Composite Particles Research Articles

Application of iron oxide and its composites containing carbon nanoparticles to the solution of environmental problems

AbstractThe radioactive materials and the secondary waste after a nuclear power plant accident pose a big environmental problem. The nontoxic iron oxide and iron oxyhydroxide, and their composites with carbon materials were applied to solve the problem. Coal oxide produced by modified Brodie method using coal, NaOH, and γ-Fe2O3 were treated by a hydrothermal process. When the diluted dispersion mixture was treated with SrCl2, the composite particles were attracted to a magnet. On the other hand, the composite without SrCl2 was not attracted. This means only the SrCl2-adsorbed composite can be recovered by a magnet. Hematite doped with various amounts of Nb was synthesized. Its catalytic activities for photo-Fenton reaction were investigated for degradation of methylene blue (MB) in the presence of H2O2 under visible light. Nb-doped hematite calcined at 600 ºC produced smaller particles and showed higher catalytic activity than those calcined at 700 ºC. It was shown that the sample with higher Nb doping showed a better catalytic activity, i.e., the sample with 40 atomic percent of Nb calcined at 600 ºC has the highest catalytic activity. The hematite with 7.4 atomic percent of Nb calcined at 600 ºC showed unique characteristics since it has rapid decomposition rate of MB as well as ferrimagnetic-like characteristics, which makes it separable by a magnet. The polymorphism of iron(III) oxyhydroxide was controlled by adding acetic acid, ethylenediamine, and citric acid. The lepidocrocite obtained by adding the additive of citric acid resulted in the presence of citric acid in the particles and revealed a large specific surface area and negative Zeta potential, which showed an extremely high catalytic activity of MB decomposition for photo-Fenton reaction.

Observing super-coarse carbonaceous aerosol particles containing chloride in a tropical savanna climate at an agro-forest site in Thailand.

Coarse aerosol particles containing chloride in tropical forests are significant for understanding biogeochemical cycles and atmospheric processes, with implications for environmental health and climate change mitigation. This study explored the sources of super-coarse carbonaceous aerosol particles containing chloride in a tropical savanna climate. Aerosol samples were collected from an agro-forest site in Thailand during the dry season and analyzed using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and Fourier-transform infrared (FTIR) spectroscopy. By examining the morphology and elemental compositions of individual aerosol particles, along with employing Positive Matrix Factorization (PMF) and backward trajectory analysis, potential sources were identified. The findings revealed two primary sources for the super-coarse aerosol particles: a mixture of biomass burning smoke and inorganic salts (likely from saline soil and sea salt), as well as halophilic fungal spores. FTIR analysis indicated the presence of compounds linked to biomass burning and clay minerals, influenced by prevailing northeast and southeast winds. Recommendations for future research include continued monitoring, correlation with meteorological parameters, and the application of transmission electron microscopy (TEM) for more detailed visualization and confirmation of aerosol sources.

Analyzing Morphology and Composition of Coarse Aerosol Particles in Bangkok, Thailand: Implications to Sources and Impacts of Aged Aerosols on Ecosystem Health and Climate Dynamics

AbstractDuring dry seasons, elevated aerosol levels across Thailand pose nationwide problems. Understanding and addressing this issue is challenging due to the dynamic nature of aerosol modification and generation during transport. This study investigates the morphology and elemental compositions of coarse aerosol particles in Bangkok, Thailand, during the dry seasons of 2020/21. Through scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectrometry (EDS), the study reveals a complex mixture of anthropogenic, mineral, biogenic, and marine aerosols. Anthropogenic sources, including biomass burning, vehicular emissions, and industrial activities, contribute to carbonaceous particles like soot aggregates and tar balls. Mineral dust particles, predominantly calcium-rich and aluminosilicate, originate from various sources including construction, industry, and natural processes. Aging processes alter the composition and properties of both carbonaceous and mineral particles, influencing nutrient deposition, carbon sequestration, cloud condensation nuclei formation, and light scattering. These processes have multifaceted impacts on ecosystem health and climate dynamics, highlighting the need for further research and mitigation strategies to address the environmental consequences of aged aerosol particles in urban environments like Bangkok.

Taxon-specific contributions of microeukaryotes to biological carbon pump in the Oyashio region

Abstract Microeukaryotes are critical components of sinking particles contributing to carbon export from the surface to deep oceans. However, the knowledge of the sinking microeukaryotic communities and their dynamics is currently limited. In this study, we applied 18S rRNA gene metabarcoding to investigate the microeukaryotic communities in sinking and suspended particles distinguished by marine snow catchers (MSC) during spring in the Oyashio region. Sinking particles displayed distinct communities and lower diversity than suspended particles. The community compositions of the sinking particles varied with depth, suggesting that microeukaryotes were selectively disaggregated or decomposed during settling. Prymnesiophyceae and diatoms were effectively removed, as indicated by their decreased abundance in sinking particles at increasing depths. Conversely, Dinophyceae maintained a higher abundance in sinking particles across depths, indicating resistance to disaggregation and decomposition. Spirotrichea and heterotrophic Dinophyceae were enriched in sinking particles, while marine stramenopiles (MAST) groups were enriched in suspended particles. The heterotrophs in the deeper layers were mainly transported from the surface layers by increasing their relative abundance towards deep layers, indicating that they contributed to the transformation processes of sinking particles. Overall, our results demonstrate the functional differences among microeukaryotes in the biological carbon pump.

Application of Sound Waves During the Curing of an Acrylic Resin and Its Composites Based on Short Carbon Fibers and Carbon Nanofibers

Research into particulate polymer composites is of significant interest due to their potential for enhancing material properties, such as strength, thermal stability, and conductivity while maintaining low weight and cost. Among the various techniques for preparing particle-based composites, ultrasonic wave stimulation is one of the principal laboratory-scale methods for enhancing the dispersion of the discontinuous phase. Nevertheless, there is a scarcity of empirical evidence to substantiate the impact of stimulating materials with natural sound frequencies within the acoustic spectrum, ranging from 20 Hz to 20 kHz, during their formation process. The present work investigates the effect of acoustic stimuli with frequencies of 56, 111, and 180 Hz on the properties of an acrylic-based polymer and its discontinuous carbon-based composites. The results indicated that the stimulus frequency affects the cure time of the studied systems, with a notable reduction of 31% and 21% in the cure times of the neat polymer and carbon-nanofiber-based composites, respectively, after applying a frequency of 180 Hz. Additionally, the higher stimulation frequencies reduced porosity in the samples, increased the degree of dispersion of the discontinuous phase, and altered the composite materials’ thermal, optical, and electrical behavior.

Combustion Characteristics and Performance of Nanoflower Structure AlB2@AP Energetic Composites

ABSTRACT Boron-based solids have garnered significant attention due to their high calorific value. However, during combustion, the formation of boron oxide (B₂O₃) on the surface hinders the interaction between the oxidizing components and the internal active boron (B), thereby limiting its reactivity and combustion efficiency. Modifying boron-based solids represents an effective strategy for overcoming the limitations associated with fuel energy release efficiency. In this study, a shell-structured AlB₂@AP composite was designed and fabricated utilizing etching and recrystallization methods. The structure comprises AlB₂ as the core, B as the middle shell, and AP as the embedded outer shell. The key strategy involves employing an etching process to augment the reactive surface area of boron on the aluminum diboride surface, while also coating it with ammonium perchlorate (AP) to enhance the composite particles. This innovative approach demonstrates that the etching method can effectively utilize the boron present in AlB₂. The composite particles were characterized and analyzed for morphology employing a scanning electron microscope and X-ray techniques. Thermal analysis indicated that the decomposition stage of AP facilitated the oxidation of etched AlB₂, moreover, as the AP coating content increased, the temperature at which vigorous reactions initiated occurred earlier. In combustion experiments, the maximum combustion temperatures of AlB₂@10AP, AlB₂@20AP, and AlB₂@30AP increased by 36.4%, 15.1%, and 3.8%, respectively. The combustion formulation prepared with elemental boron exhibited different characteristics. The average combustion temperatures increased by 33.1%, 23.4%, and 14.4%, respectively. The combustion durations were reduced by 60.8%, 33.7%, and 31.7%, respectively. AlB2@AP is anticipated to further enhance its applications in propellants, explosives, and pyrotechnics.

An organic-inorganic dual network built in fast-growing wood veneers to improve the flame retardant and mechanical properties of plywood

Fast-growing wood is widely used in plywood production due to its short growth cycle and low cost. However, its loose fiber structure, inferior material quality, and high flammability significantly limit the application range of plywood products and hinder high-value utilization. This paper reports a simple method for modifying fast-growing wood veneers. We modified phenolic resin with Mg(OH)₂@nano-silica composite particles and impregnated it into the veneers, constructing an organic-inorganic hybrid dual-network structure on both the surface and interior of the veneers. The plywood prepared from the modified veneers exhibited a bending strength of 115.6 MPa, a modulus of elasticity of 9.7 GPa, and a wet shear strength of 2.1 MPa, representing increases of 86.1%, 47.0%, and 90.9%, respectively, compared to plywood made from unmodified veneers. Additionally, the peak heat release rate decreased by 15.3%, and the ignition time was extended to 26 seconds. The uniformly distributed inorganic network effectively mitigated stress concentration and, together with the phenolic resin, formed an efficient thermal insulation layer, enhancing the flame retardancy of the material. This study offers a simple and effective treatment method for reinforcing fast-growing wood veneers, promoting the use of fast-growing wood in high-performance applications.

Composition-optimized NiGa-LDH on MOF-derived and cobalt-nanoparticles-embedded carbon flakes for enhanced potassium-ion storage

Layered double hydroxides (LDHs), renowned for their distinct nanostructures, efficient ion channels, and high specific capacitance, are promising electrode materials for supercapacitors (SCs). However, commercial applications remain limited due to constraints in the rate capabilities and cycling. The synergistic effects of the composites can be leveraged by pairing LDHs with carbon materials to enhance the conductivity for better SC characteristics. Herein, flaky Zeolitic Imidazolate Framework(ZIF)-67 is deposited on carbon cloth and calcined to produce the MOF-derived composite of carbon nanosheet-embedded nano-cobalt particles (CPEC) on the surface of the carbon cloth. Afterward, NiGa-LDH with a controllable Ni to Ga ratio is synthesized on the CPEC to form a flower-like hierarchical nanostructure NiGa-LDH/CPEC@CC. Co nanoparticles act as nucleation sites for cohesive formation within the carbon cloth framework. Ni2Ga1-LDH/CPEC@CC has the best properties, such as a specific capacitance of 729.6F g−1 at 1 mA cm−2 and 97.3 % capacitance retention at 2 mA cm−2. The asymmetric supercapacitor (ASC) consisting of Ni2Ga1-LDH/CPEC@CC//AC has an excellent energy density of 83.96 Wh kg−1 with a power density of 80 W kg−1. Density-functional theory (DFT) calculations of Ni2Ga1-LDH/CPEC@CC affirm a potassium ion adsorption energy of −2.127 eV and density of state (DOS) near the Fermi level. The study imparts theoretical and technical knowledge about the design of complex nanostructures from MOF precursors.

Composition and Effects of Aerosol Particles Deposited on Urban Plant Leaves in Terrestrial and Aquatic Habitats

Plants play a vital role in mitigating aerosol particles and improving air quality. This study investigated the composition characteristics and potential effects of particles retained on the leaf surfaces of two amphibious plants (i.e., Alternanthera philoxeroides and Hydrocotyle vulgaris) in both terrestrial and aquatic habitats. The results show that plant habitats influenced the composition of aerosol particles retained on leaf surfaces. Specifically, plants in terrestrial habitats retained a higher mass concentration of coarse and large particles rich in inorganic Ca2+, accounting for over 70% of total ions, whereas plants in aquatic habitats retained a greater abundance of fine and secondary particles with high fractions of water-soluble NO3− and SO42−, taking up over 65% of total anions. Secondary particles deposited on the surfaces of plants in aquatic habitats tend to deliquesce and transform from the particle phase to the liquid phase. Terrestrial habitats facilitate the deposition of large particles. Additionally, particle accumulation on leaf surfaces adversely affected the stomatal conductance of plant leaves, leading to reductions in both the transpiration and photosynthetic rates. This study provides insights into the impact and role of plants from different habitats in mitigating urban particulate pollution.

Complex assessment of ambient particulate matter in a small settlement with coal-handling port

Relevance. Russian coal exports have been steadily increasing in recent years, and Far Eastern ports, originally not adapted to dusty cargoes, have switched to coal operations. Unoptimized coal handling leads to increased content of coal-containing particles in the air and to various environmental problems. Aim. To analyze the concentration of particulate matter in the air and the chemical composition of particles on the surface of conifer needles in the Posyet settlement (Primorsky Krai, Russia), where a large coal terminal operates. Materials and methods. The chemical composition was studied on the surface of conifer needles by X-ray fluorescence and in washout of conifer needle samples using Raman spectroscopy and energy dispersive analysis. Concentrations of particles with the diameter of 2.5 and 10 μm (PM2.5 and PM10, respectively) were measured using automatic monitoring stations. Results and conclusions. Chemical composition was dominated by mineral particles (calcite, silicates, etc.). However, the presence of coal particles (up to 8.3%) and metal particles was also observed. Mean concentrations of PM2.5 and PM10 were within the Russian and international health standards, but close to their upper limits. Concentrations of both measured particle fractions were highest during the winter months (as well as in March, which is traditionally a cold month in the Far East), followed by a gradual decrease. The study obtained new data on the annual variations of concentrations of PM2.5 and PM10, as well as on the basic composition of particles from the surface of woody vegetation (needles) as an indicator of the state of air pollution in this settlement.

Optimization of polishing fluid composition for single crystal silicon carbide by ultrasonic assisted chemical-mechanical polishing

Silicon carbide (SiC) is renowned for its exceptional hardness, thermal conductivity, chemical stability, and wear resistance. However, the existing process is difficult to meet the high standards of uniform corrosion in its polishing process and surface roughness and flatness after polishing, new polishing fluids and technique optimization are crucial for development. The study optimized and validated the composition of the polishing fluid used in ultrasonic-assisted chemical-mechanical polishing (UACMP). Abrasives significantly influenced the material removal rate (MRR) and surface roughness (Ra), contributing 67.63% and 56.43%, respectively. Organic bases and pH buffers significantly affected Ra, accounting for 19.66% and 21.44%, respectively. The optimum composition was determined, consisting of triethylamine (3wt%), potassium hydrogen phthalate (1wt%), a composite of silica and alumina abrasive particles (5wt%), and hydrogen peroxide (6wt%), which reduced the Ra from 95 nm to 3 nm. The MRR achieved 25.96 nm/min. In comparison to the 7 nm minimum roughness from the orthogonal test, the optimal scheme’s Ra was reduced by 57.14%, leading to a significant enhancement in overall surface quality. In this paper, a new type of additive is added to prepare the polishing liquid, which provides a new idea for the UACMP of SiC and has a great impact.

Phages ZC01 and ZC03 require type-IV pilus for Pseudomonas aeruginosa infection and have a potential for therapeutic applications.

There has been a growing interest in bacteriophages as therapeutic agents to treat multidrug-resistant bacterial infections. The present work aimed at expanding the microbiological and molecular characterization of lytic phages ZC01 and ZC03 and investigating their efficacy in the control of Pseudomonas aeruginosa infection in an invertebrate animal model. These two phages were previously isolated from composting using P. aeruginosa strain PA14 as the enrichment host and had their genomes sequenced. ZC01 and ZC03 present, respectively, siphovirus and podovirus morphotypes. ZC01 was recently classified into the genus Abidjanvirus, while ZC03 belongs to Zicotriavirus genus of the Schitoviridae N4-like viruses. Through proteomics analysis, we identified virion structural proteins of ZC01 and ZC03, including a large virion-associated RNA polymerase that is characteristic of N4-like viruses, some hypothetical proteins whose annotation should be changed to virion structural proteins and a putative peptidoglycan hydrolase. Phages ZC01 and ZC03 exhibit a limited yet distinct host range, with moderate to high efficiency of plating (EOP) values observed for a few P. aeruginosa clinical isolates. Phage susceptibility assays in PA14 mutant strains point to the type-IV pilus (T4P) as the primary receptor for phages ZC01 and ZC03, and the major pilin (PilAPA14) is the T4P component recognized by these phages. Moreover, both phages significantly increase survival of Galleria mellonella larvae infected with PA14 strain. Taken together, these results underpin the therapeutic potential of these phages to treat infections by P. aeruginosa and lay the groundwork for a more detailed investigation of phage-bacteria-specific recognition mechanisms.IMPORTANCEPhage therapy is gaining increasing interest in cases of difficult-to-treat bacterial human infections, such as carbapenem-resistant Pseudomonas aeruginosa. In this work, we investigated the molecular mechanism underlying the interaction of the lytic phages ZC01 and ZC03 with the highly virulent P. aeruginosa PA14 strain and their efficacy to treat PA14 infection in Galleria mellonella larvae, a commonly used invertebrate model for phage therapy. We depicted the protein composition of ZC01 and ZC03 viral particles and identified pilin A, the major component of type-4 pilus, as the receptor recognized by these phages. Our findings indicate that phages ZC01 and ZC03 may be further used for developing therapies to treat multidrug-resistant P. aeruginosa infections.

ZIF‐67 Derived Cobalt Catalysts for the Hydroformylation of Liquid Olefins

AbstractIn this work, we described a general monometallic cobalt heterogeneous catalyst for the hydroformylation of olefins, achieving good yields and recyclability up to five times with no loss in catalytic activity. These catalysts were prepared through the pyrolysis of the well‐defined metal–organic framework ZIF‐67. The addition of steam during the pyrolysis did not affect the final phase composition of the cobalt particles; nonetheless, it resulted in an increase of the cobalt particle size and the partial removal of the carbonaceous matrix. The materials were extensively characterized by several techniques, and it was observed that the N‐doped carbon matrix played a crucial role in terms of activity and stability. Different liquid olefins, including internal, terminal, and cyclic were successfully tested in our hydroformylation protocol. Aldehydes yields of 48%–77% for different liquid olefins were achieved with the optimal catalyst. No leaching of the active sites was observed over five catalytic cycles. The high stability of the catalyst is attributed to the presence of stabilizing nitrogen atoms bearing the cobalt sites.

Microstructure of confectionery masses revealed by cryo-planing

Here we present a novel, combined cryo-scanning electron microscopy (cryo-SEM) and confocal laser scanning microscopy (CLSM) method for imaging of chocolate confectionery product microstructures of several millimeters down to about 100 nm. The SEM part of the method is based on cryo-fixation, cryo-polishing, and scanning electron microscopy, at low vacuum and low temperature using the backscattered electron signal. Starting with cryo-fixation of the chocolate sample in a desired state (cooled, ambient, or melted), the sample is cryo-planed in a cryo-ultramicrotome. Once a polished cut is obtained, the sample is analyzed using a cryo-SEM technique, with the unusual combination of low temperature and low vacuum settings, without heavy metal coating. Imaging is done based on material density contrast. Elemental composition of particles is recorded by energy dispersive x-ray spectroscopy (EDS). The combination of imaging contrast and EDS allows identification and measurement of the four main constituents of chocolate (cocoa solids, fat, sugar, and milk solids). Finally, the same cryo-polished sample sections of solid chocolate products are analyzed using a CLSM imaging technique to reveal complementary microstructural details. An obvious application of the method could be the visualization and quantitative analysis of the size, shape, and composition of chocolate confectionery products.

Response tests on the effects of particle size of waste glass sand and glass powder on the mechanical and durability performance of concrete

To investigate the effect of waste glass material particle sizes on the mechanical and durability properties of concrete, a two-phase experimental approach was conducted. First, comprehensive tests were performed to examine the effects of glass sand and glass powder of different particle sizes on concrete performance. Subsequently, based on the experimental results, an orthogonal test was designed to optimize the replacement amounts of composite particle sizes. The results indicated that an appropriate amount of glass sand can enhance the mechanical properties and durability of concrete, while excessive amounts or larger particle sizes may have adverse effects. The pozzolanic effect of glass powder also contributes to performance improvement, but the replacement rate should be limited to 20%. Under composite particle size conditions, the compressive, tensile, and shear strengths of concrete increased by 35.56%, 21.74%, and 13.79%, respectively, while durability significantly improved, with water absorption reduced by 20.73% and chloride ion permeability decreased by 63.10%. At a total replacement rate of 20%, the optimal proportions were determined to be 2.86% for 0.6 mm glass sand, 1.43% for 1.18 mm glass sand, 8.57% for 50–60 μm glass powder, and 7.14% for 60–70 μm glass powder. The incorporation of composite particle sizes improved the microstructure of concrete, thereby enhancing its mechanical and durability properties.

Bio-optical variability of particulate matter in the Southern Ocean

The composition and size distribution of particles in the ocean control their optical (scattering and absorption) properties, as well as a range of biogeochemical and ecological processes. Therefore, they provide important information about the pelagic ocean ecosystem’s structure and functioning, which can be used to assess primary production, particle sinking, and carbon sequestration. Due to its harsh environment and remoteness, the particulate bio-optical properties of the Southern Ocean (SO) remain poorly observed and understood. Here, we combined field measurements from hydrographic casts from two research voyages and from autonomous profiling floats (BGC-Argo) to examine particulate bio-optical properties and relationships among several ecologically and optically important variables, namely the phytoplankton chlorophyll a concentration (Chl), the particulate absorption coefficient (ap), the particulate backscattering coefficient (bbp), and the particulate organic carbon (POC) concentration. In the clearest waters of the SO (Chl < 0.2 mg m−3), we found a significant contribution to absorption by non-algal particles (NAP) at 442 nm, which was up to 10 times greater than the absorption by phytoplankton. This makes the particulate bio-optical properties there remarkably different from typical oceanic case 1 water. A matchup analysis confirms the impact of this larger NAP absorption on the retrieval of Chl from satellite ocean colour observations. For waters with Chl > 0.2 mg m−3, no significant differences are observed between the SO and temperate waters. Our findings also demonstrate consistency in predicting phytoplankton carbon from either Chl or bbp, suggesting that both methods are applicable in the SO.

Photodegradation stability of marine coatings derived from PVC binder loaded with composite metal oxides particles

Photodegradation stability of marine coatings derived from PVC binder loaded with composite metal oxides particles

Solid, structured composite neutron detectors with high dynamic range capability

Neutron detectors are essential across disciplines such as fundamental science, nuclear security, safeguards, and civilian applications. While 3He-filled gas proportional counters have long been revered for their efficacy in detecting thermal neutrons and praised for their efficiency, neutron/gamma discrimination, and stability, the scarcity of 3He has spurred a search for alternatives. Here, we explore a solid structured scintillating particle composite (SPC) consisting of 6Li-containing scintillating glass particles within an acrylic matrix as a neutron detector for high dynamic range applications. We show for the first time that an SPC neutron detector can boast an intrinsic detection efficiency of 0.261% for pure 252Cf fission neutrons and an overall neutron detection efficiency of (0.546 ± 0.003)% at the Neutron Free-in-Air facility while being able to function in an intense gamma-ray environment. We also show that the SPC neutron detector supports fast neutron capture times and enables a dual-readout scheme that extends the detector dynamic range to high incident neutron fluxes. A scalable fabrication process allows for tailoring the SPC detector properties to the requirements of specific applications. Good agreement is found between the experimental results taken with a National Institute of Standards and Technology traceable 252Cf source and the coupled MCNP6 and optical-ray-tracing simulations.

How Porosity Influences the Heterogeneous Ice Nucleation Ability of Secondary Organic Aerosol Particles

AbstractDuring processing in deep convective cloud systems, highly viscous or glassy secondary organic aerosol (SOA) particles can develop a porous structure through a process known as atmospheric freeze‐drying. This structural modification may enhance their heterogeneous ice nucleation ability under cirrus conditions through the pore condensation and freezing mechanism. Pristine, compact SOA particles, on the other hand, are recommended to be treated as ice‐inactive in models. This recommendation also applies to internally mixed particles, where a coating layer of secondary organic matter (SOM) deactivates the intrinsic ice nucleation ability of the core, which may be a mineral dust grain. Ice cloud‐processing may also improve the ice nucleation ability of such a composite particle by inducing structural changes in the coating layer, which can release active sites on the mineral surface. In this work, we investigated the change in the ice nucleation ability of pure SOA particles from the ozonolysis of α‐pinene and two types of internally mixed particles (zeolite and coal fly ash particles coated with SOM) after being subjected to the atmospheric freeze‐drying process simulated in an expansion cloud chamber. For pure α‐pinene SOA, we found only a slight improvement in the ice nucleation ability of the ice cloud‐processed, porous particles compared to their pristine, compact counterparts at 221 and 217 K. In contrast, the zeolite and coal fly ash particles, which were initially deactivated by the organic coating, became significantly more ice‐active after atmospheric freeze‐drying, emphasizing that such composite particles cannot be excluded from model simulations of heterogeneous ice formation.

Cold-Atom Particle Collider

A major objective of the strong ongoing drive to realize quantum simulators of gauge theories is achieving the capability to probe collider-relevant physics on them. In this regard, a highly pertinent and sought-after application is the controlled collisions of elementary and composite particles, as well as the scattering processes in their wake. Here, we propose particle-collision experiments in a cold-atom quantum simulator for a 1+1D (one spatial and one temporal dimension) U(1) lattice gauge theory with a tunable topological θ term, where we demonstrate an experimentally feasible protocol to impart momenta to elementary (anti)particles and their meson composites. We numerically benchmark the collisions of moving wave packets for both elementary and composite particles, uncovering a plethora of rich phenomena, such as oscillatory string dynamics in the wake of elementary (anti)particle collisions due to confinement. We also probe string inversion and entropy production processes across Coleman’s phase transition through far-from-equilibrium quenches. We further demonstrate how collisions of composite particles unveil their internal structure. Our work paves the way towards the experimental investigation of collision dynamics in state-of-the-art quantum simulators of gauge theories, and sets the stage for microscopic understanding of collider-relevant physics in these platforms. Published by the American Physical Society 2024