Stability of Slender Masonry Columns with Circular Cross-Section under Their Own Weight and Eccentric Vertical Load

This work concerns the stability of unreinforced masonry slender circular cross-sectional columns subjected to their own weight and eccentric vertical load. Cantilever columns are examined, considering that the material has infinitely linear elastic behavior in compression and has no tensile strength. For the analysis, an existing numerical model and solution procedure developed for the stability analysis of masonry elements with rectangular cross-section are utilized and adapted to the circular columns. For the instability of the columns, an appropriate criterion that relates the top lateral deflection to the intensity of the applied eccentric vertical load is employed. By considering a reference column, critical buckling load is obtained, behavior of the column interpreted and efficiency of the numerical model emphasized. Performing a nonlinear buckling analysis using a general purpose software on this reference column, obtained results are compared with those of the adapted procedure of the present study. Implementing parametric analyses on reference column, effects of the column slenderness, eccentricity of vertical load, elastic modulus, and self-weight on the buckling load are investigated. Presented calculation procedure provides a useful tool in order to calculate the critical loads or to check the stability of masonry circular columns.     

Phase‐field modeling of epitaxial growth of polycrystalline quartz veins in hydrothermal experiments

Mineral precipitation in an open fracture plays a crucial role in the evolution of fracture permeability in rocks, and the microstructural development and precipitation rates are closely linked to fluid composition, the kind of host rock as well as temperature and pressure. In this study, we develop a continuum thermodynamic model to understand polycrystalline growth of quartz aggregates from the rock surface. The adapted multiphase‐field model takes into consideration both the absolute growth rate as a function of the driving force of the reaction (free energy differences between solid and liquid phases), and the equilibrium crystal shape (Wulff shape). In addition, we realize the anisotropic shape of the quartz crystal by introducing relative growth rates of the facets. The missing parameters of the model, including surface energy and relative growth rates, are determined by detailed analysis of the crystal shapes and crystallographic orientation of polycrystalline quartz aggregates in veins synthesized in previous hydrothermal experiments. The growth simulations were carried out for a single crystal and for grain aggregates from a rock surface. The single crystal simulation reveals the importance of crystal facetting on the growth rate; for example, growth velocity in the c‐axis direction drops by a factor of ~9 when the faceting is complete. The textures produced by the polycrystal simulations are similar to those observed in the hydrothermal experiments, including the number of surviving grains and crystallographic preferred orientations as a function of the distance from the rock wall. Our model and the methods to define its parameters provide a basis for further investigation of fracture sealing under varying conditions.     

东西互鉴：胡适诗学与意象主义关系再考察

胡适诗学致力于意象的构建与运用,主张以白话入诗,推崇朴实简约的诗风,追求诗体大解放。这与同时代大洋彼岸由埃兹拉·庞德引领的意象派主张有诸多相似之处。基于跨文化的视角,我们不难发现,这两个文学事件间的关系实际上源远流长,彼此遥相呼应,构成了一道特殊的文学景观。胡适的诗学思想是其中国基础、美国经验以及意象主义者的中国想象这三重资源碰触、融合的结果,是东西互鉴的产物,是中美文学、文化交流双向性特点的典型呈现。     

Japanese archaeology in the 1990s

As scientific archaeology takes hold in Japan, our understanding of the nature and content of Japanese prehistory is changing radically. All of the period boundaries of Japanese prehistory are being rewritten, and many new “archaeologies” are growing up around particular scientific techniques. New publications in English give greater access to archaeological thinking in Japan, while Japanese publications focus on ever-narrowing aspects of prehistoric lifeways. Policy changes are giving archaeologists more access to the imperial tombs, and rescue teams are under less obligation to “save everything” as selective preservation is instituted.     

东亚经济危机与东亚发展模式新探

本文从三个方面论述了东亚经济发展模式。首先,从历史的角度分析了东亚经济发展模式的产生、特点及其局限性。然后,进一步指出在经济全球化和信息化加速发展新的历史条件下,东亚发展模式已不能适应时代发展的要求,东亚发展模式与这次东亚经济危机存在着内在的必然的联系。最后,对东亚经济发展模式的发展与变革提出了自己的观点。     

Viking age horse graves from Kaunas region (Middle Lithuania)

Balts' territories have one peculiarity—large amounts of horse bones are found in burial grounds. This phenomenon is typical to the Prussians (5th–11th centuries) and Lithuanians (Kaunas region 8th–11th centuries) Horse burials of the 8th–11th centuries reflect the archaeological culture of Middle Lithuania most significantly. Several horse burial types have been defined on the basis of individuals; osteological signs and the archaeological data of the horse remains. A typical horse grave is when the whole horse was buried. Sometimes only a head or a head with forelegs, or scattered horse remains are found in a burial. The large number of burial grounds with an abundance of horse graves testifies to a very expressive ritual of horse offering in the Balts' region. On the basis of the data obtained, we determined that mostly 4–10 year old horses were buried in the grounds of Middle Lithuania. From the bone measurements, it has been determined that the length of metacarpals ranges between 180 and 216 mm (the average length 193.1±0.99 mm); the length of metatarsals between 218 and 253 mm (average length 233.9±0.73 mm).These data demonstrate that horses of different types were buried in Marvelė and Veršvai burial grounds (wither height 120–136 cm). A certain number of the larger horses (wither height 136–144 and 153 cm; length of metacarpals 210–222 mm) might not have belonged to local breeds. We have come to the conclusion that the most similar horse skeletons (according to the osteometric data) were found in Latvia. Copyright © 2001 John Wiley & Sons, Ltd.     

治理模式分异对旅游地发展的影响机制研究——阳朔遇龙河景区个案分析

如何实现有效治理是旅游目的地可持续发展中的重要议题。以阳朔遇龙河景区为个案,归纳其治理模式空间分异的类型与特征,解读不同模式对旅游发展的影响效应,发现：①村企共治模式中,各治理主体形成互助依赖的伙伴关系,资本互补、信任互惠、层级协同、信息对称、相互监督,能够兼顾效益、秩序与公平,游客满意度最高,呈现良性可持续发展态势;②社区主导模式中,治理主体权力失衡、信息不对称、短期工具理性、监管机制难以发挥持续实效,导致旅游秩序最差,游客满意度最低,不利于长远可持续发展;③政府主导模式中,政府公司治理能力不足,缺乏有效激励机制,导致商业效益较差,未能实现资源最优配置。     

新常态下中国人文地理学空间探究的时代宿命

本文从社会发展与区域科学承担的使命关系出发,论述人文地理学创新侧当代供给的使命,称为新人文地理学。在论述发达国家后现代人文地理学使命的基础上,依据"民本"性的新人本主义公正思想,首次系统论述主流新人文地理学研究空间公正结构的价值思想、理念与理论指向及其内容;其次,借鉴发达国家建构新人文地理学与社会及其区域学科的融合机理,具体地论证该学科具有对空间建构的最终人本判识学理性及其指向;中国已进入社会公平与空间公正建构的时代,本文争鸣性倡导国内人文地理学的研究必须从物质空间结构的景观功能研究转入到以提高人本价值生活质量的社会空间结构、行为空间结构与文化空间尊严结构的建构探讨方面。该方向不但是中国时代要求的使然,也是该学科对当代社会知识供给的宿命,同样也是与区域科学共同构建区域统筹发展与空间全面公正构建的学科融合宿命。在此基础上本文还首次提出社会与空间价值统一的"新区域经营理念"、"区域同步发展观"及其对应"空间体系价值统一规划"研究的新朝向。     

Wild galliform and gruiform birds (Aves,Galliformes and Gruiformes) in the archaeological record of Bulgaria

A total of 453 bones (294 of galliform and 159 of gruiform birds) from 28 archaeological sites are considered here, 34 per cent of the total ornithoarchaeological wild bird finds collected in Bulgaria so far. They cover a period from the Early Neolithic to the Middle Ages. Eleven species (six galliform and five gruiform), 87.5 and 45.5 per cent, respectively, of the Holocene avifauna of both orders, have been identified. One species, Tetrao tetrix, has totally disappeared and three others, Grus grus, Otis tarda and O. tetrax, now breed beyond the borders of Bulgaria and the Balkans. Some of the sites of the large gamefowl species indicate their wider distribution in the past. Phasianus colchicus is present as early as the Eneolithic period. The wild galliform and gruiform species were important as a source of meat for the local population up to the Middle Ages, in spite of widespread breeding of domestic poultry. © 1997 John Wiley & Sons, Ltd.