43 research outputs found

    Decay and expansion of the early aftershock activity following the 2011, M_w9.0 Tohoku earthquake

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    The 2011, M_w9.0 Tohoku earthquake was followed by an abundant amount of seismicity providing a unique opportunity to analyze the triggering mechanism of great earthquakes. Although the Tohoku earthquake occurred close to a dense seismic network, many aftershocks that occurred in the first few hours after the mainshock are not recorded in the earthquake catalogs. Here we use a template waveform approach to recover as many as possible missing events in the first 12 hours following the Tohoku mainshock. Our analysis is able to detect about 1.4 times more events than those listed in the High Sensitivity Seismograph (Hi-net) earthquake catalog. Combining our new dataset with earthquakes that occurred at latter times, we are able to observe a continuous decay of the aftershock rate and along strike expansion of aftershock area. We relate the latter observation to the occurrence of post-seismic slip over the deep interface

    Oscillatory behavior of hollow grid cathode discharges

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    Multiple complex space-charge structures in unmagnetized low-temperature plasmas arise from ionization phenomena near additional negatively or positively biased electrodes or due to local constraints. Because of their usually spherical form, such structures are called fireballs. If they appear inside hollow grids, they are called inverted fireballs or plasma bubbles. The temporal evolution of such structures is often accompanied by strong plasma instabilities. The dynamics of complex space-charge structures have been investigated by using single spherical grid cathode with an orifice. Langmuir probe and optical emission spectroscopy were used to diagnose the structures. Measurements delivered the axial profiles of the plasma potential, electron temperature and density, and the densities of excited atoms and ions, that confirmed the formation of a fireball in the region near the orifice (also evidenced by visual observation). Inside the grid, a plasma bubble has developed, with a high ion density inside due to the hollow cathode effect. Information on the nonlinear dynamics of the complex space charge structures was obtained from the analysis of the oscillations of the discharge current

    The Adaptive Thermal Comfort Review from the 1920s, the Present, and the Future

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    The typical method for comfort analysis is the Predicted Mean Vote and Predicted Percentage Dissatisfied (PMV-PPD). However, they present limitations in accommodating the comfort of a disabled and elder group of people, which are the most vulnerable to climate change and energy poverty. The adaptive method can give flexibility and personalisation needed to overcome the problem due to the variability of the people's metabolism, historical and behavioural preferences. Investments to upgrade the indoor environmental quality and building design can then be effectively used and, for the first time, it will be possible to tailor the solutions for these particular groups of people. The adaptive approach uses Artificial Intelligence (AI), where it can introduce the imperfect learning process. Overcoming this, instead of going further for the Explainable AI, the PMV–PPD approach can be used for the learning validation and verification needed for the adaptive setting point and standards

    Status and Trends of Physical Activity Surveillance, Policy, and Research in 164 Countries: Findings From the Global Observatory for Physical Activity—GoPA! 2015 and 2020 Surveys

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    Background: Physical activity (PA) surveillance, policy, and research efforts need to be periodically appraised to gain insight into national and global capacities for PA promotion. The aim of this paper was to assess the status and trends in PA surveillance, policy, and research in 164 countries. Methods: We used data from the Global Observatory for Physical Activity (GoPA!) 2015 and 2020 surveys. Comprehensive searches were performed for each country to determine the level of development of their PA surveillance, policy, and research, and the findings were verified by the GoPA! Country Contacts. Trends were analyzed based on the data available for both survey years. Results: The global 5-year progress in all 3 indicators was modest, with most countries either improving or staying at the same level. PA surveillance, policy, and research improved or remained at a high level in 48.1%, 40.6%, and 42.1% of the countries, respectively. PA surveillance, policy, and research scores decreased or remained at a low level in 8.3%, 15.8%, and 28.6% of the countries, respectively. The highest capacity for PA promotion was found in Europe, the lowest in Africa and low- and lower-middle-income countries. Although a large percentage of the world’s population benefit from at least some PA policy, surveillance, and research efforts in their countries, 49.6 million people are without PA surveillance, 629.4 million people are without PA policy, and 108.7 million live in countries without any PA research output. A total of 6.3 billion people or 88.2% of the world’s population live in countries where PA promotion capacity should be significantly improved. Conclusion: Despite PA is essential for health, there are large inequalities between countries and world regions in their capacity to promote PA. Coordinated efforts are needed to reduce the inequalities and improve the global capacity for PA promotion

    Spatial Variations of Aftershock Parameters and their Relation to Geodetic Slip Models for the 2010 Mw8.8 Maule and the 2011 Mw9.0 Tohoku-oki Earthquakes

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    Recent development in analysis tools and deployments of the geodetic and seismic instruments give an opportunity to investigate aftershock sequences at local scales, which is important for the seismic hazard assessment. In particular, we study the dependencies between aftershock sequences properties and deformational/geological data on a scale of the rupture extension of megathrust earthquakes. For this goal we use, on one hand, published models of inter-, co- and postseismic slip and geological information and, on the other hand, aftershock parameters, obtained by fitting a modified Epidemic Type Aftershock Sequence (ETAS) model. The altered ETAS model takes into account the mainshock rupture extension and it distinguishes between primary and the secondary aftershock triggering involved in the total seismicity rate. We estimate the Spearman correlation coefficients between the spatially distributed aftershock parameters estimated by the modified ETAS model and crustal physical properties for the Maule 2010 Mw8.8 and the Tohoku-oki 2011 Mw9.0 aftershock sequences. We find that: (1) modified ETAS model outperforms the classical one, when the mainshock rupture extension cannot be neglected and represented as a point source; (2) anomalous aftershock parameters occur in the areas of the reactivated fault systems; (3) aftershocks, regardless of their generation, tend to occur in the areas of high coseismic slip gradient, afterslip and interseismic coupling; (4) aftershock seismic moment releases preferentially in regions of large coseismic slip, coseismic slip gradient and interseismically locked areas; (5) b value tends to be smaller in interseismically locked regions

    Novel phosphorous-nitrogen intumescent flame retardant system. Its effects on flame retardancy and thermal properties of polypropylene

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    This paper describes the effectiveness of novel phosphorous-nitrogen intumescent flame retardant system (ammonium polyphosphate 202 and PPM Triazine HF - trademark, abbrev. IS) on fire retardancy and thermal stability properties of polypropylene (abbrev. PP) at incorporation level below the standard amount required for intumescent flame retardant system. UL-94 vertical burning test revealed that the addition of 20 wt.% of IS into neat PP is enough to reach V-0 rating (short burn without dripping). Further, a higher increase of the oxygen concentration for ignition was also found with the addition of the novel intumescent flame retardant to neat PP; LOI value of neat PP by addition of 20 wt.% IS rose from 19 to 31 vol.%. Finally, a remarkable decrease of peak heat release rate (PHRR: −91%), total heat release (THR: −42%), average of mass loss rate (AMLR: −92%), average of specific extinction aria (ASEA: −48%) and total smoke release (TSR: −58%) was revealed with increasing in IS content. Novel intumescent flame retardant system showed good flame retardancy performance pointing out that the intumescent char formed resists oxidation; this aspect was also confirmed by the thermogravimetry analysis. Hence, it can be pointed out that the improvement of flame retardancy imparted by the novel intumescent flame retardant system at lower concentration enables on one side a lower cost material formulation and on the other side the impact on the mechanical properties of the polymer might be lower. The thermo-oxidative data have revealed an enhancement of the thermal stability of the PP matrix by incorporation of IS (the PP/20IS composite showed a markedly increase in Tonset: 14 °C and Tmax: 64 °C)
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