935 resultados para Small Scale Municipally
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Thesis (Master's)--University of Washington, 2016-06
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This paper is the second in a series of studies working towards constructing a realistic, evolving, non-potential coronal model for the solar magnetic carpet. In the present study, the interaction of two magnetic elements is considered. Our objectives are to study magnetic energy build-up, storage and dissipation as a result of emergence, cancellation, and flyby of these magnetic elements. In the future these interactions will be the basic building blocks of more complicated simulations involving hundreds of elements. Each interaction is simulated in the presence of an overlying uniform magnetic field, which lies at various orientations with respect to the evolving magnetic elements. For these three small-scale interactions, the free energy stored in the field at the end of the simulation ranges from 0.2 – 2.1×1026 ergs, whilst the total energy dissipated ranges from 1.3 – 6.3×1026 ergs. For all cases, a stronger overlying field results in higher energy storage and dissipation. For the cancellation and emergence simulations, motion perpendicular to the overlying field results in the highest values. For the flyby simulations, motion parallel to the overlying field gives the highest values. In all cases, the free energy built up is sufficient to explain small-scale phenomena such as X-ray bright points or nanoflares. In addition, if scaled for the correct number of magnetic elements for the volume considered, the energy continually dissipated provides a significant fraction of the quiet Sun coronal heating budget.
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We present a new model for the Sun's global photospheric magnetic field during a deep minimum of activity, in which no active regions emerge. The emergence and subsequent evolution of small- scale magnetic features across the full solar surface is simulated, subject to the influence of a global supergranular flow pattern. Visually, the resulting simulated magnetograms reproduce the typical structure and scale observed in quiet Sun magnetograms. Quantitatively, the simulation quickly reaches a steady state, resulting in a mean field and flux distribution that are in good agreement with those determined from observations. A potential coronal magnetic field is extrapolated from the simulated full Sun magnetograms, to consider the implications of such a quiet photospheric magnetic field on the corona and inner heliosphere. The bulk of the coronal magnetic field closes very low down, in short connections between small-scale features in the simulated magnetic network. Just 0.1% of the photospheric magnetic flux is found to be open at 2:5 Rʘ, around 10 - 100 times less than that determined for typical HMI synoptic map observations. If such conditions were to exist on the Sun, this would lead to a significantly weaker interplanetary magnetic field than is presently observed, and hence a much higher cosmic ray flux at Earth.
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Turbulence and internal waves are probably important in generating layered structures in frontal region of marine environments (e.g. near river plumes outflow into the sea). Here we investigate the role of normal modes of internal waves in generation of layered structure in a part of Persian Gulf where river plume inters and in some laboratory experiments. The model prediction and observations show that layers so formed have a thickness of about 2m based on salinity variations with depth, but layers (about 5m) based on horizontal velocity profiles. Laboratory experiments with a plume outflow in a Filling Box profile also generate normal mode layered structure with 21H=0.5 (where A is layer thickness and H is the plume depth). In these experiments as Re of the flow is smaller than the Re of field flow. The normal modes are substantially dissipated with depth. Typical values of dissipation factor is about 0(100). This factor for field observation is 0(10) which is still substantial. Qualitative comparison between layered structure in field and laboratory is good. It should be emphasized that field observation is for semi-enclosed seas but the laboratory experiments are for enclosed region. Hence some of the discrepancies in the results of two cases are inevitable. Layered structures in marine environments are also produced by double diffusive convection. In this region this should be studied separately.
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Current dynamics in the Strait of Bonifacio (south Corsica) were investigated at a small scale during the STELLAMARE1 multidisciplinary cruise in summer 2012, using in situ measurements and modeling data. The Strait of Bonifacio is a particularly sensitive marine area in which specific conservation measures have been taken to preserve the natural environment and wild species. Good knowledge of the hydrodynamics in this area is essential to optimize the Marine Protected Area's management rules. Therefore, we used a high-resolution model (400 m) based on the MARS3D code to investigate the main flux exchanges and to formulate certain hypotheses about the formation of possible eddy structures. The aim of the present paper is first to synthetize the results obtained by combining Acoustic Doppler Current Profiler data, hydrological parameters, Lagrangian drifter data, and satellite observations such as MODIS OC5 chlorophyll a data or Metop-A AVHRR Sea Surface Temperature (SST) data. These elements are then used to validate the presence of the mesoscale eddies simulated by the model and their recurrence outside the cruise period. To complete the analysis, the response of the 3D hydrodynamical model was evaluated under two opposing wind systems and certain biases were detected. Strong velocities up to 1 m s(-1) were recorded in the east part due to the Venturi effect; a complementary system of vortices governed by Coriolis effect and west wind was observed in the west part, and horizontal stratification in the central part has been identified under typical wind condition.
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This paper applies a stochastic viability approach to a tropical small-scale fishery, offering a theoretical and empirical example of ecosystem-based fishery management approach that accounts for food security. The model integrates multi-species, multi-fleet and uncertainty as well as profitability, food production, and demographic growth. It is calibrated over the period 2006–2010 using monthly catch and effort data from the French Guiana's coastal fishery, involving thirteen species and four fleets. Using projections at the horizon 2040, different management strategies and scenarios are compared from a viability viewpoint, thus accounting for biodiversity preservation, fleet profitability and food security. The analysis shows that under certain conditions, viable options can be identified which allow fishing intensity and production to be increased to respond to food security requirements but with minimum impacts on the marine resources.
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The report of the proceedings of the New Delhi workshop on the SSF Guidelines (Voluntary Guidelines for Securing Sustainable Small-scale Fisheries in the Context of Food Security and Poverty Eradication). The workshop brought together 95 participants from 13 states representing civil society organizations. governments, FAO, and fishworker organizations from both the marine and inland fisheries sectors. This report will be found useful for fishworker organizations, researchers, policy makers, members of civil society and anyone interested in small-scale fisheries, tenure rights, social development, livelihoods, post harvest and trade and disasters and climate change.
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This research develops four case studies on small-scale fisheries in Central America located within indigenous territories. The ngöbe Bugle Conte Burica Territory in the south of Costa Rica, the Garífuna territory in nueva Armenia Honduras, the Rama territory in Nicaragua and the ngöbe Bugle territory in Bocas del Toro, Panamá. This is one of the first studies focusing on indigenous territories, artisanal fisheries and SSF guidelines. The cases are a first approach to discussing and analyzing relevant social and human rights issues related to conservation of marine resources and fisheries management in these territories. The cases discussed between other issues of interest, the relationships between marine protected areas under different governance models and issues related to the strengthening of the small-scale fisheries of these indigenous populations and marine fishing territories. They highlight sustainability, governance, land tenure and access to fishing resources, gender, traditional knowledge importance and new challenges as climate change.
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Integral to achieving the SSF Guidelines goal of targeting the most vulnerable and marginalized persons and eliminating discrimination is the need to have adequate understanding of the power relations and intersectionalities that shape access to and control over marine and other resources according to gender, age, race, ethnicity, labour and migratory status, disability, geographic location and other characteristics relevant in each national contexts. This monograph identifies and explores the key social relations and dynamics in the SSF fisheries sector in South Africa impacting the implementation of the SSF Guidelines. The monograph will be useful for researchers, scientists, fishworker organizations, environmentalists and anyone interested in the protection of marine biodiversity and the promotion of sustainable fisheries management.
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Abstract The potential impacts of climate change and environmental variability are already evident in most parts of the world, which is witnessing increasing temperature rates and prolonged flood or drought conditions that affect agriculture activities and nature-dependent livelihoods. This study was conducted in Mwanga District in the Kilimanjaro region of Tanzania to assess the nature and impacts of climate change and environmental variability on agriculture-dependent livelihoods and the adaptation strategies adopted by small-scale rural farmers. To attain its objective, the study employed a mixed methods approach in which both qualitative and quantitative techniques were used. The study shows that farmers are highly aware of their local environment and are conscious of the ways environmental changes affect their livelihoods. Farmers perceived that changes in climatic variables such as rainfall and temperature had occurred in their area over the period of three decades, and associated these changes with climate change and environmental variability. Farmers’ perceptions were confirmed by the evidence from rainfall and temperature data obtained from local and national weather stations, which showed that temperature and rainfall in the study area had become more variable over the past three decades. Farmers’ knowledge and perceptions of climate change vary depending on the location, age and gender of the respondents. The findings show that the farmers have limited understanding of the causes of climatic conditions and environmental variability, as some respondents associated climate change and environmental variability with social, cultural and religious factors. This study suggests that, despite the changing climatic conditions and environmental variability, farmers have developed and implemented a number of agriculture adaptation strategies that enable them to reduce their vulnerability to the changing conditions. The findings show that agriculture adaptation strategies employ both planned and autonomous adaptation strategies. However, the study shows that increasing drought conditions, rainfall variability, declining soil fertility and use of cheap farming technology are among the challenges that limit effective implementation of agriculture adaptation strategies. This study recommends further research on the varieties of drought-resilient crops, the development of small-scale irrigation schemes to reduce dependence on rain-fed agriculture, and the improvement of crop production in a given plot of land. In respect of the development of adaptation strategies, the study recommends the involvement of the local farmers and consideration of their knowledge and experience in the farming activities as well as the conditions of their local environment. Thus, the findings of this study may be helpful at various levels of decision making with regard to the development of climate change and environmental variability policies and strategies towards reducing farmers’ vulnerability to current and expected future changes.
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Deep-fat frying is susceptible to induce the formation of undesirable products as lipid oxidation products and acrylamide in fried foods. Plantain chips produced by small-scale producers are sold to consumers without any control. The objective of this study was to evaluate the quality of plantain chips from local producers in relation to production process parameters and oils, and to identify the limiting factors for the production of acrylamide in plantain chips. Samples of frying oils and plantain chips prepared with either palm olein or soybean oil were collected from 10 producers in Yaoundé. Quality parameters determined in this study were: fatty acid composition of the oils, determined by gas chromatography (GC) of free acid methyl ester; trans fatty acids, determined by Fourier transform infra-red spectroscopy; Tocopherols and tocotrienols as markers of nutritional quality were analyzed by High Performance Liquid Chromatography in isocratic mode. Free fatty acids and acylglycerols as markers of lipid hydrolysis were analyzed by GC of trimethylsilyl derivatives of glycerides. Conjugated dienes, Anisidine value and viscosity as markers of lipid oxidation and thermal decomposition of the oils; acrylamide which is formed through Maillard reaction and identified as a toxic compound in various fried products. Asparagine content of the raw fresh plantain powder was also determined. Fatty acid composition of palm oleins was stable within a day of intermittent frying. In soybean oils, about 57% and 62.5% of linoleic and linolenic acids were lost but trans fatty acids were not detected. Soybean oils were partly hydrolysed leading to the formation of free fatty acids, monoacylglycerols and diacylglycerols. In both oils, tocopherols and tocotrienols contents decreased significantly by about 50%. Anisidine value (AV) and polymers contents increased slightly in fried palm oleins while conjugated hydroperoxides, AV and polymers greatly increased in soybean oils. Acrylamide was not detected in the chips. This is explained by the absence of asparagine in the raw plantains, the other acrylamide precursors being present. This study shows that the plantain chips prepared at the small-scale level in Yaounde with palm olein are of good quality regarding oxidation and hydrolysis parameters and the absence of acrylamide. In contrast, oxidation developed with soybean oil whose usage for frying should be questioned. Considering that asparagine is the limiting factor for the formation of acrylamide in plantain chips, its content depending on several factors such as production parameters and maturity stage should be explored.
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Environmental heterogeneity in coastal lagoons is expected to facilitate local adaptation in response to different ecological conditions, causing significant genetic structuring within lagoon populations at a small scale and also differentiation between lagoons. However, these patterns and processes of genetic structuring are still poorly understood. The aims of our study were (1) to seek genetic structure at a small scale in Cerastoderma glaucum inside the Mar Menor coastal lagoon using a mitochondrial DNA marker (COI) that has previously detected genetic differentiation inside the lagoon in other species and (2) to evaluate the influence of extreme environmental conditions and habitat discontinuity on its genetic composition. The results indicate high levels of haplotype diversity and low values of nucleotide diversity. COI data provide evidence of significant population differentiation among some localities within the lagoon. Limited gene flow and unstable population dynamics (i.e. fluctuations in population size caused by local extinction and recolonization), probably due to the high environmental heterogeneity, could generate the small-scale genetic divergence detected between populations within the lagoon.
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The challenge for wastewater professionals is to design and operate treatment processes that support human well being and are environmentally sensitive throughout the life-cycle. This research focuses on one technology for small-scale wastewater treatment: the vertical flow constructed wetland (VFCW), which is herein investigated for the capacity to remove ammonium and nitrate nitrogen from wastewater. Hydraulic regime and presence/absence of vegetation are the basis for a three-phase bench scale experiment to determine oxygen transfer and nitrogen fate in VFCWs. Results show that 90% NH4+-N removal is achieved in aerobic downflow columns, 60% NO3--N removal occurs in anaerobic upflow columns, and 60% removal of total nitrogen can be achieved in downflow-upflow in-series. The experimental results are studied further using a variably saturated flow and reactive transport model, which allows a mechanistic explanation of the fate and transport of oxygen and nitrogen. The model clarifies the mechanisms of oxygen transport and nitrogen consumption, and clarifies the need for readily biodegradable COD for denitrification. A VFCW is then compared to a horizontal flow constructed wetland (HFCW) for life cycle environmental impacts. High areal emissions of greenhouse gases from VFCWs compared to HFCWs are the driver for the study. The assessment shows that because a VFCW is only 25% of the volume of an HFCW designed for the same treatment quality, the VFCW has only 25-30% of HFCW impacts over 12 impact categories and 3 damage categories. Results show that impacts could be reduced by design improvements. Design recommendations are downflow wetlands for nitrification, upflow wetlands for denitrification, series wetlands for total nitrogen removal, hydraulic load of 142 L/m2d, 30 cm downflow wetland depth, 1.0 m upflow wetland depth, recycle, vegetation and medium-grained sand. These improvements will optimize nitrogen removal, minimize gaseous emissions, and reduce wetland material requirements, thus reducing environmental impact without sacrificing wastewater treatment quality.
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Simarouba glauca, a non-edible oilseed crop native to South Florida, is gaining popularity as a feedstock for the production of biodiesel. The University of Agriculture Sciences in Bangalore, India has developed a biodiesel production model based on the principles of decentralization, small scales, and multiple fuel sources. Success of such a program depends on conversion efficiencies at multiple stages. The conversion efficiency of the field-level, decentralized production model was compared with the in-laboratory conversion efficiency benchmark. The study indicated that the field-level model conversion efficiency was less than that of the lab-scale set up. The fuel qualities and characteristics of the Simarouba glauca biodiesel were tested and found to be the standards required for fuel designation. However, this research suggests that for Simarouba glauca to be widely accepted as a biodiesel feedstock further investigation is still required.
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Trammel net discards in four southern European areas were considerable, with a total of 137 species (79.7% of the total) discarded 65, 105, 46 and 32 species in the Basque country (Spain), Algarve (Portugal), Gulf of Cadiz (Spain) and Cyclades islands (Greece), respectively. The overall discard rate in terms of catch numbers ranged from 15% for the Cyclades to 49% for the Algarve, with the high discard rate for the latter due largely to small pelagic fishes. Discards in the four areas consisted mainly of Trisopterus luscus (Basque country), Scomber japonicus (Algarve), Torpedo torpedo (Cadiz) and Sardina pilchardus (all three areas), and Diplodus annularis in the Cyclades. Strong seasonal variation in discarding was found, reflecting differences in metiers and the versatility of trammel nets as a gear. Discarding, both in terms of numbers of species and individuals decreased with increasing inner panel mesh size. The main reasons for discarding were: (1) species of no or low commercial value (e.g. Scomber japonicus; Torpedo torpedo), (2) commercial species that were damaged or spoiled (e.g. Merluccius merluccius), (3) undersized commercial species (e.g. Lophius piscatorius), and (4) species of commercial value but not caught in sufficient quantities to warrant sale (e.g. Sardina pilchardus). A decrease in soak time together with the appropriate choice of mesh sizes could contribute to a reduction in discarding and to improved sustainability and use of scarce resources in the small-scale, inshore multi-species fisheries of southern Europe. (C) 2007 Elsevier B.V. All rights reserved.