单檐歇山式木构古建抵抗极端烈度地震试验调查研究

为更好地保护我国古建筑,基于《单檐歇山式古建筑抗震性能振动台试验》的相关成果,研究了强震作用下我国明清官式木构古建的抗震性能,制作了与该论文相同的试验模型,进行了振动台试验。通过对模型输入烈度逐渐增强的1940年El-centro波,并考虑地震波为水平双向作用,分析了强震作用下不同构造的试验现象,开展了详细的震后调查,获得了不同构造在强震作用下的抗震性能和震害机制。结果表明:强震作用下,我国明清官式木构古建的振动形式表现为柱架、斗拱、梁架及屋顶的近似同步往复摇摆;主要震害包括柱底偏移、榫卯节点开裂、拔榫、斗拱偏移及错位、额枋-垫板分离、墙体倒塌等,但承重木构架受损不严重,结构未产生倒塌。其良好抗震性能的原因与古建筑的构造特征密切相关。     

自贡盐业铁工具的防锈保护

通过对馆藏盐业铁工具的锈层性状及结构的检测分析,并结合当地环境气候特征,认为其继续锈蚀的机制是电化学循环机制,提出除去有害锈、涂料封护的CLFJ防锈法。CLFJ防锈法处理生成的表面膜经防锈性检测,耐CuSO_4滴液、耐盐水性及耐水性指标全部合格,经模拟自然暴露3年条件下工业大气浸蚀的加速实验表明,馆藏条件下防锈时效性指标达5年以上;同时,表面膜呈现出贴近原貌的铁锈色。     

Variability and sampling strategy of cave wall concretion: Case study of the moonmilk found in Leye Cave (Dordogne)

Cave Art is a fragile testimony of past human societies and the development of modern behaviours. In limestone caves, moonmilk commonly endanger the artworks. It is a calcite deposit with a large variability of chemical composition and morphological structures and it hosts numerous microbial communities. The possibility to characterize this deposit in the field would aid in a better understanding of cave behaviour and allow the setting up of proper conservation measures. The present study analyses the variability of a moonmilk strip of metric size in Leye Cave in the Vézère Valley (Dordogne, France). The cave was not ornate and was selected as a laboratory cave in which in‐situ observations and micro‐sampling could be carried out, before they were performed in cavities hosting parietal artworks. Scanning electron microscope (SEM) observations of 24 samples allowed, for the first time, an investigation of the variability of moonmilk deposits over the same wall of a few metres dimension. The observations highlighted the low variability of the moonmilk at the microscopic scale when regarding the chemical composition and morphological structures, despite significant macroscopic diversity, thus providing insights into how to optimize the sampling strategy of moonmilk in ornate caves.     

THE γ-FUNCTION PSEUDODYNAMIC ALGORITHM

Practical applications of the γ-function dissipative explicit method to pseudodynamic tests are thoroughly investigated herein. Detailed implementation of this pseudodynamic algorithm is schematically sketched. Numerical experiments and verification tests strongly indicate that the γ-function dissipative explicit method can effectively filter out the spurious participation of high frequency responses while the lower mode responses can be obtained very accurately. In addition, error propagation analysis also shows that the γ-function dissipative explicit method possesses much better error propagation characteristics when compared to the Newmark explicit method. Thus, this pseudodynamic algorithm is very suitable for the test system where the responses are dominated by the low frequency modes and the high frequency responses are of no interest.     

SIMULATION OF NONLINEAR SOIL-STRUCTURE INTERACTION ON A SHAKING TABLE

A new method to simulate soil-structure interaction effects in shaking table tests has recently been presented by the authors. In this method, analog circuits or digital signal processors are used to produce soil-foundation interaction motions in real time. Their expressions of soil-structure interaction motions are based on published rigorous formulations of impulse response functions or flexibility functions of foundations resting on or embedded in homogeneous or layered soils of semi-infinite extent. In this paper the method is further extended to take the “far field” soil non-linearity into account. An example of non-linear soil-structure interaction simulation using the present method is also described.     

Scaling ceramic provenience at Lydian Sardis,Western Turkey

We present a multistage strategy to define the scale and geographic distribution of ‘local’ ceramic production at Lydian Sardis based on geochemical analysis (NAA) of a large diverse ceramic sample (n = 281). Within the sphere of local ceramic production, our results demonstrate an unusual pattern of reliance on a single resource relative to other contemporary Iron Age centers. When our NAA results are combined with legacy NAA provenience data for production centers in Western Anatolia, we can differentiate ceramic emulation from exchange, establish probable proveniences for the non-local component of the dataset, and define new non-local groups with as yet no known provenience.     

TECHNICAL NOTE A FRAMEWORK FOR MULTI-SITE DISTRIBUTED SIMULATION AND APPLICATION TO COMPLEX STRUCTURAL SYSTEMS

In this technical note, the development of a framework for multi-site distributed simulations is presented. The algorithm is suitable for any combination of physical (laboratory) and analytical (computer) distributed simulations of structures, their foundations and the underlying sub-strata subjected to static and dynamic loading. Two examples of multi-site testing and multi-platform simulation are given. The main contribution in this note is the separation between time-step integration and stiffness formulation, which enables the use of static analysis and testing as modules of the main control module referred to as the simulation coordinator. The approach proposed is intuitive, simple and efficient. It is therefore recommended for use in distributed analysis using different programs, distributed testing facilities (e.g. the NEES equipment sites) or a combination of analysis and testing.     

Determining the use of Late Archaic shell rings using lithic data: “ceremonial villages” and the importance of stone

ABSTRACT

Late Archaic shell rings have been the focus of archaeological research for decades, yet their history, use, and function are debated. Relying on an evidentiary line rarely used in shell ring studies – the analysis of stone tools and debitage – we test prevailing theories and find that models describing the rings as circular dams intended to hold freshwater are incorrect. Instead, by tracing the origins of stone and its distribution within two shell rings on St. Catherines Island, Georgia, we posit that shell rings were places of both daily residence and intermittent gatherings. Because they have proven useful in interpreting the St. Catherines Island shell rings, we suggest archaeologists shift their sampling and recovery techniques so that representative lithic assemblages can be attained from other rings, thereby providing a better understanding of ring-builders and the Late Archaic occupation of the South Atlantic coastline.     

“I think that would be the end of Canada”: Howard Green,the Nuclear Test Ban,and Interest-Based Foreign Policy, 1946–1963

Canada's atomic arms debate has attracted considerable scholarship, yet one of the debate's chief protagonists, Canada's Secretary of State for External Affairs Howard Green, has received comparatively little attention. In the fall of 1959 Green abruptly moved against further nuclear testing, and began a crusade against Canadian acquisition of atomic weapons. By exploring Howard Green's understanding of nuclear fallout and subsequent actions regarding nuclear testing, this article examines the validity of existing explanations for Green's abrupt change of heart and proposes a new primary motivation: that advancements in science's understanding of the environmental impact of nuclear fallout led Green to redraw his “mental map” of Canada's interests.     

Sticky stories,fluid narratives,or vanishing tales: The fate of ‘nations’ in a globalised world

In the scientific methodology of Karl Popper the following deductive sequence is stressed: initial problems, tentative solutions, error elimination, resultant problems. This sequence produces two difficulties, concerning the source of the initial problems and the criteria for testing the proposed solutions. Discussion of these problems is relevant to geography, where they have arisen as in any other science. Particularly relevant to geography is Popper's scheme of the “three worlds”: World 1, objective reality; World 2, subjective consciousness and appraisal; World 3, objective knowledge. Geographers study not merely World 1 but rather its logical articulation in World 3. Acceptance of such a scheme helps to reduce not only any supposed dichotomy between physical and human geography but also any supposed division between field workers and so‐called “armchair” geographers. The open‐ended approach of Poppsr's deductive sequence leads naturally to the problems of prediction and planning. The Popperian philosophy of science is finally briefly contrasted with that of T. S. Kuhn when the paradigm concept is called in question.