• Energy Research
• 2016-2025close
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SignificanceEstimates of nutrient allocation in different plant tissues and the relationships between the nutrient contents and photosynthetic capacity are critical to predicting ecosystem carbon sequestration under global change. Here, we provide an assessment of large-scale patterns of community-level nitrogen and phosphorus concentrations in different plant tissues and then examine how nutrient allocations are coupled with plant productivity. The results show that nutrient concentrations in leaves are less responsive to abiotic environments than those in woody stems and roots (stable leaf nutrient concentration hypothesis); the relationships between vegetation primary productivity and leaf nutrient contents are stronger when less nutrients are allocated to the woody tissues (productivity–nutrient allocation hypothesis) and are stronger in deciduous than in evergreen vegetation (productivity–leaf lifespan hypothesis).

Abstract To alleviate the shortage of natural gas resource and ease carbon emissions, a novel solar-driven combined cooling, heating and power (CCHP) system is designed and optimized using the genetic algorithm in the work. Different from the process of direct combustion in a conventional CCHP system, natural gas is firstly converted into syngas by a solar-driven natural gas reforming step, which is consumed in an efficient tri-generation system. Energy, economic and environmental evaluations on five office buildings in different climate zones in China are implemented to validate the advantages of the proposed system. Results show that the annual maximum primary energy saving, total cost saving, and CO2 emission reduction are 69.76%, 49.80%, and 71.55%, respectively. The system located in severe cold zones, where solar energy is abundant and building requires more heat load in whole year, achieves the highest benefits in comparison with separate systems. Furthermore, the sensitivities on the price fluctuations of electricity, natural gas and solar field to the system profits are investigated, which indicates that the influence of electricity price on the system performance is the most significant. Thus, a promising method for reducing the natural gas consumption and improving the utilization efficiency of solar energy is provided.

In this study, Myriophyllum elatinoides growth under different nitrogen (N) concentrations (2, 250, 300, 350 and 400 mg L-1) and changes in rhizosphere bacterial community structure were investigated. High N (>300 mg L-1) concentrations caused reduction in M. elatinoides biomass. Growth tended to stabilize at 49 days. N concentration in roots were higher than that in stems and leaves under high N conditions. TN and NH4+ removal efficiencies reached 84.0% and 87.2%, respectively, in M. elatinoides surface flow constructed wetlands (SFCWs). Rhizosphere bacterial diversity increased over time. Proteobacteria, Firmicutes, Cyanobacteria, and Bacteroidetes dominated at the phylum level. Genera Turicibacter, Allochromatium, and Methylocystis increased at low N (<300 mg L-1) concentrations, while Pseudomonas increased at high N concentrations over the experimental period. Redundancy analysis showed that pH was strongly correlated with changes in rhizosphere bacterial community structure. These findings helped to insight into N removal mechanism in M. elatinoides.

Abstract The Liquefied natural gas (LNG) cryogenic submerged pump, the core power equipment for the transportation of liquefied natural gas, is prone to cavitation. However, based on the traditional analysis of the pressure drop, the irreversible loss after cavitation can barely be displayed quantitatively. To solve this problem, an entropy production diagnostic model (EPDM) by the contribution of viscous entropy production (VEP), turbulent entropy production (TEP) and wall entropy production (WEP) for the cavitation flow was established to calculate the energy loss. The cryogenic cavitation model and proposed EPDM were proved to be reliable after comparing results with Hord’s experiment in an ogive and cavitation experiment in a centrifugal pump. Then, by studying the total entropy production, it was found that the EPDM could well predict the occurrence of the critical cavitation and the deterioration of cavitation. When compared with TEP and WEP, the effect of VEP is negligible. As the cavitation area expands from the suction surface of inducer (id) to the first-stage impeller (impA), the cavitation process can be divided into three stages and the total energy loss increases significantly from the first stage to the third one. Through the global distribution of energy loss, it was found that the faster growth of the loss in the second-stage impeller (impB) and the second-stage guide vane (gvB), not in id and impA, contributes more to the energy loss after cavitation. Finally, from the variation of ratio of TEP to WEP, it reveals that cavitation has a greater effect on the WEP rate for the impB, but the turbulent viscous dissipation is still dominant, while the eddy dissipation and resistance loss in gvB with the evolution of cavitation are both crucial.

The Space Radiobiological Exposure Facility (SREF) is a general experimental facility at the China Space Station for scientific research in the fields of space radiation protection, space radiation biology, biotechnology, and the origin of life. The facility provides an environment with controllable temperatures for experiments with organic molecules and model organisms such as small animals, plant seeds, and microorganisms. The cultivation of small animals can be achieved in the facility with the use of microfluidic chips and images and videos of such experiments can be captured by microscopy. SREF also includes a linear energy transfer (LET) detector, neutron detectors, and a solar ultraviolet (UV) detector to measure the LET spectrum of the charged particles, energy spectrum and dose equivalent of neutrons, and fluence of solar UV radiation, respectively. The facility is reusable, and the model organisms from the first exposure experiment were recovered in orbit and returned to the ground for further study.

Abstract Comprehensive information about the concentrations, distribution, and modes of occurrence of elements in coal are important from the environmental and economic point of view. Although a great number of previous studies have investigated the geology of coalbed methane in the Qinshui Basin, only a few studies focused on the inorganic constituents in coal. More specifically, the mode of occurrences of valuable element Li in the No. 3 Coal is still unclear, although Li was found enriched. In this study, we present mineral characteristics, as well as multi-element data on the Permian No. 3 Coal from the Sucun and Gaohe Mines, Changzhi City, southern Qinshui Basin. The studied coals are characterized by low- to medium-ash yield (Ad = 5.72%- 28.18%, 12.34% on average), low volatile matter yield (Vdaf = 8.49–15.17%, 10.96% on average), suggesting a low volatile bituminous coal to semi-anthracite. NH4-illite and kaolinite are the main minerals in the coals detected by XRD, and trace amount of minerals calcite, dolomite, quartz, pyrite and diaspore can also be found. The major elements of the studied No. 3 coals are dominated by SiO2 and Al2O3, ranging 2.49–16.45 wt% and 2.13–12.9 wt% (on a whole-coal basis), respectively. Li is enriched in the No. 3 coals (5

Hanging glaciers hold the absolute dominant number in West China and their changes had important influences on local hydrology, sea-level rise and natural hazards (snow/ice avalanches). However, logistic and operational difficulties have resulted in the lack of in-situ-measured data, leaving us with poor knowledge of the changing behaviors of this type of glacier. Here, we presented the spatiotemporal pattern of seasonal and annual mass changes of a mid-latitude hanging glacier in the Tien Shan based on repeated terrestrial laser scanning (TLS) surveys during the period 2016–2018. The distributed glacier surface elevation changes exhibited highly spatiotemporal variability, and the winter elevation changes showed slight surface lowering at the upper elevations and weak thickening at the glacier terminus, which was contrary to altitudinal elevation changing patterns at the summer and annual scales. Mass balance processes of the hanging glacier mainly occurred during summer and the winter mass balance was nearly balanced (−0.10 ± 0.15 m w.e.). The glacier exhibited more rapid mass loss than adjacent other morphological glacier and the estimated response time of the glacier to climate change was very short (6–9 years), indicating hanging glaciers will experience rapid wastage and disappearance in the future even with climate change mitigation.