Optical technique for measuring the positive and negative dielectrophoretic behaviour of cells and colloidal suspensions

1994 ◽  
Vol 141 (5) ◽  
pp. 395-399 ◽  
Author(s):  
M.S. Talary ◽  
R. Pethig
Keyword(s):  
Colloidal Suspensions ◽  
Optical Technique

A metal- coating Chamber for High-Resolution Cryo-SEM

1990 ◽  
Vol 48 (1) ◽  
pp. 418-419
Author(s):  
John G. Sheehan
Keyword(s):  
High Resolution ◽  
Colloidal Suspensions ◽  
Metal Coating ◽  
Colloidal Interactions ◽  
Amorphous Ice ◽  
High Vapor ◽  
Particulate Coatings ◽  
20 Nm ◽  
Film Nucleation ◽  
Coating Chamber

Improvements in particulate coatings for printable paper require understanding mechanisms of colloidal interactions in paper coating suspensions. One way to deduce colloidal interactions is to mage particle spacings and orientations at high resolution with cryo-SEM. Recent improvements in cryo-SEM technique have increased resolution enough to image particles in coating paints,vhich are sometimes smaller than 100 nm. In this report, a metal-coating chamber is described for preparation of colloidal suspensions for cryo-SEM at resolution down to 20 nm. It was found that etching is not necessary to achieve this resolution.A 120 K cryo-SEM sample will remain in an SEM for hours without noticeable condensation of imorphous ice. This is due to the high vapor pressure of vapor-condensed amorphous ice, measured by Kouchi. However, clean vacuum is required to coat samples with the thinnest possible continuous metal films which are required for high magnification SEM. Vapor contaminants, especially hrydrocarbons, are known to interfere with thin-film nucleation and growth so that more metal is needed to form continuous films, and resolution is decreased. That is why the metal-coating chamber in fig. 1 is designed for the cleanest possible vacuum. Feedthroughs for the manipulator md the shutter, which are operated during metal coating, are sealed with leak-proof stainless-steel Dellows. The transfer rod slides through a baseplate feedthrough that is double o-ring sealed.

Growth Kinetics of Quantum Size ZnO Particles

1998 ◽  
Vol 536 ◽  
Author(s):  
E. M. Wong ◽  
J. E. Bonevich ◽  
P. C. Searson
Keyword(s):  
Growth Kinetics ◽  
Ostwald Ripening ◽  
Chemical Potential ◽  
Colloidal Suspensions ◽  
Green Emission ◽  
Blue Shift ◽  
Constant Current ◽  
Mass Model ◽  
Zno Particles ◽  
Kinetics Of

AbstractColloidal chemistry techniques were used to synthesize ZnO particles in the nanometer size regime. The particle aging kinetics were determined by monitoring the optical band edge absorption and using the effective mass model to approximate the particle size as a function of time. We show that the growth kinetics of the ZnO particles follow the Lifshitz, Slyozov, Wagner theory for Ostwald ripening. In this model, the higher curvature and hence chemical potential of smaller particles provides a driving force for dissolution. The larger particles continue to grow by diffusion limited transport of species dissolved in solution. Thin films were fabricated by constant current electrophoretic deposition (EPD) of the ZnO quantum particles from these colloidal suspensions. All the films exhibited a blue shift relative to the characteristic green emission associated with bulk ZnO. The optical characteristics of the particles in the colloidal suspensions were found to translate to the films.

Numerical Study of the Structure and Thermodynamics of Colloidal Suspensions by Variational Method

2014 ◽  
pp. 12-26
Author(s):  
Khalid Elhasnaoui ◽  
◽  
A. Maarouf ◽  
M. Badia ◽  
M. Benhamou ◽  
...  
Keyword(s):  
Variational Method ◽  
Numerical Study ◽  
Colloidal Suspensions

Antimicrobial Colloidal Suspensions of Silver-Titania

2009 ◽  
Vol 2 (3) ◽  
pp. 77-85 ◽  
Author(s):  
Stefania Gavriliu ◽  
Magdalena Lungu ◽  
Liana C. Gavriliu ◽  
Florentina Grigore ◽  
Claudia Groza
Keyword(s):  
Colloidal Suspensions

scholarly journals Contact and macroscopic ageing in colloidal suspensions

2020 ◽  
Vol 19 (7) ◽  
pp. 775-780 ◽  
Author(s):  
Francesco Bonacci ◽  
Xavier Chateau ◽  
Eric M. Furst ◽  
Jennifer Fusier ◽  
Julie Goyon ◽  
...  
Keyword(s):  
Colloidal Suspensions

scholarly journals Reentrant Phase Transition in Charged Colloidal Suspensions

1988 ◽  
Vol 60 (23) ◽  
pp. 2438-2441 ◽  
Author(s):  
Akhilesh K. Arora ◽  
B. V. R. Tata ◽  
A. K. Sood ◽  
R. Kesavamoorthy
Keyword(s):  
Phase Transition ◽  
Colloidal Suspensions

scholarly journals Nanoencapsulated Essential Oils with Enhanced Antifungal Activity for Potential Application on Agri-Food, Material and Environmental Fields

Antibiotics ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 31
Author(s):  
Magdaléna Kapustová ◽  
Giuseppe Granata ◽  
Edoardo Napoli ◽  
Andrea Puškárová ◽  
Mária Bučková ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Essential Oil ◽  
Essential Oils ◽  
Winning Strategy ◽  
Colloidal Suspensions ◽  
Fungal Species ◽  
Natural Environments ◽  
Food Material ◽  
Minimum Fungicidal Concentration ◽  
Fungal Strains

Nanotechnology is a new frontier of this century that finds applications in various fields of science with important effects on our life and on the environment. Nanoencapsulation of bioactive compounds is a promising topic of nanotechnology. The excessive use of synthetic compounds with antifungal activity has led to the selection of resistant fungal species. In this context, the use of plant essential oils (EOs) with antifungal activity encapsulated in ecofriendly nanosystems could be a new and winning strategy to overcome the problem. We prepared nanoencapsules containing the essential oils of Origanum vulgare (OV) and Thymus capitatus (TC) by the nanoprecipitation method. The colloidal suspensions were characterized for size, polydispersity index (PDI), zeta potential, efficiency of encapsulation (EE) and loading capacity (LC). Finally, the essential oil nanosuspensions were assayed against a panel of fourteen fungal strains belonging to the Ascomycota and Basidiomycota phyla. Our results show that the nanosystems containing thyme and oregano essential oils were active against various fungal strains from natural environments and materials. In particular, the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) values were two to four times lower than the pure essential oils. The aqueous, ecofriendly essential oil nanosuspensions with broad-spectrum antifungal activity could be a valid alternative to synthetic products, finding interesting applications in the agri-food and environmental fields.

scholarly journals Detection of the TiO2 Concentration in the Protective Coatings for the Cultural Heritage by Means of Hyperspectral Data

2020 ◽  
Vol 13 (1) ◽  
pp. 92
Author(s):  
Antonio Costanzo ◽  
Donatella Ebolese ◽  
Silvestro Antonio Ruffolo ◽  
Sergio Falcone ◽  
Carmelo la Piana ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Cultural Heritage ◽  
Urban Areas ◽  
Protective Coatings ◽  
Colloidal Suspensions ◽  
Hyperspectral Data ◽  
Weight Percentage ◽  
Stone Materials ◽  
Test Application ◽  
Nanoparticle Coatings

Nanotechnology-based materials are currently being tested in the protection of cultural heritage: ethyl silicate or silica nanoparticles dispersed in aqueous colloidal suspensions mixed with titanium dioxide are used as a coating for stone materials. These coatings can play a key role against the degradation of stone materials, due to the deposit of organic matter and other contaminants on the substrate, a phenomenon that produces a greater risk for the monuments in urban areas because of the increasing atmospheric pollution. However, during the application phase, it is important to evaluate the amount of titanium dioxide in the coatings on the substrate, as it can produce a coverage effect on the asset. In this work, we present the hyperspectral data obtained through a field spectroradiometer on samples of different stone materials, which have been prepared in laboratory with an increasing weight percentage of titanium dioxide from 0 to 8 wt%. The data showed spectral signatures dependent on the content of titanium dioxide in the wavelength range 350–400 nm. Afterwards, blind tests were performed on other samples in order to evaluate the reliability of these measurements in detecting the unknown weight percentage of titanium dioxide. Moreover, an investigation was also performed on a test application of nanoparticle coatings on a stone statue located in a coastal town in Calabria (southern Italy). The results showed that the surveys can be useful for verifying the phase of application of the coating on cultural heritage structures; however, they could also be used to check the state of the coated stone directly exposed over time to atmospheric, biological and chemical agents.

scholarly journals Air bubbles play a role in shear thinning of non-colloidal suspensions

2021 ◽  
Vol 33 (1) ◽  
pp. 011702
Author(s):  
Yuan Lin ◽  
Ying Wang ◽  
Zixin Weng ◽  
Dingyi Pan ◽  
Jiawang Chen
Keyword(s):  
Colloidal Suspensions ◽  
Shear Thinning ◽  
Air Bubbles
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