Influence of Particle Size, Applied Compression, and Substratum Material on Particle−Surface Adhesion Force Using the Centrifuge Technique

2009 ◽  
Vol 48 (2) ◽  
pp. 877-887 ◽  
Author(s):  
Marcos A. Felicetti ◽  
Giancarlo R. Salazar-Banda ◽  
José R. Coury ◽  
Mônica L. Aguiar
Keyword(s):  
Particle Size ◽  
Adhesion Force ◽  
Particle Surface ◽  
Surface Adhesion

Centrifuge Study on Influence of Particle Size, Compression and Substratum on Particle-Surface Adhesion Force

2008 ◽  
Vol 591-593 ◽  
pp. 347-351 ◽  
Author(s):  
M.A. Felicetti ◽  
José Renato Coury ◽  
M.L. Aguiar
Keyword(s):  
Particle Size ◽  
Phosphate Rock ◽  
Adhesion Force ◽  
Rotation Speed ◽  
Particle Surface ◽  
Particle Sizes ◽  
Adhesion Forces ◽  
Surface Adhesion ◽  
Log Normal ◽  
Log Normal Distribution

The centrifugal technique was used to investigate the influence of particle size, applied compression and substrate materials (stainless steel, glass, Teflon® and PVC) on particle-surface adhesion force. Phosphate rock and manioc starch particles were used in a microcentrifuge that contained specially designed centrifuge tubes and reached a maximum rotation speed of 14,000 rpm. The profile of adhesion force followed a log-normal distribution and adhesion force increased linearly with particle size and the increment of the compression force. The manioc starch particles presented adhesion forces greater than those for the phosphate rock particles for all particle sizes studied. The glass substrate showed a higher adherence than other materials, most probably due to its hardness and polishing.

scholarly journals Ice nucleation abilities of soot particles determined with the Horizontal Ice Nucleation Chamber

2018 ◽  
Vol 18 (18) ◽  
pp. 13363-13392 ◽  
Author(s):  
Fabian Mahrt ◽  
Claudia Marcolli ◽  
Robert O. David ◽  
Philippe Grönquist ◽  
Eszter J. Barthazy Meier ◽  
...  
Keyword(s):  
Particle Size ◽  
Water Saturation ◽  
Particle Surface ◽  
Water Vapor Sorption ◽  
Contact Angles ◽  
Ice Nucleation ◽  
Particle Surface Area ◽  
Soot Particles ◽  
Microphysical Properties ◽  
Homogeneous Freezing

Abstract. Ice nucleation by different types of soot particles is systematically investigated over the temperature range from 218 to 253 K relevant for both mixed-phase (MPCs) and cirrus clouds. Soot types were selected to represent a range of physicochemical properties associated with combustion particles. Their ice nucleation ability was determined as a function of particle size using relative humidity (RH) scans in the Horizontal Ice Nucleation Chamber (HINC). We complement our ice nucleation results by a suite of particle characterization measurements, including determination of particle surface area, fractal dimension, temperature-dependent mass loss (ML), water vapor sorption and inferred porosity measurements. Independent of particle size, all soot types reveal absence of ice nucleation below and at water saturation in the MPC regime (T>235 K). In the cirrus regime (T≤235 K), soot types show different freezing behavior depending on particle size and soot type, but the freezing is closely linked to the soot particle properties. Specifically, our results suggest that if soot aggregates contain mesopores (pore diameters of 2–50 nm) and have sufficiently low water–soot contact angles, they show ice nucleation activity and can contribute to ice formation in the cirrus regime at RH well below homogeneous freezing of solution droplets. We attribute the observed ice nucleation to a pore condensation and freezing (PCF) mechanism. Nevertheless, soot particles without cavities of the right size and/or too-high contact angles nucleate ice only at or well above the RH required for homogeneous freezing conditions of solution droplets. Thus, our results imply that soot particles able to nucleate ice via PCF could impact the microphysical properties of ice clouds.

scholarly journals Effect of Home Grinding on Properties of Brewed Coffee

2014 ◽  
Vol 4 (1) ◽  
pp. 77
Author(s):  
Christopher Murray ◽  
Thamara Laredo
Keyword(s):  
Particle Size ◽  
Fourier Transform ◽  
Distribution Density ◽  
Particle Surface ◽  
Particle Surface Area ◽  
Present Evidence ◽  
Caffeine Content ◽  
General Recommendation ◽  
Grinding Time ◽  
Ground Coffee

<p>We present measurements of particle size distribution, density, loss of coffee on brewing and caffeine content in brewed coffee (as measured using Fourier Transform Infrared Spectroscopy) as a function of grinding time using a blade-type grinder. In general, there is not a lack of correlation between coffee properties and grinding for grinding times in excess of 42 s, but mass loss on brewing and caffeine content are both increased with grinding times between 0 and 42 s. In addition, we present evidence that this dependence of the composition of brewed coffee on grinding time is a function of increased coffee particle surface area that results from grinding, rather than increased loss of grounds into the brewed beverage or increased percolation time. Finally, we present a general recommendation for determining equivalency between small amounts of finely ground coffee and larger amounts of coarser-ground coffee.</p>

scholarly journals On the contribution of Aitken mode particles to cloud droplet populations at continental background areas – a parametric sensitivity study

2007 ◽  
Vol 7 (3) ◽  
pp. 6077-6112
Author(s):  
T. Anttila ◽  
V.-M. Kerminen
Keyword(s):  
Surface Tension ◽  
Particle Size ◽  
Chemical Composition ◽  
Pure Water ◽  
Particle Surface ◽  
Chemical Properties ◽  
Sensitivity Study ◽  
Geometric Standard Deviation ◽  
Cloud Droplets ◽  
Aitken Mode

Abstract. Aitken mode particles are potentially an important source of cloud droplets in continental background areas. In order to find out which physico-chemical properties of Aitken mode particles are most important regarding their cloud-nucleating ability, we applied a global sensitivity method to an adiabatic air parcel model simulating the number of cloud droplets formed on Aitken mode particles, CD2. The technique propagates uncertainties in the parameters describing the properties of Aitken mode to CD2. The results show that if the Aitken mode particles do not contain molecules that are able to reduce the particle surface tension more than 30% and/or decrease the mass accommodation coefficient of water, α, below 10−2, the chemical composition and modal properties may have roughly an equal importance at low updraft velocities characterized by maximum supersaturations <0.1%. For larger updraft velocities, however, the particle size distribution is clearly more important than the chemical composition. In general, CD2 exhibits largest sensitivity to the particle number concentration, followed by the particle size. Also the shape of the particle mode, characterized by the geometric standard deviation (GSD), can be as important as the mode mean size at low updraft velocities. Finally, the performed sensitivity analysis revealed also that the chemistry may dominate the total sensitivity of CD2 to the considered parameters if: 1) the value of α varies at least one order of magnitude more than what is expected for pure water surfaces (10−2–1), or 2) the particle surface tension varies more than roughly 30% under conditions close to reaching supersaturation.

scholarly journals Effect of basic oxygen furnace slag particle size on sequestration of carbon dioxide from landfill gas

2019 ◽  
Vol 37 (5) ◽  
pp. 469-477 ◽  
Author(s):  
Krishna R. Reddy ◽  
Archana Gopakumar ◽  
Raksha K. Rai ◽  
Girish Kumar ◽  
Jyoti K. Chetri ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Particle Size ◽  
Inner Core ◽  
Landfill Gas ◽  
Particle Surface ◽  
Basic Oxygen Furnace ◽  
Column Experiments ◽  
Basic Oxygen ◽  
Slag Particle ◽  
Bof Slag

The mineral carbon sequestration capacity of basic oxygen furnace (BOF) slag offers great potential to absorb carbon dioxide (CO2) from landfill emissions. The BOF slag is highly alkaline and rich in calcium (Ca) containing minerals that can react with the CO2 to form stable carbonates. This property of BOF slag makes it appealing for use in CO2 sequestration from landfill gas. In a previous study, CO2 and CH4 removal from the landfill gas was investigated by performing batch and column experiments with BOF slag under different moisture and synthetic landfill gas exposure conditions. The study showed two stage CO2 removal mechanism: (1) initial rapid CO2 removal, which was attributed to the carbonation of free lime (CaO) and portlandite [(Ca(OH)2)], and (2) long-term relatively slower CO2 removal, which was attributed to be the gradual leaching of Ca2+ from minerals (calcium-silicates) present in the BOF slag. Realising that the particle size could be an important factor affecting total CO2 sequestration capacity, this study investigates the effect of gradation on the CO2 sequestration capacity of the BOF slag under simulated landfill gas conditions. Batch and column experiments were performed with BOF slag using three gradations: (1) coarse (D50 = 3.05 mm), (2) original (D50 = 0.47 mm), and (3) fine (D50 = 0.094 mm). The respective CO2 sequestration potentials attained were 255 mg g−1, 155 mg g−1, and 66 mg g−1. The highest CO2 sequestration capacity of fine BOF slag was attributed to the availability of calcium containing minerals on the slag particle surface owing to the highest surface area and shortest leaching path for the Ca2+ from the inner core of the slag particles.

scholarly journals Molecular Recognition and Cell Surface Biochemical Response of Bacillus thuringiensis on Triphenyltin

Processes ◽  
2019 ◽  
Vol 7 (6) ◽  
pp. 358
Author(s):  
Hongling Zhang ◽  
Jinshao Ye ◽  
Huaming Qin ◽  
Xujun Liang ◽  
Yan Long
Keyword(s):  
Bacillus Thuringiensis ◽  
Molecular Recognition ◽  
Cell Surface ◽  
Adhesion Force ◽  
Tween 80 ◽  
Cell Permeability ◽  
Surface Adhesion ◽  
Force Microscopy ◽  
Growth Status ◽  
Atomic Force

Triphenyltin (TPT) has severely polluted the environment, and it often coexists with metal ions, such as Cu2+. This paper describes the cell’s molecular recognition of TPT, the interaction between TPT recognition and Cu2+ biosorption, and their effect on cell permeability. We studied the recognition of TPT by Bacillus thuringiensis cells and the effect of TPT recognition on Cu2+ biosorption by using atomic force microscopy to observe changes in cell surface mechanical properties and cellular morphology and by using flow cytometry to determine the cell growth status and cell permeability. The results show that B. thuringiensis can quickly recognize different media. The adhesion force of cells in contact with Tween 80 was significantly reduced to levels that were much lower than that of cells in contact with PBS. Conversely, the cell surface adhesion force increased as TPT became more degraded. B. thuringiensis cells maintained their original morphology after 48 h of TPT treatment. The amount of Cu2+ adsorption by TPT-treated cells was positively correlated with the surface adhesion force (r = 0.966, P = 0.01). The cell adhesion force significantly decreased after Cu2+ adsorption, and cell recognition of TPT and/or Cu2+ hindered the entrance of 2’,7’-dichlorodihydrofluorescein diacetate (DCFH-DA) into the cell. The initial diffusion time of DCFH-DA into cells treated by PBS, Cu2+, TPT, and TPT+Cu2+ was 4, 10, 30, and 30 min, respectively, and the order of the fluorescence intensity was PBS >> Cu2+ > TPT > TPT+Cu2+. We conclude that changes in the cell surface properties of the microbe during recognition of pollutants depend on the contaminant’s properties. B. thuringiensis recognized TPT and secreted intracellular substances that not only enhanced the adsorption of Cu2+, but also formed a “barrier” on the cell surface that reduced permeability. These findings provide a novel insight into the mechanism of microbial removal of pollutants.

scholarly journals Nanoscale mapping of dielectric properties based on surface adhesion force measurements

2018 ◽  
Vol 9 ◽  
pp. 900-906 ◽  
Author(s):  
Ying Wang ◽  
Yue Shen ◽  
Xingya Wang ◽  
Zhiwei Shen ◽  
Bin Li ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Dielectric Properties ◽  
Adhesion Force ◽  
Model Systems ◽  
Adhesion Forces ◽  
Surface Adhesion ◽  
Storage Devices ◽  
Force Microscopy ◽  
Atomic Force

The detection of local dielectric properties is of great importance in a wide variety of scientific studies and applications. Here, we report a novel method for the characterization of local dielectric distributions based on surface adhesion mapping by atomic force microscopy (AFM). The two-dimensional (2D) materials graphene oxide (GO), and partially reduced graphene oxide (RGO), which have similar thicknesses but large differences in their dielectric properties, were studied as model systems. Through direct imaging of the samples with a biased AFM tip in PeakForce Quantitative Nano-Mechanics (PF-QNM) mode, the local dielectric properties of GO and RGO were revealed by mapping their surface adhesion forces. Thus, GO and RGO could be conveniently differentiated. This method provides a simple and general approach for the fast characterization of the local dielectric properties of graphene-based materials and will further facilitate their applications in energy generation and storage devices.

scholarly journals Size dependent efficiency of photophoretic swimmers

2015 ◽  
Vol 184 ◽  
pp. 381-391 ◽  
Author(s):  
Andreas P. Bregulla ◽  
Frank Cichos
Keyword(s):  
Particle Size ◽  
Laser Power ◽  
Symmetry Axis ◽  
Particle Surface ◽  
Finite Size ◽  
Optical Power ◽  
Surface Flow ◽  
Incident Laser ◽  
Size Dependent ◽  
Incident Laser Power

We investigate experimentally the efficiency of self-propelled photophoretic swimmers based on metal-coated polymer particles of different sizes. The metal hemisphere absorbs the incident laser power and converts its energy into heat, which dissipates into the environment. A phoretic surface flow arises from the temperature gradient along the particle surface and drives the particle parallel to its symmetry axis. Scaling the particle size from micro to nanometers, the efficiency of converting optical power into motion is expected to rise with the reciprocal size for ideal swimmers. However, due to the finite size of the metal cap, the efficiency of a real swimmer reveals a maximum depending sensitively on the details of the metal cap shape. We compare the experimental results to numerical simulations.

Developments for Physical Cleaning Sample with High Adhesion Force Particles and Direct Measurement of its Removal Force

2016 ◽  
Vol 255 ◽  
pp. 201-206 ◽  
Author(s):  
Emu Tokuda ◽  
Toshiyuki Sanada ◽  
Futoshi Iwata ◽  
Chikako Takato ◽  
Hirokuni Hiyama ◽  
...  
Keyword(s):  
Particle Size ◽  
Direct Measurement ◽  
Adhesion Force ◽  
Removal Rate ◽  
Particle Removal ◽  
Cleaning Performance ◽  
High Adhesion ◽  
Particle Adhesion Force ◽  
Particle Sample ◽  
Measured Particle

We quantitatively evaluate the wet cleaning performance of particle cotamination. We made particle sample which endure the wet cleaning and measured particle adhesion force by self-sensitive cantilever. The advantage of this method is that performed in both air and water. As a result, there were no significant differences between the air and water condition and the influence of particle size were dominant. Using this sample, we demonstrated particle removal rate of droplets impacts and PVA brush.

Sign in / Sign up

Export Citation Format

Share Document