The cellular slime mold Dictyostelium discoideum is a simple eukaryote that has been used as a model organism for the investigation of eukaryotic cell signaling, regulation of gene expression, and development. Transcription of the gp-2 gene is induced during development and is regulated by extracellular morphogens such as cyclic AMP (cAMP; Sucic et al., 1993) and differentiation induction factor (DIF; Yin et al., 1994a). These morphogens are known to be involved in regulating cellular differentiation and pattern formation in the multicellular development of Dictyostelium. This makes the gp-2 gene a good candidate for the investigation of the mechanisms of regulation of gene expression during cellular differentiation. The gp-2 gene has been cloned and previous analyses of the promoter with 5' deletions have revealed the presence of several regulatory regions which contain repeated sequence elements; TA-boxes, the TAG-boxes, and C-boxes (Sucic et al., 1993; Rutherford et al., submitted). The C-rich regulatory region contains two C-box repeats and is the most proximal of the regulatory regions. The aims of this investigation are the precise definition of regulatory elements within the C-rich regulatory region and identification of the role played by these sequences in the transcriptional regulation of the gp-2 gene. The effects of disrupting regulatory sequences within the C-rich region with upstream regulatory elements intact were investigated using internal deletions and site-directed mutations. Using the luciferase reporter gene system it was shown that site-directed mutation of the downstream C-box (CB-2) and adjacent bases results in a 50-fold decrease in the developmentally induced luciferase levels compared to a wild-type promoter construct (OS). An internal deletion of this mutant construct that deletes the upstream Cbox (CB-1) and intervening sequences has no further effect on levels of expression induced during development. These data suggest that CB-2 and adjacent sequences are the regulatory sequences within the C-rich region that are involved in the transcriptional regulation of gp-2. The mutant promoter constructs regulate gene expression during development with the same temporal profile as the wild-type construct indicating that these sequences are not involved with the timing of induction of expression of the gp-2 gene. The induction of the gp-2 promoter constructs by extracellular cAMP was analyzed. The wild-type construct was induced approximately 10-20-fold by extracellular cAMP. However, the site-directed mutated promoter construct was not induced by cAMP under the same conditions. This suggests that CB-2 and adjacent sequences are involved with the induction of gp-2 expression by extracellular cAMP. Previously, 5' deletion analyses have shown that upstream regulatory elements are involved in cAMP-responsive expression of the gp-2 gene (Sucic et al., 1993). The data presented here indicate that the regulation of expression of the gp-2 gene by extracellular cAMP also requires sequences in and around CB-2. / Master of Science

Three genes encode identical calmodulin proteins in mammals. One possible reason for this unique situation is that it allows differential regulation of calmodulin gene expression. In order to study the promoter regions of the different genes, the 5’ ends of three mouse calmodulin cDNAs were isolated using a modified 5’ Rapid Amplification of cDNA Ends (RACE) method. Using these cDNAs as probes, the promoter regions of the Cam I and Cam III genes as well as a Cam II pseudogene were isolated from a 129SVJ mouse genomic library. When the Cam II cDNA was used to determine the chromosomal location of the Cam II gene, the results indicated that at least two likely pseudogenes exist in addition to the functional gene. Using a probe that contained only sequence from the promoter region and first intron of the Cam II gene, the chromosomal location of the bona fide Cam II gene was identified. Evidence indicates that conflicting growth signals in cells can lead to apoptosis. To determine if calmodulin, a proliferation signal, would induce apoptosis in cells cultured in differentiation conditions, C2C12 myoblasts were transiently transfected with a calmodulin expression vector. Half of the transfected cells were treated with calcium ionophore to determine if the calcium levels would have an effect. Overexpression of calmodulin did not lead to apoptosis, and the calcium ionophore caused death of the control- and calmodulin-transfected cells. / Master of Science

This work investigates power flow and energy transfer in controlled structures. If the goal of control is to stop an initially vibrating structure, energy must be forced out through dissipating components. The analysis performed here quantifies energy being transferred internally and externally to dissipative mechanisms in the primitives of a spring-mass-damper system and a beam-piezoelectrics-electronics system over the transient period of the systems’ response to initial conditions. The systems studied were broken down into capacitive, inertial, resistive and sourcing primitives. All systems containing primitives from all domains can be modeled this way. The analysis started from first principles and investigated energy flow in general. Energy flowing from the mechanical primitives to the electrical primitives is especially important because controlled structures often integrate primitives from these two domains. Computer simulations showed that power seemingly flows into sources used to control the structures. This work also laid the groundwork for the development of control design methods based on energy flow. / Master of Science

This study investigated the peak shaving and pollutant removal performance of an underground stormwater detention facility. The facility was located beneath the parking lot of a retail shopping mall in Prince William County, Virginia. The study methodology incorporated automatic inflow and outflow monitoring stations containing flow metering and automatic sampling equipment. The flow metering equipment continuously monitored flow rates, thereby making it possible to describe the inflow and outflow hydrographs. The automatic sampling equipment collected equal volume - variable time composite samples of runoff, making it possible to determine the inflow and outflow event mean concentrations of various pollutant constituents. Twenty runoff events were monitored between April, 1993 and January, 1994. The inflow and outflow hydrographs were compared to determine peak shaving performance. Due to the large volume of groundwater infiltration into the facility, which altered the inflow and outflow behavior, only 15 events were used in the peak shaving analysis. The inflow peak discharges for the 15 events were substantially less than the two year design storm used for the facility. To determine peak shaving performance at higher flow rates, design storms with greater peak flow rates were routed though the facility using the inventory method. The resultant peak shaving performance was similar to performance estimates in the facility design specifications. In fact, the facility actually reduced peak flows somewhat more than anticipated due to an outlet orifice that was constructed smaller than the design specified. To determine pollutant removal performance at the facility, inflow and outflow event mean concentrations for the various pollutant constituents were compared. A subset of 10 events was used in this analysis because of sampling equipment failures that resulted in insufficient distribution of sample aliquats over a runoff event. Seven different methods of quantification were used to estimate pollutant removal performance. Results indicated that, generally, the facility design and operational protocol provided little or no pollutant removal for most constituents monitored. The trace metals lead and copper were removed more consistently than any other constituents. Zinc was removed somewhat less than either lead or copper, probably because the storage pipe, being made of galvanized steel, was a source of zinc. / Master of Science

Experimental spatial dynamics modeling is a new method used to obtain a dynamic model of a harmonically excited vibrating structure. The continuous three-dimensional, complexed-valued velocity field of the structure is solved from a weighted least-squares finite element formulation, making use of high spatial density data obtained from a scanning laser Doppler vibrometer. Analytical expressions for the first- and second-order error sensitivity of the obtained model with respect to model parameters of the finite element model are developed. A frequency response analysis, resulting in a pseudo-dynamic stiffness matrix and the direct method of differentiation are used to obtain the required sensitivities. These sensitivities may be used to update the parameters to obtain a more accurate model, and also to yield a signal-to-noise level for which the data must be obtained. Analytical expressions are also developed for the first-order error sensitivity of the obtained model with respect to the spatial variables (position and orientation) of the laser. A parametric representation of both the laser beam as well as the surface of the structure is used. A variation in the spatial variables of the laser leads to a shift in the measured velocity, compared to the analytical model. The influence of changes in the spatial variables on the accuracy of the model is thus crucial. Once again, the results obtained may also be used to yield a signal-to-noise level for which the data must be obtained. The formulations developed are examined by making use of a theoretical model of a beam structure with out-of-plane harmonic excitation. / Master of Science

The objective of this research is to perform an in-depth study of the force components within the H25A compressor along with a computer simulation program and the dynamic response analysis of the compressor internals using the finite element method. The model tor force prediction was created based on the assumption that the frame of the shell structure is rigid and the subassemblies within the shell behave as one lumped mass. Springs are the connections between the shell and the subassemblies. Various parameters of the model were entered through the preprocessor of the simulation program which provides a series of data entry forms. The processor part of the program contains several modules for performing different tasks, such as the eigenanalysis, kinematic force computation. displacement/velocity/acceleration prediction, spring-end force calculation and variable-speed motor simulation. The simulation program also features post-processor functions in order to display the results of the analysis in plots, tables or with animation. Further research was focused on the correlation of the predicted force and orbit with the observations. With a finite element model of the full compressor. the spring-end forces due to the excitation at mass center were obtained from the dynamic response analysis and compared to the force gauge measurements. The excitations included the enforced displacement at the mass center which was regenerated from the accelerometer measurements. and the superposition of the kinematic forces and equivalent valve impact forces at the mass center. / Master of Science

The reanalysis of data obtained from the experimental study of two different trailing vortex pairs has been conducted to obtain a more complete understanding of the turbulence structure of these flows. Statistical and spectral results, as well as filtered results and estimates of the effects of vortex wandering on the characteristics of the flows are presented. The results of the vortex pair are compared with the data from the experimental study of an isolated vortex conducted under similar testing conditions and model configuration to distinguish between the structure and effects of the the separate vortices from those of vortex interaction. The analysis of a counter-rotating vortex pair reveal that initially the vortices develop in a manner similar to an isolated vortex. The cores appear laminar and the turbulence structure outside them is dominated by the spiral wakes. After some distance, flow inside and outside the cores becomes much more turbulent. The cores begin to grow and decay. The results indicate that this change may be a result of wave instabilities developed in the cores. The analysis of the co-rotating vortex pair reveal that turbulence is present in the cores as they spiral about each other and move downstream. After a certain distance the cores merge into a single core, which contains more turbulence and is over twice the size of the pair that created it. As merger comes to completion, a symmetric core is formed which has much less turbulence. Merger appears to cause an increased rate of vortex decay. / Master of Science

Despite the widespread use of night vision imaging systems in today’s military, the problem of directly measuring the spatial frequency response of these systems has been ignored. Modulation Transfer Function (MTF) performance specifications have been extensively researched for the components of night vision imaging systems such as the lenses and the image intensifier tube. The current method for calculating the system MTF is to combine the MTFs of all the components of the imaging system. Little research has been performed to directly measure the MTF of the entire system. This thesis describes a method to directly measure the modulation transfer function for an AN/AVS-6 Aviator’s Night Vision Imaging System (ANVIS). This method is based on the traditional slit technique and uses a Photo Research PR-900 video photometer as the detector. Comparisons between the direct measurement and the component combination calculation demonstrate the accuracy of the direct measurement. / Master of Science

This research investigated the formation potential (FP) for haloacetonitriles (HANSs), haloketones (HKs), chloropicrin (CP) and trihalomethanes (THMs) under conditions of constant DOC, constant Cl:DOC ratio, variable [Br] and variable apparent molecular weight (AMW) for coagulated water from a full-scale water treatment plant. Coagulated, high humic water (4.5 mg DOC/L) was fractionated into <1K, <10K, and <30K MWCO fractions. The DOC of the fractions was adjusted to the same value (e.g., ~ 2 mg/L). Fractions were chlorinated at 3:1 Cl,:TOC ratio under varying [Br]. Observed, non-THM species occurred at low concentrations (<0.3-9.0 ug/L). As expected THMFP speciation was strongly affected by Br:Cl ratio; this research demonstrated similar effects on specific HANs and HKs. Increasing quantities of brominated HANs and HKs were observed with increasing [Br]. DCANFP remained relatively constant while BCANFP and DBANFP increased with increasing [Br]. Increases in brominated species resulted in a larger relative change in THANFP than TTHMFP, suggesting that more HAN precursor material reacted when Br was present. Elevating Br:Cl to 0.03 resulting in HANFPs comparable to CHBr,FP. Change in HAN and HK species with respect to molecular weight cutoff (MWCO) and coagulated-raw water comparisons suggest that HANFP results from reaction with small, reactive, nitrogen containing compounds (<1K AMW) and larger (<30,000 MWCO) proteinaceous matter. / Master of Science

A hermetic reciprocating freon compressor was instrumented for noise transmission path identification. A mix of force gages, pressure transducers, and an accelerometer were installed to identify the main transmission paths. Triaxial force gages were installed and calibrated to measure the three forces transmitted from each suspension spring to the shell. The three triaxial force gages, along with a pressure transducer measuring the dynamic pressure inside the shell, were used in a multiple reference frequency response function (FRF) analysis with the sound pressure from an external microphone as the reference output. The multiple reference FRF analysis indicates that the suspension springs are the dominant noise transmission path in this compressor. A scanning laser velocimeter was used to measure the operating shape of one of the compressor harmonic responses. This harmonic shape was interesting because it is a significant sound radiator at a frequency well below the first structural mode identified by both experimental modal and finite element model analysis. The vibration pattern appears to be a combination of rigid-body motion of the compressor shell in response to the orbiting spring forces and a circumferential acoustic mode inside the shell. The sound intensity pattern radiated by a regular version of the same compressor model closely resembles the vibration pattern driven by the rigid-body motion. This indicates that the spring forces actually drive the sound radiation at this frequency. / Master of Science