The use and evaluation of cleaner wicks to accelerate in situ bioremediation of organically contaminated groundwater and soil

The adaptation of Cleaner Wicks to accelerate in situ bioremediation of organically contaminated ground water and soil can be accomplished by making minor modifications to the Cleaner Wick design. Once these changes in the Cleaner Wick design have been made the two primary ingredients necessary for aerobic microorganisms, nutrients and oxygen, can be delivered via the Cleaner Wick to the subsurface environment both above and below the water table to stimulate microbial growth and activity. Therefore, the microbial population will be able to biodegrade the target contaminants, rendering them harmless products such as carbon dioxide and water. An adequate understanding of the microbiological environment is necessary to achieve any type of success in bioremediation. Other factors that must be considered are subsurface temperature, pH, redox potential, site characterization, and possible inhibitory (i.e., competitive) microorganisms present

Development of a centrifugal microfluidic device for separation and sorting in biological fluids

A wide interest in employing micron-scale, integrated biochemical analysis systems for economical and rapid diagnosis has been the principal motivation behind this project. Low operating costs, portability and fast diagnosis times make centrifugal microfluidic devices an attractive option in patient-side diagnostics. Some essential tasks to be performed in microfluidic devices are sample-reagent transport, mixing, separation and detection. All these tasks require precise control of the RPM and spinning time. Centrifugal micro-fluidic platforms have been successfully implemented for detection of hepatitis A, tetanus, as well as for measurement of haemoglobin and hematocrit, for DNA analysis, and for assessment of cardiac disease etc. by assaying biological fluids like blood, saliva, and urine. This thesis presents the construction, including the micro-machining and testing of a multi-channel centrifugal microfluidic device for point-of-care (POC) diagnostics. A low cost device capable of delivering controlled revolutions per minute was made by modifying a CD-ROM drive and a polymer disk was used to handle the fluids. A network of microfluidic channels and reservoirs was fabricated on the CD by using a rapid prototyping method. The reservoirs hold the biofluid sample, meter the volume of fluid accurately and also serve as a component of capillary burst valves to gate the flow of fluid. Micromachining techniques like photolithography, wet-etching have been discussed for mass production of the prototype used for this research. Theoretical analysis of the burst frequency for passive capillary valves is reported and compared with practical results. The goal of this thesis was to develop a low cost device and demonstrate its use in the separation, and metering of plasma from blood using centrifugal microfluidics. One challenge when using blood for diagnosis is to separate the blood plasma from the rest of the blood cells. Concepts of blood centrifugation and particle displacement on a spinning disk have been employed to calculate the required RPM. Experiments were carried out on various geometries in order to achieve the maximum level of separation. The results of these experiments have been reported. It has been established that centrifugal microfluidics can be used to accurately control the flow of fluids in microchannels and this can be used for reliable low cost point-of-care diagnostics

The evolution of a tailored communications structure : the topics system

A computer-based human communication system should be designed for people\u27s use, in response to their perceived needs and communications styles; no single system can meet the needs of all groups and individuals. It might seem that a general electronic mail or computerized conferencing system with a standard set of features should be able to meet most communications needs, in much the same way that the telephone system meets the needs of a wide range of users. However, there are many communications structures found in everyday life, ranging from one-to-many news broadcasts, to the many-to-many patterns of town meetings, from the unstructured and informal gatherings at the local pub, to highly structured meetings using Robert\u27s Rules of Order. Each of these is an example of a specific communications structure appropriate in some circumstances and quite inappropriate in others. Within a flexible computerized conferencing system such as the Electronic Information Exchange System (EIES), it is possible to tailor the features of the system to the needs of the users, rather than forcing them to adapt their communications behaviors to the system and its limitations. Current concepts and structures such as electronic mail and conferencing will be supplemented in the next decade by an ever-increasing array of specially designed structures to meet specific needs. Hiltz and Turoff (1978) discuss some of the promises and potentials for how human communication via computer will transform the ways we work, play, learn, and govern ourselves. They also discuss in some detail a variety of communications structures designed for group problem-solving and decision-making. The major question addressed here is how these communications structures evolve. How are they initiated? Where do they lead? What forces govern their evolution? For a structure to be effective, it must meet the needs of the group using it. However, the perceived needs of a group may (and probably will) change over time. This means that as a group\u27s needs change, either as it learns more about the medium or as its situation changes, the communications structure must EVOLVE to match those needs. Thus, the process of designing and implementing a communications structure becomes an ongoing process. Since it is generally recognized that the microelectronics and telecommunications wave of change we are now beginning to experience (Toffler, 1980) will transform the very fabric of our society, and since the communications procedures and structures we use in this electronic medium are going to evolve very rapidly in the next two decades, an understanding of the process of this evolution seems critical for our successful transition to a post-industrial, communications-era society. A model of the ongoing process or design of these structures is introduced in Johnson-Lenz (1980c). Included there is the concept or GROUPWARE—the integrated, systemic whole made up of a group\u27s processes and procedures, PLUS software to support those processes and procedures. Most specific software structures can be used in a variety of ways, depending on the characteristics of the group and its perceived needs for process. Thus, the system which evolves is not only the computer software but also the process and procedures followed by the group to achieve its purposes, with or without software support; hence the term GROUPWARE. This paper traces the evolution or a particular communications structure, the TOPICS system, as well as the evolution of several groups using that system, each with its own unique and evolving groupware supported by the TOPICS software, and each contributing its own unique set or needs to the evolution or the software. The TOPICS system, resident on EIES, was designed and developed by the authors, in collaboration with the groups using it

Development of an integrated photonic sensor for monitoring hazardous organics

In this study, an integrated photonic sensor has been designed and fabricated for the purpose of monitoring hazardous organics in the environment. The operation of the sensor is based on the principles of the Mach-Zehnder interferometry. The sensor consists of a patterned waveguide structure made of phosphosilicate core and silica cladding. LPCVD processes were developed to produce undoped cladding and doped core silicon dioxide films. Diethylsilane (DES), Trimethylphosphite (TMP) and oxygen were used as the precursors for the deposition process. The effects of the O2/DES ratio and deposition temperature on the properties Of SiO2 films were investigated. It was observed that the oxide films deposited in the temperature range 550- 700 ºC followed an Arrhenius behavior with an apparent activation energy of 10 KCal/mol. It was found that the optimum conditions to synthesize underlying silicon dioxide films were 775 ºC, 200 mTorr and oxygen to DES flow ratio was 10: 1. After 20 hours deposition time under such conditions, the oxide film was ~15 μm thick, stress was compressive with a value of ~20 Mpa, and the refractive index was 1.458. The effect of TMP flow rate on the properties of PSG films was also studied. The composition and refractive index of PSG films varied with temperature and TMP flow rate. Optimum conditions to deposit PSG core layer were found to be at 600 ºC, 250 mTorr, 2 sccm TMP flow rate and an oxygen to DES flow ratio of 10:1. After 5 hours deposition time under such conditions, Phosphosilicate layer was about 7 μm thick, stress was compressive with a value of I Mpa, the refractive index was 1.466, and phosphorous oxide was ~7.5 wt%. The growth rate varied with TMP flow rate and exhibited a maximum value of 254 Å/min at 2.5 sccm and 600 ºC. PECVD processes were used to synthesize the upper cladding silicon dioxide films. The deposition conditions were 250 ° C, 900 mTorr, N2O flow rate 900 sccm, and 400 sccm SiH4 (3%) flow rate. After 30 minutes deposition time under such conditions, the oxide film had a thickness of 1.2 μm, stress was compressive with a value of ~110 Mpa, and the refractive index was 1.453. For all deposits, FTIR spectroscopy showed that no carbon was present in the deposits while UV/visible spectroscopy indicated better than 99% optical transmission. Optical analysis proved this integrated photonic sensor could be used as a prototype to monitor the hazardous organics in the environment

Design, fabrication and characterization of infrared filters

In-situ temperature monitoring, mapping, and control have become significant in semiconductor processes. Temperature of these processes can be measured by making use of the thermal emission from substrates in the infrared region. Various methods have been proposed to provide multicolor infrared detection. One such method involves placing segmented infrared filters close to the focal plane. The present study aims at gaining an insight into the design, fabrication and characterization of infrared filters. Filters were designed and fabricated with peak transmission at 1.5, 3.0, and 4.5 m. Extensive spectroscopic studies, using FTIR spectroscopy, have been performed in the infrared region, on the materials chosen for the filters - Si, SiO2, and Al2O3. The spectral transmittance characteristics of the filters have also been studied using optical spectrometry to monitor their performance at the desired wavelengths

The individual investor : investment objectives, strategies, and tactics

The individual investor\u27s circumstances and investment behavior have received relatively little attention since it was discovered in the late sixties that he was withdrawing as a direct participant in the American equities market. The first major response to this withdrawal phenomenon was the 1974 Individual Investor Research Project (IIRP). For the first time, the individual investor\u27s circumstances and decision processes were examined directly and not through broad-based trading statistics or portfolio simulations. This current survey identifies the significant changes in investment objectives, strategies, and tactics since the IIRP. These changes were discovered when seven demographic variables were cross-classified with various investment behavioral characteristics from a sample of 130 individual investors. This research effort also identifies the socio-economic characteristics of the individual investor that serve as significant influences on investment behavior