ABSTRACT
Aerial photography was conducted in the high Arctic Ocean during a Chinese research expedition in summer 2010. By partitioning the images into three distinct surface categories (sea ...ice/snow, water and melt ponds), the areal fraction of each category, ice concentration and the size and geometry of individual melt ponds, are determined with high-spatial resolution. The ice concentration and melt pond coverage have large spatial deviations between flights and even between images from the marginal ice zone to the pack ice zone in the central Arctic. Ice concentration and pond coverage over high Arctic (from 84°N to north) was ~75% and ~6.8%, respectively, providing ‘ground truth’ for the unusual transpolar reduction strip of ice indicated concurrently by AMSR-E data and for the regions (north of 88°N) where no passive microwave sensors can cover. Melt pond size and shape distributions are examined in terms of pond area (
S
), perimeter (
P
), mean caliper dimension (MCD) (
L
), roundness (
R
), convex degree (
C
), the ratio of
P
/
S
and fractal dimension (
D
). Power-law relationships are developed between pond size and number. Some general trends in geometric metrics are identified as a function of pond area including
R, C, P
/
S
and
D
. The scale separation of pond complexity is demonstrated by analyzing area-perimeter data. The results will potentially help the modelling of melt pond evolution and the determination of heterogeneity of under-ice transmitted light fields.
The overall goal of this study is to investigate the effect of sulfidated nanoscale zerovalent iron (S-nZVI) on the removal of hexavalent molybdate (MoO
) under different aquatic chemistry ...conditions. Surface analysis suggests that Mo(VI) is removed mainly by adsorption and co-precipitation onto the surface of S-nZVI and a small amount of Mo(VI) can be reduced to Mo(V) species. The results of batch tests show that Mo(VI) removal by S-nZVI are well described with the pseudo-second-order adsorption model. The removal rate increases with a decrease in solution pH (4.0-9.0) and is significantly affected by the S/Fe ratio of S-nZVI, with the optimal S/Fe ratio being 0.5. The presence of anions WO
or CrO
can reduce the Mo(VI) removal, which is likely because they compete for adsorption sites on the solid surfaces. The divalent cations Ni
, Cu
and Co
also inhibit the removal of Mo(VI) whereas Zn
, Ca
and Mg
enhance it. After being aged for 35 d in water, S-nZVI still exhibits high reactivity towards Mo(VI) removal (57.39%). The study demonstrates that S-nZVI can be used as an environmentally friendly material for effectively removing Mo(VI) from contaminated water.
Ordered graphene nanodisk arrays have been successfully fabricated by combining nanosphere lithography and reactive ion etching (RIE) processes. The dimension of graphene nanodisks can be effectively ...tuned by varying the size of polystyrene spheres, which function as masks during RIE. Low-voltage scanning electron microscopy shows that the graphene sheet could be readily patterned into periodic disklike nanostructures by oxygen RIE. Raman mapping and spectroscopy further visualize such nanodisk arrays and reveal that the nature of disks are crystalline single layer graphene. This work demonstrates an efficient and manageable way to pattern graphene. By consideration of the periodicity, nanometer dimension, and high edge density compared to large-area graphene sheets, graphene nanodisk arrays, such two-dimensional assembly of carbon atoms, offer intrisic advantages in various electronic and spintronic fabrications.
The purpose of the present study was to investigate the effect of carbohydrate-electrolyte solution (CE), lemon tea (LT), and distilled water (DW) on rehydration and cognitive performance after 60 ...min of moderate exercise. 9 healthy males and 10 eumenorrheic females completed 3 runs in a randomized crossover study design. During the 4-h recovery (REC) period, they consumed either a volume of CE, LT or DW equal to 150% of their body mass (BM) loss during the previous run. The 3 beverages vary in carbohydrate and electrolyte content. A battery of cognitive tests was performed upon arrival, immediately after exercise, and at the end of REC. After the REC, the restoration of BM loss was lower in the DW and LT trials than that in the CE trial in the female participants (CE vs. LT vs. DW: 59.3±2.8 vs. 41.7±5.7 vs. 45.6±2.2%). When compared with the DW, the accuracy of performances during a working memory task in both males and females was higher in the CE and LT trials. The results suggested that during a short-term recovery, both LT and CE show certain beneficial effect in maintaining cognitive performance. However, CE appears to be more effective than LT and DW in rehydrating female participants.
Polyphosphate, an energy-rich polymer conserved in all kingdoms of life, is integral to many cellular stress responses, including nutrient deprivation, and yet, the mechanisms that underlie its ...biological roles are not well understood. In this work, we elucidate the physiological function of this polymer in the acclimation of the model alga
to nutrient deprivation. Our data reveal that polyphosphate synthesis is vital to control cellular adenosine 5'-triphosphate homeostasis and maintain both respiratory and photosynthetic electron transport upon sulfur deprivation. Using both genetic and pharmacological approaches, we show that electron flow in the energy-generating organelles is essential to induce and sustain acclimation to sulfur deprivation at the transcriptional level. These previously unidentified links among polyphosphate synthesis, photosynthetic and respiratory electron flow, and the acclimation of cells to nutrient deprivation could unveil the mechanism by which polyphosphate helps organisms cope with a myriad of stress conditions in a fluctuating environment.
AbstractGroundwater at many existing or former industrial areas and underground storage tank sites is contaminated by petroleum hydrocarbons. In this study, a column experiment was applied to ...evaluate the effectiveness and mechanisms of sulfate reduction processes on the bioremediation of benzene, toluene, and methyl-t-butyl ether (MTBE) contaminated groundwater. Simulated anaerobic groundwater containing benzene, toluene, and MTBE (average concentration = 20 mg/L) was pumped into the system at a flow rate of 0.36 mL/min. Sulfate (used as the electron acceptor) was injected into the system to activate the sulfate-reducing process. Anaerobic sludge collected from an anaerobic basin of an industrial wastewater treatment plant was inoculated into the system to enhance the sulfate reduction rate. Up to 92, 65, and 45% of toluene, benzene, and MTBE removal efficiencies were observed with the first-order decay rate of 34, 1.8, and 11/d, respectively. Results indicate that toluene is more biodegradable under sulfate-reducing conditions compared to benzene and MTBE, and 0.7 g/L of sulfate consumption was observed during the biodegradation process. The occurrence of sulfate reduction can be confirmed by the increased sulfide (increased from 7–9 to 340–520 mg/L) and ferrous iron (increased from <0.1 to 52 mg/L, then dropped to 0.14 mg/L attributable to the formation of iron sulfide) concentrations. In the latter part of this study, accumulation of hydrogen sulfide caused the microbial inhibition, and thus, decreased contaminant removal efficiencies were observed. The microbial communities were characterized by 16S rRNA-based denaturing gradient gel electrophoresis (DGGE) profiling for soils in the system. Results show that sulfate addition could result in the enhancement of sulfate reducer growth, and thus, sulfate reduction becomes the dominant biodegradation process. A total of 39 different petroleum-hydrocarbon degrading bacteria were observed under the sulfate-reducing conditions. Results indicate that the sulfate reduction has the potential to be developed into a practically and economically acceptable technology to remediate petroleum-hydrocarbon contaminated groundwater.
This study compared the agronomic properties of rice husk biochar (RHB) and wood biochar (WB) and investigated their effect on the growth rate of water spinach in a field experiment. Each biochar ...type was tested at 5 different rates of 4.0, 3.0, 2.0, 1.0 and 0.5 kg m3, respectively. The results detailing the growth of water spinach showed that the application of rice husk biochar improves biomass production. The WB added to soil increased the plant weight of water spinach by increasing the root size and leaf width, whereas RHB added to soil increased plant weight by increasing the stem size and leaf length of the water spinach. In addition, the stem size of water spinach was proportional to the WHC/silt ratio; whereas the root size of water spinach was proportional to the OM/OC ratio of soil. We also proposed that the working mechanism of WB and RHB in soil would be such, that the decomposition of OC in biochar-added soil to OM resulted in increased WHC and decreased silt in biochar-added soil. The decomposition of WB biochar was faster than RHB under a lower dosage amount (< 1.5 kg m3), but this trend was inversed with a higher dosage ( > 3.0 kg m3).
With the development of spatial information technology, the amount of geographic information data shows an explosive growth, which puts forward higher demands on the time efficiency and visualization ...effect of geographic information data release. vector tile maps have become the main map service mode in the fields of Internet maps and GIS industries because of the advantages of its powerful interactive capabilities, efficient data transmission and lower storage costs. In order to construct massive vector tiles quickly and enhance the scalability of vector tiles application, this paper researched the vector tiles construction technology based on the distributed computing framework. Firstly, we introduced the construction process of vector tiles such as pyramid model, data organization and data generalization, Specifically, the data generalization methods of different geometric types were discussed. Second, Apache Sedona, the distributed computing framework were researched and the advantages for vector data processing is introduced. Then, the Sedona based parallel construction technology is proposed, and pipeline optimization of Spark is applied in this process. Third, a comparative experiment to evaluate the performance were conducted, the result showed that the parallel construction technology had obvious performance advantages, the greater the volume and extent of vector data, the greater the advantage.
The artificial intelligence technique is utilized to improve evaluation of thermally induced solid-state reaction kinetics. A general regression neural network (GRNN) model was applied to directly ...determine the kinetic triplets, i.e., activation energy, pre-exponential factor, and mechanism model. The effect of number of heating rate on prediction performance of the GRNN model was assessed based on the estimation indictors. The obtained kinetic triplets based on the triple heating rates were considered to be accepted. The prediction ability of the GRNN model was very robust at more than three heating rates. The relative errors for kinetic parameters derived from five heating rates were within ± 4%, and the cognition rates for mechanism models were up to 99.6%. The developed GRNN model was successfully applied in the high-temperature synthesis of Li
4
Ti
5
O
12
/C composites. It is expected that the model also could be extended to estimate the kinetics of other solid-state reactions.
A novel vertical C-shaped-channel nanosheet field-effect-transistor (VCNFET) featured with precise control of channel-thickness and gate-length, and a unique integration flow of Dual Side Process ...(DSP) are proposed in this work. The VCNFETs were fabricated by high quality Si/SiGe epitaxy, atomic layer etching with nanometer-scale process control and self-aligned high-k metal gate (HKMG). The integration flow is compatible with mainstream CMOS technology. Thanks to the precise control of channel thickness and doping profiles, perfect SS of 61 mV/dec, small DIBL of 8 mV/V, and remarkably large <inline-formula> <tex-math notation="LaTeX">\text{I}_{\text {on}}/\text {I}_{\text {off}} </tex-math></inline-formula> ratio of <inline-formula> <tex-math notation="LaTeX">{6.28}\times {10}^{{9}} </tex-math></inline-formula> were achieved. The device performance and it's optimization were also investigated with the reduction of the external resistance and numerical simulations.
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