Pressure stimulated current in progressive failure process of combined coal-rock under uniaxial compression:Response and mechanism

Effective monitoring of the structural health of combined coal-rock under complex geological conditions by pressure stimulated currents(PSCs)has great potential for the understanding of dynamic disasters in underground engineering.To reveal the effect of this way,the uniaxial compression experiments with PSC monitoring were conducted on three types of coal-rock combination samples with different strength combinations.The mechanism explanation of PSCs are investigated by resistivity test,atomic force microscopy(AFM)and computed tomography(CT)methods,and a PSC flow model based on progressive failure process is proposed.The influence of strength combinations on PSCs in the progressive failure process are emphasized.The results show the PSC responses between rock part,coal part and the two components are different,which are affected by multi-scale fracture characteristics and electrical properties.As the rock strength decreases,the progressive failure process changes obviously with the influence range of interface constraint effect decreasing,resulting in the different responses of PSC strength and direction in different parts to fracture behaviors.The PSC flow model is initially validated by the relationship between the accumulated charges of different parts.The results are expected to provide a new reference and method for mining design and roadway quality assessment.

Multi-output Gaussian Process Regression Model with Combined Kernel Function for Polyester Esterification Processes

In polyester fiber industrial processes,the prediction of key performance indicators is vital for product quality.The esterification process is an indispensable step in the polyester polymerization process.It has the characteristics of strong coupling,nonlinearity and complex mechanism.To solve these problems,we put forward a multi-output Gaussian process regression(MGPR)model based on the combined kernel function for the polyester esterification process.Since the seasonal and trend decomposition using loess(STL)can extract the periodic and trend characteristics of time series,a combined kernel function based on the STL and the kernel function analysis is constructed for the MGPR.The effectiveness of the proposed model is verified by the actual polyester esterification process data collected from fiber production.

Pollutants removal and simulation model of combined membrane process for wastewater treatment and reuse in submarine cabin for long voyage

A laboratory scale test was conducted in a combined membrane process （CMP） with a capacity of 2.91 m3/d for 240 d to treat the mixed wastewater of humidity condensate, hygiene wastewater and urine in submarine cabin during prolonged voyage. Removal performance of chemical oxygen demand （COD）, ammonia nitrogen （NH4^＋-N）, turbidity and anionic surfactants （LAS） was investigated under different conditions. It was observed that the effluent COD, NH4^＋-N, turbidity and LAS flocculated in ranges of 0.19-0.85 mg/L, 0.03-0.18 mg/L, 0.0-0.15 NTU and 0.0-0.05 mg/L, respectively in spite of considerable fluctuation in corresponding influent of 2120-5350 mg/L, 79.5-129.3 mg/L, 110-181.1NTU and 4.9-5.4 mg/L. The effluent quality of the CMP could meet the requirements of mechanical water and hygiene water according to the class I water quality standards in China （GB3838-2002）. The removal rates of COD, NH4^＋-N, turbidity and LAS removed in the MBR were more than 90%, which indicated that biodegradation is indispensable and plays a major role in the wastewater treatment and reuse. A model, built on the back propagation neural network （BPNN） theory, was developed for the simulation of CMP and produced high reliability. The average error of COD and NH4^＋-N was 5.14% and 6.20%, respectively, and the root mean squared error of turbidity and LAS was 2.76% and 1.41%, respectively. The results indicated that the model well fitted the laboratory data, and was able to simulate the removal of COD, NH4^＋-N, turbidity and LAS. It also suggested that the model proposed could reflect and manage the operation of CMP for the treatment of the mixed wastewaters in submarine.

Metallurgical Reaction Characteristic for the Combined Blowing Process of Top-Bottom Blown Oxygen and Bottom Blown Natural Gas

The experiment was carried out in a combined blowing converter.The natural gas was supplied as the cooling medium for the bottom lance.The blow- ing practice of medium P hot metal (0.30-0.85% [P]) indicated that with better stirring at the bottom of the converter and lower P_(CO),this steelmgking process was favorable to reduce the amount of [C] and [O] and increase the (P_2O_5)/[P]. The maximum rate of dephospborization might be high up to 0.0a5%/min and the P content in steel could be reduced to lower than 0.03% by single slag-forming operation.

Optimization of continuous electrocoagulation-adsorption combined process for the treatment of a textile effluent

The aims of this study is to design and optimize the functioning of a full continuous combined process based on electrocoagulaion-adsorption on crude Tunisian clay to treat a real textile effluent.The clay characterization shows that the used clay is a rich-smectite clay.The response surface methodology(RSM)technique based on Box-Behnken design(BBD)was used to optimize the process.At optimum conditions which are initial pH solution of 8.24,effluent flow rate of 0.5 L·min^(-1),voltage of 70 V,and added suspension of clay flow rate of 100 ml·min^(-1) the achieved color,chemical oxygen demand(COD)and total suspended solid(TSS)removal efficiencies were respectively 96.87%,89.77%and 84.46%with0.75 USD·m^(-3) as total cost.The additional laboratory experiments at optimum conditions agree with the predicted results,which confirm the accuracy and the capability of RSM to predict results in the defined space.Finally the designed process could be a good eco-friendly alternative to treat and reuse wastewater in industrial process with reasonable cost.

ANALYSIS OF SURFACE CRACK ON FORWARD EXTRUDING BAR DURING AXISYMMETRIC CUP-BAR COMBINED EXTRUSION PROCESS

In this paper, the kinematically admissible velocity field with surface crack on forward extruding bar is put forward during the axisymmetric cup-bar combined extrusion process, in accordance with the results of model experiments.On the basis of velocity field, the necessary condition for surface crack formation on the forward extruding bar is derived, with the help of upper bound theorem and the minimum energy principle. Meanwhile, the relationships between surface crack formation and combination of reduction in area for the part of forward and backward extursions relative residual thickness of billet (T/R0),frictional factor (m) or relative land length of ram and chamber are calculated during the extrusion process. Therefore, whether the surface crack on forward exturding bar occurs can be predicted before extruding the lower-plasticity metals for axisymmetric cup-bar combined extrusion process.The analytical results agree very well with experimental results of aluminium alloy LY12 (ASTM 2024) and LC4 (ASTM 7075).

The Integration of Vacuum Brazing into Heat Treatment - A Progressive Combined Process

The continuous constructive challenge to improve the functionality and efficiency of components always results in higher demands on production engineering, against the background of the generally increasing cost pressure. In many cases, you will just succeed in producing competitive and innovative products by combining and coupling of different procedures to an independent (hybrid) technology. The use of hybrid procedures for metal joining and heat treatment of metallic materials finds more and more industrial fields of application. Modern vacuum lines with integrated pressurized gas quenching are considered high-performance and flexible means of production for brazing and heat treatment tasks as well in the turbine industry as in the mould making and tool manufacturing industry. In doing so, the heat treatment is coupled with the brazing cycle in a combined process so that the brazing temperatures and soak times are adapted to the necessary temperatures and times for solution heat treatment and austeniting. This user-oriented article describes on the one hand examples of brazing of turbine components, but above all the practical experience from the plastics processing industry, where the requirement for a high-efficient cooling of injection moulding dies gains more and more importance. The combined procedure "Vacuum Brazing and Hardening" offers plenty of possibilities to produce mould inserts with an efficient tempering system in an economic way.

Full scale application of combined SBF-AS process for municipal wastewater treatment in small towns and cities in China

The combined submerged biofilm （SBF）-activated sludge （AS） process for treatment of municipal wastewater in a small city in China is described in this paper. The process exhibited high removal efficiencies for carbonaceous substances, nitrogen and phosphorus which mainly took place in the combined SBF-AS bioreactor. The SBF-AS bioreactor was divided into pre-anoxic, anaerobic, anoxic and aerobic zones from inlet to outlet, in which fixed biofilm carriers were packed. Excellent performance had been obtained under normal operating conditions in more than one year of operation in Dong’e municipal WWTP, Shandong province, with mean removal efficiencies of BOD5 934%, COD 88%, SS 92%, NH+4-N 821%, TP 75% and TN 667%, and quite high effluent quality such as BOD5 6 to 10 mg/L, COD 20 to 40 mg/L, SS 5 to 10 mg/L, TN 10 to 20 mg/L, NH+4-N 4 to 8 mg/L and TP 06 to 10 mg/L. The effluent was reused multi-purposely, such as toilet flushing, green belt watering and artificial lake pounding. Simultaneous nitrification and denitrification took place due to the DO gradient in biofilm in aerobic zone of the SBF-AS bioreactor, which made TN removal efficiency improved remarkably in system. Some activated sludge was returned from final clarifiers to the bioreactor for phosphorus removal. The process had the advantages of low investment and low operational/maintenance （O/M） costs, low sludge yield and was preferably employed in small towns and cities.

Effects of Combined Instantaneous High-Pressure and MediumTemperature on the Retention of Total Vitamin Cin Wax Gourd Juices

Based on the instantaneous high-pressure(IHP)produced by high-pressure single pole-cylinder pump, the effects of combining this pressure with medium temperature on the retention of total vitamin C(Vc)in wax gourd juices were investigated under 20 - 80 MPa, 35 - 58℃, pH 3. 0 - 6. 0 and processing time 0-8 min. Results showed that the loss of Vc increased with elevated processing temperatures(50 MPa, 4 min). When the temperature of raw juices was 35℃, the retention of total Vc was higher under 40 - 60 MPa than that under the pressure < 40 MPa or > 60 MPa, and it was up to 94%(4 min). The retention of total Vc decreases slowly within 6 min, but rapidly after 6 min. The pH can also influence the retention of total Vc, and this retention can come to a highest point at pH 6.0.

Effects of Combined Instantaneous High-Pressure and Medium Temperature on Peroxidase Activity in Wax Gourd Juices

Based on the instantaneous pressurization and depressurization produced by high pressure single pole cylinder pump and valve, the effects of the continuous processing on the peroxidase (POD) activity in wax gourd juices were investigated. Results showed that the processing factors such as pressure, temperature, pH and processing time are important to the POD activity. POD in crude juices could be inactivated apparently above 50 MPa(pH 4.6, 35℃, 4 min), and activated at 20 MPa ( P < 0.01). Its remarkable inactivation could also be observed at 45 and 55℃ (20 MPa, pH 4.6, 4 min), and the evident activation appears at the material temperature 35℃ ( P < 0.01). The pH 3.0 could destroy POD almost completely (20 MPa, 35℃, 4 min), while pH 6.0 could not influence apparently the POD activity in crude juices( P > 0.05). In addition, the rules of POD activity along with the treatment time are variational under different processing pressures. The higher the treating pressure is, the shorter the processing time is needed to inactivate POD.

Dechlorination by combined electrochemical reduction and oxidation

Chlorophenols are typical priority pollutants listed by USEPA (U.S. Environmental Protection Agency). The removal of chlorophenol could be carried out by a combination of electrochemical reduction and oxidation method. Results showed that it was feasible to degrade contaminants containing chlorine atoms by electrochemical reduction to form phenol, which was further degraded on the anode by electrochemical oxidation. Chlorophenol removal rate was more than 90% by the combined electro- chemical reduction and oxidation at current of 6 mA and pH 6. The hydrogen atom is a powerful reducing agent that reductively dechlorinates chlorophenols. The instantaneous current efficiency was calculated and the results indicated that cathodic reduction was the main contributor to the degradation of chlorophenol.

Heuristic Method for Job Shop Scheduling Problem with Combination Processing

A job shop scheduling problem with a combination processing in complex production environment is proposed. Based on the defining of ＂non-elastic combination processing relativity＂ and ＂virtual process＂, the problem can be simplified and transformed to a traditional one. On the basis of the dispatching rules select engine and considered factors of complex production environment, a heuristic method is designed. The algorithm has been applied to a mould enterprise in Shenzhen for half a year. The practice showed that by using the method suggested the number of delayed orders was decreased about 20% and the productivity was increased by 10 to 20%.

组合赋权法在卷烟机综合性能评价中应用

【目的】客观准确地评价卷烟机设备性能,从质量水平、消耗水平和效能水平3个维度出发,构建设备综合性能评价指标体系和组合赋权评价模型。【方法】利用最大熵原理给出最优组合系数和方案评价计算步骤。开展Topsis方法、层次分析法、熵值法和组合赋权法在卷烟机设备综合性能评价的实例分析和比较工作。【结果】4种方法具有显著正相关关系,评价结果满足一致性。组合赋权法与其他评价方法相比具有最优组合系数和误差平方和小优势。

铜火法冶炼废水处理实践

阐述了铜冶炼火法工艺发展状况,剖析了铜冶炼过程产生废水的主要环节,并对废水处理工艺及原理进行了梳理,分析了某铜冶炼企业废水产生节点、产生特点和组成成分;针对现有的废水处理技术和资源化利用提出了合理的建议。特别阐述了阳谷祥光铜业自主研发的旋浮铜冶炼技术、粗铜自氧化还原精炼技术、平行流电解技术,“硫化+石膏+中和”工艺和废水深度处理联合工艺特点,对采用火法冶炼工艺的铜冶炼企业的废水处理及资源化利用具有借鉴意义。

油水分离技术的研究进展

综述了含油废水的定义､油的存在形态､油水分离技术以及吸油材料的研究进展。油水分离技术包括物理分离法､化学分离法､物理化学分离法以及组合工艺等。阐述了各种油水分离技术的基本原理､流程和特点,综合比较分析发现,应依据含油废水中油品的性质及存在形式选择合适的油水分离技术,并且兼顾经济效益。组合工艺是油水分离的发展趋势;高性能低成本油水分离材料以及油水分离设备的研发是未来油水分离技术发展的重点。

医养服务机构质量评价指标体系的构建与初步应用

目的以“结构-过程-结果”理论为框架,构建医养服务机构质量评价指标体系并初步应用。方法基于文献研究、小组讨论、德尔菲法及层次分析法,确定评价指标体系和各指标权重。应用该指标体系在长沙市3家医养服务机构进行现场评价。结果共进行2轮函询,专家权威系数分别为0.915和0.927,协调系数分别为0.211和0.164,最终确定一级指标3个,二级指标13个,三级指标53个。评价指标体系的Cronbach'sα系数为0.786,平均内容效度指数为0.862。在3家医养服务机构进行的预调查效果较好。结论医养服务机构质量评价指标体系信度、效度较好。构建的指标科学、合理、实用性强,能有效评价医养服务机构质量并发现问题。

基于零排的高盐废水处理技术经济比选分析

高盐废水零排工艺中常有超滤、反渗透、MVR蒸发等工艺的组合,但因为零排的水平衡问题,其组合顺序影响投资规模和运行成本。以某资源化项目的废水零排处理工艺为例,对不同的工艺路线进行技术经济分析,研究发现直接采用MVR蒸发全量处理废水能耗过高,采用DTRO减量化后再蒸发结晶更经济,分析成果可为类似项目决策提供参考。

轴用VL形组合密封件装配工艺仿真研究及验证

橡塑组合密封是由橡胶圈和塑料密封环组成,安装过程中塑料环的变形对密封性能有重要影响。以轴用VL形组合密封为例,基于三维有限元仿真模型和可视化密封装配台架针对不同流程的装配工艺开展研究。利用有限元仿真还原密封圈装配过程,搭建可视化密封件装配台架,开展密封件装配试验,验证有限元仿真装配过程的准确性;提取密封界面接触压力、接触宽度等关键参数,评判密封性能;建立密封性能与装配工艺之间的关系,优化密封件安装、矫正工艺流程,解决装配过程随机化、经验化问题。试验结果表明:常温安装时密封面接触宽度要小于加温安装;对于轴用VL形组合密封,在相同介质压力条件下接触宽度越小则密封面接触压力越大,从而密封性能越好。因此可以得出常温装配时密封性能更优。

膜调控的头孢呋辛钠溶析-冷却耦合结晶成核介稳区测定及分析

溶析-冷却耦合结晶可以提高结晶产率的同时,降低溶析剂的消耗量,是一种高效的耦合分离过程。传统的溶析结晶传质的界面往往受到宏观混合规模的限制,传质调控通常为亚毫米级,容易爆发成核,导致结晶产品的纯度差、平均粒度小、晶体粒度分布宽,因而需要更精确的调节策略。本文提出了一种新型的膜辅助溶析-冷却耦合结晶的方法,应用于头孢呋辛钠的结晶过程研究。其中,聚四氟乙烯(PTFE)中空纤维膜作为精确添加溶析剂和高效混合的界面,实现过饱和度的均匀分布。为了对比膜辅助溶析-冷却耦合结晶和传统耦合结晶方式的调控效果,对膜辅助溶析-冷却耦合结晶过程进行更为精确的调控,分别测量了传统和膜辅助条件下溶析-冷却耦合结晶的头孢呋辛钠-水-乙醇体系的介稳区宽度,计算了成核动力学参数。使用响应面方法和理论模型分析了冷却速率、溶析剂添加速率和溶析剂组分对介稳区宽度的影响,并比较了传统结晶和膜辅助结晶的介稳区特征。结果表明,膜辅助溶析-冷却耦合结晶的成核级数和成核速率常数(n=2.07,kn=158.15)均小于常规耦合结晶(n=2.45,kn=493.22),成核动力学方面更加温和,可调控性更强。