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Reaching population immunity against COVID-19 is proving difficult even in countries with high vaccination levels. We demonstrate that this in part is due to heterogeneity and stochasticity resulting from community-specific human-human interaction and infection networks. We address this challenge by community-specific simulation of adaptive strategies. Analyzing the predicted effect of vaccination into an ongoing COVID-19 outbreak, we find that adaptive combinations of targeted vaccination and non-pharmaceutical interventions (NPIs) are required to reach population immunity. Importantly, the threshold for population immunity is not a unique number but strategy and community dependent. Furthermore, the dynamics of COVID-19 outbreaks is highly community-specific: in some communities vaccinating highly interactive people diminishes the risk for an infection wave, while vaccinating the elderly reduces fatalities when vaccinations are low due to supply or hesitancy. Similarly, while risk groups should be vaccinated first to minimize fatalities, optimality branching is observed with increasing population immunity. Bimodality emerges as the infection network gains complexity over time, which entails that NPIs generally need to be longer and stricter. Thus, we analyze and quantify the requirement for NPIs dependent on the chosen vaccination strategy. Our simulation platform can process and analyze dynamic COVID-19 epidemiological situations in diverse communities world-wide to predict pathways to population immunity even with limited vaccination.

CO2 is a promising gas for replacement of SF6 in high voltage circuit breakers. The electric breakdown in CO2 and mixtures with C2F4 from PTFE nozzles is, however, still not fully understood. To understand the electric breakdown in CO2 and mixtures with C2F4 from PTFE nozzles fundamental parameters like the temperature and pressure dependence of critical electric fields are needed. Data on critical fields is usually available based on simulations only and experimental validation is lacking so far. Our present contribution aims to close this gap and presents experiments where the breakdown fields in uniform and weakly non-uniform electric fields are determined at various temperatures and pressures. The gas temperatures were estimated from measurements with pyrometers. The results are compared to theoretical predictions.

In this paper, the results of the experiments performed on electrical breakdown in CO2 and CO2-O2 mixtures in weakly and strongly non-uniform fields generated with impulse (2/160) µs, AC and DC waveforms are presented. In weakly non-uniform fields, the electrical breakdown field approximately follows 11 kV/(cm bar) when stressed with both AC and DC (positive and negative) waveforms. For positive impulse, the breakdown voltage is higher and the time lag to breakdown is scattered, indicating a lack of starting electrons from CO2 gas. Furthermore, the breakdown strength of CO2 - O2 (10-30)% mixtures is investigated. On application of negative polarity impulse, the breakdown strength is significantly higher than positive impulse in the measured pressure range of 0.3-0.7 MPa in strongly non-uniform fields, contrary to that seen during breakdown in weakly non-uniform fields. Breakdown voltage for negative impulse is further enhanced in a mixture of CO2-O2 (80-20)%., IEEE Transactions on Dielectrics and Electrical Insulation, 28 (1), ISSN:1070-9878, ISSN:1558-4135

Interactions between humans cause transmission of SARS-CoV-2. We demonstrate that heterogeneity in human-human interactions give rise to non-linear infection networks that gain complexity with time. Consequently, targeted vaccination strategies are challenged as such effects are not accurately captured by epidemiological models assuming homogeneous mixing. With vaccines being prepared for global deployment determining optimality for swiftly reaching population level immunity in heterogeneous local communities world-wide is critical. We introduce a model that predicts the effect of vaccination into an ongoing COVID-19 outbreak using precision simulation of human-human interaction and infection networks. We show that simulations incorporating non-linear network complexity and local heterogeneity can enable governance with performance-quantified vaccination strategies. Vaccinating highly interactive people diminishes the risk for an infection wave, while vaccinating the elderly reduces fatalities at low population level immunity. Interestingly, a combined strategy is not better due to non-linear effects. While risk groups should be vaccinated first to minimize fatalities, significant optimality branching is observed with increasing population level immunity. Importantly, we demonstrate that regardless of immunization strategy non-pharmaceutical interventions are required to prevent ICU overload and breakdown of healthcare systems. The approach, adaptable in real-time and applicable to other viruses, provides a highly valuable platform for the current and future pandemics.

Reaching population immunity against COVID-19 is proving difficult even in countries with high vaccination levels. We demonstrate that this in part is due to heterogeneity and stochasticity resulting from community-specific human-human interaction and infection networks. We address this challenge by community-specific simulation of adaptive strategies. Analyzing the predicted effect of vaccination into an ongoing COVID-19 outbreak, we find that adaptive combinations of targeted vaccination and non-pharmaceutical interventions (NPIs) are required to reach population immunity. Importantly, the threshold for population immunity is not a unique number but strategy and community dependent. Furthermore, the dynamics of COVID-19 outbreaks is highly community-specific: in some communities vaccinating highly interactive people diminishes the risk for an infection wave, while vaccinating the elderly reduces fatalities when vaccinations are low due to supply or hesitancy. Similarly, while risk groups should be vaccinated first to minimize fatalities, optimality branching is observed with increasing population immunity. Bimodality emerges as the infection network gains complexity over time, which entails that NPIs generally need to be longer and stricter. Thus, we analyze and quantify the requirement for NPIs dependent on the chosen vaccination strategy. We validate our simulation platform on real-world epidemiological data and demonstrate that it can predict pathways to population immunity for diverse communities world-wide challenged by limited vaccination.

According to the WHO, cancer is the second most common cause of death worldwide. The social and economic damage caused by cancer is high and rising. In Europe, the annual direct medical expenses alone amount to more than €129 billion. This results in an urgent need for new and sustainable therapeutics, which has currently not been met by the pharmaceutical industry; only 3.4% of cancer drugs entering Phase I clinical trials get to market. Phosphorylation sites are parts of the core machinery of kinase signaling networks, which are known to be dysfunctional in all types of cancer. Indeed, kinases are the second most common drug target yet. However, these inhibitors block all functions of a protein, and they commonly lead to the development of resistance and increased toxicity. To facilitate global and mechanistic modeling of cancer and clinically relevant cell signaling networks, the community will have to develop sophisticated data-driven deep-learning and mechanistic computational models that generate in silico probabilistic predictions of molecular signaling network rearrangements causally implicated in cancer.

Re-opening societies and economies across the globe following the initial wave of the severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) pandemic requires scientifically-guided decision processes and policy development. Public health authorities now consider it highly likely that transmission of SARS-CoV-2 and COVID-19 will follow a pattern of seasonal circulation globally. To guide mitigation strategies and tactics in a location-specific manner, accurate simulation of prolonged or intermittent patterns of social/physical distancing is required in order to prevent healthcare systems and communities from collapsing. It is equally important to capture the stochastic appearance of individual transmission events. Traditional epidemiological/statistical models cannot make predictions in a geospatial temporal manner based on human individuals in a community. Thus, the challenge is to conduct spatio-temporal simulations of transmission chains with real-world geospatial and georeferenced information of the dynamics of the disease and the effect of different mitigation strategies such as isolation of infected individuals or location closures. Here, we present a stochastic, geospatially referenced and demography-specific agent-based model with agents representing human beings and include information on age, household composition, daily occupation and schedule, risk factors, and other relevant properties. Physical encounters between humans are modeled in a time-dependent georeferenced network of the population. The model (GERDA-1) can predict infection dynamics under normal conditions and test the effect of different mitigation scenarios such as school closures, reduced social contacts as well as closure or reopening of public/work spaces. Specifically, it also includes the fate and influence of health care workers and their access to protective gear. Key predictions so far entail: (i) the effect of specific groups on the spreading, specifically that children in school contribute substantially to distribution. (ii) the result of reopening society depends crucially on how strict the measures have been during lock-down. (iii) the outcome of reopening is a stochastic process - in the majority of cases, we must expect a second wave, in some cases not. To the best of our best knowledge, the GERDA-1 model is the first model able to predict a bimodal behavior of SARS-Cov-2 infection dynamics. Given the criticality of the global situation, informing the scientific community, decision makers and the general public seems prudent. Therefore, we here provide a pre-print of the GERDA-1 model together with a first set of predictions and analyses as work in progress.

The electric breakdown at single and multiple protrusions in SF6 and CO2 is investigated at 0.4 and 0.6 MPa, respectively. Additionally, the breakdown fields at rough surfaces of two different areas were determined. From the measurements, breakdown probability distributions for single protrusions were determined and fitted by Weibull distributions. This allowed the determination of statistical enlargement laws for the 50% breakdown probability fields E50. Such enlargement laws describe, for example, the scaling of breakdown field with electrode area or number of protrusions. The predictions were compared to the experimental data, and both agreement and discrepancies were observed depending on polarity and number of protrusions and gas. Discharge predictions including first electron, streamer inception and crossing, as well as leader propagation, gave further insight to this. It was found that predictions from enlargement laws based on statistical processes may not describe the measured breakdown fields well and that relevant physical breakdown criteria must also be considered.

The breakdown in synthetic air at 100 kPa in rod-plane arrangements at 50 mm gap and in atmospheric air in the range of a few centimeters to some ten centimeters was investigated at positive polarity. Different shapes of the rods (spherical and sharp cut) were used to investigate the influence of the details of the electric field at the tips. Optical diagnostics using an image intensifier and a photomultiplier tube was applied to determine the relevant breakdown mechanisms. Streamer crossing was observed at typical average fields of about 4 to 5 kV/cm. Breakdown occurred at significantly higher fields via leader propagation or streamer-to-spark transition. The experimental results are compared to a simple 1D leader model and to breakdown data from literature. A reasonable description of experimental values by the leader model is seen.

Gene expression is a stochastic process and its appropriate regulation is critical for cell cycle progression. Cellular stress response necessitates expression reprogramming and cell cycle arrest. While previous studies are mostly based on bulk experiments influenced by synchronization effects or lack temporal distribution, time-resolved methods on single cells are needed to understand eukaryotic cell cycle in context of noisy gene expression and external perturbations. Using smFISH, microscopy and morphological markers, we monitored mRNA abundances over cell cycle phases and calculated transcriptional noise for SIC1, CLN2, and CLB5, the main G1/S transition regulators in budding yeast. We employed mathematical modeling for in silico synchronization and for derivation of time-courses from single cell data. This approach disclosed detailed quantitative insights into transcriptional regulation with and without stress, not available from bulk experiments before. First, besides the main peak in G1 we found an upshift of CLN2 and CLB5 expression in late mitosis. Second, all three genes showed basal expression throughout cell cycle enlightening that transcription is not divided in on and off but rather in high and low phases. Finally, exposing cells to osmotic stress revealed different periods of transcriptional inhibition for CLN2 and CLB5 and the impact of stress on cell cycle phase duration. Combining experimental and computational approaches allowed us to precisely assess cell cycle progression timing, as well as gene expression dynamics., Single-cell approach dissects noisy cell cycle transcription Single-molecule time-resolved mRNA quantification revealed long-term regulation of transcription and cell cycle progression upon osmotic stress. A team led by Edda Klipp at Humboldt-Universität zu Berlin, Germany, combined smRNA-FISH microscopy, genetic and morphological markers and stochastic modeling to monitor mRNA dynamics and related noise levels throughout cell cycle for SIC1, CLN2, and CLB5, main G1/S regulators in budding yeast. All genes were present throughout cell cycle enlightening that transcription is not divided in on and off but rather in high and low phases. Osmotic stress induced distinct periods of inhibition for CLN2 and CLB5, and long-term impact on cell cycle phase progression. This approach provided insights in transcription regulation unavailable with bulk experiments and chemical synchronization. Future research may address whether these patterns are general to other eukaryotic cell cycle regulators.

The breakdown electric field strength in synthetic air, CO 2 , a mixture of CO 2 and O 2 , and CF 4 was investigated under conditions relevant for high voltage insulation systems, specifically, in nearly uniform fields and using electrodes with technical surfaces. The results show a saturation of the breakdown electric field strength above 2 MPa; this effect can be explained by streamer inception calculations. The lowest saturation breakdown electric field strengths are similar for the different gases and are in the range of 200 to 300 kV/cm. There is no change in the breakdown electric field strength if the gas becomes supercritical. This indicates that particle number density and the surface structure is the main controlling parameter for the breakdown in the investigated parameter range.

The available knowledge of state-of-the-art of SF6 alternative gases in switching applications was collected and evaluated in an initiative of the Current Zero Club [1] together with CIGRE. The present contribution summarizes the main results of this activity and will also include the latest trends. The main properties and switching performance of new gases are compared to SF6. The most promising new gases are at the moment perfluoroketones and perfluoronitriles. Due to the high boiling point of these gases, in HV applications mixtures with CO2 are used. For MV insulation perfluoroketones are mixed with air, but also other combinations might be possible. The dielectric and switching performance of the mixtures, with mixing ratios that allow sufficiently low operating temperatures, is reported to be only slightly below SF6. Minor design changes or de-rating of switchgear are therefore necessary. Differences between the gas mixtures are mainly in the boiling point and the GWP, Plasma Physics and Technology Journal, 4 (1), ISSN:2336-2634

Martin Seeger wächst mit einer Zerebralparese auf. Nach vielen Jahren, in denen ihn Bobath- und Vojta-Therapien begleiteten, schließt er sich im Alter von 45 Jahren einer inklusiven Klettergruppe an. Große Fortschritte beim Klettern und ein konsequent angewendetes Stehtraining geben ihm neue Perspektiven. Ein Erfahrungsbericht.

The research on high voltage circuit breakers using SF6 is addressed. The current state of the art in this field is shortly reviewed and future research directions are discussed. These are mainly the radiative energy transport, the understanding and description of ablation processes at the nozzle and contact surfaces, the influence of such vapors on pressure build up and interruption capability, electric breakdown processes, departures from equilibrium, turbulence and the importance of magnetic fields and 3D modelling.

Recent results of experimental and theoretical investigations on current interruption processes are presented with a focus on SF6 high voltage circuit breakers. Various aspects of thermal interruption at the zero crossing of the current are shown, including the scatter and the distribution of arc voltage shortly before CZ and the role of turbulence. The thermal interruption capability of air and CO2 are compared to that of SF6. Investigations on the dielectric recovery are shown for SF6 and CO2. The breakdown voltage during the dielectric recovery can be described by simple streamer and leader inception models. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Recently we have seen an increasing number of publications, mostly of an ethnographic nature, describing and discussing the significant religious roles and achievements of Thai Buddhist women, not only in the field of Buddhist education, and with regard to their monastic roles, but also in terms of their roles as accomplished Buddhist practitioners. This paper examines the changes occurring in the status and position of women in Thai Buddhist practice. In this regard I focus on the analysis of one of the first widely acknowledged female saints of modern Thai Buddhism: Khun Mae Bunruean Tongbuntoem (1895–1964). Khun Mae Bunruean has obtained her increasing reputation through the advanced meditative achievements which her followers believe she possessed. I use hagiographical accounts of her as a focal point to unravel and examine Thai beliefs in relation to female sainthood in present-day Thai Buddhism. This is done by discussing gendered hagiographical writing against the background of relevant canonical and post-canonical Pali texts that have exerted authority in religious discourses on gender by informing and nurturing Thai religious value systems. This textual research is complemented by the ethnographic examination of Thai Buddhist beliefs and venerational practices which cannot be found in authoritative Pali texts but which still play a significant role in the understanding of the particularities of female saints in modern Thai Buddhism. I do not confine myself to hagiographical accounts and venerational practices directly linked to gender, but also devote some attention to other conspicuous aspects, elements, and expressions of Mae Bunruean's sainthood and her veneration.

The domain name system (DNS) is often abused by criminals as resilient infrastructure for their network architecture. Examples for malicious activities based on these networks comprise e.g. phishing, click fraud, spam, command and control structure of botnets. Most of the proposed detection methods rely on machine learning based on complex feature sets which require a considerable computational power. This paper investigates the approach of passively monitoring and analyzing DNS traffic in a time efficient manner based on machine learning on a reduced and robust feature set. For the evaluation the full DNS data stream of a regional ISP is used. To enhance the amount of traffic that can be labeled for the training process and reduce the number of false negatives in the case study, this is combined with a semi-manual labeling approach which addresses domains created by Domain-Generation-Algorithms (DGAs). That allows also medium sized, regional service providers to train classifiers with typical DNS traffic and to deploy systems based on the approach proposed here, in the network of organizations as an alternative to cloud services. The evaluation shows that this approach is feasible and prototypes are already deployed. Hence this approach can serve as an important aspect of the internal risk management of organizations.

Both Thai and Western academia have recently paid increasing attention to the changing roles of Thai Buddhist women. Still conspicuously missing, however, are more in-depth studies of female Buddhi...

Thai Buddhism is characterised by a complex polymorphism that has become manifest in the plurality of religious movements and cults. There exists an enormous variety of belief systems and religious practices that are based on widely differing interpretations of religious texts or other sources of normative and formative authority. These systems and practices are far from static, but changing with a similar pace as current Thai society as a whole does. This religious plurality and change can also readily be perceived in the socio-religious roles of Thai Buddhist women. With this paper, I intend to contribute to the existing body of academic literature on the changing roles of Thai Buddhist women, by reporting on the lives of a sample of outstanding Buddhist women, who excel in various realms. While doing so, I will show the significance of their lives and work in the context of current Thai Buddhism.

In this paper I investigate a number of public intellectual debates in current Thai Theravada Buddhism that are related to several fundamental questions regarding the meaning and function of the Pali canon. The focal point of this investigation will be debates in which the Thai scholar monk Phra Payutto (b. 1939) has been playing a significant role. In these debates, the Pali canon is regarded as a central text endowed with special normative and formative authority. I will look at contestations that concern Theravada-ness and, at the same time, and inextricably linked with this, at concepts of demarcation to systems of religious beliefs and practices that are believed to be ‘outside’ Theravada. This, of course, engages the question of inclusivism, exclusivism and pluralism within Theravada. In so doing, I explore and posit concepts on the meanings and functions of the Pali canon that position it either as the or an authoritative reference.

Understanding the dynamic processes governing gas circuit breaker physics is crucial in order to continue to improve short-circuit current interruption performance. In this paper, we study a single arc discharge both using measurements and 3-D computational fluid dynamics simulations. The primary quantity analyzed is the pressure in the heating volume created by radiative ablation of the Polytetrafluoroethylene nozzles surrounding the arc. We use cross-correlation functions to investigate the behavior of pressure waves in the SF6 gas, especially those induced at flow reversal where the gas flow between the arc zone and heating volume changes direction.

In Thai Buddhism, a high number of examples show that during the last 20 years or so the triangular interrelationship between hermeneutics, canonical authenticity and authority has been—more or less consciously—the subject of numerous, often very fervent debates. This has made clear the importance of the Pāli canon as a centre of reference for normative and formative authority in Thai society. Also, during these debates the conservatism of Thai Theravāda, and thereby its identity, has been challenged in various ways, e.g. by Western influenced text-critical or intertextual approaches, by reference to superior religious insight and by requests for feminist interpretations of the Pāli canon. At the same time, however, and in response to these challenges, the rationale for Thai Theravāda's conservatism and identity have become very clearly articulated, to an extent that has arguably never happened before in Thai history. By looking at some of the debates in which the foremost Thai Buddhist thinker and schola...

A model is discussed, which allows in an easy way to perform electric field simulations in unipolar space charge controlled dielectric media with the finite element method. The approach is appropriate for a variety of different devices in electrical engineering, containing solid, liquid, or gaseous insulators. The main issue concerns the boundary condition at the charge injecting contacts, including ohmic contacts (leading to space charge limited currents) as well as contacts with a finite threshold field for injection (e.g., by Corona onset in gas). The model naturally contains the high-current limit, where the current is injection dominated, i.e., given by the saturation current of the contact, and the capacitive field is restored. Results for a few examples are presented, in order to validate the method by comparison with analytical results, and in order to illustrate its usefulness for applications. In particular, for gaseous insulation various steady state and transient field distributions are calculated. With this approach it is easily possible to investigate the effect of convective currents as well as the charging of dielectrics surfaces.

Journal of Physics D: Applied Physics, 48 (24), ISSN:0022-3727, ISSN:1361-6463

This paper reports on the use of computational fluid dynamic (CFD) simulations to predict the interruption behaviour of high-voltage circuit breakers (HV-CB) using the self-blast principle. Two different levels of accuracy of the arc model are proven to be sufficiently accurate for simulating the high-current phase and the period around current zero (CZ). For the high-current phase, a simplified equivalent model of the arc is implemented to predict the pressure build-up, and even more important to accurately trace the hot gas from the arcing zone into the exhausts and the heating volume. A detailed analysis of the gas mixing in the heating volume for different arcing times and current amplitudes showed the optimum geometrical design of the heating volume. For the CZ phase, a more detailed arc model is needed including the effects of ohmic heating, radiative energy transfer, and turbulent cooling fully resolved in space and time. The validation with experiments was done and shows good agreement which justifies the use of the implemented model. With it, scaling laws varying only one parameter at a time (pressure and applied current slope) were derived and confirm previously found empirical laws. This is of particular interest, as it is very difficult to derive such scaling laws from experiments where the scatter is always very large and where it is impossible to vary only one parameter at a time. The influence of the most important geometrical parameters of the nozzle on the interruption performance is shown. In addition to previous experimental indications of this, the simulation reveals that turbulent cooling on the arc edge is the main reason for the difference in interruption performance. Moreover, the exact spatio-temporal build-up of arc resistance and with it the detailed understanding of the arc interruption process is possible and shown here for the first time. These simulations enable us to predict HV-CB performance and to minimise the number of development tests and are routinely used in new development projects. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The average surface ablation of poly-tetra-fluro-ethylene (PTFE) nozzles in high voltage circuit-breakers was investigated experimentally by means of the specific ablation. Experiments were done with a test device in the current and arcing time range of 2–40 kArms and 5–17 ms, respectively. This allowed determining the dependences of the specific PTFE ablation on current and arcing time. Additionally, the specific PTFE nozzle ablation in commercial high voltage circuit-breakers was analysed in a broad range of current amplitudes and arcing times. For understanding the results more in detail, experiments with a small scale test device were performed. The different experiments yielded consistent values for the PTFE ablation. The ablation depends mainly on the total arc energy. The total ablation is given by the ablation of walls surrounding the arc and by the ablation in regions where plasma from the arc cools down. Different specific ablation values can be observed for the axial blown arc mode and the ablation controlled arc mode.

The prediction and understanding of the erosion process of the Cu/W arcing contacts in high-voltage circuit breakers is important for the improvement of the breaker lifetime. The change of the contact geometry due to erosion is a main factor, which influences the lifetime. It is known that the ablation of contact material depends at least on parameters like the arcing current-amplitude, arcing time, total charge, and contact material properties. Based on experimental results, a method for an improved prediction of the erosion was derived. The experiments have been carried out in a SF6 self-blast circuit breaker test device with commercial high-voltage circuit breaker contacts at a current amplitude up to 45kA RMS and arcing time up to 17ms. From the power balance at the electrodes, the material erosion due to evaporation is calculated. The resulting erosion rates are in good agreement to the experimental results and explain that the specific erosion scales with current, polarity, and the arcing time. This indicates that erosion in this range of arcing stress occurs mainly due to evaporation of contact material and less to emission of droplets

A simple integral arc model for ablation arcs in tubes is presented. The model predicts the arc temperature in the axis, the average electrical field strength, the pressure generation and the mass ablation rate at the tube wall. The model is entirely based on first principles and does not require fit parameters. This is achieved with the help of detailed numerical arc simulations which use a combination of a radiative energy transfer code and computational fluid dynamics. This allows a physically correct and consistent averaging over the arc when deriving the integral model. New experiments for validation of the model were done. The results of the model are in satisfactory agreement with the older and new experimental data. The dependences of the predicted arc parameters are discussed for tube radii and lengths in the parameter range R = 2?8?mm and L = 40?80?mm, respectively.

The dielectric recovery of an axially blown arc in an experimental set-up based on a conventional HV circuit breaker was investigated both experimentally and theoretically. As a quenching gas, synthetic air was used. The investigated time range was from 10 µs to 10 ms after current zero (CZ). A fast rise in the dielectric strength during the first 100 µs, followed by a plateau and further rise later was observed. The dependences on the breaking current and pressure were determined. The measured dielectric recovery during the first 100 µs after CZ could be reproduced with good accuracy by computational fluid dynamics simulations. From that it could be deduced that the temperature decay in the axis does not depend sensitively on the pressure. The dielectric recovery during the first 100 µs scales therefore mainly with the filling pressure. The plateau in the breakdown characteristic is due to a hot vapour layer from the still evaporating PTFE nozzle surface. (Some figures in this article are in colour only in the electronic version)

This chapter considers how a number of Thai Buddhists have sought to explain the causes of environmental degradation and how they have responded to it by proposing a variety of different strategies informed by religious beliefs, practices and teachings. Materialistic acquisitiveness is interwoven with beliefs in the supernaturalness of nature. Phra Khru Suphajarawat pointed out that whereas formerly the motivation for environmental conservation was to a large extent based on the belief that nature is inhabited by powerful supernatural beings, only a combination of a variety of motivational factors is necessary now-a-days for the protection of the environment. Phra Payutto explains that the Buddhist 'ethics of happiness' implies that environmentalist action and restraint in consumption are to be practised automatically, naturally and wholeheartedly. In many of his works, Phra Payutto seeks to rectify 'narrowed' Thai perceptions of karma that focuses solely on negative, past karma. Keywords: environmental protection; Phra Payutto; social karma; Thai Buddhism

CO2 is a promising gas for the replacement of SF6 in high-voltage transmission and distribution networks due to its lower environmental impact. The insulation properties of CO2 are, therefore, of great interest. For this, the properties of streamers are important, since they determine the initial discharge propagation and possibly the transition to a leader. The present experimental investigation addresses the streamer inception and propagation at ambient temperature in the pressure range 0.05–0.5 MPa at both polarities. Streamer parameters, namely the stability field, radius and velocity, were deduced in uniform and in strongly non-uniform background fields. The measured breakdown fields can then be understood by streamer propagation and streamer-to-leader transition.

In standard high voltage gas circuit breakers -important safety elements in today's power grids-, a small surface layer of polytetrafluoroethylene (PTFE) vaporizes at the high temperatures occurring in the arcing zone during the high current phase of the interruption process. This ablation continues even some hundred microseconds after the arc has been quenched and it actually changes the total gas composition as well as the temperature profile in the arcing zone. Therefore it delays the fast cooling of the arcing zone, which is necessary to prevent dielectric failures. The experimental determination of the dielectric recovery of hot air in insulating nozzles was investigated previously with focus on the substitution of SF6 (sulfur hexafluoride) in circuit breakers for future power grids. The present investigation gives a physical model for the calculation of the previously measured recovery characteristics. CFD-simulations (computational fluid dynamics) are performed for the determination of the relevant physical properties of the decaying quenching gas (density, temperature etc.). These properties serve as input parameters for the developed model. Based on the gas properties resulting from the CFD-simulations it is possible to calculate the effective ionization coefficients and thus the breakdown voltage applying the streamer criterion. Afterwards the calculated breakdown voltages are compared to the measured recovery characteristics. The comparison shows a good agreement between the measurements and the calculation.

Measurements and simulations of cold gas flows in Gas Circuit Breakers (GCB) geometries were done. The found flow patterns are related to the dielectric performance during a switching operation. A reference experiment was designed with direct pressure measurements at several positions in the nozzle-diffuser system and on the edge of the plug tip. The results show the development of minimum density regions around the edge of the plug tip. For many contact designs this is also the region of highest electric field stress and thus dielectrically weak. The measurements are compared to CFD simulations and show mostly very good agreement. The flow pattern can be quite complex, including supersonic velocities and shock fronts as well as regions of flow separation and re-attachment. An experimental sensitivity analysis was performed to study the influence of deviations from the idealized reference geometry to real circuit breakers, where deviations from e.g. perfect axis- symmetry are inevitable.

Summary form only given. The arcing zone of high voltage self-blast gas circuit breakers is challenging to diagnose directly due to the combination of temperatures in the 30,000 K range and densities of the order 1025 m-3. Instead proxy measurements are made, typically in the heating volume of the breakers. In this contribution we compare pressure measurements of the SF6 gas from two sensors to 3D computational fluid dynamics (CFD) simulations. The simulated pressure evolution is evaluated at the same position as the actual sensors are placed, so in that sense the CFD simulations can be thought of as a synthetic diagnostic. The overarcing purpose of this quantitative comparison of CFD simulations with measurements is to improve our understanding of the physics of current interruption in gas circuit breakers. The strategy has already been successfully applied to turbulence measurements in fusion plasmas. Further, questions will be generated in the case where agreement is poor between simulation and experiment. This in turn guides us as to what should be (i) modified in the simulation and/or (ii) additionally measured to answer the questions posed and thereby improve our knowledge of the physical processes.

Summary form only given. We report on experiments conducted to investigate the thermal interruption capability of high voltage self-blast gas circuit breakers. In parallel, the circuit breaker behavior is studied using computational fluid dynamics tools. It is well-known that nozzle ablation leads to systematic performance degradation. The influence of nozzle ablation on various parameters is studied as a function of the number of interruptions. Overall thermal interruption features of a test series are presented along with an analysis of the synthetic circuit. In order to study fluctuation characteristics during thermal interruption, we apply spectral analysis to our measurements of pressure in the accessible volumes of the circuit breaker, e.g. in the heating volume. We have identified pressure turbulence at frequencies above 100 kHz during the high pressure phase. A search for systematical dependencies of the fluctuations on nozzle ablation is presented. Additionally, fluctuations in the current and voltage measurements are touched upon