English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

Two methods for preparing waste-oil samples to permit measurement of their metals content were evaluated. For this evaluation, metals-in-oil standard reference materials were prepared by each method and the resulting solutions were analyzed for 20 metals, including those (As, Ba, Cd, Cr, Pb, Hg, Se, and Ag) regulated as hazardous under the Resource Conservation and Recovery Act. One preparation method involved combustion of the waste oil under oxygen at 25 atm pressure, as described in the American Society for Testing and Materials test method E926-88. As we applied it, this method gave recoveries well under 90% for most of the metals that we examined and, hence, proved unsatisfactory for routine application to waste-oil analysis. With the other method, nitric acid decomposition in a sealed vessel heated with microwave energy (analogous to US Environmental Protection Agency Method 3051), recoveries of all 20 metal contaminants were within 90 to 110% of the certified values. This microwave digestion procedure was also more efficient since it allowed six samples to be prepared together, whereas the oxygen combustion approach allowed processing of only one sample at a time

Preparation of waste oil for analysis to determine hazardous metals