18 research outputs found
Content Schema Evolution in the CoreMedia® Content Application Platform CAP
Based on experience gathered with several releases of the CoreMedia Content Application Platform (CAP), we argue that a modern, generalized Content Management System should, as database systems do, support explicit content schemata. To control the inevitable evolution of the content schema, the schema should be subject to configuration management together with the actual content. We propose a two-layered approach to content schema evolution consisting of -- a system level responsible for bookkeeping and integrity issue detection, and -- a semi-automatic application level responsible for resolving schemarelated issues
On-Line Mass Spectrometric Methods for the Determination of the Primary Products of Fast Pyrolysis of Carbohydrates and for Their Gas-Phase Manipulation
Mass
spectrometric methodology was developed for the determination
and manipulation of the primary products of fast pyrolysis of carbohydrates.
To determine the true primary pyrolysis products, a very fast heating
pyroprobe was coupled to a linear quadrupole ion trap mass spectrometer
through a custom-built adaptor. A home-built flow tube that simulates
pyrolysis reactor conditions was used to examine the secondary reactions
of the primary products. Depending on the experiment, the pyrolysis
products were either evaporated and quenched or allowed to react for
a period of time. The quenched products were ionized in an atmospheric
pressure chemical ionization (APCI) source infused with one of two
ionization reagents, chloroform or ammonium hydroxide, to aid in ionization.
During APCI in negative ion mode, chloroform produces chloride anions
that are known to readily add to carbohydrates with little bias and
little to no fragmentation. On the other hand, in positive ion mode
APCI, ammonium hydroxide forms ammonium adducts with carbohydrates
with little to no fragmentation. The latter method ionizes compounds
that are not readily ionized upon negative ion mode APCI, such as
furan derivatives. Six model compounds were studied to verify the
ability of the ionization methods to ionize known pyrolysis products:
glycolaldehyde, hydroxyacetone, furfural, 5-hydroxymethylfurfural,
levoglucosan, and cellobiosan. The method was then used to examine
fast pyrolysis of cellobiose. The primary fast pyrolysis products
were determined to consist of only a handful of compounds that quickly
polymerize to form anhydro-oligosaccharides when allowed to react
at high temperatures for an extended period of time