Mixing potential: A new concept for optimal design of hydrogen and water networks with higher disturbance resistance

During the last decade, the design methods of hydrogen and water networks have been improved greatly. Since the resulting network structure featuring minimum utility consumption is not unique, other properties such as disturbance resistance have drawn more and more attention. In this article, a novel concept, Mixing Potential, is proposed to improve the disturbance resistance ability of the networks in the design stage. This concept originates from measuring the concentration fluctuation of a single sink, and could be calculated by its graphical and algorithmic definition, respectively. In addition, a sufficient condition for minimizing the Mixing Potential of a single sink has been proved. Based on this sufficient condition, a graphical and its corresponding algorithmic method are proposed to design the hydrogen and water networks with minimum utility consumption. Literature examples illustrate that the disturbance resistance ability of the network can be improved by adjusting the satisfying order of sinks. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3762–3772, 2014     

基于改进型延时观测器的电热炉温度复合控制方法

电热炉温控系统自身具有大时滞和大惯性的特点,常规控制方法难以实现炉温预期的控制效果。针对此问题,提出一种基于改进型延时观测器的电热炉温度复合控制方法,将扰动观测器与延时观测器相结合,在消除系统集总扰动的同时,估计出时滞前的状态变量,简化滑模控制器的设计,提高系统的抗干扰能力,消除时滞危害。将所提控制方法与GPC控制、基于Smith预估器的模糊自适应PID控制进行仿真对比,结果表明：所提控制方案的响应速度更快,超调量几乎为零,抗干扰能力更强,鲁棒性更好。     

风电叶片部件疲劳试验机跟随控制策略研究

针对风电叶片部件疲劳试验过程中实际载荷与期望载荷跟随效果差的问题,提出一种超前自校正与改进线性自抗扰(LADRC)相结合的同步控制策略。该方法通过对实际载荷进行自校正补偿与系统误差以及外部扰动一起输入到改进线性自抗扰控制器,从而实现加载力和频率的有效控制。对疲劳试验机油电液伺服系统控制算法进行仿真分析,并通过搭建现场试验平台对同步控制策略进行有效性验证。仿真及试验结果表明：在较大载荷疲劳试验过程中,该控制策略显著提升系统的快速响应性和抗干扰能力,载荷误差控制在1%以内,相对于传统ADRC控制算法同步误差减小了56.14%,有效实现了风电叶片部件疲劳试验载荷的精确控制。     

动载诱发巷道底板冲击失稳机制及防控技术

针对巷道底板冲击地压的特点,基于材料力学理论与能量原理,建立了巷道底板冲击失稳力学模型,推导出了巷道底板发生冲击失稳的能量判据。通过数值模拟方法,分析了深埋巷道底板水平应力和弹性应变能密度演化规律,得出巷道底板水平应力是底板冲击主要诱发因素,且当巷道埋深一定时,动载强度越大,则水平应力对底板动压显现的控制作用越显著。基于理论与数值模拟分析结果,提出了深埋巷道底板大直径钻孔卸压方法,并进行了现场测试,结果表明大直径钻孔底板卸压有效地解除了底板冲击,保障了巷道安全高效掘进,可为类似矿井巷道底板冲击地压防治提供参考。     

带翼缘板圆形钢管顶进土体扰动规律研究

STS(Steel Tube Slab)管幕法以带翼缘板的圆形钢管密集顶进形成基本骨架,管间穿入连接螺栓并灌注混凝土。管间螺栓、翼缘板将各钢管连为一体,管幕横向刚度显著提高。带翼缘板的圆形钢管顶进引起的土体扰动更为强烈。本文基于弹性力学圆孔扩张理论,提出了带翼缘板圆形钢管的管周塑性区计算公式,进而得到适用于沈阳地层的土体扰动度半径的计算方法。通过静力触探原位试验,进一步研究了带翼缘板钢管管周边土体扰动影响程度。通过试验结果和理论计算进行对比分析,两者得到的扰动半径分别为1.51 m和1.32 m,吻合度较高。验证了本文提出管周塑性区计算公式的合理性。     

珠江三角洲地区竖向排水体施工扰动初探

竖向排水体施工具有挤土效应，按照平面应力问题，应用圆柱孔扩张理论分析表明，竖向排水体周围土体孔隙水压力显著增大，应力变化明显，形成瓶状塑性区。地面以下一定深度Zo范围内，塑性区半径取决于土体初始应力和不排水强度，并随深度增大；Zo以下，塑性区半径不再变化，其大小与土体初始应力、不排水强度，割线模量、排水体类型、间距、长度、导管类型等有关。施工扰动以塑性区为主，塑性区地面发生隆起，珠江三角洲地区，在饱和软粘土基中施工竖向排水体时，实测表明土体强度显著降低，最终沉降增大。计算表明扰动区半径可取塑性区半径的1.2倍，扰动区半径约为竖向排水体导管半径的9倍。     

取样扰动对土的工程性质指标影响的试验研究

本文报道了取样扰动对土的工程性质指标影响的一批研究成果。采用100mm和75mm两种直径的取土器取样作对比试验以研究取土器扰动的影响。试验证明取土器直径对试样的孔隙比、压缩系数、超固结比和天然强度等指标都有明显的影响。采用两种预固结处理的方法以恢复原生应力状态,用不固结不排水试验比较了应力状态对天然强度的影响。对取土过程中土体应变的分布及其对土样扰动的影响用有限元方法进行了模拟。     

The mechanical behaviour of weak mudstone (Opalinus Clay) at low stresses

Over the last 10 years argillaceous rocks (mudrocks), such as the Jurassic claystone Opalinus Clay, have gained acceptance as a potential host formation for geological disposal of nuclear waste. Observations from tunnels in Opalinus Clay at the Mont Terri rock laboratory, Switzerland, suggest that the excavation-induced response is not linear-elastic. The micro-structure of the Opalinus Clay has been identified as a source for this response. It has been demonstrated that diagenetic processes over the last 180 Ma have been responsible for the formation of strong diagenetic bonds locking latent strain energy into the micro-structure of Opalinus Clay. A conceptual model of the micro-structure, including the effects of diagenetic processes, has been developed as a framework to interpret the mechanical behaviour of the Opalinus Clay. Samples recovered at Mont Terri rock laboratory have been subjected to processes that have resulted in bond breakage and the release of locked-in latent strain energy. This tends to reduce the strength and deformation properties of samples and induces low stiffness non-linearity of the stress–strain curve at low stress levels. Numerical modelling of the sampling stress-path at Mont Terri rock laboratory shows that unloading was the dominant factor resulting in this response. As a result, samples can shed light on the unloading response of the rockmass to excavation. This non-linear behaviour has been quantified by means of routine laboratory compressive tests.     

盾构近距离穿越重大管线施工技术研究

在盾构法地铁隧道施工中，盾构近距离穿越重大管线是一个常见的现象．也是困扰施工单位的一个难题。文章结合工程实例，主要介绍盾构在近距离穿越地下管线时所采取的施工措施，为类似工程提供参考。     

大温差送风技术在高精度恒温空调中的应用可行性

为了研究空调大温差送风技术在高精度、多扰量恒温空调中应用的可行性,采用CFD数值模拟分析了恒温室不同送风温差下温度场和速度场的均匀性,研究了恒温室在不同送风温差下不同扰量作用时的温度动态响应特性。结果表明,空调送风大温差下的温度场和速度场以及温度稳定性能满足恒温室要求。