Influence of soil density on gas permeability and water retention in soils amended with in-house produced biochar

Biochar has been used as an environment-friendly enhancer to improve the hydraulic properties(e.g.suction and water retention) of soil.However,variations in densities alter the properties of the soil-biochar mix.Such density variations are observed in agriculture(loosely compacted) and engineering(densely compacted) applications.The influence of biochar amendment on gas permeability of soil has been barely investigated,especially for soil with diffe rent densities.The maj or obj ective of this study is to investigate the water retention capacity,and gas permeability of biochar-amended soil(BAS) with different biochar contents under varying degree of compaction(DOC) conditions.In-house produced novel biochar was mixed with the soil at different amendment rates(i.e.biochar contents of 0%,5% and 10%).All BAS samples were compacted at three DOCs(65%,80% and 95%) in polyvinyl chloride(PVC)tubes.Each soil column was subjected to drying-wetting cycles,during which soil suction,water content,and gas permeability were measured.A simplified theoretical framework for estimating the void ratio of BAS was proposed.The experimental results reveal that the addition of biochar significantly decreased gas permeability k_g as compared with that of bare soil(BS).However,the addition of 5%biochar is found to be optimum in decreasing kg with an increase of DOC(i.e.k_(g,65%) k_(g,80%) k_(g,95%)) at a relatively low suction range(200 kPa) because both biochar and compaction treatment reduce the connected pores.     

基于POI数据的站区商业业态分布研究 ——以武汉三站为例

针对目前铁路站区的商业空间规划与实际开发建设脱节的现状,选取武汉三个铁路站区作为研究案例,从车站周边商业和外围区商业2个圈层对站区商业开发现状进行考察和分析,并总结分析站区商业业态POI数据,归纳得出大型铁路站区商业业态布局特点及规律.     

Feasibility of non-destructive evaluation for apple crispness based on portable acoustic signal

In this paper, apple crispness was evaluated by sensory evaluation and compared with non-destructive measurements of portable acoustic signal to discuss the feasibility of non-destructive evaluation for apple crispness based on portable acoustic signal. Acoustic eigenvalues from the acoustic signal were processed by time domain and Hilbert–Huang transform (HHT), followed by analysing the correlations with apple crispness that had been evaluated via sensory evaluation. Multiple linear regression (MLR) and artificial neural network (ANN) were applied to predict apple crispness. The results proved that crispness correlates significantly (P < 0.01) with four acoustic eigenvalues, including waveform index, sound intensity, energy of low frequency and energy of high frequency. The average relative error of apple crispness predicted by ANN was 1.42 ± 1.9%, remarkably lower (P < 0.01) that of MLR (6.79 ± 5.64%), implying that the model predicted by ANN is more accurate than that of MLR.     

日本被动式租赁住房规划设计研究

文章从项目的缘起、规划设计、思想理念及被动技术等方面对日本优秀被动式租赁住房案例PassiveTown进行分析,进一步了解了日本被动式技术在租赁住房规划设计中的应用.     

The Activity of Small Urea-γ-AApeptides Toward Gram-Positive Bacteria

Host Defense Peptides (HDPs) have gained considerable interest due to the omnipresent threat of bacterial infection as a serious public health concern. However, development of HDPs is impeded by several drawbacks, such as poor selectivity, susceptibility to proteolytic degradation, low-to-moderate activity and requiring complex syntheses. Herein we report a class of lipo-linear α/urea-γ-AApeptides with a hybrid backbone and low molecular weight. The heterogeneous backbone not only enhances chemodiversity, but also shows effective antimicrobial activity against Gram-positive bacteria and is capable of disrupting bacterial membranes and killing bacteria rapidly. Given their low molecular weight and ease of access via facile synthesis, they could be practical antibiotic agents.     

Amine-containing olefin copolymer with CO2-switchable oil absorption and desorption

Global decrease in crude oil resources and frequent crude oil leaks cause the energy crisis and ecological pollution. The absorption and release of leaked crude oil through absorption materials are a necessary process for environmental protection and recycling. In this article, a CO₂-responsive olefin copolymer was obtained by copolymerization of styrene and an amine-containing olefin monomer. The structure of resultant copolymer was characterized by FTIR; thermal properties and CO₂-responsive morphology changes were determined by DSC/TGA and SEM, respectively. Copolymers had certain absorption capacity for toluene with absorption rate up to 180.0%. The absorbed toluene could be released upon CO₂ stimulation with desorption rate up to 84.6%. The CO₂-responsive copolymer could be regenerated through a simple heating process and showed stable absorption–desorption performance even after being recycled for 4 times. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47439.     

The impact of recrystallisation on the freeze-thaw cycles of red seabream (Pagrus major) fillets

Recrystallisation often occurs in the freeze-thaw cycles and results in poor food quality. This study was undertaken to analyse the effects of recrystallisation on the changes of protein conformation and moisture migration within red seabream fillets after the freeze-thaw cycles. The UV second-derivative spectroscopy, intrinsic fluorescence measurement and Raman spectroscopy were employed to evaluate the protein conformational changes. The Low-field NMR spectra analysis was used to evaluate moisture migration. The results indicated that the freeze-thaw cycles altered the secondary and tertiary structure of proteins. It was noticed that interactions between water and protein molecules were decreased gradually and eventually induced the thermal instability of the myosin molecules. The immobilised water content declined and the free water content increased. There were significant destructions in fillet muscle microstructure. These observations unambiguously reflect how the recrystallisations affect the protein conformation and moisture migration patterns of red seabream fillets during freeze-thaw cycles.     

Evolution of oxidative and structural characteristics of proteins,especially lipid transfer protein 1 (LTP1) in beer during forced-ageing

The evolution of oxidative and structural characteristics of proteins, especially lipid transfer protein 1 (LTP1), in beer during forced-ageing was examined. The oxidative characteristics of beer and proteins were evaluated by DPPH radical scavenging activity and ABTS radical cation scavenging activity. Results showed that the levels of proteins, thiols, LTP1 and antioxidant activity decreased gradually. This was accompanied by the degradation of macromolecular proteins in beer during forced-ageing. Results from circular dichroism (CD), Fourier-transform infrared spectroscopy (FTIR), surface hydrophobicity (S₀) and ζ-potential further indicated that the secondary and tertiary structure of LTP1 changed drastically during forced-ageing, with the reduction of the S₀, α-helix and β-sheet contents and the increase in negative ζ-potential and random coil. Thus, the proteins, especially LTP1, might play important roles in maintaining oxidative stability of beer.