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The microwave waveguide and resonator methods are compared as applied to the experimental determination of the dielectric properties of high loss liquids. A differential microwave waveguide cavity for measuring high loss liquids complex permittivity in a small volume has been designed and studied. This cavity consists of two circular waveguide cells with central rods made of quartz and surrounded by high loss liquid tested. The cells have different lengths to eliminate complex propagation coefficient measurement errors due to the diffraction effect on the ends of the layered waveguide cells. We have measured the wave amplitude and phase coefficients for the waveguide cavity to estimate physical properties of a high loss liquid under test. The resonant frequencies and the Q-factor of a semi-disk dielectric resonator with high loss liquid filling a capillary have been measured. We have selected water-ethanol solutions as a high loss liquid under test for both techniques. We have determined the measurement sensitivity for these two techniques. The measuring results are discussed. Both the waveguide and resonator methods provide comparable sensitivity and can be successfully used for the complex permittivity characterization of high loss liquids in small volumes.
Areas of overlap between intensification in liquid–liquid systems and membrane technology intensification are highlighted. Liquid membrane systems, supported liquid membranes, pertraction, and application to liquid–liquid coalescence are discussed. Fundamentals of emulsion formation are reviewed, including thermodynamic aspects and the importance of emulsion properties for application. The role of surfactants in emulsion stability is discussed. Characterization of emulsions and predictive methods for emulsion drop size are described. The immobilization of solvents onto hollow fiber membranes is described and the advantages of low solvent inventory and ease of phase separation are highlighted. The basic principle of application of a liquid membrane system is described, showing the generic process steps: emulsification, contact with the feed phase, emulsion breakage, and product recovery. The role of facilitated transport is also described. Different configurations are compared, including hybrid liquid membranes, polymer inclusion membranes, and colloidal liquid aphrons. Selected examples of application of liquid membrane systems are described.
Ionic liquids are organic salts with potential for intensification of liquid–liquid processes. The structures of a range of significant ionic liquids are presented. The focus is on intensification of classical organic reactions and separations using ionic liquids in liquid–liquid systems. Their role as reaction media is briefly reviewed. Phase equilibrium properties of several liquid–liquid systems involving ionic liquids are described, demonstrating their potential for azeotrope breakage in vapor–liquid and liquid–liquid systems. Application of ionic liquid technology to phase-transfer catalysis is discussed, with inclusion of the classic example of the dimerization of butene to iso-octenes. The potential role of ionic liquids for the exploitation of biocatalytic processes is highlighted, with discussion of the potentially toxic effects on living biomass and on the activity of enzymes. The significance of the toxicity of some ionic liquids is summarized, together with a short discussion of potentially wider environmental impacts. The degradability of ionic liquids is an important part of environmental assessment that is also considered.
The principles of process intensification and the positive impacts for process safety, economics, and the exploitation of novel chemistry are described. The nexus between process intensification and sustainability is explained. The role of novel solvents such as ionic liquids in process intensification is discussed. The principles of liquid–liquid contact and phase separation are described, followed by a review of current engineering technologies for liquid–liquid processes which embrace the principles of process intensification. A brief overview of state-of-the-art mixing technology for liquid–liquid systems and for mixer settlers precedes a summary of current column contactor types and rotary contactors. Established designs of column contactors are briefly reviewed. The chapter includes some description of industrial coalescence equipment, showing how the design of coalescence equipment has been improved to enhance performance. A final section dealing with recent oscillatory baffled contactor technology is included, demonstrating how they meet the criteria for process intensification.
The performance of pigs is affected by the rate of nutrient absorption in the gastrointestinal tract, which depends in turn strongly on the rate of stomach emptying. The 13C breath test provides a non-invasive diagnostic tool to measure gastric emptying patterns. Despite the wide acceptance of this method in human intervention studies, it has not found its way to the domain of animal sciences. In this study, we used the breath test to measure gastric emptying in young growing pigs using [1-13C] octanoic acid to trace digesta solids and [1-13C] glycine to study liquids. Pigs were fed a starch-rich diet, varying in starch source (isolated starch from barley, maize or high-amylose maize) or form (isolated barley starch, ground barley or extruded barley), after which 13CO2 enrichment was frequently measured during 11 h. Outliers in 13CO2 enrichment in the response curve of each pig were identified with a Cookʼs distance outlier test in combination with a leave-one-out analysis. Effects of experimental treatments on breath test parameters were tested using a GLM. In general, pigs were easy to train and the tailor-made mask allowed effortless sampling. Gastric emptying of all pigs followed a biphasic pattern, with a higher 13C recovery during the first peak. The first peak in gastric emptying of solids reached its maximum enrichment within 2 h after feeding in all cases. For digesta liquids, this peak was reached earlier for pigs fed ground barley (2.2 h after feeding), compared to pigs fed diets containing isolated starch (2.8 h after feeding). The second peak in gastric emptying of solids was reached later for pigs fed ground barley (5.9 h after feeding), compared with pigs fed extruded barley (4.5 h after feeding) and pigs fed diets containing isolated barley starch (4.8 h after feeding). In conclusion, the 13C breath test is a convenient, non-invasive tool to gain more insights into the gastric emptying pattern of pigs.
Treats non-Fermi liquids and quantum critical points and describes Luttinger liquid theories. Bosonization of the noninteracting and interacting Tomonaga–Luttinger models are derived. Bosonization of the single particle operators is establshed and the corresponding Green functions derived.
Within the framework of the generalised Landau-de Gennes theory, we identify a Q-tensor-based energy that reduces to the four-constant Oseen–Frank energy when it is considered over orientable uniaxial nematic states. Although the commonly considered version of the Landau-de Gennes theory has an elastic contribution that is at most cubic in components of the Q-tensor and their derivatives, the alternative offered here is quartic in these variables. One clear advantage of our approach over the cubic theory is that the associated minimisation problem is well-posed for a significantly wider choice of elastic constants. In particular, this quartic energy can be used to model nematic-to-isotropic phase transitions for highly disparate elastic constants. In addition to proving well-posedness of the proposed version of the Landau-de Gennes theory, we establish a rigorous connection between this theory and its Oseen–Frank counterpart via a Г-convergence argument in the limit of vanishing nematic correlation length. We also prove strong convergence of the associated minimisers.
The chapter presents a theory of electron transport in graphene and discussion of the corresponding experimental data. We start with the discussion of quantum and classical Boltzmann equations and Kubo–Nakano–Moti formula for the electric resistivity. Further, we discuss the main extrinsic scattering mechanicsms relevant for the transport (charge impurities, resonant impurities, static ripples), and intrinsic mobility. For the latter, the role of two-phonon processes invloving flexural phonons is especially emphasized. We also consider edge scattering in graphene nanoribbons. Further, we discuss nonlocal electron transport, weak localization effects, and hydrodynamics of electron liquid in graphene.
Optical properties of massless Dirac electrons are considered. In particular, it is shown that they provide a universal, frequency-independent adsorption coefficient determined by fine structure constant. The possible effect of interelectron interaction on this property is discussed. Using a perturbation theory for density matrix, we derive Kubo formula for various response functions and use it to consider optics, magnetooptics, charge screening and diamagnetism of massless Dirac electrons. Graphene plasmonics is briefly reviewed.
Neuroblastoma is the most common extracranial solid tumour of infancy and accounts for about 6–10% of paediatric cancers. It has a biologically and clinically heterogeneous behaviour that ranges from spontaneous regression to cases of highly aggressive metastatic disease that could be unresponsive to standard therapy. In recent years, there have been several investigations into the development of various diagnostic, predictive and prognostic biomarkers towards personalised and targeted management of the disease.
Materials and Methods:
This paper reports on the review of current clinical and emerging biomarkers used in risk assessment, screening for early detection and diagnosis, prognostication and monitoring of the response of treatment of neuroblastoma in paediatric patients.
Tumour markers can significantly improve diagnosis; however, the invasive, unpleasant and inconvenient nature of current tissue biopsies limits their applications, especially in paediatric patients. Therefore, the development of a non-invasive, reliable high accurate and personalised diagnostic tool capable of early detection and rapid response is the most promising step towards advanced cancer management from tumour diagnosis, therapy to patient monitoring and represents an important step towards the promise of precision, personalised and targeted medicine. Liquid biopsy assay with wide ranges of clinical applications is emerging to hold incredible potential for advancing cancer treatment and has greater promise for diagnostic purposes, identification and tracking of tumour-specific alterations during the course of the disease and to guide therapeutic decisions.
The objective of this study was to explore the metabolic profiles of pregnancy malnutrition induced by feed restriction (FR) and the counteracting effects of glycerol and rumen-protected choline chloride supplementation. Two feeding trials were conducted. In the first experiment, twenty pregnant Hu sheep carrying multiple fetuses with a gestation period of 108 d were randomly divided into two groups. The ewes in the control (CON) group were offered 100 % of their nutritional requirements as recommended by the National Research Council (NRC), while the FR group was offered 30 % of feed intake of CON for 15 d. In the second experiment, eighteen pregnant Hu sheep were offered a feed intake comprising 30 % of the NRC-recommended nutritional requirements twice daily. The sheep were randomly divided into three groups: the FR group in the second experiment (FR2), with no supplementation, the glycerol (GLY) group, which received 40 ml of glycerol per d, and the rumen-protected choline chloride (RPC) group, which received 10 g of rumen-protected choline chloride per d for 9 d. In the first experiment, the urine metabolome of sixteen ewes showed significant difference between the CON group and FR group. Compared with the CON group, FR decreased the level of d-glucose, lactic acid, levoglucosan, α-ketoglutarate, phosphohydroxypyruvic acid, glucose 6-phosphate and the methyl donors, while increasing the level of pyruvate, fumaric acid and carnitines in urine. Both the GLY and RPC treatments counteracted some of these changes and modulated the urine metabolome in advanced pregnant ewes suffering from malnutrition.
When a liquid stream is injected into a gaseous atmosphere, it destabilizes and continuously passes through different states characterized by different morphologies. Throughout this process, the flow dynamics may be different depending on the region of the flow and the scales of the involved liquid structures. Exploring this multi-scale, multi-dimensional phenomenon requires some new theoretical tools, some of which need yet to be elaborated. Here, a new analytical framework is proposed on the basis of two-point statistical equations of the liquid volume fraction. This tool, which originates from single phase turbulence, allows us notably to decompose the fluxes of liquid in flow–position space and scale space. Direct numerical simulations of liquid–gas turbulence decaying in a triply periodic domain are then used to characterize the time and scale evolution of the liquid volume fraction. It is emphasized that two-point statistics of the liquid volume fraction depend explicitly on the geometrical properties of the liquid–gas interface and in particular its surface density. The stretch rate of the liquid–gas interface is further shown to be the equivalent for the liquid volume fraction (a non-diffusive scalar) of the scalar dissipation rate. Finally, a decomposition of the transport of liquid in scale space highlights that non-local interactions between non-adjacent scales play a significant role.
The interaction of a shock wave and a water droplet embedded with a vapour cavity is experimentally investigated in a shock tube for the first time. The vapour cavity inside the droplet is generated by decreasing the surrounding pressure to the saturation pressure, and an equilibrium between the liquid phase and the gas phase is obtained inside the droplet. Direct high-speed photography is adopted to capture the evolution of both the droplet and the vapour cavity. The formation of a transverse jet inside the droplet during the cavity-collapse stage is clearly observed. Soon afterwards, at the downstream pole of the droplet, a water jet penetrating into the surrounding air is observed during the cavity-expansion stage. The evolution of the droplet is strongly influenced by the evolution of the vapour cavity. The phase change process plays an important role in vapour cavity evolution. The effects of the relative size and eccentricity of the cavity on the movement and deformation of the droplet are presented quantitatively.
Green biorefineries provide novel opportunities to use the green biomass efficiently and utilize the ecosystem services provided by grasslands more widely. The effects of the inclusion of fractionated grass silage solid fraction (pulp) on feed intake, rumen fermentation, diet digestion and milk production in dairy cows were investigated. Pulp was separated from grass silage using a screw press simulating a green biorefinery. Partial removal of liquid from forage increased DM concentration from 220 to 432 g/kg and NDF from 589 to 709 g/kg DM while CP decreased from 144 to 107 g/kg DM. A feeding trial using an incomplete changeover design with 24 Nordic Red cows and two 3-week periods was conducted. The pulp replaced grass silage in the diet at 0 (P0), 25 (P25) and 50 (P50) percentage of total forage, which was fed ad libitum with 13 kg of concentrate for all treatments. The forage DM intake was highest on P25 (14.1 kg/day) while P0 and P50 did not differ from each other (13.2 and 13.0 kg/day, respectively). There were no differences between the treatments in rumen pH or ammonia N, but the proportion of acetate increased with increasing pulp inclusion. The digestibility was measured using acid insoluble ash and indigestible NDF (iNDF) as internal markers. Neither of the markers detected differences in NDF digestibility, but according to iNDF, apparent total tract organic matter digestibility decreased with increasing pulp inclusion. The cows maintained milk production at P25, but it showed some decline at P50 (energy-corrected milk at P0 and P25 was 39.8 kg/day while for P50, it was 38.5 kg/day, P = 0.056) and the milk protein yield significantly declined with higher pulp inclusion. Simultaneously, the nitrogen use efficiency in milk production increased. It seems that the fibrous grass-based fraction from a biorefinery process has potential to be used as a feed for ruminants.
The stability of forced planar liquid jets in a still gaseous environment is explored using nonlinear simulation and spatial linear stability analysis. Harmonic modulation of the transverse component of the inlet velocity leads to an excitation of sinuous modes in the jet. Two forcing amplitudes, 1 % and 5 %, are investigated. While for 1 % forcing, the interfacial disturbance retains a sinuous shape throughout the domain, for 5 % forcing, an increasing downstream deviation from the sinuous wave shape is found. Both forcings lead to sufficient mean flow correction to render linear stability analysis on a base flow unfeasible. Hence, an analysis on the time-averaged mean flow is performed. A correction scheme is introduced, to account for the spreading of the interface position in the mean flow. Comparison of eigenfunctions and growth rates with their counterparts from the nonlinear simulation shows an excellent agreement for 1 % forcing. For 5 % forcing, agreement of the eigenfunctions deteriorates significantly and growth rates are falsely predicted, resulting in a breakdown of the stability model. Subsequent analysis reveals a strong interaction of the fundamental wave with the second higher harmonic wave for 5 % forcing and a reversed energy flow from the coherent motion to the mean flow. These findings provide an explanation for the failure of the linear stability model for large forcing amplitudes. The study extends the applicability of mean flow stability analysis to convectively unstable planar liquid/gas jets and supports previous findings on the limits of mean flow stability, involving pronounced influence of higher harmonic modes.
Data from direct numerical simulations (DNS) of disperse bubbly flow in an upward vertical channel are used to develop a new second-moment closure for bubble-induced turbulence (BIT) in the Euler–Euler framework. The closure is an extension of a BIT model originally proposed by Ma et al. (Phys. Rev. Fluids, vol. 2, 2017, 034301) for two-equation eddy-viscosity models and focuses on the core region of the channel, where the interfacial term and dissipation term are in balance. Particular attention in this study is given to the treatment of the pressure–strain term for bubbly flows and the form of the interfacial term to account for BIT. For the latter, the concept of an effective BIT source is proposed, which leads to a significant simplification of the modelling work for both the pressure–strain correlation and the interfacial term itself. The anisotropy of bubbly flow is analysed with the aid of the anisotropy-invariant map obtained from the DNS data, and a parameter governing this issue is established. The complete second-moment closure is tested against reference data for different bubbly channel flows and a case of a bubble column. The agreement achieved with the DNS data is very good and the performance of the new model is better than obtained with the standard procedure. Furthermore, the model is shown to be robust and to fulfil the requirements of realizability.
The prediction of void fraction, which relies on interfacial force models, is a major issue in the context of boiling. The two-fluid model requires the modelling of the momentum transfer between phases. When bubbles are small (particle hypothesis), the momentum transfer is related to interfacial forces acting on bubbles. However, the splitting of these forces into drag, lift, added mass, etc., is not straightforward from the local point of view, where only the total interfacial force is defined as an integral of the constraint over the interface. For large-size bubbles, the particle hypothesis can be questioned. The momentum transfer can then be connected to the forces acting on a fluid element of the vapour phase. Based on the local and averaged formulations of the Navier–Stokes equations, a new balance equation for forces enables us to define lift, drag, added-mass and dispersion forces acting on a fluid element of the vapour phase. This equation gives a local definition for all the forces responsible for spatial distribution of bubbles and reflects the meaning usually assigned to the interfacial forces in the particle approach. Through this means, the link between the local formulation and physical phenomena is established and a new way of modelling the lift force is proposed. Furthermore, a new laminar dispersion force which relies on surface tension and pressure effects is introduced. The analysis of the budget equation on our direct numerical simulation database brings into light the large influence of this laminar dispersion force in the migration process. Different well-known physical behaviours can be modelled via this new force: the horizontal clustering of spherical bubbles in laminar flows and the oscillating trajectories of deformable bubbles.
Advanced glycation endproducts (AGE) are a group of complex and heterogeneous molecules, sharing some common characteristics such as covalent cross-link formation among proteins, the effect of transforming the colour of food products into yellow-brown colours and fluorescence formation. AGE are linked to many diseases including diabetes, renal diseases, CVD, liver diseases, neuro-degenerative and eye disorders, female reproductive dysfunction, and even cancer. AGE are formed endogenously but are also provided from exogenous sources including diet and tobacco. Western diet, rich in processed and/or heat-treated foods, fat and sugar, increases the exposure to AGE. The foods that contain high levels of fat and protein are generally rich in terms of AGE, and are also prone to AGE formation during cooking compared with carbohydrate-rich foods such as vegetables, fruits, legumes and whole grains. The present article aimed to review the literature about the effects of different cooking methods and conditions on the AGE content of food and AGE formation mechanisms using a comprehensive approach.
Although common beans (Phaseolus vulgaris L.) are consumed worldwide, studies on the metabolic fate of phenolic compounds from common beans are still very scarce. The present work aimed to study the bioavailability of phenolic compounds in human plasma and urine, after acute consumption of a single meal of cooked common beans. Blood and urine of seven volunteers were collected before (0 h) and at different time points (1, 2, 4, 6 and 8 h for plasma and 0–2, 2–4, 4–6, 6–8 and 8–24 h for urine) after beans’ intake. Ultra-high performance liquid chromatography-quadrupole-time of flight-MS (UPLC-Q-TOF-MS) was used for quantification. After beans’ intake, 405 (sd 3) g, containing 188 mg of phenolic compounds (expressed as gallic acid equivalents), there was a significant increase (P < 0·05) in the plasma concentration of six metabolites and in the urinary excretion of eleven metabolites. After 1 h post-consumption, metabolites, such as kaempferol-3-O-glucuronide, showed a significant increase in plasma concentration, suggesting kaempferol’s glucuronidation in the upper gastrointestinal tract. More than 50 % of the total amount of metabolites, such as 4-methylcatechol-O-sulphate and dihydrocaffeic acid-3-O-sulphate, were excreted after 8 h post-consumption, indicating colonic bacterial metabolism of the phenolic compounds. Partial least square-discriminant analysis models clearly showed clusters of metabolites, which contributed to extend the list of compounds related to cooked common beans’ human intake at different time points and showed the human inter-individual variability in plasma concentration as well as in urinary excreted metabolites, after cooked common beans’ intake.
The experimental study on thermocapillary convection in liquid bridges of large Prandtl number has been carried out on Tiangong-2 in space. The purpose of these experiments is to study the oscillation instability of thermocapillary convection, and to discover and recognize the mechanism of destabilization of thermocapillary convection in the microgravity environment in space. In this paper, the geometry of a half-floating-zone liquid bridge is featured by the aspect ratio Ar and volume ratio Vr, and its influence on critical conditions of oscillatory thermocapillary convection is studied. More than 700 sets of space experiments have been finished. The critical conditions and oscillation characteristics of thermocapillary convection instability in the Ar–Vr parameter space have been fully obtained under microgravity conditions for the first time. It is found that the Ar–Vr parameter space can be divided into two regions of different critical conditions and oscillation characteristics: the region of low frequency oscillation, and the region of high frequency oscillation. More importantly, we obtain the complete configuration of these two stability neutral curves, and find that the low frequency mode is a ‘’ type curve. Based on this, we discuss the influence of heating rate on the oscillation mode. It is found that the heating rate affects the selection of critical mode, which results in a jump change of critical temperature difference. The findings of this study are helpful to better understand the critical modes and transition processes of thermocapillary convection in liquid bridges with different configurations.