The present paper takes as its target for study the medium sand and the typical pollution factor NH+4-N,aiming to discover their effects on the quality of polluted river water as well as the nearby groundwater,particularly on the water quality of the northwest arid and semi-arid areas. For the sake of research success,we have conducted a series of indoor soil column experiments to simulate the process of how the pollutants permeate and act on the water,trying to analyze the effects of the thickness of vadose zone and the concentration of pollutant factors in the water body on the adsorption of NH+4-N. While doing the above experiments,we have been paying particular attention to the study of the mechanism of adsorption of NH+4-N by the sandy soil. As is well known,the mutual interactive relation between river water and the groundwater in the northwest arid and semi-arid areas plays a crucial role in guaranteeing the water quality and the drinking water safety from the local groundwater resource. The results of our experiments show that (1) The adsorption isotherm curve of NH+4-N reveals that on the Langmuir adsorption isotherm curve,the biggest adsorption capacity is 56.5 mg/100 g soil; (2)Adsorption of NH+4-N through the same media,the dynamic adsorptive capacity turns to be far smaller than the static adsorptive one,and the mass concentration of NH+4 proves bigger,with the two differential values being greater; (3) The thickness of the media has hardly any effect on the adsorptive capacity of NH+4 at the same mass concentration; (4) For the same vadose zone,the adsorptive capacity,as well as the equilibrium concentration,the adsorption rate tends to increases with the increase of the mass concentration of NH+4 in injection,but the time of adsorption equilibrium tends to be invariable with the declining consumption of the liquid volume when the balance is achieved.
This paper is aimed to report its authors' breakthrough renovation over the conventional early warning model of airport accidents by using the BP network system in its process.In our research,first of all,we have defined more clearly the characteristic features of BP network and pointed out the out-of-date operational routine still prevailing in the current Chinese airports,thus,laying a successful foundation to its application.In doing so,we have also explained why it is necessary to choose the two levels of the BP network for its practical application.Next,we have ascertained the index system of the early safety warning practice with the simulation data concerned being done by SPSS principal components analytic method.Furthermore,the training and test of this BP model has been checked by using the MATLAB software.Test results of our research prove that our model is feasible and efficient for its mission.For practical purpose,we have also presented the structure,the function,as well as the principles of our renovated early warning system in a detailed way,which is highly applicable on the basis of bi-level constitutional model.
By using a complex(optional) reaction detector,the paper has done a series of on-spot testing over the reaction characteristics of the professional drivers while they were driving on the Talimakan Desert Roads,including their reaction time and number of missing reactions,in hoping to find the features of their reaction characteristics in the special desert condition.To be exact,what we have done in this study is to find the likely particular characteristics of the drivers' driving performance on the desert roads,such as the reaction time and number of missing reactions,so as to determine the main driving influential factors,such as the their age difference,their driving experience,driving duration,and the desert temperature changes,on the their driving performance,and then to find if there exist any inherent correlations of such characteristics with their desert driving based on our analysis of the 1 004 random sampling results.The results of our on-spot testing and analysis indicate that,under the influence of the impatient mentality on the desert roads,they prefer to drive faster than on the regular roads with the greater number of spontaneous missing reactions.The average reaction time and the number of missing reactions are 0.74 s and 2.71 s,respectively,which belong to Level B national standard.On the other hand,the grey incidence analysis also indicates that there likely exists significant relationship between the reaction time and the number of missing reaction with the influential factors,including the drivers' age,years of driving, the lasting driving time for the particular case,as well as the particular desert air temperature pre-and post-the driving testing.Compared with other factors,it is shown that the drivers' reaction time is more significantly affected by the air temperature,with the influence of the number of miss reactions followed by their continuously lasting driving time.Thus,it can be concluded that the reaction characteristics of the drivers are more affected by the long-lasting driving fatigue.
This paper has investigated five methods for modifying activated carbon as well as the different adsorption properties of aniline and Cr(Ⅵ) among all the modified activated carbons.The results of our investigation prove that the best adsorption capability for aniline and Cr(Ⅵ) can be achieved by using the carbons modified by HNO3.The removal ratios of carbon 1 # and 2 # to aniline can increase by 13.19% and 11.34% in comparison with that of the original,at the same time,the removal ratio of Cr(Ⅵ) may increase by 47.32% and 44.28%,respectively.At the same time,better effect can also be achieved by means of direct microwave radiation,that is,with N2 modified activated carbon (carbon 3 #) but with no effect on Cr(Ⅵ).This process can be checked through Boehm test,which may indicate that the HNO3 oxidation on the acid surface of the activated carbon is likely to result in the enhancement of the acid surface functional groups,which in turn helps to enhance the adsorption capacity of Cr(Ⅵ).And,consequently,the microwave radiation would change the pore structure of the activated carbon.Thus,it can be concluded that different modification methods can be applied to activated carbons according to different pollutants so as to achieve the best removal efficiency.
This paper aims to present our ideas on how to apply the atmospheric environment carrying capacity (AECC) to the planning environmental impact assessment(PEIA) . As is known, with the fast development of our industry and urbanization, it has become an urgent need to PEIA so as to improve our living and production conditions. Actually, PEIA has become an indispensable method that can help to adjust the regional development and air quality control so as to save energy and reduce the pollutant emission. This paper hopes to focus its attention on the analysis of the methods and application procedure of AECC in PEIA, by way of analyzing the characteristics and the impact factors of the AECC so as to establish analysis indicators and corresponding methods for the AECC analysis. In doing our research, we take Nansha area of Guangzhou as our case study. According to the state planning, some giant projects will be built in Nansha, including a petrochemical plant and a steel-making factory at the south part of Nansha, about 50 kilometers away from Hong Kong SAR, in addition to other large industrial projects now in intensive planning driven by the Nansha Regional Development Program and the local center of the Pearl River Delta. Seeing the strong implication of the planning to the depressing air quality of the region, we think it an imperative need to apply the environment impact assessment approach to the Nansha Area development planning.
The present paper is to introduce our testing results on the spontaneous combustion of high sulfur-contained mining ore. In order to test and control the spontaneous combustion of sulfide mining ore and improve the quality of the mine environment, we have chosen four kinds of chemical reagents (coded A, B, C, D) in hope to find the efficient sulfide ore spontaneous inhibitor from the compounds mixed in different proportions in our experiments. Then, the compounds as candidate inhibitors were added to the copper ore samples chosen from the Dongguashan Mine at the normal temperature, respectively. To make the experimental results accurately reflect the actual situation on the field, we have been to Dongguashan mine three times to collect sulfur iron ore samples, which had been sealed up for preservation in dry granularity. According to the demands for choosing sulfur inhibitors and the features of iron ore, we have decided to do the experiments in laboratory conditions. All the samples were then measured from time to time (3-5 d) with a precision balance with accuracy of 0.1 mg with the weight changes recorded. The test time tends to last about 65 d. The experimental data were to be carefully dealt with to find the changing curve of the rate resistance with the purpose to determine the effective, practical formula for the quality change of the inhibitors. The results of our experimental studies have shown that the water glass with sulfuric acid plays quite a good role of the resistance on the spontaneous combustion of high sulfurcontained minerals.
There has been increasing concern about the widespread occurrence of endocrine disrupting chemicals (EDCs) in the water environment, for example, bisphenol A (BPA), a typical EDC, which is widely used in industries. Currently, the degradation of ED- Cs such as BPA by advanced oxidation process has become a research focus. Potassium ferrate (K_2FeO4), an efficient, non-toxic and multipurpose water treatment agent, has the effect of oxidation, disinfection, adsorption and coagulation etc. In this paper, the excellent oxidation potential of K_2FeO4 was used to degrade aqueous BPA employing jar tests. The purpose is to provide theoretical basis for the application of BPA degradation by K_2FeO4. The BPA degradation efficiency under different conditions was investigated. The influences of tertbutyl alcohol (a free-radical inhibitor) and background constituents in natural water, such as humic acid (a natural organic matter), Si32-, and HCO3~-, were analyzed. The results showed that BPA was readily degraded by K_2FeO4 oxidation and the suitable oxidation time was 30 min. The pH significantly influenced the stability and oxidability of K_2FeO4, and the optimal pH for BPA degradation was 5.0 - 6.0. The BPA degradation rate increased with increasing K_2FeO4 dosage and decreasing initial BPA concentration. With an initial BPA concentration of 2 mg/L and a K_2FeO4/BPA molar ratio of 3, BPA was almost completely removed. The background constituents in natural water showed different influences on BPA degradation. The existence of humic acid, SiO32- and tert-butyl alcohol in water decreased the BPA degradation rate, while the existence of HCO3~- improved the BPA degradation. The natural organic matter of 12 mg/L decreased the BPA degradation rate by 16%. The HCO3~- concentration of 50 mg/L increased the BPA degradation rate by 5 % . Both SiO32- and tert-butyl alcohol slightly inhibited the BPA degradation.
The present paper is inclined to review the recent advances in treating nitrogen-containing pollutants for the aquatic environment by taking the blue algae bloom of Taihu Lake for example. As is known, industrial sewage, household sewage and fish farming sewage are the three major sources of nitrogen-containing sewage. In this paper, two kinds of treating technology. are mainly discussed, especially the new biological nitrogen removal technology, including simultaneous nitrification and denitrification, short-term nitrification-denitrification, anaerobic ammonium oxidation and deammonification. In addition, the physical-chemical process, the biological denitrification process and the integration process have been introduced with a brief mentioning of the treating processes of typical nitrogen-containing wastewater, such as ammonia nitrogen, organic nitrogen, nitrate wastewater and landfill leachate. Besides, a primary prospect for the development tendency of economic, efficient and steady techniques has also been made. Thus, it can be seen that the biological treatment technology will be made more popular in pollution control and reduction of the pollution coming from nitrogen-containing contaminants.
The paper is aimed to introduce its discussion over the problem of the urban water security by taking Lanzhou as a case study sample. As is known, Lanzhou is a city lying on the famous Yellow River basin in North-West of China and known for its water-short situation. In such a situation, it is of extreme importance to make an indepth study over the water resource situation of the city and the surrounding areas so as to heighten the water resource exploration and exploitation efficiency. It is just from this need that we have developed an improved PSR model by selecting all the likely factors that may influence water-use security. When the assessment indicator system is established, all the assessment indicators to be used in the water security system are determined by the AHP method with 33 indicators and 5 grades chosen to describe the water security situation. Then we have worked out a set of composite indexes of water security assessment and all the factors affecting the successful assessments from the practical assessment experiences gained in the period between 2000 to 2007. The model proposed by this paper can provide better theoretical guidance for the economic development and inter-regional water security coordination. At the same time, it can also provide a common ground for exploration of more comprehensive advanced ideas for urban water security assessment systems. The results of the application of our model indicate that the water security state in situ in Lanzhou has been improved since 2000, but the pressure, state and public response are different. All in all, human economical activities have been playing a key role in the final analysis. In addition, the paper suggests that Lanzhou should strengthen its flood-controlling system while seeking the optimal utilization of the polluted water and developing water-recycled use system for water-saving and clean production. Another proposal here we would like to make is that the city should establish a more effective response mechanism to the Yellow River water changing situation so as to increase the greening rate of its south and north mountains with more investment onto the hydraulic engineering projects, the water resource bearing capacity and ensure the city water-supply-and-use security.
Fault tree analysis (FTA) was applied in present paper to find out the major factors, which took heavily impacts on qualities of the γ-Al 2O 3 coatings. And eighteen preparation parameters were resulted from the analysis, as the major events for controlling the coatings qualities. Structure-weight of the eighteen factors was also calculated in detail in the paper. Then the importance of the eighteen events was discussed systematically based on large amount of experiments. It was concluded that sintering temperature and time as well as pore-forming additives and their content are major parameters for quality control of γ-Al 2O 3 coatings. In the end, fault tree analysis is believed naturally to be used to analyze the factors affecting the qualities of γ-Al 2O 3 coatings. And this analysis technology can provide certain useful theoretical guidance for the preparation of γ-Al 2O 3 coatings.