Placement Of Particles Research Articles

Mesoscopic simulations of a fracture process in reinforced concrete beam in bending using a 2D coupled DEM/micro-CT approach

In this study, a complex fracture process in a short rectangular concrete (RC) beam reinforced by one longitudinal bar (without vertical reinforcement) and subjected to quasi-static three-point bending was numerically explored in 2D conditions. A critical diagonal shear crack in the beam caused it to fail during the experiment. The numerical simulations were conducted with a classical particle discrete element method (DEM). A three-phase concrete description (aggregate, mortar, and interfacial transitional zones (ITZs) around aggregates) accounted for the concrete heterogeneity. In mesoscopic DEM calculations based on a 2D X-ray CT scan, the actual shape and placement of aggregate particles in concrete were taken for granted. In the study, the steel bar with ribs was replicated. ITZ was also assumed between the bar and mortar. Without imposing any bond-slip law, a geometrical bar/concrete interface condition was explicitly considered. The focus was on the force–deflection diagram, fracture process, contact forces, and stresses along the bar. A good level of agreement about the evolution of the vertical force versus the deflection and failure mechanism was attained between DEM analyses and in-house laboratory tests despite simplified 2D conditions. A strong effect of concrete mesostructure on the crack pattern was found.

Constraining Predicate Fronting

A number of languages have been argued to establish basic word order by means of VP-fronting (e.g., Kayne 1994, Massam 2001). However, many such analyses overgenerate: some material thought to be VP-internal never appears fronted and must apparently always be stranded (Chung 2005, Massam 2010). Here, I provide novel evidence for VP-fronting in an SVO language, the understudied Polynesian outlier Imere (Vanuatu), motivated by the placement of adverbial particles. But this analysis too faces the stranding problem: VP-fronting cannot drag along any DPs, PPs, or CPs. To solve this issue, I propose that VP-fronting is accompanied by distributed deletion (Fanselow and Ćavar 2001), driven by a constraint that favors realizing only the verb. I extend this analysis to eight other VP-fronting languages, from five language families. In all these languages, what remains in the fronted VP is a structurally reduced dependent, like an adverbial particle or a determinerless object. Building on Clemens 2014, 2019, I adopt a constraint that requires dependents of a head that spell out in the same phase to remain adjacent, thus surviving distributed deletion.

Characterization of acorn oil and its application on carnauba wax-based oleogel and chocolate spread

This study aimed to characterize acorn oil (AO) and carnauba wax-based acorn oil oleogel (AOG) and the effect of AOG replacement on the textural and sensorial properties of chocolate spread. Oil yields from cold-pressing (Quercus longipes) were around 14%wt with a nice nutty smell. The main fatty acids of AO were included oleic, linoleic, and palmitic acid (44, 38, and 10%wt) respectively. The prepared AOG using 6%wt of carnauba wax (CW) showed high strength (G' > 100 mPa) and oil binding capacity ∼87 %. Based on microstructure assays platelet-like and β’ polymorphic triglyceride crystalline networks were formed in AOG. The Pickering AOG/water emulsions in the volumetric ratio of from 90:10 up to 40:60 were stable due to the placement of CW-based AOG particles at the interface of water/oil as Pickering stabilizer. The high physical stability of the emulgel against phase separation is considered an important advantage for using oleogel in chocolate spread formulations instead of vegetable oils, which usually have a high percentage of oil release. The spreads prepared by replacing 50%wt AOG with butter showed acceptable textural and sensorial properties.

Gold and Iron Oxide Nanoparticle Assemblies on Turnip Yellow Mosaic Virus for In-Solution Photothermal Experiments.

The ability to construct three-dimensional architectures via nanoscale engineering is important for emerging applications in sensors, catalysis, controlled drug delivery, microelectronics, and medical diagnostics nanotechnologies. Because of their well-defined and highly organized symmetric structures, viral plant capsids provide a 3D scaffold for the precise placement of functional inorganic particles yielding advanced hierarchical hybrid nanomaterials. In this study, we used turnip yellow mosaic virus (TYMV), grafting gold nanoparticles (AuNP) or iron oxide nanoparticles (IONP) onto its outer surface. It is the first time that such an assembly was obtained with IONP. After purification, the resulting nano-biohybrids were characterized by different technics (dynamic light scattering, transmission electron microcopy, X-ray photoelectron spectroscopy…), showing the robustness of the architectures and their colloidal stability in water. In-solution photothermal experiments were then successfully conducted on TYMV-AuNP and TYMV-IONP, the related nano-biohybrids, evidencing a net enhancement of the heating capability of these systems compared to their free NP counterparts. These results suggest that these virus-based materials could be used as photothermal therapeutic agents.

Fabrication and characterization of food-grade pea protein-ascorbic acid nanoparticles-stabilized Pickering emulsion

In this study, modified pea proteins (PP) were prepared by heat treatment, ultrasound, adjusting the pH to 9, and the addition of ascorbic acid (AA) to stabilize the Pickering emulsion (PE) with a 50% volume fraction of corn oil. The solubility of PP after different treatments was higher in all treatments than in the native state. FTIR and SDS-PAGE results confirmed that a covalent bond (Maillard reaction) was formed between PP and AA, which occurred more strongly in the heat-treated suspensions. The nanoparticles produced from ultrasonication of PP and the PP/AA complexes were able to stabilize the emulsion with a high volume fraction of oil as novel Pickering emulsifiers. In ultrasonicated PP and PP/AA complexes, the reduction of interfacial tension and particle size and increase of contact angle caused a significant improvement in the physical stability of the PE, which can be the result of regular placement of protein particles at the water-oil interface. The treatment corresponds to highly stable PE, heat-treated PP in the presence of AA in alkaline conditions (HPP.AA.pH), increased the contact angle of PP from ∼ 42 to 77, and decreased interfacial tension from ∼ 25 to 14. These PEs showed high physical and oxidative stability. According to CLSM images, the type of PE was oil in water, and PP particles surrounded the oil droplets. The results of this research could be effective in developing PP-based low-fat formulations with improved oxidative stability by utilizing different treatments, including ultrasonic treatment and/or complex formation between PP and AA.

Clinical efficacy of guided bone regeneration in peri-implantitis defects. A network meta-analysis.

Guided bone regeneration (GBR) at peri-implantitis-related bone defects involves the placement of bone-filler particles in the intrabony defects and the application of a barrier membrane. The efficacy of different GBR-supported reconstructive measures as well as their potential superiority compared to non-GBR-supported treatment strategies for bone defects at peri-implantitis sites, however, remains unclear. Therefore, this analysis was designed to evaluate the long-term (≥12 months) clinical efficacy of GBR-supported reconstructive surgical therapy for peri-implantitis-related bone defects. In terms of resolving inflammation, the implementation of GBR protocols applying xenogenic bone substitutes yielded a higher reduction of bleeding on probing and probing depth value compared to the GBR protocol applying autogenous bone. Furthermore, for the changes in bleeding on probing and probing depths, GBR approaches using xenogenic bone showed superiority over the non-GBR treatments. Xenogenic bone with or without a barrier membrane was associated with improved radiographic bone levels and less soft tissue recession compared to the use of a GBR protocol implementing autogenous bone. Nonetheless, when interpreting this findings, the limited number of available studies with low to serious risk of bias and the short follow-up periods limited to 12 months should be considered.

Argument placement in Norwegian

This paper gives an overview of the results from three data collection sessions that took place in Norway in 2018, which specifically targeted the placement of subjects, objects and particles in main clauses. The results reveal a fairly high amount of variation in the relative linear order of phrasal subjects and negation, and phrasal objects and verb particles, while the placement of pronouns show little or no variation. We view these results in a wider context of variation within the North Germanic languages, and furthermore explicitly describe the structure of the collected data, and how to access it in the online Nordic Word Order Database.

Argument placement in Icelandic

This paper gives an overview of the Icelandic data in the Nordic Word Order Database (NWD; Lundquist et al. 2019). The data were collected from 30 native speakers of Icelandic, and the experimental task elicited argument placement (subject shift, object shift, long object shift, particle shift). The results confirm that subject shift of definite subjects and pronouns is produced categorically in Icelandic, as is pronominal object shift. With regard to the placement of non-pronominal objects relative sentence adverbials and particles, there is, on the other hand, variability. Rather surprisingly, the results suggest that the placement of subjects (initial or postverbal) influences non-pronominal object shift. With respect to the ordering of objects and particles, the distinction between directional and metaphorical particles is relevant. The patterns are partly different from what we find in the comparable data from the other North Germanic languages (also available in NWD).

Scotch® Magic Tape™ and the Analysis of Settled Dust

An environmental “sticky” tape lift contains hundreds to tens of thousands of individual particles. Each particle is unique, and its optical properties indicate the particle’s identity and history. Environmental particles are not isolated and by association occur with other particles, which may provide information on the source of an individual particle. The physical placement of particles on a surface carries information about the individual particles as well as the microenvironment associated with the surface at that location. Sampling is a destructive process because information is lost no matter how the surface is sampled. Therefore, the chosen sampling procedure must retain the data required for the analysis. Tape lifts can retain data on particle concentrations, particle identification, particle sources, transport mechanisms active at the sample location, and more. The type and quality of tape, how it is processed, and how it is analyzed will affect the extent to which the environment has been characterized. 3M Scotch® Magic™ Tape (Magic Tape) and the light microscope have been used to make tape lifts by the author since 1970 for characterizing environments. The advantages and disadvantages of using this sampling method are briefly discussed.

Embossed Template Induced Particles Assembly for Heterostructures and the Application in High‐Security Encryption

AbstractThe coassembly of primary particles into heterostructures represents a significant strategy for advanced fabrication of multi‐functional materials or devices, and templated assembly has shown remarkable advantage for deterministic placement of particles and the efficient integration with substrates. However, template induced particles coassembly, which is significant for integrating multicomponents at desired positions, is still challenging. Herein, a facile strategy of embossed templateinduced particles coassembly for diverse superstructures and precise patterns is reported. Tunable region selective assembly of particles is demonstrated by controlling the resistance force via designing the embossed edge and surface roughness of the template. Through regulating the template morphologies and particles composition, well‐controlled coassembly of “flower” shaped heterostructure and chiral superstructure arrays are realized. Furthermore, the printable nanomaterials self‐assembly template is employed to achieve totally bottom‐up fabrication of excitation responsive heterostructure arrays, in which the multi‐photons process based energy transfer is studied to show the application in high‐secure encryption. With the advantage of accurate position and compatible to different materials, this strategy is expected to provide a promising platform for fabricating micro/nanoscale advanced devices.

Mechanical optimization of an Al-Al2O3 composite nanowire via molecular dynamics simulation and metaheuristic optimization

In the present study, mechanical properties optimization is investigated for an Al-Al2O3 composite nanostructure. The Al-Al2O3 composite nanostructure is considered an Aluminum nanowire reinforced by spherical Al2O3 particles. The structure tensile test is simulated via molecular dynamics simulation using LAMMPS. The mechanical properties of the composite are extracted from the obtained stress-strain curve of the composite. The important mechanical properties include maximum stress and toughness. An optimization process is then applied to maximize the mechanical properties of the composite via metaheuristic optimization algorithms including Genetic Algorithm (GA), Ant Colony (ACO), and Grey Wolf Optimizer (GWO). Since the studied nanostructure is mono crystal, the reinforcing mechanism differs from that of a grained macro material. Therefore, the optimization variables are not confined to size and volume fraction but they also include the location of the particles. The optimization is performed for 0.05 and 0.10 volume fractions and different particle sizes with respect to the location of particles. Applying the optimization process, the mechanical properties of the studied composite nanowire are substantially improved for tensile loading. The results reveal that the placement of the particles has a considerable effect on the improvement of mechanical characteristics. At last, a pattern is presented for the placement of particles to achieve the highest tensile characteristics of Al-Al2O3 composite nanowires.

Combinatorial scheme of random placement of particles into cells of several types

Combinatorial scheme of random placement of particles into cells of several types

Dynamic modeling of particle reinforced composites and its Charpy impact test verification

The placement of particles with complex shapes is one of the difficulties in the modeling of particle reinforced composites. Therefore, a novel modeling method named the velocity-controlled rigid body dynamics method was proposed to establish the geometric model of the particle reinforced composites in ABAQUS/CAE. The method, using rigid particles motion, collision, and separation mechanisms to avoid particles overlapping, can be applied to construct the geometric models of the composites with particles of various shapes. Numerical simulations based on this modeling method and laboratory experiments were adopted to study the effect of particle volume fraction on the impact toughness of ZTA particle reinforced Fe45 matrix composites (ZTAp/Fe45). The results showed that the impact toughness of the composites decreased rapidly to about 1/6 of that of the pure matrix with the introduction of ZTA particles, and then as the particle volume fraction increased, the impact toughness of the composites slowly decreased. The results of the impact tests were consistent with the numerical simulation results, which verified the practicability, validity, and reliability of the algorithm and models.

Experimental Study of Transport Behavior of Swellable Microgel Particles in Superpermeable Channels for Conformance Control

SummaryGel treatment is an effective way to attack excessive water production during oil development. The transport behavior of gel materials in reservoirs is of crucial importance to the effectiveness of gel treatments. The aim of this paper is investigating the transport behavior of swellable micrometer-sized preformed particle gels (PPGs, or microgels) through superpermeable (super-K) channels. Sandpacks with permeabilities ranging from 27 to 221 darcies were used to mimic the super-K channels. Multiple pressure sensors were applied along the sandpack models to monitor the propagation behavior of the microgels. The tested microgel particles could transport through the super-K channels, and a higher driving pressure gradient was required when the particle/pore size ratio was larger. The pressure gradient distribution along the super-K channels was relatively uniform when the particle/pore ratio was low (less than 1.3). However, the inlet section would show increasingly higher pressure gradients as the particle/pore ratio was increased, indicating increased difficulty in propagation. The propagation of the gel particles was significantly slower compared with the carrying fluid. The delayed propagation behavior was more pronounced when the particle/pore ratio was higher. The injection pressure was much less sensitive to the injection flow rate compared with a Newtonian fluid. The gel dispersion exhibited an apparent shear thinning (pseudoplastic) behavior when transporting through the porous channels. Breakage of the gel particles was observed especially at high superficial velocities. The particle breakage was partially responsible for the apparent shear thinning behavior. The breakage phenomenon was in favor of deep placement of the gel particles. The channel permeabilities were significantly reduced by the microgels, bringing sufficient resistance to subsequent waterflooding (more than 99.5%). At given matching size conditions, softer gels were more likely to establish in-depth placement and uniform water blocking capacity in the channels. The microgel particles exhibited salinity-responsive behavior to the post-brine flush. The gel particles could shrink and reswell according to the salinity of the injected water. Possibilities were discussed to use this salinity-responsive behavior. Also, the microgels exhibited a particular disproportionate permeability reduction (DPR) effect. After gel injection, the channel permeability to water flow was reduced by more than 20 to 92 times of the permeability to oil flow. This work provides important support to understand the transport behavior of gel particles in super-K channels. The achievements are helpful for gel product selection and gel treatment design.

Designer Nanomaterials through Programmable Assembly

AbstractNanoparticles have long been recognized for their unique properties, leading to exciting potential applications across optics, electronics, magnetism, and catalysis. These specific functions often require a designed organization of particles, which includes the type of order as well as placement and relative orientation of particles of the same or different kinds. DNA nanotechnology offers the ability to introduce highly addressable bonds, tailor particle interactions, and control the geometry of bindings motifs. Here, we discuss how developments in structural DNA nanotechnology have enabled greater control over 1D, 2D, and 3D particle organizations through programmable assembly. This Review focuses on how the use of DNA binding between nanocomponents and DNA structural motifs has progressively allowed the rational formation of prescribed particle organizations. We offer insight into how DNA‐based motifs and elements can be further developed to control particle organizations and how particles and DNA can be integrated into nanoscale building blocks, so‐called “material voxels”, to realize designer nanomaterials with desired functions.

Designer Nanomaterials through Programmable Assembly.

Nanoparticles have long been recognized for their unique properties, leading to exciting potential applications across optics, electronics, magnetism, and catalysis. These specific functions often require a designed organization of particles, which includes the type of order as well as placement and relative orientation of particles of the same or different kinds. DNA nanotechnology offers the ability to introduce highly addressable bonds, tailor particle interactions, and control the geometry of bindings motifs. Here, we discuss how developments in structural DNA nanotechnology have enabled greater control over 1D, 2D, and 3D particle organizations through programmable assembly. This Review focuses on how the use of DNA binding between nanocomponents and DNA structural motifs has progressively allowed the rational formation of prescribed particle organizations. We offer insight into how DNA-based motifs and elements can be further developed to control particle organizations and how particles and DNA can be integrated into nanoscale building blocks, so-called "material voxels", to realize designer nanomaterials with desired functions.

Colloidal particle aggregation: mechanism of assembly studied via constructal theory modeling

The assembly of colloidal particles into ordered structures is of great importance to a variety of nanoscale applications where the precise control and placement of particles is essential. A fundamental understanding of this assembly mechanism is necessary to not only predict, but also to tune the desired properties of a given system. Here, we use constructal theory to develop a theoretical model to explain this mechanism with respect to van der Waals and double layer interactions. Preliminary results show that the particle aggregation behavior depends on the initial lattice configuration and solvent properties. Ultimately, our model provides the first constructal framework for predicting the self-assembly of particles and could be expanded upon to fit a range of colloidal systems.

Experimental Study of Microgel Conformance-Control Treatment for a Polymer-Flooding Reservoir Containing Superpermeable Channels

SummaryPolymer flooding has been widely used to improve oil recovery. However, its effectiveness would be diminished when channels (e.g., fractures, fracture-like channels, void-space conduits) are present in a reservoir. In this study, we designed a series of particular sandwich-like channel models and tested the effectiveness and applicable conditions of micrometer-sized preformed particle gels (PPGs, or microgels) in improving the polymer-flooding efficiency. We studied the selective penetration and placement of the microgel particles, and their abilities for fluid diversion and oil-recovery improvement. The results suggest that polymer flooding alone would be inefficient to achieve a satisfactory oil recovery as the heterogeneity of the reservoir becomes more serious (e.g., permeability contrast kc/km > 50). The polymer solution would vainly flow through the channels and leave the majority of oil in the matrices behind. Additional conformance-treatment efforts are required. We tried to inject microgels in an attempt to shut off the channels. After the microgel treatment, impressive improvement of the polymer-flooding performance was observed in some of our experiments. The water cut could be reduced significantly by as high as nearly 40%, and the sweep efficiency and overall oil recovery of the polymer flood were improved. The conditions under which the microgel-treatment strategy was effective were further explored. We observed that the microgels form an external impermeable cake at the very beginning of microgel injection and prevent the gel particles from entering the matrices. Instead, the microgel particles could selectively penetrate and shut off the superpermeable channels under proper conditions. Our results suggest that the 260-µm microgel particles tested in this study are effective to attack the excessive-water-production problem and improve the oil recovery when the channel has a high permeability (>50 darcies). The gels are unlikely to be effective for channels that are less than 30 darcies because of the penetration/transport difficulties. After the gels effectively penetrate and shut off the superpermeable channel, the subsequent polymer solution is diverted to the matrices (i.e., the unswept oil zones) to displace the bypassed oil. Overall, this study provides important insights to help achieve successful polymer-flooding applications in reservoirs with superpermeable channels.

On the fringe between West and North Germanic

Abstract In this paper I investigate the early language contact between North Frisian and Danish. Since we have no direct evidence for this language contact apart from the layer of medieval Danish interferences in Modern North Frisian, the question arises, whether it is possible to say anything about the specific type of language contact that has taken place in the Middle Ages on the basis of the modern language data and with the help of language contact theory. Taking the lead of van Coetsem’s language contact theory, I discuss two phenomena in the (morpho)syntax of Modern North Frisian, the placement of directional particles and the inventory of verbal particles, and argue that they point to a language contact situation in which a considerable number of Danish-speakers shifted to North Frisian.

A Concept-based Approach to the Instruction of the Chinese ba-construction

This study explores a concept-based instruction approach to promoting second languagedevelopment of the ba-construction, a known difficult area, by six collegelevelEnglish learners of Chinese in a two-month enrichment program. We developedSCOBAs to explain the syntactic, semantic, and pragmatic constraints of the baconstruction,as well as its similarities and differences from the canonical Subject-Verb-Object (SVO) and topicalization Object-Subject-Verb (OSV) word orders. Theparticipants’ productive use of the construction was assessed with two translations(one on paper and one on the computer) and a cartoon description task followinga pretest, posttest, and delayed posttest format. Semi-structured interviews and theparticipants’ verbalization data were also collected. By comparing the participants’gain scores in relation to maximum possible scores, we found that the participants had made large gains throughout the study and retained much of the gain two weeks after the posttest. The microgenetic analyses of the participants’ production data showed improvement in the use of resultative verb compound, perfective marker–le, and the placement of directional particles. Finally, the verbalizations data indicated improvement in conceptual understanding of the ba-construction in terms of its scope, i.e., not just the physical placement of objects, but the accentuation of the results of the verbal action.