Suchergebnisse

The California Department of Transportation (Caltrans) recently increased to 25 percent the allowable percentage of reclaimed asphalt pavement (RAP) that can be used in new asphalt mixes. A Caltrans-industry task group, formed to consider recent legislation (AB 812) covering the use of RAP in new mixes, has proposed allowing an increase of up to 40 percent binder replacement from a combination of RAP and reclaimed asphalt shingles (RAS). Although these changes can reduce the amount of virgin binder required in new mixes, concerns have been raised regarding the influence that the aged binder in RAP and RAS will have on the new binder properties. Traditionally, solvent extraction and recovery have been used to characterize the rheological and performance properties of the asphalt binder in a mix. This approach has long been criticized for being labor intensive, for altering binder chemical and rheological properties, as being inappropriate for modified asphalt binders, and for creating hazardous chemical disposal issues. In the first phase of a UCPRC study described in this technical memorandum, alternative methods to solvent extraction and recovery were investigated for evaluating the performance properties of asphalt binders blended with RAP and RAS binders. These methods include testing asphalt mortars and fine aggregate matrix (FAM) mixes. This technical memorandum summarizes a literature review on the topic and includes key observations from preliminary laboratory testing. Results from this testing indicate that testing asphalt mortar is probably limited to binder replacement rates not exceeding 25 percent. Preliminary results from FAM mix testing indicate that this method is repeatable and reproducible, and that representative results can be obtained from dynamic shear rheometer (DSR) tests on FAM mix specimens. Proposed further research includes the following: Investigate effective binder replacement rates, the compatibility of virgin binder and aged RAP and RAS binders, the effectiveness of rejuvenating agents, and the influences of production time and temperature on the degree of diffusion and blending of virgin and aged binders. Investigate relationships between the results of asphalt binder and FAM mix testing and identify possible reasons for differences between results focusing on the effect of solvent extraction on blended binder properties. Develop a method for preparing simulated RAP binders that are representative of typical RAP binders at high, intermediate, and low temperatures. Investigate the suitability of two-layer asphalt binder testing as a method for understanding the diffusion/blending mechanism between virgin and RAP and RAS binders.

Abstract. The electron density data recorded by the Langmuir Probe Instrument (ISL, Instrument Sonde de Langmuir) onboard the DEMETER satellite have been collected for nearly 4 yr (during 2006–2009) to perform a statistical analysis. During this time, more than 7000 earthquakes with a magnitude larger than or equal to 5.0 occurred all over the world. For the statistical studies, all these events have been divided into various categories on the basis of the seismic information, including Southern or Northern Hemisphere earthquakes, inland or sea earthquakes, earthquakes at different magnitude levels, earthquakes at different depth levels, isolated events and all events. To distinguish the pre-earthquake anomalies from the possible ionospheric anomalies related to the geomagnetic activity, the data were filtered with the Kp index. The statistical results obviously show that the electron density increases close to the epicentres both in the Northern and the Southern Hemisphere, but the position of the anomaly is slightly shifted to the north in the Northern Hemisphere and to the south in the Southern Hemisphere. The electron density related to both inland and sea earthquakes presents an anomaly approximately close to the epicentres, but the anomaly for sea earthquakes is more significant than for inland earthquakes. The intensity of the anomalies is enhanced when the magnitude increases and is reduced when the depth increases. A similar anomaly can also be seen in the statistical results concerning the isolated earthquakes. All these statistical results can help to better understand the preparation process of the earthquakes and their influence up to the ionospheric levels.

In modern cities, complaining has become an important way for citizens to report emerging urban issues to governments for quick response. For ease of retrieval and handling, government officials usually organize citizen complaints by manually assigning tags to them, which is inefficient and cannot always guarantee the quality of assigned tags. This work attempts to solve this problem by recommending tags for citizen complaints. Although there exist many studies on tag recommendation for textual content, few of them consider two characteristics of citizen complaints, i.e., the spatio-temporal correlations and the taxonomy of candidate tags. In this paper, we propose a novel Spatio-Temporal Taxonomy-Aware Recommendation model (STAR), to recommend tags for citizen complaints by jointly incorporating spatio-temporal information of complaints and the taxonomy of candidate tags. Specifically, STAR first exploits two parallel channels to learn representations for textual and spatio-temporal information. To effectively leverage the taxonomy of tags, we design chained neural networks that gradually refine the representations and perform hierarchical recommendation under a novel taxonomy constraint. A fusion module is further proposed to adaptively integrate contributions of textual and spatio-temporal information in a tag-specific manner. We conduct extensive experiments on a real-world dataset and demonstrate that STAR significantly performs better than state-of-the-art methods. The effectiveness of key components in our model is also verified through ablation studies.

Background The post-disaster mental health crisis intervention (MHCI) system in China remains immature and unsystematic. We aim to report the perceptions of a large sample of MHCI workers and government administrators and provide recommendations for developing a national mental health disaster response management plan in China. Methods An in-depth qualitative study was conducted, collecting data from 20 focus-group discussions and 25 key stakeholder interviews. These recruited participants who had been involved in different types of disaster rescue across 7 provinces/cities where disasters have recently occurred. We used thematic analysis to analyze the data and relevant findings were extracted for policy recommendation. Results Mental health workers' perspectives were examined in detailed according to four core themes: forms of organization, intervention pathway, intervention strategy and technique, and public health information. Post-disaster MHCI should be approached in teams that are integrated with emergency medicine systems, and be led by unified command management. All levels of local health and family planning commission should prepare post-disaster MHCI work plans and build response teams/emergency centres. Future training for MHCI workers should focus on: building a sense of trust within the team; clarifying each member's role; strengthening the screening, assessment and referrals training for psychological professionals; and providing psychological intervention training for Chinese psychiatrists. It is necessary to set up guiding principles for disaster research ethics, mental health rehabilitation and media interaction. Conclusions Through exploring and analyzing the perceptions of current disaster response mental health workers and government administrators, our findings provide essential recommendations for developing a national to county level post-disaster MHCI emergency management plan and can guide the formulation of relevant laws and regulation in China.

Permanent magnets are applied in many large-scale and emerging applications and are crucial components in numerous established and newly evolving technologies. Rare-earth magnets exhibit excellent hard magnetic properties; however, their applications are limited by the price and supply risk of the strategic rare-earth elements. Therefore, there is an increasing demand for inexpensive magnets without strategic elements. Here, the authors report the intrinsic highly-anisotropic magnetic properties of Co and Si co-doped single crystals (Fe1−yCoy)2P1−xSix (y ≈ 0.09). Co increases Curie temperature TC; Si doping decreases magnetocrystalline anisotropy K1 and also increases TC significantly because of the enhanced interlayer interaction. The maximum room temperature magnetocrystalline anisotropy K1 = 1.09 MJ m−3 is achieved for x = 0.22, with saturation magnetization µ0Ms = 0.96 T and TC = 506 K. The theoretical maximum energy product is one of the largest for any magnet without a rare earth or Pt. Besides its promising intrinsic magnetic properties and absence of any strategic elements, other advantages are phase stability at high temperatures and excellent corrosion resistance, which make this material most promising for permanent magnetic development that will have a positive influence in industry and daily life. © 2021 The Authors. Advanced Functional Materials published by Wiley-VCH GmbH. ; This work was financially supported by the Joint Initiative for Research and Innovation within the Fraunhofer and Max Planck cooperation program, an Advanced Grant from the European Research Council (no. 742068) "TOPMAT," the European Union's Horizon 2020 research and innovation programme (no. 824123) "SKYTOP," the European Union's Horizon 2020 research and innovation programme (no. 766566) "ASPIN," the Deutsche Forschungsgemeinschaft (project ID 258499086) "SFB 1143," the Deutsche Forschungsgemeinschaft (project IDs FE 633/30‐1, RE 1164/6‐1, and LU 2261/2‐1) "SPP Skyrmionics", and the DFG through the Würzburg‐Dresden Cluster ...