Modelling and Seismic Response Analysis of Italian Code-Conforming Base-Isolated Buildings

ABSTRACT

This paper reports on results of nonlinear analyses performed within the RINTC project on an RC building isolated with different systems (High Damping Rubber Bearings, High Damping Rubber Bearings and Flat Sliding Bearings, Friction Pendulum System) and designed according to the Italian design code. The seismic response has been evaluated under different seismic input levels of two sites with different hazard and by considering two Limit States: Global Collapse and Usability-Preventing Damage. The influence of seismic stoppers and modelling uncertainties is also evaluated. Results permit to compute the implicit collapse risk and to identify critical aspects of current design procedures.     

Performing a different narrative: museum theater and the memory-work of producing and managing slavery heritage at southern plantation museums

In the southeastern United States, operators of plantation museums have traditionally engaged in a selective and romanticised remembrance of the antebellum past that has regrettably silenced and marginalised the historical experiences and struggles of enslaved African people. More recently, some plantation managers have sought to engage in the ‘memory-work’ using artistic practices to reconstruct and interpret slavery heritage for visitors. Our study explores museum theatre as a form of memory-work and suggests that theatrical performances of the memories of enslavement are an increasingly important but not yet fully understood strategy for recovering, embodying, and representing a different and hopefully more just narrative about enslaved Africans. We visit three plantation museums where managers hosted a theatrical performance of enslaved oral histories and explore the motivations and experiences of managers and the director of the slave performance. Realising the power and efficacy of theatrical performance as memory-work practice requires understanding how the management of the interpretation process can be difficult. We delve into the emotion-laden challenges confronting slavery-related museum theatre development at the North Carolina plantations and discuss the creative response formulated at the sites to help visitors work through unexpected feelings and understandings about the past.     

大米换橡胶：20世纪50年代的中锡贸易

1952年9月和12月,中国与锡兰从各自的需要出发,签订了以大米换橡胶为主要内容的政府贸易协定,不仅开创了新中国同尚未建交、又是不同社会制度国家签订政府贸易协定的先河,而且建立了新中国与锡兰间的贸易关系,促进了两国贸易额的迅速增长。1957年8月,中锡在签订第二个五年贸易协定时,面对超价难题,周恩来提出了将贸易和援助分开来谈,即橡胶贸易按照公平的市场价格,但中国同时给予锡兰经济援助的设想,使谈判进入了比较顺利的阶段。中锡贸易协定的执行和续订,从南亚和东南亚方向打开了美国对华封锁、禁运的缺口,促进了中锡友好关系的发展。     

美国内战前种植园奴隶主与黑人奴隶的关系

压迫与反抗无疑是奴隶制的重要特征。然而,美国黑人奴隶制之所以能够维系二百余年,其重要原因在于奴隶主和奴隶都在不断地调整彼此相处的策略。所以,美国内战前南部种植园中奴隶主与奴隶之间形成了一种既相互对立又相互妥协的关系。     

陈云与新中国的橡胶事业

建国初期,为落实中共中央的战略决策,陈云通过调查和实地考察,对如何发展橡胶事业,提出和实施了一系列重大措施:建立橡胶基地,组建橡胶垦殖队伍,解决橡胶种子问题,适时调整橡胶事业的失误。陈云关于橡胶事业的一系列重要指示和意见,对于搞好我国的橡胶事业,不仅起到了巨大的推动作用,而且也有着重大的现实意义。     

Rubber plantations and their implications on gender roles and relations in northern uplands Vietnam

Abstract

In recent years, rubber plantations have been strongly promoted in the northern uplands of Vietnam–especially in the northwest, where it is an ill agro-ecological fit–with an aim to improve ethnic minority livelihoods and to modernize peasants by transforming them into rubber workers. A large area of land has been taken away from farmers to make way for rubber plantations. This land acquisition and agrarian transformation have impacted local people and their livelihoods in various ways. Drawing on ethnographic research, in combination with interviews with authorities and studying related documents, this article focuses on the gendered consequences of rubber plantation in northern uplands Vietnam. It argues that the process of becoming a rubber worker and adapting to the new way of living has indeed added new roles and responsibilities for women. At the same time, it has undermined men’s values and reshaped gender relations both within and outside the home.     

French-Caribbean Refugees and Slavery in German Protestant Maryland

The late eighteenth century saw the immigration of thousands of French refugees from France and its Caribbean colonies to the United States. An examination of one family of these refugees, Jean Payen de Boisneuf and his relatives the Vincendières, reveals that the values that the refugees imported, such as plantation slavery and Catholicism, could be antagonistic to social norms in the regions they chose to settle.     

INTEGRATED PASSIVE-ACTIVE SYSTEM FOR SEISMIC PROTECTION OF A CABLE-STAYED BRIDGE

This paper presents an integrated passive-active (i.e. hybrid) system for seismic response control of a cable-stayed bridge. Since multiple control devices are operating, a hybrid control system could alleviate some of the restrictions and limitations that exist when each system is acting alone. Lead rubber bearings are used as passive control devices to reduce the earthquake-induced forces in the bridge and hydraulic actuators are used as active control devices to further reduce the bridge responses, especially deck displacements. In the proposed hybrid control system, a linear quadratic Gaussian control algorithm is adopted as a primary controller. In addition, a secondary bang-bang type (i.e. on-off type) controller according to the responses of lead rubber bearings is considered to increase the controller robustness. Numerical simulation results show that control performances of the integrated passive-active control system are superior to those of the passive control system and are slightly better than those of the fully active control system. Furthermore, it is verified that the hybrid control system with a bang-bang type controller is more robust for stiffness perturbation than the active controller with a μ-synthesis method, and there are no signs of instability in the over-all system whereas the active control system with linear quadratic Gaussian algorithm shows instabilities in the perturbed system. Therefore, the proposed hybrid protective system could effectively be used for seismically excited cable-stayed bridges.     

杭州文庙彩绘现场保护研究

杭州文庙彩绘被清漆层覆盖,1988年涂覆的清漆已有发黄、鼓泡等老化现象。本文通过老化试验说明清漆已经进入了全面老化期,并且描述清漆老化对彩绘安全的危害。对彩绘颜料和清漆进行了取样分析,经过EDS检测,证明颜料主要成分是无机矿物。经过红外分析,证明清漆主要成分是多羟基丙烯酸聚合物。在文物保护现场,通过研究清漆老化程度和光照度之间的关系,证明光照是清漆老化的重要原因。在实验室研究出去除清漆而不伤及彩绘的溶胀剂,在现场通过测试色差和光泽度数值的变化,证明溶胀剂去除清漆的有效性。彩绘封护剂采用有机氟橡胶,通过接触角和耐湿热试验,证明有机氟橡胶具有较好的憎水性和耐湿热老化能力。同时在现场,通过彩绘保护前后的色差和光泽度变化,说明经过机氟橡胶保护处理过的彩绘,外观没有明显的变化。     

乡村旅游对农户农林业生产和外出务工影响研究——基于陕西22个旅游扶贫村农户调查数据

利用课题组2017年6-8月在陕西安康、商洛、汉中、宝鸡4市9县22个旅游扶贫村收集的841个农户调查数据，采用双重选择模型（DSM）等分析了农户参与旅游对家庭农林业劳动时间、外出务工时间的影响。研究发现，参与旅游有助于增加调查地的农户收入，旅游兼营型农户收入更高。在全样本中，参与旅游对农户农林业生产时间具有显著负向作用，但在参与了旅游的农户样本中，农户参与旅游一些特征或形式，如土特产销售，对农林业生产则有显著正向作用；在多个模型中，农户从事旅游对家庭外出务工活动具有显著的负向作用。提出了延长农业产业链、发展“旅游+农业”、促进农村一二三产业融合，提高景区带村作用、完善旅游扶贫政策等对策建议。