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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: 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: 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]

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]

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]

There are four taper ridge waveguide couplers with characteristic impedance of 50 ohms operating in pulse mode at China Spallation Neutron Source (CSNS) Drift Tube Linac (DTL) section. Multipacting (MP) in couplers may be a factor limiting the steady operation of the accelerator. In this paper, MP barriers in the critical area of the coupler are estimated according to the parallel-plate model firstly. Second, we present a detailed numerical simulation results obtained by the TRK and PIC Solver in CST PS Studio. Furthermore, MP zones encountered during the conditioning process are performed. Finally, a good agreement of the analytical predictions, the numerical simulation results and the experimental data have been found. [ABSTRACT FROM AUTHOR]

In northern China, transmission power system and district heating systems (DHSs) are directly connected by large-capacity combined heat and power (CHP) units, which composes the wide-area integrated power and heat system (IPHS). For better wind power accommodation, it is crucial to explore the operational flexibility of each local DHS in the wide-area IPHS. This paper investigates the available electric flexibility from the DHS through the CHP units and the heat-to-power devices. A flexibility region method is proposed to accurately formulate the DHS's flexibility in terms of power capacity and energy capacity, with a special emphasis on the temporal-coupling feature which is usually oversimplified in the existing studies. Then, solving algorithm is discussed to construct the polytope-form flexibility region, which provides an explicit and concise description of the electric flexibility from the DHS. Flexibility indicators are also developed for flexibility potential quantification. Further, a practical IPHS dispatch scheme is designed, which performs the wide-area power dispatch and the local-area heat dispatch hierarchically. Numerical simulation demonstrates the effectiveness of the flexibility region method in assessing the DHS's electric flexibility and performing the IPHS dispatch, as well as the benefit of coordinating the flexibility from multiple DHSs for wide-area wind power accommodation. • The temporal-coupling feature of the heating system's flexibility is illustrated. • Flexibility region is proposed to model the electric flexibility of heating system. • Indicators are proposed to assess heating system's flexibility potential. • A wide-area integrated heat and power dispatch scheme is developed hierarchically. • Heating system provides considerable time-series flexibility for power system. [ABSTRACT FROM AUTHOR]