Friday paper presentations.
** Denotes student "in progress" research
Section I: Biological Sciences
Health Sciences Building, Room 144
Paul Arnold, Presiding
2:00 AN ASSESSMENT OF THE MOBILITY OF STEM LOOP DNA IN NATIVE AND DENATURING POLYACRYLAMIDE GELS", Holly R DuPlain* and A.C. Spencer, Georgia Regents University, Augusta, GA 30912. Stem loop DNAs are single stranded oligonucleotides composed of a complementary stem region and a single stranded loop region. Several stem loop constructs consisting of either ten or twenty base pairs in the stem region and variable numbers of nucleotides in the loop region were studied to determine mobility through native and denaturing polyacrylamide gels. Due to its compact structure, stem loop DNAs run farther through native polyacrylamide gels than a single stranded oligonucleotide of the same length. Early observations of the behavior of the stem loop DNAs on denaturing gels indicate that stem loop DNAs with larger stem:loop ratios resist denaturation on traditional denaturing polyacrylamide gels. We are currently investigating the use of increased concentrations of urea and formamide as denaturants in gel electrophoresis to determine the optimal conditions for denaturing stem loop DNAs on polyacrylamide gels.
2:15 MORPHOLOGICAL AND ULTRASTRUCTURAL CHANGES USING ESSENTIAL OIL VAPORS AGAINST ASPERGILLUS FLAWS IN GEORGIA PEANUTS, Reesheda T. Gilbert * and RN. Achar, Department of Biology and Physics, Kennesaw State University, Kennesaw, GA 30314. Essential oils have been shown to display antifungal properties and could be a natural alternative to synthetic pesticides. Cinnamon and clove oils vapors may inhibit growth of A. flauus causing morphological and ultrastructural changes. Their antifungal activities were tested using the poisoned food method and their efficacy determined by zones of inhibition and analyzed by t-tests. Pure cultures were maintained on a potato dextrose agar plates. Various serial dilutions ranging from decreasing to increasing increments were prepared for each oil vapor, inoculated separately onto a sterile filter paper disk, and placed in an evaporating crucible. These crucibles then covered with an inverted PDA plate containing 10 [micro]L of spores and placed in a double sealed vapor chamber to prevent dissipation. After incubation, zones of inhibition were measured. The concentration at which a 15mm zone was observed was considered the minimum inhibitory concentration (MIC) for that particular oil vapor. A zone of 18mm or greater indicated the minimal fungicidal concentration (MFC). The MIC of Clove oil vapor was 1100ppm after 48 hours of exposure while the MFC was 2300ppm after 96 hours of exposure. Cinnamon oil vapor showed an MIC of 2300ppm after 72 hours of exposure and MFC of 2500 ppm following 96 hours of exposure. Statistical analysis resulted in a p-value of 2.07E-7 showing a significant difference between the two vapors in their antifungal properties. Electron micrographs showed damage to hyphal walls and conidiospores and disorganization of cell organelles.
2:30 ASSESSMENT OF VEGETATIVE CHARACTERISTICS FOR RESTORATION OF CRITICAL SANDHILL HABITAT AND CONSERVATION OF THREATENED REPTILE SPECIES", Regan A. Phillips * (1), M. Elliot (2), L.M. Kruse (2), J.M. Moffett Jr. (2), C.J. Tant (2) and B.L. Simmons (1), (1) East Georgia State College, Swainsboro, GA 30401 and (2) Georgia Department of Natural Resources, Nongame Conservation Section, Social Circle, GA 30025. In the Ohoopee Dunes Natural Area, restoration is ongoing to promote critical habitat and improve vegetative characteristics beneficial to the gopher tortoise (Gophermus polyphemus), a state-listed threatened species. The burrow of the gopher tortoise is utilized by a variety of native wildlife, making the tortoise a keystone species in sandhill habitats. The Ohoopee Dunes Natural Area is part of Georgia s most extensive riverine sandhill formation, with particular plant and animal communities adapted to the unique habitat characteristics. Randomly placed transects throughout suitable habitat were surveyed for gopher tortoise burrows. Each burrow found was measured, located with GPS, and scoped with a camera system to determine occupancy. Plant species were identified every 2 meters along 50 meter transects selected using GIS. This project will use monitoring data collected by the Georgia Dept, of Natural Resources, with assistance by the author, to quantify herbaceous cover and describe key indicator species that are either desirable or undesirable for restoration of critical habitat. These data are important for long-term monitoring by the Georgia Dept, of Natural Resources in order for them to determine if the current routine of burning is effectively sustaining or increasing the current tortoise population and decreasing the undesirable tree species in the area. Data on pre-treatment vegetative community structure and current tortoise populations will be presented.
2:45 DRILLING FREQUENCY OF CERITHIUM SPECIES IN THE BAHAMAS, Elizabeth Lemley * (1), M. DeVore (1) and D. Freile (2), (1) Georgia College & State University, Milledgeville, GA 31061 and (2) New Jersey City University, Jersey City, NJ 07305. Studies of boring gastropods have largely focused on the drilling behaviors and patterns for Muricidae and Naticidae. Most of these studies examined the boring activity of these gastropods on bivalves. In the present study, we examine the frequency of drilling by naticids on the gastropod species Cerithium based on collections from recent death assemblages. Samples were obtained from the islands of Abaco, New Providence, and Sal Salvador Island in the Bahamas. The average drilling frequency for all sites on all three islands was 15%. For Abaco, 16% of the Cerithium species were drilled and the drillhole position was in the whorl above the aperture in 30% of the sample. Cerithium species from the New Providence sample had a drilling frequency of 12% with the drillhole positioned in all but one specimen, just above the aperture. Finally, 17% of the Cerithium samples from San Salvador Island were drilled and the position of the drillhole varied. Specimens from the New Providence sample were considerably larger than those from the other islands. The larger shell size, in conjunction with a strong preference in drillhole position, suggests that prey handling may play a role in determining the drillhole position. A second possibility is that species of naticids may select different size classes of prey.
3:00 OCTOPUS DRILLING FREQUENCIES IN TWO CARIBBEAN COWRIE SPECIES (EROSARIA ACICAULARIS AND LUCRIA CINEREA), Aeron Attwooll * and M. DeVore, Georgia College & State University, Milledgeville, GA 31061. Octopi often feed on mollusks and commonly drill the shells of prey. They then inject toxins into the drillhole before extracting the animal from its shell. When octopi consume gastropods they often, but not always, drill the shell. If the prey is drilled the hole is made in the region of the spire. In cowries (Family Cypraeidae, Subfamily Cypraeinae), the spire is generally concealed in mature individuals by the most recent shell growth. There are no reports documenting that octopi drill cowries in a preferred region of the shell. After examining and recording the position of drill holes in the two most common species of cowries in the Bahamas Lucria cinerea, (Atlantic Grey Cowrie) and Erosaria acicularis (Atlantic Yellow Cowrie), we found that there is indeed a preferred region of drilling. Shells were consistently drilled through the inner lip below the spire. In our studies we found that octopi strongly predate Lucria and only a single specimen out of 51 Erosaria shells was drilled. It appears that octopi display both preference in cowrie species consumed and also in the position where they drill these prey. It is not certain if octopi predate both species based only on the presence and absence of drilling. It is possible that octopi predate Lucria without drilling through the shell and use an alternative means to immobilize when feeding on this species of cowrie.
3:30 ALARM CUES IN PLANARIANS, Heather L. Perona *, J.L. Winkler and F.S. Corotto, University of North Georgia, Dahlonega, GA 30597. Planarians reportedly avoid a solution prepared by pulverizing a conspecific in 1 ml of water (the full-strength test solution). This finding suggests that damaged planarians release alarm cues, but we suspect that the full-strength test solution contains compounds at concentrations higher than would be found following predation. We analyzed planarian behavior when they were exposed to two test solutions that might be more realistic, a 10-fold dilution of the full-strength solution and a "poked" test solution in which an animal was placed in 1 ml of water and then stabbed 10 times with a pin. For testing, a planarian was placed in a hemisected, water-filled straw with cotton balls at both ends. A test solution was pipetted onto one cotton ball and a control solution onto the other. To determine preference between the solutions, the position of the flatworm was determined at 1-min intervals for 10 min. We also quantified lengthwise body contractions (scrunching) in response to the diluted test solution. Results confirmed previous findings that planarians avoid the full-strength solution, but we failed to detect a preference between the control and either the diluted or poked test solutions. Exposure to the diluted test solution, however, did lead to significantly more scrunching than exposure to the control. Scrunching could be the planarians' equivalent to freezing, a behavior exhibited by fish when exposed to alarm signals. If so, then planarians display alarm behavior in response to a more realistic predation cue than shown previously.
3:45 DOCUMENTING CHANGES IN MOTH LIFE CYCLE AND ABUNDANCE CAUSED BY URBAN WARMING **, Vy Tran * (1), Linh Do * (1), I.Y. Rickets (1), J. Pickering (2) and J.M. Lochamy (1), (1) Georgia Perimeter College, Clarkston, GA 30021 and (2) University of Georgia (Discover Life Group), Athens, GA 30502. The potential upward shift in global temperatures of as much as 5[degrees]C has been predicted to have major effects on species abundance and distributions. The average 5[degrees]C increase of nighttime temperatures in Atlanta relative to Athens presents a natural experiment to test such predictions on moth species. Deforestation and air pollution are also factors specifically affecting the lichen moth population. Moths were photographed arriving at porch lights at nine forested, residential locations in Metro Atlanta. Abundance and species richness data were compared to two sites in Athens. Atlanta showed fewer overall moth species and individuals. There was also a significant mismatch between the most common 20 moth species in both locations, with only 3 shared species making both lists and 11 of the most common Athens species absent from the Atlanta area. As expected, several of the most common species in Atlanta are absent in Athens, yet commonly seen in Florida. These observations show that large urban heat islands like Atlanta can be used to predict changes in community ecology that might occur as a result of global warming.
4:00 HABITAT PREFERENCES, ABUNDANCE, AND POPULATION CHARACTERISTICS OF A STATE-ENDANGERED CRAYFISH CAMBARUS PARRISHI ALONG AN ELEVATION GRADIENT **, S Weaver *, K Cash * and J.G. Davis, Young Harris College, Young Harris, GA 30582. Cambarus parrishi (CP) is a Georgia state-endangered crayfish which has been prioritized as in need of study by the state wildlife action plan. This multi-year study defined habitat preferences within 4 drainages at 13 sites in the upper Hiwassee River watershed. Habitat parameters were collected at macro- and microhabitat scales and included substrate size, depth, water velocity, stream roughness, stream width, and substrate composition. Correlation analysis identified habitat variables associated with crayfish presence and density, which will be incorporated into predictive habitat models. On a macrohabitat scale, CP density was significantly (a=0.10) correlated with percent gravel (P=0.017) and small boulder (P=0.0092) substrates. CP density varied significantly (P<0.001) between drainages with CP most abundant in the Corbin Creek drainage whereas the co-occurring Cambarus bartoni (CB) did not vary. Observationally, CP density tended to increase with elevation. On a microhabitat scale CP (n=141) presence was significantly correlated with distance to bank (P<0.01), percent cobble (P<0.001), percent gravel (P=0.006), and percent small boulder (P=0.004). Additional analyses will investigate habitat differences between CP and CB, seasonal change in reproductive form of male and female CP, and ecological distances of crayfish communities among sites.
4:15 A NEW TECHNIQUE FOR AGING THE SICKLEFIN REDHORSE MOXOSTOMA SP. TO MEASURE ANNUAL GROWTH RATES **, Benjamin A. Farley *, W.H. Leatherwood and J.G. Davis, Young Harris College, Young Harris, GA 30582. The sicklefin redhorse (SFR) Moxostoma sp. is a rare, potadromous species of Catostomid fish of Towns County that is currently under review for listing on the endangered species list. Status reviews rely on the best available scientific data but age data, which is used to estimate population survival, growth rates, and recruitment for SFR, is difficult to collect and usually involves sacrifice of sampled individuals. We tested the utility of aging SFR with pectoral fin rays, which is a non-lethal procedure, and compared estimated ages to ages obtained via scales. Scales and pectoral fin rays were analyzed with the use of a blinded method in which two readers did not know fish length or the other reader's assigned age. Whereas readers had high agreement in ages for scales, agreement for ages from pectoral fin rays was low (20%). However, as previous research found, scales appear to greatly underestimate SFR ages, especially for SFR older than 8 years. After readers agreed upon an age, annual growth increments were marked and measured with the use of Image J software. Yearly variation in annual growth will be compared to mean discharges and temperatures during the spring spawning season to determine if this affects growth. SFR are long-lived (the maximum lifespan is 23 years) and experience slow growth after reaching sexual maturity.
4:30 REIN TENSION DURING TROT AND CANTER IN DRESSAGE HORSES OF VARYING LEVELS **, Ashley Davenport (1) *, B.K. Hull (1), D.S. Hanson (2), J.G. Davis (1), and A. Roy (1), (1) Young Harris College, Young Harris, GA 30582 and (2) Safe and Sound Equine Services, Newnan, GA 30264. The dressage horse uses a combination of balance, suppleness, power, and obedience throughout all levels of dressage competition. Connection between horse and rider is achieved through the reins and use of rein tension. Excess rein tension shifts bit position and bit angle, changing oral behaviors in the horse and affecting the horse's overall ability to perform, therefore it is imperative to understand if rein tension varies for horses and/or riders of different levels. One objective of this research is to measure rein tension and determine if there is a difference in average rein tension between horse and rider combinations of different dressage levels. Another objective is to determine if differences exist between the individual rider's inside and outside reins. The rein tension was measured as the horse and rider completed a series of twenty-meter circles in both the clockwise and counter-clockwise directions. Each set of circles consisted of a full trot circle, followed by a full canter circle ridden in both directions. The Mark-10 tension sensor was first placed on the rider's left rein to complete the first set of circles at the trot and canter. The sensor was then placed on the rider's right rein to complete the second set of circles. Twenty-one horses of six competitive levels and 13 riders of five competitive levels have been measured with four more horses and riders to be completed. Preliminary rider results show that rider's dependence on the inside and outside reins not only reflects the rider's level, but the horse's level as well.
Section II: Chemistry
Health Sciences Building, Room 105
Ghislain Mandouma, Presiding
3:15 DETERMINING THE GLASS TRANSITION OF POLYSTYRENE NANOSPHERES UNDER HARD AND SOFT CONFINEMENT **, Nicole M. Sikes *, Rubicelys Torres Guzman and D. Wade Holley, Columbus State University, Columbus, GA 31907. The temperature at which a polymer undergoes a change from a brittle, glassy state to a rubbery, elastic state is known as the glass transition temperature ([T.sub.g]). The glass transition temperature is one of the most important characteristics of a polymer. Using temperature varied fluorescence spectroscopy the glass transition temperature of polystyrene nanospheres under both hard and soft confinement was determined. The nanoparticles were formed using semi-continuous microemuslion polymerization. In the case of hard confinement, the nanoparticles were added to an 18% SDS solution. For soft confinement, the nanoparticles were dialyzed.
3:30 EXPLORING SUPPLEMENTAL INSTRUCTION USAGE BY ORGANIC CHEMISTRY STUDENTS, Oneida E. Muniz * and Suzanne R. Carpenter, Armstrong State University, Savannah, GA 31419. Supplemental Instruction (SI) research has affirmed that it increases grades and retention rates in organic chemistry. However, factors affecting SI usage have not been explored. Our purpose was to try to determine the reasons why students do not utilize SI. In this study, SI instruction was available 3 hours a week outside of regular class time. Special events were designed and incorporated into the regularly scheduled SI sessions. Additionally, an extra credit set (with varied difficulty levels) was administered. The lecture students were surveyed after each exam to assess attendance practices, reasons for non-attendance, exam grade, and level of satisfaction with SI. SI attendance ranged from 1-13 students with special events causing a transient spike in attendance. The number one reason for non-attendance was a lack of need for help (even after failing an exam). For 67% of the students that did not use SI, work commitments were cited as the reason. Another interesting finding was that although 60% of the students enrolled in Organic Chemistry I are females this semester, 93% of the SI attendees were female. In summary, this research provides insight into two aspects of SI: why students don't attend and a gender differential in its usage at our institution. Perhaps some students begin the semester aiming for a C. An end of the semester survey is expected to provide insight on this. The gender differential was unexpected and will be explored in the future.
3:45 A NOVEL AND GREEN SYNTHESIS OF SUBSTITUTED BENZO[c] CINNOLINES AND DIBENZO[c,h]CINNOLINES AND THEIR CYTOTOXICITY SCREENING **, Tahera Nembhard * and Ghislain Mandouma, Department of Natural & Forensic Sciences, Albany State University. Benzo[c)cinnoline and its derivatives are important heterocyclic compounds with antirheumatoid, as well as antimitotic properties. These compounds can be accessed through biarylation of nitroaryls followed by diazotization. Biaryl compounds play an important role in medicinal chemistry and drug discovery. Synthetic methods of biarylation have been dependent on expensive transition metal catalysts as well as lengthy isolation steps often involving the use of toxic solvents. In order to circumvent these issues, a novel two-step synthetic method to prepare benzoic] cinnoline 18 and its chlorinated derivatives 19-22 as well as dibenzo[c,h]cinnolines 23-24 is proposed. The procedure is "green" involving no use of solvent or added catalysts for the first step of this novel Ullmann-type biarylation of halogenated nitroarenes (compounds 1-6) at room temperature. The following step is a classical diazo moiety forming cyclization at low temperature to generate the benzo[c]cinnolines 18-22 as well as the benzoic,h]cinnolines 23-24. The new procedure is suitable for self- and cross-coupling condensations demonstrating its general scope. Cross-coupling of different halogenated nitroarenes is moderate to high yielding in comparison to self dimerization as shown in the preparation of biarylated compounds 14-17. The yields of reactions are quantitative as no polymerization is observed in this solvent-less process.
4:00 DEVELOPING A CALIBRATION MATRIX FOR DETERMINING ACTIVES IN CHILDREN'S DIMETAPP USING UV DATA AND TARGET FACTOR ANALYSIS, Huggins Z. Msimanga *, Truong Thach Ho Lam, Mihyang Song and Newsha Tavakoli, Department of Chemistry and Biochemistry, Kennesaw State University, Kennesaw, Georgia 30144. Children's Dimetapp (CDT) contains brompheniramine maleate, phenylephrine hydrogen chloride, and dextromethorphan hydrogen bromide as active ingredients. It also contains excipients such as sodium benzoate, FD&C Blue #1, and FD&C Red #40, all of which are UV-active. Under such circumstances, spectral interference must be accounted for in the calibration matrix. A spiking technique, where the analytes are mixed with the sample to make up for interference was used. Trial calibration solutions were prepared, and any mismatch between the calibration and sample solutions spectra were monitored by calculating score plots using principal component analysis. The predictor model was calculated via target factor analysis, and tested with CDT and synthetic samples. In this talk, the results during the development of the calibration and the final results on real and synthetic samples are discussed. Based on the label claims of CDT, the final calibration matrix gave concentrations of 207mg/L [+ or -] 3 %RSD for brompheniramine maleate, 506 mg/L [+ or -] 1 % RSD for phenylephrine hydrogen chloride, and 958 [+ or -] 4 %RSD for dextromethorphan hydrogen bromide, all of which gave relative errors of less than 5%.
Section IV: Physics, Mathematics, Computer Science, Engineering and Technology
Health Sciences Building, Room 207
Hasson M. Tavossi, Presiding
1:00 TOROIDAL MOMENT CONTRIBUTIONS TO THE MULTIFERROIC ACOUSTIC SUSCEPTIBILITY, Alexander Price * and Trinanjan Datta, Georgia Regents University, Augusta, GA 30912. We consider the effects of toroidal moment corrections to the acoustic susceptibility tensor of a material that is simultaneously ferroelectric and a canted antiferromagnet (multiferroic). Using the Landau-Lifshitz equation of motion for the magnetization, the Landau-Khalatnikov relaxation equation for the electric polarization, and an equation of motion for the toroidal moment we analytically compute the corrections to the acoustic susceptibility tensor. In the presence of toroidal moment coupling we find that the previously vanishing susceptibility components in the multiferroic channel are now non-zero. Additionally, the toroidal corrections give rise to nonzero, asymmetric susceptibility components in the magnetic, electric, and multiferroic channels with both real and imaginary corrections to the susceptibility. Funding from Georgia Regents University Small Grants Program is gratefully acknowledged.
1:15 TRANSVERSE DISTORTION EFFECTS ON THE KASTELEYN AND KDP TRANSITION IN SPIN ICE, CurtisLee M. Thornton * and Trinanjan Datta, Georgia Regents University, Augusta, GA 30912. Geometrically frustrated pyrochlore oxides containing a rare-earth ion and a transition metal ion form a network of corner-sharing tetrahedra. Prominent examples include [Dy.sub.2][Ti.sub.2][O.sub.7] and [Ho.sub.2][Ti.sub.2][O.sub.7]. Magnetic frustration in these compounds suppresses the formation of a long-range ordered ground state resulting in an exotic phase of matter called spin ice. Elucidating the role of external perturbations such as pressure and magnetic field is an important step towards understanding the novel KDP and Kasteleyn phase transitions arising in these classical spin ice materials. Utilizing an analytical approach based on the Husimi tree approximation, we investigate the effects of both transverse and uniaxial pressure distortion of the spin ice tetrahedra on both the KDP and Kasteleyn transition in the presence of an external magnetic field. Compared to the uniaxial distortion scenario, we find that including the effects of transverse distortion leads to further suppression of magnetization and heat capacity in both the Kasteleyn and KDP cases.
130 MAXIMALLY EXPOSED OFFSITE INDIVIDUAL WORST-CASE SECTOR DETERMINATION FOR NESHAP COMPLIANCE AT THE SAVANNAH RIVER SITE, K.R. Moore * (1), R.A. Stahman * (1), G.T. Jannik (2), K.L. Dixon and J.R. Newton (1), (1) Georgia Regents University, Augusta, GA 30912 and (2) Savannah River National Laboratory, Aiken, SC 29808. The Environmental Protection Agency requires the use of the computer model CAP88 to estimate doses for demonstrating compliance with 40 CFR 61, the National Emission Standard for Hazardous Air Pollutants (NESHAP). The model requires the input of various parameters that influence how the radioactivity produced onsite is dispersed and distributed to the surrounding areas outside the boundaries of the Savannah River Site. The worst-case sector is the sector and distance where an individual would receive the highest dose due to a potential release from an onsite facility. The worst-case sector analysis addresses potential ground-level and stack releases from 20 operational areas. Weather patterns were analyzed at each of these areas relative to sixteen compass points over a five year time frame. The results of the calculations identified the 20 worst-case sectors that were compared to 16 worst-case sectors determined in 2009. An overall increase in relative air concentrations and changes in worst case sector distance and location were observed and will be discussed further in this presentation.
1:45 EXPLORATION OF THE INTENSITY SIGNAL OF A JDSU 1145P HELIUM-NEON LASER, Owen L. Angleton *, Jr. and Dr. Tom Colbert, Georgia Regents University, Augusta, GA 30912. The waveform from a JDSU 1145P He-Ne laser is analyzed to determine the amplitude and number of longitudinal modes present. Using a high bandwidth oscilloscope and high speed detector, we observe steady optical beats due to mixing of several longitudinal modes in the laser. The beats can be used to indicate specific longitudinal modes present in the laser. The signal is analyzed using a parameter grid search to produce numerical simulation of the signal. The grid search spans all possible relative longitudinal mode amplitudes assuming a symmetrical arrangement to the center frequency. A best fit analysis determines the mode structure. Finally, comparing this grid search result to the theoretical gain curve, the lasing threshold is determined to find that the signal as observed consisted of seven longitudinal modes with relative output amplitudes of 0.01, 0.33, 0.05, 1, 0.05, 0.33, 0.01.
2:00 DEVELOPMENT OF AN INEXPENSIVE TRACKING DEVICE FOR MOCK MRI TRAINING SESSIONS USING RASPBERRY PI **, J.C. Stephens * (1), J.A. Hauger (2) and N. Yanasak (2), (1), Davidson Fine Arts Magnet School, Augusta, GA and (2) Georgia Regents University, Augusta, GA 30912. Functional Magnetic Resonance Imaging (fMRI) studies are important for assessing brain activity of children participating in trials investigating the efficacy of exercise programs intended to mitigate symptoms of Attention Deficit Hyperactivity Disorder (ADHD). In order to ensure high quality fMRI experiments, a training protocol designed to reduce motion of participants during scanning is necessary. We have developed a simple electronic device for quantifying motion during training sessions. The system measures and tracks motion on the order of a mm using video capture technology interfaced to a Raspberry Pi computer. Participant motion is identified by computing the centroid of the edge detected image at a rate of approximately five frames per second. Short-term (~0.2 sec) and long-term (~5 minute) motion exceeding 2 mm is considered a trial failure and is used to guide participant training. The design, construction and effectiveness of the device will be presented.
2:15 INTERFEROMETRIC MEASURMENT OF THE THERMAL EXPANSION COEFFICIENT OF BK7 GLASS, Matt Herren * and Dr. Tom Colbert, Georgia Regents University, Augusta, GA 30912. A novel and simple technique is used to measure the linear thermal expansion coefficient of BK7 glass. This glass is typical material used for most visible range optics. The measurement technique uses reflection of Helium Neon Laser light from the front and back surfaces of the lens. The reflections form a simple Michelson-like ring interference pattern. The lens is inside an oven and heated, causing thermal expansion. An accurate measure of change in thickness of the lens can be determined by observation of fringes moving on the interference pattern. Our results yield [alpha]=(8.2 [+ or -] 0.4) x [10.sup.-6]/C[degrees] which is in good agreement with the standard value of 8.3 x [10.sup.-6]/C[degrees] for the temperature range investigated. In order to determine the thermal expansion coefficient, the index of refraction of the material must be known.
2:30 MEASUREMENTS OF LOW ENERGY GAMMA RAYS WITH MET ALS COMPARED TO LEAD FOR APPLICATIONS IN GAMMA CAMERA COLLIMATORS **, Thomas F. Lynam **, Jessica S. Robinson * and Gregory G. Passmore, Georgia Regents University, Augusta, GA 30909. Interactions between lower energy photons and K-shell electrons of different metals were viewed using a Sodium Iodide detector. In nuclear imaging, measuring a lower energy photon (Tl-201) in the presence of a higher energy photon (Tc-99m) is very difficult due to Compton scattering. Compton scattering is the emission of a characteristic X-ray due to a vacancy, caused by the ejection of an inner shell electron by photons, being filled by an outer shell electron. Pb is the most commonly used attenuator for gamma camera imaging. However, because of the interaction between Tc-99m's photons and Pb's K-shell electrons, interference is seen when measuring Tl-201 's photons due to the characteristic X-ray. Because of this interaction, various metals were tested to replace Pb as the attenuator in nuclear imaging in order to utilize a dual isotope method. A minimum number of counts were established to provide a 0.01% error. Calibration of the detector occurred daily with a Cs-137 rod source and Eu-156 rod source. Decay rates of the sources were taken into account through a cyclic rotation of the metals. Tungsten (W), Hafnium (Hf), and Lutetium (Lu) all provided better attenuation of the Tc-99m photons: W (10.9%), Hf (0.6%), and Lu (1.3%). Also instead of adding counts to the Tl-201 window, each metal attenuated photons in that channel: W (16.1%), Hf (1.8%), and Lu (3.0%).
2:45 PORPHYRIN-GRAPHINE OXIDE FIELD EFFECT TRANSISTOR BIOSENSOR **, Akilah I. Mateen * and Thomas A. Searles, Atlanta Metropolitan State College, Atlanta, GA 30310 This project details the fabrication of an aptamer-modified field effect transistor (FET), using a porphyrin-graphene composite and a silicone/silicon dioxide substrate. Both porphyrin and graphene oxide display a high sensitivity to electrochemical changes within cells. In order to create the composite, porphyrin is added to an aqueous solution of reduced graphene oxide and N,N-Dimethylformamide (DMF), resulting in a stable structure from its [pi]-[pi] bond. The FET is used to detect the presence of E6 and E7 proteins, viral proteins commonly associated with the development of HPV-infected cells into cervical cancer cells. By analyzing the change in resistance when the proteins bind to the receptor molecules attached to the composite, the concentration of the proteins can be measured and quantified.
3:00 Break (Posters on display until 5:30)
3:15 SIMULATION OF CUBESAT ORBITAL MOTION AND THE ITS POWERSUBSYSTEM **, DeAndre C. Penn * and Thomas A. Searles, Atlanta Metropolitan State College, Atlanta, GA 30310. A major limitation slowing the widespread use of CubeSat technologies is the lack of long lasting power sources available. We propose a new power subsystem incorporating the use of Li-ion super capacitors in conjunction with solar cells. Adding to the popular use of solar cells as a reliable energy source, super capacitors will theoretically add the element of recharge to the repertoire of CubeSats' power source. The weight of the capacitor, as well as other factors of the Nanosatellite including the effect on the total mass and space constraints, will also play a key part. Orbital rotation and time spent harvesting energy on all sides will be simulated using MATLAB software. A model will be created using 6V solar cells without the super capacitors to test the simulation in real life. The purpose of this experiment will ultimately be to test the capability of solar cells and li-ion super capacitors as alternative methods to long lasting power sources.
3:30 LOW COST SOURCE MEASUREMENT UNIT FOR THE CHARACTERIZATION OF DYE-SYNSITIZED SOLAR CELLS USING INTEL GALILEO DEVELOPMENT BOARD **, B. Erin Davy * and Thomas A. Searles, Atlanta Metropolitan State College, Atlanta, GA 30310. Solar energy is an abundant renewable resource which can be harnessed through many types of photovoltaic devices. One such device is a dye-sensitized solar cell (DSSC). DSSCs are electrochemical devices that use the electrolysis of water to mimic photosynthesis and are comprised of a sensitized photoelectrode (semiconductor) and a counter (catalytic) electrode. Commonly, platinum is used as the photocatalyst in the counter electrode because it possesses high catalytic activity, but the high cost of platinum puts it at an economic disadvantage. Graphene and other conductive polymers have also been used as an alternative, due to more cost effectiveness. Thus far, maximum efficiency acquired through DSSC applications is approximately 15% which is too low to be viable for economic applications. The efficiency of a solar cell can be tested through a source measurement unit. A source measurement unit, or source meter is capable of both applying a constant voltage or current source, as well as reading a voltage or current source from another device. In this study, a SMU will be constructed using an Intel Galileo development board and compared to one developed using an Arduino Uno Controller board. Using MATLAB, the Galileo board will be programmed to read and sort information given to it regarding the electron flow through the DSSC's counter electrode. As a result of this work, we have developed a characterization system for solar cells 5% of the cost of a commercial system.
3:45 MAXIMALLY EXPOSED OFFSITE INDIVIDUAL WORST-CASE SECTOR DETERMINATION FOR NESHAP COMPLIANCE AT THE SAVANNAH RIVER SITE, K.R. Moore * (1), R.A. Stahman * (1), G.T. Jannik (2), K.L. Dixon and J.R. Newton (1), (1) Georgia Regents University, Augusta, GA 30912 and (2) Savannah River National Laboratory, Aiken, SC 29808. The Environmental Protection Agency requires the use of the computer model CAP88 to estimate doses for demonstrating compliance with 40 CFR 61, the National Emission Standard for Hazardous Air Pollutants (NESHAP). The model requires the input of various parameters that influence how the radioactivity produced onsite is dispersed and distributed to the surrounding areas outside the boundaries of the Savannah River Site. The worst-case sector is the sector and distance where an individual would receive the highest dose due to a potential release from an onsite facility. The worst-case sector analysis addresses potential ground-level and stack releases from 20 operational areas. Weather patterns were analyzed at each of these areas relative to sixteen compass points over a five year time frame. The results of the calculations identified the 20 worst-case sectors that were compared to 16 worst-case sectors determined in 2009. An overall increase in relative air concentrations and changes in worst case sector distance and location were observed and will be discussed further in this presentation. Acknowledgements go to the Department of Energy for funding for this work
4:00 A SIMULATION AND MODELING OF REFLECTIVITY FOR TWO PERIOD BRAGG REFLECTOR **, Jared W. Thacker *, J. E. Hasbun and Ajith DeSilva, Department of Physics, University of West Georgia, Carrollton, GA 30118. The wave propagation in a periodically stratified medium, which we will call a stack for the sake of brevity, has many uses in applied physics and engineering. A complete theory of wave propagation can be derived using the theory presented in Principle of Optics by Max Born. We employed the theory to determine the reflectivity of a Distributed Bragg Reflector (DBR). A DBR is a one-dimensional photonic crystal consisting of alternating layers of different refractive index materials. The optical properties of a two-period DBR are studied here. Each period consists of layers of Polyvinyl Carbazole (PVK) and Cadmium Sulfide (CdS), which were constructed on a glass substrate. Further we used the Cauchy equation for the theoretical simulation of the refractive index for CdS in the wavelength ranging from 400-1000 nm. The calculations are performed using MATLAB and show the results of fitting the experimental data with the theory. The theoretical calculations predict that a center wavelength ~600 nm and reflectivity ~40 % for the two period DBR which is in good agreement with the experimental results. The authors would like to acknowledge the financial support from UWise and SRAP programs at UWG.
4:15 THE EFFECT OF PRESSURE AND TEMPERATURE ON THE ELECTRICAL RESISTANCE OF GRAPHITE AND NANODIAMOND **, Evan Reed *, Calleigh Hitt * and Ben de Mayo, University of West Georgia, Carrollton, GA 30118. We report on the results of a study of the effects of pressure and temperature on the electrical resistance of commercially obtained powdered graphite and nanodiamond materials. A 3-D printer is used to make the sample holders. Temperatures range from liquid nitrogen (-196[degrees]C) to room temperature (23[degrees]C). A 10 ton hydraulic press supplies pressures up to 40k lb./[in.sup.2] (3 MPa). A Labview virtual instrument measures the voltage drop across the sample, the current through the sample, the temperature and the pressure simultaneously at a rate of two times a second. The data are analyzed using Excel software. Work supported by the Georgia Space Grant Consortium-NASA.
4:30 STUDY OF CADMIUM SELENIDE QUANTUM DOT DISTRIBUTION USING TEMPERATURE DEPENDENT PHOTOLUMINESCENCE **, Sarah G. Martino * and Ajith DeSilva, Department of Physics, University of West Georgia, Carrollton, GA 30118. Quantum dots (QD) are nano-sized molecules with electronic semiconducting properties. This study uses Cadmium Selenide (CdSe) samples which were synthesizeds though wet chemicals exposed to UV raditation. The dynamics of excitons in CdSe QDs were studied using temperature dependent photoluminescence (PL) in the range from 17-300 K. It was shown that an asymmetric PL spectrum at 17 K causes the PL to decompose into two Gaussians. We can attribute the two bands to the existence of two spectrally resolved CdSe QD ensembles. Using TEM images of the sample, it can be seen that there is a bimodal size distribution with the average QD sizes being around 10 and 15nm. The peak energies of the QDs were 2.182 and 2.299 eV and widths of ~40 and 30 meV respectively. The PL yield of the QD sample was reasonably stable from 17K to 300K. Further, it showed that the larger QDs emit stronger at lower temperatures while the smaller QDs are stronger at higher temperatures. The authors would like to acknowledge the financial support from UWise and SRAP programs at UWG.
4:45 GENERALIZATION AND MATHEMATICAL MODEL DEVELOPMENT FOR THE MAGIC TEN CARD GAME, Sara L. Hojjatie * and Roxana A. Hojjatie *, Georgia Institute of Technology, Atlanta, GA 30332, The objective of this study is to describe a mathematical model that we have developed to generalize mathematical principle of a card game called magic ten. In this card game a deck of 52 cards is divided into two equal parts by counting 26 cards to the audience face up. The seventh card is memorized then the first part of the cards is placed at the top (both parts face down). A card from the top of the deck is placed in each of three columns (face up) then starting with the number corresponding to the first card in each column, additional cards are added to reach a maximum value of 10 in each column. After adding the numbers corresponding to the first three cards in each column, the corresponding location of a card in the deck can be predicted which is the seventh card memorized. Although the game is described by some people on the internet, however, no generalization and mathematical modeling has been developed for this interesting game. Our model indicates that the game can be expanded to play with variable number of cards (N, e.g., N = 52 for 1 deck of cards), variable number of columns (C, e.g., C = 1 to 4 for 1 deck and maximum count of 10), variable maximum count at each column (M, e.g., M = 1 to 13), and variable number of cards separated (S, e.g., S = 26) subjected to a constrain inequality of S [greater than or equal to] N-C * (M+1). The number associated with the location of the card that is memorized (P, e.g., P=7) is determined from the following equation: P = C * (1+M) - (N-S). To make the game more interesting and efficient, we suggest a modified version of the common game.
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|Publication:||Georgia Journal of Science|
|Date:||Mar 22, 2015|
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