3D Scanning Electron Microscopy Research Articles

Influence of sample preparation on the multi scale structure of sand-clay mixtures

This paper focuses on the influence of sample preparation on the multi scale structure of sand-clay mixtures. Three different protocols to mix silica and kaolinite were tested in the laboratory to identify the one providing the most homogeneous microstructure. From the macroscopic to the microscopic scales, optical observation, 3D X-ray tomography, 2D scanning electron microscopy (SEM) and 2D environmental scanning electron microscopy (ESEM) were carried out on wet and dry samples. This paper provides a first insight on the mechanisms of sand clay mixing from the cm to μm scale. Preliminary results demonstrate that the microstructures of the samples prepared by the three procedures have similar macroporosities based on imaging techniques. However, the preparation which consists in mixing the sand firstly, followed by water and clay provides a more homogeneous microstructure with silica grains well-surrounded by an oriented clay layering, probably due to a geometrical effect. Understanding the formation of the oriented clay layering brings microstructural features that will help to better explain the grain displacements and rotations during direct shear tests, the behaviour at the pile sand-clay soil interfaces and to formulate sand clay microstructure models.

Accuracy of three digital workflows for implant abutment and crown fabrication using a digital measuring technique

Statement of problemThe accuracy of a full digital workflow using an Atlantis abutment and a milled zirconia crown; a full digital workflow with a 3Shape split-file workflow using a zirconia abutment and crown; and an interrupted digital workflow using an Atlantis abutment and a milled zirconia crown is unclear. PurposeThe purpose of this in vitro study was to compare 2 full digital workflows relative to an interrupted workflow for restoring an implant with a custom abutment and crown. The secondary purpose of this study was to validate a digital means of measuring internal fit and marginal discrepancy using engineering software programs. Material and methodsThree workflows were evaluated. The first group, interrupted digital Atlantis (IDA) workflow, included a customized Atlantis abutment that was designed, received, and then rescanned for the definitive crown design. The second group, full digital Atlantis (FDA) workflow, included a customized Atlantis abutment and its corresponding standard tessellation language (STL) file, the Atlantis Core File, which was immediately imported into design software and used for crown design and milling. The third group, full digital split-file (FDSF) workflow, used 3Shape's full digital workflow for abutment and crown design called the split-file workflow, in which the crown and abutment were designed and milled simultaneously. All restorations were evaluated with standardized measurements using a scanning electron microscope (SEM) for 2D measurements, followed by standardized measurements using Geomagic Control, an engineering software program, which facilitated 3D evaluations of the specimens. ResultsThe 2 Atlantis workflows, IDA and FDA, had statistically smaller marginal openings (P=.002) than the FDSF when measured using 2D SEM. The FDA had a statistically smaller 2D SEM marginal gap than the other 2 groups, IDA (P=.002) and FDSF (P=.002). The FDA had a statistically smaller 3D Geomagic marginal gap than the other 2 groups, IDA (P=.004) and FDSF (P=.006). The FDSF had a statistically smaller 3D Geomagic internal fit than the other 2 groups, FDA and IDA (both P=.006). ConclusionsAll 3 workflows evaluated in this study showed clinically acceptable results in terms of mean marginal gap below 120 μm. The SEM evaluation of mean marginal opening revealed that IDA and FDA mean marginal openings were statistically smaller than the FDSF mean marginal opening. SEM and Geomagic measurements revealed that the FDA mean marginal gap was significantly smaller than IDA and FDSF mean marginal gaps. Geomagic evaluation of mean internal fit revealed that the FDSF was significantly smaller than IDA and FDA. The use of Geomagic to measure and evaluate mean marginal gap and mean internal fit as defined in this study proved to be an acceptable form of measurement with statistical validation.

Description of Ore Particles from X-Ray Microtomography (XMT) Images, Supported by Scanning Electron Microscope (SEM)-Based Image Analysis.

In this paper, three-dimensional (3D) image data of ore particle systems is investigated. By combining X-ray microtomography with scanning electron microscope (SEM)-based image analysis, additional information about the mineralogical composition from certain planar sections can be gained. For the analysis of tomographic images of particle systems the extraction of single particles is essential. This is performed with a marker-based watershed algorithm and a post-processing step utilizing a neural network to reduce oversegmentation. The results are validated by comparing the 3D particle-wise segmentation empirically with 2D SEM images, which have been obtained with a different imaging process and segmentation algorithm. Finally, a stereological application is shown, in which planar SEM images are embedded into the tomographic 3D image. This allows the estimation of local X-ray attenuation coefficients, which are material-specific quantities, in the entire tomographic image.

Abstract 3296: SMMART: Serial measurements of molecular and architectural responses to therapy

Abstract SMMART is a precision medicine research program focused on understanding the evolution of actionable biology and mechanisms of resistance in human tumors during therapy. This is accomplished through in depth functional, ‘omic and multiscale image analysis of longitudinal samples acquired during treatment. Here we present a case report detailing the insights that can be gained from the comparative analysis of pre- and post-treatment biopsy specimens in a late-stage metastatic breast cancer patient. To understand the molecular evolution of cancer, we interrogated genomics with targeted and whole exome sequencing, transcriptomics with RNA and gene-fusion sequencing, and proteomics with reverse phase protein arrays. To understand cellular organization and architectural changes, we employed multi-scale imaging tools, including scanning electron microscopy (SEM), cyclic immunofluorescence, immune cell profiling with cyclic immunohistochemistry, and traditional pathological assessment. During the course of treatment, we monitored patient response to therapy with clinical imaging, circulating tumor DNA sequencing and cancer protein assessment. Individual assays revealed key aspects of how this individual's cancer evolved under therapeutic pressure. For example, mutational profiling revealed the patterns of clonal evolution and the acquisition of new genetic driver events. 2D and 3D SEM showed changes in ECM organization, macropinocytosis, mitochondrion size, number and density and number and organization of filopodia-like protrusions. We used a 30-color cyclic immunofluorescence analysis to identify differences in cancer cell proliferation and differentiation state, as well as the composition and organization of infiltrating immune cells. In addition, integrative analyses of multiple data types provided insight into the evolution of actionable biology within this patient's disease. This included changes in the suitability of the patient for immune checkpoint inhibitors as well as specific tyrosine kinase inhibitors. The comprehensive molecular and architectural characterization of an individual patient's cancer at multiple time points provides biologically novel and clinically relevant insight into the ways in which cancers become resistant to treatment. Citation Format: Brett Johnson, Jamie Keck, Max Morris, Kiara Siex, Annette Kolodzie, Swapnil Parmar, Jessica Riesterer, Koei Chin, Summer Gibbs, Laura Heiser, Paul Spellman, Kyle Ellrott, Ozgun Babur, Emek Demir, Adam Margolin, Jeremy Goecks, Lisa Coussens, Raymond Bergan, Joe Gray. SMMART: Serial measurements of molecular and architectural responses to therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3296.

Effect of ZnDTP triboflim's morphology on friction behaviors of DLC coatings: Tribofilm characterization by 3D scanning electron microscope observation

Effect of ZnDTP triboflim's morphology on friction behaviors of DLC coatings: Tribofilm characterization by 3D scanning electron microscope observation

Preventing damage and redeposition during focused ion beam milling: The “umbrella” method

Focused ion beam (FIB) milling has enabled the development of key microstructure characterization techniques (e.g. 3D electron backscatter diffraction (EBSD), 3D scanning electron microscopy imaging, site-specific sample preparation for transmission electron microscopy, site-specific atom probe tomography), and micro-mechanical testing techniques (e.g. micro-pillar compression, micro-beam bending, in-situ TEM nanoindentation). Yet, in most milling conditions, some degree of FIB damage is introduced via material redeposition, Ga+ ion implantation or another mechanism. The level of damage and its influence vary strongly with milling conditions and materials characteristics, and cannot always be minimized. Here, a masking technique is introduced, that employs standard FIB-SEM equipment to protect specific surfaces from redeposition and ion implantation. To investigate the efficiency of this technique, high angular resolution EBSD (HR-EBSD) has been used to monitor the quality of the top surface of several micro-pillars, as they were created by milling a ringcore hole in a stress-free silicon wafer, with or without protection due to an “umbrella”. HR-EBSD provides a high-sensitivity estimation of the amount of FIB damage on the surface. Without the umbrella, EBSD patterns are severely influenced, especially within 5 µm of the milled region. With an optimized umbrella, sharp diffraction patterns are obtained near the hole, as revealed by average cross correlation factors greater than 0.9 and equivalent phantom strains of the order 2 × 10−4. Thus, the umbrella method is an efficient and versatile tool to support a variety of FIB based techniques.

Modeling, validation and verification of three-dimensional cell-scaffold contacts from terabyte-sized images

BackgroundCell-scaffold contact measurements are derived from pairs of co-registered volumetric fluorescent confocal laser scanning microscopy (CLSM) images (z-stacks) of stained cells and three types of scaffolds (i.e., spun coat, large microfiber, and medium microfiber). Our analysis of the acquired terabyte-sized collection is motivated by the need to understand the nature of the shape dimensionality (1D vs 2D vs 3D) of cell-scaffold interactions relevant to tissue engineers that grow cells on biomaterial scaffolds.ResultsWe designed five statistical and three geometrical contact models, and then down-selected them to one from each category using a validation approach based on physically orthogonal measurements to CLSM. The two selected models were applied to 414 z-stacks with three scaffold types and all contact results were visually verified. A planar geometrical model for the spun coat scaffold type was validated from atomic force microscopy images by computing surface roughness of 52.35 nm ±31.76 nm which was 2 to 8 times smaller than the CLSM resolution. A cylindrical model for fiber scaffolds was validated from multi-view 2D scanning electron microscopy (SEM) images. The fiber scaffold segmentation error was assessed by comparing fiber diameters from SEM and CLSM to be between 0.46% to 3.8% of the SEM reference values. For contact verification, we constructed a web-based visual verification system with 414 pairs of images with cells and their segmentation results, and with 4968 movies with animated cell, scaffold, and contact overlays. Based on visual verification by three experts, we report the accuracy of cell segmentation to be 96.4% with 94.3% precision, and the accuracy of cell-scaffold contact for a statistical model to be 62.6% with 76.7% precision and for a geometrical model to be 93.5% with 87.6% precision.ConclusionsThe novelty of our approach lies in (1) representing cell-scaffold contact sites with statistical intensity and geometrical shape models, (2) designing a methodology for validating 3D geometrical contact models and (3) devising a mechanism for visual verification of hundreds of 3D measurements. The raw and processed data are publicly available from https://isg.nist.gov/deepzoomweb/data/ together with the web -based verification system.

Experimental and numerical investigations of concrete behaviour at meso-level during quasi-static splitting tension

The paper describes experimental and numerical results of quasi-static splitting tensile tests on concrete specimens at meso-scale level. The experiments were carried out on cylindrical specimens with the diameter of 0.15 m. The loading strip was made of plywood or steel. Fracture in concrete was detected at the aggregate level by means of three non-destructive methods: 3D X-ray micro-computed tomography, 2D scanning electron microscope and manual 2D digital microscope. The discrete element method was used to directly simulate experiments at the meso-scale. Concrete was modelled as a random heterogeneous 4-phase material composed of aggregate particles, cement matrix, interfacial transitional zones and macro-voids based on micro-tomographic images. Two-dimensional calculations with real concrete microstructure were carried out. The effect of the different loading/supporting strip type on the stress-strain curve and fracture process was studied. This effect proved to be significant. A satisfactory agreement between numerical and experimental results was achieved. The evolution of contact normal forces, coordination number, broken contacts, grain rotations and crack displacements was also investigated. In addition, each energy component was calculated and analyzed at a different stress-displacement stage.

Study of erosive surface characterization of copper alloys under different test conditions

In this study, the erosive behavior of copper alloy has been assessed practically at different test conditions using dry compressed air jet test rig under surrounding room temperature. Asymmetrical silica sand (SiO2) is taken into account as erodent particle within the range of 300-600 µm. The impact velocities of 30–50 m/, impact angle 15–90° and stand-off distance 15–25 mm are chosen as operating parameters to investigate the variation of data of erosion rate. The highest level of erosion is obtained at impact angle 15° which ensures the ductility behavior of the tested copper alloys. Increased trends of erosion are observed at increased velocity. Mass loss of copper alloy decreases with the increase of standoff distance. The range of erosion varies from 26.82%-39.83%, 26.12%-40.63%, 36.87%-30.33% and 39.29%-27.86% for erodent size, impact velocity, impact angle and stand-off distance respectively. After erosion process, the damage propagation on surfaces is inspected utilizing Scanning Electron Microscope (SEM) for the affirmation conceivable of nature of the wear behavior. Damage surfaces of copper alloy in some particular cases indicate the detachment of large fragments and plastic deformation with pitting and ploughing action. 3D SEM was used to determine the roughnesses of damage surfaces at different processing and operating conditions. The biological composition of eroded test samples is observed by energy dispersive X-ray analysis (EDX) examination.

Microstructural Aspects of TBC`s Deposited on Internal Combustion Engine Valve Materials

The discs of the intake or exhaust valves are vital organs of internal combustion engines, being subjected to extreme operating conditions, thermal, mechanical and chemical types. One of the goals of researches in this area is related to thermal insulation of the combustion chamber of internal combustion engines, which could enhance their performance in operation. In this article we analysed the microstructural aspects of some coatings obtained from powders with thermal barrier role on specific materials for internal combustion engines valves. There were used as substrate samples of low alloy steels with Si and high alloyed steels with Cr, Ni and Mn. Using the facility SPRAYWIZARD 9MCE for atmospheric plasma spraying, two types of thermal barrier coatings were produced, from powders based on zirconia and alumina. The samples were analyzed in terms of microstructure using the QUANTA 200 3D scanning electron microscope and the X`PERT PROMD diffractometer. Observations were made both on the longitudinal surface of the coating in order to evaluate it and on the cross-section to evaluate the substrate-coating interface, the influence of deposition temperatures on the substrate and aspect/microstructure on its depth. XRD analysis revealed a cubic structure of aluminum oxide, respectively zirconium oxide. The identified morphology is a specific "splat" one for the ceramic coatings. Surface appearance shows tiny pores and cracks specific to the spraying method. The resulted coatings present a significant compactness and adherence to the substrate, which recommends them for further thermal behaviour testing.

Slanted support window-based stereo matching for surface reconstruction of microscopic samples

This work is to address the limitations of 2D Scanning Electron Microscopy (SEM) micrographs in providing 3D topographical information necessary for various types of analysis in biological and biomedical sciences as well as mechanical and material engineering by investigating modern stereo vision methodologies for 3D surface reconstruction of microscopic samples. To achieve this, micrograph pairs of the microscopic samples are acquired by utilizing an SEM equipped with motor controlled specimen stage capable of precise translational, rotational movements and tilting of the specimen stage. After pre-processing of the micrographs by SIFT feature detection/description followed by RANSAC for matching outlier removal and stereo rectification, a dense stereo matching methodology is utilized which takes advantage of slanted support window formulation for sub-pixel accuracy stereo matching of the input images. This results in a dense disparity map which is used to determine the true depth/elevation of individual surface points. This is a major improvement in comparison to previous matching methodologies which require additional post-processing refinement steps to reduce the negative effects of discrete disparity assignment or the blurring artifacts in near the edge regions. The provided results are great representatives of the superior performance of the slanted support window assumption employed here for surface reconstruction of microscopic samples.

Microstructural Characterization of Ni/YSZ Electrodes in a Solid Oxide Electrolysis Stack Tested for 9000 Hours

The performance of solid oxide electrolysis cells (SOEC) is affected by microstructural changes inside the cell. In this work detailed post-mortem characterization is conducted on an SOEC stack tested for electrolysis of steam over 9000 h [1]. The stack, produced by Topsoe Fuel Cell A/S, consists of 25 identical repeating units connected in serial. Each repeating unit includes an SOEC cell and neighboring interconnects (ICs). The SOEC cell has a Ni-YSZ support layer and fuel electrode, a YSZ electrolyte, a LSCF-CGO (LSCF: (La,Sr)(Co,Fe)O3-δ, CGO:(Ce,Gd)O2) oxygen electrode and a CGO barrier layer between the electrolyte and the oxygen electrode. The objective of the present investigation is to identify modifications in the active Ni-YSZ electrode microstructure, which are believed to strongly affect the SOEC cell and stack performance. These microstructural changes are quantified thorough 2D and 3D microstructure analyses. Based on micrographs recorded for the 9 kh tested stack and a reference cell (i.e. a cell from the same production batch as those in the stack, but not long-term tested), a relative quantification of Ni, YSZ and pore phase fractions and particle sizes has been obtained through scanning electron microscopy (SEM) imaging analysis. The mean intercept length principle has been used to investigate 2D SEM images recorded on different cell locations. The ease of this type of characterization makes it possible to investigate several locations in the long term tested stack: both fuel electrode inlet and outlet, directly under the contact point between the IC and at the point where the cell is in contact with the gas channel. By comparing results of the reference and tested cell, significant changes in Ni and pore size are observed while the YSZ backbone does not show substantial changes. The 9000 h electrolysis testing results in a decrease in the Ni phase fraction and an increase in Ni particle size. Compared to the reference cell, the biggest microstructural change is observed at the location where the cell is directly in contact with the IC, where the Ni phase fraction is decreased from 28 % (reference) to 18 % and the Ni mean intercept length is increased from ~1 μm (reference) to ~1.4 μm. Based on the 2D image analysis locations of special interest were selected for 3D reconstruction of the electrode structure by focused-ion-beam (FIB) serial sectioning. The 3D data provides information on the true particle size distribution, avoiding the assumptions that need to be made for the 2D data. Besides, the 3D analysis allows the transport pathways to be characterized through each of the phase networks [2]. A comparison between 2D and 3D data is carried out to concisely investigated microstructural changes and relate them with the cell performance during long-term operation. [1] A. Brisse, J. Schefold, G. Corre, Q. Fu. Performance and Lifetime of Solid Oxide Electrolyzer Cells and Stacks. 11thEuropean SOFC & SOEC Forum, July 2014 [2] Peter Stanley Jørgensen, Søren Lyng Ebbehøj, and Anne Hauch. "Triple phase boundary specific pathway analysis for quantitative characterization of solid oxide cell electrode microstructure." Journal of Power Sources 279 (2015): 686-693. Figure 1

Multi-scale 3D investigations of a commercial 18650 Li-ion battery with correlative electron- and X-ray microscopy

In the present study, a commercial 18650 Li-ion cylindrical cell is investigated with non-destructive 3D X-ray microscopy across a range of length scales, beginning with a survey of the entire cell and non-destructively enlarging a smaller section. Active materials are extracted from a disassembled cell and imaging performed using a combination of sub-micron X-ray microscopy and 2D scanning-electron microscopy, which point toward the need for multi-scale analysis in order to accurately characterize the cell. Furthermore, a small section is physically isolated for 3D nano-scale X-ray microscopy, which provides a measurement of porosity and enables the effective diffusivity and 3-dimensional tortuosities to be calculated via computer simulation. Finally, the 3D X-ray microscopy data is loaded into a correlative microscopy environment, where a representative sub-surface region is identified and, subsequently, analyzed using electron microscopy and energy-dispersive X-ray spectroscopy. The results of this study elucidate the microstructural characteristics and potential degradation mechanisms of a commercial NCA battery and, further, establish a technique for extracting the Bruggeman exponent for a real-world microstructure using correlative microscopy.

ELEMENT COMPOSITION COMPARISON OF ELECTRIC-SPARK COATINGS AND ELECTROSPARKSINTERED MATERIAL

One of the promising methods of powder obtaining practically from any conductive material, including hard alloy, characterized by relatively low energy costs and cleanliness of the process, is method electroerosion dispersion (EED). Currently there is no full information on initial composition, regimes and environment impact on the properties of disperse systems and recommendations on the effective technologies providing their sintering and hardening in the scientific and technical literature. Thus this prevents from the use of this method. For sintered parts hardening, it is helpful to use electric spark machining (ESM). ESM is technologically flexibilite, cheap and it helps to obtain coverings with a wide range of properties. However, in many cases the properties of electrospark coatings depend both on the composition, structure and properties of the electrode material, and on the properties of the substrate material. Complex theoretical and experimental studies are required to develop a complex technology for the production of disperse systems using electroerosion dispersion method and their hardening by electric spark machining, charecterised by good stress-related properties and performance. The purpose of this work is to research the elemental composition of electrospark coatings and electroerosion sintered substrates made of high-speed steel. When the experiments were set up, a metal powder was obtained from the waste of high-speed steel grade P6M5 when using a device for electroerosion dispersion of conductive materials. The resulting electroerosion powder consisted of particles of a spherical and elliptical shape measuring from 25 nm to 50 μm. The average particle size of the powder was 19.72 μm, and the specific surface area was 16725.95 cm2 / cm3. The electro-erosion powder was pressed by a hydrostatic method using an EPSI press. The powder was poured into a rubber hermetical mold then it was placed in a hydrostat working chamber where there was a liquid pressure of 300 MPa created by means of a high-lift pump. Nabertherm VHT 8/22 GR. Sintering was held in a vacuum at a temperature of 1050 ° C for 2 hours . Electrospark coatings on sintered sample material made from electroerrosion high-speed steel were produced using VK8 electrodes and UR-121 machine. Using EDAX energy-dispersive X-ray analyzer, built into QUANTA 200 3D scanning electron microscope, spectra of characteristic X-ray radiation were obtained at various points on the surface of the sample and along the cross-section. Based on the conducted studies it was established that the main elements in the electrospark coating are iron, molybdenum and tungsten, and sintering was held in a vacuum at a temperature of 1050 ° C for 2 hours . Electrospark coatings on sintered sample material made from electroerrosion high-speed steel were produced using VK8 electrodes and UR-121 machine. Using EDAX energy-dispersive X-ray analyzer, built into QUANTA 200 3D scanning electron microscope, spectra of characteristic X-ray radiation were obtained at various points on the surface of the sample and along the cross-section. Based on the conducted studies it was established that the main elements in the electrospark coating are iron, molybdenum and tungsten, and in the substrate only iron and molybdenum. the substrate only iron and molybdenum. Based on the conducted studies it was established that the main elements in the electrospark coating are iron, molybdenum and tungsten, and the main elements in the substrate are only iron and molybdenum.

A hybrid 3D SEM reconstruction method optimized for complex geologic material surfaces

Reconstruction methods are widely used to extract three-dimensional information from scanning electron microscope (SEM) images. This paper presents a new hybrid reconstruction method that combines stereoscopic reconstruction with shape-from-shading calculations to generate highly-detailed elevation maps from SEM image pairs. The method makes use of an imaged glass sphere to determine the quantitative relationship between observed intensity and angles between the beam and surface normal, and the detector and surface normal. Two specific equations are derived to make use of image intensity information in creating the final elevation map. The equations are used together, one making use of intensities in the two images, the other making use of intensities within a single image. The method is specifically designed for SEM images captured with a single secondary electron detector, and is optimized to capture maximum detail from complex natural surfaces. The method is illustrated with a complex structured abrasive material, and a rough natural sand grain. Results show that the method is capable of capturing details such as angular surface features, varying surface roughness, and surface striations.

Correlative Fluorescence and Electron Microscopy in 3D-Scanning Electron Microscope Perspective.

The ability to correlate fluorescence microscopy (FM) and electron microscopy (EM) data obtained on biological (cell and tissue) specimens is essential to bridge the resolution gap between the data obtained by these different imaging techniques. In the past such correlations were limited to either EM navigation in two dimensions to the locations previously highlighted by fluorescence markers, or subsequent high-resolution acquisition of tomographic information using a TEM. We present a novel approach whereby a sample previously investigated by FM is embedded and subjected to sequential mechanical polishing and backscatter imaging by scanning electron microscope. The resulting three dimensional EM tomogram of the sample can be directly correlated to the FM data. © 2017 by John Wiley & Sons, Inc.

How to fragment peralkaline rhyolites: Observations on pumice using combined multi-scale 2D and 3D imaging

Peralkaline rhyolites are volatile-rich magmas that typically erupt in continental rift settings. The high alkali and halogen content of these magmas results in viscosities two to three orders of magnitude lower than in calc-alkaline rhyolites. Unless extensive microlite crystallisation occurs, the calculated strain rates required for fragmentation are unrealistically high, yet peralkaline pumices from explosive eruptions of varying scales are commonly microlite-free. Here we present a combined 2D scanning electron microscopy and 3D X-ray microtomography study of peralkaline rhyolite vesicle textures designed to investigate fragmentation processes. Microlite-free peralkaline pumice textures from Pantelleria, Italy, strongly resemble those from calc-alkaline rhyolites on both macro and micro scales. These textures imply that the pumices fragmented in a brittle fashion and that their peralkaline chemistry had little direct effect on textural evolution during bubble nucleation and growth. We suggest that the observed pumice textures evolved in response to high decompression rates and that peralkaline rhyolite magmas can fragment when strain localisation and high bubble overpressures develop during rapid ascent.

How long does the volumizing effect of a Zingiber officinale-based lip plumper last?

Lip plumpers should enhance lip volume. It has been shown that no noticeable result was obtained after long term use of these products. The present study has been carried out to assess lip plumpers' short term effectiveness within 2 h from application. Effectiveness was assessed using non-invasive techniques. The effect on vascularisation was analyzed with the Mexameter MX 16® , and the volume enhancing effect was assessed by anthropometric measures and profilometry analysis from 3D scanning electron microscope (SEM) images using Alicona's MEX software. Sixty female volunteers were recruited for the study and the measurements were taken 15, 30, 60, 90 and 120 min after product application. Product application produced a statistically significant increase of lip vascularisation during the first 15 min, which stayed unchanged until the 30th min, then decreased in intensity. The volumizing effect was revealed by 3D profilometry analysis only, not by anthropological measurements. The use of 3D SEM images showed an increase of 0.50 mm in the protrusion of the lip vermilion (MHP parameter) during the first 15 min from product application. Results suggest that the lip plumper temporarily enhances vasodilation and increases lip volume.

Stochastic shale permeability matching: Three-dimensional characterization and modeling

The recently-discovered promise of shale-gas reservoirs necessitates their characterization. As a first step, two-dimensional (2D) scanning electron microscope (SEM) imaging can provide excellent view of the complexity associated with such reservoirs, and has been used in recent years to study organic materials, clays, minerals, and the pores in shales. Other important information, such as the connectivity of the pores in 3D and such macroscopic properties as the permeability are difficult to infer from 2D SEM images. Newer techniques, such as focused ion-beam SEM (FIB-SEM) have been utilized to overcome the shortcomings. The extremely small sample size and the costs associated with the FIB-SEM technique limit, however, wide use of the FIB-SEM in characterization of shale samples. An alternative approach is to use the recently developed advanced algorithms for 3D reconstruction that use one or a few 2D samples. Such methods may not, however, be able to fully reproduce the shale permeability. To accurately reproduce the permeability, we propose a new method based on a combination of the Metropolis-Hastings and the genetic algorithms. The new method learns from its own previously generated realizations of the shale and produces models that match the existing permeability data. The method is validated with the measured permeability for an actual 3D shale sample. It generates an ensemble of stochastic realizations that honor the permeability data, which may then be used for more accurate characterization of shale gas reservoir and analysis of their pore network.

Bayesian deconvolution of scanning electron microscopy images using point-spread function estimation and non-local regularization.

Microscopy is one of the most essential imaging techniques in life sciences. High-quality images are required in order to solve (potentially life-saving) biomedical research problems. Many microscopy techniques do not achieve sufficient resolution for these purposes, being limited by physical diffraction and hardware deficiencies. Electron microscopy addresses optical diffraction by measuring emitted or transmitted electrons instead of photons, yielding nanometer resolution. Despite pushing back the diffraction limit, blur should still be taken into account because of practical hardware imperfections and remaining electron diffraction. Deconvolution algorithms can remove some of the blur in post-processing but they depend on knowledge of the point-spread function (PSF) and should accurately regularize noise. Any errors in the estimated PSF or noise model will reduce their effectiveness. This paper proposes a new procedure to estimate the lateral component of the point spread function of a 3D scanning electron microscope more accurately. We also propose a Bayesian maximum a posteriori deconvolution algorithm with a non-local image prior which employs this PSF estimate and previously developed noise statistics. We demonstrate visual quality improvements and show that applying our method improves the quality of subsequent segmentation steps.