Bulk Techniques Research Articles

Recent developments in microfluidic technology for synthesis and toxicity-efficiency studies of biomedical nanomaterials

Microfluidic technology is a relatively new field among the various conventional bulk techniques employed for nanomaterial synthesis. Nanoparticles (NPs) produced using such methods generally have poor surface features, morphology, uncontrolled size and broad size distributions. NPs especially used in the biomedical sector require a degree of control over their size, morphology, and polydispersity to improve their functionality. To synthesize such NPs, microfluidic devices are ideal as parameters such as mixing rates, flow rates, mixing volumes, multiphase reactions can be controlled on the micro/nanoscale. There are several strategies and challenges in the synthesis of nanoparticles from organic and inorganic materials in a microfluidic platform. The challenges faced during the design and implementation of these devices, such as the large scale production and interaction with soft lithography materials, which are overcome by the use of the bulk technique in conjugation with microfluidics, use of parallelisation of the processes with the search for new fabrication materials. On the other hand, organ-on-chip (OOC) are analytical microfluidic devices in which cell cutures are present and can mimic an organ along with its physio-chemical properties to study cell-nanoparticle interaction. There are several issues with the construction of such devices as cell cultures within the device can be affected by the fabrication materials. As such new biocompatible materials are being printed into more appropriate designs, utilized to contain said cultures and reduce the risk of error in the analysis of NP properties, such as efficiency and toxicity. This review aims to discuss the recent developments in the field of synthesis as well as toxicity and efficacy evaluations of biomedical nanoparticles using microfluidic technology.

Comparing occlusal and cervical microleakage in class V restorations using two different nanohybrid resin composite with different insertion techniques

The study evaluates and compares occlusal and cervical microleakage in class V cavities restored with various techniques using two different nanohybrid composites. Sixty standardized box-shaped class V cavities preparations of 2 × 2 × 3 mm (depth, length, width) were performed on 30 teeth; each cavity has occlusal and cervical margin to be evaluated. Twelve groups were designed to be filled with a specific material (nanohybrid Filtek™ Z250 XT composite or Beautifil™ II LS Giomer) and technique (Bulk, Vertical, or Split horizontal layering technique SHLT) to compare the occlusal versus cervical microleakage. The samples were thermocycled 500 times (5 °C ± 2 °C & 55 °C ± 2 °C with 30 s dwell time) before being submerged in a 2 % buffered methylene blue solution for 24 h at 37 °C. The restorations were sectioned longitudinally in a buccolingual direction through the centers of the restoration. Then evaluated for microleakage on both occlusal and cervical margin using a stereomicroscope at x10 magnification and scored as 0, 1, 2, and 3. Resultant cervical and occlusal microleakage scores were statistically analyzed using one-way ANOVA followed by Tukey post hoc considering (p < 0.05). SHLT reveals a reduction in microleakage on both occlusal and cervical margins, and the Giomer material showed less microleakage on both margins SHLT and Bulk technique. The split horizontal layering technique showed less marginal microleakage on occlusal and cervical margins despite the material used.

Fe3+/FeT ratios of amphiboles determined by high spatial resolution single-crystal synchrotron Mössbauer spectroscopy

Abstract The Fe3+/FeT ratios (Fe3+/[Fe2++Fe3+]) in minerals can be used to understand their crystallization and post-crystallization conditions. However, as natural minerals are often zoned and contain inclusions, bulk techniques, e.g., wet chemistry, may not provide accurate Fe3+/FeT values for a single phase of interest. We determined Fe3+/FeT ratios of amphiboles in different crystallographic orientations by single-crystal synchrotron Mössbauer spectroscopy (SMS) in energy and time domain modes from four volcanic localities (Long Valley Caldera, Mount St. Helens, Lassen Volcanic Center, U.S.A., and Mt. Pinatubo, Philippines). The high spatial resolution (as low as 12 × 12 μm spot size) and standard-free nature of SMS allow the detection of intra-grain compositional heterogeneities in Fe3+/FeT with relatively low uncertainties. We combine SMS with major element compositions, water contents, and hydrogen isotope compositions to document the Fe3+/FeT ratios as a function of mineral composition and post-crystallization dehydrogenation. Spectra were fitted with up to five distinct sites: ferrous iron on M(1), M(2), M(3), and ferric iron on M(2) and M(3), consistent with X-ray diffraction studies on single crystals of amphibole. The Fe3+/FeT ratios range from 0.14 ± 0.03 (Long Valley Caldera), 0.51 to 0.63 ± 0.02 (representing intra-grain heterogeneities, Mount St. Helens) to 0.86 ± 0.03 (Lassen Volcanic Center). The latter grain experienced post-crystallization dehydrogenation, shown by its low water content (0.6 ± 0.05 wt%) and its elevated hydrogen isotope composition (δD = +25 ± 3‰ relative to SMOW). The Fe3+/FeT ratios of 0.62 ± 0.01 and 0.20 ± 0.01 of two Mt. Pinatubo grains correlate with high-Al2O3 cores and low-Al2O3 rims and smaller phenocrysts in the sample, respectively. This study shows that SMS is capable of distinguishing two different domains with dissimilar Fe3+/FeT values formed under different crystallization conditions, demonstrating that SMS in combination with major element, water, and hydrogen isotope compositions allows the interpretation of amphibole Fe3+/FeT ratios in the context of crystallization and post-crystallization processes.

Current and future perspectives of atomic force microscopy to elicit the intrinsic properties of soft matter at the single molecule level

&lt;abstract&gt; &lt;p&gt;Soft matter encompasses multitude of systems like biomolecules, living cells, polymers, composites or blends. The increasing interest to better understand their physico-chemical properties has significantly favored the development of new techniques with unprecedented resolution. In this framework, atomic force microscopy (AFM) can act as one main actor to address multitude of intrinsic sample characteristics at the nanoscale level. AFM presents many advantages in comparison to other bulk techniques as the assessment of individual entities discharging thus, ensemble averaging phenomena. Moreover, AFM enables the visualization of singular events that eventually can provide response of some open questions that still remain unclear. The present manuscript aims to make the reader aware of the potential applications in the employment of this tool by providing recent examples of scientific studies where AFM has been employed with success. Several operational modes like AFM imaging, AFM based force spectroscopy (AFM-FS), nanoindentation, AFM-nanoscale infrared spectroscopy (AFM-nanoIR) or magnetic force microscopy (MFM) will be fully explained to detail the type of information that AFM is capable to gather. Finally, future prospects will be delivered to discern the following steps to be conducted in this field.&lt;/p&gt; &lt;/abstract&gt;

Bulk and surface characterisation techniques of solar absorbers: general discussion.

Bulk and surface characterisation techniques of solar absorbers: general discussion.

Single and selective transport of Zr(IV) ions with trioctyl amine dissolved in kerosene using a multidropped liquid membrane technique.

It is very important to develop a process for selectively extracting Zr(IV) ions from the solution medium to produce zirconium metal used in industry and nuclear reactors. In this study, the parameters affecting the extraction of Zr(IV) ions were investigated using a multidropped liquid membrane (MDLM) system. Trioctyl amine (TOA) dissolved in kerosene was used as a carrier ligand in the extraction of Zr(IV) ions by the MDLM technique. The effect of carrier concentration and stripping solution concentration, pH, and the temperature in the donor phase on the transport of Zr(IV) were investigated. The optimum condition for the transportation of Zr(IV) was a 0.50 M H2SO4 solution as donor phase, 0.10 molL-1 TOA as a carrier, and 0.10 M Na2CO3 as acceptor phase. The transport percentage of Zr(IV) was increased up to >99% and the calculated activation energy which is 6.36 kcal mol-1 indicated that the process was diffusion controlled by Zr(IV) ions. The results showed that the MDLM system, which resembles a bulky membrane system in shape, is a promising technique for the extraction of Zr(IV) ions from an acidic solution. It is more practical and effective than bulk, supported, or inclusion, and emulsion liquid membrane techniques.

Low voltage quasi floating gate current mirror with improved output impedance

Current mirror with a wide variety of application has become a basic block of analogue circuits. The main parameters affecting its performances are linearity range, input compliance voltage, input and output impedance and bandwidth. In this paper, a quasi floating gate-based current mirror design is modified in terms of increasing the output impedance. An improvement was achieved without affecting the other performance parameters of current mirror. The proposed current mirror uses the gate driven quasi floating bulk technique which results in effective transconductance as the sum of gate and scaled body transconductance. This increased transconductance boosts the output impedance from 800 kilo ohms to 3 mega ohms without degrading any of the other current mirror performance parameters. The complete analysis of the proposed current mirror is done using HSpice simulator on 0.18 um twin-well CMOS technology at a supply voltage of ±0.5 V.

Micro-structural and micro-chemical investigation of Samnite high-tin bronze cuirass discs: ancient metallurgy in central Italy

In the present study, micro-structural and micro-chemical investigation of archaeological bronze artefacts provided new insight about the metallurgical manufacture of defensive weapons by the Samnite’s metalsmiths in central Italy from the archaic necropolis of Barrea (AQ) and Torrebruna (CH). In particular, the metallurgical features, the chemical composition and the manufacturing process of Cu-based high-tin alloys used to produce cuirass discs were investigated. These artifacts were used to protect the warrior’s heart (i.e. the kardiophylaches) but were also and more importantly a distinctive sign of rank and role of warriors of the archaic age (VI BC). The Samnite cuirass discs are multi-material artifacts made of a decorated bronze central part with a complex metallurgical structure, due to the presence of different Cu-Sn phases, and a surrounding iron cladding to support the disk. These discs were studied by different surface and bulk techniques, namely Optical Microscopy (OM), Field Emission Scanning Electron Microscopy coupled with energy dispersive X-ray microanalysis (FE-SEM-EDS), X-ray Diffraction (XRD) and Infrared Spectroscopy (FTIR). The combined use of these techniques proved the high technological level of the Samnite metallurgists. In fact, their particular composition, having an uncommon high content of tin, made their manufacturing process difficult because of the intrinsic brittleness of the alloy. This work disclose the ability of Samnites people to successfully manipulate fragile high tin bronze alloys by inducing temporary phase changes and, thus, facilitating the mechanical shaping of the artifact.

Atomic-Scale Insights into Nickel Exsolution on LaNiO3 Catalysts via In Situ Electron Microscopy.

Using a combination of insitu bulk and surface characterization techniques, we provide atomic-scale insight into the complex surface and bulk dynamics of a LaNiO3 perovskite material during heating in vacuo. Driven by the outstanding activity LaNiO3 in the methane dry reforming reaction (DRM), attributable to the decomposition of LaNiO3 during DRM operation into a Ni//La2O3 composite, we reveal the Ni exsolution dynamics both on a local and global scale by insitu electron microscopy, insitu X-ray diffraction and insitu X-ray photoelectron spectroscopy. To reduce the complexity and disentangle thermal from self-activation and reaction-induced effects, we embarked on a heating experiment in vacuo under comparable experimental conditions in all methods. Associated with the Ni exsolution, the remaining perovskite grains suffer a drastic shrinkage of the grain volume and compression of the structure. Ni particles mainly evolve at grain boundaries and stacking faults. Sophisticated structure analysis of the elemental composition by electron-energy loss mapping allows us to disentangle the distribution of the different structures resulting from LaNiO3 decomposition on a local scale. Important for explaining the DRM activity, our results indicate that most of the Ni moieties are oxidized and that the formation of NiO occurs preferentially at grain edges, resulting from the reaction of the exsolved Ni particles with oxygen released from the perovskite lattice during decomposition via a spillover process from the perovskite to the Ni particles. Correlating electron microscopy and X-ray diffraction data allows us to establish a sequential two-step process in the decomposition of LaNiO3 via a Ruddlesden–Popper La2NiO4 intermediate structure. Exemplified for the archetypical LaNiO3 perovskite material, our results underscore the importance of focusing on both surface and bulk characterization for a thorough understanding of the catalyst dynamics and set the stage for a generalized concept in the understanding of state-of-the art catalyst materials on an atomic level.

Disposition of Fluorine on New Firefighter Turnout Gear.

Firefighter turnout gear is essential for reducing occupational exposure to hazardous chemicals during training and fire events. Per-and polyfluoroalkyl substances (PFASs) are observed in firefighter serum, and possible occupational sources include the air and dust of fires, aqueous film-forming foam, and turnout gear. Limited data exist for nonvolatile and volatile PFASs on firefighter turnout gear and the disposition of fluorine on the individual layers of turnout gear. Further implications for exposure to fluorine on turnout gear are not well understood. Three unused turnout garments purchased in 2019 and one purchased in 2008, were analyzed for 50 nonvolatile and 15 volatile PFASs by liquid chromatography quadrupole time-of-flight mass spectrometry (LC-qTOF-MS) and gas chromatography-mass spectrometry (GC-MS), respectively. Particle-induced gamma ray emission (PIGE), a surface technique, and instrumental neutron activation analysis (INAA), a bulk technique, were used to measure total fluorine. Bulk characterization of the layers by pyrolysis-GC/MS (py-GC/MS) was used to differentiate fluoropolymer (e.g., PTFE) films from textile layers finished with side-chain polymers. The outer layer, moisture barrier, and thermal layers of the turnout gear all yielded measured concentrations of volatile PFASs that exceeded nonvolatile PFAS concentrations, but the summed molar concentrations made up only a small fraction of total fluorine (0.0016-6.7%). Moisture barrier layers comprised a PTFE film, as determined by py-GC-MS, and gave the highest individual nonvolatile (0.159 mg F/kg) and volatile PFAS (20.7 mg F/kg) as well as total fluorine (122,000 mg F/kg) concentrations. Outer and thermal layers comprised aromatic polyamide-based fibers (aramid) treated with side-chain fluoropolymers and had lower levels of individual nonvolatile and volatile PFASs. Equal concentrations of total fluorine by both PIGE and INAA on the outer and thermal layers is consistent with treatment with a side-chain fluoropolymer coating. New turnout gear should be examined as a potential source of firefighter occupational exposure to nonvolatile and volatile PFASs in future assessments.

Accelerating Battery Characterization Using Neutron and Synchrotron Techniques: Toward a Multi‐Modal and Multi‐Scale Standardized Experimental Workflow

AbstractLi‐ion batteries are the essential energy‐storage building blocks of modern society. However, producing ultra‐high electrochemical performance in safe and sustainable batteries for example, e‐mobility, and portable and stationary applications, demands overcoming major technological challenges. Materials engineering and new chemistries are key aspects to achieving this objective, intimately linked to the use of advanced characterization techniques. In particular, operando investigations are currently attracting enormous interest. Synchrotron‐ and neutron‐based bulk techniques are increasingly employed as they provide unique insights into the chemical, morphological, and structural changes inside electrodes and electrolytes across multiple length scales with high time/spatial resolutions. However, data acquisition, data analysis, and scientific outcomes must be accelerated to increase the overall benefits to the academic and industrial communities, requiring a paradigm shift beyond traditional single‐shot, sophisticated experiments. Here a multi‐scale and multi‐technique integrated workflow is presented to enhance bulk characterization, based on standardized and automated data acquisition and analysis for high‐throughput and high‐fidelity experiments, the optimization of versatile and tunable cells, as well as multi‐modal correlative characterization. Furthermore, new mechanisms, methods and organizations such as artificial intelligence‐aided modeling‐driven strategies, coordinated beamtime allocations, and community‐unified infrastructures are discussed in order to highlight perspectives in battery research at large scale facilities.

A Low-Noise High-Gain Recycling Folded Cascode Operational Transconductance Amplifier Based on Gate Driven and Quasi-Floating Bulk Technique

Operational Transconductance Amplifier (OTA) is an important circuit block used in the design of filter, amplifiers and oscillators for various analog-mixed circuit systems. However, design of a low-noise, high-gain OTA with low-power consumption is a challenging task in CMOS technology owing to high-power requirements of OTA for emulating high gain. This paper represents the design of gate-driven quasi-floating bulk recycling folded cascode (GDQFB RFC) OTA which has been shown to provide low-noise operation, emulates high gain and draws very less power. The design utilizes the gate-driven quasi-floating bulk (GDQFB) technique on a recycling folded cascode structure, which enhances the transconductance of OTA and improves its performance. All the post-layout simulation results have been obtained in 0.18-μm CMOS N-well technology using BSIM3V3 device models. The obtained results indicate very high gain of 100.4 dB, gain-bandwidth of 69 kHz, phase margin of 51.9∘ with power consumption of 2.31μW from ±0.9V supply voltage. The input referred noise emulated by proposed OTA is 0.684, 0.21 and 0.0592μV/√Hz @ 1 Hz, 10 Hz and 1 kHz, respectively. The input common mode range and output voltage swing are found to be −0.402 to 0.669 V and −0.493 to 0.610 V, respectively. Corner simulations and Monte Carlo analysis have been performed to verify the robustness of the proposed OTA. The proposed OTA can be used in design of filters and amplifiers for bio-instruments, sensor applications, neural recording applications and human implants etc.

Assessing the Physiologic Relevance of Red Blood Cell Deformability in Iron Deficiency Anemia

Background: Iron deficiency anemia (IDA), which affects individuals of all ages worldwide, is an often overlooked and undertreated component of chronic disease, despite data correlating its association with adverse outcomes in patients with cardiovascular disease (von Haehling, Nat Rev Cardiol, 2015). While red blood cells (RBCs) in IDA are known to be smaller and contain less hemoglobin than healthy RBCs, how RBC deformability is altered in IDA remains poorly understood; some ektacytometry studies have observed impaired deformability in iron deficient RBCs (idRBCs), while others described either unchanged or increased deformability (Brandão, Clin Hemorheol Microcirc, 2009). Here we ask: can single cell biophysical techniques definitively determine whether idRBCs are less deformable than healthy RBCs and how heterogenous that phenomena may be? Recent investigations into IDA's role in cardiovascular disease have generally focused on the myocardium and coronary vasculature, yet much regarding other physiologic implications remains unknown, including whether idRBCs cause microvascular obstruction or vasculopathy. To address such questions, we leveraged a suite of microvascular models we developed.Methods: We first coupled our microfluidic capillary model with μEXACT, our customized automated particle tracking program for hematologic cell-based assays, to collect high-throughput velocity tracking of single RBCs from a healthy control and 2 IDA patients (anemic for age, ferritin <10 ng/mL) to create a single cell deformability index (sDI) for each RBC (Fig 1). Next, whole blood samples collected in EDTA tubes from the control and IDA patients were perfused into both straight 100μm wide channels (mimicking large venules) and branching 30μm wide microfluidic devices (mimicking smaller venules) at a constant shear rate for 30 minutes to observe if any occlusions or obvious alterations in flow were observed (Fig 2). Finally, using the straight 100μm channel microfluidic devices, human umbilical vein endothelial cells (HUVECs) were cultured throughout each microchannel and RBCs from a healthy control and 3 IDA patients were perfused in parallel microchannels for 4 hours. The endothelialized models were then fixed, permeabilized, and immunostained with antibodies against VCAM-1 and E-selectin, known markers of endothelial inflammation. Mean fluorescence intensity was measured to quantify endothelial inflammation (Fig 3).Results: sDI distribution histograms were obtained for healthy and IDA patient RBCs. The mean sDIs for IDA patient RBCs were decreased in comparison to the healthy RBCs. Additionally, both IDA patient's RBCs lacked a subpopulation of highly deformable RBCs, likely reticulocytes, seen in the healthy RBCs (Fig 1C). There was no evidence of microchannel occlusion for the healthy control or IDA patient whole blood samples in either the straight 100μm microchannels or branching 30μm microfluidic devices (Fig 2D). Finally, in our endothelialized microfluidic model, endothelium exposed to IDA patient RBCs exhibited increased VCAM-1 and E-selectin expression over endothelium exposed to healthy RBCs (Fig 3B).Conclusions: By utilizing an array of microfluidic models we can develop a more comprehensive understanding of the role idRBCs play systemically on microvasculature. Our combined microfluidic and image analysis system demonstrated decreased deformability in idRBCs and can offer detection of subpopulation differences that cannot be fully characterized with bulk techniques such as ektacytometry. So far, our data demonstrates that while no microvascular occlusion occurs, idRBCs contribute to endothelial inflammation. Additionally, the observation that physical interactions between endothelial cells and idRBCs are sufficient to cause endothelial inflammation warrants further investigation, as generally idRBCs had not been viewed as pro-inflammatory. Ongoing studies will couple unique sDI distribution curves with the degree of endothelial inflammation, as well as elucidate how these changes are associated with the degree of IDA or clinical events such as the initiation of iron supplementation. Utilizing atomic force microscopy to better understand how the idRBC membrane impacts deformability and developing biophysical computer simulations to determine if increased idRBC-endothelium interactions are observed in silico are also planned. [Display omitted] DisclosuresLam: Sanguina, Inc.: Current holder of individual stocks in a privately-held company.

Recent progress in cytometric technologies and their applications in ecotoxicology and environmental risk assessment.

Environmental toxicology focuses on identifying and predicting impact of potentially toxic anthropogenic chemicals on biosphere at various levels of biological organization. Presently there is a significant drive to gain deeper understanding of cellular and sub-cellular mechanisms of ecotoxicity. Most notable is increased focus on elucidation of cellular-response networks, interactomes, and greater implementation of cell-based biotests using high-throughput procedures, while at the same time decreasing the reliance on standard animal models used in ecotoxicity testing. This is aimed at discovery and interpretation of molecular pathways of ecotoxicity at large scale. In this regard, the applications of cytometry are perhaps one of the most fundamental prospective analytical tools for the next generation and high-throughput ecotoxicology research. The diversity of this modern technology spans flow, laser-scanning, imaging, and more recently, Raman as well as mass cytometry. The cornerstone advantages of cytometry include the possibility of multi-parameter measurements, gating and rapid analysis. Cytometry overcomes, thus, limitations of traditional bulk techniques such as spectrophotometry or gel-based techniques that average the results from pooled cell populations or small model organisms. Novel technologies such as cell imaging in flow, laser scanning cytometry, as well as mass cytometry provide innovative and tremendously powerful capabilities to analyze cells, tissues as well as to perform in situ analysis of small model organisms. In this review, we outline cytometry as a tremendously diverse field that is still vastly underutilized and often largely unknown in environmental sciences. The main motivation of this work is to highlight the potential and wide-reaching applications of cytometry in ecotoxicology, guide environmental scientists in the technological aspects as well as popularize its broader adoption in environmental risk assessment.

Investigation of the effect of different application techniques on microhardness in bulk-fill composite resins

Aim: The aim of this study was to investigate the effect of different application techniques on microhardness in one universal resin material and three different bulk-fill composite resin materials.&#x0D; Materials and Methods: In this study, one universal composite resin (Universal Restorative 200 [U], 3M-ESPE, USA) and three different bulk-fill composite resins (Filtek-One Bulk-Fill Restorative [F]; 3M-ESPE, USA: Tetric Evo-Ceram Bulk-Fill [E]; and Ivoclar-Vivadent, Liechtenstein; Tetric N-Ceram Bulk-Fill [N], Ivoclar-Vivadent, Liechtenstein) materials were used. A total of 60 disk-shaped samples, including 20 samples from each bulk-fill composite resin group, were prepared. The polymerization of the bulk-fill composite resins in one group was completed using a 2 mm (40 sec) + 2 mm (40 sec) incremental technique, and in the other group, it was completed using a 4 mm bulk technique (40 sec). The U composite resin (control group) polymerization was completed using a 2 mm + 2 mm (40 sec) incremental technique (n = 10). The Vickers microhardness (VHN) values ​​of the samples were calculated. The data were analyzed with Kruskal–Wallis and Mann–Whitney U tests (p &lt; 0.05).&#x0D; Results: Higher VHN values ​​were found in the U composite resin compared to those in the bulk-fill composite resins (p &lt; 0.05). In the bulk technique, a lower VHN value ​​was observed in the N bulk-fill composite resin than in the control group (p &lt; 0.05), while there was no difference between the N and E composite resin groups (p &gt; 0.05). A lower N bulk-fill composite resin was observed in the groups in which the incremental technique was applied than in the control group (p &lt; 0.05). When the techniques applied to the bulk-fill composite resins were evaluated within themselves, higher VHN values ​​were observed in the E composite resin in the group in which the incremental technique was applied but not in the group in which the bulk was applied.&#x0D; Conclusion: It was observed that the content differences of composite resins were effective at different VHN values. The U composite resin (control) group showed higher VHN values than all the bulk-fill composite groups.&#x0D; &#x0D; How to cite this article: Fidan M, Gönder HY. Investigation of the effect of different application techniques on microhardness in bulk-fill composite resins. Int Dent Res 2021;11(Suppl.1):32-7. https://doi.org/10.5577/intdentres.2021.vol11.suppl1.6&#x0D; &#x0D; Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

Factors controlling pore network development of thermally mature Early Palaeozoic mudstones from the Baltic Basin (N Poland)

Understanding the formation of pore space, especially in low porosity shales (as source rocks and as unconventional resources), is critical to the oil and gas industry, since pores control the space available for hydrocarbon and participate in hydrocarbon transport. We examined 87 Ordovician and Silurian mudstone samples collected from four wells located in the Pomeranian part of the Baltic Basin (northern Poland), one of the primary Polish targets for hydrocarbon exploration. These samples represent the Pelplin, the Pasłęk, the Jantar, the Prabuty, and the Sasino Formations, which still requires more detailed porosity studies. Our study aimed to identify factors controlling porosity development, by applying bulk techniques (organic petrology and TOC analyses, quantitative mineralogy, and porosimetry) as well as nano-to microscale techniques (thin section petrography, electron microscopy). The studied samples are mainly argillaceous mudstones. The results of porosimetry measurements, combined with image analysis, indicate that the pores of all studied rocks are dominated by micropores (pores <2 nm in diameter), mesopores (2–50 nm in diameter) and small macropores. The SEM images showed three main pore types: a) voids related to clay mineral aggregates, b) pores inside organic matter particles, and c) pores between other mineral grains. In the Jantar and Sasino mudstones, the organic matter content and its thermal maturity control porosity. The occurrence of solid bitumen in the rocks from these formations reduces samples’ mesoporosity because of the pore-clogging effect. In contrast, in the Pasłęk and Prabuty Formations, there is low organic matter content and specific surface area and the volume of mesopores increase with clay minerals content. In the Pelplin mudstones, there are no prevailing factors controlling porosity. Finally, we suggest that a combination of SEM image analysis and dual liquid porosity (DLP) measurements is a powerful method to assess porosity available for petroleum flow in mudstones.

Automated identification and quantification of tire wear particles (TWP) in airborne dust: SEM/EDX single particle analysis coupled to a machine learning classifier

The share of non-exhaust particles, including tire wear particles (TWP), within the airborne dust and particularly within PM10 has increased in recent years due to a significant reduction of other particles including exhaust road traffic emissions. However, the quantification of TWP is a demanding task due to the non-specificity of tracers, and the fact that they are commonly contained in analytically challenging low concentrations (e.g. Zn, styrene, 1,3-butadiene, vinylcyclohexene). This difficulty is amplified by the chemical and morpho-textural heterogeneity of TWP resulting from the interaction between the tires and the road surface. In contrast to bulk techniques, automated single particle SEM/EDX analysis can benefit from the ubiquitous heterogeneity of environmental TWP as a diagnostic criterion for their identification and quantification. For this purpose, we follow a machine-learning (ML) approach that makes use of an extensive number (67) of morphological, textural (backscatter-signal based) and chemical descriptors to differentiate environmental particles into the following classes: TWP, metals, minerals and biogenic/organic. We present a ML-based model developed to classify airborne samples (trained by >100,000 environmental particles including 6841 TWP), and its application within a one-year monitoring campaign at two Swiss sites. In this study, the mass concentrations of TWP in the airborne fractions PM80-10, PM10-2.5 and PM2.5-1 were determined. Furthermore, the particle size distribution and shape characteristics of 5621 TWP were evaluated. A cut through a TWP by means of FIB-SEM evidences that the mineral and metal particles typically found in TWP are not only present on the particle surface but also throughout the complete TWP volume. At the urban background site, the annual average mass fraction of TWP and micro-rubber in PM10 was 1.8% (0.28 μg/m3) and 0.9%, respectively. At the urban kerbside site, the corresponding values were 6 times higher amounting to 10.5% (2.24 μg/m3) for TWP, and 5.0% for micro-rubber.

Formation and Structure of Sulfide Deposits on Carbon Steel Under Free Corrosion Potential

The corrosion of alloy materials in the H2S environment has considerably limited the growth of oilfield manufacturing. The sour corrosion of iron has frequently been studied, and steel corrosion under the H2S scheme has been investigated. Many parameters affect the corrosion of carbon steel (CS) in the H2S natural environment, including a concentration of H2S, pH, and the temperature, which has significant impacts on the electrochemical responses of the bare metal surface, the formation, and the nature of the created sulfide scale. The latter could be either protective or nonprotective, depending on the formation conditions. This work presents a full experimental investigation for the initial corrosion events of iron/steel at the free corrosion potential for different periods of time in H2S-saturated solutions of different temperatures where H2S/N2 gas was purged into the solutions. The structure, morphology, composition, depth, and ion-concentration of the sulfide film that is established on the pipeline CS (mild carbon steel) in an acidic sour solution was examined using different bulk and surface techniques, e.g., an optical microscope, scanning electron microscopy, and Raman spectroscopy.

Atmospheric pressure plasma engineered superhydrophilic CuO surfaces with enhanced catalytic activities

Cupric oxide (CuO) thin film has found widespread application as a low-cost, earth-abundant material for electro and photo catalytic applications. High surface wettability is a key factor to achieve enhanced efficiency in these catalytic applications. Here, we report a fast and environment friendly route to fabricate super hydrophilic CuO thin films using a low power (5–10 W) atmospheric pressure plasma jet (APPJ). With APPJ treatment for 5 min, the CuO surface transforms from hydrophobic to super-hydrophilic with threefold increase in catalytic activity. The electrodes were extensively characterized using various bulk and surface-sensitive techniques. APPJ introduces anisotropy in the crystal structure and creates unique three-dimensional surface morphology with distinct surface chemical and electronic features. Interestingly, presence of oxygen in the plasma was found to be critical for the enhanced activities and the activity decreased when the functionalised with nitrogen plasma. Oxygen plasma functionalisation of CuO electrodes resulted in a 130 mV reduction in the onset potential for oxygen evolution reaction along with enhanced current density, 10 mA cm−2 against 3 mA cm−2 at 1 V vs Saturated Calomel Electrode in 0.1 M KOH without iR compensation. Importantly, without introducing any external dopants the work function could be decreased by 80 mV. Moreover, the treated films exhibited a higher rate of photo degradation (0.0283 min−1 compared to 0.0139 min−1) of Methylene Blue and phenol indicating efficient charge separation. This work presents the potential of APPJ functionalisation of CuO surface to boost the activity of other thin film catalyst materials and solutions processed systems.

Performance-limiting factors of graphite in sulfide-based all-solid-state lithium-ion batteries

A suite of bulk and surface analytical techniques was applied to shed light on the factors limiting fast cycling of composite graphite electrodes in all-solid-state cells based on sulfide electrolytes 0.75Li2S-0.25P2S5 (LPS) and 0.3LiI-0.7(0.75Li2S-0.25P2S5). Cracks in the composite electrodes and poor percolation of the ionic conducting particles were identified by both scanning electron microscopy and X-ray tomography and the slow kinetics during lithiation (limiting practical specific charge at rates >C/10, at geometrical current densities >120 μA cm−2) was monitored by operando X-ray diffraction and supported by Raman microscopy. Operando X-ray photoelectron spectroscopy and X-ray absorption spectroscopy detected the formation of Li2S and LixP at the interface between LPS and graphite, both compounds increasing the interfacial resistance. Despite the kinetic limitations, excellent long-term cycling performance is demonstrated at C/20 rate (at current density of about 60 μA cm−2), revealing slow self-passivation processes at the sulfide/graphite interface which stabilizes after approximately 200 full cycles.