THE DETERMINATION OF SURFACE AREAS ON TITANIUM DIOXIDE PIGMENTS

1970 ◽  
pp. 397-399 ◽  
Author(s):  
D. URWIN
Keyword(s):  
Titanium Dioxide ◽  
Surface Areas

scholarly journals Determination of Arsenic, Chromium and Lead in titanium dioxide pigments by ICP- OES with Concomitant Metals Analyser

2019 ◽  
pp. 296-305
Author(s):  
Beena Sunilkumar ◽  
S. B. Singh
Keyword(s):  
Titanium Dioxide ◽  
Matrix Effects ◽  
Mineral Acid ◽  
Icp Oes ◽  
Acid Decomposition ◽  
Simple Method ◽  
Sample Dissolution ◽  
The Matrix ◽  
Generating System

A simple method has been developed for the determination of trace toxic elements like arsenic, lead and chromium in titanium dioxide pigment samples by ICP OES attached with a Concomitant Metals Analyser. Open mineral acid decomposition was used for sample dissolution employing a mixture of nitric and hydrofluoric acids. The continuous online generation of hydrides into the plasma was achieved through a concomitant metals analyser. The recovery of arsenic, lead and chromium and the matrix effects of titanium on these elements have been studied with spiking experiments. The proposed method has been successfully applied to the determination of arsenic and other elements in titanium pigment samples. The continuous hydride generating system, Concomitant Metals Analyser (CMA) improved the sensitivity of analysis nearly five times in pigment samples. The precision of the measurements was found to be less than 10% RSD.

Studies on the surface area of zeolites, as determined by physical adsorption and X-ray crystallography

1968 ◽  
Vol 46 (10) ◽  
pp. 1695-1701 ◽  
Author(s):  
D. J. C. Yates
Keyword(s):  
Surface Area ◽  
Physical Adsorption ◽  
Independent Method ◽  
Linear Portion ◽  
Adsorbed Molecules ◽  
X Ray ◽  
X Ray Crystallography ◽  
Surface Areas

The determination of the surface areas of zeolites is discussed. It is shown that it is incorrect to use the multilayer isotherm method of Brunauer, Emmett, and Teller for solids where only little more than one monolayer can be adsorbed, in cavities little larger than the adsorbed molecules. The areas of such materials can, however, be determined from the beginning of the linear portion of their isotherms (point B). In addition, X-ray spectra can provide an independent method of measuring changes in the surface areas of zeolites.

Extremum Properties of the Regular Polyhedra

1950 ◽  
Vol 2 ◽  
pp. 22-31 ◽  
Author(s):  
Lâszlό Fejes Tόth
Keyword(s):  
Regular Polygons ◽  
Surface Areas ◽  
Extremum Problems ◽  
Regular Polyhedra ◽  
Historical Remarks

1. Historical remarks. In this paper we extend some well-known extremum properties of the regular polygons to the regular polyhedra. We start by mentioning some known results in this direction.First, let us briefly consider the problem which has received the greatest attention among all the extremum problems for polyhedra. It is the determination of the polyhedron of greatest volume F of a class of polyhedra of equal surface areas F, i.e., the isepiphan problem.

scholarly journals Monitoring of snow surface near-infrared bidirectional reflectance factors with added light-absorbing particles

2019 ◽  
Vol 13 (6) ◽  
pp. 1753-1766 ◽  
Author(s):  
Adam Schneider ◽  
Mark Flanner ◽  
Roger De Roo ◽  
Alden Adolph
Keyword(s):  
Near Infrared ◽  
Bidirectional Reflectance ◽  
Nondestructive Technique ◽  
Snow Albedo ◽  
Considerable Uncertainty ◽  
Clear Sky ◽  
Surface Areas ◽  
Microphysical Properties ◽  
Sky Conditions

Abstract. Broadband snow albedo can range from 0.3 to 0.9 depending on microphysical properties and light-absorbing particle (LAP) concentrations. Beyond the widely observed direct and visibly apparent effect of darkening snow, it is still unclear how LAPs influence snow albedo feedbacks. To investigate LAPs' indirect effect on snow albedo feedbacks, we developed and calibrated the Near-Infrared Emitting and Reflectance-Monitoring Dome (NERD) and monitored bidirectional reflectance factors (BRFs) hourly after depositing dust and black carbon (BC) particles onto experimental snow surfaces. After comparing snow infrared BRFs to snow specific surface areas (SSAs), we found that both measured and modeled snow infrared BRFs are correlated with snow SSA. These results, however, demonstrate a considerable uncertainty of ±10 m2 kg−1 in the determination of snow SSA from our BRF measurements. The nondestructive technique for snow SSA retrieval that we present here can be further developed for science applications that require rapid in situ snow SSA measurements. After adding large amounts of dust and BC to snow, we found more rapid decreasing of snow BRFs and SSAs in snow with added LAPs compared to natural (clean) snow but only during clear-sky conditions. These results suggest that deposition of LAPs onto snow can accelerate snow metamorphism via a net positive snow grain-size feedback.

Determination of metallic surface areas of platinum - rhenium catalysts

1981 ◽  
Vol 1 (1-2) ◽  
pp. 71-80 ◽  
Author(s):  
Jacques Barbier ◽  
Henri Charcosset ◽  
Gladys de Periera ◽  
Jacques Riviere
Keyword(s):  
Metallic Surface ◽  
Surface Areas
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