Journal articles: 'Crystallisation processes'

1

Batstone, J. L., and C. Hayzelden. "Microscopic Processes in Crystallisation." Solid State Phenomena 37-38 (March 1994): 257–68. http://dx.doi.org/10.4028/www.scientific.net/ssp.37-38.257.

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Koulountzios, Panagiotis, Tomasz Rymarczyk, and Manuchehr Soleimani. "Ultrasonic Time-of-Flight Computed Tomography for Investigation of Batch Crystallisation Processes." Sensors 21, no. 2 (January 18, 2021): 639. http://dx.doi.org/10.3390/s21020639.

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Crystallisation is a crucial step in many industrial processes. Many sensors are being investigated for monitoring such processes to enhance the efficiency of them. Ultrasound techniques have been used for particle sizing characterization of liquid suspensions, in crystallisation process. An ultrasound tomography system with an array of ultrasound sensors can provide spatial information inside the process when compared to single-measurement systems. In this study, the batch crystallisation experiments have been conducted in a lab-scale reactor in calcium carbonate crystallisation. Real-time ultrasound tomographic imaging is done via a contactless ultrasound tomography sensor array. The effect of the injection rate and the stirring speed was considered as two control parameters in these crystallisation functions. Transmission mode ultrasound tomography comprises 32 piezoelectric transducers with central frequency of 40 kHz has been used. The process-based experimental investigation shows the capability of the proposed ultrasound tomography system for crystallisation process monitoring. Information on process dynamics, as well as process malfunction, can be obtained via the ultrasound tomography system.

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Andelman, T., M. C. Tan, and R. E. Riman. "Thermochemical engineering of hydrothermal crystallisation processes." Materials Research Innovations 14, no. 1 (February 2010): 9–15. http://dx.doi.org/10.1179/143307510x12599329343123.

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Zhao, Yanlin, Mi Wang, and Robert B. Hammond. "Characterization of crystallisation processes with electrical impedance spectroscopy." Nuclear Engineering and Design 241, no. 6 (June 2011): 1938–44. http://dx.doi.org/10.1016/j.nucengdes.2011.01.001.

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Robertson, Karen, and Chick Wilson. "A novel open tubular continuous crystalliser: design and evaluation." Acta Crystallographica Section A Foundations and Advances 70, a1 (August 5, 2014): C1182. http://dx.doi.org/10.1107/s2053273314088172.

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The ability to continuously manufacture products can be of huge benefit to industry as it can reduce waste and capital expenditure. Continuous crystallisation has received tepid interest for many years but has come to the fore recently as it holds the potential for a radical transformation in the way crystalline products are manufactured, leading to the development method being embraced by major industries such as pharmaceuticals. In addition to the financial benefits offered by continuous crystallisation over conventional batch methods, a higher level of control over the crystallisation process can also be achieved – allowing improved, more consistent particle attributes to be obtained in the crystallisation process. This control is in part a consequence of the smaller volumes involved in continuous crystallisation, which also has the advantage of reducing any hazards associated with the materials being processed. By using smaller volumes, the mixing efficacy is inherently increased which reduces any disparity between local environments, thereby allowing kinetics to dictate the nature of the products. The EPSRC Centre for Innovative Manufacturing in Continuous Manufacturing and Crystallisation (CMAC [1]) in the UK is a collaborative national initiative to further the knowledge base and understanding of all aspects relating to continuous crystallisation and its use in the manufacturing of crystalline particulate products. In this work we present the design and construction of a novel continuous crystalliser and its evaluation using various model systems such as calcium carbonate (polymorph control [2]) and Bourne reactions (mixing efficacy [3]). The crystalliser will then be used in the co-crystallisation of agrichemical and pharmaceutical compounds with co-formers in an effort to optimise the solid-state properties of these materials such as solubility. Various aspects of the evaluation of the design of the new crystalliser will be presented with reference to these trials, and assessed critically with respect to evolution of this design and potential implementation in manufacturing processes.

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Ghosh, G., and F. R. Chen. "Crystallisation kinetics and microstructural evolution of Ni24Zr76 amorphous alloy." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 4 (August 1990): 150–51. http://dx.doi.org/10.1017/s0424820100173881.

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Apart from technological applications, scientifically amorphous —> crystal transformation is very important in understanding the atomic processes involved. For in-depth understanding of the crystallisation process, it is necessary to employ a combination of a number of experimental techniques. In this investigation, the details of the crystallisation of Ni24Zr76 amorphous alloy has been studied by differential scanning calorimtry (DSC), transmission electron microscopy (TEM) and high-resolution electron microscopy (HREM). This amorphous alloy undergoes eutectic crystallisation i.e., it transforms to (α-Zr) + NiZr2 crystals. It is our interest to study the kinetics of the crystallisation as well as the different steps involved in the evolution of equilibrium microstructure.Ribbons of 2-3 mm wide and 25-30 μm thick were produced by melt-spinning technique. Dynamic as well as isothermal crystallisation were studied in a Du-pont DSC 910 cell coupled with computer controlled thermal analyser (TA9900) having system control and data acquisition capabilities.

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Mantovani, M. S. M., and C. J. Hawkesworth. "An inversion approach to assimilation and fractional crystallisation processes." Contributions to Mineralogy and Petrology 105, no. 3 (August 1990): 289–302. http://dx.doi.org/10.1007/bf00306540.

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Bain, Jennifer, Christopher J. Legge, Deborah L. Beattie, Annie Sahota, Catherine Dirks, Joseph R. Lovett, and Sarah S. Staniland. "A biomimetic magnetosome: formation of iron oxide within carboxylic acid terminated polymersomes." Nanoscale 11, no. 24 (2019): 11617–25. http://dx.doi.org/10.1039/c9nr00498j.

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Mix, Andreas, Jan-Hendrik Lamm, Jan Schwabedissen, Erich Gebel, Hans-Georg Stammler, and Norbert W. Mitzel. "Monitoring dynamic pre-crystallization aggregation processes in solution by VT-DOSY-NMR spectroscopy." Chemical Communications 58, no. 21 (2022): 3465–68. http://dx.doi.org/10.1039/d1cc05925d.

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Hydrodynamic radii of pyridine (Py) and tetrafluoroiodopyridine (ITFP), measured by VT-DOSY NMR experiments, tell us how the aggregate formation, driven by halogen-bonding, and ulti-mately crystallisation, occurs.

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Bernardo, Enrico, Giovanni Scarinci, and S. Hreglich. "Monolithic and Cellular Sintered Glass-Ceramics from Wastes." Advances in Science and Technology 45 (October 2006): 596–601. http://dx.doi.org/10.4028/www.scientific.net/ast.45.596.

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Several kinds of wastes have been converted into glasses, successively powdered and sintered with simultaneous crystallisation. The employed “sinter-crystallisation” process was useful to obtain glass-ceramics with particular crystal phases (sometimes un-accessible from traditional nucleation/crystal growth treatments, like feldspar crystals). Conventional pressing of fine glass powders led to monoliths, after sintering, with remarkable mechanical properties (for example bending strength exceeding 100 MPa), useful for tile applications; replication processes, by employing sacrificial polymeric materials, after the same thermal treatment employed for the monoliths, led to open-celled glass-ceramic foams, useful for filtering applications. The enhanced specific surface due to porosity was found to have a positive effect on crystallisation.

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Klapwijk, Anneke, Lynne Thomas, and Chick Wilson. "Towards continuous crystallisation of layered and disordered solid forms." Acta Crystallographica Section A Foundations and Advances 70, a1 (August 5, 2014): C545. http://dx.doi.org/10.1107/s2053273314094546.

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Crystallisation is a vital step in the manufacture of many pharmaceuticals and fine chemicals, producing solids in a form ideal for downstream processes. Unlike others, these industries have not kept pace with advances in continuous production and for centuries industrial crystallisation has operated as a batch process, relying heavily on stirred tank reactors which bring batch to batch variations and limited control over particle attributes. Continuous crystallisation can offer improved product quality, less waste and access to new products more efficiently. One such particle attribute is the presence of molecular disorder in crystalline materials where different ratios of disordered components may show different physical properties [1]. However, disorder can be difficult to control and characterise so has not to date been widely exploited for achieving optimised properties. Multi-component crystallisation can be used to encourage orientational disorder and layering within the crystal lattice by appropriate choice of co-former and by utilising the principles of crystal engineering. The research being presented aims to systematically study disordered and layered materials. Systems that exhibit these characteristics will be discussed structurally, together with results from transferring production of these materials from evaporative to cooling crystallisation, frequently a key first step in achieving crystallisation in a continuous flow environment. In addition, the structural attributes of the particles produced will be correlated with different physical properties such as solubility and compressibility [2].

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Carotenuto, Luigi, Chiara Piccolo, Dario Castagnolo, Marcello Lappa, Alessandra Tortora, and Juan Manuel Garcìa-Ruiz. "Experimental observations and numerical modelling of diffusion-driven crystallisation processes." Acta Crystallographica Section D Biological Crystallography 58, no. 10 (September 26, 2002): 1628–32. http://dx.doi.org/10.1107/s0907444902014440.

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13

Erdmann, Saskia, D. Barrie Clarke, and Michael A. MacDonald. "Origin of chemically zoned and unzoned cordierites from the South Mountain and Musquodoboit Batholiths, Nova Scotia." Earth and Environmental Science Transactions of the Royal Society of Edinburgh 95, no. 1-2 (March 2004): 99–110. http://dx.doi.org/10.1017/s026359330000095x.

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ABSTRACTTextural relations and chemical zoning of cordierites in granites act as sensitive recorders of the conditions of their crystallisation history and underlying magma chamber processes. In this contribution, we present new data on texturally distinct and variably zoned cordierites from the late-Devonian, granitic South Mountain and Musquodoboit Batholiths, and infer the conditions of their formation. Using a combined textural (grain size, grain shape and inclusion relationships) and chemical (major element composition and compositional zoning) classification, we recognise the following six cordierite types: CG1/TT1, anhedral to subhedral macrocrysts with random inclusions and patchy normal zoning; CG2a/TT2, euhedral to subhedral macrocrysts with random inclusions and normal zoning; CG2b/TT2, euhedral to subhedral macrocrysts with random or oriented inclusions, and oscillatory zoning; CG3a/TT3, subhedral to euhedral microcrysts with no inclusions and reverse zoning; CG3b/TT4, euhedral macrocrysts with no inclusions and no zoning; and CG4/TT5, anhedral macrocrysts with random inclusions and normal zoning. The textural criteria suggest that these cordierites formed as a product of cotectic crystallisation from a melt, or as the result of a peritectic reaction involving country-rock material. The combined chemical and textural criteria suggest that: (1) normal zoning results from cotectic crystallisation during cooling, cotectic overgrowths on grains formed in a peritectic reaction with country-rock material, or cation exchange with a fluid; (2) oscillatory zoning results from cotectic crystallisation during variations in XMg of the silicate melt following magma replenishment; (3) reverse zoning results from crystallisation during pressure quenching; and (4) the unzoned cordierite results from cotectic crystallisation under fluid-rich conditions.

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Poole, Graeme M., Roland Stumpf, and Mark Rehkämper. "New methods for determination of the mass-independent and mass-dependent platinum isotope compositions of iron meteorites by MC-ICP-MS." Journal of Analytical Atomic Spectrometry 37, no. 4 (2022): 783–94. http://dx.doi.org/10.1039/d1ja00468a.

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We have developed methods to accurately determine the platinum isotope compositions of iron meteorites. These can be used to investigate processes of planetary formation and evolution, including accretion and core crystallisation.

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Scaillet, Bruno, Alan Whittington, Caroline Martel, Michel Pichavant, and François Holtz. "Phase equilibrium constraints on the viscosity of silicic magmas II: implications for mafic–silicic mixing processes." Earth and Environmental Science Transactions of the Royal Society of Edinburgh 91, no. 1-2 (2000): 61–72. http://dx.doi.org/10.1017/s026359330000729x.

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Isobaric crystallisation paths obtained from phase equilibrium experiments show that, whereas in rhyolitic compositions melt fraction trends are distinctly eutectic, dacitic and more mafic compositions have their crystallinities linearly correlated with temperatures. As a consequence, the viscosities of the latter continuously increase on cooling, whereas for the former they remain constant or even decrease during 80% of the crystallisation interval, which opens new perspectives for the fluid dynamical modelling of felsic magma chambers. Given the typical dyke widths observed for basaltic magmas, results of analogue modelling predict that injection of mafic magmas into crystallising intermediate to silicic plutons under pre-eruption conditions cannot yield homogeneous composition. Homogenisation can occur, however, if injection takes place in the early stages of magmatic evolution (i.e. at near liquidus conditions) but only in magmas of dacitic or more mafic composition. More generally, the potential for efficient mixing between silicic and mafic magmas sharing large interfaces at upper crustal levels is greater for dry basalts than for wet ones. At the other extreme, small mafic enclaves found in many granitoids behave essentially as rigid objects during a substantial part of the crystallisation interval of the host magmas, which implies that finite strain analyses carried out on such markers can give only a minimum estimate of the total amount of strain experienced by the host pluton. Mafic enclaves carried by granitic magmas behave as passive markers only at near solidus conditions, typically when the host granitic magma shows near-solid behaviour. Thus they cannot be used as fossil indicators of direction of magmatic flow.

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Sögütoglu, Leyla-Cann, René R. E. Steendam, Hugo Meekes, Elias Vlieg, and Floris P. J. T. Rutjes. "Viedma ripening: a reliable crystallisation method to reach single chirality." Chemical Society Reviews 44, no. 19 (2015): 6723–32. http://dx.doi.org/10.1039/c5cs00196j.

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This tutorial review covers the basic principles behind asymmetric crystallisation processes, with an emphasis on Viedma ripening, and shows that to date many organic molecules can be obtained this way in enantiopure solid form.

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Rapiejko, C., B. Pisarek, E. Czekaj, and T. Pacyniak. "Analysis of Am60 and Az91 Alloy Crystallisation in Ceramic Moulds by Thermal Derivative Analysis (Tda)/ Analiza Krystalizacji Stopów Am60 I Az91 W Formie Ceramicznej Metodą Analizy Termiczno-Derywacyjnej (Atd)." Archives of Metallurgy and Materials 59, no. 4 (December 1, 2014): 1449–55. http://dx.doi.org/10.2478/amm-2014-0246.

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Abstract The work presents the test results of the crystallisation and cooling of magnesium alloys: AM60 and AZ91, with the use of the TDA method. The tested alloys were cast into ceramic shells heated up to 180°C, produced according to the technology of the shell production in the investment casting method. The TDA method was applied to record and characterize the thermal effect resulting from the phase transformations occurring during the crystallisation of magnesium alloys. The kinetics and dynamics of the thermal processes of the crystallisation of AM60 and AZ91 in the ceramic shells were determined. Metallographic tests were performed with the use of an optical microscope as well as scanning microscopy, together with the EDS chemical analysis of the phases present in the tested casts. A comparison of these test results with the thermal effect recorded by way of the TDA method was made.

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Chappell, B. W. "Compositional variation within granite suites of the Lachlan Fold Belt: its causes and implications for the physical state of granite magma." Earth and Environmental Science Transactions of the Royal Society of Edinburgh 87, no. 1-2 (1996): 159–70. http://dx.doi.org/10.1017/s026359330000657x.

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ABSTRACT:Granites within suites share compositional properties that reflect features of their source rocks. Variation within suites results dominantly from crystal fractionation, either of restite crystals entrained from the source, or by the fractional crystallisation of precipitated crystals. At least in the Lachlan Fold Belt, the processes of magma mixing, assimilation or hydrothermal alteration were insignificant in producing the major compositional variations within suites. Fractional crystallisation produced the complete variation in only one significant group of rocks of that area, the relatively high temperature Boggy Plain Supersuite. Modelling of Sr, Ba and Rb variations in the I-type Glenbog and Moruya suites and the S-type Bullenbalong Suite shows that variation within those suites cannot be the result of fractional crystallisation, but can be readily accounted for by restite fractionation. Direct evidence for the dominance of restite fractionation includes the close chemical equivalence of some plutonic and volcanic rocks, the presence of plagioclase cores that were not derived from a mingled mafic component, and the occurrence of older cores in many zircon crystals. In the Lachlan Fold Belt, granite suites typically evolved through a protracted phase of restite fractionation, with a brief episode of fractional crystallisation sometimes evident in the most felsic rocks. Evolution of the S-type Koetong Suite passed at about 69% SiO2 from a stage dominated by restite separation to one of fractional crystallisation. Other suites exist where felsic rocks evolved in the same way, but the more mafic rocks are absent. In terranes in which tonalitic rocks formed at high temperatures are more common, fractional crystallisation would be a more important process than was the case for the Lachlan Fold Belt.

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Bolrão, Daniela Paz, Maxim D. Ballmer, Adrien Morison, Antoine B. Rozel, Patrick Sanan, Stéphane Labrosse, and Paul J. Tackley. "Timescales of chemical equilibrium between the convecting solid mantle and over- and underlying magma oceans." Solid Earth 12, no. 2 (February 22, 2021): 421–37. http://dx.doi.org/10.5194/se-12-421-2021.

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Abstract. After accretion and formation, terrestrial planets go through at least one magma ocean episode. As the magma ocean crystallises, it creates the first layer of solid rocky mantle. Two different scenarios of magma ocean crystallisation involve that the solid mantle either (1) first appears at the core–mantle boundary and grows upwards or (2) appears at mid-mantle depth and grows in both directions. Regardless of the magma ocean freezing scenario, the composition of the solid mantle and liquid reservoirs continuously change due to fractional crystallisation. This chemical fractionation has important implications for the long-term thermo-chemical evolution of the mantle as well as its present-day dynamics and composition. In this work, we use numerical models to study convection in a solid mantle bounded at one or both boundaries by magma ocean(s) and, in particular, the related consequences for large-scale chemical fractionation. We use a parameterisation of fractional crystallisation of the magma ocean(s) and (re)melting of solid material at the interface between these reservoirs. When these crystallisation and remelting processes are taken into account, convection in the solid mantle occurs readily and is dominated by large wavelengths. Related material transfer across the mantle–magma ocean boundaries promotes chemical equilibrium and prevents extreme enrichment of the last-stage magma ocean (as would otherwise occur due to pure fractional crystallisation). The timescale of equilibration depends on the convective vigour of mantle convection and on the efficiency of material transfer between the solid mantle and magma ocean(s). For Earth, this timescale is comparable to that of magma ocean crystallisation suggested in previous studies (Lebrun et al., 2013), which may explain why the Earth's mantle is rather homogeneous in composition, as supported by geophysical constraints.

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Du, W., A. J. Cruz-Cabeza, S. Woutersen, R. J. Davey, and Q. Yin. "Can the study of self-assembly in solution lead to a good model for the nucleation pathway? The case of tolfenamic acid." Chemical Science 6, no. 6 (2015): 3515–24. http://dx.doi.org/10.1039/c5sc00522a.

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To further our understanding of the role of solution chemistry in directing nucleation processes new experimental and computational data are presented on the solution and crystallisation chemistry of tolfenamic acid (TA), a benchmark polymorphic compound.

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Campbell, J., and A. G. Livingston. "The Effect of Concentration Polarisation on Organic Solvent Nanofiltration Crystallisation Processes." Procedia Engineering 44 (2012): 241–43. http://dx.doi.org/10.1016/j.proeng.2012.08.373.

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22

Tachtatzis, Christos, Rachel Sheridan, Craig Michie, Robert C. Atkinson, Alison Cleary, Jerzy Dziewierz, Ivan Andonovic, Naomi E. B. Briggs, Alastair J. Florence, and Jan Sefcik. "Image-based monitoring for early detection of fouling in crystallisation processes." Chemical Engineering Science 133 (September 2015): 82–90. http://dx.doi.org/10.1016/j.ces.2015.01.038.

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23

Muydinov, Ruslan, Alexander Steigert, Markus Wollgarten, Paweł Michałowski, Ulrike Bloeck, Andreas Pflug, Darja Erfurt, et al. "Crystallisation Phenomena of In2O3:H Films." Materials 12, no. 2 (January 15, 2019): 266. http://dx.doi.org/10.3390/ma12020266.

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The crystallisation of sputter-deposited, amorphous In2O3:H films was investigated. The influence of deposition and crystallisation parameters onto crystallinity and electron hall mobility was explored. Significant precipitation of metallic indium was discovered in the crystallised films by electron energy loss spectroscopy. Melting of metallic indium at ~160 °C was suggested to promote primary crystallisation of the amorphous In2O3:H films. The presence of hydroxyl was ascribed to be responsible for the recrystallization and grain growth accompanying the inter-grain In-O-In bounding. Metallic indium was suggested to provide an excess of free electrons in as-deposited In2O3 and In2O3:H films. According to the ultraviolet photoelectron spectroscopy, the work function of In2O3:H increased during crystallisation from 4 eV to 4.4 eV, which corresponds to the oxidation process. Furthermore, transparency simultaneously increased in the infraredspectral region. Water was queried to oxidise metallic indium in UHV at higher temperature as compared to oxygen in ambient air. Secondary ion mass-spectroscopy results revealed that the former process takes place mostly within the top ~50 nm. The optical band gap of In2O3:H increased by about 0.2 eV during annealing, indicating a doping effect. This was considered as a likely intra-grain phenomenon caused by both (In0)O•• and (OH−)O• point defects. The inconsistencies in understanding of In2O3:H crystallisation, which existed in the literature so far, were considered and explained by the multiplicity and disequilibrium of the processes running simultaneously.

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English, Niall J. "Molecular Simulation of Crystallisation in External Electric Fields: A Review." Crystals 11, no. 3 (March 22, 2021): 316. http://dx.doi.org/10.3390/cryst11030316.

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Elucidating the underlying mechanisms of molecular solidification in both homo- and hetero-geneous systems is of paramount importance for a large swathe of natural phenomena (whether on Earth or throughout the Universe), as well as a whole litany of industrial processes. One lesser-studied aspect of these disorder-order transitions is the effect of external applied fields, shifting both thermodynamic driving forces and underlying kinetics, and, indeed, fundamental mechanisms themselves. Perhaps this is nowhere more apparent than in the case of externally-applied electric fields, where there has been a gradually increasing number of reports in recent years of electro-manipulated crystallisation imparted by such electric fields. Drawing motivations from both natural phenomena, state-of-the-art experiments and, indeed, industrial applications, this review focusses on how non-equilibrium molecular simulation has helped to elucidate crystallisation phenomena from a microscopic perspective, as well as offering an important, predictive molecular-design approach with which to further refine in-field-crystallisation operations.

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Yurtmen, S., and G. Rowbotham. "A scanning electron microscope study of post-depositional changes in the northeast Niğde ignimbrites, South Central Anatolia, Turkey." Mineralogical Magazine 63, no. 1 (February 1999): 131–41. http://dx.doi.org/10.1180/002646199548259.

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AbstractThe ignimbrites of the northeast Niğde area, which are subdivided into the Lower, Middle and Upper ignimbrites on the basis of their compositional and stratigraphical characteristics, display textural variations from the base to the top. A large proportion of these ignimbrites have been altered and recrystallized by the processes of compaction, welding and devitrification, and as a result of volatile movement. The alteration and recrystallization processes include four stages: hydration, glassy and spherulitic stages accompanied by vapour-phase crystallisation. In the early phases of devitrification, detailed shard shapes are easily recognisable with the scanning electron microscope, but as alteration proceeds clarity of detail disappears because compaction results in collapse of the structure of the rock. Spherulitic and vapour-phase crystallisation usually involves the growth of alkali feldspar and cristobalite. These later stages are more common in the Upper Ignimbrite than the Middle and Lower ignimbrites.

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McGinty, John, Magdalene W. S. Chong, Andrew Manson, Cameron J. Brown, Alison Nordon, and Jan Sefcik. "Effect of Process Conditions on Particle Size and Shape in Continuous Antisolvent Crystallisation of Lovastatin." Crystals 10, no. 10 (October 12, 2020): 925. http://dx.doi.org/10.3390/cryst10100925.

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Lovastatin crystals often exhibit an undesirable needle-like morphology. Several studies have shown how a needle-like morphology can be modified in antisolvent crystallisation with the use of additives, but there is much less experimental work demonstrating crystal shape modification without the use of additives. In this study, a series of unseeded continuous antisolvent crystallisation experiments were conducted with the process conditions of supersaturation, total flow rate, and ultrasound level being varied to determine their effects on crystal size and shape. This experimental work involved identifying acetone/water as the most suitable solvent/antisolvent system, assessing lovastatin nucleation behaviour by means of induction time measurements, and then designing and implementing the continuous antisolvent crystallisation experiments. It was found that in order to produce the smallest and least needle-like particles, the maximum total flow rate and supersaturation had to be combined with the application of ultrasound. These results should aid development of pharmaceutical manufacturing processes where the ability to control particle size and shape would allow for optimisation of crystal isolation and more efficient downstream processing.

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Benavente, David, Marli de Jongh, and Juan Carlos Cañaveras. "Weathering Processes and Mechanisms Caused by Capillary Waters and Pigeon Droppings on Porous Limestones." Minerals 11, no. 1 (December 25, 2020): 18. http://dx.doi.org/10.3390/min11010018.

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This investigation studies the physical and chemical effect of salt weathering on biocalcarenites and biocalcrudites in the Basilica of Our Lady of Succour (Aspe, Spain). Weathering patterns are the result of salty rising capillary water and water lixiviated from pigeon droppings. Surface modifications and features induced by material loss are observable in the monument. Formation of gypsum, hexahydrite, halite, aphthitalite and arcanite is associated with rising capillary water, and niter, hydroxyapatite, brushite, struvite, weddellite, oxammite and halite with pigeon droppings. Humberstonite is related to the interaction of both types of waters. Analysis of crystal shapes reveals different saturation degree conditions. Single salts show non-equilibrium shapes, implying higher crystallisation pressures. Single salts have undergone dissolution and/or dehydration processes enhancing the deterioration process, particularly in the presence of magnesium sulphate. Double salts (humberstonite) have crystals corresponding to near-equilibrium form, implying lower crystallisation pressures. This geochemical study suggests salts precipitate via incongruent reactions rather than congruent precipitation, where hexahydrite is the precursor and limiting reactant of humberstonite. Chemical dissolution of limestone is driven mainly by the presence of acidic water lixiviated from pigeon droppings and is a critical weathering process affecting the most valuable architectural elements present in the façades.

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Toplis, Michael J., Guy Libourel, and Michael R. Carroll. "The role of phosphorus in crystallisation processes of basalt: An experimental study." Geochimica et Cosmochimica Acta 58, no. 2 (January 1994): 797–810. http://dx.doi.org/10.1016/0016-7037(94)90506-1.

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Gardner, M. F., V. R. Troll, G. Hart, R. Gertisser, J. A. Wolff, and J. A. Gamble. "Shallow-level processes at Anak Krakatau: Crystallisation and late stage crustal contamination." Geochimica et Cosmochimica Acta 70, no. 18 (August 2006): A194. http://dx.doi.org/10.1016/j.gca.2006.06.391.

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30

Gich, M., T. Gloriant, S. Suriñach, A. L. Greer, and M. D. Baró. "Glass forming ability and crystallisation processes within the Al–Ni–Sm system." Journal of Non-Crystalline Solids 289, no. 1-3 (August 2001): 214–20. http://dx.doi.org/10.1016/s0022-3093(01)00650-0.

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Baker, Mike, Zhiyi Cao, David Dale, Peter Erk, Leslie Ford, Heidi Groen, David Latham, et al. "On-Line Analytical Techniques for Monitoring Crystallisation Processes of Organic Speciality Chemicals." Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals 356, no. 1 (February 1, 2001): 273–87. http://dx.doi.org/10.1080/10587250108023707.

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32

Thompson, Stephen P., Claudia Verrienti, Sergio Fonti, Vincenzo Orofino, and Armando Blanco. "Crystallisation processes in cosmic silicates: Laboratory progress towards understanding structural–spectral relationships." Advances in Space Research 39, no. 3 (January 2007): 375–91. http://dx.doi.org/10.1016/j.asr.2005.05.009.

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33

Kupka, Anna, Hermann Gies, and Klaus Merz. "Influence on Crystallisation Process of Amino Acids from Solution." Acta Crystallographica Section A Foundations and Advances 70, a1 (August 5, 2014): C546. http://dx.doi.org/10.1107/s2053273314094534.

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The famous Miller experiment to model the primordial soup demonstrated that amino acids can form spontaneously as the essential building blocks of life in solutions. It is, however, still an open question how self-recognition processes influence the transformation of these spontaneously formed amino acids in solvents into higher ordered structures in the solid state, thereby creating chiral materials and catalytically competent structures. The understanding of the first steps of molecular self-assembly processes in such environments will thus give important clues towards the understanding of biological evolution. Most of intermolecular interactions are not very strong and their formation is related to and affected by small changes in the molecular structure and the crystallisation conditions. Continuing our investigations on aggregation of substituted aromatic molecules in the solid state, we studied the influence and boundaries of weak directing substituents like deuterium on the aggregation of small molecules. Hydrogen/deuterium (H/D)-exchange, the smallest possible modification of a molecule, is generally seen as a non dominating parameter in the formation of crystal structures of chemical compounds. On the other hand, it could already be shown that the aggregation of molecules in the solid state of polymorphic N-heterocycle systems like pyridine-N-oxide or acridine can be very sensitive to small changes of the isotopic substitution pattern of the selected molecules. Within our project, the molecular aggregation of amino acids in solution with the formation of molecular aggregates and pre-nucleation clusters in deuterated and non-deuterated systems, and in particular the role of the solvent in these processes, will be studied in both experiment and theory.

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Nazzareni, Sabrina, Daniele Morgavi, Maurizio Petrelli, Omar Bartoli, and Diego Perugini. "Magmatic Processes at Euganean Hills (Veneto Volcanic Province, Italy): Clinopyroxene Investigation to Unravel Magmatic Interactions." Geosciences 12, no. 3 (February 25, 2022): 108. http://dx.doi.org/10.3390/geosciences12030108.

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The Euganean Hills (NE Italy) magmatic district represents the final volcanic activity of the Veneto Volcanic Province. Alkaline to subalkaline magmatic suite dominated by intermediate to felsic volcanic rocks characterises the latest volcanic activity of the Euganean Hills. Magmatic (intrusive and volcanic) enclaves are common in Euganean Hills trachytes. We used the ability of clinopyroxene to record variations of P, T, and fO2 to reconstruct the geological history of the volcanic enclaves and trachytic host. Despite similar major and trace elements composition, clinopyroxene from host is higher in Ca and Na (and Fe3+) and lower in Mg than enclaves and is slightly enriched in trace elements but with the same pattern distribution. Minor differences in geochemistry and crystal structure of clinopyroxene from enclaves and trachytic host suggest similar parental magmas that differs by small degrees of fractional crystallisation. Clinopyroxene geobarometry performed combining X-ray diffraction with mineral geochemistry for volcanic enclaves–trachytic host combined with amphibole geobarometry for intrusive enclaves and crystal mushes points to a crystallisation pressure range between 4.8–2.0 kbars. Our data support the model of a complex system of magma chambers at intermediate to shallow crustal level where mafic magma accumulated, evolved by fractionation processes and mixed.

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35

Majzlan, Juraj. "Processes of metastable-mineral formation in oxidation zones and mine waste." Mineralogical Magazine 84, no. 3 (March 18, 2020): 367–75. http://dx.doi.org/10.1180/mgm.2020.19.

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AbstractOxidation zones and mine wastes are metal-rich, near-surface environments, natural and man-made critical zones of ore deposits, respectively. They contain a number of minerals which, despite their metastability, occur consistently and in abundance. Field studies, presented as examples in this work, show that metastable minerals form not only directly from aqueous solutions, but also from more complex precursors, such as nanoparticles, gels, X-ray amorphous solids, or clusters. Initial precipitation of metastable phases and their conversion to stable phases is described by the Ostwald's step rule. Thermodynamic data show that there is a tendency, but no rule, that structurally more complex phases are also thermodynamically more stable. The Ostwald's step rule could then state that the initial metastable phases are structurally simple and easily assembled from aqueous solutions, nanoparticles, gels, disordered solids, or clusters. The structural similarity of the precursor and the forming phase is a kinetic factor favouring the crystallisation of the new phase. Calculation of saturation indices for mine drainage solutions show that they are mostly supersaturated with respect to the stable phases and the aqueous concentrations are sufficient to precipitate metastable minerals. In our fieldwork, we often encounter gelatinous substances with copper, manganese or tungsten that slowly convert to metastable oxysalt minerals. Another possibility is the crystallisation of various metastable minerals from solid, homogeneous ‘resins’ that are X-ray amorphous. Minerals typical for near-surface environments may be stabilised by their surface energy at high specific surface areas. For example, ferrihydrite is often described as a metastable phase but can be shown to be stable with respect to nanosised hematite.

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Dmitriev, A. A., Alexander V. Evteev, V. M. Ievlev, A. T. Kosilov, and Elena V. Levchenko. "Simulation of the Oriented Crystallisation of Cu/Pd(001) Amorphous Film." Solid State Phenomena 115 (August 2006): 311–14. http://dx.doi.org/10.4028/www.scientific.net/ssp.115.311.

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Crystallisation processes of amorphous Cu-film on Pd(001) substrate have been investigated by molecular dynamics method. It has been established that the formed structure has tetragonal distortions; the elastic stresses caused by dimensional misfit of crystal lattices of the substrate and the film lead to the formation of complex defect structure changing during the annealing.

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37

Stach, R., P. Krebs, F. Jones, and B. Mizaikoff. "Observing non-classical crystallisation processes in gypsum via infrared attenuated total reflectance spectroscopy." CrystEngComm 19, no. 1 (2017): 14–17. http://dx.doi.org/10.1039/c6ce01787h.

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38

Kwapuliński, P., J. Rasek, Z. Stokłosa, G. Haneczok, and M. Gigla. "Structural relaxation and crystallisation processes in FeCu1XSi13B9 (X=Mo, Cr, Zr) amorphous alloys." Journal of Magnetism and Magnetic Materials 215-216 (June 2000): 334–36. http://dx.doi.org/10.1016/s0304-8853(00)00150-5.

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39

Micovic, Jovana, Thorsten Beierling, Philip Lutze, Gabriele Sadowski, and Andrzej Górak. "Design of hybrid distillation/melt crystallisation processes for separation of close boiling mixtures." Chemical Engineering and Processing: Process Intensification 67 (May 2013): 16–24. http://dx.doi.org/10.1016/j.cep.2012.07.012.

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Schmidt, Bernd, Jeegna Patel, Francois X. Ricard, Clemens M. Brechtelsbauer, and Norman Lewis. "Application of Process Modelling Tools in the Scale-Up of Pharmaceutical Crystallisation Processes." Organic Process Research & Development 8, no. 6 (November 2004): 998–1008. http://dx.doi.org/10.1021/op040013n.

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41

Boltersdorf, U., G. Deerberg, S. Schlüter, and P. M. Weinspach. "Stirred Tank Reactors in Multiphase Operation-Simulation of Catalytic Reactions and Crystallisation Processes." Chemie Ingenieur Technik 73, no. 6 (June 2001): 740. http://dx.doi.org/10.1002/1522-2640(200106)73:6<740::aid-cite7401111>3.0.co;2-3.

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42

Packter, A., and W. O. S. Doherty. "The annealing of alkaline-earth metal polymetaphosphate powders (I). Crystallisation and sintering processes." Crystal Research and Technology 24, no. 12 (December 1989): 1207–14. http://dx.doi.org/10.1002/crat.2170241205.

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43

Hatcher, Lauren E., Ayrton J. Burgess, Pollyanna Payne, and Chick C. Wilson. "From structure to crystallisation and pharmaceutical manufacturing: the CSD in CMAC workflows." CrystEngComm 22, no. 43 (2020): 7475–89. http://dx.doi.org/10.1039/d0ce00898b.

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Kirichek, Oleg, Alan Soper, Boris Dzyuba, Sam Callear, and Barry Fuller. "Strong Isotope Effects on Melting Dynamics and Ice Crystallisation Processes in Cryo Vitrification Solutions." PLOS ONE 10, no. 3 (March 27, 2015): e0120611. http://dx.doi.org/10.1371/journal.pone.0120611.

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Jünemann, S., A. Jupke, F. Giesselmann, A. Epping, and H. Schmidt-Traub. "Optimal Design of Downstream Processes by Considering Interactions between Chromatography and Crystallisation in Biotechnology." Chemie Ingenieur Technik 73, no. 6 (June 2001): 734. http://dx.doi.org/10.1002/1522-2640(200106)73:6<734::aid-cite7341111>3.0.co;2-s.

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Sanzida, Nahid, and Zoltan K. Nagy. "Iterative learning control for the systematic design of supersaturation controlled batch cooling crystallisation processes." Computers & Chemical Engineering 59 (December 2013): 111–21. http://dx.doi.org/10.1016/j.compchemeng.2013.05.027.

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Aamir, E., Z. K. Nagy, and C. D. Rielly. "Optimal seed recipe design for crystal size distribution control for batch cooling crystallisation processes." Chemical Engineering Science 65, no. 11 (June 2010): 3602–14. http://dx.doi.org/10.1016/j.ces.2010.02.051.

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Martínez-Martínez, Javier, Anna Arizzi, and David Benavente. "The Role of Calcite Dissolution and Halite Thermal Expansion as Secondary Salt Weathering Mechanisms of Calcite-Bearing Rocks in Marine Environments." Minerals 11, no. 8 (August 23, 2021): 911. http://dx.doi.org/10.3390/min11080911.

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This research focuses on the analysis of the influence of two secondary salt weathering processes on the durability of rocks exposed to marine environments: chemical dissolution of rock forming minerals and differential thermal expansion between halite and the hosting rock. These processes are scarcely treated in research compared to salt crystallisation. The methodology followed in this paper includes both in situ rock weathering monitoring and laboratory simulations. Four different calcite-bearing rocks (a marble, a microcrystalline limestone and two different calcarenites) were exposed during a year to a marine semiarid environment. Exposed samples show grain detachment, crystal edge corrosion, halite efflorescences and microfissuring. Crystal edge corrosion was also observed after the laboratory simulation during a brine immersion test. Calcite chemical dissolution causes a negligible porosity increase in all the studied rocks, but a significant modification of their pore size distribution. Laboratory simulations also demonstrate the deterioration of salt-saturated rocks during thermal cycles in climatic cabinet. Sharp differences between the linear thermal expansion of both a pure halite crystal and the different studied rocks justify the registered weight loss during the thermal cycles. The feedback between the chemical dissolution and differential thermal expansion, and the salt crystallisation of halite, contribute actively to the rock decay in marine environments.

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Baricco, Marcello, Tanya A. Başer, Gianluca Fiore, Rafael Piccin, Marta Satta, Alberto Castellero, Paola Rizzi, and Livio Battezzati. "Bulk Metallic Glasses." Materials Science Forum 604-605 (October 2008): 229–38. http://dx.doi.org/10.4028/www.scientific.net/msf.604-605.229.

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Rapid quenching techniques have been successfully applied since long time for the preparation of metallic glasses in ribbon form. Only in the recent years, the research activity addressed towards the synthesis of bulk metallic glasses (BMG), in form of ingots with a few millimetres in thickness. These materials can be obtained by casting techniques only for selected alloy compositions, characterised by a particularly high glass-forming tendency. Bulk amorphous alloys are characterised by a low modulus of elasticity and high yielding stress. The usual idea is that amorphous alloys undergo work softening and that deformation is concentrated in shear bands, which might be subjected to geometrical constraints, resulting in a substantial increase in hardness and wear resistance. The mechanical properties can be further improved by crystallisation. In fact, shear bands movement can be contrasted by incorporating a second phase in the material, which may be produced directly by controlled crystallisation. Soft magnetic properties have been obtained in Fe-based systems and they are strongly related to small variations in the microstructure, ranging from a fully amorphous phase to nanocrystalline phases with different crystal size. The high thermal stability of bulk metallic glasses makes possible the compression and shaping processes in the temperature range between glass transition and crystallisation. Aim of this paper is to present recent results on glass formation and properties of bulk metallic glasses with various compositions. Examples will be reported on Zr, Fe, Mg and Pd-based materials, focussing on mechanical and magnetic properties.

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Campbell, Ken, David Clapham, and Kate Thomas. "Use of qunatitative colour measurement as a tool to measure crystallisation processes during formulation development." European Journal of Pharmaceutical Sciences 4 (September 1996): S163. http://dx.doi.org/10.1016/s0928-0987(97)86490-1.

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Journal articles on the topic 'Crystallisation processes'

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