Variability in Wood-Frame Building Damage using Broad-Band Synthetic Ground Motions: A Comparative Numerical Study with Recorded Motions

Earthquake damage to light-frame wood buildings is a major concern for North America because of the volume of this construction type. In order to estimate wood building damage using synthetic ground motions, we need to verify the ability of synthetically generated ground motions to simulate realistic damage for this structure type. Through a calibrated damage potential indicator, four different synthetic ground motion models are compared with the historically recorded ground motions at corresponding sites. We conclude that damage for sites farther from the fault (>20 km) is under-predicted on average and damage at closer sites is sometimes over-predicted.     

The use of forest resources in central Iberia during the Late Iron Age. Insights from the wood charcoal analysis of Pintia,a Vaccaean oppidum

Charred woods may be used to effectively reconstruct past wood acquisition strategies. We used anthracological data from the pre-Roman settlement of Pintia (Padilla de Duero, Valladolid) to examine the use of forest resources at the local scale. Palaeoecological data revealed heterogeneous landscapes in the inland northern meseta with environments that offered diverse sources of wood for the inhabitants of Pintia, one of the first cities of inland Iberia. Pines (Pinus pinea/pinaster and Pinus sylvestris/nigra) and both evergreen and deciduous Quercus L. and Juniperus L. were the main taxa identified as both fuelwood and construction elements, but the assemblages and frequencies of these taxa differed depending on their use. We also examined the potential of models from human ecology by considering the frequency, handling time and the relative technological value of each taxon to model how people gathered wood resources. The results suggest that although local availability affected the forest resources that were used by the Vaccaei people, specific taxa were positively selected for specific uses.     

郑州商城青铜大方鼎造型与纹饰研究

郑州商城的三处青铜器窖藏共出土了八件青铜大方鼎,目前学界一般认为铜方鼎的原型与陶方鼎有关。但通过造型与纹饰的细节分析,可发现大方鼎的原型应为方形木质容器,乳钉纹带模仿了容器边套、箍圈上的成排铆钉。南顺城街窖藏的四件大方鼎,其纹饰的演变体现出从模仿铆钉原型到向装饰化发展的过程。     

A Study of the Techniques Used to Make Laohudong Guan Ware in China in the Southern Song Dynasty

Through a combination of analysis and synthesis of Laohudong Guan ware shards from Hangzhou City in southern China, some new hypotheses concerning Guan ware manufacture can be proposed. These suggest that the complex microstructures seen in Guan ware glazes, and which contribute significantly to their jade‐like qualities, may owe much to layers of fine bubbles trapped during the glazing process. It is also proposed that the multi‐layer glazing methods used at the Guan ware kilns at Hangzhou may have helped initially to disguise the relatively coarse and ferruginous clays used for Guan ware manufacture. Once established, the layered glazing technique was used for its own sake—eventually yielding wares that could comprise more glaze than clay. Raw materials and firing temperatures were also explored for this study, and these suggest the use of porcelain‐stone/wood ash mixtures for glaze‐making, with 20–30% calcareous wood ash being the usual amounts. The average heat‐work for the glaze firing seems to have been equivalent to Orton Cone 7, giving a typical finishing temperature of ～1215°C. A single biscuit firing and a single glaze firing seem likely for most Laohudong Guan wares. Studies of the losses that occur in the preparation of calcareous wood ashes suggest that very large quantities of botanic material must have been burned to provide ash for glaze‐making at the Laohudong kiln. From the environmental perspective, a combination of thick glazes and heavy wood‐ash usage would have placed great demands on local fuel supplies.     

基于古建木构文物修缮的木材抗弯性能实验研究

受自然作用、人为因素及材性退化的影响,已有数百年甚至千年历史的古建筑木结构构件及斗栱节点存在不同程度的损伤,需进行合理修缮加固。而在木结构修缮选材中,抗弯弹性模量是需要考虑的一项重要指标。为了找到更合适的古建筑修缮加固用材,本研究选用五种木材进行横纹径向、弦向和斜向抗弯测试,采用力学试验机以及自制的力传感器通过电阻应变采集仪分别记录了五种木材所受力和位移的关系,然后按荷载与位移的关系分别计算出各自的抗弯弹性模量。通过对五种木材抗弯弹性模量的测量与分析,比较了相同含水率的木材抗弯弹性模量随密度的变化情况。试验表明:同种木材不同受弯方向抗弯弹性模量差异较大;与其他木材相比,落叶松不同受弯方向的平均抗弯弹性模量高于其他木材;木材的抗弯弹性模量有随密度增加而增加的趋势。此试验结果可为今后古建木结构的维修与加固以及构件替换提供参考。     

江陵天星观一号楚墓出土饱水木漆器F455中细菌对硬松木的腐蚀研究

研究木质文物中的细菌对木材腐蚀性影响,筛选防腐剂抑制腐蚀性强细菌的腐蚀作用,是延长木质文物保存期的一种有效的生物保护措施。为研究饱水木漆器F455及其水环境中细菌的种类,以及对木材的腐蚀程度,采用16S rRNA基因序列分析方法及生理生化试验,对饱水木漆器F455及水环境中细菌进行鉴定,并选取典型菌按5×10~8个/瓶菌量接种马尾松心材(悬于无菌自来水中),37℃培养120d,测试木材的损失率。结果发现,从F455文物挑选的32株细菌中,有29株菌鉴定为芽孢杆菌属(Bacillus),为优势菌属,其余为短杆菌属(Brevibacterium)、短波单胞菌属(Brevundimonas)和产碱杆菌属(Alcaligenes)各1株。水样样品中细菌菌属较F455文物样品中丰富,27株菌有9个属,其中短杆菌属(Brevibacterium)有9株,为优势菌属,其余交替赤细菌属(Altererythrobacter)有5株,短波单胞菌属(Brevundimonas)有4株,产碱杆菌属(Alcaligenes)有3株,黄杆菌属(Flavobacterium)有2株,芽孢杆菌属(Bacillus sp.)、白色杆菌属(Leucobacter)、类芽孢杆菌属(Paenibacillus)、苍白杆菌属(Ochrobactrum)各1株。从2种样品材料的分离菌中共挑选出14株典型菌进行木块腐蚀试验,与对照组比较,其中有9株菌差异极显著。说明这些菌对马尾松木材有一定的腐蚀作用,但是腐蚀率非常低,最高仅1.56%。表明这些细菌对试验木材马尾松腐蚀并不严重。该研究分析了饱水木漆器长期保存在水槽中细菌对木漆器的影响,丰富了饱水木漆器文物生物影响的理论依据。     

Selected physical parameters to characterize the state of preservation of waterlogged archaeological wood: a practical guide for their determination

Non-destructive and destructive methods for determining the physical parameters of waterlogged wood such as the porosity, the water content, the wet and dry bulk densities plus the density of the cell wall material are presented. Considerations in respect to determination of masses, volumes and sampling size are discussed.     

Wood identification of a wooden mask using synchrotron X-ray microtomography

Recently, an old wooden mask was discovered at Yatsushiro city, Kumamoto Prefecture, Japan. This mask has been handed down from the end of the 16th century; a Japanese man of arms brought it from the Korean Peninsula during the war between Japan and Korea. In the Korean Peninsula, Hahoe masks have been stored in the Hahoe village and were designated as national treasures in 1964 and are presently possessed by the National Central Museum. Some concerns existed that this wooden mask could be one of the Hahoe masks. Since the Hahoe masks in Korea have all been made of alders (Alnus spp.), wood identification became a key issue to answer the abovementioned concerns. In fact, a flaked sample fragment was available and it was small and brittle enough to be sectioned without embedding. Furthermore, the sample was compressed in the tangential direction so that the surface was not clear enough to be explored by a scanning electron microscope. In this study therefore, a synchrotron X-ray microtomography at SPring-8 was used for the first time for wood identification. The experimental setup of BL20XU at SPring-8 allowed us to image any wood sample at a special resolution of 0.5 μm, which is enough to explore most anatomical features for wood identification established using optical microscopy. The sample was clearly diffuse-porous hardwood characterized by uniseriate heterogeneous ray and simple perforation. As a result, the mask turned out to be made of Salix sp., and the possibility that it is one of the Hahoe masks was ruled out.     

Beyond ‘the toad beneath the harrow’: geographies of ecological science, 1959–1965

This paper traces the distinctive shifts in ecology and conservation in Britain during the late 1950s and 1960s. These were the last six years of the Nature Conservancy, the state research council responsible for ecological research, the conservation of nature, and for providing expert advice. Drawing on work in science studies and the geography of science, the paper addresses the changing spatialities of official ecological knowledge and the ordering of nature in this period of British modernity. The paper examines the Conservancy's construction of the form and relationship of research to practice: the connections between local spaces of research – the laboratory and the nature reserve – to the ‘right’ government of land and management of resources more universally. This putative ‘single great mission’ is traced through examination of the politics and practices of doing ecological research at the time, including the creation of a new Experimental Station, the growth of ecology as public discourse, and, importantly, government reviews of science. The paper concludes by considering how this mission was tempered and reconfigured by institutional change.     

数字X光照相技术在木雕造像上的应用

X光照相是一种传统的无损检测技术,广泛应用于各类文物的检测分析中。近年来,随着数字成像技术的逐步兴起,大大简化了X光照相的操作过程,得到的数字图像更容易观察、使用和存储,图像的编辑也成为可能。X光照相技术因此有了更大的发展空间。以一尊木雕造像为例,介绍了数字X光照相的操作过程,X光片经过编辑处理,最终得到了检测对象的X光照相三视图,并对其进行了分析和讨论。