Fluid Separation Research Articles

Atomistic Hydrodynamics and the Dynamical Hydrophobic Effect in Porous Graphene.

Mirroring their role in electrical and optical physics, two-dimensional crystals are emerging as novel platforms for fluid separations and water desalination, which are hydrodynamic processes that occur in nanoscale environments. For numerical simulation to play a predictive and descriptive role, one must have theoretically sound methods that span orders of magnitude in physical scales, from the atomistic motions of particles inside the channels to the large-scale hydrodynamic gradients that drive transport. Here, we use constraint dynamics to derive a nonequilibrium molecular dynamics method for simulating steady-state mass flow of a fluid moving through the nanoscopic spaces of a porous solid. After validating our method on a model system, we use it to study the hydrophobic effect of water moving through pores of electrically doped single-layer graphene. The trend in permeability that we calculate does not follow the hydrophobicity of the membrane but is instead governed by a crossover between two competing molecular transport mechanisms.

The mangazeya Ag–Pb–Zn vein deposit hosted in sedimentary rocks, Sakha-Yakutia, Russia: Mineral assemblages, fluid inclusions, stable isotopes (C, O, S), and origin

The succession of mineral assemblages, chemistry of gangue and ore minerals, fluid inclusions, and stable isotopes (C, O, S) in minerals have been studied in the Mangazeya silver–base-metal deposit hosted in terrigenous rocks of the Verkhoyansk Fold–Thrust Belt. The deposit is localized in the junction zone of the Kuranakh Anticlinorium and the Sartanga Synclinorium at the steep eastern limb of the Endybal Anticline. The deposit is situated at the intersection of the regional Nyuektame and North Tirekhtyakh faults. Igneous rocks are represented by the Endybal massif of granodiorite porphyry 97.8 ± 0.9 Ma in age and dikes varying in composition. One preore and three types of ore mineralization separated in space are distinguished: quartz–pyrite–arsenopyrite (I), quartz–carbonate–sulfide (II), and silver–base-metal (III). Quartz and carbonate (siderite) are predominant in ore veins. Ore minerals are represented by arsenopyrite, pyrite, sphalerite, galena, fahlore, and less frequent sulfosalts. Three types of fluid inclusions in quartz differ in phase compositions: two- or three-phase aqueous–carbon dioxide (FI I), carbon dioxide gas (FI II), and two-phase (FI III) containing liquid and a gas bubble. The homogenization temperature and salinity fall within the ranges of 367–217°C and 13.8–2.6 wt % NaCl equiv in FI I; 336–126°C and 15.4–0.8 wt % NaCl equiv in FI III. Carbon dioxide in FI II was homogenized in gas at +30.2 to +15.3°C and at +27.2 to 29.0°C in liquid. The δ34S values for minerals of type I range from–1.8 to +4.7‰ (V-CDT); of type II, from–7.4 to +6.6‰; and of type III, from–5.6 to +7.1‰. δ13C and δ18O vary from–7.0 to–6.7‰ (V-PDB) and from +16.6 to +17.1 (V-SMOW) in siderite-I; from–9.1 to–6.9‰ (V-PDB) and from +14.6 to +18.9 (V-SMOW) in siderite-II; from–5.4 to–3.1‰ (V-PDB) and from +14.6 to +19.5 (V-SMOW) in ankerite; and from–4.2 to–2.9‰ (V-PDB) and from +13.5 to +16.8 (V-SMOW) in calcite. The data on mineral assemblages, fluid inclusions, and ratios of stable isotopes allow us to speak about the formation of the Mangazeya deposit in relation to the activity of the hydrothermal–magmatic system. The latter combines emplacement of subvolcanic granitic stocks and involvement of fluids variable in salinity and temperature in ore deposition zone. The fluids released from crystallizing felsic magma and were formed in a convective cell by heating of meteoric and marine waters. The mechanism of ore deposition is related to phase separation (boiling) and mixing of fluids.

The static reseal pressure model for cryogenic screen channel liquid acquisition devices

Inside a propellant tank in microgravity, surface tension forces dominate, and porous screen channel liquid acquisition devices (LADs) are required to separate fluid phases, control flow, and ensure vapor free liquid transfer out of the tank. The bubble point pressure based on Adamson and Gast (1997) and reseal pressure of the screen define LAD performance. This paper presents a predictive equation for modeling the reseal pressure in both storable as well as cryogenic liquids. Seven parameters affect the reseal pressure, including surface tension (liquid type), contact angle, screen reseal diameter, liquid temperature, degree of subcooling, and pressurant gas type and temperature. Decreasing the temperature decreases reseal pressure. Pressurization with a non-condensable gas always yields higher reseal points over pressurization with a condensable gas. Subcooling the liquid at the screen adds margin in reseal point whereas elevating the temperature of the pressurant gas is a degradation factor. The reseal pressure model is validated across a wide range of experimental ground data and the mean absolute error between 4815 data points and model is only 2.4%.

In Vitro Validation of a Closed Device Enabling the Purification of the Fluid Portion of Liposuction Aspirates.

Adipose tissue harvested through lipoaspiration is widely exploited in plastic and cosmetic surgery, because of its remarkable trophic properties, especially relying on the presence of adipose-derived stem cells. The common procedures for adipose-derived stem cell isolation are mainly based on tissue fractionation and enzymatic digestion, requiring multiple hours of uninterrupted work, unsuitable for direct surgical applications. Recent studies demonstrated the feasibility of isolating adipose stromal cells without the need for enzymatic digestion. These studies reported the processing of the fluid portion of liposuctioned adipose tissue (lipoaspirate fluid), which contains a significant amount of progenitor cells endowed with plastic and trophic features. In this article, the authors introduce a brand new closed device--the MyStem EVO kit--which allows nonenzymatic tissue separation and rapid isolation of lipoaspirate fluid from human liposuctioned adipose tissue. Adipose tissue was liposuctioned from 14 donors, split into aliquots, and alternatively processed using either centrifugation or the MyStem EVO kit, to separate fatty and lipoaspirate fluid portions. The samples were analyzed comparatively by flow cytometry, histology, and differentiation assays. Osteoinductive and angioinductive features were analyzed through in vitro co-culture assays. The alternative procedures enabled comparable yields; the kit rapidly isolated lipoaspirate fluid comprising a homogenous cell population with adipose stem cell immunophenotype, bilineage potential, and efficient osteoinductive and angioinductive features. MyStem EVO allows the rapid isolation of lipoaspirate fluid with trophic properties within a closed system, and is potentially useful for regenerative medicine applications.

A New Numerical Model for the Quench Simulation in CFETR CSMC Conductor

Modeling of cable-in-conduit conductor (CICC) is available for its advantage in efficiency and usually performed for optimizing CICC in a magnetic system. It is an important part of design and analysis of the central solenoid model coil (CSMC) for the China Fusion Engineering Test Reactor (CFETR). This paper is intended to provide a finite-element method with an ANSYS module to deal with the integrated analysis of thermal and fluid models of CICC. The CICC model is based on the NbTi conductor of the CFETR CSMC. It cooled by supercritical helium. One-dimensional elements of thermal and fluid are used to represent CICC components of conduit, strands, and two separated fluid areas of the bundle and the central hole, respectively. Test verification of a short length of the full-size conductor in the SULTAN facility is also presented.

Hydrothermal venting and mineralization in the crater of Kick'em Jenny submarine volcano, Grenada (Lesser Antilles)

AbstractKick'em Jenny is a frequently erupting, shallow submarine volcano located 7.5 km off the northern coast of Grenada in the Lesser Antilles subduction zone. Focused and diffuse hydrothermal venting is taking place mainly within a small (∼70 × 110 m) depression within the 300 m diameter crater of the volcano at depths of about 265 m. Much of the crater is blanketed with a layer of fine‐grained tephra that has undergone hydrothermal alteration. Clear fluids and gas are being discharged near the center of the depression from mound‐like vents at a maximum temperature of 180°C. The gas consists of 93–96% CO2 with trace amounts of methane and hydrogen. Gas flux measurements of individual bubble streams range from 10 to 100 kg of CO2 per day. Diffuse venting with temperatures 5–35°C above ambient occurs throughout the depression and over large areas of the main crater. These zones are colonized by reddish‐yellow bacteria with the production of Fe‐oxyhydroxides as surface coatings, fragile spires up to several meters in height, and elongated mounds up to tens of centimeters thick. A high‐resolution photomosaic of the inner crater depression shows fluid flow patterns descending the sides of the depression toward the crater floor. We suggest that the negatively buoyant fluid flow is the result of phase separation of hydrothermal fluids at Kick'em Jenny generating a dense saline component that does not rise despite its elevated temperature.

Investigation on the flow control of micro-vanes on a supersonic spinning projectile

Abstract Studies have shown that micro-wedge vortex generators (MVG) can effectively control the flow separation of supersonic boundary layer. In order to improve the flight stability of spinning projectile, the original standard 155 mm projectile was taken as an example, and the micro-vanes were mounted at the projectile shoulder to investigate the separation control on the aerodynamic characteristics of projectile. Numerical simulations were performed with the use of DES method for the flow fields of projectiles with and without micro-vanes, and the characteristics of the boundary layer structures and aerodynamic data were compared and discussed. Numerical results show that the micro-vanes can be used to inhibit separation of fluid on projectile surface, and improve the flight stability and firing dispersion of projectile.

Magneto-rheological defects and failures: A review

Magneto-rheological fluid is the colloidal suspension of micron sized magnetic particles in a carrier fluid where defects and failures occur at many circumstances. This paper presents a review on defects and failures of magneto-rheological fluid in engineering applications. The most significant defect is hard cake which developed due to re-dispersion difficulties of remnant particles magnetization, leaving the magneto-rheological fluid ineffective. Clumping effect on the other hand is a separation of carrier fluid from the magnetic particles when magneto-rheological fluid is being exposed to higher magnetic field for an extended period of time. As clumping occurred, it leads to Fluid Particle Separation (FPS) which is believed altering the strength distribution of magneto-rheological fluid and therefore reducing the squeezing force. Another significant failure is magnetic particles oxidation of the magneto-rheological fluid. This paper also will discuss on stability problems which is the most challenged issue in magneto-rheological fluid technology. With the comprehensive review in this paper, researcher can design materials of magneto-rheological fluid for better properties.

Voltage-Mediated Control of Bundle Dynamics in Hair Cells

Hair cells of the vertebrate vestibular and auditory end organs convert mechanical inputs into electrical responses. This mechano-electrical transduction (MET) involves the gating of mechanically sensitive ion channels, thus modulating the conductance and the membrane potential of the cell. MET includes one or more energy consuming feedback mechanisms that keep the channels in their most sensitive operating range. Coupling between the gating of the channels and this adaptation mechanism has been proposed to follow dynamics of a system that is close to a Hopf or other bifurcations. Such systems exhibit high responsiveness to external stimuli in the proximity of a critical point, and exhibit spontaneous limit-cycle oscillations when the system crosses a bifurcation. We present optical and electrophysiological recordings from hair cells that exhibit such spontaneous oscillations and explore how the cell's membrane potential may control the system's tuning near the critical point. Sacculi from the American bullfrog were mounted in a two-compartment chamber such that the natural fluid separation between the apical and basolateral surfaces of the hair cells was maintained. Spontaneous hair bundle oscillations were monitored using a high-speed video camera system, and the hair cell membrane potential was controlled using standard patch-clamp techniques. We found that the membrane potential of the hair cell can modulate or fully suppress innate oscillations, thus controlling the dynamic state of the bundle. This control is mediated by the cell's internal calcium concentration, which sets the resting open probability of the mechanosensitive channels. The auditory and vestibular systems could control the membrane potential of hair cells to tune the dynamic states of the system near (or away from) the critical point, thereby affecting the responsiveness of the hair cells. This work was supported by NIH grant RO1DC011380 to DB.

RECONSTRUCTING THE SOLAR WIND FROM ITS EARLY HISTORY TO CURRENT EPOCH

ABSTRACT Stellar winds from active solar-type stars can play a crucial role in removal of stellar angular momentum and erosion of planetary atmospheres. However, major wind properties except for mass-loss rates cannot be directly derived from observations. We employed a three-dimensional magnetohydrodynamic Alfvén wave driven solar wind model, ALF3D, to reconstruct the solar wind parameters including the mass-loss rate, terminal velocity, and wind temperature at 0.7, 2, and 4.65 Gyr. Our model treats the wind thermal electrons, protons, and pickup protons as separate fluids and incorporates turbulence transport, eddy viscosity, turbulent resistivity, and turbulent heating to properly describe proton and electron temperatures of the solar wind. To study the evolution of the solar wind, we specified three input model parameters, the plasma density, Alfvén wave amplitude, and the strength of the dipole magnetic field at the wind base for each of three solar wind evolution models that are consistent with observational constrains. Our model results show that the velocity of the paleo solar wind was twice as fast, ∼50 times denser and 2 times hotter at 1 AU in the Sun's early history at 0.7 Gyr. The theoretical calculations of mass-loss rate appear to be in agreement with the empirically derived values for stars of various ages. These results can provide realistic constraints for wind dynamic pressures on magnetospheres of (exo)planets around the young Sun and other active stars, which is crucial in realistic assessment of the Joule heating of their ionospheres and corresponding effects of atmospheric erosion.

Multiple carbon and nitrogen sources associated with the parental mantle fluids of fibrous diamonds from Diavik, Canada, revealed by SIMS microanalysis

Fibrous diamonds are often interpreted as direct precipitates of primary carbonate-bearing fluids in the lithospheric mantle, sourced directly from common reservoirs of “mantle” carbon and nitrogen. Here we have examined fibrous growth layers in five diamonds (as three rims or “coats” and two whole-crystal cuboids) from the Diavik Diamond Mine, Canada, using in situ C- and N-isotope and N-abundance measurements to investigate the origin and evolution of their parental fluids, and in particular, to test for isotopic variability within a suite of fibrous diamonds. High-resolution growth structure information was gleaned from cathodoluminescence (CL) imaging and, in combination with the isotopic data, was used to assess the nature of the transition from gem to fibrous growth in the coated diamonds. The two cuboids are characterized by fine concentric bands of fibrous and/or milky opaque diamond, with one sample (S1719) having intermittent gem-like growth layers that are transparent and colourless. The three coated diamonds comprise octahedral gem cores mantled by massive or weakly zoned fibrous rims, with sharp and well-defined gem–fibrous boundaries. For the two cuboid samples, δ 13C and δ 15N values were −7.7 to −3.2 ‰ (mean −6.3 ± 1.3 ‰; 1 SD; n = 84) and −5.6 to −2.1 ‰ (mean −4.0 ± 0.8 ‰; 1 SD; n = 48), respectively. The three fibrous rims have combined δ 13C values of −8.3 to −4.8 ‰ (mean −6.9 ± 0.7 ‰; 1 SD; n = 113) and δ 15N values of −3.8 to −1.9 ‰ (mean −2.7 ± 0.4 ‰; 1 SD; n = 43). N-abundances of the combined cuboid–fibrous rim dataset range from 339 to 1714 at. ppm. The gem cores have δ 13C and δ 15N values of −5.4 to −3.5 ‰ and −17.7 to +4.5 ‰, respectively, and N-abundances of 480 to 1699 at. ppm. Broadly uniform C- and N-isotope compositions were observed in each of the gem cores (variations of ~<1 ‰ for carbon and ~<3 ‰ for nitrogen). This limited C- and N- isotope variability implies that the gem cores formed from separate pulses of fluid that remained isotopically uniform throughout the duration of growth. Significant isotopic and abundance differences were observed between the gem and fibrous growth zones, including in one detailed isotopic profile δ 13C and δ 15N offsets of ~−2.4 and ~−3.7 ‰, respectively, and a ~230 at. ppm increase in N-abundance. Combined with the well-defined gem–fibrous boundaries in plane light and CL, these sharp isotopic differences indicate separate parental fluid histories. Notably, in the combined fibrous diamond dataset prominent C- and N-isotope differences between the whole-crystal cuboid and fibrous rim data were observed, including a consistent ~1.3 ‰ offset in δ 15N values between the two growth types. This bimodal N-isotope distribution is interpreted as formation from separate parental fluids, associated with distinct nitrogen sources. The bimodal N-isotope distribution could also be explained by differences in N-speciation between the respective parental fluids, which would largely be controlled by the oxidation state of the fibrous rim and cuboid growth environments (i.e., N2 vs. NH4 + or NH3). We also note that this C- and N-isotope variability could indicate temporal changes to the source(s) of the respective parental fluids, such that each stage of fibrous diamond growth reflects the emplacement of separate pulses of proto-kimberlitic fluid—from distinct carbon and nitrogen sources, and/or with varying N-species—into the lithospheric mantle.

On the nonlocal Cahn-Hilliard-Brinkman and Cahn-Hilliard-Hele-Shaw systems

The phase separation of an isothermal incompressible binary fluid in a porous medium can be described by the so-called Brinkman equation coupled with a convective Cahn-Hilliard (CH) equation. The former governs the average fluid velocity $\mathbf{u}$, while the latter rules evolution of $\varphi$, the difference of the (relative) concentrations of the two phases. The two equations are known as the Cahn-Hilliard-Brinkman (CHB) system. In particular, the Brinkman equation is a Stokes-like equation with a forcing term (Korteweg force) which is proportional to $\mu\nabla\varphi$, where $\mu$ is the chemical potential. When the viscosity vanishes, then the system becomes the Cahn-Hilliard-Hele-Shaw (CHHS) system. Both systems have been studied from the theoretical and the numerical viewpoints. However, theoretical results on the CHHS system are still rather incomplete. For instance, uniqueness of weak solutions is unknown even in 2D. Here we replace the usual CH equation with its physically more relevant nonlocal version. This choice allows us to prove more about the corresponding nonlocal CHHS system. More precisely, we first study well-posedness for the CHB system, endowed with no-slip and no-flux boundary conditions. Then, existence of a weak solution to the CHHS system is obtained as a limit of solutions to the CHB system. Stronger assumptions on the initial datum allow us to prove uniqueness for the CHHS system. Further regularity properties are obtained by assuming additional, though reasonable, assumptions on the interaction kernel. By exploiting these properties, we provide an estimate for the difference between the solution to the CHB system and the one to the CHHS system with respect to viscosity.

Relationships Between Gold and Pyrite at the Xincheng Gold Deposit, Jiaodong Peninsula, China: Implications for Gold Source and Deposition in a Brittle Epizonal Environment

The Xincheng gold deposit, hosted by the Early Cretaceous 132 to 123 Ma Guojialing-type granitoids in northwest Jiaodong Peninsula, southeast North China craton, formed about 2 billion years later than regional metamorphism of the Archean Jiaodong basement rocks. The Xincheng deposit comprises mineralized zones with three types of hydrothermal pyrite associated with gold, tellurides, and a variety of sulfides: py1 as disseminated euhedral to subhedral grains in altered granitoids around quartz veins; py2 as subhedral grains with brittle cataclastic textures and fractures in quartz-pyrite veins; and py3 as subhedral, partially corroded crystals in sulfide-rich veins or veinlets. All three generations of pyrite are unzoned and have low trace element contents, including very low lattice-bound gold contents: (py1: 0.180 ppm; py2: 0.053 ppm; py3: 0.060 ppm). Given that there is 10 to 15% pyrite in the ore zone at Xincheng, its very low gold content indicates that it contributes <0.2% of gold to the 7.75 g/t gold in the orebody. Instead, over 99% of the gold is present as discrete electrum and/or gold (total range 0.02–59% silver) grains, which are largely sited in fractures at all scales in pyrite, other ore minerals, and quartz. Importantly, visible gold in py3 is also sited on solution-corroded pyrite grains. The pyrite textural and geochemical data indicate that it is impossible to derive the high gold-grade orebodies through local remobilization of originally lattice-bound gold in pyrite. Instead, the gold is interpreted to have been deposited through sulfidation reactions and phase separation of a H2O-CO2 ore fluid during progressive brittle cataclastic deformation associated with seismic activity and regional sinistral transtensional shear movement. This concomitant fluid infiltration and deformation caused episodic deposition and fracturing and corrosion of earlier formed pyrite and deposited visible gold in dilational cracks. The coupled development of the transtensional, rather than normal transpressional setting, and precipitation of gold within dilational veins and wall-rock alteration facilitated the deposition of visible gold and an exceptionally high gold tenor. All deposit characteristics indicate that the Xincheng gold deposit is a member of the epizonal orogenic deposit class.

Scrap tyre recycling process with molten zinc as direct heat transfer and solids separation fluid: A new reactor concept

Every year about 1.5 billion tyres are discarded worldwide representing a large amount of solid waste, but also a largely untapped source of raw materials. The objective of the method was to prove the concept of a novel scrap tyre recycling process which uses molten zinc as the direct heat transfer fluid and, simultaneously, uses this media to separate the solids products (i.e. steel and rCB) in a sink-float separation at an operating temperature of 450–470°C.This methodology involved:•construction of the laboratory scale batch reactor,•separation of floating rCB from the zinc,•recovery of the steel from the bottom of the reactor following pyrolysis

Numerical simulation of the leaky dielectric microdroplet generation in electric fields

Microdroplet generation has a vast range of applications in the chemical, biomedical, and biological sciences. Several devices are applied to produce microdroplets, such as Co-flow, T-junction and Flow-focusing. The important point in the producing process is controlling the separated fluid volume in these devices. On the other hand, a large number of liquids, especially aqueous one, are influenced by electric or magnetic fields. As a consequence, an electric field could be used in order to affect the separated fluid volume. In this study, effects of an electric field on the microdroplet generation in a Co-flow device are investigated numerically. Furthermore, effects of some electrical properties such as permittivity on the separating process of microdroplets are studied. Leaky dielectric and perfect dielectric models are used in this investigation. According to the results, in the microdroplet generating process, leaky dielectric fluids show different behaviors, when an electric field is applied to the device. In other words, in a constant electric field strength, the volume of generated microdroplets can increase or decrease, in comparison with the condition without the electric field. However, for perfect dielectric fluids, droplet volume always decreases with increasing the electric field strength. In order to validate the numerical method of this study, deformation of a leaky dielectric droplet in an electric field is investigated. Results are compared with Taylor theoretical model.

The Integrative Five-Fluid Circulation System in the Human Body

Water is the key medium to transport numerous constituents and to provide a platform for physiological processes to take place in the living organisms in general; it also participates actively in many of these processes. In humans, there are different vehicles to contain water and its constituents. Our objective is to find out whether there is an overall water-base circulation system in the human body by analyzing the updated findings of different research groups on the physiological functions of various seemingly isolated fluid systems. By 1963, there were five separate fluid systems discovered in mammalians: (i) The Primo Vasculature Fluid (PVF) with protein precursors and micro cells held in the Primo Vasculature System (PVS). (ii) Blood with its constituents held in the cardio vasculature. (iii) Extracranial interstitial fluid (ISF) whose vehicle had a very irregular structure—the interstitium all over the body. (iv) The cerebrospinal fluid had been considered to be within the brain ventricles and spinal canal. (v) The extra-cranial lymphatic system which drained ISF, and had been known to join the subclavian vein. Fluid (i) was first reported in 1963 and fluids (ii) to (v) have been known for many decades, but the failure to detect a lymphatic system inside the skull has also been a mystery for many decades. The intra-cranial ISF (which we name as BISF) has drawn little attention, apart from discussing the mechanism of the blood-brain-barrier. During the past decade, there has been direct evidence indicating that CSF and BISF are actually mixed. After that, the intracranial lymphatic system was discovered and confirmed in animal models only slightly over one year back, and we called such fluid as glymphatic-fluid. After reviewing the stated “classical” five fluid systems together with the new findings in Sections 2 - 7, we propose, for the first time, that the PVF, the blood, ISF, a mixture of CSF-BISF, and a mixture of glymphatic-fluid and lymph form an integrative circulation system in water base in the human and other mammalian bodies, as schematically represented in the last section. In this paper, we point out the positive correlation of chronic neuro degenerative diseases such as Alzheimer’s disease, Parkinson’s diseases and the insufficient brain wastes clearance by the glymphatic system. We also discuss the role played by the venous vessels as part of such clearance in upright posture. Moreover, simple non-invasive maneuver techniques are introduced here, as one example of enhancement of glymphatic fluid flow out of the skull to join the lymphatic system. A series of questions are raised in Section 8, the answers to which would help us to understand the transition from physio- to pathological states in the development of many diseases. Detailed analysis of this paper leads us to consider that research in understanding this integrative circulation system is only at the infancy stage, and fluid dynamics investigation seems to be the plausible modality of approach in the near future.

Observed and predicted particle dynamics driven by inertial flows within high aspect ratio microfluidic channels

Inertial focusing in microfluidic channels has been shown to be an effective and versatile method of passively arranging particles into specific streamlines and regulating interparticle spacing. As a result of the high precision and fidelity of particle ordering, there has been significant interest in using microfluidic devices for applications in cell encapsulation, particle–fluid separation, size-selective cell sorting, and flow cytometry. When predicting application-specific design parameters, such as channel dimensions and flow rates, it is necessary to rely upon relations connecting the inertial forces acting upon particles with geometric dimensions. In this study, we develop an empirical technique to measure transverse-flow particle velocities and provide a semiempirical model describing the lateral forces experienced by a particle subject to non-turbulent, finite Reynolds number flow in a rectangular channel.

Modelling of divided wall column

The rectification is the most often used fluid separation technology. The improvement of the distillation equipment and process is significant (Haddad and Manley, 2008) because the rectification has relatively low energy efficiency. In practice, the aim is the separation of the multi-component mixture. This task can be solved with a number of columns depending how many components there are or one column with side product(s). This paper focuses on how to find a better structure with minimal energy consumption. The divided wall column (DWC) system is a promising energy-saving alternative for separating multi-component mixtures (Serra et al, 1999). The innovation of this equipment is a wall which divides the space in of the tower so the feed and the side stream-product zones are separated. This wall prevents contamination of the side stream by the feed stream. The dividing wall column has greater efficiency than common column sequence (Hernandez et al V, 2006). The conventional columns with side stream are also convertible to DWC. In this paper different constructions of the DWC were investigated with simulation experiments. The structure of the column was implemented in Aspen Plus TM simulator using the Radfrac unit of the software. The effects of the main parameters of the divided wall column like split ratio of the liquid and vapor stream, height of the wall, vertical position of wall, and the heat transfer of the wall were analyzed.

Proposal for a Viscous Test Mixture—Densities, Viscosities, and Vapor–Liquid Equilibrium Data of the Binary Mixture 2-Methyl-2-butanol + 2-Methyl-1-propanol

Standardized test mixtures are needed to determine the effectiveness and efficiency of distillation columns and their internals. Despite the wide range of different test mixtures and the variations in their physical properties, no standard test mixture is available that contributes viscosities above 1.5 mPa s at typical distillation conditions. To investigate the impact of viscosity on separation effectiveness and efficiency and validate models for higher viscosities, a new test mixture is proposed. On the basis of a screening, the binary mixture 2-methyl-2-butanol/2-methyl-1-propanol was chosen, showing liquid phase viscosities up to 5 mPa s and satisfying the requirements for separation efficiency tests. For this mixture, vapor–liquid equilibria were measured from 2 to 95 kPa. A slight negative deviation from ideal behavior is accounted for using the nonrandom two-liquid model. Furthermore, for both pure substances as well as their mixtures liquid densities were determined from 293.15 to 363.15 K and viscosities in a temperature range from 273.15 to 333.15 K. Nonidealities were modeled with a Redlich–Kister approach. Thus, vital information for the assessment of separation efficiency with a new test mixture is given and subsequent studies on the influence of viscosity on fluid dynamics and separation efficiency in distillation columns are enabled.

Stable isotope (B, H, O) and mineral-chemistry constraints on the magmatic to hydrothermal evolution of the Varuträsk rare-element pegmatite (Northern Sweden)

The internal evolution of the Varuträsk rare-element pegmatite (Skellefte District, Northern Sweden) has been investigated using stable isotope (B, H, O) geochemistry of tourmaline and coexisting micas, feldspar and quartz. Varuträsk is a classic and typical example of highly fractionated LCT-type pegmatites, with a pronounced concentric zoning pattern composed of well-developed border, wall and intermediate zones and a quartz core. The pegmatite displays considerable rare-element enrichment, culminating in the formation of albite-lepidolite and pollucite units in the innermost zones. Major and trace element variations in tourmaline from the main pegmatite zones correlate well with the internal zoning pattern. Mineral compositions record an abrupt change in fractionation trends between the barren outer and intermediate zones and the inner, late-stage assemblages that carry rare-element mineralization. This change is also shown by the B-isotope variations of tourmaline. Early and mid-stage tourmalines record a systematic increase in δ11B from −14.6‰ to −6.2‰ which can be explained by closed-system melt-mineral isotope fractionation whereby crystallization of large amounts of muscovite preferentially removes 10B from the residual melt. In contrast, tourmaline from late-stage assemblages in the inner zones and cross-cutting veinlets shows a reversal in the B isotope trend, with a decrease in δ11B from −8‰ to −14.1‰. This reversal cannot be explained by mineral-melt isotope fractionation, but requires fluid-melt partitioning and partial fluid loss. Hydrogen isotope variations in mica support this model. The systematic increase in δD from −75‰ in the outer zones (muscovite) to −63‰ and −53‰ in the inner zones (Li-micas) cannot be explained by closed-system variations in temperature or melt-mica fractionation, but it is consistent with late fluid exsolution. Oxygen isotope compositions of tourmaline (δ18O from 9.7‰ to 11.6‰), quartz (13.3‰ to 14‰) and mica (10.3‰ to 11.3‰) show good agreement with equilibrium partitioning and yield temperatures in the range 450°C to 600°C. Combining this with the stability fields of Li-aluminosilicates petalite and spodumene indicates crystallization pressures of 2–3kbar. Taken together, the stable isotope and mineral chemistry data demonstrate that rare-element enrichment in the innermost fractionated assemblages in the Varuträsk pegmatite was associated with the transition from purely magmatic crystallization to conditions where a separate aqueous fluid phase became important.