The parameters of elemental chlorine-free (ECF) bleaching (D0EpD1) of eucalyptus kraft pulp were optimized to reduce AOX formation. The optimal conditions were pulp concentration 10%, ClO2 dosage 2.8%, pH 3.5, temperature 60°C, time 60 min at D0; H2O2 dosage 1.25%, alkali dosage 2.0%, temperature 65°C, time 105 min at Ep; ClO2 dosage 0.2%, pH 4.5, temperature 60°C, time 55 min at D1. AOX formation was 0.553 kg.tp–1, each stage was 0.470 kg.tp–1, 0.060 kg.tp–1 and 0.023 kg.tp–1, respectively. Compared with un-optimized AOX formation decreased by 23.7%.The brightness and viscosity was 84.36% ISO, 834.6 mL.g–1. In fact, good quality of the pulp was obtained when AOX formation has fallen dramatically. These provide a theoretical basis for reducing the produce of AOX and realizing the clean bleaching.
Hospital wastewater (HWW) is a source of estrogenic activity compounds in the environmental water system. Once released into water bodies, these compounds disrupt the aquatic ecological balance and even affect human health. On the basis of domestic and foreign literature, the potential chemicals and their properties, such as construction features and toxicological effects, in HWW were summarized and discussed. The advantages of ozone in removing target substances were also summarized.
Cable transmission has its intrinsic advantages and it is the development tendency of intelligent drilling among all kinds of signal transmission. According to the structure characteristics of the intelligent drill string, this paper analyzes the transmission line distribution parameters of intelligent drill string combined with average transmission theory; transfer matrixes of single drill pipe, drill pipe joint and that of cascaded transmission line between them are all calculated by the transmission line transfer function; impedance model of intelligent drill string communication channel model are built according to that transfer matrix based on the two-port network, then this model is simulated by experiment and the result is analyzed; curve of error rate is got and the influence of different signal-noise ratio, different transmission rate and different transmission distance on signal transmission performance are analyzed. This model simplifies the calculation, and the frequency characteristics and attenuation characteristics of transmission line are obtained under the analog signal and the digital signal, then the average transmission signal characteristics of intelligent drill string is analyzed by intuitive squiggle. Maybe this paper could provide some theoretical guidance for intelligent drill string.
As a ternary compound, CuInS2 with band gap about 1.5 eV, has chalcopyrite crystal structure, high absorption coefficient and low toxicity of sulfur, therefore, CuInS2 is a promising absorbing layer used in solar cells with thin films. Electroplating method has many advantages of low cost and easy operation etc. CuInS2 precursor samples were prepared by electroplating with raw materials of CuCl2·2H2O, InCl3 and Na2S2O3·5H2O etc., and the precursor films were heat treated in sulfur atmosphere. The phases of product samples were determined by X-ray diffraction (XRD) and the surface morphology was observed by scanning electron microscopy (SEM), and the elemental content of the film was analyzed by energy dispersive spectroscopy (EDS). Results show that uniform and dense CuInS2 precursor films can be obtained under conditions of CuCl2·2H2O, InCl3, Na2S2O3·5H2O and C6H5Na3O7·2H2O with contents of 10 mmol/L, 10 mmol/L, 100 mmol/L and 1.25 mmol/L respectively, pH 3.5 and deposition potential –1.0 V. CuInS2 film with good crystallinity was obtained by sulfurizing precursor film at 350 oC for 6h, has different XRD peaks for (112), (024/220) and (116/132) crystal planes respectively. Many lumps with uniform size are found, and there are little holes distributing on the surface after heat treatment. The precursor and sulfurized films were all found containing copper, indium and sulfur elements. It is found that the sulfur content in the films was obviously increased after sulfurizing.
The cable transmission line has more obvious advantages in long-distance information transmission, and is suitable for the transmission of various MWD signals during drilling. The research on the information transmission pattern of the cable transmission line will be the focus of intelligent drill string. According to the characters of the intelligent drill string, combing with the nonuniform transmission line theory, and considering the effect of temperature variation on the impedance of the smart drill string, the distribution parameters of the cable transmission line has been analyzed. On the basis of the two port network system, the transfer function and the transport matrix of the nonuniform transmission line have been obtained, and the model of nonuniform transmission line impedance of the intelligent drill string cable has been established. In order to verify the feasibility of the established model, the communication channel model has been built utilizing the MATLAB/Simulink software. Through experiment simulation and result analysis, the error rate curves under different parameters have been obtained, the transmission rate and transmission distance of different signals have been explored, and the influence of modulation and demodulation on data transmission quality has been studied, which provides a certain reference for the information transmission pattern of the intelligent drill string.
City water demand forecasting is of great significance in reducing the cost of electricity consumption and municipal planning. Back-propagation (BP) neural network has been widely adopted in water demand forecasting in recent years. But BP performs unsatisfactorily in terms of training time and global searching ability, so in this paper we improve BP by two heuristic algorithms, namely, genetic algorithm (GA) and particle swarm optimization (PSO), respectively. The testing and verification of the three algorithms (BP, GA+BP, PSO+BP) have been conducted on real-life water demand forecasting of Beijing city. The obtained results demonstrate that, in spite of the execution time consumed, both GA+BP and PSO+BP performed with higher accuracy and less errors than BP. The obtained results also illustrate that PSO+BP slightly outperformed GA+BP in terms of forecasting accuracy.
This paper aims to investigate the influence of curing condition on compressive strength of low-calcium fly ash-based geopolymer concrete (FAGC) by preparing six mixtures. The results also show that the specimens cured at room temperature for one day and then cured at high temperature will be helpful to obtain materials with higher strength than that of directly cured specimens at high temperature. Additionally, cured at room temperature for one day and then cured at high temperature would weaken the adverse effect of wet curing on the growth of compressive strength.
This paper presents the results of experimental investigations on steel tube strengthened recycled concrete (STSRC) exposed to high temperatures and reinforced by CFRP. The failure mode, bearing capacity and deformability of the columns were investigated to analyze the effects of CFRP, temperatures (300°C, 500°C and 700°C), and recycled coarse aggregate (RCA) replacement ratios (0%, 50% and 100%) on mechanical performance. The results indicate that the higher exposed temperatures, the more cracks occurred and the lower ultimate load carrying capacities for the specimens, and the failure mode and load capacity could be increased greatly by external strengthened with CFRP sheets. However, the higher RCA replacement ratio could induced a smaller cracks and higher load capacity, and the specimens with 50% RCA ratio gave the highest load capacity when exposed to high temperature. In addition, the ABAQUS software was employed to conduct finite element analysis (FEA) of STSRC reinforced, and a comparison of results calculated using the proposed model exhibits good agreement with an experimental results.
Given the rapidly increasing popularity of online impulse buying using digital platforms, it has raised significant interests about the antecedents of consumer behaviour. The aim of this study is to compare the main factors which influence online customers’ purchase decisions on clothing in PRC and the UK. The study conducted was exploratory in nature, aiming to create an understanding of impulse purchasing behaviour before, under and after the actual action. The results show that several factors such as price discounts, online comments, can strongly affect the impulse buying behaviour among online customers. This study provides novel insights for marketing literature and online retailers. The result of this research would contribute to retailers and marketers who wish to penetrate the market in the UK and China who is already present in the market and wishes to keep the loyalty of their consumers. It can also be a part of the research on international customer behaviour towards online apparel shopping.
Accompanied with rapid economic growth and human development, the world faces severe water shortages, which pose a serious threat to human society. In the present study, the significance of water environmental quality evaluation and problems found in available evaluation methods were discussed, with a focus on prior research results. This paper selected ammonia nitrogen (NH3-N), chemical oxygen demand (COD), cyanide, volatile phenol and petroleum as evaluation factors, and established level-evaluating and order-arranging models of water environmental quality on the basis of information entropy and uncertainty measure theory. The uncertainty influence factors based on the real situation were quantitatively and qualitatively analyzed, and the experimental data were used to establish the uncertainty measure function. Also, we adopted information entropy theory to calculate the weight of the index, and determined the level and level order of water environmental quality based on credible degree recognition criterion. The developed model was applied to assess water environmental quality in four sections of Dan River Basin. The results show that uncertainty measure method is reasonable, with the potential significance of assessing water environment quality in the future.
Resource recovery of municipal solid waste (MSW) incinerator fly ash is widely concerned. Tobermorite, an important but rare naturally mineral, could not be directly hydrothermal synthesized from it owing to its high content of Ca but low concentration of Si and Al. The selected external silicon-aluminum additives including coal fly ash (CFA), bentonite, kaolin and diatomite were solely or combined added. With the addition of 30% mass composite additive in which the ratio of quality for CFA and diatomite is 1:1, tobermorite could be synthesized most effectively in 48h at 150°C, mainly attributing to the proper element proportion adjusted by additives. Tobermorite seed added could not only promote the large formation of tobermorite, but also inhibit the production of hibschite and kaotoite. Since Ca/(Si + Al) = 1.20 and Al/(Si + Al) = 0.20, addition of 30% mass of composite additive and 3% mass of tobermorite seed would be the recommended technological parameter.
According to the data about annual average air pollution and the main crop yield between 1997 and 2013 in Wuhan City, we studied the impact of crop production on the air quality in Wuhan City. The results showed grains production’s increase will increase annual average nitrogen dioxide in the air. Increase of oil production will reduce annual average nitrogen dioxide in the air. In addition, increases of emissions of industrial dust and soot will raise the annual average particulate matter in the air. Increase of emissions of industrial nitrogen oxides will augment the annual average nitrogen dioxide in the air.
In order to effectively reduce the compression wave in tunnel and the micro pressure wave at the exit of tunnel, improve the comfort of passengers, this study put forward laying polymeric sand porous material in tunnel by using the sound absorption properties of porous media, and give the numerical simulation calculation method of the aerodynamic effect of three-dimensional compressible, viscous and unsteady flow field when a high-speed train entering into a tunnel, furthermore, the influence of sound absorption board on the aerodynamic effect in tunnel was studied. Theoretical analysis and numerical results show the compression wave in tunnel and the micro pressure wave at the exit of tunnel can be decreased significantly when pasting porous materials in tunnel. The reason is mainly due to there are lots of micro-pores in the material and it could absorb the energy from compression wave, then the peak value of it and pressure gradient are decreased. Secondly, the method of laying polymeric sand sound absorption material has influence on the change of the pressure in the tunnel and the micro pressure wave at the exit of tunnel. When the length and height of sound absorption materials are same, calculation results show that the best pressure reduction effect is achieved when laying the material at the entrance of tunnel. However, when laying the material at different circumferential positions of tunnel, the pressure reduction effect at haunch is better than vault and spandrel. Based on that, considering the pressure noise reduction problem, material cost and height of construction in practical engineering, when laying the material at haunch, the relationship between the reduction effect of pressure gradient and the length of laying is summarized with 3 different speeds, which have certain reference value for the design of the method of laying sound absorption material in tunnel.
Land resources and land use activities support the social and economic development in any region. In order to explore the distribution of land use structure, we can apply the Lorenz curves and Gini coefficient to accomplish. In this study, we selected the land use data in 14 prefecture cities in Liaoning Province of China from 2010 to 2015. Based on the Lorenz curve and the Gini coefficient, we analyzed quantitatively the land use structure in 14 prefecture cities of Liaoning province. Results indicated that cultivated land, forest land and construction land were evenly distributed, while garden land, grass land and unused land were distributed in a more concentrated state in space scale. On time scale, the Gini coefficient of forest land, garden land and grass land were increasing, and the degree of distribution dispersion has increased, while the Gini coefficient of cultivated land, construction land and unused land has reduced, whose distribution tended to equilibrium. Some suggestion for rational land use and structural adjustment has been provided by analyzing the spatial and temporal distribution of land use in Liaoning Province.
A new compound, O-ethyl formate phenylacetic acid, was synthesized by one-pot method with homophthalic acid, CH3OH and Ca(ClO4)2·2H2O. The new compound was determined by elemental analysis and single crystal X-Ray diffraction analysis. The o-ethyl formate phenylacetic acid crystallize in monoclinic, space group C2/c with a = 20.908(4) A, b = 5.2154(10) A, c = 20.045(4) A, β = 97.21(3)o, V = 2168.5(7) A3, Z = 1, Dc = 1.104 μg·m–3, μ = 0.064 mm–1, F(000) = 720, and final R1 = 0.1967, wR2 = 0.4907. The title molecules form 1D chained structure by the interaction of intermolecular hydrogen bonds and π-π stacking.
The open pit locating in Cangshang was closed in 2005 because the reusing of pumping water resulted in the cyclic change of slope water level. In order to study the influence of water level fluctuation on mechanics parameters of the slope rocks, two kinds of typical rocks are selected to have the uniaxial compression tests of different saturation-dehydration circulation. The damage evolution law of rock mechanics parameters under water-rock interaction is found, whose results show that the mechanical properties of rock are weakened obviously by the water-rock interaction. In addition, the stronger the water-rock interaction becomes, the more obvious the weakening phenomenon is. Due to the different sensitivity to various parameters of water-rock interaction, the extent of elastic modulus decrease is the largest and uniaxial anti-compressive strength takes the second place while Poisson's ratio is essentially constant. Moreover, the uniaxial compressive strength and modulus of elasticity present exponential distribution with times of saturation-dehydration circulation. With the increase of the saturationdehydration times, the damage value increases accordingly while the increment tends to zero. Generally, the rock mechanical properties are hardly affected by water-rock interaction in the latter period; there are differences among the damage degree of various qualities of rocks, the better the quality, the smaller the damage, and the less the times reaching 95% limit damage value.
The accelerating urbanization and improvement of living standards have greatly increased the municipal solid waste (MSW) generation in China. Public private partnership (PPP) widely used in the field of waste-to-energy (WTE) industry can decrease the volume of MSW, generate power and address the serious environmental problems caused by MSW. The advantage of PPP model can be expressed in its inherent incentive, expanding product quality, improving capacity utilization, saving transaction costs, improving efficiency of WTE industry. We collect data of municipal solid waste disposal fee from 69 PPP WTE projects of 231 operating projects, covering 30% of all PPP WTE operating projects in 29 provinces from 1999–2016, the spatial-temporal model is built to analyze the waste-to-energy environmental efficiency in PPP waste-toenergy industry.
The expressway crack identification is significantly important for the expressway safety maintenance, and the crack detection is one of key technologies for the crack identification. This paper proposed an expressway crack detection method based on improved Pulse-Coupled Neural Network (PCNN), used minimum cross-entropy algorithm to obtain the optimal iterations of PCNN algorithm, and then complete the segmentation of expressway images by combining the simplified PCNN algorithm. The results showed that this method could inhibit the background noise and better extract continuous crack edge to provide good characteristics for crack identification in the next step.
