Experimental and numerical study on compressive performance of perforated brick masonry after fire exposure

This paper discusses the compressive performance of perforated brick masonry after fire exposure. Compressive strength tests of the mortar, clay perforated brick, and perforated brick masonry specimens were performed in accordance with ISO834 fire tests of different durations. The temperature distribution of the masonry materials and specimens was simulated using the finite element software ABAQUS, with the thermal parameters of masonry materials recommended by European standard Eurocode 6 and related literature. The compressive strength reduction factors of mortar and clay perforated brick exposed to different fire durations were calculated via the layered method suggested by European standard Eurocode 1. In addition, the compressive strength reduction factors after cooldown were obtained from the experimental data of the masonry materials, and by considering further reductions in the compressive strength after cooling from high temperatures. Experimental data of the masonry specimens were compared with the numerical results obtained using the reduction factors proposed in this work. The comparison revealed an overall acceptable approximation. Thus, the method presented in this paper can be used to evaluate the residual capacity of masonry structures after fire.     

WAVE INTERACTION WITH PERFORATED CAISSON BREAKWATERS

The reflection coefficient of perforated caissons and the total horizontal forces acting on them were experimentally and numerically analyzed and discussed when wave propagates normally. To consider the viscosity effect of fluid and nonlinear action of waves on structures, the VOF (Volume Of Fluid) method combined with the k-ε turbulence model was used to simulate the interaction between waves and structures. Governing equations were solved with the finite difference method. Through 2D experimental study in the wave flume, the empirical relationship between the reflection coefficient of perforated caissons and the main affecting factors were obtained from the experimental data using the least square method. Also the correlation between the ratio of the total horizontal force acting on perforated caisson and the force acting on solid caisson and the main affecting factors were regressed from the experimental data.     

车古201潜山油藏完井方式研究

研究了国内外潜山油藏完井方式应用及其使用条件、井身结构的应用 ,针对车古 2 0 1油藏特点 ,论证了其对裸眼完井、筛管完井、尾管射孔完井、管外封隔器完井的适应性 ,通过对比研究 ,从更好地满足油藏工程、采油工艺、增产措施出发 ,选择出车古 2 0 1潜山油藏最合理的完井方式为尾管注水泥射孔完井 ,并给出了应采用的井身结构     

辅助消声器在轿车排气消声器性能研究中的应用

引入辅助消声器（BAM）原理，对T15汽车加速行驶产生的“噗噗”声进行试验分析，发现了原消声器系统存在的问题，并对原消声器结构做了优化，解决了“噗噗”声问题。     

降低冰箱噪声的试验研究

本文对一种冰箱匹配高效活塞式压缩机后噪声较大的问题进行了研究。这种噪声的峰值频率介于2 0 0～ 315Hz (1/ 3倍频程 )。本文确定了吸气管振动所形成的冰箱蒸发器的振动是产生噪声的根源 ,而吸气管的振动源为机壳的振动和气流脉动 ,并且气流脉动是主要激振力。在上述分析与试验的基础上 ,重新设计压缩机的吸气消音器 ,在吸气管壁钻孔 ,通过这些措施 ,使该冰箱的声功率降低了约 2dB (A) ,提高了冰箱的声质量     

铝合金穿孔板吸声墙面施工技术

以教育部综合办公楼工程的机房铝合金穿孔板吸声墙面施工为例,介绍其固定件及吸声墙面的做法。     

混凝土多孔砖应用技术研究

在分析了多孔砖力学特点的基础上,通过分析和研究,找出克服由于设计、施工原因造成的混凝土多孔砖砌体强度下降的措施。     

数据机房送风孔板处空气流动的数值模拟

以数据中心机房某一孔板及其相邻机柜为研究对象,采用ANSYS有限元分析方法,对孔板和机柜建立3种不同的有限元模型:几何实体模型、缩小送风孔板风口面积的基础模型、将孔板视为多孔介质面并添加源项的优化模型。根据实测数据确定3种模型的边界条件,通过有限元仿真计算获得它们的压力、速度云图,将基础模型和优化模型分别与几何实体模型进行对比。结果表明,优化模型与几何实体模型的速度场和压力场的大小误差在5%以内,同时优化模型的计算时间相较于几何实体模型可以减少60%。     

Alkaline peroxide generation using a novel perforated bipole trickle-bed electrochemical reactor

A novel perforated bipole trickle-bed electrochemical reactor is investigated for the electro-synthesis of alkaline peroxide. The process uses a relatively simple cell configuration in which a single electrolyte flows with oxygen gas in a flow-by graphite felt cathode, sandwiched between a micro-porous diaphragm and a perforated bipolar electrode plate. The graphite felt cathodes are 120 mm high by 25 mm wide and have a thickness of 3.2 mm. The reactor is operated at current densities in the range 1–5 kA m⁻², ca. 800 kPa (abs) pressure and temperature (In/Out) 20–45 °C with one and two-cells. The reactor shows good performance (current efficiency ∼78% at 2 kA m⁻² and a specific energy of 5 kWh per kg of peroxide generated) with peroxide concentrations from 0.02 to 0.15 M in 1 M NaOH.     

Changes in liquid hold-up in foam and size of foam by perforated plates and contribution to mechanical foam-breaking

Changes in the liquid hold-up, ?, and the diameter of d, of a foam that are induced by perforated plates (PPs) and the contribution of PPs to foam-breaking were studied. A foaming system containing a dilute detergent solution in a column with mechanical agitation fitted with a rotating-disk foam-breaker (MFRD) was used. After the foam passed through the PPs, ? and d decreased and increased, respectively. The use of PPs to achieve a maximum reduction in ? and a maximum increase in d is confirmed. It is also demonstrated that use of PPs contributes not only to improving the foam-breaking performance of the MFRD, but also to power savings.