AIMS Materials Science最新文献

This study reveals the crease deviation behavior through the developed forming simulation. A combination resistance model was expanded and applied to simulate the 180° folding process of a creased paperboard, using the shear-yield detaching resistance and the out-of-plane fluffing resistance which were based on the isotropic elastro-plastic model. When varying the misalignment of the creasing rule against the groove, the eccentricity of the crease bulging of a white-coated paperboard was compared through the experiment and simulation of the 180° folding process. Comparing the experimental deformation and the simulation, it was explained that the deviation of e contributed to making the crease deviation c_d. At the folding test, the 180° folding was compared with the experiment and simulation. The rolling pass of the folded zone was considered to intensify the deviation state. The 180° folding simulation revealed that the crease deviation of c_d ≈ 2e was assessed as an ideal condition when using the rolling pass and non-rolling pass. In the case of some shallow indentation in the experiment, 2e < c_d < 4e was observed. The inside folded corners were quite different between the simulation and experiment, especially for a certain shallow indentation model. In the simulation, the local crushing was not performed under the assumption of any isotropic properties. In the simulation, the deviation of the creased position at the 180° folding was sufficiently predictable, when compared with experimental behavior.

Ferroelectricity is demonstrated for the first time in Si(100)/SiO₂/TiN/HfO₂-ZrO₂/TiN stack using pulsed laser deposition (PLD) and the effects of temperatures, partial oxygen pressures, and thickness for the stabilization of the ferroelectric phase were mapped. Thin films deposited at a higher temperature and a higher oxygen partial pressure have a higher thickness, demonstrating a better ferroelectric response with ~12 μC/cm² remnant polarization, a leakage current of 10⁻⁷ A (at 8 V) and endurance > 10¹¹ cycles indicative of an orthorhombic crystal phase. In contrast, thin films deposited at lower temperatures and pressures does not exhibit ferroelectric behavior. These films can be attributed to having a dominant monoclinic phase, having lower grain size and increased leakage current. Finally, the effects of ZrO₂ as top and bottom layer were also investigated which showed that ZrO₂ as the top layer provided better mechanical confinement for stabilizing the orthorhombic phase instead of as the bottom layer.

In this study, orange peel waste was successfully sulfonated with SO₃-pyridine complex in 1-allyl-3-methylimidazolium chloride ionic liquid in various reaction conditions. ¹H NMR was used to verify the occurrence of the reaction and to select the most promising material for the adsorption experiments. The degree of substitution of the sulfonated orange peel waste used for cobalt and copper removal was found to be 0.82. It was prepared with the reaction temperature and time of 70 ℃ and 60 min respectively and with the SO₃-pyridine complex to-peel waste ratio of 5:1. The selected material combined with ultrafiltration removed 98% of copper and 91% of cobalt from single metal solutions and 93% of copper and 83% of cobalt from binary metal solution at pH 5 with adsorbent dosage of 12.5 mg/100 mL and initial metal concentration of 8 mg/L. Preliminary experiments were also performed with apple pomace which was sulfonated in the conditions found best for the orange peel waste. The prepared sulfonated apple pomace proved to be almost as effective in cobalt and copper removal as sulfonated orange peel waste, removing 82% of copper and 77% of cobalt from binary metal solution with 12.5 mg/100 mL dosage at pH 5 and an initial metal concentration of 8 mg/L.

To protect materials from abrasion-corrosion, various thermal spraying methods can be used to apply coatings, such as gas-flame powder spraying, plasma spraying, high velocity oxygen-fuel spraying and detonation cannon. Thermal spraying is one of the most effective methods of protecting the material from wear and corrosion, thereby increasing the service life of the material used. We present the surface modification of coatings based on Ni-Cr-Al by a pulsed plasma treatment using a plasma generator. The coatings were obtained by detonation spraying followed by pulsed plasma treatment. The changes to the structural properties of the coatings under the influence of plasma flow were studied using scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction. The mechanical and tribological properties were analyzed by surface roughness characterization, microhardness testing and tribological tests for a comprehensive analysis of changes in the characteristics of the Ni-Cr-Al coatings following pulsed plasma treatment. It was found that modification of the coating by pulsed plasma treatment causes an increase in the microhardness of the surface layer, as well as a reduction in the surface roughness and friction coefficient. According to the results of X-ray phase analysis, these improvements in the mechanical and tribomechanical properties of the obtained surfaces is associated with an increase in the content of CrNi₃, NiAl and NiCr phases in the coatings.

This study proves that lignin-based biopolymer materials can be employed as starting materials for the synthesis of novel casting binders that fulfill the current level of characteristics. The optimal concentration of the binder in the mixture was experimentally determined to be 5.8%–6.2%. It has been demonstrated in practice that the employment of ammonium salts as a technical lignosulfonate (TLS) modifier can result in the provision of cold (room temperature) curing of a mixture based on them. It was proposed to use as a technological additive that boosts the strength characteristics of a mixture of substances carboxymethyl cellulose (CMC). In a variety of adhesive materials, it is utilized as an active polymer base. The concentration limits for using CMC in the mixture are set at 0.15%–0.25%. To improve the moldability of the combination, it was suggested that kaolin clay be used as a plasticizing addition. The concentration limits for using a plasticizing additive are set at 3.5%–4.0%. The produced mixture was compared to the analog of the alpha-set method in a comparative analysis. It was discovered that the proposed composition is less expensive, more environmentally friendly, and enables the production of high-quality castings. In terms of physical, mechanical, and technological properties, the created composition of the cold curing mixture is not inferior to analogs from the alpha-set method. For the first time, a biopolymer-based binder system containing technical lignosulfonate with the addition of ammonium sulfate and carboxymethyl cellulose was used in the production of cast iron castings on the case of a cylinder casting weighing 18.3 kg from gray cast iron grade SCh20. Thus, it has been proved possible for the first time to replace phenol-based resin binders with products based on natural polymer combinations. For the first time, a cold-hardening mixture based on technological lignosulfonates has been developed without using hardeners made of very hazardous and cancer-causing hexavalent chromium compounds. But is achieved through a combination of specialized additives, including kaolin clay to ensure the mixture can be manufactured, ammonium sulfate to ensure the mixture cures, and carboxymethyl cellulose to enhance the strength properties of the binder composition. The study's importance stems from the substitution of biopolymer natural materials for costly and environmentally harmful binders based on phenolic resins. This development's execution serves as an illustration of how green technology can be used in the foundry sector. Reducing the amount of resin used in foundry manufacturing and substituting it with biopolymer binders based on technological lignosulfonates results in lower product costs as well as the preservation of the environment. Using lignin products judiciously can reduce environmental harm by using technical lignosulfonates, or compounds based on technical lignin. The combination is concentrated on