3D Digital Survey of Iron Tie-Rods in Masonry Buildings: Cross-Sections Analysis and Error Estimation

Ancient iron tie-rods are handcrafted elements with large geometric irregularities, due to production techniques (they are shaped by hammering and linked by hot-forging) and corrosion processes. In common practice, their cross section (that is one of the main parameter to assess their strength) is manually measured on site with a manual caliber. By analyzing a set of detailed three-dimensional (3D) digital surveys of real ancient tie-rods, this study provide an evaluation of the errors made by in-situ manual geometric measurements. In particular, it shows that, in some cases, manual on-site survey is sufficiently reliable and has errors that fall below 10%. Moreover, it shows that when tie-rods have high corrosion levels in hidden zones (typically those close or within the retaining walls) the on-site survey of visible parts only may produce far greater errors that exceed 100%, leading to a strong overestimation of the cross-section of the tie. The ongoing study is a first step toward the definition of correction coefficients to be applied to the on-site manual measurements of ancient tie-rods, with the final aim to improve the reliability of structural analyses.     

Dynamical Assessment of the Work Conditions of Reinforcement Tie-Rods in Historical Masonry Structures

Tie-rods are essential structural elements, which have been employed for centuries in masonry historical buildings, either during the construction or in successive strengthening interventions, with the aim of containing dangerous horizontal actions. The actual work conditions of these tie-rods, which are strongly influenced by their load history, are difficult to be quantified theoretically, and an effective method for their measure is of great importance in order to ensure the efficiency of these elements during the time and the stability of the entire building. Common measurements are often carried out adopting models based upon significant simplifications, like, for example, hinges at the extremities. These assumptions, rarely represent the real work conditions for anchorages. In this work, a non-destructive testing method is presented, based upon sophisticated dynamical models that can take into consideration many of the circumstances neglected by the simplified models. Four case studies are extensively described, trying to embrace the most common situations in term of peculiar features of the building, structural configuration, and load history. The discussion of the results yields the safety margin of the rod with respect to the material failure and provides important indications about the overall stability of the whole building.     

Disability Consciousness on the Frontlines of Urban Struggle

Drug wars, austerity and gentrification are interwoven social relations in many North American urban centres and are typically met with organising of varying degrees of militancy. Loïc Wacquant characterises many of these sites as highly stigmatised, associated with violence and pathology. In Toronto's downtown east end (DEE), one such stigmatised urban space, disabled activists are far from unfortunate casualties. They tend to refer to the DEE as an “urban battleground”, where disabled people politicise and challenge the DEE's pathology and stigma by linking into emerging radical disability politics across the global North and by developing localised revolutionary disability consciousness. Drawing on oral stories, zines and blogs of disabled activists and workers in Toronto's DEE, this article uses Rachel Gorman's dialectic of disability/disablement to analyse the emergence of revolutionary disability consciousness and the centrality of disabled people on the frontlines of anti‐gentrification and harm reduction organising in Toronto's DEE.     

先秦中国和古代希腊文明起源的地理环境之比较

文明起源的地理环境可以分为整体地理环境和中心地理环境。前者指文明整体能力所及的极限地理范围,后者指文明主体的主要活动区域。从这两个角度分别进行比较,将有助于解释希腊和中国文明侧重于陆地或是海洋发展的原因。     

论章士钊的调和史观

20世纪一二十年代,章士钊提出了调和史观。该历史观认为,“调和”是差异协同与对立统一,是宇宙运动的基本规律。正是社会各因素“调和”的作用,社会历史运动呈现承续性、渐变性、循环性的特点。从调和史观出发,章士钊主张人在社会政治生活中要做到宽容与妥协。     

让材料自己说话——浅论当前历史传记写作的一种趋势

《陈寅恪的最后二十年》、《顾颉刚和他的弟子们》、《束星北档案》等著作,代表了当前历史传记写作的一种趋势。《陈寅恪的最后二十年》的文本近似历史叙事散文;《顾颉刚和他的弟子们》的文本更接近史学论文;而《束星北档案》则类同电视记录片的文稿。这些著作共有的特点是:在修撰方式上,大量运用了第一手材料;在文本风格上,力求作品深入浅出、雅俗共赏;在写作理念上,坚持真实第一,尊重历史。这一趋势非常值得重视。     

关于利用历史文献信息进行环境演变研究的几点看法

针对如何更好地利用我国丰富的历史文献记录,开展历史时期环境演变研究,本文提出四点看法:从地球系统科学与全球变化研究的前沿中寻找研究的主题,在诸多不确定中寻找确定性答案,构建历史文献信息共享的环境演变研究平台,培养文理兼备的复合型人才。     

“采铜于山”与学术原创性思维

顾炎武以"采铜于山"的话,形象地说明了学术原创性的重要性.原创性的研究不只是要从原始史料上入手,从思想史研究上说,从原著、代表作入手,要站在一个时代的理论高度从根本上进行阐释,与此同时,也要看到学术与社会现实的关联.要注意到"述"与"作"的关联、"众手修书"与"成一家之言"的关联,还要注意到比次之业、考索之功与独断之学的关联.学者应有原创性研究的自觉意识,意识到这是关系到学术发展的大事.     

新时期我国法制建设的历史进程与基本经验

以1982年宪法的公布实施和1997年依法治国基本方略的确立为标志,新时期我国法制建设的历史进程可分为三个阶段:从1978年到1982年为恢复阶段;从1982年到1997年为全面发展阶段;1997年以来为全新发展阶段。新时期我国法制建设的基本经验主要有:必须正确处理党的领导与法制建设的关系;必须正确处理法制建设与经济建设的关系;必须把民主建设与法制建设结合起来;必须把立足中国国情与借鉴外国经验结合起来;必须不断完善法律监督体系。     

明清时期江淮西部地区干湿状况研究(1450-1911)

对明清江淮西部地区的旱涝史料进行梳理,对逐年州县旱涝灾害资料等级进行量化处理,并通过计算旱涝平均等级值和10年滑动平均值,重建1450—1911年该区域的干湿变化时间序列。结果发现,该区1450—1911年间共出现6个干湿阶段: 1450—1490年,以轻度干旱为主;1491—1545年,旱涝灾害频发,干湿波动较为明显;1546—1625年,旱涝灾害少发,干湿比较平稳;1626—1710年,以中度干旱为主,极端干旱事件发生频率显著增加;1711—1860年,气候湿润;1861—1911年,干湿波动偏湿润。不同的干湿阶段对江淮西部的湖泊也造成了一定的影响,干旱时期,湖盆积水减少,湖周萎缩;湿润时期,降雨增加,湖泊的蓄水量增加。