Small Powder Research Articles

Advancing laser powder bed fusion with non-spherical powder: Powder-process-structure-property relationships through experimental and analytical studies of fatigue performance

This study investigates the multifaceted interdependencies among powder characteristics (i.e., non-spherical morphology and particle size ranging 50-120 or 75-175µm), laser powder bed fusion (L-PBF) process condition (i.e., contouring), post-process treatments (i.e., hot isostatic pressing (HIP) and mechanical grinding) on the pore, microstructure, surface finish, and fatigue behavior of additively manufactured Ti-6Al-4V samples. Microstructure analysis shows a phase transformation α′ → α+β microstructure after HIP treatment (at 899±14 °C for 2h under the applied pressure of 1034±34bar) of the as-built Ti-6Al-4V parts. The findings from pore analysis using micro-computed tomography (μ-CT) show an increase in sub-surface pores when relatively smaller powders are L-PBF processed including contouring. Surface optical profilometry reveals a decrease in surface roughness when fine powder is L-PBF including contouring. Pore analysis conducted through μ-CT reveals that the presence of lack-of-fusion pores within the L-PBF processed coarse powder is more pronounced when compared to the fine powder. Furthermore, HIP treatment does not eliminate these pores. The fracture failure in as-printed parts occurs at the surface, while the combination of HIP and mechanical grinding alters crack initiation to subsurface pore defects. Fractography reveals that HIP and as-built samples followed the facet formation and pseudo-brittle fracture mechanisms, respectively. Fatigue life assessments, supported by statistical analysis, indicate that mechanical grinding and HIP significantly enhanced fatigue resistance, approaching the benchmarks set by wrought Ti-6Al-4V alloy. A fatigue prediction model which considers the surface roughness as a micro-notch has been used.

Investigations on the dustiness of binary acetaminophen - lactose monohydrate powder blends

In this study, binary powder blends of acetaminophen (ACAM) and α-lactose monohydrate (LM) at different mixing ratios, with fine, medium-size, and coarse particles are investigated with a new two-chamber setup (TCS) to assess dustiness. The TCS consists of an emission and a detection chamber, allowing plain diffusive or convective particle transport. The aim is to compare the diffusive transport of ACAM with binary blends of ACAM and LM at different particle sizes and similar apparent density. Fine ACAM exhibits significantly higher dust emissions compared to medium and coarse ACAM. With increasing LM portion in the blends, ACAM dust emissions decrease. The blend of fine ACAM and coarse LM shows the highest dust emission, while the blend of coarse ACAM and fine LM reveals the lowest emissions. The TCS offers precise, reproducible measurements with good repeatability, making it beneficial for laboratory and industrial applications, even with small powder quantities.

Anisotropic SmFe10V2 Bulk Magnets with Enhanced Coercivity via Ball Milling Process.

Anisotropic bulk magnets of ThMn12-type SmFe10V2 with a high coercivity (Hc) were successfully fabricated. Powders with varying particle sizes were prepared using the ball milling process, where the particle size was controlled with milling time. A decrease in Hc occurred in the heat-treated bulk pressed from large-sized powders, while heavy oxidation excessively occurred in small powders, leading to the decomposition of the SmFe10V2 (1-12) phase. The highest Hc of 8.9 kOe was achieved with powders ball-milled for 5 h due to the formation of the grain boundary phase. To improve the maximum energy product ((BH)max), which is only 2.15 MGOe in the isotropic bulk, anisotropic bulks were prepared using the same powders. The easy alignment direction, confirmed by XRD and EBSD measurements, was <002>. Significant enhancements were observed, with saturation magnetization (Ms) increasing from 59 to 79 emu/g and a remanence ratio (Mr/Ms) of 83.7%. (BH)max reaching 7.85 MGOe. For further improvement of magnetic properties, controlling oxidation is essential to form a uniform grain boundary phase and achieve perfect alignment with small grain size.

Inhalable tobramycin EEG powder formulation for treating Pseudomonas aeruginosa-induced lung infection

Pulmonary delivery of antibiotics is an effective strategy in treating bacterial lung infection for cystic fibrosis patients, by achieving high local drug concentrations and reducing overall systemic exposure compared to systemic administration. However, the inherent anatomical lung defense mechanisms, formulation characteristics, and drug-device combination determine the treatment efficacy of the aerosol delivery approach. In this study, we prepared a new tobramycin (Tobi) dry powder aerosol using excipient enhanced growth (EEG) technology and evaluated the in vitro and in vivo aerosol performance. We further established a Pseudomonas aeruginosa-induced lung infection rat model using an in-house designed novel liquid aerosolizer device. Notably, novel liquid aerosolizer yields comparable lung infection profiles despite administering 3-times lower P. aeruginosa CFU per rat in comparison to the conventional intratracheal administration. Dry powder insufflator (e.g. Penn-Century DP-4) to administer small powder masses to experimental animals is no longer commercially available. To address this gap, we developed a novel rat air-jet dry powder insufflator (Rat AJ DPI) that can emit 68–70 % of the loaded mass for 2 mg and 5 mg of Tobi-EEG powder formulations, achieving a high rat lung deposition efficiency of 79 % and 86 %, respectively. Rat AJ DPI can achieve homogenous distribution of Tobi EEG powder formulations at both loaded mass (2 mg and 5 mg) over all five lung lobes in rats. We then demonstrated that Tobi EEG formulation delivered by Rat AJ DPI can significantly decrease CFU counts in both trachea and lung lobes at 2 mg (p < 0.05) and 5 mg (p < 0.001) loaded mass compared to the untreated P. aeruginosa-infected group. Tobi EEG powder formulation delivered by the novel Rat AJ DPI showed excellent efficiencies in substantially reducing the P. aeruginosa-induced lung infection in rats.

Semi-wet synthesis of high-performance Li1.6Mn1.6O4 for selective lithium extraction from Salt Lakes Brine

Among the manganese-based lithium-ion sieves, Li1.6Mn1.6O4 has a high theoretical lithium adsorption capacity as a spinel ion sieve material. Small particle size orthogonal phase purity LiMnO2 powders were prepared by a semi-wet method and calcined in air at 400 °C to obtain Li1.6Mn1.6O4 a lithium-ion sieve precursor. The synergistic effects of oxygen atmosphere, heat treatment conditions and lithium/manganese molar ratio on the crystal structure of LiMnO2 and the lithium adsorption/desorption characteristics of Li1.6Mn1.6O4 were comprehensively investigated with XRD, SEM, TEM, XPS, Raman, DTA-TG and capacity retention study. Notably, when the initial lithium/manganese molar ratio was set at 1.1, and the sample underwent a calcination at 120 °C for 48 h under carefully controlled deoxygenation conditions, we observed the exclusive presence of the desired orthorhombic phase in the LiMnO2 sample. In contrast, when the synthesis conditions deviated from the optimized parameters led to the presence of the monoclinic phase of Li2MnO3. This highlights the sensitivity of Li1.6Mn1.6O4 properties to the synthesis conditions. The results of adsorption-desorption cycles show that the ion sieve Li1.6Mn1.6O4 prepared by heat treatment of ordered o-LiMnO2 is more stable, the structural stability of Li1.6Mn1.6O4 were characterized by high-temperature in-situ XRD experiments during heating from 30 to 800 °C. The equilibrium adsorption capacity was 34 mg g−1 in Qarhan Salt Lake brine at 10th cycle, and a remarkably low Mn dissolution loss rate of 0.6 %. The results have significant potential to advance the development of high-performance adsorbent in the Li-Mn-O system and contribute to the advances in lithium separation technology.

Preparation of three-dimensionally interconnected sulfur-deficient MoS2/nitrogen-doped carbon composite via salt template method for separator modification in lithium–Sulfur batteries

Separator modification is a promising strategy with regard to lithium–sulfur batteries for trapping polysulfides and suppressing the involved shuttle effect. Herein, a sulfur-deficient molybdenum disulfide/nitrogen-doped carbon composite with an open and interconnected structure (IMoS2-x) was synthesized through facile salt template method using recrystallized salt powder. Unlike the two-dimensional sheet structure obtained through conventional salt template method, an effective three-dimensional IMoS2-x composite design can be achieved using small salt powder as a template. The prepared IMoS2-x-coated polypropylene separator (referred to as IMoS2-x/PP) exhibited remarkable electrochemical performances such as high initial discharge capacity of 1405.1 mAh/g and rate capability of 754.16 mAh/g at 0.1 and 3C, respectively. Furthermore, IMoS2-x/PP exhibited robust cycling performance of 911.18 mAh/g after 80 cycles at 0.2C under high sulfur loading and lean electrolyte conditions, with the electrolyte-to-sulfur ratio (E/S ratio) of 7.5 μL mg−1.

Nutrient composition of dried marine small fish in Bangladesh and their potential to address hidden hunger

This study investigates the nutrient composition of fish powder intended for direct consumption, sourced from seven small fish species indigenous to the Bay of Bengal, Bangladesh. Locally known as chapila, chewa, faissa, ichre, loittya, mola, and olua, these fish were collected, dried to a moisture content consistent with local practices, pulverized, and subjected to analysis for proximate composition, mineral content, vitamin levels, heavy metal presence, and fatty acid profile. While the dried fish samples exhibited high nutritional quality, significant variations were observed among species for each nutrient analyzed. Consequently, no single species emerged as superior when considering all nutritional factors collectively. However, consuming 10 g of dried small fish powder sourced from the analyzed species could potentially fulfill 100% of the recommended nutrient intake (RNI) for protein, calcium, selenium, and vitamin B12 among children aged 6–23 months. Moreover, its serves as a significant source of these nutrients for pregnant or lactating women. Importantly, this intake level does not pose any risk associated with mercury or cadmium content. These findings hold promise as a valuable addition to the national food composition table, offering insights into the utilization of dried small fish from marine sources as a potent tool in the fight against malnutrition.

Effects of spray drying temperature on physicochemical properties of grapeseed oil microcapsules and the encapsulation efficiency of pterostilbene

Pterostilbene (PTE) grapeseed oil emulsion was prepared by spray drying. The effects of spray drying temperature (100 °C–180 °C) on the physical properties, encapsulation efficiency of PTE, and volatile organic compounds were studied. The microcapsule powder formed at 140 °C had a high yield (53.14%), good particle integrity, and small powder particle size, and the corresponding reconstituted emulsion had a small droplet size. With the spray drying temperature increasing from 100 to 180 °C, the encapsulation efficiency of PTE in microcapsule powder decreased from 74.6% to 55.2%. The results of electronic nose and GC-IMS showed that the aroma components of grapeseed oil, such as 2-methyl butyraldehyde, 3-methyl butyraldehyde, acetone, butanone, ethanol, and 1-hexanol were well preserved after emulsification and spray drying. The results of this study are expected to promote the development of PTE-containing grapeseed oil microcapsule products for functional foods.

Nutritional Contribution of Awaous sp Small Indigeneous Fish Powder Important for the First 1000 Days of Life

Research facts prove that small-sized fish are essential nutrition during the first 1000 days of life. Central Sulawesi Province has an endemic small-sized marine fish species locally known as duo or penja fish (Awaous sp), which has not been studied for its bio-mineral content. This study aimed to analyze the moisture, ash, protein, calcium, iron, and zinc content in Awaous sp protein flour. This research was a descriptive laboratory study conducted at the Ilmu Bahan Makanan Laboratory Department of Nutrition Poltekkes Kemenkes Palu and PT. Saraswanti Indo Genetech Laboratory, Bogor, West Java, from January to September 2023. The sampling technique used purposive sampling, which involved purchasing fish from the local market in Palu city. Awaous sp protein flour had a moisture, ash, protein, Ca, Fe, and Zn content of 3.89%, 9.71%, 73.53%, 2316.88 mg/100g, 24.54 mg/100g, and 8.97 mg/100g, respectively. The contribution per serving of 145 grams of Awaous sp fish flour met the nutritional requirements (Recommended Dietary Allowances - RDA) for protein, Ca, Fe, and Zn per person per day for infants aged 6-11 months, children aged 1-3 years, pregnant women, and lactating women. Awaous sp protein flour had higher protein and Fe content compared to other small fish and had the potential to meet RDA requirements. Therefore, consuming Awaous sp protein flour as part of the daily diet can be a suitable strategy to address nutritional deficiencies during the first 1000 days of life for residents in Central Sulawesi.

Experimental investigation on selective laser melting additive manufacturing of non-ferromagnetic heterogeneous material based on TiNi alloy with Ta coating

In order to manufacture non-ferromagnetic heterogeneous material by Selective Laser Melting (SLM), it is necessary to solve the separation problem of non-ferromagnetic mixed powders after SLM forming. This research presents how to resolve this problem using TiNi/Ta mixed powders by ultrasonic vibration screening method and the analysis of SLM manufacturing experiment for non-ferromagnetic heterogeneous material. The purity of TiNi and Ta powders after separation could reach 99.7087%wt% and 98.8501wt% respectively, which both reached a relatively high purity. A TiNi alloy sample with Ta coating and TiNi/Ta gradient transition was manufactured successfully by SLM. The material interface of the sample achieves metallurgical bonding, and the color of the sample profile shows a gradient transition. The EDS analysis shows that the material composition changes from Ta -&gt;Ta/TiNi gradient -&gt;TiNi from surface to inside of the sample. The Ta coating contains over 92.5wt% Ta, and the TiNi matrix contains over 98.69wt% TiNi. Along the powder laying direction, it is difficult to clean the small powder near the solid-powder or solid-solid interfaces made of two different materials, which causes micro polluted areas near the interfaces. This study also provides a new method for integrated manufacturing of TiNi alloy part with Ta coating.

Multiphysics modelling of powder bed fusion for polymers

ABSTRACT Polymeric materials for powder bed fusion additive manufacturing have been attracting extensive research interest due to their vast potential for fabricating end-use functional parts. Here, a high-fidelity multiphysics approach combining the discrete element model with the computational fluid dynamics model has been developed to simulate the printing process of polymers in powder bed fusion, involving powder recoating, melting, and coalescence. The developed approach considers particle flow dynamics, the reflection, absorption, and transmission of infrared laser radiation, and the viscous flow of polymer melt. The pore formation mechanisms due to lack of fusion and gas entrapment in polyamide 12 parts printed via selective laser sintering are studied. The simulation results reveal that lower polymer viscosity would be beneficial to the densification rate of the printed parts. Excessively small powder particles would degrade powder bed quality due to the agglomeration of polymer powder, thus leading to high porosity in the printed parts.

Significant reduction in processing time for Ca0.95Ce0.05MnO3 thermoelectric ceramics

Attrition-milling process has been applied to Ce-doped CaMnO3 precursors to obtain small grain-size powders. The use of Ce4+ as dopant instead a Rare Earth3+ has allowed decreasing by 50% the atomic proportion of dopant, to obtain equivalent charge carrier concentration, which is required for attaining promising properties for thermoelectric applications. An impressive decrease in thermal processing time was achieved, together with an increase in thermoelectric performances, when compared to classically prepared materials. XRD and SEM analysis have confirmed that the final material is nearly single phase. Moreover, grain sizes and density increase with the sintering duration. These microstructural differences are reflected in a significant decrease in electrical resistivity, when compared to the samples prepared from ball-milled precursors (used as reference), without drastically modifying the Seebeck coefficient values. On the other hand, despite of their high electrical conductivity, thermal conductivity is decreased for short time sintered materials, leading to the highest ZT values at 800 °C (∼0.27) in samples sintered for 1 h at 1310 °C. These values are among the best reported in the literature, but they have been obtained in very short time using a simple, and easily scalable process. The suggested approach presented in this work appears particularly promising for large-scale production of oxide-based thermoelectric modules for power generation.

The Kinetic Mechanism of the Thermal Decomposition Reaction of Small Particles of Limestone at Steelmaking Temperatures

Converter blowing limestone powder making slag steelmaking process has the advantages of low carbon and high efficiency, and can realize the resource utilization of CO2 in the metallurgical process, which is in line with the development direction of green metallurgy. Based on a thermogravimetric-differential thermal analyzer, the kinetic mechanism of decomposition of small limestone at steelmaking temperatures was investigated by a modified double extrapolation method. The results showed that with a higher rate of heating, limestone decomposition lagged, and decomposition temperature increased. Furthermore, the smaller the limestone particle size, the lower the activation energy of decomposition. Compared with N2, air, and O2, small limestone powder used for converter blowing could complete more rapid decomposition, and the time required for decomposition shortened by about 1/3, although the decomposition temperature increased in the CO2. The limestone decomposition rate increased and then decreased at low to high CO2 partial pressures. With a limiting link, the inhibition was more significant under high CO2 partial pressure, but the reaction can be fully completed by 1000 °C. The decomposition type modeled was stochastic nucleation and subsequent growth. As the partial pressure of CO2 increased from 25% to 100%, the number of reaction stages, n, increased.

Environmental impact of wall multilayer coating systems containing aerogel-based fibre-enhanced thermal renders

This research evaluates the environmental impacts of aerogel-based fibre-enhanced thermal insulating renders and the respective multi-layered coating system to apply on buildings' envelopes, contributing to their energy efficiency. The environmental analysis was performed using a Life Cycle Assessment (LCA) methodology with a cradle to gate approach, including the Life Cycle Inventory (LCI) of the protective coating system while evaluating the Abiotic Depletion Potential from fossil fuels (ADP-ff) and the Global Warming Potential (GWP). A sensitivity analysis of the silica aerogel aggregate contribution to the overall environmental impacts was also carried out, and a study of the impact that the introduction of natural and synthetic fibres had on the thermal render’ formulation. The results showed that the most critical environmental contribution is related to the raw materials incorporated in the thermal render representing more than 90% of the total environmental impact when a cradle to gate analysis is made. It was also verified that even a small powder substitution by natural and synthetic fibres (0.10–0.50% of the total powder volume) could have significant impacts on the environmental performance of the aerogel-based thermal render. This research also showed that these thermal renders, although at a developing stage, show a promising application potential from the environmental point of view and that further optimisation steps can lead to even lower impacts.

Suppression method of industrial Al alloy powder explosion in dry and humid environment: A low-cost intrinsic safety technology

During the production and processing of Al alloy, a large number of small particle size powders will be produced. If the concentration of these Al alloy dust is too high under dry conditions, it will lead to dry powder explosion, and if hydrogen is produced in contact with water under wet conditions, it will lead to hydrogen explosion. This work is intended to develop a simple, cost effective technology that inerts waste Al alloy dust and minimizes its explosion hazards in different environments. Dihydrogen phosphates (KH2PO4, NH4H2PO4, Ca(H2PO4)2) are used to test the explosion flame propagation, explosion pressure, and hydrogen evolution, of waste Al alloy dust. The results show that dihydrogen phosphate can significantly reduce the flame propagation distance, speed, explosion pressure and hydrogen evolution performance of Al alloy dust, and inhibit the explosion of Al alloy dust in dry and humid environment to varying degrees. In different experiments, Ca(H2PO4)2 has the best inerting effect, low cost and simple operation, which realizes the intrinsic safety of metal dust processing process. The phosphating film on the surface of Al alloy particles blocks the generation of Al(OH)3 and retains the metal body to the greatest extent, which provides a possibility for the recycling of waste metal dust.

Solidification Behavior of Fe-6.5Si Alloy Powder for AM-SLM Processing, as Assessed by Differential Scanning Calorimetry.

Lab-scale investigations on the processing of small powder volumes are of special importance for applications in additive manufacturing (AM) techniques. Due to the technological importance of high-silicon electrical steel, and the increasing need for optimal near-net-shape AM processing, the aim of this study was to investigate the thermal behavior of a high-alloy Fe-Si powder for AM. An Fe-6.5wt%Si spherical powder was characterized using chemical, metallographic, and thermal analyses. Before thermal processing, the surface oxidation of the as-received powder particles was observed by metallography and confirmed by microanalysis (FE-SEM/EDS). The melting, as well as the solidification behavior of the powder, was evaluated using differential scanning calorimetry (DSC). Due to the remelting of the powder, a significant loss of silicon occurred. The morphology and microstructure analyses of the solidified Fe-6.5wt%Si revealed the formation of needle-shaped eutectics in a ferrite matrix. The presence of a high-temperature phase of silica was confirmed by the Scheil-Gulliver solidification model for the ternary model Fe-6.5wt%Si-1.0wt%O alloy. In contrast, for the binary model Fe-6.5wt%Si alloy, thermodynamic calculations predict the solidification exclusively with the precipitation of b.c.c. ferrite. The presence of high-temperature eutectics of silica in the microstructure is a significant weakness for the efficiency of the magnetization processes of soft magnetic materials from the Fe-Si alloy system.

Development of artificial neural network based mathematical models for predicting small scale quarry powder factor for efficient fragmentation coupled with uniformity index model

Blasting is the primary method for reducing rock size in small-scale mining operations. The primary purpose of blasting is to assist rock mass reduction and transportation from the mine to the processing facility. The explosive charge utilized in this blasting operation has an impact on production output, safety, and profitability. The explosive powder factor is used in mining to calculate the quantity of explosive required per mass of rock fragmented, and this study looks at how different powder factors affect blast fragmentation. A machine learning approach was used in this study to optimize explosive use in small-scale quarries. This study employed data from a small-scale dolomite quarry in Akoko Edo, Nigeria, for artificial neural network (ANN) modeling and uniformity index model creation (10 production blasts and 38 blast record datasets). Powder factors greater than 0.7–0.8 kg/m3 result in a lower uniformity index, according to an analysis of monitored blast results. The results showed that powder factors of 0.7 kg/m3 (between 1.6 and 1.7) had the highest uniformity index. According to the findings, the small-scale optimum blast uniformity index is between 1.33 and 1.68. The proposed ANN model performs well in terms of prediction accuracy, as determined by five error indices with coefficients of correlation (R2) of 0.997 on the training dataset and 0.97 on the testing dataset. Based on the model performance analysis results, the suggested ANN model can be used to improve the small-scale blast powder factor in actual applications.

Utility of biphasic calcium phosphate cement as a seal for root-end filling.

The recently developed biphasic calcium phosphate cement (BCPC) consists of α-tricalcium phosphate-tetracalcium phosphate as the solid phase and calcium phosphate solution as the liquid phase. BCPC powder is composed of a single solid solution with a monomodal size distribution. Here, we used a bacterial leakage model to examine the utility of BCPC as a seal for root-end filling. We prepared large (median particle size=9.96 µm; BCPC-L) and small (median particle size=4.84 µm; BCPC-S) BCPC powders. In total, 45 single-rooted teeth were instrumented, resected at the root-end, and retrofilled with experimental materials. Mineral trioxide aggregate (MTA) was used as the control. After visual confirmation of BCPC powder size and retrofilling quality by microscopy, bacterial leakage tests were conducted using Enterococcus faecalis. The bacterial leakage tests did not reveal any significant differences between BCPC-S and MTA. Our findings suggest that BCPC-S is useful for root-end filling.

Effects of Marine Residue-Derived Fertilizers on Strawberry Growth, Nutrient Content, Fruit Yield and Quality

An outdoor experiment was performed for six months to evaluate the effects of organic fertilizers obtained from marine residual materials on strawberry plants. Three types of organic fertilizers were used, i.e., cod (Gadus morhua) bone powder, common ling (Molva molva) bone powder, and pellets obtained by mixing small cod bone powder and rockweed (Ascophyllum nodosum) residues. A tabletop system for strawberry cultivation was designed, in which two bare-root strawberry plants of cultivar ‘Albion’ were planted in a peat substrate in each pot. Five treatments were applied, i.e., cod bone powder (F1), common ling bone powder (F2), small cod bone powder and rockweed residue pellets (FA), chemical fertilizer (E), and a control (C). The number of leaves and their nutrient content, fruit yield and quality characteristics of the strawberries grown using the organic fertilizers were similar or better than those corresponding to treatments E and C. Organic fertilizers derived from the residues of fish and macroalgae could be a promising alternative to chemical fertilizers in strawberry production.

New Air-Jet Dry Powder Insufflator for High-Efficiency Aerosol Delivery to Rats.

Pulmonary deposition of lung-targeted therapeutic aerosols can achieve direct drug delivery to the site of action, thereby enhancing the efficacy and reducing systemic exposure. In this study, we investigated the in vitro and in vivo aerosol performance of the novel small animal air-jet dry powder insufflator (Rat AJ DPI) using spray-dried albuterol excipient-enhanced-growth (EEG) powder as a model formulation. The in vitro aerosolization performance of the optimized albuterol EEG powder was first assessed using the Rat AJ DPI. The performance of Rat AJ DPI to deliver albuterol EEG aerosol to rat lungs was then compared to that of the Penn-Century Insufflator. Albuterol EEG powders dispersed using the Rat AJ DPI demonstrated narrow unimodal aerosol size distribution profiles, which were independent of the loaded powder dose (1, 2, and 5 mg). In addition, the span value for Rat AJ DPI (5 mg powder mass) was 1.32, which was 4.2-fold lower than that for Penn-Century insufflator (5 mg powder mass). At a higher loaded mass of 5 mg, the Rat AJ DPI delivered significantly larger doses to rat lungs compared with the Penn-Century DPI. The Rat AJ DPI with hand actuation delivered approximately 85% of the total emitted dose (2 and 5 mg loadings), which was comparatively higher than that for Penn-Century DPI (approximately 75%). In addition, percentage deposition in each of the lung lobes for the Rat AJ DPI was observed to be independent of the administration dose (2 and 5 mg loadings) with coefficients of variation below 12%, except in the right middle lobe. Automatic actuation of a 5 mg powder mass using the Rat AJ DPI demonstrated a similar delivered dose compared to manual actuation of the same dose, with 82% of the total emitted dose reaching the lung lobes. High-efficiency delivery of the aerosol to the lobar lung region and low sensitivity of the interlobar delivery efficiency to the loaded dose highlight the suitability of the new air-jet DPI for administering therapeutic pharmaceutical aerosols to small test animals.