Engineering Commons^™

Use Of A Calculator Chip For Realtime Data Processing, Jeffrey O. Cohen, Hal E. Mcloud

Journal of the Arkansas Academy of Science

No abstract provided.

Use Of Extreme Value Theory In Estimating Flood Peaks From Mixed Populations, Ronand V. Canfield, D. R. Olsen, R. H. Hawkins, T. L. Chen

Reports

The flood magnitude for a given frequency or return period is estimated by fitting a probability distribution to the historical annual flood series. The log-Pearson type III distribution has been selected by the Water Resources Council for general use by the federal government, but practitioners should examine an annual flood series and use alternative distributions where they will produce better estimates. Empirical goodness of fit is one criterion for choosing a distribution, but the reasonableness of the assumptions theoretically associated with the form of the distribution should also be considered. In theory, extreme-value distributions are particularly applicable to flow series …

Influence Of Unsaturated Hydraulic Properties On Infiltration From Circular Surface Areas, Abdolhossien Nassehzadeh-Tabrizi, Roland W. Jeppson

Reports

The effects and interactive effects on infiltration of parameters in the Brooks-Corey equation for defining the hydraulic properties of unsaturated soils are investigated by analyzing the results of numerical solutions of the unsaturated flow characteristics resulting from water applied on a circular surface area. The soil parameters are allowed to vary continuously as a function of depth. The parameters that have been allowed to vary separately and in pairs are: (1) The pore size distribution exponent, (2) Pb- The bubbling pressure, (3) Sr- The residual saturation, (4) n- The soil porosity and (5) Ko- The saturated hydraulic conductivity. The conclusions …

Properties Of High Alumina Refractories After Exposure To Steam/H₂ Atmospheres, David W. Lang

Masters Theses

"Selected properties of a dense fired alumina, a phosphate-bonded ramming mix, and a calcium aluminate cement-bonded castable were evaluated after exposure at 260°C and 538°C to steam/H₂ atmospheres (2.58, 5.17, and 6.89) MPa. Chemical reactions in the refractories were determined by x-ray diffraction, DTA/TGA, and changes in physical properties. The modulus of rupture (MOR) of the dense alumina decreased with increasing steam pressure and degree of saturation. The calcium aluminate cement phases in the castable were most reactive in 260°C steam and formed several hydrated phases which generally resulted in a higher MOR. The MOR of the ramming mix …

A Study Of Mechanical Degradation Of A Coarse Aggregate Subject To Repeated Loading, Mark Alan Roenfeldt

Masters Theses

"This investigation concerns itself with the problem of mechanical degradation of a coarse aggregate and specifically as it is used as railroad ballast. Laboratory tests were used to study the aggregate with respect to its plastic deformation characteristics, the amount of degradation, changes in gradation, and the rate of change of degradation as a function of the number of load cycles.

The repeated load triaxial tests were used to study how degradation occurs with respect to aggregate gradation, relative density, and the number of load applications. The Los Angeles abrasion test was also used to determine the degradation of the …

Analysis Of Hardened Concrete For Admixture Content, William Lee Dolch

JTRP Technical Reports

No abstract provided.

Use Of Synthetic Demand Modeling Techniques In Transportation Planning For Small Urban Areas In Indiana, Kumares C. Sinha, Hani S. Mahmassani, James Robert Mekemson, Edward Wilson Hanscom

JTRP Technical Reports

No abstract provided.

Traffic Speed Report No. 112 : Interim Report, Richard Philip Guenthner, George K. Stafford

JTRP Technical Reports

No abstract provided.

Traffic Speed Report No. 113 : Interim Report, Richard Philip Guenthner, George K. Stafford

JTRP Technical Reports

No abstract provided.

The Prediction Of The Freeze/Thaw Durability Of Coarse Aggregates In Concrete By Mercury Intrusion Porosimetry : Interim Report, Meredith Nickels Lindgren

JTRP Technical Reports

No abstract provided.

Evaluation Of Several Maintenance Methods For Continuously Reinforced Concrete Pavements, Eldon J. Yoder

JTRP Technical Reports

No abstract provided.

An Investigation Of Recycling Bituminous Pavements, Volume 1 : Interim Report, James L. Mckinney

JTRP Technical Reports

No abstract provided.

Interframe Television Coding Using Gain And Displacement Compensation, J. A. Stuller, A. N. Netravali, J. D. Robbins

Electrical and Computer Engineering Faculty Research & Creative Works

This Paper Presents Algorithms for Predicting Luminance Changes in Successive Television Frames. the Changes Can Result When Objects in a TV Scene Move or When Illumination Varies. by a Gradient Search Technique, Which Seeks to Minimize a Functional of the Interframe Prediction Error, We Estimate Two Parameters Associated with These Luminance Changes—displacement and Gain. using the Estimates of These Parameters, We Also Develop, for Interframe Coding, Adaptive Predictors and a Segmentor to Determine Which Pels Need to Be Transmitted. We Describe Several Coder Variations and Compare Them by Computer Simulations using Three Substantially Different Scene Sequences. for These Sequences, Gain …

County Road Management - Guidelines For Boards Of County Commissioners, Jean E. Hittle

Indiana Local Technical Assistance Program (LTAP) Publications

The purpose of these guidelines is to provide new County Commissioners in Indiana with a basic orientation of their duties and responsibilities in the management of county road systems. It is also a convenient reference to review.

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 …

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.

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 …

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, …

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.

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 …

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 …

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 …

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.

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 …

Petrology Of North Mississippi Bauxite : A Case For Depositional Bauxite And Kaolin, Charles Nelson Thompson

Electronic Theses and Dissertations

In the past 55 years, there has been considerable debate over the stratigraphic position, genesis, and economic value of North Mississippi bauxite. The aluminum rich deposits are unlike most deposits found around the world. The deposits are associated with 200-300 foot thick marine to nonmarine clays overlain by feldspar poor, fluvial-deltaic sediments. The possible source areas are composed of limestone, marls, sand, and muds ranging in age from Late Cretaceous to Late Paleocene. These factors prohibit the direct application of previous theories derived from studies outside Mississippi. The deposits, therefore, cannot be considered a textbook example of bauxite formation.

To …

The Effects Of Added Softening Agents Upon The Behavior Of Cold Recycled Asphalt Mixtures : Interim Report, Akio Iida

JTRP Technical Reports

No abstract provided.

The Fabric Of A Medium Plastic Clay Compacted In The Laboratory And In The Field : Interim Report, Dean Matthews White

JTRP Technical Reports

No abstract provided.

Additives To Control Slaking In Compacted Shales : Interim Report, Mariappa Surendra

JTRP Technical Reports

No abstract provided.

Irish H & V News

Building Services Engineering

No abstract provided.

Electronic Properties Of Metal Chloride Intercalants Of Graphite*, **, John A. Woollam, M. B. Dowell, A. Yavrouian, A. G. Lozier, G. Matulka

Department of Electrical and Computer Engineering: Faculty Publications

The Shubnikov-deHaas (SdH) effect has been used to study the electronic properties of graphite intercalated with PdC1₂ (stage 3), FeC1₃ (stages 2, 4, 6, and 11), CuC1₂ (stage 1), and WC1₆ (stage 5). For the palladium chloride, ferric chloride, and copper chloride intercalants the SdH spectra are similar: these show frequencies of approximately, 27, 80, 380, and 550 Tesla for fields parallel to the c-axis. The effective masses have been measured for each of these carriers, and are of the order of 0.1 m₀, where m₀ is the free electron mass. These carriers …