Статті в журналах з теми "Anomalous viscosity liquids"

The work is devoted to the peculiarities of free-convective flow of liquids with viscosity temperature anomaly (the presence of extremes on the viscosity curve). Examples of such liquids are polymer solutions, metal melts, well-purified liquid sulfur, and other fluids. The mechanism of the anomalous viscosity behavior of such liquids (in the case of polymers) can be explained by polymerization and depolymerization reactions. At a certain temperature interval, the molecules of a substance interlock, forming long chains and, as a result, increasing the viscosity, then when the upper limit polymerization temperature is reached, the reaction begins that is reverse to the polymerization, which proceeds according to the chain mechanism and results in the sequential cleavage of molecules from the chain and leads to a decrease in viscosity . The features of behavior of such environments are currently not well understood and require increased attention to experimental and theoretical studies, especially now, mainly due to the intensive development of computer technologies and numerical modeling. Based on computational experiments on the process of free convection of a liquid with a Gaussian dependence of viscosity on temperature, the possibility of the existence of isolated regimes of convection of a liquid in a square cell heated from the side is shown. It was assumed that the viscosity function has one extremum and is unambiguously described by two parameters: the ratio of the highest to the lowest viscosity at a given temperature range and the degree of fullness of a given temperature range. As a mathematical model, a system of equations was used in the Oberbeck–Boussinesq approximation. For the numerical solution of the system of equations, the control volume method with the SIMPLE procedure is modified and implemented.

It is well known that an increased viscosity slows down fluid dynamics. Here we show that this intuitive rule is not general and can fail for liquids flowing in confined liquid-repellent systems. A gravity-driven, highly viscous glycerol droplet inside a sealed superhydrophobic capillary is moving more than 10 times faster than a water droplet with three-orders-of-magnitude lower viscosity. Using tracer particles, we show that the low-viscosity droplets are rapidly rotating internally, with flow velocities greatly exceeding the center-of-mass velocity. This is in stark contrast to the faster moving high-viscosity droplets with nearly vanishing internal flows. The anomalous viscosity-enhanced flow is caused by a viscosity-suppressed deformation of the droplet-air interface and a hydro- and aerodynamic coupling between the droplet and the air trapped within the micro/nanostructures (plastron). Our work demonstrates the unexpected role of the plastron in controlling fluid flow beyond the mere reduction in contact area and friction.

The current stage in the development of agricultural production in livestock is characterized by the extensive use of pipeline transport to move the forage masses, which are related to non-Newtonian fluids. Production experience and scientific work on the study of hydrotransport systems showed that this method of transportation is the most economical and promising, it has high reliability of structural elements, improves sanitary and hygienic working conditions and makes it possible to fully automate the transportation process. The complex nature of the transportation of mixtures has not allowed to create a unified theory of hydrodynamic calculation of their parameters to date, therefore, various models are used for theoretical investigation of the nature of motion. To select a particular model, it is always important to correctly classify viscous semiliquid media with respect to hydrodynamics. Therefore, the article did not set out the specific goal of choosing a method for studying non-Newtonian systems, but solved the problem of their classification by known defining characteristics. The proposed classification does not pretend to be exhaustive in terms of the physical and chemical nature of the fluid, especially their combinations, but it covers almost all the anomalous phenomena that occur in the fluid during its transportation and helps to select a quantitative method for calculating the transporting fluid. The classification of non-Newtonian fluids with respect to their hydromechanics is based on the dependence of the shear stress on the shear gradient. For this dependence, each type of liquid is considered. The developed classification scheme further promotes a more complete account of the rheological properties of high-viscosity liquids during their transportation through pipes and facilitates the development of quantitative calculation methods.

Study of the melting process in rapid melting of spin-polarized 3He reveals that the liquid's magnetic susceptibility is enhanced at moderate temperatures (above 30 mK) and moderate polarization (20–40%) but declines at higher polarization. The first transport measurement on the enhanced polarized liquid shows anomalous behavior. Together, these measurements favor a microscopic model in which, at moderate temperatures and as a function of polarization, the liquid approaches but does not achieve a new phase.

We investigated the kinematic viscosity and electrical resistivity of the multicomponent Fe74Cu1Nb1.5Mo1.5B8.5Si13.5 melt during three heating–cooling cycles. The temperature dependence of kinematic viscosity and electrical resistivity have the anomalous zones in the same temperature range and they are associated with the liquid–liquid structure transition (LLST). The anomalies were explained by changes in the activation energy and the cluster size. As the cluster size decreases, the activation energy decreases, but the viscosity and electrical resistance increase. LLST begins with the cluster dissolution, and as a result, the Arrhenius plot becomes nonlinear in the transition temperature range. After three cycles of heating–cooling, the temperature dependences of the kinematic viscosity and electrical resistance did not qualitatively change, and this allows us to conclude that LLST is thermoreversible. With an increase in the number of thermal cycles, the activation energy of viscous flow decreases, as well as the onset temperature and temperature range of LLST.

The flow of an impinging non-Newtonian jet onto a solid flat plate is examined theoretically in this study. Similarity solutions are sought for both shear-thinning and shear-thickening fluids of the power-law type. The jet is assumed to spread out in a thin layer bounded by a hydraulic jump. In addition to the stagnation-flow region, the flow domain is divided into three main regions: a developing boundary layer, fully viscous boundary layer and hydraulic jump. The anomalous behaviour of power-law fluids at small shear rate is remedied by seeking a two-layer solution in each domain. Such anomalies include the singularity of viscosity for shear-thinning fluids, and the vanishing of viscosity as well the overshoot in velocity for shear-thickening fluids. Although the rate of shear-thinning appears to affect significantly the film profile and velocity, only the overall viscosity influences the position of the hydraulic jump.

The anomalous decrease of the viscosity of water with applied pressure has been known for over a century. It occurs concurrently with major structural changes: The second coordination shell around a molecule collapses onto the first shell. Viscosity is thus a macroscopic witness of the progressive breaking of the tetrahedral hydrogen bond network that makes water so peculiar. At low temperature, water at ambient pressure becomes more tetrahedral and the effect of pressure becomes stronger. However, surprisingly, no data are available for the viscosity of supercooled water under pressure, in which dramatic anomalies are expected based on interpolation between ambient pressure data for supercooled water and high pressure data for stable water. Here we report measurements with a time-of-flight viscometer down to 244K and up to 300MPa, revealing a reduction of viscosity by pressure by as much as 42%. Inspired by a previous attempt [Tanaka H (2000) J Chem Phys 112:799–809], we show that a remarkably simple extension of a two-state model [Holten V, Sengers JV, Anisimov MA (2014) J Phys Chem Ref Data 43:043101], initially developed to reproduce thermodynamic properties, is able to accurately describe dynamic properties (viscosity, self-diffusion coefficient, and rotational correlation time) as well. Our results support the idea that water is a mixture of a high density, “fragile” liquid, and a low density, “strong” liquid, the varying proportion of which explains the anomalies and fragile-to-strong crossover in water.

The mathematical model is developed and the numerical research of a filtration flow features of liquid with model nonmonotonic dependence of viscosity on temperature is conducted. Existence of the ”viscous barrier“ defining character of a filtration flow of anomalous thermoviscous liquid in the porous medium is established. Characteristic pictures of the steady distribution of viscosity and temperature in layered non-uniform formation are constructed. It is established that formation flow rate depends on a maximum of viscosity coefficient and pressure difference essentially.

A four-probe dc method for measuring the electrical resistivity of liquid quasicrystal Al63Cu25Fe12 was investigated in this article and found out that the resistivity of the melt temperature negative factors. Resistivity in alloy melting temperature near the lower interval occurred in phase I and λ, but is not happen to shift in β phase. That would not cause phase change of electronic transport, may be held without fracture, and held the bond length is changed. The viscosity of liquid quasicrystal Al63Cu25Fe12 was tested by using torsional oscillation viscosity measurement. Anomalous change at the temperature of (1401-1473)K occurred from the viscosity-temperature cures, some liquid-liquid change has taken place at this temperature.

The work investigated the temperature dependences of the kinematic viscosity for multicomponent melts of nanocrystalline soft magnetic alloys. It is shown that there is a linear relationship between the reduced activation energy of viscous flow Ea·(RT)−1 and the pre-exponential factor ν0. This ratio is universal for all quantities, the temperature dependence of which is expressed by the Arrhenius equation. It is shown that the activation energy of a viscous flow is linearly related to the cluster size on a natural logarithmic scale, and the melt viscosity increases with decreasing cluster size. The change in the Arrhenius plot in the anomalous zone on the temperature dependence of viscosity can be interpreted as a liquid–liquid structure transition, which begins with the disintegration of clusters and ends with the formation of a new cluster structure.

The steady flow of anomalous thermoviscous liquid between the coaxial cylinders is considered. The inner cylinder rotates at a constant angular velocity while the outer cylinder is at rest. On the basis of numerical experiment various flow regimes depending on the parameter of viscosity temperature dependence are found.

In work the single-phase filtration of anomalous thermoviscous liquid on an example of thermoreversible polymer gel, named МЕТКА, is simulated numerically. Features of a filtration liquid flow at her injection into porous medium are investigated. Characteristic distribution pictures of fields of temperature, viscosity and velocity vector components are constructed when using first-type and third-type boundary conditions.

Electrorheological (ER) effects in the nematic (Ne), the smectic A (SmA) and the isotropic (Is) phases of octyloxy cyanobiphenyl (8OCB) are studied. When an electric field is applied, a large decrease of the viscosity is observed in the Sm A phase, while in the Ne phase an increase of the viscosity is recognized with an anomalous ER effect near the SmA-Ne phase transition. These behaviors are suggested to be general properties of the liquid crystal exhibiting the phase sequence of SmA-Ne-Is.

Foamed metal is a kind of porous material with pores in the metal matrix. One of the possible process routes is to blow gas bubbles into liquid metals. However, many metallic foams produced by this foaming method have coarse and irregular cell structures. The industrial aim is to fabricate foams with more uniform structure and cell size. It is important to understand the mechanisms and factors controlling. The rheological characteristics are the most important factors in the metal foam manufacturing. Thus this study investigated the bubble behavior of the molten metal and its two most important two parameters: surface tension and liquid viscosity. The surface tension (by the ring method) and the viscosity (by the rotation method) of Mg-Al alloy (AZ91, AM60) have been measured under pure Ar and SF6 + CO2 atmosphere. The results show that the surface tension and the viscosity of these alloys decrease with increasing temperature. The addition of Ca and SiC to Mg alloys decreases the surface tension and increases the viscosity. This anomalous behavior is related with the preferential adsorption of high activity elements on the surface.

In this work, the physical properties of Fe48Cr15Mo14C15B6Y2 alloy in liquid state at high temperature are studied. It was observed that the basic physical characteristics of the alloy, such as viscosity, electrical resistivity, and density, decrease with an increase of the temperature to 1700 °C. An abnormal increasing rate of viscosity for Fe48Cr15Mo14C15B6Y2 alloy in the temperature range from 1360 to 1550 °C was noted. The measurement of the electrical resistivity and density did not reveal any anomalies in the same temperature range.

The liquid structure of two lead-free solder Molten alloys, Sn-0.5Cu and Sn-1.8Cu (wt.%), has been examined using X-ray diffraction method. The main peak for liquid structure of Sn-0.5Cu is similar to that of pure Sn. A pre-peak has been found in the low Q part on the structure factor S(Q) of Sn-1.8Cu tested under 320°C, but it disappeared finally when the testing temperature reached 350°C. The both viscosity was measured using a torsional oscillation viscometer. It was found that the anomalous variations of viscosity had a direct relation with the transition of the liquid structure, which is consonant with the results of high temperature X-ray diffraction. The microstructure of the solder matrixes as well as interfacial reaction between liquid solders and Cu substrates was also studied. The results show that particle-like Cu6Sn5 intermetallic compounds (IMCs) emerge in Sn-1.8Cu solder matrix. The IMC layer at Sn-1.8Cu/Cu joint is thicker than that at Sn-0.5Cu/Cu interface. The correlative effect of liquid structure on phase evolution in the solder joints is analyzed.

Temperature dependences of liquid alloys contain non-monotonic fragments in the form of excesses and breaks. The paper analyzes the dependences of oscillations’ attenuation ratio upon temperature. The qualitative and quantitative estimation of anomalies on melt properties’ dependences upon temperature is made, for example, values of viscosity. The proposed approach allows analyzing properties of the melt and developing technological recommendations for production of materials possessing high characteristics.

In the paper the results of numerical modeling of the flow of an incompressible fluid with a non-monotonic dependence of the viscosity on the temperature in a channel are presented. On the channel’s walls the heat exchange is specified that are written mathematically in the form of the boundary conditions of the third kind on the basis of the Newton– Richman convective heat exchange law. The regimes of flow stabilization in the channel depending on the Nusselt numbers have been studied. Four different types of unsteady processes are discovered and it has been shown that they are determined by the different heat exchange intensity.

Thermodynamic and acoustical study of cholesteric liquid crystal (CLC) was carried out near phase transition temperatures using an ultrasonic interferometer. The study of ultrasonic waves and related thermo-acoustical parameters provides information in understanding the nature of molecular interactions associated with liquid crystals. A statistical mechanical approach is used to calculate the viscosity of samples. The characteristic textures and phase transition temperatures are obtained with Polarizing Microscopy (POM). Fabry Perot scattering studies (FPSS) are used to ascertain the phase transition temperatures of CLC. The thermo-acoustical parameters have been calculated using experimental data with well-known formulae. The acoustical parameters show variation with temperature as well as with concentration of CLC. Anomalous behavior of these parameters is noticed at the clearing temperature of CLC. The variation of the parameters is explained in terms of solute-solvent molecular interactions in the solution. The molecular behavior, structural changes, and intermolecular interactions between CLC and solvent are discussed in detail.

This paper presents a deliberately designed elastohydrodynamical lubrication (EHL) experiment for the study of the individual effect of the limiting shear stress and wall slippage. Very slow entrainment speeds were employed to avoid influential shear heating and oils of high viscosities were chosen to ensure that the conjunction was under typical EHL. An anomalous EHL film, characterized by a dimple at the inlet region, was obtained. Literature revealed that this inlet dimple was reported in some numerical studies taking into consideration the limiting-shear-stress characteristics of the lubricant and wall slippage. It was found that even under the same kinematic conditions, different types of film shape would be generated by simple disc sliding and simple ball sliding. Simple disc sliding produces an inlet dimple with a comparatively thick inlet film thickness, which droops rapidly toward the outlet region. For simple ball sliding, there is also an inlet dimple but the central film thickness is rather uniform. However, by prerunning the conjunction at a zero entrainment velocity (at the same linear speeds but in opposite directions) before the sliding experiment, the slope of the central film of simple disc sliding becomes smaller. It is probably due to the modification of solid-liquid interface, i.e., the slippage level, by the highly pressurized and stressed prerunning conditions. With a prescribed prerunning, which can produce very similar films at simple disc sliding and simple ball sliding, variation of film thickness was studied and it was found that the inlet dimple film has obvious dependence on entrainment speeds, but was not sensitive to loads. The present experimental results can be considered as direct evidence for those numerical findings of the inlet dimple. Tentatively, an effective viscosity wedge is proposed to account for the formation of the inlet dimple.

We study the effects of Ag addition on thermal stability and thermophysical properties of Ti-Zr-Ni icosahedral quasicrystals. The Ag addition results in increasing the coherence length and thermal stability of the icosahedral phase (i-phase) of the as-cast Ti35.2Zr43.8Ni21 alloy, which are maximized at around 4 at.% Ag addition. Differential scanning calorimetry (DSC) and electrostatic levitation (ESL) experiments reveal that the addition suppresses the i-phase decomposition on heating and cooling. We find that considerable amount of the i-phase remains in the samples processed by radiational cooling in ESL as the Ag concentration increases. These results demonstrate that Ag addition stabilizes the i-phase of the Ti35.2Zr43.8Ni21 alloy. No anomalous effect of Ag addition is found on density and viscosity of the Ti35.2Zr43.8Ni21 liquid.

В различных технических приложениях применяются рабочие среды типа суспензий, которые при достаточно высокой концентрации частиц твердой фазы демонстрируют аномалии вязкости. Существо этих аномалий заключается в том, что при приближении скорости сдвига к некоторому пороговому значению наблюдается явление резкого возрастания вязкости жидкости. При этом в соответствующих зонах течения рабочая среда начинает вести себя подобно твердому телу. Механическое поведение такой рабочей среды может быть описано в рамках реологической модели вязкопластической жидкости, которая позволяет учитывать проявление эффекта“упрочнения” или “отвердевания”. Рассмотрена методика определения параметров такой реологической модели на основе обработки экспериментальных данных зависимости касательного напряжения от скорости сдвига. Предложен алгоритм для реализации этой методики. In various technical applications, working media such as suspensions are used, which, at a sufficiently high concentration of solid phase particles, demonstrate viscosity anomalies. The essence of these anomalies lies in the fact that when the shear rate approaches a certain threshold value, the phenomenon of a sharp increase in the viscosity of the liquid is observed. At the same time, in the corresponding flow zones, the working medium begins to behave like a solid. The mechanical behavior of such a working medium can be described within the framework of a rheological model of a viscoplastic fluid, which allows for the manifestation of the effect of “hardening” or “solidification”. The method of determining the parameters of such a rheological model based on the processing of experimental data on the dependence of the shear stress on the shear rate is considered. An algorithm for the implementation of this technique is proposed

Abstract It is known that the dynamic viscosity coefficient of slag – with an increased titanium compounds content in the reducing conditions of the blast furnace - may rapidly change. The products of the reduction reaction, precipitation and separation of titanium compounds are responsible for the thickening effect of the slag and the problems of permeability of blast furnace, causing anomalies in the dipping zone. The presence of solid components (particles) in the melts determines the rheological character of the entire system. Identifying the rheological character of semi-solid slag systems provides opportunities for the development of mathematical modeling of liquid phase flows in a dripping zone of the blast furnace, allowing e.g to indentify the unstable parts of a metallurgical aggregate. Author have performed study of synthetic aluminosilicates slag concentration of TiO2 in the range up to 30%, systems were doped solids TiN also, it was made in order to assess the impact of the type forming areas/units of the SRO nature on the rheological identification mentioned systems. The high-temp rheometric measurements were performed at temperatures in the range between 1310-1490°C. The obtained results made it possible to carry out the rheological characteristics of analyzed liquid and semi-solid slag systems.

Abstract The question of ‘what is the structure of water?’ has been regarded as one of the major scientific conundrums in condensed-matter physics due to the complex phase behavior and condensed structure of supercooled water. Great effort has been made so far using both theoretical analysis based on various mathematical models and computer simulations such as molecular dynamics and first-principle. However, these theoretical and simulation studies often do not have strong evidences of condensed-matter physics to support. In this study, a cooperative domain model is formulated to describe the dynamic phase transition of supercooled water between supercooled water and amorphous ice, both of which are composed of low- and high-density liquid water. Free volume theory is initially employed to identify the working principle of dynamic phase transition and its connection to glass transition in the supercooled water. Then a cooperative two-state model is developed to characterize the dynamic anomalies of supercooled water, including density, viscosity and self-diffusion coefficient. Finally, the proposed model is verified using the experimental results reported in literature.

The applying of burden materials containing titanium compounds in the blast furnace process and the processes of forming titanium carbides and nitrides has a directly impact on the physical and chemical properties of slag and pig iron. Thereby affecting the course of the process, its efficiency and economy. It is known that the dynamic viscosity coefficient of slag – with an increased titanium compounds content in the reducing conditions of the blast furnace - may rapidly change. The products of the reduction reaction, precipitation and separation of titanium compounds are responsible for the thickening effect of the slag and the problems of permeability of blast furnace, causing anomalies in the functioning of the unit. The presence of solid components (particles) in the melts determines the rheological character of the entire system. Authors have performed a rheological study of synthetic furnace slag concentration of TiO2 in the range of 6% to 30%. The measurements were performed at temperatures in the range between 1310-1490oC. The obtained results made it possible to carry out the rheological characteristics of analyzed liquid and semi-solid slag systems and draw of flow curves. Identifying the rheological character of semi-solid slag systems provides opportunities for the development of mathematical modeling of liquid phase flows in a dripping zone of the blast furnace, allowing e.g to indentify the unstable parts of a metallurgical aggregate.

800x600 The applying of burden materials containing titanium compounds in the blast furnace process and the processes of forming titanium carbides and nitrides has a directly impact on the physical and chemical properties of slag and pig iron. Thereby affecting the course of the process, its efficiency and economy. It is known that the dynamic viscosity coefficient of slag – with an increased titanium compounds content in the reducing conditions of the blast furnace - may rapidly change. The products of the reduction reaction, precipitation and separation of titanium compounds are responsible for the thickening effect of the slag and the problems of permeability of blast furnace, causing anomalies in the functioning of the unit. The presence of solid components (particles) in the melts determines the rheological character of the entire system.Authors have performed a rheological study of synthetic furnace slag concentration of TiO2 in the range of 6% to 30%. The measurements were performed at temperatures in the range between 1310-1490oC. The obtained results made it possible to analyze the rheological characteristics of liquid and semi-solid slag systems and produce flow curves. Identifying the rheological character of semi-solid slag systems provides opportunities for the development of a mathematical model of liquid phase flow in a dripping zone of the blast furnace, allowing for example to indentify the unstable parts of a metallurgical aggregate. Normal 0 21 false false false PL X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:Standardowy; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman","serif";}

The random first order transition theory (RFOT) describing the transition from a supercooled liquid to an ideal glass has been actively developed over the last twenty years. This theory is formulated in a way that allows a description of the transition from the initial equilibrium state to the final metastable state without considering any kinetic processes. The RFOT and its applications for real molecular systems (multicomponent liquids with various intermolecular potentials, gel systems, etc.) are widely represented in English-language sources. However, these studies are practically not described in any Russian sources. This paper presents an overview of the studies carried out in this field. REFERENCES 1. Sanditov D. S., Ojovan M. I. Relaxation aspectsof the liquid—glass transition. Uspekhi FizicheskihNauk. 2019;189(2): 113–133. DOI: https://doi.org/10.3367/ufnr.2018.04.0383192. Tsydypov Sh. B., Parfenov A. N., Sanditov D. S.,Agrafonov Yu. V., Nesterov A. S. Application of themolecular dynamics method and the excited statemodel to the investigation of the glass transition inargon. Available at: http://www.isc.nw.ru/Rus/GPCJ/Content/2006/tsydypov_32_1.pdf (In Russ.). GlassPhysics and Chemistry. 2006;32(1): 83–88. DOI: https://doi.org/10.1134/S10876596060101113. Berthier L., Witten T. A. Glass transition of densefluids of hard and compressible spheres. PhysicalReview E. 2009;80(2): 021502. DOI: https://doi.org/10.1103/PhysRevE.80.0215024. Sarkisov G. N. Molecular distribution functionsof stable, metastable and amorphous classical models.Uspekhi Fizicheskih Nauk. 2002;172(6): 647–669. DOI:https://doi.org/10.3367/ufnr.0172.200206b.06475. Hoover W. G., Ross M., Johnson K. W., HendersonD., Barker J. A., Brown, B. C. Soft-sphere equationof state. The Journal of Chemical Physics, 1970;52(10):4931–4941. DOI: https://doi.org/10.1063/1.16727286. Cape J. N., Woodcock L. V. Glass transition in asoft-sphere model. The Journal of Chemical Physics,1980;72(2): 976–985. DOI: https://doi.org/10.1063/1.4392177. Franz S., Mezard M., Parisi G., Peliti L. Theresponse of glassy systems to random perturbations:A bridge between equilibrium and off-equilibrium.Journal of Statistical Physics. 1999;97(3–4): 459–488.DOI: https://doi.org/10.1023/A:10046029063328. Marc Mezard and Giorgio Parisi. Thermodynamicsof glasses: a first principles computation. J. of Phys.:Condens. Matter. 1999;11: A157–A165.9. Berthier L., Jacquin H., Zamponi F. Microscopictheory of the jamming transition of harmonic spheres.Physical Review E, 2011;84(5): 051103. DOI: https://doi.org/10.1103/PhysRevE.84.05110310. Berthier L., Biroli, G., Charbonneau P.,Corwin E. I., Franz S., Zamponi F. Gardner physics inamorphous solids and beyond. The Journal of ChemicalPhysics. 2019;151(1): 010901. DOI: https://doi.org/10.1063/1.5097175 11. Berthier L., Ozawa M., Scalliet C. Configurationalentropy of glass-forming liquids. The Journal ofChemical Physics. 2019;150(16): 160902. DOI: https://doi.org/10.1063/1.509196112. Bomont J. M., Pastore G. An alternative schemeto find glass state solutions using integral equationtheory for the pair structure. Molecular Physics.2015;113(17–18): 2770–2775. DOI: https://doi.org/10.1080/00268976.2015.103832513. Bomont J. M., Hansen J. P., Pastore G.Hypernetted-chain investigation of the random firstordertransition of a Lennard-Jones liquid to an idealglass. Physical Review E. 2015;92(4): 042316. DOI:https://doi.org/10.1103/PhysRevE.92.04231614. Bomont J. M., Pastore G., Hansen J. P.Coexistence of low and high overlap phases in asupercooled liquid: An integral equation investigation.The Journal of Chemical Physics. 2017;146(11): 114504.DOI: https://doi.org/10.1063/1.497849915. Bomont J. M., Hansen J. P., Pastore G. Revisitingthe replica theory of the liquid to ideal glass transition.The Journal of Chemical Physics. 2019;150(15): 154504.DOI: https://doi.org/10.1063/1.508881116. Cammarota C., Seoane B. First-principlescomputation of random-pinning glass transition, glasscooperative length scales, and numerical comparisons.Physical Review B. 2016;94(18): 180201. DOI: https://doi.org/10.1103/PhysRevB.94.18020117. Charbonneau P., Ikeda A., Parisi G., Zamponi F.Glass transition and random close packing above threedimensions. Physical Review Letters. 2011;107(18):185702. DOI: https://doi.org/10.1103/PhysRevLett.107.18570218. Ikeda A., Miyazaki K. Mode-coupling theory asa mean-field description of the glass transition.Physical Review Letters. 2010;104(25): 255704. DOI:https://doi.org/10.1103/PhysRevLett.104.25570419. McCowan D. Numerical study of long-timedynamics and ergodic-nonergodic transitions in densesimple fluids. Physical Review E. 2015;92(2): 022107.DOI: https://doi.org/10.1103/PhysRevE.92.02210720. Ohtsu H., Bennett T. D., Kojima T., Keen D. A.,Niwa Y., Kawano M. Amorphous–amorphous transitionin a porous coordination polymer. ChemicalCommunications. 2017;53(52): 7060–7063. DOI:https://doi.org/10.1039/C7CC03333H21. Schmid B., Schilling R. Glass transition of hardspheres in high dimensions. Physical Review E.2010;81(4): 041502. DOI: https://doi.org/10.1103/PhysRevE.81.04150222. Parisi G., Slanina, F. Toy model for the meanfieldtheory of hard-sphere liquids. Physical Review E.2000;62(5): 6554. DOI: https://doi.org/10.1103/Phys-RevE.62.655423. Parisi G., Zamponi F. The ideal glass transitionof hard spheres. The Journal of Chemical Physics.2005;123(14): 144501. DOI: https://doi.org/10.1063/1.204150724. Parisi G., Zamponi F. Amorphous packings ofhard spheres for large space dimension. Journal ofStatistical Mechanics: Theory and Experiment. 2006;03:P03017. DOI: https://doi.org/10.1088/1742-5468/2006/03/P0301725. Parisi G., Procaccia I., Shor C., Zylberg J. Effectiveforces in thermal amorphous solids with genericinteractions. Physical Review E. 2019;99(1): 011001. DOI:https://doi.org/10.1103/PhysRevE.99.01100126. Stevenson J. D., Wolynes P. G. Thermodynamic −kinetic correlations in supercooled liquids: a criticalsurvey of experimental data and predictions of therandom first-order transition theory of glasses. TheJournal of Physical Chemistry B. 2005;109(31): 15093–15097. DOI: https://doi.org/10.1021/jp052279h27. Xia X., Wolynes P. G. Fragilities of liquidspredicted from the random first order transition theoryof glasses. Proceedings of the National Academy ofSciences. 2000;97(7): 2990–2994. DOI: https://doi.org/10.1073/pnas.97.7.299028. Kobryn A. E., Gusarov S., Kovalenko A. A closurerelation to molecular theory of solvation formacromolecules. Journal of Physics: Condensed Matter.2016; 28 (40): 404003. DOI: https://doi.org/10.1088/0953-8984/28/40/40400329. Coluzzi B. , Parisi G. , Verrocchio P.Thermodynamical liquid-glass transition in a Lennard-Jones binary mixture. Physical Review Letters.2000;84(2): 306. DOI: https://doi.org/10.1103/PhysRevLett.84.30630. Sciortino F., Tartaglia P. Extension of thefluctuation-dissipation theorem to the physical agingof a model glass-forming liquid. Physical Review Letters.2001;86(1): 107. DOI: https://doi.org/10.1103/Phys-RevLett.86.10731. Sciortino, F. One liquid, two glasses. NatureMaterials. 2002;1(3): 145–146. DOI: https://doi.org/10.1038/nmat75232. Farr R. S., Groot R. D. Close packing density ofpolydisperse hard spheres. The Journal of ChemicalPhysics. 2009;131(24): 244104. DOI: https://doi.org/10.1063/1.327679933. Barrat J. L., Biben T., Bocquet, L. From Paris toLyon, and from simple to complex liquids: a view onJean-Pierre Hansen’s contribution. Molecular Physics.2015;113(17-18): 2378–2382. DOI: https://doi.org/10.1080/00268976.2015.103184334. Gaspard J. P. Structure of Melt and Liquid Alloys.In Handbook of Crystal Growth. Elsevier; 2015. 580 p.DOI: https://doi.org/10.1016/B978-0-444-56369-9.00009-535. Heyes D. M., Sigurgeirsson H. The Newtonianviscosity of concentrated stabilized dispersions:comparisons with the hard sphere fluid. Journal ofRheology. 2004;48(1): 223–248. DOI: https://doi.org/10.1122/1.163498636. Ninarello A., Berthier L., Coslovich D. Structureand dynamics of coupled viscous liquids. MolecularPhysics. 2015;113(17-18): 2707–2715. DOI: https://doi.org/10.1080/00268976.2015.103908937. Russel W. B., Wagner N. J., Mewis J. Divergencein the low shear viscosity for Brownian hard-spheredispersions: at random close packing or the glasstransition? Journal of Rheology. 2013;57(6): 1555–1567.DOI: https://doi.org/10.1122/1.482051538. Schaefer T. Fluid dynamics and viscosity instrongly correlated fluids. Annual Review of Nuclearand Particle Science. 2014;64: 125–148. DOI: https://doi.org/10.1146/annurev-nucl-102313-02543939. Matsuoka H. A macroscopic model thatconnects the molar excess entropy of a supercooledliquid near its glass transition temperature to itsviscosity. The Journal of Chemical Physics. 2012;137(20):204506. DOI: https://doi.org/10.1063/1.476734840. de Melo Marques F. A., Angelini R., Zaccarelli E.,Farago B., Ruta B., Ruocco, G., Ruzicka B. Structuraland microscopic relaxations in a colloidal glass. SoftMatter. 2015;11(3): 466–471. DOI: https://doi.org/10.1039/C4SM02010C41. Deutschländer S., Dillmann P., Maret G., KeimP. Kibble–Zurek mechanism in colloidal monolayers.Proceedings of the National Academy of Sciences.2015;112(22): 6925–6930. DOI: https://doi.org/10.1073/pnas.150076311242. Chang J., Lenhoff A. M., Sandler S. I.Determination of fluid–solid transitions in modelprotein solutions using the histogram reweightingmethod and expanded ensemble simulations. TheJournal of Chemical Physics. 2004;120(6): 3003–3014.DOI: https://doi.org/10.1063/1.163837743. Gurikov P., Smirnova I. Amorphization of drugsby adsorptive precipitation from supercriticalsolutions: a review. The Journal of Supercritical Fluids.2018;132: 105–125. DOI: https://doi.org/10.1016/j.supflu.2017.03.00544. Baghel S., Cathcart H., O’Reilly N. J. Polymericamorphoussolid dispersions: areviewofamorphization, crystallization, stabilization, solidstatecharacterization, and aqueous solubilization ofbiopharmaceutical classification system class II drugs.Journal of Pharmaceutical Sciences. 2016;105(9):2527–2544. DOI: https://doi.org/10.1016/j.xphs.2015.10.00845. Kalyuzhnyi Y. V., Hlushak S. P. Phase coexistencein polydisperse multi-Yukawa hard-sphere fluid: hightemperature approximation. The Journal of ChemicalPhysics. 2006;125(3): 034501. DOI: https://doi.org/10.1063/1.221241946. Mondal C., Sengupta S. Polymorphism,thermodynamic anomalies, and network formation inan atomistic model with two internal states. PhysicalReview E. 2011;84(5): 051503. DOI: https://doi.org/10.1103/PhysRevE.84.05150347. Bonn D., Denn M. M., Berthier L., Divoux T.,Manneville S. Yield stress materials in soft condensedmatter. Reviews of Modern Physics. 2017;89(3): 035005.DOI: https://doi.org/10.1103/RevModPhys.89.03500548. Tanaka H. Two-order-parameter model of theliquid–glass transition. I. Relation between glasstransition and crystallization. Journal of Non-Crystalline Solids. 2005;351(43-45): 3371–3384. DOI:https://doi.org/10.1016/j.jnoncrysol.2005.09.00849. Balesku R. Ravnovesnaya i neravnovesnayastatisticheskaya mekhanika [Equilibrium and nonequilibriumstatistical mechanics]. Moscow: Mir Publ.;1978. vol. 1. 404 c. (In Russ.)50. Chari S., Inguva R., Murthy K. P. N. A newtruncation scheme for BBGKY hierarchy: conservationof energy and time reversibility. arXiv preprintarXiv: 1608. 02338. DOI: https://arxiv.org/abs/1608.0233851. Gallagher I., Saint-Raymond L., Texier B. FromNewton to Boltzmann: hard spheres and short-rangepotentials. European Mathematical Society.arXiv:1208.5753. DOI: https://arxiv.org/abs/1208.575352. Rudzinski J. F., Noid W. G. A generalized-Yvon-Born-Green method for coarse-grained modeling. TheEuropean Physical Journal Special Topics. 224(12),2193–2216. DOI: https://doi.org/10.1140/epjst/e2015-02408-953. Franz B., Taylor-King J. P., Yates C., Erban R.Hard-sphere interactions in velocity-jump models.Physical Review E. 2016;94(1): 012129. DOI: https://doi.org/10.1103/PhysRevE.94.01212954. Gerasimenko V., Gapyak I. Low-Densityasymptotic behavior of observables of hard spherefluids. Advances in Mathematical Physics. 2018:6252919. DOI: https://doi.org/10.1155/2018/625291955. Lue L. Collision statistics, thermodynamics,and transport coefficients of hard hyperspheres inthree, four, and five dimensions. The Journal ofChemical Physics. 2005;122(4): 044513. DOI: https://doi.org/10.1063/1.183449856. Cigala G., Costa D., Bomont J. M., Caccamo C.Aggregate formation in a model fluid with microscopicpiecewise-continuous competing interactions.Molecular Physics. 2015;113(17–18): 2583–2592.DOI: https://doi.org/10.1080/00268976.2015.107800657. Jadrich R., Schweizer K. S. Equilibrium theoryof the hard sphere fluid and glasses in the metastableregime up to jamming. I. Thermodynamics. The Journalof Chemical Physics. 2013;139(5): 054501. DOI: https://doi.org/10.1063/1.481627558. Mondal A., Premkumar L., Das S. P. Dependenceof the configurational entropy on amorphousstructures of a hard-sphere fluid. Physical Review E.2017;96(1): 012124. DOI: https://doi.org/10.1103/PhysRevE.96.01212459. Sasai M. Energy landscape picture ofsupercooled liquids: application of a generalizedrandom energy model. The Journal of Chemical Physics.2003;118(23): 10651–10662. DOI: https://doi.org/10.1063/1.157478160. Sastry S. Liquid limits: Glass transition andliquid-gas spinodal boundaries of metastable liquids.Physical Review Letters. 2000;85(3): 590. DOI: https://doi.org/10.1103/PhysRevLett.85.59061. Uche O. U., Stillinger F. H., Torquato S. On therealizability of pair correlation functions. Physica A:Statistical Mechanics and its Applications. 2006;360(1):21–36. DOI: https://doi.org/10.1016/j.physa.2005.03.05862. Bi D., Henkes S., Daniels K. E., Chakraborty B.The statistical physics of athermal materials. Annu.Rev. Condens. Matter Phys. 2015;6(1): 63–83. DOI:https://doi.org/10.1146/annurev-conmatphys-031214-01433663. Bishop M., Masters A., Vlasov A. Y. Higher virialcoefficients of four and five dimensional hardhyperspheres. The Journal of Chemical Physics.2004;121(14): 6884–6886. DOI: https://doi.org/10.1063/1.177757464. Sliusarenko O. Y., Chechkin A. V., SlyusarenkoY. V. The Bogolyubov-Born-Green-Kirkwood-Yvon hierarchy and Fokker-Planck equation for manybodydissipative randomly driven systems. Journal ofMathematical Physics. 2015;56(4): 043302. DOI:https://doi.org/10.1063/1.491861265. Tang Y. A new grand canonical ensemblemethod to calculate first-order phase transitions. TheJournal of chemical physics. 2011;134(22): 224508. DOI:https://doi.org/10.1063/1.359904866. Tsednee T., Luchko T. Closure for the Ornstein-Zernike equation with pressure and free energyconsistency. Physical Review E. 2019;99(3): 032130.DOI: https://doi.org/10.1103/PhysRevE.99.03213067. Maimbourg T., Kurchan J., Zamponi, F. Solutionof the dynamics of liquids in the large-dimensionallimit. Physical review letters. 2016;116(1): 015902. DOI:https://doi.org/10.1103/PhysRevLett.116.01590268. Mari, R., & Kurchan, J. Dynamical transition ofglasses: from exact to approximate. The Journal ofChemical Physics. 2011;135(12): 124504. DOI: https://doi.org/10.1063/1.362680269. Frisch H. L., Percus J. K. High dimensionalityas an organizing device for classical fluids. PhysicalReview E. 1999;60(3): 2942. DOI: https://doi.org/10.1103/PhysRevE.60.294270. Finken R., Schmidt M., Löwen H. Freezingtransition of hard hyperspheres. Physical Review E.2001;65(1): 016108. DOI: https://doi.org/10.1103/PhysRevE.65.01610871. Torquato S., Uche O. U., Stillinger F. H. Randomsequential addition of hard spheres in high Euclideandimensions. Physical Review E. 2006;74(6): 061308.DOI: https://doi.org/10.1103/PhysRevE.74.06130872. Martynov G. A. Fundamental theory of liquids;method of distribution functions. Bristol: Adam Hilger;1992, 470 p.73. Vompe A. G., Martynov G. A. The self-consistentstatistical theory of condensation. The Journal ofChemical Physics. 1997;106(14): 6095–6101. DOI:https://doi.org/10.1063/1.47327274. Krokston K. Fizika zhidkogo sostoyaniya.Statisticheskoe vvedenie [Physics of the liquid state.Statistical introduction]. Moscow: Mir Publ.; 1978.400 p. (In Russ.)75. Rogers F. J., Young D. A. New, thermodynamicallyconsistent, integral equation for simple fluids. PhysicalReview A. 1984;30(2): 999. DOI: https://doi.org/10.1103/PhysRevA.30.99976. Wertheim M. S. Exact solution of the Percus–Yevick integral equation for hard spheres Phys. Rev.Letters. 1963;10(8): 321–323. DOI: https://doi.org/10.1103/PhysRevLett.10.32177. Tikhonov D. A., Kiselyov O. E., Martynov G. A.,Sarkisov G. N. Singlet integral equation in thestatistical theory of surface phenomena in liquids. J.of Mol. Liquids. 1999;82(1–2): 3– 17. DOI: https://doi.org/10.1016/S0167-7322(99)00037-978. Agrafonov Yu., Petrushin I. Two-particledistribution function of a non-ideal molecular systemnear a hard surface. Physics Procedia. 2015;71. 364–368. DOI: https://doi.org/10.1016/j.phpro.2015.08.35379. Agrafonov Yu., Petrushin I. Close order in themolecular system near hard surface. Journal of Physics:Conference Series. 2016;747: 012024. DOI: https://doi.org/10.1088/1742-6596/747/1/01202480. He Y., Rice S. A., Xu X. Analytic solution of theOrnstein-Zernike relation for inhomogeneous liquids.The Journal of Chemical Physics. 2016;145(23): 234508.DOI: https://doi.org/10.1063/1.497202081. Agrafonov Y. V., Petrushin I. S. Usingmolecular distribution functions to calculate thestructural properties of amorphous solids. Bulletinof the Russian Academy of Sciences: Physics. 2020;84:783–787. DOI: https://doi.org/10.3103/S106287382007003582. Bertheir L., Ediger M. D. How to “measure” astructural relaxation time that is too long to bemeasured? arXiv:2005.06520v1. DOI: https://arxiv.org/abs/2005.0652083. Karmakar S., Dasgupta C., Sastry S. Lengthscales in glass-forming liquids and related systems: areview. Reports on Progress in Physics. 2015;79(1):016601. DOI: https://doi.org/10.1088/0034-4885/79/1/01660184. De Michele C., Sciortino F., Coniglio A. Scalingin soft spheres: fragility invariance on the repulsivepotential softness. Journal of Physics: CondensedMatter. 2004;16(45): L489. DOI: https://doi.org/10.1088/0953-8984/16/45/L0185. Niblett S. P., de Souza V. K., Jack R. L., Wales D. J.Effects of random pinning on the potential energylandscape of a supercooled liquid. The Journal ofChemical Physics. 2018;149(11): 114503. DOI: https://doi.org/10.1063/1.504214086. Wolynes P. G., Lubchenko V. Structural glassesand supercooled liquids: Theory, experiment, andapplications. New York: John Wiley & Sons; 2012. 404p. DOI: https://doi.org/10.1002/978111820247087. Jack R. L., Garrahan J. P. Phase transition forquenched coupled replicas in a plaquette spin modelof glasses. Physical Review Letters. 2016;116(5): 055702.DOI: https://doi.org/10.1103/PhysRevLett.116.05570288. Habasaki J., Ueda A. Molecular dynamics studyof one-component soft-core system: thermodynamicproperties in the supercooled liquid and glassy states.The Journal of Chemical Physics. 2013;138(14): 144503.DOI: https://doi.org/10.1063/1.479988089. Bomont J. M., Hansen J. P., Pastore G. Aninvestigation of the liquid to glass transition usingintegral equations for the pair structure of coupledreplicae. J. Chem. Phys. 2014;141(17): 174505. DOI:https://doi.org/10.1063/1.490077490. Parisi G., Urbani P., Zamponi F. Theory of SimpleGlasses: Exact Solutions in Infinite Dimensions.Cambridge: Cambridge University Press; 2020. 324 p.DOI: https://doi.org/10.1017/978110812049491. Robles M., López de Haro M., Santos A., BravoYuste S. Is there a glass transition for dense hardspheresystems? The Journal of Chemical Physics.1998;108(3): 1290–1291. DOI: https://doi.org/10.1063/1.47549992. Grigera T. S., Martín-Mayor V., Parisi G.,Verrocchio P. Asymptotic aging in structural glasses.Physical Review B, 2004;70(1): 014202. DOI: https://doi.org/10.1103/PhysRevB.70.01420293. Vega C., Abascal J. L., McBride C., Bresme F.The fluid–solid equilibrium for a charged hard spheremodel revisited. The Journal of Chemical Physics.2003; 119 (2): 964–971. DOI: https://doi.org/10.1063/1.157637494. Kaneyoshi T. Surface amorphization in atransverse Ising nanowire; effects of a transverse field.Physica B: Condensed Matter. 2017;513: 87–94. DOI:https://doi.org/10.1016/j.physb.2017.03.01595. Paganini I. E., Davidchack R. L., Laird B. B.,Urrutia I. Properties of the hard-sphere fluid at a planarwall using virial series and molecular-dynamicssimulation. The Journal of Chemical Physics. 2018;149(1):014704. DOI: https://doi.org/10.1063/1.502533296. Properzi L., Santoro M., Minicucci M., Iesari F.,Ciambezi M., Nataf L., Di Cicco A. Structural evolutionmechanisms of amorphous and liquid As2 Se3 at highpressures. Physical Review B. 2016;93(21): 214205. DOI:https://doi.org/10.1103/PhysRevB.93.21420597. Sesé L. M. Computational study of the meltingfreezingtransition in the quantum hard-sphere systemfor intermediate densities. I. Thermodynamic results.The Journal of Chemical Physics. 2007;126(16): 164508.DOI: https://doi.org/10.1063/1.271852398. Shetty R., Escobedo F. A. On the application ofvirtual Gibbs ensembles to the direct simulation offluid–fluid and solid–fluid phase coexistence. TheJournal of Chemical Physics. 2002;116(18): 7957–7966.DOI: https://doi.org/10.1063/1.1467899

Although hydraulic pumps are frequently used in daily life, improper use due to oil analysis or oil contamination is ignored. There is no instantaneous inspection; instead, the oil is changed periodically at certain times, whether it is contaminated or not. Hydraulic systems operate based on Pascal’s law, which states that the fluid will distribute the pressure equally to every point in a closed area. The fluid oil taken from an oil reservoir is moved into the pump by engine power. During this movement, as it passes through different pressure areas and different sections, undesirable events such as viscosity change and gas formation occur in the hydraulic oil. These formations collide with the outer walls and cause cavitation with respect to unwanted oil impurities. This cavitation causes unwanted vibration signals to occur in the normal working order of the system. As a result of cavitation, the particles that affect the lubricity and fluidity of the oil in the oil are mixed into the liquid and circulate freely. At the connection points, the blockage caused by the liquid in the pump cylinder block or the valve plate and the collisions of particles is effective. As a result, it creates vibrations of different frequencies. The frequency and amplitudes of these vibrations differ according to the degree of oil contamination. A method has been developed to find the degree of contamination of the oil circulating in the pump by looking at the amplitude and frequency of these vibrations measured from the motor body. There exist standards about the pollution of hydraulic fluid. With these standards, the maximum number of particles allowed for a given pollution level is defined. This topic is discussed in the conclusion to this study. This method has also been proven experimentally. Error and vibration analysis studies on pumps using a different approach are available in the literature. In these studies, pressure variation, total energy transmission, or artificial intelligence models were used to detect anomalies in the pump. In this study, the impurity rate of the oil was set at five different levels and the operating regime of the pump at each level was investigated experimentally. Rayleigh–Plesset and Zwart–Gerber–Belamri models, which are the most common cavitation models, were used to explain the bubble formation in the moving oil and the relationship of these bubbles with vibration. Frequency components were examined by the Discrete Fast Fourier Analysis method, where the operation of the pump was affected by the increase in oil impurity.

ABSTRACTThe thermal expansion and viscosity of water and salt solutions in porous silica glasses have been systematically investigated, and the effect of salts on the properties of water in confined geometry has been addressed. A dilatometric method has been devised and utilized to measure the thermal expansion of confined liquids. A beam-bending method that was developed to study the permeability of porous bodies has been used to measure the relative viscosity of salt solutions to water inside the silica pores. This work has demonstrated that water when confined in nanopores shows anomalous behavior and its thermal expansion is higher than bulk water. This work has also suggested that the presence of ions in water could enhance the anomaly of water in confined space and the extent of the ion effect is dependent on the ion charge.

Nucleate pool boiling heat transfer and its ebullient dynamics in polymeric solutions at atmospheric pressure saturated conditions are experimentally investigated. Three grades of hydroxyethyl cellulose (HEC) are used, which have intrinsic viscosity in the range 5.29 ≤ [η] ≤ 10.31 [dl/g]. Their aqueous solutions in different concentrations, with zero-shear viscosity in the range 0.0021 ≤ η0 ≤ 0.0118 [N⋅s/m2], exhibit shear-thinning rheology in varying degrees, as well as gas–liquid interfacial tension relaxation and wetting. Boiling heat transfer in solutions with constant molar concentrations of each additive, which are greater than their respective critical polymer concentration C*, is seen to have anomalous characteristics. There is degradation in the heat transfer at low heat fluxes, relative to that in the solvent, where the postnucleation bubble dynamics in the partial boiling regime is dominated by viscous resistance of the polymeric solutions. At higher heat fluxes, however, there is enhancement of boiling heat transfer due to a complex interplay of pseudoplasticity and dynamic surface tension effects. The higher frequency vapor bubbling train with high interfacial shear rates in this fully developed boiling regime tends to be influenced by increasing shear-thinning and time-dependent differential interfacial tension relaxation at the dynamic gas–liquid interfaces.

Abstract In this study the first viscosity measurements in the glass transition range of melts from highly explosive large-volume eruptions from the Colli Albani Volcanic District (CAVD) are presented. The magmas are ultrapotassic, rich in iron and CaO and characterised by a low silica content (< 45 wt%). Melt compositions range from tephri-phonolitic to foiditic. The Colli Albani eruptions appear anomalous since they produced a large volume of erupted material in spite of their silica undersaturated compositions. The viscosity of the Colli Albani melt changes as the melt composition evolves from the original melt to a country-rock contaminated melt to a crystal-bearing melt with a permanent decrease in liquid viscosity. Conventional estimations of viscosities assume these magmas to have a low viscosity. The presented data show that the melt viscosities are higher than expected. Taking into account further chemical or rheological features of a melt, the investigated CAVD melts are not that striking as assumed in comparison with other large-volume eruptions. Consequently, considering the alkaline-earth to alkaline ratio together with the SiO2 content could provide an alternative when comparing large volume eruptions.

As oil fields deplete, in particular in deep sea reservoirs, pump and compression systems work under more strenuous conditions with gas in liquid and liquid in gas mixtures, mostly inhomogeneous. Off-design operation affects system overall efficiency and reliability, including penalties in leakage and rotordynamic performance of secondary flow components, namely seals. The paper details a bulk-flow model for annular damper seals operating with gas in liquid mixtures. The analysis encompasses all-liquid and all-gas seals, as well as seals lubricated with homogenous (bubbly) mixtures, and predicts the static and dynamic force response of mixture lubricated seals; namely: leakage, power loss, reaction forces, and rotordynamic force coefficients, etc., as a function of the mixture volume fraction (βS), supply and discharge pressures, rotor speed, whirl frequency, etc. A seal example with a nitrogen gas mixed with light oil is analyzed. The large pressure drop (70 bar) causes a large expansion of the gas within the seal even for (very) small gas volume fractions (βS). Predictions show leakage and power loss decrease as β→1; albeit at low βS (< 0.3) (re)laminarization of the flow and an apparent increase in mixture viscosity, produce a hump in power loss. Cross-coupled stiffnesses and direct damping coefficients decrease steadily with increases in the gas volume fraction; however, some anomalies are apparent when the flow turns laminar. Mixture lubricated seals show frequency-dependent force coefficients. The equivalent damping decreases above and below βS ∼ 0.10. The direct stiffness coefficients show atypical behavior: a low βS = 0.1 produces stiffness hardening as the excitation frequency increases. Recall that an all liquid seal has a dynamic stiffness softening as frequency increases due to the apparent fluid mass. The predictions call for an experimental program to quantify the static and dynamic forced performance of annular seals operating with (bubbly) mixtures and to validate the current predictive model results.