低质水的价格理论与实践

低质水就是现代城市建设中促进水资源高效利用的新产物,它是指将未经处理或简单处理的原水、中水系统的回用水等低品质水作为初级非饮用水,单设管网供应,用于冲洗厕所、园林绿化、清洗车辆、喷洒道路、景观用水等。低质水系统通常是局部或区域性的,在节约水资源和降低水处理费用等方面存在优势。本文针对低质水的价格进行了理论和实践上的探讨。

东丰县城区低质水利用模式研究

水资源短缺是制约我国乃至全球城市发展的主要因素之一,在此背景下开展水资源合理利用是解决水危机的关键措施,而低质水利用是水资源合理利用的重要途径和方向。本文以东丰县研究实例,结合东丰县水资源情况,对城市低质水利用模式进行的深入研究。

直接进样-全反射X射线荧光光谱快速测定饮用水微量元素

相比于复杂的富集程序,饮用水中由于金属元素含量甚微,急需一种快速,简单和可靠的检测方法。全反射X射线荧光光谱法(TXRF)是一种方便快捷、定量简单的微量多元素同步分析方法,该方法所需要的样品少,测量时间短,无需预处理可实现对样品的直接分析。以镓(Ga)为内标,采用直接进样-TXRF法,探究了快速测定多质量浓度梯度多元素金属溶液的可行性,并将该方法应用于低矿物质饮用水中进行微量元素分析。实验结果表明,TXRF能直接提取溶液中的Al、K、Ca、Mn、Fe、Co、Ni、Cu、Zn、Sr进行同步测量,但是多次试验发现,Al、K、Ca作为轻质元素由于回收率明显偏离标准值,难以实现准确定量,究其原因是基体效应较大或元素的灵敏度较低,而其他元素均满足定量要求。通过对不同浓度梯度的标准样品进行测量,发现当金属元素浓度分别处于40 mg·L^(-1)、4 mg·L^(-1)、0.4 mg·L^(-1)、40μg·L^(-1)水平时,Mn、Fe、Co、Ni、Cu、Zn、Sr元素均呈现出很好的准确度和精密度,回收率(RR)稳定在80%~112%,相对标准偏差(RSD)处于3.6%~10.5%,检出限(DL)处于0.001~0.07 mg·L^(-1)。随着浓度梯度的逐渐下降,各元素的准确度和精密度开始表现出不同程度的下降,当质量浓度处于本文试验最低水平4μg·L^(-1)时,大部分元素(Mn除外)的回收率和RSD均明显偏离标准值。还利用直接进样-TXRF法,在低、中、高三个不同加标水平下对饮用矿物质水进行加标回收试验,结果表明,样本中Mn、Fe、Co、Ni、Cu、Zn、Sr元素含量基本处于几十个μg·L^(-1)水平,平均加标回收率在90%~110%之间,平均RSD小于12%,满足微量测定要求。综上所述,多元素测试结果表明,TXRF在对元素的选择上更适宜原子序数(Z>20)的中等重元素,对于组分含量在十几个μg·L^(-1)以上的水质样品,无需经过复杂预处理,可直接实现快速准确定量分析,对于环境中的超痕量样品需要使用预浓缩技术以提高测量准确率。

Changes in Violaxanthin Deepoxidase Activity and Unsaturation of Thylakoid Membrane Lipids in Indica and Japonica Rice Under Chilling Condition and Strong Light

To explore the differences of sensitivities to chilling and strong light in indica and japonica rice (Oryza sativa L), the changes in unsaturation of thylakoid membrane lipids and xanthophyll cycle were studied under chilling condition and strong light. The contents of unsaturated fatty acids of thylakoid membrane lipids decreased and that of the saturated ones increased with the time of chilling and strong light treatment, resulting in the reduction of the index of unsaturation of fatty acids (IUFA). The activity of violaxanthin deepoxidase (VDE), a key enzyme of xanthophyll cycle, also reduced. The content of violaxanthin (V) increased, and the contents of antheraxanthin (A) and zeaxanthin M decreased, the ratio of (A+Z)/ (A+Z+V) decreased correspondingly. Arrhenius analysis showed that VDE was sensitive to both chilling and unsaturation level of thylakoid membrane lipids. Correlation analysis showed that there was distinctly positive relationships between IUFA of thylakoid membrane lipids and the activity of VDE, Fv/Fm, and D, protein content. Lower IUFA values, less fluidity and stability of thylakoid membrane lipids, lower VDE activity and (A+Z)/(A+Z+V) ratio were found in indica rice cv. Shanyou 63 than in japonica rice cv. 9516 under chilling and strong light.

Effect of coal moisture content on coke’s quality and yields of products during coal carbonization

The coal with low moisture during carbonization could not only increase the yield of coke,but also promote the coke quality and reduce the energy consumption.In this paper,the influence of the moisture in the blend coal(1.8%10.13%)on the product yields and coke quality during coal carbonization were investigated.The results show that the coke yield is increased from 75.90%to 77.16%,and the coke qualities such as coke strength after reaction with CO2(CSR),coke reactivity index(CRI),fragmentation index(M25)and abrasion index(M10))are also improved when the moisture of the blend coal decreases from 10.13%to 1.80%in a bench scale reactor.Due to the secondary reaction,tar become lighter when the moisture is decreased.In order to further prove the above results,the blend coal with 1.8%and 9%10%(common moisture used in coke plant)moisture is carbonized in a coke oven with 6 m height,the results show that CRI are 23.4%and 27.3%,CRS are 67.1%and 62.2%under 1.8%and 9%10%moisture of blend coal.Moreover,the variation of the moisture in blend coal has a limited influence on dust emission at the ascension pipe and the charging car.

Upland rice and lowland rice exhibited different P/P expression under water deficit and ABA treatment

Aquaporins play a significant role in plant water relations. To further understand the aquaporin function in plants under water stress, the expression of a subgroup of aquaporins, plasma membrane intrinsic proteins （PIPs）, was studied at both the protein and mRNA level in upland rice （Oryza sativa L. cv. Zhonghan 3） and lowland rice （Oryza sativa L. cv. Xiushui 63） when they were water stressed by treatment with 20% polyethylene glycol （PEG）. Plants responded differently to 20% PEG treatment. Leaf water content of upland rice leaves was reduced rapidly. PIP protein level increased markedly in roots of both types, but only in leaves of upland rice after 10 h of PEG treatment. At the mRNA level, OsPIP1,2, OsPIP1,3, OsPIP2;1 and OsPIP2;5 in roots as well as OsPIP1,2 and OsPIP1;3 in leaves were significantly up-regulated in upland rice, whereas the corresponding genes remained unchanged or down-regulated in lowland rice. Meanwhile, we observed a significant increase in the endogenous abscisic acid （ABA） level in upland rice but not in lowland rice under water deficit. Treatment with 60 μM ABA enhanced the expression of OsPIP1;2, OsPIP2;5 and OsPIP2;6 in roots and OsPIP1;2, OsPIP2;4 and OsPIP2;6 in leaves of upland rice. The responsiveness of PIP genes to water stress and ABA were different, implying that the regulation of PIP genes involves both ABA-dependent and ABA-independent signaling oathways during water deficit.

Relationship Between Soil and Water Conservation Practices and Soil Conditions in Low Mountain and Hilly Region of Northeast China

The soil and water conservation practices of ecological restoration(ER),fish scale pit(FP),furrow and ridge tillage across the slope(FR),shrub strips(SS),and vegetation-covered ridge(VR)are characteristic of the Jixing small watershed of the low mountain and hilly region of Jilin Province,Northeast China.This study aims to elucidate the effects of soil and water conservation practices on soil conditions after the short-term implementation of practices.Soil samples were collected from five soil and water conservation sites(ER,FP,FR,SS,and VR)and two controls(BL and CT)to investigate their properties.To evaluate the influence of soil and water conservation practices on soil quality,an integrated quantitative index,soil quality index(QI),was developed to compare the soil quality under the different soil and water conservation practices.The results show that not all soil and water conservation practices can improve the soil conditions and not all soil properties,especially soil organic carbon(SOC),can be recovered under soil and water conservation practice in short-term.Moreover,the QI in the five soil and water conservation practices and two controls was in the following order:ER>VR>BL>FR>CT>SS>FP.ER exhibited a higher soil quality value on a slope scale.In the low mountain and hilly region of Northeast China,ER is a better choice than the conversion of farmlands to planted grasslands and woodlands early in the soil and water conservation program.

Hydration mechanism of low quality fly ash in cement-based materials

The hydration mechanism of low quality fly ash in cement-based materials was investigated. The hydration heat of the composite cementitious materials was determined by isothermal calorimetry, and the hydration products, quantity, pore structure and morphology were measured by X-ray diffraction(XRD), thermalgravity-differential thermal analysis(TG-DTA), mercury intrusion porosimetry(MIP) and scanning electron microscopy(SEM), respectively. The results indicate that grinding could not only improve the physical properties of the low quality fly ash on particle effect, but also improve hydration properties of the cementitious system from various aspects compared with raw low quality fly ash(RLFA). At the early stage of hydration, the low quanlity fly ash acts as almost inert material; but then at the later stage, high chemical activity, especially for ground low quality fly ash(GLFA), could be observed. It can accelerate the formation of hydration products containing more chemical bonded water, resulting in higher degree of cement hydration, thus denser microstructure and more reasonable pore size distribution, but the hydration heat in total is reduced. It can also delay the induction period, but the accelerating period is shortened and there is little influence on the second exothermic peak.

Wastewater treatment performance and microbial community structure in the constructed wetland under double-pressure of low temperature and Ag NPs exposure

To investigate the effects of silver nanoparticles(Ag NPs)and low temperature double-pressure on the wastewater treatment efficacy and the microbial community structure of constructed wetlands,a pilot-scale vertical flow constructed wetland was set up to treat synthetic wastewater under laboratory conditions.By measuring the effluent concentration of ammonia nitrogen(NH_(4)^(+)-N),total nitrogen(TN),total phosphorus(TP),chemical oxygen demand(COD),and the diversity,richness,and community structure of microorganisms of the upper and lower soil layers in the wetland,the nutrient removal effect of the constructed wetland and the changes in the microflora of the soil layer were studied.The results reveal that the correlation coefficients between the removal rates of TN and NH_(4)^(+)-N and the temperature are 0.463 and 0.692,respectively,indicating a significant positive correlation.From the warm to the cold season,both the diversity and richness of microorganisms in the lower soil layer of wetlands are inhibited under the double-pressure of Ag NPs and low temperature,and the abundances of the denitrogenation functional bacteria such as Candidatus nitrososphaera,Sulfuritalea,Anaeromyxobacter,Candidatus solibacter,Nitrospira,and Zoogloea are altered.Low temperature and Ag NPs exposure can thus affect the wastewater treatment performance of constructed wetlands,possibly because of the seasonal changes of the microflora.

The Hydrolyzation of Collagen by Fucoidan Olisosaccharide's Complex with Ce^(IV)

Fucoidan is such a polysaccharide that its hydroxies are easy to combine with lanthanons ion （Ce^IV） to form complex. This work obtained the complexes of three fucoidan oligosaccharides with different molecular weights F1 （〉5 000）, F2 （1 000-5 000） and F3 （〈 1 000） by hydrolyzing Oligosaccharide collagen with sulfuric acid. It is found that the fucoidan oligosaccharide F3 can form complex with more Ce^IV than F1 and F2. Hydrolyzing collagen with the complex was carried out to produce amino acid and peptides. All the three fucoidan oligosaccharide complexes with CeIV（ F1, F2, F3） can catalyze by the artificial hydrolytic enzyme, and the activity of the complex of F3 is the highest.

Utilization of low quality water of mountain reservoirs: a case study from Al Jabal Al Akhdar, Oman

Al Jabal al Akhdar(Green Mountain) in arid northern Oman has freshwater resources that had supported small communities for hundreds of years. Jabal Akhdar receives more rainfall(300-400 mm) when compared to the desert plains. In the last few years, this region had undergone enormous changes due to rapid development. The resident and transient populations have increased and their activities exert severe stress on the water resources. There are 24 retention reservoirs in the area, but most are eutrophic and the nutrient loading is due to input of animal fecal matter via surface run-off. As expected, these waters contaminated with coliform bacteria and some have pathogenic Escherichia coli. Drinking water needs of all the villages met by groundwater extraction. Because of poor quality, the surface water in the reservoirs is under-utilized. A low-cost lowmaintenance treatment system designed, constructed and operated in one village to clean the reservoir water for non-drinking human use. The treatment unit improved the water quality parameters. A survey among the adult male population of the village showed their eagerness to adopt this system and use the treated reservoir water for uses other than agriculture. Establishment of these treatment units in other villages should reduce the pressures on groundwater extraction.

Effects of Fungicide Treatments and Storage Temperatures on Fruit Quality of Two Mango （Mangifera indica） Cultivars

Harvested fruits of mango （Mangifera indica） suffer from both physiological and pathological deterioration in quality during storage which consequently affects their market value. A study was conducted to investigate the effects of fungicide treatments and storage temperatures on fruit quality of two mango cultivars, Keirt and Palmer. Mango fruits were treated with 0.04% or 0.08% v/v Triadimefon at either 53 ℃ （hot） or at room temperature and then either stored under ambient conditions （27-29 ℃） or in a refrigerator at a temperature of 11-12 ℃. Fruits stored under ambient conditions developed external colour faster than those stored at a lower temperature. Brix values for fruits treated with Triadimefon decreased with time. Fruits stored at lower temperatures gave least Brix values as compared with those stored under ambient conditions. Percentage titratable acid （%TA） of fruits stored at low temperatures increased over time. Fruits stored at lower temperatures recorded lower pH compared with fruits stored under ambient conditions. Palmer fruits recorded higher %Brix to %TA ratio, indicating a higher sweetness level. The firmness of Palmer fruits kept at lower temperatures increased with time when compared with Keitt fruit. Fruits treated with hot water at 53 ℃ and/or stored at low temperatures （11-12 ℃） had lower levels of anthracnose infection than other treatments. Keitt fruits were more susceptible to anthracnose infection than Palmer fruits. Mango fruits should therefore be treated with hot water at 53 ℃ and then stored at low temperatures （11-12 ℃） in order to slow down the rate of ripening and to reduce anthracnose infection.

First dark matter search results from the PandaX-Ⅰ experiment

We report on the first dark-matter(DM)search results from PandaX-I,a low threshold dual-phase xenon experiment operating at the China JinPing Underground Laboratory.In the 37-kg liquid xenon target with 17.4 live-days of exposure,no DM particle candidate event was found.This result sets a stringent limit for low-mass DM particles and disfavors the interpretation of previously-reported positive experimental results.The minimum upper limit,3.7×10-44cm2,for the spin-independent isoscalar DM-particle-nucleon scattering cross section is obtained at a DM-particle mass of 49 GeV/c2at 90%confidence level.

Recyclable nanocellulose-confined palladium nanoparticles with enhanced room-temperature catalytic activity and chemoselectivity

We describe the synthesis of even-dispersed palladium nanoparticles(Pd NPs)confined within a cellulose nanofiber(CNF)matrix for developing a high-performance and recyclable catalyst.The CNF matrix was composed of CNF-assembled mesoporous nanosheets and appeared as soft and hydrophilic foam.Ultrafine Pd NPs(∼6 nm)with high-loading(9.6 wt%)were in situ grown on these mesoporous nanosheets,and their dense spatial distributions were likely to generate nano-confinement catalytic effects on the reactants.Consequently,the CNF-confined Pd NPs(CNF-Pd)exhibited an enhanced room-temperature catalytic activity on the model reaction of 4-nitrophenol hydrogenation with a highest rate constant of 8.8×10^−3 s^−1 and turnover frequency of 2640 h The CNF Pd catalyst possessed good chemical stability and recyclability in aqueous media which could be reused for at least six cycles without losing activity.Moreover,chemoselective reduction of 3 nitrostyrene was achieved with high yield(80%–98%)of 3-aminostyrene in alcohol/water cosolvent.Overall,this work demonstrates a positive nanoconfinement effect of CNFs for developing stable and recyclable metal NP catalysts.

New insights into the effects of molecular weight and end group on the temperature-induced phase transition of poly(N-isopropylacrylamide) in water

In an attempt to clarify issues related to the molecular weight dependence of the phase transition of poly(N-isopropylacrylamide) (PNIPAM) in water,we prepared a library of PNIPAM samples of well-controlled molecular weight (7000 to 45000 g/mol) bearing identical groups on each chain end.The polymers were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization of N-isopropylacrylamide (NIPAM) with a bifunctional chain tranfer agent and further end group modification.The effects of the end group chemical structure,hydroxyethyl (HE),propargyl (Pr),chloroethyl (CE),n-butyl (nBu),n-hexyl (nHe),and isobutylsulfanylthiosulfanyl (IBS) on the phase transition temperature of aqueous PNIPAM solutions were investigated by high-sensitivity differential scanning calorimetry (HS-DSC),yielding the enthalpy ΔH and the endotherm maximum temperature (T M),and turbidimetry,providing the cloud point (T CP) of each solution.The T CP and T M of the PNIPAM sample of lowest molar mass (M n 7,000 g/mol,0.5 g/L) ranged,respectively,from 38.8 to 22.5 °C and 42.2 to 26.0 °C,depending on the structure of the end-group,whereas H showed no strong end-group dependence.The phase transition of all polymers,except,-di(n-butyl-PNIPAM),exhibited a marked dependence on the polymer molar mass.

Bidirectional regulation of fragile X mental retardation protein phosphorylation controls rhodopsin hornoeostasis

Homoeostatic regulation of the light sensor, rhodopsin, is critical for the maintenance of light sensitivity and survival of photore- ceptors. The major fly rhodopsin, Rhl, undergoes light-induced endocytosis and degradation, but its protein and mRNA levels remain constant during light/dark cycles. It is not clear how translation of Rhl is regulated. Here, we show that adult photorecep- tors maintain a constant, abundant quantity of ninaE mRNA, which encodes Rhl. We demonstrate that the Fmrl protein associ- ates with ninaE mRNA and represses its translation. Further, light exposure triggers a calcium-dependent dephosphorylation of Fmrl, which relieves suppression of Rhl translation. We demonstrate that Mts, the catalytic subunit of protein phosphatase 2A （PP2A）, mediates light-induced Fmrl dephosphorylation in a regulatory B subunit of PP2A （CKa）-dependent manner. Finally, we show that blocking light-induced Rhl translation results in reduced light sensitivity. Our results reveal the molecular mechanism of Rhl homoeostasis and physiological consequence of Rhl dysregulation.