Search

Aluminum/tetrahydrodicyclopentadiene/oleic acid (Al/JP-10/OA) nanofluid fuel is considered a potential fuel for aircraft powered by aviation turbine engines. However, an optimized formula for an Al/JP-10/OA system inducing a secondary atomization and micro-explosion effect and improving the burning performance needs to be developed. With this aim, in this work, the combustion characteristics of pure JP-10, JP-10/OA, JP-10/Al, and Al/JP-10/OA were experimentally tested, and a comparative analysis was conducted. Specifically, the influence of the surfactant and nanoparticle concentrations on the combustion characteristics of Al/JP-10/OA nanofluid fuel, including the flame structure, the flame temperature, the burning rate, the secondary atomization and micro-explosion effect, etc., were evaluated in detail. The results demonstrate that the addition of OA surfactant and Al nanoparticles had a significant effect on the burning rate of fuel droplets. The OA had an inhibition effect, while the Al nanoparticles had a promotion effect. As both OA and Al nanoparticles were added to the JP-10, the synergetic effect had to be considered. At the optimum ratio of OA to Al for the best suspension stability, there is a critical Al concentration of 1.0 wt.% from promotion to inhibition with increases in the Al concentration. The addition of OA and Al nanoparticles induced the secondary atomization and micro-explosion, resulting in an unsteady combustion and chaotic flame structure. The transient flame temperature of hundreds of Kelvins increased, the high-temperature flame zone widened, and thus, the energy release was elevated. Therefore, the combustion performance and energy release of Al/JP-10/OA nanofluid fuel can be improved through the secondary atomization and micro-explosion effect induced by the surfactant and nanoparticles. [ABSTRACT FROM AUTHOR]

Conjugated polymers have attracted extensive attention in numerous research fields because of their exceptional photoelectric properties and distinctive solution processing capabilities. The conformation of the chain and the structure of the condensed state in solution are closely related to various factors, such as concentration and solvent. Concentration, as a significant external parameter, plays a crucial role in the self‐assembly and formation of crystalline structures in conjugated polymers. It also affects the properties of the solution, the structure of the membrane, and the performance of the fabricated devices. Recently, there have been an increasing number of studies conducted from the perspective of solution concentration. Therefore, it is important to comprehensively summarize the effect of concentration on the transition process of chain structure from solution to film, as well as the impact of concentration on the performance of related devices. In this review, we summarize the effects of concentration on the chain motion, particle size, ordered structure, and photoelectric properties of conjugated polymers in solutions and thin films, as well as on device efficiency. This provides a unique perspective on the fundamental characteristics of conjugated polymers, which can assist in the development and improvement of optoelectronic devices. [ABSTRACT FROM AUTHOR]

This work involves an experimental study of the thermophysical properties of hybrid nanofluids of TiO2 and graphene in a binary mixture of water and ethylene glycol. Hybrid nanofluid samples with different volume fractions (0.05-2.5%) were prepared by dispersing equal volumes of TiO2 and graphene nanoparticles in a binary mixture of water and ethylene glycol in the ratio of 50-50% by volume. The thermal conductivity, surface tension, and dynamic viscosity of the hybrid nanofluids were measured at temperatures ranging from 253 K to 303 K. The experimental results showed that the low concentration samples exhibited shear thinning non-Newtonian behavior, while the high concentration samples exhibited shear thickening non-Newtonian behavior. The measurements showed that the thermal conductivity of the nanofluids increases by up to 41.93% with increasing nanoparticle concentration and temperature. The surface tension improves by 43.61%, 39.77%, and 51.98% at concentrations of 2.5%, 2%, and 2% by volume at temperatures of 258.15 K, 268.15 K, and 283.15 K, respectively. In terms of aircraft deicing fluid performance, the addition of TiO2 and graphene nanoparticles at less than 0.5% by volume contributes to the improvement of aircraft deicing fluid performance.

The phase state, electrical conductivity and magnetoresistive properties of binary film alloys based on Fe, Co and Ni prepared by the method evaporation in high vacuum in the temperature range 100700 K have been studied. It has been shown that the fcc-phase is observed for as-deposited and annealed up to 700 K Fe0,50Ni0,50 thin films with a thickness d 10100 nm, the fcc-phase is observed. For Fe0,67Ni0,33 Fe0,50Co0,50 and Fe0,67Co0,33 thin films, the bcc-phase is fixed. It was found that the size dependences of the resistivity, temperature coefficient of resistance and magnetoresistance are realized for all structurally continuous film alloys. The character of size dependences is а like the corresponding dependences for the pure metal films. It has been shown that for Fe0,67Ni0,33, Fe0,50Co0,50 and Fe0,67Co0,33 the size dependences of both longitudinal and transverse magnetoresistance appear much weaker than for Fe0,50Ni0,50 thin alloy. For Fe0,67Ni0,33, Fe0,50Co0,50 and Fe0,67Co0,33 thin alloys, the value of both longitudinal and transverse magnetoresistance is weakly depending on the temperature. [ABSTRACT FROM AUTHOR]

[Display omitted] • The catalytic effect of bismuth on Pt(1 0 0) electrodes for the FAOR is linked to the Pt-Bi ensembles. • Bismuth catalyzes the direct path and inhibits the CO formation route. • A mechanism for the reaction that accounts for the experimental results is proposed. The formic acid oxidation reaction (FAOR) on bismuth-modified Pt(1 0 0) is studied using electrochemical techniques and FITR spectroscopy at different bismuth coverages and formic acid concentrations. The results clearly show that: (1) The measured currents for the Bi-modified Pt(1 0 0) surface contain contributions from both the Pt-Bi ensembles and the Pt sites far from the Bi adatoms. (2) The catalytic effect of bismuth is not linked to the adsorption of formate on Pt sites. (3) The bismuth not only improves the activity of the FAOR through the active intermediate but also inhibits the CO poison by a third-body effect. (4) The experimental results indicate that the catalytic activity is linked to the Pt-Bi ensembles. The active species, formate, adsorbs on the Bi site and the neighboring Pt sites facilitate the cleavage of the C–H bond. (5) From the concentration dependence, the reaction order for formate on bismuth-modified Pt(1 0 0) is 1 at low potentials. In contrast, a reaction order of 0.5 is obtained at higher potentials. These results are in agreement with the proposed mechanism. [ABSTRACT FROM AUTHOR]

Aluminum/tetrahydrodicyclopentadiene/oleic acid (Al/JP-10/OA) nanofluid fuel is considered a potential fuel for aircraft powered by aviation turbine engines. However, an optimized formula for an Al/JP-10/OA system inducing a secondary atomization and micro-explosion effect and improving the burning performance needs to be developed. With this aim, in this work, the combustion characteristics of pure JP-10, JP-10/OA, JP-10/Al, and Al/JP-10/OA were experimentally tested, and a comparative analysis was conducted. Specifically, the influence of the surfactant and nanoparticle concentrations on the combustion characteristics of Al/JP-10/OA nanofluid fuel, including the flame structure, the flame temperature, the burning rate, the secondary atomization and micro-explosion effect, etc., were evaluated in detail. The results demonstrate that the addition of OA surfactant and Al nanoparticles had a significant effect on the burning rate of fuel droplets. The OA had an inhibition effect, while the Al nanoparticles had a promotion effect. As both OA and Al nanoparticles were added to the JP-10, the synergetic effect had to be considered. At the optimum ratio of OA to Al for the best suspension stability, there is a critical Al concentration of 1.0 wt.% from promotion to inhibition with increases in the Al concentration. The addition of OA and Al nanoparticles induced the secondary atomization and micro-explosion, resulting in an unsteady combustion and chaotic flame structure. The transient flame temperature of hundreds of Kelvins increased, the high-temperature flame zone widened, and thus, the energy release was elevated. Therefore, the combustion performance and energy release of Al/JP-10/OA nanofluid fuel can be improved through the secondary atomization and micro-explosion effect induced by the surfactant and nanoparticles.

This work involves an experimental study of the thermophysical properties of hybrid nanofluids of TiO2 and graphene in a binary mixture of water and ethylene glycol. Hybrid nanofluid samples with different volume fractions (0.05-2.5%) were prepared by dispersing equal volumes of TiO2 and graphene nanoparticles in a binary mixture of water and ethylene glycol in the ratio of 50-50% by volume. The thermal conductivity, surface tension, and dynamic viscosity of the hybrid nanofluids were measured at temperatures ranging from 253 K to 303 K. The experimental results showed that the low concentration samples exhibited shear thinning non-Newtonian behavior, while the high concentration samples exhibited shear thickening non-Newtonian behavior. The measurements showed that the thermal conductivity of the nanofluids increases by up to 41.93% with increasing nanoparticle concentration and temperature. The surface tension improves by 43.61%, 39.77%, and 51.98% at concentrations of 2.5%, 2%, and 2% by volume at temperatures of 258.15 K, 268.15 K, and 283.15 K, respectively. In terms of aircraft deicing fluid performance, the addition of TiO2 and graphene nanoparticles at less than 0.5% by volume contributes to the improvement of aircraft deicing fluid performance. [ABSTRACT FROM AUTHOR]

We review and analyse the literature data on the experimental results dealing with the crystal structure, phase state, and magnetoresistive properties of nanostructured thin-film systems based on NixFe1–x permalloy and noble metals prepared by the methods of co-evaporation and layer-by-layer condensation. As shown, regardless of preparation methods, the phase state of systems stays as two-phase one. Upon high-temperature annealing, the formation of solid solutions is possible. As shown, in the case of applying of layer-by-layer condensation method, the value of the magnetoresistive effect depends on the thickness of the magnetic and nonmagnetic layers. In the case of applying the co-evaporation method, the determining parameters are the concentrations of the components and the total thickness of the system. The annealing-temperature effect on magnetoresistive properties of nanostructured thin-film systems based on permalloy and noble metals is analysed.

With the emergence of new psychoactive substances (NPSs) over the years, the substances detected on stamps (also known as blotter papers) have also evolved from the traditional drug—lysergic acid diethylamide (LSD) to the multiple variants of lysergamides such as ALD‐52 and 1P‐LSD. The analysis of such blotter papers is usually done by solvent extraction followed by identification using gas chromatography–mass spectrometry (GC‐MS). This study has shown that hydrolysis to form LSD was observed in GC‐MS analysis when ALD‐52 was extracted with methanol. The extraction of ALD‐52 using other solvents such as acetonitrile, ethanol, isopropyl alcohol, ethyl acetate, and acetone, followed by GC‐MS analysis, was investigated. It is shown that alcoholic solvents such as methanol and ethanol will result in the conversion of ALD‐52 to LSD during GC‐MS analysis, whereas the sterically hindered isopropyl alcohol will prevent this conversion. Investigation also shows that the hydrolysis of ALD‐52 to LSD occurs at the GC injector port. It was also observed that the degree of hydrolysis was more pronounced at a lower concentration (0.1 mg/mL). The study was extended to a close analog—1P‐LSD, and the results showed that 1P‐LSD similarly hydrolyzes to LSD. However, 1P‐LSD was observed to be more stable than ALD‐52 due to steric hindrance because of the propanoyl group. [ABSTRACT FROM AUTHOR]

This study provides an overview of Building-Integrated Wind Turbines, focusing on cement silos as wind concentrators, along with determining the amount of power that could be connected without regard to wind direction. The motivation of this research is the intermittency issue of wind stream in an open environment and non-exploration of wind turbines between cement silos. Building-Augmented Wind Turbines provide 717 W of aerodynamic power at 16 m/s, whereas Standalone Wind Turbines produce 562 W. This is due to the wind speed acceleration between buildings, which causes a concentration effect. Meanwhile, using the simulation software ANSYS, the turbine geometry is developed utilising a Computational Fluid Dynamics evaluation. [ABSTRACT FROM AUTHOR]

In this study, the complexity of sodium ascorbate as a reducing reagent for copper by executing reactions with different ascorbate concentrations at 30°C and a copper concentration at 5 mM was emphasized. It was found that increasing the molar ratio of nascorbate/nCu2+ from 1:1 to 10:1 prolonged the time for the completion of the reduction from 30 to 300 min, respectively. The reactions were investigated by the cyclic voltammetry method and the products were characterized by scanning electron microscopy and X-ray diffraction analyses. The synthesized materials obtained with molar ratios of 1:1 and 10:1 were composed of 55.47% Cu + 44.53% Cu2 O (labeled as As1) and 73.66% Cu + 26.34% Cu2 O (labeled as As10), respectively. Both products were tested for their ability to discolor Basic Red 29 via the Fenton reaction. The discoloration of the dye was more rapid with As1, due to the higher Cu2 O content. [ABSTRACT FROM AUTHOR]

Alpha(α)‐synuclein is closely related to the pathogenesis of Parkinson's disease (PD). The NACore, a fragment of α‐synuclein, is considered to be the key region of α‐synuclein that causes PD. The aggregation dynamics of NACores are studied via coarse‐grained molecular dynamics simulations. We find that NACores can self‐assemble into a large cluster at high concentrations. The aggregation dynamics can be divided into three stages. The growth kinetics for the first and second stages follows the power law, Smax ~ tγ, with the second stage faster than the first one. The characteristic lifetime for the high concentration is 40 times larger than that for the low concentration, implying the low fluidity. Understanding the aggregation dynamics of NACores is helpful to develop drugs for therapeutic prevention and intervention. [ABSTRACT FROM AUTHOR]

In the preparation of polyammonium resin by polycondensation of equimolar amounts of epichlorohydrin and 1,3-bis(dimethylamino)propanol-2 in aqueous solutions, a nonstandard concentration effect was revealed, which manifested itself in a sharp increase in the reduced reaction rate, equilibrium conversion, and achievable molecular weight of the polymer at initial concentrations of reagents close to 2.0 mmol/g (the concentration range of 0.5–3.5 mmol/g was studied). The data obtained can be used in the search for additional economical resources to improve the technical and economic indicators of organic synthesis processes. [ABSTRACT FROM AUTHOR]

This work investigated the photoluminescence behaviour of Tb3+ doped BiPO4 nanophosphors synthesised by co-precipitation method using ethylene glycol. The prepared nanophosphors were characterised by XRD, SEM, FT-IR and PL spectroscopy techniques. Monoclinic phase was observed from the XRD and FT-IR studies. SEM image showed agglomeration of nanoparticles. In the emission spectra, band originated from 3P1–1S0 transition of Bi3+ ion and bands due to 5D4 → 7F6,5,4,3 transitions of doping Tb3+ ion were observed upon excitation at 351 nm. The emission intensity was found to accentuate with the increase in Tb3+ ion concentration upto 3at. % and subsequently attenuated with further increase in Tb3+ ion concentration due to concentration quenching effect. The decay time of the prepared phosphors was also investigated. The CIE chromaticity diagram revealed a nearly white colour emission upon excited at 351 nm. It is possible that the prepared phosphors may be useful for solid-state lighting. [ABSTRACT FROM AUTHOR]

Utilization of Ti 3 C 2 nanosheets for enhancing anticorrosion of epoxy resin coatings has been reported. But the epoxy coatings in real world are mainly pigmented coatings. Unfortunately, the anticorrosion behavior of Ti 3 C 2 nanosheets for the pigmented epoxy coatings is rarely concerned. In this work, both 0.5 wt% unmodified Ti 3 C 2 nanosheets (U-Ti 3 C 2) or 0.5 wt% (3-glycidyloxypropyl)trimethoxysilane-modified Ti 3 C 2 nanosheets (G-Ti 3 C 2) were introduced into solvent-based titania pigmented epoxy coatings. Corrosion resistance of coatings was evaluated by electrochemical impedance spectroscopy and salt spray tests. A titania concentration effect was interestingly exhibited for the anticorrosion behavior Ti 3 C 2 -containing pigmented coatings. Enhanced anticorrosion was only demonstrated when TiO 2 content was not above 10 wt% for U-Ti 3 C 2 or 5 wt% for G-Ti 3 C 2. Moreover, the pigmented coatings with U-Ti 3 C 2 have better corrosion resistance than those with G-Ti 3 C 2 , being contrary to the phenomenon observed in pure epoxy resin coatings. The different anticorrosion behavior of Ti 3 C 2 nanosheets for epoxy coatings with various TiO 2 contents was mainly attributed to the different dispersion states of TiO 2 pigments, that is, improved dispersion at low TiO 2 content and deteriorated dispersion at high TiO 2 content, after addition of Ti 3 C 2 nanosheets. [Display omitted] • A titania concentration effect was exhibited for the anticorrosion performance Ti 3 C 2 -containing pigmented coatings. • Titania dispersion was improved by Ti 3 C 2 at low titania content. • Deteriorated titania dispersion by Ti 3 C 2 was found at high titania content. • Pristine Ti 3 C 2 causes better corrosion resistance than GPS modified one. • The coating with 5 % TiO 2 and 0.5 % Ti 3 C 2 showed impedance modulus of 1.03 × 1011 Ω․cm2. [ABSTRACT FROM AUTHOR]

Veterinary antibiotics are increasingly used in the livestock industry annually. Sulfonamides introduced into the soil with manure are usually largely degraded in various pathways. However, the influence of the metabolic intermediate of sulfonamides on nitrogen (N) cycling under anaerobic conditions in soils has been overlooked. To this end, we carried out a microcosm experiment to investigate the potential consequences of ADPD (2-amino-4,6-dimethylpyrimidine, a degradation product of sulfonamide) at five concentration gradients (i.e., 0, 0.01, 0.1, 1, and 10 mg kg−1) on nitrous oxide (N 2 O) emissions, associated genes involved in N cycling, antibiotic resistance genes (ARGs), and mobile genetic elements (MGEs) in soils applied with manure or urea. The results showed that ADPD application promoted N 2 O emissions under flooded conditions at environmentally relevant concentrations, and the maximum cumulative N 2 O emissions were observed at 1 mg kg−1 and 0.1 mg kg−1 ADPD for manure and urea applied, respectively. The main reasons were the imbalance of denitrifying bacteria, which affected N 2 O production and reduction, and the increase of antibiotic resistance in soil bacteria. In conclusion, these findings contribute to assessing the eco-environmental risks associated with the prevalence of sulfonamide metabolic intermediates and expand our understanding of the link between antibiotics and N transformation. Further research in the field is warranted to incorporate their recommendations into the greenhouse gas assessment system. [Display omitted] [ABSTRACT FROM AUTHOR]

Hydrogen peroxide (H2O2) can be considered as a sterilant or a green propellant. For a common use in industrial application, spray is an effective method to form fine H2O2 droplets. In this paper, electrostatic atomization based on the configuration of needle ring electrodes is proposed to produce H2O2 spray by minimizing its effective surface tension. The breakup performances of H2O2 ligaments can be improved by increasing the electric field intensity, reducing the nozzle size, and adjusting suitable volume flow rate. The smallest average diameter of breakup droplets for 35 wt. % concentration H2O2 solution reached 92.8 μm under optimum operation conditions. The H2O2 concentration significantly influenced the breakup performance owing to the concentration effect on comprehensive physical properties such as density, surface tension, viscosity, and permittivity. The average diameters of breakup droplets decreased with decreasing H2O2 concentration. At 8 wt. % concentration, the average breakup droplet diameter was reduced to 67.4 μm. Finally, electrostatic atomization mechanism of H2O2 solution was analyzed by calculating dimensionless parameters of Re, We, and Oh numbers with the combination of the operation conditions and physical properties for in-depth understanding the breakup behaviors. The calculation showed that the minimum average diameter of breakup droplets was obtained at 8 wt. % concentration at the investigated range of H2O2 concentration, which kept in agreement with the experimental results. [ABSTRACT FROM AUTHOR]

Simple Summary: The number of insects that feed on an individual tree can be influenced by the growth of leaves during the season, the size of the tree, genetic traits that affect leaf quality, and by the tree species that surround it. To estimate the relative importance of these processes, we determined the date on which leaves start unfolding in spring, trunk diameter, genotype, and neighbourhood of sessile oak trees, and sampled their caterpillar communities. We found that free-living caterpillars were less abundant on older leaves. Caterpillars were less diverse and experienced higher parasitism on larger trees. Leaf-mining casebearers were more abundant on trees that were genetically more homozygous. However, genome size was not important for any guild. In contrast to most previous studies, oaks surrounded by distantly related tree species tended to have higher caterpillar densities. Neighbourhoods were also related to species composition and diversity, but not to the average wingspans or specialization of species. Common species were less abundant on trees with high parasitism rates. Our results suggest that trees are not always better off in diverse forests, as large trees surrounded by distantly related species might actually suffer more insect damage. Communities of herbivorous insects on individual host trees may be driven by processes ranging from ongoing development via recent microevolution to ancient phylogeny, but the relative importance of these processes and whether they operate via trophic interactions or herbivore movement remains unknown. We determined the leaf phenology, trunk diameter, genotype, and neighbourhood of sessile oak trees (Quercus petraea), and sampled their caterpillar communities. We found that leaf development across a time period of days related to free-living caterpillars, which disappeared with leaf age. Tree growth across decades is related to increased parasitism rate and diversity of herbivores. The microevolution of oak trees across millennia is related to the abundance of leaf-mining casebearers, which is higher on more homozygous oaks. However, oak genome size was not important for any guild. In contrast to most previous studies, the phylogenetic distance of oaks from their neighbours measured in millions of years was associated with higher abundances of entire caterpillar guilds. Furthermore, on trees surrounded by only distantly related tree species, parasitism tended to be lower. Lower parasitism, in turn, was associated with higher abundances of codominant caterpillar species. Neighbourhoods and traits of trees were also related to community composition and diversity, but not to the average wingspans or specialization of species, consistent with the assembly of herbivore communities being driven by leaf traits and parasitism pressure on trees rather than by insect movement among trees. However, movement in rarer species may be responsible for concentration effects in more phylogenetically distant neighbourhoods. Overall, we suggest that the assembly of insects on a tree is mostly driven by trophic interactions controlled by a mosaic of processes playing out over very different time scales. Comparisons with the literature further suggest that, for oak trees, the consequences of growing amongst distantly related tree species may depend on factors such as geographic region and tree age. [ABSTRACT FROM AUTHOR]

Bottom-up construction of highly complex architecture from simple components remains one of the long-standing challenges in chemistry. Herein two supramolecular isomers based on large trigonal prismatic Pd3L16 building block are reported. Significantly, they can be controllably obtained by adjusting the solute concentration during crystal growth. Specifically, the square shape crystals, α-[Pd3L16](PF6)12 in the cubic system with I 4 ¯ 3 m space group, can be isolated from a high-concentration solution of Pd3L16. Interestingly, a mesoporous cage assembled from eight Pd3L16 units with a diameter of 24 Å is observed in the crystal structure. For the low-concentration solution of Pd3L16, the rectangular shape crystals β-[Pd3L16](PF6)12 are obtained, which crystallize in the hexagonal system with P63Im space group, and display two-dimension packing pattern and one-dimension mesoporous channels (diameter ca. 22 Å) along the c axis. Moreover, the two supramolecular isomers were used as nanoporous reactors to induce the specific formation of polyiodides with different compositions and shapes as evidenced from single crystal X-ray diffraction studies. These findings provide a reference in targeting functional crystalline mesoporous supramolecular materials from a single complex building unit. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Hydrobiology is the property of Editorial Department of Journal of Hydrobiology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Complex study of electrophysical properties (the electrical resistivity r and the temperature coefficient of resistance (TCR) b) of thin-film samples based on ferromagnetic alloy Ni80Fe20 (permalloy) and noble metal Ag in a wide composition range and within the range of thickness 20-100 nm done. Thin films were obtained by the method of electron-beam co-evaporation technique at room temperature. Their composition was investigated using the method of X-ray spectrometry. The phase state was analyzed by the electron diffraction method. It was demonstrated that the crystal structure of thin films stays unchanged during the annealing process to 500 K. The size and concentration dependences of r and b values were obtained. The corresponding maximum and minimum at the concentration of Ag atoms of 50-60 at.% observed at the dependences r(cAg) and b(cAg). Size dependences r(d) and b(d) associated with the size effects in thin-film materials.

Copyright of Journal of Central South University is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Environmentally persistent free radicals (EPFRs) are emerging pollutants stabilized on or inside particles. Although the toxicity of EPFR-containing particles has been confirmed, the conclusions are always ambiguous because of the presence of various compositions. A clear dose–response relationship was always challenged by the fact that the concentrations of these coexisted components simultaneously changed with EPFR concentrations. Without these solid dose–response pieces of evidence, we could not confidently conclude the toxicity of EPFRs and the description of potential EPFR risks. In this study, we established a particle system with a fixed catechol concentration but different reaction times to obtain particles with different EPFR concentrations. Caenorhabditis elegans (C. elegans) in response to different EPFR concentrations was systematically investigated at multiple biological levels, including behavior observations and biochemical and transcriptome analyses. Our results showed that exposure to EPFRs disrupted the development and locomotion of C. elegans. EPFRs cause concentration-dependent neurotoxicity and oxidative damage to C. elegans , which could be attributed to reactive oxygen species (ROS) promoted by EPFRs. Furthermore, the expression of key genes related to neurons was downregulated, whereas antioxidative genes were upregulated. Overall, our results confirmed the toxicity from EPFRs and EPFR concentration as a rational parameter to describe the extent of toxicity. EPFRs are ubiquitously formed in both high-temperature systems and ambient environment matrices. Although previous studies have demonstrated the toxicity of EPFR-containing particles, a clear dose–response relationship was always challenged by the fact that the concentrations of these co-existed components simultaneously changed with EPFR concentrations. This study compared the toxic impacts of particles with various EPFR concentrations, and demonstrated that EPFRs caused concentration-dependent neurotoxicity and oxidative damage to C. elegans. The results of this study confirmed the dose–response evidences of EPFRs and provided significant information for description the potential environmental risks of EPFRs. [Display omitted] • EPFR-containing particles with various EPFR concentrations were established. • Exposure to EPFRs disrupted the development and locomotion of C. elegans. • EPFRs cause concentration-dependent neurotoxicity and oxidative damage. • The expression of key genes related to neurons was downregulated, whereas antioxidative genes were upregulated. [ABSTRACT FROM AUTHOR]

Hydrogen peroxide (H2O2) can be considered as a sterilant or a green propellant. For a common use in industrial application, spray is an effective method to form fine H2O2 droplets. In this paper, electrostatic atomization based on the configuration of needle ring electrodes is proposed to produce H2O2 spray by minimizing its effective surface tension. The breakup performances of H2O2 ligaments can be improved by increasing the electric field intensity, reducing the nozzle size, and adjusting suitable volume flow rate. The smallest average diameter of breakup droplets for 35 wt. % concentration H2O2 solution reached 92.8 μm under optimum operation conditions. The H2O2 concentration significantly influenced the breakup performance owing to the concentration effect on comprehensive physical properties such as density, surface tension, viscosity, and permittivity. The average diameters of breakup droplets decreased with decreasing H2O2 concentration. At 8 wt. % concentration, the average breakup droplet diameter was reduced to 67.4 μm. Finally, electrostatic atomization mechanism of H2O2 solution was analyzed by calculating dimensionless parameters of Re, We, and Oh numbers with the combination of the operation conditions and physical properties for in-depth understanding the breakup behaviors. The calculation showed that the minimum average diameter of breakup droplets was obtained at 8 wt. % concentration at the investigated range of H2O2 concentration, which kept in agreement with the experimental results.

Apparent viscosity is an important parameter for fundamental research and industrial applications of colloidal suspensions. Core–shell particles are generally applied to carry, transport and protect functional materials and ingredients. In the present study the apparent viscosity of the monodisperse core–shell particles in suspensions was analytically formulated by introducing the cell model based on the low Reynolds number hydrodynamics at steady states. Three cell models proposed by Simha, Happel and Kuwabara, respectively, were applied to explore the problems. The core–shell particles were generally considered to be composed of two immiscible concentric liquids, each of which can approach to the solid phase or gas phase in limiting situations. The factors influencing the apparent viscosity from the viscosity of the surrounding fluid were not only the volume fraction of particles in the suspension, but also the viscosity of the fluids constituting the particles. For a dilute multi-emulsion with φ < 0.1 and the core volume of 50 vol% the particle, the apparent viscosity of the suspension slightly increased by less than 1.25 times due to the changes in shell viscosity; however, the apparent viscosity increased significantly by 3.5–4.2 times in a concentration system with φ = 0. 5. In addition, the apparent viscosity also increases monotonically with increasing the core viscosity; while, the influence of core viscosity on apparent viscosity was much less than that of the shell viscosity. Increasing the shell thickness can result in a decrease in the apparent viscosity of the multi-emulsion. • The apparent viscosity a suspension of core–shell particles is analytically formulated by cell models. • The results are in the most general situations for the suspension of monodisperse core–shell particles. • Particle volume fraction, shell viscosity, and core-to-particle volume ratio are important factors influencing the apparent viscosity. • The results could be simplified to the cases of single phase particles (solid sphere, liquid droplet and gas bubble) in the literature. [ABSTRACT FROM AUTHOR]

Ce3+ ion doped BiPO4 phosphors were synthesized by co‐precipitation method using ethylene glycol as capping agent. The prepared phosphors were characterized by XRD, SEM, FT‐IR, UV‐Vis, and PL spectroscopy techniques. The formation of monoclinic phase was confirmed from XRD and FT‐IR studies. SEM study revealed the rice shape morphology of BiPO4:Ce3+ (7at.%). In the photoluminescence analysis, a broad emission band extending in a wide wavelengths range with maxima around 419 and 470 nm was observed under excitation at 370 and 417 nm, respectively. These emission bands are originated from the electronic transitions, viz., 5d → 2F5/2, 2F7/2 of Ce3+ ion. The emission intensity was accentuated with the increase of Ce3+ ion till 7at.% and subsequently attenuated with further increase of Ce3+ ion concentration; which is due to the concentration quenching effect. The BiPO4:Ce3+ (7at.%) sample was characterized for the feasibility of photocatalytic degradation of methylene blue under UV light irradiation and degradation of 90% of the dye was degraded within 120 minutes was observed. From the results, it is believed that the prepared BiPO4:Ce3+ may have potential applications in solid state lighting as well as in photocatalysis for the degradation of organic dyes. [ABSTRACT FROM AUTHOR]

A universal procedure of modeling chromatography separation, based on the plate model, has been developed. On each plate, the equilibrium between the analyte in the mobile and stationary phases is established. This equilibrium may be described by the concentration-dependent partition coefficient. The establishment of the equilibrium on each plate is followed by the displacement of the analyte in the mobile phase by one plate, establishment of new equilibrium, etc. The result is a series of elution curves with positions of maxima dependent on injected mass of the polymer. The procedure has been tested on modeling concentration effects on the basis of dependences of the partition coefficient on local concentrations on each plate. By comparison with the experiment, the slope of the concentration dependence of the partition coefficient of polystyrene in benzene was estimated. It is in qualitative agreement with the literature data obtained by a computer simulation of chromatography separation of polymers in good solvents. [ABSTRACT FROM AUTHOR]

The combustion characteristics of nanofluid fuels have been widely investigated, but rare studies on the atomization were reported. Atomization is an imperative and crucial step to improve the combustion performance of nanofluid fuels, and the secondary breakup of droplets is an important segment for atomization to produce uniform fine droplets and distribute nanoparticles in each droplet. This paper firstly presents the secondary breakup characteristics of single electrified Al/n-decane nanofluid fuel droplets and revealed the mechanism of the secondary breakup. The results demonstrated that fine droplets could be produced in the electrostatic field and Al nanoparticles were distributed in each droplet. Before the breakup, the single electrified droplets experienced surface charge transportation, deformation, and Taylor cone formation. A gradient of the electric field deformed the droplet to produce the Taylor cone. As the Taylor cones were stabilized, the fluid was extruded from the tips of stable Taylor cones to produce jet filament parallel to the electric field direction and correspondingly broke up into fine sub droplets. At the nanoparticle concentration range of 1.0~10 mg/mL, the minimum average diameter of breakup sub droplets could achieve ~55.4 μm at 6.0 mg/mL. The Al nanoparticle concentration had a significant effect on the breakup performance by influencing the physical properties and charging. The order of the Charge-to-Mass ratio magnitude was 10−7~10−5 C/kg. Furthermore, the secondary breakup mechanism of single electrified nanofluid fuel droplets in the uniform electrostatic field was revealed by analyzing the droplet surface charge, deformation, Taylor cone formation, and nanoparticle concentration effect. [ABSTRACT FROM AUTHOR]

The reuse of the printing and dyeing wastewater is limited by its large chromaticity, high alkalinity, high chemical oxygen demand (CODCr), high salinity. In this study, electrodialysis, as a promising technology, was applied for the advanced treatment for printing and dyeing wastewater. With the Design-Expert software and Box–Behnken central composite design method, the optimal operating condition was: operating voltage 85 V, inlet flow rate 1,000 L/h, temperature 25°C, in which the energy consumption was 3.52 kW h/m³ and the desalination processing cost was 0.33 $/m³. The characteristics of the desalination process and membrane pollution were further revealed and discussed. The maximum concentration was obtained at 15,000 mg/L during the concentrated water circulation. And the cation exchange membrane pollution was mainly calcium carbonate, while the anion exchange membrane pollution was organic. In addition, the reversal time fixed at 2 h could effectively reduce membrane fouling. The present work is expected to provide reference technical support for practical industrial applications. [ABSTRACT FROM AUTHOR]

Dynamic viscoelasticity measurements were carried out for N, N-dimethylacetamide solutions of polyacrylonitrile (PAN) frozen at −40 °C to characterize the effect of concentration in the frozen state in relation to the freezing and thawing method of the PAN gel. The storage (G′) and loss moduli (G″) were measured for samples obtained by separating the frozen and unfrozen regions during the thawing step. The G′ were also acquired for solutions without the separation (referred to as post-thawing solution), written as G ′ fro G ′ unfro and G ′ post − thaw for frozen region, unfrozen region, and post-thawing solution, respectively. The relationship, G ′ unfro < G ′ post − thaw < G ′ fro was observed, showing that regions of higher and lower concentrations were developed in the thawing step. ( G ′ fro / G ′ post − thaw ) was considered a relative index of the concentration increase, to be compared for those of the initial and later stages within the thawing step. ( G ′ fro / G ′ post − thaw ) was much greater than 1 in the initial stage, and then decreased and approached 1 in the later stage. The behavior of ( G ′ fro / G ′ post − thaw ) was discussed with reference to the effects of freezing time and concentration on the gelation time. The microscopic separation between the dilute and concentrated phases induced at the freezing step was proposed as the physical process to interpret the viscoelastic data. [ABSTRACT FROM AUTHOR]

Biogenic ferrihydrite nanoparticles were synthesized as a result of the cultivation of Klebsiella oxytoca microorganisms. The distribution of nanoparticles in the body of laboratory animals and the physical properties of the nanoparticles were studied. The synthesized ferrihydrite nanoparticles are superparamagnetic at room temperature, and the characteristic blocking temperature is 23–25 K. The uncompensated moment of ferrihydrite particles was determined to be approximately 200 Bohr magnetons. In vitro testing of different concentrations of ferrihydrite nanoparticles for the functional activity of neutrophilic granulocytes by the chemiluminescence method showed an increase in the release of primary oxygen radicals by blood phagocytes when exposed to a minimum concentration and a decrease in secondary radicals when exposed to a maximum concentration. In vivo testing of ferrihydrite nanoparticles on Wister rats showed that a suspension of ferrihydrite nanoparticles has chronic toxicity, since it causes morphological changes in organs, mainly in the spleen, which are characterized by the accumulation of hemosiderin nanoparticles (stained blue according to Perls). Ferrihydrite can also directly or indirectly stimulate the proliferation and intracellular regeneration of hepatocytes. The partial detection of Perls-positive cells in the liver and kidneys can be explained by the rapid elimination from organs and the high dispersion of the nanomaterial. Thus, it is necessary to carry out studies of these processes at the systemic level, since the introduction of nanoparticles into the body is characterized by adaptive-proliferative processes, accompanied by the development of cell dystrophy and tension of the phagocytic system.

Graphical abstract Highlights • Three situations: single core-shell particle free motion, a core-shell particle moving in a concentric cavity, and core-shell particles in a monodispersed emulsion. • The results are in analytical forms, which are formulated and applied to the most general situations for the emulsion system of core-shell (or encapsulated) particles. • Shell viscosity and shell-to-core radius ratio, as well as boundary effects and particle interactions, are important factors influencing the particle motions. • In the limiting situations, our general results for two-phase particles could be simplified to the cases of solid particles, liquid droplets and gas bubbles in the literature, all of which are single-phase. Abstract In this study, the creeping motions of core-shell particles at low-Reynolds numbers were analyzed and discussed in three cases: (i) a freely translating particle; (ii) a particle in a concentric hole; (iii) particles in a monodisperse suspension. The core and shell were assumed concentric and consist of immiscible liquids. The results revealed the particle motions were significantly influenced by the radius (or volume fraction) and viscosity of the shell and core, especially the shell viscosity. In the limiting situations, our general results for two-phase particles could be simplified to the studies of single-phase particles (solid, liquid or gas bubble) in literature. For the case of a freely suspending particle with the same volume fraction of shell and core, the modified coefficient was reduced by more than 30% as the dimensionless shell viscosity reduced from 100 to 0.01 at η c ∗ = 1 ; however, the coefficient was only slightly reduced by less than 1.5% as the dimensionless core viscosity reduced from 100 to 0.01 at η s ∗ = 1. For the translation of a particle in a concentric hole, the boundary effect of the cavity wall performed to significantly hinder the particle motion. When the volume fraction of the particle in the hole was 0.01 and 0.1, in the case of a 21 = 1.25, η c ∗ = 1 and η s ∗ = 0.01 , the boundary effect retarded the particle velocity to 2/3 and 1/3 of the free particle velocity, respectively. In a monodisperse system, the mean translational velocity of particles was hindered by the hydrodynamic interaction between the particles, and the hindrance effect increased as the particle concentration increased. Particle concentration and shell viscosity were the main properties affecting the fluid dynamics of the suspension. [ABSTRACT FROM AUTHOR]

Previous theoretical studies have found that the concentration variations within a certain range have a prominent effect on inter-mineral equilibrium isotope fractionation (103lnα). Based on the density functional theory, we investigated how the average Ca–O bond length and the reduced partition function ratios (103lnβ) and 103lnα of 44Ca/40Ca in forsterite (Fo) are affected by its Ca concentration. Our results show that Ca–O bond length in forsterite ranges from 2.327 to 2.267 Å with the Ca/(Ca + Mg) varying between a narrow range limited by an upper limit of 1/8 and a lower limit of 1/64. However, outside this narrow range, i.e., Ca/(Ca + Mg) is lower than 1/64 or higher than 1/8, Ca–O bond length becomes insensitive to Ca concentration and maintains to be a constant. Because the 103lnβ is negatively correlated with Ca–O bond length, the 103lnβ significantly increases with decreasing Ca/(Ca + Mg) when 1/64 < Ca/(Ca + Mg) < 2/16. As a consequence, the 103lnα between forsterite and other minerals also strongly depend on the Ca content in forsterite. Combining previous studies with our results, the heavier Ca isotopes enrichment sequence in minerals is: forsterite > orthopyroxene > clinopyroxene > calcite ≈ diopside > dolomite > aragonite. Olivine and pyroxenes are enriched in heavier Ca isotope compared to carbonates. The 103lnα between forsterite with a Ca/(Ca + Mg) of 1/64 and clinopyroxene (Ca/Mg = 1/1, i.e., diopside) is up to ~ 0.64‰ at 1200 K. The large 103lnαFo-diopside relative to the current analytical precision for Ca isotope measurements suggests that the dependence of 103lnαFo-diopside on temperature can be used as a thermometer, similar to the one based on the 103lnα of 44Ca/40Ca between orthopyroxene and diopside. These two Ca isotope thermometers both have a precision approximate to that of elemental thermometers and provide independent constraints on temperature. [ABSTRACT FROM AUTHOR]

The Raman spectra for methyl isothiocyanate (MTC) isolated in an argon matrix at different annealing temperatures and MTC in carbon tetrachloride at different concentrations were collected separately. Concentration‐dependent properties were characterized, and no noncoincidence effect (NCE) was observed. Argon matrix isolated Raman spectra shows that, the SCNC stretching at 6K presents as one distinct peak, it separates into two peaks at 25–35 K and merges as one peak again above 40 K, whereas its frequency shifted to a lower wavenumber. Concentration‐dependent experiments showed the peak frequency of SCNC stretching shifted to a higher wavenumber when the concentrations decreased. Aggregated dimer structures were proposed to explain the MTC SCNC and CS vibrational concentration effects with no NCE phenomenon. Density functional theories were performed to calculate the monomer and dimer of MTC; the dimer structure can explain the experimental data well. The strong antiparallel head‐to‐tail vibrational coupling of the SCNC oscillators in neighbouring molecules accounts for the frequency shifts of the SCNC stretching. [ABSTRACT FROM AUTHOR]

• Increased patch size increases social and solitary bee densities. • Solitary bees are waylaid by mass-flowering vetch patches. • Semi-natural habitats do not influence concentration effect or waylaying effect. • Nesting resources increase concentration effect and waylaying effect. • Landscape-modified concentration and waylaying effects cascade to pollination. Landscape composition is assumed to modify spatial foraging patterns of bees in agricultural ecosystems which subsequently influence pollination services provided to crops. However, empirical evidence to support this prediction is scarce. We investigated the influences of semi-natural habitats and nesting resources on concentration effect and waylaying effect of bees, as well as their consequences on crop pollination in landscapes. Ninety-seven vetch patches with independent gradients of size and distances to nesting sites were selected from 11 agricultural landscapes with independent gradients of surrounding semi-natural habitats and nesting resources. Semi-natural habitats and nesting resources were quantified either by field inspections or from satellite images; flower visitor densities and vetch pollination services were measured across overall flowering seasons. The proportion of semi-natural habitats did not modify the concentration effect or waylaying effect of the abundant and highly social honey bees or the solitary species Anthophora waltoni. The increase in area of brick walls, acting as nesting resources of A. waltoni , increased the concentration effect and the waylaying effect. For other solitary bees, the proportion of semi-natural habitats and the proportion of buildings did not influence the concentration effect or the waylaying effect. Honey bee density, A. waltoni density and other solitary bee density positively predict vetch pollination services. The landscape-modified concentration effect and waylaying effect cascaded to vetch pollination by modifying A. waltoni density. Our findings indicated that landscape composition could modify the spatial foraging patterns of bees and influence pollination services provided to crops, but those varied among different taxonomic groups. [ABSTRACT FROM AUTHOR]

In this paper, we have investigated dielectric properties of azo dye methyl red (MR) doped polymer dispersed liquid crystal (PDLC) composites. Norland optical adhesive (NOA 65) and nematic liquid crystal (E63) materials were used to construction of PDLC composite. In order to observe the effect of MR concentration, PDLC was dispersed with 1, 3 and 5% wt/wt MR. Dielectric properties have been investigated using the dielectric spectroscopy method in the frequency range of 500 Hz to 10 MHz at room temperature. Dielectric constant (ε′ and ε″), dielectric anisotropy (Δε′), relaxation frequency (f R), relaxation time (τ), threshold voltage (V th) and also splay elastic constant (K 11) have been determined for the pure PDLC and its doped version PDLC + 1% MR, PDLC + 3% MR and PDLC + 5% MR composites by using experimental data. Dispersal of increasing MR concentration caused τ, V th , K 11 are decreased whereas f R is increased for the investigated samples. Results show that different MR concentrations significantly affect the dielectric properties of PDLC composites and make it suitable to design new based on PDLC device applications. • Polymer dispersed liquid crystal (PDLC) was dispersed with azo dye methyl red. • MR dispersal decreased threshold voltage and splay elastic constant. • Dielectric anisotropy values increased with increasing concentration of MR. • The relaxation frequency of pure PDLC increased with MR doping ratio. • The relaxation time of pure PDLC decreased with MR doping ratio. [ABSTRACT FROM AUTHOR]

In this paper, the effects of Tb3+ ion concentration on the structural and photoluminescence properties of ZnWO4:Tb3+ have been reported. X-ray diffraction studies indicated that the monoclinic structure of the samples and the crystallinity were found to decrease with the increase of Tb3+ ion concentration due to the distortion in the crystal lattice. The formation of the monoclinic structure was further supported by high resolution transmission electron microscopy and Fourier transform infrared analyses. The transmission electron microscopy image of ZnWO4:Tb3+ (7%) showed a spherical morphology with crystallite sizes in the range of ∼8–12 nm. The excitation spectrum showed a strong broad band originated from the electronic transition within the WO66– group. Upon excitation at 270 nm, the prepared ZnWO4:Tb3+ phosphors exhibited sharp and narrow emission peaks, characteristic of the f–f transitions of Tb3+ ions besides a broad band with the maximum at around 460 nm due to the host lattice. The intensity of the broad emission band was found to decrease gradually with the increase of Tb3+ ion concentration and reached minimum at 7 at%. The decay time of the prepared phosphors was investigated in detail and the maximum average lifetime value is found to be 1.187 ms. [ABSTRACT FROM AUTHOR]

Abstract Equilibrium Mg isotope fractionation properties between aqueous Mg2+ and minerals are the key for the applications of Mg isotopes in geochemistry. This study conducts first-principles molecular dynamics (FPMD) simulations for aqueous Mg2+ based on the density functional theory (DFT). Thirty-five snapshots are extracted from the FPMD trajectories after equilibration for the calculations of the reduced partition function ratio (β factor or 103lnβ). Combining with the β factors of minerals, we found that the β factor decreases in the sequence of lizardite > brucite > aqueous Mg2+ > dolomite > magnesite > calcite > aragonite. Our calculations also confirm the effect of Mg concentration on the β factor of calcite, and further show that the concentration effect is negligible when Mg/(Mg + Ca) (atomic ratio hereafter) is lower than 1/32. Our results depict significant equilibrium Mg isotope fractionations between minerals and aqueous Mg2+ (103lnα minerals-Mg_aq), which are dominantly controlled by the average force constant of Mg in these phases. Compared to aqueous Mg2+, carbonates are enriched in light Mg isotopes but brucite and lizardite show enrichment in heavy Mg isotopes. Among all minerals, 103lnα aragonite-Mg_aq is the largest, which is up to −14‰ at 300 K. Notably, 103lnα calcite-Mg_aq is not only controlled by temperature, but also significantly affected by Mg content in calcite. 103lnα calcite-Mg_aq is negatively correlated with Mg content in calcite. The experimentally measured Mg isotope fractionations between minerals (dolomite, magnesite, brucite) and solution at equilibrium are consistent with our predicted results, showing the accurate description of FPMD simulations for aqueous Mg2+ and the reliability of our calculations. Overall, the calculated equilibrium Mg isotope fractionations between minerals and aqueous Mg2+ provide a guideline for applications of Mg isotopes in aqueous geochemical processes. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Novel Li 2 FeSiO 4 mesocrystals exhibit improved Li-ion storage properties. • EDTA-regulated formation of impurity-free and defect-free hollow Pmn2 1 crystals. • Li 2 FeSiO 4 mesocrystals form via a 4-step hydrothermal crystallization mechanism. Abstract Lithium transition metal orthosilicates such as Li 2 FeSiO 4 (LFS) have been recognized as promising cathode materials for application in Li-ion batteries because of their high theoretical energy density, safety, and benign/abundant element composition. Their development, however, has been hampered by the challenge of obtaining phase-pure and defect-free Li 2 FeSiO 4 nanoparticles as non-optimized crystal properties have an adverse effect on structural stability and electrochemical performance. Considering the sustainable potential of hydrothermal synthesis in producing electrode materials, here we employ this process to systematically study critical synthesis parameters for optimal control of particle size, morphology, phase purity, and defects of Li 2 FeSiO 4 crystallized in the orthorhombic crystal system with space group Pmn 2 1. It is shown that via a combination of elevated FeSO 4 concentration regime and use of EDTA as a complexing agent, phase-pure Pmn 2 1 particle formation can be controlled. Synchrotron-based XRD Rietveld refinement and 57Fe Mössbauer spectroscopy reveal a significant reduction in Li-Fe antisite defects and presence of Fe3+. Additionally, the use of EDTA promotes the formation of unique peanut-shell looking hollow mesocrystals that are advantageous in maximizing electrode/electrolyte contact resulting in higher Li-ion storage capacity than dense LFS particles. On the basis of detailed XRD, SEM, and TEM characterizations, a four-step crystallization mechanism is proposed to explain the formation of the hollow mesocrystals. These findings bring new insight into our pursuit of optimization of Li 2 FeSiO 4 as a cathode material for Li-ion batteries. [ABSTRACT FROM AUTHOR]

Abstract Remediating uranium contamination becomes a worldwide interest because of increasing uranium release from mining activities. Due to ubiquitous presence of pyrite and the application of iron-based technology, colloidal iron oxy-hydroxides such as akaganéite colloid (AKC) extensively exist in uranium polluted water at uranium tailing sites. In this context, we studied individual and co-transport of U(VI) and AKC in water-saturated sand columns at 50 mg/L AKC and environmentally relevant U(VI) concentrations (5.0 × 10−7 ∼ 5.0 × 10−5 M). It was found that, in addition to the impact of pH and ionic strength, whether AKC facilitated U(VI) transport depended on U(VI) concentration as well. The presence of AKC facilitated U(VI) transport at relatively low U(VI) concentration (5.0 × 10−7 ∼ 5.0 × 10−6 M), which was due to the strong adsorption of U(VI) on AKC and faster transport of AKC than that U(VI) as observed in their individual transport experiments. At relatively high U(VI) concentrations (5.0 × 10−5 M), however, AKC impeded U(VI) transport because U(VI) of high concentration decreased AKC colloidal stability and increased AKC aggregation and attachment. Thus, U(VI) and AKC co-transport was even blocked completely at relatively high pH and ionic strength. The mechanisms behind the co-transport of U(VI) and AKC were also confirmed by assessing the evolutions of aqueous pH and AKC zeta potential and particle size distribution in the column effluents. A two-site non-equilibrium model and a two-site kinetic attachment/detachment model well-described the breakthrough curves of U(VI) and AKC, respectively. Knowledge generated from this study provides a thorough understanding of uranium transport in the absence/presence of AKC, and brings new insights into the influence of contaminant concentration on co-transport in the presence of colloids. Graphical abstract Image 1 Highlights • Akaganéite colloids inhibit U(VI) transport at relatively high U(VI) concentration. • U(VI) concentration is a vital factor in regulating its co-transport with AKC. • U(VI) adsorption increases AKC size and impedes AKC transport. [ABSTRACT FROM AUTHOR]

Abstract In this work, we have studied concentration effect of Cadmium Selenide Sulphide/Zinc Sulphide (CdSeS/ZnS) quantum dots (QDs) dispersed on liquid crystalline material, 4-pentyl-4′-cyanobiphenyl nematic liquid crystal (5CB NLC). We used the dielectric spectroscopy technique to obtain electrical and dielectric properties for pure 5CB and doped with QDs form. To observe the effect of CdSeS/ZnS QDs concentration, 5CB was dispersed with 0.05, 0.1 and 0.15 % wt/wt CdSeS/ZnS QDs. Some physical parameters such as real part of dielectric permittivity (ε′), imaginary part of dielectric permittivity (ε"), loss tangent (tan δ) , dielectric anisotropy (Δε′) and ac conductivity (σ ac) of pure 5CB NLC and CdSeS/ZnS QDs doped 5CB NLC composite were measured in the frequency range of 1 kHz–10 MHz at various bias voltages by using dielectric spectroscopy technique at room temperature. In addition, the threshold voltage (V th) and splay elastic constant (K 11) parameters were calculated dependent on doping concentration. The current-voltage (I-V) characteristics of the samples were also investigated. The results showed that the electro-optic and dielectric parameters change significantly with CdSeS/ZnS QDs doping and which were explained by the molecular interaction mechanism between LC molecules and CdSeS/ZnS QDs. [ABSTRACT FROM AUTHOR]

The combustion characteristics of nanofluid fuels have been widely investigated, but rare studies on the atomization were reported. Atomization is an imperative and crucial step to improve the combustion performance of nanofluid fuels, and the secondary breakup of droplets is an important segment for atomization to produce uniform fine droplets and distribute nanoparticles in each droplet. This paper firstly presents the secondary breakup characteristics of single electrified Al/n-decane nanofluid fuel droplets and revealed the mechanism of the secondary breakup. The results demonstrated that fine droplets could be produced in the electrostatic field and Al nanoparticles were distributed in each droplet. Before the breakup, the single electrified droplets experienced surface charge transportation, deformation, and Taylor cone formation. A gradient of the electric field deformed the droplet to produce the Taylor cone. As the Taylor cones were stabilized, the fluid was extruded from the tips of stable Taylor cones to produce jet filament parallel to the electric field direction and correspondingly broke up into fine sub droplets. At the nanoparticle concentration range of 1.0~10 mg/mL, the minimum average diameter of breakup sub droplets could achieve ~55.4 μm at 6.0 mg/mL. The Al nanoparticle concentration had a significant effect on the breakup performance by influencing the physical properties and charging. The order of the Charge-to-Mass ratio magnitude was 10−7~10−5 C/kg. Furthermore, the secondary breakup mechanism of single electrified nanofluid fuel droplets in the uniform electrostatic field was revealed by analyzing the droplet surface charge, deformation, Taylor cone formation, and nanoparticle concentration effect.