Modeling surface water-groundwater interaction in arid and semi-arid regions with intensive agriculture

In semi-arid and arid areas with intensive agriculture, surface water-groundwater (SW-GW) interaction and agricultural water use are two critical and closely interrelated hydrological processes. However, the impact of agricultural water use on the hydrologic cycle has been rarely explored by integrated SW-GW modeling, especially in large basins. This study coupled the Storm Water Management Model (SWMM), which is able to simulate highly engineered flow systems, with the Coupled Ground-Water and Surface-Water Flow Model (GSFLOW). The new model was applied to study the hydrologic cycle of the Zhangye Basin, northwest China, a typical arid to semi-arid area with significant irrigation. After the successful calibration, the model produced a holistic view of the hydrological cycle impact by the agricultural water use, and generated insights into the spatial and temporal patterns of the SW-GW interaction in the study area. Different water resources management scenarios were also evaluated via the modeling. The results showed that if the irrigation demand continuous to increase, the current management strategy would lead to acceleration of the groundwater depletion, and therefore introduce ecological problems to this basin. Overall, this study demonstrated the applicability of the new model and its value to the water resources management in arid and semi-arid areas.     

尾菜有机肥对土壤肥力及圆白菜和小茴香产量和品质的影响

目的 研究尾菜有机肥对土壤肥力及圆白菜和小茴香的产量与品质的影响。方法 采用不同量尾菜有机肥和商品有机肥对比的方法研究尾菜有机肥对土壤及蔬菜的影响。 结果 尾菜有机肥能提升土壤碱解氮、速效磷和速效钾含量,与CK差异达显著水平;与CK相比,施用尾菜有机肥后,圆白菜增产幅度为5.51%~19.74%,小茴香为6.20%~14.84%。结论 确定了尾菜有机肥用量的适宜用量为每公顷使用45吨尾菜有机肥,为蔬菜尾菜资源化利用提供理论依据。     

SAHA-based novel HDAC inhibitor design by core hopping method

The catalytic activity of the histone deacetylase (HDAC) is directly relevant to the pathogenesis of cancer, and HDAC inhibitors represented a promising strategy for cancer therapy. SAHA (suberoanilide hydroxamic acid), an effective HDAC inhibitor, is an anti-cancer agent against T-cell lymphoma. However, SAHA has adverse effects such as poor pharmacokinetic properties and severe toxicities in clinical use. In order to identify better HDAC inhibitors, a compound database was established by core hopping of SAHA, which was then docked into HDAC-8 (PDB ID: 1T69) active site to select a number of candidates with higher docking score and better interaction with catalytic zinc ion. Further ADMET prediction was done to give ten compounds. Molecular dynamics simulation of the representative compound 101 was performed to study the stability of HDAC8-inhibitor system. This work provided an approach to design novel high-efficiency HDAC inhibitors with better ADMET properties.     

Synthesis and characterization of polyaniline–maleic acid salt

Polyaniline–maleic acid (PANI–MAc) salts have been prepared at various maleic acid concentrations. The salts are characterized by using infrared (IR), UV/VIS Spectroscopy, thermogravimetric analysis and conductivity measurements. Blends of PANI–MAc were made with styrene–butyl acrylate (ST–BuA) copolymer and percolation threshold determined.     

Retreat from Salix—Swedish experience with energy crops in the 1990s

A wave of Salix (willow) planting rolled over Sweden in the early 1990s, driven by subsidies and optimistic market expectations. The expected economic life span of such investments is 20 years or more. But in fact, many plantations were terminated or reduced much sooner. This article explores the reasons for this retreat. In a survey to Salix farmers, 41 per cent either have retreated or regretted starting at all. The reasons given are mostly agronomic, rather than economic. In particular, many farmers had planted on low-quality lands, ignoring best-practice advice. Policies in support of energy crops have been volatile and badly designed, in the sense of giving incentives to such reckless plantings, rather than promoting good farm management. Prices for wood chips have also been disappointing, but few farmers cite this as a key reason for termination or regrets.     

Effect of ammonia concentration on hythane (H2 and CH4) production in two-phase anaerobic digestion

Co-production of hydrogen and methane by two-phase anaerobic digestion (AD) may offer a sustainable solution for the centralized treatment of food waste (FW), while ammonia accumulation is potentially encountered. A mesophilic two-phase AD was investigated for hydrogen and methane production from FW at varying ammonia concentrations. The process achieved a hydrogen yield of 47.7 mL/g VS and a methane yield of 335 mL/g VS by optimizing the organic loading rate (OLR) and recirculation ratio. Total ammonia nitrogen (TAN) concentration of 4044 mg/L corresponded to a threshold in the hydrogen reactor, above which ammonia would initiate inhibition of hydrogenogenesis and acidogenesis. Methane yield was recovered in the methane reactor after acute inhibiting effects of TAN below 5800 mg/L, while TAN above 6200 mg/L caused chronic inhibition of methanogens. Adjusting hydraulic retention time (HRT) and recirculation ratio in hydrogen and methane reactors reduced TAN to 960 and 2105 mg/L respectively, resulting in successful recovery was achieved in the hydrogen reactor but not in the methane reactor. The two-phase AD for methane and hydrogen production can be a promising solution for ammonia accumulation in AD from FW.     

The oxidative transformation of sodium arsenite at the interface of α-MnO2 and water

Arsenite is acute contaminant to human health in soil and water environment. In this study, Pyrolusite (α-MnO₂) was used to investigate the oxidative transformation of arsenite into arsenate with batch experiments under different reaction conditions. The results showed that arsenite transformation occurred and was accompanied by the adsorption and fixation of both As(III) and As(V) on α-MnO₂. About 90% of sodium arsenite (10 mg/L) were transformed by α-MnO₂ under the conditions of 25 °C and pH 6.0, 36.6% of which was adsorbed and 28.9% fixed by α-MnO₂. Increased α-MnO₂ dosages promoted As (III) transformation rate and adsorption of arsenic species. The transformation rate and adsorption of arsenic species raised with increasing pH values of reaction solution from 4.7 to 8.0. The oxidation rate decreased and adsorbed As(III) and As(V) increased with increasing initial arsenite concentration. The enhancement on oxidative transformation of sodium arsenite may result from abundant active sites of α-MnO₂. Along with adsorption and fixation of arsenic species during the reaction, the crystal structure of α-MnO₂ did not change, but the surface turned petty and loosen. Our results demonstrated that α-MnO₂ has important potential in arsenic transformation and removal as the environmentally friendly natural oxidant in soil and surface water.     

The properties of pellets from mixing bamboo and rice straw

Rice straw pellets are the main type of biomass solid fuel and have great potential as a bioenergy resource of the future in China. But it also showed important problems because of its high content of ashes and its low gross calorific value, reducing the possibility to be used in domestic heating. It was certified that mixing different types of biomass materials was helpful to improve the properties of pellets. To improve properties of rice straw pellets and investigate the effect of mixing bamboo and rice straw on the pellet properties, some properties of pellets, manufactured using different mixing ratio of bamboo and rice straw particles, were determined in this research. It can be concluded from this research that physical properties of all pellets meet the requirements of Pellet Fuels Institute Standard Specification for Residential/Commercial Densified except for bulk density of pellets, manufactured using mixing ratio (≤3:2) of bamboo and rice straw. The inorganic ash and gross calorific value of rice straw pellets cannot meet the requirement of Pellet Fuels Institute Standard Specification for Residential/Commercial Densified (8.0%) and the minimum requirement for making commercial pellets of DIN 51731 (>17,500 J/g). Both properties are improved through mixing bamboo particles and rice straw particles. It is significant that inorganic ash content and gross calorific value of pellets, manufactured using mixing ratio (≥3:2) of bamboo and rice straw, were lower than 8.0% and higher than 17,500 J/g, respectively. This also shows that mixing different biomass materials is an effective way to optimize properties of biomass solid fuel. All pellets after improvement are proposed as biomass solid fuel and have the potential to be developed as commercial pellets on an industrial scale in China.     

Dehydration of fructose into 5-hydroxymethylfurfural in the presence of ionic liquids

The acid-catalyzed dehydration of fructose was performed in a microbatch reactor at 80 °C using two commercially available ionic liquids, a hydrophilic one, 1-butyl 3-methyl imidazolium tetrafluoroborate (BMIM⁺BF₄⁻), and a hydrophobic one, 1-butyl 3-methyl imidazolium hexafluorophosphate (BMIM⁺PF₆⁻). When the reaction is carried out in 1-butyl 3-methyl imidazolium tetrafluoroborate as solvent and Amberlyst-15 as catalyst, a yield up to 50% in 5-hydroxymethylfurfural (HMF) is obtained within around 3 h. When the reaction is carried out now in 1-butyl 3-methyl imidazolium tetrafluoroborate and in 1-butyl 3-methyl imidazolium hexafluorophosphate as solvents and Amberlyst-15 as catalyst, DMSO is used as a co-solvent, in order, in particular, to solubilize fructose in the hydrophobic ionic liquid. Under these conditions, both ionic liquids allow the reaction to work more rapidly than in DMSO alone and with yields in HMF close to 80% within 24 h.