Relevant bibliographies by topics / Crystallisation

Academic literature on the topic 'Crystallisation'

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Published: 4 June 2021
Last updated: 25 May 2024

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Journal articles on the topic "Crystallisation"

1

Coles, Simon J., and Terence L. Threlfall. "A practical guide to the measurement of turbidity curves of cooling crystallisations from solution." CrystEngComm 22, no. 10 (2020): 1865–74. http://dx.doi.org/10.1039/c9ce01622h.

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2

O’Malley, Ciaran, Patrick McArdle, and Andrea Erxleben. "Crystallization from the Gas Phase: Morphology Control, Co-Crystal and Salt Formation." Proceedings 78, no. 1 (December 1, 2020): 1. http://dx.doi.org/10.3390/iecp2020-08797.

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Multicomponent crystallisation is a widely studied technique in pharmaceutical chemistry to enhance physical properties of API’s such as solubility, stability and bioavailability without chemically modifying the drug moiety itself. Methods to produce multicomponent crystals are varied with solution crystallisation being the predominant method. Crystal morphologies also influence an API’s properties with needle shaped crystals dissolving slower and possessing poor flow properties compared to a more equant block shape. In this paper, we discuss the preparation of co-crystals and co-crystal salts of two poorly soluble drugs, pyrimethamine and diflunisal. In particular, we compare production of multicomponent crystals via cosublimation with the more common methods of mechanical grinding and solution crystallisation. Samples are sublimed on a laboratory scale from both ends of standard 15 × 160 mm test tubes sealed under vacuum with two heaters were used to equalize the sublimation rates of the components. We show that a range of multicomponent pharmaceutical crystals can be prepared that are not accessible via solution crystallisation, including polymorphs and ansolvates. In addition to binary systems, ternary crystals can also be obtained via this technique. Various diflunisal co-crystals crystallise as thin needles and we describe the use of tailor-made additives to obtain unprecedented morphology control of gas phase crystal growth. Finally, we discuss the formation of co-crystal salts in the absence of solvent. Salt formation was observed to occur during gas phase crystallisations in accordance with the pKa rule of 3 and modelling studies were carried out to understand the nature of proton transfer in these crystals in the absence of a solvent.
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Yin, Zhichao, Ying Fu, and Qingfeng Chen. "Research progress in recovering phosphorus from wastewater by crystallisation." E3S Web of Conferences 118 (2019): 04031. http://dx.doi.org/10.1051/e3sconf/201911804031.

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Phosphorus removal by crystallisation has the advantages of fast reactions, high efficiency, and recyclable resources, and it has attracted much attention at globally in recent years. With extensive research, its theory and process technology have been continuously improved. Magnesium ammonium phosphate (MAP) crystallisation and calcium hydroxyphosphate (hydroxyapatite, HAP) crystallisation are two common methods for wastewater dephosphorisation, but there are few reviews of these two methods. In this paper, the research results concerning MAP and HAP crystallisation methods are comprehensively reviewed. The reaction principle, influencing factors, and engineering applications of the two products are summarised, and the two crystallisation methods are compared. Finally, the development of future phosphorus crystallisation technology is discussed. These prospects provide a basis for the promotion and application of phosphorus removal by crystallisation.
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Azmi, Nik Salwani Md, Nornizar Anuar, Muhamad Fitri Othman, Noor Fitrah Abu Bakar, and Mohd Nazli Naim. "Electric-Potential-Assisted Crystallisation of L-Isoleucine: A Study of Nucleation Kinetics and Its Associated Parameters." Crystals 11, no. 6 (May 31, 2021): 620. http://dx.doi.org/10.3390/cryst11060620.

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The potential of producing L-isoleucine crystals with the aid of electric potential and its effect on the nucleation kinetics of L-isoleucine were probed using polythermal and isothermal crystallisation techniques, assisted with 5 V, 9 V, and 20 V electric potentials. The polythermal experiments were conducted with cooling rates of 0.1 °C/min–0.7 °C/min, whilst isothermal crystallisation was conducted with a supersaturation of 1.30–1.70, and both were carried out in a 200 mL temperature-controlled jacketed reactor. Prediction of the nucleation rate and its associated parameters for isothermal crystallisation was carried out using a molecular dynamics simulation. In both crystallisation techniques, electric potentials increased the nucleation rate, but the intensity of the electric potential had less impact on the measured parameters. Nucleation rates for 5 V isothermal crystallisation were in the order of 1010 higher than for polythermal crystallisation. Electric potential doubled the nucleation rates for polythermal crystallisation and increased the nucleation rates 12-fold in isothermal crystallisation. The isothermal technique produced the form B polymorph, but mixtures of forms A and B were produced in polythermal crystallisation. The predicted critical number of molecules, N*, and the critical radius, r*, were in good agreement with the experimental data, with a higher predicted nucleation rate in the order of 102.
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Běhálek, Luboš, Jan Novák, Pavel Brdlík, Martin Borůvka, Jiří Habr, and Petr Lenfeld. "Physical Properties and Non-Isothermal Crystallisation Kinetics of Primary Mechanically Recycled Poly(l-lactic acid) and Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)." Polymers 13, no. 19 (October 2, 2021): 3396. http://dx.doi.org/10.3390/polym13193396.

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The physical properties and non-isothermal melt- and cold-crystallisation kinetics of poly (l-lactic acid) (PLLA) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) biobased polymers reprocessed by mechanical milling of moulded specimens and followed injection moulding with up to seven recycling cycles are investigated. Non-isothermal crystallisation kinetics are evaluated by the half-time of crystallisation and a procedure based on the mathematical treatment of DSC cumulative crystallisation curves at their inflection point (Kratochvil-Kelnar method). Thermomechanical recycling of PLLA raised structural changes that resulted in an increase in melt flow properties by up to six times, a decrease in the thermal stability by up to 80 °C, a reduction in the melt half-time crystallisation by up to about 40%, an increase in the melt crystallisation start temperature, and an increase in the maximum melt crystallisation rate (up to 2.7 times). Furthermore, reprocessing after the first recycling cycle caused the elimination of cold crystallisation when cooling at a slow rate. These structural changes also lowered the cold crystallisation temperature without impacting the maximum cold crystallisation rate. The structural changes of reprocessed PHBV had no significant effect on the non-isothermal crystallisation kinetics of this material. Additionally, the thermomechanical behaviour of reprocessed PHBV indicates that the technological waste of this biopolymer is suitable for recycling as a reusable additive to the virgin polymer matrix. In the case of reprocessed PLLA, on the other hand, a significant decrease in tensile and flexural strength (by 22% and 46%, respectively) was detected, which reflected changes within the biobased polymer structure. Apart from the elastic modulus, all the other thermomechanical properties of PLLA dropped down with an increasing level of recycling.
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Yang, Ke, Bing Li, Yanhong Li, Xin Wang, and Xinhui Fan. "Effect of Gd addition on non-isothermal and isothermal crystallisation of Cu–Zr–Al bulk metallic glass." International Journal of Materials Research 112, no. 11 (November 1, 2021): 860–71. http://dx.doi.org/10.1515/ijmr-2021-8421.

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Abstract The crystallisation kinetics of (Cu46Zr46Al8)100–xGdx (x = 0, 2 and 4 at.%) bulk metallic glasses in non-isothermal and isothermal conditions were studied by differential scanning calorimetry and X-ray diffraction. X-ray diffraction analysis shows that the crystallisation product Cu10Zr7 changes to Cu10Zr7 and Cu2Gd in the presence of Gd in non-isothermal and isothermal conditions. Crystallisation activation energy was calculated using the Kissinger and Ozawa methods in non-isothermal conditions and using the Arrhenius model in isothermal conditions. The results show that Gd addition triggers an increase in the energy barrier during crystallisation. The Johnson–Mehl–Avrami model was employed to analyse the crystallisation kinetics in the isothermal condition. The Avrami exponent, n, for Cu46Zr46Al8 is more than 2.5, which demonstrates that the crystallisation is mainly governed by diffusion-controlled three-dimensional growth with increasing nucleation rate. Comparably, n for (Cu46Zr46Al8)98Gd2 and (Cu46Zr46Al8)96Gd4 is 1.5 < n < 2.5, which suggests that the crystallisation is mainly determined by diffusion-controlled three-dimensional growth with decreasing nucleation rate.
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7

Ghosh, Dipankar, Katja Ferfolja, Žygimantas Drabavičius, Jonathan W. Steed, and Krishna K. Damodaran. "Crystal habit modification of Cu(ii) isonicotinate–N-oxide complexes using gel phase crystallisation." New Journal of Chemistry 42, no. 24 (2018): 19963–70. http://dx.doi.org/10.1039/c8nj05036h.

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We report the crystallisation of three forms of the copper(ii) isonicotinate–N-oxide complex and their phase interconversion via solvent-mediated crystal-to-crystal transformation and the selective crystallisation of one form via gel phase crystallisation.
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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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He, Feng, and Qinghua Liu. "Crystal Structure Analysis of Different Flame Retardant Copolymers." Journal of Physics: Conference Series 2468, no. 1 (April 1, 2023): 012043. http://dx.doi.org/10.1088/1742-6596/2468/1/012043.

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Abstract In this paper, through the DSC rising and cooling scanning and non-isothermal crystallization tests of different flame retardant copolymers, the crystallization process of four types of copolymers formed by adding different flame retardants such as CEPPA, DDP, Carbon-dots (gCDs), and MOF materials was studied. Also, the crystallization kinetics and crystal structure were explored. The results showed that the flame retardant effect of the flame retardant copolymer was improved after adding gCDs. The subcooling temperature (ΔTmc) values of MOF material and CEPPA were both higher than those of the DDP flame retardant copolymer after the addition of carbon dots, indicating that the introduction of the carbon-dots material made crystallisation easier. With the increase of carbon dot content, the value first increases and then decreases, indicating that the crystallization is the easiest when the content is 1%, and 1% gCDs+8% DDP has a higher crystallization ability. Pure DDP has the highest mc values, which also shows good spinnability. Also, the cooling rate strongly influences the crystallisation process, with crystallisation being more rapid when the crystallisation rate is higher. Also, the cooling rate strongly influence the crystallisation process, with crystallisation being more rapid when the crystallisation rate is higher.
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Zettergren, Lennart. "INTRACELLULAR PROTEIN CRYSTALLISATION." Acta Pathologica Microbiologica Scandinavica 36, no. 4 (August 14, 2009): 316–22. http://dx.doi.org/10.1111/j.1699-0463.1955.tb04621.x.

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Dissertations / Theses on the topic "Crystallisation"

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Francis, Philip Sydney, and phil francis@rmit edu au. "Crystallisation spectrometer." RMIT University. SET, 2002. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20050617.121435.

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An improved crystallisation spectrometer has been designed, built and tested. It is to be used by others to gain new knowledge about the solidification of matter by study of the crystallisation of hard sphere colloid samples that are an established model for the behaviour of some aspects of atoms. In this crystallisation spectrometer, expanded and collimated green laser light is Bragg scattered from the colloidal crystals as they form, and the diffracted light is focused by a liquid filled hollow glass hemispherical lens onto low cost CCD array detectors that are rotated about the optical axis to average the intensities around the whole Debye-Scherrer cone of scattered light. The temperature of the sample is controlled to +/-0.1„a, and because of the ability to change the refractive index of the sample particles with temperature, this is utilised to control the amount of scattering from the sample Also, this spectrometer uniquely exploits the refractive index match of the colloidal particles, the solvent, the bath liquid, and the glass used for both the sample bottle and the hollow glass hemisphere. A unique facility has been incorporated to permit tumbling of the sample prior to the measurement commencing to shear-melt any pre-existing crystals. This ensures that the sample is completely fluid and is at the correct temperature at the start of the measurement. The instrument is assembled on an optical table and is computer controlled. Results presented show that this new spectrometer with its use of the whole Debye-Scherrer cone of Bragg scattered light and other enhancements gives insight into the crystallisation process more than one order of magnitude of time earlier than previous light scattering experiments, providing new knowledge about the crystallisation process.
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Aumann, Simon. "Nearcritical percolation and crystallisation." Diss., Ludwig-Maximilians-Universität München, 2014. http://nbn-resolving.de/urn:nbn:de:bvb:19-177436.

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This thesis contains results on singularity of nearcritical percolation scaling limits, on a rigidity estimate and on spontaneous rotational symmetry breaking. First it is shown that - on the triangular lattice - the laws of scaling limits of nearcritical percolation exploration paths with different parameters are singular with respect to each other. This generalises a result of Nolin and Werner, using a similar technique. As a corollary, the singularity can even be detected from an infinitesimal initial segment. Moreover, nearcritical scaling limits of exploration paths are mutually singular under scaling maps. Second full scaling limits of planar nearcritical percolation are investigated in the Quad-Crossing-Topology introduced by Schramm and Smirnov. It is shown that two nearcritical scaling limits with different parameters are singular with respect to each other. This result holds for percolation models on rather general lattices, including bond percolation on the square lattice and site percolation on the triangular lattice. Third a rigidity estimate for 1-forms with non-vanishing exterior derivative is proven. It generalises a theorem on geometric rigidity of Friesecke, James and Müller. Finally this estimate is used to prove a kind of spontaneous breaking of rotational symmetry for some models of crystals, which allow almost all kinds of defects, including unbounded defects as well as edge, screw and mixed dislocations, i.e. defects with Burgers vectors.
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Ravenhill, Emma Rosanna. "Crystallisation at functionalised interfaces." Thesis, University of Warwick, 2017. http://wrap.warwick.ac.uk/101542/.

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Within this thesis, a broad range of microscopic and spectroscopic methods are employed to investigate crystallisation processes initiated at novel functionalised interfaces. This approach combines in situ optical microscopy (OM) with several surface sensitive techniques, including atomic force microscopy (AFM), scanning electron microscopy (SEM) and interferometry, with further structural analysis provided via Raman spectroscopy and X-ray diffraction (XRD). This method allows the key mechanistic phenomena to be elucidated to a high level of detail for crystal growth processes with extreme industrial and biological importance. The main focus of the thesis is around a specific industrial problem, concerning the detrimental growth of inorganic crystalline materials within internal combustion engines. Firstly, the deposit structure is revealed by implementing analytical techniques such as SEM, Raman spectroscopy and XRD to characterise real engine deposits. This in depth analysis demonstrates the high abundance of the calcium sulfate polymorphs bassanite (CaSO4⋅0.5H2O) and anhydrite (CaSO4) within the deposit, providing initial insights into this unfavourable growth process. These deposit growth mechanisms are further studied via in situ OM, monitoring calcium sulfate crystallisation at aqueous-organic liquid-liquid interfaces to mimic real life conditions within the engine environment. As well as providing a wealth of knowledge on the deposit formation process, this approach highlights the unique properties liquid-liquid interfaces offer for crystal growth, revealing via Raman spectroscopy and XRD analysis their applicability for synthesising typically unstable materials under low energy, ambient conditions. This industrial problem is further investigated by studying the surface reactivity of the growing calcium sulfate mineral faces via AFM force spectroscopy. This allows interaction forces between the deposit surface and different additive chemistries to be quantitatively determined in an oil-based environment, opening up methods for preventing deposition on engine surfaces. Unexpected, low adhesion values are obtained between polar additive head groups and the polar crystal deposit surface, a consequence of electrostatic repulsion. Thus, this work reveals key aspects related to the structure of charge in organic environments, an area still under much debate. The last chapter of this thesis switches focus to one of the key minerals responsible for engine deposit growth, calcium carbonate. Charged graphite interfaces are implemented to study their effects on the oriented nucleation and polymorphism of this crystal system, in the absence of defects and chemical functionalities. This highlights the significant role electrostatics play in nucleating high energy crystal planes and polymorphs, which is of huge importance for biomineralisation, and scale-prone, charged industrial surfaces. Overall, this thesis elucidates the unexplored properties of two highly relevant functionalised crystal growth interfaces, demonstrating their importance for preventing deposit growth, as well as their diverse application for the synthesis of high energy crystalline materials.
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Helalizadeh, Abbas. "Mixed salt crystallisation fouling." Thesis, University of Surrey, 2002. http://epubs.surrey.ac.uk/844179/.

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The main purpose of this investigation was to study the mechanisms of mixed salt crystallisation fouling on heat transfer surfaces during convective heat transfer and sub-cooled flow boiling conditions. To-date no investigations on the effects of operating parameters on the deposition of mixtures of calcium sulphate and calcium carbonate, which are the most common constituents of scales formed on heat transfer surfaces, have been reported. As part of this research project, a substantial number of experiments were performed to determine the mechanisms controlling deposition. Fluid velocity, heat flux, surface and bulk temperatures, concentration of the solution, ionic strength, pressure and heat transfer surface material were varied systematically. After clarification of the effect of these parameters on the deposition process, the results of these experiments were used to develop a mechanistic model for prediction of fouling resistances, caused by crystallisation of mixed salts, under convective heat transfer and subcooled flow boiling conditions. It was assumed that the deposition process of calcium sulphate and calcium carbonate takes place in two successive events. These events are the combined effects related to transport phenomena and chemical kinetics. The effect of the extra deposition created on the heat transfer surface due to sub-cooled flow boiling was considered by inclusion of an enhancement factor. The newly developed model takes into account the effects of all important parameters on scaling phenomena and also considers the simultaneous precipitation and competition of various minerals in the scale formation process. Model predictions were compared with the measured experimental data when calcium sulphate and calcium carbonate form and deposit on the heat transfer surface simultaneously. While deviations ranging from 6% to 25% between model predictions and measured experimental data can be considered good in the context of such a complex process, fouling morphology is clearly a factor to be considered in more detail. This is particularly problematic in the context of more complex fouling solutions encountered in industry. Furthermore, the crystalline samples were analysed using Scanning Electron Microscopy, X- Ray Diffraction and Ion Chromatography techniques. Fractal analysis performed on Scanning Electron Microscopy photographs of the deposits was used to quantify deposit characteristics by introducing a new quantity called the fractal dimension.
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Emms, S. "Crystallisation of PFA glasses." Master's thesis, University of Cape Town, 1994. http://hdl.handle.net/11427/8485.

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Bibliography: leaves 79-81.
Glasses with various compositions, falling in the CaO-AI20rSi02 and MgO-CaOAI20rSi02 systems were made, using pulverised fuel ash and silica, hydrated lime, kaolin and magnesium carbonate. Titania or ferric oxide and chromia were used as nucleants. Various crystallisation heat treatments were carried out and the nucleation and crystallisation behaviour was studied. A minimum MgO:CaO was found to be necessary for bulk nucleation to occur. The activation energy for viscous flow decreased with increased MgO:CaO ratios. This was accompanied by an increase in the surface crystal growth rates and a decrease in the activation energy for surface crystal growth. Titania also lowered the activation energies for viscous flow and surface crystal growth and caused an increase in the surface crystal growth rates.
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Dincer, Tuna. "Mechanims of lactose crystallisation." Thesis, Curtin University, 2000. http://hdl.handle.net/20.500.11937/1958.

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Lactose is the major carbohydrate in milk. The presence of lactose in whey constitutes a significant pollution problem for dairy factories. At the same time, there is an increasing market for high quality crystalline lactose. The main problem of lactose crystallisation, compared to sucrose, which is also a disaccharide, is that it is very slow, unpredictable and cannot easily be controlled. Compared to sucrose crystallisation, which has been extensively studied, lactose crystallisation lacks the fundamental research to identify the mechanisms of growth and effect of additives. An important difference from most other crystal growth systems is that ([alpha]-lactose hydrate crystals never grow from a pure environment; their growth environment always contains beta lactose. [alpha]-lactose monohydrate crystallises much more slowly because of the presence of [beta]- lactose in all solutions. Although there have been some studies on growth rates and the effect of additives, there has not been any reported work on the fundamentals of lactose crystallisation and the mechanisms that operate on the molecular level. The aim of this thesis is to gain a greater understanding at the fundamental processes, which occur at the molecular level during the crystallisation of lactose, in order to improve control at a macroscopic level.The growth rates of the dominant crystallographic faces have been measured in situ, at three temperatures and over a wide range of supersaturation. The mean growth rates of faces were proportional to the power of between 2.5-3.1 of the relative supersaturation. The rate constants and the activation energies were calculated for four faces. The [alpha]-lactose monohydrate crystals grown in aqueous solutions exhibited growth rate dispersion. Crystals of similar size displayed almost 10 fold difference in the growth rate grown under identical conditions for all the faces. Growth rate dispersion increases with increasing growth rate and supersaturation for all the faces. The variance in the GRD for the (0 10) face is twice the variance of the GRD of the (110) and (100) faces and ten times higher than the (0 11) face at different supersaturations and temperatures. The influence of [beta]-lactose on the morphology of [alpha]-lactose monohydrate crystals has been investigated by crystallising [alpha]-lactose monohydrate from supersaturated DMSO ethanol solutions. The slowness of mutarotation in DMSO allowed preparation of saturated solutions with a fixed, chosen [beta]-lactose content. It was found that [beta]-lactose significantly influences the morphology of [alpha]- lactose monohydrate crystals grown from DMSO solution. At low concentrations of [beta]-lactose, the fastest growing face is the (011) face resulting in long thin prismatic crystals. At higher [beta]-lactose concentrations, the main growth occurs in the b direction and the (020) face becomes the fastest growing face (since the (011) face is blocked by [beta]-lactose), producing pyramid and tomahawk shaped crystals.Molecular modeling was used to calculate morphologies of lactose crystals, thereby defining the surface energies of specific faces, and to calculate the energies of interactions between these faces and [beta]-lactose molecules. It was found that as the replacement energy of [beta]-lactose increased, the likelihood of [beta]-lactose to dock onto faces decreased and therefore the growth rate increased. The attachment energy of a new layer of [alpha]-lactose monohydrate to the faces containing [beta]-lactose was calculated for the (010) and (011) faces. For the (0 10) face, the attachment energy of a new layer was found to be lower than the attachment energy onto a pure lactose surface, meaning slower growth rates when [beta]-lactose was incorporated into the surface. For the (011) face, attachment energy calculations failed to predict the slower growth rates of this face in the presence of [beta]-lactose. AFM investigation of [alpha]-lactose monohydrate crystals produced very useful information about the surface characteristics of the different faces of the [alpha]-lactose monohydrate crystal. The growth of the (010) face of the crystal occurs by the lateral addition of growth layers. Steps are 2 nm high (unit cell height in the b direction) and emanate from double spirals, which usually occurred at the centre of the face. Double spirals rotate clockwise on the (010) face, while the direction of spirals is counterclockwise on the (010) face. A polygonised double spiral, showing anisotropy in the velocity of stepswas observed at the centre of the prism-shaped a-lactose monohydrate crystals grown in the presence of 5 and 10 % [beta]-lactose.The mean spacing of the steps parallel to the (011) face is larger than those parallel to the (100) face, indicating higher growth rates of the (011 )face. The edge free energy of the (011) face is 6.6 times larger than the (100) face in the presence of 5% [beta]-lactose. Increase of [beta]-lactose content from 5% to 10 % decreases the edge free energy of the growth unit on a step parallel to the (011) face by 10 %. Tomahawk-shaped [alpha]-lactose monohydrate crystals produced from aqueous solutions where the [beta]-lactose content of the growth solution is about 60 % have shown clockwise double spirals as the source of unit cell high steps on the (010) face of the crystal. However , the spirals are more circular than polygonised, unlike the prism shaped crystals and the mean step spacing of the (011) face is less than the steps parallel to the (110) face, indicating the growth rate reducing effect of [beta]-lactose on the (011) face. The (100) face of the [alpha]-lactose monohydrate crystal grows by step advancement in relative supersaturations of up to 3.1. Steps are 0.8 nm high and parallel to the c rection. Above this supersaturation, rectangular shaped two-dimensional nuclei, 10 nm high, were observed. The (011) face of the crystal grown at low supersaturations (s= 2.1) displayed a very rough surface with no steps, covered by 4-10nm high and 100-200[micro]m wide formations. Triangular shaped macrosteps were observed when the crystal was grown in solutions with s=3.1. In situ AFM investigation of the (010) face (T = 20[degree]C and s = 1.18) has shown that growth occurs by lateral addition of growth units into steps emanated by double spirals.The growth rate of the (010) face from in situ AFM growth experiments was calculated to be 1.25 gm/min. The growth rate of crystals grown in the in situ optical growth cell under identical conditions was 0.69 pm/min. The difference in growth rates can be attributed to the size difference of seed c stals used. The (010) face of a [alpha]-lactosemonohydrate crystal grown at 22.4 C and s=1.31 displayed triangular-shaped growth fronts parallel to the (011) face. The steps parallel to the (O11) face grow in a triangular shape, and spaces between triangles are filled by growth units until the end of the macrosteps is reached. No such formations were observed on steps parallel to the (110) face. Formation of macrosteps, 4-6 nm high, emanating from another spiral present on the surface was also observed on the (010) face of a crystal grown under these conditions.
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7

Dincer, Tuna. "Mechanims of lactose crystallisation." Curtin University of Technology, School of Applied Chemistry, 2000. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=14562.

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Lactose is the major carbohydrate in milk. The presence of lactose in whey constitutes a significant pollution problem for dairy factories. At the same time, there is an increasing market for high quality crystalline lactose. The main problem of lactose crystallisation, compared to sucrose, which is also a disaccharide, is that it is very slow, unpredictable and cannot easily be controlled. Compared to sucrose crystallisation, which has been extensively studied, lactose crystallisation lacks the fundamental research to identify the mechanisms of growth and effect of additives. An important difference from most other crystal growth systems is that ([alpha]-lactose hydrate crystals never grow from a pure environment; their growth environment always contains beta lactose. [alpha]-lactose monohydrate crystallises much more slowly because of the presence of [beta]- lactose in all solutions. Although there have been some studies on growth rates and the effect of additives, there has not been any reported work on the fundamentals of lactose crystallisation and the mechanisms that operate on the molecular level. The aim of this thesis is to gain a greater understanding at the fundamental processes, which occur at the molecular level during the crystallisation of lactose, in order to improve control at a macroscopic level.
The growth rates of the dominant crystallographic faces have been measured in situ, at three temperatures and over a wide range of supersaturation. The mean growth rates of faces were proportional to the power of between 2.5-3.1 of the relative supersaturation. The rate constants and the activation energies were calculated for four faces. The [alpha]-lactose monohydrate crystals grown in aqueous solutions exhibited growth rate dispersion. Crystals of similar size displayed almost 10 fold difference in the growth rate grown under identical conditions for all the faces. Growth rate dispersion increases with increasing growth rate and supersaturation for all the faces. The variance in the GRD for the (0 10) face is twice the variance of the GRD of the (110) and (100) faces and ten times higher than the (0 11) face at different supersaturations and temperatures. The influence of [beta]-lactose on the morphology of [alpha]-lactose monohydrate crystals has been investigated by crystallising [alpha]-lactose monohydrate from supersaturated DMSO ethanol solutions. The slowness of mutarotation in DMSO allowed preparation of saturated solutions with a fixed, chosen [beta]-lactose content. It was found that [beta]-lactose significantly influences the morphology of [alpha]- lactose monohydrate crystals grown from DMSO solution. At low concentrations of [beta]-lactose, the fastest growing face is the (011) face resulting in long thin prismatic crystals. At higher [beta]-lactose concentrations, the main growth occurs in the b direction and the (020) face becomes the fastest growing face (since the (011) face is blocked by [beta]-lactose), producing pyramid and tomahawk shaped crystals.
Molecular modeling was used to calculate morphologies of lactose crystals, thereby defining the surface energies of specific faces, and to calculate the energies of interactions between these faces and [beta]-lactose molecules. It was found that as the replacement energy of [beta]-lactose increased, the likelihood of [beta]-lactose to dock onto faces decreased and therefore the growth rate increased. The attachment energy of a new layer of [alpha]-lactose monohydrate to the faces containing [beta]-lactose was calculated for the (010) and (011) faces. For the (0 10) face, the attachment energy of a new layer was found to be lower than the attachment energy onto a pure lactose surface, meaning slower growth rates when [beta]-lactose was incorporated into the surface. For the (011) face, attachment energy calculations failed to predict the slower growth rates of this face in the presence of [beta]-lactose. AFM investigation of [alpha]-lactose monohydrate crystals produced very useful information about the surface characteristics of the different faces of the [alpha]-lactose monohydrate crystal. The growth of the (010) face of the crystal occurs by the lateral addition of growth layers. Steps are 2 nm high (unit cell height in the b direction) and emanate from double spirals, which usually occurred at the centre of the face. Double spirals rotate clockwise on the (010) face, while the direction of spirals is counterclockwise on the (010) face. A polygonised double spiral, showing anisotropy in the velocity of stepswas observed at the centre of the prism-shaped a-lactose monohydrate crystals grown in the presence of 5 and 10 % [beta]-lactose.
The mean spacing of the steps parallel to the (011) face is larger than those parallel to the (100) face, indicating higher growth rates of the (011 )face. The edge free energy of the (011) face is 6.6 times larger than the (100) face in the presence of 5% [beta]-lactose. Increase of [beta]-lactose content from 5% to 10 % decreases the edge free energy of the growth unit on a step parallel to the (011) face by 10 %. Tomahawk-shaped [alpha]-lactose monohydrate crystals produced from aqueous solutions where the [beta]-lactose content of the growth solution is about 60 % have shown clockwise double spirals as the source of unit cell high steps on the (010) face of the crystal. However , the spirals are more circular than polygonised, unlike the prism shaped crystals and the mean step spacing of the (011) face is less than the steps parallel to the (110) face, indicating the growth rate reducing effect of [beta]-lactose on the (011) face. The (100) face of the [alpha]-lactose monohydrate crystal grows by step advancement in relative supersaturations of up to 3.1. Steps are 0.8 nm high and parallel to the c rection. Above this supersaturation, rectangular shaped two-dimensional nuclei, 10 nm high, were observed. The (011) face of the crystal grown at low supersaturations (s= 2.1) displayed a very rough surface with no steps, covered by 4-10nm high and 100-200[micro]m wide formations. Triangular shaped macrosteps were observed when the crystal was grown in solutions with s=3.1. In situ AFM investigation of the (010) face (T = 20[degree]C and s = 1.18) has shown that growth occurs by lateral addition of growth units into steps emanated by double spirals.
The growth rate of the (010) face from in situ AFM growth experiments was calculated to be 1.25 gm/min. The growth rate of crystals grown in the in situ optical growth cell under identical conditions was 0.69 pm/min. The difference in growth rates can be attributed to the size difference of seed c stals used. The (010) face of a [alpha]-lactosemonohydrate crystal grown at 22.4 C and s=1.31 displayed triangular-shaped growth fronts parallel to the (011) face. The steps parallel to the (O11) face grow in a triangular shape, and spaces between triangles are filled by growth units until the end of the macrosteps is reached. No such formations were observed on steps parallel to the (110) face. Formation of macrosteps, 4-6 nm high, emanating from another spiral present on the surface was also observed on the (010) face of a crystal grown under these conditions.
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Le, Corre Kristell S. "Understanding struvite crystallisation and recovery." Thesis, Cranfield University, 2006. http://dspace.lib.cranfield.ac.uk/handle/1826/1434.

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Struvite crystallisation from wastewater effluents is seen as an alternative to traditional biological and chemical phosphorus removal processes used widely in the wastewater treatment industry. It presents the advantage of not only removing phosphorus but also generating a compound that could be reused as a fertiliser. However the application of struvite crystallisation processes at full scale is not widespread due to the unknown economical value of the process and the product, the need of pH control, the necessity of long operational times to ensure quality of the product and the formation of crystal fines. Preliminary crystallisation experiments were carried out at laboratory scale to provide a better understanding of nucleation and growth processes, and identify how basic parameters such as pH, mixing energy, water chemistry or presence of foreign ions affected struvite crystallisation. Particular attention was paid to the quality (i.e. size, shape and purity) of the crystal formed. The results revealed that the presence of calcium ions in solution could alter struvite purity and even inhibit its formation. pH was also identified as a parameter of major impact on struvite crystal quality. Indeed, pH could either influence struvite purity or affect size of crystals formed. Further investigations in a purposely built reactor also revealed that if struvite crystallisation is relatively simple to achieve, the control of struvite quality and more particularly crystal size is complex. Results at pilot scale showed that reactor operation and struvite surface charge could be a limitation to its agglomerative properties, hence to the formation of larger crystals. To optimise struvite crystallisation and limit the problem of fines formation the present study has investigated two possible solutions: struvite fines recovery by coagulation or struvite crystallisation on seed materials. Struvite coagulation proved to be an efficient solution to remove and recover struvite fines rapidly through floc formation. Of the coagulant tested, polyDADMAC was the most effective resulting in the formation of flocs 10 times bigger than the initial size of crystals. With regards to crystallisation on seed materials, the results revealed that success of struvite attachment onto seeds in short contact times was only efficient when mixing energy in the reactor was limited. In that sense, the submersion of a metallic system in the reactor allowed excellent phosphorus removal and rapid struvite recovery in only 2 hours of operation.
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Adler, Ayal. "Crystallisation : for a large orchestra." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=85219.

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This essay presents an analysis of Crystallisation, a composition for a large orchestra. The work consists of a single movement, with a duration of approximately 15 minutes.
The analysis focuses mainly on formal structure, pitch organization, texture and rhythm. Some of the main topics are: large-scale form and subdivisions of each section, thematic interrelations of the sections, central pitches, pitch collections, chord structure and interrelations between texture and rhythm.
Throughout the course of the work, the music closely follows an overall process of searching for a valid structure and "core". In realizing this process the music takes on a variety of devices, among them: various kinds of symmetry within texture and form; thematic relations between separate sections through variants and material transformation; a coherent pitch organization which contains structural pitches, symmetrical collections and three main groups of chords; a complex and carefully structured rhythmic organization.
The concluding section of this essay compares between some of the properties of a crystal and the structure of various parts in Crystallisation.
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Crispin, Matthew D. M. "Manipulation and crystallisation of glycoproteins." Thesis, University of Oxford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426374.

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Books on the topic "Crystallisation"

1

Mullin, J. W. Crystallisation. 3rd ed. Oxford: Butterworths, 1993.

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Ricard, F. D. Protein crystallisation using novel surfactants. Manchester: UMIST, 1998.

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Crystallisation of caste in frontier Bengal. New Delhi: Classical Pub. Co., 2003.

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Shields, E. The solubility and crystallisation of sodium cromoglycate. Manchester: UMIST, 1990.

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Withey, Ruth Elizabeth. The crystallisation behaviour of poly(hydroxybutyrate-co-valerate). Birmingham: University of Birmingham, 1998.

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Taylor, Alan. The Chemical syntheis and crystallisation sequence of mullite. [s.l.]: typescript, 1992.

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Lewis, B. The use of semi-open refrigeration cycle for crystallisation from aqueous solution. Luxembourg: Commission of the European Communities, 1991.

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Joyner, Louise. The geochemistry and crystallisation history of pyroxenes from hypabassal basic igneous rocks. Portsmouth: University of Portsmouth, Dept. of Geology, 1993.

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Elliot, Paul. Mixing and crystallisation conditions in supported nickel catalyst preparation and their influence on catalyst performance. Birmingham: University of Birmingham, 1990.

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Lafferty, Ian. The effect of crystallisation variables on the powder characteristics, mechanical properties and compression behaviour of dextrose. Leicester: De Montfort University, 1998.

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Book chapters on the topic "Crystallisation"

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Ageorges, C., and L. Ye. "Crystallisation Kinetics." In Engineering Materials and Processes, 135–60. London: Springer London, 2002. http://dx.doi.org/10.1007/978-1-4471-0171-0_5.

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Hofmann, Guenter. "Vacuum Crystallisation." In Vacuum Technology in the Chemical Industry, 189–210. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2014. http://dx.doi.org/10.1002/9783527653898.ch9.

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Vaccari, G., and G. Mantovani. "Sucrose crystallisation." In Sucrose, 33–74. Boston, MA: Springer US, 1995. http://dx.doi.org/10.1007/978-1-4615-2676-6_3.

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Brown, Cameron, Thomas McGlone, and Alastair Florence. "Continuous Crystallisation." In Continuous Manufacturing of Pharmaceuticals, 169–226. Chichester, UK: John Wiley & Sons, Ltd, 2017. http://dx.doi.org/10.1002/9781119001348.ch5.

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Camacho Corzo, Diana M., Cai Y. Ma, Vasuki Ramachandran, Tariq Mahmud, and Kevin J. Roberts. "Crystallisation Route Map." In Engineering Crystallography: From Molecule to Crystal to Functional Form, 179–213. Dordrecht: Springer Netherlands, 2017. http://dx.doi.org/10.1007/978-94-024-1117-1_11.

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Parambil, Jose V., and Jerry Y. Y. Heng. "Seeding in Crystallisation." In Engineering Crystallography: From Molecule to Crystal to Functional Form, 235–45. Dordrecht: Springer Netherlands, 2017. http://dx.doi.org/10.1007/978-94-024-1117-1_13.

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Timms, R. E. "Crystallisation of fats." In Developments in Oils and Fats, 204–23. Boston, MA: Springer US, 1995. http://dx.doi.org/10.1007/978-1-4615-2183-9_8.

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Bott, T. R. "Crystallisation of Organic Materials." In Fouling Science and Technology, 275–80. Dordrecht: Springer Netherlands, 1988. http://dx.doi.org/10.1007/978-94-009-2813-8_20.

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Talbot, G. "Fat eutectics and crystallisation." In Physico-Chemical Aspects of Food Processing, 142–66. Boston, MA: Springer US, 1995. http://dx.doi.org/10.1007/978-1-4613-1227-7_7.

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Hills, Alice. "Crystallisation of British Policy." In Britain and the Occupation of Austria, 1943–45, 32–44. London: Palgrave Macmillan UK, 2000. http://dx.doi.org/10.1057/9781403919502_3.

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Conference papers on the topic "Crystallisation"

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Francois, N., M. Saadatfar, M. Hanifpour, R. Cruikshank, and A. Sheppard. "Crystallisation in a granular material." In POWDERS AND GRAINS 2013: Proceedings of the 7th International Conference on Micromechanics of Granular Media. AIP, 2013. http://dx.doi.org/10.1063/1.4811944.

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Einhaus, R., J. Kraiem, F. Lissalde, S. Dubois, N. Enjalbert, and R. Monna. "Crystallisation of purified metallurgical silicon." In 2008 33rd IEEE Photovolatic Specialists Conference (PVSC). IEEE, 2008. http://dx.doi.org/10.1109/pvsc.2008.4922521.

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Lifran, E., L. Vu, R. Durham, J. Hourigan, and R. Sleigh. "Crystallisation Kinetics of Ultra Pure Lactose." In 13th World Congress of Food Science & Technology. Les Ulis, France: EDP Sciences, 2006. http://dx.doi.org/10.1051/iufost:20060034.

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Sibik, Juraj, Nicholas Y. Tan, Denis Arslanov, Wim van der Zande, Britta Redlich, and J. Axel Zeitler. "Terahertz-induced crystallisation of amorphous systems." In 2015 40th International Conference on Infrared, Millimeter, and Terahertz waves (IRMMW-THz). IEEE, 2015. http://dx.doi.org/10.1109/irmmw-thz.2015.7327556.

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Lecampion, Brice. "Crystallisation Preferred Orientation in Porous Media." In First Southern Hemisphere International Rock Mechanics Symposium. Australian Centre for Geomechanics, Perth, 2008. http://dx.doi.org/10.36487/acg_repo/808_96.

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Healy, N., S. Mailis, T. D. Day, P. J. A. Sazio, J. V. Badding, and A. C. Peacock. "Laser crystallisation of semiconductor core optical fibres." In 2013 Conference on Lasers & Electro-Optics Europe & International Quantum Electronics Conference CLEO EUROPE/IQEC. IEEE, 2013. http://dx.doi.org/10.1109/cleoe-iqec.2013.6801574.

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Green, C. D., and A. S. Vaughan. "Morphology and crystallisation kinetics of polyethylene / montmorillonite nanocomposites." In 2007 Annual Report - Conference on Electrical Insulation and Dielectric Phenomena. IEEE, 2007. http://dx.doi.org/10.1109/ceidp.2007.4451507.

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Green, C. D., and A. S. Vaughan. "Morphology and Crystallisation Kinetics of Polyethylene / Montmorillonite Nanocomposites." In 2007 IEEE International Conference on Solid Dielectrics. IEEE, 2007. http://dx.doi.org/10.1109/icsd.2007.4290829.

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Fernández, Julián R. "Crystallisation and Local Order in Glass-Forming Binary Mixtures." In SLOW DYNAMICS IN COMPLEX SYSTEMS: 3rd International Symposium on Slow Dynamics in Complex Systems. AIP, 2004. http://dx.doi.org/10.1063/1.1764215.

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Healy, N., A. C. Peacock, J. R. Sparks, N. F. Baril, P. J. A. Sazio, and J. V. Badding. "Simultaneous tapering and crystallisation of silicon core optical fibres." In 11th European Quantum Electronics Conference (CLEO/EQEC). IEEE, 2009. http://dx.doi.org/10.1109/cleoe-eqec.2009.5196514.

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