The Shaking Frequency Effect in the Dynamics of a Model Sandy Layer

Experimental results showing the frequency-dependent behavior of both dry and saturated sandy layers subjected to a horizontal excitation on a shaking table are presented. The largest settlements of a dry layer correspond to two specific frequencies. In the case of a saturated layer, there is a single peak frequency corresponding to the largest depth of sinking of a measuring plate in liquefied subsoil. The first peak of settlements coincides with the single peak of sinking in liquefied soil. The eigenfrequencies of the layer were estimated. A modification of the compaction law was proposed for low shaking frequencies.     

Contact Dynamics of Masonry Block Structures Using Mathematical Programming

A simple variational formulation for contact dynamics is adopted to investigate the dynamic behavior of planar masonry block structures subjected to seismic events. The numerical model is a two-dimensional assemblage of rigid blocks interacting at potential contact points located at the vertices of the interfaces. A no-tension and associative frictional behavior with infinite compressive strength is considered for joints. The dynamic contact problem is formulated as a quadratic programming problem (QP) and an iterative procedure is implemented for time integration. Applications to analytical and numerical case studies are presented for validation. Comparisons with the experimental results of a masonry wall under free rocking motion and of a small scale panel with opening subjected to in-plane loads are also carried out to evaluate the accuracy and the computational efficiency of the formulation adopted.     

Experimental Dynamic Behavior of Free-Standing Multi-Block Structures Under Seismic Loadings

This article describes the dynamical behavior of free-standing block structures under seismic loading. A comprehensive experimental investigation has been carried out to study the rocking response of four single blocks of different geometry and associations of two and three blocks. The blocks, which are large stones of high strength blue granite, were subjected to free vibration, and harmonic and random motions of the base. In total, 379 tests on a shaking table were carried out in order to address the issues of repeatability of the results and stability of the rocking motion response. Significant understanding of the rocking motion mechanism is possible from the high quality experimental data. Extensive experimental measurements allowed to discuss the impulsive forces acting in the blocks and the three-dimensional effects presented in the response.     

广西越州故城遗址玻璃珠饰的科学研究

本研究利用能量色散型X射线荧光光谱分析、共聚焦激光拉曼光谱分析、光学相干层析成像、超景深光学显微观测等多种方法对广西越州故城遗址出土的印度-太平洋玻璃珠饰进行科技分析,获取了玻璃珠的化学成分、物相结构、内部物理结构、表面显微形貌等综合物理化学信息,确定了玻璃珠的玻璃体系、制作工艺(着色工艺、成形工艺)和产地来源,探讨了以丝绸之路为主线的国内发现魏晋南北朝时期印度-太平洋玻璃珠可能的输入路线。广西越州故城遗址发现的印度-太平洋玻璃珠为中外文明交流提供了新实物证据,对深入研究我国南北朝时期中外文明交流具有十分重要的学术价值和研究意义。     

Shock Response from Pseudodynamic Test Using Momentum Equations of Motion

The feasibility of using pseudodynamic techniques to yield shock responses from impulses is studied herein. A direct integration method is often used to solve the force equation of motion in performing a conventional pseudodynamic test. However, this technique might not be applicable to obtain an accurate shock response from an impulse as a load discontinuity occurs at the end of the impulse. This is because this discontinuity will lead to an extra amplitude distortion and the amount of this amplitude distortion is increased with the increase of time step. Hence, a small time step is needed to reduce the extra amplitude distortion and thus the displacement increment for each time step might be smaller than or as small as the resolution of the displacement transducer. As a result, the displacement increment cannot be accurately imposed upon the specimen and the responses will be contaminated by the noise. In addition, the test duration is drastically increased. Alternatively, this difficulty might be overcome if the momentum equation of motion instead of the force equation of motion is solved pseudodynamically. Hence, an external momentum is used in the solution of the momentum equation of motion. Since the external momentum is a resultant of the time integration of the external force the discontinuity problem will automatically disappear. Consequently, reliable shock responses can be obtained from pseudodynamic tests.     

The Baseline Stiffness Method for Damage Detection in Buildings Without Baseline Modal Parameters

A new method called the Baseline Stiffness Method (BSM), used to locate and quantify damage in buildings without baseline modal parameters (undamaged state), is presented. In order to determine this reference state, the BSM uses modal parameters from the damaged state of the building and the lateral stiffness matrix of the first story without damage. Afterwards, by means of an iterative process using singular value decomposition, location and severity of damage are obtained by comparing information about the damaged and non damaged states. Numerical and experimental examples are presented and discussed showing the advantages of the application of the proposed BSM.     

Contact,conflict and geography: What factors shape cross-border citizen relations?

Political geographers frequently argue that European borderlands, due to geographical proximity and cross-border contact, are sites of particularly good citizen relations. However, they have not put forward any general theory of the effect of cross-border contact on perceptions. This paper shows that social psychological contact theory, if applied to borderlands studies, can uncover the factors that influence citizen relations across national borders and under what conditions.Using opinion poll data from the Czech–German border region as an example, this paper shows that the Saxon and Bavarian regions bordering the Czech Republic are areas of high interaction density. Mediator analysis is used to decompose the direct and indirect effects of geographical proximity and contact on attitudes towards the Czech neighbours.Contact in the Saxon border region produces more favourable attitudes than elsewhere in Germany. However, contact does not have the same effect in the Bavarian border region: Bavarian attitudes are less favourable than elsewhere in Germany. The paper shows that Bavarian–Czech relations are weighed down by historical stumbling blocks, notably the influence of the post-World War II expellees from Czechoslovakia who are an important political force in Bavaria. The expellees issue demonstrates the need to take into account cultural factors when applying contact theory to the borderlands context.     

Technological Change and the Archaeology of Emergent Colonialism in the Kingdom of Hawai‘i

Archaeologically informed history is vital for examining the consequences of emergent colonialism in the nineteenth century and earlier, since documentary sources are silent on many facets of everyday life. Interpretations of contact and colonialism in Oceania often highlight rapid changes in the technologies and practices of its traditional island societies. In Hawai‘i, the top-down imposition of indigenous elite power greatly influenced the rate and character of technological change, as commoner access to European and American goods was initially curtailed in this highly stratified society. Although indigenous elites purposively used imported goods and technologies to materialize their hybrid identity—and to expand their political and economic power—this phenomenon presaged the development of unrestrained colonialism by Euro-Americans in the late nineteenth century. This study illustrates the need to examine a range of cultural and historical contingencies in studies of technological change during periods of emergent colonialism.     

Effect of AAC Infill Walls on Structural System Dynamics of a Concrete Building

The effect of autoclaved aerated concrete (AAC) infill walls on the structural system dynamics of a two-story reinforced concrete building is investigated using its finite element structural model, which is calibrated to simulate the acceleration-frequency response curves from its forced vibration test. The model incorporating the AAC infill walls by equivalent diagonal struts captures the increase in lateral stiffness of the building and the torsional motions induced due to the asymmetrically placed AAC infill walls. A higher strut width coefficient than in ASCE/SEI 41-06 is recommended to model the stiffness of the AAC infill walls in the elastic range.     

Major and Minor Turkic Language Islands in Iran with a Special Focus on Khalaj

This contribution offers a presentation of Turkic languages in Iran with special focus on Khalaj, a non-Oghuzic language spoken in the Markazī province. Attention is paid to features induced by contact with Iranian languages in particular with regard to the anaphoric pronominal stem bilä-, necessity constructions and the multifunctionality of ki/ke, providing new data on Khalaj and offering significant insights for further research.