Natural Crystallization Research Articles

Insights on Arc Magmatic Systems Drawn from Natural Melt Inclusions and Crystallization Experiments at PH2O =800 MPa under Oxidizing Conditions

Abstract Whole rock compositions at Buldir Volcano, western Aleutian arc, record a strong, continuous trend of iron depletion with decreasing MgO, classically interpreted as a calc-alkaline liquid line of descent. In contrast, olivine-hosted melt inclusions have higher total iron (FeO*) than whole rocks and show little change in FeO* with decreasing MgO. To investigate this discrepancy and determine the conditions required for strong iron depletion, we conducted oxygen fugacity (ƒO2) buffered, water-saturated crystallization experiments at 800 MPa and ƒO2 = QFM+1.6 ± 0.4 (1$\sigma$) (where QFM refers to the quartz-fayalite-magnetite buffer) on a high-Al, basaltic starting material modeled after a Buldir lava. Experimental conditions were informed by olivine-hosted melt inclusions that record minimum entrapment pressures as high as 570 MPa, >6 wt.% H2O, and ƒO2 of QFM+1.4 (±0.2), making Buldir one of the most oxidized and wettest arc volcanoes documented globally. The experiments produce melts with Si-enrichment and Fe-depletion signatures characteristic of evolved, calc-alkaline magmas at the lowest MgO, although FeO* remains roughly constant over most of the experimental temperature range. Experiments saturate CrAl-spinel and olivine at 1160oC, followed by clinopyroxene and Al-spinel at 1085oC, hornblende at 1060oC, and, finally, plagioclase and magnetite between 1040oC and 960oC. Hornblende crystallization, not magnetite, generates the largest increase in SiO2 and largest decrease in FeO* in coexisting melts. Compositions of melt inclusions are consistent with experimental melts and reflect crystallization of a basaltic parent magma at high PH2O. In contrast, the whole rock compositional trends are influenced by magma mixing and phenocryst redistribution and accumulation. The crystallization experiments and natural liquids (melt inclusions and groundmass glass) from Buldir suggest that for an oxidized, hydrous primary basalt starting composition, significant Fe-depletion from the melt will not occur until intermediate to late stages of magma crystallization (< ~4.5 wt.% MgO). We conclude that the Buldir whole rock trend cannot be reproduced by crystallization at arc-relevant oxygen fugacities and is not a true liquid line of descent, warranting caution when interpreting volcanic trends globally.

Transition state of matter in the fluctuation model of crystal growth

Two mechanisms of the effect of the transition state of building particles (activated complexes according to S. Arrhenius) on the crystal growth rate within the framework of the fluctuation model of dislocation crystal growth are discussed. Transition state clusters adsorbed on the surface of the growing face perform the function of an impurity that lowers the surface energy of the crystal at the time moments between free energy fluctuations. Thus, the transition state of the crystallizing substance by the first mechanism affects the relaxation rate of the secondary adsorption of impurities and shortens the time period of attachment of building particles to the crystal face. Other clusters formed in solution reduce the number of free particles and under conditions of low concentration of the building substance are able to decrease the crystallization rate. Nevertheless, in a natural multicomponent crystallization environment, at low concentrations of building material, significant thermal effect of crystallization and small deviations from equilibrium, the role of the transition state in crystal growth is generally insignificant.

Hydrophilicity regulation and microstructure change of Ethylene-tetrafluoroethylene copolymer films grafted acrylic acid by irradiation-induced co-grafting

The surface hydrophobicity of Ethylene-tetrafluoroethylene copolymer(ETFE) films limits its application in functional membranes. However, the surface energy of ETFE films is extremely low and the interface compatibility is poor, which makes it difficult to modify the surface hydrophilicity. In this work, acrylic acid was grafted onto ETFE films by the irradiation-induced co-grafting method. The effects of adsorbed dose on the structure and properties of grafted ETFE films were investigated by the various characterization methods. By irradiation- induced grafting method, the surface of ETFE films were successfully grafted with acrylic acid to modify its hydrophilicity. With the increase of absorbed dose, the contact angle of the ETFE was reduced from 102° to 44°, the microstructure and the natural crystallization area was destroyed, and the radius of gyration decreased. The destruction of the structure leads to a decrease in mechanical properties. When the absorbed dose is 60 kGy, it exhibits good hydrophilicity and mechanical properties. The contact angle, breaking strength and elongation at break are 68°, 13.0 MPa and 72.6 %, respectively. It clarified the effect of adsorbed dose on the structure of ETFE grafted acrylic acid, and helped to expand the application of ETFE in battery separators and other fields.

Tailoring Crystallization Dynamics of CsPbI3 for Scalable Production of Efficient Inorganic Perovskite Solar Cells

AbstractAll‐inorganic perovskite cesium lead triiodide (CsPbI3) with inorganic nature, low‐temperature synthesis, and a suitable bandgap is desirable for high‐performance photovoltaics. However, the scalable production of CsPbI3 photovoltaics is still challenging due to a large nucleation energy barrier and slow phase transition during unassisted natural crystallization. Here, the crystallization dynamics of CsPbI3 thin films is tailored via lead acetate (PbAc2) substitution in the perovskite precursor ink, allowing the scalable fabrication of efficient all‐inorganic perovskite solar cells and minimodules. Introducing PbAc2 enlarges CsPbI3 colloid size in the precursor and reduces the nucleation energy barrier. Additionally, reactions between acetate and dimethylammonium in the wet film accelerate the removal of dimethylammonium additives and generate solvent vapors for self‐regulate internal solvent annealing, resulting in densely packed, uniform, and pinhole‐free CsPbI3 perovskite films over large areas. This strategy demonstrates inverted CsPbI3 solar cells with 20.17% efficiency and good operational stability (retaining 95.5% of initial efficiency after continuous operation for 1800 h) and 15.1%‐efficient CsPbI3 minimodules with an active area of 26.8 cm2.

Effect of ethyl acetate on crystal quality of HMX in the acetone

Crystal quality of explosive affects its processability and safety. The addition of ethyl acetate can effectively improve the surface of HMX crystal in refining process of HMX. The natural volatilization crystallization method was used to study the effect of ethyl acetate content of 0%, 1%, 1.46%, 2.9%, 4.33% and 5% on HMX crystal morphology, crystal form, thermal decomposition properties and crystal quality in acetone-ethyl acetate system. Addition of ethyl acetate less than 4.33%, no change on the morphology and crystal form of HMX, but promotes the β-to δ- polymorphic transition during the decomposition of HMX crystals, and the HMX crystal quality deteriorates. In the research range, when the addition amount reaches 5%, the crystal quality is improved.

Structural and component characterization of the B4C neutron conversion layer deposited by magnetron sputtering

Neutron conversion detectors that use 10B-enriched boron carbide are feasible alternatives to 3He-based detectors. We prepared boron carbide films at micron-scale thickness using direct-current magnetron sputtering. The structural characteristics of natural B4C films, including density, roughness, crystallization, and purity, were analyzed using grazing incidence X-ray reflectivity, X-ray diffraction, X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry, and scanning electron microscopy. A beam profile test was conducted to verify the practicality of the 10B-enriched B4C neutron conversion layer. A clear profile indicated the high quality of the neutron conversion of the boron carbide layer.

Trace Water Effects on Crystalline 1-Ethyl-3-methylimidazolium Acetate.

Spontaneous room-temperature crystallization of 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]) was observed upon removal of trace water. Sample purity was confirmed using analytical nuclear magnetic resonance spectroscopy to ensure that trace water or other contaminants did not produce this observation. Raman spectroscopy and simultaneous quartz crystal microbalance/infrared spectroscopy measurements were used to study molecular reorganization during crystallization and decrystallization using trace water in the form of atmospheric moisture. These experimental results were supplemented with density functional theory calculations that indicate imidazolium cation ring stacking and side chain clustering with an exclusive arrangement of the acetate anion in the cation ring plane upon water removal. Crystal structure formation was confirmed using two-dimensional wide-angle X-ray scattering. This natural crystallization is attributed to the removal of trace water over extended periods of time and calls attention to the molecular-level role of water in the structure of hygroscopic ionic liquid systems.

Tautomerism unveils a self-inhibition mechanism of crystallization

Modifiers are commonly used in natural, biological, and synthetic crystallization to tailor the growth of diverse materials. Here, we identify tautomers as a new class of modifiers where the dynamic interconversion between solute and its corresponding tautomer(s) produces native crystal growth inhibitors. The macroscopic and microscopic effects imposed by inhibitor-crystal interactions reveal dual mechanisms of inhibition where tautomer occlusion within crystals that leads to natural bending, tunes elastic modulus, and selectively alters the rate of crystal dissolution. Our study focuses on ammonium urate crystallization and shows that the keto-enol form of urate, which exists as a minor tautomer, is a potent inhibitor that nearly suppresses crystal growth at select solution alkalinity and supersaturation. The generalizability of this phenomenon is demonstrated for two additional tautomers with relevance to biological systems and pharmaceuticals. These findings offer potential routes in crystal engineering to strategically control the mechanical or physicochemical properties of tautomeric materials.

Natural crystallization properties of honey and seed crystals-induced crystallization process for honey performance enhancing

Honey crystallization is a common occurrence, while the underlying mechanisms are not clear. Here we evaluated natural crystallization and induced crystallization of honey. By using the method of microscopy, colorimetry, rheology, texture, and calorimetry to investigate the main physical and structural properties and compare with honey seed crystals-induced crystallization in six unifloral honey. The results showed honey transformed into a pseudoplastic fluid during natural crystallization, with the increase of L-value, firmness and cohesiveness and the fastest crystallization rate occurring at 14 °C and water content of 16%. The effect of the addition of seed crystals in the honey crystallization can be summarized as the acceleration of crystallization rate (3 times) and the improvement of crystallization characteristics including uniform particles and reducing stratification. This study provides insight into honey crystallization theory and a resource for the further exploration and development of the new performance of honey products.

The Ambiguous Functions of the Precursors That Enable Nonclassical Modes of Olanzapine Nucleation and Growth

One of the most consequential assumptions of the classical theories of crystal nucleation and growth is the Szilard postulate, which states that molecules from a supersaturated phase join a nucleus or a growing crystal individually. In the last 20 years, observations in complex biological, geological, and engineered environments have brought to light violations of the Szilard rule, whereby molecules assemble into ordered or disordered precursors that then host and promote nucleation or contribute to fast crystal growth. Nonclassical crystallization has risen to a default mode presumed to operate in the majority of the inspected crystallizing systems. In some cases, the existence of precursors in the growth media is admitted as proof for their role in nucleation and growth. With the example of olanzapine, a marketed drug for schizophrenia and bipolar disorder, we demonstrate that molecular assemblies in the solution selectively participate in crystal nucleation and growth. In aqueous and organic solutions, olanzapine assembles into both mesoscopic solute-rich clusters and dimers. The clusters facilitate nucleation of crystals and crystal form transformations. During growth, however, the clusters land on the crystal surface and transform into defects, but do not support step growth. The dimers are present at low concentrations in the supersaturated solution, yet the crystals grow by the association of dimers, and not of the majority monomers. The observations with olanzapine emphasize that detailed studies of the crystal and solution structures and the dynamics of molecular association may empower classical and nonclassical models that advance the understanding of natural crystallization, and support the design and manufacture of promising functional materials.

Selective Production of Xylooligosaccharides by Xylan Hydrolysis Using a Novel Recyclable and Separable Furoic Acid.

Xylooligosaccharides (XOS) have gained considerable attention worldwide as prebiotics due to their immune-strengthening activity and beneficial gut bacteria development and can be produced from xylan-rich resources by acid hydrolysis. The present study proved the organic acid hydrolysis to be beneficial for XOS yield. In this study, a recyclable and separable organic acid, i.e., furoic acid, was used for hydrolyzing xylan to produce XOS, and the response surface methodology design was applied to maximize the XOS yield; the results indicated that the quadratic model terms of the interaction between reaction temperature and hydrolysis time showed the most significant impact on XOS yields (P < 0.05). The predicted maximum yield of XOS was 49.0% with 1.2% furoic acid at 167°C for 33 min, being close to the experimental value (49.2%), indicating that the fitted models were in good agreement with the experimental results. Meanwhile, the primary byproducts, including xylose and furfural, were concurrently bio-oxidized into xylonic acid and furoic acid by Gluconobacter oxydans and separated by electrodialysis. Subsequently, the furoic acid with low solubility (<3.7%, 25°C) was recovered by natural crystallization. The above results indicate that the use of multi-steps contributes to sustainable XOS production by furoic acid.

Molecular dynamics study of the effect of extended ingrain defects on grain growth kinetics in nanocrystalline copper

The paper presents results of a large-scale classical molecular dynamics study into the effect of ingrain defects on the grain growth rate of face centered cubic nanocrystalline material under thermal annealing. To do this, two types of virtual MD samples are used. The samples of the first type are constructed artificially by filling Voronoi cells with atoms arranged in fcc lattice essentially with no ingrain defects. The other samples are obtained by natural crystallization from melted material and contain numerous extended ingrain defects. These samples with a high concentration of ingrain defects imitate nanocrystalline material produced by severe plastic deformation via high pressure torsion or equal channel angular extrusion. The samples of both types are subjected to long-time zero pressure isothermal annealing at Tapprox 0.9T_m (T_m is melting temperature) which leads to grain coarsening due to recrystallization. Direct molecular dynamics simulations of the annealing of different samples show that at the same conditions recrystallization goes two times faster in the samples with a high concentration of extended ingrain defects than in the defect-free samples. That is, to increase the thermal stability of nanostructured material the technologies used for forming nanocrystalline structures should be developed so as to avoid the thermomechanical treatment regimes leading to the formation of structures with high concentration of ingrain defects.

Study on components and structure of difference Vietnamese starch sources

In this study, we focused was on the determination of amylose and amylopectin components of starch from different plant sources in Vietnam by UV-VIS spectroscopy. Besides, the distribution of natural starch structure and crystallization level of different starches was also evaluated by FT-IR, XRD analysis methods. By UV-VIS absorption spectroscopy, we could quantify amylose and amylopectin contents which are the two main components in different starch sources in Vietnam. Our results have showed that corn starch sample had the highest amylose content at 28.22%wt. The degree of morphology in the structure is evaluated through FT-IR spectroscopy method and the crystallization ability of starch was determined by XRD diffraction method. These results showed that although the amylose content of arrowroot starch sample (27.24%) is higher than that of cassava starch (10.31%) or rice starch samples (17.10%), but the tightness rearrange level in the structure of dong starch is the smallest (0.2089) compared to cassava starch (0.2793) or rice starch (0.6645). After all these effective results, starch sample having the good properties and degree of crystallization as well as suitable amylose pectine content will be selected to for further plasticization and modification for the application in elaboration of biodegradable starch based composite materials.

Purification efficiency of natural freeze crystallization for urban wastewaters

Human population growth and urbanization are aggravating water quality problems in many regions, and wastewater volumes and quantities of pollutants are increasing due to greater industrial and urban activity. Thus, it is necessary to find efficient, sustainable and simple methods to separate miscellaneous impurities from wastewaters. One potential separation methods is freeze crystallization, because of its non-selective nature. However, previous research investigating freeze separation using real wastewaters has been rather marginal.This study examines natural freeze crystallization in purification of urban origin wastewaters, that is, municipal wastewater and landfill leachate of various organic and inorganic matter concentration. The effect of different freezing conditions on ice growth and separation efficiency in terms of ice impurity relative to initial solution impurity was investigated with a laboratory scale winter simulator. The results showed air flow velocity to have an almost as significant an influence on ice mass growth as air temperature. Although separation efficiencies decreased linearly with increased ice growth rates, no clear correlation was found between the impurity concentration of the wastewater and the ice mass growth rate. This finding notwithstanding, the separation efficiency of freeze crystallization of concentrated wastewater (landfill leachate) was noted to decrease more clearly with increased ice growth rate. Purification efficiencies of 95% to nearly 100%, determined by indicators such as chemical oxygen demand (COD), were achieved in treatment of municipal wastewater when using low ice growth rates. These findings indicate that the approach can meet future legislative requirements for treatment plants and that further research of the utilization of freezing techniques for wastewater purification is warranted.

Purity and mechanical strength of naturally frozen ice in wastewater basins

A fairly clean ice cover can form over a contaminated water pond when the air-cooled surface of water freezes and impurities are efficiently expelled to the remaining water underneath. Natural freeze crystallization has recently been studied as a potential wastewater purification method with aqueous solutions on a laboratory scale. The effect of impurity inclusions on ice strength has been researched in model ice basins over the past few decades. It is of interest to discover how efficiently natural freeze separation works under real weather conditions before freezing can be utilized for wastewater treatment application. Herein, understanding the mechanical strength properties of naturally frozen wastewater (ice) is important when planning ice breaking and harvesting devices.This research implemented in-situ measurements of the flexural and compressive strength of ice in natural ice-covered environments of a freshwater lake, two peatlands and three mining site basins, and compares the determined strength with analyzed impurities of the ice. The results showed that despite varying ice growth conditions and initial water constituents, it was possible to deduce an evident yet simple relationship between mean ice strength and ice impurities: the more impure the ice is, the lower the value of strength is Based on this exploration, it was concluded that separation efficiencies, i.e. the impurity removal ratio between basin water and ice, from 65% up to 90% can be achieved by natural freezing.

Direct-write of free-form building blocks for artificial magnetic 3D lattices

By the fabrication of periodically arranged nanomagnetic systems it is possible to engineer novel physical properties by realizing artificial lattice geometries that are not accessible via natural crystallization or chemical synthesis. This has been accomplished with great success in two dimensions in the fields of artificial spin ice and magnetic logic devices, to name just two. Although first proposals have been made to advance into three dimensions (3D), established nanofabrication pathways based on electron beam lithography have not been adapted to obtain free-form 3D nanostructures. Here we demonstrate the direct-write fabrication of freestanding ferromagnetic 3D nano-architectures. By employing micro-Hall sensing, we have determined the magnetic stray field generated by our free-form structures in an externally applied magnetic field and we have performed micromagnetic and macro-spin simulations to deduce the spatial magnetization profiles in the structures and analyze their switching behavior. Furthermore we show that the magnetic 3D elements can be combined with other 3D elements of different chemical composition and intrinsic material properties.

Process for the successive production of calcium galactonate crystals by Gluconobacter oxydans

Galactonic acid and its salts can be potentially used in foodstuffs and as specialty chemicals. So far, the researches on microbial conversion of galactose to galactonate are still scarce. In this study, we initially used Gluconobacter oxydans strain NL 71 to convert galactose to galactonic acid via aerobic fermentation by fed-batch and product separation process in shaken flasks, finally 390 g/L galactonic acid could be obtained after 96 h fermentation. To harvest calcium galactonate product, an aeration-agitation bioreactor with product drain port was applied. The lower solubility of calcium galactonate aided its crystallization during fermentation and after 96 h fermentation, approximately 720 g calcium galactonate crystals were produced from 1 L broth. The results showed that successive production of calcium galactonate by a combination of fed-batch and natural crystallization in the process of fermentation was feasible.

Pediatric renal stone disease

Pediatric renal stone disease is manifested as nephro/urolithiasis (UL) and/or nephrocalcinosis (NC). Compared to adults, UL in childhood is less common, and it is believed to be around 5% in industrialized countries, while the incidence of NC is even lower except for critically ill premature infants in whom it may reach 64%. The formation of UL and NC is caused by increased concentration of relevant solutes, and their aggregations and adherence to the renal tubules cell is facilitated by factors such as urine pH, inability of natural crystallization inhibitors, stasis of urine as well as renal tubule damage. UL is associated with significant morbidity because of pains, susceptibility to urinary tract obstruction and infections, and the necessity of surgical procedures. NC is usually asymptomatic but is frequently progressive, and more often than UL, leads to chronic renal failure. Although other imaging modalities can be used in the diagnosis of renal stone disease, ultrasound has the least risk and is most cost-effective. The majority cases of UL and NC in children are of metabolic origin and thus they are prone to recurrence and may cause chronic renal damage. Therefore, they deserve, even after their initial presentation a detailed metabolic evaluation. Genetic source of renal stone disease is suspected in the following conditions: early onset, familial prevalence, familial consanguinity, multiple or recurrent stones, and NC. For all UL/NC etiologies early identification and personalized treatment of the basic disorder is the most important.

Cubic Phase Light Emitters Hetero-integrated on Silicon.

GaN emitters have historically been of hexagonal phase due to natural crystallization. Here we introduce a cubic phase GaN emitter technology that is polarization-free via cointegration on cheap and scalable CMOS-compatible Si(100) substrate.

Effect of Ionic Liquids on the Separation of Sucrose Crystals from a Natural Product Using Crystallization Techniques

The present work aims to investigate the applicability of ionic liquids (ILs) for natural ingredient crystallization. First, the medicinal plant, namely Angelica gigas Nakai, was extracted using methanol (MeOH) as a solvent. Afterwards, ILs 1-butyl-3-methylimidazolium tetrafluoroborate (BMImBF4), 1-butyl-3-methylimidazolium hexafluorophosphate (BMImPF6), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMImTFSI), 1-allyl-3-ethylim idazolium tetrafluoroborate (AEImBF4), and 1,3-diallyl imidazolium tetrafluoroborate (AAImBF4), in three ratios of 1:1, 1:2, and 1:3 (extraction solution/ILs (v/v)) were used as an anti-solvent to induce crystallization. Crystals were obtained within 8 h and were then identified to be pure crystals of sucrose through nuclear magnetic resonance (1H-NMR) analysis. Moreover, the single-crystal X-ray diffraction (SXD) analysis revealed all recovered crystals have an identical crystal structure and the morphology was monitored using a video microscope. With the application of BMImBF4 and BMImPF6, transformation of sucrose crystal morphology from an elongated hexagon shape to an elongated rectangular shape was observed with respect to the respective concentration increase. Here, all crystals precipitated from BMImBF4 and BMImPF6 were found to possess identical PXRD patterns. However, when BMImTFSI was employed, small rectangular crystals attached to the larger rectangular-shaped crystals due to secondary nucleation and shapeless amorphous forms were observed according to the alteration in the solution to ILs ratio. Accordingly, the ability of ILs as a relevant anti-solvent for the selective crystallization of a single compound from a natural product was assessed through the study. Furthermore, the applicability of ILs as crystal engineering solvents are expected to modify both the solid state and the crystal morphology of natural compounds, which can influence drug manufacturability, dissolution rate, and bioavailability.