Biomedical subjects

B D Etter

Publications and source records attributed to B D Etter.

3 recordsLinked to original sources

PubMed1996

A system for studying the gas exchange of whole plants at subambient total gas pressures.

A whole-plant gas exchange system that has been designed and constructed to study the feasibility of growing plants at subambient total gas pressures is described. This system will allow for the study of whole-plant gas exchange over the entire life cycle of a plant. The system also will allow for the regulation of atmospheric composition by providing control over the amount of nitrogen, oxygen, and carbon dioxide in a chamber atmosphere. The chamber's environmental performance is discussed in relation to selected design requirements. This system is a major technological advance over other systems used to study low-pressure effects on plant growth.

Air Conditioning↗

PubMed1993

Evaluation of a multiple disk centrifugal pump as an artificial ventricle.

A multiple-disk centrifugal pump based on the Tesla Turbine design has been modified for potential use as an artificial ventricle or ventricular assist device. The pump consists of a series of interconnected parallel disks placed within a spiral volute housing. This pump normally operates as a continuous flow device; however, a controller circuit has been developed to also allow for pulsatile operation. Frequency, systolic duration, systolic rise time, and diastolic decay time can be independently controlled to produce a wide range of pulsatile pressures and flows. This pumping system was tested in vitro on a mock circulatory system using a blood analogue. Inlet and outlet pressures, outlet flow, and motor rotations per minute were continually monitored over a wide range of physiologic operating conditions. The disk pump output was compared with that of other artificial ventricles and produced favorable results. Direct experimental comparisons were made with a Harvard Apparatus pulsatile piston pump. Unlike the Harvard pump, the disk pump does not use valves. Rather, a slight forward rotation of the disks is used to offset the adverse diastolic pressure gradient, which avoids backflow through the device.

Equipment Design↗

PubMed1990

A multiple disk centrifugal pump as a blood flow device.

A multiple disk, shear force, valveless centrifugal pump was studied to determine its suitability as a blood flow device. A pulsatile version of the Tesla viscous flow turbine was designed by modifying the original steady flow pump concept to produce physiological pressures and flows with the aid of controlling circuitry. Pressures and flows from this pump were compared to a Harvard Apparatus pulsatile piston pump. Both pumps were connected to an artificial circulatory system. Frequency and systolic duration were varied over a range of physiological conditions for both pumps. The results indicated that the Tesla pump, operating in a pulsatile mode, is capable of producing physiologic pressures and flows similar to the Harvard pump and other pulsatile blood pumps.

Assisted Circulation↗