IIT's 1996 Annual
Undergraduate Research Conference

The regulation of human respiration is not yet fully understood. This project investigated the possible role of the Hering-Breuer deflationary reflex in the modulation of respirato ryrhythm. This reflex can be observed in animals and newborn infants, but is commonly believed to be absent in adults. The hypothesis to be tested was that a rapid deflation ofthe lungs during naturally occurring expiration would evoke an earlier onset of the succeeding breath. Air flow at the mouth was measured with a pneumotachograph, and diaphragmatic EMG activity was recorded using an intraesophageal electrode to determinethe duration of a breath. Deflation of the lungs was achieved by a weak manual compression of the abdomen. Duration of normal breaths was compared with breaths where the lungs were deflated. Data was processed digitally and a nonlinear filtering algorithm was developed to remove ECG artifacts. The evaluation of 5 subjects revealed asignificantly earlier onset of inspiration after a compression. Only one comparable studywas found. There, Guz and his coworkers tried to demonstrate the existence of this reflexin adults by chest compression, but were not successful. Their findings suggest a novel way of eliciting the Hering-Breuer deflationary reflex and give evidence that this reflex maybe present in adults.

In rehabilitation, determining the weight distribution between each foot and the total weight borne on each limb during a step is a very important process The understanding of this process is critical to help stroke and paraparetic patients regain usage of a limb. The purpose of this research is to design a simple, easy to use, and accurate device that can indicate to a clinician if a subject has loaded the affected limb completely or not. Using force sensing resistors (FSR's) as the force sensing instrument, a simple software package to convert analog data to digital data, and a force plate for calibration, the device will first be tested for its accuracy and precision using normal subjects. Then, it will be applied to a rehabilitation setting for measuring affected gait. Currently available force plates, though more accurate than sensors, are costly and cumbersome. Thus, sensor devices are more feasible in a clinical setting. The overall goal of this research is to allow clinicians to properly utilize and extract useful information from the device without any technical supporton hand. This is important in gait rehabilitation in physical therapy.

This project was undertaken in order to fulfill some needs presented in a rehabilitation hospital in Chicago to remind a patient every so often of some exercises to perform. It also conceivably can be used to emit a verbal warning signal when a person gains access to a controlled area, or to give a friendly reminder to the personnel to execute practices required by the nature of their duties. The finished device takes up no more room than a regular small tape recorder.

The heart of the device described in this report is a voice record/playback integrated circuit. The ISDIOOOAP IC allows direct access to any part of the on-chip memory for playing back or recording purposes. Different messages can be stored within a total 20 second recording span. This recording time can be increased by cascading several chips. In order to record or play back a message, the starting point can be reached without involving mechanical parts by digital addressing. There is no explicit way of deleting unwanted messages; new messages simply overwrite old ones. In addition, this device can be activated by signals coming from sensors or digital devices.

This device may offer considerable market appeal. All its components can be acquired over the counter. Its assembly involves light manufacturing. There is no need for programming. Also, it can be actuated via a microprocessor which adds flexibility to customize users'needs.

Conventional design procedure for biological reactors assumes that the degradation of pollutant is either by suspended or attached biomass. Attached biomass includes biomass that collects and forms a thin layer of biofilm on the walls of a biological reactor, while suspended biomass is simply suspended within the liquid medium of the reactor. The degradation rate equation for the suspended biomass or the biofilm is then used to calculate the reactor size required to achieve a prescribed treatment efficiency.. However, all real word reactors (biological) contain both suspended and attached biomasses that degrade simultaneously the pollutant. Yet, which form of biomass is responsible for the degradation of pollutant at a faster rate? The objective of this project is to find out the form of biomass that is most dominant in degrading pollutant at a higher rate. Mathematical models for both suspended and attached biomass was used to perform a sensitivity analysis to evaluate the dominant form of biomass.

The total knee replacement has helped thousands of people to walk again. However, small particulates of the polyethylene are produced as a result of the wear and tear of the knee over time. This degradation causes the patient great pain and may also lead to replacement of the artificial knee. Studies have been conducted by various institutions to understand why the polyethylene decomposes in the body. The durability of the polyethylene depends on the initial physical properties such as particle size, molecular weight, and crystallinity, the processing conditions involved with compression molding, such as temperature, pressure, and the atmosphere of the mold (air versus an inert gas), and finally, the post processing of the polyethylene including the cooling rate, shelf life, sterilization, and oxidation. The effect of oxidation on the tensile strength of the polymer is the subject of this study.

Laser Doppler Anemometry techniques have been developed for the measurements of two phase flow parameters under the coexistence of a liquid-gas flow system. Based on the principle of geometric optics, both forward and backward scattering modes are adopted for the receiving optics. The threshold technique is used for the backward scattering mode to suppress the signals generated by the liquid phase and to make sure that the signal processor can be triggered only by the signals generated by bubbles. When the bubble size is large, the liquid-gas interface will act mainly as a reflecting mirror. This makes the forward receiving optics sitting on the optical axis receive the light scattered by tracer particles only. In addition, it is now possible to measure the liquid phase velocity under the coexistence of two phases. This technique has been applied to a liquid-gas flow system to dynamically measure two phase velocities, particle size, and turbulence intensities of both phases. Turbulence intensities are then compared with that of a single phase liquid in order to study the effect on the liquid due to the presence of bubbles. The experimental results show that this technique is indeed successful for the measurements of two phase flow parameters under the existence of the liquid-gas flow system.

Antifreeze polypeptides (AFP) are proteins that are produced in the blood of many Antarctic fishes, especially the winter flounder, who reside in subzero temperature waters.These cryoprotectants, along with the presence of other polypeptides and solutes have been found to allow the flounder to survive in water temperatures as low as -1.8C. This study is aimed at understanding the mechanics by which the polypeptide is able to inhibit the growth of ice crystals in the blood. The applications of such research include blood storage, cryogenics, and possibly more efficient food storage techniques.

Using molecular simulations, the binding of HPLC-6 (the AFP found in the flounder), was studied. CHARMm v23 and Cerius2 were used to perform a series of docking simulations inwhich energy minimization calculations were used to determine stable configurations atwhich the polypeptide most likely resides. Hydration studies were performed using CHAIN and Quanta 3.3 software packages. In this way, fingerprinting analyses were conducted to calculate the water density around the polypeptide to understand the water interaction with the polypeptide. The effect of ice on the AFP was studied by running separate simulations with varying ice surface and ice lattice coordinates. Five comparison studies were performed: (1) fixed ice, partially fixed ice, and one-free top layer of ice slabs; (2) Basal ice surface vs [2021] ice surface; (3) bent AFP conformation vs. straight conformation; (4) rotation of the AFP along its axis at the values of 0, 90, 180, and 270 degrees; and (5) hydration simulations vs the straight and bent AFP. The hydration study data was also further used in the fingerprinting analysis to study the effect of water on the AFP.

At present, the data collected during the docking simulations are still being analyzed and further simulations are being run. It is also difficult to discuss the findings of the fingerprinting analysis since that portion of the study is not yet completed.

We report the synthesis of per-6-thio-a-cyclodextrin (a-CDT) and the characterization of self-assembled monolayers formed by the sequential self-asembling of 1-dodecanethiol(DDT) followed by a-CDT on polycrystalline gold electrodes. These two-component monolayers are highly catalytic towards the reduction of the 2- & 4- nitroanisoles, and the 2& 4- nitrobenzyl alcohols. In addition, the kinetically irreversible voltammetry of hydroquinone, 2,3-dimethylhydroquinone and catechol (deltaEp > 500 mV) on bare gold in neutral phosphate buffer is contrasted with the quasi-reversible (deltaEp < 50 mV) voltammetry of these hydroquinones on a-CDT/DOT modified gold surfaces. Steric selectivity of these electrodes is evidenced by the significantly larger positive shifts exhibited in the reduction waves of the para isomers of the anisoles and benzyl alcohols at the a-CDT/DOT electrodes.

The term "dehydrogenase" is used to describe the ability of a molecule to remove hydrogen(H2) from another molecule. The most famous molecular example of a dehydrogenase is nicotinamide adenine dinucleotide (NAD) which is responsible for converting ethyl alcohol (after beverage consumption) into acetic acid for eventual excretion. Another example is the colored cofactor, PQQ. Abstraction of hydrogen by PQQ is expected to result in a color change. Recently, we have discovered a more simple molecule, I, which mimics the activity of PQQ. Reaction of I with various amines and hydrazines results in removal of H2 and adramatic color change from red I to fluorescent yellow 11. This poster will discuss the scope of this reaction and provide insight into the chemical mechanism. Potential applications for the detection of rocket fuel leaks and in medicinal chemistry will bepresented.

While interactive tutorials have existed at the grammar and high school levels for some time now, there is still little material on the market at the college level, especially in the area of Physics and Engineering. The aim of this project is to develop interactive tutorials for students in college level courses through the use of Hypercard. Hypercard allows for the easy integration of multimedia into tutorials, which is often a necessity in getting the concepts in advanced material across to students. A base template will be developed so that instructors in any class can create custom tutorials to serve the needs of their students. These tutorials will allow students to view topics on many levels as well as tocross reference between topics. The hope is to develop a self-paced learning experience that will serve students at all academic levels.

Sonoluminescence is the phenomenon of light emission when bubbles trapped in a liquid are excited by sound. To produce this, a spherical 100 ml flask was filled with distilled and filtered water and was then degassed. Two piezoelectric transducers were attached to opposite sides of the flask. When air bubbles are introduced into this water, a small bubble gets trapped in the pressure antipode of the standing wave produced by the spherical sound waves. This bubble has been observed to emit flashes of light at regular intervals. Under delicate laboratory conditions, this phenomenon can last for several hours. The mechanism of this light emission still remains a mystery. One explanation is based on heating by shock wave compressions. Attempts are being made to verify the formation of a shock wave inside the bubble. The existence of a shock wave may prove that the high temperature caused behind the shock wave may be responsible for the light emission. Inorder to determine the governing mechanism, a flow measurement technique known as laser velocimetry was used to "map" the sound held around the bubble. It is hoped that comparison of the sound fields during light emission and in the absence of light emission will give some leads to determine the mechanism behind this phenomenon.

To achieve a significant increase in the accuracy of geolocated data products, next generation laser altimeters and planetary terrain mappers will require the use of pulsed laser sources with repetition rates of several kHz. Higher laser repetition pulse rates generally lead to smaller laser "footprints". A contiguous swath of footprints will then provide the data necessary to make a thorough 3-D topographical map. As the footprint size decreases the horizontal and vertical accuracy of the derived map increases. Critical to altimetric data precision is the rise time and pulse width of the laser output. Pulse widths of less than 5 ns are now desired but the microJ energies associated with these pulses would not allow for a usable ground return. To provide the necessary mJ pulse energies required for next generation systems, a new kind of solid state laser amplifier is investigated. This compact optical amplifier, passive in design, is regenerative and laser diode pumped. There generative nature of the amplifier is achieved by building an optical cavity consisting ofretro reflectors and lenses with a laser crystal residing in the center. A precise lateral displacement of one reflector produces an unstable cavity which inhibits lasing, but provides an input and output point for an injected laser pulse to enter, exist for a predetermined number of passes and then exit. Each pass through the cavity then imparts energy to the pulse, with the gain dependent on the energy density of the diode pumped crystal and the number of passes.

Aircraft flying at high angles of attack experience strong side forces, which may cause the pilot to lose control of the aircraft. Experiments in a wind tunnel with a stationary model have demonstrated the ability to control the side force with very low levels of suction. The same type of side force will cause an aircraft model in a wind tunnel to rotate on a sting, which is known as the coning-motion. The same suction techniques were employed to control the rotation of the coning motion model with a tangent o-give type nose cone. Suction was applied through two holes located at the tip of the nose cone. Several experiments were performed involving different control settings and different wind tunnel speeds to explore and analyze the feedback from the model. The rotating rate data was acquired with an optical encoder located at the end of the shaft. The encoder measures angular velocity and angular acceleration.

Two pressure transducers located at the nose cone provide the feedback signal to the control computer, which adjusts the suction in order to control the motion of the model.

This research endeavor intends to understand the unique air flow conditions which leads from transition to turbulence on elliptical nose cones. This air flow will be tested at hypersonic speeds between Mach 6 and Mach 9 and at a maximum temperature of 900 degrees Fahrenheit. Past research has attempted to understand this phenomenon. Those experiments used flat plates and circular cones which only account for two dimensional flow conditions. However, the air flow over an elliptical nose cone provides three dimensional measurements which are more realistic. In order to understand the transition to turbulence flows on elliptical nose cones at hypersonic speeds, a model of this nose cone will be tested in the NASA Langely Research Center. However, the model, the mount, and the measuring devices must be designed. This part of the project involves designing the "sting"--the part of the mount that hangs from the strut and holds the cone in position. When designing the "sting", the forces, stresses, and the temperature which affect the beam, behave differently under such high speeds. All these conditions are being considered for the design of the sting.

The study of the flow in turbomachinery is important to investigate because it directly affects the efficiency and heat transfer of the rotating blades in each stage of the machinery. As the air passes through the several stages of turbo machinery, wakes are produced by the rotating blades. The wakes cause the air to undergo boundary-layer transition from laminar to turbulent flow. Where this transition and separation of flow on the blade occurs is what affects the efficiency and heat transfer of each stage. There exists a periodic oscillation between laminar and turbulent flow that is affected by the wakes produced from the rotating blades. An examination of the frequency of periodic oscillation was investigated.

A simulation of the periodic wakes was produced by a rotating wheel that contained rods spaced 15 degrees apart. The rods passed through the air stream, and created a wake at the leading edge of the test section. The speed of the rotating wheel was varied in order to change the frequency of the rods passing through the air stream. Measurements were taken at different lengths from the leading edge of the test section. As the frequency increased, the overall shear stress as well as the occurrence of turbulent flow increased.

This poster describes one component of an interprofessional project for the development ofa fiber-optic pH sensor. This sensor is based on changes in the optical density of pH indicator solutions due to changes in environmental pH. The use of optical fibers allows the sensor to be employed in remote environments where conventional electronic sensors maybe impractical due to electromagnetic interference or corrosion effects of harsh conditions. We describe the design of the fiber-optic system, fabrication of the sample cell, andexperimental measurements of early prototype performance.

This poster describes one component of an interprofessional project for the development of a fiber-optic pH sensor. This sensor is based on changes in the optical density of pH indicator solutions due to changes in environmental pH. The use of optical fibers allows the sensor to be employed in remote environments where conventional electronic sensors maybe impractical due to electromagnetic interference or corrosion effects of harsh conditions. Our research consisted of two tasks: (1 ) characterization of pH indicators with measurements of optical density versus optical wavelength and solution pH, and (2) studies of gel systems for the containment of indicators in robust sensor systems. In this work we are also developing a database system for easy access to optical characterization data by all groups involved in the project.

This poster describes one component of an interprofessional project for the development ofa fiber-optic pH sensor. This sensor is based on changes in the optical density of pH indicator solutions due to changes in environmental pH. The use of optical fibers allows thesensor to be employed in remote environments where conventional electronic sensors maybe impractical due to electromagnetic interference or corrosion effects of harsh conditions. This group is involved in the design of the electronic power supply system, light sources, and optical detectors. We also designed the analog amplification, analog-to-digital conversion, digital voltage-to-pH conversion, and display driver modules. The prootype systememploys TTL logic while the production unit will be designed for CMOS logic for reduced power consumption under battery power.