Mechanical, thermal, and water absorption properties of HDPE/barley straw composites incorporating waste rubber.

This study investigates the mechanical, thermal, and water absorption properties of high-density polyethylene (HDPE) composites filled with barley straw and varying amounts of waste rubber. The research aims to develop sustainable materials that repurpose agricultural and industrial waste while addressing resource scarcity and waste management challenges. Composites were prepared using a twin-rotor mixer and hydraulic press, with waste rubber content varying from 0 to 20 wt%.

Effect of chitosan-epoxy ratio in bio-based adhesive on physical and mechanical properties of medium density fiberboards from mixed hardwood fibers.

Chitosan and bio-based epoxy resins have emerged as promising formaldehyde-free replacements for traditional urea-formaldehyde (UF) adhesives in engineered wood products. This study evaluated five chitosan-to-epoxy weight ratios (3:1, 2:1, 1:1, 1:2, 1:3) as adhesives for hot-pressing medium density fiberboards (MDF) using mixed hardwood fibers. Increasing the epoxy ratio reduced viscosity and gel time, facilitating spraying and fast curing.

Testing of Polymer Composites for Manufacturing of Sprayer Nozzles.

Wear is the leading cause of nozzle failure. The durability of the nozzle is affected by the material it is made from. Traditional materials are ceramics, stainless steel, brass, and polymers.

Case Study of Diesters of o-Phthalic Acid in Surface Waters with Background Levels of Pollution.

Lake Baikal was studied as a model for elucidating the general pattern of -phthalic acid diester (PAE) distributions in surface waters with background pollution levels. The influence of factors including congeners, concentrations, sampling points, seasons, years, and potential sources was considered and the environmental risk for various hydrobionts was established. Priority PAEs in Baikal waters are represented by dimethyl phthalate (DMP), diethyl phthalates (DEP), di--butyl phthalate (DBP) and di-(2-ethylhexyl)phthalate (DEHP).

Game of Aliphatics: A Density Functional Theory Study of Base-Catalyzed Substrate-Controlled Dimerizations of Aliphatic Alkynones.

The present work focuses on a comprehensive density functional theory (DFT) study of newly discovered base-catalyzed substrate-controlled dimerizations of aliphatic alkynones. In order to understand the origin of selectivity of the cascade assemblies of 6-methylene-5-oxaspiro[2.4]heptanones and 2-alkenylfurans, structural and electronic properties of neutral and deprotonated alkynone molecules, thermodynamic and kinetic characteristics of the deprotonation of alkynones having diverse C-H active substituents at the carbonyl function under the action of a base, and thermodynamic and kinetic characteristics of possible mechanisms of the discussed cascade reactions were theoretically assessed.

Assessment of stable carbon isotope С/С ratio in phthalates from surface waters using HPLC-HRMS-TOF approach.

A method for estimating the ratio of stable carbon isotopes С/С in the composition of phthalates from surface water at a trace concentration level is proposed. It is based on the concentration of hydrophobic components of water using an analytical reversed phase HPLC column followed by their gradient separation and detection of eluted phthalates using a high-resolution time-of-flight mass spectrometer (ESI-HRMS-TOF) in the form of molecular ions. The ratio of stable carbon isotopes С/C in phthalates is calculated as a ratio of integrals under the monoisotopic [M+1+H] and [M+H] peaks.

Water Quality, Toxicity and Diversity of Planktonic and Benthic Cyanobacteria in Pristine Ancient Lake Khubsugul (Hövsgöl), Mongolia.

For the first time, microcystin-producing cyanobacteria have been detected in Khubsugul, which is ancient, pristine and one of the world's largest lakes. The microcystin synthetase genes belonged to the genera , and possibly spp. No microcystins were found in the water of the lake.

Densification and Proton Conductivity of LaBaScO Electrolyte Membranes.

Bain LaBaScO impairs sintering and leads to a decrease in its ceramic density. Two approaches have been studied for obtaining dense ceramics: using a high processing temperature and the introduction of a CoO sintering additive. An addition of only 0.

By-Products from Food Industry as a Promising Alternative for the Conventional Fillers for Wood-Polymer Composites.

The present paper describes the application of two types of food-industry by-products, brewers' spent grain (BSG), and coffee silverskin (ŁK) as promising alternatives for the conventional beech wood flour (WF) for wood-polymer composites. The main goal was to investigate the impact of partial and complete WF substitution by BSG and ŁK on the processing, structure, physicochemical, mechanical, and thermal properties of resulting composites. Such modifications enabled significant enhancement of the melt flowability, which could noticeably increase the processing throughput.

Theoretical Density Functional Theory Study of Electrocatalytic Activity of MN-Doped (M = Cu, Ag, and Zn) Single-Walled Carbon Nanotubes in Oxygen Reduction Reactions.

The mechanism of oxygen reduction reaction (ORR) on transition metal-doped nitrogen codoped single-walled nanotubes, CHMN (MN-CNT where M = Zn, Cu, or Ag; N = pyridinic nitrogen), has been studied with the density functional theory method at the ωB97XD/DGDZVP level of theory. The charge density analysis revealed two active sites of the catalyst toward ORR: the MN site and the C=C bond of the N-C=C-N metal-chelating fragment (C site). The structure of O-containing adsorbates (O , HOO*, O*, HO*, etc.

Trifluoromethanesulfonamide vs. Non-Fluorinated Sulfonamides in Oxidative Sulfamidation of the C=C Bond: An In Silico Study.

A theoretical analysis of the reaction of oxidative sulfamidation of several alkenes was performed in order to explain the various experimental observations and different reactivity of triflamide and non-fluorinated sulfonamides. Transformations occurring in the system alkene-sulfonamide in the presence of oxidative system (BuOCl + NaI) were analyzed at the MP2/DGDZVP//B3LYP/DGDZVP level of theory using the IEF-PCM method for taking into account the solvent acetonitrile (MeCN) effect. As the model substrates, styrene, trimethyl(vinyl)silane, dimethyl(divinyl)silane and diphenyl(divinyl)silane were chosen and mesylamide, triflamide, tosylamide and -nosylamide were taken as the reagents.

Single Si-Doped Graphene as a Catalyst in Oxygen Reduction Reactions: An In Silico Study.

Single Si-doped graphene CHSi with one carbon atom replaced by a three-coordinate silicon atom is studied by density functional theory (DFT) calculations as a catalyst for the oxygen reduction reactions (ORRs) in both acidic and alkaline media. The active sites for oxygen adsorption were determined from the distribution of the charge density difference analysis. At the equilibrium electrode potential, the most stable intermediate was found to have the structure HO*O*-CHSi with both oxygen atoms bound to the support, one of them being incorporated in between Si and C atoms, corresponding to the transfer of one hydrogen atom [H + e].

Water Uptake and Transport Properties of LaCaScO Proton-Conducting Oxides.

In this study, oxide materials LaCaScO (x = 0.03, 0.05 and 0.

Extensive Contamination of Water with Saxitoxin Near the Dam of the Irkutsk Hydropower Station Reservoir (East Siberia, Russia).

An area of discolored water 50 m wide and 30 m long was found in September 2017 close to the dam of the Irkutsk hydroelectric power station. Water from this spot was sampled for investigation in the present study. Microscopic analysis revealed that the suspended matter in the sample was composed of clumps of filaments, vegetative cells, akinetes and heterocysts that formed short filaments and solitary cells.

Cyanobacteria from Abyssal Benthos of Lake Baikal: Unique Ecology and Metabolic Potential.

A strain of was isolated from the bottom sediments of the oil seep at Gorevoy Utes (Central Baikal) at a depth of 890 m. The Baikal strain is highly similar (98-99%) to the CCAP 1453/9 strain and the typical PCC 73103 strain isolated from soil ecotopes. Based on the analysis of functional genes and mass spectrometry data, we determined that the strain can produce bioactive peptides and polyketides, but does not produce known cyanobacterial toxins, saxitoxin or its analogs, or microcystins.

First detection of benthic cyanobacteria in Lake Baikal producing paralytic shellfish toxins.

Cyanobacteria were screened from the surface of diseased sponges, stone and bedrock in Lake Baikal for the presence of saxitoxin using enzyme-linked immunosorbent assay. In sequel, eight paralytic shellfish toxin (PST) variants were identified using a MALDI mass spectrometry. Microscopic examination found that Tolypothrix distorta dominated in the biofouling samples.

Ionofore antibiotic polynactin produced by Streptomyces sp. 156A isolated from Lake Baikal.

The potential antibacterial activity of secondary metabolites produced by Streptomyces sp. 156A isolated from Lake Baikal was investigated. The selective liquid-liquid extraction method was applied to obtain a mixture of nactins (polynactin) produced by the strain.