First-mode properties of N-story buildings

First-mode properties of $\text{N-}\text{story}$ buildings determined from a standard computer program possess certain simple relationships which can be displayed graphically by straight lines. Structures investigated include uniform buildings and buildings with reduced first floor stiffness. Some of the results presented are verified analytically from difference equations.     

Analytical model method for dynamics of N-celled tetrahedron–tetrahedron variable geometry truss manipulators

In this paper some fundamental formulae are derived for a tetrahedron-based variable geometry truss manipulator which is composed of a series of tetrahedrons stacked upon each other such that one link in each cell is made variable in length. Analytical model for dynamics of the manipulator is established, and expressions in numeric–symbolic form of model matrices are derived. An example is given for illustration.     

A techno-economic sizing method for PV/battery/grid hybrid solar systems for residential buildings

Journal of Mechanical Science and Technology - The increasing share of the distributed renewable energy in power generation is an important development direction in the electrical power system....     

Tribological properties of epoxy/rubber nanocomposites

The effect of nanorubber particles on the tribological properties of epoxy was investigated under dry sliding friction and different applied loads. The microhardness, morphologies and chemical compositions of the surfaces of epoxy resin and its nanocomposites before and after wear were analyzed. The results reveal the influence of the nanorubber particle content on the wear resistance and friction coefficients of the nanocomposites. The 5 wt% content of the nanorubber particles is the most effective in reducing the wear mass loss and friction coefficient of the nanocomposites. With further increase in the content of the nanorubber particles, the nanorubber particles agglomerated, and the hardness of the nanocomposites decreased, which resulted in the increase of the specific wear rate.     

一种高楼救生器的设计

设计了一种自发电的高空缓降救生器,该救生器具有体积小、重量轻、负载大、救援高度可达100m、安装方便等优点.其工作原理是利用多级齿轮实现增速传动,将人体下降时的速度传递给发电机并带动发电机转动发出电能,并通过功率热电阻转化成热能耗散,减少势能向动能的转化,从而实现高空缓降.根据人体正常重量,确定采用三级增速齿轮实现速度传递,设计计算了各级齿轮传动比,并利用Pro/E软件完成救生器的三维模型设计.该救生器可广泛应用在高层楼房等环境下发生火灾时的高空缓降逃生.     

MoS2对镍基复合材料力学性能的影响

用粉末冶金热压制备了含不同MoS2质量分数的镍基复合材料,发现MoS2的加入可增加材料的硬度,却降低了抗弯强度,光学电镜和X射线衍射分析组织及物相表明,材料的力学性能与形成的碳化物和硫铬化合物有关.     

Consumer load measurement in automated buildings

Diminishing fossil fuel supplies accompanied by rising prices is increasingly leading to consumer awareness regarding their energy consumption. With the intent to prepare for diminishing primary energy sources, sustainable alternatives (e.g. energy gained through wind or solar power and trends towards smart grids) have been introduced and found wide application. With the application of intelligent solutions, the energy consumption in buildings can be reduced significantly. One basis for these solutions, such as load and energy management for optimized energy distribution and saving, is the energy metering of components in electric systems. This contribution shall present a field bus system that, due to its local distribution and system architecture, is suitable for energy consumption measurement of its individual components. After presenting the SmallCAN bus system and its concept, a summary of the mathematic algorithm and an example application will be shown to exemplify the functionality.     

System identification of smart buildings under ambient excitations

This paper proposes a nonlinear autoregressive moving average (NARMA) model for use in system identification (SI) of high performance smart buildings under ambient excitations. The NARMA model is implemented by including the cross terms of output signals to a linear autoregressive moving average (LARMA) time series model. To demonstrate the effectiveness of the proposed NARMA approach, a three-story building equipped with smart control devices is investigated under a variety of ambient excitations. To access the robustness of the proposed model, it is tested under various levels of measurement noises. It is demonstrated from the extensive simulations that the proposed NARMA model is effective in predicting the ambient vibration responses of the high performance smart buildings with severe measurement noises.     

Sliding friction and wear properties of CNX/TiN composite films

A combined dc magnetron sputtering and multi-arc deposition system was used to grow CN_X/TiN composite films on a high-speed-steel (HSS) substrate. The thickness of these films is about 3 μm, the hardness of the coating exceeds 50 GPa. The sliding friction properties were studied by ball-on-disc tests under different loads and speeds. The wear mode of the films was observed and analyzed. There exist spallation, abrasion and micro-ploughing wear modes under different loads. The critical load value was theoretically determined and tested to be 55 N. The results show that the alternating films have good wear resistance under heavy load and high speed.     

高层建筑节能供水系统

介绍了一种利用PLC技术，达到高效节能的高层建筑供水设备。     

Mechanical properties of bio-absorbable PLA/PGA fiber-reinforced composites

This study investigated important mechanical properties, the flexural strength and flexural modulus, of polyglycolic acid (PGA) fiber-reinforced polylactic acid (PLA) composites fabricated by melt-mixing. The flexural strength and flexural modulus were estimated using three-point bending tests conducted at 37°C. Both the flexural strength and flexural modulus were increased by PGA fiber reinforcement. Viscoelastic properties were also investigated using dynamic mechanical analysis (DMA) under tensile loading. Results show that PGA fiber, which acts as the nucleate agent of PLA, restrains the molecular chains of PLA. That restraint reduces deformation at the same stress condition, thereby improving the PLA flexural properties.     

Tribological properties of carbon nanotube-doped carbon/carbon composites

Carbon nanotube (CNT)-doped carbon/carbon (C/C) composites were fabricated by the chemical vapor infiltration (CVI) method to investigate the effect of CNTs on tribological properties of C/C composites. CNTs, which had been synthesized by catalytic pyrolysis of hydrocarbons, were added to carbon fiber formed preforms before CVI process. Ring-on-block-type wear tests were performed to evaluate the frictional properties of CNT-doped C/C composites. Results show that CNTs can not only increase wear resistance of C/C composites but also maintain stable friction coefficients under different loads. Polarized light microscopy, X-ray diffraction, scanning electron microscopy and Raman spectroscopy analyses demonstrate that favorable effects of CNTs on tribological properties of C/C composites have been achieved indirectly by altering microstructure of pyrocarbons and directly by serving as high-strength lubricative frictional media at the same time. Electron dispersive spectroscopy (EDS) analyses verify the existence of adhesive wear mechanism in both pure C/C composites and CNT-doped C/C composites albeit the two-body abrasive mechanism dominates in pure C/C composites.     

CRT微机显示系统在智能建筑中的应用

阐述CRT图形显示系统在智能建筑领域中的功能及应用。     

建筑物内WLAN远程无障碍通讯技术研究

本文分析广播式无线局域网(WLAN)室内通讯数据丢包、信号盲点和连接不上等问题与微波多路径传播延迟间的关系,以及波的干涉效应,认为双镜面反射形成的波导效应对室内通讯造成严重影响,障碍物造成波前畸变.这影响了网络化仪器的可靠性及其在现场测试中的应用.提出用指向性好的定向天线,并利用狭长走廊空间远距离传输电磁波.用2个相反指向的天线可获得传播线度140m以上.引入角反射器将信号导入远端室内,以克服微波屏障问题.角反射器的投影尺寸须大于波长λ.针对发生在路由器接收端上的大量丢包,提高无线网卡定向发射能力和增益更换网卡天线,用λ天线代替λ/2天线抑制垂直波面宽度,将全向天线增加反射面改造成定向天线.模拟计算120°反射面在20°前向辐射角的情况下,增益8.4dB.选用500mW发射功率的路由器可提高室内远程通讯能力近1倍.走廊末端墙面修饰成多棱角,可降低垂直入射的反射波.本技术可用于运动部件无线测量和智能仪器现场组网等场合.     

Morphological properties of sputtered MoS2 films

As the lubricating properties of MoS₂ are due to the sliding of lamellae, the crystallographic orientation and structural properties of these lamellae are important for the tribological behaviour. Thus an analysis of the growth morphology of sputtered MoS₂ films was carried out. It is shown that morphological properties can be influenced by the parameters of the deposition process; in particular, it is possible to prepare coatings in which the lamellae are oriented parallel to each other.     

现有多层住宅加装电梯的可行性分析

最近资料表明，我国人口老龄化现象已十分明显，而且随着时间的推移还将更加突出。而到2050年，我国目前所建立的住宅尚在服役期，在无电梯的六、七层楼层中居住的老年人将为数不少，他们迫切希望能在住宅里得到便捷的垂直交通。因此，专家认为，对多层住宅电梯产品的需求将会稳步增长。本文着重探讨已有多层住宅加装电梯的结构方案和驱动方式的选择。     

基于GPRS和CAN的楼宇照明监控系统

针对目前楼宇智能化的发展需求,提出了一种结合嵌入式技术、GPRS无线通信技术和CAN总线技术的楼宇照明监控系统的设计方案.详细地描述了该系统终端的数据采集、底层数据传输、无线通信的实现过程;同时针对系统中多种通信方式结合的情况,研究了具体通信协议的制定问题;最后对系统的整体稳定性和通信的准确性进行了测试.测试结果表明:通过GPRS与CAN总线相结合的方式,该监控系统能够有效地完成系统的网络化,并最终实现了对楼宇照明设备的远程监控.     

Neuro-fuzzy techniques for the classification of earthquake damages in buildings

The identification of damages produced by severe earthquakes on constructions is important for several reasons such as public safety, economical recourses management, infrastructure and urban planning. After the manifestation of an earthquake, engineers have to evaluate the safety of existing structures and decide the actions to be taken. In this study two techniques are proposed for automatic damage classification in buildings. The inherent information contained in accelerograms is described by 20 seismic parameters. Two classification models of earthquake damages based on artificial neural networks and neuro-fuzzy systems were designed. Furthermore, they were tested for their effectiveness to classify structural, architectural, mechanical–electrical-plumbing and contents damages. The proposed systems were trained and tested with three reinforced concrete frame structures. Results show correct classification rates up to 98%. According to these classification rates these techniques are proven a suitable tool for classification of earthquake damages in structures.