Effect of Home Grinding on Properties of Brewed 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>

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

Atmospheric Chemistry and Physics ◽

10.5194/acp-18-13363-2018 ◽

2018 ◽

Vol 18 (18) ◽

pp. 13363-13392 ◽

Cited By ~ 25

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.

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INFLUENCE OF PARTICLE SIZE ON THE DYNAMIC STRENGTH OF ELECTRORHEOLOGICAL FLUIDS

International Journal of Modern Physics B ◽

10.1142/s0217979294001160 ◽

1994 ◽

Vol 08 (20n21) ◽

pp. 2835-2853 ◽

Cited By ~ 35

Author(s):

YUNG-HUI SHIH ◽

HANS CONRAD

Keyword(s):

Particle Size ◽

Electric Field ◽

Volume Fraction ◽

Low Voltage ◽

Silicone Oil ◽

Particle Surface ◽

Dynamic Strength ◽

Columnar Structure ◽

Particle Surface Area ◽

Polarization Component

The electrical properties, rheology and structure of model ER fluids consisting of glass beads in silicone oil were investigated as a function of electric field E (0–4 kV/mm ), particle size D (6–100 µ m ) and shear rate [Formula: see text]. The conductivity of the suspensions was 3 orders of magnitude greater than that of the host oil at E ⋝ 1 kV/mm ; their low-voltage d.c. permittivity was about 1.35 times larger. The flow stress of the suspensions was given by [Formula: see text] where τE is the polarization component and τ vis the viscous component. The linear dependence of τE on E was attributed to dipole saturation. The observed opposing effects of D and [Formula: see text] on τE were concluded to result from their respective influence on the strength of the columnar structure normally produced by the electric field and its fragmentation during shear. The constant C1 was in agreement with the Einstein equation for the effect of volume fraction of particles on the viscosity of suspensions. The parameter C2/D was concluded to reflect either the effect of particle surface area on viscosity or a polydispersion effect. The present results did not correlate with the Mason number as normally formulated, but did when it was appropriately modified.

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Relationship Between Particle Size Distribution and Specific Surface Area of Urban Roadway Stormwater Solids

Transportation Research Record Journal of the Transportation Research Board ◽

10.3141/1601-15 ◽

1997 ◽

Vol 1601 (1) ◽

pp. 95-108 ◽

Cited By ~ 5

Author(s):

John J. Sansalone ◽

Steven G. Buchberger ◽

Joseph M. Koran ◽

Joseph A. Smithson

Keyword(s):

Particle Size ◽

Specific Surface ◽

Surface Area ◽

Particle Surface ◽

Chemical Properties ◽

Spherical Particles ◽

Particle Surface Area ◽

Surface Areas ◽

Physical And Chemical ◽

And Chemical Properties

Surface area is a primary factor in determining many physical and chemical properties of solids, especially particles. In urban and highway runoff, solids can mediate the partitioning between the dissolved and particulate-bound phases of metal elements and organic compounds. Solids are also capable of adversely affecting roadway drainage appurtenances through sedimentation and clogging. Solids characteristics of primary importance for both solute adsorption and clogging and sedimentation are particle size distributions (PSDs), specific surface areas (SSAs), and mass loadings. PSD and SSA results are presented for rainfall and snowmelt solids from a heavily traveled urban roadway in Cincinnati. Integration of the PSD and SSA results indicates that particle surface area is greatest for the midrange (> 100 μm) to the coarser end (<2000 μm) of the gradation. SSA results determined using the assumption of smooth spherical particles are indicated to grossly underestimate actual SSA values.

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Nanocrystals of Poorly Soluble Drugs: Drug Bioavailability and Physicochemical Stability

10.20944/preprints201807.0233.v1 ◽

2018 ◽

Cited By ~ 1

Author(s):

Maria Rosa Gigliobianco ◽

Cristina Casadidio ◽

Roberta Censi ◽

Piera Di Martino

Keyword(s):

Particle Size ◽

Particle Surface ◽

Poorly Soluble Drugs ◽

Drug Bioavailability ◽

Particle Surface Area ◽

Drug Products ◽

Surface Active Agents ◽

Physicochemical Stability ◽

Poorly Soluble ◽

Surface Active

Many approaches have been developed over time to counter the bioavailability limitations of poorly soluble drugs. With advances in nanotechnology in recent decades, science and industry have been approaching this issue through the formulation of drugs as nanocrystals, which consist of pure drugs and a minimum of surface active agents required for stabilization. They are carrier-free submicron colloidal drug delivery systems with a mean particle size in the nanometer range, typically between 10 and 800 nm. By reducing particle size to nanoscale, the particle surface area available for the molecule dissolution in the direction of dissolution medium is increased, and thus bioavailability is enhanced. This approach has proven successful, as demonstrated by the number of such drug products on the market. R&D and industry have offered many technological solutions to reduce the particle size to nanoscale, and also devised solutions for the handling of particle of nanodimensions, such as methods to accurately measure nanoparticle size and techniques to prevent physicochemical and stability related problems, such as aggregation. The present work provides an overview of the more recent achievements in improving the bioavailability of poorly soluble drugs according to their administration route, and describes the methods developed to overcome physicochemical and stability related problems.

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

10.5194/acp-2018-557 ◽

2018 ◽

Cited By ~ 2

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, 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 behaviour 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.

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Total Surface Area Estimates for Individual Ice Particles and Particle Populations

Journal of Applied Meteorology ◽

10.1175/jam2209.1 ◽

2005 ◽

Vol 44 (4) ◽

pp. 467-474 ◽

Cited By ~ 12

Author(s):

C. G. Schmitt ◽

A. J. Heymsfield

Keyword(s):

Particle Size ◽

Particle Size Distribution ◽

Size Distribution ◽

Surface Area ◽

Particle Surface ◽

Total Surface Area ◽

Regional Study ◽

Particle Surface Area ◽

Projected Area ◽

Ice Particles

Abstract Representations for the surface area of ice particles in terms of the projected area have been developed using two different methods. The first method uses ice particles that are imaged in situ and geometric calculations that are based on the outline of the two-dimensional image of the particle. The second method uses computer-generated ice particle shapes and calculates the total surface area analytically. The results of the second method compare reasonably well with the results of the first method. Surface area estimates for individual particles were combined with particle size distribution and projected area measurements from the Cirrus Regional Study of Tropical Anvils and Cirrus Layers (CRYSTAL)–Florida Area Cirrus Experiment (FACE) field project to give total surface area estimates for observed ice particle populations. Population surface area estimates were also made from balloon-borne replicator data collected during the First International Satellite Cloud Climatology Project (ISCCP) Regional Experiment, phase II (FIRE-II). A relationship between the particle population surface area and projected area (cloud extinction) has been derived. The total particle surface area for particle populations is estimated to be between 8 and 10 times the projected area or between 4 and 5 times the extinction and has a small dependence on the properties of the particle size distribution for particles observed in random orientations.

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Quantities Directly Measurable by Scattering

10.1093/oso/9780199670871.003.0003 ◽

2018 ◽

Author(s):

Eaton E. Lattman ◽

Thomas D. Grant ◽

Edward H. Snell

Keyword(s):

Molecular Weight ◽

Particle Shape ◽

Particle Surface ◽

Scattering Data ◽

Radius Of Gyration ◽

Particle Volume ◽

Particle Surface Area ◽

Scattering Angle ◽

Particle Dimension ◽

Maximum Particle

In this chapter we note that solution scattering data can be divided into four regions. At zero scattering angle, the scattering provides information on molecular weight of the particle in solution. Beyond that, the scattering is influenced by the radius of gyration. As the scattering angle increases, the scattering is influenced by the particle shape, and finally by the interface with the particle and the solution. There are a number of important invariants that can be calculated directly from the data including molecular mass, radius of gyration, Porod invariant, particle volume, maximum particle dimension, particle surface area, correlation length, and volume of correlation. The meaning of these is described in turn along with their mathematical derivations.

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Changes of Pd Oxidation State in Pd/Al2O3 Catalysts Using Modulated Excitation DRIFTS

Catalysts ◽

10.3390/catal11010116 ◽

2021 ◽

Vol 11 (1) ◽

pp. 116

Author(s):

Gian Luca Chiarello ◽

Ye Lu ◽

Miren Agote-Arán ◽

Riccardo Pellegrini ◽

Davide Ferri

Keyword(s):

Particle Size ◽

Fourier Transform ◽

Infrared Spectroscopy ◽

Oxidation State ◽

Diffuse Reflectance ◽

X Ray ◽

Spectral Changes ◽

Diffuse Reflectance Infrared ◽

X Ray Absorption ◽

Reversible Reduction

Infrared spectroscopy is typically not used to establish the oxidation state of metal-based catalysts. In this work, we show that the baseline of spectra collected in diffuse reflectance mode of a series of Pd/Al2O3 samples of increasing Pd content varies significantly and reversibly under alternate pulses of CO or H2 and O2. Moreover, these baseline changes are proportional to the Pd content in Pd/Al2O3 samples exhibiting comparable Pd particle size. Similar measurements by X-ray absorption spectroscopy on a different 2 wt.% Pd/Al2O3 confirm that the baseline changes reflect the reversible reduction-oxidation of Pd. Hence, we demonstrate that changes in oxidation state of metal-based catalysts can be determined using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and that this behavior is part of the spectral changes that are returned by experiments under operando conditions.

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