Applications of FBG-based sensors to ground stability monitoring

Over the past few decades, many optical fiber sensing techniques have been developed. Among these available sensing methods, optical fiber Bragg grating(FBG) is probably the most popular one. With its unique capabilities, FBG-based geotechnical sensors can be used as a sensor array for distributive(profile) measurements, deployed under water(submersible), for localized high resolution and/or differential measurements. The authors have developed a series of FBG-based transducers that include inclination, linear displacement and gauge/differential pore pressure sensors. Techniques that involve the field deployment of FBG inclination, extension and pore-pressure sensor arrays for automated slope stability and ground subsidence monitoring have been developed. The paper provides a background of FBG and the design concepts behind the FBG-based field monitoring sensors. Cases of field monitoring using the FBG sensor arrays are presented, and their practical implications are discussed.     

Change and Continuity:Chinese Villages in Transition (I)–Longmei Village

This is the first in a series of four articles ethnographically exploring instances of village transformation in peri-urban China.Each article presents an in-depth case study of a single village and its unique combination of change and continuity.Together,these case studies demonstrate the specificity and idiosyncrasy of village transformation and the need for planners to"take actions that suit local conditions"(yindi zhiyi).This first installment investigates Longmei Village in the Panyu District of Guangzhou Municipality.Longmei’s leaders have encouraged economic transformation through industrialization and real estate development while seeking to maintain the village’s socio-spatial continuity.These competing priorities have led to contradictions in Longmei’s development,as integration into economic networks brings new people,goods,and ideas to the village.This tension has intensified as both registered villagers and migrant workers have pursued divergent visions for Longmei’s future transformation.     

《鼠来宝4》

<正>剧情简介(Plot):Because of a series of misunderstandings~1,Alvin,Simon and Theodore come to believe that Dave is going to make a proposal~2 to his new girlfriend and then dump~3them.They have three days to get to him and stop the proposal,saving themselves not only from losing Dave but possibly from gaining a terrible stepbrother.由于一系列的误会,埃尔文、西蒙和西奥多开始有些相信戴夫打算向他的新女朋友求婚之后就抛弃他们。他们得在三天之内赶过去阻止这场求婚,这样不仅可以让他们不用失去戴夫,而且也可能避免多出一个可怕的同父异母的兄弟。     

Performance Evaluation of New Two Axes Tracking PV-Thermal Concentrator

The overall problem with PV （photovoltaic） systems is the high cost for the photovoltaic modules. This makes it interesting to concentrate irradiation on the PV-module, thereby reducing the PV area necessary for obtaining the same amount of output power. The tracking capability of two-axes tracking unit driving a new concentrating paraboloid for electric and heat production have been evaluated. The reflecting optics consisting of flat mirrors provides uniform illumination on the absorber which is a good indication for optimised electrical production due to series connection of solar cells. The calculated optical efficiency of the system indicates that about 80% of the incident beam radiation is transferred to the absorber. Simulations of generated electrical and thermal energy from the evaluated photovoltaic thermal （PV/T） collector show the potential of obtaining high total energy efficiency.     

壁骨系列家具

Recycled & Recyclable Made primarily with steel studs, the "Stud Series" TM is 100% recyclable and contains a high degree of recycled steel that would otherwise be destined for landfills. The series uses simple assembly techniques and a minimal number of materials to facilitate disassembly and recycling. the stud series TM life cycle     

Studies on the evolution process of rockbursts in deep tunnels

This paper focuses on the evolution processes of different types of rockbursts occurring in deep tunnels. A series of laboratory tests and in-situ monitoring in deep tunnels excavated by tunnel boring machine (TBM) and drill-and-blast (D&B) method have been conducted to understand the mechanisms and processes of the evolution of different types of rockbursts, including strain rockburst, strain-structure slip rockburst, immediate rockburst and time-delayed rockburst. Three different risk assessment methods are proposed to evaluate the intensity and potential failure depth of rockbursts. These methods can be applied before excavation and the results can be updated according to the real-time information during excavation. Two micro-seismicity based real-time warning systems have been established for predicting various intensities of rockbursts, such as slight, moderate, intensive and extremely intensive rockbursts. Meanwhile, the probability and intensity of the rockburst are also given. The strategy for excavation and support design has been suggested for various intensities of rockbursts before excavation. The strategy for dynamic control of the rockburst evolution process is also proposed according to the monitoring results. The methodology has been successfully applied to rockburst risk reduction for deep tunnels at Jinping II hydropower project. The results have illustrated the applicability of the proposed methodology and techniques concerning rockbursts.     

新目标英语七年级(上)Unit 5知识要点归纳

<正>【重点词组或短语】a tennis racket一个网球拍a soccer ball一个足球play soccer踢足球watch TV看电视play basketball打篮球sound great听起来很棒many sports clubs各种运动俱乐部play tennis打网球【重难点句子】1.—Do you have a ping-pong ball?——你有乒乓球吗?—Yes,I do./No,I don’t.——是的,我有。/不,我没有。2.—Does he have a tennis racket?——他有网球拍吗?     

Excavation-induced deep hard rock fracturing: Methodology and applications

To analyze and predict the mechanical behaviors of deep hard rocks,some key issues concerning rock fracturing mechanics for deep hard rock excavations are discussed.First,a series of apparatuses and methods have been developed to test the mechanical properties and fracturing behaviors of hard rocks under high true triaxial stress paths.Evolution mechanisms of stress-induced disasters in deep hard rock excavations,such as spalling,deep cracking,massive roof collapse,large deformation and rockbursts,have been recognized.The analytical theory for the fracturing process of hard rock masses,including the three-dimensional failure criterion,stress-induced mechanical model,fracturing degree index,energy release index and numerical method,has been established.The cracking-restraint method is developed for mitigating or controlling rock spalling,deep cracking and massive collapse of deep hard rocks.An energy-controlled method is also proposed for the prevention of rockbursts.Finally,two typical cases are used to illustrate the application of the proposed methodology in the Baihetan caverns and Bayu tunnels of China.     

Wind Force Coefficients for Designing Porous Canopy Roofs

Wind force coefficients for designing porous canopy roofs have been investigated based on a series of wind tunnel experiments. Gable, troughed and mono-sloped roofs were tested. The roof models were made of 0.5 mm thick perforated duralumin plates, the porosity of which was changed from 0 to about 0.4. Overall aerodynamic forces and moments acting on the roof model were measured in a turbulent boundary layer with a six-component force balance for various wind directions. The results indicate that the wind loads on canopy roofs generally decrease with an increase in porosity of the roof. Assuming that the roof is rigid and supported by the four corner columns with no walls, the axial forces induced in the columns are regarded as the most important load effect for discussing the design wind loads. Two loading patterns causing the maximum tension and compression in the columns are considered. Based on a combination of the lift and moment coefficients, the design wind force coefficients on the windward and leeward halves of the roof are presented for the two loading patterns as a function of the roof pitch and porosity. The effect of porosity is taken into account as a reduction factor of the wind loads.     

Probabilistic Seismic Hazard Assessment for Jamaica

A probabilistic seismic hazard analysis was performed to generate seismic hazard maps for Jamaica. The analysis was then conducted using a standard logic-tree approach that allowed systematically taking into account the model-based （i.e., epistemic） uncertainty and its influence on the computed ground motion parameters. Hazard computations have been performed using a grid of sites with a space of 0.05 degrees. Two different computation methodologies have been adopted： the standard approach based on the definition of appropriate seismogenic sources and the zone-free approach, which overcomes the ambiguities related with the definition of the seismic sources solely reflecting the characteristics of the earthquake catalogue. A comprehensive and updated earthquake catalogue for Jamaica has been compiled for the years 1551-2010 and new empirical relationships amongst magnitudes Mze-Ms and Mw-mb have been developed for the region. Uniform hazard spectra and their uncertainty have been calculated for the horizontal component of ground motion for rock site conditions and five return periods （95, 475, 975, 2,475 and 4,975 years） and spectral accelerations for 34 structural periods ranging from 0 to 3 s, and 5% of critical damping. The spectral accelerations have been calculated to allow the definition of seismic hazard in Jamaica according to the International Building Code 2012. The disaggregation analysis for Kingston Metropolitan Area suggests that the magnitude-distance pair that contributes most to the hazard corresponds to events with M 7.8 and M 7.0 in the Enriquillo Plantain Garden Fault and the Jamaican Faults at a distance of 28 km and 18 km for short and long period structures respectively corresponding to 2,475 years return period. However, for long period structures, a substantial contribution is found for a M 8.2 at a distance of 198 km in the Oriente Fault Zone.