Filter Results
50820 results
China's urbanisation has caused city populations to grow rapidly, boosting continuous development and scaling up the construction industry more intensely. The building sector is thus a key area to consider for climate change mitigation efforts. This study initially seeks to explore the development of a green transition pathway for the Chinese building sector, informed by national and local low-carbon policies and strategies, with specific references to Beijing and Shanghai. Acknowledging that the barriers and impacts of these policies have not been explored in depth and in consideration of the multiplicity of stakeholder views, we then set out to collect stakeholders’ perspectives of implementation and consequential risks associated with the envisaged transition and with the policies aiming to promote this transition. These concerns are evaluated in a multiple-criteria group decision making approach. By focusing on the resulting most critical implementation barriers, we then outline five plausible socioeconomic scenarios, against which we simulate the impacts of the considered policy strategies on the low-carbon transition of the Chinese built environment as well the extent of their key possible negative consequences, by means of fuzzy cognitive maps.,Energy Research & Social Science, 59,
Data Types:
  • Document
At high temperatures, isotope partitioning is often assumed to proceed under equilibrium and trends in the carbon isotope composition within graphite and diamond are used to deduce the redox state of their fluid source. However, kinetic isotope fractionation modifies fluid- or melt-precipitated mineral compositions when growth rates exceed rates of diffusive mixing. As carbon self-diffusion in graphite and diamond is exceptionally slow, this fractionation should be preserved. We have hence performed time series experiments that precipitate graphitic carbon through progressive oxidization of an initially CH4-dominated fluid. Stearic acid was thermally decomposed at 800 °C and 2 kbar, yielding a reduced COH-fluid together with elemental carbon. Progressive hydrogen loss from the capsule caused CH4 to dissociate with time and elemental carbon to continuously precipitate. The newly formed C0, aggregating in globules, is constantly depleted by -6.5±0.3‰ in 13C relative to the methane, which defines a temperature dependent kinetic graphite-methane 13C/12C fractionation factor. Equilibrium fractionation would instead yield graphite heavier than the methane. In dynamic environments, kinetic isotope fractionation may control the carbon isotope composition of graphite or diamond, and, extended to nitrogen, could explain the positive correlation of δ13C and δ15N sometimes observed in coherent diamond growth zones. 13C enrichment trends in diamonds are then consistent with reduced deep fluids oxidizing upon their rise into the subcontinental lithosphere, methane constituting the main source of carbon.,Earth and Planetary Science Letters, 529,
Data Types:
  • Document
As face-to-face and ICT-mediated social interaction patterns are relevant to explain (social) travel behavior, the objective of this paper is to study comparatively the factors that influence social interaction frequency via different communication modes. The analysis is based on seven recent data collections on personal social networks from Canada, Chile, Switzerland, the Netherlands, and Japan. A multilevel-multivariate mixed model that explicitly accounts for the hierarchical nature of the data is used to jointly analyze contact frequency patterns across all samples. We show the existence of very consistent associations across samples between individual and relational characteristics and social interactions such as age, network size, distance and emotional closeness. At the same time, for other characteristics such as gender and relationship type, among others, effect patterns were less clear, differences that might be explained by intrinsic contextual characteristics as well as methodological differences among studies.
Data Types:
  • Document
The Larderello-Travale Geothermal Field in South-West Tuscany (Italy) is the oldest and among the most productive geothermal fields in the world. A new 3D model of seismic P-wave velocity (VP) of the upper crust beneath the geothermal field is derived by inverting a set of highly consistent travel-times from local-earthquakes. Results document a marked correlation of VP with previously described, high-reflectivity horizons. We also determined a low velocity body (VP ∼5 km s−1) culminating at depths of about 7 km, with estimated volume of 35–40 km3. Such low velocities are consistent with a granite at temperatures above 700 °C, thus in a partially-molten status.,Geothermics, 83,
Data Types:
  • Document
In older adults, physical activity is crucial for healthy aging and associated with numerous health indicators and outcomes. Regular assessments of physical activity can help detect early health-related changes and manage physical activity targeted interventions. The quantification of physical activity, however, is difficult as commonly used self-reported measures are biased and rather unprecise point in time measurements. Modern alternatives are commonly based on wearable technologies which are accurate but suffer from usability and compliance issues. In this study, we assessed the potential of an unobtrusive ambient-sensor based system for continuous, long-term physical activity quantification. Towards this goal, we analysed one year of longitudinal sensor- and medical-records stemming from thirteen community-dwelling old and oldest old subjects. Based on the sensor data the daily number of room-transitions as well as the raw sensor activity were calculated. We did find the number of room-transitions, and to some degree also the raw sensor activity, to capture numerous known associations of physical activity with cognitive, well-being and motor health indicators and outcomes. The results of this study indicate that such low-cost unobtrusive ambient-sensor systems can provide an adequate approximation of older adults’ overall physical activity, sufficient to capture relevant associations with health indicators and outcomes.,Scientific Reports, 9,
Data Types:
  • Document
Images captured by unmanned aerial vehicles (UAVs) and processed by structure-from-motion (SfM) photogrammetry are increasingly used in geomorphology to obtain high-resolution topography data. Conventional georeferencing using ground control points (GCPs) provides reliable positioning, but the geometrical accuracy critically depends on the number and spatial layout of the GCPs. This limits the time and cost effectiveness. Direct georeferencing of the UAV images with differential GNSS, such as PPK (post-processing kinematic), may overcome these limitations by providing accurate and directly georeferenced surveys. To investigate the positional accuracy, repeatability and reproducibility of digital surface models (DSMs) generated by a UAV–PPK–SfM workflow, we carried out multiple flight missions with two different camera–UAV systems: a small-form low-cost micro-UAV equipped with a high field of view (FOV) action camera and a professional UAV equipped with a digital single lens reflex (DSLR) camera. Our analysis showed that the PPK solution provides the same accuracy (MAE: ca. 0.02 m, RMSE: ca. 0.03 m) as the GCP method for both UAV systems. Our study demonstrated that a UAV–PPK–SfM workflow can provide consistent, repeatable 4-D data with an accuracy of a few centimeters. However, a few flights showed vertical bias and this could be corrected using one single GCP. We further evaluated different methods to estimate DSM uncertainty and show that this has a large impact on centimeter-level topographical change detection. The DSM reconstruction and surface change detection based on a DSLR and action camera were reproducible: the main difference lies in the level of detail of the surface representations. The PPK–SfM workflow in the context of 4-D Earth surface monitoring should be considered an efficient tool to monitor geomorphic processes accurately and quickly at a very high spatial and temporal resolution.,Earth Surface Dynamics, 7 (3),
Data Types:
  • Document
Methane as a fuel is becoming more and more interesting for engine applications due to ever stricter pollutant and greenhouse gas emission regulations and market requirements in both mobile and stationary applications. The use of methane enables the reduction of nitrogen oxides, soot and CO2 emissions from combustion compared to Diesel and gasoline and has the potential to increase efficiency through increased knock resistance. Biogenic sources and the conversion of excess electricity from renewable sources into methane in power-to-gas plants can further improve the CO2 balance and give methane a long-term perspective. An additional increase in efficiency and a further reduction in the knock tendency as well as a minimization of nitrogen oxide emissions by lowering the peak temperature can be achieved through lean operation and/or exhaust gas recirculation. The increased inert gas content reduces the reactivity of the mixture, together with the high molecular stability of methane and the higher pressures at the spark timing, this results in greatly increased demands on the ignition systems for gas engines. This can lead to unwanted mis res and high cycle-to-cycle fluctuations. Hydrogen, on the other hand, has a very high reactivity, a wider in flammability range and a much higher laminar flame speed. Mixtures of methane and hydrogen have the potential to extend operating limits to enable even more efficient and lower CO2 emission operating concepts. Up to now, investigations on the e effects of admixture of hydrogen to methane on combustion were focused mainly on engine investigations of performance, efficiency, combustion duration and pollutant emissions, considering various influences such as hydrogen content, fuel-air equivalence ratio, ignition timing, etc. Optical measurements are mainly limited to constant volume cells, where the determination of the laminar flame speed and the stability of the flame are in the spotlight. Optical investigations on the influence of hydrogen admixture on ignition and early flame formation were lacking until now. In the context of this work, an ignition cell is therefore set up to analyze gas mixtures under different boundary conditions by means of spark-induced breakdown spectroscopy. In addition, the influence of different hydrogen admixture rates on the early flame kernel and on the development of the flame front under engine-relevant conditions are investigated in an optically accessible rapid compression expansion machine. Spectroscopic investigations of the spark plasma have shown that the hydrogen admixture up to 50 vol% has no noticeable influence on the ignition voltage requirement. It could be shown that intensity ratios of spectral emission lines of Hα/C2 correlate with the hydrogen admixture rate in methane, but no clear tendencies could be determined for molecular emission spectra in reactive mixtures with air. Spatially and temporally resolved spark-induced breakdown spectroscopy has shown that ratios of atomic emission lines of Hα/O777 and Hα/N746 allow determining local fuel-air equivalence ratios in methane-air mixtures. Moreover, a slight dependence on pressure at spark timing was found under rich conditions. In addition, it could be shown that the broadening of the atomic emission lines is mainly pressure-dependent. Finally, the methodology of spark-induced breakdown spectroscopy was successfully applied to an optical spark plug, enabling the transfer of the methodology to a running engine. Experiments on the rapid compression expansion machine were carried out under quasi-laminar conditions, whereby the interaction of the plasma channel and the early flame kernel with the flow induced by the piston movement was analyzed. These measurements have shown that the hydrogen addition has a noticeable influence on the flame displacement speed, but also on the stretch rate and the curvature of the flame front. Hydrodynamic and thermodiffusive instabilities were monitored by probability density functions of flame curvature, stretch rate and displacement speed. Cellular instabilities started earlier with increasing hydrogen admixture rates and leaner mixtures. The increasing width of the probability density functions of curvature and stretch rate together with increasingly negative values was proposed as a suitable characteristic for the transition to a thermodiffusive unstable flame. An additional air injection at under-expanded conditions shortly before compression was used as turbulence generation mechanism. The resulting tumble flow was visualized by flow field measurements. It was shown that turbulent fluctuation speeds between 3.5 and 5.5 m/s can be achieved at ignition timing and during early flame generation by varying the pressure ratio across the injector.
Data Types:
  • Document
his chapter focuses on organizations’ ability to change between differentmodes of operation as a key adaptive capacity that fosters resilience. Four modesare described which represent responses to low versus high demands on stability andflexibility respectively. The operational requirements for leaders both in enactingthe different modes of operation and in instigating switches between the modes aredetailed. Strategic recommendations are outlined that should help organizations tobuild the needed leadership abilities and to support organizational change towardsbetter handling fundamental tensions and trade-offs embedded in the requirement tostay in control while facing unexpected uncertainties.,Exploring Resilience,ISBN:978-3-030-03189-3,ISBN:978-3-030-03188-6,
Data Types:
  • Document
A search for anomalous electroweak production of WW, WZ, and ZZ boson pairs in association with two jets in proton-proton collisions at s=13TeV at the LHC is reported. The data sample corresponds to an integrated luminosity of 35.9fb−1 collected with the CMS detector. Events are selected by requiring two jets with large rapidity separation and invariant mass, one or two leptons (electrons or muons), and a W or Z boson decaying hadronically. No excess of events with respect to the standard model background predictions is observed and constraints on the structure of quartic vector boson interactions in the framework of dimension-8 effective field theory operators are reported. Stringent limits on parameters of the effective field theory operators are obtained. The observed 95% confidence level limits for the S0, M0, and T0 operators are −2.7,Physics Letters B, 798,ISSN:0370-2693,ISSN:0031-9163,ISSN:1873-2445,
Data Types:
  • Document
Embryonic diapause in the European roe deer includes a period of five months from August to December in which embryonic development is extremely decelerated. Following exit from diapause, the embryo rapidly elongates and subsequently implants. In diapausing carnivores and marsupials, resumption of embryonic growth is regulated by ovarian steroid hormones. In the roe deer, the role of steroid hormones is not known to date. In the present study, progesterone (P4), estradiol-17β (E2) and total estrogens (Etot) were determined in blood plasma and endometrium of roe deer shot in the course of regular huntings between September and December. Steroid hormone concentrations were correlated to the corresponding size of the embryo derived from ex vivo uterine flushing and to the date of sampling. The mean plasma concentrations of P4 (5.4 ± 0.2 ng/ml, mean ± SE, N = 87), E2 (24.3 ± 2.6 pg/ml, N = 86) and Etot (21.7 ± 2.6 pg/ml, N = 78) remained constant over the sampling period and were not correlated to embryonic size. Likewise, endometrial concentrations of P4 (66.1 ± 6.5 ng/ml), E2 (284.0 ± 24.43 pg/ml) and, Etot (440.9 ± 24.43 pg/ml) showed no changes over time. Therefore, it was concluded that ovarian steroid hormones do not play a determining role in resumption of embryonic growth following the period of diapause in the roe deer.,Reproductive Biology, 19 (2),
Data Types:
  • Document