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Biology Open Sep 2023The webbed foot structure of mallards (Anas platyrhynchos) exhibits effective anti-subsidence properties when walking on soft ground. To investigate the effects of...
The webbed foot structure of mallards (Anas platyrhynchos) exhibits effective anti-subsidence properties when walking on soft ground. To investigate the effects of quartz sand particle size and thickness on joint angles and the movement patterns of webbed feet, we created a testing substrate with quartz sand and utilized high-speed cameras and kinematic analysis tools for data acquisition. Mallards mainly adjusted the tarsometatarso-phalangeal joint (TMTPJ) during touch-down and lift-off stages in response to increasing particle size or enhanced ground roughness. Conversely, adjustments to the intertarsal joint (ITJ) predominantly took place during mid-stance. Conversely, mallards predominantly adjusted the ITJ during touch-down and lift-off when coping with increased quartz sand thickness, with TMTPJ adjustments mainly occurring at touch-down. As quartz sand particle size increased, the TMTPJ angle increased, the ITJ angle decreased, toe closure advanced, and the duty factor decreased throughout the entire stride cycle. In contrast, increasing quartz sand thickness led to more delayed TMTPJ adjustments, slower webbed foot closure, and an increased duty factor throughout the stride cycle. Mallards modify their leg posture to notably decrease the touch-down foot angle upon encountering sandy terrain. This action subsequently forms a depression beneath their feet, contributing to sand consolidation and limiting flow. During the stance phase, the mallard's weight is distributed across the webbed foot, generating minimal pressure and preventing significant subsidence while walking on sandy ground.
Topics: Quartz; Sand; Biomechanical Phenomena; Particle Size; Lower Extremity
PubMed: 37605960
DOI: 10.1242/bio.060012 -
Sensors (Basel, Switzerland) Jan 2022Carbonate sand is often encountered and utilized as construction material in offshore engineering projects. Carbonate sand particles, which are porous and angular, are...
Carbonate sand is often encountered and utilized as construction material in offshore engineering projects. Carbonate sand particles, which are porous and angular, are found to be highly crushable under high stress conditions, whereas the mechanisms and controlling factors for the crushing of carbonate sand particles are not well developed. The crushability and particle strength of around 400 particles from three fractions (5-10 mm, 2-5 mm, and 1-2 mm) of carbonate sand from the South China Sea were investigated via grain-scale single particle crushing tests. Special emphasis was placed on the effect of external constraint conditions (i.e., coordination number) and intrinsic particle morphology characteristics on the particle strength of carbonate soil. The particle strength of carbonate sand was found to be around half of quartz sand in terms of characteristic stress. Negative correlations, which could be depicted by an exponential equation, were found between the particle size and particle strength. Due to elongated particle shape and tensile stress concentration, a higher coordination number may lower the particle strength, which contradicts what was reported for quartz sands. A series of seven fundamental particle dimensions and five particle shape descriptors was characterized, and the aspect ratio was found to be one of the more influential shape descriptors for particle strength. The results enriched the database for the analysis of highly irregular geomaterial and provided insights into controlling factors of particle strength and crushing mechanisms of the carbonate sand.
Topics: Carbonates; Particle Size; Porosity; Quartz; Sand
PubMed: 35161512
DOI: 10.3390/s22030765 -
European Journal of Pharmaceutical... Jul 2022The definition of the local dissolution environment is central to accurate particle dissolution simulation, and is determined by the apparatus and conditions used. In...
The definition of the local dissolution environment is central to accurate particle dissolution simulation, and is determined by the apparatus and conditions used. In the flow-through apparatus dissolution occurs in the cell, often in a low velocity environment, with the reservoir considered the relevant volume for dissolution kinetics. Dissolution simulations were conducted using a reduced-order model based on the Ranz-Marshall correlation for mass transfer from spherical particles. Using ibuprofen as a model drug, the effect of defining a local volume to simulate dynamic bulk concentration conditions in the flow-through and paddle apparatus was assessed by comparing use of a near particle volume (NPV), extending a distance of one radius from the particle surface, with a flow-through apparatus cell volume or paddle apparatus vessel volume as the relevant instantaneous volume for dissolution. The instantaneous inlet concentration to NPV or cell volume is the reservoir/vessel concentration at that simulation time point, reflecting the continuous input to the cell of more dilute solution from the reservoir (closed system). Additionally, inputting particle size distribution (PSD) instead of a median particle size (MPS) and enabling or disabling particle motion were investigated, in two media (resulting in low and high solubility) and with two fluid velocity conditions in each apparatus. The NPV predicted effects of fluid velocity differences on dissolution in the high solubility medium in the flow-through apparatus, but had no effect on predictive ability in the paddle apparatus. In both apparatuses, simulations were reasonable for the high solubility environment but underpredicted dissolution in the low solubility environment. The PSD option and disabling particle motion increased the predictive ability of the simulations in low solubility media in the flow-through apparatus. The results highlight the necessity to incorporate the local dynamic dissolution conditions in the flow-through apparatus for accurate dissolution simulation, and the challenges of defining an effective particle size for dissolution simulation and of reflecting hydrodynamic complexity in simulating dissolution in the paddle apparatus.
Topics: Chemistry, Pharmaceutical; Computer Simulation; Hydrodynamics; Particle Size; Solubility
PubMed: 35398291
DOI: 10.1016/j.ejps.2022.106185 -
European Journal of Pharmaceutics and... Nov 2022The aim of this study was to determine the thickness of the hydrodynamic diffusion layer (h) of three poor water-soluble compounds under laminar fluid flow using a...
The aim of this study was to determine the thickness of the hydrodynamic diffusion layer (h) of three poor water-soluble compounds under laminar fluid flow using a single particle dissolution technique. The single particle dissolution experiments were performed in a flowing aqueous medium using four different fluid velocities (v), ranging from 46 to 103 mm/s. The particles used had an initial radius (r) of 18.8 to 52.3 μm. The determined h values were calculated from both dissolution experiments and computational fluid dynamics (CFD) simulation. In this study, single particle dissolution experiments gave, with one exception, h values in the range of 2.09 to 8.85 µm and corresponding simulations gave h values in the range of 2.53 to 4.38 µm. Hence, we found a semi-quantitative concordance between experimental and simulated determined h values. Also, a theoretical relation between the dependence of h on particle radius and flow velocity of the medium was established by a series of CFD simulations in a fluid velocity range of 10-100 mm/s and particle size (radius) range of 5-40 µm. The outcome suggests a power law relation of the form h∝rv. In addition, the h seems to be independent of the solubility, while it has a diffusion coefficient dependence. In conclusion, the h values were determined under well-defined conditions; hence, this approach can be used to estimate the h under different conditions to increase the understanding of the mass transfer mechanisms during the dissolution process.
Topics: Computer Simulation; Diffusion; Hydrodynamics; Particle Size; Solubility
PubMed: 36152951
DOI: 10.1016/j.ejpb.2022.09.016 -
Faraday Discussions 2015Crystallization from solution is a crucial process used in the manufacture of a wide variety of materials. The first step in the crystallization process is the birth of...
Crystallization from solution is a crucial process used in the manufacture of a wide variety of materials. The first step in the crystallization process is the birth of a new crystalline phase, which is known as nucleation. Nucleation plays a key role in determining the results of any crystallization process with respect to the size, shape and crystal form obtained. Classical nucleation theory does not adequately explain the crystal nucleation process. Work described in the literature and at this Faraday Discussion describe more complex nucleation mechanisms which are generally known as two-step nucleation models. In addition, as most nucleation is influenced by dust, dirt and container surfaces, the importance of heterogeneous nucleation and the use of templates to accelerate nucleation and influence crystal form are promising methods for the study and control of nucleation. It is also clear from this Faraday Discussion that interest in this topic has grown, and new and novel experimental and modeling approaches are being used for the study of crystal nucleation from solution.
Topics: Crystallization; Particle Size; Solutions; Surface Properties; Thermodynamics
PubMed: 25985136
DOI: 10.1039/c5fd00042d -
Journal of Oleo Science 2020The physicochemical and sunscreen properties of marl as a function of particle size were investigated. The research findings established that the marl under...
The physicochemical and sunscreen properties of marl as a function of particle size were investigated. The research findings established that the marl under investigation consisted of more than 95% calcium carbonate (CaCO). The particles of marl inspected under a scanning electron microscope were calcite, which is the stable polymorph of CaCO, with a rhombohedral structure. The particle size classification by the sieving method showed that grinding using a ball mill could downsize the marl particles by 2 to 3 times, reaching below 15 µm on average. Marl particles showed a tendency to reflect ultraviolet A (UVA) rays rather than UVB rays and a possibility to steadily absorb both UVAII and UVAI. Finer particles obtained after a longer grinding process demonstrated higher efficacy regarding UV reflection and absorption properties. The 3 wt.% marl displayed a sun protection factor (SPF) value of 1 to 2. However, marl demonstrated a good ability to protect against radiation over a broad spectrum range with a critical wavelength above 370 nm. The addition of marl in the formulation containing avobenzone and octinoxate had a positive synergistic effect because the marl was able to increase the UV absorbance efficacy (based on the area under the curve (AUC) value) and SPF value of the cream. Furthermore, it was also discovered that the added marl powder could slow the decrease in UV protection efficacy of the products in terms of the AUC calculated from the absorbance profile after exposure to simulated UV rays with an amplitude range of 10 J/cm to 40 J/cm for 30 min, which was similar to the results obtained from octocrylene and bemotrizinol.
Topics: Calcium Carbonate; Chemical Phenomena; Particle Size; Sunscreening Agents
PubMed: 31902898
DOI: 10.5650/jos.ess19232 -
PloS One 2022We experimentally created a particle size dataset that is based on reduction sequences and raw materials typical of the Middle and Later Stone Age in southern Africa....
We experimentally created a particle size dataset that is based on reduction sequences and raw materials typical of the Middle and Later Stone Age in southern Africa. The reason for creating this new dataset is that current particle size frameworks are based, almost exclusively, on flint and western European knapping methods. We produced the dataset using knapping methods and raw materials frequently encountered in the southern African archaeological record because we wanted to test whether it has the same distribution as particle size datasets experimentally created in Europe, and to initialise the production of a database for use in the analysis of lithic assemblages from southern African Late Pleistocene deposits. We reduced 117 cores of quartz, quartzite, jasper, chalcedony, hornfels, and rhyolite. The knapping methods selected were unidirectional, discoidal, Levallois recurrent and bipolar flaking. In this article we compare this new particle size distribution dataset with the results obtained from previous experiments. We found that the southern African dataset shows a wider size range distribution, which seems to be explained by differences in knapping methods and raw materials. Our results show that there is overlap between the distribution of the southern African experimental knapping dataset and the sorting experiment conducted by Lenoble on flint artefacts in a runoff context. This article shows that a particle size analysis is not sufficient on its own to assess the perturbation of an archaeological assemblage and must be coupled with other analytical tools.
Topics: Particle Size; Technology; Europe; Archaeology; Africa, Southern; Fossils
PubMed: 36584160
DOI: 10.1371/journal.pone.0278867 -
Molecules (Basel, Switzerland) Jan 2023In this paper, methyl glycine diacetic acid (MGDA) was found to have great influence on the morphology and particle size of barium sulfate. The effects of additive,...
In this paper, methyl glycine diacetic acid (MGDA) was found to have great influence on the morphology and particle size of barium sulfate. The effects of additive, concentration, value of pH and reaction temperature on the morphology and particle size of barium sulfate were studied in detail. The results show that the concentration of reactant and temperature have little effect on the particle size of barium sulfate. However, the pH conditions of the solution and the dosage of MGDA can apparently affect the particle size distribution of barium sulfate. The particle size of barium sulfate particles increases and the morphology changes from polyhedral to rice-shaped with the decreasing of the dosage of MGDA. In solution with higher pH, smaller and rice-shaped barium sulfate was obtained. To investigate the interacting mechanism of MGDA, the binding energy between MGDA and barium sulfate surface was calculated. It was found that the larger absolute value of the binding energy would result in stronger growth inhibition on the crystal face. Finally, the experimental data and theoretical calculations were combined to elucidate the interacting mechanism of the additive on the morphology and particle size of barium sulfate.
Topics: Barium Sulfate; Particle Size; Temperature; Surface Properties
PubMed: 36677780
DOI: 10.3390/molecules28020726 -
Molecules (Basel, Switzerland) Nov 2023Cyetpyrafen is a compound that lacks inherent uptake and systemic translocation activity. If mites do not come into direct contact with the pesticide solution on leaves,...
Cyetpyrafen is a compound that lacks inherent uptake and systemic translocation activity. If mites do not come into direct contact with the pesticide solution on leaves, the efficacy cannot be achieved. Controlling the particle size can potentially play a crucial role in the manifestation of efficacy. In this study, high-throughput formulation technology was used to systematically screen a large number of adjuvants to obtain cyetpyrafen formulations. The particle size of the active ingredient in the formulation was measured. By examining the dynamic light scattering and contact angle, we simulated the actual process of the efficacy transmission of cyetpyrafen formulations against . Our results showed that the activity of cyetpyrafen increases as the particle size decreases, suggesting that reducing the particle size can enhance the coverage and deposition on crop leaves, and further improve the dispersion efficiency and enhance spreading capabilities. Furthermore, controlling the particle size at 160 nm resulted in an LC value of 0.2026, which is approximately double than that of the commercial product. As a novel pesticide for mites, our study presents the most effective cyetpyrafen formulation in practice. Our findings provide valuable insights into controlling other mite species that pose a threat to agricultural products.
Topics: Animals; Pesticides; Particle Size; Agriculture; Mites; Lethal Dose 50
PubMed: 37959851
DOI: 10.3390/molecules28217432 -
Ultrasonics Sonochemistry Oct 2021The contribution of ultrasound-aided particle size reduction to the efficiency of the subsequent enzymatic hydrolysis and the accompanying morphological changes of...
The contribution of ultrasound-aided particle size reduction to the efficiency of the subsequent enzymatic hydrolysis and the accompanying morphological changes of bleached cotton and linen powders were investigated. The aqueous suspensions of cellulosic powders were pretreated either with an ultrasonic bath (US-B) or with a horn-type reactor (US-H). Results revealed that the impact of US-H was more pronounced than that of the US-B. Clearly, the linen particles were more sensitive to ultrasonication than cotton. The US-H modified the particle size distribution differently for the cotton and linen powders and reduced the mean size of particles from 49 to 40 µm and from 123 to 63 µm, respectively. A significant increase in the water retention and water sorption capacity was also measured. The smaller particles with increased accessibility were preferably digested in the enzyme treatment, resulting in a considerably higher concentration of reducing sugars and an enrichment of the residual particles with a larger average size (cotton: 47 µm; linen: 66 µm).
Topics: Cellulase; Cellulose; Hydrolysis; Particle Size; Powders; Water
PubMed: 34403893
DOI: 10.1016/j.ultsonch.2021.105711