One-Dimensional Ground Response as a Preliminary Tool For Dynamic Analyses in Geotechnical Earthquake Engineering

This article discusses how to calibrate some parameters of two-dimensional finite element models for numerical analyses in geotechnical earthquake engineering. The calibration was made through the simulation of the one-dimensional vertical propagation of S-waves in elastic layers, whose theoretical solutions are available in literature. The numerical results were compared with those obtained by frequency domain analyses. The influence of several sources of damping arising in the model, including that deriving from boundary conditions and numerical integration, was investigated. The proposed calibration procedure constitutes a useful preliminary step for performing advanced dynamic analyses of any geotechnical system.     

Completeness Verification of Complex Response Spectrum Method for Underdamped and Overdamped Multiple-Support Systems Regarding the Decoupled Damping as Mathematical Parameter without Physical Meaning

The completeness of the complex response spectrum method for both formally underdamped and overdamped modes is theoretically proved, and the physical meanings of the decoupled modes as well as involved parameters are recognized and clarified in this paper. For the system with relatively large non-classical damping, the eigenvalue pairs generated by the complex mode decomposition method are real and the so-called modal damping ratios are larger than unity. In this paper, we firstly clarified that the decoupled modes are virtual and the so-called modal frequency and damping ratio are mathematical parameters that have no physical meaning. Then, the completeness of the complex response spectrum method for both formally underdamped and overdamped modes is rigorously proved by allowing the “damping frequency” to be an imaginary number. For the virtually overdamped modes, Duhamel integral involved in the calculation for formally underdamped modes automatically convert to hyperbolic Duhamel integral. A numerical example taken from the published literature is given to verify this method. Structural responses for the system with coupled damping under multi-support seismic excitations are further analyzed and numerical results indicate the accuracy of complex response spectrum method.     

Prediction of High-Damping Seismic Demands in Eastern North America

This article investigates high-damping seismic demands and associated damping reduction factors in Eastern North America (ENA). A database of hybrid empirical records with moment magnitudes M ≥ 6.0 is first studied to evaluate 5%- to 30%-damped seismic demands. A new magnitude- and distance-based equation is proposed to predict ENA spectral displacements and then used to characterize their sensitivity to variations in period, magnitude, epicentral distance and site conditions. The proposed equation is also used to assess damping reduction factors in ENA. The results contribute to improved assessment of seismic demands in ENA while accounting for added-damping in structural seismic design.     

A Procedure for the Displacement-Based Seismic Assessment of Infilled RC Frames

The aim of this study was to propose an extension of the displacement-based assessment procedure for infilled reinforced concrete (RC) frames. Two fundamental steps of the displacement-based approach were studied: the determination of the equivalent viscous damping and the definition of the limit-state displacement profile. The proposed criteria were derived by examining the results of two different numerical investigations regarding the nonlinear seismic response of single- and multi-story infilled RC frames. Lastly, the effectiveness of the method was verified through comparisons, in terms of displacement demand, with the results of nonlinear dynamic analyses.     

Russia's Energy Policy: A Framing Comment

A prominent specialist on the Russian economy provides a framing comment on two preceding papers entitled "Russia's Energy Policy" (by Vladimir Milov, Leonard Coburn, and Igor Danchenko) and "Russia's Energy Policy: A Divergent View" (by Matthew J. Sagers). The author argues that Russia's current energy policy should be viewed as an outcome of competition between three overlapping programs. In this context, he identifies three policy models—the old Soviet, the liberal or oligarchic, and the most recent state capitalist. The latter is currently supported by President Putin, who prioritizes diversification of the country's economy at the expense of diminished investments in the oil and gas sector. Journal of Economic Literature, Classification Numbers: L71, O13, Q40, Q48. 2 tables, 2 figures, 22 references.     

The Energy Dilemma of Belarus: The Nuclear Power Option

A specialist on Belarusian politics and society as well as on the impacts of the Chernobyl' nuclear power station accident on that country examines the factors shaping the current debate regarding construction of a nuclear power station in the eastern oblast of Mahileu (Mogilev). In particular, he analyzes the role played by a significant rise in the price of imported oil and gas from Russia, as well as increasingly strained political relations between the two countries. The paper outlines the discussions within the country on energy and economic issues, the new relationship with Russia, and the new power station, and offers a preliminary assessment of the feasibility of the nuclear power option. Journal of Economic Literature, Classification Numbers: H54, O18, Q40. 1 figure, 25 references.     

20世纪中美两国"专家政治"的缘起与演变--科学介入政治的一个历史比较

20世纪30年代专家政治的浪潮在美国达到一个峰巅。技术统治论的思潮与运动以物理学原理深刻反思资本主义制度，罗斯福新政时期也大量吸收专家参与政权。在此前后。《东方杂志》、《国闻周报》等将技术统治论作为新的思潮与运动加以介绍，一些参政知识分子则更多地从美国政府的政策调整中吸取经验。南京政府一定程度地吸收专家参政，在行政技术化、立法科学化等方面有一定改进，但未改变蒋介石专制政权的性质。美国的技术统治论经历复杂的转变，其中一部分为主流社会所吸收，一部分则趋向偏激，进一步产生对美国社会的深刻怀疑，成为当今美国社会的另类选择。美中两国历史发展说明，科学进入政治领域，有利于技术层面的科学化；科学主宰政治。却是技术乌托邦之梦。     

Influence of Ground Motion Duration on Damping Reduction Factor

This article investigates the influences of the effective ground motion duration (GMD) on damping reduction factor. The GMD are associated with 25 Chi-chi earthquake ground motion records and harmonic sine wave. The study shows that damping reduction factor decreases with the increasing of the damping ratio, and decreases with the increasing of the effective duration of the ground motion and the number of cycles of harmonic excitation. A nonlinear multiple regression analysis based on the statistical mean values of the present study is employed, and a modified damping reduction factor considering the effects of GMD is suggested.     

Resisting and Reconciling Big Wind: Middle Landscape Politics in the New American West

Abstract: While critical geographers have addressed how place politics impacts rural landscapes, less attention has been paid to the particular ways in which rural landscape identities are being impacted by the new energy economy. The nascent US wind energy opposition movement is evidence of broad, organized resistance to the landscape impacts associated with the re‐sculpting of rural energy geographies. Drawing from cultural landscape and place theory, this article examines the shifting terrain of wind opposition in the “New American West”. The article argues that wind energy opposition is fundamentally about who speaks for and negotiates conflicting social commitments to technology, economic values and an imagined American pastoral identity. By examining a case study of wind development in Nevada, this article considers how renewable energy development can constructively acknowledge the important role the “middle landscape” continues to play in American constructions of rural space.