Alumina Particles Research Articles

INFLUENCE OF FILLER SIZE ON THE STRUCTURE AND PROPERTIES OF THE POLYMER MATRIX

Purpose. The aim of the study is to investigate the influence of aluminum oxide (Al2O3) particle size on the mechanical properties of a polymer composite with added chopped glass fiber, as well as to explore the interaction between aluminum oxide particles and chopped glass fiber. Research methods. Specimens were tested for tensile strength according to DSTU EN ISO 527-5:2018. Testing was conducted using an MTS Criterion Model 43 universal testing machine with a maximum load of 50 kN. Metallographic analysis was performed using a KEYENCE VHX microscope at magnifications of 50× and 500×. The microstructure of the polymer matrix was determined on unetched samples. Scanning electron microscopy was carried out using a JEOL JSM-5510LV microscope. Results. The influence of introducing different sizes of aluminum oxide fraction on the polymer matrix was studied. It was found that with an increase in the fraction size, the strength of the polymer composition decreases. Additionally, the interaction between chopped glass fiber and various fractions of aluminum oxide on the mechanical characteristics and morphology of the connection with the polymer composition was investigated. Scientific novelty. The interaction of chopped fiber with aluminum oxide fractions may affect the mechanical properties of the composite, such as strength, stiffness, and elasticity. Investigation of the morphology of the connection between chopped fiber and aluminum oxide fractions can help understand how they interact within the composite structure. This includes analyzing the adhesion between components, the structure of junctions, and possible defects that may arise during the manufacturing process. Studying this interaction opens up opportunities for the development of new composite materials with improved properties and diverse applications in industry, construction, aviation, automotive, and other fields. Practical value. The practical significance lies in refining manufacturing technologies and implementing new materials in industry. The ability to control the mechanical properties of composites by changing the size of aluminum oxide fractions can contribute to the creation of more efficient materials for the production of automobiles, aircraft, building constructions, and more. Additionally, understanding the interaction between chopped glass fiber and aluminum oxide fractions may open up new possibilities for developing composites with unique mechanical characteristics that meet the requirements of modern technologies and industrial production.

Thermally conductive, mechanically robust alumina-incorporated polyurethane films prepared by ultraviolet light curing

Abstract The development of heat dissipating composite materials for electronic systems can be expedited using alumina particles as modifiable polymer-matrix fillers. However, these composites are difficult to synthesize given the tradeoffs between thermal conductivity, insulating characteristics, and conduciveness to processing. To that end, the present study is focused on synthesizing environmentally friendly polyurethane films that could be cured by ultraviolet light within minutes, without requiring high-temperature heat treatment. Through the optimization of alumina modification, hybridization of thermally conductive fillers, filler content, and stirring time on the thermal conductivity of the polyurethane composites, this study improves the process for sustainability, low-cost, and convenient preparation. The experimental results confirmed that the use of surface modification and hybrid fillers is effective for enhancing the thermal conductivity, with the value of the polyurethane integrated with 50 wt% Al2O3 and 5 wt% Al2O3–poly (catechol/polyamine) being 76.40 wt% higher than that of pure PU (0.44 W/mK). Additionally, the use of hybrid fillers resulted in superior mechanical and thermal properties (such as tensile strain, tensile strength, thermal expansion coefficient, and temperature resistance) compared with those of pure PU and films incorporated with only a single filler.

Impact of nanoparticle shape on the thermal performance of eco-friendly soybean-based nanofluids in cooling titanium alloys

Ecofriendly soybean coolant offers a sustainable alternative to conventional coolants, providing excellent thermal performance while reducing environmental impact. Its biodegradable nature and low toxicity make it a safe choice for various cooling applications, promoting greener industrial practices. This study investigates the thermal performance of eco-friendly soybean nanofluids dispersed with alumina and molybdenum disulfide (MoS2) nanoparticles for cooling a titanium alloy block. The investigations are conducted using single and dual nozzle setup to assess the impact of nanoparticle shape, volume fraction and Reynolds number on heat transfer characteristics of ecofriendy coolant. The discretization is conducted using the finite volume method, and the Nusselt number is calculated from the convective heat transfer coefficient. Results show that platelet-shaped nanoparticles exhibit superior thermal conductivity and heat transfer performance compared to spherical and cylindrical shapes. Increasing the volume fraction of MoS2 platelet-shaped nanoparticles from 0.5% to 6% results in a reduction of the average temperature distribution of the titanium block by 26.53% in the single-nozzle setup and 28.87% in the dual-nozzle configuration. The dual nozzle arrangements significantly enhance heat dissipation, with MoS2 nanoparticles decreasing the temperature distribution by 9.24% in the single-nozzle setup and 15.78% in the dual-nozzle setup compared to alumina nanoparticles. Optimal thermal performance is observed at elevated Reynolds numbers, where platelet-shaped MoS2 nanoparticles achieve the highest Nusselt numbers. Specifically, incorporating MoS2 cylindrical-shaped nanoparticles into soybean oil at higher Reynolds numbers improves average heat transfer by up to 29.16% when compared to cylindrical alumina nanoparticles. The enhancements in heat transfer for spherical and platelet-shaped MoS2 nanoparticles are 37.51% and 46.66%, respectively, relative to cylindrical alumina particles. This research offers crucial guidance on developing and enhancing sustainable coolants, revealing the significance of nanoparticle shape in optimizing thermal performance and paving the way for cleaner production processes that prioritize environmental responsibility.

In Situ Fabrication of Al@C Nanocomposite Energetic Additives via Pulsed Discharge in Cyclohexane

ABSTRACTA method for in situ fabrication of Al@C nanocomposite energetic additives through pulsed discharge in liquid cyclohexane has been proposed. The obtained Al@C nanocomposites consist of large aluminum nanoparticles (over 100 nm) enveloped by fullerenes and a carbon matrix with smaller aluminum particles (under 100 nm) embedded within. DSC–TGA curves indicate that the heat release of Al@C is higher than that of micron‐sized and nano‐sized aluminum particles. Al@C nanocomposites effectively reduce the ignition delay for liquid fuels. The energy efficiency of this method is much higher than that of continuous arc ablation, with a yield of up to 2.5 mg/min. This method allows for the simple, convenient, and safe fabrication of energetic additives, presenting a promising prospect for large‐scale industrial production.

Effects of zirconium diboride addition on porosity reduction in laser metal deposition of tungsten carbide–cobalt cermet material

Laser metal deposition of tungsten carbide–cobalt (WC-Co) cermet material is a promising means of improving the wear resistance of metal products. However, laser metal deposition of WC-Co has constraints on its practical use because a clad bead of WC-Co often includes numerous gas pores. Earlier studies have found CO gas generation in a molten pool by reaction of carbon and oxygen to be the main cause of gas porosity in a WC-Co clad bead. Preventing the gas reaction is important to obtain clad beads with few pores. The addition of elements with strong affinity for oxygen, such as aluminum, was found to be effective for porosity reduction in a clad bead. However, the addition of highly reactive pure aluminum particles on WC-Co powder presents some difficulties for industrial use. For this study, zirconium diboride (ZrB2), a chemically stable compound, was used as an additive to WC-Co powder. After WC-Co powder with adhered ZrB2 particles was prepared using a wet granulation process, laser metal deposition was conducted. Zirconium stemming from the dissolution of ZrB2 in the molten pool was found to have the effect of trapping oxygen elements as solid zirconium oxides. Consequently, gas generation in the molten pool by the reaction of carbon and oxygen was restrained. Clad beads having few pores and fine microstructures were obtained. Observations of the molten pool behavior taken using a high-speed camera indicated that ZrB2 addition drastically improves process stability compared to processes using conventional WC-Co powder.

Morphology engineering of low-temperature-synthesized aluminum nitride

We have developed an aluminum nitride (AlN) manufacturing method that operates below the melting point of aluminum. To examine the nucleation and growth mechanisms of AlN during the synthesis process, we used a variety of characterization techniques, including high-resolution transmission electron microscopy and rapid Fourier transform, which highlighted the development of its single-crystal and polycrystalline forms. The microstructural investigation showed that nitridation began with forming AlN shells on the surface of aluminum particles. Subsequently, volume nitridation occurred by transforming a single aluminum particle into either polycrystalline AlN with a columnar structure or single-crystal AlN. In addition, various interesting morphologies were observed during the microstructural investigation of low-temperature synthesized AlN, including truncated dodecahedrons, nanowires, particles, pillars, plates, and other polyhedral shapes. The study's microstructural findings provide crucial data on the AlN particle formation process, offering valuable insights expected to deepen understanding and expand the applications of AlN. Therefore, the consequence of this study is expected to make a meaningful contribution to understanding the formation mechanism of the particle type of AlN.

Sol-Gel Derived Alumina Particles for the Reinforcement of Copper Films on Brass Substrates.

The aim of this study is to provide tailored alumina particles suitable for reinforcing the metal matrix film. The sol-gel method was chosen to prepare particles of submicron size and to control crystal structure by calcination. In this study, copper-based metal matrix composite (MMC) films are developed on brass substrates with different electrodeposition times and alumina concentrations. Scanning electron microscopy (FE-SEM) with energy-dispersive spectroscopy (EDS), TEM, and X-ray diffraction (XRD) were used to characterize the reinforcing phase. The MMC Cu-Al2O3 films were synthesized electrochemically using the co-electrodeposition method. Microstructural and topographical analyses of pure (alumina-free) Cu films and the Cu films with incorporated Al2O3 particles were performed using FE-SEM/EDS and AFM, respectively. Hardness and adhesion resistance were investigated using the Vickers microindentation test and evaluated by applying the Chen-Gao (C-G) mathematical model. The sessile drop method was used for measuring contact angles for water. The microhardness and adhesion of the MMC Cu-Al2O3 films are improved when Al2O3 is added. The concentration of alumina particles in the electrolyte correlates with an increase in absolute film hardness in the way that 1.0 wt.% of alumina in electrolytes results in a 9.96% increase compared to the pure copper film, and the improvement is maximal in the film obtained from electrolytes containing 3.0 wt.% alumina giving the film 2.128 GPa, a 134% hardness value of that of the pure copper film. The surface roughness of the MMC film increased from 2.8 to 6.9 times compared to the Cu film without particles. The decrease in the water contact angle of Cu films with incorporated alumina particles relative to the pure Cu films was from 84.94° to 58.78°.

Ignition and Combustion of Aluminum Hydride Dust Aerosols

ABSTRACT The results of comparative experimental studies of aluminum hydride AlH3 and aluminum Al particle aerosols, in particular, of the critical conditions for auto-ignition and the features of the flame propagation in low-volume (V ≈ 5.1·10−3 m3) and large clouds (volume is varied from 40 to 60 m3) are presented in this article. Experiments have shown that for aerosols of AlH3 particles, the auto-ignition temperature is much lower than for aluminum particles. This is due to the thermal decomposition of aluminum hydride into hydrogen and active aluminum. The laminar flame was studied in low-volume clouds. A two-frontal form of a laminar flame wave in AlH3 aerosol was found. Moreover, the visible flame propagation speeds for AlH3 correspond to those for finely dispersed Al and are two times higher compared to coarse Al. The turbulent flame in the large free clouds of aluminum hydride dusts has flame propagation speeds several times higher than those in the aluminum clouds and is characterized by the formation of a toroid vortex with a complex internal structure.

Investigation on the microstructure and compressive behavior of open-cell copper- Al2O3 composite foams

The objective of this study is to evaluate the mechanical behavior and energy absorption characteristics of open-cell copper- Al2O3 composite foams fabricated using polyurethane foam with an average pore size of 1.2 mm and a combination of electroless and electrodeposition methods. During electroplating process, the composite foams were fabricated with varying amounts of Al2O3 particles (0.1, 0.6, 0.8, and 1 g/l) in electrolyte solution. To assess mechanical properties of the fabricated foams, uniaxial compression test was conducted to determine the maximum compressive strength, energy absorption density, efficiency, and specific energy absorption. The content of Al2O3 in the fabricated composite foams was evaluated using energy dispersive X-ray (EDX) analysis, and the microstructure was examined using scanning electron microscopy (SEM). The results indicate that the incorporation of Al2O3 particles significantly improves the mechanical properties of the copper-Al2O3 composite foam. Specifically, in the composite foam with 9.34 vol% of Al2O3 particles, the maximum compressive strength, total energy absorption, specific energy absorption, and energy absorption efficiency reach 1.03 MPa, 6.48 MJ m−3, 1.9 J g−1, and 75%, respectively. This amount of alumina particles enhances the maximum compressive strength and total energy absorption of open-cell copper foam by approximately 30% and 100%, respectively. However, the mentioned parameters slightly decreased with an increasing amount of Al2O3 particles up to 16.32 vol%. These significant improvements in the mechanical properties of these foams make them well-suited for high-strength applications.

Effects of Size and Mechanical Pre-Treatment on Aluminium Recovery from Municipal Solid Waste Incineration Bottom Ash

Municipal solid waste (MSW) is incinerated to reduce the volume and recover energy and materials. The generation of MSW has been increasing over the past few decades due to the increase in population and changing consumption habits. Rising environmental and economic concerns have increased the importance of waste treatment and recovery. Currently, MSW may take three alternate or parallel routes: direct recycling, incineration, or landfill, depending on the country and location. MSW incineration has three products in addition to energy: bottom ash, fly ash, and off-gas. After incineration, bottom ash usually still contains many materials to be recovered, such as glass, ceramics, and metals with a degree of oxidation. This study focuses on aluminium recovery from MSW incineration bottom ash from two different countries. The 2–30 mm fraction of aluminium particles was characterized in terms of its size, shape, and oxide thickness, and its effects on aluminium recovery were investigated. In addition, the ability of mechanical pre-treatment to remove oxides prior to melting was studied. The results were compared with the analytical modeling developed in this study. An increasing particle size and surface area resulted in an increase in aluminium recovery. Mechanical pre-treatment increased the yield for smaller particles to a larger extent than larger particles due to the difference in the oxide/metal ratio.

Wire EDM machining characteristics of squeeze cast Al-Zn-Mg-Cu/(SiC + Al2O3) hybrid composite by TOPSIS approach

This research focuses on the squeeze-cast Al-Zn-Mg-Cu metal matrix reinforced with 10% silicon carbide and 10% aluminium oxide particles machined by wire-cut electro-discharge machining (WEDM) to examine the consequences of input factors like pulse-on time, current, pulse-off time, and wire speed over the responses of metal removal rate (MRR) and surface roughness. The pulse-on time (7–11 µs), current (2–4 amps), pulse-off time (6–10 µs), and wire speed (1–3 m/min) used during WEDM machining are all variable. The TOPSIS approach was utilised to identify the optimal processing settings. According to the optimised findings, larger MRR of 3.95 mm3/min and reduced surface roughness of 3.295 µm were achieved by combining pulse-on time, current, pulse-off time and wire speed at 7 µs, 2 amp, 6 µs and 1 m/min, respectively. With a scanning electron microscope, the machined surfaces are examined. Based on the study of the machined surface, the micrograph of sample order no. 1, which has relatively less hills and gorges, has a ton of 7 µs, toff of 6 µs, current of 2 amps and wire speed of 1 m/min. Under a microscope, the amount and size of the craters and fractures created appear to be decreasing. The moderate current intensity and low pulse-off time result in a reduction in the intensity of the electrical discharge. This enhances the surface finish since there are fewer, smaller craters and fissures. The obtained findings may be used by the manufacturers to improve WEDM machining of Al 7075 reinforced with SiC and Al2O3 particles.

Numerical simulation study of aluminum particle evaporation combustion process based on SPH method

A large variety of metal fuels is usually added to the modern solid rocket propellants to improve the propellant energy and motor specific impulse and to suppress high frequency unstable combustion. Among them, aluminum is the most common additive. The combustion process of aluminum can significantly affect the combustion characteristics of a solid rocket motor. In this paper, the SPH (Smoothed Particle Hydrodynamics) method is used to simulate the combustion process of aluminum particles. First, the SPH discrete equations with an evaporation combustion model are derived. On this basis, the evaporation combustion process of aluminum particles is numerically simulated. The results show that when aluminum particles are heated and evaporated in a static flow field, an alumina shell will be formed on the surface, and further thermal expansion will cause the alumina shell to break. The molten aluminum will spray out, and an aluminum cap will be formed on the surface. The “microburst process” will be similar to the gel droplet. In the convective environment, the flame structure of aluminum particles will be obviously peach shaped, which will wrap aluminum particles at the bottom. The simulation results are consistent with the experimental results.

Numerical study on multiphase combustion characteristics of aluminum-based powder-fueled water ramjet engine

Powder-Fueled Water Ramjet Engine (PFWRE) is of great attraction for high-speed and long-voyage underwater propulsion, as well as air-water trans-media navigation applications due to its high energy density and thrust adjustability. However, the complex multiphase combustion process in the combustor significantly affects engine performance. In this study, a detailed model for aluminum particle combustion in water vapor is developed and validated via literature data as well as the ground direct-connected test we conducted. Thereafter, the numerical study on the multiphase combustion process inside the aluminum-based PFWRE combustor is carried out within the Euler–Lagrange framework using the developed model. Results show that a reverse rotating vortex pair before the primary water injection causes particles to flow back towards the combustor head and leads to product deposition. Aluminum particles external to the powder jet have shorter preheating time than internal particles and burn out in advance. The analysis of the particle combustion process indicates that the flame structure inside the combustor consists of the particle preheating zone, the surface combustion heat release zone, the gas-phase combustion heat release zone, and the post-flame zone. In the present configuration, as the particle size increases from 10 μm to 20 μm, the preheating zone length increases from 35 mm to 85 mm. Meanwhile, heat release from gas-phase combustion decreases, and the average temperature of the combustor head first increases and then decreases. This study not only provides insight into the multiphase combustion characteristics of the aluminum-based PFWRE combustor but also offers guidance for the design of the combustion organization schemes and engine structure optimization.

Effect of alumina or zirconia particles on the performance of lead-free BCZT piezoceramics

The barium titanate derivative Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) offers high dielectric and piezoelectric performance but has poor mechanical properties. Ceramic composite materials combining BCZT with tougher Al2O3 or ZrO2 could be the solution to the inherent brittleness of electroceramics. This work focuses on BCZT with 1–5 vol.% addition of reinforcing phase dispersed in the microstructure. While hardness was improved in all composites, especially in ZrO2-reinforced BCZT, toughness was positively affected only by Al2O3. The chemical reactivity of BCZT during sintering resulted in the formation of new barium aluminate phases at the grain boundaries and possibly also within the grains, which affected the electrical properties of the composites. The addition of zirconia resulted in the formation of BaZrO3 or Ba(Zr,Ti)O3, which is a natural part of the BCZT solid solution and shifts the phase composition towards relaxor behaviour. ZrO2-reinforced composites exhibited higher permittivity but lower ferroelectric properties, accompanied by a substantial Curie temperature decrease.

Investigation into the mechanism of ignition of magnesium alloy plates by high-temperature molten droplet

The ignition and spread of magnesium alloy fires are mainly attributed to the ignition of high-temperature molten metal droplets, but the underlying ignition mechanism remains unclear. This study addresses this knowledge gap by employing metallic aluminum and copper particles heated to temperatures over 1200 °C. Systematically, these heated particles were released at a fixed rate onto a magnesium alloy plate located inside a controlled heating furnace that maintained a constant temperature of 500 °C. Experimental results show that whether there are irregular pores and cracks in the resulting molten product can be used as a criterion for judging whether the magnesium alloy sample ignites. Furthermore, it is worth noting that molten copper droplets of the same size exhibit a higher heat-carrying capacity than their aluminum counterparts when both are heated to the same temperature. In addition, this study expanded the research scope through numerical simulation and analysis, using the PATO (Porous-Material Analysis Toolbox) solver to clarify the transient heat conduction process between the high-temperature droplet and the magnesium alloy plate. Simulations show that heat transfer upon droplet impact is primarily longitudinal, directed toward the base of the material. This results in a significantly higher temperature in the center of the affected magnesium alloy plate than at its periphery. In summary, this study helps to improve the understanding of the dangers of high-temperature molten droplets, and it is of great significance to investigate fire accidents caused by high-temperature molten droplets.

Development and characterization of PLA nanocomposites reinforced with bio-ceramic particles for orthognathic implants: Enhanced mechanical and biological properties.

The clinical application of osteofixation materials is crucial for maxillofacial reconstruction and orthognathic surgeries. To overcome the limitations of traditional metallic implants, bioabsorbable materials are gaining popularity due to their ability to avoid secondary removal surgeries and reduce stress shielding. This study investigates third-generation biomaterials, focusing on polylactic acid (PLA) for its biocompatibility and biodegradability, and hydroxyapatite (HAP) for its bioactive osteoconductive and bioresorbable properties. Eggshell nanoparticles (ES-NP), HAP, and bioinert alumina particles coated with titanium dioxide (TiO2@Al2O3) were prepared using ball milling, co-precipitation, and sol-gel methods, respectively. PLA-based nanocomposites PLA/ESNP/Al2O3 (PEA), PLA/HAP/Al2O3 (PHA), PLA/ESNP/TiO2@Al2O3 (PEAT), and PLA/HAP/TiO2@Al2O3 (PHAT) were fabricated via solvent casting. Characterization techniques including X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), and Field-Emission Scanning Electron Microscopy (FE-SEM) were used to analyze the developed nanoparticles and composites. Results indicated PEAT and PHAT composites exhibited tensile strengths of 33.59 ± 0.38 MPa and 32.46 ± 0.46 MPa, tensile moduli of 1756.17 ± 95.43 MPa and 2367.21 ± 158.84 MPa, and shore d hardness values of 84.10 ± 1.45 SHN and 78.00 ± 2.25 SHN, respectively. Both composites achieved a wettability angle of ~65° and surface roughness below 2.19 μm, enhancing osteoblast adhesion. Additionally, MG63 cell viability was approximately 80 %, and hemolysis rates were below 2.17 %, demonstrating their potential for maxillofacial implant applications.

Polymer Composite Cladding for Selective Frequency Filtration: An Experimental and Modeling Study

Laser selective frequency filtering is currently performed using expensive, heavy, and bulky (millimeters in thickness) ceramic composite claddings around the laser rod, which limits the miniaturization and transportability of the laser. The cladding absorbs undesired spontaneous emissions and reflects the desired wavelength of the "pump" diode. As an improved alternative for the cladding on, say, a diode-pumped solid-state Nd:YAG laser rod, we investigate a spray-coated polymer composite cladding (micrometers in thickness). The polymer composite cladding is easier to process and lighter and has a much smaller volume vs. traditional ceramic composite claddings. The approach is demonstrated on spray-coated glass slides, where cubic samaria (Sm2O3) particles are used as the filler in the polymer composite cladding. The rationale for using samaria as the filler in the composite is its absorption near the laser spontaneous emission wavelength (i.e., 1064 nm) and high reflectivity at the incident pump wavelength (i.e., 808 nm). The addition of a second polymer composite layer loaded with alumina particles enables reduction of the samaria composite layer thickness. The Kubelka-Munk model is shown to successfully predict the experimentally measured optical performance of single and bilayer claddings, making it a reliable design tool for multilayer claddings.

Worldwide Rocket Launch Emissions 2019: An Inventory for Use in Global Models

AbstractThe rate of rocket launches is accelerating, driven by the rapid global development of the space industry. Rocket launches emit gases and particulates into the stratosphere, where they impact the ozone layer via radiative and chemical processes. We create a three‐dimensional per‐vehicle inventory of stratospheric emissions, accounting for flight profiles and all major fuel types in active use (solid, kerosene, cryogenic and hypergolic). In 2019, stratospheric (15–50 km) rocket launch emissions were 5.82 Gg , 6.38 Gg O, 0.28 Gg black carbon, 0.22 Gg nitrogen oxides, 0.50 Gg reactive chlorine and 0.91 Gg particulate alumina. The geographic locations of launch sites are preserved in the inventory, which covers all active launch sites in 2019. We also report the emissions data from contemporary vehicles that were not launched in 2019, so that users have freedom to construct their own launch activity scenarios. A subset of the inventory—stratospheric emissions for successful launches in 2019—is freely available and formatted for direct use in global chemistry‐climate or Earth system models.

Aluminum particles as anode material for lithium ion batteries: effect of particle sizes on the electrochemical behaviours

This study presents a preliminary investigation on using pristine aluminum particles as anodes for lithium-ion battery. The microstructural characteristics of aluminum particle samples with sizes from 100 nm (0.1 μm) to 70 µm were analyzed by the SEM and XRD methods. The electrochemical behaviors of the aluminum particles were examined by the cyclic voltammetry (CV) and galvanostatic charge/discharge (GCD) measurements. The obtained results demonstrated the distinct lithiation/delithiation features of the aluminum electrodes at the potential couple of around 0.25 V/0.50 V vs. Li/Li+. Moreover, the GCD results also revealed the strong impact of the particle size on the initial capacity and galvanostatic discharge/charge potential profiles of electrode samples. However, aluminum electrodes with the large-sized particles showed dramatical capacity decay after certain cycles, and stabilized at around the specific capacity of 50 mAh g-1 and exhibited capacitive charge/discharge behavior. In contrast, the nano-sized particles aluminum electrodes possessed stable electrochemical performance upon cycling, but with low initial capacities. The results in this work will enrich the knowledge of the aluminum-based anode for LIBs in future works.

Extraordinary 99Mo adsorption: utilizing spray-dried mesoporous alumina for clinical-grade generator development

Abstract Mesoporous alumina spherical particles, synthesized via spray-drying with the self-assembly of EOnPOmEOn, have been utilized for the development of clinical-grade molybdenum-99/technetium-99 m (99Mo/99mTc) generators. When evaluated as molybdenum (Mo) adsorbents, the mesoporous alumina spherical particles are useful for effective adsorption of Mo ions rather than commercially available particulate alumina. The effects of surfactant removal methods on the Mo adsorption property are also systematically investigated using the batch method. Batch adsorption studies reveal practical adsorption capacities ranging from 45.9 to 91.2 mg Mo g−1 in a Mo solution (1000 mg Mo L−1) at pH 3. The experimental results indicate the following trend in Mo adsorption capacity: solvent extraction >calcination (400 °C and 800 °C) >commercially available alumina (Medical Al2O3 used as is). To explore the feasibility of developing a clinical-scale generator, a novel tandem column generator concept is employed. Using the spray-dried and extracted mesoporous alumina, 99mTc eluted from the generator exhibits high radionuclidic, radiochemical, and chemical purity, making it suitable for the preparation of 99mTc-labeled radiopharmaceuticals.