Microanalytical Techniques Research Articles

Hydrothermal overprinting of the Li-rich strata deposited in the Mesoproterozoic Wumishan Formation, Hebei Province, North China

Lithium (Li), as a strategic critical metal, plays a pivotal role in the emerging energy landscape, particularly in the context of Li-ion batteries driving the new energy economy. Recently, Li-rich strata (with Li2O > 0.3 wt%) have been discovered in the Mesoproterozoic Wumishan Formation in Hebei Province, North China, suggesting a prospective Li reservoir. This study investigates these Li-rich strata using geochemical and in-situ micro-analytical techniques to explore the occurrence of Li and the formation mechanism of Li-host minerals, aiming for a comprehensive understanding of the supernormal enrichment of Li. The Li-rich samples are predominantly composed of dolomite and quartz, followed by clay minerals such as illite, interstratified illite–smectite (I/S), and chlorite, with minor amounts of K-feldspar, albite, biotite, calcite, baryte, fluorite and fluorapatite. In-situ analysis and 7Li NMR spectroscopy reveal that Li predominantly occupies the octahedral sites within the structures of authigenic illite and I/S, while its absence in clastic illite, clastic chlorite, unaltered K-feldspar, and dolomite. The presence of veined minerals (e.g., fluorite, baryte, and calcite) and a strong positive correlation between Li and F imply that post-depositional hydrothermal fluids have significantly contributed to the formation of Li-host minerals. The paragenesis of these minerals suggests that Li-bearing illite has formed through the hydrothermal alteration of K-feldspar. These Li-bearing illites subsequently transformed into Li-bearing I/S, consisting of illite-rich I/S and smectite-rich I/S, under continuous hydrothermal alteration. Lithium could have been leached from the surrounding carbonate rock and tuff through water–rock interaction and subsequently enriched by post-depositional hydrothermal fluids in specific regions, leading to mineralization. These findings provide valuable insights for targeting exploration of this promising Li resource.

Semi-quantitative μLIBS mapping of germanium diffusion between metal and silicate during planetary core–mantle segregation

Understanding the distribution of elements between the cores and mantles of planetary bodies is essential for elucidating the geological and geochemical processes operating during their formation. Because the semi-metallic element Ge shows complex siderophile, chalcophile, and lithophile properties, it is particularly significant for investigating core–mantle segregation and ore deposit formation. Recent advancements in in situ microanalysis techniques, such as μLIBS, have enabled high-resolution elemental mapping of Ge and other trace elements.This study explores the application of μLIBS imaging to investigate the high-temperature/high-pressure distribution of Ge between metallic and silicate matrices analogous to planetary cores and mantles. By cross-calibrating the μLIBS intensities with electron microprobe profile analyses carried out on piston cylinder experimental samples, we produced semi-quantitative Ge maps from which we extracted Ge concentration profiles to assess Ge diffusion from the silicate to the metal. We determined, for the first time, the diffusion coefficient of Ge between metal and silicate to be D(Ge)metal = 4.03E−13 ± 3.6E−14 m2/s at 1 GPa and 1350 °C. Our results demonstrate the capability and efficiency of μLIBS for providing detailed, high-resolution (15 μm) trace element concentration data at few ppm levels, offering a time- and cost-effective alternative to conventional techniques.These findings bring insights on planetesimal differentiation and on chemical exchanges between metal and silicate phases in a magma ocean and between two different metal phases occurring at the bottom of the magma ocean during planetesimal formation.

High-throughput determination of interdiffusivity and atomic mobilities in bcc Ti–Cr–Mo alloys

A comprehensive understanding of the diffusion coefficients and atomic mobilities in the Ti–Cr–Mo system is crucial for establishing an atomic mobility database for titanium-based high-strength titanium alloys. In the present work, nine sets of solid/solid diffusion couples were prepared and measured in bcc Ti–Cr–Mo alloys, with the temperatures ranging from 1373 to 1473 K. Scanning electron microscopy (SEM), and Electro Probe Micro-Analysis (EPMA) techniques were used to respectively test its microstructure and composition distance. The diffusion coefficients in bcc Ti–Cr–Mo alloys were determined using the Matano-Kirkaldy method and numerical inverse method respectively. The diffusion coefficients obtained from the above two methods exhibit good consistency. The atomic mobility parameters for the Ti–Cr–Mo systems were provided with the assistance of HitDIC software. A three-dimensional plot of interdiffusivities was generated for chromium and molybdenum contents ranging from 0 to 20 mol % and 0–14 mol %. Moreover, the application of the Arrhenius equation enabled the determination of changes in frequency factors and activation energies concerning temperature and composition.

Noninvasive Multitechnique Analysis of Baroque Amber Artworks From Gdansk: The Benefits of Using Raman Spectroscopy

ABSTRACTThe multidisciplinary, noninvasive analysis of baroque amber artworks is part of a research project that deals with the most valuable objects from the Museum of Gdansk (Poland). The two most interesting objects will be presented here: a Baroque Gdansk wardrobe‐shaped amber cabinet (made by Johann Georg Zernebach, Gdansk, 1724) and a crucifix (Gdansk, 17th century). Macro‐ (UV, IR, and X‐radiography) and micro‐ (XRF and Raman spectroscopy) analytical methods were applied to reveal traces of old conservation treatments and uncover the techniques of the 17th and 18th century amber masters. UV photography shows the differences between the amber plates that are not so easily detected under visible light, while XRF spectrometry detects elements atypical for amber objects, suggesting previous conservation treatments. Confocal Raman measurements, especially Raman depth profiling, were performed for the amber artworks and allowed to detect areas of previous conservation treatments. Single‐point scans were collected from the surface (0 μm) to a depth of −200 μm, with a step of 50 μm. The results allowed us to identify three different types of zones: where the amber was preserved without any protective layer, places where the amber was covered with a thin layer of a protective substance, and places where amber elements were compensated for loss using a binding agent and filler. The presented project allowed the development of a comprehensive methodology for the analysis of amber objects, especially to optimize the capabilities of confocal Raman microscopy. The combination of macro‐ and microanalytical techniques made it possible to obtain a broad overview of such complex artworks while optimizing the time and effort spent on the investigations.

Germanium distribution in Mississippi Valley-Type systems from sulfide deposition to oxidative weathering: A perspective from Fule Pb-Zn(-Ge) deposit, South China

Abstract Germanium (Ge) is a critical raw material for emerging high-tech and green industries, resulting in considerable recent interest in understanding its distribution and geochemical behavior in ore deposits. In this contribution, the distribution of Ge and related trace elements in the Fule Pb-Zn(-Ge) deposit, South China, is investigated to reveal the distribution of Ge in the hydrothermal ores and during sulfide weathering, using multiple microanalytical techniques, including scanning electron microscopy, electron probe microanalysis and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). In the Fule MVT deposit, sphalerite (ZnS) is the most significant Ge-carrier relative to other sulfides, though the five recognized textural types of sphalerite display progressive depletion in Ge from the first sphalerite generation to the late one. In the early stage, sphalerite with fine-grained chalcopyrite inclusions has the highest Ge concentrations, probably accounting for a significant proportion of the total Ge. We interpret that high Ge concentrations in the early sphalerite may be attributable to high Cu activity in the mineralizing fluids. During oxidative weathering, Ge was redistributed from its original host, sphalerite, to the weathering product willemite (Zn2SiO4) rather than smithsonite (ZnCO3), with high levels of Ge (up to 448 μg/g) present in the willemite. The formation of abundant willemite largely prevents the dispersion of Ge during weathering. In principle, willemite-hosted Ge should be fully recoverable, and the Zn-silicate ores may, therefore, be a potential target to meet future demand. This study provides new information on how Ge behaves from sulfide- to weathering-stage in MVT systems, which directly impacts Ge mobility and deportment changes and the development of metal-lurgical strategies for Ge recovery.

An Approach to Accurately Identifying Binders in Historic Mortars by the Combination of Microscopic and Microanalytical Techniques

Mortars are among the most important materials in building construction. They are generally obtained by mixing aggregates with an inorganic binder. The identification of mortar constituents, particularly the binder type in historic buildings, is one of the essential aspects of building conservation, considering that the new conservation materials must be chemically, mechanically, and physically compatible with the old masonries. Among other techniques used to characterise binders, those related to optical and electronic microscopy are particularly important. Microscopy and combined techniques may be the key to this identification since the classic mineralogical and chemical-based identification approaches are not conclusive enough in investigating the types of hydraulic binders in mortars. This work presents an analysis procedure to identify mortar binders by combining EDS microanalysis and petrography. Mortar samples of known composition were used as a reference for analyzing mortars from historic buildings. The proposed methodology made it possible to identify the type of binder or a mixture of binders based on the identification of the binder features by petrography together with analysis of the chemical composition of the paste by X-ray microanalysis under a scanning electron microscope.

From Macro to Micro: Microscopic and Microanalytical Techniques in Museum Conservation Science

From Macro to Micro: Microscopic and Microanalytical Techniques in Museum Conservation Science

Experimental investigation on physical properties and early-stage strength of ultrafine fly ash-based geopolymer grouting material

The conventional cement grouting materials possess certain drawbacks that hinder their environmental compatibility. The utilization of geopolymer grouting materials with the raw material of fly ash is anticipated to serve as a proficient approach in mitigating the environmental problem caused by solid wastes. Consequently, this study employed ultrafine fly ash (UFA) and granulated blast furnace slag (GBFS) as composite base materials to fabricate a kind of novel geopolymer grouting material. The addition of 0.05 % − 0.2 wt% graphene oxide (GO) facilitated the preparation of this material, and the physical properties and early-stage strength were experimentally investigated. The micro-analysis was conducted using micro-analysis techniques, including Fourier transform infrared and energy dispersive X-ray spectroscopy, etc. The findings indicated that as the contents of GO and GBFS increased, the flowability slightly decreased; the addition of GBFS and GO can contribute to the elevation of viscosity; the initial and final setting times were decreased. The bleeding rate decreased and increased with increasing GO and GBFS contents. It was also found that the GO and GBFS were beneficial to increase the water retention rate. Furthermore, the inclusion of GO and GBFS significantly enhanced the early-stage compressive strength of the grouting material. The GO and GBFS contents of 0.1 % and 60 % resulted in the attainment of maximum compressive strength of samples, with the value of 15.89 MPa at the first day. The simultaneous utilization of GO and GBFS facilitates the generation of a greater quantity of calcium-alumina-silicate-hydrate gel, thereby substantially enhancing the initial compressive strength of grouting materials. The results of this study could provide valuable perceptions into the production of sustainable grouting materials with low carbon emissions and the recycling utilization of solid wastes.

Investigating nuisance dust complaints: Combining high frequency dust deposition records and source identification using integrated microanalytical techniques

While ducted dust emissions from industry are usually well regulated and controlled, fugitive dust emissions can be difficult to quantify or differentiate from off-site emissions, particularly where fugitive emissions are transient or intermittent. In this study, sources of nuisance dust were investigated using a novel dust deposition sampling methodology, followed by chemical and mineralogical analysis using optical microscopy, x-ray diffraction (XRD), scanning electron microscopy with energy dispersive x-ray spectrometry (SEM-EDS), and isotope ratio mass spectrometry analysis. Dust deposition over 24 h was collected on horizontally orientated 300 mm square glass panels at 6 sites in the region of interest. This method captured very small (<10 mg) masses of dust and could distinguish very small variations in dust deposition at different sites and on different days. Comparison samples collected from potential dust sources at a nearby lime manufacturing facility, and other potential fugitive dust sources in the region were differentiated using XRD mineralogy, visual appearance by optical microscopy and SEM-EDS analysis of individual particles. Comparison of selected dust samples to reference samples indicated most dust deposition at the study sites consisted of soil or sand. However, dust deposition at two sites was sometimes composed of a material that was similar in composition to lime that had been rehydrated to portlandite, but not yet fully carbonated to calcite. Subsequent analysis of δ13C and δ18O for selected dust samples from these two sites were consistent with rapid and recent carbonation of small particles in an alkaline environment, which could have occurred during the atmospheric release and transport of lime, and ruled out fugitive dust emission from lime stockpiles existing on site. Combining the information obtained from high frequency record of dust deposition with targeted mineralogical, isotopic and morphological examinations provided new insight into the source of fugitive dust emissions in this area.

Modern Muralists in the Spotlight: Technical and Material Characteristics of the 1946–1949 Mural Paintings by Almada Negreiros in Lisbon (Part1)

This paper presents the first insight into how Almada Negreiros, a key artist of the first generation of modernism in Portugal, created his mural painting masterpiece in the maritime station of Rocha do Conde de Óbidos in Lisbon. This set of six monumental mural paintings dates from 1946 to 1949 and is considered Almada’s artistic epitome. As part of the ALMADA project: Unveiling the mural painting art of Almada Negreiros, the murals are being analyzed from a technical and material perspective to understand his modus operandi and the material used. This is the first study of this nature carried out on site and in the laboratory using standard and more advanced imaging, non-invasive analysis, and microanalysis techniques. This article reports the results obtained with visual examination, technical photography in visible (Vis), visible raking (Vis-Rak), complemented by 2D and 3D optical microscopy (OM), scanning electron microscopy with energy-dispersive spectrometry (SEM-EDS), and Fourier transform infrared micro-spectroscopy (µ-FTIR) of the paint layers. The results show the similarities, differences, and technical difficulties that the painter may have had when working on the first, third, and presumably last mural to be painted. Vis-Rak light images were particularly useful in providing a clear idea of how the work progressed from top to bottom through large sections of plaster made with lime mortars. It also revealed an innovative pounced technique used by Almada Negreiros to transfer the drawings in full scale to the walls. Other technical characteristics highlighted by the analytical setup are the use of textured, opaque, and transparent paint layers. The structure of the paintings does not follow a rigid build-up from light to dark, showing that the artist freely adapted according to the motif represented. As far as the colour palette is concerned, Almada masterfully uses primary and complementary colours made with Fe-based pigments and with synthetic ultramarine blue, cadmium pigments, and emerald green.

Thermodynamic re-optimization of the CaO–SiO2 system integrated with experimental phase equilibria studies

CaO–SiO2 is the key system in ferrous and non-ferrous metallurgy, ceramic manufacture, cement production, and other applications. A number of discrepancies and gaps in knowledge has been identified and resolved since the last thermodynamic optimization of this system. This study reports new experimental phase equilibria data measured using recent advances in equilibration, sample quenching, and Electron Probe X-ray Microanalysis (EPMA) technique. An updated self-consistent set of thermodynamic model parameters is provided. Most importantly, these updates are integrated with a complete re-assessment of the 20-component Cu–Pb–Zn–Fe–Ca–Si–O–S–Al–Mg–Cr–Na–As–Sn–Sb–Bi–Ag–Au–Ni–Co system directly relevant to applications in the ferrous and non-ferrous metallurgical industries. To obtain a large single set of model parameters, significant advances were made in the computational approach, with a focus on simultaneous parallel optimization of binary and ternary model parameters using an experimental dataset combining binary, ternary, and multicomponent information. The Modified Quasichemical Formalism is used for the liquid slag phase. Thermodynamic properties of solid phases and liquid endmembers are completely revised following the recommendations for the third generation of CALPHAD databases. Other notable changes include the revision of the melting temperature of CaO, justified by extrapolations from the multicomponent systems, as well as a physically realistic heat capacity function for metastable SiO2 below the glass transition temperature. These updated properties expand the areas of application of the database to amorphous and partially crystallized slags at ambient temperatures, such as thermodynamics and kinetics of leaching of toxic elements in an aqueous environment. The fundamental limitations of the existing Modified Quasichemical Formalism are also discussed, along with strategies for addressing them.

Experimental Investigation of Phase Equilibria in the Al–Mo–Hf Ternary System at 400 °C and 600 °C

This study investigates the phase equilibria of the Al-Mo-Hf ternary system at 400 °C and 600 °C using X-ray diffraction (XRD) and electron probe microanalysis (EPMA/WDS) techniques. Seven three-phase and five two-phase regions were identified at 400 °C, while eight three-phase and four two-phase regions were identified at 600 °C. Despite variations in the solid solubility ranges of certain compounds, the distribution of phase zones in the isothermal cross-section remained consistent at both temperatures. Using the experimental results and logical deductions, isothermal cross-sections were constructed for the Al-Mo-Hf ternary system at 600 °C and 400 °C.

Comparative study on hydrogen embrittlement resistance in additive manufactured and forged austenitic stainless steel

In this work, the hydrogen embrittlement resistance of additively manufactured (AM) and conventionally manufactured (CM) Cr21Ni6Mn9N (21−6−9) stainless steels were comparatively investigated. The mechanical properties and microstructure evolution of both AM and CM conditions were studied using slow strain rate tensile tests and microanalytical techniques such as scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and electron channeling contrast imaging (ECCI). The results indicated that compared to the CM condition, the AM stainless steel demonstrated enhanced resistance to hydrogen embrittlement, coupled with a reduction in plasticity loss. The primary factor contributing to this resistance was identified as an increased occurrence of deformation twinning in both steels after hydrogen charging. The superior resistance observed in the AM stainless steel was attributed to the occurrence of higher-density deformation twinning and microbands.

Synthesis, spectroscopic, biological and structural characterizations for the gold(III), platinum(IV), and Ruthenium(III) ceftriaxone drug complexes

Three new metal complexes of ceftriaxone (cef), incorporating platinum(IV), gold(III), and ruthenium(III), were prepared. The complexes were prepared using a 1:2 molar ratio between ceftriaxone sodium salt (Na2cef) to AuCl3, PtCl4, and RuCl3 salts in methanol solvent. The as-synthesized complexes were characterized using microanalytical techniques for C, H, N, and S elements, magnetic and molar conductance measurements, as well as spectroscopic methods including FTIR, 1H NMR, and UV-Vis. The shape, morphology and size calculations have been examined using SEM, TEM, and X-ray diffraction data. The cef complexes were six-coordinate systems possessing a distorted octahedral geometry. Through the oxygen of both triazine and carboxylate moieties with the chemical formulae [Au(cef)2(Cl)(H2O)] (I), [Pt(cef)2(Cl)2] (II), and [Ru(cef)2(Cl)(H2O)] (III) the antibiotic cef acts as a bidentate ligand towards three metal ions. The newly created complexes demonstrated antibacterial activity showing efficacy in comparison to the cef sodium ligands. In vitro, antibacterial assays against specific microorganisms were evaluated to assess the antibacterial activities of the complexes. Cytotoxicity assays for cef complexes were conducted for HepG-2 and MCF-7 cell lines, representing human hepatocellular carcinoma and breast cancer, respectively. A value of 22.4 g and 26.2 g for 50% inhibitory concentration (IC50), respectively, for HepG-2 and MCF-7 were obtained for [Ru(cef)2(Cl)(H2O)] (III). KEY WORDS: Ceftriaxone sodium, Gold, Ruthenium, Platinum, Complexes, FTIR, IC50 Bull. Chem. Soc. Ethiop. 2024, 38(4), 937-948. DOI: https://dx.doi.org/10.4314/bcse.v38i4.10

Determination of hardness and Young's modulus in fcc Cu–Ni–Sn–Al alloys via high-throughput experiments, CALPHAD approach and machine learning

Hardness and Young's modulus are critical indicators in the design of innovative Cu–Ni–Sn–Al alloys with desired elastic and strength properties. In this study, the composition-dependent hardness and Young's modulus in the fcc Cu–Ni–Sn–Al alloys were determined using high-throughput experiments, the CALPHAD (CALculation of PHAse Diagrams) approach, and machine learning (ML) model. By combining the diffusion-couples tool, nanoindentation, and electron probe microanalysis (EPMA) techniques, the 341 sets of composition-related hardness and Young's modulus in the fcc Cu–Ni–Sn–Al system, as well as its sub-binary and sub-ternary systems, were effectively determined. These measured data were subsequently utilized to establish the relationship of Young's modulus and hardness with respect to composition in the fcc Cu–Ni–Sn–Al system through the combined application of CALPHAD and back propagation (BP) artificial neural network machine learning models. A comparison between the two approaches revealed that the ML method achieves higher accuracy in ternary and quaternary alloys compared to the CALPHAD method. The impact of alloying elements on the values of hardness and Young's modulus was analyzed, demonstrating that the Ni content has the largest effect on hardness, while the Young's modulus increases with addition of Ni but decreases with the addition of Al and Sn. Finally, the effects of solute elements on the nanomechanical properties of aged Cu1-x(Ni3Sn)x and Cu–9Ni–6Sn-xAl alloys were examined.

Standardization and quantification of backscattered electron imaging in scanning electron microscopy

Backscattered electron (BSE) imaging based on scanning electron microscopy (SEM) has been widely used in scientific and industrial disciplines. However, achieving consistent standards and precise quantification in BSE images has proven to be a long-standing challenge. Previous methods incorporating dedicated calibration processes and Monte Carlo simulations have still posed practical limitations for widespread adoption. Here we introduce a bolometer platform that directly measures the absorbed thermal energy of the sample and demonstrates that it can help to analyze the atomic number (Z) of the investigated samples. The technique, named Atomic Number Electron Microscopy (ZEM), employs the conservation of energy as the foundation of standardization and can serve as a nearly ideal BSE detector. Our approach combines the strengths of both BSE and ZEM detectors, simplifying quantitative analysis for samples of various shapes and sizes. The complementary relation between the ZEM and BSE signals also makes the detection of light elements or compounds more accessible than existing microanalysis techniques.

The impact of environmental humidity on the mechanical property and microstructure of magnesium silicate hydrate cement

Environmental factors have a significant impact on the performance of cement-based materials. As a new type of low-carbon cementitious material, the performance of magnesium silicate hydrate cement (MSHC) under different environmental humidity conditions is crucial for its application. This study aimed to investigate the effects of environmental humidity on the hardening properties of MSHC. Compressive strength tests of MSHC were conducted under four different relative humidity (RH) conditions (RH of 33%, 58%, 75%, and 97%) and water curing (RH-w) condition. Microanalysis techniques were employed to reveal the strength mechanisms of MSHC under different environmental humidity conditions. The results showed that MSHC exhibited the optimal mechanical performance when RH was 75%, reaching 42.29 MPa. When RH was 58%, the compressive strength of MSHC was close to the optimal level, which was 41.02 MPa. However, under other humidity conditions (RH33, RH97, and RH-w), the compressive strength of MSHC was much lower than the optimal level, decreasing by 30.93%, 41.90%, and 63.66%, respectively. Pore structure analysis showed that the volume of detrimental pores (>100 nm) in the sample was the lowest when RH was 75%. Compared with RH75, the volume of detrimental pores in RH33, RH58, RH97, and RH-w increased by 20.47%, 9.83%, 36.77%, and 156.92%, respectively. In addition, the variation of environmental humidity resulted in different polymerization levels in the M-S-H gel, and higher degrees of polymerization were observed when RH was 58% and 75%.

Mitigating the corrosion of AISI 301LN steel in molten carbonate salts by doping with alumina nanoparticles for thermal energy storage applications

Molten carbonate salt nanofluids have become an excellent strategy to enhance the power generation efficiency of the next-generation concentrated solar power (CSP) technology due to their excellent thermophysical properties at high temperatures. The corrosion behaviour in contact with salt nanofluids is one of the main issues to address for implementing cost-effective steels as construction materials for CSP. In the present work, the effects of molten salt nanofluids with Al2O3 nanoparticles (<50 nm and 1.0 wt%) on the corrosion behaviour of AISI 301LN stainless steel have been investigated. Corrosion tests were carried out in a static molten salt mixture of Li2CO3–Na2CO3–K2CO3 at 600 °C for 1000 h. Complementary electron microscopy, microanalysis and optical characterization techniques and micromechanical tests were carried out to study the oxide scales formed after corrosion tests in salt nanofluids and base salt of reference. Results evidenced that doping nanoparticles in molten salts significantly decreased the corrosion rate by ∼50%, compared with a base salt. Incorporating nanoparticles into the oxide scale, forming a nanostructure of reticulated Al2O3 nanoparticles generated a more homogeneous and dense oxide scale, increasing its hardness about 30% and enhancing its effectiveness as a protective barrier.

Microstructural and microchemical analysis of zircon in a syenite lithic fragment from Ulleung Island volcano, South Korea

Abstract Background The intricate textural patterns commonly observed in metamorphosed and recrystallized zircon (ZrSiO4) underscore the crucial necessity of understanding the underlying mechanisms governing their formation to ensure accurate interpretation of the chemical and isotope data they contain. This study employed a combination of microanalytical techniques, including electron backscattered diffraction (EBSD) analysis, electron microprobe (EMP) mapping, and scanning electron microscope (SEM) imaging, to investigate the processes of formation and modification of zircon in a late Pleistocene (~ 35 ka) syenite enclosed within the Nari Tephra Formation on Ulleung Island in South Korea. Findings Under cathodoluminescence (CL), zircons within the syenite reveal dark, featureless, or oscillatory-zoned cores containing numerous inclusions of britholite. These cores are partially or entirely replaced by inward-penetrating bright-CL domains that exhibit minimal inclusion presence. Despite these changes, the external morphologies of the zircons remain largely unchanged, and the faded oscillatory zoning is preserved in the replaced regions. EMP mapping discloses amoebiform micro-domains with high Y, U, and Th concentrations within the dark-CL cores, while the bright-CL domains are relatively deficient in these trace elements. Microstructural analysis of the zircons using EBSD mapping indicates no significant misorientation between the dark-CL cores and the bright-CL rims. Deformation-related low-angle boundaries by lattice distortion are clearly observed in certain grains, cutting across the discrete SEM and EMP domains, and often aligned along submicron pore trails. Conclusions Microstructural and microchemical analyses carried out in this study establish that the zircons within the Ulleung syenite have undergone subsolidus recrystallization, a process likely influenced by the presence of fresh melts or fluids. This recrystallization process could be attributed to either coupled dissolution and reprecipitation or thermoactivated particle and defect volume diffusion due to inherent lattice strain. The subsequent deformation observed in the zircons might be a result of increased stress within the magma system after the recrystallization.

The discovery of synchrony: By means of the projector as a scientific instrument

This article considers the implications for film analysis of the presence or absence of a manual crank. More specifically, it looks at the 16 mm Time and Motion Study Projector as used in behavioral research in the 1960s and 1970s. The controversial concept of ‘interactional synchrony’, or the dance-like coordination of people in conversation, emerged from the use of this hand-turned projector. William S. Condon developed the concept along with the technique of microanalysis. Starting with the projector manufactured by Bell &amp; Howell, he made numerous improvements to facilitate observation—‘sweeping’ over segments of very short duration to discover the rhythmic synchrony of all filmed participants. It led him to a theory of ‘process’ in communication, and in the reception of speech in particular. People always ‘danced’ to the tune of their own voice, and their listeners ‘danced’ to the tune of the speaker—at intervals of one-sixth or one-eighth of a second. This also led Condon to an epistemology of discovery derived partly from philosophy but mostly from his machinery. The universe, he said, is a ‘continuum of order’ whose structures are preserved through translations of order: of thought into speech, speech into vibrations, vibrations into neurons, and back into behavior. The only exceptions are people with disabilities, like the autistics Condon studied from the 1970s onward. But the very distinction of normal and pathological was epiphenomenal to his scanning technique; it was rooted in material and formal qualities of film and of the projector whose crank he turned often.