Development of vibration damping materials based on butyl rubber: A study of the phase equilibrium,rheological, and dynamic properties of compositions

A detailed study of butyl rubber-based vibration damping formulations linking their composition, morphology, phase structure, viscosity, mechanical loss factor, and other characteristics is presented for the first time. High performance of the compositions including aromatic petroleum oil is explained by limited solubility of the plasticizer that leads to the formation of a highly-viscous emulsion (η_20°C ≈ 1000 Pa·s) consisting of a swollen butyl rubber matrix and dispersed oil droplets in the broad composition range. Chalk is found to be the best inorganic filler as its spherical particles provide strong adhesion to the reinforcing layer of aluminum foil. Aiming to eliminate ecologically unfriendly aromatic compounds, a new low-cost binding agent formulation based on butyl rubber mixed with polyisobutylene and highly refined mineral oil is suggested. Being environmentally safe, it possesses high viscosity of 1000–3000 Pa·s, cohesion strength of 3.5–5.0 N/cm, penetration of 4.5–6.0 mm, and mechanical loss factor up to 0.34 at room temperature, which are as good as, or even better than, the properties of currently produced vibration damping materials containing aromatic compounds. New materials can be used in car and aircraft parts for effective vibration isolation.     

The Interfacial Interactions of Glycine and Short Glycine Peptides in Model Membrane Systems

The interactions of amino acids and peptides at model membrane interfaces have considerable implications for biological functions, with the ability to act as chemical messengers, hormones, neurotransmitters, and even as antibiotics and anticancer agents. In this study, glycine and the short glycine peptides diglycine, triglycine, and tetraglycine are studied with regards to their interactions at the model membrane interface of Aerosol-OT (AOT) reverse micelles via ¹H NMR spectroscopy, dynamic light scattering (DLS), and Langmuir trough measurements. It was found that with the exception of monomeric glycine, the peptides prefer to associate between the interface and bulk water pool of the reverse micelle. Monomeric glycine, however, resides with the N-terminus in the ordered interstitial water (stern layer) and the C-terminus located in the bulk water pool of the reverse micelle.     

Some Molecular and Cellular Stress Mechanisms Associated with Neurodegenerative Diseases and Atherosclerosis

Chronic stress is a combination of nonspecific adaptive reactions of the body to the influence of various adverse stress factors which disrupt its homeostasis, and it is also a corresponding state of the organism’s nervous system (or the body in general). We hypothesized that chronic stress may be one of the causes occurence of several molecular and cellular types of stress. We analyzed literary sources and considered most of these types of stress in our review article. We examined genes and mutations of nuclear and mitochondrial genomes and also molecular variants which lead to various types of stress. The end result of chronic stress can be metabolic disturbance in humans and animals, leading to accumulation of reactive oxygen species (ROS), oxidative stress, energy deficiency in cells (due to a decrease in ATP synthesis) and mitochondrial dysfunction. These changes can last for the lifetime and lead to severe pathologies, including neurodegenerative diseases and atherosclerosis. The analysis of literature allowed us to conclude that under the influence of chronic stress, metabolism in the human body can be disrupted, mutations of the mitochondrial and nuclear genome and dysfunction of cells and their compartments can occur. As a result of these processes, oxidative, genotoxic, and cellular stress can occur. Therefore, chronic stress can be one of the causes forthe occurrence and development of neurodegenerative diseases and atherosclerosis. In particular, chronic stress can play a large role in the occurrence and development of oxidative, genotoxic, and cellular types of stress.     

两台煤立磨无法同时运行原因分析及解决措施

为了实现万吨生产线产能扩大后的用煤量需求，单台煤立磨产量已无法满足，面对同时运转两台煤立磨出现的问题，逐步进行分析，查找原因，通过将入磨热风管一分为二，解决了风量分配不均、工况波动造成的磨机振动跳停等一系列问题，效果显著。     

Effect of the Curvature of a Spherical Flame on Its Speed: Comparison of Two Approaches

Combustion, Explosion, and Shock Waves - Two approaches to describing an expanding spherical flame are compared. Processing of a large amount of experimental data shows that the approach using as a...     

Low/intermediate temperature pyrolyzed polysiloxane derived ceramics with increased carbon for electrical applications

This study focuses on the chemistry, thermal stability, and electrical conductivity of low/intermediate pyrolysis temperature (700?900 °C) polysiloxane derived ceramics. These ceramics were modified with additional carbon derived from divinylbenzene (DVB) added to the precursor. Their electrical properties were investigated for potential uses in micro-electrical mechanical systems (MEMS) and anodes for lithium batteries. The microstructure and chemical composition was investigated by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), Raman spectroscopy, and x-ray photoelectron spectroscopy (XPS); thermogravimetric analysis (TGA) provided insight into the thermal stability; and electrochemical impedance spectroscopy (EIS) into the electrical properties of the material. The increase of pyrolysis temperature and carbon content lead to an enhancement of the electrical conductivity, higher than previously reported values for intermediate pyrolysis temperature SiOC polymer derived ceramics. A limit of the amount of DVB that can be added to PHMS to produce a hybrid precursor has also been obtained.     

Blockchain for Collaborative Businesses

Mobile Networks and Applications - Blockchain applications have continuously improved ever since its first debut on cryptocurrency. From then on, its uses have branched out from the financial...     

Photocatalytic degradation of methylene blue and sulfisoxazole from water using biosynthesized zinc ferrite nanoparticles

The extensive occurrence of textile and pharmaceutical contaminants and their metabolites in water systems has posed significant concerns regarding their possible threat to human health and the environmental system. As a result, herein ZnFe₂O₄ nanoparticles were synthesized through the use of Monsonia burkeana plant extract. The synthesized nanoparticles were characterized using XRD, FTIR, UV–vis, SEM, EDS, TGA, BET, PL, EPR and VSM. XRD showed that the crystalline structure of ZnFe₂O₄ nanoparticles with a calculated crystal size of 25.03 nm was formed. FT-IR confirmed the characteristic functional groups contained within the M. burkeana plant were deposited on the formed ferrite nanoparticles. BET analysis confirmed the mesoporous nature of ZnFe₂O₄ with an average pore diameter of 31.6 nm. Morphological studies demonstrated that the formed nanoparticles had spherical as well as rod-like shapes. ZnFe₂O₄ photocatalyst illustrated that it may be effortlessly detached by an external magnetic field. The optimum conditions for the 99.8% removal of Methylene Blue was obtained at pH12, within 45min and at the optimum dosage of 25 mg of the catalyst. The as-prepared ZnFe₂O₄ nanoparticles proved to be easily separated and recycled, and remained efficient even after 5 reuses, proving that the material is highly stable. The ROS studies also demonstrated that electrons are the main factors contributing to the degradation of MB. Upon testing the photocatalytic performance of the sulfonamide antibiotic, sulfisoxazole in water showed a degradation of 67%. This study has shown that these materials can be used in targeting textile and pharmaceutically polluted water.     

A novel ceramic matrix composite based on YNbO4–TiO2 for microwave applications

This work presents the dielectric properties of YNbO₄ (YNO)–TiO₂ composites in the microwave range. X-ray diffraction analysis demonstrates that the addition of TiO₂ to YNO results in the formation of a Y(Nb_0.5Ti_0.5)₂O₆ phase. In the microwave range, the values of permittivity and dielectric loss did not present major changes with the increment of TiO₂. Moreover, the addition of TiO₂ results in an improvement in the thermal stability of YNO, with YNO63 demonstrating a resonant frequency of ?8.96 ppm.°C^?1. We utilised numerical simulations to evaluate the behaviour of these materials as dielectric resonator antennae and it is found that they exhibit a reflection coefficient below ?10 dB at the resonant frequency, with a realised gain of 4.94 – 5.76 dBi, a bandwidth of 665–1050 MHz and a radiation efficiency above 84%. Our results indicate that YNO–TiO₂ composites are interesting candidates for microwave operating devices.