Water Environment Improvement of Zhongdong River by Water Diversion and Distribution in Hangzhou

As the development of city economy,Zhongdong River in Hangzhou was seriously polluted,with the worst water quality.In order to obtain the effect of water diversion and distribution from Qiantang River on the water quality of Zhongdong River,7-year continuous monitoring was conducted,which was at the fixed stations before and after the water diversion and distribution.After the water diversion project,the dissolved oxygen concentration of the river water was one to two times higher than before,and the ammonia nitrogen and total phosphorus decreased by 60%and 65%,respectively.When increased the amount of water diversion,the dissolved oxygen concentration of the river water elevated by 13%,and the ammonia nitrogen,total phosphorus and potassium permanganate index decreased by 8%,3%and 14%,respectively.The reason for the river water pollution was contributed to the combined sewer system and riverway sludge,especially during the rainfall,the dissolved oxygen concentration of Zhongdong River sharply declined by 95%,while the ammonia nitrogen and total phosphorus increased by 90%and 87%,respectively.The research results could provide theoretic basis for sustainable improvement of Zhongdong River water quality and river management department making the related regulations and policies.

Numerical simulation of operation performance on production and injection of a double well geothermal system in Kailu Basin, Inner Mongolia

Inner Mongolia is abundant in geothermal resources,but the development and utilization of medium-depth geothermal resources for clean heating in winter is still in the preliminary stage compared with the neighboring provinces.In this paper,a recently developed geothermal heating system using the Mesozoic sandstone reservoirs in Baokang of Kailu Basin,Eastern Inner Mongolia was investigated,a threedimensional geological model of a pair of production and injection well was established,and numerical simulations on the long term operation performance were conducted and verified by pumping test and water level recovery test data.The effects of flow rates,the direction of wells,injection temperature and ratios on the flow field and water level in the thermal reservoir were analyzed.The results show that considering a 30-year operation period and a production rate from 90 m^(3)/h to 110 m^(3)/h,the optimum well spacing can be increased from 225 m to 245 m,with an average value of 235 m.With the decrease of the injection temperature,the cold front of the injection water has an increasing influence on the temperature in the production well.A complete injection or the principle of production according to injection is recommended in order to maintain the long-term operation stability.In addition,the location of the injection well should be arranged in the downstream of the natural flow field.The present results can provide a useful guide for the optimum design and performance prediction of geothermal wells,thus maintaining the production and injection balance and promoting the sustainable development and utilization of medium-depth and deep geothermal resources.

Physiological and Biochemical Responses of Zizania latifolia to Traditional Chinese Medicine Wastewater

Effects of traditional Chinese medicine wastewater treatment on the physiological and biochemical indexes( such as TTC,Pro,GSH,MDA,SOD,POD,CAT,and PAL) of Zizania latifolia were investigated under four concentrations of medicine wastewater. The results showed that under the stress of traditional Chinese medicine wastewater,the contents of GSH,MDA and Pro had different degrees of increase,which would promote the increasing of superoxide anion. Meanwhile,the activities of root,SOD,POD,CAT and PAL also increased with the concentration of traditional Chinese medicine wastewater. Therefore,Z. latifolia had very strong anti-adversity abilities and tolerances to traditional Chinese medicine wastewater and can be used as one of the constructed wetland plants treating medicine wastewater.

Simulation of heat transfer performance using middle-deep coaxial borehole heat exchangers by FEFLOW

Due to its large heat transfer area and stable thermal performance,the middledeep coaxial borehole heat exchanger(CBHE)has become one of the emerging technologies to extract geothermal energy.In this paper,a numerical modeling on a three-dimensional unsteady heat transfer model of a CBHE was conducted by using software FEFLOW,in which the model simulation was compared with the other studies and was validated with experimental data.On this basis,a further simulation was done in respect of assessing the influencing factors of thermal extraction performance and thermal influence radius of the CBHE.The results show that the outlet temperature of the heat exchanger decreases rapidly at the initial stage,and then tended to be stable;and the thermal influence radius increases with the increase of borehole depth.The heat extraction rate of the borehole increases linearly with the geothermal gradient.Rock heat capacity has limited impact on the heat extraction rate,but has a great influence on the thermal influence radius of the CBHE.When there is groundwater flow in the reservoir,the increase of groundwater velocity will result in the rise of both outlet temperature and heat extraction rate.The heat affected zone extends along with the groundwater flow direction;and its influence radius is increasing along with flow velocity.In addition,the material of the inner pipe has a significant effect on the heat loss in the pipe,so it is recommended that the material with low thermal conductivity should be used if possible.

Monitoring actual performance of ground source heat pump system using GPRS-based data transmission: A case analysis in Tangshan

The energy efficiency monitoring is an essential precondition for ground source heat pump system's controlling and energy saving operation. Based on the data monitoring applied in the school building, this work is focused on the parameters acquisition and operation analysis of the GSHP system in Tangshan. Results show the average COPs(coefficient of performance) are2.85 and 2.70 in summer and winter, respectively, and heat(cold) unbalance underground existed after whole year operation. The analysis of data also indicates that the direct borehole air-conditioning saved some power consumption obviously in the early stage of summer and energy saving of the GSHP system depended remarkably on its operation and management level. Besides the observation points of ground temperature are laid for a large-scale GSHP system, and the hydraulic balance of the pipes group needs to be concerned specially in safeguarding better reliability.

Numerical study of macroscopical drainage process in fabricating foamed aluminum using microscopical method

The velocity field in a single Plateau border（PB） of the aluminum foam in the drainage process is studied using a mathematical model for the flow inside a microchannel.We show that the liquid/gas interface mobility characterized by the Newtonian surface viscosity has a substantial effect on the velocity inside the single PB.With the same liquid/gas interfacial mobility and the same radius of the curvature,the maximum velocity inside an exterior PB is about 6～8 times as large as that inside an interior PB.We also find a critical value of the interfacial mobility in the interior PB.For the values greater and less than this critical value,the effects of the film thickness on the velocity in the PB show opposite tendencies.Based on the multiscale methodology,with the coupling between the microscale and the macroscale and the results obtained from the microscopical model,a simplified macroscopical drainage model is presented for the aluminum foams.The comparisons among the computational results obtained from the present model,the experimental data quoted in the literature,and the results of the classical drainage equation show a reasonable agreement.The computational results reveal that the liquid holdup of the foams is strongly dependent on the value of the mobility and the bubble radius.

Investigation of Geometric Factors of Convex Platforms in the Flat Evaporator of Loop Heat Pipes

This paper investigated the influence of geometric factors of vapor groove structures on the performance of flat evaporator of a loop heat pipe system. COMSOL multiphysics software was employed to simulate the heat transfer in the evaporator with convex platforms of different shapes,sizes and area ratios(φ)between convex platforms and the heated surface. The maximum temperature and temperature distribution of each model were obtained. The results showed that the decrease of the size of platforms and the increase of φ can lower temperatures and improve temperature distribution homogeneity of the heated surface. Compared with circle and oval platforms,square platforms achieved lower temperature. The results also indicated that φ had the most significant impact on the performance of the evaporator.

Integrating BIM and machine learning to predict carbon emissions under foundation materialization stage:Case study of China’s 35 public buildings

For the significant energy consumption and environmental impact,it is crucial to identify the carbon emission characteristics of building foundations construction during the design phase.This study would like to establish a process-based carbon evaluating model,by adopting Building Information Modeling(BIM),and calculated the materialization-stage carbon emissions of building foundations without basement space in China,and identifying factors influencing the emissions through correlation analysis.These five factors include the building function type,building structure type,foundation area,foundation treatment method,and foundation depth.Additionally,this study develops several machine learning-based predictive models,including Decision Tree,Random Forest,XGBoost,and Neural Network.Among these models,XGBoost demonstrates a relatively higher degree of accuracy and minimal errors,can achieve the RMSE of 206.62 and R2 of 0.88 based on testing group feedback.The study reveals a substantial variability carbon emissions per building’s floor area of foundations,ranging from 100 to 2000 kgCO_(2)e/m^(2),demonstrating the potential for optimizing carbon emissions during the design phase of buildings.Besides,materials contribute significantly to total carbon emissions,accounting for 78%e97%,suggesting a significant opportunity for using BIM technology in the design phase to optimize carbon reduction efforts.

Numerical simulation of impact and solidification of melting dust on spherical bead surface and experimental validation

The impact and solidification processes of single melting tin dust at the micron scale on a spherical bead were numerically studied with hot flue gas flow. The geometrical evolution of dust impacting on hot bead and spreading without solidification involved initial spreading, retraction and oscillation, and stabilizing. The increased impact angle was found to reduce maximum spread area, weaken retraction and oscillation, and raise steady spread area. Dust impacting on cold bead completely solidified after liquid spreading and solidification without retraction and oscillation. Increased impact angle raised solidification sliding distance, whereas it reduced solidification spread area. Then, the effects of bead temperature, dust inlet velocity and size on the sliding and spreading of dust were studied, and the results indicated that increasing bead temperature, dust inlet velocity and size could raise solidification sliding distance and solidification spread area. With the dusts continually impacting on the bed, a dust layer forms at the front of bead, being different from that of solid dust, which becomes thick firstly, and then spreads from bead front to sides.

Mechanisms of ultrafine particle formation during coal combustion in a new swirl modification device

A new swirl combustion device was designed and enhaneed,which realized the utilization of steel slag,achieved highly efficient and clean coal combustion,and simultaneously realized a fully elemental utilization of coal.The distribution laws of different sized particulate matter(PM)emission and the enrichment laws of elements in particles under diverse conditions(such as various excess air coefficients and different coal ratios)were systematically studied.The enrichments of PM under both non-staged and fuel-staged conditions were also investigated.The results indicated that fuel-staged combustion is more helpful in reducing PM emissions than non-staged combustion,and a suitable coal ratio is also beneficial for reducing PM emissions.The melted liquid steel slag drop captured the fly ash produced from pulverized combustion,thus reducing PM emission.The alkali metal elements(K,Na,and Mg),the trace elements(As and Ti).and S have an obvious enrichment tendency in PM]and PM2.5,A different coal ratio under fuel-staged combustion has a significant influence on the enrichment of Al,Si,Ca,and Fe in PM),whereas in PM2.5.PM4,and PM10,the effect of different coal ratios on the enrichment of each element is slight.

Experimental study on filtering mixed solid-liquid dust with a sliding granular bed filter

The filtration of mixed dust that included a small number of melted(liquid)particles was studied in an experimental granular bed filter(GBF).Results show that the collection efficiency of dust containing melted particles is higher than that of dust composed of solid particles but the pressure drop from the former is higher than that of the latter.The collection efficiency and pressure drop increase as the concentration of melted particles increases.A surface sliding GBF exhibits good comprehensive performance when filtering dust,especially dust containing a mix of solid and liquid particles.The effects of the gas temperature,gas velocity,sliding filter bed thickness,and sliding collector flux on filter performance were also examined.Based on the experimental results,correlations for the collection efficiency and pressure drop for mixed dust are presented.