Reasons for Reduced Moisture Resistance of Sulfur-Extended Asphalt Concrete

The paper presents the results of a study of the mechanism for reducing the moisture resistance of sulfur-extended asphalt concrete. It is shown that a decrease in moisture resistance occurs due to the occurrence of chemical and physical processes. At the same time, it was found that during the manufacture of sulfur-bitumen composites, toxic gases H2S and SO2 are formed, which are capable of interacting with a mineral filler, as well as the interaction of sulfur with a mineral powder with the formation of sulfur-containing water-soluble salts, the extraction of which leads to a decrease in the moisture resistance of sulfur-bitumen materials. The change in the rate of leaching of these substances from the composite is due to the physical process caused by the crystallization of sulfur and the formation of a capillary structure, which significantly increases the rate of leaching of calcium and magnesium salts, which are products of dissolution or hydrolytic decomposition of water-soluble products of the interaction of sulfur, H2S and SO2 gases with calcium and magnesium carbonates. The intensity of chemical and physical processes intensifies with an increase in the amount of sulfur in sulfur-bitumen materials.

Fabrication of Six Manganese Containing Polyoxometalate Modified Graphite C3N4 Nanosheets Catalysts Used to Catalyze Water Decomposition

With the increase in gas population, the demand for clean and renewable energy is increasing. Hydrogen energy has a high combustion conversion energy while water is its combustion product. In recent years, a way to convert water into hydrogen and oxygen has been found by human beings inspired by plant photosynthesis. However, water decomposition consumes a significant amount of energy and is expensive. People expect to obtain a water decomposition catalyst with low cost and high efficiency. This work selected a six-manganese containing polyoxometalate with a similar structure characteristic to photosynthesizing PSII to fabricate with graphite C3N4 nanosheets for the construction of composite film (Mn6SiW/g-C3N4NSs) electrode via layer by layer self-assembly technology, which was used for the photo-electrochemical decomposition of water under visible light conditions. The binary composite film electrode displayed good catalytic efficiency. The photoelectric density of the composite electrode is 46 μA/cm2 (at 1.23 V vs. Ag/AgCl) and 239 μA/cm2 (at 1.5 V vs. Ag/AgCl). Compared with the g-C3N4NSs electrode alone, the photoelectric density of the composite electrode increased by 1 time. The reason is attributed to the fact that Mn6SiW has a similar structure characteristic to photosynthesizing PSII and high electron transferability. The construction of the composite film containing low-cost Mn6SiW to modify g-C3N4NSs can effectively improve the photocatalytic decomposition of water, thus this study provides valuable reference information for the development of low-cost and high-performance photo-electrocatalytic materials.

Hydrogen Production From Water Under UV Radiation with Carbon Dioxide Mediation

A simple method of hydrogen production through the decomposition of water subjected to UV radiation is presented. Water contained dissolved sodium hydroxide and the solution was saturated with carbon dioxide gas. During saturation, the pH value dropped from about 11.5 to 7-8. The produced bicarbonate and carbonate ions acted as scavengers for hydroxyl radicals, preventing recombination of hydroxyl and hydrogen radicals, and giving priority to the formation of hydrogen gas.In the presented method, the production of hydrogen is combined with the utilization of carbon dioxide.

Assessment of bone marrow fat fractions in the mandibular condyle head using the iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL-IQ) method

The prevalence of temporomandibular joint disorder (TMD) is gradually increasing, and magnetic resonance imaging (MRI) is becoming increasingly common as a modality used to diagnose TMD. Edema and osteonecrosis in the bone marrow of the mandibular condyle have been considered to be precursors of osteoarthritis, but these changes are not evaluated accurately and quantitatively on routine MRI. The iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL-IQ) method, as a cutting-edge MRI technique, can separate fat and water using three asymmetric echo times and the three-point Dixon method. The purpose of this study was to analyze the quantitative fat fraction (FF) in the mandibular condyle head using the IDEAL-IQ method. Seventy-nine people who underwent MRI using IDEAL-IQ were investigated and divided into 1) the control group, without TMD symptoms, and 2) the TMD group, with unilateral temporomandibular joint (TMJ) pain. In both groups, the FF of the condyle head in the TMJ was analyzed by two oral and maxillofacial radiologists. In the TMD group, 29 people underwent cone-beam computed tomography (CBCT) and the presence or absence of bony changes in the condylar head was evaluated. The FF measurements of the condyle head using IDEAL-IQ showed excellent inter-observer and intra-observer agreement. The average FF of the TMD group was significantly lower than that of the control group (p < 0.05). In the TMD group, the average FF values of joints with pain and joints with bony changes were significantly lower than those of joints without pain or bony changes, respectively (p < 0.05). The FF using IDEAL-IQ in the TMJ can be helpful for the quantitative diagnosis of TMD.

Preparation and Performance Analysis of Ag/ZnO Humidity Sensor

Highly sensitive silver (Ag) modified zinc oxide (ZnO) humidity sensors were prepared by hydrothermal synthesis and the mechanism was studied. Experimental results show that Ag-modified ZnO can effectively enhance the performance of a humidity sensor. Large number of oxygen vacancies and many active sites are generated on the surface when molar ratio of Ag+ to Zn2+ is 1:100, which can accelerate the decomposition of water molecules on surface of the material, thereby improving the response of humidity sensor. Moreover, the linearity of ZnO humidity sensor is greatly improved by silver nanoparticles. Compared with previously reported ZnO-based humidity sensors, Ag/ZnO humidity sensors have a better response (151,700%), good linearity, low hysteresis (3%), and short response/recovery time (36/6 s). At the same time, it is found that the light had little effect on the performance of Ag/ZnO. Therefore, this kind of ZnO sensor with stable performance and excellent performance is expected to be used in the detection of relative humidity in conventional environments.

In Situ Assembly of Bimetallic MOF Composites on IF as Efficient Electrocatalysts for Oxygen Evolution Reaction

Since the complicated multiple electron transfer process and slow kinetics in the OER process seriously hinder the electrochemical decomposition of water, it is urgent to design and develop electrocatalyst with...

Investigation of structural and optical properties of zirconia dioxide nanoparticles by radiation and thermal methods

The X-ray diffraction (XRD) spectrum of the nano-ZrO2 compound was drawn, the crystal structure was determined at room temperature and under normal conditions. Radiation-thermal decomposition of water on nanosized ZrO2 in the temperature range of [Formula: see text]–673 K has been studied by Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. It has been shown that nanosized zirconium dioxide adsorbs water via the molecular and dissociative mechanisms. Intermediate products of the radiation-induced heterogeneous decomposition of water, namely, the molecular oxygen and hydrogen peroxide radical ions, zirconium hydride, and hydroxyl radicals have been detected. A comparative analysis of changes in the absorption bands (ABs) of molecular water and surface hydroxyl groups with temperature has been conducted, and the stimulating role of radiation in the radiation-thermal process of water decomposition has been revealed. With the participation of nano-ZrO2 during the radiation-heterogeneous decomposition of water to reveal the role of unbalanced cargo carriers that play the role of energy carriers under the influence of gamma-quantities in nano-ZrO2 and nano-[Formula: see text] systems paramagnetic centers, their origin and acquisition kinetics learned by the EPR method.