Effect of nanobubbles on powder morphology in the spray drying process.

This study investigated the influence of gas-injected nanobubbles on the morphology of particles during spray drying under various experimental conditions. The nanoparticle tracking system was used to measure the generation, size, and concentration of nanobubbles. Experiments were conducted at different temperatures (160°C-260°C) and feed rates (0.2-0.26 g/s) to examine the effect of nanobubbles on spray drying and present diverse results. The deionized (DI) water with generated nanobubbles had a particle concentration of 1.8 × 108 particles/mL and a mean particle size of 242.6 nm, which was ∼3.31 × 107 particles/mL higher untreated DI water. The maltodextrin solution containing nanobubbles also showed a significant increase in particle generation, with a concentration of 1.62 × 109 particles/mL. The viscosity of the maltodextrin solution containing nanobubbles decreased by ∼18%, from 9.3 mPa·s to 7.5 mPa·s. Overall, the size of the generated particles was similar regardless of nanobubble treatment, but there was a tendency for particle size to increase under specific temperature (260°C) and feed flow rate (0.32 g/s) conditions. Furthermore, it was observed that the Hausner ratio significantly varied with increasing temperature and feed flow rate, and these results were explained through scanning electron microscopy images. These findings confirm that the gas nanobubbles mixed in the feed can exert diverse effects on the spray drying system and powder characteristics depending on the operating conditions. This study suggests that nanobubbles can contribute to a more efficient process in spray drying and can influence the morphological characteristics of particles depending on the spray drying conditions.

Physicochemical and bioactive constituents, microbial counts, and color components of spray-dried Syzygium cumini L. pulp powder stored in different packaging materials under two controlled environmental conditions.

Currently, the demand for functional food items that impart health benefits has been rising. Blackberry (Syzygium cumini L.) fruit has high anthocyanin content and other functional attributes. However, this seasonal fruit is highly perishable, and a large proportion of it goes unharvested and wasted worldwide. Spray drying of the fruit pulp can impart improved shelf life, ensuring long-term availability for consumers to exploit its health benefits. The storage quality varies according to the type of packaging material and the storage environment. Therefore, in this study, the shelf life span of the spray-dried Syzygium cumini L. pulp powder (SSCPP) was investigated during 6 months of storage under three types of packaging materials (i.e., polystyrene, metalized polyester, and 4-ply laminates) in a low-temperature environmental (LTE) and at ambient environmental conditions. The physicochemical stability of bioactive principles (TPC and TAC), microbial counts, and color components were analyzed at 0, 2, 4, and 6 months of storage. There was a significant gradual loss of dispersibility and solubility with an increase in flowability, bulk density, and wettability during the entire storage period for all three packaging materials. The TSS, pH, TPC, TAC, and microbial counts decreased in the SSCPP both at ambient and LTE conditions during the study. Among all the packaging materials, the 4-ply laminate was found to be the most appropriate and safe for storage of spray-dried SCPP at LTE conditions.

Optimization of spray drying process of Japanese apricot (Prunus mume Sieb. et Zucc.) juice powder using nondigestible maltodextrin by response surface methodology (RSM).

The optimal spray-drying conditions for manufacturing Japanese apricot (Prunus mume Sieb. et Zucc.) juice powder (JAJP) using response surface methodology (RSM) were investigated. The optimization was performed using two independent factors, which are inlet air temperature (130-180 °C) and different concentrations of nondigestible maltodextrin (NMD) as a carrier agent (10-30%). Responses such as drying yield, moisture content, water solubility index (WSI), bulk density, color, pH, and antioxidant activities of JAJP were investigated. Moisture content, vitamin C content, color, antioxidant activity, pH and bulk density were greatly influenced by inlet air temperature, but dry yield and WSI were only significantly affected by NMD concentration. The optimum spray drying conditions were determined as 14.7% NMD concentration and 154.5 °C inlet air temperature, respectively. At these optimum conditions, a drying yield of 55.73%, 4.84% moisture content, 90.98% WSI, 0.59 g/mL of bulk density, and 169.87 mg/g vitamin C content in JAJP were measured. Therefore, JAJP with the desirable physicochemical properties could be produced.

Production of encapsulated (25R)-Spirost-5-en-3ß-ol powder with composite coating material and its characterization.

The potential of the (25R)-Spirost-5-en-3ß-ol (diosgenin) is underutilized due to its astringent mouthfeel and aftertaste. To make the consumption more, this research rivets over the use of suitable techniques for encapsulating the diosgenin to use its health benefits for preventing the health disorders. The (25R)-Spirost-5-en-3ß-ol(diosgenin) is gaining popularity in the food market by proving its potential health benefits. This study rivets over the encapsulation of diosgenin due to its high bitter taste which restricts its incorporation in functional foods. Maltodextrin and whey protein concentrates were used as the carrier for encapsulating diosgenin at varying concentrations from 0.1 to 0.5 % and evaluated for powder properties. The optimal conditions were obtained based on the most suited data ranged from the selected properties for the powder. The spray dried 0.3% diosgenin powder produced most suitable properties for powder recovery, encapsulation efficiency, moisture content, water activity, hygroscopicity, and particle size as 51.69-72.18%, 54.51-83.46%, 1.86-3.73%, 0.38-0.51, 10.55-14.08% and 40.38-88.02 µm respectively. The significance of this study relies on the more and better utilization of the fenugreek diosgenin in edible form by masking the bitterness. After encapsulation the spray dried diosgenin is more accessible in powder format with edible maltodextrin and whey protein concentrate. The spray dried diosgenin powder could be a potential agent that fulfils nutritional demands along with protection from some chronic health perturb.

Genistein microparticles prepared by antisolvent recrystallization with low-speed homogenization process.

To create genistein particles, a brand-new antisolvent recrystallization technique was employed. The response surface approach was utilized to optimize the single factor test findings, which were acquired via the preliminary tests. The ideal liquid-to-liquid ratio was 9, the solution concentration was 21 mg/mL, the nozzle diameter was 700 µm, the feed rate was 39.65 mL/min, and the homogenization rate was 1500 rpm. The smallest mean particle size measured was 202.782 nm. SEM was used to study the powder's morphology, while thermal analysis and infrared imaging were used to evaluate its characteristics. The homogeneous antisolvent recrystallization method-prepared GMP has a better dissolving rate and stronger antioxidant activity when compared to genistein powder. The antisolvent recrystallization approach used in this study, which uses low-speed homogenizing instead of conventional grinding and homogenizing, can successfully reduce particle size, improve bioavailability, and use less energy. This topic may thus be made popular because it has real-world applications.

Process optimization of physicochemical properties of spray-dried Hydrocotyle umbellata L. extract

Abstract Hydrocotyle umbellata L., Araliaceae, is a species that is recommended in Ayurvedic medicine for its effects on the central nervous system, such as anxiolytic and memory-stimulant effects. Despite the medicinal potential of this species, its phytopharmaceutical and technological potential to produce standardized extracts has not been investigated. This study analyzes the influence of spray drying parameters on the contents of the chemical markers (total phenolic, total flavonoid, and hibalactone) and the functional properties of H. umbellata extract. The optimization of drying conditions was performed using a central composite design combined with response surface methodology and desirability function approach. The mathematical models fitted to experimental data indicated that all the evaluated drying parameters significantly influenced the chemical contents. The optimal conditions were: inlet temperature of 120 °C, feed flow rate of 4 mL min-1, and colloidal silicon dioxide:maltodextrin ratio of 16%:4%. Under these conditions, the powder samples had spherical particles and desirable physicochemical and functional properties, such as low water activity and moisture content, good product recovery, reconstitution, and flowability. Thus, spray drying might be a promising technique for processing standardized H. umbellata extracts.

Compaction Properties of Particulate Proteins in Binary Powder Mixtures with Common Excipients.

The increasing interest in protein- and peptide-based oral pharmaceuticals has culminated in the first protein-based products for oral delivery becoming commercially available. This study investigates the compaction properties of proteins in binary mixtures with common excipients up to 30% (w/w) of particulate protein. Two model proteins, lysozyme and bovine serum albumin, were compacted with either microcrystalline cellulose, spray-dried lactose monohydrate, or calcium hydrogen phosphate dihydrate at two different compaction pressures. Compared to the compacted pure materials, a significant increase in the tensile strength of the compacts was observed for the binary blends containing lysozyme together with the brittle excipients. This could be attributed to the increased bonding forces between the particles in the blend compared to the pure materials. The use of bovine serum albumin with a larger particle size resulted in a decrease in tensile strength for all the compacts. The change in the tensile strength with an increasing protein content was non-linear for both proteins. This work highlights the importance of considering the particulate properties of protein powders and that protein-based compacts can be designed with similar principles as small-molecules in terms of their mechanical tablet properties.

Enabling the drug combination of celecoxib through a spherical co-agglomeration strategy with controllable and stable drug content and good powder properties.

Combining celecoxib with other chemopreventive drugs is a promising method of chemoprevention for cancer, especially for colorectal cancer. However, the traditional drug combination approaches are restricted with high-cost apparatus, complex and numerous unit operations. This work aims to develop an efficient spherical co-agglomeration strategy for celecoxib in combination with lovastatin, which can achieve drug combination in a single crystallization unit. The ternary solvent system was determined based on molecular simulation, and then a stable spherical agglomeration process was developed through the design of molar fraction of anti-solvent (MFA) and stirring rate to produce spherical agglomerates with high sphericity (84.2-89.9 %) and narrow size distribution. On this basis, celecoxib-benzoic acid spherical co-agglomerates were designed to form a complete spherical co-agglomeration strategy, which includes solvent system selection, spherical agglomeration and spherical co-agglomeration. Finally, celecoxib-lovastatin spherical co-agglomerates with synergistic efficacy were successfully produced by this strategy, with controllable and stable drug content (fluctuation < 2.7 %), good powder properties, and improved tabletability.

[Distribution of surface components in spray-dried powder of binary system of berberine hydrochloride and dextran based on hydrodynamic size].

The present study explored the correlation between the hydrodynamic size(i.e., hydrated particle size) and the surface component distribution of spray-dried powder based on the binary system model of berberine hydrochloride and dextran. A variety of mixture solutions containing substances of different proportions were prepared, and the hydrated particle sizes of the solutions were measured by laser light scattering technique. Then the effects of molecular weight and mixing proportion on the particle size were analyzed. After the solutions were spray-dried, the surface components of spray-dried powder were determined by X-ray photoelectron spectroscopy. The changes of hydrated particle size of the two substances in different solutions were measured with the altered solution environments, and the distribution of surface components after spray-drying was observed. The results of particle size measurement showed that different solution environments would change the hydrodynamic size of substances. Specifically, the particle size of berberine hydrochloride increased with the increase in ionic strength and solution pH, while the particle size of dextran decreased with the increase in ionic strength and increased with the increase in solution pH. The results of surface components of the spray-dried powder indicated that berberine hydrochloride was prone to accumulate on the surface of particles during spray-drying because of its large hydrodynamic size. Therefore, hydrodynamic size is considered an important factor affecting the surface component distribution of spray-dried powder. As revealed by scanning electron microscopy of the particle morphology of spray-dried powder, the particles of berberine hydrochloride spray-dried powder were irregularly elliptic, and the particles of dextran and mixture spray-dried powders were irregularly spherical with the shrunken surface. Finally, the FT4 powder rheometer and DVS instrument were used to determine the stability, adhesion, and hygroscopicity of the powder. The results showed that when berberine hydrochloride was enriched on the surface, the adhesion of the mixture increased and the fluidity became worse, but the hygroscopicity was improved to a certain extent. In addition, as found by hygroscopic kinetic curve fitting of spray-dried powder, the hygroscopic behaviors of all spray-dried powder conformed to the double exponential function.

Dry Powder Inhalers Based on Chitosan-Mannitol Binary Carriers: Effect of the Powder Properties on the Aerosolization Performance.

Carriers play an important role in improving the aerosolization performance of dry powder inhalers (DPIs). Despite that intensive attention had been paid to the establishment of the advanced carriers with controllable physicochemical properties in recent years, the design and optimization of carrier-based DPIs remain an empiricism-based process. DPIs are a powder system of complex multiphase, and thus their physicochemical properties cannot fully explain the powder behavior. A comprehensive exposition of powder properties is demanded to build a bridge between the physicochemical properties of carriers and the aerosolization performance of DPIs. In this study, an FT-4 powder rheometer was employed to explore the powder properties, including dynamic flow energy, aeration, and permeability of the chitosan-mannitol binary carriers (CMBCs). CMBCs were self-designed as an advanced carrier with controllable surface roughness to obtain enhanced aerosolization performance. The specific mechanism of CMBCs to enhance the aerosolization performance of DPIs was elaborated based on the theory of pulmonary delivery processes by introducing powder properties. The results exhibited that CMBCs with appropriate surface roughness had lower special energy, lower aeration energy, and higher permeability. It could be predicted that CMBC-based DPIs had greater tendency to fluidize and disperse in airflow, and the lower adhesion force between particles enabled drugs to be detached from the carrier to achieve higher fine particle fractions. The specific mechanism on how physicochemical properties influenced the aerosolization performance during the pulmonary delivery processes could be figured out with the introduction of powder properties.

[Prediction of formability of flavonoid extract granules by dry granulation based on design space and RBFNN].

In this paper, a flavonoid extract powder properties-process parameters-granule forming rate prediction model was constructed based on design space and radial basis function neural network(RBFNN) to predict the formability of flavonoid extract gra-nules. Box-Behnken experimental design was employed to explore the mathematical relationships between critical process parameters and quality attributes. The design space of critical process parameters was developed, and the accuracy of the design space was verified by Monte Carlo method(MC). Design Expert 10 was used for Box-Behnken design and mixture design. Scutellariae Radix mixed powder was prepared and its powder properties were measured. The mixed powder was then subjected to dry granulation and the granule forming rate was determined. The correlations between powder properties were analyzed by variance influence factor(VIF), and principal component analysis(PCA) was performed for the factors with strong collinearity. In this way, a prediction model of powder properties-process parameters-granule forming rate was established based on RBFNN, the accuracy of which was evaluated with examples. The results showed that the model had a good predictive effect on the granule forming rate, with the average relative error of 1.04%. The predicted value and the measured value had a high degree of fitting, which indicated that model presented a good prediction ability. The prediction model established in this study can provide reference for the establishment of quality control methods for Chinese medicinal preparations with similar physical properties.

Naringenin Ultrafine Powder Was Prepared by a New Anti-Solvent Recrystallization Method.

Raw naringenin directly isolated from plants is significantly limited by its poor dissolution rate and low bioavailability for clinical and in vivo studies. This study reported a method for the preparation of naringenin ultrafine powder (NUP) using a novel anti-solvent recrystallization process; preliminary experiments were conducted using six single-factor experiments. The response surface Box-Behnken (BBD) design was used to optimize the level of factors. The optimal preparation conditions of the DMP were obtained as follows: the feed rate was 40.82 mL/min, the solution concentration was 20.63 mg/mL, and the surfactant ratio was 0.62%. The minimum average particle size was 305.58 ± 0.37 nm in the derived optimum conditions. A scanning electron microscope was used to compare and analyze the appearance and morphology of the powder before and after preparation. The characterization results of FTIR, TG and XRD showed that no chemical change occurred in the powder before and after preparation. Through the simulated gastrointestinal juice digestion experiment, it was confirmed that the absorption rate of NUP was 2.96 times and 4.05 times higher than raw naringenin, respectively. Therefore, the results showed that the reduction in the particle size through the use of low-speed recrystallization could improve the absorption rate and provided a feasible approach for the further applications.

Control of Drug-Excipient Particle Attributes with Droplet Microfluidic-based Extractive Solidification Enables Improved Powder Rheology.

PURPOSE: Industrial implementation of continuous oral solid dosage form manufacturing has been impeded by the poor powder flow properties of many active pharmaceutical ingredients (APIs). Microfluidic droplet-based particle synthesis is an emerging particle engineering technique that enables the production of neat or composite microparticles with precise control over key attributes that affect powder flowability, such as particle size distribution, particle morphology, composition, and the API's polymorphic form. However, the powder properties of these microparticles have not been well-studied due to the limited mass throughputs of available platforms. In this work, we produce spherical API and API-composite microparticles at high mass throughputs, enabling characterization and comparison of the bulk powder flow properties of these materials and greater understanding of how particle-scale attributes correlate with powder rheology. METHODS: A multi-channel emulsification device and an extractive droplet-based method are harnessed to synthesize spherical API and API-excipient particles of artemether. As-received API and API crystallized in the absence of droplet confinement are used as control cases. Particle attributes are characterized for each material and correlated with a comprehensive series of powder rheology tests. RESULTS: The droplet-based processed artemether particles are observed to be more flowable, less cohesive, and less compressible than conventionally synthesized artemether powder. Co-processing the API with polycaprolactone to produce composite microparticles reduces the friction of the powder on stainless steel, a common equipment material. CONCLUSIONS: Droplet-based extractive solidification is an attractive particle engineering technique for improving powder processing and may aid in the implementation of continuous solid dosage form manufacturing.

On the Importance of Secondary Component Properties for Cold Spray Metallization of Carbon Fiber Reinforced Polymers.

In previous studies at McGill University, tin was successfully cold sprayed onto carbon fiber reinforced polymers (CFRPs). A "crack-filling" mechanism was described as the deposition mechanism that allowed deposition of tin onto the CFRP. Improving the coating conductivity for lightning strike protection (LSP) purposes was explored by adding other metal powders (aluminum, copper, zinc) to tin and cold spraying on the CFRP. At the same time, it was noticed that the addition of this secondary component (SC) provided an increase in deposition efficiency (DE); tamping was initially hypothesized to explain this improvement, thus prompting a study solely on the effect of SC hardness. However, it is recognized that other powder characteristics may also be influencing the DE. Thus, in this study, SCs with a wider variety of particle sizes, morphologies, densities and hardness values were mixed with tin and sprayed on CFRPs. The effect of SC properties on tin deposition is discussed and, while SC particle size, morphology and density individually do not notably influence the DE, the impact energy of the SC does. This opens a discussion on optimal parameters for deposition of metals on CFRP, based on results and observations from the literature.

Microencapsulation of steroidal saponins from agave sap concentrate using different carriers in spray drying.

Concentrated agave sap is a product with in vivo proven hypocholesterolemic and hypoglycemic activities, as well as in vitro anticancer potential. In the present work, a factorial design was used to determine the suitable drying conditions of concentrated agave by studying the effect of inlet temperature (150 °C, 180 °C and 210 °C) and the type of carrier agent (maltodextrin, hydroxypropyl methylcellulose, guar gum and xanthan gum). The response variables for each treatment were the product recovery and microencapsulated saponins. Further characterization of concentrated agave powders was performed: solubility in water, hygroscopicity, moisture content, tap density, bulk density, Carr's index followability and morphology by scanning electron microscopy analysis. The hydroxypropyl methylcellulose proved to improve physicochemical properties and enhance product yield, using 210 °C inlet temperature and a mix of carrier agents of maltodextrin/hydroxypropyl methylcellulose/xanthan gum at 50/48.5/1.5 (w/w/w) proportion exhibited the highest saponin recovery of 53.81%. Moreover, different carrier agents in powders revealed two shapes, regular spherical shape with smooth surface and collapsed shapes. The use of polymers excipients helped to decrease the stickiness of the desired product and enhanced the powder stability and microencapsulation of the steroidal saponins.

[Application of design technology for preparing Lingzhu Powder particles based on solvent evaporation method].

Targeting the deficiencies of Lingzhu Powder, this study introduced the particle design technology to improve its quality. Based on the mechanism of particle design for powder and the characteristics of solvent evaporation method, composite particles consisting of Succinum, Cinnabaris, and artificial Bovis Calculus were prepared. And the powder properties of composite particles and physical mixtures as well as the content uniformity of toxic components were investigated for exploring the technological advantages of particle design in improving the quality of Lingzhu Powder. The results showed that the composite particles prepared using solvent evaporation method and particle design technology were micro-particles, and the stable agglomerate structure could be observed under SEM. Composite particles exhibited better fluidity and compliance in oral intake than physical mixtures. The differences in chromatism, bulk density, and content uniformity of the composite particles were smaller than those of physical mixtures, and the corresponding RSD values \[4.8%, 1.8%, 3.4%(bilirubin), and 0.63%(HgS), respectively\] were smaller. The solvent evaporation combined with particle design technology can be utilized to significantly improve the quality of Lingzhu Powder, which has provided new ideas for the optimization of the quality of traditional Chinese medicinal powder.

[Particle design for improving taste and homogeneity of traditional Chinese medicinal powder: taking Zhuhuang Chuihou Powder as an example].

Due to the complex source and different physical and chemical properties of traditional Chinese medicines(TCM) powder, there are many common pharmaceutical problems in its preparation, such as large particle size difference, poor mixing uniformity, and poor compliance with oral intake, which has directly affected the quality of solid preparations as well as their clinical efficacy and safety. This study observed the property of Zhuhuang Chuihou Powder and extract its pharmaceutical defects. It was found that realgar and calcined Borax in Zhuhuang Chuihou Powder were heavy in texture and toxic, and they were easy to be isolated, indicating the potential safety hazard. At the same time, Coptidis Rhizoma and Phellodendri Chinensis Cortex were the main sources of its bitterness. Therefore, based on the idea of "drug-excipients unity", the particle design technology was used to prepare core/shell-type composite particles with bitter medicines as the core and mineral medicines as shell. Both infrared spectroscopy and scanning electron microscopy results indicated the formation of composite particles, and the taste of these composite particles were improved. Compared with the physical mixtures, the composite particles exhibited significantly decreased RSD values in the content uniformity of berberine hydrochloride, arsenic disulfide, and sodium tetraborate and appearance uniformity. The introduction of particle design technology solved the problem of uneven dispersion of Zhuhuang Chuihou Powder, thus ensuring its uniform dispersion, stability, and control and improving the quality of the original preparation. This has provided a scientific basis for the quality control of TCM powder.

[Powder modificationfor improving content uniformity of Ziyin Yiwei Capsules].

Based on the defects in powder properties of the contents of Ziyin Yiwei Capsules, this study screened out the main medicinal slice powders causing the poor powdery properties, and introduced the powder modification process to improve the powdery properties of these slice powders, the pharmaceutical properties of the capsule contents, and the content uniformity of Ziyin Yiwei Capsules, so as to provide a demonstration for the application of powder modification technology to the preparation of Chinese medicinal solid preparations. Through the investigation on the powder properties of the contents of Ziyin Yiwei Capsules, it was clarified that the pulverized particle size of the capsule contents had a good correlation with the pulverization time. According to the measurement results of the powder fluidity and wettability, the quality defects of the capsule contents were caused by the fine powders of Taraxaci Herba and Lungwortlike Herba. "Core-shell" composite particles were prepared from medicinal excipients magnesium stearate and fine powders of Taraxaci Herba and Lungwortlike Herba slices after ultra-fine pulverization to improve the powder properties of the problematic fine powders. Powder characterization data including fluidity and wettability were measured, followed by scanning electron microscopy(SEM) and infrared ray(IR) detection. It was determined that the optimal dosage of magnesium stearate was 2%, and the compositing time was 3 min. The composite particles were then used as content components of the Ziyin Yiwei Capsules. The powder characteristics between the original capsule and the modified composite capsule including the particle size, fluidity, wettability, uniformity of bulk density, and uniformity of chromatism as well as the content uniformity and in vitro dissolution were compared. The results showed that the powder characteristics and content uniformity of the prepared composite capsule were significantly improved, while the material basis of the preparation was not changed before and after modification. The preparation process was proved to be stable and feasible. The powder modification technology solved the pharmaceutical defects that were easy to appear in the preparation of traditional capsules, which has provided experimental evidence for the use of powder modification technology for improving the quality of Chinese medicinal solid preparations and promoting the secondary development and upgrading of traditional Chinese medicinal dosage forms such as capsules.

Physicochemical, reconstitution, and morphological properties of red pepper juice (Capsicum annuum L.) powder.

ABSTRACT: The aim of this study is to investigate the influence of the encapsulating agents (maltodextrin (MD), whey protein isolate (WP), and gum arabic (GA)) and their blends (MD + WP, MD + GA, WP + GA, and MD + WP + GA) on the powder yield, drying ratio, productivity, drying rate, physicochemical, bulk, reconstitution, and morphological properties of the red pepper juice powders (RPJP) and to calculate the energy efficiency of the spray dryer. A pilot-scale spray dryer (180/80 °C inlet/outlet air temperature, 392 kPa atomization pressure, 1.54 m3/min air flow rate, and a 12.0 ± 0.2°Bx feeding concentration) was used for the drying experiments. The acceptable powder yield (52.48-94.25%) and specific energy consumption values (7.39-9.72 MJ/kg H2O) were obtained. The RPJP presented moisture content and water activity values lower than 10% and 0.367. The red pepper juice powders were found to be highly dispersible (88.34-95.18%), soluble (solubility time and index are 9.75-77.25 s and around 99%), and easly wetted (9.75-122.00 s). The average particle sizes of the RPJPs were 14.92 µm, 19.68 µm, 19.36 µm, 17.58 µm, 19.96 µm, 19.41 µm, and 18.72 µm for RPJP + MD, RPJP + WP, RPJP + GA, RPJP + MD + WP, RPJP + MD + GA, RPJP + WP + GA, and RPJP + MD + WP + GA respectively. Despite the low powder yield and high water activity value, RPJP + MD exhibited superior (bulk density, flowability, cohesiveness, wettability and solubility times) or statistically similar (productivity, moisture content, browning index, porosity, dispersibility, and hygroscopicity) properties compared to other powders.

Powder Reuse Cycles in Electron Beam Powder Bed Fusion-Variation of Powder Characteristics.

A path to lowering the economic barrier associated with the high cost of metal additively manufactured components is to reduce the waste via powder reuse (powder cycled back into the process) and recycling (powder chemically, physically, or thermally processed to recover the original properties) strategies. In electron beam powder bed fusion, there is a possibility of reusing 95-98% of the powder that is not melted. However, there is a lack of systematic studies focusing on quantifying the variation of powder properties induced by number of reuse cycles. This work compares the influence of multiple reuse cycles, as well as powder blends created from reused powder, on various powder characteristics such as the morphology, size distribution, flow properties, packing properties, and chemical composition (oxygen and nitrogen content). It was found that there is an increase in measured response in powder size distribution, tapped density, Hausner ratio, Carr index, basic flow energy, specific energy, dynamic angle of repose, oxygen, and nitrogen content, while the bulk density remained largely unchanged.