Dynamics of double emulsion break-up in three phase glass capillary microfluidic devices

Pinch-off of a compound jet in 3D glass capillary microfluidic device, which combines co-flowing and countercurrent flow focusing geometries, was investigated using an incompressible three-phase axisymmetric Volume of Fluid–Continuum Surface Force (VOF–CSF) numerical model. The model showed good agreement with the experimental drop generation and was capable of predicting formation of core/shell droplets in dripping, narrowing jetting and widening jetting regimes. In dripping and widening jetting regimes, the presence of a vortex flow around the upstream end of the necking thread facilitates the jet break-up. No vortex flow was observed in narrowing jetting regime and pinch-off occurred due to higher velocity at the downstream end of the coaxial thread compared to that at the upstream end. In all regimes, the inner jet ruptured before the outer jet, preventing a leakage of the inner drop into the outer fluid. The necking region moves at the maximum speed in the narrowing jetting regime, due to the highest level of shear at the outer surface of the thread. However, in widening jetting regime, the neck travels the longest distance downstream before it breaks

Double emulsion production in glass capillary microfluidic device: Parametric investigation of droplet generation behaviour

A three-phase axisymmetric numerical model based on Volume of Fluid–Continuum Surface Force (VOF–CSF) model was developed to perform parametric analysis of compound droplet production in three-phase glass capillary devices that combine co-flow and countercurrent flow focusing. The model predicted successfully generation of core–shell and multi-cored double emulsion droplets in dripping and jetting (narrowing and widening) regime and was used to investigate the effects of phase flow rates, fluid properties, and geometry on the size, morphology, and production rate of droplets. As the outer fluid flow rate increased, the size of compound droplets was reduced until a dripping-to-jetting transition occurred. By increasing the middle fluid flow rate, the size of compound droplets increased, which led to a widening jetting regime. The jetting was supressed by increasing the orifice size in the collection capillary or increasing the interfacial tension at the outer interface up to 0.06 N/m. The experimental and simulation results can be used to encapsulate CO2 solvents within gas-permeable microcapsules

A new formalism for the estimation of the CP-violation parameters

In this paper, we use the time super-operator formalism in the 2-level Friedrichs model \cite{fried} to obtain a phenomenological model of mesons decay. Our approach provides a fairly good estimation of the CP symmetry violation parameter in the case of K, B and D mesons. We also propose a crucial test aimed at discriminating between the standard approach and the time super-operator approach developed throughout the paper

Production of spherical mesoporous molecularly imprinted polymer particles containing tunable amine decorated nanocavities with CO2 molecule recognition properties

Novel spherical molecularly imprinted polymer (MIP) particles containing amide-decorated nanocavities with CO2 recognition properties in the poly[acrylamide-co-(ethyleneglycol dimethacrylate)] mesoporous matrix were synthesized by suspension polymerization using oxalic acid and acetonitrile/toluene as dummy template and porogen mixture, respectively. The particles had a maximum BET surface area, SBET, of 457 m2/g and a total mesopore volume of 0.92 cm3/g created by phase separation between the copolymer and porogenic solvents. The total volume of the micropores (d < 2 nm) was 0.1 cm3/g with two sharp peaks at 0.84 and 0.85 nm that have not been detected in non-imprinted polymer material. The degradation temperature at 5% weight loss was 240–255 °C and the maximum equilibrium CO2 adsorption capacity was 0.56 and 0.62 mmol/g at 40 and 25 °C, respectively, and 0.15 bar CO2 partial pressure. The CO2 adsorption capacity was mainly affected by the density of CO2-philic NH2 groups in the polymer network and the number of nanocavities. Increasing the content of low-polar solvent (toluene) in the organic phase prior to polymerization led to higher CO2 capture capacity due to stronger hydrogen bonds between the template and the monomer during complex formation. Under the same conditions, molecularly imprinted particles showed much higher CO2 capture capacity compared to their non-imprinted counterparts. The volume median diameter (73–211 μm) and density (1.3 g/cm3) of the produced particles were within the range suitable for CO2 capture in fixed and fluidized bed systems

Throughfall Nutrients in a Degraded Indigenous Fagus Orientalis Forest and a Picea Abies Plantation in the of North of Iran

Aim of study: The objective of this study was to compare the quantity and quality of TF (throughfall) in an indigenous, but degraded, stand of Fagus orientalis and Picea abies plantation. Area of study: Forests of Kelar-Dasht region located in Mazandaran province, northern Iran. Material and Methods: TF measured by twenty collectors that were distributed randomly underneath each stand. For 21 storms sampled in 2012 (August-December) and 2013 (April-June), we analyzed pH, EC, Ca2+, Mg2+, K+, NO3-, and P of gross rainfall (GR) and TF. Main results: Cumulative interception (I) for F. orientalis and P. abies were 114.2 mm and 194.8 mm of the total GR, respectively. The amount of K+ (13.4 mg L-1) and Ca2+ (0.9 mg L-1) were higher (for both elements, p = 0.001) in the TF of P. abies compared to those of F. orientalis (6.8 and 0.5, mg L-1, respectively) and GR (3.2 and 0.37 mg L-1, respectively). Conversely, mean P concentration was doubled (p = 0.022) in the TF of F. orientalis (11.1 mg L-1) compared to GR (5.8 mg L-1). Research highlights: P. abies plantations may provide a solution for reforestation of degraded F. orientalis forests of northern Iran, yet how P. abies plantations differentially affect the quality and quantity of rainfall reaching subcanopy soils (TF) compared to F. orientalis is unknown. Understanding the connection between hydrological processes and nutrient cycling in forest ecosystems is crucial for choosing the appropriate species to rehabilitate the degraded indigenous forests with nonindigenous species

DOCUMENTATION AND SIGNIFICANCE OF TECTONIC EVENTS IN THE NORTHERN TABAS BLOCK (EAST-CENTRAL IRAN) DURING THE MIDDLE AND LATE JURASSIC

Apart from global sea-level fluctuations, the sedimentary pattern of the northern Tabas Block during the Middle and Late Jurassic was mainly governed by tectonic events of varying intensity and areal extent. These events took place during the Middle Bajocian (mid-Cimmerian tectonic phase), Early Bathonian, Late Bathonian, Early Callovian, Late Oxfordian, and Late Kimmeridgian. The importance and extent of each event and its influence on the facies pattern of the northern Tabas Block is briefly discussed and demostrated by some examples

Mechanisms and control of single-step microfluidic generation of multi-core double emulsion droplets

Single-step generation of monodisperse multi-core double emulsion drops in three-phase glass capillary microfluidic device was investigated using a micro-particle image velocimetry (micro-PIV) system. Phase diagrams were developed to predict the number of encapsulated inner drops as a function of the capillary numbers of inner, middle and outer fluid. The maximum stable number of inner drops cores in uniform double emulsion drops was six. Starting from core/shell drops, the formation of double emulsion drops with multiple cores was achieved by decreasing the capillary number of the outer fluid and increasing the capillary number of the middle fluid. A stable continuous jet of the middle fluid loaded with inner drops was formed at high capillary numbers of the middle fluid. Empirical correlations predicting the size and generation frequency of inner drops as a function of the capillary numbers and the device geometry were developed. Dual-core double emulsion drops were used as templates for the fabrication of polymeric capsules using “on-the-fly” photopolymerisation. The capsule morphology was controlled by manipulating the stability of the inner drops through adjusting the concentration of the lipophilic surfactant in the middle fluid. At low concentration of the lipophilic surfactant, inner drop coalesced during curing and single compartment capsules with thin shells were produced from dual-core drops. The core/shell capsules produced from multi-core drops were monodispersed and larger than those produced from core/shell drops in the same device

A summary of the Jurassic System in North and East-Central Iran

The rocks of the Jurassic System in North and Central Iran are represented by very thick sedimentary successions reflecting the deposition during two tectono-stratigraphic megacycles, bounded by three important unconformities. The older (Early to early Middle Jurassic) cycle starts, after the Late Triassic closure of the Palaeotethys and the collision of the Iran Plate with the southern margin of Eurasia (Turan Plate), with an abrupt uplift of the Cimmerian Mountains around the Triassic–Jurassic boundary (Main-Cimmerian Event) and is terminated by the Mid-Cimmerian Tectonic Event in the mid-Bajocian. The predominantly siliciclastic sediments of this tectono-stratigraphic cycle are accommodated in the Ab-e-Haji Subgroup of the (upper) Shemshak Group. The Ab-e-Haji Subgroup consists of thick and widespread, partly coal-bearing siliciclastic strata and also records some important marine ingressions, especially in the Toarcian and Aalenian. The younger tectono-stratigraphic cycle starts with an extensive marine transgression in the Late Bajocian and ends around the Jurassic-Cretaceous boundary with the Late Cimmerian Tectonic Event. In the aftermath of the Mid-Cimmerian Tectonic Event, the Iran Plate was dissected into several structural units, the geological histories of which differed and so did their facies patterns. Thus, in North Iran two main sedimentary areas developed, namely the Alborz and Koppeh Dagh basins, which show moderate diffe-rences in lithology and thicknesses. However, the differentiation is much more pronounced on the Central-East Iranian Microcontinent, which comprises three N–S-oriented and independent structural units, i.e., from east to west the Lut, Tabas and Yazd blocks. During the Jurassic Period, the sea mostly covered the Tabas and Lut blocks, whereas the Yazd Block remained largely emergent. The lithologically diverse and numerous formations of the area are combined in the Magu and Bidou groups. Early to Early Middle Jurassic ammonite fau-nas of North and Central Iran are palaeobiogeographically closely related to Northwest European (Subboreal) ammonite faunas, allowing a similar biozonation. Concurrent with the Late Bajocian transgression, there is an abrupt change in faunal composition and the Middle and Late Jurassic ammonite faunas of North and Central Iran are much more similar to those of epicontinental seas bordering the nort-hern margin of the western Tethys and occupy an intermediate position between the Mediterranean and the Submediterranean Province. The results of the studies on ammonoid palaeobiogeography are in line with Early Jurassic palaeogeographic reconstructions that place the Iran Plate at fairly high palaeo-latitudes of about 45°N, followed by a rapid southward shift throughout the Middle and Late Jurassic to a position of about 30°N