一种新型旋流混凝器结构参数优化

基于混凝沉降原理,对旋流器和涡流反应器的结构进行改进,提出了一种新型旋流混凝设备,该设备集混合、絮凝、沉降于一体,介绍了其结构及工作原理。基于计算流体力学(CFD)方法,运用CFX软件对其内部流场进行了数值模拟分析,依据产水率、速度和速度梯度进行功能评价,以此确定结构优化方法。研究结果表明:对底流口口径、入流口结构、接触面圆角进行优化可以有效改善旋流混凝器的性能;采用对称双切向入口,上部出口交界面采用倒角,底流口直径小于30 mm,可达到旋流混凝器的设计功能要求。

新型微涡流混凝器絮凝效果评价及数值模拟分析

针对海上油田返排液处理装置小型化、撬装化及高效化要求,研发设计了由若干特殊构造法兰单元组合构成的新型微涡流混凝器。通过现场试验考察了该装置的絮凝效果,并对混凝器内部流场进行了数值模拟分析。结果表明,污水经微涡流絮凝处理后,COD去除率>90%,悬浮物去除率>99%,出水COD和悬浮物含量达到《污水综合排放标准》(DB 12/356—2018)的三级排放标准。微涡流混凝器内流体呈现类似于圆管射流的流动特性,法兰构造显著增加了流体的湍流扰动,有效促进了凝聚效率的提升。

平行通道管间脉动试验过程中系统不稳定现象分析

在平行通道管间脉动试验过程中,系统出现了同频率等幅同相脉动和水锤现象。本文对此进行分析讨论的结果表明,回路系统中混凝器的存在容易引起系统的流动不稳定。用文丘里管流量计测量脉动流量除了应考虑测量系统的动态测量要求外,还必须对测量的平均流量和振幅加以修正。

煤矿水污染现状及其治理工艺的优化改进

针对煤矿产生的污水中包含有很多悬浮物和各类污染物,且原有的煤矿污水处理工艺已经不能应对现阶段的污水处理要求的问题。通过对煤矿开采过程中产生的水污染情况进行简要分析,并结合实际情况对污水工艺进行优化改进,添加了加药、高效混凝剂、高效旋流净化器等装置。经过该工艺处理后的污水中,各类污染物的含量均控制在了排放标准以内。将该方案应用到工程实践中,取得了较好的经济效益和生态效益。

Composite control for coagulation process with time delay and disturbances

A composite control scheme consisting of modepredictive control （MPC） and disturbance observer （DOB） iproposed to solve the control performance degradationproblem of the turbidity of the treated water in the presence osignificant changes in raw water quality, water flow rate andinternal model mismatch disturbances. The MPC is employedas a feedback controller for the coagulation process with alarge time delay. The DOB is adopted to estimate the severedisturbances in the turbidity control, such as large changes inraw water quality and water flow rate. The estimated valuesare applied for feed-forward compensation to rejecdisturbances. Finally, the disturbance rejection performancesfor step disturbances and time-varying disturbances in thenominal case and model mismatch case are tested. Thesimulation results illustrate that, compared with the MPCmethod, the proposed method can significantly improve thedisturbance rejection performance in the turbidity control othe treated water, no matter if in the presence of externadisturbances or internal model mismatch disturbances.

矿山开采水污染现状及治理工艺优化研究

矿产资源是社会主要的能源之一,为了提升人们的生活水平,近些年来我国进行了大范围地开采。同时也出现了矿山生产所产生的污水问题,由于其生产的污水中包含了大量的污染物与悬浮物,如果还采用传统的污水治理技术,无法满足如今我国的生态建设与发展的时代要求,对矿山开采水污染的现实情况进行分析,对其治理的生产工艺进行优化与提升有深远的价值和意义。从工艺的改进方面来看,在污水的治理中添加高效混凝剂、添加药剂、高效旋流净化器等净化装置。通过这样的工艺进行污水处理,可有效将污染物的水含量控制在生态排放的标准内。将这样的治理方案应用都实际的工程实践中,会对企业的经济效益与全民的生态发展产生巨大的作用。

THE DESIGN AND ACCOMPLISHMENT OF SHOTCRETE ROBOT

The design and accomplishment of shotcrete robot is presented in this paper. This shotcrete robot is the first robot for underground coal mine in our country. It is a specific machine used for spraying concrete in underground coal mine. It has many advantages such as simple structure convenient operation and high reliability. The on-site experiments indicate that the sprayed layer is even, at the same time, the quantity of rebound and dust content decrease largely. The robot can satisfy the requirement of shotcrete process completely.

Corrosion risk assessment of chloride-contaminated concrete structures using embeddable multi-cell sensor system

Monitoring the service condition of concrete structures requires the quantitative assessment of properties and corrosion rate of structural steels surrounded by concrete.A multi-cell sensor system that included a reference electrode,a chloride content sensor,a macrocell current unit and an electrical resistance measurement unit was developed.This system provided the following important electrochemical data in the cover-zone concrete on site:open circuit potential,macrocell current from anodes to cathode,chloride profile,concrete resistance and corrosion rate of built-in anodes.The experimental results show that the macrocell current increases when the chloride content in concrete is higher.Thus,monitoring the chloride content is a good method for monitoring the corrosion state.The chloride ion content and cover depth are the key factors that affect the electrical resistance of concrete.Without considering the temperature and time,a simplified model of the instantaneous corrosion rate of steel rebar in a concrete structure based on the measured chloride contents and concrete resistance was proposed.The test results further prove the reliability of this simplified predicting model.

Performance-based passive control analysis of adjacent structures:Optimization of Maxwell dampers

The performance-based passive control analysis of the Maxwell dampers between one 10-story and one 6-story adjacent RC frames is conducted in this work.Not only the optimal parameters but also the optimal arrangements of the Maxwell dampers are proposed based on the optimal target of making the total exceeding probability of the adjacent structures to be minimal.The applicability of the analytical expressions of the Maxwell damper damping parameters under different seismic performance targets are firstly examined and then the preferable damping parameters of the Maxwell dampers are proposed through the extensive parametric studies.Furthermore,the optimal arranging positions and optimal arranging numbers of the Maxwell dampers between the adjacent buildings are derived based on a large number of seismic fragility analyses,as well.The general arranging laws of the Maxwell dampers between the adjacent buildings are generated based on the discussion of the theoretical method through the simplified plane model.The optimal parameters and optimal arrangement of the Maxwell dampers presented make both the adjacent structures have preferable controlled effects under each seismic performance target which can satisfy the requirements of multi-performance seismic resistance of the modern seismic codes.

Reconstruction of an Expert＇s Decision Making Expertise in Concrete Dispatching by Machine Learning

Finding the optimum solution for dispatching in concrete delivery is computationally intractable because it is a NP-hard （non-deterministic polynomial-time hard） problem. Heuristic methods are required to obtain satisfactory solutions. Inefficiencies in mathematical modeling still make concrete dispatching difficult to solve. In reality, complex dispatching systems are mostly handled by human experts, who are able to manage the assigned tasks well. However, the high dependency on human expertise is a considerable challenge for RMC （ready mixed concrete） companies. In this paper, a logical reconstruction of an expert＇s decision making is achieved by two machine learning techniques： decision tree and rule induction. This paper focuses on the expert dispatcher＇s prioritization of customer orders. The proposed method has been tested on a simulation model consisting of a batch plant and three customers per day. The scenarios generated by the simulation model were given to a dispatch manager who was asked to prioritize the customers in each day. The scenarios and the decisions were then input to the machine learning programs, which created generalizations of the expert＇s decisions. Both decision trees and rules approach 80% accuracy in reproducing the human performance.

A reconfigurable active-G_m-RC filter formultistandard wireless receivers

A 4th-order low-pass filter （LPF） based on active-Gm-RC structure for multi-standard system application is presented in this paper. The performances of LPF are controlled by a 1-bit control- voltage, and the cut-off frequency, channel selectivity, and linearity of the proposed filter can be reconfigured accordingly. In order to improve the accuracy of the cut-off frequency, a binary-weigh- ted switched-capacitor array is employed as the auto-tuning circuits to calibrate the RC-time con- stant. Fabricated in TSMC 0. 18μm RF CMOS process, the proposed LPF achieves a measured cutoff frequency of 1.95 and 12.3MHz for WCDMA and GPS/Galileo application with a bandwidth de viation less than 4%. The measured l dB compression points are -3.0dBm and -5.1 dBm respectively for different modes. The core circuit of LPF consumes l mW and 1.6mW for WCDMA and GPS/Galileo respectively. And the proposed LPF occupies an area of 0.78ram2.

Identification of Connection Flexibility Effects Based on Load Testing of a Steel-Concrete Bridge

In the case of composite girders, an effective cooperation of both parts of the section is influenced by deformability of connectors. Limited flexural stiffness of welded studs, used commonly in bridge structures, does not provide full interaction of a steel beam and a concrete slab. This changes strain distribution in cross-sections of a composite girder and results in redistribution of internal forces in steel and concrete element. In the paper partial interaction index defined on the basis of a neutral axis position, which can be used for verification of steel-concrete interaction in real bridge structures rather than in specimens is proposed. The range of the index value changes, obtained during load testing of a typical steel-concrete composite beam bridge, is presented. The investigation was carried out on a motorway viaduct, consisting of two parallel structures. During the testing values of strains in girders under static and quasi-static loads were measured. The readings from the gauges were used to determine the index, characterizing composite action of the girders. Results of bridge testing under movable load, changing position along the bridge span is presented and obtained in-situ influence functions of strains and index values are commented in the paper.

Prediction of Compressive Strength Using Ultrasonic Pulse Velocity for CLSM with Waste LCD Glass Concrete

The purpose of this paper is to develop a prediction model of WGCLSM （waste LCD （liquid crystal display） glass controlled low strength materials） concrete, the relationship between UPV （ultrasonic pulse velocity） and compressive strength, UPV-strength model. The power function was used to perform the nonlinear-multivariate regression analysis of UPV with water-binder ratio （w/b）, curing age （t） and waste glass content （G） in our previous study. Test results show that the compressive strength increases with UPV and approach to a linear relationship. Thus, the UPV-strength model was established by linear-multivariate regression analysis and the compressive strength evaluated by ultrasonic pulse velocity. The calculated results are in accordance with the laboratory measured data ultrasonic pulse velocity and compressive strength. In addition, the statistical analysis shows that the coefficient of determination R2 and the MAPE （mean absolute percentage error） were from 0.916 to 0.951 and 12.6% to 15.1% for the compressive strength, respectively. The proposed models are highly accurate in predicting the compressive and ultrasonic pulse velocity of WGCLSM concrete. However, with other ranges of mixture parameters, the predicted models must be further studied.

Numerical simulation of heat transfer process in cement grate cooler based on dynamic mesh technique

A grate cooler is key equipment in quenching clinker and recovering heat in cement production. A two-dimensional numerical model based on a 5000 t/d cement plant is proposed to for a study on the gas-solid coupled heat transfer process between the cooling air and clinker in a grate cooler. In this study, we use the Fluent dynamic mesh technique and porous media model through which the transient temperature distribution with the clinker motion process and steady temperature and pressure distribution are obtained. We validate the numerical model with the operating data of the cooling air outlet temperature. Then, we discuss the amount of mid-temperature air outlet and average diameter of clinker particles, which affect the heat effective utilization and cooling air pressure drop in clinker layer. We found that after adding one more mid-temperature air outlet, the average temperature of the air flowing into the heat recovery boiler increases by 29.04℃ and the ratio of heat effective utilization increases by 5.3%. This means heat recovery is more effective on adding one more mid-temperature air outlet. Further, the smaller the clinker particles, the more is the pressure drop in clinker layer; thus more power consumption is needed by the cooling fan.