Formation Of Submicron Particles Research Articles

Diblock Copolymer Stabilized Liquid Metal Nanoparticles: Particle Settling Behavior and Application to 3D Printing.

Eutectic gallium indium (EGaIn) is a liquid metal with promising applications due to its favorable thermal and electrical conductivity, low viscosity, and metallic nature. For applications, including imaging, catalysis, and nanomedicine, stable EGaIn particles with submicron diameters are required. However, the low viscosity and high density of EGaIn have typically precluded the formation of stable submicron particles due to rapid EGaIn droplet coalescence. In this work, we show that poly(acrylic acid)-block-poly(N,N'-dimethylacrylamide) copolymers are able to effectively stabilize EGaIn nanodroplets formed upon ultrasonication, where the poly(acrylic acid) block anchors the polymer to the EGaIn surface and the poly(N,N'-dimethylacrylamide) block provides colloidal stability to the particles in solution. Although the high density of EGaIn causes rapid particle settling, the behavior is predictable, which allows the average particle size to be controlled through centrifugation. We demonstrate that stable EGaIn particles with sizes on the order of 50-100 nm and narrow particle size distributions can be easily obtained using this method and further used in photopolymer resins to prepare 3D printed EGaIn-polymer hybrid materials. The predictable sizes and high stability of these EGaIn nanoparticles should allow further applications in soft-electronics, nanomedicine, catalysis, and other nanotechnology.

Evaluating the Combined Impact of Temperature and Application of Interfacial Dilatational Stresses on Surface-mediated Protein Particle Formation in Monoclonal Antibody Formulations

Formation of submicron and subvisible protein particles (0.1–100 μm) present a major obstacle during processing and storage of therapeutic proteins. While protein aggregation resulting in particle formation is well-understood in bulk solution, the mechanisms of aggregation due to interfacial stresses is less understood. Particularly, in this study, we focus on understanding the combined effect of temperature and application of interfacial dilatational stresses, on interface-induced protein particle formation, using two industrially relevant monoclonal antibodies (mAbs). The surface activity of Molecule C (MC) and Molecule B (MB) were measured at room temperature (RT) and 4 °C in the absence and presence of interfacial dilatation stress using a Langmuir trough. These results were correlated with Micro-flow imaging (MFI) to characterize formation of subvisible protein particles at the interface and in the bulk solution. Our results show that the surface activity for both proteins is temperature dependent. However, the extent of the impact of temperature on the mechanical properties of the monomolecular protein films when subjected to dilatational stresses is protein dependent. Protein particle analysis provided evidence that protein particles formed in bulk solution originate at the interface and are dependent on both application of thermal stresses and interfacial dilatational stresses. In the absence of any interfacial stresses, more and larger protein particles were formed at the interface at RT than at 4 °C. When mAb formulations are subjected to interfacial dilatational stresses, protein particle formation in bulk solution was found to be temperature dependent. Together our results validate that mAb solutions maintained at 4 °C can lower the surface activity of proteins and reduce their tendency to form interface-induced protein particles both in the absence and presence of interfacial dilatational stresses.

The characteristics of particulate matter and optical properties of Brown carbon in air lean condition related to residential coal combustion

Severe haze in Beijing during February of 2020, corresponding to the pandemics of Covid-19, was ascribed to residential coal combustion, which is always air lean or of oxygen deficiency, for household heating in the rural areas around Beijing. In this study, a drop-tube furnace combustion system was employed, where five types of representative coal were burned under the conditions of three respective temperatures and an oxygen-deficient combustion condition to simulate different residential coal combustion regimes. The on-line number concentration distribution of particulate matters in flue gas emitted was obtained. By size-segregated particulate matters of PM1, PM2.5 and PM10 collected in a three-stage sampler during various coal burning, the mass of organic carbon (OC) and elemental carbon (EC) and optical properties of light-absorbing organic carbonaceous aerosol were measured extensively. The results indicated that high temperature encouraged the formation of sub-micron and ultra-micron particles. It was found that coal types had a great impact on the formation of EC aerosols, that is, the mass of EC decreased with increasing geological maturity. Besides, the formation of EC was also affected by temperature, that is, the lower the temperature was, the more EC components were generated. The optical properties of the aerosol particle extracted by methanol from PM1, PM2.5, and PM10 were measured and explored. The high values of absorption Ångström exponent (AAE) and mass absorption efficiency at the wavelength of 365 nm (MAE365) indicated the high wavelength-dependence characteristics and strong light absorbing abilities of brown carbon (BrC) from residential coal burning. AAE values from 1200 °C combustion emissions was observed to be diminishing with increasing fixed carbon to volatile matter ratio (FC/VM) and decreasing OC/(OC + EC). In addition, MAE365 values from low-temperature combustion were higher. These findings help us better understand the role that household coal burning plays in global BrC emission and its harm on the environment and human health.

Enhanced resistance to liquation cracking during fusion welding of cast magnesium alloys: Microstructure tailoring via friction stir processing pre-weld treatment

Magnesium alloys provide critical opportunities for energy and lightweight-materials challenges. The alloy design approach based on utilizing the second phase strengthening mechanism plays an essential role in producing low-density high strength Mg-based alloys. However, the second phase in the microstructure (e.g., Mg17Al12 phase in Mg–Al–Zn alloys) can deleteriously affect the weldability of the metallic materials by promoting the liquation and liquation cracking during fusion welding. The lack of sufficient weldability of Mg-based alloys is a crucial barrier to their potential use in safety-critical applications. In this paper, it is shown that the severe plastic deformation induced by friction stir processing, as an effective pathway to microstructure refinement, before fusion welding enables tailoring the initial microstructure of an Mg–Al–Zn cast alloy for enhancing its resistance to liquation cracking. The formation of ultra-fine sub-micron Mg17Al12 particles in friction stir treated base metal translates the liquation mechanism from sub-solvus constitutional liquation to super-solvus melting alloy, reducing the size of susceptible partial liquation zone to cracking. Moreover, the higher grain boundary density induced by dynamic recrystallization phenomena during friction stir processing can enhance the resistance to liquation cracking of the alloy. It is shown that this pre-welding strategy enables a significant enhancement in the weld mechanical properties compared to the conventionally produced welds. The joint efficiency, defined as the ratio of the joint tensile strength to the as-cast material tensile strength, was changed from 0.74 in case of welds made on cast base metal to 1.4 in case of welds made on friction stir processed base metal. This simple modification to the fusion welding process can be used as a practical pathway to enhance the weldability of liquation-sensitive second phase-strengthened alloys.

Modeling of the submicron particles formation and initial layer ash deposition during high temperature oxy-coal combustion

The future use of coal as a fuel for power generation in the US depends on the availability of financially viable technologies for capture and storage of CO2 emissions from power plants. Key second-generation candidates for CO2 capture include high temperature and pressurized oxy-firing of coal, which has the potential to increase efficiency, lower capital costs, avoid air ingress and reduce oxygen requirements. However, unquantified challenges, such as flame behavior, heat transfer, ash transformation, ash deposition and char oxidation, still exist for those technologies. This study specifically focuses on the formation of submicron particles and initial layer ash deposition during high temperature oxy-coal combustion. Previous work has shown that the initial layer deposits are mainly formed of submicron size ash aerosols transported by thermophoresis. Unfortunately, the importance of submicron particle deposition has not received much attention, probably due to the insignificant deposit mass and difficulty in prediction of the submicron particles formation. In this work, models including mineral matter vaporization model, scavenging model and deposition model are developed and applied into a three-dimensional CFD framework to predict the submicron particles formation and subsequent initial layer deposits formation. The model results are comparable to experimental data. The merits of this work are that it has led to the development of a novel approach to predict both submicron particle formation and initial layer ash deposition during oxy-coal combustion.

Rutin-containing chitosan films produced using in situ mechanoactivated precipitation process

In this article, we examined a new environmentally friendly process of introducing a hardly soluble active additive into chitosan edible films using the example of rutin, which has antioxidant and nutraceutical effects. The process is based on the formation of submicron particles of rutin in the chitosan matrix, during the short-term (10 s) mechanical activation of mixed aqueous solutions in a metastable state using a rotor-stator device. It is shown that mechanical activation accelerates the nucleation of rutin and prevents aggregation of the resulting particles due to embedding them in the polymer structure. Chitosan samples differing in molecular weight and deacetylation degree were used to form the films. It was found that the rutin particles size decreases with an increase in its concentration in supersaturated solutions, as well as with an increase in the chitosan solution viscosity. Rutin particles had a needle-like shape with a diameter of 0.40–0.75 μm and showed a reinforcing effect, increasing the tensile strength of chitosan films by 25–40%. Chitosan films containing rutin were smooth, uniformly yellow colored, and had lower water vapor permeability compared to films made of chitosan alone.

Mechanical properties and deformation mechanisms of a novel fine-grained Mg-Gd-Y-Ag-Zr-Ce alloy with high strength-ductility synergy

Grain boundary precipitation and segregation play an important role in determining mechanical properties of Mg alloys. In the present work, we studied work focuses on the strengthening and deformation mechanism of coarse-grained (CG) and fine-grained (FG) Mg-Gd-Y-Ag-Zr-Ce alloy. The CG alloy is strengthened by means of age-strengthening with the formation of both basal plate γ′′ and prismatic plate β′ precipitates in the grain interior. While the strengthening of FC alloy is completed by intergranular alloying segregation and intragranular precipitates γ′′ and β′. The segregation of alloying elements at the grain boundary and formation of sub-micron particles can stabilize the grain boundary and suppress the intergranular deformation. Consequently, dislocations could be trapped near γ′′ and β′ precipitates in the grain interior. Unlike CG alloys, the FG alloys exhibit a heterogeneous transition from elastic to plastic deformation via the Lüders plateau. The rapid gliding dislocation multiplications and fine-grained size are necessary and sufficient conditions for the Lüders strains. Our work provides the insights on the evolution of fine-grained microstructure and helps for the design of Mg alloys with good mechanical properties.

Numerical simulation of submicron particles formation during the combustion of coals, taking into account coagulation and dust content of combustion products

Homogeneous-heterogeneous bulk condensation of potassium sulfate vapor has been numerically simulated in a dusty vapor-gas flow of coal combustion products upon their cooling along a technological path. A closed model that we have proposed for the formation of submicron particles in coal combustion products has been employed. Data on the concentration of particles formed at varied parameters of heterogeneous condensation sites have been obtained. Variations in the relative contributions of the homogeneous and heterogeneous mechanisms with variations in flow dustiness have been considered. Data on the influence of coagulation processes on the parameters of submicron particles resulting from coal combustion have been presented.

Crystal and Supramolecular Structure of Bacterial Cellulose Hydrolyzed by Cellobiohydrolase from Scytalidium Candidum 3C: A Basis for Development of Biodegradable Wound Dressings.

The crystal and supramolecular structure of the bacterial cellulose (BC) has been studied at different stages of cellobiohydrolase hydrolysis using various physical and microscopic methods. Enzymatic hydrolysis significantly affected the crystal and supramolecular structure of native BC, in which the 3D polymer network consisted of nanoribbons with a thickness T ≈ 8 nm and a width W ≈ 50 nm, and with a developed specific surface SBET ≈ 260 m2·g−1. Biodegradation for 24 h led to a ten percent decrease in the mean crystal size Dhkl of BC, to two-fold increase in the sizes of nanoribbons, and in the specific surface area SBET up to ≈ 100 m2·g−1. Atomic force and scanning electron microscopy images showed BC microstructure “loosening“after enzymatic treatment, as well as the formation and accumulation of submicron particles in the cells of the 3D polymer network. Experiments in vitro and in vivo did not reveal cytotoxic effect by the enzyme addition to BC dressings and showed a generally positive influence on the treatment of extensive III-degree burns, significantly accelerating wound healing in rats. Thus, in our opinion, the results obtained can serve as a basis for further development of effective biodegradable dressings for wound healing.

Strengthening and ductilization mechanisms of friction stir processed cast Mg–Al–Zn alloy

AZ91 alloy, the most widely used Mg casting alloy, exhibits low strength/ductility and weak energy absorption, which is a function of its large grain size and the presence of a coarse and continuous network of β-Mg17Al12 intermetallic compounds. This work demonstrated that friction stir processing (FSP) enables enhancement of strength and energy absorption capability of AZ91 alloy. The influence of FSP treatment on various potential strengthening mechanisms, including grain boundary, solid solution, and sub-micron particle strengthening mechanisms, was studied. It is identified that the grain boundary strengthening plays a significant contribution to the strength of the FSP treated AZ91. FSP treatment altered the failure mechanism of the alloy from brittle cleavage-dominant mode to ductile dimple-dominant mode, which can increase the potential of cast Mg alloys to use in the safety-critical application. The significant improvement in energy absorption capability is a function of grain refining and the formation of ultra-fine sub-micron Mg17Al12 particles. The trends in mechanical properties of AZ91 treated by various severe plastic deformation approaches are disused.

Theracurmin inhibits intestinal polyp development in Apc-mutant mice by inhibiting inflammation-related factors.

Colorectal cancer (CRC) is the second leading cause of cancer death worldwide. Therefore, it is important to establish useful methods for preventing CRC. One prevention strategy involves the use of cancer chemopreventive agents, including functional foods. We focused on the well‐known cancer chemopreventive agent curcumin, which is derived from turmeric. However, curcumin has the disadvantage of being poorly soluble in water due to its high hydrophobicity. To overcome this problem, the formation of submicron particles with surface controlled technology has been applied to curcumin to give it remarkably improved water solubility, and this derived compound is named Theracurmin. To date, the preventive effects of Theracurmin on hereditary intestinal carcinogenesis have not been elucidated. Thus, we used Apc‐mutant mice, a model of familial adenomatous polyposis, to evaluate the effects of Theracurmin. First, we showed that treatment with 10‐20 µM Theracurmin for 24 hours reduced nuclear factor‐κB (NF‐κB) transcriptional activity in human colon cancer DLD‐1 and HCT116 cells. However, treatment with curcumin mixed in water did not change the NF‐κB promoter transcriptional activity. As NF‐κB is a regulator of inflammation‐related factors, we next investigated the downstream targets of NF‐κB: monocyte chemoattractant protein‐1 (MCP‐1) and interleukin (IL)‐6. We found that treatment with 500 ppm Theracurmin for 8 weeks inhibited intestinal polyp development and suppressed MCP‐1 and IL‐6 mRNA expression levels in the parts of the intestine with polyps. This report provides a proof of concept for the ongoing Theracurmin human trial (J‐CAP‐C study).

Microstructure of Aged 238Pu-doped La-monazite Ceramic and Peculiarities of its X-ray Emission Spectra

AbstractNew data on microstructure of 16 years old (La, Pu)PO4 monazite ceramics doped with 8.1 wt% of 238Pu are presented. It is shown that the sample consists from at least two phases differing in La/Pu ratio and small precipitates of Pu-phosphate. Possible mechanisms of the compositional heterogeneity are discussed. Formation of Pu-containing rhabdophane after sample storage in air is observed. This phenomenon together with gradual mechanical destruction of the ceramic pellet formation of submicron particles will likely increase rate of radionuclides loss from the monazite-based waste form. X-ray emission lines produced by recoil uranium ions from Pu decay are analysed. It is suggested that careful examination of their relative intensities may provide important information about behaviour of "hot" recoils in nuclear waste forms.

Registration of the Emission of Submicron Particles of Rocks to Predict the Destruction of Underground Mine Workings at Rockburst-Hazardous Deposits

The results of studies of the conditions for the formation of submicron particles from the surface of the rock formation under the influence of external factors are presented. The deformation and destruction of the mass of rock formations under the conditions of anthropogenic activity under the influence of rock pressure and blasting are characterized by the origin and development of structural defects at various scale levels. A method for recording the emission of submicron particles is proposed to carry out experimental work forstudies of the process of disintegration and the formation of free particles. The results of laboratory studies of the stress-strain state of rock formation samples with a through cylindrical cavity under uniaxial compression, made on the basis of a physical model for the formation of submicron particles from the surface of the samples under study, are presented. The sizes and nature of changes in stress concentration zones and fracture under quasi-static uniaxial loading of specimens are determined. The loading limits have been established to ensure the transfer of rock formation samples to the pre-fracture state. The obtained results are necessary for the development of a fundamentally new method and hardware-technical base for recording dynamic forms of manifestation of rock pressure and prediction of rockbursts in the conduct of underground mining. The results of experimental-industrial tests of the method for determining the stress-strain state of a specific section of a rock formation massif based on the phenomenon of submicron particle emission are presented.

Turmeric extract-loaded polyvinylpyrrolidone spherical submicron particles produced using electrohydrodynamic atomization: their physico-chemical properties and antioxidant activity

We synthesized novel spherical submicron particles of turmeric extract (TUR)-loaded polyvinylpyrrolidone (PVP) using the electrohydrodynamic atomization technique. The SEM images show the formation of spherical submicron particles for the mass ratio of TUR and PVP ≥ 2/5. Their average particle diameter increases with the TUR mass increment, which is induced by the conductivity, viscosity, and surface tension decrements of precursor solutions. Furthermore, the flow rate (Q) and conductivity (σ)-dependent average particle diameter (D) is in line with the particle diameter universal control given by log(D) = 0.320 log (Q/σ) − 1.135. From the FTIR spectra, the submicron particles clarify the intermolecular modes of PVP and TUR consisting of the vibration and the stretching modes at the high and low wavenumbers, respectively. Notably, the mass ratio of PVP and TUR modifies hydroxyl vibration modes. The XRD patterns show the dominant curcumin polycrystallines in the TUR particles, which are not observed in the PVP-TUR submicron particles. This result indicates the structural deformation of TUR between PVP bundles. From DSC measurements, the glass transition of PVP-TUR submicron particles (54.3 °C) is between that of PVP and TUR, agreeing the Gordon–Taylor formulation. Their melting point (166.4 °C) is lower than those of PVP and TUR, indicating the Schröder–van Laar relation. The relative mass changes of PVP-TUR submicron particles are higher than that of both PVP and TUR. Then, IC50 of the PVP-TUR submicron particles linearly decreases from (16.4 ± 3.9) to (10.5 ± 2.9) μg ml−1 with the TUR mass increment, implying the antioxidant activity enhancement with increasing the TUR mass.

The Effect of Dustiness of Combustion Products and Coagulation Processes on the Parameters of Submicron Particles Resulting from Coal Burning

Homogeneous–heterogeneous bulk condensation of potassium sulfate vapor has been numerically simulated in a dusty vapor–gas flow of coal combustion products upon their cooling along a technological path. A closed model that we have proposed for the formation of submicron particles in coal combustion products has been employed. Data have been obtained on the concentration and size distribution of particles formed at varied parameters of heterogeneous condensation sites and rates of variations in the temperature of the flow. Variations in the relative contributions of the homogeneous and heterogeneous mechanisms with variations in flow dustiness have been considered. A criterion enabling one to judge the effect of flow dustiness on the bulk condensation process has been proposed. This criterion takes into account both dust parameters and rate of temperature variations in a condensation zone. Data have been presented on the influence of coagulation processes on the parameters of submicron particles resulting from coal combustion.

Registration of Submicron Particle Emission for Rock Burst Prediction

In recent years the research into the processes of deformation and disintegration of materials at a submicron level has acquired greater importance for different areas of science. Mineral mining at different stages of production is associated with the formation of particles differing in size, including a submicron size range that has a negative environmental effect. However, as it has been proved by laboratory research practice, this effect can be used for rock stress-strained state monitoring both under quasi-static and dynamic types of load. In this work the emphasis is made on the fact that the formation of submicron particles at mechanical loading of rock can be used for its geotechnical monitoring. A new method has been developed for the assessment of the variation of a rock sample stress-strained state implying the registration of the formation of submicron particles from its surface under uniaxial compression. The research results are of scientific and practical interest for solid body disintegration, for rock in particular, and can be used for the development of a new method of virgin rock stress-strained monitoring, registration of dynamic forms of rock pressure occurrence to predict rock burst.

Spatiotemporal Variation in Composition of Submicron Particles in Santiago Metropolitan Region, Chile

The chemical composition of submicron particles (aerodynamic diameter Da < 1.0 μm) was investigated at three locations in the Santiago Metropolitan Region (SMR), Chile. Measurements campaigns were conducted in winter and spring 2016, at representative sites of a rural, urban and urban receptor environment. Instrumentation consisted of an optical analyzer to determine Black Carbon (BC) and the Aerosol Chemical Speciation Monitor (ACSM) to measure concentrations of particulate chloride (Cl-), nitrate (NO3-), sulfate (SO42-), ammonium (NH4+) and non-refractory carbonaceous species (organics). Complementary data, such as ozone concentration and meteorological parameters were obtained from the public air quality network. Results showed that in both the winter and spring seasons the organics predominated in the mass of submicron particles. This fraction was followed in decreasing order by NO3-, NH4+, BC, SO42- and Cl-. The highest average organics concentrations were measured in winter at the urban (32.2 µg m–3) and urban receptor sites (20.1 µg m–3). In winter, average concentrations of both NO3- and NH4+ were higher at the urban receptor site (12.3 and 4.5 µg m–3, respectively) when compared to the urban site (6.4 and 3.1 µg m–3, respectively). In general, all the measured species were present in higher concentrations during winter, excepting SO42-, which was the only one that increased during spring. The transition towards spring was also associated with an acidification of the aerosol at the rural and urban receptor site, while at the urban site the aerosol was observed alkaline. The highest average ozone concentration during both the winter and spring seasons were recorded at the urban receptor site (7.2 and 24.0 ppb, respectively). The study reports data showing that the atmosphere in the SRM has a considerable load of particulate organic compounds, NO3- and NH4+, which are in higher concentrations at urban sites during the winter season. Based on wind patterns and the hourly profiles of chemical species, the study suggests that during daytime the polluted air masses from the urban center can move to the northeast part of the region (namely urban receptor site) leading to the formation of submicron particles as well as photochemical ozone.

Aerosol-assisted synthesis of submicron particles at room temperature using ultra-fine liquid atomization

Aerosol-assisted particle technologies are common in commercial atomizing devices for producing micron-sized droplets, which upon evaporation of solvent typically yield particles in the micron to submicron range obtained from a process of droplet-to-particle conversion. In this paper, we demonstrate a technology that allows room-temperature manufacturing of particles O(100–500) nm in diameter by generating and drying of submicron droplet aerosols. As measured for water atomization, the produced droplets of O(200) nm in mean diameter are an order of magnitude smaller than 3–5 µm water droplets usually obtained from commercial atomizers and nebulizers. This reduction in droplet size promotes evaporation of solvent around two orders of magnitude faster than for the droplets produced by conventional atomization devices. Such rapid solvent evaporation enables formation of submicron particles even in the limit of room temperature drying conditions in a compact laboratory-scale setup, as we demonstrate in this study for sodium chloride and silica and titania xerogel particles. Ultra-fine diameters of the generated droplets enable the usage of more concentrated precursor solutions, e.g. ten or even one hundred times, to obtain the same final particle size as conventional aerosol-assisted setups. Based on the experimental study, we establish mathematical expressions correlating the mean particle size and production capacity with solute concentration in the precursor, physical properties of the solution and the atomizing air pressure. Finally, we compare and demonstrate the advantages of the developed system over the existing aerosol-assisted processes in terms of smaller particle size, larger overall and specific production capacities, and higher estimated energy efficiency. The results suggest that this economical and scalable method can be utilized for aerosol-assisted submicron particle synthesis in different applications.

Design of Pyrene-Fatty Acid Conjugates for Real-Time Monitoring of Drug Delivery and Controllability of Drug Release.

Fluorescence probes are usually employed to analyze pharmacokinetics of drug carriers; however, this method using usual probes is not suitable to monitor drug carriers in detail because fluorescence spectra do not change by the disruption of drug carriers. In this study, pyrene–fatty acid conjugates were investigated as probes to monitor the state of drug carriers in real time. 1-Pyrenemethanol was conjugated with fatty acids, such as lauric acid, stearic acid, and behenic acid, and the conjugates were stirred in ethanol, resulting in the formation of submicron particles; these particles exhibited excimer emission. When J774.1 and Colon 26 cells were treated with these particles, the associated fluorescence spectra shifted from excimer emission to monomer emission. Moreover, the degree of change was controlled by the type of fatty acid. These results support the design of drug carriers that can be used to monitor pharmacokinetics in real time and to control the disruption time.

Particle Breakage Kinetics and Mechanisms in Attrition-Enhanced Deracemization

In this study, we report on experiments designed to deconvolute the particle breakage kinetics and mechanism from the parallel phenomena (growth-dissolution, agglomeration) in attrition-enhanced deracemization processes. Through such experiments, we derived the specific breakage rates and cumulative breakage distribution functions for three grinding methods typically used in deracemization experiments: (a) bead grinding, (b) ultrasound grinding, and (c) the combination of bead and ultrasound grinding. Subsequently, we tested these methods on their ability to induce deracemization. We show that in the conventional bead grinding process, breakage occurs mostly by fracture. This results in slow deracemization rates due to the delayed formation of submicron particles that are essential to the process. Conversely, ultrasound grinding very efficiently breaks particles by abrasion. This leads to fast generation of an abundance of submicron fragments resulting in fast deracemization. However, using ultrasound, la...