Recorded magnetization distributions in thin film disk media

©1998 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.The magnetization distributions in recorded transitions in thin film disk media are shown to consist of simple longitudinal magnetization transitions along with flux closure patterns. Together they give rise to the familiar sawtooth patterns but also indicate why arctangent and other approximations used in record theory have proved so successful even when sawteeth are known to be present

Experimental study of mercury removal from exhaust gases

An initial study has been made of the use of synthetic zeolites for mercury capture from exhaust gases. Synthetic zeolites (Na-X and Na-P1), and for comparison a natural zeolite (clinoptilolite) and activated carbon with bromine (AC/Br) were tested for mercury uptake from a gaseous stream. The materials were subjected to mercury adsorption tests and their thermal stability was evaluated. The untreated synthetic zeolites had negligible mercury uptake, but after impregnation with silver, the adsorption of mercury was markedly improved. The synthetic zeolite Na-X impregnated with silver adsorbed significantly more mercury before breakthrough than the activated carbon impregnated with bromine, indicating the potential of zeolite derived from coal fly ash as a new sorbent for capture of mercury from flue gases

Fly ash-derived MCM-41 as a low-cost silica support for polyethyleneimine in post-combustion CO2 capture

The mesoporous silicate molecular sieve, MCM-41, has been synthesized from pulverized coal fly ash (PFA), where the silicate filtrate used is a by-product from hydrothermal zeolite production. Rice husk ash was also used for comparison but fusion with sodium hydroxide was used to prepare the silicate filtrate, along similar lines to earlier reports of using PFA as a precursor for MCM-41 synthesis. The MCM-41 samples are chemically and mineralogically similar to a commercially available sample, but with higher pore volumes dominated by mesopores (0.92–1.13 cf. 0.88 cm3 g−1). After polyethyleneimine (PEI) impregnation for CO2 capture, the ash derived MCM-41 samples displayed higher uptakes than the commercial sample with the maximum achievable PEI loading of 60 Wt.% PEI (dry basis) before particle agglomeration occurs, approximately 13 compared to 11 Wt.%, respectively, the latter being comparable to earlier reports in the literature. The PFA sample that displays the fastest kinetics to achieve 90% of the equilibrium uptake had the largest mesopore volume of 1.13 cm3 g−1. Given the PFA-derived MCM-41 uses a waste silicate solution for hydrothermal preparation and no prior preparation is needed, production costs are estimated to be considerable lower where silicate solutions need to be prepared by base treatment, even if ash is used, as for the RHA derived MCM-41 used here

Petrophysical and Mineralogical Research on the Influence of CO2 Injection on Mesozoic Reservoir and Caprocks from the Polish Lowlands Études pétrographique et minéralogique de l’impact de l’injection de CO2 dans les roches réservoirs de la Basse Plaine de Pologne

Special equipment, simulating formation conditions, was designed to study interactions between injected CO2, rocks and brines. The investigations were carried out on samples collected from reservoir and caprocks of the Pagórki (Cretaceous deposits) and Brześć Kujawski (Jurassic deposits) boreholes. Mineralogical and petrographic investigations were carried out on the samples before and after the experiment to determine changes occurring as a result of the processes. The investigations proved that these rocks show good quality reservoir and sealing properties. The experiment did not significantly worsen the reservoir properties of the rocks. Afin de mener des recherches sur l’impact CO2 – roche – saumures, nous avons développé un modèle de simulation des conditions de gisement, pour lesquelles l’injection de dioxyde de carbone est envisagée. Des analyses ont été effectuées sur des échantillons de carotte de roche provenant des réservoirs et de la couverture, prélevés dans les forages de Pagórki (formations du Crétacé) et de Brześć Kujawski (formations du Jurassique). Ces échantillons ont été soumis, avant et après les expériences, à des analyses pétrographiques et minéralogiques classiques, afin de déterminer les variations induites par les expériences. Les études menées ont montré que les réservoirs possèdent de bonnes propriétés de stockage de CO2, et les roches de couverture de bonnes propriétés d’étanchéité. L’expérimentation réalisée ne montre pas d’impact notable du gaz injecté sur les propriétés des roches réservoir analysées