Stages Of Crystallization Research Articles

Application of in-line Raman spectroscopy to monitor crystallization and melting processes in milk fat

Anhydrous milk fat (AMF) and its fractions are used as ingredients in a wide range of food applications. Obtaining the appropriate solid fat content (SFC) is essential to achieve the desired product texture. At present, in-line monitoring techniques to control milk fat crystallization and melting are largely unavailable. The thermal behaviour of milk fat (AMF and four of its fractions) was monitored in a temperature-controlled vessel using an in-line Raman analyser and compared with thermograms generated using differential scanning calorimetry (DSC). The major stages of milk fat crystallization and melting were identified using the in-line Raman analyser. Thermal data from DSC showed excellent linear correlations with Raman spectral data (R2 value of 0.97 for the onset of milk fat crystallisation). Partial least squares regression (PLSR) models were developed using Raman spectra to predict SFC with coefficient of determination (R2Cs) from 0.929 to 0.992 and root mean standard error of calibration (RMSECs) ranging from 3.20 to 10.36%. Results demonstrated Raman spectroscopy has significant potential as a way of monitoring milk fat crystallization and melting processes.

Petrogenesis of the Dalaku’an Mafic–Ultramafic Intrusion in the East Kunlun, Xinjiang: Constraints from the Mineralogy of Amphiboles

The Dalaku’an mafic–ultramafic intrusion, located in the western segment of the East Kunlun, presents conducive conditions for the magmatic Cu-Ni sulfide deposits. According to the detailed petrographic observation, the amphiboles within distinct rock types were analyzed by EPMA analysis. The crystallization conditions, such as temperature, pressure, oxygen fugacity, and water content of the magma, were calculated to explore the genesis of the intrusion. The amphiboles were divided into three types: Amp-I, characterized by low silicon content but enrichment of aluminum, titanium, and alkali, predominantly comprising Tschermakitic hornblende and Magnesio-hornblende with mantle-derived traits; Amp-II, exhibiting elevated silicon content but diminished levels of aluminum, titanium, and alkali, primarily constituted of Magnesio-hornblende; whereas Amp-III manifests as Actinolitic hornblende, indicative of crustal origins. The calculated temperatures of amphiboles ranged between Amp-I (955–880) °C, Amp-II (852–774) °C, and Amp-III (761–760) °C; the pressures ranged between Amp-I (454–274) MPa, Amp-II (194–93) MPa, and Amp-III (101–84) MPa; the oxygen fugacities (△NNO) ranged between Amp-I (0.93–2.17), Amp-II (1.55–2.52), and Amp-III (1.89); and the water contents (H2Omelt) ranged from (6.69–8.67) to (5.90–7.32). The magma experienced multiple stages of crystallization and underwent complex magma evolution at different depths. The high oxygen fugacity and water content could be attributed to the subduction of the oceanic crust. The magma source of the Dalaku’an intrusion was metasomatized by fluids from subducting plates, thereby originating within a post-collision extension.

Rancangan e-LKPD Berbasis Collaborative Creativity Learning (CCL) Pokok Bahasan Perpindahan Kalor Pada Mesin Pembuatan Gula Pasir

Physics as a subject matter involves understanding concepts and mathematical applications that are often a challenge for students, for example the concept of heat transfer. To provide a memorable and interesting learning experience, the context of the e-LKPD design can be taken from everyday life, such as the process of making granulated sugar in a sugar factory. The process involves the concept of heat transfer, for example the stages of evaporation and crystallisation of neera. The purpose of this study was to analyse the validity of the design and learners' responses to the e-LKPD design. This type of research is development research with the ADDIE model and is limited to the development stage. Data collection involved literature study, observation, interviews, questionnaires, and documentation. The validation results obtained an average percentage value of 87.33%, with a very feasible category and learner responses showed a high level of interest, with a percentage value of 83%. Thus, e-LKPD based on collaborative creativity learning (CCL) on the subject of heat transfer in sugar making machines can be considered feasible and can be implemented effectively to students in learning activities.

Tracking copper nanofiller evolution in polysiloxane during processing into SiOC ceramic.

Polymer-derived ceramics (PDCs) remain at the forefront of research for a variety of applications including ultra-high-temperature ceramics, energy storage and functional coatings. Despite their wide use, questions remain about the complex structural transition from polymer to ceramic and how local structure influences the final microstructure and resulting properties. This is further complicated when nanofillers are introduced to tailor structural and functional properties, as nanoparticle surfaces can interact with the matrix and influence the resulting structure. The inclusion of crystalline nanofiller produces a mixed crystalline-amorphous composite, which poses characterization challenges. With this study, we aim to address these challenges with a local-scale structural study that probes changes in a polysiloxane matrix with incorporated copper nanofiller. Composites were processed at three unique temperatures to capture mixing, pyrolysis and initial crystallization stages for the pre-ceramic polymer. We observed the evolution of the nanofiller with electron microscopy and applied synchrotron X-ray diffraction with differential pair distribution function (d-PDF) analysis to monitor changes in the matrix's local structure and interactions with the nanofiller. The application of the d-PDF to PDC materials is novel and informs future studies to understand interfacial interactions between nanofiller and matrix throughout PDC processing.

On the origin of alkali feldspar megacrysts in granitoids. Part 2: evidence for nucleation and growth under magmatic conditions from crystal size distributions of the Cathedral Peak Granodiorite, California, USA

The mechanisms whereby alkali feldspar megacrysts form have been debated for several decades; yet, we do not understand well the processes that lead to their formation. We take advantage of glacially polished outcrop surfaces from the Cathedral Peak Granodiorite in the Tuolumne Intrusive Complex, CA to quantitatively characterize alkali feldspar textures, to provide better insight into their origin. On the glacially polished surfaces, we traced alkali feldspar crystals > 10 mm in the field. From the same localities, we also collected large slabs and stained them to reveal feldspar textures for crystals < 20 mm in size. We scaned the resulting field tracings and rock slabs to quantify CSDs using image processing techniques with the software ImageJ. The CSDs from glacially polished outcrop surfaces and complementary polished and stained rock slabs reveal two stages of crystallization. Crystals > 20 mm show log-linear CSDs with shallow slopes, suggesting magmatic nucleation and growth on timescales of thousands of years. Crystals < 20 mm define a second stage of crystallization, with much steeper slopes, suggesting a period of enhanced nucleation leading to formation of a groundmass during the final stages of solidification on timescales of decades to centuries. We do not find any evidence for CSDs affected by textural coarsening, or any effects of subsolidus processes. Our data suggest that these megacrysts form in large, slowly cooling magma, where low nucleation rates dominate. These crystals are not special in their magmatic formation—only in their size. A change in solidification conditions led to the formation of a groundmass, which warrants further study to better understand this crystallization stage in a plutonic environment.

On the thermodynamic equilibrium of thermal casting processes

Based on thermodynamic calculations, it is shown that heating and cooling of metals and alloys are reversible, equilibrium processes. Based on thermodynamic calculations, it is shown that melting and crystallization of metals and alloys are also reversible, equilibrium processes. With an increase in the cooling rate of the metal, the temperature of its equilibrium crystallization decreases. At a high rate of metal cooling, a short‑term initial process of nonequilibrium crystallization is observed, which quickly passes into the main stage of equilibrium crystallization.

A study of crystallized behavior, microstructure and magnetic properties of new Co28Fe28Ni19Si13B8Cu1Nb1Mo2 high-entropy metallic glass

The crystallized behavior, microstructure and magnetic properties of Co28Fe28Ni19Si13B8Cu1Nb1Mo2 high-entropy metallic glass are studied by DSC, XRD, TEM and VSM. The results show that two crystallization peaks occur with a difference of approximately 129–149 K, but the activation energy is different. The activation energy of the first peak is 175.3 kJ/mol and the second is that of 460.1 kJ/mol. After annealing, the Co7Fe3 phase first precipitates with a feature of three-dimensional growth. When the annealing temperature is higher than the second crystallization temperature, the phases such as (Fe,Ni,Mo)23B6, Co3Mo2Si, Co4B, Fe3Mo precipitate sequentially, meanwhile Cu accumulates into small clusters to provide heterogeneous nucleation centers for the crystalline phase in the early stage of crystallization. Finally, the Hc increase with temperature, and the Ms first increasing and then decreasing with the maximum value of 93.11 emu/g at 893 K.

Origin and thermal evolution of Cr-V-Ti magnetites (lodestones) from Coorg massif, southern India

This study deals with petrology, textural, thermometry, and geochemical characterization of naturally magnetized Cr-V-Ti magnetite deposits within the layered mafic-ultramafic intrusions in Coorg massif of southern India using ore petrography and mineral/whole rock geochemistry. These deposits, also known as ‘lodestones’, occur as rhythmic layers within the lateritized host rock, with the underlying basement distinguished by the presence of charnockites and layered gabbro-anorthosites and pyroxenites, delineating a stratified intrusive setting. Lodestones exhibit complex mineral assemblage involving magnetite, ilmenite, ulvöspinel, spinel, corundum, hematite, goethite, pyrite, pyrrhotite, and amphiboles. The bulk rock chemistry of the lodestone is analogues to Fe-Ti magnetite iron ore deposits with elevated vanadium and chromium contents. Their resemblance to tholeiitic magma-type suggests their formation in a layered intrusive setting, evolved through multiple fractional crystallization under oxidizing conditions. Thermometric and fugacity calculations using different textural associations estimate the magmatic fractional crystallization stage at elevated temperatures (601–704 °C) and low fO2 (−18.6 to −15.3), succeeded by the exsolution stage during subsolidus cooling at lower temperatures (379–540 °C) and high fO2 (−38.2 to −22.1). The whole sequence of formation and evolution of lodestone encompasses primary magmatic crystallization, subsolidus re-equilibration, metamorphism, and secondary weathering. The study also suggests a genetic linkage of lodestone with the associated mafic-ultramafic units, depicting two possible magmatic processes either through slab melting and fractional crystallization associated with subduction or due to plume magmatism and associated rifting.

Advanced structure research methods of amorphous Co69Fe4Cr4Si12B11 microwires with giant magnetoimpedance effect: Part 3 – Cluster growth and crystal nucleation

This Part 3 focuses on the detailed study of the nanostructures forming in amorphous microwires which were previously received and described in the Part 2. The clustering process was studied at long-term DC Joule heating’s much lower the crystallization temperature. Particular attention is paid to the study of the redistribution of the components of the initial stage of crystallization. The studies were carried out using the Atom Probe Tomography method (APT), which allows for the identification of individually considered atoms. A description and analysis of APT data processing techniques are provided for studying the cluster structure and distribution of elements in the amorphous matrix and crystalline phases. To identify crystalline phases, data obtained using High-Resolution Transmission Electron Microscopy (HR-TEM) and Scanning Transmission Electron Microscopy (STEM), as well as X-Ray Powder Diffraction (XRPD) with synchrotron radiation source were used. The applied techniques made it possible to establish that the formation of nuclei of crystalline phases is preceded by three stages of the amorphous microwire matrix evolution. At the first stage, clusters of the first and second coordination spheres appear. At the second stage, the clusters coagulate and become more than 2 nm in diameter, the stage ends with the predominance of Co-rich and silicide Me-Si clusters. At the third stage, they grow to an average diameter of 4.5 nm, the predominance of clusters of this type remains, and the formation of nuclei of crystalline phases α-Co and Co2Si, with a size of about 8 nm, occurs. This stage is characterized by high stable soft magnetic properties. With a further increase in the heat treatment temperature, a gradual deterioration of the soft magnetic properties and further structural transformation occur – structures of joint crystalline phases from two crystalline phases α-Co and Co2Si are formed in the amorphous matrix, and crystallization occurs with the alternation of these two phases. This leads to a significant redistribution of alloy components. As a result, an amorphous barrier layer is formed in the amorphous matrix near the surface of the growing two-phase substructures, enriched in chromium and silicon; this layer affects the growth of crystalline phases, slowing it down.

PROBABLE APPEARANCE OF THE ANCIENT RUS TRANSFORMATION CHURCH IN THE VILLAGE OF SPAS ACCORDING TO KNOWN ARCHIVE, ICONOGRAPHIC AND HYPOTHETICAL MATERIALS

The currently available materials are outlined and systematized, which can serve as the basis for a proposal to reproduce the original appearance of the now defunct Church of the Transfiguration in the village. Spas in the Sambir region, which are divided into historiographical, hypothetical and reflective. Value levels of the mentioned materials were determined based on the method of mutual agreement. Repetitive data on the architectural features of the building are considered more reliable. Further, this method was developed in the first stage of crystallization of the reproduction concept - a critical analysis of available materials. The next stage was the selection of data for reproduction, which is divided into historiographic, interpolation and architectural data. In particular, the peculiarities of the light context of the creation of the monument are emphasized, which falls on the day of the spread of Eastern Christian mystical practices related to the concept of Hesyham. Therefore, attention was paid to the experience of the contemporaneous sacred construction of the Byzantine area. On the basis of the preparatory works carried out above for the complex scientific analysis of the available materials, a proposal was determined for the reproduction of the appearance of the primary building of the Transfiguration temple in the village. Spas in Sambir region. The following characteristic features have been determined for it: brick masonry with stone inserts and a stone foundation, the presence of a central recess on each of the facades, and the absence of lateral recesses. Double windows in the central spans, four windows in the cupola, etc.

A non-classical crystallization mechanism of microbially-induced disordered dolomite

Non-classical crystallization pathways, involving the formation of complex precursors prior to nucleation, have been observed during the calcification process of invertebrate skeletons and shells. However, these pathways were rarely documented in microbially-induced carbonate precipitation. In this study, we presented experimental evidence demonstrating that a halophilic bacterium (Halomonas sp. strain JBHLT-1) catalyzed the biomineralization of disordered dolomite through an amorphous calcium-magnesium carbonate (ACMC) with a stoichiometry near that of dolomite. During the ACMC formation, strain JBHLT-1 significantly enhanced the incorporation of Mg2+ ions compared to abiotic ACMC that was synthesized without any microbial biomass. In the stage of ACMC crystallization, the presence of microbial biomass reduced the dissolution-reprecipitation rate and induced bias towards a solid-state reaction pathway. This observation was supported by the negligible loss of structural Mg2+ ions in the presence of cells of strain JBHLT-1. The microbially-induced growth of disordered dolomite appeared to follow a spherulitic growth mechanism, as evidenced by its hierarchical structure composed of coalesced nano-spheres, eventually growing into micron-sized spheroids and dumbbells with extended incubation times. Since disordered dolomite is considered as a crucial crystalline precursor of ordered sedimentary dolomite, the findings of this study have important implications for understanding the formation mechanism of natural dolomite.

The Lac à l'Orignal phosphate deposit and constraints on high-quality phosphatic ore in massif-type anorthosite, Grenville Province, Canada

Phosphate is an indispensable component in the fertilizer industry. It has recently become a critical part of the green energy transition because of the demand for lithium ferro phosphate in rechargeable batteries. A significant amount of phosphate ore (∼90 %) is globally produced from sedimentary rocks. High-quality phosphate ore containing low amounts of toxic elements, however, is mostly produced from igneous carbonatite.The Lac à l'Orignal deposit (∼1069–993 Ma), Canada, in the central Grenville Province, contains a large amount of fluorapatite (≤ 20 %) hosted in oxide-bearing norite-gabbronorite-anorthosite layered intrusions. The deposit is hosted in the Vanel Anorthosite (1080 ± 2 Ma) near the northern border of the Mattawa Anorthosite (1016 ± 2 Ma). The major host rock oxide-apatite-gabbronorite (OAGN) is primarily composed of plagioclase, orthopyroxene, clinopyroxene, fluorapatite, ilmenite, and magnetite. The Al contents of the OAGN orthopyroxene indicate that the magmatic deposit was emplaced at mid-low crustal levels (∼2.0–3.6 kbar) and reverse zoning in the OAGN plagioclase suggests <2.5 kbar of pressure change during their crystallization. An overall increase of REE + Y concentrations in the OAGN fluorapatite with decreasing their fluorapatite contents indicates that the magma went through fractional crystallization. This study suggests that high abundances (ca. > 8 %) of fluorapatite in some OAGN were produced from crystal avalanching after initial crystal settling. Antithetic correlation between the Cl content of fluorapatite and the Mg# [Mg/(Mg + Fe2+)] of coexisting orthopyroxene suggests that phosphate ores with low Cl contents are expected for OAGN that formed at the initial stages of magma crystallization. Therefore, the Mg# of the OAGN orthopyroxene provides an exploration tool for targeting phosphate ore with low Cl content, which is preferred in the production of phosphoric acid, a major intermediate feedstock for the fertilizer and green energy industries. Apatite contents in carbonatite and average P2O5 content in carbonatite melt are generally similar to those of the Lac à l'Orignal OAGN. The average concentrations of REE, and toxic metals, such as Pb, Th, and U, in the OAGN fluorapatite are, however, lower than those in apatite from carbonatite worldwide. Therefore, the apatite of the OAGN appears to be of high quality and more environmentally-friendly as a source of phosphate ore.

Studying the features of complex beryllium-containing silicate phases co-crystallization in zonal samples using the x-ray electron probe microanalysis method

Research subject. Silicate ingots containing four species-forming components Be, Mg, Al, and Si and belonging to the crystallization region of beryllium indialite (with the formula of Mg2BeAl2Si6O18 and a beryl-type structure). Aim. To investigate the fundamental problem of identifying the patterns of matter differentiation and the stable and metastable phase formation in silicate matrices. Methods. The evolution of the phase composition of silicate melts was registered using a temperature gradient method. Results. New data on the features of phase transformations in silicate melts belonging to the region of beryllium indialite were obtained by electron probe microanalysis (EPMA). Co-existing metastable and stable mineral phases were identified, and the similarity of their compositions with different structures was shown. The nature of impurity phases at each stage of crystallization was established. Conclusions. The evolutionary sequence of phase associations ensuring the crystallization of beryllium indialite and metastable phases of a similar composition, the nature of which is determined by the initial ratio of components, was experimentally recorded. The range of possible phase associations that co-crystallize or replace a stable phase with a beryl structure in melts from the region of existence of beryllium indialite in the BeO–MgO–Al2O3–SiO2 system was extended. The selectivity of the coloring element chromium entry into various phases of the studied system is shown depending on the capabilities of their structure. The addition of a chromophore is a reliable criterion for visualizing successive layers, zones, and areas of changing phase associations in the final ingot.

A Late Jurassic Epithermal Pb-Zn Deposit: Insights from Rb-Sr Dating of Quartz-Hosted Fluid Inclusions and Sphalerite Chemical Composition

The Kangjiawan Pb-Zn deposit, situated within the Shuikoushan polymetallic ore field in Changning, Hunan Province, China, is a large-scale Pb-Zn deposit unearthed in 1976. Based on detailed geological field investigations, this study presents the results of the Rb-Sr isotopic dating, electron probe microanalyses (EPMAs), and LA-ICP-MS analyses of the Kangjiawan Pb-Zn deposit in order to determine the ore-forming age and the occurrence of trace elements in sphalerite and thereby constrain the genesis of the deposit. The Rb-Sr dating of quartz-hosted fluid inclusions yielded an Rb-Sr isochron age of 150 ± 4 Ma, with an initial 87Sr/86Sr ratio of 0.71101 ± 0.00008 (MSWD = 1.1), suggesting that the Pb-Zn mineralization of the Kangjiawan deposit took place during the Late Jurassic, coeval with the magmatic activities within the ore field. EPMA and LA-ICP-MS analyses showed that Fe, Mn, and Cd were primarily incorporated into the sphalerite lattice through isomorphous substitution. Specifically, Fe and Mn substituted for Zn, whereas Cd replaced both Fe and Zn. Other elements such as Cu, Sb, and Sn occurred within the sphalerite lattice through mineral micro-inclusions or isomorphic substitution. EPMAs and LA-ICP-MS results showed that the FeS contents in sphalerite were less than 14.33%, with corresponding ore-forming temperatures below 259 °C. The LA-ICP-MS results showed that sphalerites from the Kangjiawan Pb-Zn deposit had relatively high Ga/In ratios ranging from 0.01 to 144, providing further support for medium-to-low-temperature mineralization. The trace element compositions of sphalerites from the Kangjiawan Pb-Zn deposit exhibit skarn-type characteristics, suggesting a potential association with contemporary magmatic activities within the Shuikoushan ore field. During the Late Jurassic, extensive granitic magmatic activities occurred in the study area. At the late stage of magma crystallization, hydrothermal fluid containing Pb and Zn precipitated at medium-to-low temperatures and generated the Kangjiawan Pb-Zn deposit.

Syntectonic Shear-induced Emplacement of Crystallizing Granite Magmas Evident from Magmatic Shear Sense, Mafic Schlierens, and Microgranular Enclaves in the Mesoproterozoic A-type Kanigiri Pluton, Nellore Schist Belt, Southeast India

ABSTRACT The observations on field-based mesoscale magmatic structures suggest that the A-type Kanigiri granite (KG) pluton, Nellore Schist Belt (NSB) has undergone a long plutonic history as evidenced by the continuum of deformation from early magmatic to the ductile regime at the waning stage of pluton evolution. The linear alignment of the KG pluton, which lies sub-parallel to the regional Terrane Boundary Shear Zone (TBSZ), and the long-standing deformation regime indicate the genetic link with this shear zone. The formation of mafic schlierens in the KG pluton owes to the mechanical crystal flow-sorting process during the replenishment of KG magma, which is further induced by the injection of crystal-charged microgranular enclave (ME) magmas in the crystallizing felsic magma chamber. The outflown ME magma blobs from the walls of the conduit during the invasion trigger the local turbulence, resulting the swirling of early crystallized mafic crystals of the host KG magma. This kind of swirling in the host KG magma must have been formed at an early stage of crystallization i.e., crystal-poor condition of the KG melts. When the MEs flow out, gravity causes them to interact with the host KG magma and attempt to dissolve into it. This results in schlieren rims formed around the MEs. The magmatic shearing observed in the KG pluton results from an active crystal-mush environment due to accumulated strain caused by the syntectonic movement as evidenced by the magmatic sense of shears. The locally formed slickensides are sub-magmatic origin during the upward pushing of replenishing ME and another pulse of KG magma. The presence, spread and prevalence of magmatic structures like ME magma globules, magma flowage, mafic schlierens, slickensides and shear sense indicators in the KG pluton suggest that the KG pluton underwent dynamic magma emplacement and evolution due to a shear zone, probably the TBSZ, which acted upon KG pluton in a syntectonic environment.

Effectiveness study of recrystallisation method in pharmaceutical salt production from processed salt with zero waste concept

Indonesia's vast archipelago offers abundant seawater resources, holding the potential for salt production. Salt, a vital commodity in human life, typically contains sodium chloride and impurities like Ca2+, Mg2+, SO42−, and K+. Pharmaceutical salt is an industrial category adhering to pharmacopoeial standards regarding sodium chloride levels and impurity content, ensuring quality for drug preparations in Indonesia. Prior research indicates that recrystallisation, specifically evaporation crystallisation, enhances salt quality by increasing NaCl content. Chemical precipitating agents like NaOH and Na2CO3 can be introduced to improve salt purity further. This study aims to identify optimal conditions for pharmaceutical salt production from processed salt raw materials, considering crystallisation time, stirring speed, chemical additives (NaOH and Na2CO3), and double crystallisation stages. The method commences with pre-treatment, involving salt dissolution in distilled water to saturation, with the addition of precipitating agents as per designated variables. Precipitates formed from precipitating agents (NaOH and Na2CO3) are isolated through filtration. The filtrate undergoes evaporation crystallisation at 103 °C, varying between single and double crystallisation. Salt crystals are separated, dried, and weighed to calculate yield. Pharmaceutical salt is analysed for water content, NaCl, and impurities (Ca2+, Mg2+, SO42−, and K+). The optimal conditions for pharmaceutical salt production were double crystallisation with a 20 % excess of chemicals (NaOH and Na2CO3), 100 min of crystallisation time, and a stirring speed of 600 rpm. This yielded a 15 % NaCl content of 99.87 %, Mg2+ at 0 ppm, Ca2+ at 69.6 ppm, SO42− at 366 ppm, K+ at 370 ppm, and water content at 0.166 %. Notably, the pharmaceutical salt production process generates no waste, as byproducts like Mg(OH)2 and CaCO3 can be recycled and hold commercial value. However, it is essential to re-evaluate raw materials and technologies to address the market's high cost and competitiveness issues.

Automatic Control of Nucleation and Crystal Growth Using Online Raman Analyzer

The accurate determination of crystal formation during crystallization is crucial for obtaining crystal products with consistent quality and quantity. In this study, we aimed to identify the feasibility of using Raman spectroscopy to monitor the crystal growth stage in the crystallization process using cephalosporin intermediate 7-ACT as an example molecule. By observing the changes in the characteristic peak of the 7-ACT crystal (504 cm−1) and the characteristic peak of the solvent acetonitrile (914 cm−1), a correlation between the crystal growth stage and the change in the Raman intensity of the crystal solution was discovered. The determination of the optimal starting time for the crystal growth stage through a Raman analyzer significantly improves the consistency of crystal product quality. This led to a fivefold reduction in the variation in the weight and water content of the final 7-ACT crystal products compared to those obtained via manual control. In addition, our experiments also indicated that Raman monitoring could be more efficient at enabling the chemical synthesis reaction to be completed compared to manual control. Thus, our work demonstrates the potential of Raman spectroscopy in the real-time control of chemical synthesis reactions and crystallization processes.

Studying crystallisation processes using electron microscopy: The importance of sample preparation.

We present a comparison of common electron microscopy sample preparation methods for studying crystallisation processes from solution using both scanning and transmission electron microscopy (SEM and TEM). We focus on two widely studied inorganic systems: calcium sulphate, gypsum (CaSO4·2H2O) and calcium carbonate (CaCO3). We find significant differences in crystallisation kinetics and polymorph selection between the different sample preparation methods, which indicate that drying and chemical quenching can induce severe artefacts that are capable of masking the true native state of the crystallising solution. Overall, these results highlight the importance of cryogenic (cryo)-quenching crystallising solutions and the use of full cryo-TEM as the most reliable method for studying the early stages of crystallisation.

Lithium systematics in the Krafla volcanic system: comparison between surface rhyolites and felsic cuttings from the Iceland deep drilling project -1 (IDDP-1)

The unexpected discovery of felsic magma by the Iceland Deep Drilling Project-1 (IDDP-1) in the Krafla volcanic system (KVS) presents a unique opportunity to investigate pre-eruptive lithium (Li) dynamics and establish a more direct connection between magma reservoirs and volcanic deposits. Our study provides new insights into Li abundances and isotope compositions in bulk-rock, minerals, and groundmass glass from rhyolitic lavas at KVS, encompassing various stages of groundmass crystallisation. Additionally, we examined felsic cuttings retrieved from the IDDP-1 well, comprising crystal-poor obsidian and crystal-bearing to -rich ‘felsite’ particles. Groundmass glasses from surface lavas show limited variability in K/Na, indicating limited secondary hydration of the glasses and that their Li contents seem to not be affected by this post-eruptive process. Lithium inventories in groundmass glasses and minerals within lavas exhibit variations consistent with the cooling history of the deposit, resembling patterns seen in Snake River Plain ignimbrites. Lithium contents of glassy rhyolitic lavas, whether bulk-rock (avg. 27.2 ± 3.1 μg/g) or groundmass glass (average 28.4 ± 4.7 μg/g), and their bulk isotopic compositions (avg. δ7Li =+ 4.4 ± 0.2‰) overlap with those observed in IDDP-1 obsidian cuts (avg. 24.9 μg/g Li in bulk, 28.6 ± 1.5 μg/g in groundmass glass, and δ7Li = 4.5 ± 0.2‰). Glassy lavas lacking spherulites may potentially preserve pristine magmatic Li element and isotope compositions, while areas with extensive groundmass crystallisation reveal Li enrichments in phenocrysts. Plagioclases in slowly cooled parts of the deposit record a two-fold increase in Li contents compared to plagioclase found in glassy counterparts, along with evidence of open-system degassing marked by heavier bulk Li isotope compositions and lower bulk Li contents of the crystallised lava portions (avg. δ7Li = +7.2 ± 0.1‰ and 7 ± 0.8 μg/g Li) relative to bulk glassy lithologies (avg. δ7Li = +4.1 ± 0.1‰ and 28 ± 2 μg/g Li). Partition coefficients derived from IDDP-1 cuts successfully predict Li inventories in vitrophyres of rhyolites on the surface of the KVS. Lithium isotope compositions of the crystal-rich IDDP-1 cuts are significantly heavier (avg. δ7Li = +7.2 ± 0.2‰) than lavas and IDDP-1 obsidian cuts, casting doubt on the notion that the IDDP-1 rhyolitic magma could result from the melting of felsite lenses in the KVS. Lithium contents in groundmass glasses within IDDP-1 crystal-rich cuts show higher Li contents (avg. 55.1–60.7 μg/g), correlating with the higher crystal content and an increase in other incompatible elements (avg. 250 μg/g Rb) relative to obsidian cuttings (avg. 75 μg/g Rb).

Emplacement of shergottites in the Martian crust inferred from three‐dimensional petrofabric and crystal size distribution analyses

AbstractShergottites are mafic to ultramafic igneous rocks that represent the majority of known Martian meteorites. They are subdivided into gabbroic, poikilitic, basaltic, and olivine–phyric categories based on differences in mineralogy and textures. Their geologic contexts are unknown, so analyses of crystal sizes and preferred orientations have commonly been used to infer where shergottites solidified. Such environments range from subsurface cumulates to shallow intrusives to extrusive lava flows, which all have contrasting implications for interactions with crustal material, cooling histories, and potential in situ exposure at the surface. In this study, we present a novel three‐dimensional (3‐D) approach to better understand the solidification environments of these samples and improve our knowledge of shergottites' geologic contexts. Shape preferred orientations of most phases and crystal size distributions of late‐forming minerals were measured in 3‐D using X‐ray computed tomography (CT) on eight shergottites representing the gabbroic, poikilitic, basaltic, and olivine–phyric categories. Our analyses show that highly anisotropic, rod‐like pyroxene crystals are strongly foliated in the gabbroic samples but have a weaker foliation and a mild lineation in the basaltic sample, indicating a directional flow component in the latter. Star volume distribution analyses revealed that most phases (maskelynite, pyroxene, olivine, and oxides/sulfides) preserve a foliated texture with variable strengths, and that the phases within individual samples are strongly to moderately aligned with respect to one another. In combination with relative cooling rates during the final stages of crystallization determined from interstitial oxide/sulfide crystal size distribution analyses, these results indicate that the olivine–phyric samples were emplaced as shallow intrusives (e.g., dikes/sills) and that the gabbroic, poikilitic, and basaltic samples were emplaced in deeper subsurface environments.