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It is well-known that reservoir hydrocarbon fluids contain heavy paraffins that may form solid phases of wax at low temperatures. Problems associated with wax formation and deposition are a major c...

A modified cubic-plus-association (CPA) equation of state is presented by considering the influences of pore sizes and intermolecular interactions. Additionally, the van der Waals (vdW) mixing rule is modified to make it applicable to predicting the phase behavior of mixtures. The predictions of the CPA–vdW model are consistent with the experimental interfacial tensions of the CH4-nC10, CO2-nC10, and N2-nC10 systems in nanopores. The predictions of the CPA–vdW model for vapor–liquid equilibria of the CO2-H2O, CH4-H2O, CO2-CH4, and H2O-CH4-CO2 systems are accurate in bulk at 273.15–513.15 K and 0.1–200 MPa. The forward and backward multiple-contact processes are used to model CO2 injection to extract the dissolved CH4. The CH4 recovery factor obtained by CO2 injection is approximately 20%–60% at 273.15–523.15 K and 20–140 MPa only under the equilibrium condition, while flow is not considered.

Throughout todays society, with the further development of economic globalization, public buildings in large space present the tendance of multi-direction and diversification, among all the public buildings in large space, the principles of eco-designing strategy are quite special. On the basic of principles of eco-designing, the author analyses the strategy of eco-designing through some examples. The author presents his opinion mainly from four aspects: smart usage of underground spaces, perfect integration with environment, active adoption of eco-construction, initiative expansion of the green energy, finally, the author tries to come up with the design pattern to summarize the main eco-design strategies of public buildings in large space.

In order to strengthen the high-speed maglev trains anti-disturbance ability, the traditional linear cascade control algorithm has been improved. Firstly, the mathematical model of the joint-structure in the high-speed maglev train was established according to the dynamics and electromagnetism theory.Secondly,the advantages and disadvantages of the linear cascade control algorithm were analysed.Thirdly,the relationship between the current loop and position loop control parameters and the system performance was discussed .Finally,the nonlinear cascade control algorithm of the joint-structure in high-speed maglev train was introduced. In the algorithm,the current loop controller gain would be reduced when the positional deviation increases. At the same time, the gain of the position loop controller would be increased. The simulation results show that the suspension joint-structure gap changes caused by the failure of a single suspension point or disturbing force ,of systems with nonlinear cascade control algorithm were less than that of systems with linear cascade control algorithm. The new algorithm can improve the anti-disturbance ability of the maglev train,It can also ensure the safety and comfort of passengers.

As the only drinking water source of Tianjin, Yuqiao reservoir had experienced several algae blooms in recent years, which had adversely impacted on the safety of drinking water supply and reservoir management. In this article, the relationship between phytoplankton biomass and related environmental variables has been evaluated in inter-annual and seasonal scale using factor analysis and liner regression method base on the monthly monitoring data covering the period of 2004-2009. The results indicate that water temperature and total phosphorus (TP) played governing roles in phytoplankton biomass in most seasons (i.e. temperature in winter and summer; TP in autumn); COD (chemical oxygen demand) presented significant positive relationships with phytoplankton biomass in autumn and BOD (biological oxygen demand) shows opposite trend with it. However, a complex interplay was found between phytoplankton biomass and nitrogen considering significant positive relationships occurring between them in spring and autumn. The results indicate that interactions between phytoplankton biomass and related environmental variables are highly sensitive to seasonal periodicity, which improves understanding of different roles of biotic and abiotic variables upon phytoplankton variability, and hence, advances management methods for eutrophic lakes.

The mechanism of horizontal subsurface-flow constructed wetland (HSSF CW) and its design guidelines were introduced for the design of a constructed wetland. A numerical model Subwet was proposed to aid the design of constructed wetland. The design of a horizontal subsurface-flow wetland was simulated by utilizing Subwet model. The treatment efficiency for a year round operation was obtained from the modelling. The factors which have effects on treatment efficiencies were analyzed and investigated in this study. The recommendations on optimizing and improving the HSSF CW design were provided. This case study of Subwet model demonstrated the applicability of this model in the design of constructed wetland. It can provide theoretical basis for the design of constructed wetland.

Due to the practical shortcomings of the classical deterministic pollution assessment model, the theory of trapezoidal fuzzy numbers was introduced to the environmental assessment system. A fuzzy risk assessment model was built based on the geoaccumulation index and biotoxicity coefficients of heavy metals. Using the fuzzy pollution risk assessment model, the risk of heavy metal pollution was evaluated for the surface sediment of Dongting Lake. The results showed that the pollution risk in a descending order was HgCdPbCuCrZnAs, with Hg,Cd and Pb being the priority pollutants in Dongting Lake. Both the intervals of possible values for the geoaccumulation indexes of heavy metals and their credible levels were calculated using this model. Compared with the results of the deterministic assessment model, the fuzzy pollution risk assessment model gave a better characetriztaion of the actual pollution status and spatial distribution difference of the heavy metals in the sediment of the studied region which is more objective and comprehensive.

Micellar-enhanced ultrafiltration was used to remove Cu2+ (Cu2+ was fixed at 0.6 mmol/L) from simulant aqueous solutions with SDS and SDBS as anionic surfactants respectively. Compare SDS and SDBS separation through permeate flux, permeate concentration, rejection and enrichment ratio. Experimental results show that the average permeate flux with SDS is always higher than that with SDBS [the average flux with SDS is 29.92 L x (m2 x h)(-1), while that with SDBS is only 16.55 L x (m2 x h)(-1)], the permeate concentration of SDS is always lower than that with SDBS. When the permeate concentration of Cu2+ close to zero, 2 mmol/L and 6 mmol/L of SDBS and SDS are respectively required. Cu2+ rejection and enrichment ratio with SDS are always higher than those with SDBS (the average Cu2+ rejection and enrichment ratio with SDS are respectively 85.06% and 4.18, while those with SDBS are 69.05% and 4.05 respectively). Besides, the average enrichment ratio of SDS is also higher than that of SDBS (SDS is up to 3.89, while SDBS is 3.13). Therefore, SDS is more suitable than the SDBS for removal of Cu2+.

A field experiment was conducted to study the effects of different tillage system (no-tillage, rotary tillage, and plow tillage) and mulching (straw mulch, sod mulch, and film mulch) on the orchard soil moisture content and temperature in Loess Plateau. Under different tillage system, the soil moisture content in 0-1 m layer differed significantly in May, with the sequence of no-tillage (14.28%)rotary tillage (14.13%)plow tillage (13.57%), but had less difference in September. Straw mulch induced significantly higher soil moisture content than sod mulch, film mulch, and no-mulch. Among the treatments tillage plus mulching, no-tillage plus straw mulch resulted in the greatest soil water storage. The average soil temperature at daytime was in order of film mulchno-mulchsod mulchstraw mulch, and the change range of soil temperature was no-mulchfilm mulchsod mulchstraw mulch. Soil water storage under different mulching treatments was not always negatively correlated with soil temperature, but depended on the water conservation effect and heat-preserved capacity of mulching material. Above all, the main conservation tillage system for the orchards in Loess Plateau would be no tillage plus straw mulch.

Micellar enhanced ultrafiltration (MEUF) is a new method which is based on the surfactant of the unique characteristic of parental molecular structure that can remove heavy metals in the water. The concentrated solution by dealing with the MEUF contains high concentration of heavy metal ions, so it must be need for further processing. The electrolysis method was employed to recovery Cd2+ from the concentrated solution of micellar enhanced ultrafiltration (MEUF). Effects of type of electrode, electrolysis voltage (U) and time (t), solution pH, surfactant to Cd2+ molar ratio ([SDS]/[Cd2+]) on Cd2+ recovery efficiency were investigated. The study found that the surfactant had some effect of resistance to electrolysis process. The optimum experimental conditions were obtained: stainless steel (anode)-graphite (cathode), U = 2.8 V, t = 100 min, pH = 4, [SDS]/[Cd2+] = 5 ([SDS] = 8.5 mmol/L constant). And the recovery efficiency of Cd2+ in the concentrated solution was 50.26%.

The retentate stream containing Cd2+ was chosen for the investigation. Effects of acid reagent, chelator, pH and operation mode on separation of Cd2+ and recovery of SDS, as well as efficiency of reclaimed SDS were investigated. The optimum conditions in acidification were obtained: H2SO4 as acid reagent, pH = 1.0, operation mode of batch. Under these conditions, separation of Cd2+ and recovery of SDS are 98.0% and 58.1%, respectively. And the efficiency of reclaimed SDS for removing Cd2+ is 80.2%. In chelation, the optimum conditions were investigated: EDTA as chelator, uncontrolled pH (pH = 4.4) and operation mode of batch. Under these conditions, separation of Cd2+ and recovery of SDS are 90.1% and 60.5%, respectively. And the efficiency of reclaimed SDS for removing Cd2+ is 79.4%.

A nitrophenols-degrading bacterium, strain NS12, was isolated from a mangrove sediment by enrichment culture under aerobic conditions. Based on the analysis of 16S rDNA gene sequence the isolate was identified as Achromobacter xylosoxidans Strain NS12 was able to metabolize both o-nitrophenol (ONP) and p-nitrophenol (PNP) as the sole source of carbon, energy and nitrogen. However, this strain was not able to use 3-nitrophenol (MNP) as the only source of carbon energy and nitrogen for growth. The study demonstrated that when PNP and ONP occurred as a mixed substrate PNP degradation restrained the degradation of ONP and caused the major carbon source shift from ONP to PNP. Moreover, the results showed nitrophenols could be degraded by the indigenous bacteria in mangrove sediment.

Between 1993 and 2003, the proportion of urban residents without health insurance rose from 27 to 50%. The probability of outpatient visits in the previous 2 weeks dropped from 19.9 to 11.8% in urban areas between 1993 and 2003, and from 16.0 to 13.9% in rural areas. To improve risk-pooling and risk-sharing, private health insurance should play an important role in China's health insurance system. This paper estimates the demand for private health insurance in urban areas using contingent valuation methods. Individuals were asked about their willingness-to-pay (WTP) for major catastrophic disease insurance (MCDI), inpatient expenses insurance (IEI), and outpatient expenses insurance (OEI). The study was based on a household survey conducted in four small cities in China in 2004 and included 2671 respondents. More people would like to buy IEI and MCDI (48.5 and 43.0%, respectively) than OEI (24.5%). In addition, individuals would pay a higher premium for MCDI and IEI than for OEI. The price elasticities of demand for MCDI, IEI, and OEI were -0.27, -0.34, and -0.42, respectively. The determinants of enrollment in the three private health insurance programs were similar with employment status, age, education, and income.

With continuing stringent environmental regulation, the traditional techniques are incapable of reducing the concentration of dissolved organics and heavy metals to the levels required by law or prohibitively expensive. Surfactant-based separation process such as micellar-enhanced ultrafiltration has been extensively proposed. Micellar-enhanced ultrafiltration has been demonstrated to be effective in removal of heavy metals and/or organic contaminants from wastewater stream. The process can be low energy cost and easily included in a whole process. Micellar-enhanced ultrafiltration has been shown to be a promising method for the removal of low-levelsof heavy metal ions and organic compounds from industrial effluents. This paper introduces the working mechanism, main factors of MEUF and the selection of surfactant and membrane. The lasted study progress on the application of micellar-enhanced ultrafiltration is reviewed. The recovery and reuse of surfactant from the retentate and permeate are also discussed.

The five-coordinate copper(II) complex [(3,3′-trimethylenedinitrilo)bis(2-butanone oximato)]copper(II) bromide (CuHLBr) has been prepared and its crystal structure has been determined. The complex has a square-pyramidal structure with the copper displaced 0.43 A out of the basal nitrogen plane. The CuBr distance is 2.955 A. The differences in the structures of the copper(II) and copper(I) complexes is discussed. Covalency of the coordinate bond for the title complex is also discussed based on ESR spectra.