Preferred penetration of active nano-rods into narrow channels and their clustering

2021 ◽  
Author(s):  
Zhengjia Wang ◽  
Kang-Ching Chu ◽  
Heng-Kwong Tsao ◽  
Yu-Jane Sheng
Keyword(s):  
Narrow Channels ◽  
Nano Rods ◽  
Entropic Effect ◽  
Size Of Particles

In a channel connected to a reservoir, passive particles prefer staying in the reservoir than the channel due to entropic effect, as the size of particles is comparable to that...

scholarly journals Hydrodynamic and entropic effects on colloidal diffusion in corrugated channels

2017 ◽  
Vol 114 (36) ◽  
pp. 9564-9569 ◽  
Author(s):  
Xiang Yang ◽  
Chang Liu ◽  
Yunyun Li ◽  
Fabio Marchesoni ◽  
Peter Hänggi ◽  
...  
Keyword(s):  
Brownian Dynamics ◽  
Numerical Models ◽  
Particle Diameter ◽  
Ionic Channels ◽  
Dynamics Simulation ◽  
Brownian Dynamics Simulation ◽  
Narrow Channels ◽  
Colloidal Diffusion ◽  
Entropic Effect ◽  
Hydrodynamic Effects

In the absence of advection, confined diffusion characterizes transport in many natural and artificial devices, such as ionic channels, zeolites, and nanopores. While extensive theoretical and numerical studies on this subject have produced many important predictions, experimental verifications of the predictions are rare. Here, we experimentally measure colloidal diffusion times in microchannels with periodically varying width and contrast results with predictions from the Fick–Jacobs theory and Brownian dynamics simulation. While the theory and simulation correctly predict the entropic effect of the varying channel width, they fail to account for hydrodynamic effects, which include both an overall decrease and a spatial variation of diffusivity in channels. Neglecting such hydrodynamic effects, the theory and simulation underestimate the mean and standard deviation of first passage times by 40% in channels with a neck width twice the particle diameter. We further show that the validity of the Fick–Jacobs theory can be restored by reformulating it in terms of the experimentally measured diffusivity. Our work thus shows that hydrodynamic effects play a key role in diffusive transport through narrow channels and should be included in theoretical and numerical models.

Detection of viruses by electron microscopy: Increased sensitivity by direct micro-ultracentrifugation of samples

1987 ◽  
Vol 45 ◽  
pp. 908-909
Author(s):  
Alain R. Trudel ◽  
M. Trudel
Keyword(s):  
Electron Microscopy ◽  
Fold Increase ◽  
Observation Time ◽  
Clinical Samples ◽  
Maximum Speed ◽  
Viral Particles ◽  
Structural Details ◽  
Latex Spheres ◽  
Increased Sensitivity ◽  
Size Of Particles

AirfugeR (Beckman) direct ultracentrifugation of viral samples on electron microscopy grids offers a rapid way to concentrate viral particles or subunits and facilitate their detection and study. Using the A-100 fixed angle rotor (30°) with a K factor of 19 at maximum speed (95 000 rpm), samples up to 240 μl can be prepared for electron microscopy observation in a few minutes: observation time is decreased and structural details are highlighted. Using latex spheres to calculate the increase in sensitivity compared to the inverted drop procedure, we obtained a 10 to 40 fold increase in sensitivity depending on the size of particles. This technique also permits quantification of viral particles in samples if an aliquot is mixed with latex spheres of known concentration.Direct ultracentrifugation for electron microscopy can be performed on laboratory samples such as gradient or column fractions, infected cell supernatant, or on clinical samples such as urine, tears, cephalo-rachidian liquid, etc..

Fabrication of 2D Bravais Nano Pattern and Growth of ZnO Nano Rods with Photonic Crystal Effect

2011 ◽  
Vol 21 (12) ◽  
pp. 697-702
Author(s):  
Tae-Un Kim ◽  
Jong-Ha Moon ◽  
Seon-Hoon Kim ◽  
Doo-Gun Kim ◽  
Jin-Hyeok Kim
Keyword(s):  
Photonic Crystal ◽  
Nano Rods

Investigating the potential of redundant manipulators in narrow channels

2020 ◽  
pp. 095440622096451
Author(s):  
Ashish Singla ◽  
Jyotindra Narayan ◽  
Himanshu Arora
Keyword(s):  
Case Studies ◽  
Fuzzy Inference ◽  
Redundant Manipulators ◽  
Redundancy Resolution ◽  
Inference System ◽  
Narrow Channels ◽  
First Case ◽  
Task Priority ◽  
Patient Side

In this paper, an attempt has been made to investigate the potential of redundant manipulators, while tracking trajectories in narrow channels. The behavior of redundant manipulators is important in many challenging applications like under-water welding in narrow tanks, checking the blockage in sewerage pipes, performing a laparoscopy operation etc. To demonstrate this snake-like behavior, redundancy resolution scheme is utilized using two different approaches. The first approach is based on the concept of task priority, where a given task is split and prioritize into several subtasks like singularity avoidance, obstacle avoidance, torque minimization, and position preference over orientation etc. The second approach is based on Adaptive Neuro Fuzzy Inference System (ANFIS), where the training is provided through given datasets and the results are back-propagated using augmentation of neural networks with fuzzy logics. Three case studies are considered in this work to demonstrate the redundancy resolution of serial manipulators. The first case study of 3-link manipulator is attempted with both the approaches, where the objective is to track the desired trajectory while avoiding multiple obstacles. The second case study of 7-link manipulator, tracking trajectory in a narrow channel, is investigated using the concept of task priority. The realistic application of minimum-invasive surgery (MIS) based trajectory tracking is considered as the third case study, which is attempted using ANFIS approach. The 5-link spatial redundant manipulator, also known as a patient-side manipulator being developed at CSIR-CSIO, Chandigarh is used to track the desired surgical cuts. Through the three case studies, it is well demonstrated that both the approaches are giving satisfactory results.

scholarly journals Tailoring Properties of Resol Resin-Derived Spherical Carbons for Adsorption of Phenol from Aqueous Solution

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1736
Author(s):  
Karol Sidor ◽  
Tomasz Berniak ◽  
Piotr Łątka ◽  
Anna Rokicińska ◽  
Marek Michalik ◽  
...  
Keyword(s):  
Surface Composition ◽  
Micropore Volume ◽  
Gaseous Ammonia ◽  
Poly Vinyl Alcohol ◽  
Clear Correlation ◽  
Hno3 Solution ◽  
Synthesis Conditions ◽  
Adsorption Of Nitrogen ◽  
Oxygen Groups ◽  
Size Of Particles

The polycondensation of resorcinol and formaldehyde in a water–ethanol mixture using the adapted Stöber method was used to obtain resol resins. An optimization of synthesis conditions and the use of an appropriate stabilizer (e.g., poly(vinyl alcohol)) resulted in spherical grains. The resins were carbonized in the temperature range of 600–1050 °C and then chemically activated in an aqueous HNO3 solution, gaseous ammonia, or by an oxidation–reduction cycle (soaking in a HNO3 solution followed by treatment with NH3). The obtained carbons were characterized by XRD, the low-temperature adsorption of nitrogen, SEM, TGA, and XPS in order to determine degree of graphitization, porosity, shape and size of particles, and surface composition, respectively. Finally, the materials were tested in phenol adsorption. The pseudo-second order model perfectly described the adsorption kinetics. A clear correlation between the micropore volume and the adsorption capacity was found. The content of graphite domains also had a positive effect on the adsorption properties. On the other hand, the presence of heteroatoms, especially oxygen groups, resulted in the clogging of the pores and a decrease in the amount of adsorbed phenol.

scholarly journals Thermal Behaviour of Common Thermoresponsive Polymers in Phosphate Buffer and in Its Salt Solutions

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 90
Author(s):  
Łukasz Otulakowski ◽  
Maciej Kasprów ◽  
Aleksandra Strzelecka ◽  
Andrzej Dworak ◽  
Barbara Trzebicka
Keyword(s):  
Thermal Behaviour ◽  
Phosphate Buffer ◽  
Pure Water ◽  
Thermal Response ◽  
The Body ◽  
Solution Temperature ◽  
Thermoresponsive Polymers ◽  
Aqueous Polymer ◽  
Cloud Point Temperature ◽  
Size Of Particles

Thermoresponsive polymers are a promising material for drug nanocarrier preparation, which makes the study of their aggregation in physiological conditions very important. In this paper, the thermal behaviour of the thermoresponsive polymers poly(N-isopropylacrylamide), poly(2-isopropyl-2-oxazoline-co-2-n-propyl-2-oxazoline) and poly[(2-hydroxyethyl methacrylate)-co-oligo(ethylene glycol) methyl ether methacrylate] were studied in phosphate buffer (PBS) and solutions of its salts in concentration as in PBS. The thermal response of the polymers was measured using UV-Vis and dynamic light scattering (DLS). The salts shifted the cloud point temperature (TCP) of the (co)polymers to higher values compared to the TCP of aqueous polymer solutions. In PBS and NaCl solutions, all polymers exhibited an unexpected and previously unreported transmittance profile. During heating, an additional aggregation of polymers appeared above the TCP accompanied by the formation of a precipitate. In monosodium phosphate solutions and pure water, the studied polymers showed lower critical solution temperature (LCST-type) behaviour. DLS measurements showed that a salt influenced the size of the resulting polymer particles. The sizes and stability of particles depended on the heating rate. In PBS and NaCl solutions, the size of particles in the dispersion decreased above 60 °C, and the precipitate appeared on the bottom of the cuvette. The additional aggregation of polymer and its falling out of solution may hinder the removal of carriers from the body and has to be taken into account when preparing nanocarriers.

scholarly journals Theoretical Studies of the Interaction between Screw Surface and Material in the Mixer

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 962
Author(s):  
Andrzej Marczuk ◽  
Vasily Sysuev ◽  
Alexey Aleshkin ◽  
Petr Savinykh ◽  
Nikolay Turubanov ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
High Efficiency ◽  
Animal Feed ◽  
Structural Features ◽  
Power Demand ◽  
Friction Coefficients ◽  
Length Unit ◽  
Mixing Chamber ◽  
Size Of Particles ◽  
The Impact

Mixing is one of the most commonly used processes in food, animal feed, chemical, cosmetic, etc., industries. It is supposed to provide high-quality homogenous, nutritious mixtures. To provide appropriate mixing of materials while maintaining the process high efficiency and low energy consumption it is crucial to explore and describe the material flow caused by the movement of mixing elements and the contact between particles. The process of mixing is also affected by structural features of the machine components and the mixing chamber, speed of mixing, and properties of the mixed materials, such as the size of particles, moisture, friction coefficients. Thus, modeling of the phenomena that accompany the process of mixing using the above-listed parameters is indispensable for appropriate implementation of the process. The paper provides theoretical power calculations that take into account the material speed change, the impact of the material friction coefficient on the screw steel surface and the impact of the friction coefficient on the material, taking into account the loading height of the mixing chamber and the chamber loading value. Dependencies between the mixer power and the product degree of fineness, rotational speed of screw friction coefficients, the number of windings per length unit, and width of the screw tape have been presented on the basis of a developed model. It has been found that power increases along with an increase in the value of these parameters. Verification of the theoretical model indicated consistence of the predicted power demand with the power demand determined in tests performed on a real object for values of the assumed, effective loading, which was 65–75%.

Flowerlike hierarchical SAPO-5 molecular sieve composed of loosely aggregating uniformly primary nano-rods-like AFI crystals

2021 ◽  
pp. 138330
Author(s):  
Quanhua Wang ◽  
Sai Li ◽  
Yanchao Liu ◽  
Lichen Zhang ◽  
Jiajun Zheng ◽  
...  
Keyword(s):  
Molecular Sieve ◽  
Nano Rods
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