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Urban Green Areas – their functions under a changing lifestyle of local people, the example of Hanoi
(2013)
Hanoi is a rapidly developing city - in terms of area, population and economy. It also has to face social and environmental problems that often accompany the fast development of a city. Increasing environmental pollution leads to a decrease in living conditions, such as clean water, housing, social services, etc., for most of the city’s inhabitants. Other well-known social problems in cities worldwide also occur in Hanoi nowadays, for example inequality, food supply, and unemployment. In addition, the society is altering; lifestyle- change is a permanent process. Today, it seems that the changing process in Asian countries is rather leap-frogging than continuously. Although many research projects concerning to urban green areas in Hanoi have been completed recently, less is known about utilization of parks&gardens in a practical and systematic way. This study aims at contributing to fulfills the gaps with up-to-date facts and figures of parks’ utilization in the inner city of Hanoi. Based on “grounded theory”, triangular methodology was applied to collect empirical data in four main parks in the inner city of Hanoi namely: Thong Nhat, Bach Thao, Hoan Kiem, and Lenin. Scientific observations, visitor countings were done in 2010-2011; including 2143 face-to-face interviews to park users covering the course of the year and a small online-poll of 113 responses. Thirteen interviews with experts have been done in several phases and taken into account for discussing and testing hypotheses. Empirical results have shown that utilization of the parks is in abundance in terms of the use - numbers as well as activities. A comparison between the courses of the day for parks in Berlin and Hanoi shown that the time of using parks in Hanoi is earlier in the day. In details, there is 25% and 1.4% of total daily visitors went to parks in Hanoi and Berlin,, respectively. However, the biggest peak in park-visiting time for both cities is in the afternoon. The findings also clarified that students and retirees are the major users even though there is some different in structures of park user among the four parks. The length of stay depends on how large and interesting a park is. In this aspect, Hanoi parks are very poor in facilities showing by a long list of missing facilities in the parks. However, as there is no alternative, parks in Hanoi still attract a high number of visitors. In general, results from this study have shown a close relationship among socio-economic and political situations in Vietnam with UGAs and its utilization. Influencing factors on parks’ utilization were also indentified, which are social changes, lifestyle changes, economic situation, conflicts in land usage, and maintaining cost for UGAs. Three given hypotheses were confirmed: i) the demand of public UGAs in inner Hanoi will grow mid-term and increase strongly long-term; ii) Hanoi’s residents will claim strongly for more parks in the future; ii) The number of conflicts inside the area of UGAs, among the visitors will occur very soon and require a specific master plan for the development and the management of UGAs. Finally, based on the weaknesses of UGAs in Hanoi recently, two groups of recommendations were also suggested to improve UGAs. Firstly, in terms of quality – quantity: • Retain each square meter of green space as UGA – do not unblock any green space for construction; • The existing UGA have to be well maintained. Secondly, in terms of management – planning: • Elaborate a UGA-masterplan for (inner) Hanoi; • Keep UGA management in the responsibility of public bodies; • Implement participation of affected population defector in the process of planning and management (as it has already been written in planning guidelines); • Be aware of potential conflicts among park user groups; • Establish an UGA monitoring system – involving regular (or even permanent) countings based on up-to-date technology; Realize horizontal partnering structures.
Autoclaved aerated concrete (AAC) is a building material that combines heat insulation
properties with sufficient mechanical strength for masonry construction. Compared to
ordinary concrete, the matrix is highly porous (>50%) and hardened by a hydrothermal curing
process at 150°C - 200°C. During this process, quartz sand and portlandite react to form first
calcium silicate hydrates (C-(A)-S-H) with Ca/Si ratios <1.3 and then tobermorite. Especially
tobermorite, which has a much larger crystallite size than C-(A)-S-H, provides improved
mechanical strength. This reaction sequence is influenced by many parameters and
additives of which calcium sulfate is probably the most important. Despite several attempts to
investigate these hydrothermal reactions, the actual reaction mechanism involved when
adding sulfate ions is not fully understood. It has been suggested that the addition of ca.
1.5 wt% significantly improves the mechanical properties due to the enhanced formation and
arrangement of tobermorite in the porous matrix. Since the sulfate content in AAC waste is
exceeding regulatory threshold for low-quality reuse in some countries, the aim of this study
was to investigate in detail the reaction mechanisms involving sulfate addition. Such
knowledge may open up the possibility to improve AAC production and to avoid the need for
sulfate addition. To achieve this goal, this research work focused on investigating the
hydrothermal curing process to determine the sequence of hydrothermal reactions and the
spatial distribution of the phases formed. For this purpose, a new setup for in situ X-ray
diffraction was specifically designed to study hydrothermal reactions and to conduct time
intensive experiments on a normal laboratory diffractometer. In order to quantitatively
evaluate the in situ measurements by Rietveld analysis using TOPAS, it was also necessary
to develop atomistic structure models for C-(A)-S-H phases. This was made possible by
adopting a supercell approach that was previously used to describe turbostratically stacked
clay minerals. The structure models, derived from tobermorite, are placed in an otherwise
empty supercell to simulate the C-(A)-S-H nanostructure. Adopting these methodological
advances, it was possible to obtain absolute phase quantities from in situ data and to track
the reaction kinetics of the hydrothermal curing process. These results were then combined
with ex situ X-ray diffraction and scanning electron microscopy. Confirming previous studies,
the major effect of sulfate ions was the formation and decomposition of hydroxylellestadite. It
was further revealed that C-(A)-S-H formation was delayed during hydroxylellestadite
formation, which is supposed to support the silicate ion diffusion and hence the tobermorite
formation at a stage critical for improved hardening of AAC. This can be linked to the
formation of lower amounts of capillary pores in the range of 1-5 µm, as observed by
scanning electron microscopy, and therefore a lower concentration of inherent defects that
resulted in the improved mechanical properties. This research work highlights how important the spatial distribution of crystallites is for the properties of a building material and how this
distribution can be influenced by small alterations in reaction chemistry.
There is broad scientific consensus that current food systems are neither sustainable nor resilient: many agricultural practices are very resource-intensive and responsible for a large share of global emissions and loss of biodiversity. Consequently, current systems put large pressure on planetary boundaries. According to economic theory, food prices form when there is a balance between supply and demand. Yet, due to the neglect of negative external effects, effective prices are often far from representing the ‘true costs’. Current studies show that especially animal-based foodstuff entails vast external costs that currently stay unaccounted for in market prices. Against this background, we explore how informational campaigning on agricultural externalities can contribute to consumer awareness and tolerance of this matter. Further, we investigate the socially just design of monetary incentives and their implementation potentials and challenges. This study builds on the informational campaign of a German supermarket displaying products with two price tags: one of the current market price and the other displaying the ‘true’ price, which includes several environmental externalities calculated with True Cost Accounting (TCA). Based on interpretations of a consumer survey and a number of expert interviews, in this article we approach the potentials and obstacles of TCA as a communication tool and the challenges of its factual implementation in agri-food networks. Our results show that consumers are generally interested in the topic of true food pricing and would to a certain extent be willing to pay ‘true prices’ of the inquired foods. However, insufficient transparency and unjust distribution of wealth are feared to bring about communication and social justice concerns in the implementation of TCA. When introducing TCA into current discourse, it is therefore important to develop measures that are socially cautious and backed by relevant legal framework conditions. This poses the chance to create a fair playing (‘polluter pays’) with a clear assignment of responsibilities to policy makers, and practitioners in addition to customers.
Tidal flats represent the transition zone between the terrestrial and marine realm. They are subject to pronounced dynamics due to distinct tidal and seasonal variations of physical, chemical, and biological parameters significantly influencing redox-sensitive element cycles. Thus, redox-sensitive trace metals may be suitable indicators for variations in bioproductivity and microbial activity. Therefore, seasonal and tidal dynamics of manganese, iron, molybdenum, uranium, and vanadium were studied in the water column and sediments of tidal systems of the German Wadden Sea (southern North Sea) in the years 2007 to 2009 involving also previously analysed data from year 2002. To demonstrate the response of the trace metal cycles on phytoplankton blooms and enhanced biological activity time series data of nutrients and phytoplankton dynamics were also involved in this study. Pronounced cycling is seen for pelagic manganese revealing distinctly higher values during low tide. Complex seasonal cycling showing maxima of dissolved manganese in spring and late summer and a depletion period in early summer is caused by benthic-pelagic coupling and reflection of exhaustion and replenishing periods in the surface sediments. Vanadium dynamics are coupled to the manganese cycling due to vanadium scavenging and release during manganese oxide formation and reduction, respectively. Molybdenum and uranium behave almost conservatively following changes in salinity and thus, being slightly enhanced during high tide. Deviations from conservative behaviour are found to occur during breakdowns of summer phytoplankton blooms. In the following, significant enrichments of manganese, molybdenum, iron, and uranium are observed in the shallow pore waters. These coherences are assumed to be caused by a tight coupling of geochemical, biological, and sedimentological processes. Intense release of organic matter during the breakdowns of algae blooms leads together with enhanced bacterial activity in summer to the formation of organic- and trace metal-rich aggregates which are deposited and incorporated into the tidal surface sediments. Microbial decomposition of the aggregates and corresponding shifts in redox-conditions effect a release of dissolved trace metals into the pore water. Subsequently, the trace metals are fixed in the sediment as sulphides, adsorbed to organic compounds or released to the overlying bottom water. Furthermore, two tidal systems, one from the East Frisian and one from the North Frisian Wadden Sea are compared. Although, both areas show different hydrodynamical, sedimentological, and ecological conditions similar manganese dynamics are observed implying that this is a common behaviour in the entire Wadden Sea. However, distinct quantitative differences appear showing a 6-fold higher level of dissolved manganese in the water column of the East Frisian area. This is explained by a higher manganese release from tidal flat sediments and a larger sediment area/water volume ratio compared to the North Frisian area. Detailed time-series data of the nutrients phosphate, silica, and nitrite+nitrate are used to verify model simulations and to calculate nutrient export budgets considering tidal and seasonal variations. The model results imply an export of nutrients from the tidal flats into the open waters of the German Bight which is in the same order of magnitude as the combined discharge of the rivers Elbe, Weser, and Ems. To investigate the importance of the Wadden Sea as a potential manganese source for the North Sea, transects were carried out into several tidal flat areas of the North Frisian Wadden Sea. The results suggest that the North Frisian Wadden Sea is a less important source for dissolved manganese compared to the East Frisian area. In contrary, the export of particulate manganese seems to be more important showing distinctly higher concentrations in the North Frisian study areas in summer. The influence of sediment permeability and bioturbation on trace metal budgets of the pore waters are investigated in natural and experimentally manipulated tidal flat sediments. Advective pore water transport in highly permeable sandy sediments and bioturbation promote exchange processes at the sediment/water interface probably leading to reduced nutrient and trace metal enrichments in the shallow pore waters. Furthermore, the penetration of oxygen into deeper sediment layers induces a release of sulphidic bound molybdenum to the pore water. During laboratory experiments with natural anoxic sediments an effective oxidative molybdenum release is determined during resuspension of the sediments in oxic seawater. Thus, pronounced sediment resuspension during storm events is suggested to cause significant release of molybdate from displaced anoxic sediment components thereby enhancing the molybdate level of the open water column. In addition to the examination of recent biogeochemical processes, the paleo-environmental influence on geochemical and microbiological processes in Holocene and Pleistocene sediments of the East Frisian study area were analysed in an interdisciplinary study. It is found that the microbial abundance and activity are higher in the Holocene than in the Pleistocene sediments. However, this is mainly caused by present environmental conditions. The impact of the paleo-environment on the microbiology is less pronounced. The lithological succession affects hydrological processes which enable the transfer of electron donors and acceptors for present early diagenetic processes into deep sediment layers. The paleo-environmental imprint is still detectable but the modern biogeochemical processes dominate in the sediment-pore water system.
This thesis aims to investigate effects of anthropogenic environmental impact on the Richards Bay area. Located on the east coast of South Africa, Richards Bay Harbour evolved into the country’s premier bulk cargo port. The Associated change in land-use and industrial as well as agricultural pollution pose environmental, ecological and human health risks. Here, sedimentological and geochemical investigations focus on the port as final sink for environmental and industrial pollutants, such as metal concentrations, organochlorine pesticides and microplastics.
The study is based on investigations of surface sediment samples from the water-sediment interface to identify spatial distribution patterns, as well as sediment cores to follow temporal changes. Endmember modelling of grainsize distributions, proved to be a viable parameter to distinguish different accumulation spaces and enabled the classification into six harbour sub-basins. Subsequent investigations on the content of microplastics, Polyethylene terephthalate (PET) and Low-density polyethylene (LDPE), showed that these different types of microplastics predominate in two different areas: PET appears to be directly tied to higher populated (tourism) beaches, while LDPE is deposited in low-current sub-basins. Increased metal concentrations link to activities at the bulk cargo berths, where especially Cr and Cu concentrations exceeded the local sediment guideline thresholds. In the areas of high metal concentrations, bioindicators (ostracods, foraminiferas, diatoms) also indicate increased shares of malformed specimens. Multiple recovered sediment cores recorded changes in recent export practices, indicating ceased Cu handling and increased Cr handling over the past decade. Noticing multiple possible influencing factors on elemental distributions, created by the surrounding geological and industrial impact, the usefulness of different normalisers (Al, Fe, Rb, Ti and silt fraction) for Cr, Cu, Co and Pb concentrations was compared and site specific baseline metal concentrations were defined. This identified Al and Rb to be effective normalisers in Richards Bay and Fe or Ti to be affected by local conditions. Data of organochlorine pesticide pollution was gathered in the area of Richards Bay, Goedertrouw Dam and Umlalazi River. The two dominant groups of contaminants detected are dichlorodiphenyltrichloroethanes (ΣDDT, 12 – 350 ng g-1), linked to the use of malaria vector control, and hexachlorocyclohexanes (ΣHCH 35 – 230 ng g-1), an agricultural insecticide. Both indicate recent entry and exceed sediment quality guideline limits, raising concern for local communities and estuarine environments. Seismic data was used to investigate the preindustrial evolution of the incised valley system and bayhead delta at Richards Bay Harbour. A stratigraphically supported development model was created. The thesis shows that harbour sediment is an important sink for inorganic and organic contaminants. Each investigation on environmental pollutants, such as metals, pesticides, microplastics or bioindicator analyses, indicates their deposition in distinct harbour sub-basins. Therefore, their effect can be spatially differentiated and related to plausible sources of pollution. Richards Bay thus represents a variously affected system along the South African coast, in which it is necessary to take environmental protection measures in terms of sustainable and environmentally friendly management.
This work first sets out to find if economic, ecological, or social incentives drive consumers towards or against dietary decisions (Contribution A). It then develops a framework of TCA for food to describe economically conveyed incentives that are tied to ecological and social indicators within the food market (Contribution B). The framework is subsequently enhanced and broadened to include a deeper understanding and broader field of indicators for more holistic TCA calculations (Contributions C and D). Lastly, based on these calculations, TCA of food is implemented in a factual use case as the framework and calculations are deployed for commodities of a German supermarket chain; then consumer, as well as expert feedback is used for the discussion on socially responsible campaigning and policy change (Contribution E).
Although the Pleistocene deposits exposed in the steep coastal cliffs of Mecklenburg-Vorpommern have been studied for more than a century, the depositional conditions of many lithostratigraphic units remain unclear. There is, in particular, a question whether the individual tills (locally more than 9 successive till units) are mainly subglacial deposits or resedimented (mass flows) in origin (at least in part). The Pleistocene deposits preserve information concerning the former glacial depositional processes. Detailed micromorphological analysis of these deposits can provide key information regarding these processes and thereby aid in the reconstruction of former glacial environments. The island of Rügen is located on the southwestern Baltic Sea coast and was situated in the marginal zone of the Scandinavian Ice Sheet during the last glacial period (Weichselian). Therefore, the region is considered as an ideal area for reconstructing the complex fluctuations in the position of the margin of this ice sheet as it expanded across the Baltic Sea and into northern Germany. Successive glacial advances and retreats of the ice sheet can be reconstructed by specific glacial sedimentation processes and flow-direction criteria derived from a variety of glacial deposits. The investigation area is located near Sassnitz on Rügen, where an imbricated and folded Weichselian succession disconformably overlies Maastrichtian chalk bedrock. The individual till units were sampled for micromorphological analyses to identify the former depositional conditions. Detailed description of the sedimentology and variation in facies, the description of macroscale deformation structures provides the context for the detailed micromorphology study. The three dimensional analysis of the microfabrics is based on the microstructural mapping methodology which enables the identification and interpretation of polyphase deformation within subglacial sediments.
The deep geological underground represents an important georesource for the short-
term storage of renewable energy and the long-term reduction of greenhouse gas emissions. To ensure the economic viability and safety of any subsurface storage project, detailed characterisation of the quality and integrity of the reservoir and its cap rock is required. This characterisation includes the accurate determination of the petrophysical properties, such as porosity and permeability, as well as the potential mineral reactions, such as the dissolution of reactive phases, which may occur during the lifespan of such a project. Clay minerals are common components of many reservoir systems and, depending on their type and structure, can have a significant impact on storage and transport properties. These processes are, however, currently not well understood. In order to address these issues, the main focus of this thesis is on mineralogical analyses using X-ray diffraction (XRD) and microstructural studies using focused ion beam scanning electron microscopy (FIB-SEM) together with micro X-ray computed tomography (µXCT) to gain a better understanding of the influence of clay minerals on reservoir and cap rock properties.
A central part of this thesis focuses on the analysis of clay minerals and pore structures of the Bebertal Sandstone of the Parchim Formation (Early Permian, Upper Rotliegend), which is considered a natural analogue for the tight reservoir sandstones of the North German Basin. Two illite polytypes with a variety of characteristic structures have been identified in the Bebertal sandstone. Disordered 1Md illite forms the majority of the observed structures, which include omnipresent grain coatings, altered permeable feldspar grains and pore-filling meshwork structures. Trans-vacant 1M illite represents the second and youngest generation of authigenic illite and occurs as fibrous to lath-shaped particles that grew into open pore spaces and led to a significant reduction in porosity and permeability during late diagenesis. Based on these results, a model for the formation of illite polytypes in the aeolian layers of the Bebertal sandstone was developed that describes the temporal and spatial evolution of porosity and permeability during diagenesis. Information from this model was then used to improve the prediction of permeability of the Bebertal sandstone based on µXCT pore space models and direct numerical simulations. To achieve this, a micro-scale pore space model was created that allowed the simulation of permeability reduction by clay minerals by including nanoporous illite domains based on a novel morphological algorithm. By performing Navier-Stokes-Brinkman simulations, more accurate predictions of permeabilities with respect to experimentally determined values were obtained compared to conventional Navier-Stokes simulations.
The detailed characterisation of the Bebertal sandstone has shown that natural reservoir rocks are usually complex heterogeneous systems with small-scale variations in texture,
composition, porosity and permeability. Flow-through experiments on the Bebertal sandstone revealed that the coupled geochemical and hydrodynamic processes that occur during the dissolution of calcite could not be predicted by reactive transport models. Therefore, as part of this thesis, a novel approach for developing synthetic sandstones at low temperatures based on geopolymer binder was developed. It is shown that simpler and more homogeneous porous materials can be produced with porosity and permeability values in the range of natural sandstones. These can be used to better understand the dynamic and coupled processes relevant to the storage of renewable energy in reservoir rocks through improved experimental constraints.
The final part of this thesis reports on a detailed clay mineral and pore space study of
three shale formations and one mudstone that were identified as potential seals for the Mt. Simon sandstone reservoir in the Illinois Basin. During the Illinois Basin - Decatur Project, this reservoir was used for the sequestration of one megaton of supercritical carbon dioxide. In order to better assess the quality of the sealing units and to better understand the role of the intergranular clay mineral matrix as potential pathway for fluid migration, a multi-scale evaluation was conducted that included thin section analysis, quantitative evaluation of minerals by scanning electron microscopy (QEMSCAN), mercury intrusion capillary pressure (MICP) measurements, quantitative XRD and high-resolution FIB-SEM. The results allow for the classification of the studied formations into primary and secondary seals and emphasise the importance of three-dimensional clay-mineral-related pore structure characterisations in cap rock studies. XRD proved the most reliable method for the identification and quantification of clay minerals in the studied cap rocks and mudstones. In contrast, FIB-SEM and QEMSCAN provided the spacial constraints for reconstructing fluid flow pathways within the clay mineral matrix.
Overall, this thesis highlights the importance of the precise identification of clay minerals in geological reservoirs and their cap rocks. It also illustrates the need for three-dimensional characterisation and modelling of the associated small pore structures for an improved understanding of the rocks diagenetic history as well as the prediction of the transport and storage properties of these crustal reservoir systems.
Pilot sites are currently used to test the performance of bentonite barriers for sealing high-level radioactive waste repositories, but the degree of mineral stability under enhanced thermal conditions remains a topic of debate. This study focuses on the SKB ABM5 experiment, which ran for 5 years (2012 to 2017) and locally reached a maximum temperature of 250 °C. Five bentonites were investigated using XRD with Rietveld refinement, SEM-EDX and by measuring pH, CEC and EC. Samples extracted from bentonite blocks at 0.1, 1, 4 and 7 cm away from the heating pipe showed various stages of alteration related to the horizontal thermal gradient. Bentonites close to the contact with lower CEC values showed smectite alterations in the form of tetrahedral substitution of Si4+ by Al3+ and some octahedral metal substitutions, probably related to ferric/ferrous iron derived from corrosion of the heater during oxidative boiling, with pyrite dissolution and acidity occurring in some bentonite layers. This alteration was furthermore associated with higher amounts of hematite and minor calcite dissolution. However, as none of the bentonites showed any smectite loss and only displayed stronger alterations at the heater–bentonite contact, the sealants are considered to have remained largely intact.
The UNESCO Man and the Biosphere Programme has been active in South Africa for almost 20 years. The country currently has six designated biosphere reserves with a few sites in various stages of the nomination process. Within the South African context, agencies are using a series of seemingly different instruments to practice landscape-scale management. The UNESCO biosphere reserve concept sometimes finds it difficult to obtain prominence amongst these different landscape initiatives. Biosphere reserves are special sites wherein sustainable development is promoted. For this reason, the biosphere reserve concept has much to offer towards long-term sustainable socialecological land management. In our modern age of population growth, dwindling natural resources and a general disconnectedness of humans from nature due to large scale urbanization, there is an urgent need for innovative ways in which to showcase sustainable living practices. South Africa has limited natural, economic and social resources and therefore needs to prioritize where these resources could best be allocated. This dissertation comprises the history of the MAB Programme in South Africa, as well as a multicase study on five existing biosphere reserves. Results from this study indicated that not all biosphere reserves are equally effective in their implementation of the three functions of biosphere reserves and that all biosphere reserves in South Africa face an uncertain future due to pressing challenges. Collective results of the multicase study as well as literature reviews were used to inform options for the future effective implementation of the MAB Programme in South Africa. Options that could contribute towards effective biosphere reserves include more sustainable funding support, and community-based demonstration projects. In addition a new suite of criteria to inform the selection of future biosphere reserves was developed. Biosphere reserves need to be optimally located in order to secure long-term efficiency and effectiveness. These sites need to be representative of biodiversity, efficiently managed and persistent in the long run. Presently in South Africa, new sites for biosphere reserves are nominated in an ad hoc manner. Should their locations be selected discerningly, they offer many benefits to the South African social and environmental landscape that should be recognized and utilized. The final suite of selection criteria are structured according to four subsections, namely a general section that addresses national matters of general concern to the MAB Programme, and three sections covering the three biosphere reserve functions of conservation, sustainable development and logistic support. This suite of biosphere reserve selection criteria for South Africa is being put forward for deliberation and discussion at local, provincial and national level. It has the potential to be of valuable assistance in selection processes for future effective and efficient biosphere reserves that will proudly earn their place in the South African landscape as “special places for people and nature”.