Engineering Commons^™

Metric Units Of Measure- Part I Length, Area And Volume, Elbert C. Dickey, Allen R. Rider, Gerald R. Bodman

Biological Systems Engineering: Papers and Publications

The metric system was developed by government and scientific groups in 1790 to replace a host of diverse measuring systems used throughout France. By the early 1900's it had been adopted by most European and Latin American nations. By 1970 over 90 percent of the world, including all major industrial nations except the United States, had either adopted the metric system or had undertaken programs to implement it.

Use of the decimal-based metric system was made legal in the United States by Congress in 1866. Although some scientists and educators readily adopted the metric system, little acceptance was made by …

Metric Units Of Measure - Part Ii Fluid Volume, Mass, Temperature, Pressure, Power And Energy, Elbert C. Dickey, Allen R. Rider, Gerald Bodman

Biological Systems Engineering: Papers and Publications

The metric and U.S. customary systems of measure differ in terminology for fluid volume, mass, temperature, pressure, power and energy. The relationships between the metric and U.S. customary system for these units are described and illustrated graphically in the following text.

Fluid Volume- Fluid volumes are usually measured in milliliters or liters. Small quantities of liquid products are expressed as milliliters or as cubic centimeters. Gasoline, milk and other similar sized volumes are measured in liters.

Mass - Mass is the amount of matter in an object and is normally referred to as weight. The common metric units of …

Lecture Draft On Sensory Recall Device - 1980, Wendy J. Gordon

Scholarship Chronologically

Perception is a bodily function. The brain “sees” according to the orders which the optic nerve relays from its position at the back of the eye. Similarly, it is the brain which also "hears." As we know from our dreaming and our remembering, neither eye nor ear is indispensable to having the sensations of seeing and hearing.

Influence Of Adrenergic Drugs Upon Vital Organ Perfusion During Cpr, H R. Holmes, Charles F. Babbs, W D. Voorhees, W A. Tacker, B De Garavilla

Weldon School of Biomedical Engineering Faculty Publications

To determine whether adrenergic drugs administered during cardiopulmonary resuscitation (CPR) alter the distribution of artificial card:l.ac output, we measu"red regional blood flow and cardiac output using radioactive microspheres in 12 dogs. Ventricular fibrillation was induced electrically and CPR was immediately begun with a mechanical chest compressor and ventilator (Thurn per ( R) ) at 60 compressions/min, with a ventilation:compression ratio of 1:5, a compression duration of 0.5 sec, and a ventilation pressure of 20 em H 2 o. Compression force was sufficient to develop 40-50 mmHg peak intraesophageal pressure. After 30 sec of CPR, either 0.9% saline vehicle or 50 …

Regional Blood Flow During Cardiopulmonary Resuscitation In Dogs, W D. Voorhees, Charles F. Babbs, W A. Tacker

Weldon School of Biomedical Engineering Faculty Publications

To determine differences in regional blood flow during cardiopulmonary resuscitation (CPR) versus normal cardiac function, we measured regional blood flow to sev~ral organs in 19 pentobarbital-anesthetized dogs (6-12 kg). Regional blood flow was measured during sinus rhythm in 5 dogs and during electrically induced ventricular fibrillation with CPR in the other 14 dogs. Regional blood flow and cardiac output were measured using radioactively labelled polystyrene microspheres of 15 ±3P diameter, injected into the left ventricle. Adequacy of microsphere mixing at low cardiac outputs was verified by comparing flow rates to paired organs. Cardiac output was 175 ml/kg/min during sinus rhythm …

A New Technique For Repeated Measurement Of Cardiac Output During Cardiopulmonary Resuscitation, L A. Geddes, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

We have developed a method for measurement of cardiac output during CPR with ventricular fibrillation. The method avoids the problems encountered when conventional techniques are used under the conditions of very low cardiac output. The method consists of injecting 5% saline as the indicator into the left ventricle and detecting its appearance in the descending aorta by withdrawing blood through an electrically calibrated conductivity cell. The adequacy of indicator mixing has been verified by obtaining dilutions curves simultaneously from the brachial and femoral arteries. Cardiac output can be determined even when output is as low as 7 ml/min/kg during CPR …

Therapeutic Indices For Transchest Defibrillator Shocks: Effective, Damaging, And Lethal Electrical Doses, Charles F. Babbs, Willis A. Tacker, John F. Vanvleet, Joe D. Bourland, Leslie A. Geddes

Weldon School of Biomedical Engineering Faculty Publications

Although prospective studies of defibrillator shock overdose cannot be performed in man, the therapeutic indices of various defibrillating current waveforms can be measured in animals. We determined the ratios TD50/ED50 and LD50/ ED50 (where TD50 = median "toxic" or damageinducing dose, ED50 = median effective or defibrillating dose, and LD50 = median lethal dose) as measures of the therapeutic index for damped sine wave defibrillator shocks in dogs. Death of an animal and/or any degree of cardiac damage found by gross or microscopic examination were defined as harmful effects of shock, analogous to drug toxicity. In terms of peak current, …

New Versus Old Theories Of Blood Flow During Cpr, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Today, the physiology of blood flow during external chest compression appears more complicated than had previously been imagined. New evidence requires that at least two possible mechanisms be considered for generating artificial circulation by external chest compression. The first is the classical mechanism in which the heart propels blood because it is squeezed between the sternum and the spine. The second is a more recently appreciated mechanism in which the entire thorax acts as a pump because of global intrathoracic pressure changes. The first might be called the cardiac pump mechanism and the second might be called the thoracic pump …

Evaluation Of The Operating Internal Resistance And Capacitance Of Intact Trapezoidal Waveform Defibrillators, Charles F. Babbs, Sj Whistler, La Geddes

Weldon School of Biomedical Engineering Faculty Publications

No abstract provided.

Influence Of Interposed Ventilation Pressure Upon Artificial Cardiac Output During Cardiopulmonary Resuscitation In Dogs, Charles F. Babbs, W D. Voorhees, K R. Fitzgerald, H R. Holmes, L A. Geddes

Weldon School of Biomedical Engineering Faculty Publications

This study was conducted to determine the effects of high pressure interposed ventilations during cardiopulmonary resuscitation (CPR). Cardiac output was measured by a modified indicator dilution technique in eight anesthetized, intubated mongrel dogs. Positive pressure ventilations (12/min, 80% O2) were interposed after every five chest compressions (performed at 62/min) by a mechanical chest compressor (Thumper®). On repeated trials in the same animal, ventilation pressures from 10-50 cm of H2O were tested in randomized sequence, while the technique of chest compression was held constant. Arterial blood gases immediately after resuscitation were monitored. Increasing ventilation pressure had surprisingly little effect on cardiac …

Dependence Of Defibrillation Threshold Upon Extracellular/Intracellular K+ Concentrations, Charles F. Babbs, S J. Whistler, G Yim, L A. Geddes

Weldon School of Biomedical Engineering Faculty Publications

The effect of increasing extracellular potassium concentration (K_o) upon electrical ventricular defibrillation threshold was investigated in pentobarbital anesthetized dogs treated with intravenous potassium chloride. Defibrillation threshold fell during potassium intoxication. The percent decrease in defibrillation threshold was linearly related to the logarithm of K_o and to the potassium equilibrium potential, E_K, calculated from measured extracellular and intracellular potassium concentrations of ventricular muscle. In dogs supported by left ventricular bypass in order to maintain the circulation during potassium intoxication, the values of K_o and E_K required for spontaneous, K⁺ induced defibrillation (electrical defibrillation …

An Animal Model For Testing Automatic Defibrillators, J D. Bourland, Charles F. Babbs, W A. Tacker, L A. Geddes

Weldon School of Biomedical Engineering Faculty Publications

A promising therapy for ventricular fibrillation--a life-threatening cardiac arrhythmia--is the implantation of an automatic defibrillator. A critical component of such a device is the system that detects the presence of ventricular fibrillation. Automatic systems for detecting ventricular fibrillation have been tested with arrhythmias produced by electric shocks in normal canine hearts, but have not been tested with spontaneous arrhythmias in hyperirritable hearts. We have developed an animal model to create arrhythmias without electrical stimulation and have used it to test our automatic defibrillator. This model permits evaluation of both reliability to diagnose ventricular fibrillation and reliability to reject other tachyarrhythmias.

Design Of Vegetative Filters For Feedlot Runoff Treatment In Humid Areas, D. H. Vanderholm, Elbert C. Dickey

Biological Systems Engineering: Papers and Publications

The vegetative filter approach uses overland flow or shallow channelized flow to treat feedlot runoff by infiltration, dilution and filtration. Based on extensive monitoring of four field systems in Illinois over a two year period, acceptable performance standards were selected. Design criteria to meet the standards were developed for both the overland flow vegetative filters and the channelized or serpentine terrace filters. A major design criterion for both types of vegetative filters is the time required for applied runoff to flow the length of the filter.

An alternative to using zero-discharge treatment systems to control feedlot runoff is to replace …

Dynamic Intraesophageal Imagining Of The Heart With Ultrasound, N E. Fearnot, Charles F. Babbs, J D. Bourland, L A. Geddes

Weldon School of Biomedical Engineering Faculty Publications

Real-time images of the heart from within the esophagus are produced by a new intraesophageal ultrasonic sector scanner. Sixty images per second are displayed on a gray scale CRT in real-time and recorded on standard videotape for review. By interactive positioning of the esophageal probe, heart ventricles, atria, and valves can be visualized and their dynamics can be studied. The esophageal probe comprises four 5 MHz PZT-5 piezoelements of 6.35 mm diameter, mounted on a shaft that rotates at 900 rpm. The piezoelements are pulsed at a 5 kHz rate and the echoes are processed electronically.

Home Sewage Treatment Systems, Elbert C. Dickey, Robert P. Pharris, Phillip W. Harlan, Gary Hosek

Biological Systems Engineering: Papers and Publications

Homeowners in areas not served by municipal sewage treatment systems face a problem of providing safe and effective wastewater treatment systems for their homes.

There are several methods currently available for proper treatment of home sewage, including septic tank absorption fields, mounds, lagoons, aerobic treatment units and others. These systems and their advantages and disadvantages are discussed in this NebGuide.

Treatment and disposal of domestic sewage is of concern because of the variety of pathogenic organisms contained in sewage. These include bacteria, viruses, and other microorganisms that come from the digestive tract, respiratory tract, and skin of man. Some of …