Jim Buckman

Conventional pretreatment methods used in metallic textile printing are associated with high water consumption, intensive chemical use, and significant wastewater generation. This study investigates low-pressure air plasma treatment as an environmentally sustainable pretreatment strategy for metallic pigment printing on cotton fabrics. Gray and bleached woven cotton fabrics were exposed to air plasma at 200 W for 3 and 5 min before screen printing with gold- and silver-based metallic pigments. The effects of plasma treatment on fabric surface chemistry and morphology were evaluated using contact angle measurements, attenuated total reflectance-Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). Plasma treatment significantly increased the hydrophilicity of both cotton substrates, reducing liquid penetration time from 61 s to less than 10 s for bleached cotton and from more than 20 min to 6 s for gray cotton. ATR-FTIR and XPS analyses confirmed the formation of oxygen-containing functional groups, whereas SEM images showed surface etching and increased roughness that enhanced pigment anchorage. The improved surface functionality translated into superior metallic print performance. Plasma-treated fabrics exhibited enhanced color fastness to washing, rubbing, perspiration, and light compared with untreated fabrics. The greatest improvement was observed after 5 min of plasma exposure, particularly for gold pigment prints. However, SEM analysis revealed that prolonged exposure (5 min) may lead to increased surface erosion, highlighting the need for careful optimization to balance surface activation with the preservation of fiber integrity. Ultraviolet-visible spectroscopy of wash effluents demonstrated lower pigment release from plasma-treated samples, confirming improved pigment retention and reduced wastewater contamination. The results demonstrate that low-pressure air plasma treatment can replace conventional wet chemical pretreatments for metallic textile printing, offering substantial reductions in water use, chemical consumption, and pigment discharge. The approach provides a practical route toward cleaner and more sustainable textile production, particularly for emerging textile industries.

The calcareous tubes of the annelid worm Ditrupa are known from the Eocene to present-day marine settings. It has a distinctive and unique outer layer comprising regularly ridged prismatic fabric (RRP), and a more chaotic inner layer of semi-oriented, needle-to-thread-like calcite, simple preferentially orientated prismatic (SPOP) fabric. We use electron backscattered diffraction (EBSD) analysis in conjunction with scanning electron microscopy (SEM) backscattered (BSE) imaging and energy dispersive X-ray (EDX) mapping in the study of the tube structure of (?)Eocene Ditrupa sp. The fabric of both layers can often be observed even within the older fossil materials. EBSD Inverse Pole Figures and pole figure plots show that the crystallographic c-axis is orientated parallel to both of the elongate calcite crystals of the two fabric layers, although orientation between the two layers is perpendicular to each other. The crystals and c-axis of the RRP fabric is approximately perpendicular to the outer tube margin, while those in the SPOP fabric are more distributed with an orientation parallel to the tube circumference. The current work confirms the single crystal origin of RRP fabric crystals and indicates that these grew incrementally and were likely controlled by an organic framework. The inner layer fabric is also shown to be unique to Ditrupa, and although it has elements similar to lamello-fibrillar (LF) and irregular orientated prismatic (IOP) fabrics, should be assigned to simple preferentially orientated prismatic (SPOP) fabric previously noted from Ditrupa bartonensis. Given the range of unusual features associated with the latter fabric, it may also at least in part be controlled through an in situ organic framework. Therefore, both layers of the tube of Ditrupa may be unique amongst the annelids, as well as being organic framework controlled or influenced.

Caprock integrity is a critical requirement for the safe and long-term geological storage of CO ₂ , yet its assessment remains challenging due to extremely low permeability, strong mineralogical heterogeneity and the limited availability of representative core samples. In particular, the influence of petrological properties and mineral composition on caprock porosity and permeability is still poorly constrained, especially where evaluations rely increasingly on drill cuttings rather than intact cores. This study addresses these challenges by systematically investigating the relationships between mineralogy, pore structure, porosity, and permeability in a siltstone caprock overlying a carbonate reservoir in the offshore Sarawak Basin, Malaysia. An integrated experimental workflow combining X-ray diffraction, scanning electron microscopy, particle size analysis, low-pressure gas sorption, mercury intrusion capillary pressure, nuclear magnetic resonance, helium pycnometry and unsteady-state pulse decay permeametry was applied to both core plugs and drill cuttings. Two distinct caprock facies (Seal A and Seal B) were identified, differentiated primarily by clay and carbonate content, grain size distribution, and pore throat characteristics. Results show that clay-rich, well-cemented microporous to nanoporous fabrics strongly control permeability, resulting in nanoDarcy-scale values under in situ stress conditions despite moderate total porosity. Porosity and permeability estimates derived from drill cuttings consistently exceed those from confined core measurements, highlighting the need for method- and stress-dependent corrections when cuttings are used for seal evaluation. The novelty of this work lies in quantitatively linking mineralogical and petrological attributes to multi-method porosity–permeability measurements while critically evaluating the reliability of drill cuttings as proxies for core-based caprock characterization. The combined low permeability and high capillary entry pressures indicate that the studied caprock can safely retain CO ₂ columns exceeding the structural closure of the reservoir. These findings demonstrate a robust, cost-effective framework for caprock assessment in data-limited settings and provide transferable insights for CO ₂ , hydrogen and gas storage applications.

Existing porosity-permeability models predominantly rely on bulk and large-scale properties, often neglecting multiple length scales, particularly the nano-to-micron scale. Such multi-scale pore types are inherent to carbonate rocks. Nano-scale imaging is crucial for interpreting the structure of microporosity, which consists of micropores that contribute up to 96% of the total pore size distribution in carbonates. This study aims to characterise the pore space of complex carbonate rocks across multiple scales using multiscale imaging techniques and establish a more accurate porosity-permeability relationship for CO2 storage sites. Multiscale X-ray and SEM tomography were performed on different sample sizes. 3D images were acquired using X-ray micro-CT at low resolution, followed by high-resolution 3D imaging of a sub-plug region of interest and mini-plug samples. Qualitative image processing was conducted to segment into distinct phases. Subsequent quantitative image processing involved pore space analyses, subvolume extraction and numerical pore-scale simulations. The porosity-permeability relationships were upscaled from the nano-scale to the meso-scale using the Darcy-Brinkman-Stokes equation. The image-based upscaling models were then applied and compared with the petrophysical-derived models. This study reveals the presence of interconnected micropores within the rock matrix during carbonate rock formation, highlighting the importance of micropores in enhancing the porosity-permeability relationship. By employing an image-based protocol that enables multi-resolution imaging of the same sample, the complex pore structures and fluid dynamics within carbonate rocks can be revealed, thereby enhancing the accuracy of CO2 injection models and improving storage efficiency. Consequently, the study can be utilised in upscaling routines to provide critical insights into the feasibility and optimisation of geological CO2 storage.

In underground hydrogen storage operations, reservoir rocks often experience periodic pore pressure fluctuations due to annual or more frequent gas extraction and injection cycles. These fluctuations subject the reservoir rocks to cyclic effective stress changes, causing their mechanical and transport behaviors to differ from those under static conditions. However, understanding how porous rocks react to cyclic loading conditions is still limited. To bridge previous research gaps, cyclic loading tests were conducted on Castlegate and St Bees Sandstone, with applied stress amplitudes ranging from 70 to 90% of their monotonic peak strength. This experimental approach was designed to replicate the in situ stress conditions experienced by reservoir rocks during gas operations. Concurrently, we utilised the steady-state method to measure permeability changes under cyclic loading. By comparing the micro-CT features of the sandstones before and after cyclic loading tests, we quantitatively analysed the microscopic mechanisms driving these alterations in sandstone samples. Our results show that under cyclic loading conditions, the inelastic axial strain and Young’s Modulus initially increase for both sandstones, with the most significant changes occurring within the 1st cycle, followed by a trend towards stability. Permeability decreases with increasing stress and loading cycles. For the Castlegate Sandstone, elevated confining pressure intensified permeability loss, while in St Bees Sandstone, high confining pressure resulted in less permeability loss compared to low confining pressure, which was related to shear band development. Microstructural analysis showed grain movement, rotation, and rearrangement in Castlegate Sandstone under external forces, leading to pore/throat compression and reduced porosity/permeability. In contrast, St Bees Sandstone microstructure changes under low stress involved grain cracking from shear dilatancy, increasing porosity but blocking throats, complicating pore structure, then reducing permeability. Under high confining pressure, the strength of St Bees Sandstone rose without sufficient differential stress for shear dilatancy. Decreased permeability and pore volume were linked to compaction-dominated deformation.

The acquisition of three-dimensional (3D) stereo paired images by scanning electron microscopy (SEM) typically requires the tilting of the SEM stage about the eucentric working distance, which is typically set at 10 mm working distance (WD).

An understanding of the textures (grain size, grain shape, porosity, etc.), composition (mineralogy), and distribution of constituent components of geological materials such as carbonate and siliciclastic sedimentary rocks is essential in their classification, interpretation, and significance in terms of their geomechanical strength and liquid/gas storage potential. In terms of scanning electron microscopy (SEM), this is limited to relatively flat areas of selected rough surfaces, or the analysis of polished thin sections. Here, we illustrate a new technique that can image large areas of the external surface of mini-cores (approximately 10 mm or smaller in diameter) drilled from carbonate and siliciclastic rock samples. The technique utilises a specially developed horizontal rotation stage within an SEM and allows the collection of high-resolution images that can be reconstructed into realistic surface representations of the mini-core surfaces. Elemental data (representative of mineralogy) can also be added using a combined backscattered electron and X-ray (BEX) detector. Currently, these reconstructions can be used as a useful tool for the analysis of both carbonate and siliciclastic geological materials. Further work may allow such reconstructions to aid in the improvement of resolution in micro-CT scans and the direct identification of mineral phases within such scans.

The aim of the current paper is to demonstrate the use of a novel prototype horizontal rotation stage, within a scanning electron microscope (SEM). Here we utilise sedimentary rock chips and grains, with images collected every 10 ° of rotation, to produce a continuous overlapping field of view 360° montage. The same procedure can also be used to collect elemental X‐ray maps. The collected images and maps can be simply combined into an image stack and saved as a movie format of the rotating specimen through 360°. More significantly, individual images and elemental maps can be reconstructed using photogrammetry imaging software, producing three‐dimensional (3D) models with mesh worked surfaces and rendered texture (colour or greyscale) based on SEM image and X‐ray data. This produces photorealistic smoothly transitioning movies with 360° fields of view around each object and can also be saved for stereo‐viewing using a virtual reality (VR) headset. This new technique generates highly detailed information on the 3D structural and compositional relationships between components at the submicron to millimetre scale. The technique has widespread applications, including imaging other geological materials, biological mineralised tests and material science specimens such as metals, ceramics and building materials.

We tested a scanning electron microscope equipped with the newly developed Unity-BEX detector (SEM-BEX) system to study thirty-nine samples of the testate amoeba Difflugia. This produces fast single-scan backscattered (BSE) and combined elemental X-ray maps of selected areas, resulting in high-resolution data-rich composite colour X-ray and combined BSE maps. Using a suitably user-defined elemental X-ray colour palette, minerals such as orthoclase, albite, quartz and mica were highlighted in blue, purple, magenta and green, respectively. Imaging was faster than comparable standard energy dispersive X-ray (EDX) analysis, of high quality, and did not suffer from problems associated with the analysis of rough surfaces by EDX, such as shadowing effects or working distance versus X-ray yield artifacts. In addition, we utilised the AZtecMatch v.6.1 software package to test its utility in identifying the mineral phases present on the Difflugia tests. Significantly, it was able to identify many minerals present but would require some further development due to the small size/thinness of many of the minerals analysed. The latter would also be further improved by the development of a bespoke mineral library based on actual collected X-ray data rather than based simply on stoichiometry. The investigation illustrates that in the case of the current material, minerals are preferentially selected and arranged on the test based upon their mineralogy and size, and likely upon inherent properties such as structural strength/flexibility and specific gravity. As with previous studies, mineral usage is ultimately controlled by source availability and therefore may be of limited taxonomic significance, although of value in areas such as palaeoenvironmental reconstruction.