Effects of the Component and Fiber Gradient Distributions on the Strength of Cement-based Composite Materials

The effects of the component gradient distribution at interface and the fiber gradient distribution on the strength of cement-based materials were studied. The results show that the flexural strength and compressive strength of the mortar and concrete with interface component and fiber gradient distributions are obviously improved. The strengthes of the fiber gradient distributed mortar and concrete (FGDM/C) are higher than those of fiber homogeneously distributed mortar and concrete (FHDM/C). To obtain the same strength, therefore, a smaller fiber volume content in FGDM/C is needed than that in FHDM/C. The results also show that the component gradient distribution of the concrete can be obtained by means of multi-layer vibrating formation.

Robust distributed controller design of rotational single-link smart materials beam

A dynamic modelling and controller design were presented for a single-link smart materials beam, a flexible beam bonded with piezoelectric actuators and sensors for better control performance. Taking into account bounded disturbances, a robust distributed controller was constructed based on the system model, which was described by a set of partial differential equations (PDEs) and boundary conditions (BCs) . Subsequently, a finite dimensional controller was further developed, and it was proven that this controller can stabilize the finite dimensional model with arbitrary number of flexible modes. Keywords Dynamic modelling - Robust distributed controller - Flexible beam - Smart material

Exploration on electrical resistance tomography in characterizing the slurry spatial distribution in cemented granular materials

This study investigated the application of electrical resistance tomography(ERT)in characterizing the slurry spatial distribution in cemented granular materials(CGMs).For CGM formed by self-flow grouting,the voids in the accumulation are only partially filled and the bond strength is often limited,which results in difficulty in obtaining in situ samples for quality evaluation.Therefore,it is usually infeasible to evaluate the grouting effect or monitor the slurry spatial distribution by a mechanical method.In this research,the process of grouting cement paste into high alumina ceramic beads(HACB)accumulation is reliably monitored with ERT.It shows that ERT results can be used to calculate the cement paste volume in the HACB accumulation,based on calibrating the saturation exponent n in Archie’s law.The results support the feasibility of ERT as an imaging tool in CGM characterization and may provide guidance for engineering applications in the future.

Properties of Rapid Hardening Controlled Low Strength Material Made of Recycled Fine Aggregate from Urban Red Brick Construction Waste

In some cases of emergency backfill engineering projects, traditional backfill materials cannot meet the requirements of fast construction due to their long curing time. This study presents a new kind of rapid hardening controlled low strength material, which utilizes both rapid hardening sulphoaluminate cement and recycled fine aggregate from urban red brick construction waste. Totally, sixteen mixtures were prepared for the experiment with different cement-to-sand ratios and water-to-solid ratios. The flowability and bleeding rate of fresh mixture were measured to evaluate its workability, and the compressive strength of hardened mixture was tested to evaluate its rapid hardening and mechanical properties. Test results indicate that rapid hardening controlled low strength material containing recycled fine aggregate from urban red brick construction waste can achieve the desirable flowability, but the bleeding rate increases with the increase of flowability. In addition, 2-hour compressive strength can reach 0.08 - 0.12 MPa, and 4-hour compressive strength is 0.32 - 1.54 MPa, which can meet the requirements of emergency backfill construction. At last, based on the derived compressive strength, a fitting model for predicting compressive strength evolution of this new rapid hardening backfill material is developed, which fits accurately with these experimental data.

Grinding Characteristics of Multi-component Cement-based Material

The grinding characteristics of two or multi-component material of cli nker with limestone, blast furnace slag and fly ash were studied. Investigation was carried out on the particle size distribution, the Blaine fineness and the s ieve residue of the separate and interground products. The relative contents of clinker and limestone in different size fractions of the interground product wer e examined, and the interaction of two components, which have different grindabi lities, was analyzed. The results show there exists a selective grinding effect during intergrinding, one component can help or hinder the grinding of the other . Making good use of this interaction appropriately not only enhances the grinda bilities of two or multi-component mixtures, which can promote the grinding pro cess of clinker with industrial wastes, but also improves their particle size di stribution and properties.

进程可编辑的NCM前驱体洗分装置自动控制系统的设计与应用

NCM三元镍钴锰正极材料与钴酸锂正极材料相比,具有成本低、环保性好、容量高、循环性能好等优势,被称为是第三代锂离子电池正极材料。从三元湿料到干料过程中,主要包括过滤、陈化、洗涤、吹干、输送等工序。本文结合实际项目,介绍一种以板框压滤机为洗分工序的主体设备,配合阀站、仪表和控制系统,经由螺旋输送至干区直至包装,洗分工序涉及进浆、压榨、洗涤、吹干、输送等工序。该系统克服了传统洗分方式需要大量的现场人员干预,操作繁琐、指标不稳定的缺点,在实际应用中取得了良好的使用效果,实现了三元锂离子电池正极前驱体洗分系统的无人监管、自动控制,稳定了生产工艺流程,减少了现场人员工作量。

适合矿井防治水的水泥基化学复合材料研究

深层煤矿井开采过程中极易出现巷道涌水等事故,为了解决传统水泥基支护材料硬脆性强、韧性差以及抗渗能力弱的问题,以醋酸乙烯酯和聚乙烯醇为主要原料,在乳化剂OP-10和SDS的作用下,制备了一种改性聚合物乳液PVEA-1,并将其与水泥、粉煤灰、砂和PVA纤维等材料相结合,制备出了一种新型水泥基化学复合材料。考察了水泥基化学复合材料的基本物理性能、力学性能和抗渗性能,结果表明,改性聚合物乳液PVEA-1能够有效提高水泥基化学复合材料的流动度和保水率,并且随着PVEA-1加量的不断增大,水泥基化学复合材料的抗压强度逐渐降低,抗折强度先升高后降低,压折比先降低后升高,吸水率逐渐降低。当PVEA-1的加量为8%时,水泥基化学复合材料的综合性能较好,具有较高的韧性和抗渗能力,能够作为深层煤矿井防治水的支护材料使用。

酒厂用起重机智能化控制的应用

针对当前酿酒行业普遍存在的起重机智能化应用不足的问题,本文旨在通过对传统酿酒车间中使用的起重机进行智能化操作技术和自动定位技术的应用与改造,利用现代技术检测、分析酒糟堆表面的三维扫描数据信息情况来改善投料操作,有效提高起重机的工作效率,对现代酒厂中智能化控制起重机的安全运行与日常维护提供有效技术支持。

荒漠化治理林草自动种植车

我国深受荒漠化影响,众多人口遭受其害,风沙危害也日益严重。为解决这些问题,设计了一种荒漠化治理林草自动种植车。该装置的核心是行走车体,其上巧妙设置了挖洞机构、平移机构、出料机构、取料与放料机构以及填埋机构等部分。该种植车可全自动开展荒漠化治理工作,不仅能解放大量劳动力,还能节省劳动成本;同时,能合理利用水资源,提高树苗的存活率;此外,该装置能植树造林,有效缓解土地沙漠化。

原燃料自动取制样与检测系统在冶金行业的应用

针对目前钢铁企业进厂原燃料质量检验面临的问题,介绍了一种自动取制样与检测系统,该系统主要由自动采样单元、样品自动分拣单元、制样单元、检测单元、存储单元以及集控系统等组成。通过检测中心集控系统与各单元及厂区物流信息网络的交互关联,实现了全厂原燃料质量检验的集成化管理与监督,对各大钢厂处理同类型问题具有一定参考价值。

基于校企合作的活页式教材的开发与实践

机械设备装配与自动控制专业的课程实操性强,所用教材存在教材形式单一、配套信息化资源不全面不丰富、学生参与度较低等问题,因此,新形态教材的开发与建设显得尤为迫切。结合机械设备装配与自动控制专业的课程要求,以机修钳工技能训练课程为例,对接国家职业技能标准,以校企合作为契机,就如何开发活页式教材展开论述,以满足培养机械设备装配与自动控制专业高素质技能型人才的教学需要。

基于PLC的物料分拣控制系统设计

针对小型农用滚筒筛类产品中配件生产过程实现自动化而进行了分拣系统的研究,系统由进料模块、物料输送模块及分拣模块三部分组成,每一个模块均由气动装置作为执行单元,并选用各类传感器来提供工件的位置、状态、颜色等信号,通过PLC实现对整个系统模块的控制,实现对不同材质、不同颜色物料的自动分栋。运行结果表明,该系统分拣正确率高、运行稳定,可大大提高企业的生产效率,减少人工劳动强度。

循环流化床灰渣制备胶凝材料综述

循环流化床(Circulating Fluidized Bed,CFB)灰渣是一种全新的燃煤固废,为了促进其在胶凝材料领域的应用,本文综述了不同CFB灰渣制备胶凝材料的方法和制约条件。文献研究显示,较高的火山灰活性和水硬性让CFB灰渣常被用作辅助胶凝材料,但体系SO_(3)质量分数常控制为小于3.5%。当CFB灰渣掺量不超过20%时,可与粉煤灰、矿粉等复配制备生态水泥。用CFB灰渣制备蒸压加气混凝土时,当体系SO_(3)质量分数超过5.0%时,产品中托贝莫来石生成量下降、吸湿特性增强。低硫低钙CFB灰渣可制备地质聚合物,但体系总CaO超过3.5%,地聚反应减少、水化反应增多。CFB灰渣无论新陈,均可以用来制备可控低强度材料。此外,本文也指出了针对CFB灰渣的理论和应用研究方向。

动车段检修物料精准配送与过轨AGV的研究

针对动车组检修生产线存在物料配送不及时、不准确,以及AGV小车无法有效应对厂区内的沟槽和轨道等问题,设计了基于节拍式、量份式叫料系统的精准配送方案以及过轨AGV小车,在有效解决上述问题的同时,降低了生产成本,提高了动车组检修效率。

提高湿法磷酸浓缩装置运行周期的改进方法

本研究旨在提高湿法磷酸浓缩装置的运行周期,以满足日益增长的磷酸需求,并减少生产过程中的资源浪费。通过对现有湿法磷酸浓缩装置的性能进行深入分析,提出了一种综合的改进方法,包括材料优化、工艺参数调整和自动控制系统的优化。经过实验验证和数值模拟,成功地延长了装置的运行周期,减少了维护次数,提高了生产效率。本研究为湿法磷酸浓缩装置的可持续运营提供了有力支持,对于磷酸工业的发展具有重要意义。

物料分拣PLC控制系统的设计

阐述一个基于可编程控制器PLC的自动分拣系统,该系统由下料、送料、传送装置和分拣模块组成。通过传感器检测出物料所对应的颜色、材质等特点,依次实现物料的分拣。

基于PLC控制的耐火材料自动送料机设计研究

本文旨在针对耐火材料行业,设计一种高效、可靠的物料输送自动送料机,以提高生产效率和加工质量。通过合理设计总体结构、优化送料机构和驱动装置、科学布置传感器,并采用西门子S7-1200系列PLC作为控制核心,实现了自动送料功能。经过严谨的性能测试,评估了该送料机在实际工作中的生产效率、加工精度和稳定性等关键指标,结果表明其各项性能均达到或超出预期目标,优于同类产品的平均水平,展现出良好的工业应用前景。

浅谈硫磺回收装置设计过程中针对硫化氢介质的防范措施

石油化工生产中,往往伴随有毒有害介质如硫化氢的生成。本文针对硫化氢各种危害情况,简单阐述了在硫磺回收装置设计过程中针对其泄漏所作的部分防范措施,详细描述了密闭排放等方式。供化工企业或行业同仁参考、讨论。

Development and Evaluation of a New Nanometer Based Spacer NMS-I

In view of the inadequate cementing quality in the cementation for long isolation intervals ofoil and gas wells, and considering the field practice in Tarim Oilfield, a nanometer material LC-212 was introduced as the base stock to experimentally develop a new spacer system NMS-I, in combination with other materials, including a chemical gel plugging agent, carboxymethyl cellulose and barite. Experimental results indicated that the system had a wide adjustable range of density, good rheological property, static stability and compatibility with cement slurry. It also showed no flocculating or thickening effect on the water-base drilling fluid and low-density cement system. Meanwhile, the capacity of lost circulation control and the influence of the spacer on the second interfacial cementing strength were evaluated by a self-made lost circulation simulator and shearing test facility. The results showed that the spacer had favorable plugging and flushing effect, and the second interfacial cementing strength can be greatly improved. Moreover, based on the experiments, the mechanisms of spacer function were analyzed. The results obtained from the investigation offer a novel approach to resolving some practical problems in cementing jobs.

中医药产业发展现状与存在问题分析——以甘肃省定西市为例

以甘肃省定西市中医药产业发展现状为例,对中医药产业发展过程中出现的问题进行梳理分析。近年来,定西市中医药产业发展成效明显,表现在中药材良种繁育初见成效,药材种植面积稳定增长,中药材加工能力不断提升,中药材仓储交易规模持续增大,中药材质量标准体系逐步建立,以及中医药康养产业正在兴起。而中医药产业发展过程中呈现的中药材种业专业化水平不高、中医药产业科技化程度不高、中药材流通溯源体系不全、中医药文化塑造宣传不足等问题,亟需通过政府的主动担当、积极引导,协调多方合作,制定相关政策以有效推进中医药产业的发展壮大。通过分析定西市中医药产业发展的现状与存在问题,以期为全国其他地方中医药产业的发展提供借鉴。