Identification of Suitable Limit States from Nonlinear Dynamic Analyses of Masonry Structures

Performance-based earthquake engineering, developed over the last decades for the design and assessment of other structures, can also be applied for masonry structures if the particularities of masonry are incorporated into the procedure. According to this methodology, structural performance can be assessed according to damage states which are identified through displacement/damage indicators. While various methods for the identification of limit states from the results of nonlinear static analyses exist, the identification of damage states from the results of nonlinear dynamic analyses is still uncertain. This article investigates a number of criteria allowing to identify the attainment of significant limit states from the results of time history analyses, in terms of appropriately identified response quantities. These criteria are applied to five building prototypes and their results are compared. A comparison with the limit states derived from nonlinear static analyses is also made.     

Reduction Factors for Seismic Design Spectra for Structures with Viscous Energy Dampers

A simple mathematical expression is proposed to estimate spectra reduction damping factors for seismic design of systems with viscous dampers. The expression is obtained from the ratios between ordinates of uniform hazard spectra associated with two different return intervals (50 and 125 years), corresponding to sites with different types of soil within the Valley of Mexico. The expression proposed depends on the dominant period of the soil, and on both the vibration period and damping ratio of the structural system. Values of the damping factors proposed here are comparable to those recommended by different authors and seismic design building codes.     

“The white hands ‘damn them … won't stick’”: labor scarcity and spatial discipline in the antebellum iron industry

This essay seeks to broaden the empirical basis for the concept of spatial discipline by investigating how and why the geographical mobility of skilled iron workers was constrained in the United States during the decades preceding the Civil War. Drawing on neo-Marxist labor theory, the author finds that the paradoxical demands of industrial capitalism for a highly mobile labor force that would also stay in place created particularly acute tensions in the iron industry, where skilled labor was critical to the implementation of new technologies. Recent theoretical developments in legal and labor history help explain why the transition from master-and-servant relations to employment at will in the early nineteenth century heightened tensions in the iron industry and spawned a tremendous range of disciplinary strategies. After modeling managerial strategies as a continuum of coercion, the author presents a series of illustrative examples from the North and South.     

Marine trophic levels targeted between AD 300 and 1500 on the Georgia coast,USA

The marine trophic levels targeted during Swift Creek (AD 300–700) and Savannah (AD 1200–1500) occupations at the Cathead Creek site (9Mc360) and at two sites from the Kings Bay Locality (9CAM171a, 9CAM177), coastal Georgia, USA, differ in a consistent temporal and spatial pattern. Vertebrate and invertebrate remains from these three coastal sites contain similar suites of estuarine animals. However, Swift Creek peoples at these distinct hydrological settings obtained more biomass from fishes and less from molluscs compared to the subsequent Savannah occupants. The two Swift Creek faunal collections are less rich, more diverse, and more equitable than the two subsequent Savannah collections regardless of location. Furthermore, the mean trophic level is higher in the Swift Creek collections compared to the Savannah ones at both locations. These observations apply to both biomass and Minimum Number of Individuals. These differences likely are defining characteristics distinguishing the Swift Creek and the Savannah economies. More research is needed to determine the extent to which these temporal and spatial patterns are attributable to environmental and cultural variables.     

An inquiry into the causes for the multiple goals of the United States Antitrust Law from a historical perspective

It is not the case as Robert Bork claims that the U. S. antitrust law had only one goal—maximization of consumer welfare of efficiency—at the very beginning and should have been kept that way for its later development. Partly because of the fighting among different interest groups as well as spokesmen of different regions at the 51st Congress, the Sherman Antitrust Act came out as a legislation with multiple goals, which were also taking shape under the influence of the Republican idea of balance of power, the liberal belief in property rights, the freedom of contract of classic economics, and the price theory of neoclassic economics. In more than a hundred years after that, the U.S. antitrust law has shifted the center of its goals as a result of the change of regulatory regimes with different emphases such as market function, economic stabilization, social concern, and economic efficiency during different periods. From a historical perspective, it is beyond dispute that the U.S. antitrust law has had multiple goals instead of only one. __________ Translated from: Shixue Yuekan 史学月刊 (Journal of Historical Science), No.6, 2004     

19世纪末至20世纪20年代美国外交思想探析

从19世纪末叶以来,美国外交思想经历了从孤立主义向所谓的“国际主义”的转变,这种转变到了第一次世界大战爆发后基本完成,其核心内容是美国借助着强大的经济、军事和化力量,大踏步地迈向国际政治竞技场,实现这一时期绝大多数美国领导人梦寐以求的世界领袖地位。然而,这种转变在国内外遇到了强大的阻力,最终把美国的世界领袖梦想化为烟云。不过,美国的政治、经济和战略等利益已经使美国无可解脱地与世界联系在一起。就美国外交而言,这是一个不可逆转的趋势,美国人厌恶卷入大洋之外政治事务的传统心态由此正发生着变化,这也预示着美国力图充任世界领袖的时代正在缓慢地到来。     

20世纪美国联邦政府行政改革的历史考察

美国联邦政府的行政改革贯穿于整个20世纪,可以划分为四个阶段,每个阶段有不同的侧重点：第一阶段改革开始于19世纪末、20世纪初,“效率政府”是这一时期行政改革所追求的主要目标;第二阶段改革实施于20世纪中期,“忠诚政府”成为联邦政府改革的特点;20世纪70、80年代改革进入第三阶段,强调官员的职业道德,改革特点为追求“道德政府”;20世纪90年代美国政府管理进入一个全面调整时期,“重塑政府”成为行政改革追求的主要目标,从而在实践上把20世纪美国联邦政府行政改革推向了高峰。从行政管理学的角度分析,精简机构、节约开支和提高效率,始终是20世纪美国联邦行政改革的核心内容。从政治学的角度分析,防止职业官僚垄断政府权力和整治官僚主义作风,也始终是20世纪美国联邦政府行政改革必须面对的问题。     

2003年河南新乡市火电厂墓地发掘简报

2003～2004年,新乡市文物考古研究所发掘了新乡市火电厂251座战国晚期至西汉晚期墓葬,出土一批精美的彩绘陶器、大型铁制生活用品、铜器等遗物.根据墓葬形制和随葬品组合,将墓地分为五期,从战国晚期至西汉晚期,为研究中原战国至汉代文化提供了珍贵的实物资料.     

试论在美国的中国公民权益受侵犯及其保护

针对目前在美国的中国公民权益受侵犯案件时常发生的现状,结合对从美国回来的华侨进行的社会调查,从国际法的视角,分析了在美国的中国公民权益受侵犯的主要现象和原因;指出了侵犯在当地的中国公民权益,是对国际法上关于国际人权保护和反种族歧视原则的践踏;并就如何保护在美国的中国公民权益问题提出了自己的看法。     

明清时期汉水下游地区的地理环境与堤防管理制度

明清时期国家对于汉水下游的水利管理制度经历一个变迁的过程,与这一区域的水利问题的日益突出密切相关,垸田的发展以及带来的问题是主要的因素。钟祥至沙洋的汉江干堤极易溃决,并且关系到整个下游地区的安全,因此在人力组织、资金筹集、岁修维护上,国家的政策表现出明显的倾斜性,相对于沙洋以下的区域,给予了充分的重视。沙洋以下,天门、潜江、沔阳等州县所在区域主要以垸田为主,国家将这一区域的堤防修筑与维护主要交由地方来进行。垸堤岁修维护采取堤甲制的组织形式,由垸民完成,一方面没有固定的资金,另一方面在正常年景之下,垸民可以获得基本的物质生存,因此垸堤的维护面临相当的困难。