Papers by Keyword: Reaction

Abstract: The interaction of magnesium carbonate with polyphenylsiloxane under the conditions of mechanochemical activation with subsequent heating has been investigated. Based on the TGA and DTA data, it has been shown that, upon heating up to 420°C, the reaction proceeded completely with the release of carbon dioxide. The polymer was dissolved in DMFA and purified by repeated precipitation with water. The polymer yield was 64%. The residue insoluble in organic solvents has been obtained by evaporation of an aqueous solution. The composition and structure of the synthesis products have been analyzed by means of element analysis, IR spectroscopy, and diffractometry. It has been demonstrated that the fraction soluble in DMFA had a silicon-to-magnesium ratio equal to 4.2, while the fraction isolated from water had this ratio equal to 1.0. The IR and XRD data enabled one to conclude that, regardless of the different compositions, the structures of all fractions were similar and corresponded to mesomorphic layered polymers produced by the ion exchange method.

Abstract: We have studied the influence of oxidation-reduction reactions on the structure and strength behavior of the Kachkanar fluxed pellets both in their initial condition and during reduction. It has been discovered that at heating rates and temperatures found in industrial units the roasted pellets that are not oxidized to a full extent and are characterized by zonal structure do not meet the requirements imposed for the blast-furnace smelting raw materials. To develop a process that would ensure high metallurgical properties, we have analyzed the hematite dissociation reaction. It was found that the temperature and the content of slag-forming oxides influence this reaction. A sinter pot was used to carry out the research and determine metallurgical properties of partially dissociated pellets. The obtained results helped to develop a process to dissociate hematite at lower temperatures with calcium ferrosilicate melt. Such pellets are reduced at the temperatures of over 700^оС, which prevents their destruction in blast furnaces.

Abstract: Using solid-to-solid couples investigation, this study characterized the reaction products evolved and quantified the diffusion kinetics when pure Mg bonded to AA6061 is subjected to thermal treatment at 300°C for 720 hours, 350°C for 360 hours, and 400°C for 240 hours. Characterization techniques include optical microscopy, scanning electron microscopy with X-ray energy dispersive spectroscopy, and transmission electron microscopy. Parabolic growth constants were determined for γ-Mg₁₇Al₁₂, β-Mg₂Al₃, and the elusive ε-phase. Similarly, the average effective interdiffusion coefficients of major constituents were calculated for Mg (ss), γ-Mg₁₇Al₁₂, β-Mg₂Al₃, and AA6061. The activation energies and pre-exponential factors for both parabolic growth constant and average effective interdiffusion coefficients were computed using the Arrhenius relationship. The activation energy for growth of γ-Mg₁₇Al₁₂ was significantly higher than that for β-Mg₂Al₃ while the activation energy for interdiffusion of γ-Mg₁₇Al₁₂ was only slightly higher than that for β-Mg₂Al₃. Comparisons are made between the results of this study and those of diffusion studies between pure Mg and pure Al [1] to examine the influence of alloying additions in AA6061.

Abstract: The paper deals with the clamping fixture jaws procedure design. The clamping jaw design methodology developed summarizes complex factors. These factors affect the clamping jaws design for the workpiece. Methodical design procedure consists of three stages. Namely, there are input date summary, clamping fixture design and the last design verification. The ANSYS simulation was used for the verification developing methodology. The components model simulation aim has been studied impact of clamping force position change to the cutting force reactions change. Research was conducted with different positions of jaws.

Abstract: Retired Athletes reemployment problem is a long-term big problem. Combined with the characteristics of Chinese sports system, the retired athletes retired various emotional and behavioral reactions of transition during the intervention support, help the athletes to role positioning, the establishment of a new way of life, to develop good habits, to establish and the social network to adapt to the new. All of these aspects of psychological support can be transformed into transition resources, forming applied to retire the ready state, and dynamically active influence retirement transition stage.

Abstract: Ductile Iron has been a great material in water carrying pipes, heavy duty parts of farm equipment and other heavy applications. This work looked into the corrosion rate of ductile iron in different environments of usage and storage for a period of six (6) months. The environments were outside air, air conditioned (A/C) environment, brackish (salty) and alkaline environments. The results showed that as the period of exposure increases the corrosion rate decreases. There was a sharp corrosion rate at the first few months for all the environments but as the month increases the corrosion slows down. Brackish (NaCl) environment had the highest weight loss with a difference (last month initial month) of 1.1456g followed by outside environment with a difference of 1.0284g while A/C had the lowest with zero.

Abstract: Detonation pressure profiles in TNT/RDX and its mixtures with aluminum powders of different particle size have been studied with Manganin piezoresistance gauge. The measured detonation pressure accorded with the calculated detonation pressure. The results show that micrometer aluminum powders reacted with detonation at times of 0.5μs after the peak pressure. Aluminum powders did not react in the detonation zone, and introducing aluminum into explosive would reduce the detonation pressure. Compare with micrometer aluminum powders, nanometer aluminum powders reacted with detonation product more quickly.

Abstract: Synthesis process of ZrAl₃O₃N was investigated by non-pressure sintering at 1600 °C in N₂ atmosphere according to five drafted equations. The influences of the atmosphere and material combination on the synthetic effect of ZrAl₃O₃N were preliminarily discussed by XRD. The results showed that atmosphere was a key factor that determined whether ZrAl₃O₃N could be synthesized, i.e. ZrAl₃O₃N could only be synthesized in high purity N₂ atmosphere, and that ZrAl₃O₃N was only synthesized on condition that the raw material composition included both AlN powder and nano-ZrO₂ powder. However, with increasing of AlN content, the XRD peaks of ZrAl₃O₃N and ZrN phase gradually reduced, and pure ZrAl₃O₃N was hardly obtained by in-situ reaction between AlN and ZrO₂ because of generation of ZrN as well.

Abstract: In the paper, the reaction of solid-solid model was researched and we confirmed the reaction equation. The experiments in the lab shown that the t1/2 is 11.8min in the ferrosilicon reduction boron anhydride reaction at low temperature. The yield of boron is higher by direct reduction method smelting. In the boron oxide reducing experiment, the yield minimum is 76%, the maximum is 82%, and the average value is about 79%, which provides favorable foundation conditions for smelting amorphous mother alloy.

Abstract: Calcium carbonate (CaCO₃) is abundant in nature, and is also an important material applied in industry as pigment, filler material, etc. It is a challenge to control the desired CaCO₃ properties for industry applications. In this study, three typical morphologies of CaCO₃, calcite, aragonite and vaterite were prepared. The crystallization temperature and addition of acrylic-acrylate-sulfosalt copolymer play a significant effect on the polymorph change of CaCO₃ sediment. Higher temperature promoted the formation of aragonite, while more additives tended to form the vaterite. The x-ray diffraction and scanning electron microscope analysis confirmed the formation of CaCO₃ with various polymorphs.