Double-Chamber Flow Cell for in situ Infrared Spectroscopy Studies of Chemical Reactions in Ziegler-Natta Catalyst Systems

A complete experimental setup for in situ infrared transmission spectroscopy studies of solid/liquid reactions in Ziegler-Natta catalysts has been developed. The main part of the apparatus, the flow cell, facilitates separate recording of the liquid-phase spectrum and the superimposed solid/liquid spectrum, and thus allows solid and dissolved species during reactions to be distinguished. Addition of solutes and exchange of solution during the experiments are made possible, thus allowing subsequent reactions to be studied. The setup is suited also for liquid reactions, and, in principle, for other chemical systems as well. The construction of the flow cell and the operation conditions are based on pressure-drop calculations of the flow in the apparatus. Two experimental studies are included to demonstrate the use and to document the performance of the setup: (1) the reaction of MgCl2 with dissolved ethyl benzoate and AlEt3 in succession, and (2) the interaction of a MgCl2/ethyI benzoate support during TiCl4 treatment. In the latter, a hitherto unknown TiCl4/EB complex is discovered in the TiCl4 solution.

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IN SITU AND PILOT ORGAN PERFUSION TECHNIQUES FOR THE STUDY OF METABOLIC DYNAMICS

Acta Endocrinologica ◽

10.1530/acta.0.069s009b ◽

1972 ◽

Vol 68 (2_Supplb) ◽

pp. S9-S25 ◽

Cited By ~ 3

Author(s):

John Urquhart ◽

Nancy Keller

Keyword(s):

Cardiac Output ◽

Large Fraction ◽

Experimental Studies ◽

Test Substance ◽

Organ Perfusion ◽

Systemic Blood ◽

Experimental Control ◽

Arterial Blood ◽

Vascular Connections

ABSTRACT Two techniques for organ perfusion with blood are described which provide a basis for exploring metabolic or endocrine dynamics. The technique of in situ perfusion with autogenous arterial blood is suitable for glands or small organs which receive a small fraction of the animal's cardiac output; thus, test stimulatory or inhibitory substances can be added to the perfusing blood and undergo sufficient dilution in systemic blood after passage through the perfused organ so that recirculation does not compromise experimental control over test substance concentration in the perfusate. Experimental studies with the in situ perfused adrenal are described. The second technique, termed the pilot organ method, is suitable for organs which receive a large fraction of the cardiac output, such as the liver. Vascular connections are made between the circulation of an intact, anaesthetized large (> 30 kg) dog and the liver of a small (< 3 kg) dog. The small dog's liver (pilot liver) is excised and floated in a bath of canine ascites, and its venous effluent is continuously returned to the large dog. Test substances are infused into either the hepatic artery or portal vein of the pilot liver, but the small size of the pilot liver and its blood flow in relation to the large dog minimize recirculation effects. A number of functional parameters of the pilot liver are described.

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The role of (bio)surfactant sorption in promoting the bioavailability of nutrients localized at the solid-water interface

Water Science & Technology ◽

10.2166/wst.1999.0336 ◽

1999 ◽

Vol 39 (7) ◽

pp. 91-98 ◽

Cited By ~ 3

Author(s):

Ryan N. Jordan ◽

Eric P. Nichols ◽

Alfred B. Cunningham

Keyword(s):

Mass Transfer ◽

Cell Membrane ◽

Substrate Concentration ◽

Water Interface ◽

Industrial Systems ◽

Solid Liquid Interface ◽

Solid Liquid ◽

Surfactant Sorption

Bioavailability is herein defined as the accessibility of a substrate by a microorganism. Further, bioavailability is governed by (1) the substrate concentration that the cell membrane “sees,” (i.e., the “directly bioavailable” pool) as well as (2) the rate of mass transfer from potentially bioavailable (e.g., nonaqueous) phases to the directly bioavailable (e.g., aqueous) phase. Mechanisms by which sorbed (bio)surfactants influence these two processes are discussed. We propose the hypothesis that the sorption of (bio)surfactants at the solid-liquid interface is partially responsible for the increased bioavailability of surface-bound nutrients, and offer this as a basis for suggesting the development of engineered in-situ bioremediation technologies that take advantage of low (bio)surfactant concentrations. In addition, other industrial systems where bioavailability phenomena should be considered are addressed.

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