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.     

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。     

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.     

Numerical Assessment of Frictional Heating in Sliding Bearings for Seismic Isolation

This article proposes a numerical investigation of the frictional heating developed in sliding bearings under high velocities and the influence of the relevant temperature rise on the mechanical characteristics of the device. A three-dimensional finite element model of the bearing is created and frictional heat generation is modelled through a thermal source inserted at the sliding surface of the bearing, with intensity dependent on the coefficient of friction, the contact pressure and the velocity. The friction value is adjusted step-by-step on surface temperature and velocity and used to update the thermal flux and the resisting force developed by the bearing. The numerical predictions of temperature histories and force–displacement loops are compared with the results of laboratory tests to validate the numerical approach. The procedure can help in preliminary studies for the selection of bearing materials accounting for their thermal stability and for the estimation of change of design properties of sliding isolation bearings due to frictional heating.     

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.     

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.     

Detection of diffusion and contact zones of early farming in Europe from the space-time distribution of 14C dates

The spread of early farming in Europe is revisited using a sample of 3072 audited 14C calBC dates from 940 georeferenced early Neolithic sites. The surface expansion of early Neolithic has been reconstituted using the kriging technique of spatial interpolation. Centres of renewed expansion, of contact zones, and the main routes of expansion have been highlighted by means of a vector map, representing the gradient. The expansion of the agricultural system on the map, was not uniform and regular across Europe as a whole, but proceeded in leaps. With the scale of detection of the 500-year isochrones, several leaps are identifiable: at 8000 calBC crossing the Taurus barrier, 6700–6100 calBC crossing the southern Adriatic barrier, 6100–5600 calBC crossing the Central European agro-ecological barrier and 5000–4000 calBC expanding on the other, marginal zones. Using a vector map, 10 points of renewed expansion and nine contact zones, were detected. The whole does not correspond to a process of homogeneous diffusion, approximately steady, but a process marked by phases of geographical expansion and stasis.