Drainage Port Research Articles

A lysimeter system for monitoring soil solution chemistry

In northern temperate and boreal zones, long-term sampling of the soil solution using lysimeter systems requires (i) a lysimeter that can be installed with a minimum of soil disturbance, (ii) a lysimeter that is small enough to install in stony soil but large enough to representatively sample the soil solution, (iii) a system with a constant tension that integrates soil solution sample collection over time, and (iv) a system that will not break under freezing conditions. A lysimeter system that meets these requirements was designed, and consists of a lysimeter (a fritted glass plate mounted on a glass casing) connected in series to a sample bottle and a tension-generating unit. The glass casing of the lysimeter has two ports: a drainage port for continuous flow of soil solution to the sample bottle, and an access port that can be used (i) for air entry to facilitate complete sample retrieval, (ii) for cleaning, (iii) for re-wetting the fritted glass plate, or (iv) for winterizing the lysimeter with alcohol. A 1-m hanging water column was used to supply a constant tension of approximately 10 kPa. A potential 93% efficiency rate of sample collection can be achieved, and the systems are capable of sampling soil solution beneath organic horizons, as well as in the rooting zone of mineral horizons. The system is presently being used to evaluate the effects of different harvesting and silvicultural treatments on nutrient cycling processes in the soil. Almost 700 of these lysimeter systems are in use in the Atlantic provinces of Canada. The lysimeters have been functioning satisfactorily for over 10 yr and are suitable for long-term monitoring of the soil solution. Key words: Lysimeter design, soil monitoring methodology, nutrient cycling

Controlled Continuous Spinal Drainage Using a Flow-Regulated Pump

Controlled Continuous Spinal Drainage Using a Flow-Regulated Pump

Monitoring of Ventilation on and off Cardiopulmonary Bypass

Monitoring of Ventilation on and off Cardiopulmonary Bypass

Pseudoepidemic of Urinary Tract Infections due to Trichosporon beigelii

AbstractDuring the period April, 1985 to March, 1986, Trichosporon beigelii was isolated from the urine of 15 intensive care unit patients. All of these patients had Foley catheters in place at the time of T beigelii isolation. None of them had urinary tract infections on admission, and it was initially felt that this organism was a source of infection in these critically ill individuals. Subsequent investigation revealed this to be a pseudoepidemic secondary to contamination of the urinary catheter drainage system. Urine obtained by gravity drainage from the outlet port of urimeters yielded growth of T beigelii, whereas urines obtained concurrently from the proximal tubing sampling port were negative. T beigelii was isolated from the drainage port as well as from various items used in the collection and sampling of urine specimens. It is felt that these items were the source of perpetuation of this pseudoepidemic due to the repeated contamination and colonization of the distal portion of the urine catheter collection system. In-services to nursing and housekeeping personnel in the proper collection of urine specimens and cleaning of potentially contaminated items, the replacement of metal urine graduates with disposable plastic ones and increased monitoring of personnel's activities stopped the outbreak abruptly.

Pseudoepidemic of urinary tract infections due to Trichosporon beigelii.

During the period April, 1985 to March, 1986, Trichosporon beigelii was isolated from the urine of 15 intensive care unit patients. All of these patients had Foley catheters in place at the time of T beigelii isolation. None of them had urinary tract infections on admission, and it was initially felt that this organism was a source of infection in these critically ill individuals. Subsequent investigation revealed this to be a pseudoepidemic secondary to contamination of the urinary catheter drainage system. Urine obtained by gravity drainage from the outlet port of urimeters yielded growth of T beigelii, whereas urines obtained concurrently from the proximal tubing sampling port were negative. T beigelii was isolated from the drainage port as well as from various items used in the collection and sampling of urine specimens. It is felt that these items were the source of perpetuation of this pseudoepidemic due to the repeated contamination and colonization of the distal portion of the urine catheter collection system. In-services to nursing and housekeeping personnel in the proper collection of urine specimens and cleaning of potentially contaminated items, the replacement of metal urine graduates with disposable plastic ones and increased monitoring of personnel's activities stopped the outbreak abruptly.

Stomach Rupture by Infusion Pump and Foley Catheter

A nine-month-old girl who had successfully undergone surgery for esophageal atresia sustained a rupture of the stomach when an infusion pump was inadvertently connected to the balloon port of a Foley catheter being used as a gastrostomy tube. A strong similarity in appearance and feel of the balloon port and the drainage port of the catheter was created when a clear plastic adapter was inserted in the drainage port for connection of the pump tubing. Other factors contributing to the accident were poor lighting at the time of the connection, failure of the infusion pump occlusion alarm to activate at pressures low enough to prevent injury, and the reduced size of the child's stomach following surgery.

The crossflow piston bed

The moving piston bed is a device for producing washed crystals from a slurry feed. Necessary for predicting the quality of a conceptual bed geometry is an evaluation method which accurately reveals the flow patterns in the dynamic system. The electrical analog method serves as a versatile guide to an evolutionary development of improved designs. All beds with a submerged drainage port have, for a given geometry, a unique relationship between loss of displacement fluid and rate of bed advance. The hydraulic diagram is unchanged, by the magnitude of applied forces. For rating productive capacity the use of gravity forces as a reference standard is recommended. A crossflow design is developed that predicts a productive rate over three times that achievable by downflow washing.