Academic literature on the topic 'Reef Degradation'
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Journal articles on the topic "Reef Degradation"
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Baldock, Tom, and William Ginzo. "MORPHOLOGICAL RESPONSE OF A REEF-FRONTED BEACH TO SEA LEVEL RISE AND REEF DEGRADATION." Coastal Engineering Proceedings, no. 36v (December 28, 2020): 1. http://dx.doi.org/10.9753/icce.v36v.sediment.1.
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The morphological response of reef-fronted beaches to sea level rise and reef degradation is investigated by physical modelling. Coral barrier and fringing reefs limit the wave energy reaching sandy beaches, providing protection to many communities worldwide (Ferrario et al., 2014). Sea level rise and loss of reef flat elevation through coral mortality are expected to alter water levels over such reefs in the future. Assessing the morphological response to these processes in the field is very difficult due to the timescale involved, and lack of data for current conditions. Numerical modelling of beach profile response is also poor, even for open coast sandy beaches, and there is limited work modelling of reef fronted beaches, although hydrodynamics can be modelled reasonably well (Buckley et al., 2014). Here, new experiments on beach response to rising water levels and reducing reef flat elevation without tides are presented and compared to a conceptual model that links total sediment transport to the wave height landward of the reef (Baldock et al., 2015). A summary of recent numerical modelling of 2D planform changes for the same scenario will also be presented.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/0ya0UH1Vpsk
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Gordon, Timothy A. C., Harry R. Harding, Kathryn E. Wong, Nathan D. Merchant, Mark G. Meekan, Mark I. McCormick, Andrew N. Radford, and Stephen D. Simpson. "Habitat degradation negatively affects auditory settlement behavior of coral reef fishes." Proceedings of the National Academy of Sciences 115, no. 20 (April 30, 2018): 5193–98. http://dx.doi.org/10.1073/pnas.1719291115.
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Coral reefs are increasingly degraded by climate-induced bleaching and storm damage. Reef recovery relies on recruitment of young fishes for the replenishment of functionally important taxa. Acoustic cues guide the orientation, habitat selection, and settlement of many fishes, but these processes may be impaired if degradation alters reef soundscapes. Here, we report spatiotemporally matched evidence of soundscapes altered by degradation from recordings taken before and after recent severe damage on Australia’s Great Barrier Reef. Postdegradation soundscapes were an average of 15 dB re 1 µPa quieter and had significantly reduced acoustic complexity, richness, and rates of invertebrate snaps compared with their predegradation equivalents. We then used these matched recordings in complementary light-trap and patch-reef experiments to assess responses of wild fish larvae under natural conditions. We show that postdegradation soundscapes were 8% less attractive to presettlement larvae and resulted in 40% less settlement of juvenile fishes than predegradation soundscapes; postdegradation soundscapes were no more attractive than open-ocean sound. However, our experimental design does not allow an estimate of how much attraction and settlement to isolated postdegradation soundscapes might change compared with isolated predegradation soundscapes. Reductions in attraction and settlement were qualitatively similar across and within all trophic guilds and taxonomic groups analyzed. These patterns may lead to declines in fish populations, exacerbating degradation. Acoustic changes might therefore trigger a feedback loop that could impair reef resilience. To understand fully the recovery potential of coral reefs, we must learn to listen.
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Carvalho, Susana, Eva Aylagas, Rodrigo Villalobos, Yasser Kattan, Michael Berumen, and John K. Pearman. "Beyond the visual: using metabarcoding to characterize the hidden reef cryptobiome." Proceedings of the Royal Society B: Biological Sciences 286, no. 1896 (February 13, 2019): 20182697. http://dx.doi.org/10.1098/rspb.2018.2697.
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In an era of coral reef degradation, our knowledge of ecological patterns in reefs is biased towards large conspicuous organisms. The majority of biodiversity, however, inhabits small cryptic spaces within the framework of the reef. To assess this biodiverse community, which we term the ‘reef cryptobiome’, we deployed 87 autonomous reef monitoring structures (ARMS), on 22 reefs across 16 degrees latitude of the Red Sea. Combining ARMS with metabarcoding of the mitochondrial cytochrome oxidase I gene, we reveal a rich community, including the identification of 14 metazoan phyla within 10 416 operational taxonomic units (OTUs). While mobile and sessile subsets were similarly structured along the basin, the main environmental driver was different (particulate organic matter and sea surface temperature, respectively). Distribution patterns of OTUs showed that only 1.5% were present in all reefs, while over half were present in a single reef. On both local and regional scales, the majority of OTUs were rare. The high heterogeneity in community patterns of the reef cryptobiome has implications for reef conservation. Understanding the biodiversity patterns of this critical component of reef functioning will enable a sound knowledge of how coral reefs will respond to future anthropogenic impacts.
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Lirman, Diego, and Stephanie Schopmeyer. "Ecological solutions to reef degradation: optimizing coral reef restoration in the Caribbean and Western Atlantic." PeerJ 4 (October 20, 2016): e2597. http://dx.doi.org/10.7717/peerj.2597.
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Reef restoration activities have proliferated in response to the need to mitigate coral declines and recover lost reef structure, function, and ecosystem services. Here, we describe the recent shift from costly and complex engineering solutions to recover degraded reef structure to more economical and efficient ecological approaches that focus on recovering the living components of reef communities. We review the adoption and expansion of the coral gardening framework in the Caribbean and Western Atlantic where practitioners now grow and outplant 10,000’s of corals onto degraded reefs each year. We detail the steps for establishing a gardening program as well as long-term goals and direct and indirect benefits of this approach in our region. With a strong scientific basis, coral gardening activities now contribute significantly to reef and species recovery, provide important scientific, education, and outreach opportunities, and offer alternate livelihoods to local stakeholders. While challenges still remain, the transition from engineering to ecological solutions for reef degradation has opened the field of coral reef restoration to a wider audience poised to contribute to reef conservation and recovery in regions where coral losses and recruitment bottlenecks hinder natural recovery.
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González-Gómez, Roberto, Patricia Briones-Fourzán, Lorenzo Álvarez-Filip, and Enrique Lozano-Álvarez. "Diversity and abundance of conspicuous macrocrustaceans on coral reefs differing in level of degradation." PeerJ 6 (June 11, 2018): e4922. http://dx.doi.org/10.7717/peerj.4922.
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Coral reefs sustain abundant and diverse macrocrustaceans that perform multiple ecological roles, but coral reefs are undergoing massive degradation that may be driving changes in the species composition and abundance of reef-associated macrocrustaceans. To provide insight into this issue, we used non-destructive visual census techniques to compare the diversity and abundance of conspicuous macrocrustaceans (i.e., those >1 cm and visible without disturbance) between two shallow Caribbean coral reefs similar in size (∼1.5 km in length) and close to each other, but one (“Limones”) characterized by extensive stands of the branching coral Acropora palmata, and the other (“Bonanza”) dominated by macroalgae and relic coral skeletons and rubble (i.e., degraded). We also assessed the structural complexity of each reef and the percent cover of various benthic community components. Given the type of growth of A. palmata, we expected to find a greater structural complexity, a higher cover of live coral, and a lower cover of macroalgae on Limones, and hence a more diverse and abundant macrocrustacean community on this reef compared with Bonanza. Overall, we identified 63 macrocrustacean species (61 Decapoda and two Stomatopoda). Contrary to our expectations, structural complexity did not differ significantly between the back-reef zones of these reefs but varied more broadly on Limones, and the diversity and abundance of macrocrustaceans were higher on Bonanza than on Limones despite live coral cover being higher on Limones and macroalgal cover higher on Bonanza. However, the use of various types of microhabitats by macrocrustaceans differed substantially between reefs. On both reefs, the dominant species were the clinging crab Mithraculus coryphe and the hermit crab Calcinus tibicen, but the former was more abundant on Bonanza and the latter on Limones. M. coryphe occupied a diverse array of microhabitats but mostly coral rubble and relic skeletons, whereas C. tibicen was often, but not always, found associated with colonies of Millepora spp. A small commensal crab of A. palmata, Domecia acanthophora, was far more abundant on Limones, emerging as the main discriminant species between reefs. Our results suggest that local diversity and abundance of reef-associated macrocrustaceans are partially modulated by habitat degradation, the diversity of microhabitat types, and the establishment of different commensal associations rather than by structural complexity alone.
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Rogers, Caroline S. "Coral Reef Resilience through Biodiversity." ISRN Oceanography 2013 (February 17, 2013): 1–18. http://dx.doi.org/10.5402/2013/739034.
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Irrefutable evidence of coral reef degradation worldwide and increasing pressure from rising seawater temperatures and ocean acidification associated with climate change have led to a focus on reef resilience and a call to “manage” coral reefs for resilience. Ideally, global action to reduce emission of carbon dioxide and other greenhouse gases will be accompanied by local action. Effective management requires reduction of local stressors, identification of the characteristics of resilient reefs, and design of marine protected area networks that include potentially resilient reefs. Future research is needed on how stressors interact, on how climate change will affect corals, fish, and other reef organisms as well as overall biodiversity, and on basic ecological processes such as connectivity. Not all reef species and reefs will respond similarly to local and global stressors. Because reef-building corals and other organisms have some potential to adapt to environmental changes, coral reefs will likely persist in spite of the unprecedented combination of stressors currently affecting them. The biodiversity of coral reefs is the basis for their remarkable beauty and for the benefits they provide to society. The extraordinary complexity of these ecosystems makes it both more difficult to predict their future and more likely they will have a future.
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Chou, Loke Ming, Shu Qin Sam, Tai Chong Toh, and Chin Soon Lionel Ng. "THE RELEVANCE OF REEF RESTORATION IN THE CONTINUALLY CHANGING MARINE ENVIRONMENT OF SINGAPORE." Tạp chí Khoa học và Công nghệ Biển 18, no. 3 (November 3, 2018): 278–85. http://dx.doi.org/10.15625/1859-3097/18/3/10801.
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Singapore’s marine environment has changed significantly over the past five decades through coastal modification and intense human activities. More than 60% of its coral reefs have been lost to land reclamation and the remaining reefs remain exposed to increased sedimentation. Reef restoration to address habitat loss and degradation is considered viable under the changing environmental conditions based on the persisting annual coral mass spawning events, active recruitment, high species diversity and recovery from mass bleaching impacts. These ecological attributes indicate that reef ecosystem integrity is still functioning and restoration measures are relevant. An analysis of past and ongoing restoration initiatives indicates their effectiveness in improving degraded reefs as well as establishing new reef communities on modified coasts.
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Putra, Singgih Afifa, Indra Ambalika Syari, Helmy Akbar, Iwan Suyatna, and Davin H. E. Setiamarga. "Human activities and persistent coral reef degradation in Gaspar Strait, Bangka Belitung Islands, Indonesia." F1000Research 7 (December 20, 2018): 1962. http://dx.doi.org/10.12688/f1000research.16519.1.
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Background: The aim of the study was to describe the coral reef condition in Bangka Belitung Islands, particularly from Gaspar Strait. This research location is well known for its underwater archaeological discovery and shipwreck sites. Recent increases in mining, fishing and tourism activities in the surrounding islands might have affected the condition of the coral reef. Methods: Nine islands inside the strait were visited (i.e. Langer, Kembung, Piling, Aur, Salma, Pongok, Celagen, Kelapan, and Lepar Island), and a line transect was used to observed coral reef conditions. Results: Coral cover was found to be predominantly in fair conditions (25-50%). Coral mortality index also tended to be high, which indicated that the coral reef ecosystem was in threatened conditions. Previous and recent reports also reported the same condition as found by this study. Conclusion: Degradation of the coral community in Bangka Belitung Islands is likely caused by human activities. This suggests that increasing human activities significantly affects the coral reef condition. Protection of coral reefs with sustainable management for mining activity, tourism and fishing practices are needed.
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Wang, Yu, Jinsheng Sun, Enjun Fang, Biao Guo, Yuanyuan Dai, Yan Gao, Hong Wang, et al. "Impact of artificial reefs on sediment bacterial structure and function in Bohai Bay." Canadian Journal of Microbiology 65, no. 3 (March 2019): 191–200. http://dx.doi.org/10.1139/cjm-2018-0157.
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Artificial reefs have significantly altered ecological and environmental conditions compared with natural reefs, but how these changes affect sediment bacteria structure and function is unknown. Here, we compared the structure and function of the sediment bacterial community in the artificial reef area, the future artificial reef area, and the control area in Bohai Bay by 16S rRNA genes sequencing. Our results indicated that bacteria communities in the sediment were both taxonomically and functionally different between the reef area and control area. In the artificial reef area, the α-diversity was significantly lower, whereas the β-diversity was significantly higher. Functional genes related to chemo-heterotrophy, nitrate reduction, hydrocarbon degradation, and the human pathogens and human gut were more abundant, whereas genes related to the metabolism of sulfur compounds were less abundant in the artificial reef than in the control area. The differences in bacterial communities were primarily determined by depth in the artificial reef area, and by total organic carbon in the future reef area and control area. This study provides the first overview of molecular ecology to assess the impacts of artificial reefs on the bacteria community.
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Aronson, R. B. "Causes of Coral Reef Degradation." Science 302, no. 5650 (November 28, 2003): 1502b—1504. http://dx.doi.org/10.1126/science.302.5650.1502b.
Full textDissertations / Theses on the topic "Reef Degradation"
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Yahya, Saleh A. S. "Habitat structure, degradation and management effects on coral reef fish communities." Doctoral thesis, Stockholms universitet, Zoologiska institutionen, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-62187.
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Coral reefs are among the most diverse and productive ecosystems on earth, and are critical to the survival of tropical marine ecosystems and sustenance of local human populations. However, coral reefs are quite vulnerable to disturbances, both natural and anthropogenic. This thesis looks at how coral reef communities have responded to climactic disturbances, particularly the 1997-98 El Niño Southern Oscillation (ENSO) and subsequent coral bleaching and mortality that affected much of the Indian Ocean, including the coastal waters of Tanzania, where the study was conducted. In particular, it investigates the effects of coral bleaching, habitat degradation and reef spatial arrangement on reef fish assemblages. Habitat structural complexity and spatial arrangement of reefs had an effect on reef fish communities. Fish communities showed patterns in distribution among habitats and between patch and continuous reefs. Fishes preferred live to bleached/dead or eroded coral, but trophic groups reacted differently to patch and continuous reefs. There were slight changes in fish abundance and significant changes in fish diversity on experimental, bleached branching Acropora coral plots over a period of one year. While fish abundance on one site increased shortly after a bleaching event, 6 years later fish abundance had decreased significantly. Conversely, coral reef communities in northern Tanzania had changed little over an 8-year period, with minor changes associated with the 1997-98 ENSO and the presence or absence of fisheries management. The coral reefs in the region were found to show high variability in community structure and responses of associated fish and invertebrate communities. The findings of this thesis indicate the importance of habitat structure and spatial arrangement of reefs, the detrimental effects of coral bleaching, and the possibility that some reefs and some (generalist) reef fish taxa may exhibit resilience to climate change.At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.
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Eilers, Reef Janes [Verfasser], Wolfgang [Akademischer Betreuer] Nebel, and Steffen [Akademischer Betreuer] Paul. "Abstraction of aging models for high level degradation prediction / Reef Janes Eilers ; Wolfgang Nebel, Steffen Paul." Oldenburg : BIS der Universität Oldenburg, 2017. http://d-nb.info/1137322969/34.
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Eilers, Reef Janes Verfasser], Wolfgang [Akademischer Betreuer] [Nebel, and Steffen [Akademischer Betreuer] Paul. "Abstraction of aging models for high level degradation prediction / Reef Janes Eilers ; Wolfgang Nebel, Steffen Paul." Oldenburg : BIS der Universität Oldenburg, 2017. http://nbn-resolving.de/urn:nbn:de:gbv:715-oops-32935.
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Paredes, Gustavo Adolfo. "Degradation and recovery of Caribbean coral reefs." Diss., [La Jolla, Calif.] : University of California, San Diego, 2009. http://wwwlib.umi.com/cr/ucsd/fullcit?p3356249.
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Thesis (Ph. D.)--University of California, San Diego, 2009.Title from first page of PDF file (viewed July 7, 2009). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.
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Alvarez, Filip Lorenzo. "Habitat complexity in coral reefs : patterns of degradation and consequences for biodiversity." Thesis, University of East Anglia, 2010. https://ueaeprints.uea.ac.uk/19102/.
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Ojoghoro, Jasper Oreva. "Biodegradation of the steroid progesterone in surface waters." Thesis, Brunel University, 2017. http://bura.brunel.ac.uk/handle/2438/16120.
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Many studies measuring the occurrence of pharmaceuticals, understanding their environmental fate and the risk they pose to surface water resources have been published. However, very little is known about the relevant transformation products which result from the wide range of biotic and abiotic degradation processes that these compounds undergo in sewers, storage tanks, during engineered treatment and in the environment. Thus, the present study primarily investigated the degradation of the steroid progesterone (P4) in natural systems (rivers), with a focus on the identification and characterisation of transformation products. Initial work focussed on assessing the removal of selected compounds (Diclofenac, Fluoxetine, Propranolol and P4) from reed beds, with identification of transformation products in a field site being attempted. However, it was determined that concentrations of parent compounds and products would be too low to work with in the field, and a laboratory study was designed which focussed on P4. Focus on P4 was based on literature evidence of its rapid biodegradability relative to the other model compounds and its usage patterns globally. River water sampling for the laboratory-based degradation study was carried out at 1 km downstream of four south east England sewage works (Blackbirds, Chesham, High Wycombe and Maple Lodge) effluent discharge points. Suspected P4 transformation products were initially identified from predictions by the EAWAG Biocatalysis Biodegradation Database (EAWAG BBD) and from a literature review. At a later stage of the present work, a replacement model for EAWAG BBD (enviPath) which became available, was used to predict P4 degradation and results were compared. Samples were analysed using low resolution and accurate-mass time-of-flight mass spectrometers. Three degradation studies were conducted. Sampling for all studies was carried out at the same time in the year to minimize temporal variability in conditions and allow for effective comparison of results. Androgenic and progesterone yeast screens were carried out to assess the biological activity of transformation products.
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Hoxworth, Scott. "DEGRADATION OF HALOGENATED ALIPHATIC COMPOUNDS IN SEQUENTIAL ANAEROBIC." Master's thesis, University of Central Florida, 2004. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2803.
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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. 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.M.S.Env.E.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Environmental Engineering
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Leyte-Vidal, Albert. "ESTABLISHING DEGRADATION RATES AND SERVICE LIFETIME OF PHOTOVOLTAIC SYSTEMS." Master's thesis, University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3001.
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As fossil fuel sources continue to diminish, oil prices continue to increase, and global warming and CO2 emissions keep impacting the environment, it has been necessary to shift energy consumption and generation to a different path. Solar energy has proven to be one of the most promising sources of renewable energy because it is environmentally friendly, available anywhere in the world, and cost competitive. For photovoltaic (PV) system engineers, designing a PV system is not an easy task. Research demonstrates that different PV technologies behave differently under certain conditions; therefore energy production varies not only with capacity of the system but also with the type of module. For years, researchers have also studied how these different technologies perform for long periods of time, when exposed out in the field. In this study, data collected by the Florida Solar Energy Center for periods of over four years was analyzed using two techniques, widely accepted by researchers and industry, to evaluate the long‐term performance of five systems. The performance ratio analysis normalizes system capacity and enables the comparison of performance between multiple systems. In PVUSA Regression analysis, regression coefficients are calculated which correspond to the effect of irradiance, wind speed, and ambient temperature, and these coefficients are then used to calculate power at a predetermined set of conditions. This study allows manufacturers to address the difficulties found on system lifetime when their modules are installed out on the field. Also allows for the further development and improvement of the different PV technologies already commercially available.M.S.
School of Electrical Engineering and Computer Science
Engineering and Computer Science
Electrical Engineering MSEE
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Hadagali, Vinaykumar. "HIGH VOLTAGE BIAS TESTING AND DEGRADATION ANALYSIS OF PHOTOVOLTAIC MODULES." Master's thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3207.
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This thesis mainly focuses on two important aspects of the photovoltaic modules. The first aspect addressed the high voltage bias testing and data and degradation analysis of high voltage biased thin film photovoltaic modules. The second aspect addressed the issues of reliability and durability of crystalline silicon module. Grid-connected photovoltaic systems must withstand high voltage bias in addition to harsh environmental conditions such as intermittent solar irradiance, high humidity, heat and wind. a-Si:H thin-film photovoltaic modules with earlier generation SnO2:F transparent conducting oxide (TCO) on the front glass installed on the FSEC High Voltage Test Bed were monitored since December 2001. The data was collected on a daily basis and analyzed. The leakage currents for some chosen time period were calculated and compared with the measured values. Current-voltage characteristic measurements were carried out to check any reduction in the power. Samples were cored and extracted for analysis from one of the -600 V biased modules. Leakage currents in high-voltage-biased laminates specially prepared with improved SnO2:F TCO are being monitored in the hot and humid climate in Florida. Negatively-biased modules showed clear signs of delamination. The leakage currents in high-voltage biased photovoltaic modules are functions of both temperature and relative humidity. Photovoltaic module leakage conductance was found to be thermally stimulated with a characteristic activation energy that depends on relative humidity. The adhesional strength was lost completely in the damaged area. Leakage current values from support to ground in new, unframed laminates fabricated with improved SnO2:F TCO layer were ~100 times lower under the high voltage bias in hot and humid environment. Information on the failure of field deployed modules must be complemented with why and how the modules fail while considering the issues of reliability and durability of crystalline silicon module. At present, all the failure modes have not been identified and failure mechanisms have not been understood. Experience has shown that as the materials and processes are changed, reliability issues that apparently had been resolved resurface. A multicrystalline silicon photovoltaic module that was manufactured by a non-US company and that had shown >50% performance loss in field-deployment of <2 years in hot and dry climate were studied for degradation analysis in comparison with a mc-Si module that was manufactured by the same company and that performed well after 10 years of field-deployment in hot and humid climate.. I-V measurements were carried out to analyze the reduction in photovoltaic parameters. Solder bond strength in mc-Si photovoltaic modules were measured to understand early degradation of performance. Samples were cored and extracted for further analysis. Adhesional strength between the busline metallization and the silicon cell in a newer generation mc-Si photovoltaic module was found to be considerably lower than that in the earlier vintage module. These results can be useful for early detection and diagnosis of field reliability issues and could assist in establishing correlation between long-term field data and observations and accelerated environmental stress testing. It is suggested that more detailed study should be undertaken using unencapsulated strings of crystalline silicon modules so as to avoid complication due to encapsulant creeping beneath the ribbons.M.S.M.S.E.
Department of Mechanical, Materials and Aerospace Engineering;
Engineering and Computer Science
Materials Science and Engineering
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Zhuge, Jinfeng. "Fire Retardant Polymer Nanocomposites: Materials Design and Thermal Degradation Modeling." Doctoral diss., University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5591.
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Compared to conventional materials, polymer matrix composites (PMCs) have a number of attractive properties, including light weight, easiness of installation, potential to lower system-level cost, high overall durability, and less susceptibility to environmental deterioration. However, PMCs are vulnerable to fire such that they degrade, decompose, and sometimes yield toxic gases at high temperature. The degradation and decomposition of composites lead to loss in mass, resulting in loss in mechanical strength. This research aims to improve the structural integrity of the PMCs under fire conditions by designing and optimizing a fire retardant nanopaper coating, and to fundamentally understand the thermal response and post-fire mechanical behavior the PMCs through numerical modeling. Specifically, a novel paper-making process that combined carbon nanofiber, nanoclay, exfoliated graphite nanoplatelet, and ammonium polyphosphate into a self-standing nanopaper was developed. The nanopaper was then coated onto the surface of the PMCs to improve the fire retardant performance of the material. The morphology, thermal stability, flammability, and post-fire flexural modulus of the nanopaper coated-PMCs were characterized. The fire retardant mechanism of the nanopaper coating was studied. Upon successfully improving the structure integrity of the PMCs by the nanopaper coatings, a thermal degradation model that captured the decomposition reaction of the polymer matrix with a second kind boundary condition (constant heat flux) was solved using Finite Element (FE) method. The weak form of the model was constructed by the weighted residual method. The model quantified the thermal and post-fire flexural responses of the composites subject to continuously applied heat fluxes. A temperature dependent post-fire residual modulus was assigned to each element in the FE domain. The bulk residual modulus was computed by assembling the modulus of each element. Based on the FE model, a refined Finite Difference (FD) model was developed to predict the fire response of the PMCs coated with the nanopapers. The FD model adopted the same post-fire mechanical evaluation method. However, unlike the FE model, the flow of the decomposed gas, and permeability and porosity of the composites were taken into account in the refined FD model. The numerical analysis indicated that the thickness and porosity of the composites had a profound impact on the thermal response of the composites. The research funding from the Office of Naval Research (ONR) and Federal Aviation Administration Center of Excellence for Commercial Space Transportation (FAA COE AST) is acknowledged.ID: 031001281; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Adviser: Jihua Gou.; Title from PDF title page (viewed February 26, 2013).; Thesis (Ph.D.)--University of Central Florida, 2012.; Includes bibliographical references (p. 179-198).
Ph.D.
Doctorate
Mechanical and Aerospace Engineering
Engineering and Computer Science
Mechanical Engineering
Books on the topic "Reef Degradation"
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Cesar, Herman. The economics of worldwide coral reef degradation. Arhem, Netherlands: CEEC, 2003.
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Wistara, Nyoman Jaya. Inovasi metodologi dan metode estimasi cadangan karbon dalam hutan dalam rangka program reduced emissions from deforestation and degradation (REED) Indonesia: Laporan hasil penelitian tahun kedua hibah kompetitif penelitian strategis nasional. Bogor]: Lembaga Penelitian dan Pengabdian Kepada Masyarakat, Institut Pertanian Bogor, 2010.
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O, Lindén, and Coral Reef Degradation in the Indian Ocean Programme., eds. Coral Reef Degradation in the Indian Ocean: Status report 2002. Colombo: CORDIO, 2002.
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Sheppard, Charles R. C., Simon K. Davy, Graham M. Pilling, and Nicholas A. J. Graham. Reef fish. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198787341.003.0006.
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This chapter discusses factors that have led to reef fish diversity. Geographic drivers for fish diversity, ranging from global historical events to local-scale drivers, are examined. Age and growth in reef fish are explored, followed by larval fish ecology. Colour diversity in modern reef fish is examined, along with mechanisms that have developed to enhance feeding success or predation avoidance. Different ecological feeding niches of coral reef fish are described and examples are given to illustrate the wide range of feeding mechanisms. The science around the abundance, biomass and trophic interactions of reef fish assemblages is examined. The range of fish feeding habits is detailed and functional roles of fish explored. Finally, the implications of changes in the reef fish community through fishing and habitat degradation are examined, highlighting the cascade effect of impacts on reefs, and how the influences of different disturbances interact to influence coral reef fish.
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Sheppard, Charles. 9. Doing something about it. Oxford University Press, 2014. http://dx.doi.org/10.1093/actrade/9780199682775.003.0009.
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A quarter of the world’s reef system is already dead, and a further half is affected to varying degrees. ‘Doing something about it’ proposes two groups of measures to address this situation. First, the overall human impact on reefs, such as fishing intensity and pollution, needs to be managed. Second, some protected marine areas need to be demarcated, instead of all areas being used in sourcing food in haphazard and decreasingly effective ways. This would mirror systems already in place on land. The continued rise in the worldwide human population has put additional pressure on the reefs as a place to procure food. This means that reef degradation is no longer a just a scientific problem, but is now also a political and social one.
Book chapters on the topic "Reef Degradation"
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McFarland, Brian Joseph. "The Context of Coral Reef Degradation and Loss." In Conservation of Tropical Coral Reefs, 5–62. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-57012-5_2.
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Salvat, Bernard. "Health and Degradation of Coral Reefs: Assessment and Future." In Marine Productivity: Perturbations and Resilience of Socio-ecosystems, 343–54. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-13878-7_38.
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Sheppard, Charles. "6. Reef fish and other major predators." In Coral Reefs: A Very Short Introduction, 68–84. Oxford University Press, 2021. http://dx.doi.org/10.1093/actrade/9780198869825.003.0006.
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Fish, like corals, have geographical patterns across regions and across individual reefs, being structured in the latter case by wave energy and depth. The thousands of species show a variety of feeding patterns. Detritus feeders are very abundant, feeding on the detritus on the seabed, especially in the fine, filamentous algal turf on apparently bare rock. Plankton feeders are common also, and herbivorous fishes show a large abundance, perhaps a quarter of the total species present, cropping algae that otherwise would grow unchecked and smother coral. Since turf algae also contain many micro-species and detritus, most herbivores also ingest much food other than simple plant material. Carnivores range from extreme specialists, such as polyp-picking butterflyfish, to generalists. Sharks and barracuda only consume other fish and generally are at the top of their food chains. The complicated ecological structure of the food webs can be clarified by analysing nitrogen isotope ratios in their tissues. Other important coral carnivores include the crown of thorns starfish, which can remove almost all living coral on a reef when it develops into plagues. Overfishing by humans greatly disturbs the equilibrium of a reef, and this is increasingly causing reef degradation.
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Sheppard, Charles. "7. Regional scale pressures on reefs." In Coral Reefs: A Very Short Introduction, 85–101. Oxford University Press, 2021. http://dx.doi.org/10.1093/actrade/9780198869825.003.0007.
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One consequence of the extremely high biodiversity found on reefs is the enormous number of interlocking connections between components. But connections can be destroyed by many kinds of stressors such as pollutants, as can the species themselves. Some species or processes have high redundancy—if destroyed others can fill their role on a reef—while other species or processes may be more or less irreplaceable, in which case when they are destroyed key processes maintaining a healthy reef can be destroyed too. Because so many countries and human communities are dependent on reefs, reef degradation, which is now occurring on a very worrying scale, is of increasing concern. Impacts fall into two main categories: those caused by numerous, usually localized, impacts, such as different forms of pollution and shoreline developments that create large quantities of sediment; and those caused by the more recently recognized, and probably more serious, long-term factors associated with climate change. All of these are ultimately interlinked and all are caused by human activities. Many occur concurrently, each exacerbating the harmful effects of others, and many are synergistic in their impacts. Sewage, nutrient run-off, landfill, dredging, and sedimentation are most important, as are chemicals, pesticides, and metals. Coral diseases are increasing also, commonly as a result. In many areas now too overfishing has become critical and may be the most ecosystem-distorting factor of all.
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"Marine Artificial Reef Research and Development: Integrating Fisheries Management Objectives." In Marine Artificial Reef Research and Development: Integrating Fisheries Management Objectives, edited by Oscar Delgadillo-G and Nirith N. Toro. American Fisheries Society, 2018. http://dx.doi.org/10.47886/9781934874516.ch13.
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<em>Abstract</em>.—Multiple coastal development activities coupled with unsustainable management have caused environmental degradation in the Santa Marta region of Colombia. To mitigate this impact, Ecopetrol entered into alliances with private and government institutions to initiate an integrative artificial reef project in Pozos Colorados Bay. To develop the project’s framework, it was necessary to (1) establish context and objectives, (2) design plans and reef construction, (3) strengthen a target social population, and (4) conduct pre- and postdeployment ecological assessments. The achievement of each objective was met with delays and constraints, mainly due to administrative issues and legal requirements. Nevertheless, interventions and interactions among representatives of the 10 institutions involved in the project, as well as the strong commitment of fishers from three organizations in all stages of the process, were indicators of project’s success. Together, these actions and contributions resulted in the deployment of the first six artificial reefs in a 137-ha area. Moreover, recorded changes in biological assemblages before and after reef deployment (richness: 3–37 species; abundance: 30.3–1,615.7 individuals), along with the presence of commercial, ecological, and endangered important species, support the concept of habitat enhancement procedures used here as a strategy for biodiversity conservation with potential for ecotourism activities. The utilization of this technology should be conducted in compliance with concerted schemes for coastal resource management and precautionary principles, directed towards the conformation of discrete marine reserves as future models of sustainable production in sensitive areas.
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"Modelling and Visualising Interactions between Natural Disturbances and Eutrophication as Causes of Coral Reef Degradation." In Oceanographic Processes of Coral Reefs, 133–46. CRC Press, 2000. http://dx.doi.org/10.1201/9781420041675-13.
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Spagnol, Simon, Eric Wolanski, and Laurence McCook. "Modelling and Visualizing Interactions between Natural Disturbances and Eutrophication as Causes of Coral Reef Degradation." In Oceanographic Processes of Coral Reefs, 113–25. CRC Press, 2000. http://dx.doi.org/10.1201/9781420041675.ch8.
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"Life in the Slow Lane: Ecology and Conservation of Long-Lived Marine Animals." In Life in the Slow Lane: Ecology and Conservation of Long-Lived Marine Animals, edited by Felicia C. Coleman, Christopher C. Koenig, Anne-Marie Eklund, and Churchill B. Grimes. American Fisheries Society, 1999. http://dx.doi.org/10.47886/9781888569155.ch18.
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<em>Abstract.</em> —Effective fisheries management requires considerable information on life history characteristics, recruitment dynamics, habitat requirements, and fishery interactions for the managed species. It is clear that we have little of this information for any of the myriad temperate reef fishes managed in the South Atlantic or Gulf of Mexico regions, not only from our reliance on size limits, controlled effort, or limited harvest but from the repeated failures of all but complete closures of fisheries to allow recovery from overexploitation. Several of the life history features that reef fish share render them particularly vulnerable to both fishing pressure and habitat degradation, including their longevity, their slow maturation, their spatially and temporally predictable spawning aggregations, and the reliance of juveniles on estuarine nursery grounds. In addition, traditional hindcasting methods like virtual population analysis and the use of spawningpotential ratio to diagnose overfishing have not proved reliable means of assessing population status. Virtually unexplored in the United States to date are (1) use of marine fishery reserves to protect demographics and reproductive potential of exploited species, habitat and community structure of all species, and biodiversity and (2) use of forecasting methods of stock assessment based on juvenile abundances. We discuss the ability of these methods to provide insurance against management error and to predict fishery abundances for future year classes, respectively.
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Braverman, Irus. "Building Bridges and Trees." In Coral Whisperers, 139–51. University of California Press, 2018. http://dx.doi.org/10.1525/california/9780520298842.003.0008.
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Ken Nedimyer is founder and president of the Coral Restoration Foundation. He has lived and worked in the Florida Keys for over forty years and has witnessed firsthand the degradation of the Florida Reef Tract. He established one of the largest coral nurseries in the world and has been training restoration groups, especially in the Caribbean, on how to use his unique coral tree technique. Nedimyer won multiple awards, including a CNN Hero in 2012 and a Disney Conservation Hero in 2014. I first interviewed him over the phone on January 4, 2016, then met him in person in Hawai‘i, and finally interviewed him a couple of weeks after Hurricane Irma hit the Florida Keys. Nedimyer is the only nonscientist among the interchapter interviews. His narrative is important, in my view, precisely because he is an outsider to that world, therefore providing a fresh reflection on both scientists and the existing legal regimes....
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"Mangroves as Fish Habitat." In Mangroves as Fish Habitat, edited by Aaron J. Adams and Karen J. Murchie. American Fisheries Society, 2015. http://dx.doi.org/10.47886/9781934874424.ch3.
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<em>Abstract</em>.—Mangrove habitats are among the most threatened coastal habitats. Loss and degradation of mangroves have broad impacts because mangroves are important in prevention of coastal erosion, are excellent at carbon sequestration, and are critical habitats for many marine and estuarine fishes, including coral reef species. However, these species often lack the economic importance or charismatic characteristics to leverage conservation of mangrove habitats. Recent and ongoing research is demonstrating the importance of mangrove habitats to economically important recreational fish species that, in conjunction with reports on the economic impact of these fisheries, provides leverage for mangrove conservation. Two recreational fish species—Common Snook <em>Centropomus undecimalis </em>and Tarpon <em>Megalops atlanticus</em>—depend on mangrove habitats for one or more of their life stages. Two other species— Bonefish <em>Albula vulpes </em>and Barramundi <em>Lates calcarifer</em>—are concurrent with mangroves. Each species supports fisheries with annual economic impacts of hundreds of millions of dollars and a large constituency of users. The combination of biological and economic research on these and other recreational fish species can be used as tools for mangrove conservation, adding a much needed boost to coastal conservation efforts and providing protection to many ecologically important but less charismatic species.
Conference papers on the topic "Reef Degradation"
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Zhao, Yinlin, Hongjie Wen, Bing Ren, Guoyu Wang, and Yongxue Wang. "An Improved SPH Model for Simulating Hydrodynamic Consequences Induced by Reef Degradation." In ASME 2020 39th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/omae2020-18520.
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Abstract Coral reefs degradation accelerates in recent decades due to the natural disturbance and anthropogenic activities. It is important to predict and evaluate reasonably the hydrodynamic consequences of reef degradation. An improved weakly compressible smoothed particle hydrodynamic (WCSPH) porous model is developed based on the standard two-phase mixture theory. The developed WCSPH mixture model is validated by comparing the predicted results with the corresponding available data. The model is then adopted to predict the effects of reef degradation on the spatial distributions of wave setup, wave-induced current and low frequency wave energy over the reef-flat under the reef resonance conditions.
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Lutaenko, Konstantin, and Konstantin Lutaenko. "COASTAL MARINE BIODIVERSITY OF VIETNAM: CURRENT PROBLEM." In Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.21610/conferencearticle_58b43159228ea.
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A brief overview of the coastal biodiversity of Vietnam based on surveys conducted by the A.V. Zhirmunsky Institute of Marine Biology, Far Eastern Branch of the Russian Academy of Sciences for last 35 years. Main problems related to threats to biodiversity are discussed on the example of the intertidal communities, coral reefs, and molluscan diversity. Threats to marine biodiversity in Vietnam are summarized as follows: habitat degradation, fragmentation and loss (especially important are mangrove forest destruction, loss of coral reefs, change in landscape mosaic of wetland, estuary, sand and mud flats); global climate change including sea level rise, storm events, rainfall pattern change, warming of the coastal ocean; effects of fishing and other forms of overexploitation; pollution and marine litter; species introduction/invasions; physical alterations of coasts; tourism. Consolidated data of Vietnamese and Russian researchers on biodiversity and coastal zone management can be used in interpretations of ecosystem changes and for development of recommendations for local/national decision-makers.
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Lutaenko, Konstantin, and Konstantin Lutaenko. "COASTAL MARINE BIODIVERSITY OF VIETNAM: CURRENT PROBLEM." In Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.31519/conferencearticle_5b1b9371a04467.54905418.
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A brief overview of the coastal biodiversity of Vietnam based on surveys conducted by the A.V. Zhirmunsky Institute of Marine Biology, Far Eastern Branch of the Russian Academy of Sciences for last 35 years. Main problems related to threats to biodiversity are discussed on the example of the intertidal communities, coral reefs, and molluscan diversity. Threats to marine biodiversity in Vietnam are summarized as follows: habitat degradation, fragmentation and loss (especially important are mangrove forest destruction, loss of coral reefs, change in landscape mosaic of wetland, estuary, sand and mud flats); global climate change including sea level rise, storm events, rainfall pattern change, warming of the coastal ocean; effects of fishing and other forms of overexploitation; pollution and marine litter; species introduction/invasions; physical alterations of coasts; tourism. Consolidated data of Vietnamese and Russian researchers on biodiversity and coastal zone management can be used in interpretations of ecosystem changes and for development of recommendations for local/national decision-makers.
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Sunyowati, Dina, and Annisa Firdhausy. "Marine Environment and Climate Change : Legal Aspects of Protection and Prevention Against Coral Reefs Degradation in Indonesia." In 1st International Conference Postgraduate School Universitas Airlangga : "Implementation of Climate Change Agreement to Meet Sustainable Development Goals" (ICPSUAS 2017). Paris, France: Atlantis Press, 2018. http://dx.doi.org/10.2991/icpsuas-17.2018.55.
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Wan, Qiaoqiao, Eunhye Cho, Seungman Park, Bumsoo Han, Hiroki Yokota, and Sungsoo Na. "Visualizing Chondrocyte Mechanotransduction in 3D." In ASME 2013 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/sbc2013-14484.
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Chondrocytes are the only cell type present in the articular cartilage and their response to mechanical stimuli influences the maintenance and remodeling of the cartilage. Numerous studies have shown that the balance between anabolic and catabolic responses of the chondrocytes to mechanical loading is dependent on the loading intensities (reviewed in ref. [1]). Moderate, physiological loading, for instance, increases synthetic activity of the extracellular matrix (ECM) such as collagen type II, aggrecan, and proteoglycan, while decreasing the catabolic activity of degradative enzymes such as matrix metalloproteinases (MMPs) and ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs) [2,3]. In contrast to moderate loading, static or high-intensity loading has been shown to degrade the cartilage resulting from inhibition of matrix synthesis and up-regulation of catabolic activities [3,4]. Therefore, the importance of these load-dependent signaling pathways involved in the maintenance and remodeling of the cartilage is widely accepted. However, the underlying mechanisms as to how varying magnitudes of mechanical stimuli trigger differential signaling activities that consequently lead to selective gene expression are not clear. FAK and Src are considered to be the main mechanotransduction signaling proteins at the cell-ECM adhesion sites and their activities influence various structural and signaling changes within the cell, including cytoskeletal organization, migration, proliferation, differentiation, and survival [5]. Accumulating evidence has shown that Src and FAK play crucial roles in regulating cartilage maintenance and degeneration and their activation stimulates matrix catabolic genes and activity [6,7]. Rho family GTPases such as RhoA and Rac1 play critical roles in fundamental processes including morphogenesis, polarity, movement, and cell division [8]. They also contribute to cartilage development and degradation [9,10]. Despite these studies, much remains to be elucidated on how load-induced Src and FAK participate in chondrocyte functions, and how their interactions are linked and regulated in connection to the activities of RhoA and Rac1 under different loading conditions. In this study, we use fluorescence resonance energy transfer (FRET)-based biosensors to monitor activities of Src and FAK as well as individual GTPases and evaluate the potential linkage of a network of these signaling molecules under different loading conditions.
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VanderSchee, David A. "Field Performance and Surge Testing of Centrifugal Compressors." In 1998 2nd International Pipeline Conference. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/ipc1998-2126.
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In 1997 Alberta Natural Gas Co. Ltd (ANG) completed a field testing program of its centrifugal compressor fleet. Field performance and surge testing of centrifugal compressors in pipeline service was done for efficiency evaluation and to re-establish surge line control. By confirming the actual location of the surge line, surge controllers are adjusted to allow a more efficient and greater operating range resulting in fuel savings and operating flexibility. The results of this testing provides an accurate operating window for the compression equipment which is then transferred to a hydraulic analysis computer model used to provide accurate capacity estimates in support of additional gas transmission contractible volumes. As part of the surge testing, suction to impeller eye differential pressure readings (used for surge control) were evaluated to determine strength, stability and repeatability. Finally, baseline data was established to determine current compressor operating efficiencies and will be used to determine future efficiency degradation. ANG is a wholly owned subsidiary of TransCanada PipeLines, one of North America’s leading transporters of natural gas through its energy transmission businesses. ANG owns and operates the British Columbia segment of the Alberta-California pipeline system (ref Figure 1). Compression is provided at three compressor stations with eleven compressors totalling 187,000 installed ISO HP.
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Biagiotti, Stephen F., Eric Houston, George Licina, and Dilip Dedhia. "Improving the Value of Excavations Through Indirect Inspection and Engineering Assessments." In ASME 2012 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/pvp2012-78543.
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U.S. nuclear power plants are implementing a life cycle management approach to underground and buried pipe integrity management. The last few years have been spent gathering information about these systems and performing relative risk ranking analyses. The next stage of this process was to further refine the risk prioritization by gathering additional indirect performance information to qualitatively characterize the effectiveness of existing corrosion control measures, thereby refining the prioritization of locations with highest potential for corrosion activity. Once these locations are better understood, strategic quantitative Direct Examination techniques (i.e., NDE) can be used to inspect and then evaluate the fitness for service and remaining life. This paper provides a brief review of the increased interest in performing excavations at nuclear sites and will present corrosion engineering techniques that uniquely evaluate both the internal and external corrosion threats using ACCORDION© and APEC©, as well as an overall strategy designed to help maximize the value of each excavation. Application of the systematic methodology presented as part of a NEI 09-14 Reasonable Assurance process [Ref 1] can increase a site’s likelihood for the proactive detection of corrosion degradation — which is a key objective for the assurance of structural and/or leakage integrity of buried piping.
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Hsu, L. L. "Total Corrosion Control for Industrial Gas Turbines: Airborne Contaminants and Their Impact on Air/Fuel/Water Management." In ASME 1988 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1988. http://dx.doi.org/10.1115/88-gt-65.
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Turbine longevity in the field is determined by the extent of its operation within design limits under mechanical and thermal loads as well as the environmental effects that undermine material properties on component surfaces. It is standard practice for the original equipment manufacturer (OEM) to specify maximum concentrations of harmful contaminants in the fuel for corrosion control. Some manufacturers have deployed on-line, in-service monitoring systems designed to incorporate data, such as temperature, speeds and start-stop cycles, into a functional, quasi-empirical equation, with an environmental factor, to continuously assess the condition of the turbine package for maintenance and overhaul purposes. This environmental factor simply categorizes fuel types in some generic correlation of fuel with hot section degradation. This paper discusses the concept of air, fuel and water management, an approach that has evolved at the author’s Company as a focused and cost-effective means of assessing the total turbomachinery environment. The ultimate objective is to employ the methodology described above for hot section corrosion life prediction and optimized maintenance planning with minimal capitalization and operating costs for maximum economic payback. The fundamental principle of this approach is represented schematically in Fig. 1 and discussed in more detail in Ref. 1. For total corrosion control, the engine environment is the sum of all contaminants present in the air, fuel and water (or steam). Tradeoffs in fluid quality can be tolerated provided the combined total concentration of a critical contaminant does not exceed the maximum allowable limits. Instead of separate restrictions on air, fuel and water quality, combined limits on total concentrations should be defined which then allows each fluid to vary in quality, thus providing greater flexibility for accommodating customer requirements or site specific conditions.
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Haraldsen, Kristian. "Unique Long Term Simulated Service Testing of Selected Deep Water Wet Insulation Coating Systems." In ASME 2013 32nd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/omae2013-10630.
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The oil and gas industry is moving to deeper water developments and thermal insulation of pipelines at 2–3000 meter water depths is required. Wet thermal insulation systems are exposed directly to the seawater and large hydrostatic water pressure in combination with high fluid temperatures challenge the integrity of the insulation systems. The thermal insulation properties of the insulation system can be gradually decreased by thermal and physical strains and challenge the flow assurance if not taken into account in the design. Wet thermal insulation systems have traditionally been qualified for long term use by a combination of long-term small scale aging tests and shorter term full scale simulated service tests (typically 7–28 days). To evaluate the long performance, simulated service tests have been run for one full year at high water pressure and internal pipe temperatures. A selection of commercially available wet insulation systems have been tested together with system specific field joint coatings under the maximum internal pipe temperature specified for the individual coating systems. The test has been run in natural seawater at 300 barg pressure and temperature of 2–4 °C. The coating thicknesses have been selected to give U-values of 3–4 W/(m2K). Before the simulated service testing all test pipes were run through a simulated reel installation to impose realistic strains on the coating systems before testing. All tested coatings performed according to expectations during the simulated service test. The syntactic systems (PP and PU based) gave gradual decrease in thermal insulation efficiency with time but the reduction was close to linear and can be accounted for in the design. The coating systems based on solid polymer materials did not show the same reduction of thermal insulation properties with time. Tests of natural cool-down performance of the insulated test pipes showed that the cool down times were maintained during the one year simulated service tests. Post-test investigations of the insulation materials did not reveal significant degradation of the materials as result of the tests but coating systems application related defects were identified which had developed over the test period. None of the pre-existing defects developed to such an extent as to affect the overall U-value of the coating system.
Reports on the topic "Reef Degradation"
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Ruiz de Gauna, Itziar, Anil Markandya, Laura Onofri, Francisco (Patxi) Greño, Javier Warman, Norma Arce, Alejandra Navarrete, et al. Economic Valuation of the Ecosystem Services of the Mesoamerican Reef, and the Allocation and Distribution of these Values. Inter-American Development Bank, May 2021. http://dx.doi.org/10.18235/0003289.
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Coral reefs are one of the most diverse and valuable ecosystems on Earth. The Mesoamerican Reef contains the largest barrier reef in the Western Hemisphere. However, its health is threatened, so there is a need for a management and sustainable conservation. Key to this is knowing the economic value of the ecosystem. “Mainstreaming the value of natural capital into policy decision-making is vital” The value of environmental and natural resources reflects what society is willing to pay for a good or service or to conserve natural resources. Conventional economic approaches tended to view value only in terms of the willingness to pay for raw materials and physical products generated for human production and consumption (e.g. fish, mining materials, pharmaceutical products, etc.). As recognition of the potential negative impacts of human activity on the environment became more widespread, economists began to understand that people might also be willing to pay for other reasons beyond the own current use of the service (e.g. to protect coral reefs from degradation or to know that coral reefs will remain intact in the future). As a result of this debate, Total Economic Value (TEV) became the most widely used and commonly accepted framework for classifying economic benefits of ecosystems and for trying to integrate them into decision-making. This report estimates the economic value of the following goods and services provided by the MAR's coral reefs: Tourism & Recreation, Fisheries, Shoreline protection. To our knowledge, the inclusion of non-use values in the economic valuation of the Mesoamerican Barrier Reef System is novel, which makes the study more comprehensive.