Direct incorporation of paraffin wax as phase change material into mass concrete for temperature control: mechanical and thermal properties

Taking advantage of heat absorbing and releasing capability of phase change material(PCM),Paraffin wax-based concrete was prepared to assess its automatic temperature control performance.The mechanical properties of PCM concrete with eight different Paraffin wax contents were tested by the cube compression test and four-point bending test.The more Paraffin wax incorporated,the greater loss of the compressive strength and bending strength.Based on the mechanical results,four contents of Paraffin wax were chosen for studying PCM concrete's thermal properties,including thermal conductivity,thermal diffusivity,specific heat capacity,thermal expansion coefficient and adiabatic temperature rise.When the Paraffin wax content increases from 10%to 20%,the thermal conductivity and the thermal diffusivity decrease from 7.31 kJ/(m·h·°C)to 7.10 kJ/(m·h·°C)and from 3.03×10−3 m2/h to 2.44×10−3 m2/h,respectively.Meanwhile the specific heat capacity and thermal expansion coefficient rise from 5.38×10−1 kJ/(kg·°C)to 5.76×10−1 kJ/(kg·°C)and from 9.63×10−6/°C to 14.02×10−6/°C,respectively.The adiabatic temperature rise is found to decrease with an increasing Paraffin wax content.Considering both the mechanical and thermal properties,15%of Paraffin wax was elected for the mass concrete model test,and the model test results confirm the effect of Paraffin wax in automatic mass concrete temperature control.

An endolysin gene from Candidatus Liberibacter asiaticus confers dual resistance to huanglongbing and citrus canker

The most damaging citrus diseases are Huanglongbing(HLB)and citrus canker,which are caused by Candidatus Liberibacter asiaticus(CaLas)and Xanthomonas citri pv.citri(Xcc),respectively.Endolysins from bacteriophages are a possible option for disease resistance in plant breeding.Here,we report improvement of citrus resistance to HLB and citrus canker using the LasLYS1 and LasLYS2 endolysins from CaLas.LasLYS2 demonstrated bactericidal efficacy against several Rhizobiaceae bacteria and Xcc,according to inhibition zone analyses.The two genes,driven by a strong promoter from Cauliflower mosaic virus,35S,were integrated into Carrizo citrange via Agrobacterium-mediated transformation.More than 2 years of greenhouse testing indicated that LasLYS2 provided substantial and long-lasting resistance to HLB,allowing transgenic plants to retain low CaLas titers and no obvious symptoms while also clearing CaLas from infected plants in the long term.LasLYS2 transgenic plants with improved HLB resistance also showed resistance to Xcc,indicating that LasLYS2 had dual resistance to HLB and citrus canker.A microbiome study of transgenic plants revealed that the endolysins repressed Xanthomonadaceae and Rhizobiaceae populations in roots while increasing Burkholderiaceae and Rhodanobacteraceae populations,which might boost the citrus defense response,according to transcriptome analysis.We also found that Lyz domain 2 is the key bactericidal motif of LasLYS1 and LasLYS2.Four endolysins with potential resistance to HLB and citrus canker were found based on the structures of LasLYS1 and LasLYS2.Overall,the work shed light on the mechanisms of resistance of CaLas-derived endolysins,providing insights for designing endolysins to develop broad-spectrum disease resistance in citrus.

Water-Driven Malleable,Weldable and Eco-Friendly Recyclable Carbon Fiber Reinforced Dynamic Composites

Traditional carbon fiber-reinforced polymers based on thermoset matrix have been extensively used in the fields of wind turbine blades,automotive sector,and aerospace,among many others.However,there is still a major challenge of recycling those polymers due to the high cost and adverse impacts on the environment.In this work,we apply a polyimine network as matrix,which possess considerable tensile and thermal properties,to prepare the carbon fiber reinforced polyimine materials with trifluoromethyl diphenoxybenzene units(CFRFP)using a prepreg-based compression molding method.The CFRFP can be reshaped or reprocessed by heat or with water rapidly,and exhibited multifunction,including welding,chemical recycling,etc.These unique findings gained from our study will facilitate the manufacturing capability and enrich the types of fiber-reinforced composites.

Visible photoluminescence of polyoxoniobates in aqueous solution and their high electrocatalytic activities for water oxidation

The photoluminescence of four polyoxoniobates [Nb6O19]8-, [Nb10O28]6-, [Ti2Nb8O28]8- and [H2Si4Nb16O56]14- was observed, and its origin was revealed in the view of molecular orbital by means of the computational method. The photoluminescence is originated from singlet transitions, and the calculated values agree well with the experimental data. The results indicate that the size of clusters and the foreigner atoms can affect the fluorescent properties of PONbs. The absorption and emission of these PONbs are originated molecular orbitals contributed mainly by μ2-O and Nb atoms according to NBO analysis. These PONbs were also found as electrochemical catalysts with high performance for water oxidation, which can effectively split water into oxygen under basic condition with a high catalytic current, and pH values have remarkable influence on the electrocatalytic activities of these PONbs for water oxidation.

Extractant(2,3-dimethylbutyl)(2,4,40-trimethylpentyl) phosphinic acid(INET-3) impregnated onto XAD-16 and its extraction and separation performance for heavy rare earths from chloride media

（2,3-Dimethylbutyl）（2,4,40-trimethylpentyl）phosphinic acid（INET-3） was impregnated onto dry macroporous resins XAD-16 and pretreated XAD-16 with ethyl alcohol and HCl（Pre-XAD-16） to prepare the solvent impregnated resins SIRs-INET-3/XAD-16 and SIRs-INET-3/Pre-XAD-16. The molecular weight distribution of the low molecular weight（LMW） polymers washed off by ethyl alcohol during XAD-16 pretreatment was determined by gel permeation chromatography（GPC）. The macroporous resins（XAD-16 ＆ Pre-XAD-16）, the corresponding solvent impregnated resins（SIRs-INET-3/XAD-16 ＆SIRs-INET-3/Pre-XAD-16） and the PVA coated SIRs-INET-3/Pre-XAD-16 with boric acid as cross-linking agent were characterized by FT-IR, SEM-EDS and TGA. The effects of XAD-16 pretreatment and PVA coating technology on RE（III） adsorption equilibrium time, INET-3 losses during extraction and adsorption capacity were investigated. The adsorption kinetics, selectivity and stripping behaviors of SIRs-INET-3/XAD-16 were further studied. The washed off LMW polymers had the Mn of 36,656, Mw of 40,310 and polydispersity coefficient of 1.10. The SIRs-INET-3/XAD-16 had shorter equilibrium time,less INET-3 loss and more Tm（III） adsorption capacity than the SIRs-INET-3/Pre-XAD-16. The PVA coated SIRs-INET-3/Pre-XAD-16 had less INET-3 loss and more Tm（III） adsorption capacity but longer equilibrium time than the uncoated SIRs-INET-3/Pre-XAD-16. The adsorption of RE（III） on the SIRsINET-3/XAD-16 followed the pseudo-second-order kinetic model. The Tm（III） accumulative adsorption amounts onto SIRs-INET-3/XAD-16 after eight extraction stages was 23.6 mg/g. The separation factors of adjacent heavy RE（III） β（Er/Ho）, β（Tm/Er）, β（Yb/Tm） and β（Lu/Yb） values were 1.76, 2.59, 2.56 and 1.19,respectively. The adsorbed Lu（III） onto the SIRs-INET-3/XAD-16 can be stripped completely by 1.0 mol/L H2SO4.

Application of a Nanostructured Composite Material Constructed by Self-Assembly of Titanoniobate Nanosheets and Cobalt Porphyrin to Electrocatalytic Reduction of Oxygen

A novel layered nanocomposite was fabricated by the self-assembly of TiNbOs-nanosheets and 5,10,15,20- tetrakis（N-methylpyridinium-4-yl）porphyrinatocobalt（III） （CoTMPyP）. The product was characterized by a variety of analytical techniques such as XRD, EDX, Zeta potential, AFM, UV-vis, IR and SEM, the guest species were intercalated into the interlayer gallery of KTiNbO5 successfully. The electrochemical property of TiNbO5-CoTMPyP as an electrode modifying material was examined by cyclic voltammetry test in PBS solution （pH = 7）, and the hybrid exhibited excellent electrocatalytical property towards oxygen reduction with the peak potential shifting from -0.703 V （bare GCE） to -0.278 V （modified electrode）. The result also indicated that the oxygen molecule was reduced to H2O2 by a two-electron process.

Function and molecular mechanism analysis of CaLasSDE460 effector involved in the pathogenesis of“Candidatus Liberibacter asiaticus”in citrus

Citrus Huanglongbing(HLB),caused by Candidatus Liberibacter asiaticus(CaLas),is the most serious disease worldwide.CaLasSDE460 was previously characterized as a potential virulence factor of CaLas.However,the function and mechanism of CaLasSDE460 involved in CaLas against citrus is still elusive.Here,we showed that transgenic expression of CaLasSDE460 in Wanjincheng oranges(C.sinensis Osbeck)contributed to the early growth of CaLas and the development of symptoms.When the temperature increased from 25℃to 32℃,CaLas growth and symptom development in transgenic plants were slower than those in WT controls.RNA-seq analysis of transgenic plants showed that CaLasSDE460 affected multiple biological processes.At 25℃,transcription activities of the“Protein processing in endoplasmic reticulum”and“Cyanoamino acid metabolism”pathways increased while transcription activities of many pathways decreased at 32℃.124 and 53 genes,separately annotated to plant-pathogen interaction and MAPK signaling pathways,showed decreased expression at 32℃,compared with these(38 for plant-pathogen interaction and 17 for MAPK signaling)at 25℃.Several important genes(MAPKKK14,HSP70b,NCED3 and WRKY33),remarkably affected by CaLasSDE460,were identified.Totally,our data suggested that CaLasSDE460 participated in the pathogenesis of CaLas through interfering transcription activities of citrus defense response and this interfering was temperature-dependent.

Modelling soil water dynamics and root water uptake for apple trees under water storage pit irrigation

Water storage pit irrigation is a new method suitable for apple trees.It comes with advantages such as water saving,water retention and drought resistance.A precise study of soil water movement and root water uptake is essential to analyse and show the advantages of the method.In this study,a mathematical model(WSPI-WR model)for 3D soil water movement and root water uptake under water storage pit irrigation was established based on soil water dynamics and soil moisture and root distributions.Moreover,this model also considers the soil evaporation,pit wall evaporation and water level variation in the pit.The finite element method was used to solve the model,and the law of mass conservation was used to analyse the water level variation.The model was validated by experimental data of the sap flow of apple trees and soil moisture in the orchard.Results showed that the WSPI-WR model is highly accurate in simulating the root water uptake and soil water distributions.The WSPI-WR model can be used to simulate root water uptake and soil water movement under water storage pit irrigation.The simulation showed that orchard soil water content and root water uptake rate centers on the storage pit with an ellipsoid distribution.The maximum distribution region of soil water and root water uptake rate was near the bottom of the pit.Distribution can reduce soil evaporation in the orchard and improve the soil water use efficiency in the middle-deep soil.

Urease activity and urea hydrolysis rate under coupling effects of moisture content,temperature,and nitrogen application rate

The traditional qualitative analysis of the individual factors on the kinetic parameters cannot sufficiently reveal the mechanism underlying urea hydrolysis in soil.This study aimed at revealing the coupling effects of the three factors on urease activity(V_(0)),hydrolysis rate constant(K_(u)),and activation energy(Ea)and establishing the quantitative model for K_(u) under the coupling condition.Laboratory culture experiments were conducted under different temperatures(T)(15℃,20℃,25℃,and 35℃),moisture contents(θ)(60%,80%,and 100%of field capacities),and nitrogen application rates(F)(247 mg/kg,309 mg/kg,371 mg/kg,and 433 mg/kg).The urea content was measured daily.Results showed that the effects of moisture content,temperature,nitrogen application rate,and their interaction on V_(0) and K_(u) were in the descending order:T,F,T^(*)F,θ,T^(*)θ,F^(*)θ,T^(*)θ^(*)F.The effect of single factor and two-factor coupling on V_(0) was extremely significant(p<0.01),whereas the effect of the three-factor coupling on V_(0) was negligible.The effects of three factors and their interaction on K_(u) were extremely significant(p<0.01).The effects of moisture content,nitrogen application rate,and their interaction on Ea were in the descending order:F,θ,F^(*)θ.The effects of two factors and their interaction on Ea were not significant.The mean absolute percentage error(MAPE)values of the established K_(u-1)(θ,T,F)and K_(u-2)(θ,T,F)models were 3.14%and 4.60%,respectively.The MAPE of the traditional Arrhenius model K_(u-3)(T)was 6.75%.The accuracy of the proposed three-factor interaction model was superior to that of the traditional single factor model.The results supplemented the mechanism of urea hydrolysis and improved the prediction accuracy of K_(u).