Quantification of the effects of management factors on maize (Zea mays L.) and cotton(Gossypium hirsutum L.) residues decomposition rate

Efforts to quantify management effects on decomposition rate of added substrates to the soil is important especially where such information is to be used for prediction in mathematical or simulation models. Using data from a short term (60 days) greenhouse simulation study, a procedure for quantifying effects of management on SOM and substrate decomposition is presented. Using microbial growth rate u (q), microbial efficiency in substrate utilization e (q), specific decomposition rates for added plant residues to two contrasting soils, red earth (Ferrasol) and black earth (Acrisol) were estimated. The treatments included straw addition + buried, (T1); straw addition + mineral N (T2); and straw addition + tillage, (T3). Sampling was done every 15 days. Straw decomposition rate was affected by external mineral N sources (Urea 46% N). Addition of an external N source significantly increased decomposition rates. The study could not, however, fully account for the effect of tillage on residues because of the limited effect of the tillage method due to the artificial barrier to mechanical interference supplied by the mesh bags. It is concluded that using few decomposer parameters, decomposition rates and consequently SOM trends in a soil system can be monitored and quantification of the influence of perturbations on decomposition rate of added substrates possible.

Human Health Risk Assessment Model of Organic Pollution in Groundwater:Shijiazhuang Industrial Zone

In this study, a risk-based management model is developed and applied to an industrial zone. The models proposed by the United States Environmental Protection Agency and Han Bing have been improved by adding a residual ratio of volatile organic compounds （VOC） after boiling and deleting the related parameters in half-life. Using this improved model, an integrated process was used to assess human health risk level in the study area. Compared with water quality analysis, the results highlight the importance of applying an integrated approach for decision making on risk levels and water protection. The results of this study demonstrated that： （1） Compared with these permissible level standards in China （GB 3838-2002） and National Primary Drinking Water Regulations of the United States, the residents＇ daily life had not been affected by the groundwater in this area （except for relative bad water quality of HB3-4 and HB3-6）; （2） The typical detected organic contaminants of all groundwater samples were chloroform, carbon tetrachloride, trichloroethylene and tetrachloroethene, and the pollution sources were mainly industrial sources by preliminary investigations; （3） As for groundwater, the non-carcinogenic risk values of all samples do not exceed the permissible level of 1.0 and the carcinogenic risk values are relatively lower than the permissible level of 1.00E-06 to 1.00E-04; （4） Drinking water pathway of trichloroethylene and tetrachloroethylene mainly contribute to increasing the health risk of residents＇ in study areas; （5） In terms of non-carcinogenic risk and carcinogenic risk, the health risk order for drinking water pathway and dermal contact pathway was： drinking water pathway 〉 dermal contact pathway.

Reaction Process of Heavy Hydrocarbons Hydrogenation in Ebullated Bed

The properties and structural changes of unconverted oil(UCO)obtained from ebullated bed hydrogenation at different residue conversion rates were analyzed to clarify the reaction process of heavy components.Meanwhile,the processing routes of UCO,delayed coking,and solvent deasphalting,were investigated.The results showed that with the increase of conversion,the impurity removal rate increased;meanwhile the contents of sulfur and metal in UCO decreased,while the contents of nitrogen and residual carbon increased,and the colloidal stability of UCO became worse.The structural parameters of UCO indicated that the change in molecular structure of heavy oil mainly covered the opening of cycloalkanes ring,hydrogenation saturation of aromatic rings and dealkylation reaction during hydrogenation in the ebullated bed;the aromatic structure was basically unchanged at high conversion,and was mainly due to the ring opening of cycloalkanes and the fracture reaction of alkyl side chains.The coking route of UCO showed that low sulfur petroleum coke with different grades could be prepared by adjusting the conversion in ebullated bed to produce UCOs with different properties.The coke generating coefficient and sulfur transfer coefficient in UCO coking process were higher than those in residue coking.The properties of deasphalted oil(DAO)of UCO were significantly improved and could be used as FCC or hydrocracking feedstock.The DAO yield of UCO feedstock at high conversion was higher,and its sulfur content was lower and CCR value was higher.

Liquefaction and FTIR analysis of two desert shrubs Salix psammophila and Caragana intermedia

In order to extend the investigation of the characteristics of desert shrub liquefaction and the structure of liquefied desert shrubs, we studied the liquefaction of Salixpsammophila and Caragana intermedia in the presence of phenol and used FTIR analysis on unliquefied and liquefied S. psammophila and C. intermedia. The results showed that the liquefaction effects are enhanced with an increase in temperature, catalyst content and liquid ratio. FTIR analysis proved that more active functional groups appeared after S. psammophila and C. intermedia were liquefied in the presence of phenol. These results can provide a theoretical basis for the further utilization of liquefied S. psammophila and C. intermedia and the development of desert shrubs in a new utilization field.

Comparison of Skidding Performance of Small Track-type Experimental Prototype Skidder and J-50 Skidding Tractor

In this paper, field experimental comparison is made between a small track-type experimental prototype skidder and a J-50 skidding tractor. Experimental data, including skidding productivity, soil compaction on skidding trails, and damage rate of the residual trees, are analyzed. The results indicate that with the condition of scattered skidding area and low skidding volume per cycle, small track-type experimental prototype skidder has advantage on working and a higher skidding productivity. It makes lower soil compaction to the skidding trails in the depth of 0-5 cm, 5-10 cm, and 10-15 cm. Under the same work conditions, the damage rate of the residual trees made by small track-type experimental prototype skidder is only 1/5 of those made by J-50 type skidding tractor. The damage rate is reduced by 80%.

Experiment and optimal design of a collection device for a residual plastic film baler

It is imperative to carry out research on residual plastic film collection technology to solve the serious problem of farmland pollution.The residual plastic film baler was designed as a package for film strip collection,cleaning and baling.The collection device is a core component of the baler.Response surface analysis was used in this study to optimize the structure and working parameters for improving the collection efficiency of residual film and the impurity of film package.The results show that the factors affecting the collection rate of residual film and the impurity of the film package are the speed ratio(k)between the trash removal roller and eccentric collection mechanism,the number(z)and the mounting angle(θ)of spring teeth in the same revolution plane.For the collection rate,the importance of the three factors are in the order,k>z>θ.Meanwhile,for the impurity,the importance of three factors are in the order,z>k>θ.When the speed ratio,the mounting angle and the number of spring teeth was set at 1.6°,45°,and 8°,respectively,the collection rate of residual film was 88.9%and the impurity of residual film package was 14.2%for the baler.

Migration regularities of impurities C,O,Fe,Co and Ni and effect of crystal transition on C,O and Fe in purification of metal La by solid-state electrotransport

Migration regularities of impurities C,O,Fe,Co and Ni and the effect of crystal transition on C,O and Fe in purification of metal La by solid-state electrotransport(SSE)were studied.The impurity migration direction,removal extent and difficulty were intuitively judged by impurity residual rate distribution curve.It is indicated that major impurities Fe,Co,Ni,C and O in metal La are found to significantly migrate to anode and migration effects are much better with the increase in temperature and prolongation of time in purification of La by SSE.Impurities Fe,Co and Ni in La may be fast diffusion elements,which are very extreme to be removed,and removal difficulty is in the order of Fe<Co<Ni<O<C.When La was migrated for 100 h at 800℃by SSE,the residual rates of impurity Fe,Co,Ni,O and C are 0.25%,10.10%,40.04%,64.00%and 70.04%,respectively.The crystal transition of La,transformed from fcc crystal to bcc crystal,has significant effect on migration of interstitial impurities,and removal effect of interstitial impurities C and O can be significantly improved when purification was performed above crystal transition temperature of 865℃of La.However,there is little effect on Fe.When La was migrated at 880℃for 100 h,residual rates of impurities C and O are,respectively,19.90%and 32.67%lower than those at 820℃for 100 h,while that of Fe is lower than0.25%in both situations.Therefore,more pure metal La can be obtained through further increasing temperature,especially above crystal transition temperature of 865℃of La.

Migration regularities of impurity aluminum and copper in purification of metal lanthanum by solid-state electrotransport

In view of the previous studies on the migrations of impurity aluminum(Al)and copper(Cu)in purification of rare earth metal by solid-state electrotransport(SSE),there are still some questions about that which direction they migrate to and whether there are significant migrations or not.The metal lanthanum(La)was used as research object,and the effects of migration temperature and time on the distributions and migration regularities of impurity Al and Cu were investigated in the present study by increasing concentration of impurity Al and Cu in raw metal La.The impurity migration direction and removal difficulty were intuitively judged by the residual rate distribution curve of impurity.It is indicated that metal impurity Al and Cu in metal La at 800℃ with direct current are found to significantly migrate to anode and their residual rates near cathode decrease with the increase in migration temperature and prolongation of migration time.The relatively large vapor pressure of Al and Cu makes their residual rate distribution curves being low in middle and high in ends.When metal La was continuously purified for 100 h at 800℃ by SSE,the residual rates of impurity Al and Cu at 20 mm from cathode are 68.43%and 57.43%,respectively,showing that Cu is much easier to be removed than Al.