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1.
Structural vibration control using active or passive control strategy is a viable technology for enhancing structural functionality and safety against natural hazards such as strong earthquakes and high wind gusts. Both the active and passive control systems have their limitations. The passive control system has limited capability to control the structural response whereas the active control system depends on external power. The power requirement for active control of civil engineering structures is usually quite high. Thus, a hybrid control system is a viable solution to alleviate some of the limitations. In this paper a multi‐objective optimal design of a hybrid control system for seismically excited building structures has been proposed. A tuned mass damper (TMD) and an active mass driver (AMD) have been used as the passive and active control components of the hybrid control system, respectively. A fuzzy logic controller (FLC) has been used to drive the AMD as the FLC has inherent robustness and ability to handle the non‐linearities and uncertainties. The genetic algorithm has been used for the optimization of the control system. Peak acceleration and displacement responses non‐dimensionalized with respect to the uncontrolled peak acceleration and displacement responses, respectively, have been used as the two objectives of the multi‐objective optimization problem. The proposed design approach for an optimum hybrid mass damper (HMD) system, driven by FLC has been demonstrated with the help of a numerical example. It is shown that the optimum values of the design parameters of the hybrid control system can be determined without specifying the modes to be controlled. The proposed FLC driven HMD has been found to be very effective for vibration control of seismically excited buildings in comparison with the available results for the same example structure but with a different optimal absorber. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
2.
结构振动控制的半主动磁流变质量驱动器(MR-AMD) 总被引：14，自引：1，他引：14
本文首先提出了一种新型的半主动磁流变质量驱动器（MR－AMD），该装置用磁流变驱动器替代AMD的液压驱动系统；其次采用所提出的半主动控制算法仿真分析了MR－AMD用于结构振动控制的有效性；第三，比较了半主动质量驱动器（MR－AMD）、调谐质量阻尼器（TMD）及主动质量驱动器（AMD）对同一模型结构的控制效果。分析结果表明，MR－AMD作为一种半主动质量驱动器有效地降低了结构的反应，其控制效果虽然不如具有相同质量块参数的AMD但却优于TMD，且同AMD一样具有较宽的有效频带范围。 相似文献
3.
海洋平台结构振动的AMD主动控制参数优化分析 总被引：5，自引：0，他引：5
本文针对海洋平台结构的冰激振动和地震反应控制问题，提出了采用AMD主动控制的控制策略，结合JZ20－2MUQ平台结构进行了AMD控制系统的硬参数和软参数的优化分析，并就相应于最优参数下的AMD控制海洋平台结构冰激振动和地震反应的几种代表性工况进行了时程分析，得到了一些定性和定量的结论，为实际工程的控制设计提供了基础。本文提出的AMD主动控制方法对类似的海洋平台结构的控制问题也有参考价值。 相似文献
4.
Mine-drainage water from coal mines of Kerman region,Iran 总被引：1，自引：0，他引：1
Two types of mine-drainage water were recognized in Kerman coalfield, namely neutral to alkaline and acid (AMD). Both types contain a high level of trace-metal concentrations with a higher level in AMD. Trace metals from the coal-mine waters of Kerman coalfield are mainly present as adsorption on Fe and Mn oxide and hydroxide particles, and to a lesser extent as sulfate, simple metal ions and as metal sorption on clay particles and hydrous aluminum oxides. 相似文献
5.
6.
The Stockton Coal Mine, located on the West Coast of New Zealand, is evaluating the use of a mussel shell bioreactor (MSB) to treat acidic metalliferous runoff from acid forming overburden. This novel approach is similar in concept to vertical flow wetlands (VFWs) and successive alkalinity producing systems (SAPS). The MSB system is a trapezoidal pit 2 m deep, 35 m long, 3–10 m wide with 60° angle sides. During operation it contained 160 tonnes (240 m3) of mussel shell material and was saturated with a 100–200 mm water cap. Influent flowed through the reactor at a mean rate of 0.3 L s−1 resulting in a hydraulic retention time (HRT) of ≈6 days. The prototype MSB was in operation for a total of 1027 days, from June 2009 through March 2012, and effectively sequestered 99.7% of Al, 99.3% of Fe, 98.8% of Ni, 98.4% Tl and 99.3% of Zn, as determined from a previous evaluation of MSB performance. The MSB also effectively neutralized acidity, which resulted in an increase in influent pH from 2.8 to 6.9 in the effluent. Based on an examination of several excavated pits, five distinct reaction zones developed within the MSB. The reaction zones consisted of an allochthonous sediment layer (0–330 mm), an oxidized iron-rich ocherous layer (at 330–350 mm depth), an aluminum layer (at 350–600 mm depth) with geochemical variations throughout (350–500 mm and 500–600 mm); and a chemically reduced bottom shell layer (at 600–1100 mm). Representative samples were collected from each layer and analyzed using a combination of geochemical and physical methods to assess the stability of the secondary minerals and trace metal deportment within the MSB. Major elements Fe, Al, Ni, Tl, and Zn where preferentially associated with particular layers within the MSB. Elevated concentrations of Fe (110,000 mg kg−1) were observed in the allochthonous sediment and ocherous precipitate layers, while Al (27,816 mg kg−1), Ni (55 mg kg−1), and Zn (655 mg kg−1) were elevated within the aluminum and lower reduced depths within the MSB. Trace Tl (21 mg kg−1) showed varying concentrations throughout the MSB, but was strongly correlated to lower layers of the system. Microbial biofilms were observed within the reduced portions of the shell layers often proximal to bacterial shaped sulfides. The geochemical assessment of the MSB presented in this study is the first of its kind for a MSB, and supports the argument that this system is another viable option for passive treatment of AMD. 相似文献
7.
控制系统与结构振动的相互作用(Control Structure Interaction,简称CSI)广泛存在于结构与主动控制系统之间,然而目前在直线电机驱动的塔系结构风振控制研究中往往没有充分考虑CSI效应,使得理论控制效果与实际控制效果存在偏差。为了考察CSI效应对塔系结构风振控制的影响,首先以电磁驱动AMD系统"电-力-运动"相互关系模型为基础,建立考虑CSI效应的塔系结构直线电机驱动AMD风振控制系统模型;其次综合权衡计算效率和控制精度的关系,选取考虑低阶CSI效应模型以及最经典的LQR控制算法。在此基础上,对该塔系结构确定是否考虑CSI效应进行相应的控制分析。结果表明,CSI效应在塔系结构风振控制中起着重要的作用,制定与实际工程结合更佳的直线电机驱动AMD系统风振控制方案中需要考虑CSI效应,为以后在实际工程中推广应用提供一种新思路。 相似文献
8.
Pan Wu Changyuan Tang Congqiang Liu Lijun Zhu TingQuan Pei Lijuan Feng 《Environmental Geology》2009,57(7):1457-1467
The chemical characteristics, formation and natural attenuation of pollutants in the coal acid mine drainage (AMD) at Xingren
coalfield, Southwest China, are discussed in this paper based on the results of a geochemical investigation as well as geological
and hydrogeological background information. The chemical composition of the AMD is controlled by the dissolution of sulfide
minerals in the coal seam, the initial composition of the groundwater and the water–rock interaction. The AMD is characterized
by high sulfate concentrations, high levels of dissolved metals (Fe, Al, Mn, etc.) and low pH values. Ca2+ and SO4
2− are the dominant cation and anion in the AMD, respectively, while Ca2+ and HCO3
− are present at significant levels in background water and surface water after the drainage leaves the mine site. The pH and
alkalinity increase asymptotically with the distance along the flow path, while concentrations of sulfate, ferrous iron, aluminum
and manganese are typically controlled by the deposition of secondary minerals. Low concentrations of As and other pollutants
in the surface waters of the Xingren coalfield could be due to relatively low quantities being released from coal seams, to
adsorption and coprecipitation on secondary minerals in stream sediments, and to dilution by unpolluted surface recharge.
Although As is not the most serious water quality problem in the Xingren region at present, it is still a potential environmental
problem.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
9.
结构参数非匹配不确定性问题的滑动模态控制 总被引：1，自引：0，他引：1
本文针对结构参数非匹配不确定性问题,采用简化滑动模态控制方法．即在滑动面的没计中忽略非匹配不确定性的影响,对一个顶层放置AMD系统的五层弹塑性建筑结构进行了主动控制数值分析．考虑了结构层屈服位移的不确定,数值模拟结果表明,简化方法具有很强的鲁棒性,结构参数相对于期望值的变化幅度为-40％至40%时．简化方法均有很好的控制效果。 相似文献
10.
Light-induced reduction of dissolved and particulate Fe(III) has been observed to occur in the surface waters of the acidic
mine pit lake of San Telmo (143,600 m2, pH 2.8, Fetotal = 2.72 mM). This photochemical production of Fe(II) is directly related to the intensity of solar radiation and competes
with biologically catalyzed reactions (i.e., bacterial re-oxidation of Fe(II)) and physical processes (including ionic diffusion,
advection, and convection, which tend to homogenize the epilimnetic concentration of Fe(II) at every moment). Therefore, diel
cycles of Fe(II) concentration are observed at the lake surface, with minimum values of 10–20 μM Fe(II) (0.35–0.70% Fetotal) at the sunrise and sunset, and maximum values of 90 μM Fe(II) (3.2% Fetotal) at midday in August 2005. Field and experimental work conducted in San Telmo and other pit lakes of the Iberian Pyrite Belt
(IPB) (pH 2.3–3.1, Fetotal = 0.34–17 mM) indicate that the kinetics of the photoreductive reaction is zero-order and is independent of the Fe(III) concentration,
but highly dependent on the intensity of solar radiation and temperature. Experimental work conducted with natural Fe(III)
minerals (schwertmannite, goethite, and lepidocrocite) suggests that dissolved organic matter is an important factor contributing
to the photochemical production of Fe(II). The wavelengths involved in the photoreduction of Fe(III) include not only the
spectrum of UV-A radiation (315–400 nm), but also part of the photosynthetically active radiation (PAR, 400–700 nm). This
finding is of prime importance for the understanding of the photoreduction processes in the pit lakes of the IPB, because
the photo-reactive depth is not limited to the penetration depth of UV-A radiation (upper 1–10 cm of the water column depending
on the TDS content), but it is approximately equal to the penetration depth of PAR (e.g., first 4–6 m of the water column
in San Telmo on July 2007); thus, increasing the importance of photochemical processes in the hydro(bio)geochemistry of pit
lakes. 相似文献