Ilushin Pavel, Vyatkin Kirill, Anton Kozlov^*

FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.5, pp. 1229-1241, 2022, DOI:10.32604/fdmp.2022.020424

Abstract When producing hydrocarbons, an important task relates to the optimization of the stock of the producing well. The main complications for wells in non-working mode are represented by the formation of asphalt-resin-paraffin deposits. This issue is one of the most common problems in the production and transportation of oil. A promising method to deal with these deposits is the application of smooth coatings made of epoxy polymers on the inner surface of the production well tubing. In this work, a number of laboratory studies were carried out on the “Cold Finger” installation to assess the effectiveness of this approach. These… More > Graphic Abstract

Xing Zhou^*

Journal of Renewable Materials, Vol.10, No.6, pp. 1623-1639, 2022, DOI:10.32604/jrm.2022.018935

Abstract A facile method, focusing on emulsification, chain extension and dispersion process in preparing waterborne polyurethane, was developed to prepare emulsion with rod-like nanoparticles. The facile method involves a water addition procedure by in situ generated water to react with polyurethane prepolymer instead of the external water addition process. As a comparison, waterborne polyurethane was synthesized through the external water addition process. According to the characterization methods including FTIR, ¹H-NMR, TEM and water swelling experiments, it is suggested there are two kinds of hydrogen bonds interactions in hard/soft domain of the novel polyurethane, and the phase separation of hard/soft domains increases… More > Graphic Abstract

Yuhao Jiang, Jialan Yao, Chengfei Zhu^*

Journal of Renewable Materials, Vol.10, No.1, pp. 135-148, 2022, DOI:10.32604/jrm.2021.016304

Abstract Poly(urea-formaldehyde) (PUF) microcapsules were prepared by in-situ polymerization with four different processes in this paper. The chemical composition, surface morphology, particle size distribution, and thermal stability were characterized by FTIR, SEM, particle size analyzer, and TGA, respectively. The results demonstrated that the agglomeration of the PUF microcapsules was related to the agglomeration of the emulsion particles caused by the changes of emulsion interface during the shell polymerization. Due to the slow deposition of the shell material, the PUF microcapsules with the core-shell structure prepared by the process with ammonium chloride as the last additive showed good dispersibility with an average… More > Graphic Abstract

Qiaoxin Zhang^1,2, Rui Chen¹, Ding Jin², Chen Zhou^2,*, Xuewu Li^3,4,5,*

Journal of Renewable Materials, Vol.9, No.1, pp. 129-144, 2021, DOI:10.32604/jrm.2021.011596

Abstract In this paper, the microstructures and rolling contact fatigue behaviors of laser cladding Inconel 625 coatings with or without post-heat treatments were analyzed. The results revealed that the fatigue resistance of the laser cladding coating after any post-heat treatment was worse than that of the as-deposited coating. First, through the finite element analysis, the distribution of stress along the thickness direction of the coating was obtained, and it was concluded that the bonding interface between the coating and the matrix had little effect on the fatigue properties of the coating. Then X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy… More >

Kamlendra Vikram¹, Uvaraja Ragavendran², Kanak Kalita^1,*, Ranjan Kumar Ghadai³, Xiao-Zhi Gao⁴

CMC-Computers, Materials & Continua, Vol.66, No.2, pp. 1771-1784, 2021, DOI:10.32604/cmc.2020.013946

Abstract In this work, diamond-like carbon (DLC) thin film coatings are deposited on silicon substrates by using plasma-enhanced chemical vapour deposition (PECVD) technique. By varying the hydrogen (H₂) flow rate, CH₄−Argon (Ar) flow rate and deposition temperature (T_d) as per a Box-Behnken experimental design (BBD), 15 DLC deposition experiments are carried out. The Young’s modulus (E) and the coefficient of friction (COF) for the DLCs are measured. By using a second-order polynomial regression approach, two metamodels are built for E and COF, that establish them as functions of H₂ flow rate, CH₄-Ar flow rate and T_d. A non-dominated sorting genetic algorithm… More >

Verónica L. Mucci¹, M. E. Victoria Hormaiztegui², Mirta I. Aranguren^1,*

Journal of Renewable Materials, Vol.8, No.6, pp. 579-601, 2020, DOI:10.32604/jrm.2020.09455

Abstract The increasing pressure from consumers and policy makers to reduce the use of synthetic polymers, whose production contributes to the depletion of non-renewable resources and are usually non- biodegradable, has prompted the efforts to find suitable bio-based sources for the production of polymers. Vegetable oils have been a frequently spotted in this search because they are versatile, highly available and a low cost liquid biosource, which can be used in the synthesis of a wide plethora of different polymers and reactive monomers. Following the same idea of reducing the environmental stress, the traditional polyurethanes that are soluble in organic solvents… More >

S. Baragetti¹, F. Tordini²

Structural Durability & Health Monitoring, Vol.3, No.3, pp. 165-176, 2007, DOI:10.3970/sdhm.2007.003.165

Abstract The effect of a TiN PVD (Physical Vapor Deposition) coating on the fatigue behaviour of the titanium alloy Ti-6Al-4V was investigated. Fatigue tests were performed on coated and uncoated, both smooth and 120° V-notched, specimens in order to evaluate the influence of the coating on the substrate fatigue resistance. Numerical analyses were carried out in order to determine the stress distributions below the specimen surface and on the coating. Several coating elastic moduli were used in such calculations. The residual stress gradient induced by the coating process deposition and the substrate plasticization were also taken into account with FEM. The… More >

F. Namavar¹, J. D. Jackson², J. G. Sharp³, S. Varma¹, H. Haider¹, C. Feschuk¹, K. L. Garvin¹

Molecular & Cellular Biomechanics, Vol.3, No.4, pp. 171-172, 2006, DOI:10.32604/mcb.2006.003.171

Abstract This article has no abstract. More >

Li Jicheng, Lin Li, Wu Di, Li Ximeng

The International Conference on Computational & Experimental Engineering and Sciences, Vol.17, No.2, pp. 43-44, 2011, DOI:10.3970/icces.2011.017.043

Abstract Two kinds of plasma sprayed Cr2O3 coating specimens are tested with electro-mechanical impedance (EMI) method. Quantitative investigation on the relationship between PZT excitation voltage and sensitivity of EMI method is performed in the frequency range of 100-110 kHz, with WK 6500B precision impedance analyzer and high excitation voltage electric impedance measurement system (HEVEIMS). A series of excitation voltage are designed from 0.01 to 15 V. Root mean square deviation (RMSD) of the PZT electric impedance signatures is used as an evaluation indicator. The results show that in the frequency range of 100-110 kHz, the RMSD values are not monotone with… More >

Jianguo Zhu, Huimin Xie, Fulong Dai

The International Conference on Computational & Experimental Engineering and Sciences, Vol.17, No.1, pp. 3-4, 2011, DOI:10.3970/icces.2011.017.003

Abstract Thermal barrier coatings (TBCs) are widely used in turbines for propulsion and power generation. During build up the coatings, the continuity of the strain at the interface results in the residual stress because of the thermal expansion misfit. Since the formation of residual stresses cannot be avoided, they have to be optimized by adaptation of the process parameters during coating manufacturing. Therefore, in order to obtain information about the characterization of residual stresses for specific process conditions, the development of residual stress measurement is of vital importance.

In this paper, several techniques on residual stress measurement are reviewed, including… More >