Spherical Beads Research Articles

The effects of different pellet shapes on streamer dynamics in patterned dielectric barrier discharges

Abstract Dielectric barrier discharges (DBD) are frequently used for gas conversion for environmental protection by removing harmful components from gas streams and converting them into value added products. DBD operation is typically combined with catalysts placed on spherical dielectric beads in the plasma volume to enhance conversion rates and energy efficiency. However, the presence of such pellets blocks the gas flow and their random arrangement leads to unstable discharges. In this work, we use an advanced plasma source, the patterned DBD (p-DBD), where dielectric pellets are immersed into an electrode at fixed and controllable positions to enhance plasma stability and control. Based on experiments and simulations we study the effects of the pellet shape and the driving voltage on the spatio-temporally resolved dynamics of volume and surface streamers, that ultimately determine the generation of reactive species, plasma-catalyst coupling, and conversion rates/efficiencies via electron heating. The pellet shape is found to influence the streamer speed and the generation of energetic electrons. Via their effects on the effective capacitance of the pellet, shapes with a flatter plasma facing apex are polarized more strongly by approaching volume streamers. This results in a stronger local enhancement of the electric field at the apex, higher volume streamer speed, and more electron heating at this position. Depending on the surface topology maximum electron impact excitation of the background gas is observed at different locations along the pellet's surface. Changing the polarity of the rectangular driving voltage waveform provides control of the direction of positive/negative streamer propagation and selectivity towards anode or cathode directed streamer movement.

Adsorption of phosphate by ZnCr-LDHs and its zirconium-based hydrogel spheres in water

Phosphate, as one of the main sources of eutrophication problems, has received much attention from researchers in recent years. The process of encapsulating layered double hydroxides (LDHs) in a hydrogel provides an application idea for the removal of phosphate from water by powder materials. LDHs nanomaterials have the advantages of excellent performance, low cost and no secondary pollution, and are limited by application challenges such as low hydraulic conductivity and difficulties in solid-liquid separation. In this study, ZnCr layered double hydroxides (ZnCr-LDHs) were prepared by hydrothermal synthesis using triethanolamine as a base source, and Zr4+ was utilized to prepare spherical hydrogel beads loaded with ZnCr-LDHs sodium alginate. The successful synthesis of ZnCr-LDH materials and Zirconium alginate hydrogel beads encapsulated with ZnCr-LDH was validated through an array of characterization techniques, including Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FT-IR). The effects of adsorbent dosing, solution pH, adsorption time, initial phosphate concentration, temperature and other anions on phosphate adsorption were investigated. The results showed that under certain experimental conditions (adsorbent dose = 1.0 g/L, initial phosphate concentration = 100 mgP/L, reaction time = 12 h), the composite material could effectively remove phosphate with the maximum adsorption up to 134.95 mgP/g, which effectively solved the solid-liquid separation difficulties of powdered nanomaterials.

Hierarchical Modeling of the Thermal Insulation Performance of Novel Plasters with Aerogel Inclusions

Silica aerogel possesses a significantly lower thermal conductivity compared to still air at room temperature, thanks to its high porosity and advanced thermal and physical properties. It is extensively investigated for its potential use as an insulation material, usually being incorporated into other matrix materials, such as cement plasters, to enhance the overall thermal performance with minimal weight load. The development of lightweight thermal insulation materials is a key step in reducing energy consumption in hot and cold environments during construction and in thermal equipment. The superior insulation capabilities of aerogels stem from their nanostructured SiO2 framework, which induces nanoscale rarefaction effects on the enclosed air near the SiO2 structure. This study reconstructed the nanostructured SiO2 network of modern aerogels using microscopy imaging and the literature data and integrated it into sophisticated heat transfer simulations at a microscopic level to predict its thermal performance. The simulation assumed conduction as the primary energy dissipation mechanism, incorporating local rarefaction effects based on kinetic theory approaches. SiO2 aggregates were modeled as interconnected strings of spherical beads, with variations in the aggregate size explored in a parametric study. Nanoscale rarefaction phenomena, such as slip wall and Knudsen diffusion, prevalent at these grain sizes and structures, were incorporated to refine the modeling approach. The degree of the aerogel content relative to the effective properties of the multiphasic material was then investigated systematically along the multilayered mortar thickness and on a representative multiphasic layer at the mesoscopic level. The results quantify the significant decrease in the thermal conductivity of the heterogeneous material as the porosity of the aerogel increased. The insulation performance of this aerogel incorporated into cement plasters was assessed with this hierarchical approach and validated against experimental data, providing insights for the optimization of the fabrication process and potential applications in construction.

Quantitative Investigation of Layer-by-Layer Deposition and Dissolution Kinetics by New Label-Free Analytics Based on Low-Q-Whispering Gallery Modes

A new instrument for label-free measurements based on optical Low-Q Whispering Gallery Modes (WGMs) for various applications is used for a detailed study of the deposition and release of Layer-by-Layer polymer coatings. The two selected coating pairs interact either via hydrogen bonding or electrostatic interactions. Their assembly was followed by common Quartz Crystal Microbalance (QCM) technology and the Low-Q WGMs. In contrast to planar QCM sensor chips of 1 cm, the WGM sensors are fluorescent spherical beads with diameters of 10.2 µm, enabling the detection of analyte quantities in the femtogram range in tiny volumes. The beads, with a very smooth surface and high refractive index, act as resonators for circular light waves that can revolve up to 10,000 times within the bead. The WGM frequencies are highly sensitive to changes in particle diameter and the refractive index of the surrounding medium. Hence, the adsorption of molecules shifts the resonance frequency, which is detected by a robust instrument with a high-resolution spectrometer. The results demonstrate the high potential of the new photonic measurement and its advantages over QCM technology, such as cheap sensors (billions in one Eppendorf tube), simple pre-functionalization, much higher statistic safety by hundreds of sensors for one measurement, 5–10 times faster analysis, and that approx. 25, 000 fewer analyte molecules are needed for one sensor. In addition, the deposited molecule amount is not superposed by hydrated water as for QCM. A connection between sensors and instruments does not exist, enabling application in any transparent environment, like microfluidics, drop-on slides, Petri dishes, well plates, cell culture vasculature, etc.

Edible liquid marbles stabilized with millimeter-sized spherical particles

Liquid marbles (LMs) are millimeter-sized liquid droplets in a gaseous phase coated with solid particles. The LM technology allows liquid droplets to be treated as solid particles. As an LM stabilizer, edible particles are of particular interest, especially for applications in the food industry. However and surprisingly, there are limited numbers of reports describing LMs stabilized with edible particles. In this study, we utilize silver dragees, which are millimeter-sized spherical sugar beads coated by silver overlayers used for decorating cakes and cookies, as edible particles to stabilize LMs. The silver dragees surface was modified using stearic acid to work as an effective LM stabilizer by adsorbing at the gas-liquid interface. LMs with millimeter and centimeter sizes can be fabricated. Due to high adsorption energy and jamming effect of the modified dragees at gas-liquid interface, LMs with non-equilibrium shapes including intricate ones with varying curvatures can be prepared. Developing LMs with customizable shapes is crucial for expanding their potential applications and versatility as functional systems for food applications. We therefore show how these customizable-shaped LMs can be utilized as an edible decoration material for food applications.

Immersed boundary method for dynamic simulation of polarizable colloids of arbitrary shape in explicit ion electrolytes.

We develop a computational method for modeling electrostatic interactions of arbitrarily shaped, polarizable objects on colloidal length scales, including colloids/nanoparticles, polymers, and surfactants, dispersed in explicit ion electrolytes and nonionic solvents. Our method computes the nonuniform polarization charge distribution induced in a colloidal particle by both externally applied electric fields and local electric fields arising from other charged objects in the dispersion. This leads to expressions for electrostatic energies, forces, and torques that enable efficient molecular dynamics and Brownian dynamics simulations of colloidal dispersions in electrolytes, which can be harnessed to accurately predict structural and transport properties. We describe an implementation in which colloidal particles are modeled as rigid composites of small spherical beads that tessellate the surface of the particle. The electrostatics calculations are accelerated using a spectrally accurate particle-mesh-Ewald technique implemented on a graphics processing unit and regularized such that the electrostatic calculations are well-defined even for overlapping bodies. We illustrate the effectiveness of this approach with a comprehensive set of calculations: the induced dipole moments and forces for individual, paired, and lattice configurations of spherical colloids in an electric field; the induced dipole moment and torque for anisotropic particles subjected to an electric field; the equilibrium ion distribution in the double layer surrounding charged colloids; the dynamics of charged colloids; and the behavior of ions in the double layer of a polarizable colloid under the influence of an electric field.

Hybrid composite beads of chitosan/graphene oxide for dye adsorption: characterizations, kinetic modeling and toxicity study

The current study aimed to the preparation of graphene oxide impregnated chitosan– polyvinyl alcohol hybrid beads (GO/CS-PVA) for the removal of Reactive Black 5 (RB5) dye from wastewater solutions, presenting them as a cost-effective alternative for wastewater treatment. These hybrid beads were fabricated using a dripping technique in an aqueous solution. The surface and structure of the material before and after adsorption process were studied by analyzing FTIR spectroscopy and Scanning electron microscope (SEM) as well as adsorption capacity was also evaluated. The results proved the successful synthesis of GO/CS-PVA beads and elucidated the physical adsorption mechanism of RB5. SEM images revealed uniform spherical beads with a rough surface, approximately 752 μm in diameter. Additionally, the evaluation of adsorption capacity showed that the optimum condition for RB5 adsorption is at pH = 3 while the kinetic investigations revealed that the adsorption process adhered to the pseudo-second-order model, indicating a chemisorption reaction. Furthermore, an increase in temperature from 25 to 65 °C enhanced the maximum adsorption capacity of GO/CS-PVA beads by 34%. The cytotoxic effect of the hybrid as measured on adipose derived stem cells via the MTT assay was negligible. In conclusion, it was proved that the eco-friendly GO/CS-PVA beads adsorbents can efficiently remove RB5 from wastewater in practical applications.

A universal drag model for liquid-solid fluidization: Experiment, data-driven modeling, CFD modeling and simulation

Various industrial applications are performed in liquid-solid fluidized beds where drag force plays a significant role in affecting the expansion characteristics of granular-bed, and then determines the mass/heat transfer performance. This study employs dimensionless learning data-driven modeling method, which is derived from the principle of dimensional invariance, to automatically discover the relationship between the drag coefficient and hydraulic dimensionless numbers from the liquid-solid fluidization data. It is found that the Fr number (=ul2/gds) also plays important role in improving the prediction accuracy of drag model except for Re number (=dsulρl/μl). The proposed data-driven modeling method has desired robustness, and the yielded drag model can be applicable to other liquid-solid systems, such as water-polystyrene spheres and water-coal particles, although it is derived from the fluidization of spherical glass beads in rising tap-water. The proposed drag model can also provide good CFD simulation results that agree very well with the experiment data with the relative error less than 5 %.

Shear Mechanism and Optimal Estimation of the Fractal Dimension of Glass Bead-Simulated Sand

Spherical glass beads weaken the influences of particle morphology, surface properties, and microscopic fabric on shear strength, which is significant for revealing the relationship between macroscopic particle friction mechanisms and the particle size distribution of sand. This paper explores the shear mechanical properties of glass beads with different particle size ratios under different confining pressures. It obtains the particle size ratio and fractal dimension D through an optimal mechanical response. Simultaneously, we explore the range of the fractal dimension D under well-graded conditions. The test results show that the strain-softening degree of Rs is more obvious under a highly effective confining pressure, and the strain-softening degree of Rs can reach 0.669 when the average particle size d¯ is 0.5 mm. The changes in the normalized modulus ratio Eu/Eu50 indicate that the particle ratio and arrangement are the fundamental reasons for the different macroscopic shear behaviors of particles. The range of the peak effective internal friction angle φ is 23 °~35 °, and it first increases and then decreases with the increase in the effective confining pressure. As the average particle size increases, the peak stress ratio MFL and the peak effective internal friction angle φ first increase and then decrease, and both can be expressed using the Gaussian function. The range of the fractal dimension D for well-graded particles is 1.873 to 2.612, and the corresponding average particle size d¯ ranges from 0.433 to 0.598. Under the optimal mechanical properties of glass beads, the particle size ratio of 0.25 mm to 0.75 mm is 23:27, and the fractal dimension D is 2.368. The study results provide a reference for exploring friction mechanics mechanisms and the optimal particle size distributions of isotropic sand.

Contamination of consumer composts by metals, microplastics and other microscopic debris.

Very little information exists on the particle and chemical contamination of consumer (horticultural) composts. In this study, anthropogenic microcellulosics (AMCs), microplastics (MPs) and other microscopic debris, along with anthropogenically impacted metals (Cu, Zn, Pb), have been determined in 12 composts (seven garden composts and five growbags) purchased at outlets in the UK. AMCs and MPs, determined microscopically, were present in all samples at up to about 1100kg-1 dw. AMCs were more abundant and were dominated by fibres constructed of rayon and cotton, while petroleum-based MPs exhibited a greater diversity in shape and polymeric construction (including polyolefins, polyethylene terephthalate, polyvinyl chloride, resins, paints and rubbers). Other microdebris, present in much smaller concentrations in the composts, consisted of fragments of glass, metal and machined wood and spherical glass beads. Concentrations of the anthropogenically impacted metals, Cu, Pb and Zn, determined directly by energy-dispersive X-ray fluorescence spectrometry, were heterogeneously distributed and averaged 52.4, 192 and 51.6mgkg-1 dw, respectively. Although concentrations of anthropogenic particles were not related to cost or type of compost, physico-chemical properties or metal concentrations, a significant relationship between Pb content and particle diversity (number of polymers and debris types) was established. This relationship might result from the general contamination of the environment by both Pb and anthropogenic particulates, or the association of the metal with various types of material (e.g. paints, polyvinyl chloride, glass). Despite the ubiquity and diversity of MPs and microdebris in consumer composts, an understanding of their impacts on plant growth, either directly or indirectly (e.g. by interacting with metals), is unknown.

A systematic review on the occurrence and removal of microplastics during municipal wastewater treatment plants

This study uses a systematic review of Scopus, Web of Science, and ScienceDirect databases to investigate the removal rate of microplastics (MPs) at various stages of municipal wastewater treatment plants (WWTPs). In this context, 25 articles were included, which investigated 54 WWTPs. Results showed that the overall removal efficacy of MPs in studied WWTPs is about 88.1 (± 18.8) percent. The contribution of preliminary, primary, secondary, tertiary, and disinfection treatment in the removal of entry MPs are 37.4% (± 24), 62.7% (± 20.8), 63.7% (± 24.8), 62.8% (± 29.5), and 12.5% (± 15.7) (mean (± SD)), respectively. The critical aspects about MPs occurrence in WWTPs influent were summarized and on average 2267.2 (± 5376.4) MPs particles per liter (P/L) were present with a considerable wide range of 0.28 to 31400 P/L. In the next section, details about frequent shape (i.e., spherical (beads, pellets, granules), lines (filaments, fibers), films, fragments, and foams) of MPs in influent and effluent of included WWTPs and their removal efficacy during treatment steps are given. Finally, this study highlights future challenges in MP removal and suggests key areas for further research, such as improving treatment efficiency and understanding MP characteristics.

Ion-Exchange Membranes Extract Lithium From North Sea Oilfield Brines

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 215585, “Lithium Extraction From North Sea Oilfield Brines Using Ion-Exchange Membranes,” by Botelho Disu, Roozbeh Rafati, and Amin S. Haddad, University of Aberdeen, et al. The paper has not been peer reviewed. _ The annual demand for lithium for low-carbon technology applications has been growing exponentially. A necessity exists in the current environment for continuous lithium production from both conventional sources and novel extraction sites from alternative brine resources such as oil fields and geothermal sites. in the complete paper, the lithium potentiality of the UK North Sea is evaluated. Identification of North Sea Lithium-Rich Oil and Gas Fields Maps show lithium-ion concentration diffusing from 55 ppm in the western region into low concentrations in the central, northern, and eastern regions of the UK North Sea. Such estimates suggest lithium enrichment in oilfield brine from the Beatrice, Clymore, Gannet, Cly, Auk, and Flumar fields. However, because such map distribution of lithium is achieved based only on one-third of the imputed data, a correlative evaluation with the entire body of data is needed to provide a much more feasible interpretation. When lithium distribution was evaluated simultaneously with strontium/iron/potassium (Sr/Fe/K) total dissolved solids, the rich brine was primarily located across the central, eastern, southern, and western fields. The central and eastern concentrations were estimated to have a lithium-rich brine with concentrations of up to 40 ppm, with lithium-ion presence gradually increasing toward the east. Most of the fields in this region are oil fields, including Montrose, Arbroath, Ula, Nelson, Brisling, Gyda, Ekofisk, and Bream, with Harald possibly being the only gas field with lithium-enriched brine. On the other hand, the lithium-rich fields in the southern and western regions are all gas fields, including the Esmond, Anglia, Lemman, Ann, and Viking fields. Statement of Theory and Definition The economic feasibility of lithium extraction from brine has been observed to be a function of its initial concentration. For oilfield brines, when using novel direct-lithium-extraction (DLE) technologies, the brine concentration economic feasibility for production is reduced to a cutoff benchmark of 50 ppm. However, ongoing developments in DLE technologies envision a feasible, efficient, and highly selective recovery of lithium from brines with low concentrations, even sea water. Manganese ion-sieve powder is a DLE technology that has gathered growing interest. However, one of the main challenges of its application in continuous industrial processes consists of operational challenges that its original powder form can cause. Therefore, forming is necessary if ion-sieve adsorbents are to have an industrial application. This paper has reported and discussed the experimental results of forming the adsorbent powders into different ion-exchange membranes (foam, flat sheet, and granular spherical beads) and their application for lithium extraction from simulated North Sea brine. The complete paper details the description and application of experimental equipment and processes.

Experimental investigation of erosion and transport of binary sediment in sewer pipes

ABSTRACT Understanding sediment transport in storm sewer systems is essential to prevent pipe blockages, associated flooding, and maintenance. In this research, a laboratory study was conducted in a pipe to investigate the erosion and transport process of a binary sediment, i.e., a material with two different particle sizes. The sediment used in this study was a mixture of two sizes of spherical glass beads (0.8 and 4 mm) and two sizes of natural soil (sand and gravel), with different amounts of small size particles. The results show that the critical velocities for the initiation of sediment transport increase linearly with a decrease in the fine particle content of the mixture. A method to predict the critical velocity of a binary mixture is proposed based on the fine content and the critical velocity of single-size large particle and single-size small particle sediments. The transport rate of the mixture lies between that of the single-size large sediment and single-size small sediment. The transport rate is increased with an increase in the fine content, which means that mixing small particles with large particles can significantly increase the transport rate of large particles and the total transport rate.

Spherical gamma-alumina macroscopic beads as easy to remove adsorbents for water remediation: Modeling of indigo carmine case study

In light of the constantly increasing need for health and environmental preservation, in this study, alumina beads, with economic advantages and the benefit of being easily removed and recovered by the treated wastewater, were synthesized and investigated for the removal of Indigo Carmine (IC), selected as a representative of polluting organic dyes. The structure and physical properties of the adsorbent were characterized by Simultaneous Thermal Analysis (STA), X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FT-IR), and Energy Filtered Transmission Electron Microscopy (EFTEM). To maximize the efficiency of IC dye removal from wastewater by γ-alumina beads, control parameters like dye concentration, adsorbent amount and contact time were modified. The optimal operational conditions were assessed via the D-optimal design of response surface methodology (RSM-D-optimal). The maximum adsorption capacity of alumina beads was found to be 126 mg/g. Langmuir and Freundlich models were applied to adsorption isotherms with an R2 value of 0.956 and 0.9901, respectively, pointing to multilayer adsorption phenomena. Millimeter-sized beads of the loaded adsorbent were finally easily removed by the treated water and tested in a subsequent run of water remediation. The results reveal that γ−alumina beads can be considered a potential adsorbent for IC removal from wastewater, as they combine satisfactory remediation features with easy collection and removal after the treatment, eventually more efforts are required to make beads reusable.

Development and evaluation of biodegradable alginate beads loaded with sorafenib for cancer treatment

The study focused on fabricating and characterizing sorafenib-loaded calcium alginate beads for potential cancer therapy application. The beads were synthesized via ionotropic gelation using calcium chloride as a crosslinker. Successful sorafenib encapsulation was confirmed through various analytical techniques, including FTIR, XRD, SEM, and UV-Vis spectroscopy. FTIR analysis showed shifts in characteristic bands, indicating effective drug loading. XRD patterns revealed both amorphous and crystalline characteristics, with peaks corresponding to the drug and polymer. SEM images depicted spherical beads with surface roughness. UV-Vis spectrum analysis demonstrated high encapsulation efficiencies ranging from 99.48 % to 99.82 %, depending on the sorafenib concentration. Biodegradation studies suggested the beads' potential for drug delivery, showing gradual weight and shape loss. Antioxidant assays indicated superior scavenging activity, while antibacterial assays showed good activity against Bacillus species. Cytotoxicity studies revealed specific toxicity against MCF7 breast cancer cells. Drug release data fitted well with the first-order model, indicating controlled release properties. These findings highlight the potential of sorafenib-loaded calcium alginate beads as an effective delivery system for cancer therapy.

Chitosan/Poly(maleic acid-alt-vinyl acetate) Hydrogel Beads for the Removal of Cu2+ from Aqueous Solution.

Covalent cross-linked hydrogels based on chitosan and poly(maleic acid-alt-vinyl acetate) were prepared as spherical beads. The structural modifications of the beads during the preparation steps (dropping in liquid nitrogen and lyophilization, thermal treatment, washing with water, and treatment with NaOH) were monitored by FT-IR spectroscopy. The hydrogel beads have a porous inner structure, as shown by SEM microscopy; moreover, they are stable in acidic and basic pH due to the covalent crosslinking. The swelling degree is strongly influenced by the pH since the beads possess ionizable amine and carboxylic groups. The binding capacity for Cu2+ ions was examined in batch mode as a function of sorbent composition, pH, contact time, and the initial concentration of Cu2+. The kinetic data were well-fitted with the pseudo-second-order kinetic, while the sorption equilibrium data were better fitted with Langmuir and Sips isotherms. The maximum equilibrium sorption capacity was higher for the beads obtained with a 3:1 molar ratio between the maleic copolymer and chitosan (142.4 mg Cu2+ g-1), compared with the beads obtained using a 1:1 molar ratio (103.7 mg Cu2+ g-1). The beads show a high degree of reusability since no notable decrease in the sorption capacity was observed after five consecutive sorption/desorption cycles.

Experimental measurements of the granular density of modes via impact.

The jamming transition is an important feature of granular materials, with prior work showing an excess of low-frequency modes in the granular analog to the density of states, the granular density of modes. In this work, we present an experimental method for acoustically measuring the granular density of modes using a single impact event to excite vibrational modes in an experimental, three-dimensional, granular material. We test three different granular materials, all of which are composed of spherical beads. The first two systems are monodisperse collections of either 6mm or 8mm diameter beads. The third system is a bidisperse mixture of the previous two bead sizes. During data collection, the particles are confined to a box; on top of this box, and resting on the granular material, is a light, rigid sheet onto which pressure can be applied to the system. To excite the material, a steel impactor ball is dropped on top of the system. The response of the granular material to the impact pulse is recorded by piezoelectric sensors buried throughout the material, and the density of modes is computed from the spectrum of the velocity autocorrelation of these sensors. Our measurements of the density of modes show more low-frequency modes at low pressure, consistent with previous experimental and numerical results, as well as several low-frequency peaks in the density of modes that shift with applied pressure. Our method represents an experimentally simple technique for investigating the granular density of modes and may increase the accessibility and number of such measurements.

Engineering the nanozyme hydrogel beads by polyvinyl alcohol/chitosan encapsulation with recyclable and sustainable catalytic activity for visual analysis of hydrogen peroxide

BackgroundHydrogen peroxide (H2O2) plays a vital role in human health and have been regarded as a crucial analyte in metabolic processes, redox transformations, foods research and medical fields. Especially, the long-time and excessive digestion of H2O2 may even cause severe diseases. Although conventional instrumental methods and nanozymes-based colorimetric methods have been developed to accomplish the quantitative analysis of H2O2, the drawbacks of instrument dependence, cost-effectiveness, short lifespan, non-portable and unsustainable detection efficacies will limit their applications in different detection scenarios. ResultsHerein, to address these challenges, we have proposed a novel strategy for nanozyme (RuO2) hydrogel preparation by the solid support from cross-linked polyvinyl alcohol (PVA) and chitosan (CS) to both inherit the dominant peroxidase-like (POD) activity and protect the RuO2 from losing efficacies. Taking advantages from the hydrogel, the encapsulated RuO2 were further prepared as the regularly spherical beads (PCRO) to exhibit the sustainable, recyclable, and robust catalysis. Moreover, the intrinsic color interferences which originated from RuO2 can be avoided by the encapsulation strategy to promote the detection accuracy. Meanwhile, the high mechanical strength of PCRO shows the high stability, reproducibility, and cyclic catalysis to achieve the recyclable detection performance and long lifetime storage (40 days), which enables the sensitively detection of H2O2 with the detection limit as lower to 15 μM and the wide detection linear range from 0.025 to 1.0 mM. SignificanceOn the basis of the unique properties, PCRO has been further adopted to construct a smartphone detection platform to realize the instrument-free and visual analysis of H2O2 in multi-types of milk and real water samples through capturing, processing, and analyzing the RGB values from the colorimetric photographs. Therefore, PCRO with the advanced detection efficacies holds the great potential in achieving the portable and on-site analysis of targets-of-interest.

Effect of Drained Multi-Directional Loads on Liquefaction Resistance of Granular Material

ABSTRACT It is well recognized that the liquefaction resistance is closely related to the consolidation stress in soils. However, previous studies investigated the effects of unidirectional consolidation loads rather than multi-directional consolidation loads on liquefaction resistance. In this study, two types of granular materials, spherical glass beads and irregularly-shaped sands, are tested under undrained conditions with the uni- and bi-directional loads to investigate the liquefaction resistance. The effects of consolidation loads on liquefaction resistance can be explained in terms of material anisotropy. In simple shear tests, the stress- and strain-controlled loading paths are adopted for the consolidation and the undrained shear process, respectively. The results indicate that the liquefaction resistances of both materials consolidated under the multi-directional consolidation loads are higher than those consolidated under the linear loads. More consolidation loading cycles induce a better liquefaction resistance of the specimens at a given relative density. In addition, the influence of consolidation stress on liquefaction resistance is demonstrated by the anisotropy of specimens. Cyclic vertical stress, unidirectional shear stress, and bidirectional shear stress applied during consolidation produce greater isotropy and improve the liquefaction resistance of the specimen compared with the monotonic vertical stress, and their effects align with an increasing order.

On the effects of dispersing polar nanoparticles in liquid crystals

We have investigated the effect of adding polar rodlike nanoparticles (NPs) to a liquid crystal using Monte Carlo simulations. The mesogens (Ms) are represented with Gay–Berne elongated ellipsoids endowed with a central axial electric dipole. A NP is instead modelled by a overall rod-like set of rigidly assembled Lennard–Jones spherical beads (Orlandi et al. Phys. Chem. Chem. Phys. 18, 2428–2441 (2016). doi:10.1039/C5CP05754J) that are either non-polar or endowed with a central axial dipole of different strengths. We consider two cases: one of strong NP-M affinity and weak NP-NP interactions (case 1) and the opposite one of weak NP-M affinity and strong NP-NP interactions (case 2). We find that for case 1 adding polar NPs slightly lowers the nematic-isotropic transition temperature T NI which instead, for case 2, is essentially unaffected. Having strongly polar, instead of non-polar NPs reduces the T NI difference with the pristine one, while significantly increasing the dielectric anisotropy in the nematic phase, which could be useful in applications.