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This thesis deals with the energy system transformation of coal-dependent developing countries in the context of climate change mitigation. It departs from the hypothesis that phasing-out the unabated use of coal for power generation, while scaling up carbon-free alternatives, represents a major challenge for coal-endowed developing countries and emerging economies. This challenge is constituted in multiple economic, political and societal determinants for sustained and expanded coal-use. This thesis adopts a political economy perspective and examines those determinants in detail. It focuses on how different societal and political actors are affected the use of coal, and interprets the distributional implications of reforms away from coal as key restrictions for their political feasibility. Given the heterogeneity in the historical, socio-economic, political, and institutional characteristics that different countries exhibit, which are hypothesized to impact on the drivers behind coal-use, this thesis adopts a case-study based approach. It focuses on two large Asian economies, Indonesia and India, as coal-endowed emerging economics with a pivotal relevance in global climate protection efforts. Three main chapters represent the core of this thesis. The first main chapter of this thesis examines the political economy of the power sector and coal mining in Indonesia, focusing on the drivers for the continued use of coal for electricity generation. It presents an expert-interview case study, based on the perspective of 90 expert stakeholder in Indonesia´s energy and climate policy, at national and subnational level. The study identifies key societal and political actors behind Indonesia´s energy- and climate policies driving coal-use, spells out their objectives, and examines how these actor-specific interests’ effect on energy and climate policies. The second main chapter of this thesis studies the implications of an Indian energy transition away from coal-use along three dimensions: the distributional impacts towards households, the implications for employment, and the impact on competitiveness of industries. The input-output based, distributional- incidence case study analyses the concentration of impacts for key societal groups affected by a coal phase-out and renewable energy phase-in, and its spatial distribution across Indian states and regions. The third main chapter of this thesis studies the cost-competitiveness of renewable energy alternatives to coal in Indonesia. The energy modelling based analysis shows how the cost-optimal composition of Indonesia´s power sector in coming decades would comprise high shares of coal-fired electricity. The three main chapters of this thesis identify political economy challenges to a transition away from coal, outlining how a successful coal phase-out will require focusing on its context-dependent distributional and political implications.
Significance of storm spatiotemporal variability and movement in flood hydrodynamic modelling
(2024)
This dissertation aims to explore the impact of various storm properties on computational flood modelling and to propose a method for integrating them into flood risk assessment. It focuses on three key areas:
Firstly, it examines within-storm variability, investigating how variations in storm intensity, duration, and spatial distribution affect runoff dynamics. Through a systematic theoretical approach, the study generates synthetic rainfall signals with different hyetograph variabilities and applies them to a hydrodynamic model. The results highlight the significant influence of storm spatiotemporal variability on runoff response, affecting peak discharge, hydrograph shapes, and flooded areas. Temporal variability emerges as particularly dominant, overshadowing spatial variability and other storm properties such as return period and volume. The study emphasizes the spatial dependency of these effects within the drainage network.
Secondly, it investigates the role of storm movement in flood modelling, recognizing its potential to alter runoff dynamics and inundation patterns. By generating synthetic rain hyetographs traversing the catchment area at varying velocities and directions, the study shows that storm movement significantly impacts runoff response and flood extents. Higher storm velocities lead to more pronounced peaks and faster runoff onsets, resulting in larger flooded areas. The direction of storm movement plays a crucial role, with storms aligning with the average stream direction causing the highest peaks and flooded areas. The magnitude of this influence varies depending on the location within the catchment.
Finally, the dissertation introduces a dynamic spatiotemporal rainfall model aimed at preserving storm event properties. Using an event-based approach, dynamic precipitation events are identified and regenerated, ensuring the conservation of storm spatiotemporal variability and movement characteristics. This facilitates the generation of more physically plausible and spatiotemporally coherent precipitation time series. The model prioritizes user accessibility, offering a practical tool for integrating storm properties into flood computation modelling and risk analysis frameworks. By addressing these aspects of storm behaviour, the dissertation contributes to enhancing the accuracy and effectiveness of flood modelling, thereby improving flood risk mitigation efforts.
Reliability assessment of pipeline failure factors has become a major concern for industrial firms involved in the transmission of oil and gas, where the requirement to limit these failure factors and their consequences, such as maintenance costs, is particularly significant. Pipelines were constructed throughout time to include safety precautions in order to offer a theoretical minimal failure rate for the pipeline's whole life. This strategy also includes the management of various failure causes as well as routine-based maintenance to assure the dependability of pipelines during their service life. However, the requirement to reduce the impact of these failure factors on pipelines has bolstered the use of reliability evaluation of failure factors on petroleum pipelines. The purpose of this study is to evaluate the reliability of oil pipelines in Nigeria, with emphasis on proposing operational and technical changes to enhance their resilience against unexpected failures. The thesis uses the regular Poisson, empirical, and compound Poisson processes to describe the number of common failure causes owing to corrosion, third-party damage, mechanically induced failure, operational mistakes, and natural hazards in repairable systems. The statistical analysis results serve as the foundation for time to failure modeling of petroleum pipelines utilizing Bayesian inference of the three-parameter Exponentiated Weibull distribution. The thesis also includes reliability probabilistic methods for assessing the influence of uncertainties in pipelines by comparing the First order reliability method (FORM) with the Second order reliability method (SORM) with demonstration on five distinct petroleum pipelines. The probability of failure and the reliability index for the five pipelines were calculated, along with the target reliability. Additionally, the influence of specific pipeline design parameters on the probability of failure was analyzed through sensitivity analysis. This analysis helps identify which design factors have the most significant impact on the likelihood of pipeline failure, allowing for more informed decisions in pipeline design and maintenance practices. By understanding these influences, it is possible to enhance the overall reliability and safety of the pipeline infrastructure. The framework developed in this thesis can be applied to enhance the performance of existing pipelines and serve as a good foundation for the design and implementation of new pipelines and similar infrastructures.
Benign prostatic hyperplasia (BPH) is considered an age-related disease of men with unknown etiopathophysiology. Chronic inflammation represents one of the most important pathophysiological mechanisms in this context, and there is also evidence for the involvement of autoimmune responses in an inflammatory environment in the prostate. Conventional therapeutic approaches for BPH are limited; however, immunosuppression by TNF (tumor necrosis factor)-𝛼 blockers seems to reduce symptoms in BPH patients due to the reduction of epithelial hyperplasia and macrophage-triggered inflammation. Therefore, this cumulative dissertation addresses biomarker-based BPH diagnosis by lens epithelium-derived growth factor splice variant 75 kDa (LEDGF/p75). LEDGF/p75 is an autoantigen that is overexpressed in solid tumors and functions as a stress-related transcriptional co-activator. It also plays an important role in cancer and DNA damage repair (DDR). The generation of CRISPR/Cas9-modified HEp-2 LEDGF deficient (KO) and HEp-2 LEDGF/p75 overexpressing (OE) cell lines provided new insights for the diagnosis and therapy of cancer and genetic disorders. Herein, IgG autoantibody reactivity to LEDGF/p75 was detected in patients with prostate cancer (PCa, n=89), bladder cancer (BCa, n=116), benign prostatic hyperplasia (BPH, n=103) and blood donors (BD, n=60) by indirect immunofluorescence assay (IFA) linear immunoassay (LIA) and Chritidia luciliae immunofluorescence test (CLIFT). In addition, proliferation and migration capacity as well as chemosensitivity of genome-edited cells were determined by optimized all-in-one approach, followed by investigation of DDR signaling pathways by Western blot and immunofluorescence. Surprisingly, no increased binding of autoantibodies (autoAbs) to LEDGF/p75 was detected in cancer patients, but autoAb reactivity to LEDGF/p75 O/E cells was unexpectedly increased in approximately 50% of patients with BPH. At the molecular level, LEDGF-deficient cells exhibit decreased proliferation and migration and increased sensitivity to the chemotherapeutic agent etoposide. A significantly Decreased DNA damage response could also be visualized. New diagnostic capabilities using HEp-2 cells overexpressing LEDGF/p75 or mitochondrial DNA as autoimmune targets could be used to identify BPH patients with autoimmune responses. Furthermore, this Thesis shows that LEDGF is not only involved in the recruitment of DNA damage response proteins, but also affects the proteosomal regulation of DDR signaling molecules.
The hetero-integration of group IV and III-V epitaxial layers on silicon (Si) substrates enables novel devices for optoelectronic and high-power applications. However, lattice and thermal mismachtes lead to an unavoidable formation of defects in hetero-epitaxy. The consideration of these defects is important in semiconductor devices as they affect material properties and impair the device performances. Besides the structural characterization of the unintentional introduced defects and the question of it’s origin, it is essential to evaluate their electrical activity in order to describe their impact on the device performance.
This work explores the electrical activity of threading dislocations (TDs) in Ge-rich SiGe heterostructures integrated on Si substrates as well as the electrical active defects introduced by the growth of aluminium-nitride (AlN) seed layers for the integration of gallium-nitride (GaN) on Si substrates.
I demonstrated a defect-related p-type conductivity of intrinsically grown Si ₀ ̣₀₆Ge ₀ ̣₉₄/Ge that reaffirms previous work of similar intrinsic Ge-based material. Moreover, I detailed the threading dislocation related leakage currents in rectifying devices, revealing a power law dependence on the threading dislocation density (TDD). By a variation of temperature I determined the dominant mechanism of transport of this leakage currents in different temperature regimes, for which I suggested possible interactions with TD related defect states. Through the reduction of leakage currents in the fabricated MOS capacitors I was able to examine an effective carrier concentration of 5-6x10¹⁵cm⁻³ in the nominally intrinsic Si ₀ ̣₀₆Ge ₀ ̣₉₄ epitaxial layer, which decreases down to 1x10¹⁵cm⁻³in the Ge buffer underneath. By applying deep level transient spectroscopy (DLTS) I found one dominant hole trap at mid-gap position confirming the presence of an TD-related effective generation-recombination center. In addition, I investigated the hole trapping kinetics of this defect level and associated it with point defects that are trapped in the strain field around threading dislocations.
I obtained insights into defect formation in the Si substrate and at the AlN/Si interface in dependence of the AlN growth temperature. A low temperature growth step prevented a deep in-diffusion of Al atoms into the Si substrate with simultaneous increase of the maximal p-type doping in the vicinity of the AlN/Si interface. Furthermore, I found a bulk hole trap inside the Si substrate at mid-gap position that showed an increase in density by applying a low temperature growth step. In contrast, the defect states at the AlN/Si interface decreased when a low temperature growth step was applied, in comparison to AlN layers grown at continuous high temperatures.
By the year 2539 almost 75% of all freshwater mollusc species within Europe will be lost. The transformation of natural ecosystems, the extension of infrastructure, as well as agriculture are the main threats. The Roman snail (Helix pomatia L. 1758) has been part of human culture for centuries and is protected by law as an endangered species in several regions, and at the same time regarded and treated as a pest, making the conservation of this species difficult.
The aim of this thesis was to create a better understanding of H. pomatia and its functional role within the ecosystem. Eight subpopulations were studied regarding its role within the food web, the use of empty shells as a mircohabitat and its influence on vegetation by showing food preferences. The latter, due to the fact, that a strong predation pressure can minimize habitats, which leads to higher pressure on the local vegetation and a limited possibility of shells being used as a microhabitat.
First, the relationships between H. pomatia individuals, subpopulations and their predators were analysed. The total number and percentage of shells that showed external attack marks by predators (32%) and internal utilization marks by Diptera pupae (45%) were analysed and correlated to morphometric traits of shells. Signs of external attack and internal utilization marks were positively correlated (R = 0.79; P = 0.020). External attacks were more regular in larger shells and internal utilization was more frequent in shells with higher body density.
The second chapter focuses on the shells of H. pomatia and their value as microhabitat for shell adopters in different vegetation forms and during two sample periods. Out of 618 collected shells, 91.4 % were inhabited and the average was 1.5 time higher in summer, than in autumn. The number of shell adopters per shell was 1.5 times higher in herbaceous vegetation, than in areas dominated by trees. Shell width (P = 0.008), but not shell height (P = 0.078) had a significant higher influence.
Finally, food preferences of H. pomatia were analysed, showing a pronounced preference for Urtica dioica (35% of all 697 feeding interactions) and plant litter (44%). Only 27 out of 143 available plant species were eaten and a literature review confirmed U. dioica as a food plant for 19 other terrestrial snail species. The width and height of the snail shells were related to the feeding height as smaller, juvenile snails fed higher in vegetation (384mm ± 327mm) compared to adult individuals (68mm ± 194mm) (P<0.001).
These results highlight the importance of H. pomatia in the studied ecosystem. H. pomatia is an important food source for predators and host for parasitoids, the shells offer habitat and refuge for soil organisms and as a relatively specialized herbivore and decomposer H. pomatia contributes to herbivory and nutrient cycling in ecosystems.
Hopefully this study may help to motivate future conservation efforts.
Due to environmental impacts from anthropomorphic climate change, countries from around the world are committed to an energy transition from fossil fuels to renewable and sustainable energy sources. The heating and cooling sector represents the largest share of total energy consumption globally, not only for domestic use but also for commercial and industrial purposes of which only 11% is covered by renewable energy. One renewable source, geothermal energy, has the potential to cover much of this demand, particularly heating demand, for the agriculture and food sector. Geothermal use in the agri-food industry continues to be positive overall, yet slow adoption and inconsistent growth have not met its potential as claimed by experts. This trend may be explained by a lack of coherent policy and initiatives from regulating government bodies. This research explores the relationship and the degree of correlation between government support, expressed in terms of policy incentives, and the growth of geothermal energy use in the agri-food sector. Two hypotheses are constructed to test this relationship. The first assumes that government support through policy leads to positive growth in geothermal argi-food, and the second assumes that no relationship exists. The research is a multiple case study of twelve countries from 2010 to 2020. Methods used in this study include Likert summative scale, a statistical and content analysis of secondary sources such as policy documents, laws, and other government acts. The results show a strong correlation between policy incentives and adoption of geothermal energy in agri-food sector. However, only 23% of growth in capacity in case countries can be explained by the levels of government support. Additionally, not all policies hold equal weight in that they are implemented on different levels of governance (global, national, and local). The study observes that between these three levels, national policies have the most correlative effect on geothermal energy adoption, while global and local policies do not seem to have significant influence. These effects vary but the overall market trends are influenced heavily by leading performers. Countries that show the most growth are – Hungary, Iceland, the Netherlands, and Türkiye. They all share strong government support on a national level, targeted policies for geothermal agri-food, and geothermal energy is economically competitive when compared to other forms of energy.
This study explores the interplay between the UNESCO status and climate governance in World Heritage cities. With climate change posing significant threats to living urban landscapes, local governments and public actors strive to implement sustainable and resilient strategies. However, complications arise when cities attain the World Heritage status, complicating climate governance practices. Qualitative research, involving interviews with key stakeholders from the Climate and Monument Protection Departments in Lübeck, Regensburg, and Bamberg, reveals a negative impact of cultural heritage on climate governance. The study contends that, when harnessed effectively, cultural heritage can contribute to the sustainability and resilience of cities in addressing climate change. It emphasises the necessity for flexibility, collaboration, and a human-centric approach, advocating for a common understanding and prioritisation of human life within climate governance. In conclusion, this research underscores the importance of viewing heritage as a dynamic component integrated into cities' climate governance strategies.
This study describes the seasonal course of denitrifying and nitrate-reducing bacteria in a dimictic mesotrophic lake (Lake Scharmützelsee, Brandenburg, Germany) within a three-year period from 2011 to 2013. The bacterial cell numbers were quantified by the fluorescence microscopy, most probable number (MPN) and PCR-dependent quantification of the chromosomal 16S rDNA and of the nirS and nirK gene copy number. The highest seasonal differences (up to three orders of magnitudes) have been measured usingMPNin the epilimnion. This variation was not reflected by PCR-dependent approaches or direct microscopical enumeration. At adverse conditions (low temperature and/or low nitrate concentrations), the differences between MPN and gene copy numbers increased by up to five orders of magnitudes and decreased to one magnitude at favourable environmental conditions. These results can be explained best by an increasing ratio of viable but not cultivable (VBNC) cells or dead cells at impairing conditions. In the hypolimnion, the courses of MPN and nir gene copy numbers were similar. This can be explained by a higher feeding pressure and therefore smaller amounts of dormant cells. In the pelagial in general, the total cell numbers enumerated by either microscopical or molecular approaches were similar. In the sediment, more than 99% of the DNA was obviously not related to viable bacteria but was rather DNA in dead cells or adsorbed to particle surfaces.
Salvaging Buildings : reclaiming a livelihood from the excesses of Istanbul's mass urbanization
(2023)
Turkey’s demolition waste management is, to a great extent, dependent on çıkmacıs (reclaimers) who salvage condemned buildings for raw materials and architectural elements. Its urbanization history is full of key moments marked by building demolitions, which became a necessary material resource for informal urbanization. As early as the 1970s, the çıkmacıs helped the gecekondus [squatter houses] by supplying second-hand building materials and construction loans. They managed to turn a lack of infrastructure into an advantage and remain very adaptable to the ever-changing conditions of neo-liberalized urbanization. They depend on solidarity networks and other informal resources. Assemblage thinking helps to redefine the concept of informality, understand the relational dynamics between various actors, and focus on the agency of materials. The empirical data gained from ‘follow the thing’ ethnographic research in Turkey and Georgia reveals the double lives of çıkmacıs who move between village and city. Additionally, by following the example of a reclaimed window frame’s journey from Istanbul to Tbilisi, we can more clearly see the second-hand trade network in the context of urbanization and incremental architecture. In the context of waste’s materiality, the empirical part of the research shows the symbiotic relationship between çıkmacıs and the discarded demolition materials.
High-resolution imaging of buried metal interconnect structures in advanced microelectronic products with full-field X-ray microscopy is demonstrated in the hard X-ray regime, i.e., at photon energies > 10 keV. The combination of two multilayer optics—a side-by-side Montel (or nested Kirkpatrick–Baez) condenser optic and a high aspect-ratio multilayer Laue lens—results in an asymmetric optical path in the transmission X-ray microscope. This optics arrangement allows the imaging of 3D nanostructures in opaque objects at a photon energy of 24.2 keV (In-Kα X-ray line). Using a Siemens star test pattern with a minimal feature size of 150 nm, it was proven that features < 150 nm can be resolved. In-Kα radiation is generated from a Ga-In alloy target using a laboratory X-ray source that employs the liquid-metal-jet technology. Since the penetration depth of X-rays into the samples is significantly larger compared to 8 keV photons used in state-of-the-art laboratory X-ray microscopes (Cu-Kα radiation), 3D-nanopattered materials and structures can be imaged nondestructively in mm to cm thick samples. This means that destructive de-processing, thinning or cross-sectioning of the samples are not needed for the visualization of interconnect structures in microelectronic products manufactured using advanced packaging technologies. The application of laboratory transmission X-ray microscopy in the hard X-ray regime is demonstrated for Cu/Cu6Sn5/Cu microbump interconnects fabricated using solid–liquid interdiffusion (SLID) bonding.
Comparing hybrid urbanisms in the global south : water delivery configurations in Peru and Ghana
(2023)
Urban development processes in the Global South (and North) are often described as characterized by formal and informal practices of different actors and their respective material realities. In critical urban studies, the disposition for this binary conception of formal and informal urbanisms has been discussed for many years. To a certain extent, these sometimes align rather problematically with contrasting notions of the “structural” versus the “everyday.” In this article, we explore an understanding of formal and informal urban practices (and respectively “structure” and “everyday”) as always interrelated, and we develop a methodology for a comparative examination of such hybrid urbanisms. In doing so, we address a missing link in the surging theoretical debate on comparative/southern urbanisms, which has rarely been substantiated by methodological explorations. The adapted concept of “delivery configurations” combines analyses of actor networks, material realities, rules and regulations, discourses, and heterogenous arrays of urban practices of negotiating these. However, bringing together local particularities and structural commonalities and exploring their interrelation only provides a basis for understanding case‐specific complexities. We argue that embedding the analysis in a multi‐scalar comparative framework can further its analytical rather than descriptive attributes and provide deeper insights into issues such as social inequality. To illustrate our methodological contribution, we provide first insights from a comparative research
project of water delivery in different neighbourhoods in the secondary cities of Sunyani (Ghana) and Arequipa (Peru). We highlight the practical challenges of comparing diverse urban contexts and examining the rather complex relationships between infrastructure delivery, urban development, and social inequality.
Biomass and bioenergy perspectives of a coal region : status quo, potential and scenarios in Lusatia
(2023)
Coal has been one of the main fuels used in Europe. Its decreasing role due to the ongoing transformation of the energy system will create significant socio-economic challenges. The switch into renewable energy systems could be an alternative to maintain jobs and economic activities within the affected regions. Biomass use and bioenergy can play an important role in the energy transition. Instead of energy crops, forest and agricultural residues should be used as biogenic energy sources in the future to avoid impacts on land use and food security. The main objective of this article is to investigate the biomass potential of a coal region and to provide scenarios for the future development of bioenergy production. Due to the changing framework conditions and, as a result, the different biomass focuses, previous bioenergy potential estimates must be reviewed. The methods for determining the potential of biomass for energy production was used for Lusatia (in German: Lausitz), the second largest coal region in Germany. These methods can also be applied in other regions. As a first step, the regional status quo assessment of cultivated areas and yields had decisive relevance for calculating biomass potential ranges. In a second step, the current bioenergy facilities in the region were identified, with a focus on power and heat production. The third step was the estimation of future regional bioenergy use. Therefore, the regional potential was gathered with the generally supra-regional framework conditions. For this purpose, national scenario studies were used, which contain the relevant target values and framework conditions. Two scenarios were developed for future bioenergy estimations: a conservative path based on the current policies and a progressive path, derived from the goal of climate neutrality by 2045. The results show a qualitative comparison among both scenarios and the previously determined potential ranges. Bioenergy can probably contribute to achieving climate neutrality with an increase in wood-fired systems, while agricultural bioenergy potential is likely to decline. In the discussion section, however, the uncertainty of these results is pointed out, as future use of bioenergy will be heavily influenced by the regulatory framework, competition with material use and the influences of climate change.
The Iberian Peninsula comprises one of the largest boundaries between Mediterranean and Eurosiberian vegetation, known as sub-Mediterranean zone. This ecotone hosts many unique plant species and communities and constitutes the low-latitude (warm) margin of numerous central European species which co-occur with Mediterranean vegetation. Two of the main species found in this region are the Eurosiberian European beech (Fagus sylvatica L.) and the Mediterranean Pyrenean oak (Quercus pyrenaica Willd.). It remains unclear how the different physiological and adaptive strategies of these two species reflect their niche partitioning within a sub-Mediterranean community and to what extent phenotypic variation (intraspecific variability) is driving niche partitioning across Eurosiberian and Mediterranean species. We quantified functional niche partitioning, based on the n-dimensional hypervolume to nine traits related to resource acquisition strategies (leaf, stem and root) plus relative growth rate as an additional whole-plant trait, and the environmental niche similarity between Pyrenean oak and European beech. Further, we analyzed the degree of phenotypic variation of both target species and its relationship with relative growth rates (RGR) and environmental conditions. Plant recruitment was measured for both target species as a proxy for the average fitness. Species’ functional space was highly segregated (13.09% overlap), mainly due to differences in niche breadth (59.7%) rather than niche replacement (25.6%), and beech showed higher trait variability, i.e., had larger functional space. However, both species shared the environmental space, i.e., environmental niches were overlapped. Most plant traits were not related to abiotic variables or RGR, neither did RGR to plant traits. Both target species share similar environmental space, however, show notably different functional resource-use strategies, promoting a high complementarity that contributes to maintaining a high functionality in sub-Mediterranean ecosystems. Therefore, we propose that conservation efforts be oriented to preserve both species in these habitats to maximize ecosystem functionality and resilience.
Linking functional composition moments of the sub-mediterranean ecotone with environmental drivers
(2023)
Functional trait-based approaches are extensively applied to the study of mechanisms governing community assembly along environmental gradients. These approaches have been classically based on studying differences in mean values among species, but there is increasing recognition that alternative metrics of trait distributions should be considered to decipher the mechanisms determining community assembly and species coexistence. Under this framework, the main aim of this study is to unravel the effects of environmental conditions as drivers of plant community assembly in sub-Mediterranean ecotones.
We set 60 plots in six plant communities of a sub-Mediterranean forest in Central Spain, and measured key above- and belowground functional traits in 411 individuals belonging to 19 species, along with abiotic variables. We calculated community-weighted mean (CWM), skewness (CWS) and kurtosis (CWK) of three plant dimensions, and used maximum likelihood techniques to analyze how variation in these functional community traits was driven by abiotic factors. Additionally, we estimated the relative contribution of intraspecific trait variability and species turnover to variation in CWM. The first three axes of variation of the principal component analyses were related to three main plant ecological dimensions: Leaf Economics Spectrum, Root Economics Spectrum and plant hydraulic architecture, respectively. Type of community was the most important factor determining differences in the functional structure among communities, as compared to the role of abiotic variables. We found strong differences among communities in their CWMs in line with their biogeographic origin (Eurosiberian vs Mediterranean), while differences in CWS and CWK indicate different trends in the functional structure among communities and the coexistence of different functional strategies, respectively. Moreover, changes in functional composition were primarily due to intraspecific variability. We observed a high number of strategies in the forest with the different communities spreading along the acquisitive-conservative axis of resource-use, partly matching their Eurosiberian-Mediterranean nature, respectively. Intraspecific trait variability, rather than species turnover, stood as the most relevant factor when analyzing functional changes and assembly patterns among communities. Altogether, our data support the notion that ecotones are ecosystems where relatively minor environmental shifts may result in changes in plant and functional composition.
The material authenticity of cultural heritage has been questioned by societies in which the modern paradigm of conservation has not developed from within the native culture. This paper examines the philosophical and practical traditions in Iran regarding the materiality and authenticity of past structures. By reviewing the emergence of the Western conservation paradigm in Iran, this paper highlights two key factors: the rapidness of this paradigm shift and the remarkable contradiction between the new and old paradigms. By borrowing the Deleuzo-Guattarian concept of a ‘body without organs’ (BwO), this paper problematises the rapidness and radicality of the paradigm shift in Iran. It suggests exploring the under-investigated possibilities between the pre-modern and modern paradigms to address the gap between native circumstances and Western standards.
Urban heritage planning in Tehran and beyond : sequences of disrupted spatial-discursive assemblages
(2023)
Despite the impact of ideological rigidity, the primary challenge of heritage planning in Tehran and beyond lies not in the dominance of an inflexible Authorized Heritage Discourse, but rather in the absence of stable spatial-discursive and administrative structures. Solmaz Yadollahi maps the historical trajectory of conservation and urban heritage planning in Iran, depicting a discursive-spatial assemblage that tends to knock down its accumulated resources. This is in line with Katouzian's portrayal of Iran as a pick-axe society. Residing within this society, the studied assemblage strives to deconstruct the prevailing structures and usher in a fresh one, paradoxically perpetuating the very cycle it seeks to escape.
Morphological and optical properties of a multilayer film (CAZO/CZAO/ZACO) prepared by spin-coating method and deposited on a glass substrate were evaluated. The study was initially carried out for each layer, individually and then as a multilayer subsequently. Structural properties using X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), infrared spectra (IR) and X-ray photoelectron Spectroscopy (XPS) showed the presence of three phases of zinc, copper and silver oxides at different levels. The CZAO sample observed with scanning electron microscope (SEM) showed an excellent porous surface with a large deformation in the multilayer configuration. Doping with zinc and copper in the silver crystal lattice improved the crystal structure and reduced the optical energy gap, thus increasing the optical absorbance and refractive index. The dielectric constants and showed an increase in the optical polarization values for lower photonic energies. The maximum degradation rate for photocatalysts of methylene blue was 89 % for a 5-h exposure period with CAZO/CZAO/ZACO while it reached 71 % for the CZAO sample during the same time period. The sensitivity of samples to light proved that the presence of ultraviolet radiation increases the number of holes trapped by oxygen ions and causes more free electrons and contribute to a better production of photocurrent than in darkness.
A contribution to the online monitoring of partial discharges in high-voltage grid components
(2024)
Increasing utilization of HV power cable lines, and particularly the advent of long HVDC underground links, results in the need to sensitively monitor their condition, such as by tracking the emergence and development of partial discharges. This study demonstrates that existing solutions are poorly suited to the case of HVDC lines, and that a new, more sophisticated monitoring system needs to address a wide array of diverse problems. First of all, the overview of the task and main functional blocks of the monitoring system is given. Following this, selected blocks are subject to detailed examination in subsequent chapters.
The first of these blocks, a high-frequency current transformer (HFCT), is responsible for capturing the signal in the power line and transferring it to the electronics. This component receives in-depth coverage: general design considerations, computation of leakage inductance, operation in presence of a power current, resonant behavior, balanced design. Particular attention is given to the application of Finite Element Analysis (FEA) in relation to the HFCT, however, the demonstrated techniques can also be applied to other magnetic devices. Last section of the chapter presents various stages of development, experimental setups, prototypes, and the final device which has been put into series production.
The next block addresses extraction of signals from noise. A literature analysis is conducted concerning noise suppression in partial discharge recordings, and the application of the signal separation approach based on Linear Predictive Coding is shown.
In the section on localization, examples illustrating problems encountered during the development of a partial discharge localization algorithm are presented.
In the chapter devoted to laboratory tests, various auxiliary experiments conducted during the system's development are compiled, where some of them are: Time Domain Reflectometry (TDR) TDR-based line characterization, estimation of monitoring sensitivity, measurement of the cable attenuation and reflection coefficients of the accessories.
In the final chapter – field tests – the installation of the system on a 110 kV line and the measured transfer function are demonstrated.
Plenty of semiconductor devices are developed to operate with private data. To guarantee data privacy cryptographic algorithms are used, where the secrecy is based on the used keys. Theoretically, the cryptographic algorithms using keys with recommended lengths are secure. The issue is that a potential attacker can steal the devices and attack in a lab. Physical attacks are usually aimed to perturb normal operation of a device and to extract cryptographic keys, e.g. by means of fault injection (FI). One class of FI attacks exploits the sensitivity of semiconductor devices to light and are performed using a laser as the light source.
This work investigates the sensitivity of different logic and memory cells to optical Fault Injection attacks. Front-side attacks against cells manufactured in different IHP technologies were performed using two different red lasers controlled by Riscure software. To reach the repeatability of the experimental results and to increase the comparability of the results with attack results published in literature the setup parameters as well as setting parameters of the Riscure software were experimentally evaluated. Attacks were performed against inverter, NAND, NOR, flip-flop cells from standard libraries, radiation-hard flip-flops based on Junction Isolated Common Gate technique, radiation-tolerant Triple Modular Redundancy registers as well as non-volatile Resistive Random Access Memory (RRAM) cells. The results of attacks against volatile circuits were successful transient bit-set and bit-reset as well permanent stuck-at faults. The results of attacks against RRAM cells were successful in the sense that manipulation of all RRAM logic states was feasible. The faults injected during the performed experiments were repeatable and reproducible.
The goal of this work was not only to achieve successful FI but also to determine cell area(s) sensitive to laser illumination. Knowledge about areas sensitive to laser illumination can be used by designers to implement corresponding countermeasure(s) at the initial stage of chip development and is the necessary step to design appropriate countermeasures. For example, metal fillers can be applied as optical obstacles reducing the success of front-side FI attacks, i.e. as a possible low-cost countermeasure. Based on the knowledge of the sensitive cell areas, the placement of the metal fillers can be automated in the future, i.e. the findings given in the work can serve as a basis for a methodology development for improving resistance against optical FI attacks at the initial stage of chip development. Such methodology can be adapted for each chip manufacturing technology.