Tomography of Carbon Black for Surface Area Measurement

Currently, the morphology of carbon black is described by distributive morphological properties that are measured using two dimensional TEM projections of the carbon black aggregates. The area, perimeter and several Feret diameters of 2000 such aggregate projections are measured with an automated system and used to calculate a number of parameters including the mean primary particle diameter and the surface area of the carbon black in m2/g. Several assumptions must be made in order to carry out these calculations, the first being that the aggregates are either isotropic or randomly oriented. True random orientation is impossible due to the flat surface on which the carbon black is deposited. For relatively compact spherical, ellipsoidal and linear aggregates this assumption works fairly well. However, the more highly structured a carbon black aggregate is, the worse this assumption becomes. Studies of these types of aggregates have shown that the two dimensional projected area and perimeter can decrease up to 25% as the viewing angle is increased from 0° to 45°. The use of electron tomography to determine surface area will eliminate this problem. in addition, the use of tomographically reconstructed carbon black aggregates for the determination of surface area is a more direct measurement technique, although limitations to its accuracy do exist.

Interval Method for Interrogation of Implicit Solid Models

Computer-aided design/manufacturing (CAD/CAM) systems intended to support automated design and manufacturing applications such as shape generation and solid free-form fabrication (SFF) must provide not only methods for creating and editing models of objects to be manufactured, but also methods for interrogating the models. Interrogation refers to any process that derives information from the model. Typical interrogation tasks include determine surface area, volume or inertial properties, computing surface points and normals for rendering, and computing slice descriptions for SFF. While currently available commercial modeling systems generally employ a boundary representation (B-rep) implementation of solid modeling, research efforts have considered implicit modeling schemes as a potential source of improved robustness. Implicit implementations are available for a broad range of modeling operations, but interrogation operations have been widely considered too costly for many applications. This paper describes a method based on interval analysis for interrogating implicit solid models that aims at achieving both robustness and efficiency.

Pembuatan Katalis Pd-Ce/γ –Al2O3 dan Uji Aktivitas terhadap Oksidasi Metana

Effects of Ce addition on Pt/γ - Al2O3 catalysts preparation and their catalytic activity on oxidation of methane have been investigated. In this study, the catalysts were prepared by impregnating chloride salt solution of palladium and sulphate salt of cerium on γ-AI2O3 support. Characterization of catalysts was conducted by gas sorption method to determine surface area, pore radius and pore volume. The test of catalytic activity on oxidation of methane was carried out in a flow reactor system at a temperature range from 350°C to 600°C. Products of reaction were analysed by non-dispersive IR spectroscopy. It was observed that the surface area, pore radius and pore volume decrease with the addition of cerium. The results of oxidation process showed that Pd-Ce/γ-Al2O3 catalyst can be used for oxidation of methane up to 90.62% conversion

HALIFAX '83 SEA TRIAL OF OIL SPILL DISPERSANT CONCENTRATES

ABSTRACT In September 1983, the Canadian Offshore Aerial Applications Task Force conducted a 3-day oil spill dispersant field trial using the commercial products Corexit 9527, Corexit 9550, and BPMA 70. A different dispersant concentrate was applied each day to one of two 15 barrel spills of 13 percent weathered Alberta crude oil using a Bell 212 transported Rotortech TC-3 spraying bucket. Both treated and control slicks were surveyed using remote sensing aircraft to determine surface area, spreading rates, and major differences in slick thickness. A water sampling program was undertaken to determine the extent of dispersant effectiveness. Sea conditions during the first two days' work (9527 then 9550) were comparable with a moderate increase in mixing energy on the third day (BPMA 700). Against these conditions, and with corresponding dispersant to oil ratios of 1:27, 1:8, and 1:9, the percentage of weathered oil dispersed into the water column was calculated to be 3.75, 20.5, and 41 respectively.