powder preparation
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2021 ◽  
Vol 11 (1) ◽  
Hailin Li ◽  
Yongpeng Shen ◽  
Pu Liu ◽  
Weihua Liang ◽  
Mingjie Wang ◽  

AbstractA numerical modeling method is proposed for the melting process of Titanium metals of Titanium alloys powder preparation used for 3D printing. The melting process simulation, which involves the tight coupling between electromagnetic field, thermal field and fluid flow as well as deformation associated during the melting process, is conducted by adopting the finite element method. A two-way coupling strategy is used to include the interactions between these fields by incorporating the material properties dependent on temperature and the coupling terms. In addition, heat radiation and phase change are also considered in this paper. The arbitrary Lagrangian–Eulerian formulation is exploited to model the deformation of Titanium metal during the melting process. The distribution of electromagnetic flux density, eddy current density, temperature, and fluid flow velocity at different time can be determined by utilizing this numerical method. In a word, the method proposed in this paper provides a general way to predict the melting process of electrode induction melting gas atomization (EIGA) dynamically, and it also could be used as a reference for the design and optimization of EIGA.

2021 ◽  
Vol 1047 ◽  
pp. 103-110
Nuchanaporn Pijarn ◽  
Wisallaya Jankasemsook ◽  
Supanida Suwantha ◽  
Janpen Intaraprasert

The objective of this research was to prepare ready-to-use TiO2 and ZnO in slurry form for ready-to-use in facial foundation sunscreen. Two types of TiO2 sources were prepared as TiO2 slurry namely commercial TiO2 powder and synthesized TiO2 powder. Preparation of formula 1, 35 g solution PEG-10 dimethicone, and added 20 g solution cyclomethicone after that 45 g TiO2 powder was added slowly to the prepared substance, stirring and heated to 60-70 °C, and stir until the substance mix well. Formula 2, 46 g solution cyclomethicone added 2.5 g stearic acid and 2 g aluminum hydroxide after that stirring and heated to 60-70 °C until the substance mixed well, and TiO2 powder 49.5 g was added slowly to the continuous stirred and heated. On the other hand, ZnO slurry was prepared in the same steps. The results show that formula 1was the best formulation. Due to it was not precipitation and good compatibility with an emulsifier, therefore, formula 1was chosen to study in various volumes. The texture and stability of the prepared slurry were similar to the commercial slurry. Two sunscreen formulas were differently formulated by containing prepared and commercial slurry and evaluated. There were no significant differences in results between prepared slurry and commercial slurry. To investigate the satisfaction of products, 30 volunteers were asked to use products for one week and answer the questionnaires. The product containing prepared slurry was satisfied by 93.33% of volunteers, whereas the product containing commercial slurry was satisfied by 76.66% of volunteers.

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1044
Marcin Winnicki

Based on the recent analysis of various databases, cold spray (CS), the newest method among thermal spraying technologies, has received the unabated attention of hundreds of researchers continuously since its invention in the 1980s. The significance of CS lies in the low process temperature, which usually ensures compressive residual stresses and allows for the formation of coatings on a thermally sensitive substrate. This paper concerns the low-pressure cold spray (LPCS) variant employed for forming metal matrix composites (MMCs) with high ceramic contents and all-ceramic coatings. At the very beginning, the influence of LPCS process parameters on deposition efficiency (DE) is analysed. In the next part, the most useful feedstock powder preparation techniques for LCPS are presented. Due to the combination of bottom-up powder production methods (e.g., sol-gel (SG)) with LCPS, the metal matrix that works as a binder for ceramic particles in MMC coatings can be removed, resulting in all-ceramic coatings. Furthermore, with optimization of spraying parameters, it is possible to predict and control phase transformation in the feedstock material. Further in the paper, differences in the bonding mechanism of metal–ceramic mixtures and ceramic particles are presented. The properties and applications of various MMC and ceramic coatings are also discussed. Finally, the exemplary direction of CS development is suggested.

Pharmaceutics ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1162
Wei Yan ◽  
Ruide He ◽  
Xiaojiao Tang ◽  
Bin Tian ◽  
Yannan Liu ◽  

The feasibility of using respirable bacteriophage (phage) powder to treat lung infections has been demonstrated in animal models and clinical studies. This work investigated the influence of formulation compositions and excipient concentrations on the aerosol performance and storage stability of phage powder. An anti-Acinetobacter baumannii phage vB_AbaM-IME-AB406 was incorporated into dry powders consisting of trehalose, mannitol and L-leucine for the first time. The phage stability upon the spray-drying process, room temperature storage and powder dispersion under different humidity conditions were assessed. In general, powders prepared with higher mannitol content (40% of the total solids) showed a lower degree of particle merging and no sense of stickiness during sample handling. These formulations also provided better storage stability of phage with no further titer loss after 1 month and <1 log titer loss in 6 months at high excipient concentration. Mannitol improved the dispersibility of phage powders, but the in vitro lung dose dropped sharply after exposure to high-humidity condition (65% RH) for formulations with 20% mannitol. While previously collected knowledge on phage powder preparation could be largely extended to formulate A. baumannii phage into inhalable dry powders, the environmental humidity may have great impacts on the stability and dispersion of phage; therefore, specific attention is required when optimizing phage powder formulations for global distribution.

2021 ◽  
Vol 15 (1) ◽  
pp. 15-25
Nahar Cahyandaru

Andesite rock is commonly used as a heritage building in Southeast Asia, especially in Indonesia. However, the study on consolidation of andesite rock is still limited. This study aimed to evaluate the application effectiveness of TEOS-based material on the andesite type rock in heritage materials. TEOS was used as a modular system with andesite powder to form mortar. This andesite-TEOS mortar system was applied to conservation techniques, especially for gap and joint filling.   TEOS modular system was successfully applied to the andesite type rock, resulting in chemical and physical properties. The color of the mortar and the compatibility with the original rock color were designed from the rock powder preparation. The excellent repair was obtained by a combination of dot technique gluing using epoxy resin and the TEOS mortar application in the gaps. Furthermore, this technique was successfully applied to the big Buddha Statue Head andesite rock for the emergency intervention of the falling fragment. Keyword: Andesite, Consolidation, TEOS, Mortar  

2021 ◽  
Jingyi Guan ◽  
Daxin Li ◽  
Zhihua Yang ◽  
Bingzhu Wang ◽  
Delong Cai ◽  

Abstract Dense (Ta, Nb, Hf, Zr, Ti)(BCN) ceramics (HEC-2) were successfully synthesized via hot-pressing sintering. Results show that sintering temperature and (BCN) addition have great impacts on the microstructure and mechanical properties of HEC-2 ceramics. The microstructure and phase of HEC-2 bulk ceramics were characterized by SEM, XRD and TEM. It was found that high-entropy phase, oxide phase and BN/C phase were precipitated when HEC-2119 powders were sintered at 1900 oC. In addition, the Vicker’s hardness, Bending strength, Bulk density and Open porosity of HEC-2319 ceramic are 24.54 GPa, 522.00 MPa, 9.07 g/cm3 and 0.05%, respectively, whose molar ratio of metal to (BCN) is 1: 0.334. In this work, BCN high-entropy ceramics were sintered on the basis of powder preparation, as provided that sintering temperatures and components have great influences on microstructure and mechanical properties of HEC-2 ceramics.

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