foam with porous walls for acetylene hydrochlorination

A bidirectional drying to achieve high dispersity of structured catalysts using hollow SiC foam with porous walls.

Amino Functionalization of Zirconium Diboride for High Dispersion Stability and Solid Loading

Zirconium diboride (ZrB2) is an ultrahigh-temperature ceramic (UHTC) with excellent thermal and mechanical properties. To fabricate a complexly structured UHTC sintered body with high density a high-solid-loading slurry with low viscosity is required to fill the mold well. Extensive studies have been carried out to improve the dispersion properties, including those on solvents and surfactants. In this study, a surface treatment using polyethylenimine (PEI) was investigated. This reagent was used to provide ZrB2 particles with desirable properties, such as electrostatic repulsive force and steric hindrance, by the functionalization of amine groups. Additionally, surface treatments with different concentrations of PEI were performed. The appropriate content for a high dispersity was determined. The surface functional groups of the PEI-treated ZrB2 were observed by Fourier-transform infrared spectroscopy. The surface charge and enhancement in dispersion were evaluated by zeta potential and particle size distribution analysis, respectively. The rheological properties of the ZrB2 slurries with various solid loadings were analyzed by viscosity measurements. In conclusion, ZrB2 slurries with solid loadings up to 50 vol% could be prepared through the PEI treatments.

Silver, Gold, and Silver-Gold Bimetallic Nanoparticle-Decorated Dextran: Facile Synthesis and Versatile Tunability on the Antimicrobial Activity

The noble metal-based nanoparticles (NPs) have been considered as potential antimicrobial agents because of their good antibacterial and antifungal activities as well as biocompatible nature. In this study, we have introduced a simple and fast route to synthesize silver, gold, and silver-gold bimetallic NP-decorated dextran. The as-synthesized noble metal-based NPs with spherical geometry showed high dispersity in dextran. The antibacterial and antifungal of obtained nanomaterials were tested with Xanthomonas oryzae pv. oryzae (Xoo) bacteria and Magnaporthe grisea (M. grisea) fungi. The silver NPs and bimetallic NPs with high silver content in dextran exhibited excellent activity to inhibited the growth of the bacteria and fungi, whereas the gold/dextran has weak antimicrobial effects. The antibacterial and antifungal properties of silver-gold bimetallic NPs in dextran biopolymer can be tuned according to the content of silver in the bimetallic NPs. The obtained nanomaterials could open an entry to a new class of antibiotics.

Concurrent Control over Sequence and Dispersity in Multiblock Copolymers

<p>Controlling monomer sequence in synthetic macromolecules is a major challenge in polymer science and the order of building blocks has already been demonstrated to determine macromolecular folding, self-assembly and fundamental polymer properties. Dispersity is another key parameter in material design, with both low and high dispersity polymers displaying complementary properties and functions. However, synthetic approaches that can simultaneously control both sequence and dispersity remain experimentally unattainable. Here we report a simple, one pot, and rapid synthesis of sequence-controlled multiblocks with on demand control over dispersity while maintaining high livingness, excellent agreement between theoretical and experimental molecular weights and quantitative yields. Key to our approach is the regulation in chain transfer agent activity during controlled radical polymerization that enables the preparation of multiblocks with gradually ascending (<i>Ɖ</i>=1.16 →1.60), descending (<i>Ɖ</i>=1.66 →1.22), alternating low and high dispersity values (<i>Ɖ</i>=1.17 →1.61 →1.24 →1.70 →1.26) or any combination thereof. The enormous potential of our methodology was further demonstrated through the impressive synthesis of highly ordered pentablock, octablock and decablock copolymers yielding the first generation of multiblocks with concurrent control over both sequence and dispersity.</p>

Concurrent Control over Sequence and Dispersity in Multiblock Copolymers

<p>Controlling monomer sequence in synthetic macromolecules is a major challenge in polymer science and the order of building blocks has already been demonstrated to determine macromolecular folding, self-assembly and fundamental polymer properties. Dispersity is another key parameter in material design, with both low and high dispersity polymers displaying complementary properties and functions. However, synthetic approaches that can simultaneously control both sequence and dispersity remain experimentally unattainable. Here we report a simple, one pot, and rapid synthesis of sequence-controlled multiblocks with on demand control over dispersity while maintaining high livingness, excellent agreement between theoretical and experimental molecular weights and quantitative yields. Key to our approach is the regulation in chain transfer agent activity during controlled radical polymerization that enables the preparation of multiblocks with gradually ascending (<i>Ɖ</i>=1.16 →1.60), descending (<i>Ɖ</i>=1.66 →1.22), alternating low and high dispersity values (<i>Ɖ</i>=1.17 →1.61 →1.24 →1.70 →1.26) or any combination thereof. The enormous potential of our methodology was further demonstrated through the impressive synthesis of highly ordered pentablock, octablock and decablock copolymers yielding the first generation of multiblocks with concurrent control over both sequence and dispersity.</p>