Inert Particles Research Articles

Disharmony and the Final-Over-Final Condition in Amahuaca

The Final-over-Final Condition (FOFC) rules out head-final projections that immediately dominate head-initial projections. Syntactically inert particles are known to show (apparent) exceptions to FOFC. However, Biberauer (2017) argues that seemingly FOFC-violating particles comply with a version of FOFC that is relativized to heads within an extended projection (Biberauer, Holmberg, and Roberts 2014). I present novel data from Amahuaca (Panoan; Peru) in which FOFC is violated by tense-aspect-mood particles within the verbal extended projection. I argue that this FOFC violation cannot be explained by the mechanisms proposed by Biberauer (2017). Instead, a view of FOFC grounded in restrictions on rightward dependencies (Cecchetto 2013, Zeijlstra 2016) predicts the type of exception found in Amahuaca.

Enhancement of the reactivity of sugarcane bagasse ash for Pozzolan-Lime Paste: Effect of particle size

The aim of this study is to produce Sugar Cane Bagasse Ash (SCBA) with an improved pozzolanic reactivity. Inert particles and impurities present in the initial SCBA were removed by sieving. Resulting sieved SCBA was mixed with hydrated lime to obtain SCBA-lime binders. These prepared alternative SCBA-lime binders were physically, chemically and mechanically characterized. Their thermal conductivity and moisture buffer values were compared to cement, concrete and other metakaolin-lime binders ones.

Pyrolysis as an alternate to open burning of crop residue and scrap tires: Greenhouse emissions assessment and mechanical performance investigation in concrete

In this study, waste from agriculture and industrial sources was transformed into valuable biochar to reduce the environmental threats associated with the open burning of this waste and used as an additive in concrete for the first time to impart superior mechanical characteristics to conventional concrete. Carbonaceous inert particles were derived from the pyrolysis of wheat straw, cotton stalk, and scrap tires. The environmental impact assessment was carried out to gauge the impact of pyrolysis process on char production and the global warming potential for engineered concrete. Based on the analysis, pyrolysis of scrap tires manifested the lowest net global warming potential of −1.285 KgCO 2 -eq. Furthermore, the characterization of synthesized inert particles was carried out by using Laser granulometry, scanning electron microscopy, x-ray diffraction analysis, thermo-gravimetric analysis, and Raman spectroscopy. Thereafter, the mechanical performance of concrete incorporated with synthesized inert particles by 1% of cement weight was evaluated and compared with the reference formulation of concrete having no amount of synthesized inert particles. A significant improvement of 51.42% in terms of flexural resistance was achieved by using pyrolyzed cotton stalk. Fracture toughness index and fracture energy were also improved with the inclusion of these inert particles. To rationalize the improved performance of specimens engineered with synthesized inert particles, fracture path analysis was conducted. In comparison to the reference formulation, composites reinforced with pyrolyzed scrap tires rendered maximum improvement in compressive strength by 43.1%. From the analysis of the emissions to strength ratio of concrete, specimens containing pyrolyzed scrap tires ensued the maximum reduction of 31.31% relative to the reference formulation. • Agricultural residue and scrap tires waste were transfigured to biochar through pyrolysis. • Net negative global warming potential was attained by opting for pyrolysis. • Maximum gain of 51.4% in flexural resistance was obtained with pyrolyzed cotton stalk. • Concrete with 43.1% enhanced compressive strength was made with pyrolyzed scrap tires. • 45.58% increase in strength to emissions ratio was achieved with the addition of pyrolyzed scrap tires.

SIMULATION OF HOMOGENEOUS HYDROGEN-AIR DETONATION INTERACTION WITH POROUS FILTER

Calculations of the interaction of a cellular detonation wave (DW) with an inert porous filter were carried out based on the developed physical and mathematical model of the mechanics of heterogeneous medium which takes into account the detailed chemical kinetics of chemical reactions in the gas phase. Under an inert porous filter, a motionless lattice of inert particles is considered. The following flow regimes were revealed: propagation of attenuated cellular DW at velocities less than the Chapman-Jouguet velocity and detonation failure with the destruction of the cellular structure. Critical volume concentrations of filter particles corresponding to the detonation failure regime were calculated. Dependences of the normalized DW velocity and detonation cell size on the volume concentration of particles in filters were calculated. The concentration limits of detonation (critical volume concentrations of particles lead to detonation failure) in filters with diameters of 50, 100, and 200 µm were determined. The dependences of the normalized DW velocity and size of detonation cell on the volume concentration and diameter of particles in filters were calculated.

Pairing-induced motion of source and inert particles driven by surface tension.

We experimentally and theoretically investigate systems with a pair of source and inert particles that interact through a concentration field. The experimental system comprises a camphor disk as the source particle and a metal washer as the inert particle. Both are floated on an aqueous solution of glycerol at various concentrations, where the glycerol modifies the viscosity of the aqueous phase. The particles form a pair owing to the attractive lateral capillary force. As the camphor disk spreads surface-active molecules at the aqueous surface, the camphor disk and metal washer move together, driven by the surface tension gradient. The washer is situated in the front of the camphor disk, keeping the distance constant during their motion, which we call a pairing-induced motion. The pairing-induced motion exhibited a transition between circular and straight motions as the glycerol concentration in the aqueous phase changed. Numerical calculations using a model that considers forces caused by the surface tension gradient and lateral capillary interaction reproduced the observed transition in the pairing-induced motion. Moreover, this transition agrees with the result of the linear stability analysis on the reduced dynamical system obtained by the expansion with respect to the particle velocity. Our results reveal that the effect of the particle velocity cannot be overlooked to describe the interaction through the concentration field.

Evaluation of parameters controlling calcium recovery and CO2 uptake from desalination reject brine: An optimization approach

A multistage process scheme for extracting valuable minerals from desalination reject brine while simultaneously sequestering CO2 has been proposed. As a part of the proposed scheme, simultaneous removal of calcium ions and CO2 uptake of a magnesium free reject brine was investigated in an inert particle spouted bed reactor (IPSBR) by reacting CO2 with reject brine in presence of NaOH. Response surface methodology was applied to optimize the effect of NaOH dosage, gas flowrate and salinity on the reaction with the target of maximizing calcium removal and CO2 uptake. A second order regression model was generated for both target responses. The predicted responses for both targets were in good agreement with the obtained experimental response. Based on a multivariate optimization, the optimum conditions for NaOH, flowrate and salinity for simultaneous calcium removal and CO2 uptake were found to be 5 g/L, 2 L/min and 75 g/L, respectively. Under these conditions, 100% removal of Ca2+ ions from the brine could be achieved with a CO2 uptake of 5.4 g/L. Moreover, the solid products obtained under the optimum conditions were characterized confirming the formation of high purity calcium carbonates. Based on optimized conditions, the proposed multistage process scheme promises to produce highly pure Mg(OH)2 and CaCO3, while sequestering 5400 tons of CO2 for every million tons of brine treated. The scheme can be further improved by incorporating an electrolysis unit to produce HCl along with NaOH that can be recirculated to eliminate the need for any external addition of NaOH, thus, creating a sustainable process for reject brine management and CO2 sequestration.

Experimental study on fluidization characteristics of vinegar residue in a vibrated fluidized bed

• Vibro-fluidizing behaviors of vinegar residue are experimentally studied. • Inert Geldart-D plastic particles are used to improve the fluidization process. • Minimum fluidization velocities of binary particles are investigated. • Drying rate of vinegar residue increases due to the improving of fluidization. As a by-product in the vinegar brewing process, vinegar residue always has a high moisture content, which is detrimental to the storage and recycle process. The vibrated fluidized bed can be used to dry the vinegar residue. In present work, inert particles were added to a vibrated fluidized bed to improve the fluidization of vinegar residue. Experimental studies were carried out to investigate the fluidization behaviors of the binary mixtures. Flow pattern maps indicated that there was an upper limit to the vinegar residue mass concentration c w at which stable fluidization could be achieved. The minimum fluidization velocity u mf of the binary mixture increased as the vinegar residue mass concentration c w increased and decreased with the increase of the vibration intensity Λ . As increasing vibration intensity Λ or decreasing vinegar residue mass concentration c w , the drying rate of vinegar residue increased.

Numerical analysis of drying characteristics of frozen material immersed in fluidized bed at low temperature under reduced pressure

A spherical frozen material was dried in a fluidized bed of inert particles at a low temperature (lower than the melting point of water) under reduced pressure. To evaluate the drying characteristics of the frozen material, the heat and mass transfers in the material during the drying process were calculated using one-dimensional differential equations. The fitting parameters (accommodation coefficient of internal sublimation and heat transfer coefficient at the surface of the material) were determined to fit the calculation results and the experimental data. Drying characteristics, such as the distributions of moisture content and temperature in the material during drying, were calculated. Operational conditions, such as bed temperature, humidity, and heat transfer coefficient (gas velocity) at the surface of the material were varied in the calculation, and the effects on the end time of drying were estimated. Sublimation in the interior of the material governs the drying characteristics. The dry region in the material became resistant to heat transfer. The calculation results are reasonable for expressing the drying characteristics of freeze-drying, that is, our calculation method can be used to estimate the drying characteristics of frozen material in a fluidized bed.

Investigation of the Rearrangement of Reactive–Inert Particulate Structures in a Single Channel of a Wall-Flow Filter

Wall-flow filters are a standard component in exhaust gas aftertreatment and have become indispensable in vehicles. Ash and soot particles generated during engine combustion are deposited in diesel or gasoline particulate filters. During regeneration, the soot particles are oxidized. The remaining ash particles can form different deposition patterns: a homogenous layer or plug-end filling. It has not yet been clarified whether the plug-end filling is first formed by rearrangements of agglomerates before and during the regeneration of the reactive particles. In this study, experiments are carried out with a single channel of a wall-flow filter. For the investigations, a layer of inert and reactive particles is formed. The rearrangement of agglomerates is achieved by flowing through the model filter channel and observed with a high-speed camera. The particulate structures detach at the channel inlet, are transported along the channel and deposited at the plug. The velocity of the detached agglomerates depends on their size, shape, track and the gas velocity in the channel. If the agglomerate is near the walls of the model filter channel, the gas velocity deviates from the gas velocity in the core flow. The higher the gas velocity, the higher the agglomerate velocity achieved and the larger the detached agglomerates.

Numerical modeling of suppression of detonation waves in hydrogen-air mixture by system of inert particles clouds

The interaction of a detonation wave in a hydrogen-air mixture with a series of clouds of inert particles with diameters of 1, 10, and 100 μm is calculated. The concentration and geometric limits of detonation are determined. It was found that an increase in the particle diameter leads to an increase in the concentration limit and to decrease in the geometric limit of detonation. It has been found that an increase in the number of clouds in a series of clouds makes it possible to increase the length of the gaps between them for the successful failure of detonation. In addition, the longer the clouds of inert particles, the greater the maximum distance between them and the smaller their number is necessary to quench the detonation.

(Digital Presentation) Carbon Quantum Dot Assisted Enhancement of S2 Fluorescence of Near-Infrared Dyes through Immobilization-Induced Emission Effect

Aggregation-induced emission of organic dyes is a phenomenon in which organic luminophores show higher photoluminescence (PL) efficiency in the aggregated state than in a free molecule, due to the freezing rotational degrees of freedom of the luminophore which otherwise quench the PL emission. In many cases, however, coupling of molecules leads to quenching of their emission due to the concentration quenching or self-quenching (exciton-exciton annihilation) effect. Therefore, in order to realize an enhanced PL emission as a result of molecule-molecule interaction a fine balance should be achieved between freezing rotational degrees of freedom of the molecule and escaping self-quenching effect. This could be realized via immobilization of the luminophore onto the inert surface.Here, we demonstrate an enhancement of specific S2 emission of the near-infrared (NIR) dyes of tricarbocyanine family due to their immobilization on the surface of carbon nanoparticles that induce freezing a specific planar conformation of the molecule imposed by the carbon plane of the particle it interact with. Carbon quantum dots serve as inert particles that render an opposite influence on the S1 and S2 emission of the tricarbocyanine dyes. We demonstrate a dual emission of the NIR tricarbocyanine dyes with a bright green S2 fluorescence, which is relatively weak for the free dye molecule but whose quantum yield increases by 2-4 times, together with a strong enhancement of the spontaneous rate of S2 fluorescence, whereas the quantum yield of S1 emission in the NIR decreases by 2-7 times, respectively, as a result of immobilization of the dye molecule via the interaction with carbon quantum dots. The above changes are dependent on the terminal and meso-groups of the dye and the solvent used. The dye immobilization due to interaction with carbon quantum dots causes freezing rotational degrees of freedom of the molecule as indicated by suppression of the dye hot band absorption-assisted anti-Stokes S1 emission.The observed “lighting up” of an anti-Kasha emission, i.e., the emission from Sn (n>1) excited levels, of the NIR chromophores which possess intensive S1 absorption and emission in the NIR region, but which are spectrally silent in the visible, can lead to their potential applications in the fields such as energy conversion, bio-imaging and bio-sensing, sensitization of solar cells, etc.

Effect of particle size and particle loading on the mixing behavior of rod-like particles and spherical particles in a fluidized bed

The spherical inert particles are typically added to a fluidized bed system to promote the fluidization of non-spherical particles. In this study, the mixing behavior of binary mixtures of rod-like particles and spherical particles in a bubbling fluidized bed was investigated using a computational fluid dynamics-discrete element method (CFD-DEM) simulation. The 2k factorial experimental design was used to study the effect of particle size and rod-like particle loading on the average mixing index, as measured by the Lacey mixing index. The use of smaller spheres and rod diameters resulted in a high average mixing index despite increasing the rod weight. The effect estimates from the factorial experimental design indicated that the rod diameter was the most crucial factor for the average mixing index. Furthermore, the sphere diameter also had a significant effect. Nevertheless, the rod weight and interaction of parameters had a slight effect on the average mixing index. These findings confirmed the significance of using inert spherical particles for improving the hydrodynamics properties of non-spherical particles, including the mixing behavior of the binary mixtures system.

Heat transfer and chemical kinetics analysis of a novel solar reactor for hydrothermal processing

This work proposes a novel concept of a hydrothermal solar reactor to convert biomass waste efficiently into bio-products. The operation of this system is studied using heat transfer and kinetic models to assess the concept’s capabilities. The reactor consists of a cylindrical cavity with a window that allows concentrated solar radiation to pass. Inside the cavity, radiative energy is absorbed by an array of tubes, where the reacting water biomass suspension circulates. The cavity walls are assumed to be highly reflecting, and the tube walls to be highly absorbing. Highly-scattering inert fluidized particles are utilized in the cavity to redistribute radiation prior to absorption by the tubes. The cavity-type solar reactor design aims at homogenizing the distribution of radiation absorbed by the tubes, that is, to minimize axial and angular thermal gradients and reduce thermal stresses, given the high operating pressures required for hydrothermal processes. The Monte Carlo Method (MCM) for thermal radiative transfer is used to couple the solar radiation absorption to conduction and convection heat transfer phenomena. The effect of design parameters, like the number of tubes, their location, the relative size of the cavity, and the scattering particles concentration, is evaluated in the reactor thermal performance. The results indicate that adding the participating medium and carefully choosing the number and distribution of tubes allows reactor thermal efficiencies above 80% while reducing thermal gradients within the tubes. Moreover, the analysis shows the solar reactor concept can attain biogas and biocrude yields slightly above 20% and 30%, respectively.

No inflammatory effects after acute inhalation of barium sulfate particles in human volunteers

BackgroundMost threshold limit values are based on animal experiments. Often, the question remains whether these data reflect the situation in humans. As part of a series of investigations in our exposure lab, this study investigates whether the results on the inflammatory effects of particles that have been demonstrated in animal models can be confirmed in acute inhalation studies in humans. Such studies have not been conducted so far for barium sulfate particles (BaSO4), a substance with very low solubility and without known substance-specific toxicity. Previous inhalation studies with zinc oxide (ZnO), which has a substance-specific toxicity, have shown local and systemic inflammatory respones. The design of these human ZnO inhalation studies was adopted for BaSO4 to compare the effects of particles with known inflammatory activity and supposedly inert particles. For further comparison, in vitro investigations on inflammatory processes were carried out.MethodsSixteen healthy volunteers were exposed to filtered air and BaSO4 particles (4.0 mg/m3) for two hours including one hour of ergometric cycling at moderate workload. Effect parameters were clinical signs, body temperature, and inflammatory markers in blood and induced sputum. In addition, particle-induced in vitro-chemotaxis of BaSO4 was investigated with regard to mode of action and differences between in vivo and in vitro effects.ResultsNo local or systemic clinical signs were observed after acute BaSO4 inhalation and, in contrast to our previous human exposure studies with ZnO, no elevated values of biomarkers of inflammation were measured after the challenge. The in vitro chemotaxis induced by BaSO4 particles was minimal and 15-fold lower compared to ZnO.ConclusionThe results of this study indicate that BaSO4 as a representative of granular biopersistent particles without specific toxicity does not induce inflammatory effects in humans after acute inhalation. Moreover, the in vitro data fit in with these in vivo results. Despite the careful and complex investigations, limitations must be admitted because the number of local effect parameters were limited and chronic toxicity could not be studied.

Effects of inert dispersed particles on the propagation characteristics of a H2/CO/air detonation wave

In this study, numerical simulations are carried out by utilizing Eulerian-Lagrangian methods to investigate effects of the inert dispersed particles on the propagation characteristics of the H2/CO/air detonation wave. The results show that the inert particles reduce the temperature and velocity of both dispersed and continuous phases. The particles absorb heat from the gas, which alters the spatial location where the chemical equilibrium is achieved upstream of the detonation wave. Increasing the particle mass ratio reduces the detonation wave propagation velocity and hydrodynamic thickness, while it increases the velocity fluctuations at the detonation front. In contrary to this, enlarging the particle diameter leads to the augmentation of the detonation wave propagation velocity and hydrodynamic thickness, while it induces non-monotonic changes in the velocity fluctuations at the detonation front. The results show that the effects of the inert particles on the detonation wave are dominated by the relative scales of the particle relaxation time and the detonation propagation time.

Effects of Dense Inert Particle Loading in Shocked Energetic Materials

AbstractMetal particles are often added to solid‐fuel rocket motors and weapon systems to boost detonation propagation or to increase impact energy. Aside from the chemical effects of reactive particles, even inert particle effects can be significant on detonation properties due to the momentum and the energy exchanges between the phases. Therefore, a study of inert particles, that can exhibit direct effects on shock‐to‐detonation‐transition (SDT) depending on particle loading and its material properties, is needed. This work numerically investigates the effects of dense inert particle loading on SDT in energetic material (EM). The focus here is on local non‐equilibrium (NE) effects in particle‐added EM mixture and its correspondence to observed parametric trends on detonation. An Eulerian‐Eulerian (EE) framework capable of modeling dense‐dilute particles is used within a well‐established multi‐phase solver to capture dispersed motion in a reactive condensed phase. The numerical approach is first validated against available experimental data, and this is followed by an investigation of particle effects over a range of parameters where a condition‐dependent trend is observed. Focusing on the two‐phase NE effects, the dynamic and the thermal disparities between particles and EM are quantified to demonstrate the effect of relaxation parameters on the observed detonation quantities. The reduction in peak pressure and detonation velocity is observed to follow NE strengths and corresponding relaxation rates. An assessment of the effects of various particle loading parameters, i. e., concentration, size, density, and specific heat, on SDT is performed along with quantifying the relaxation process. All particle loading parameters show a range‐dependent effect on detonation properties, and the observed results demonstrate the relevance of two‐phase NE and corresponding relaxation processes.

Kaolin particle film limits grapevine downy mildew epidemic under open‐field conditions and stimulates the plant defence response

Background and Aims Grapevine downy mildew, the most destructive grapevine disease caused by Plasmopara viticola, requires more environmentally friendly control measures. A chemically inert kaolin particle film (KPF) was tested for the control of downy mildew. Methods and Results Grapevines were pretreated with KPF before P. viticola infection under field conditions, then an epidemic was monitored for 2 years (2020 and 2021). A 6% KPF pretreatment significantly delayed the epidemic onset by 1–2 weeks and decreased the disease index by 30% compared to the untreated vines. The concentration of hydrogen peroxide and malondialdehyde in leaves was reduced by the KPF treatment, indicating mitigation of the oxidative damage caused by P. viticola infection. The protective effect of the application of KPF may be due to the increased activity of antioxidant enzymes and antioxidant metabolites. The activity of disease resistance enzymes and the expression of related genes were also increased by KPF treatment. Conclusions Kaolin particle film reduced grapevine downy mildew and reinforced the defence response of grapevines cultivated in the field. Significance of the Study The positive effect of KPF against downy mildew for grapevines in the field indicated that there is potential to develop KPF for the control of downy mildew.

Flexible habitat choice of pelagic bacteria increases system stability and energy flow through the microbial loop

AbstractPelagic bacteria can be classified into free‐living and particle‐attached life modes, which either dwell in the water column or attach to suspended particles. Bacteria with a generalist life style, however, can actively shift between these two habitats. Globally increasing densities of natural and artificial particles enhance habitat heterogeneity, with potential consequences for system stability and trophic transfer through aquatic food webs. To better decipher the dynamics of microbial communities, we investigated the influence of adaptive vs. fixed habitat choice on species coexistence for a simplified bacterial community by analyzing a corresponding food web model, consisting of two specialist bacterial prey species (free and attached), a generalist bacterial prey species with the ability to shift between both habitats, and two protist predators, specialized on either water or particle compartment. For simplicity we assume a shared resource pool, considering particles only for colonization but not as a source for nutrients or carbon, that is, inert particles like microplastics or inorganic sediments. The model predicts coexistence on a cyclic attractor between fixed and flexible bacteria, if the costs for adaptive habitat choice can be balanced by adaptation speed. The presence of adaptive prey dampens predator–prey cycle amplitudes, contributing to system stabilization resulting in higher mean predator biomass compared to specialist prey only. Thus, in pelagic microbial systems, flexible habitat choice at the prey level has important implications for system stability and magnitude of energy flow through the microbial loop.

Effects of eco powders from solid waste on freeze-thaw resistance of mortar

This study investigates the long-term properties of green mortar, including mechanical properties and freeze-thaw resistance. Within the green mortar mixtures, the recycled concrete powder (RCP) and spontaneous combustion gangue powder (SCGP) were designed alone or in combination as a substitute for different proportions of cement. The findings indicate that the pozzolanic activity of eco powders and the mixed eco powders (RCP: SCGP = 1:1, by mass ratio) can meet the criteria for pozzolanic activity. Benefitting from the prolonged pozzolanic reaction, the green mortar containing 30% eco powder (e.g., RCP, SCGP, or RCP + SCGP) can achieve acceptable mechanical behavior at 300 days. Experimental results reveal that SCGP has positive effects on the freeze-thaw resistance of green mortar, while RCP behaves oppositely. This phenomenon is attributed to the different contributions caused by different eco powders on the pore structure of green mortar. The better freeze-thaw resistance of RM-0R-30C can be attributed to a dense microstructure of green mortar by pozzolanic reaction induced by SCGP. The filling effect of RCP gradually weakens after the initial damage under frost attack, and the high water absorption of inert RCP particles leads to aggravated freeze-thaw damage as the number of freeze-thaw cycles increases.

Macroparticle-enhanced bioleaching of uranium using Aspergillus niger

Fungal leaching is a promising method for uranium extraction from its low-grade ores. Nevertheless, an efficient leaching process needs to be developed. Herein, we proposed a macroparticle-enhanced method by which millimetre-sized inert particles were added to a culture medium for a two-step fungal leaching process. The impact of the addition of glass bead macroparticles on Aspergillus niger morphology and subsequent uranium extraction were investigated. Pellet-type morphology was found to be favorable to uranium extraction, and bio-ore pellets with 4–5 mm diameters showed a high leaching efficiency. However, the morphology of A. niger was driven toward dispersed mycelia and uranium extraction decreased at 210 rpm. The maximum uranium extraction of 75.5% was achieved with glass beads (40 g/L, 0.5 mm) at 180 rpm, an increase of approximately 10% compared to the control without glass beads. Analyses of organic acids by ion chromatograph showed that at these conditions, the amount of citric acid and oxalic acid consumed for uranium dissolution was the greatest. The three dimensional (3D) structures of bio-ore pellets were characterized by nano-computed tomography (nano-CT), and they presented different structures under the conditions with and without glass beads. The effect of stress energy (SE) induced by the glass beads was evaluated by a mathematical model, which revealed that the proper amount of energy input would contribute to increased uranium extraction.