Mechanical performance and fracture behavior of Fe₄₁Co₇Cr₁₅Mo₁₄Y₂C₁₅B₆ bulk metallic glass

The mechanical properties of a new Fe₄₁Co₇Cr₁₅Mo₁₄Y₂C₁₅B₆ bulk glassy alloy were studied by impact bending, compression, and hardness tests carried out at room temperature. The compressive fracture strength, elastic strain to fracture, Young’s modulus and Vickers hardness were measured to be 3.5 GPa, 1.5%, 265 GPa, and 1253 kg mm⁻², respectively. The fracture mode of the glassy alloy under uniaxial compression is different from those of other bulk metallic glasses in that this fracture mode causes the samples to be broken, in an exploding manner, into a large number of micrometer-scale pieces. The fracture mechanisms of this bulk glassy alloy under bending and uniaxial compression are discussed based on the observation of the fracture surfaces. Vickers indentation tests indicate that the structure of the glassy ingot may be inhomogeneous

N evolution and physiochemical structure changes in chars during co-pyrolysis: Effects of abundance of glucose in fiberboard

© 2020 by the authors. The simple incineration of wood-based panels (WBPs) waste generates a significant amount of NOx, which has led to urgency in developing a new method for treating the N-containing biomass residues. This work aims to examine the N evolution and physiochemical structural changes during the co-pyrolysis of fiberboard and glucose, where the percentage of glucose in the feedstock was varied from 0% to 70%. It was found that N retention in chars was monotonically increased with increasing use of glucose, achieving ~60% N fixation when the glucose accounted for 70% in the mixture. Pyrrole-N (N-5) and Pyridine-N (N-6) were preferentially formed at high ratios of glucose to fiberboard. While the relevant importance of volatile–char interactions to N retention and transformation could be observed, the volatile–volatile reactions from the two feedstocks played a vital role in the increase in abundance of glucose. With the introduction of glucose, the porous structure and porosity in chars from the co-pyrolysis were dramatically altered, whereas the devolatilization of glucose tended to generate larger pores than the fiberboard. The insignificant changes in carbon structure of all chars revealed by Raman spectroscopy would practically allow us to apply the monosaccharides to the WBPs for regulating N evolution without concerns about its side effects for char carbon structures

Indoor Navigation Ontology for Smartphone Semi- Automatic Self-Calibration Scenario

The indoor navigation within public environments and location-based service development are very interesting and promising tasks. This paper describes an ontology-based technique for human movement recognition using the hybrid indoor localization technique based on received signal strength multilateration and pedestrian dead reckoning which relies on internal smartphone sensors. This technique takes into account the anchor node proximity zones and using internal sensors performs the semi-automatic online calibration procedure of log- distance path loss propagation model in accordance with a certain semi-automatic self-calibration scenario. The usage of indoor navigation ontology allows to decrease the influence of radio signal obstructions induced by user's body and moving people

Disentangling the effects of vapor pressure deficit on northern terrestrial vegetation productivity

The impact of atmospheric vapor pressure deficit (VPD) on plant photosynthesis has long been acknowledged, but large interactions with air temperature (T) and soil moisture (SM) still hinder a complete understanding of the influence of VPD on vegetation production across various climate zones. Here, we found a diverging response of productivity to VPD in the Northern Hemisphere by excluding interactive effects of VPD with T and SM. The interactions between VPD and T/SM not only offset the potential positive impact of warming on vegetation productivity but also amplifies the negative effect of soil drying. Notably, for high-latitude ecosystems, there occurs a pronounced shift in vegetation productivity\u27s response to VPD during the growing season when VPD surpasses a threshold of 3.5 to 4.0 hectopascals. These results yield previously unknown insights into the role of VPD in terrestrial ecosystems and enhance our comprehension of the terrestrial carbon cycle\u27s response to global warming

Global Freshwater availability below normal conditions and population impact under 1.5°C and 2°C stabilization scenarios

Based on the large ensembles of the half a degree additional warming, prognosis, and projected impacts historical, +1.5 and +2 °C experiments, we quantify changes in the magnitude of water availability (i.e., precipitation minus actual evapotranspiration; a function of monthly precipitation flux, latent heat flux, and surface air temperature) below normal conditions (less than median, e.g., 20th percentile water availability). We found that, relative to the historical experiment, water availability below normal conditions of the +1.5 and +2 °C experiments would decrease in the midlatitudes and the tropics, indicating that hydrological drought is likely to increase in warmer worlds. These cause more (less) people in East Asia, Central Europe, South Asia, and Southeast Asia (West Africa and Alaska/Northwest Canada) to be exposed to water shortage. Stabilizing warming at 1.5 °C instead of 2 °C would limit population impact in most of the regions, less effective in Alaska/Northwest Canada, Southeast Asia, and Amazon. Globally, this reduced population impact is ~117 million people

Contrasting fate of western Third Pole's water resources under 21st century climate change

Seasonal melting of glaciers and snow from the western Third Pole (TP) plays important role in sustaining water supplies downstream. However, the future water availability of the region, and even today’s runoff regime, are both hotly debated and inadequately quantified. Here, we characterize the contemporary flow regimes and systematically assess the future evolution of total water availability, seasonal shifts, and dry and wet discharge extremes in four most meltwater-dominated basins in the western TP, by using a process-based, well-established glacier-hydrology model, well-constrained historical reference climate data, and the ensemble of 22 global climate models with an advanced statistical downscaling and bias correction technique. We show that these basins face sharply diverging water futures under 21st century climate change. In RCP scenarios 4.5 and 8.5, increased precipitation and glacier runoff in the Upper Indus and Yarkant basins more than compensate for decreased winter snow accumulation, boosting annual and summer water availability through the end of the century. In contrast, the Amu and Syr Darya basins will become more reliant on rainfall runoff as glacier ice and seasonal snow decline. Syr Darya summer river-flows, already low, will fall by 16–30% by end-of-century, and striking increases in peak flood discharge (by >60%), drought duration (by >1 month) and drought intensity (by factor 4.6) will compound the considerable water-sharing challenges on this major transboundary river

Anthropogenic Aerosols Cause Recent Pronounced Weakening of Asian Summer Monsoon Relative to Last Four Centuries

The Asian Summer Monsoon (ASM) affects ecosystems, biodiversity, and food security of billions of people. In recent decades, ASM strength (as represented by precipitation) has been decreasing, but instrumental measurements span only a short period of time. The initiation and the dynamics of the recent trend are unclear. Here for the first time, we use an ensemble of 10 tree ring-width chronologies from the west-central margin of ASM to reconstruct detail of ASM variability back to 1566 CE. The reconstruction captures weak/strong ASM events and also reflects major locust plagues. Notably, we found an unprecedented 80-year trend of decreasing ASM strength within the context of the 448-year reconstruction, which is contrary to what is expected from greenhouse warming. Our coupled climate model shows that increasing anthropogenic sulfate aerosol emissions over the Northern Hemisphere could be the dominant factor contributing to the ASM decrease. Plan Language Summary Monsoonal rainfall has a certain influence on agriculture and industry in the regions of Asian Summer Monsoon (ASM). An understanding of the spatial-temporal variability of the ASM and the associated dynamics is vital for terrestrial ecosystems, water resources, forests, and landscapes. We have developed a 448-year ASM reconstruction back to 1566 CE using 10 tree ring chronologies from the margin region of ASM. We find that historical severe droughts and locust plague disasters during weak ASM events. The recent decreasing ASM trend persisting for over 80 years is unprecedented over the past 448 years. Coupled climate models show that increasing anthropogenic aerosol emissions are the dominant underlying factor. Our aim is that the time series will find a wide range of utility for understanding past climate variability and for predicting future climate change.National Natural Science Foundation of China [41630531]; National Research Program for Key Issues in Air Pollution Control [DQGG0104]; Chinese Academy of Sciences [QYZDJ-SSW-DQC021, XDPB05, GJHZ1777]; Institute of Earth Environment, Chinese Academy of Sciences; State Key Laboratory of Loess and Quaternary Geology6 month embargo; first published: 09 April 2019This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

GJB2 mutation spectrum in 2063 Chinese patients with nonsyndromic hearing impairment

Background: Mutations in GJB2 are the most common molecular defects responsible for autosomal recessive nonsyndromic hearing impairment (NSHI). The mutation spectra of this gene vary among different ethnic groups. Methods: In order to understand the spectrum and frequency of GJB2 mutations in the Chinese population, the coding region of the GJB2 gene from 2063 unrelated patients with NSHI was PCR amplified and sequenced. Results: A total of 23 pathogenic mutations were identified. Among them, five (p.W3X, c.99delT, c.155_c.158delTCTG, c.512_c.513insAACG, and p.Y152X) are novel. Three hundred and seven patients carry two confirmed pathogenic mutations, including 178 homozygotes and 129 compound heterozygotes. One hundred twenty five patients carry only one mutant allele. Thus, GJB2 mutations account for 17.9% of the mutant alleles in 2063 NSHI patients. Overall, 92.6% (684/739) of the pathogenic mutations are frame-shift truncation or nonsense mutations. The four prevalent mutations; c.235delC, c.299_c.300delAT, c.176_c.191del16, and c.35delG, account for 88.0% of all mutantalleles identified. The frequency of GJB2 mutations (alleles) varies from 4% to 30.4% among different regions of China. It also varies among different sub-ethnic groups. Conclusion: In some regions of China, testing of the three most common mutations can identify at least one GJB2 mutant allele in all patients. In other regions such as Tibet, the three most common mutations account for only 16% the GJB2 mutant alleles. Thus, in this region, sequencing of GJB2 would be recommended. In addition, the etiology of more than 80% of the mutant alleles for NSHI in China remains to be identified. Analysis of other NSHI related genes will be necessary

Deciphering the origin of the Cenozoic intracontinental rifting and volcanism in eastern China using integrated evidence from the Jianghan Basin

Intracontinental rifting and low-volume volcanism are a globally common phenomenon, yet the underlying driving mechanisms and whether they can be explained through classic plate tectonic concepts, remain hotly debated. A prominent example is the Cenozoic rift and volcanic province in eastern China. Using an integration of geological, geophysical and geochemical data, we unravel the spatial and temporal variations of the rifting and volcanism in the Jianghan Basin. Both rifting and volcanism in the Jianghan Basin show two intense-to-weak cycles (65–50 Ma and 50–26 Ma, respectively) with significant enhancement in activity during the late rift phase. Moreover, rifting and depocentres progressively migrated eastward. The Jianghan basalts all share an asthenospheric origin while the source of the late phase basalts is slightly more enriched and heterogenous in Nd-Hf isotopes than that of the early phase basalts. The late phase basalts also display a smaller extent of partial melting even under a thinner lithosphere, likely indicating a significant decrease of volatile content in the mantle source. Based on regional tectonic correlations, the main stages of tectonic evolution of the Jianghan Basin and eastern China are not synchronous with changes in Pacific plate motion, while they are coincident with India-Asia collision processes. These observations lead us to propose that the asthenospheric flow driven by India-Asia collision rather than the rollback of the subducted Pacific slab has caused the widespread rifting and volcanism in eastern China. The variations of rifting and volcanism in the Jianghan Basin suggest a multiphase and eastward asthenospheric flow beneath eastern China driven by India-Asia collision, with an intense upwelling when passing through the North-South Gravity Lineament (NSGL). The much more intense rifting and volcanism during the late rift phase may indicate a much larger scale of volatile-poor asthenospheric flow than the early rift phase which could result in a more intense erosion of ancient enriched lithospheric mantle and the volatile content in the mantle source dropping sharply. This study provides an improved model based on our multidisciplinary observations for asthenospheric flow which may be an alternative driving mechanism for intracontinental rifting and low-volume volcanism in the regions where there are step changes in lithospheric thickness globally