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Polarization-sensitive Fourier ptychographic microscopy (ps-FPM) combines polarized light microscopy with Fourier ptychographic microscopy to image birefringent samples in high-resolution over a large field of view. Measurement of the anisotropy properties allows the samples to be viewed with greater contrast and to distinguish between sample regions that would otherwise be indistinguishable. In this work, ps-FPM is used to image birefringent petrographic thin sections to view the different crystal domains and to distinguish between the different minerals in the rock sample, a requirement for crystal domain classification and mineral identification. The system reported here achieves a resolution of 1.5 μm with a FOV of 9 mm 2 , far superior to traditional petrographic microscopes.

The findings of an extensive experimental research study on the usage of nano-sized cement powder and other additives combined to form cement–fine-aggregate matrices are discussed in this work. In the laboratory, dry and wet methods were used to create nano-sized cements. The influence of these nano-sized cements, nano-silica fumes, and nano-fly ash in different proportions was studied to the evaluate the engineering properties of the cement–fine-aggregate matrices concerning normal-sized, commercially available cement. The composites produced with modified cement–fine-aggregate matrices were subjected to microscopic-scale analyses using a petrographic microscope, a Scanning Electron Microscope (SEM), and a Transmission Electron Microscope (TEM). These studies unravelled the placement and behaviour of additives in controlling the engineering properties of the mix. The test results indicated that nano-cement and nano-sized particles improved the engineering properties of the hardened cement matrix. The wet-ground nano-cement showed the best result, 40 MPa 28th-day compressive strength, without mixing any additive compared with ordinary and dry-ground cements. The mix containing 50:50 normal and wet-ground cement exhibited 37.20 MPa 28th-day compressive strength. All other mixes with nano-sized dry cement, silica fume, and fly ash with different permutations and combinations gave better results than the normal-cement–fine-aggregate mix. The petrographic studies and the Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) analyses further validated the above findings. Statistical analyses and techniques such as correlation and stepwise multiple regression analysis were conducted to compose a predictive equation to calculate the 28th-day compressive strength. In addition to these methods, a repeated measures Analysis of Variance (ANOVA) was also implemented to analyse the statistically significant differences among three differently timed strength readings.

Sisal fiber exhibits a fibrous and porous structure with significant surface roughness, making it highly suitable for storing phase change materials (PCMs). Its intricate morphology further aids in mitigating the risk of PCM leakage. This research successfully employs vacuum adsorption to encapsulate paraffin within sisal fiber, yielding a potentially cost-effective, durable, and environmentally friendly phase change energy storage medium. A systematic investigation was carried out to evaluate the effects of sisal-to-paraffin mass ratio, fiber length, vacuum level, and negative pressure duration on the loading rate of paraffin. The experimental results demonstrate that a paraffin loading rate of 8 wt% can be achieved by subjecting a 3 mm sisal fiber to vacuum adsorption with 16 wt% paraffin for 1 h at −0.1 MPa. Through the utilization of nano-CT imaging enhancement technology, along with petrographic microscopy, this study elucidates the mechanism underlying paraffin storage within sisal fiber during vacuum adsorption. The observations reveal that a substantial portion of paraffin is primarily stored within the pores of the fiber, while a smaller quantity is firmly adsorbed onto its surface, thus yielding a durable phase change energy storage medium. The research findings contribute to both the theoretical foundations and the available practical guidance for the fabrication and implementation of paraffin/sisal fiber composite phase change energy storage mediums.

Sodalite is a common feldspathoid in alkaline systems, with some varieties exhibiting notable fluorescence due to impurity activators. This study reports the first documented occurrence and characterization of fluorescent sodalite from the classic Ditrău Alkaline Massif, Romania, where its optical properties were previously undescribed. Sodalite-bearing syenite samples from different perimeters of the massif were investigated using macroscopic UV fluorescence, petrographic microscopy, and vibrational spectroscopy (Raman and FT-IR). The sodalite occurs as a late-stage, interstitial and poikilitic mineral, often associated with alteration to cancrinite. Under long-wave UV (365 nm) light, it exhibits spatially variable fluorescence, from absent in parts of the western Prişca perimeter to strong, uniform orange in the eastern Aurora perimeter. Raman and FT-IR spectroscopy confirmed the mineral’s identity and revealed subtle spectral variations, particularly the presence of a minor cancrinite component in some analyses. The vibrant orange fluorescence is consistent with activation by disulfide radical anion (S2·−) activators, formed in the sulfur- and chlorine-rich late-stage fluids characteristic of the massif’s evolution. The geographic variation in fluorescence intensity serves as a potential indicator of the geochemical heterogeneity of these fluids across the massif, linking the strongest fluorescence to the most evolved portions of the igneous complex. This finding opens a new avenue for using fluorescence as a tool for petrogenetic investigation in this classic locality.

This review synthesizes the corpus of archaeometric and analytical investigations focused on mortar-based materials, including wall paintings, plasters, and concrete, in the Roman Regio X and neighboring territories of northeastern Italy from the mid-1970s to the present. Organized into three principal categories—wall paintings and pigments, structural and foundational mortars, and flooring preparations—the analysis highlights the main methodological advances and progress in petrographic microscopy, mineralogical analysis, and mechanical testing of ancient mortars. Despite extensive case studies, the review identifies a critical need for systematic, statistically robust, and chronologically anchored datasets to fully reconstruct socio-economic and technological landscapes of this provincial region. This work offers a programmatic research agenda aimed at bridging current gaps and fostering integrated understandings of ancient construction technologies in northern Italy. The full forms of the abbreviations used throughout the text to describe the analytical equipment are provided at the end of the document in the “Abbreviations” section.

The Kavokta deposit of the dolomite type nephrite is located in the Middle Vitim mountain country, Russia (Russian Federation). The deposit area is composed of granite of the Late Paleozoic Vitimkan complex. The granite contains complex shape blocks of Lower Proterozoic rocks. They are represented by metasandstone, crystalline schist, amphibolite, and dolomite marble. The calcite–tremolite and epidote–tremolite skarns were formed on the contact of dolomite and amphibolite. Calcite–tremolite skarn contains nephrite bodies. The mineral composition of 16 core samples obtained during the geological exploration conducted by JSC “Transbaikal Mining Enterprise” within Vein 1 of Prozrachny site has been studied in thin sections using a petrographic microscope, and in polished sections using a scanning electron microscope, with an energy-dispersive microanalysis system. Twenty-five minerals have been identified. They have been attributed to relict, metasomatic associations of the pre-nephrite and nephrite stages and hydrothermal and secondary associations. The intensity of the nephrite’s green color is explained by the Fe admixture in tremolite, and the black color is explained by its transition to actinolite in the areas of contact with epidote–tremolite skarn after amphibolite. In the formation and alteration of nephrite, dolomite is replaced by diopside, diopside by tremolite, prismatic tremolite by tangled fibrous tremolite, and tremolite by chlorite. Granite provides heat for metasomatism. Participation of amphibolite in the nephrite formation determines the variety of nephrite colors. The role of metamorphism is reduced to tectonic fragmentation facilitating fluid penetration; stress provides a tangled fibrous cryptocrystalline texture.

In the present work, the cement and/or matrix, pores, and grains present in sandstones were quantified by telepetrography. The selected sandstones come from the superficial formations of Ivorian onshore basin and the deep formations of offshore basin. A total of six sandstones, three from each part of Ivorian basin, were analyzed. The tele-petrographic analysis consisted of processing the images of these sandstones taken under the natural light from petrographic microscope to the R software using the «terra» package. The results show that the quantification of sandstone components depends on the magnification of the microscope image, the grain size, and the sorting. At low and medium magnifications, a small number of images per rock is sufficient to evaluate the proportions of the components. At high magnifications, however, a large number of images are required as they tend to overestimate the proportions of grains at the expense of other components (porosity, cement, matrix) if the grains have a poorly sorted. The presence of phenocrysts accentuates these variations. However, if the sandstones have a well sorting, the proportions of components hardly vary from one image to another, whatever the magnification. The density curves and histograms reveal that the number of components on these curves depends on the proportions; the higher the proportion of a component the better it is represented. Low proportions remain invisible on the density curves. Remote sensing is therefore promising for the evaluation of the petrophysical properties of reservoir rocks.

Lake sediments on the Tibetan Plateau are important natural archives for studying past climate and environment changes. A precise sediment core chronology is a fundamental prerequisite for reconstructing past climate and environment changes. However, radiocarbon dates on bulk carbon in lake sediment cores are subject to “old carbon” reservoir effects, which can cause problems when trying to establish depth-age relations for sediment cores, especially those from the Tibetan Plateau (TP). Here we present a varve chronology that spans the last ~ 2000 years, from Jiang Co, on the central TP. Clastic-biogenic varves in Jiang Co sediments are comprised of two laminae, a coarse-grain and a fine-grain layer, observed by petrographic microscope and Electron Probe Micro Analyzer. The varve chronology is supported by 210Pb and 137Cs dating and was used to estimate the radiocarbon reservoir ages for the past ~ 2000 years. The thickness percentage of the coarse-grain layer within a single varve was used as a proxy for summer precipitation amount, as coarse grains are transported mainly by runoff. During the past 2000 years, the precipitation record inferred from Jiang Co sediments shows centennial-scale fluctuations that are consistent with other records from the region. The varve chronology from Jiang Co provided a valuable opportunity to estimate the “old carbon” reservoir effect in Jiang Co and reconstruct past precipitation on the Tibetan Plateau.

Several pottery sherds from the Svilengrad-Brantiite site, Bulgaria, were mineralogically and petrographically analyzed. The aim was to add information to the very scarce material data available for Early Bronze Age pottery in the southeastern Thrace plain, Bulgaria, in order to examine a possible raw-material source of the pottery. The characterization techniques applied were optical microscopy (OM), petrographic microscopy (PM), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS), X-ray fluorescence (XRF) spectroscopy, and X-ray diffraction (XRD). The pottery samples consisted of two typological groups: a local-made type and a cord-impressed decoration type influenced by foreign cultures. All of the samples were produced from fine clay pastes that had a quite similar composition, with abundant mineral grains of similar mineral composition and fragments of metamorphic and granitic rocks. The chemical compositions of each mineral in the grains and fragments were almost identical, and consistent with those from metamorphic and granitic rocks from the Sakar-Strandja Mountains near the study site. The clay paste compositions corresponded to those of illite/smectite mixed-layer clay minerals or mixtures of illite and smectite, and the clay-mineral species were consistent with those in Miocene–Pleistocene or Holocene sediments surrounding the site.

A petrographic analysis was conducted to identify the mineral contents containing in the rock samples collected at study area located in Lojing, Gua Musang. The geology of the study area consists of metasedimentary rocks. There are six hand specimens collected and analysed using petrographic microscope. The limestone and carbonate rock is found at the study area. It has been subjected to some stress to such an extent that some of the grain boundaries have been modified by pervasive pressure solution of stylolites. Pressure solution is the process whereby this limestone has undergone selective dissolution to the extent that the grain boundaries were modified into thin dark n sutured seams. The rocks contain also microcrystalline to cryptocrystalline silica clasts which occur dispersed throughout the matrix. The petrographic analysis results show that the minerals contain in the six rock samples are micrite, bioclast, microspars, deformed quartz, K-feldspar, lithic and clayey carbonate lithic. The major minerals contained in the rocks are micrite and bioclast.