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The coalescence, the initial stage of sintering, of two contacted Cu nanoparticles is investigated under different heating rates of 700, 350 and 233 K/ns. The nanoparticles coalesced rapidly at the initial stage when the temperature of the system is low. Then, the nanoparticles collided softly in an equilibrium period. After the system was increased to a high temperature, the shrinkage ratio, gyration radius and atoms’ diffusion started to change dramatically. The lower heating rate can result in smaller shrinkage ratio, larger gyration radius and diffusion of atoms. However, the growth of sintering neck is hardly influenced by the heating rate. The results provide a theoretical guidance for the fundamental understanding and potential application regarding nanoparticle sintering.

This paper studies the effects of heating rate 4 × 10${}^{11}$ K/s, 4 × 10${}^{12}$ K/s, 4 × 10${}^{13}$ K/s; impurity concentration of Cu on Ni${}_{1-x}$Cu${}_x$ bulk with x = 0.1, x = 0.3, x = 0.5, x = 0.7; atom number (N), N = 4000 atoms, 5324 atoms, 6912 atoms, 8788 atoms at temperatures (T), T = 300 K; N = 6912 atoms at T = 300 K, 400 K, 500 K, 600 K, 700 K, 800 K; N = 6912 atoms at T = 600 K after time annealing temperature (t), t = 500 ps on the structure, crystallization temperature and crystallization process of Ni${}_{1-x}$Cu${}_x$ bulk by molecular dynamics (MD) method with interactive embedding Sutton–Chen (ST) and periodic boundary conditions. The structural characteristics were analyzed through radial distribution function (RDF), energy total (E${}_{\mathrm{\text{tot}}}$), size (l) and common neighborhood analysis (CNA) method; temperature (T), crystallization temperature (T${}_g$), crystallization process through relationship between E${}_{\mathrm{\text{tot}}}$, T. The results showed Ni${}_{1-x}$Cu${}_x$ bulk and links Ni–Ni, Ni–Cu, Cu–Cu always exist in 03 types structures: FCC, HCP, Amor. When time annealing temperature increases then Ni${}_{1-x}$Cu${}_x$ bulk moves from a crystalline state to an amorphous state. When increases impurity concentration of Cu in Ni${}_{1-x}$Cu${}_x$ bulk, then the structure unit number FCC, HCP decreases and then increases, structure unit number Amor increases and then decreases. When atom number (N) increases, decreasing T and increasing time annealing temperature lead to structure unit number FCC, HCP increases, Amor decreases and structural, crystallization temperature, crystallization process of Ni${}_{1-x}$Cu${}_x$ bulk change.

While thermoplastic polymers exhibit several desirable properties, their applicability is limited by their high viscosity and extreme processing conditions. To overcome these limitations, in this study, we used the thermoforming process to produce carbon fiber/polyetherketoneketone (CF/PEKK) laminates, which were pre-made through an oven-based consolidation process using prepregs. The laminates were produced at three different heating rates ($40^{\circ }$C/min, $75^{\circ }$C/min and $100^{\circ }$C/min). The laminates produced at the heating rate of $40^{\circ }$C/min showed improved interlaminar shear strength, $90^{\circ }$ tensile strength, and average interlaminar fracture toughness. On the other hand, heating at rates higher than $40^{\circ }$C/min increased the initiation value of the interlaminar fracture toughness ($G_{\mathrm{\text{IC}}-\mathrm{\text{I}}})$ but resulted in nonuniform composites of poor quality. This is because increasing the heating rate reduced the uniformity of the heat distribution with the laminates, resulting in the polymer molecules exhibiting different binding rates and thus nonuniform cross-linking. Thus, the proposed method is a suitable one for producing high-quality thermoplastic composites.

The sensitivity of a temperature-compensating fiber Bragg grating (FBG) sensor which has different FBGs in one fiber line was analyzed for the real time measurement of mechanical normal strain in structures. Measurement of mechanical strains of the aluminum beam surface by the double FBG sensor was performed under various heating rates and temperature range. The results were compared with those of an electrical resistance strain gage. A considerable delay in the strain measurement by the double FBG sensor during the heating process was shown, which could be quantified for the strain compensation by the introduction of a strain retardation factor to the FBG sensor.

This paper investigates the effects of interparticle distance and heating rate on the aggregation characteristics of Cu/Au nanoparticles using molecular dynamics (MD) simulations, and focuses on discussing the effects of the two above-mentioned factors on the entire system. Our results suggested that the reduction in heating rate and increasing the initial distance of the particles would both contribute to raising the initial sintering temperature. However, when the particles’ initial distance was greater than the cut-off radius of the system, the initial sintering temperature was not increased any longer, but fluctuated within a certain range. Furthermore, the sintering force of the nanoparticles at the initial sintering temperature was investigated, and it was found that the heating rate made no obvious difference to it. Nonetheless, the sintering force varied under different initial distance of the particles (at the same heating rate) due to system energy changes.

Sediment quality strongly depends on organic matter conditions in the sediment, thus identifying organic matter conditions in sediment is very necessary. The thermal analysis (TG/DTA) is widely used to understand the ignition characteristic of sediment. It has been reported that different types of organic matter have different exoergic temperatures. Unfortunately, no any TG/DTA analysis standard has been proposed for sediment analysis. In other words, TG/DTA analysis of sediment is different from a study to another study. This study is aiming at proposal of TG/DTA analysis for identifying organic matter conditions in sediment. Different sediments collected from different littoral regions in Japan were used in the TG/DTA analysis. The sediments were first oven dried, and then were passed through 75-μm sieve. The sediments with and without passing through 75-μm sieve were used in the analysis. In the analysis, different weights (10 to 30 mg) of samples were ignited from 25 to 850°C with heating rates of 1, 5, 10, and 20°C /min. It was observed that a more accurate analysis could be obtained when the sediment less than 75-μm was used, specifically for the sediment collected from the littoral region exposed to wastewater discharge. The exothermic peak easily appeared with increasing weight of the sample, which easily identified organic matter conditions in the sediment. Moreover, mass loss on ignition of the sediment burned at ≤5°C /min was higher than that at ≥10°C /min. This ensured that organic matter was incompletely burned at≥10°C /min. It can be concluded from our results that 20-30 mg of sediment passed through 75-μm sieve should be burned at 5°C /min to obtain a more accurate analysis of organic matter conditions in sediment.