In this paper, the effect of POA PPD together with resin-stabilized asphaltenes on the flow behavior of model waxy oils was investigated through rheological test, DSC, microscopic observation and asphaltenes precipitation test. Compared to the POA or asphaltenes alone, POA/asphaltenes cannot further decrease the wax appearance temperature of oils, but can dramatically decrease the pour point, gelation point, G′, G″ and apparent viscosity of oils. POA molecules can adsorb on the surface of asphaltenes, thus inhibiting the asphaltenes precipitation and forming the POA/asphaltenes composite particles. The composite particles can act as wax crystallization templates and then greatly change the wax crystals' morphology into large and spherical-like, thus improving the waxy oil flow behavior.
The tillage experiment trials were established in Dehui County,Jilin Province in 2001.The effects of no-tillage(NT) and moldboard plow(MP) with the crop of corn on the content of soil organic carbon(SOC),total nitrogen(TN),available nitrogen(N),phosphorus(P) and potassium(K) in plow layer of black soil in Northeast China were studied.The results showed that the significant differences in SOC and TN occurred at depths between NT and MP.NT tended to stratify SOC and TN in the plow layer.Aavailable N,available P and available K had remarkable differences between soil surface and subsurface.In conclusion,NT resulted in the obvious accumulation of SOC,TN,available N,P and K on soil surface.
Effects of livestock wastewater treatment on the chlorophyll and antioxidant enzyme systems in leaves of Phragmites australis were investigated by simulating the natural condition under two concentrations of livestock wastewater: high concentration of raw livestock wastewater and mid-concentration of livestock wastewater which was diluted to half from the raw livestock wastewater. High concentration livestock wastewater had stronger effect on Phragmites australis than mid-concentration livestock wastewater. Under the stress of livestock wastewater, the content of chlorophyll decreased, the ratio of chlorophyll a/b increased, the activities of catalase (CAT) decreased, the activities of peroxidase (POD) decreased obviously at the first three days and then reached almost the same activities at the end of the treatment when compared with the control, while the activities of superoxide dismutase (SOD) increased but fluctuated during the treatment. The results indicated that Phragmites australis had very strong anti-adversity abilities and tolerances to livestock wastewater, and could enormously relieve the contradiction between the development of livestock breeding and environment contamination if it was used in the treatment of livestock breeding wastewater.
In this paper, the enhanced adsorption of methylene blue (MB) dye ion on the activated carbon (AC) modified by three surfactants in aqueous solution was researched. Anionic surfactants—sodium lauryl sulfate (SLS) and sodium dodecyl sulfonate (SDS)—and cationic surfactant—hexadecyl trimethyl ammonium bromide (CTAB)—were used for the modification of AC. This work showed that the adsorption performance of cationic dye by activated carbon modified by anionic surfactants (SLS) was significantly improved, whereas the adsorption performance of cationic dye by activated carbon modified by cationic surfactant (CTAB) was reduced. In addition, the effects of initial MB concentration, AC dosage, pH, reaction time, temperature, real water samples, and additive salts on the adsorption were studied. When Na+, K+, Ca2+, NH4+, and Mg2+ were present in the MB dye solution, the effect of these cations was negligible on the adsorption (<5%). The presence of NO2- improved the adsorption performance significantly, whereas the removal rate of MB was reduced in the presence of competitive cation (Fe2+). It was found that the isotherm data had a good correlation with the Langmuir isotherm through analyzing the experimental data by various models. The dynamics of adsorption were better described by the pseudo-second-order model and the adsorption process was endothermic and spontaneous. The results showed that AC modified by anionic surfactant was effective for the adsorption of MB dye in both modeling water and real water.
The reduction adsorption of silver diamminonitrate on different kinds of activated carbon fibers (ACF) has been studied in this paper. The effect of different parameters, including adsorption temperature, concentrations of activation agents, and activation time on the silver adsorption capacities of activated carbon fibers has been investigated. The results show that higher temperature in which the silver complex interacts with ACF, or higher concentration of activation agent, will make higher reduction adsorption capacities of ACFs. More over, ACFs activated with phosphoric acid have higher reduction capacities than those activated with zinc chloride or steam.
Since 1999, the "Grain for Green" Program has been extensively implemented in the Loess Plateau region. This measure has largely been of concern not only for its contribution to soil erosion reduction but also for its effects on carbon sequestration. The aim of this study was to assess the carbon sequestration characteristics of different restored vegetation types in areas with severe soil erosion on the Loess Plateau and to compare the effects of restoration age and slope direction on the vegetation carbon sequestration. To evaluate the carbon density and composition characteristics of different ecosystem types, six typical vegetation types (including farmland, grassland, Hippophae rhamnoides Linn., Caragana korshinskii Kom., Robinia pseudoacacia L., and Populus davidiana Dode.) were selected in the Loess Hilly Region, i.e., Wuqi County and Zhidan County in Northern Shaanxi province, which is a typical area for the implementation of artificial vegetation restoration. The results showed that:① vegetation restoration in the semi-arid loess region had a profound impact on carbon sequestration. The carbon density of different vegetations, as well as different vegetation components including above-ground vegetation, below-ground roots, and litter, shared the same pattern as tree>scrub>grassland>farmland. The 0-40 cm soil layer of the farmland showed the lowest soil organic carbon density (1355.5 g·m-2), compared to which those of grassland, H. rhamnoides Linn., C. korshinskii Kom., R. pseudoacacia L., and P. davidiana Dode. were higher by 91.4%, 125.2%, 144.0%, 124.5%, and 232.6%, respectively. ② It was common in grassland, H. rhamnoides Linn., C. korshinskii Kom., and P. davidiana Dode. for the carbon density of different vegetation components as well as soil organic carbon density of different soil layers (0-5, 5-20, and 20-40 cm) to generally show an increasing trend with increased restoration age. ③ Slope direction had a significant impact on the vegetation carbon density only for H. rhamnoides Linn., C. korshinskii Kom., R. pseudoacacia L., and P. davidiana Dode., while showing the contrary for farmland and grassland. Soil organic carbon densities for sunny slopes were significantly lower than those for shaded slopes by 22.9%, 34.3%, 75.8%, 49.1%, 22.4%, and 69.4%, respectively, for farmland, grassland, H. rhamnoides Linn., C. korshinskii Kom., R. pseudoacacia L., and P. davidiana Dode. ④ Ecosystem carbon density varied significantly for different ecosystem types, among which farmland showed the lowest (2022.1 g·m-2), and grassland, H. rhamnoides Linn., C. korshinskii Kom., R. pseudoacacia L., and P. davidiana Dode. showed values higher by 48.7%, 152.8%, 125.1%, 166.3%, and 530.7%, respectively. The carbon density of each ecosystem component showed a pattern as follows:soil layer>above-ground vegetation layer>root layer>litter layer. Soil organic carbon constituted the main part of the ecosystem carbon density and accounted for 67.0%, 86.3%, 59.7%, 72.7%, and 56.5%, respectively, for farmland, grassland, H. rhamnoides Linn., C. korshinskii Kom., and R. pseudoacacia L. These results can provide an essential basis for scientific management of ecosystem carbon pools and promote ecological environment management on the Loess Plateau.
Purpose – Inkjet printing is becoming increasingly important and popular for the printing of textiles. As one of the environmentally friendly processes, the plasma has been widely used to modify the surface properties of inkjet printing substrates. The purpose of this paper is to investigate the nano-modification of plasma on polyester fabric for pigment inkjet printing. The actual printing performance and the related mechanical behavior of samples were also evaluated. Design/methodology/approach – Polyester fabrics were surface modified by atmospheric pressure air plasma with the aim to improve its inkjet printing performance. The effects of plasma treatment on surface properties of fabrics were characterized using X-ray photoelectron spectroscopy (XPS) and Scanning electron microscopy (SEM). The wettability of the samples is evaluated by measurement of contact angles of different polar liquids and surface energy. Breaking strength and elongation, bending rigidity are tested to evaluate the mechanical behavior of treated and control fabrics. Findings – It was found that the nano-modification of plasma markedly improved the anti-bleeding property of inkjet printing fabrics. SEM and XPS analyses indicated that this improved color performance was mainly contributed by not only the etching effect and oxygen containing polar groups induced onto fiber surfaces. In addition, the results of mechanical behavior test indicate no evident reduction of breaking strength and breaking elongation both in warp and weft direction after plasma modification. Originality/value – The surface modification method used here offers an economic and dependable way for pretreatment of inkjet printing fabrics with the advantages of environmental friendly over traditional pretreatment methods.
To evaluate the influence of 3 different restorations on the fracture resistance of endodontically treated premolars with minor loss of dental defect in order to direct clinical design.Seventy-two recently extracted intact and single-rooted human mandibular premolars for orthodontic reason were collected and randomly divided into 3 groups (group A, B, C, n=24). Each group was respectively prepared into 1/3 defect of occlusal surface (group A), 1/2 defect of occlusal surface (group B) and 1/3 defect of proximal-occlusal surface model (group C). Then each group was divided into 3 subgroups with one restored with a light-curing composite resin(group A1, B1, C1), one restored with cast metal full crowns following a light-curing composite resin (group A2, B2, C2), and one restored with fiber posts and resin cores and cast full crowns after teeth preparations (group A3, B3, C3, n=8). Static loading tests were performed on each specimen until cracked.Fracture strength was tested and fracture patterns were examined. The data was analyzed using SPSS17.0 software package.The fracture resistance of subgroup A2 was different when compared with subgroup A1 and subgroup A3. In group B and C, the fracture resistance of teeth in subgroup B2, B3, C2 and C3 were significantly higher than that in subgroup B1 and C1. There was no significant difference in the fracture mode of 3 restorations in group A, B and C.A composite resin combined with cast metal full crowns can be used as the first choice to restore endodontically treated premolars with proximal-occlusal 1/3 defects and occlusal defects that do not surpass 1/2 dimension of occlusion.
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