We compare computational simulations of the flow of air through a packed column containing spherical particles with experimental and theoretical results for equivalent beds. The column contained 160 spherical particles at an aspect ratio N = 7.14, and the experiments and simulations were carried out at particle Reynolds numbers of (Redp = 700 − 5000). Experimental measurements were taken of the...

A novel method was developed for the preparation of highly efficient anion- and cation-exchange microHPLC columns using an on-column polymerization of methacrylates having amine or sulfonic acid functional groups onto monolithic silica capillary columns modified with 3-methacryloxypropyltriethoxysilane as the anchor groups. The chromatographic evaluation of the columns using nucleic acids, nucl...

The hetght of an ovemll transfer unat has been evaluated m a gas-solid packed column at tnckle flow by measunng column performance during steady state adsorption expertments. Results have been anterpreted wtth an extmctton model mass transfer and axial dispersaon ua both phases Usmg Bodenstem numbers for the gas and solid phases from a previous investagation the hetght of a true transfer untt h...

The HPLC/MS system, in which a monolithic silica capillary column is directly connected to an electronspray-ionization mass spectrometer, showed superior performance at high mobile phase linear velocity. A two-dimensional (2D) HPLC/MS system was established, using an ion-exchange particle-packed capillary column at the first dimension and a monolithic silica capillary column at the second dimen...

Porous sol-gel frits are fabricated in a capillary column by filling it with a solution of 3-(trimethoxysilyl)propyl methacrylate, hydrochloric acid, water, toluene (porogen), and a photoinitiator (Irgacure 1800) and exposing it to UV light at 365 nm for 5 min. The separation column (30 cm x 75 microm I.D.) contains between the inlet and outlet frits a 15-cm packed segment filled with 5-microm ...

Rigid chromatography resins, such as controlled pore glass based adsorbents, offer the advantage of high permeability and a linear pressure-flow relationship irrespective of column diameter which improves process time and maximizes productivity. However, the rigidity and irregularly shaped nature of these resins often present challenges in achieving consistent and uniform packed beds as formati...

The crystal structure of the title compound, C(8)H(5)Br(3)ClNO, shows both intra-molecular N-H⋯Br and inter-molecular N-H⋯O hydrogen bonding. In the crystal, the mol-ecules are packed into column-like chains in the c-axis direction via the N-H⋯O hydrogen bonds.

A gas-chromatographic analysis of vinylidene chloride (1,1-dichloroethylene) is presented. Vinylidene chloride was sampled by adsorbing on activated carbon. It was desorbed with carbon disulfide. The desorption efficiency was 97.2 +/- 1.05 (mean +/- standard error). The analytical column was packed with 10% Apiezon L on acid-washed Chromosorb-P. The analysis was conducted on a gas chromatograph...

The example of column chromatography (Figure 1) demonstrates the typical features found in this analytical technique. The diagram shows an experiment where a two-component mixture is subjected to column chromatography. The column is packed with a solid material called the stationary phase. A liquid solvent or eluting solution is poured into the column and completely wets the solid packing mater...

Column-oriented database systems (column-stores) have attracted a lot of attention in the past few years. Column-stores, in a nutshell, store each database table column separately, with attribute values belonging to the same column stored contiguously, compressed, and densely packed, as opposed to traditional database systems that store entire records (rows) one after the other. Reading a subse...