Powder Formation Process Research Articles

Stability of Naked Nucleic Acids under Physical Treatment and Powder Formation: Suitability for Development as Dry Powder Formulations for Inhalation.

A number of functional nucleic acids, including plasmid DNA (pDNA) and small interfering RNA (siRNA), have been attracting increasing attention as new therapeutic modalities worldwide. Dry pDNA and siRNA powder formulations for inhalation are considered practical in clinical applications for respiratory diseases. However, physical stresses in the powder-forming process may destabilize nucleic acids, particularly when vectors with stabilizing effects are not used. We herein compare the stability of naked pDNA and siRNA through various physical treatments and two powder-forming processes. The structural and functional integrities of pDNA were markedly reduced via sonication, heating, and atomization, whereas those of siRNA were preserved throughout all of the physical treatments investigated. Spray-dried and spray-freeze-dried powders of siRNA maintained their structural and functional integrities, whereas those of pDNA did not. These results demonstrate that siRNA is more suitable for powder formation in the naked state than pDNA due to its higher stability under physical treatments. Furthermore, a spray-freeze-dried powder with a high content of naked siRNA (12% of the powder) was successfully produced that preserved its structural and functional integrities, achieving high aerosol performance with a fine particle fraction of approximately 40%.

Pilot design of experiment study: effect of stirring duration and guest particle loading on electrostatic adsorption of Ti-6Al-4V composite powder formation

In recent years, materials science and engineering have increasingly focused on advanced composite powders. This study examines the preparation of micro–micro Ti-6Al-4V composite powders by electrostatic adsorption (EA). The necessity of this research lies in the demand for optimizing the Ti-6Al-4V composite powder formation process window for high-performance applications across industries. Achieving optimal EA parameters is crucial for enhancing the quality and efficiency of the powder formation process. In this study, the effect of stirring duration and guest particle loading on the EA process is investigated. The stirring time (1 to 25 min) and guest particle loading (10 to 60%) of the solution are varied to determine the ideal conditions for high adsorption efficiency. It was found that shorter stirring durations (1 min) and a lower guest particle load (10%) have a significant effect on adsorption efficiency. The results were analyzed using the DOE approach to guide future optimization of the process window. The study fills a research gap by utilizing the DOE approach to investigate stirring duration and guest particle loading, providing insights for optimizing the EA process for micro–micro Ti-6Al-4V composite powder. This approach has the potential to enhance cost-effective, durable composite powder production with broad applications in industries like aerospace and automotive. While our research currently focuses on stirring duration and guest particle loading, the application of the DOE approach lays the groundwork for future investigations into additional EA process parameters, such as pH value, particle size, and temperature to expand our understanding of efficient composite powder formation.

Metaheuristic Optimization of Powder Size Distribution in Powder Forming Process Using Multi-Particle Finite Element Method Coupled with Artificial Neural Network and Genetic Algorithm

Metaheuristic Optimization of Powder Size Distribution in Powder Forming Process Using Multi-Particle Finite Element Method Coupled with Artificial Neural Network and Genetic Algorithm

Powder Forming Process from Machined Titanium Chips via Heat Treatment in Hydrogen Atmosphere

Powder Forming Process from Machined Titanium Chips via Heat Treatment in Hydrogen Atmosphere

Production of Inhalation Phage Powders Using Spray Freeze Drying and Spray Drying Techniques for Treatment of Respiratory Infections.

The potential of aerosol phage therapy for treating lung infections has been demonstrated in animal models and clinical studies. This work compared the performance of two dry powder formation techniques, spray freeze drying (SFD) and spray drying (SD), in producing inhalable phage powders. A Pseudomonas podoviridae phage, PEV2, was incorporated into multi-component formulation systems consisting of trehalose, mannitol and L-leucine (F1 = 60:20:20 and F2 = 40:40:20). The phage titer loss after the SFD and SD processes and in vitro aerosol performance of the produced powders were assessed. A significant titer loss (~2 log) was noted for droplet generation using an ultrasonic nozzle employed in the SFD method, but the conventional two-fluid nozzle used in the SD method was less destructive for the phage (~0.75 log loss). The phage were more vulnerable during the evaporative drying process (~0.75 log further loss) compared with the freeze drying step, which caused negligible phage loss. In vitro aerosol performance showed that the SFD powders (~80% phage recovery) provided better phage protection than the SD powders (~20% phage recovery) during the aerosolization process. Despite this, higher total lung doses were obtained for the SD formulations (SD-F1 = 13.1 ± 1.7 × 10(4)pfu and SD-F2 = 11.0 ± 1.4 × 10(4)pfu) than from their counterpart SFD formulations (SFD-F1 = 8.3 ± 1.8 × 10(4)pfu and SFD-F2 = 2.1 ± 0.3 × 10(4)pfu). Overall, the SD method caused less phage reduction during the powder formation process and the resulted powders achieved better aerosol performance for PEV2.

一体成形・焼結した複層軸受の強度と摩擦摩耗特性

一体成形・焼結した複層軸受の強度と摩擦摩耗特性

S0410103 一体成形・焼結した複層軸受と対回転軸の摩擦摩耗特性

S0410103 一体成形・焼結した複層軸受と対回転軸の摩擦摩耗特性

Optimization of Process Parameters of Zirconia Reinforced Alumina by Powder Forming Process Using Response Surface Method

Powder forming process is used for fabrication of bulk ceramic components. Optimization of powder forming process parameters in the fabrication of alumina-zirconia composite used in orthopedic implants is done for desired physical property. In this research work, process parameters such as composition of zirconia, compaction pressure and sintering temperature were analyzed using Response Surface Method (RSM). The physical properties such as density, porosity and water absorption characteristics of the proposed composite were studied. To study the influence of the different process parameters over the physical properties of the fabricated composites materials, experimental runs were framed by using Box behnken method. Three factors and two levels were selected with a total of 17 runs and their consecutive tests were carried out. The validity of the model was checked and the significant parameters were identified using Analysis of variance (ANOVA). The results indicate that the sintering temperature is influencing predominantly the physical properties of composites compared to other process parameters.

Modelling of Powder Forming Processes in Transient-Dynamic Analysis of Large Plastic Deformations

In this paper, a transientdynamic analysis is presented for large deformation of powder forming process. The technique is employed using the contact friction algorithm and plasticity behavior of powder. The contact algorithm is applied by imposing the contact constraints and modifying the contact properties of frictional slip through the node-to-surface contact algorithm. A double-surface cap plasticity model is used for highly nonlinear behavior of powder. In order to predict the non-uniform density and stress distributions during powder die-pressing, the numerical schemes are examined for accuracy and efficiency in modeling of a set of powder components.

Modelling of Powder Forming Processes in Transient-Dynamic Analysis of Large Plastic Deformations

In this paper, a transientdynamic analysis is presented for large deformation of powder forming process. The technique is employed using the contact friction algorithm and plasticity behavior of powder. The contact algorithm is applied by imposing the contact constraints and modifying the contact properties of frictional slip through the node-to-surface contact algorithm. A double-surface cap plasticity model is used for highly nonlinear behavior of powder. In order to predict the non-uniform density and stress distributions during powder die-pressing, the numerical schemes are examined for accuracy and efficiency in modeling of a set of powder components.

粉末成形・焼結過程のモデリング＆シミュレーション

粉末成形・焼結過程のモデリング＆シミュレーション

Fundamentals of Ceramics Powder Forming Processes and Further Development for Novel Materials

Fundamentals of Ceramics Powder Forming Processes and Further Development for Novel Materials

粉末加工成形プロセス技術のロードマップ

粉末加工成形プロセス技術のロードマップ

Hepatitis-B Surface Antigen (HBsAg) Powder Formulation: Process and Stability Assessment

The purpose of this study was to develop a hepatitis-B surface antigen (HBsAg) dry powder vaccine formulation suitable for epidermal powder immunization (EPI) via an efficient, scalable powder-formation process. Several HBsAg dry powder formulations were prepared using four different powder-formation methods: freeze-drying/compress/grind/sieve (FD/C/G/S), spray-drying (SD), agarose beads, and spray freeze-drying (SFD). Powder properties and physical stability were determined using particle size analysis, tap density measurement, scanning electron microscopy, optical microscopy, and moisture content analysis. Physical, chemical and biochemical stability of HBsAg was determined by dynamic light scattering, an enzyme immune assay, and immunogenicity in a mouse or hairless guinea pig model. Out of the four powder-formation methods evaluated SFD outperformed other methods in the following considerations: good process efficiency, flexible scalability, and desirable particle characteristics for skin penetration. The stress posed by SFD appeared to be mild as HBsAg in the dry form retained its potency and immunogenicity. Notably, the mechanism of fast freezing by SFD actually promoted the preservation of HBsAg nanoparticle size, in good correlation with long-term biochemical stability. Among several formulations screened, the formulation containing 10 microg HBsAg in 1-mg powder with a tertiary mixture of trehalose, mannitol, and dextran, exhibited excellent overall stability performance. In conclusion, HBsAg dry powder formulations suitable for EPI were successfully prepared using SFD. Further, a systematic formulation development strategy allowed the development and optimization of an HBsAg dry powder formulation, demonstrating excellent long-term physical, biochemical, and immunological stability.

The control of nano-grain size and magnetic properties of Fe 73Si 16B 7Nb 3Cu 1 soft magnetic powder cores

Melt-spun amorphous Fe 73Si 16B 7Nb 3Cu 1 (numbers indicate at.%) alloy strip was pulverized to make flake-shaped fine powders. The powders were ball-milled to control the powder shape and to mix with polyimide-based binder of 0.5–3 wt.%, followed by cold compaction to form toroid-shaped bonded powder-metallurgical magnets. The powder cores were heat-treated to crystallize the amorphous structure and to control the nano-grain structure. Well-coated polymer binder on the powder surface decreased the coercivity and the core loss with the insulation of each powder. The analyses by differential scanning calorimetry, magnetization cores and transmission electron microscopy revealed that the best magnetic properties of powder cores was obtained after annealing for 1 h at 550–600 °C. The annealing condition to obtain the aimed grain size of 10–20 nm should be optimized considering the stored energy generated during the powder-forming process.

Reproducing Kernel Particle Method in Plasticity of Pressure-Sensitive Material with Reference to Powder Forming Process

In this paper, an application of the reproducing kernel particle method (RKPM) is presented in plasticity behavior of pressure-sensitive material. The RKPM technique is implemented in large deformation analysis of powder compaction process. The RKPM shape function and its derivatives are constructed by imposing the consistency conditions. The essential boundary conditions are enforced by the use of the penalty approach. The support of the RKPM shape function covers the same set of particles during powder compaction, hence no instability is encountered in the large deformation computation. A double-surface plasticity model is developed in numerical simulation of pressure-sensitive material. The plasticity model includes a failure surface and an elliptical cap, which closes the open space between the failure surface and hydrostatic axis. The moving cap expands in the stress space according to a specified hardening rule. The cap model is presented within the framework of large deformation RKPM analysis in order to predict the non-uniform relative density distribution during powder die pressing. Numerical computations are performed to demonstrate the applicability of the algorithm in modeling of powder forming processes and the results are compared to those obtained from finite element simulation to demonstrate the accuracy of the proposed model.

An endochronic plasticity model for finite strain deformation of powder forming processes

In this paper, the numerical modeling of powder-forming process is simulated by a finite element analysis using a density-dependent endochronic plasticity model. Endochronic constitutive model based on large strain plasticity is presented. The elastic response is stated in terms of hypoelastic model and the endochronic plasticity constitutive equations are developed in unrotated frame of reference. Constitutive equations of the endochronic theory in large strain state and their numerical integrations are established. The algorithmic modulus consistent with the numerical integration algorithm of constitutive equations is extracted. Finally, the numerical schemes are examined for efficiency in the modeling of a multi-level and tip shape powder compaction component.

Production of Nanocrystalline Sulfated Zirconia Catalysts via a Flow-Through Hydrothermal Process

ABSTRACTNanocrystalline sulfated zirconia catalysts were prepared using the rapid thermal decomposition of precursors in solution (RTDS) powder formation process. Zirconia gel formation, initial crystallization, and sulfate incorporation occurred during a brief exposure to hydrothermal conditions in the RTDS reactor. The partially crystalline zirconia solid was collected as a suspension, separated by centrifugation, and subjected to calcination to achieve full catalytic activity. Crystallinity, sulfate content, and catalytic activity of the calcined powders toward butane isomerization varied according to the hydrothermal conditions at which the zirconia powders were originally precipitated. The powders were characterized using powder XRD, FTIR, and XAS.

The grain boundary character distribution effect on the flow stress of polycrystals: The influence of crystal lattice texture

The grain size of a polycrystalline aggregate has an important effect on its properties. Several properties of materials, such as the yield and flow stresses, ductility and hardness have been suggested to show a linear dependence on (average size of grains) −1 2 . A number of models which justify the grain size effect are based on the assumption that the grains in a polycrystal have the same size and the grain boundaries the same properties. Grain boundaries are characterized by differences in their structure and, as a result, in their properties. An experimental study of the grain boundary strengthening effect in a 316L austenitic stainless steel has been carried out on a series of specimens obtained employing a powder-forming process and produced by conventional thermo-mechanical processing. The Brinell hardness was measured and analysed as a function of (grain size) −1 2 . The experimental data, in general, confirm the Hall—Petch relationship. A significant difference is observed in the values of the K H constants. This difference is discussed in terms of the influence of crystal texture on the strengthening effect of the grain boundaries.

粉体の成形シミュレーションについて

粉体の成形シミュレーションについて