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Abstract: Grey theory is one approach that can be used to construct a model with limited samples to provide better forecasting advantage for short-term problems. Generally, the GM (1,1) and Discrete GM (1,1) models are two typical grey forecasting models in grey theory. However, there are two shortcomings in the above grey models respectively, i.e., the homogeneous-exponent simulative deviation in GM (1,1) model, and the unequal conversion between the original and white equations in DGM (1,1) model. In this paper, we firstly propose a novel Generalized GM (1,1) model termed GGM (1,1) model, based on GM (1,1) and DGM (1,1) models, to overcome the above shortcomings. Then, we detailedly study four important properties in this new grey model. Four estimative approaches of stepwise ratio in GGM (1,1) model context is also covered. In the end, we simulate and forecast the fuel production in China during the period 2003–2010 using three GM (1,1) models. The empirical results show that GGM (1,1) model has higher simulative and predictive accuracy than GM (1,1) and DGM (1,1) models. This work contributes significantly to improve grey forecasting theory and proposes a optimized GM (1,1) model. [Copyright &y& Elsevier]

Abstract: This paper presents an analytical framework to estimate the Total Allowable Area for Coastal Reclamation (TAACR) to provide scientific support for the implementation of a coastal reclamation restriction mechanism. The logic of the framework is to maximize the net benefits of coastal reclamation subject to a set of constraints. Various benefits and costs, including the ecological and environmental costs of coastal reclamation, are systematically quantified in the framework. Model simulations are developed using data from Tongan Bay of Xiamen. The results suggest that the TAACR in Tongan Bay is 5.67 km2, and the area of the Bay should be maintained at least at 87.52 km2. [Copyright &y& Elsevier]

Abstract: The effective modeling of the urban landscape dynamics in a megalopolitan cluster area (MCA) is essential to understanding its spatial evolution process. However, existing urban landscape dynamic models based on cellular automata (CA) are limited in that they do not consider urban flows (e.g., flows of people, material, and information) between the different cities/towns in an MCA. This paper proposes a new megalopolitan landscape dynamic model (MLDM) that is better suited for simulating the urban landscapes in an MCA by combining a gravitational field model (GFM) with a CA model. The GFM was used to model the influence of inter-city urban flows and to refine the transition rules of the CA model. The MLDM was applied to simulate the urban landscape in the MCA of Beijing–Tianjin–Tangshan, and produced more accurate simulation results than the CA model that did not account for urban flows. The MLDM-based prediction of future landscapes suggested that urbanization will continue in the region through 2020, especially in a few ‘hotspot’ areas. Close attention should be paid to these areas for strategic regional planning and environmental protection in this heartland of China. [Copyright &y& Elsevier]

Abstract: Double curved arch bridges have played an important role in the history of bridge construction in China. The strengthening or retrofitting of this type of bridge has attracted a great deal of research attention in the Chinese bridge engineering community. In this paper, a novel strengthening method, i.e. the extrados section augmentation strengthening method (ESASM), has been reported. Firstly, the rationale behind this new method and the changes in internal forces after strengthening have been studied in details. A numerical optimization analysis was then performed to derive a strengthening design solution based on these results. Secondly, a trial use of this novel strengthening method in a double curved arch bridge has been reported. A numerical simulation was carried out to analyze the internal forces in the bridge both before and after it was strengthened. Results show that internal forces have been favourably redistributed after the bridge has been strengthened by using ESASM. Lastly, the adopted construction method and the strengthening effect for that project were described. [Copyright &y& Elsevier]

Abstract: Research on earthquake-induced collapse simulation has a great practical significance for super-tall buildings. Although mega-braced frame-core tube buildings are one of the common high-rise structural systems in high seismic intensity regions, the failure mode and collapse mechanism of such a building under earthquake events are rarely studied. This paper thus aims to investigate the collapse behavior of a super-tall mega-braced frame-core tube building (H =550m) to be built in China in the high risk seismic zone with the maximum spectral acceleration of 0.9g (g represents the gravity acceleration). A finite element (FE) model of this building is constructed based on the fiber-beam and multi-layer shell models. The dynamic characteristics of the building are analyzed and the earthquake-induced collapse simulation is performed. Finally, the failure mode and mechanism of earthquake-induced collapse are discussed in some detail. This study will serve as a reference for the collapse-resistance design of super-tall buildings of similar type. [Copyright &y& Elsevier]

Abstract: Solving China's severe energy problems relies on the efficient implementation of energy-related policies at the provincial level. On the context of 12th Five-Year Plan, most provinces’ energy developments are faced with the double pressures, that is, the rapid economy development and energy conservation. Thus, it is necessary to explore the scenarios of energy, economic and social development on the provincial level, especially in western developing provinces. This paper proposes a framework of economy and energy system including three major components: economy growth, population and energy intensity, to identify the regional energy balance and CO2 emission by 2015. With an application to Qinghai Province, policies related to energy development can be classified into three subcategories: economic and social development, energy development, and energy saving policies. Then, five scenarios are set and simulated to explore the energy balance and CO2 emission under the constraints of economic growth and energy intensity. Results show that in Qinghai, energy demands will increase by 90.37% in 2015 with a significant adjustment in industrial structure; and the implementation of the energy saving policies in Qinghai province is necessary. Besides, increasing production of clean energy can significantly reduce the consumption of fossil fuels and the environmental impact. [Copyright &y& Elsevier]

Abstract: This paper presents the pre-experiment plan and prediction of the first stage of vacuum laser acceleration (VLA) collaborating by UCLA, Fudan University and ATF-BNL. This first stage experiment is a proof-of-principle to support our previously posted novel VLA theory. Simulations show that based on ATF''s current experimental conditions the electron beam with initial energy of 15MeV can get net energy gain from an intense CO2 laser beam. The difference in electron beam energy spread is observable by the ATF beam line diagnostics system. Further, this energy spread expansion effect increases along with an increase in laser intensity. The proposal has been approved by the ATF committee and the experiment will be our next project. [Copyright &y& Elsevier]

Abstract: This paper develops an overall methodology for investigating the thermal and power behaviors of semi-transparent single-glazed photovoltaic window for office buildings in Hong Kong. In order to estimate its overall energy performance, this study is conducted in terms of total heat gain, output power and daylight illuminance. Three simulation models are established, including one-dimensional transient heat transfer model, power generation model and indoor daylight illuminance model. A typical office room reference is chosen as case study, and the weather data from 2003 to 2007 from the Hong Kong Observatory are used as the simulation inputs. By incorporating the simulation results, the overall energy performance can be evaluated in terms of electricity benefits corresponding to five orientations of the studied typical office. The priority of office orientation considering overall energy performance is: south-east, south, east, south-west and west. The findings show that thermal performance is the primary consideration of energy saving in the entire system whereas electricity consumption of artificial lighting is the secondary one. The overall annual electricity benefits are about 900 kWh and 1300 kWh for water-cooled and air-cooled air-conditioning systems respectively. The application of semi-transparent PV glazed window can not only produce clean energy, but also reduce building energy use by reducing the cooling load and electrical lighting requirements, which definitely benefits our environmental and economic aspects. [Copyright &y& Elsevier]

Abstract: Student dormitories are both living and resting areas for students in their spare time. There are many small rooms in the dormitories. And the students are distributed densely in the dormitories. High occupant density is the main characteristic of student dormitories. Once there is an accident, such as fire or earthquake, the losses will be cruel. Computer evacuation models developed overseas are commonly applied in working out safety management schemes. The average minimum widths of corridor and exit are the two key parameters affecting the evacuation for the dormitory. The effect of varying these two parameters will be studied in this paper by taking a dormitory in our university as an example. Evacuation performance is predicted with the software FDS + Evac. The default values in the software are used and adjusted through a field survey. The effect of varying either of the two parameters is discussed. It is found that the simulated results agree well with the experimental results. From our study it seems that the evacuation time is not in proportion to the evacuation distance. And we also named a phenomenon of “the closer is not the faster”. For the building researched in this article, a corridor width of 3 m is the most appropriate. And the suitable exit width of the dormitory for evacuation is about 2.5 to 3 m. The number of people has great influence on the walking speed of people. The purpose of this study is to optimize the building, and to make the building in favor of personnel evacuation. Then the damage could be minimized. [Copyright &y& Elsevier]

Abstract: In subtropical Hong Kong, buildings consume the most of the electricity use. Computer simulation technique is a useful tool for predicting building thermal and energy performance. Simulation computer programs require weather data input to drive the mathematical models within the simulation tools for comparative studies and annual energy estimation. Typical weather year data representing the long-term climatic conditions are often used. Recently, there has been an increasing interest in incorporating daylight in the architectural and building designs to reduce building energy consumption. However, daylight parameters are not always available. In 2003, the International Commission on Illumination (CIE) adopted a range of 15 standard skies covering probably the whole spectrum of the usual skies in the world. Once the skies have been identified, the basic solar irradiance and daylight illuminance at various inclined planes can be obtained. This paper presents the work on the development and evaluation of two typical weather datasets, namely Typical Meteorological Year (TMY) and Test Reference Year (TRY). Measured hourly weather data for the 30-year period from 1979 to 2008 were analysed. Building energy simulations were conducted to evaluate the two weather datasets. Daylight parameters were derived using luminous efficacy approach and the sky conditions were categorized based on common climatic variables. [Copyright &y& Elsevier]

Abstract: Closed unlined landfills can found in many cities in China, as a side product of economic and urban development in last century. The degradation velocity of municipal solid waste (MSW) in such landfills can be very slow due to lack of moisture and its stabilization time can reach twenty years or more if no measure is enforced from outside. Recently aerobic bioreactor landfill technology has been applied to accelerate MSW decomposition by introducing water and air into the landfill. However, excessive water could also result in secondary pollution to ground water. In order to apply the aerobic bioreactor landfill technology for unlined landfills treatment without leachate across the site boundary, an appropriate water injection volume has to be determined. In this paper, a 3D mathematical model is established from mass balance and Darcy''s law in a cylindrical coordinate system for the simulation of moisture distribution in an unlined aerobic bioreactor landfill. Moisture profile in landfills is obtained by coupling the aerobic bio-reaction with the water generation term at different scales. The aerobic bio-reaction rate is considered as the function of moisture content, temperature, matrix concentration, oxygen concentration and microorganism concentration. Two water injection styles, surface ponding and vertical well, were investigated. To avoid ground water contamination, moisture filtration rate is assumed to be zero at the site bottom. A feasible water injection volume is determined under quasi-steady- state. [Copyright &y& Elsevier]

Abstract: Based on the statistical methods of corpus and the 124 love-songs of Tshang yang Gya tsho as the studying object, this paper have set up the principles of vocabulary segmentation and built the love-songs corpus of Tibetan and Tibetan-Chinese grammar separation lexicon corpus. Then it did quantitative research on the achievement of “love-songs” in the language arts from three aspects: the length of the vocabularie''s, the frequency rate of the vocabularies, and the distribution of the term''s number in the verses and the songs. In addition it also introduced a new kind of researching idea and method for the study of Tibetan literature. [Copyright &y& Elsevier]

Abstract: The development of China''s animation should take some excellent artistic forms of our nation into consideration, only those animation works with national characteristics are precious. The designer should comprehend the essence of traditional cultures, combine the traditional artistic elements on modeling and can recreate. This paper creates animation images with Chinese culture characteristics through analyzing the Chu art characteristics and taking them as artistic reference of animation modeling. Its application in the FLASH software and some noticeable problems are considered; and the animation modeling has unique artistic charms and values. [Copyright &y& Elsevier]

Abstract: A novel method for dynamic risk assessment of oil spill accidents based on numerical simulation was presented in this paper. The dynamic risk assessment model was developed consisting of a comprehensive list of caused consequences like environmental damage, asset loss, health impact and social effect as well as emergency actions preventing these losses. Contributing events in the Mater Logic Diagram (MLD) of the dynamic risk assessment model were valued based on the simulated evolvement of oil contaminants under spill scenario on quasi-static fluid, which was obtained by coupling an oil spill model with hydrodynamic module in Jialing river of Three Gorges Reservoir in China after the impoundment of the reservoir to 175m water level in 2010. Calculated result of dynamic risk as grade IV indicated that the assessed oil spill was not as catastrophic as we thought because of the slow transport of oil fractions on water surface and absence of dispersed oil in water body due to the quasi-static fluid, very gentle wind and effective emergency actions, as well as by the reason that rare agriculture or industrial crops exist in spill adjacent area. [Copyright &y& Elsevier]

Abstract: High energy gas fracturing (HEGF) technique has been one of central stimulating measures to enhance oil recovery in low permeability reservoirs. But, in recently few years, some serious CO poisoning accidents took place in oilfields here in China. It is very important to reveal the dynamic mechanisms of carbon monoxide flow and diffusion to operating safety during high energy gas fracturing. In this paper, some dynamic mechanisms of carbon monoxide CO flowing inside a oil wellbore and diffusion on the top of the well during high energy gas fracturing were studied with fluid/gas hydrodynamics. The CO flow model within a wellbore and the diffusion model in air were established. The key factors affecting CO flow and diffusion such as wellbore pressure, gas–oil ratio, wind speed, leakage speed, air-permanence were inspected with mathematical simulation. It will be of significance to provide an important guidance for monitoring and preventing CO poisoning accidents during high energy gas fracturing. [Copyright &y& Elsevier]

Abstract: For the caving and sliding control of roadways with large cross-section, thick mudstone roof and abutment pressure influence, the cable truss system is proposed and its support mechanism is thoroughly analyzed in this paper. Furthermore, according to the geometric size and ground pressure conditions on field coal roadways Nos. 101, 102 and 103 in Xinyuan Coal Mine, three types of cable truss support systems are designed for obtaining the optimum cable truss support system. Then the corresponding parameters for each support design are determined by use of the numerical simulation method, and three kinds of support systems are put into practice. The field observation results show that roof should be effectively controlled by the normal cable truss structure consisting of two long cables and one connector, and both coal sides can be protected by the simplified cable truss structure composed of two short cables and one channel bar. Finally, the optimal support system is gotten which is much better than the other two support designs in rock deformation control effect and economic profits. [Copyright &y& Elsevier]

Abstract: This paper investigates the efficiency and equity of morning peak ramp control schemes in a freeway corridor with limited capacity. In terms of efficiency, both short-run and long-run optimal ramp control schemes are obtained by minimizing the total travel cost and maximizing the total social benefit along the corridor. It is found that for a short-run optimum with inelastic demand, the morning peak period is of the same duration for different on-ramp locations. But for a long-run optimum with elastic demand, the peak duration for various on-ramps increases with the local capacity elasticity of demand. In terms of equity, two measures are defined from a demand-based viewpoint and a space-based viewpoint. It is shown that the short-run optimal ramp control scheme is perfectly fair from a demand-based equity viewpoint. Consequently, two typical ramp control schemes—a perfect demand-based equity scheme and a perfect space-based equity scheme—are introduced and compared with the long-run optimal ramp control scheme in terms of efficiency and equity. Numerical simulations using survey data from China suggest that the perfect demand-based equity scheme attains an economic welfare level that is very close to the optimal one and the conflict between efficiency and equity diminishes as demand becomes less elastic. [Copyright &y& Elsevier]

Abstract: We abstract bus transport networks (BTNs) to complex networks using the Space P approach. First, we select three actual BTNs in three major cities in China, namely, Beijing, Shanghai and Hangzhou. Using the SIS model, we simulate and study the epidemic spreading in the three BTNs. We obtain the density of infected vertices varying with time and the stationary density of infected vertices varying with infection rate. Second, we simulate and study the epidemic spreading in a recently introduced BTN evolution model, the network properties of which correspond well with those of actual BTNs. Third, we use mean-field theory to analyze the epidemic dynamics behavior of the BTN evolution model and obtain the theoretical epidemic threshold of this model. The theoretical value agrees well with the simulation results. Based on the work in this paper, we provide the following possible forecasts for epidemic dynamics in actual BTNs. An actual BTN should have a finite positive epidemic threshold. If the effective infection rate is above this threshold, the epidemic spread in the network and the density of infected vertices finally stabilizes in a balanced state. Below this threshold, the number of infected vertices decays exponentially fast and the epidemic cannot spread on a large scale. [Copyright &y& Elsevier]

Abstract: The engineering background of this paper is the upper protecting seams exploitation of Huangsha Mine, By use of CFD software to analyze the methane delivery law in U type ventilation work face gob. By analyzing the density distribution, pressure distribution, velocity field and mash methane concentration of air-methane mixed gas, obtained the locations of gas drainage hole, and summed up the methane delivery law in U type ventilation work face gob. [Copyright &y& Elsevier]

Abstract: In recent years a large number of floods occurred in the Dongting Lake region, China, and flood prevention and control have become a focus in the middle Yangtze River. How to use the dispersed sub-fast-flood storage area in Dongting basin rationally and control water level and flow process will improve flood prevention ability. In this paper an improved systematic flood simulation method coupling one and two-dimensional hydraulic model is established aiming at special area. The flood evolution process, different flood discharge scale, flood storage and embanking effect are simulated according to the changing spatial gate position and extra flood magnanimity for the typical hydrologic years. An optimized scheduling scheme by using the parallel algorithm and numerical computing method is preferred in different flood periods. The research results indicate the optimized flood diversion gate and operation scheme in three shunts river system will directly control the water level in the whole lake region. The research results provide practical basis for systematic floods control and is helpful to assess flood disaster in Yangtze River basin. [Copyright &y& Elsevier]

Abstract: Hydrodynamic conditions play an important role in formation and disappearance of spring algal blooms in the Xiangxi Bay (XXB), a typical tributary water body of the Three Georges Reservoir. As it is difficult to obtain sufficient hydrodynamic information through expensive field monitoring, in this paper, a three-dimensional hydrodynamic model is developed to simulate the flow field of XXB in spring. In order to study the influence of thermal density flow on the hydrodynamics of this tributary, two typical scenarios for the spring of 2005 are considered here: with and without the temperature sources. Our modeling results show that the flow around the mouth of XXB is mainly controlled by the mainstream of the Yangtze River, and: if the temperature effect is considered, the computed maximum influence range of the Yangtze River can reach up to about 12km upstream from the mouth of XXB. However, if the temperature effect is ignored, the influence range is only about 1km. In reality, due to the vertical temperature difference, the stratified flow is formed and the mainstream flow can reach up to 12km upstream from the mouth. The modeled results show that, the flow of Yangtze River enters into XXB in the upper layer, while the water of XXB flows out through the bottom layer. A huge vertical circulation was formed in the XXB, which enhances the exchange capacity between the Yangtze River and the XXB. The field survey also found that. It is included that the water temperature must be included in hydrodynamic numerical simulation for XXB in spring. The study is a useful supplement to field survey, and can provide technical support for eutrophication control in other tributary of Three Gorges Reservoir. [Copyright &y& Elsevier]

Abstract: This paper investigates the use of pragmatic markers by college learners of English in China. It compares the use of pragmatic markers in different contexts by students at different proficiency levels. An audio-video instrument called the Video Oral Communication Instrument was conducted to elicit ratable speech samples. inventory of the most common lexical items in spoken interaction was adopted as the analytical model. Quantitative and qualitative analyses indicate that advanced students were more active and involved than intermediate students in the use of pragmatic markers, and showed a greater sensitivity to different types of simulated interactive context. The findings suggest that the proficiency level relates to the way pragmatic markers are used both generally and across contextual variations. [Copyright &y& Elsevier]

Abstract: In this paper, the 3D Finite Element Method was combined with a Discontinuous Deformation Analysis (DDA+FEM) to study the influence of the Wenchuan earthquake on the stability of the tectonic blocks system of the Qinghai–Tibet Plateau under the background of northward extrusion of the Indian Plate and obstruction of the strong crust of the Sichuan basin. With constraints from GPS data and focal mechanisms, we first calculated the velocity and stress fields of the region. Then, we numerically simulated the rupture process of the seismogenic fault of the 2008 Wenchuan earthquake in overthrust form with a right-lateral component. We then studied the movement and deformation of the tectonic blocks that was caused by the earthquake and its influence on the stress state of the boundary faults. The numerical simulation indicates that the large earthquake causes the most tectonic blocks in the study zone at approximately a 1-mm deviation toward the northeast; in particular, the Wenchuan seismogenic fault obviously deviated eastwards, and the maximum deviation reaches 1.5m. It seems that the large earthquake causes the Bayankala block at the west side of the Longmenshan fracture zone to extend farther eastward. The Wenchuan earthquake causes the Coulomb failure stresses on the boundary faults of the tectonic blocks in the study zone to change to different extents. The maximum change of the Coulomb failure stress reaches about 0.2MPa at both ends of the Wenchuan seismogenic fault, the south section of the Xianshuihe fracture zone and part of the southeast section of the Dongkunlun fracture zone in the upper crust. Additionally, the Coulomb failure stresses also increase to different extents between 0.01 and .02MPa in regions such as the southernmost end of the Xianshuihe fracture zone, part of the southeast section of the Dongkunlun fracture zone, and so on. [Copyright &y& Elsevier]

Abstract: It becomes popular to use computer simulation technique to evaluate the performance of energy utilizations in buildings. The hourly weather data as simulation input is a crucial factor for the successful energy system simulation, and obtaining an accurate set of weather data is necessary to represent the long-term typical weather conditions throughout a year. This paper introduces a stochastic approach, which is called the first order multivariate Markov chain model, to generate the annual weather data for better evaluating and sizing different energy systems. The process for generating the weather data time series from the multivariate Markov transition probability matrices is described using 15-years actual hourly weather data of Hong Kong. The ability of this new model for retaining the statistical properties of the generated weather data series is examined and compared with the current existing TMY and TRY data. The main statistical properties used for this purpose are mean value, standard deviation, maximum value, minimum value, frequency distribution probability and persistency probability of the weather data sequence. The comparison between the observed weather data and the synthetically generated ones shows that the statistical characteristics of the developed set of weather data are satisfactorily preserved and the developed set of weather data can predict and evaluate different energy systems more accurately. [Copyright &y& Elsevier]

Abstract: The three-dimensional energy resources demand-supply system is established for two regions of China, in which determination of unknown parameters is significant for the real energy resources demand-supply system. In this paper, based on Shanghai’s energy statistic data (1999–2005), the parameters of the energy resources demand-supply system can be identified by using the neural network method, and an energy resources demand-supply system reflecting the real energy resources demand-supply relationship in Shanghai is obtained. The dynamical behavior of this system is also analyzed. Theoretical analysis and numerical simulation indicate that the obtained energy resources demand-supply system has the capacity of self-regulation and demonstrates a steady state. Finally, to ensure the steady development of the energy resources demand-supply system, corresponding measures are proposed. [Copyright &y& Elsevier]

Abstract: This paper presents a system dynamics computer model to evaluate alternative type of recycling center under different policy and economy environments through comparison on the economic feasibility of recycling centers and ratio of savings to costs in C&D waste management. A case study for the City of Chongqing, China is selected. Simulated results show three key factors can contribute to the economic feasibility of recycling and the ratio of savings to costs in C&D waste management: (a) profit; (b) unit recycling cost; (c) extra revenue from location advantage (It was assumed that the mobile centers can attain extra revenue from the location advantage compared with fixed recycling centers). The sensitive analysis and comparison on ratios between public and private sector indicate that to achieve the optimum ratio of savings to costs, design of recycling centers and selection of governmental instruments are determined by the priority list: (1) low extra revenue from location advantage; (2) low profit; (3) low unit recycling cost. Meanwhile, the fluctuation of the three factors must be prior to achieve economic feasibility of corresponding recycling centers. [Copyright &y& Elsevier]

Abstract: China is a large developing country with high carbon intensity. It is likely that China will have to face the challenge of CBTA (carbon motivated border tax adjustments) in future. Meanwhile, CBTA would create price gap between CBTA users and target countries, and change the competitiveness of different producers. Under such circumstances, this paper seeks to contribute to the debate on CBTA by focusing on the potential impacts of CBTA on different regions of China from a perspective of competitiveness. We adopt two geographical divides in China (eastern–central–western zones, high-trade-openness to low-trade-openness regions), and simulate the potential impacts across regions through a general equilibrium model. Our simulation results show that CBTA would affect competitiveness of different producers, their comparative advantages, relative trade shares, outputs and emissions. CBTA would induce structure change of the economy, and result in a shift of industrial output toward non-industrial output. There are significant differences in the effects of CBTA among different regions in China. CBTA would result in a relocation of outputs across regions in China. Therefore, CBTA would also have impact on China’s regional development policy. [Copyright &y& Elsevier]

Abstract: In this paper, an improved particle swarm optimization (IPSO) algorithm is proposed. Besides the individual best position and the global best position, a nominal average position of the swarm is introduced in IPSO. The performance of IPSO is compared to different PSO variants with five well-known benchmark functions. The experimental results show that the proposed IPSO algorithm improves the searching performance on the benchmark functions. And then, IPSO, as well as other PSO variants, is applied to optimal tuning of Proportional–Integral–Derivative (PID) gains for a typical PID control system of water turbine governor. The computer simulation results of an actual hydro power plant in China show that IPSO algorithm has stable convergence characteristic and good computational ability, and it is an effective and easily implemented method for optimal tuning of PID gains of water turbine governor. [Copyright &y& Elsevier]

Abstract: Carbon capture and storage (CCS) is widely accepted as one of main solutions to mitigate global warming in the world. However, the still-high cost of CCS is one of the major concerns, in particular in developing China. In the other hand, emission control of H2S and SO2 has already become the urgent need, and the reduction target has been set in the 11th Five-Year Plan of China. Therefore, co-storage of CO2+SO2 or CO2+H2S may be an effective way to reduce CCS cost, e.g. due to saving the de-sulphur device, and enable CCS to has an earlier deployment opportunity. In this paper, we try to, at first, reveal some key problems, i.e., trapping mechanism, injectivity and leakage risk, for co-injection and co-storage of CO2 and the strong acid SO2 into subsurface spaces in a certain gas field in China. The output of this gas field includes about 6.8% H2S and 4.6% CO2. Then, we want to insight into the possibilities and potentials of co-storage of CO2+SO2 by numerical studies. After widely referring all opened and published scientifical and technical literature, we develop a model to study a porous media system associated with the thermo-hydro-chemical coupling interactions. The hydrogeology and mineralogy of the injected formation are extracted from the historical materials of the gas field. We have performed several numerical simulations with consideration of a sandstone-clay sequence under acid-gas injection conditions. The clay formation is supposed as a sealed cap rock for the co-storage disposal system. The study examines the impact of SO2 co-injection on the pH of formation brine. Co-injection of CO2 with SO2 results in a larger and more strongly acidified zone, and alteration differs substantially from that caused by the injection of CO2 alone. The mineral alteration induced by injection of CO2 with SO2 leads to corresponding changes in porosity. Significant increases in porosity occur in the acidified zones where mineral dissolution dominates. [Copyright &y& Elsevier]

Abstract: A traditional Chinese heating system, the Chinese Kang, is used by 175 million people in detached houses in the rural regions of China, especially in Northeast China. This system utilizes biomass such as corn stalks, straw, corncob and energy plants as the heat sources. The objective of this paper is to establish a set of models to simulate the energy performance of the Kang heating system in one Chinese detached house. An experimental field study was carried out to collect practical parameters in a newly constructed Chinese detached house. The dynamic performance of the Kang heating system was simulated by using IDA-ICE 4.0 embedded with an empirical model built in the field study. The results show that the simulation can obtain good overall agreement with the field measurement results. It was confirmed that the Kang model created by IDA-ICE 4.0 is capable of simulating the performance of the Kang system and of calculating energy consumption in the detached house. Moreover, the result reveals that the thermal environment in the present Chinese detached house is still poor during the severe cold season if only the Kang system is used to heat the whole house. [ABSTRACT FROM AUTHOR]

Abstract: The Sulige gas field and the Yulin gas field are located in the north of the Ordos Basin. Reservoir pressure in the Sulige area is subnormal, whereas reservoirs in the Yulin area have normal hydrostatic pressure. This paper provides an explanation of this difference. The characteristics of reservoir sediment and formation water chemistry in the gas reservoirs of these two areas were analyzed. The results showed that both reservoirs have good sealing ability. Data of numerical simulation showed that tectonic uplift resulted in a great reduction in formation pressure in the northern Ordos Basin during the late Cretaceous period, and the decrease was greater in the Yulin gas field than in the Sulige gas field. However, because the total hydrocarbon-generating intensity of the Sulige area (<24×108 m3/km2) was less than that of the Yulin area (>32×108 m3/km2), the gas supply intensity of the two areas was different. Fluid inclusion data indicate three stages of hydrocarbon charge in the 2nd member of the Shanxi formation in the Yulin area, but only two in the 8th member of the Xiashihezi formation in the Sulige area. Consequently, although the formation pressure of the Yulin area decreased significantly during the late Cretaceous period, its relatively high initial formation pressure ensured that the present pressure of the 2nd member of the Shanxi formation in the Yulin area is higher than that of the 8th member of the Xiashihezi formation in the Sulige area. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents for the first time numerical simulation of fluid flow driven by tectonic deformation related to the ore genesis in the Dachang district, South China. Our modeling results, based on a 2-D conceptual model, indicate that tectonic deformation, in particular shortening, can drive significant fluid flow in the targeted area. The mixing of the down-going surface water due to the tectonically-induced topography with the up-going deep fluid from basement due to the compressional stress occurs in the lower Dachang fault. The mixed fluids travel laterally into and become confined in the nearby Upper Devonian silicalite limestone, over which mineral deposits may form. These results are consistent with field observations. [Copyright &y& Elsevier]

Abstract: This paper presents a numerical study on the formation history of coalbed methane (CBM) reservoir in the southeast edge of Ordos Basin, China. The coal seams studied belong to the Late Palaeozoic coal-bearing series. These coal seams have a burial history and experienced the process of subsidence, rapid subsidence alternated with uplift and then uplift, sequentially, and underwent the geothermal actions at normal, extremely high, and then normal temperatures, respectively. Coal organic matter of the coal seams matured in the Triassic Period and in the Late Jurassic to Early Cretaceous Period. The results from numerical simulation reveal that CBM reservoir evolution history can be classified into five stages, namely primary, initial, stagnant, active and dissipative stages. In the first (primary) stage, coal rank was very low and there was little methane generated and stored in the coal seams. In the second (initial) stage, the coal was converted to middle-high volatile bituminous coal. As a result, a certain amount of methane was generated and began to accumulate in coal seams except part of it escaped from coal seams by diffusion and cap outburst. In the third (stagnant) stage, generation of methane was almost stagnant due to the temperature of the coal seam that dropped slightly and the maturation of coal organic matter stopped. Meanwhile CBM would keep dissipating through diffusion. In the fourth (active) stage, coal rank varied from high volatile bituminous coal A to semianthracite which accelerated pyrolysis gas formation and resulted in a large amount of methane generated at a high speed. During this period, CBM was increasingly accumulated in coal seams although there would be considerable amounts of gas dissipated from the coal seams. In the last (dissipative) stage, due to coal seams uplifted at various rates and no more methane generated, CBM was continuously dissipated by diffusion throughout the whole coal seams and by permeation at some local areas. The simulation provides insights for further interpretation of how many factors that control or affect the CBM reservoir formation history and CBM accumulation. These factors include features of coal-bearing series, characteristics of coal seams, physical properties of coal reservoir, tectonic evolution history, burial history and geothermal conditions, etc. In particular, tectonic evolution history and gas generation are critical. Under given conditions, CBM reservoirs in the study area were developed in different ways and the CBM was accumulated in the reservoirs at different levels. For example, the west part of study area is favourable for CBM accumulation. As a result, the gas content of the main coal seams in this region has a maximum of about 28 m3/t at depths of 900–1100 m, and generally increases with the increasing of burial depth from the east to the west. The coal reservoir is under-saturated in the east part where the burial depth is shallower than about 500 m while the west part is saturated. There is a close correlation of the lateral distribution of both gas content and saturation to the gas generation in the geological history. [Copyright &y& Elsevier]

Abstract: With the rapid development in economics, subway systems have been constructed in many big cities of China. Computer evacuation models developed overseas are commonly applied in working out safety management scheme. However, input evacuation parameters are not compiled from surveying passenger behavior in China. In fact, very few studies were conducted on justifying such parameters. Staircases in subway stations, particularly those connecting the platform and the ticket hall, are identified as the ‘bottleneck’ during evacuation in the subway stations. The maximum upstairs speed and the average minimum width of staircase utilized per person are the two key parameters affecting the evacuation through the staircase. Effect of varying these two parameters will be studied in this paper by taking two subway stations in China as examples. Evacuation performance is predicted with the software buildingEXODUS. The default values in the software are used and adjusted through field survey. Effect of varying either or both of the two parameters is discussed. The possible causes on the differences and the factors to affect such effect are explored. It is found that changing both parameters simultaneously would reduce the overall evacuation time by 50%. The effect of varying the two parameters on the overall evacuation performance of the whole station depends also on the occupancy density in the station; and the travel distance from the outlet of the staircase between the platform and the ticket hall to the inlet of the staircase between the ticket hall and the ground surface. [Copyright &y& Elsevier]

Abstract: Research into partnering performance measures for building and construction projects becomes crucial because a growing trend of client organizations has been observed to adopt partnering approach to procure their projects worldwide over the past decade. Although there are some related research studies and papers documented on this research area, few, if any, comprehensive and systematic research studies focus on developing a comprehensive, objective, reliable and practical performance evaluation model for partnering projects in construction. A Partnering Performance Index (PPI), which is composed of seven weighted Key Performance Indicators (KPIs), has been developed to measure, monitor, improve, and benchmark the partnering performance of construction projects in Hong Kong. A set of Quantitative Indicators (QIs) and well-defined ranges of Quantitative Requirements (QRs) for each QI have been further established using the Delphi survey technique and Fuzzy Set Theory. Evaluation of partnering success can now be based on quantitative evidences, thus tackling the subjectivity of performance evaluation. By making use of the Internet and database technology, PPI can be monitored on-line, thus saving much time, cost and efforts on data collection and retrieval than if they are done manually. As such, an Internet-based computerized partnering monitoring and benchmarking tool, namely the Computerized Partnering Performance Index System (CPPIS) has been developed. The Internet-based CPPIS enables project participants to input data at any time and location and the project administrators could perform data analysis via the Internet. The CPPIS also enables project managers to measure, monitor, improve and benchmark their partnering performances against those already stored in the database. Graphical presentations of data and various performance measures are also built in to assist various end-users to identify problematic areas and critical success factors for achieving partnering excellence. [Copyright &y& Elsevier]

Abstract: Crowding during the morning peak hours at a platform staircase in a subway station in China was studied in this paper. Passenger flow was surveyed with normal evacuation time recorded. The evacuation process was simulated with the software buildingEXODUS. Predicted results on the total evacuation time and maximum flow capacity of the selected staircase were compared with the field observations. Two parameters, the width of staircase utilized per person and the maximum upstairs walking speed used in the software were identified to be noticeably different from the field studies. Predictions agreed better with the observations after tuning these two parameters. It is concluded that the evacuation simulation software can be applied for safety design with appropriate tuning on the key parameters through field tests. [Copyright &y& Elsevier]

Daylighting has long been recognized as an important issue in architecture. In Hong Kong many buildings are constructed close to each other and hence the external environment plays a significant role in building designs. Recently, vertical daylight factor (VDF) has been used as a criterion to justify the provision of natural lighting in buildings. This paper studies the calculation approach of VDF in a heavily obstructed environment. The techniques for determining the sky component and the reflected daylight from surrounding buildings and ground surfaces are described. Calculation tools in the form of simple equations and diagrams through computer-simulation analysis were established. The performance of the proposed method was evaluated against the daylight illuminance obtained by other independent computer simulations. It was found that predictions from the proposed approach were in good agreements with those produced by simulated results. The findings provide architects and building designers with a simple method for estimating the daylight illuminance at early design and planning stage. [Copyright &y& Elsevier]

Abstract: Water footprint is an indicator showing the consumption impact on environment with water equivalent, which allows a detailed quantification of water use directly and indirectly in sectors for the domestic and abroad final consumption. This paper presents a framework of calculating national water footprint (NWF) with input–output method on China 2002. The results indicated that the NWF of China was 381m3/capyr in 2002. A new indicator termed as national water footprint intensity (NWFI) is also derived from NWF to evaluate the water consumption intensities of different sectors. Then the evaluation of virtual water trade in sectors is followed, the results of which give a detailed quantification of net virtual water import of sectors, verifying that China is a net virtual water exporter concerning the whole national sectors, which is different from the previous studies. Finally, it is suggested that the sectors with high NWFI and volume of net virtual water export should be regarded as the priority of Chinese water-saving strategy. [Copyright &y& Elsevier]

The frequent occurrence of groundwater-related damage in operational high-speed railway tunnels in China calls for swift and accurate diagnosis. Thus, this paper describes a way to detect water-bearing defects at 5–10 m using the train-borne transient electromagnetic method in operational tunnels. Due to the short detection distance, the early electromagnetic response of the receiving coil is crucial for determining the size and location of defects. First, the turn-off current in the transmitting coil is elaborated by the equivalent electronic circuit of the transmitting loop. Then the impact of changes in the relative position between the transmitting coil and the receiving coil on the early electromagnetic response are analyzed by a numerical simulation, which shows that a square transmitting coil is suitable for ultra-close detection due to the stability of the electromagnetic response at early times in the receiving coil. Finally a laboratory experiment of close-range TEM detection is carried out to clarify the necessity and feasibility of taking the early electromagnetic response of the receiving coil into consideration at this ultra-close range (5–10 m). This research provides an important theoretical basis for the development and application of train-borne transient electromagnetic method for automatic detection of tunnel defects. • The early EM characters in the transmitting coil plane are affected by loop shape. • The early EM characters in receiver coils are affected by loop relative position. • The square loop has the most stable EM response in the receiving coil at early times. • The test shows early EM response in the coil is essential for close-range detection. [ABSTRACT FROM AUTHOR]

• The mathematical model of multiple thermal inertia is established. • The multiple thermal inertia is quantified by finite element software. • An improved robust optimal model of multi-energy system is established. • Thermal inertia uncertainty affect the heat storage capacity of HN and BD. • Making full use of thermal inertia uncertainty can reduce the operating cost. The heat system has the larger inertia in the multi-energy system (MES) integrated electricity, heat and gas, and its uncertainty caused by the heating parameters variation of the practical project, which will make the scheduling and operation of the MES more difficult and complicated. In order to improve the energy efficiency and flexibility of MES, it is essential to explore the quantitative impact of thermal inertia on the regulation capacity of the MES. To tackle this problem, this paper proposes a robust coordinated optimization method for MES considering thermal inertia uncertainty (TIU). First, the multiple thermal inertia (MTI) of solid thermal storage electric boiler (STSEB), heating network (HN) and buildings (BD) are modeled, and the thermal inertia of physical models are simulated based on ANSYS finite element software. The quantitative method of the difference between the monitoring data of the heating network operation status and the thermal energy flow model is studied, and the TIU model is established. By discretizing the uncertainty domain, an improved two-stage robust optimal scheduling model for MES considering TIU is constructed. Finally, part of real MES in the Northeastern China is used in the case study. Simulation results show that the operating cost of the MES considering the uncertainty of wind power will increase by 26.9%. On this basis, the operating cost considering TIU is reduced by 16.3%. It can be seen that considering the TIU will enhance heat storage capacity of heating network and has positive benefits for MES regulation, which can balance the operating cost and robustness of the system, and promote wind power integration. [ABSTRACT FROM AUTHOR]

In the Mogao Grottoes in Dunhuang, China, temperature and relative humidity (RH) fluctuations are the main causes of the observed deterioration. In this paper, we experimentally and numerically analyze hygrothermal transfer in the cave wall of the Mogao Grottoes. A coupled heat and moisture transfer 1D model is developed to simulate the hygrothermal behavior of the cave wall of the Mogao Grottoes, which adopts the temperature and water vapor pressure as driving potentials. The model is implemented in a programming. By constructing the numerical model of the wall under boundary conditions and comparing the measured data and simulation results, we validate the numerical model and analyze the hygrothermal transfer characteristics of the wall. The temperature and moisture profiles of the cave wall are experimentally measured and numerically determined. The simulation results are compared to experimental temperature and RH values, with good agreement despite the simplifying hypotheses adopted during modeling. By analyzing the heat and moisture distributions, we find that the heat and moisture transfer process in the cave wall changes in space and time. The complicated heat and moisture transfer directions vary cyclically. Additionally, moisture transfer in the cave wall reaches the steady state more rapidly than heat transfer. Hygrothermal cycling plays an essential role in the development of mural deterioration. The developed model provides theoretical support and a scientific method for the conservation of cave sites and a quantitative analysis approach to study mural relics. • Apply multidisciplinary method to studying mural disease in historical heritage. • Set up a hygrothermal transfer model for the cave walls, and evaluate the results. • Analyze the heat and moisture transfer properties in cave walls experimentally and numerically. • Provide a salt damage mechanism on murals relating to heat and moisture. [ABSTRACT FROM AUTHOR]

The accidents caused by the instability of bedding rock slope are often encountered in the expressway construction and operation in China. The shear strength parameters of the structural plane play a major role in controlling the stability of the bedding rock slope. In this paper, in-situ direct shear tests were performed on the structural planes containing the thick muddy interlayer, which were widely distributed between the layers of muddy slate in Guizhou Expressway. A numerical model considering the thickness of the muddy interlayer and the shape of the structural plane is established using the UDEC program. Numerical analysis has been performed to reveal the shear mechanical behaviors and the progressive failure mechanism of the muddy structural plane from a mesoscopic perspective. The thickness of the muddy interlayer has a great influence on the shear mechanical behaviors of the structural planes containing the weak layer. With the increase of the thickness of the interlayer, the peak shear strength of the structural plane decreases, and the stress-displacement curve presents a strong nonlinear characteristic. Due to the uneven spatial distribution of the thickness and morphology of the muddy interlayers in actual engineering practices, it should not only adopt the results from in-situ direct shear tests, but also consider the interlayer thickness for the stability analysis of the bedding rock slope. [ABSTRACT FROM AUTHOR]

• Field experiments with various layout parameters of subsurface pipe were carried out. • Two indices H c and R d/l were proposed to represent the salt discharge effects of subsurface drainage pipes. • The relationship between H c , R d/l and subsurface pipe layout parameters were quantified. Subsurface drainage is effective for not only controlling groundwater table depth but also alleviating soil salinization especially in arid and semi-arid agricultural areas. While substantial research efforts have been spent to determine the parameters (e.g., drain depth, drain spacing, and pipe diameter) of subsurface drainage pipe layout for water drainage, less attention has been paid to determine the parameters for salt discharge, which is important in arid and semi-arid regions. This paper presents a comprehensive study that used experimental and numerical methods to determine the pipe layout parameters for both water and salt drainage. A total of nine field experiments were conducted in Yanqi County, an arid area of Xinjiang Province, China, for a combination of different values of drain depth, drain spacing, and pipe diameter. The experimental results indicate that drain depth and spacing are significantly more important than pipe diameter for soil desalinization. Soil water content and salinity measured during the experiments were used to calibrate and validate a numerical model developed for simulating soil water flow and salt transport under drainage conditions. Two proposed indices (critical depth of soil desalinization and ratio of salt discharge and leaching), combined with two existing indices (salt discharge amount and soil desalinization rate), were used to represent the soil desalinization and salt discharge effects under different subsurface pipe layout parameters. The results suggest that drain depth has a significant influence on all indices, while the drain spacing has a significant influence on salt discharge amount and ratio of salt discharge and leaching. The relationships between layout parameters of subsurface pipes and proposed indices were quantified and used to determine appropriate layout parameters of subsurface pipes. [ABSTRACT FROM AUTHOR]

Eastern margin of Ordos basin has been an active commercial coalbed methane (CBM) production area in China, where coal seams are typically characterized with thin layers, low permeability and high gas content. Hydraulically fractured vertical wells (HFVWs) are the primary means for recovery of CBM in this area, which however are usually subject to low gas production and unpromising economics. Although the multi-fractured horizontal well (MFHW) has proven as an effective solution for producing hydrocarbon resources from both tight and shale reservoirs, its applicability in efficient development of CBM reservoirs remains yet unclear. This paper presents a pilot field application of MFHW to improve CBM recovery in eastern Ordos basin. A horizontal well stimulated with 6 stages of hydraulic fractures was observed to significantly outperform HFVWs in terms of depressurization efficiency, gas production and ultimate recovery factor. Peak gas rate of the MFHW is more than five times higher than an HFVW. History matches of the MFHW and representative HFVWs were conducted to obtain key reservoir properties that are subsequently used for production predictions. Numerical simulation predicts that cumulative gas production for the MFHW is 3–15 times as that for each of the HFVWs during a production duration of 15 years. A total of 500 stochastic geological scenarios for the study area were simulated to analyze the effect of geological parameters on the superiority of an MFHW over a group of four HFVWs (which are at equivalent well construction outlays) in terms of cumulative gas production. A correlation was then developed using the alternating conditional expectation (ACE) regression method, resulting in a linear relationship between an indicator of the superiority with permeability and desorption pressure in a log-log coordinate system. This correlation can be potentially used as a criterion for fast determination of the optimal completion option in the target CBM seams. The regression results also show that the superiority of an MFHW over HFVWs is especially highlighted in thin coal seams with low permeability and low gas content. Finally, the effect of the size and spacing of stimulated area (SA) on MFHW producibility was analyzed, showing that increasing the spacing between SAs is an economically viable option when the budget for fracturing operations is limited. • Field application of MFHW was first introduced for CBM reservoirs. • Superiority of the MFHW over vertical wells was highlighted. • Effects of SA on producibility were analyzed. [ABSTRACT FROM AUTHOR]

• Numerical simulation for CN HCCB TBS helium cooling system has been completed. • Preliminarily demonstrated the operation of HCS and verifies the rationality of operational states. • The results provide foundation for further design and optimization of HCS. Understanding the thermal hydraulic behaviors of switching processes between operational states is one of key issues in the design and optimization of the helium cooling system (HCS) of China helium cooled ceramic breeder test blanket system (CN HCCB TBS). The thermal hydraulic model of HCS considering the influence of heat structural and thermal insulation layer was established, and the main switching processes for the main operational states of HCS were simulated. The results present the dynamic changes of the thermal hydraulic parameters, including temperature, pressure, helium mass, power of heater, etc. The results indicate that the operation states and relative switching processes are reasonable: the designed operational states can be achieved by controlling the heater power and circulator mass flow rate; the time consumptions for state switching processes are far less than the reserved time according to the operation campaign schedule of international thermal-nuclear fusion reactor (ITER). The work presented in this paper demonstrates the operation of HCS, which provides an important foundation for further design and optimization of the HCS. [ABSTRACT FROM AUTHOR]

Reinforcement technology for semi coal-rock roadways with large deformations is one of the most challenging areas in underground engineering support. Based on the serious deformation problem that occurred in a semi coal-rock roadway in China's Meihuajing coal mine, this paper analyzes the characteristics of discontinuity in surrounding rock structure and incompatibility in surrounding rock deformation via means of geological investigation, mechanical experiments and numerical simulation. Then, a new kind of combined supporting system with filled-wall, shotcrete, grouting cable, prestressed anchor cable and U-shaped steel support for semi coal-rock roadway reinforcement is proposed. The width of the filled-wall is determined by parameterized numerical simulation method. Field application and deformation observation shows that the proposed combined supporting system is effective to control the large deformation of semi coal-rock roadways, which can provide certain references significance for similar engineering. [ABSTRACT FROM AUTHOR]

In data centers, a large number of IT sever racks with different heat dissipation rates are arranged in multiple rows, leading to much higher per-unit heat release and therefore more uneven temperature distribution than in general buildings. This paper chooses a small-scale data center located in China to analyze the thermal environment for the operation of these critical equipments. The wind speed and temperature in the data center were measured, and a corresponding computer room model was established via computational fluid dynamics (CFD) simulation software. Based on it, the characteristics of flow field and temperature field of the data center were analyzed. The optimization methods for problem of uneven temperature distribution and chaotic air supply in the data center were proposed and verified by evaluation index. Furthermore, the return temperature index(RHI) increased from 0.918 to 0.93, the return heat index(RTI) increased from 0.222 to 0.342. • The thermal environment of a small-scale data center in Wuhan, China was measured. • The data center model was established via numerical simulation software. • The optimized schemes for the thermal environment in the data center were proposed. • Optimization of data center can provide reference for construction and operation. [ABSTRACT FROM AUTHOR]

• Shield tunnel lining damage induced by soil-water inrush is studied. • Numerical simulation matches with field results reasonably. • Strength reduction method have been applied for the consideration of soil loss. • Lessons learned from this incident have been presented. This paper reports a case study on shield tunnel lining damage induced by soil-water inrush occurred in Tianjin Metro Line 1, China through both field monitoring and numerical simulation. This incident was triggered by the non-watertight boring work of thru holes adjacent to the cross passage between the twin tunnels. Under high hydraulic gradient, the seepage-prone weak zone was formed and extended, then the outburst of soil-water slurry was occurred. Measures including plugging engineering cotton, injecting quick-setting cement and welding partition plate of steel segments, had been taken but in vain. The outburst of soil-water slurry induced soil movement around the cross passage, thus leading to the damage of tunnel lining and ground surface settlement. After sealing the water ingress holes, stabilization methods including surface grouting and inside tunnel back grouting were applied. The mechanisms of segment lining damage and the effectiveness of stabilization are investigated through both numerical simulation and field monitoring data analysis. Lessons learned from this incident have been discussed, thus providing reference for potential shield tunnelling under similar engineering conditions. [ABSTRACT FROM AUTHOR]

Large amounts of titanium-bearing blast furnace slag have been dumped in China, resulting in serious environmental contamination and a waste of precious titanium resource. At present, a process for recovering titanium from titanium-bearing blast furnace slag has been developed. Unfortunately, current size reduction techniques fail to meet the material size requirements. In this paper, a particle size controllable jet milling technology was proposed based on the idea of one-time collision between the particle and the target. To better control the breakage size, computational fluid dynamics was used to model the new jet mill giving a detailed understanding of the mechanisms. Simulated results showed that the acceleration region of the low velocity fluid was located inside the ejected stream. The velocity at which the fluid hits the target was relatively uniform. It indicated that the new jet mill was advantageous for obtaining a pulverized product having a narrower particle size distribution. Experimental results showed that the excessive size reduction was effectively reduced. The average mass fraction of the particles with the particle size of <30 μm was 19.0%, 30–150 μm was 72.8%, and >150 μm was 8.2%, meeting the requirement for titanium recycling from titanium-bearing blast furnace slag in industry. This study provides a feasible method for reducing particle size to a desired distribution to promote resource sustainable utilization and pollution reduction in an environmentally friendly way. Image 1069 • Particle size control is first identified as the key to Ti-BFS recycling. • One-time collision concept is put forward to control particle size of fracture. • Particle size controllable jet milling system is proposed and established. • Ti-BFS is crushed to the desired particle size distribution. [ABSTRACT FROM AUTHOR]