Dynamic Stability and Design of C-Bent Columns

Symmetrically reinforced bridge columns with a horizontal cantilever in one direction, called C-bent columns, tend to deform predominantly in the direction of applied moment when subject to strong earthquake shaking. For this reason, the strength in the direction of applied moment is generally increased in design. This article describes the use of inelastic dynamic time history analyses with a suite of ground motion records to quantify the amount of strength increase required to minimize likely peak and permanent displacement demands. It is shown that the strength should be increased by approximately 2.3 times the applied moment in design.     

孟姜女故事的稳定性与自由度

我们把所有具备“为死去的丈夫而哭倒长城”这一“标志性事件”的孟姜女故事称作“孟姜女同题故事”。对同题故事的所有母题进行合并同类项,我们就可以归纳出9个故事“节点”。故事的节点网络构成了一个自足的逻辑体系,某个节点被篡改后,必然会发生连锁反应,可能引起故事逻辑结构的全盘崩溃,或者导致原有故事主题的全面消解,因此,节点就成了同题故事中最稳定的因素。而只要故事家不篡改故事的节点,任何相容母题的进入,都不会影响到同题故事逻辑结构的变化。无论是在节点之上,还是节点之间,都存在巨大的想象空间,可以让故事家们充分地驰骋自己的文学想象,随人所愿地增添新的故事母题。要之,在故事的传承与变异过程中,传承的稳定依赖于节点的稳定,变异的随意是指节点之外的随意。     

Stability of Spatial Equilibrium*

Abstract. Asymptotic stability of equilibrium is often difficult to know when the number of variables exceeds four, since all eigenvalues of the Jacobian matrix are not analytically solvable. However, we obtain stability conditions for a general class of migration dynamics without computing eigenvalues. We show that a spatial equilibrium is stable in the presence of strong congestion diseconomies, but unstable in the presence of strong agglomeration economies. We also show existence of a stable equilibrium in the case of negligible interregional externalities, which is applicable to club goods, local public goods, and new economic geography.     

Regional Elections and Political Stability in Russia

A noted American specialist on regional affairs in the Russian Federation presents and analyzes a compilation detailing the political orientation of Russia's provincial executives. The data represent electoral results and include information from 68 provinces (49 oblasts, 6 krays, 10 autonomous okrugs, and 1 autonomous oblast) and 21 republics through September 1997. The discussion covers Russian regional politics, the results of regional elections held in 1996, and an assessment of alternative futures. Tabular material identifies the names of chief executives, dates of most recent elections, party support, and results relating to incumbency. Journal of Economic Literature. Classification Numbers: H77, D52, P41. 3 tables, 25 references.     

Stability in a Spatial Production and Trade System

Basic properties of the production and trade system for sulfur in the North Atlantic sphere are studied. Oligopolistic competition produces a more stable system than polypoly. Occasional exceptions, difficult to anticipate theoretically, are possible, however. When subjected to realistic exogenous shocks in consumption (demand), the system is less stable than if the shocks appear in supply.     

Afghanistan: Imperatives of Stability Misperceived

More than seven years have passed since the intervention of the international community in Afghanistan, yet the country has not only failed to achieve stability; it has actually experienced a downward trend on that account. The worsening situation in Afghanistan has occurred despite the fact that the Afghan government and its international partners have allocated unprecedented amounts of resources, increased their security forces and implemented socio-political and economic programs that they deemed were conducive to stability. Why and how this failure did come about? This article challenges some of the underlying assumptions for stability and the notion of political reconstruction that the international community and the Afghan government have implemented so far as being largely responsible for the gloomy state of affairs in that country.     

Equilibrium,Stability and Strength The Anatomy of Structural Performance

Abstract

Structures, contrary to general experience and expectation, do move. It is therefore the responsibility of the structural engineer, bearing in mind economy and materials, to decide how far he can go in his designs to control structural performance and to avoid failure. Here the basic principles are reviewed: calculating the strength of structures with computers, the complications when movement becomes significant, the structural properties which can cause trouble, when deflections can help and finally if it is possible to achieve a perfect structure.     

Consensus,Stability and Meaning in Abstract Social Values

The Social Goal Values Inventory comprises 18 abstract principles that represent people's shared understandings of the good society. While measuring consensus, this instrument also assesses differences in how these shared values are prioritised. Responses from two different community samples were compared across a 20-year period to examine the related issues of consensus and stability in Australian values. Data were analysed at the level of individual items, underlying value orientations (security and harmony) and value types (the security oriented, the harmony oriented, dualists, and relativists). Shifts in individual values over time were meaningful in the context of changes in Australian political culture. The overall picture, however, was one of consensus and stability, with no evidence of value commitment waning in favour of relativism. The findings of this paper are used to support the argument that values as stable individual and socially shared phenomena are ideally located for bridging the gap between micro and macro social processes.     

Seismic Stability of Slope Considering Rayleigh Wave

In the present paper factor of safety of slope under seismic loading condition is evaluated assuming circular failure surface. Using Fellenius method the center of most critical circle is located. Adopting limit equilibrium method, under the influence of weight of potential sliding mass and seismic inertia forces, factor of safety is evaluated considering Rayleigh wave along with primary wave and shear wave. Results are presented and compared with the available results from literature. Detailed parametric studies are also carried out to observe the variation of safety factor at different soil strength and seismic forces.     

中东过度城市化与社会稳定

城市化是世界各国经济社会发展的必由之路,但二战后中东国家的城市化发展模式与西方发达国家城市化发展的历史经验大不相同,实行的是以西方城市化为参照目标的赶超战略,导致严重的过度城市化现象。中东过度城市化的畸形发展引发一系列城市化问题,并对中东地区的社会稳定构成重要影响,体现在过度城市化孕育着不稳定的社会心理;过度城市化危及社会秩序稳定;过度城市化对城市社会结构产生影响,扩大底层社会的基础。     

Stability and conservation of the Maxentius Basilica in the Roman Forum

Abstract

Originally extended over 6500 square metres, the Basilica of Maxentius was one of the biggest and most outstanding buildings of Roman architecture. Only one third of the monument is still standing. In celebration of the Christian Holy Year of 2000 (the Jubilee), the Soprintendenza Archeologica di Roma (SAR) started an extended project with the purpose of restoring the terrace and of studying the structural problems of the monument. CISTeC was appointed to the structural part of the project, including the study of the foundations and the proposal for the consolidation project.

The present paper reports the conclusions of the static and dynamic studies that were carried out both on the present-day Basilica and on the model of the original basilica. The results concluded that the monument could be subjected to seismic risks. Following such conclusions, a provisional consolidation project (which is currently in progress) and three final consolidation proposals were submitted to SAR. The immediate application of the provisional consolidation will give time to SAR to decide which of the final projects is the most Suitable, while still protecting and preserving the monument. The structural studies and the projects are briefly described in this paper.     

维也纳体制的稳定及其瓦解

维也纳体制是 1 9世纪欧洲和平得以维系的基本条件 ;维也纳体制及其均势结构持续存在的基础在于欧洲对世界的统治。 1 9世纪末 2 0世纪初 ,整个世界一系列变数的冲击最终导致维也纳体制不可避免地走向瓦解。     

Perceptions and Misperceptions of Regime Stability and Iran's Convoluted Rise to Regional Influence

This article seeks to explain revolutionary Iran's convoluted rise to regional prominence over the last three decades. We hold that perceptions and misperceptions of regime stability (both of one's self and of others) by the relevant actors have played a major role in Iran's recent. The main logic is that the success of many strategies employed by relevant regional actors to augment their regional influence (both Iran seeking more influence and others seeking to stem that influence) have crucially hinged on making correct assessments of regime stability. This study has both theoretical and empirical findings. Theoretically, we find that failures to accurately estimate regime stability stem from three main sources: (1) objective uncertainties regarding the target state's level of regime stability, given the high strength of societal forces shaping state‐society relations in the Middle East and given the distinct variation between autocrats in terms of their ability to develop effective counterrevolutionary/repressive tools; (2) ideological blinders, from which both the United States and regional actors frequently suffer, which have often led them to be falsely optimistic regarding the existence of either subversive opportunities or opportunities to stabilize regimes facing domestic pressures; and (3) incorrect theories regarding sources of regime stability which lead experts and policymakers to overlook factors which may destabilize a regime. This article has two major empirical findings. First, Iran's rise may be at least partly attributed to Iran demonstrating a slightly better learning curve at the tactical level (i.e., learning subversive skills from its Lebanese experience in the 1980s–1990s and applying them to Iraq in the 2000s–2010s) as well as at the strategic level (i.e., understanding the limits of its subversive capacities and correctly assessing when it can engage in successful stabilizing operations). Second, two errors committed by the United States have been far more consequential than those committed by Iran for the regional balance of power: First, the George W. Bush Administration myopically opened up subversive opportunities for Iran when it invaded Iraq in 2003 by thinking that it could stabilize a democratic regime and insulate it from outside influence; second, on two occasions Washington overestimated the transformative effect that its concessions to Iran would have in terms of sufficiently empowering reformists so as to bring about complete regime transformation from within.