FIB-SEM Images Research Articles

Curtaining artifacts generation on synthetic FIB-SEM data via Generative Adversarial Networks

FIB-SEM imaging stands out as an advanced method for capturing nanoscale structures. Throughout the image acquisition process, various artifacts emerge, including curtaining and charging artifacts. Effectively addressing these artifacts requires specialized algorithms tailored to their unique characteristics. Consequently, the development of algorithms demands simulated images used as benchmarks for validation. Simulating FIB-SEM images is a complex task, prompting the exploration of generative models as an alternative for simulation. We have adapted generative models to encompass curtaining artifacts, a feature challenging to replicate through conventional simulations. The resulting images demonstrate comparability with synthetically generated counterparts.

Unraveling the Impact of Boron Nitride and Silicon Nitride Nanoparticles on Thermoplastic Polyurethane Fibers and Mats for Advanced Heat Management.

The urgent challenges posed by the energy crisis, alongside the heat dissipation of advanced electronics, have embarked on a rising demand for the development of highly thermally conductive polymer composites. Electrospun composite mats, known for their flexibility, permeability, high concentration and orientational degree of conductive fillers, stand out as one of the prime candidates for addressing this need. This study explores the efficacy of boron nitride (BN) and its potential alternative, silicon nitride (SiN) nanoparticles, in enhancing the thermal performance of the electrospun composite thermoplastic polyurethane (TPU) fibers and mats. The 3D reconstructed models obtained from FIB-SEM imaging provided valuable insights into the morphology of the composite fibers, aiding the interpretation of the measured thermal performance through scanning thermal microscopy for the individual composite fibers and infrared thermography for the composite mats. Notably, we found that TPU-SiN fibers exhibit superior heat conduction compared to TPU-BN fibers, with up to a 6 °C higher surface temperature observed in mats coated on copper pipes. Our results underscore the crucial role of arrangement of nanoparticles and fiber morphology in improving heat conduction in the electrospun composites. Moreover, SiN nanoparticles are introduced as a more suitable filler for heat conduction enhancement of electrospun TPU fibers and mats, suggesting immense potential for smart textiles and thermal management applications.

Image quality evaluation for FIB-SEM images.

Focused ion beam scanning electron microscopy (FIB-SEM) tomography is a serial sectioning technique where an FIB mills off slices from the material sample that is being analysed. After every slicing, an SEM image is taken showing the newly exposed layer of the sample. By combining all slices in a stack, a 3D image of the material is generated. However, specific artefacts caused by the imaging technique distort the images, hampering the morphological analysis of the structure. Typical quality problems in microscopy imaging are noise and lack of contrast or focus. Moreover, specific artefacts are caused by the FIB milling, namely, curtaining and charging artefacts. We propose quality indices for the evaluation of the quality of FIB-SEM data sets. The indices are validated on real and experimental data of different structures andmaterials.

Direct visualization and 3D reconstruction of conductive filaments in aSiO2 material-based memristive device.

Observation of conductive filaments has greatly aided the development of theoretical models of memristive devices. In this work, we visualized and reconstructed the conductive filaments in a Cu/Cu-doped SiO2/W device employing a focused ion beam (FIB) as a milling technique. The SEM images taken from the device after 150 DC sweep cycles showed that Joule heat played a vital role in determining the morphology of a conductive filament, where the vaporization of the conductive filament resulted in the creation of defects, including particles, voids, and cavities. The competition between the formation and vaporization of conductive filaments generally induces a remarkable current fluctuation. Since Cu-doped SiO2 was utilized as the electrolyte, the vapors exfoliated adjacent single layers. FIB milling proceeded in top-down and front-back modes; thus, a 3D model of conductive filaments and defects was constructed according to a series of FIB-SEM images. This methodology is promising for a future failure analysis of memristive devices.

Development of MEAs Using Mesoporous Carbon Fibers as Cathode Carbon Supports

Introduction Mesoporous carbon (MC) has recently been paid more attention to as a carbon support for polymer electrolyte fuel cells (PEFCs), which are promising energy technologies for a future decarbonized society, since it is used in TOYOTA MIRAI. We have also been developing MC materials, whose diameter is slightly less than 10 nm, since 2006. More recently, we have developed MC fibers (MCFs) using an electrospinning method. Although MCF can form a sheet, it can be milled to powder. Comparing to our MC, MCF was found to be easily milled to smaller carbon particles. Then, we are interested in a correlation between IV performance and three dimensional structure of cathode layers made of different MC based powder. The aim of this study is to find important parameters to develop the cathode layer to achieve high IV performance. In this study, we synthesized MCF followed by ball-milling to the smaller carbon particles and evaluated the IV performance and structure of MCF based cathode layers. The detailed comparison to MC cathode layers1 was performed. Experimental MCFs were made by electrospinning of the precursor solution containing a surfactant (Pluronic F127) and carbon precursors (phloroglucinol dihydrate, formaldehyde, and triethyl orthoacetate) dissolved in the acid water/ethanol solution, and PVA solution. The obtained MCF precursor sheet was heated in the oven for polymerization of carbon precursors, and then heated up to 8 h by stepwise in the oven under the nitrogen atmosphere in order to decompose Pluronic F127 and carbonized precursors. MCF sheets were milled to small particles by hands and then zirconia balls at 450 rpm and 800 rpm. Pt nanoparticles were deposited on MCF powder by using Pt(acac)2 as a precursor. MEAs with 1cm2 electrodes were fabricated on the Nafion212 membrane. Prepared MCF based catalysts were used for the cathode, and 46.5% Pt/KB (TEC10E50E) was used for the anode. Results and discussion IV performance of MEAs with different cathodes, such as 46.5% Pt/KB (TEC10E50E), 33%Pt/MC, and 32%Pt/MCF, were evaluated and compared. When each overvoltage was evaluated separately, high ohmic overvoltage was seen for MEA with 33%Pt/MC. However, it was reduced for MEA with 32%Pt/MCF. When carbon particles size was compared between the two, MCF was found to be milled into much smaller particles as seen Figure 1. The resulting smaller particles most likely reduced the contact resistance between the particles.Diffusion overvoltage was found to be lowered when 33%Pt/MC and 32%Pt/MCF were used in the cathode. In order to find out a mechanism of the resulting low diffusion overvoltage, the cathode structure was three dimensionally evaluated using FIB-SEM and 3D imaging software. Relatively larger pores were seen in 33%Pt/MC and 32%Pt/MCF cathodes than in 46.5% Pt/KB (TEC10E50E) cathode. Such large pores or/and mesopores might be positively work for mass diffusion, but the mechanism for low diffusion overvoltage is still under the study.

Durability of Water Electrolysis Cells Against the Long-Term Voltage Fluctuation Simulating Wind Power

Introduction Water electrolysis is an important technology for efficiently combining the renewable energy with hydrogen energy. For directly using the renewable energy to produce hydrogen and oxygen through water electrolysis, the long-term durability against the voltage fluctuation of the renewable energy is necessary. We have particularly focused on the voltage fluctuation of the wind power. Typical 24-h wind power voltage fluctuations were obtained from one of three wind lenses of a 10-kW Muti-Lens Turbine® installed in Hibikinada, Japan, and applied to a single PEM water electrolysis cell after reducing the actual voltage to one-hundredth of the original value. When 20-d voltage fluctuations were applied, no degradation of the water electrolysis cell was observed if 1-h rest time was included after every 48-h voltage fluctuations for removing stagnated gases.Therefore, we have recently designed two types of voltage fluctuation protocols with different upper potential (2.0 V and 2.3 V) based on actual wind voltage fluctuations and evaluated durability of water electrolysis cells equivalent to 160 days.1 In both cases, reversible and irreversible current losses were observed. Reversible performance degradation was found to be most likely due to the gas stagnation and the reversible change of the oxidation state of iridium oxide catalysts. On the other hand, a few percent of the irreversible loss was found, which was mostly due to physical changes of the anode catalyst layer.In this study, to understand the irreversible loss more deeply, further long-term durability was evaluated and deterioration mechanisms were investigated. Experimental Water electrolytic cells were prepared by spray printing 46.3% Pt/KB and IrO2 for the cathode and the anode, respectively, on a Nafion 117 membrane. Voltage fluctuations with an upper limit of 2.3 V, shown in Fig. 1, were applied to a water electrolysis cell after accelerating the voltage fluctuation five times. Repeating the voltage fluctuation 228 times was defined as one set, corresponding to 48 h of actual operation. A total of 160 sets, corresponding to 320 d of actual operation, were performed in order to evaluate the durability of water electrolysis cells. The potential was applied to the anode, while maintaining the cathode at ~0 V.Electrochemical measurements of AC impedance and I-V performance were done at the beginning and after each set. Each overvoltage was separately analyzed. CV measurements of the anode side were also performed at the beginning and after 160 sets.For material characterizations, FIB-SEM observation followed by three-dimensional reconstruction were performed to evaluate the anode catalyst layer. Result and discussion A similar trend of decreasing and recovering the current to our previous study1 was confirmed in the extended voltage fluctuations. On the other hand, the recovery speed of the current was found to be slowed down. This may be related to increase in hydrophilicity of the IrO2 catalyst surface, which was highly oxidized by cycling to 2.3 V. Owing to increased hydrophilicity, pores of the catalyst layer were mostly filled with water and then the limited space was available for gas transfer. Although the oxidation state reversibly changed, its speed was probably slow.Regarding to the irreversible current loss, it was more pronounced. Figure 2 shows a cross-sectional image of the anode catalyst layer after the test equivalent to 320 d. An increase in the thickness of the anode, a part of which peeled off, was confirmed. This is most likely due to stagnated gas has increased the pressure within the anode catalyst layer. Since the gas stagnation is related to the initial pore structure of the anode catalyst layer, three-dimensional reconstruction of the anode structure using hundreds of FIB-SEM images was performed and analyzed in detail while comparing to the structure in our previous study. As a result, the water electrolysis cell used in this study had a relatively dense structure, which might be related to the amount of Nafion ionomer added in the anode catalyst layer, probably led to more gas stagnation, leading to an irreversible change of the anode structure. Reference (1) Y. Honsho et. al., J Power Sources 564, 232826, 2023. Figure 1

Understanding pore space and oil content of liquid-rich shale in the southern Bohai Sea, China

The commercial production of shale oil in onshore Bohai Bay Basin has become a reality, but the potential of offshore shale oil is still unclear. The Bohai Sea, the leading crude oil-producing area in China in 2022, has great potential of shale oil resources, but the shale properties have not been comprehensively studied. The southern Bohai Sea, including the Huanghekou and southwestern Bozhong Sags, was selected. The study was performed on three layers: the third member of Shahejie Formation, first and second members of Shahejie Formation (as a whole), and the third member of Dongying Formation. Twenty-one shale core samples from nine wells, for the first time, were analyzed for sedimentary structure, lithology, pore space, composition of the thermally hydrocarbons and oil content. The content of minerals, pore sizes, and composition of the thermally hydrocarbons were compared with those of shales from other regions of China. The potentially producible oil generated in the organic-rich laminae was found to be accumulated in the silt-grained laminae through micromigration. Mixed and siliceous shale were the main lithofacies. Mineral overgrowths and solid bitumen reduce the volume of former intergranular pores. Honeycomb-like OM pores in samples with higher maturity (Ro > 1.1%) substantially increased pore connectivity from FIB-SEM image datasets. The retained oil was mainly distributed in pores with widths larger than 4 nm. The composition of the thermally hydrocarbons in samples stored at ambient conditions was governed by the maturity and concentration of the OM. Light hydrocarbons, even gaseous hydrocarbons are still retained in the shale with lower maturity and higher TOC for strong sorption of OM. The oil content is 0.50–23.41 mg/g after Rock-Eval S1 correction, with an average of 6.27 mg/g. While average oil content is 1.38 mg/g without correction. Finally, the optimal production intervals for Well B4 and Well B8 were determined. This study provides data and suggestions for the exploration of shale oil resources in the southern Bohai Sea.

Discrete 3D modeling of porous-cracked ceramic at the microstructure scale

The porous-cracked microstructure of plasma sprayed ceramics coatings directly influences their macroscopic mechanical response.A 3D micromechanical model based on the discrete element method (DEM) is developed to reproduce their behavior. 3D observations are conducted with FIB-SEM nano-tomography and image analysis is used to extract and discretize the microstructure. A modeling strategy is developed to incorporate both pores and cracks into the model while preserving the computation performance. The lattice nature of DEM is used for the modeling of crack thickness that are smaller than the discrete element size. A method to compute the crack thickness from gray level images is proposed.Virtual quasi-static tests are performed on a sample of yttria-stabilized-zirconia. The results are in accordance with the literature data, such as the anisotropy and the non-linear behavior. The model is helpful to precisely investigate the role of the microscopic components, and micro-cracking on the macroscopic failure.

The Molecular Model of Organic Matter in Coal-Measure Shale: Structure Construction and Evaluation Based on Experimental Characterization

To investigate the molecular structure and micropore structure of organic matters in coal-measure shale, the black shale samples of the Shanxi formation were collected from Xishan Coalfield, Taiyuan, and a hybrid experimental–simulation method was used for realistic macromolecular models of organic matter (OM). Four experimental techniques were used to determine the structural information of OM, including elemental analysis, state 13C nuclear magnetic resonance (13CNMR), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR). With structural parameters, two-dimensional (2D) average molecular models of OM were established as C177H160O8N2S with a molar weight of 2474, which agreed well with the experimental 13C-NMR spectra. A realistic three-dimensional (3D) OM macromolecular model was also reconstructed, containing 20 2D molecules with a density of 1.41 g/cm3. To determine the connectivity and spatial disposition of the OM pores, focused ion beam microscope (FIB-SEM) and transmission electron micrographs (TEM) were utilized. The 3D OM pores models were developed. The results show that whether the OM pores varied from 20 to 350 nm as obtained from FIB-SEM images or less than 10 nm as observed in the TEM images, both were of poor connectivity. However, the ultra-micro pores from the 3D OM macromolecular model varied from 3Å to 10 Å and showed certain connectivity, which may be the main channel of diffusion. Furthermore, with the pressure increased, the methane adsorption capacity of the 3D OM model increased with a maximum value of 103 cm3/g at 7 MPa, indicating that OM pores less than 1 nm have a huge methane adsorption capacity. Therefore, our work provides an analysis method that is a powerful and superior tool in further research on gas migration.

A data-driven modeling approach to quantify morphology effects on transport properties in nanostructured NMC particles

We present a data-driven modeling approach to quantify morphology effects on transport properties in nanostructured materials. Our approach is based on the combination of stochastic modeling of the 3D nanostructure and numerical modeling of effective transport properties, which is used to investigate process-structure–property relationships of hierarchically structured cathode materials for lithium-ion batteries. We focus on nanostructured LiNi1/3Mn1/3Co1/3O2 (NMC) particles, the nanoporous morphology of which has a crucial impact on their effective transport properties (i.e, effective ionic and electric conductivity) and thus on the performance of the cell. First, we develop a parametric stochastic model for the 3D morphology of the nanostructured NMC particles based on excursion sets of so-called χ2-fields. This model, which has only two parameters, is then fitted to FIB-SEM image data of the NMC particles manufactured with different calcination temperatures and different particle sizes. This way it is possible to generate digital twins of the NMC particles. In a second step, measured 3D image data and corresponding digital twins are used as input for the numerical simulation of effective transport properties. Based on the results obtained by these simulations, we can quantify process-structure–property relationships. Overall, we present a methodological framework that allows for an efficient optimization of the fabrication process of nanostructured NMC particles.

Logistics of Bone Mineralization in the Chick Embryo Studied by 3D Cryo FIB-SEM Imaging.

During skeletal development, bone growth and mineralization require transport of substantial amounts of calcium, while maintaining very low concentration. How an organism overcomes this major logistical challenge remains mostly unexplained. To shed some light on the dynamics of this process, cryogenic focused ion beam-scanning electron microscopy (cryo-FIB/SEM) is used to image forming bone tissue at day 13 of a chick embryo femur. Both cells and matrix in 3D are visualized and observed as calcium-rich intracellular vesicular structures. Counting the number of these vesicles per unit volume and measuring their calcium content based on the electron back-scattering signal, the intracellular velocity at which these vesicles need to travel to transport all the calcium required for the mineral deposited in one day within the collagenous tissue can be estimated. This velocity at 0.27 µm s-1 is estimated, which is too large for a diffusion process and rather suggests active transport through the cellular network. It is concluded that calcium logistics is hierarchical and based on several transport mechanisms: first through the vasculature using calcium-binding proteins and the blood flow, then active transport over tens of micrometers through the network of osteoblasts and osteocytes, and finally diffusive transport over the last one or two microns.

Electric field distribution around asymmetric agglomerate model reconstructed from FIB–SEM images of epoxy nanocomposite

AbstractThis study focussed on determining the electric field distribution formed by asymmetric agglomerates in order to elucidate the mechanism by which large agglomerates reduce the dielectric breakdown strength of nanocomposites. Epoxy nanocomposite sample was prepared by adding 2.5 vol% of TiO2nanoparticles with a primary particle size ranging from 30 to 50 nm. The three‐dimensional (3D) structure of the epoxy nanocomposites with a thickness of 5 μm was analysed via focussed ion beam and scanning electron microscopy. The 3D reconstruction was performed using 250 observation images, and a 3D model of the particle in the observational range was obtained. The electric field distribution for the 3D model of the agglomerate with the largest size was determined using the finite element method. In addition, we constructed a calculation model that effectively accommodate changes in the direction of the applied electric field. Subsequently, we examined the changes in the maximum electric field intensity around the agglomerate.

Methods of enhanced FIB-SEM sample preparation and image acquisition.

The ability to view biomolecules in cells and measure changes in their structure, quantity, distribution, and interaction is fundamental to understanding biology. By coupling nano -scale resolution with meso and even macro scale volumes, the enhanced focused ion beam-scanning electron microscopy (FIB-SEM) pipeline has enabled numerous transformational discoveries in life science, many of which were major new landmarks in their fields. This pipeline consists of EM sample preparation, FIB-SEM sample preparation, FIB-SEM imaging, data alignment, and image analysis. While the EM sample preparation, data alignment, and image analysis are consistent with those from other volume Electron Microscopy (vEM) approaches, the enhanced FIB-SEM sample preparation and imaging are unique to the rest of comparable methods. We here illustrate the detailed methods of enhanced FIB-SEM sample preparation and image acquisition that have not been previously described. These methods can also be applied to the conventional FIB-SEM platforms for improved image acquisition quality and pipeline throughput.

En bloc preparation of Drosophila brains enables high-throughput FIB-SEM connectomics.

Deriving the detailed synaptic connections of an entire nervous system is the unrealized goal of the nascent field of connectomics. For the fruit fly Drosophila, in particular, we need to dissect the brain, connectives, and ventral nerve cord as a single continuous unit, fix and stain it, and undertake automated segmentation of neuron membranes. To achieve this, we designed a protocol using progressive lowering of temperature dehydration (PLT), a technique routinely used to preserve cellular structure and antigenicity. We combined PLT with low temperature en bloc staining (LTS) and recover fixed neurons as round profiles with darkly stained synapses, suitable for machine segmentation and automatic synapse detection. Here we report three different PLT-LTS methods designed to meet the requirements for FIB-SEM imaging of the Drosophila brain. These requirements include: good preservation of ultrastructural detail, high level of en bloc staining, artifact-free microdissection, and smooth hot-knife cutting to reduce the brain to dimensions suited to FIB-SEM. In addition to PLT-LTS, we designed a jig to microdissect and pre-fix the fly's delicate brain and central nervous system. Collectively these methods optimize morphological preservation, allow us to image the brain usually at 8 nm per voxel, and simultaneously speed the formerly slow rate of FIB-SEM imaging.

(Digital Presentation) Three-Dimensional Pore-Scale Modelling of NMC Cathodes Using Multi-Resolution FIB-SEM Images

Lithium-ion battery (LIB) cathodes are porous electrodes made of active material (AM) that stores lithium, a composite of carbon additives and polymeric binder (CBD) that facilitates electron transport and ensures the mechanical integrity of the electrode, and electrolyte-filled pore space that facilitates lithium-ion transport [1]. The volume fraction and morphology of the different constituents at the microscale necessarily determine transport properties and influence the measurable performance [2]. In this work, the impact of NMC electrode microstructure on the effective transport properties is studied using FIB-SEM-based three-dimensional (3D) particle-resolved microscale simulations. The effect of AM and CBD bulk electronic conductivity on the effective electronic conductivity is first studied and used to highlight that the impact of the AM bulk conductivity is negligible compared to that of the CBD. Next, the impact of CBD volume fraction, in isolation from its morphology, is studied using morphological operations by eroding and dilating the CBD phase in the FIB-SEM images and analyzing its impact on the effective conductivity using multiple 3D reconstructions. Increasing the CBD volume fraction results in a nonlinear increase in the effective electronic conductivity. To study the effect of CBD morphology, two stochastic CBD reconstruction techniques are proposed. The first method places new CBD voxels preferentially next to existing CBD voxels, and the second method deposits the CBD randomly in the pore space. The effective electronic conductivity for microstructures containing stochastic CBD morphologies is calculated and compared to that evaluated for microstructures with eroded and dilated CBD. The CBD generated stochastically results in a predicted higher effective electronic conductivity primarily due to a lower CBD tortuosity when compared to the CBD generated with morphological operations. Finally, the impact of CBD porosity on electrode tortuosity is studied by estimating the pore-phase tortuosity considering a solid and a porous CBD. The diffusivity of the porous CBD is estimated using multi-resolution FIB-SEM images. Results show that not accounting for the CBD porosity increases the electrode tortuosity by a factor of up to three at low electrode porosities.

(Invited) Anode-Free Sodium Metal Batteries

Sodium-ion batteries (SIBs) have been regarded as one of the most promising alternatives to lithium-ion batteries (LIBs) due to their analogous working mechanism but greater abundance. The cost-effectiveness of Na batteries is expected to overtake that of LIBs in terms of electromobile applications if their energy densities can reach 200 Wh kg-1. In an anode-free configuration, all active sodium is stored in the cathode while anode only contains current collector with zero excess sodium, therefore achieving maximized energy density, significantly reduced cost, and simplified manufacture procedures. However, the anode-free batteries often suffer rapid capacity decay due to the absence of a reservoir to replenish the Na loss during cycling. In this work, we employed repeated cold rolling and folding to fabricate a metallurgical composite of sodium-antimony-telluride Na2(Sb2/6Te3/6Vac1/6) dispersed in electrochemically active sodium metal, termed “NST-Na”. This new intermetallic has a vacancy-rich thermodynamically stable fcc structure and enables state-of-the-art electrochemical performance in widely employed carbonate and ether electrolytes. NST-Na achieves 100% depth-of-discharge (DOD) in 1 M NaPF6 in G2, with 15 mAh cm-2 at 1 mA cm-2 and CE of 99.4%, for 1000 hours of plating/stripping. Sodium metal batteries (SMB, NMB) with NST-Na and Na3V2(PO4)3 (NVP) or sulfur cathodes give significantly improved energy, cycling and CE (> 99%). Anode-Free battery with NST collector and NVP obtains 0.23% capacity decay per cycle. Imaging and tomography using (cryo-)FIB sectioning, (cryo-)SEM, and (cryo-)TEM imaging indicate that sodium metal fills the open space inside the self-supporting sodiophilic NST skeleton, resulting in dense (pore-free and SEI-free) metal deposits with flat surfaces. The baseline Na deposit consists of filament-like dendrites and Dead Metal, intermixed with pores and SEI. Density functional theory (DFT) calculations show that uniqueness of NST lies in the thermodynamic stability of Na atoms (rather than clusters) on its surface that leads to planar wetting, and in its own stability that prevents decomposition during cycling. Figure 1

Integration of multi-scale porosimetry and multi-modal imaging in the study of structure-transport relationships in porous catalyst pellets

The forming process for heterogeneous catalyst pellets impacts on reactor performance. In order to intelligently optimise the product formulation and manufacturing procedure, the impact of fabrication options on the resultant pore structure and mass transfer properties must be fully understood. In this work, the more direct information possible from multi-modal imaging methods has been combined with the more statistically-representative, multi-scale data from porosimetry, including the rarely-used gas overcondensation technique, to characterise batches of methanol synthesis catalyst tablets made using different feed types. Despite the hierarchies of complexity of the porous pellets revealed by the computerised X-ray tomography and FIB-SEM images, the impact on mass transfer of controlled modifications to the void space, achieved through mercury porosimetry, could be modelled using a relatively simple random pore-bond network. The characteristic parameters for the model were obtained from a percolation theory-based analysis of the overcondensation data. A quantitative relationship was thereby obtained between the structural information contained within the overcondensation isotherms and the rate of mass uptake of gas into the porous pellets. This revealed the differential importance to mass transfer of particular sets of pores, associated with certain pellet structural features, and the impact on tortuosity of pellet fabrication parameters such as particle feed size.

In Situ Sol-Gel Synthesis of Unique Silica Structures Using Airborne Assembly: Implications for In-Air Reactive Manufacturing.

Optical trapping enables the real-time manipulation and observation of morphological evolution of individual particles during reaction chemistry. Here, optical trapping was used in combination with Raman spectroscopy to conduct airborne assembly and kinetic experiments. Micro-droplets of alkoxysilane were levitated in air prior to undergoing either acid- or base-catalyzed sol–gel reaction chemistry to form silica particles. The evolution of the reaction was monitored in real-time; Raman and Mie spectroscopies confirmed the in situ formation of silica particles from alkoxysilane droplets as the product of successive hydrolysis and condensation reactions, with faster reaction kinetics in acid catalysis. Hydrolysis and condensation were accompanied by a reduction in droplet volume and silica formation. Two airborne particles undergoing solidification could be assembled into unique 3D structures such as dumb-bell shapes by manipulating a controlled collision. Our results provide a pipeline combining spectroscopy with optical microscopy and nanoscale FIB–SEM imaging to enable chemical and structural insights, with the opportunity to apply this methodology to probe structure formation during reactive inkjet printing.

Noise Reconstruction and Removal Network: a New Way to Denoise FIB-SEM Image

Noise Reconstruction and Removal Network: a New Way to Denoise FIB-SEM Image

Reverse osmosis membrane compaction and embossing at ultra-high pressure operation

Herein, we describe the performance (i.e., flux and rejection) of commercially-available, thin film composite brackish water RO (BWRO), seawater RO (SWRO) and high-pressure RO (HPRO) membranes operating at pressures from 14 bar (200 psi) to 207 bar (3000 psi). For each membrane material, we elucidate the impacts to performance using a porous metal frit and woven tricot mesh permeate carrier materials from commercial HPRO, SWRO, BWRO and tap water RO (TWRO) membrane modules. The water permeability of all tested membranes declines with increasing pressure, whereas rejection behaves differently for different combinations of membrane type and permeate carrier. Cross-sectional SEM and FIB-SEM images confirm permanent reduction of the polysulfone support membrane thickness (38% to 60%) as well as collapse of support membrane skin layer pores – both of which may contribute to the observed performance decline. Also, at ultra-high pressures, permeate carrier materials with higher porosity cause greater embossing and, ultimately, coating film damage (defect formation) that leads to increased salt passage (loss of salt rejection). In contrast, the permeate carriers with lower porosity still lost water permeability, but maintained higher rejection. Finally, all of the observed compaction/embossing-related performance decline occurs within about 60 min after a membrane coupon was exposed to ultra-high pressure.