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(1 - 4 of 4)
- Title
- DEGRADATION OF HALOGENATED ALIPHATIC COMPOUNDS IN SEQUENTIAL ANAEROBIC/AEROBIC METHANOGENIC AND HOMOACETOGENIC ENVIRONMENTS.
- Creator
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Hoxworth, Scott, Randall, Andrew, University of Central Florida
- Abstract / Description
-
The objective of this study was to utilize an alternating anaerobic/aerobic sequence to biologically transform perchloroethylene to non-hazardous end products such as ethylene, CO2 and H2 using a single microbial consortia in a methanogenic and/or a homoacetogenic environment followed by a aerobic methanotrophic environment. Reductive dechlorination of PCE and TCE to cDCE and VC in an anaerobic environment is typically carried out by methanogens, sulfidogens, or homoacetogens but often (e.g....
Show moreThe objective of this study was to utilize an alternating anaerobic/aerobic sequence to biologically transform perchloroethylene to non-hazardous end products such as ethylene, CO2 and H2 using a single microbial consortia in a methanogenic and/or a homoacetogenic environment followed by a aerobic methanotrophic environment. Reductive dechlorination of PCE and TCE to cDCE and VC in an anaerobic environment is typically carried out by methanogens, sulfidogens, or homoacetogens but often (e.g. in-situ) leads to an accumulation of daughter compounds (cDCE, VC) which are more toxic than their parent compounds (PCE, TCE). Furthermore, PCE is resistant to degradation in aerobic environments while VC and cDCE are readily oxidized co-metabolically by aerobic methanotrophic bacteria, among others. In order to achieve complete mineralization of chlorinated solvents using a biotic system, an anaerobic/aerobic treatment strategy was investigated. This strategy has been accomplished successfully at a lab scale with anaerobic and aerobic reactors in series, and in-situ anaerobic zones with downgradient aerobic zones have been proposed in the field. In contrast, the focus of this research was to expose single mixed microbial consortia to sequential anaerobic/aerobic treatments in order to determine if reductive dechlorination could be sustained following aerobic phases of treatment. If possible this would imply that the anaerobic and aerobic zones (in-situ) or reactors (ex-situ) would not necessarily have to be spatially separated. In pure or dilute cultures where soil material is not present strict anaerobes would typically not resume metabolic activity if exposed to frequent aerobic phases of treatment. However in aquifer material or reactors with large floc/granules it might be possible due to the protection of anaerobic micro-environments as a result of diffusion limitations. Microcosms contained in sealed 120-mL serum bottles were used to generate experimental data including autoclaved abiotic controls with mercuric chloride. Inocula for these microcosms come from a several sources, including anaerobic digester sludge, soils, and contaminated aquifers. Once an experimental microcosm showed signs of reductive dechlorination, an aerobic treatment was implemented. The anaerobic phase of the microcosm was interrupted with a short duration aerobic phase. Headspace air or hydrogen peroxide addition was used to supply oxygen. Analytical data from the experiments indicated that anaerobic reductive dechlorination was readily accomplished during anaerobic phase experiments as PCE was sequentially dechlorinated to TCE and then to cDCE as reported in previous research reported by others in the literature. Additionally, a few mixed consortia microcosms showed evidence of further reductive dechlorination to VC and ethylene. During the sequential environment experiments, analytical data also indicated that reductive dechlorination also resumed after an aerobic sequence utilizing hydrogen peroxide as an oxidizer in the microcosm. No conclusive evidence was observed to indicate that aerobic degradation of cDCE during any of the aerobic phase treatments. This was probably due to the inocula not containing methanotrophs.
Show less - Date Issued
- 2004
- Identifier
- CFE0000282, ucf:46238
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0000282
- Title
- Determination of Critical Rest Interval using Repeated Sprint Ability Testing.
- Creator
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Lamonica, Michael, Fukuda, David, Hoffman, Jay, Stout, Jeffrey, Fragala, Maren, University of Central Florida
- Abstract / Description
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The critical power (CP) concept has been used to determine the appropriate rest interval during intermittent exercise through the investigation of critical rest interval (CRI). Repeated sprint ability (RSA) testing has been developed to define the athlete's ability to recover and maintain maximal effort during successive bouts. The CP model has been used to understand the physiological responses involved with intermittent exercise delineating between severe and heavy exercise intensity...
Show moreThe critical power (CP) concept has been used to determine the appropriate rest interval during intermittent exercise through the investigation of critical rest interval (CRI). Repeated sprint ability (RSA) testing has been developed to define the athlete's ability to recover and maintain maximal effort during successive bouts. The CP model has been used to understand the physiological responses involved with intermittent exercise delineating between severe and heavy exercise intensity domains. The primary purpose of this study was to determine the CRI from the work-time relationship given by RSA testing using varying work to rest ratios. The secondary purpose was to determine the validity of CRI by evaluation of physiological responses above and below estimated rest interval values during intermittent cycling.Twelve recreationally trained males (mean (&)#177; SD; age 24.1 (&)#177; 3.6yr; height 175.8 (&)#177; 7.0cm; weight 77.6 (&)#177; 12.8kg; V?O2peak 43.3 (&)#177; 5.6ml/kg/min; Body Fat (%) 24.5 (&)#177; 4.4) were recruited for this study. Participants performed a graded exercise test to determine V?O2peak and peak heart rate. Eight participants completed the same three RSA protocols with 6s maximal sprints and varying rest intervals (12-24s) on a cycle ergometer. Intermittent critical power (ICP) was calculated through the linear total work (TW) and time-to-exhaustion (TTE) relationship, whereas CRI was estimated using the average work per sprint and ICP. Seven subjects completed trials above and below estimated CRI to evaluate the validity of this estimate through the examination of the physiological responses. Breath-by-breath oxygen consumption (V?O2) and heart rate (HR) values were recorded during the validation trials. One-way repeated measures analysis of variance (ANOVA) was used to analyze the variables from the RSA trials. Paired samples t-tests were performed to compare performance and physiological variables above or below CRI during the validation trials. Two-way repeated measures ANOVA was used to examined the changes in oxygen consumption (V?O2), HR, mean power (MP), and TW throughout the validation trials. Significant differences (p (<) 0.1) were found for the number of intervals completed, TTE, average work per sprint, peak and mean V?O2 between RSA protocols. Linearity between TW and TTE was r2 = 0.952 (&)#177; 0.081. During the validation trials, TTE was significantly greater in the above versus the below CRI trial (2270.43 (&)#177; 941.15s vs. 1511.00 (&)#177; 811.0s). Furthermore, blood lactate concentration (8.94 (&)#177; 4.89mmol/L vs. 6.56 (&)#177; 3.45mmol/L), AveV?O2 (2.05 (&)#177; 0.36L/min vs. 1.78 (&)#177; 0.26L/min), V?O2peak (2.84 (&)#177; 0.48L/min vs. 2.61 (&)#177; 0.43L/min), and AveHR (151.14 (&)#177; 18.46bpm vs. 138.14 (&)#177; 17.51L/min) were significantly greater in the below CRI trial when compared to the above CRI trial. Significant interactions were found between above and below trials within minimal V?O2 response (F = 6.886, p = 0.024, ?2 = 0.534) to the recovery intervals and maximal HR (F = 4.51, p = 0.016, ?2 = 0.429) response to the work intervals. During the above CRI trial, minimal V?O2 response decreased over time (51-43%V?O2 peak) while maximal HR response achieved a steady state level (81-84%HRpeak). Conversely, minimal V?O2 response during the below CRI trial achieved a steady state level (54-58%V?O2 peak), whereas maximal HR response increased over time (84-90%HRpeak).The relationship between TW and TTE is appropriate for use with RSA testing with varying rest intervals. The differing physiological response during the validation trials may reflect changes in energy system contribution. In conclusion, CRI distinguished between physiological responses related to exercise intensity domains in a manner similar to CP estimates determined from other testing and exercise modalities.
Show less - Date Issued
- 2014
- Identifier
- CFE0005645, ucf:50168
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005645
- Title
- CRITICAL VELOCITY IS ASSOCIATED WITH COMBAT SPECIFIC PERFORMANCE MEASURES IN A SPECIAL FORCES UNIT.
- Creator
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Hoffman, Mattan, Stout, Jeffrey, Fukuda, David, Fisher, Thomas, University of Central Florida
- Abstract / Description
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Over recent years, military research has focused on ways of being able to predict operational success and readiness through the development of simulated operational tasks measuring the physical limits of the soldier. Therefore, to properly prepare the tactical athlete for the demands and rigor of combat, accurate assessment of baseline physical abilities and limitations are necessary. Currently, western armies use a basic physical fitness test, which has been heavily argued to have no bearing...
Show moreOver recent years, military research has focused on ways of being able to predict operational success and readiness through the development of simulated operational tasks measuring the physical limits of the soldier. Therefore, to properly prepare the tactical athlete for the demands and rigor of combat, accurate assessment of baseline physical abilities and limitations are necessary. Currently, western armies use a basic physical fitness test, which has been heavily argued to have no bearing on operational readiness, thus they are in the process of transitioning to a more specific combat readiness test. However, specific assessments to predict operational success/readiness are inefficient or lacking. A single test that requires minimal time, but provides simultaneous assessment of the necessary physical characteristics (i.e. aerobic and anaerobic capacities) may provide a unique opportunity to enhance soldier performance assessment. The 3-min all-out run, is a relatively new test that has been recently validated. It provides two performance estimates, critical velocity (CV) and anaerobic distance capacity (ADC). CV provides a measure of the individual's aerobic capacity, while the ADC is an indicator of anaerobic capacity. The purpose of this study, therefore, is to examine the relationship between CV and ADC from the 3-min all-out run and combat specific tasks (2.5-km run, 50-m casualty carry, and repeated sprints with rush shooting) in an elite special force unit. Eighteen male soldiers (age: 19.9 (&)#177; 0.8 years; height: 177.6 (&)#177; 6.6 cm; body mass: 74.1 (&)#177; 5.8 kg; BMI: 23.52 (&)#177; 1.63) from an elite combat special force unit of the Israel Defense Forces (IDF) volunteered to complete a 3-min all-out run, while wearing a global positioning system (GPS) unit, and a battery of operational CST (2.5-km run, 50-m casualty carry and 30-m repeated sprints with (")rush(") shooting (RPTDS)). Estimates of CV and ADC from the 3-min all-out run were determined from the downloaded GPS data with CV calculated as the average velocity of the final 30 s of the run and ADC as the velocity-time integral above CV. CV exhibited significant negative correlations with the 2.5-km run time (r = - 0.62, p (<) 0.01), and RPTDS time (r = - 0.71p (<) 0.01). However, CV (r = - 0.31) or ADC (r = 0.16) did not show any correlation with the 50-m casualty carry run. In addition, CV was positively correlated with the average velocity during the 2.5- km run (r = 0.64, p (<) 0.01). Stepwise regression identified CV as the most significant performance measure associated with the 2.5-km run time, and BMI and CV measures as significant predictors of RPTDS time (R2= 0.67, p (<) 0.05). Our main findings indicate that CV was highly related to performance during CST, including the 2.5-km run and RPTDS, but not the 50-m casualty carry. Using the 3-min all-out run as a testing measurement offers a more efficient and simpler way in assessing both aerobic and anaerobic capabilities (CV and ADC) with-in a relatively large sample. In this regard, this method of testing may be conducive to a military type environment whether for selection purposes, to predict combat readiness, to prescribe a training program or just a need analysis for the company commander
Show less - Date Issued
- 2015
- Identifier
- CFE0005628, ucf:50227
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005628
- Title
- An Assessment of Biosorption Activated Media for the Removal of Pollutants in Up-Flow Stormwater Treatment Systems.
- Creator
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Hood, Andrew, Randall, Andrew, Wanielista, Martin, Chopra, Manoj, O'Reilly, Andrew, Moore, Sean, University of Central Florida
- Abstract / Description
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Nitrogen and phosphorus are often the limiting nutrients for marine and freshwater systems respectively. Additionally, stormwater often contains elevated levels of pathogens which can pollute the receiving water body and impact reuse applications [1-4]. The reduction of limiting nutrients and pathogens is a common primary target for stormwater best management practices (BMPs) [5]. Traditional BMPs, such as retention/detention treatment ponds require large footprints and may not be practical...
Show moreNitrogen and phosphorus are often the limiting nutrients for marine and freshwater systems respectively. Additionally, stormwater often contains elevated levels of pathogens which can pollute the receiving water body and impact reuse applications [1-4]. The reduction of limiting nutrients and pathogens is a common primary target for stormwater best management practices (BMPs) [5]. Traditional BMPs, such as retention/detention treatment ponds require large footprints and may not be practical in ultra-urban environments where above ground space is limited. Upflow filters utilizing biosorption activated media (BAM) that can be placed underground offer a small footprint alternative. Additionally, BAM upflow filters can be installed at the discharge point of traditional stormwater ponds to provide further treatment. This research simulated stormwater that had already been treated for solids removal; thus, most of the nutrients and solids in the influent were assumed to be as non-settable suspended solids or dissolved solids. Three different BAM mixtures in an upflow filter configuration were compared for the parameters of nitrogen, phosphorus, total coliform, E. coli, and heterotrophic plate count (HPC). Additionally, genetic testing was conducted using Polymerase Chain Reaction (PCR), in conjunction with a nitrogen mass balance, to determine if Anammox was a significant player in the nitrogen removal. The columns were run at both 22-minute and 220-minute Empty Bed Contact Times (EBCTs). All the BAM mixtures analyzed were shown to be capable at the removal of nitrogen, phosphorus, and total coliform during both the 22-minute and 220-minute EBCTs, with BAM #1 having the highest removal performance for all three parameters during both EBCTs. All BAM mixtures experienced an increase in HPC. Additionally, PCR analysis confirmed the presence of Anammox in the biofilm and via mass balance it was determined that the biological nitrogen removal was due to Anammox and endogenous denitrification with Anammox being a significant mechanism.
Show less - Date Issued
- 2019
- Identifier
- CFE0007817, ucf:52875
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007817
