| 1. |
- Wan, Hongyu, et al.
(författare)
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Trace analysis using Wi-Fi probe positioning and virtual reality for commercial building complex design
- 2023
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Ingår i: Automation in Construction. - : Elsevier BV. - 0926-5805 .- 1872-7891. ; 153
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Tidskriftsartikel (refereegranskat)abstract
- The effective management of human flow is critical to the success of complex projects in urban centers, such as shopping malls. However, conventional methods of flow organization, which rely on observation and empirical knowledge, face challenges in fully comprehending the intricate environment. This study proposes an analytical approach to manage human flow in shopping malls in urban centers. A Wi-Fi probe positioning system recorded real-time human flow to assess current movement patterns, while virtual reality (VR) identified issues and optimized the space layout. The Maoye shopping mall in Nanjing experienced a decline in human flow, prompting the need for a new design. The study demonstrates that the Wi-Fi probe positioning system supports the setting of entrances and main corridors during the design phase, while VR tracing evaluates space layout and aids optimization. The study contributes to data-informed design by integrating analytical approaches into the conventional design process.
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| 2. |
- Li, Siyu, et al.
(författare)
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Comprehensive assessment of dissolved organic matter processing in the Amazon River and its major tributaries revealed by positive and negative electrospray mass spectrometry and NMR spectroscopy
- 2023
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Ingår i: Science of the Total Environment. - : ELSEVIER. - 0048-9697 .- 1879-1026. ; 857
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Tidskriftsartikel (refereegranskat)abstract
- Rivers are natural biogeochemical systems shaping the fates of dissolved organic matter (DOM) from leaving soils to reaching the oceans. This study focuses on Amazon basin DOM processing employing negative and positive electro-spray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI[+/-] FT-ICR MS) and nuclear mag-netic resonance spectroscopy (NMR) to reveal effects of major processes on the compositional space and structural characteristics of black, white and clear water systems. These include non-conservative mixing at the confluences of (1) Solimoes and the Negro River, (2) the Amazon River and the Madeira River, and (3) in-stream processing of Amazon River DOM between the Madeira River and the Tapajos River. The Negro River (black water) supplies more highly oxygenated and high molecular weight compounds, whereas the Solimoes and Madeira Rivers (white water) contribute more CHNO and CHOS molecules to the Amazon River main stem. Aliphatic CHO and abundant CHNO compounds prevail in Tapajos River DOM (clear water), likely originating from primary production. Sorption onto particles and heterotrophic microbial degradation are probably the principal mechanisms for the observed changes in DOM composition in the Amazon River and its tributaries.
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| 3. |
- Li, Siyu, et al.
(författare)
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Distinct Non-conservative Behavior of Dissolved Organic Matter after Mixing Solimoes/Negro and Amazon/Tapajo s River Waters
- 2023
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Ingår i: ACS - ES & T Water. - : AMER CHEMICAL SOC. - 2690-0637. ; 3:8, s. 2083-2095
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Tidskriftsartikel (refereegranskat)abstract
- Positive and negative electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry and H-1 NMR revealed major compositional and structural changes of dissolved organic matter (DOM) after mixing two sets of river waters in Amazon confluences: the Solimoes and Negro Rivers (S + N) and the Amazon and Tapajo s Rivers (A + T). We also studied the effects of water mixing ratios and incubation time on the composition and structure of DOM molecules. NMR spectra demonstrated large-scale structural transformations in the case of S + N mixing, with gain of pure and functionalized aliphatic units and loss of all other structures after 1d incubation. A + T mixing resulted in comparatively minor structural alterations, with a major gain of small aliphatic biomolecular binding motifs. Remarkably, structural alterations from mixing to 1d incubation were in essence reversed from 1d to 5d incubation for both S + N and A + T mixing experiments. Heterotrophic bacterial production (HBP) in endmembers S, N, and S + N mixtures remained near 0.03 mu gC L-1 h(-1), whereas HBP in A, T, and A + T were about five times higher. High rates of dark carbon fixation took place at S + N mixing in particular. In-depth biogeochemical characterization revealed major distinctions between DOM biogeochemical changes and temporal evolution at these key confluence sites within the Amazon basin.
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| 4. |
- Wang, Chunyu, et al.
(författare)
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Co-regulation of temperature and moisture in the irrigated agricultural ecosystem productivity
- 2023
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Ingår i: Agricultural Water Management. - : Elsevier BV. - 0378-3774. ; 275
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Tidskriftsartikel (refereegranskat)abstract
- Agroecosystem photosynthesis is key to coping with global climate change. In farmland where human activities are highly involved, the interaction between environmental factors and their influences on gross primary productivity (GPP) are insufficiently understood. Particularly, the irrigation and mulching in water-saving agriculture can alter the crop responses to environmental change. Based on eddy covariance measurements of maize fields under mulched drip irrigation (DM) and mulched border irrigation (BM) in arid areas of Northwest China from 2014 to 2018, we systematically studied the interaction between multiple environmental factors and their independent effects on GPP using structural equation modeling, partial correlation coefficient and decoupling analysis by bins. The top three factors exerting the largest total effects on the GPP were soil temperature (Ts), canopy temperature (Tc) and vapor pressure deficit (VPD), among which Ts (0.75) and Tc (0.66) had the largest total effect on GPP under DM and BM, respectively. The independent effects of Ts, soil water content (SWC) and VPD on GPP were different under the two irrigation methods. SWC after excluding the influence of Ts showed a negative effect on GPP under DM (−1.24 g Cm−2d−1), while a positive effect under BM (0.02 g Cm−2d−1). By contrast, SWC after excluding the influence of VPD showed a positive effect on GPP under DM (0.59 g Cm−2d−1), while a negative effect under BM (−0.05 g Cm−2d−1). Interestingly, higher Ts, lower SWC and higher VPD had the potential to increase GPP under the two irrigation methods. We also found that the total effects of irrigation and VPD as well as the indirect effects of environmental factors on GPP should not be ignored. Our study will provide important reference for dealing with the effect of high temperature and drought stress on agro-ecosystem GPP and evaluating the response of vegetation to environmental factors.
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| 5. |
- Wang, Chunyu, et al.
(författare)
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Water use efficiency control for a maize field under mulched drip irrigation
- 2023
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697. ; 857
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Tidskriftsartikel (refereegranskat)abstract
- Agricultural ecosystem water use efficiency (WUE) is an important indicator reflecting carbon-water coupling, but its control mechanisms in managed fields remain unclear. In order to reveal the influencing factors of WUE in the agricultural field under mulched drip irrigation (DM), we carried out the 8-year continuous observations in a maize field from Northwestern China. The structural equation model, relative importance analysis and principal component analysis were used to quantify the regulation effects of environmental and biological factors on WUE at different time scales, in different growth stages and under different hydrothermal conditions. The results showed that annual WUE varied between 2.18 g C Kg−1 H2O and 3.60 g C Kg−1 H2O, with a multi-year mean of 2.91 g C Kg−1 H2O. The total effects of air temperature on the daily WUE in the whole growth period, the vegetative growth stage, the warm and dry years, the cold and wet years, and the warm and wet years were the largest, with values of 0.61, 0.80, 0.70, 0.70 and 0.91 respectively. However, vapor pressure deficit and net radiation had the largest total effect in the cold and dry years (−0.63) and the reproductive growth stage (−0.49), respectively. Leaf biomass played a leading role in regulating the daily and interannual WUE, and the relative importance of leaf biomass to WUE in the vegetative growth stage was up to 75 %. In the warm and wet years, the relative importance of root biomass to WUE was 33 %, slightly higher than that of leaf biomass (31 %). At the same time, we found that Ta has the potential to increase WUE under future climate warming. Our results improve the understanding of carbon-water coupling mechanisms and provide important enlightenment on how crop ecosystems should adapt to future climate change.
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| 6. |
- Yang, Danni, et al.
(författare)
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Drip irrigation improves spring wheat water productivity by reducing leaf area while increasing yield
- 2023
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Ingår i: European Journal of Agronomy. - : Elsevier BV. - 1161-0301. ; 143
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Tidskriftsartikel (refereegranskat)abstract
- To mitigate the climate change-induced water shortage and realize the sustainable development of agriculture, drip irrigation, a more efficient water-saving irrigation method, has been intensively implemented in most arid agricultural regions in the world. However, compared to traditional border irrigation, how drip irrigation affects the biophysical conditions in the cropland and how crops physiologically respond to changes in biophysical conditions in terms of water, heat and carbon exchange remain largely unknown. In view of the above situation, to reveal the mechanism of drip irrigation in improving spring wheat water productivity, paired field experiments based on drip irrigation and border irrigation were conducted to extensively monitor water and heat fluxes at a typical spring wheat field (Triticum aestivum L.) in Northwest China during 2017–2020. The results showed that drip irrigation improved yield by 10.3 % and crop water productivity (i.e., yield-to-evapotranspiration-ratio) by 15.6 %, but reduced LAI by 16.9 % in contrast with border irrigation. Under drip irrigation, the lateral development of spring wheat roots was promoted by higher soil temperature combined with frequent dry-wet alternation in the shallow soil layer (0–20 cm), which was the basis for efficient absorption of water and fertilizer, as well as efficient formation of photosynthate. Meanwhile, drip irrigation increased net radiation and decreased latent heat flux by inhibiting leaf growth, thereby increased sensible heat, causing a higher soil temperature (+1.10 ℃) and canopy temperature (+1.11 ℃). Further analysis proved that soil temperature was the key factor affecting yield formation. Based on the above conditions, the decrease in leaf distribution coefficient (−0.030) led to the decrease in evapotranspiration (−5.7 %) and the increase in ear distribution coefficient (+0.029). Therefore, drip irrigation emphasized the role of soil moisture in the soil-plant-atmosphere continuum, enhanced crop activity by increasing field temperature, especially soil temperature, and finally improved yield and water productivity via carbon reallocation. The study revealed the mechanism of drip irrigation for improving spring wheat yield, and would contribute to improving Earth system models in representing agricultural cropland ecosystems with drip irrigation and predicting the subsequent biophysical and biogeochemical feedbacks to climate change.
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